Sample records for factor nrf2 nuclear

  1. Competition of nuclear factor-erythroid 2 factors related transcription factor isoforms, Nrf1 and Nrf2, in antioxidant enzyme induction☆

    PubMed Central

    Chepelev, Nikolai L.; Zhang, Hongqiao; Liu, Honglei; McBride, Skye; Seal, Andrew J.; Morgan, Todd E.; Finch, Caleb E.; Willmore, William G.; Davies, Kelvin J.A.; Forman, Henry Jay

    2013-01-01

    Although the Nrf2 (nuclear factor-erythroid 2 p45 subunit-related factor 2) regulated expression of multiple antioxidant and cytoprotective genes through the electrophile responsive element (EpRE) is well established, interaction of Nrf2/EpRE with Nrf1, a closely-related transcription factor, is less well understood. Due to either proteolysis or alternative translation, Nrf1 has been found as proteins of varying size, p120, p95, and p65, which have been described as either activators of EpRE or competitive inhibitors of Nrf2. We investigated the effect of Nrf1 on EpRE-regulated gene expression using the catalytic and modifier subunits of glutamate cysteine ligase (GCLC and GCLM) as models and explored the potential role of Nrf1 in altering their expression in aging and upon chronic exposure to airborne nano-sized particulate matter (nPM). Nrf1 knockout resulted in the increased expression of GCLC and GCLM in human bronchial epithelial (HBE1) cells. Overexpression Nrf2 in combination with either p120 or p65 diminished or failed to further increase the GCLC- and GLCM-EpRE luciferase activity. All known forms of Nrf1 protein, remained unchanged in the lungs of mice with age or in response to nPM. Our study shows that Nrf1 could inhibit EpRE activity in vitro, whereas the precise role of Nrf1 in vivo requires further investigations. We conclude that Nrf1 may not be directly responsible for the loss of Nrf2-dependent inducibility of antioxidant and cytoprotective genes observed in aged animals. PMID:24024152

  2. Glycogen synthase kinase 3 regulates expression of nuclear factor-erythroid-2 related transcription factor-1 (Nrf1) and inhibits pro-survival function of Nrf1

    PubMed Central

    Biswas, Madhurima; Kwong, Erick K.; Park, Eujean; Nagra, Parminder; Chan, Jefferson Y.

    2013-01-01

    Nuclear factor E2-related factor-1 (Nrf1) is a basic leucine zipper transcription factor that is known to regulate antioxidant and cytoprotective gene expression. It was recently shown that Nrf1 is regulated by SCF-Fbw7 ubiquitin ligase. However our knowledge of upstream signals that targets Nrf1 for degradation by the UPS is not known. We report here that Nrf1 expression is negatively regulated by glycogen synthase kinase 3 (GSK3) in Fbw7-dependent manner. We show that GSK3 interacts with Nrf1 and phosphorylates the Cdc4 phosphodegron domain (CPD) in Nrf1. Mutation of serine residue in the CPD of Nrf1 to alanine (S350A), blocks Nrf1 from phosphorylation by GSK3, and stabilizes Nrf1. Knockdown of Nrf1 and expression of a constitutively active form of GSK3 results in increased apoptosis in neuronal cells in response to ER stress, while expression of the GSK3 phosphorylation resistant S350A–Nrfl attenuates apoptotic cell death. Together these data suggest that GSK3 regulates Nrf1 expression and cell survival function in response to stress activation. PMID:23623971

  3. Modulation of NRF2 signaling pathway by nuclear receptors: implications for cancer.

    PubMed

    Namani, Akhileshwar; Li, Yulong; Wang, Xiu Jun; Tang, Xiuwen

    2014-09-01

    Nuclear factor-erythroid 2 p45-related factor 2 (NRF2, also known as Nfe2l2) plays a critical role in regulating cellular defense against electrophilic and oxidative stress by activating the expression of an array of antioxidant response element-dependent genes. On one hand, NRF2 activators have been used in clinical trials for cancer prevention and the treatment of diseases associated with oxidative stress; on the other hand, constitutive activation of NRF2 in many types of tumors contributes to the survival and growth of cancer cells, as well as resistance to anticancer therapy. In this review, we provide an overview of the NRF2 signaling pathway and discuss its role in carcinogenesis. We also introduce the inhibition of NRF2 by nuclear receptors. Further, we address the biological significance of regulation of the NRF2 signaling pathway by nuclear receptors in health and disease. Finally, we discuss the possible impact of NRF2 inhibition by nuclear receptors on cancer therapy. Copyright © 2014 Elsevier B.V. All rights reserved.

  4. Glycogen synthase kinase 3 regulates expression of nuclear factor-erythroid-2 related transcription factor-1 (Nrf1) and inhibits pro-survival function of Nrf1

    DOE Office of Scientific and Technical Information (OSTI.GOV)

    Biswas, Madhurima; Kwong, Erick K.; Park, Eujean

    2013-08-01

    Nuclear factor E2-related factor-1 (Nrf1) is a basic leucine zipper transcription factor that is known to regulate antioxidant and cytoprotective gene expression. It was recently shown that Nrf1 is regulated by SCF–Fbw7 ubiquitin ligase. However our knowledge of upstream signals that targets Nrf1 for degradation by the UPS is not known. We report here that Nrf1 expression is negatively regulated by glycogen synthase kinase 3 (GSK3) in Fbw7-dependent manner. We show that GSK3 interacts with Nrf1 and phosphorylates the Cdc4 phosphodegron domain (CPD) in Nrf1. Mutation of serine residue in the CPD of Nrf1 to alanine (S350A), blocks Nrf1 frommore » phosphorylation by GSK3, and stabilizes Nrf1. Knockdown of Nrf1 and expression of a constitutively active form of GSK3 results in increased apoptosis in neuronal cells in response to ER stress, while expression of the GSK3 phosphorylation resistant S350A–Nrf1 attenuates apoptotic cell death. Together these data suggest that GSK3 regulates Nrf1 expression and cell survival function in response to stress activation. Highlights: • The effect of GSK3 on Nrf1 expression was examined. • GSK3 destabilizes Nrf1 protein via Fbw7 ubiquitin ligase. • GSK3 binds and phosphorylates Nrf1. • Protection from stress-induced apoptosis by Nrf1 is inhibited by GSK3.« less

  5. PML-Nuclear Bodies Regulate the Stability of the Fusion Protein Dendra2-Nrf2 in the Nucleus.

    PubMed

    Burroughs, Andrea Flores; Eluhu, Sylvia; Whalen, Diva; Goodwin, J Shawn; Sakwe, Amos M; Arinze, Ifeanyi J

    2018-05-22

    Nuclear factor erythroid 2-related factor 2 (Nrf2) is a basic leucine-zipper transcription factor essential for cellular responses to oxidative stress. Degradation of Nrf2 in the cytoplasm, mediated by Keap1-Cullin3/RING box1 (Cul3-Rbx1) E3 ubiquitin ligase and the proteasome, is considered the primary pathway controlling the cellular abundance of Nrf2. Although the nucleus has been implicated in the degradation of Nrf2, little information is available on how this compartment participates in degrading Nrf2. Here, we fused the photoconvertible fluorescent protein Dendra2 to Nrf2 and capitalized on the irreversible change in color (green to red) that occurs when Dendra2 undergoes photoconversion to study degradation of Dendra2-Nrf2 in single live cells. Using this approach, we show that the half-life (t1/2) of Dendra2-Nrf2 in the whole cell, under homeostatic conditions, is 35 min. Inhibition of the proteasome with MG-132 or induction of oxidative stress with tert-butylhydroquinone (tBHQ) extended the half-life of Dendra2-Nrf2 by 6- and 28-fold, respectively. By inhibiting nuclear export using Leptomycin B, we provide direct evidence that degradation of Nrf2 also occurs in the nucleus and involves PML-NBs (Promyelocytic Leukemia-nuclear bodies). We further demonstrate that co-expression of Dendra2-Nrf2 and Crimson-PML-I lacking two PML-I sumoylation sites (K65R and K490R) changed the decay rate of Dendra2-Nrf2 in the nucleus and stabilized the nuclear derived Nrf2 levels in whole cells. Altogether, our findings provide direct evidence for degradation of Nrf2 in the nucleus and suggest that modification of Nrf2 in PML nuclear bodies contributes to its degradation in intact cells. © 2018 The Author(s). Published by S. Karger AG, Basel.

  6. Curcumin attenuates insulin resistance in hepatocytes by inducing Nrf2 nuclear translocation.

    PubMed

    Zhao, Shu-Guang; Li, Qiang; Liu, Zhen-Xiong; Wang, Jing-Jie; Wang, Xv-Xia; Qin, Ming; Wen, Qin-Sheng

    2011-01-01

    NF-E2-Related Factor-2 (Nrf2) is a transcription factor that plays a crucial role in the cellular protection against oxidative stress. Curcumin has been reported to induce Nrf2 nuclear translocation and upregulate the expression of numerous reactive oxygen species (ROS) detoxifying and antioxidant genes in hepatocytes. This study was designed to investigate whether curcumin-induced Nrf2 nuclear translocation could reduce ROS-mediated insulin resistance in cultured LO2 hepatocytes. Human LO2 hepatocytes were incubated with curcumine and glucose oxidase (GO) in the presence/absence of wortmannin (a phosphatidyinositol 3-kinase (PI3K) inhibitor), oxidative stress, cellular damage, Nrf2 nuclear translocation and insulin resistance were measured. GO exposure significantly increased intracellular ROS, glutathione (GSH) depletion, malondialdehyde (MDA) formation, and increased activities of cellular lactate dehydrogenase (LDH) and aspartate amino transferase (AST), as well as causing insulin resistance. Curcumin pretreatment significantly attenuated these disturbances in intracellular ROS, liver enzyme activity and significantly antagonized the lipid peroxidation, GSH depletion and insulin resistance induced by GO in LO2 hepatocytes. These effects paralleled Nrf2 nuclear translocation induced by curcumin. Wortmannin partially blocked curcumin-induced Nrf2 nuclear translocation. In addition, wortmannin prevented curcumin-induced improvements in intracellular ROS, MDA formation, GSH depletion, liver enzyme activity and insulin resistance in cultured LO2 hepatocytes. These findings suggest that curcumin could reduce ROS-mediated insulin resistance in hepatocytes, at least in part through nuclear translocation of Nrf2.

  7. [Baicalin increases the antioxidant capacity via promoting the nuclear translocation of NF-E2-related factor 2 (Nrf2) in N2a/APPswe cells].

    PubMed

    Cao, Huimin; Chen, Beibei; Deng, Yushuang; Lu, Xi; Yu, Gang

    2015-12-01

    To investigate the protective effect and related mechanism of baicalin in murine neuroblastoma N2a cells stably expressing human Swedish mutant amyloid precursor protein (APP) (N2a/APPswe cells), a cellular model of Alzheimer' s disease (AD). MTT assay was performed to observe the effect of baicalin (0.1, 0.5, 1, 5, 10, 20) μmol/L on the viability of N2a/APPswe cells. After N2a/APPswe cells were incubated with (1, 5, 10) μmol/L baicalin for 48 hours, xanthine oxidase assay was used to test superoxide dismutase (SOD) activity and thiobarbituric acid method to detect malondialdehyde (MDA) content in each group. Real-time quantitative PCR was applied to determine nuclear factor erythroid 2-related factor 2 (Nrf2) mRNA, and Western blotting to examine protein levels of total Nrf2, nuclear Nrf2 and nuclear factor κB (NF-κB) in N2a/APPswe cells exposed to different doses of baicalin. Immunofluorescence staining was also used to observe the distribution of Nrf2. We found that baicalin pretreatment increased cell viability. Compared with the control group (N2a/wt cells), SOD activity in N2a/APPswe cells significantly decreased, and MDA content significantly increased; but SOD activity was improved and MDA production was inhibited after pretreatment with baicalin, especially with 10 μmol/L bacalin. Both mRNA and total protein expression of Nrf2 were not significantly changed in baicalin treatment group compared with N2a/APPswe group, but the nuclear protein of Nrf2 distinctly increased after treatment with baicalin. In addition, baicalin decreased the level of nuclear NF-κB protein. Furthermore, immunofluorescence staining revealed that baicalin promoted the translocation of Nrf2 to the nucleus. Baicalin has the protection against oxidative stress via activation of Nrf2 in N2a/APPswe cells.

  8. A novel nuclear factor erythroid 2-related factor 2 (Nrf2) activator RS9 attenuates brain injury after ischemia reperfusion in mice.

    PubMed

    Yamauchi, Keita; Nakano, Yusuke; Imai, Takahiko; Takagi, Toshinori; Tsuruma, Kazuhiro; Shimazawa, Masamitsu; Iwama, Toru; Hara, Hideaki

    2016-10-01

    Recanalization of occluded vessels leads to ischemia-reperfusion injury (IRI), with oxidative stress as one of the main causes of injury, despite the fact that recanalization therapy is the most effective treatment for ischemic stroke. The nuclear factor erythroid 2-related factor 2 (Nrf2) is one of the transcription factors which has an essential role in protection against oxidative stress. RS9 is a novel Nrf2 activator obtained from bardoxolone methyl (BARD), an Nrf2 activator that has already been tested in a clinical trial, using a biotransformation technique. RS9 has been reported to lead to higher Nrf2 activation and less cytotoxicity than BARD. In this study, we investigated the effects of RS9 on IRI. Mice were intraperitoneally treated immediately after 2h of transient middle cerebral artery occlusion (MCAO) with a vehicle solution or 0.2mg/kg of RS9. Post-onset treatment of RS9 attenuated the infarct volume and improved neurological deficits 22h after reperfusion. RS9 activated Nrf2 2 and 6h after reperfusion and activated heme oxygenase-1 at 6 and 22h after reperfusion. RS9 also attenuated the phosphorylation of NF-κB p65 2 and 6h after reperfusion. Finally, RS9 improved the survival rate and neurological deficits 7days after MCAO. Our results suggest that the activation of Nrf2 by RS9 has a neuroprotective effect, mediated by attenuating both oxidative stress and neuroinflammation, and that RS9 is an effective therapeutic candidate for the treatment of IRI. Copyright © 2016 IBRO. Published by Elsevier Ltd. All rights reserved.

  9. Trafficking of the transcription factor Nrf2 to promyelocytic leukemia-nuclear bodies: implications for degradation of NRF2 in the nucleus.

    PubMed

    Malloy, Melanie Theodore; McIntosh, Deneshia J; Walters, Treniqka S; Flores, Andrea; Goodwin, J Shawn; Arinze, Ifeanyi J

    2013-05-17

    Ubiquitylation of Nrf2 by the Keap1-Cullin3/RING box1 (Cul3-Rbx1) E3 ubiquitin ligase complex targets Nrf2 for proteasomal degradation in the cytoplasm and is an extensively studied mechanism for regulating the cellular level of Nrf2. Although mechanistic details are lacking, reports abound that Nrf2 can also be degraded in the nucleus. Here, we demonstrate that Nrf2 is a target for sumoylation by both SUMO-1 and SUMO-2. HepG2 cells treated with As2O3, which enhances attachment of SUMO-2/3 to target proteins, increased SUMO-2/3-modification (polysumoylation) of Nrf2. We show that Nrf2 traffics, in part, to promyelocytic leukemia-nuclear bodies (PML-NBs). Cell fractions harboring key components of PML-NBs did not contain biologically active Keap1 but contained modified Nrf2 as well as RING finger protein 4 (RNF4), a poly-SUMO-specific E3 ubiquitin ligase. Overexpression of wild-type RNF4, but not the catalytically inactive mutant, decreased the steady-state levels of Nrf2, measured in the PML-NB-enriched cell fraction. The proteasome inhibitor MG-132 interfered with this decrease, resulting in elevated levels of polysumoylated Nrf2 that was also ubiquitylated. Wild-type RNF4 accelerated the half-life (t½) of Nrf2, measured in PML-NB-enriched cell fractions. These results suggest that RNF4 mediates polyubiquitylation of polysumoylated Nrf2, leading to its subsequent degradation in PML-NBs. Overall, this work identifies Nrf2 as a target for sumoylation and provides a novel mechanism for its degradation in the nucleus, independent of Keap1.

  10. Expression of Nrf2 in neurodegenerative diseases.

    PubMed

    Ramsey, Chenere P; Glass, Charles A; Montgomery, Marshall B; Lindl, Kathryn A; Ritson, Gillian P; Chia, Luis A; Hamilton, Ronald L; Chu, Charleen T; Jordan-Sciutto, Kelly L

    2007-01-01

    In response to oxidative stress, the nuclear factor E2-related factor 2 (Nrf2) transcription factor translocates from the cytoplasm into the nucleus and transactivates expression of genes with antioxidant activity. Despite this cellular mechanism, oxidative damage is abundant in Alzheimer and Parkinson disease (AD and PD). To investigate mechanisms by which Nrf2 activity may be aberrant or insufficient in neurodegenerative conditions, we assessed Nrf2 localization in affected brain regions of AD, Lewy body variant of AD (LBVAD), and PD. By immunohistochemistry, Nrf2 is expressed in both the nucleus and the cytoplasm of neurons in normal hippocampi with predominant expression in the nucleus. In AD and LBVAD, Nrf2 was predominantly cytoplasmic in hippocampal neurons and was not a major component of beta amyloid plaques or neurofibrillary tangles. By immunoblotting, we observed a significant decrease in nuclear Nrf2 levels in AD cases. In contrast, Nrf2 was strongly nuclear in PD nigral neurons but cytoplasmic in substantia nigra of normal, AD, and LBVAD cases. These findings suggest that Nrf2-mediated transcription is not induced in neurons in AD despite the presence of oxidative stress. In PD, nuclear localization of Nrf2 is strongly induced, but this response may be insufficient to protect neurons from degeneration.

  11. Expression of Nrf2 in Neurodegenerative Diseases

    PubMed Central

    Ramsey, Chenere P.; Glass, Charles A.; Montgomery, Marshall B.; Lindl, Kathryn A.; Ritson, Gillian P.; Chia, Luis A.; Hamilton, Ronald L.; Chu, Charleen T.; Jordan-Sciutto, Kelly L.

    2008-01-01

    In response to oxidative stress, the nuclear factor E2-related factor 2 (Nrf2) transcription factor translocates from the cytoplasm into the nucleus and transactivates expression of genes with antioxidant activity. Despite this cellular mechanism, oxidative damage is abundant in Alzheimer and Parkinson disease (AD and PD). To investigate mechanisms by which Nrf2 activity may be aberrant or insufficient in neurodegenerative conditions, we assessed Nrf2 localization in affected brain regions of AD, Lewy body variant of AD (LBVAD), and PD. By immunohistochemistry, Nrf2 is expressed in both the nucleus and the cytoplasm of neurons in normal hippocampi with predominant expression in the nucleus. In AD and LBVAD, Nrf2 was predominantly cytoplasmic in hippocampal neurons and was not a major component of beta amyloid plaques or neurofibrillary tangles. By immunoblotting, we observed a significant decrease in nuclear Nrf2 levels in AD cases. In contrast, Nrf2 was strongly nuclear in PD nigral neurons but cytoplasmic in substantia nigra of normal, AD, and LBVAD cases. These findings suggest that Nrf2-mediated transcription is not induced in neurons in AD despite the presence of oxidative stress. In PD, nuclear localization of Nrf2 is strongly induced, but this response may be insufficient to protect neurons from degeneration. PMID:17204939

  12. The role of Nrf2 transcription factor in viral infection.

    PubMed

    Ramezani, Ali; Nahad, Mehdi Parsa; Faghihloo, Ebrahim

    2018-05-08

    The nuclear factor erythroid 2 related factor 2 (Nrf2) is a major regulator of intracellular inducible defense systems against harmful endogenous and exogenous substances in the body. Under normal conditions Nrf2 is mainly binds to keap1 and located in the cytoplasm. However, in response to oxidative and electrophile stress, Nrf2 translocated to the nucleus and link to anti-oxidant response elements to induce the transcription of cytoprotective genes. Most viruses cause oxidative stress and increase the activity of radicals and reactive oxygen species (ROS), subsequently, the cellular protection system activates the Nrf2 and increases the expression of cytoprotective genes. However, in some cases, the activation of Nrf2 is not ROS-dependent, and is carried out directly via the ROS-independent pathway. Many viruses cause the activation of Nrf2, which is involved in the pathogenesis and the progression of the virus infection and even in its chronic form. However, some viruses inhibit the activation of Nrf2, in which case the virus also benefits of this mechanism to maintain the homeostasis of the cell. However, the challenge between the Nrf2/ARE signaling pathway of and viral infections is unknown in some cases, and in order to know more details in this regard, a more detailed seems necessary. © 2018 Wiley Periodicals, Inc.

  13. Insulin Inhibits Nrf2 Gene Expression via Heterogeneous Nuclear Ribonucleoprotein F/K in Diabetic Mice

    PubMed Central

    Ghosh, Anindya; Abdo, Shaaban; Zhao, Shuiling; Wu, Chin-Han; Shi, Yixuan; Lo, Chao-Sheng; Chenier, Isabelle; Alquier, Thierry; Filep, Janos G.; Ingelfinger, Julie R.; Zhang, Shao-Ling

    2017-01-01

    Oxidative stress induces endogenous antioxidants via nuclear factor erythroid 2–related factor 2 (Nrf2), potentially preventing tissue injury. We investigated whether insulin affects renal Nrf2 expression in type 1 diabetes (T1D) and studied its underlying mechanism. Insulin normalized hyperglycemia, hypertension, oxidative stress, and renal injury; inhibited renal Nrf2 and angiotensinogen (Agt) gene expression; and upregulated heterogeneous nuclear ribonucleoprotein F and K (hnRNP F and hnRNP K) expression in Akita mice with T1D. In immortalized rat renal proximal tubular cells, insulin suppressed Nrf2 and Agt but stimulated hnRNP F and hnRNP K gene transcription in high glucose via p44/42 mitogen-activated protein kinase signaling. Transfection with small interfering RNAs of p44/42 MAPK, hnRNP F, or hnRNP K blocked insulin inhibition of Nrf2 gene transcription. Insulin curbed Nrf2 promoter activity via a specific DNA-responsive element that binds hnRNP F/K, and hnRNP F/K overexpression curtailed Nrf2 promoter activity. In hyperinsulinemic-euglycemic mice, renal Nrf2 and Agt expression was downregulated, whereas hnRNP F/K expression was upregulated. Thus, the beneficial actions of insulin in diabetic nephropathy appear to be mediated, in part, by suppressing renal Nrf2 and Agt gene transcription and preventing Nrf2 stimulation of Agt expression via hnRNP F/K. These findings identify hnRNP F/K and Nrf2 as potential therapeutic targets in diabetes. PMID:28324005

  14. Non-covalent Small-Molecule Kelch-like ECH-Associated Protein 1-Nuclear Factor Erythroid 2-Related Factor 2 (Keap1-Nrf2) Inhibitors and Their Potential for Targeting Central Nervous System Diseases.

    PubMed

    Pallesen, Jakob S; Tran, Kim T; Bach, Anders

    2018-05-29

    The transcription factor nuclear factor erythroid 2-related factor 2 (Nrf2) has a protective effect against oxidative stress and plays a major role in inflammation and central nervous system (CNS) diseases. Inhibition of the protein-protein interaction (PPI) between Nrf2 and its repressor protein, Kelch-like ECH-associated protein 1 (Keap1), leads to translocation of Nrf2 from the cytosol to the nucleus and expression of detoxifying antioxidant enzymes. To date, several non-covalent small-molecule Keap1-Nrf2 inhibitors have been identified; however, many of them contain carboxylic acids and are rather large in size, which likely prevents or decreases CNS permeability. This Perspective describes current small-molecule Keap1-Nrf2 inhibitors with experimental evidence for the ability to inhibit the Keap1-Nrf2 interaction by binding to Keap1 in a non-covalent manner. Binding data, biostructural studies, and biological activity are summarized for the inhibitors, and their potential as CNS tool compounds is discussed by analyzing physicochemical properties, including CNS multiparameter optimization (MPO) scoring algorithms. Finally, several strategies for identifying CNS-targeting Keap1 inhibitors are described.

  15. Molecular Evolution of the Nuclear Factor (Erythroid-Derived 2)-Like 2 Gene Nrf2 in Old World Fruit Bats (Chiroptera: Pteropodidae).

    PubMed

    Yin, Qiuyuan; Zhu, Lei; Liu, Di; Irwin, David M; Zhang, Shuyi; Pan, Yi-Hsuan

    2016-01-01

    Mammals developed antioxidant systems to defend against oxidative damage in their daily life. Enzymatic antioxidants and low molecular weight antioxidants (LMWAs) constitute major parts of the antioxidant systems. Nuclear factor (erythroid-derived 2)-like 2 (Nrf2, encoded by the Nrf2 gene) is a central transcriptional regulator, regulating transcription, of many antioxidant enzymes. Frugivorous bats eat large amounts of fruits that contain high levels of LMWAs such as vitamin C, thus, a reliance on LMWAs might greatly reduce the need for antioxidant enzymes in comparison to insectivorous bats. Therefore, it is possible that frugivorous bats have a reduced need for Nrf2 function due to their substantial intake of diet-antioxidants. To test whether the Nrf2 gene has undergone relaxed evolution in fruit-eating bats, we obtained Nrf2 sequences from 16 species of bats, including four Old World fruit bats (Pteropodidae) and one New World fruit bat (Phyllostomidae). Our molecular evolutionary analyses revealed changes in the selection pressure acting on Nrf2 gene and identified seven specific amino acid substitutions that occurred on the ancestral lineage leading to Old World fruit bats. Biochemical experiments were conducted to examine Nrf2 in Old World fruit bats and showed that the amount of catalase, which is regulated by Nrf2, was significantly lower in the brain, heart and liver of Old World fruit bats despite higher levels of Nrf2 protein in Old World fruit bats. Computational predictions suggest that three of these seven amino acid replacements might be deleterious to Nrf2 function. Therefore, the results suggest that Nrf2 gene might have experienced relaxed constraint in Old World fruit bats, however, we cannot rule out the possibility of positive selection. Our study provides the first data on the molecular adaptation of Nrf2 gene in frugivorous bats in compensation to the increased levels of LWMAs from their fruit-diet.

  16. Molecular Evolution of the Nuclear Factor (Erythroid-Derived 2)-Like 2 Gene Nrf2 in Old World Fruit Bats (Chiroptera: Pteropodidae)

    PubMed Central

    Liu, Di; Irwin, David M.; Zhang, Shuyi; Pan, Yi-Hsuan

    2016-01-01

    Mammals developed antioxidant systems to defend against oxidative damage in their daily life. Enzymatic antioxidants and low molecular weight antioxidants (LMWAs) constitute major parts of the antioxidant systems. Nuclear factor (erythroid-derived 2)-like 2 (Nrf2, encoded by the Nrf2 gene) is a central transcriptional regulator, regulating transcription, of many antioxidant enzymes. Frugivorous bats eat large amounts of fruits that contain high levels of LMWAs such as vitamin C, thus, a reliance on LMWAs might greatly reduce the need for antioxidant enzymes in comparison to insectivorous bats. Therefore, it is possible that frugivorous bats have a reduced need for Nrf2 function due to their substantial intake of diet-antioxidants. To test whether the Nrf2 gene has undergone relaxed evolution in fruit-eating bats, we obtained Nrf2 sequences from 16 species of bats, including four Old World fruit bats (Pteropodidae) and one New World fruit bat (Phyllostomidae). Our molecular evolutionary analyses revealed changes in the selection pressure acting on Nrf2 gene and identified seven specific amino acid substitutions that occurred on the ancestral lineage leading to Old World fruit bats. Biochemical experiments were conducted to examine Nrf2 in Old World fruit bats and showed that the amount of catalase, which is regulated by Nrf2, was significantly lower in the brain, heart and liver of Old World fruit bats despite higher levels of Nrf2 protein in Old World fruit bats. Computational predictions suggest that three of these seven amino acid replacements might be deleterious to Nrf2 function. Therefore, the results suggest that Nrf2 gene might have experienced relaxed constraint in Old World fruit bats, however, we cannot rule out the possibility of positive selection. Our study provides the first data on the molecular adaptation of Nrf2 gene in frugivorous bats in compensation to the increased levels of LWMAs from their fruit-diet. PMID:26735303

  17. Identifying panaxynol, a natural activator of nuclear factor erythroid-2 related factor 2 (Nrf2) from American ginseng as a suppressor of inflamed macrophage-induced cardiomyocyte hypertrophy

    PubMed Central

    Qu, Chen; Li, Bin; Lai, Yimu; Li, Hechu; Windust, Anthony; Hofseth, Lorne J.; Nagarkatti, Mitzi; Nagarkatti, Prakash; Wang, Xing Li; Tang, Dongqi; Janicki, Joseph S.; Tian, Xingsong; Cui, Taixing

    2015-01-01

    Ethnopharmacological relevance American ginseng is capable of ameliorating cardiac dysfunction and activating Nrf2, a master regulator of antioxidant defense, in the heart. This study was designed to isolate compounds from American ginseng and to determine those responsible for the Nrf2-mediated resolution of inflamed macrophage-induced cardiomyocyte hypertrophy. Materials and methods A standardized crude extract of American ginseng was supplied by the National Research Council of Canada, Institute for National Measurement Standards. A bioassay-based fractionization of American ginseng was performed to identify the putative substances which could activate Nrf2-mediated suppression of pro-inflammatory cytokine expression in macrophages and macrophage-mediated pro-hypertrophic growth in cardiomyocytes. Results A hexane fraction of an anti-inflammatory crude extract of American ginseng was found to be most effective in suppressing the inflammatory responses in macrophages. Preparative, reverse-phase HPLC and a comparative analysis by analytical scale LC–UV/MS revealed the hexane fraction contains predominantly C17 polyacetylenes and linolenic acid. Panaxynol, one of the major polyacetylenes, was found to be a potent Nrf2 activator. Panaxynol posttranscriptionally activated Nrf2 by inhibiting Kelch-like ECH-associated protein (Keap) 1-mediated degradation without affecting the binding of Keap1 and Nrf2. Moreover, panaxynol suppressed a selected set of cytokine expression via the activation of Nrf2 while minimally regulating nuclear factor-kappa B (NF-κB)-mediated cytokine expression in macrophages. It also dramatically inhibited the inflamed macrophage-mediated cardiomyocyte death and hypertrophy by activating Nrf2 in macrophages. Conclusions These results demonstrate that American ginseng-derived panaxynol is a specific Nrf2 activator and panaxynol-activated Nrf2 signaling is at least partly responsible for American ginseng-induced health benefit in the heart. PMID

  18. Differential regulation of innate immune cytokine production through pharmacological activation of Nuclear Factor-Erythroid-2-Related Factor 2 (NRF2) in burn patient immune cells and monocytes

    PubMed Central

    Stepp, Wesley; Sjeklocha, Lucas; Long, Clayton; Riley, Caitlin; Callahan, James; Sanchez, Yolanda; Gough, Peter; Knowlin, Laquanda; van Duin, David; Ortiz-Pujols, Shiara; Jones, Samuel; Maile, Robert; Hong, Zhi; Berger, Scott; Cairns, Bruce

    2017-01-01

    Burn patients suffer from immunological dysfunction for which there are currently no successful interventions. Similar to previous observations, we find that burn shock patients (≥15% Total Burn Surface Area (TBSA) injury) have elevated levels of the innate immune cytokines Interleukin-6 (IL-6) and Monocyte Chemoattractant Protein-1 (MCP-1)/CC-motif Chemokine Ligand 2(CCL2) early after hospital admission (0–48 Hours Post-hospital Admission (HPA). Functional immune assays with patient Peripheral Blood Mononuclear Cells (PBMCs) revealed that burn shock patients (≥15% TBSA) produced elevated levels of MCP-1/CCL2 after innate immune stimulation ex vivo relative to mild burn patients. Interestingly, treatment of patient PBMCs with the Nuclear Factor-Erythroid-2-Related Factor 2 (NRF2) agonist, CDDO-Me(bardoxolone methyl), reduced MCP-1 production but not IL-6 or Interleukin-10 (IL-10) secretion. In enriched monocytes from healthy donors, CDDO-Me(bardoxolone methyl) also reduced LPS-induced MCP1/CCL2 production but did not alter IL-6 or IL-10 secretion. Similar immunomodulatory effects were observed with Compound 7, which activates the NRF2 pathway through a different and non-covalent Mechanism Of Action (MOA). Hence, our findings with CDDO-Me(bardoxolone methyl) and Compound 7 are likely to reflect a generalizable aspect of NRF2 activation. These observed effects were not specific to LPS-induced immune responses, as NRF2 activation also reduced MCP-1/CCL2 production after stimulation with IL-6. Pharmacological NRF2 activation reduced Mcp-1/Ccl2 transcript accumulation without inhibiting either Il-6 or Il-10 transcript levels. Hence, we describe a novel aspect of NRF2 activation that may contribute to the beneficial effects of NRF2 agonists during disease. Our work also demonstrates that the NRF2 pathway is retained and can be modulated to regulate important immunomodulatory functions in burn patient immune cells. PMID:28886135

  19. Differential regulation of innate immune cytokine production through pharmacological activation of Nuclear Factor-Erythroid-2-Related Factor 2 (NRF2) in burn patient immune cells and monocytes.

    PubMed

    Eitas, Timothy K; Stepp, Wesley H; Sjeklocha, Lucas; Long, Clayton V; Riley, Caitlin; Callahan, James; Sanchez, Yolanda; Gough, Peter; Knowlin, Laquanda; van Duin, David; Ortiz-Pujols, Shiara; Jones, Samuel W; Maile, Robert; Hong, Zhi; Berger, Scott; Cairns, Bruce A

    2017-01-01

    Burn patients suffer from immunological dysfunction for which there are currently no successful interventions. Similar to previous observations, we find that burn shock patients (≥15% Total Burn Surface Area (TBSA) injury) have elevated levels of the innate immune cytokines Interleukin-6 (IL-6) and Monocyte Chemoattractant Protein-1 (MCP-1)/CC-motif Chemokine Ligand 2(CCL2) early after hospital admission (0-48 Hours Post-hospital Admission (HPA). Functional immune assays with patient Peripheral Blood Mononuclear Cells (PBMCs) revealed that burn shock patients (≥15% TBSA) produced elevated levels of MCP-1/CCL2 after innate immune stimulation ex vivo relative to mild burn patients. Interestingly, treatment of patient PBMCs with the Nuclear Factor-Erythroid-2-Related Factor 2 (NRF2) agonist, CDDO-Me(bardoxolone methyl), reduced MCP-1 production but not IL-6 or Interleukin-10 (IL-10) secretion. In enriched monocytes from healthy donors, CDDO-Me(bardoxolone methyl) also reduced LPS-induced MCP1/CCL2 production but did not alter IL-6 or IL-10 secretion. Similar immunomodulatory effects were observed with Compound 7, which activates the NRF2 pathway through a different and non-covalent Mechanism Of Action (MOA). Hence, our findings with CDDO-Me(bardoxolone methyl) and Compound 7 are likely to reflect a generalizable aspect of NRF2 activation. These observed effects were not specific to LPS-induced immune responses, as NRF2 activation also reduced MCP-1/CCL2 production after stimulation with IL-6. Pharmacological NRF2 activation reduced Mcp-1/Ccl2 transcript accumulation without inhibiting either Il-6 or Il-10 transcript levels. Hence, we describe a novel aspect of NRF2 activation that may contribute to the beneficial effects of NRF2 agonists during disease. Our work also demonstrates that the NRF2 pathway is retained and can be modulated to regulate important immunomodulatory functions in burn patient immune cells.

  20. Nrf2: bane or blessing in cancer?

    PubMed

    Xiang, MingJun; Namani, Akhileshwar; Wu, ShiJun; Wang, XiaoLi

    2014-08-01

    The Kelch-like ECH-associated protein 1 (Keap1)-nuclear factor-E2-related factor 2 (Nrf2)-antioxidant response element pathway serves a major function in endogenous cytoprotection in normal cells. Nrf2 is a transcription factor that mainly regulates the expression of a wide array of genes that produce the antioxidants and other proteins responsible for the detoxification of xenobiotics and reactive oxygen species. Nrf2 mediates the chemoprevention of cancer in normal cells. Growing body of evidence suggests that Nrf2 is not only involved in the chemoprevention of normal cells but also promotes the growth of cancer cells. However, the mechanism underlying the function of Nrf2 in oncogenesis and tumor protection in cancer cells remains unclear and thus requires further study. This review aims to rationalize the existing functions of Nrf2 in chemoprevention and tumorigenesis, as well as the somatic mutations of Nrf2 and Keap1 in cancer and Nrf2 cross talk with miRNAs. This review also discusses the future challenges in Nrf2 research.

  1. Canonical and non-canonical mechanisms of Nrf2 activation.

    PubMed

    Silva-Islas, Carlos Alfredo; Maldonado, Perla D

    2018-06-15

    Nuclear Factor Erythroid 2-related factor 2 (Nrf2) is a transcription factor that regulates the expression of genes involved in the metabolism, immune response, cellular proliferation, and other processes; however, the attention has been focused on the study of its ability to induce the expression of proteins involved in the antioxidant defense. Nrf2 is mainly regulated by Kelch-like ECH-associated protein 1 (Keap1), an adapter substrate of Cullin 3 (Cul3) ubiquitin E3 ligase complex. Keap1 represses Nrf2 activity in the cytoplasm by its sequestering, ubiquitination and proteosomal degradation. Nrf2 activation, through the canonical mechanism, is carried out by electrophilic compounds and oxidative stress where some cysteine residues in Keap1 are oxidized, resulting in a decrease in Nrf2 ubiquitination and an increase in its nuclear translocation and activation. In the nucleus, Nrf2 induces a variety of genes involved in the antioxidant defense. Recently a new mechanism of Nrf2 activation has been described, called the non-canonical pathway, where proteins such as p62, p21, dipeptidyl peptidase III (DPP3), wilms tumor gene on X chromosome (WTX) and others are able to disrupt the Nrf2-Keap1 complex, by direct interaction with Keap1 decreasing Nrf2 ubiquitination and increasing its nuclear translocation and activation. In this review, the regulatory mechanisms involved in both canonical and non-canonical Nrf2 activation are discussed. Copyright © 2018. Published by Elsevier Ltd.

  2. Mining a human transcriptome database for Nrf2 modulators

    EPA Science Inventory

    Nuclear factor erythroid-2 related factor 2 (Nrf2) is a key transcription factor important in the protection against oxidative stress. We developed computational procedures to enable the identification of chemical, genetic and environmental modulators of Nrf2 in a large database ...

  3. Nrf2 protects against airway disorders

    DOE Office of Scientific and Technical Information (OSTI.GOV)

    Cho, Hye-Youn, E-mail: cho2@niehs.nih.go; Kleeberger, Steven R.

    Nuclear factor-erythroid 2 related factor 2 (Nrf2) is a ubiquitous master transcription factor that regulates antioxidant response elements (AREs)-mediated expression of antioxidant enzyme and cytoprotective proteins. In the unstressed condition, Kelch-like ECH-associated protein 1 (Keap1) suppresses cellular Nrf2 in cytoplasm and drives its proteasomal degradation. Nrf2 can be activated by diverse stimuli including oxidants, pro-oxidants, antioxidants, and chemopreventive agents. Nrf2 induces cellular rescue pathways against oxidative injury, abnormal inflammatory and immune responses, apoptosis, and carcinogenesis. Application of Nrf2 germ-line mutant mice has identified an extensive range of protective roles for Nrf2 in experimental models of human disorders in the liver,more » gastrointestinal tract, airway, kidney, brain, circulation, and immune or nerve system. In the lung, lack of Nrf2 exacerbated toxicity caused by multiple oxidative insults including supplemental respiratory therapy (e.g., hyperoxia, mechanical ventilation), cigarette smoke, allergen, virus, bacterial endotoxin and other inflammatory agents (e.g., carrageenin), environmental pollution (e.g., particles), and a fibrotic agent bleomycin. Microarray analyses and bioinformatic studies elucidated functional AREs and Nrf2-directed genes that are critical components of signaling mechanisms in pulmonary protection by Nrf2. Association of loss of function with promoter polymorphisms in NRF2 or somatic and epigenetic mutations in KEAP1 and NRF2 has been found in cohorts of patients with acute lung injury/acute respiratory distress syndrome or lung cancer, which further supports the role for NRF2 in these lung diseases. In the current review, we address the role of Nrf2 in airways based on emerging evidence from experimental oxidative disease models and human studies.« less

  4. Nuclear respiratory factor 2 regulates the expression of the same NMDA receptor subunit genes as NRF-1: both factors act by a concurrent and parallel mechanism to couple energy metabolism and synaptic transmission.

    PubMed

    Priya, Anusha; Johar, Kaid; Wong-Riley, Margaret T T

    2013-01-01

    Neuronal activity and energy metabolism are tightly coupled processes. Previously, we found that nuclear respiratory factor 1 (NRF-1) transcriptionally co-regulates energy metabolism and neuronal activity by regulating all 13 subunits of the critical energy generating enzyme, cytochrome c oxidase (COX), as well as N-methyl-d-aspartate (NMDA) receptor subunits 1 and 2B, GluN1 (Grin1) and GluN2B (Grin2b). We also found that another transcription factor, nuclear respiratory factor 2 (NRF-2 or GA-binding protein) regulates all subunits of COX as well. The goal of the present study was to test our hypothesis that NRF-2 also regulates specific subunits of NMDA receptors, and that it functions with NRF-1 via one of three mechanisms: complementary, concurrent and parallel, or a combination of complementary and concurrent/parallel. By means of multiple approaches, including in silico analysis, electrophoretic mobility shift and supershift assays, in vivo chromatin immunoprecipitation of mouse neuroblastoma cells and rat visual cortical tissue, promoter mutations, real-time quantitative PCR, and western blot analysis, NRF-2 was found to functionally regulate Grin1 and Grin2b genes, but not any other NMDA subunit genes. Grin1 and Grin2b transcripts were up-regulated by depolarizing KCl, but silencing of NRF-2 prevented this up-regulation. On the other hand, over-expression of NRF-2 rescued the down-regulation of these subunits by the impulse blocker TTX. NRF-2 binding sites on Grin1 and Grin2b are conserved among species. Our data indicate that NRF-2 and NRF-1 operate in a concurrent and parallel manner in mediating the tight coupling between energy metabolism and neuronal activity at the molecular level. Copyright © 2012 Elsevier B.V. All rights reserved.

  5. Role of nuclear factor-erythroid 2-related factor 2 (Nrf2) in the transcriptional regulation of brain ABC transporters during acute acetaminophen (APAP) intoxication in mice.

    PubMed

    Ghanem, Carolina I; Rudraiah, Swetha; Bataille, Amy M; Vigo, María B; Goedken, Michael J; Manautou, José E

    2015-04-01

    Changes in expression of liver ABC transporters have been described during acute APAP intoxication. However, the effect of APAP on brain ABC transporters is poorly understood. The aim of this study was to evaluate the effect of APAP on brain ABC transporters expression and the role of the oxidative stress sensor Nrf2. Male C57BL/6J mice were administered APAP (400mg/kg) for analysis of brain mRNA and protein expression of Mrp1-6, Bcrp and P-gp. The results show induction of P-gp, Mrp2 and Mrp4 proteins, with no changes in Bcrp, Mrp1 or Mrp5-6. The protein values were accompanied by corresponding changes in mRNA levels. Additionally, brain Nrf2 nuclear translocation and expression of two Nrf2 target genes, quinone oxidoreductase 1 (Nqo1) and Hemoxygenase 1 (Ho-1), was evaluated at 6, 12 and 24h after APAP treatment. Nrf2 nuclear content increased by 58% at 12h after APAP along with significant increments in mRNA and protein expression of Nqo1 and Ho-1. Furthermore, APAP treated Nrf2 knockout mice did not increase mRNA or protein expression of Mrp2 and Mrp4 as observed in wildtypes. In contrast, P-gp induction by APAP was observed in both genotypes. In conclusion, acute APAP intoxication induces protein expression of brain P-gp, Mrp2 and Mrp4. This study also suggests that brain changes in Mrp2 and Mrp4 expression may be due to in situ Nrf2 activation by APAP, while P-gp induction is independent of Nrf2 function. The functional consequences of these changes in brain ABC transporters by APAP deserve further attention. Copyright © 2015 Elsevier Inc. All rights reserved.

  6. L-2-Oxothiazolidine-4-Carboxylic Acid or α-Lipoic Acid Attenuates Airway Remodeling: Involvement of Nuclear Factor-κB (NF-κB), Nuclear Factor Erythroid 2p45-Related Factor-2 (Nrf2), and Hypoxia-Inducible Factor (HIF)

    PubMed Central

    Park, Seoung Ju; Lee, Kyung Sun; Lee, Su Jeong; Kim, So Ri; Park, Seung Yong; Jeon, Myoung Shin; Lee, Heung Bum; Lee, Yong Chul

    2012-01-01

    Reactive oxygen species (ROS) play a crucial role in the pathogenesis of acute and chronic respiratory diseases. Antioxidants have been found to ameliorate airway inflammation and hyperresponsiveness in animal models employing short-term exposure to allergen. However, little data are available on the effect of antioxidants on airway remodeling and signaling pathways in chronic asthma. In the present study, we used a long-term exposure murine model of allergic airway disease to evaluate the effects of an antioxidant, L-2-oxothiazolidine-4-carboxylic acid (OTC) or α-lipoic acid (LA) on airway remodeling, focusing on the ROS-related hypoxia-inducible signaling. Long-term challenge of ovalbumin (OVA) increased ROS production, airway inflammation, and airway hyperresponsiveness, and developed features of airway remodeling such as excessive mucus secretion, subepithelial fibrosis, and thickening of the peribronchial smooth muscle layer. Administration of OTC or LA reduced these features of asthma, including airway remodeling, which was accompanied by suppression of transforming growth factor-β1, vascular endothelial growth factor, and T-helper 2 cytokines. In addition, OVA-induced activation of nuclear factor-κB (NF-κB), nuclear factor erythroid 2p45-related factor-2 (Nrf2), hypoxia-inducible factor (HIF)-1α, and HIF-2α was reduced by OTC or LA. Our results also showed that OTC or LA down-regulated phosphoinositide 3-kinase activity and decreased phosphorylation of p38 mitogen-activated protein kinase but not extracellular signal-regulated kinase 1/2 or c-Jun N-terminal kinase. These findings demonstrate that OTC and LA can inhibit activation of NF-κB, Nrf2, and HIF, leading to attenuate allergen-induced airway remodeling. PMID:22942681

  7. Glycosylation enables aesculin to activate Nrf2.

    PubMed

    Kim, Kyun Ha; Park, Hyunsu; Park, Hee Jin; Choi, Kyoung-Hwa; Sadikot, Ruxana T; Cha, Jaeho; Joo, Myungsoo

    2016-07-15

    Since aesculin, 6,7-dihydroxycoumarin-6-O-β-glucopyranoside, suppresses inflammation, we asked whether its anti-inflammatory activity is associated with the activation of nuclear factor-E2-related factor 2 (Nrf2), a key anti-inflammatory factor. Our results, however, show that aesculin marginally activated Nrf2. Since glycosylation can enhance the function of a compound, we then asked whether adding a glucose makes aesculin activate Nrf2. Our results show that the glycosylated aesculin, 3-O-β-d-glycosyl aesculin, robustly activated Nrf2, inducing the expression of Nrf2-dependent genes, such as heme oxygenase-1, glutamate-cysteine ligase catalytic subunit, and NAD(P)H quinone oxidoreductase 1 in macrophages. Mechanistically, 3-O-β-d-glycosyl aesculin suppressed ubiquitination of Nrf2, retarding degradation of Nrf2. Unlike aesculin, 3-O-β-d-glycosyl aesculin significantly suppressed neutrophilic lung inflammation, a hallmark of acute lung injury (ALI), in mice, which was not recapitulated in Nrf2 knockout mice, suggesting that the anti-inflammatory function of the compound largely acts through Nrf2. In a mouse model of sepsis, a major cause of ALI, 3-O-β-d-glycosyl aesculin significantly enhanced the survival of mice, compared with aesculin. Together, these results show that glycosylation could confer the ability to activate Nrf2 on aesculin, enhancing the anti-inflammatory function of aesculin. These results suggest that glycosylation can be a way to improve or alter the function of aesculin.

  8. The trypanocidal benznidazole promotes adaptive response to oxidative injury: Involvement of the nuclear factor-erythroid 2-related factor-2 (Nrf2) and multidrug resistance associated protein 2 (MRP2)

    DOE Office of Scientific and Technical Information (OSTI.GOV)

    Rigalli, Juan Pablo

    Oxidative stress is a frequent cause underlying drug-induced hepatotoxicity. Benznidazole (BZL) is the only trypanocidal agent available for treatment of Chagas disease in endemic areas. Its use is associated with side effects, including increases in biomarkers of hepatotoxicity. However, BZL potential to cause oxidative stress has been poorly investigated. Here, we evaluated the effect of a pharmacologically relevant BZL concentration (200 μM) at different time points on redox status and the counteracting mechanisms in the human hepatic cell line HepG2. BZL increased reactive oxygen species (ROS) after 1 and 3 h of exposure, returning to normality at 24 h. Additionally,more » BZL increased glutathione peroxidase activity at 12 h and the oxidized glutathione/total glutathione (GSSG/GSSG + GSH) ratio that reached a peak at 24 h. Thus, an enhanced detoxification of peroxide and GSSG formation could account for ROS normalization. GSSG/GSSG + GSH returned to control values at 48 h. Expression of the multidrug resistance-associated protein 2 (MRP2) and GSSG efflux via MRP2 were induced by BZL at 24 and 48 h, explaining normalization of GSSG/GSSG + GSH. BZL activated the nuclear erythroid 2-related factor 2 (Nrf2), already shown to modulate MRP2 expression in response to oxidative stress. Nrf2 participation was confirmed using Nrf2-knockout mice in which MRP2 mRNA expression was not affected by BZL. In summary, we demonstrated a ROS increase by BZL in HepG2 cells and a glutathione peroxidase- and MRP2 driven counteracting mechanism, being Nrf2 a key modulator of this response. Our results could explain hepatic alterations associated with BZL therapy. - Highlights: • BZL triggers a redox imbalance in the human hepatic cell line HepG2. • Concomitantly BZL triggers compensatory mechanisms to alleviate the redox injury. • Response mechanisms comprise an enhanced glutathione peroxidase and MRP2 activity. • Transcription factor Nrf2 plays a key role orchestrating

  9. Low-dose gamma-ray irradiation induces translocation of Nrf2 into nuclear in mouse macrophage RAW264.7 cells.

    PubMed

    Tsukimoto, Mitsutoshi; Tamaishi, Nana; Homma, Takujiro; Kojima, Shuji

    2010-01-01

    The transcription factor nuclear erythroid-derived 2-related factor 2 (Nrf2) regulates expression of genes encoding antioxidant proteins involved in cellular redox homeostasis, while gamma-ray irradiation is known to induce reactive oxygen species in vivo. Although activation of Nrf2 by various stresses has been studied, it has not yet been determined whether ionizing irradiation induces activation of Nrf2. Therefore, we investigated activation of Nrf2 in response to gamma-irradiation in mouse macrophage RAW264.7 cells. Irradiation of cells with gamma-rays induced an increase of Nrf2 expression. Even 0.1 Gy of gamma-irradiation induced a translocation of Nrf2 from cytoplasm to the nucleus, indicating the activation of Nrf2 by low-dose irradiation. Expression of heme oxygenase-1, which is regulated by Nrf2, was also increased at 24 h after irradiation with more than 0.1 Gy of gamma-rays. Furthermore, the activation of Nrf2 was suppressed by U0126, which is an inhibitor of the extracellular signal regulated protein kinase 1/2 (ERK1/2) pathway, suggesting involvement of ERK1/2-dependent pathway in the irradiation-induced activation of Nrf2. Our results indicate that low-dose gamma-irradiation induces activation of Nrf2 through ERK1/2-dependent pathways.

  10. Increased Energy Expenditure, Ucp1 Expression, and Resistance to Diet-induced Obesity in Mice Lacking Nuclear Factor-Erythroid-2-related Transcription Factor-2 (Nrf2).

    PubMed

    Schneider, Kevin; Valdez, Joshua; Nguyen, Janice; Vawter, Marquis; Galke, Brandi; Kurtz, Theodore W; Chan, Jefferson Y

    2016-04-01

    The NRF2 (also known as NFE2L2) transcription factor is a critical regulator of genes involved in defense against oxidative stress. Previous studies suggest thatNrf2plays a role in adipogenesisin vitro, and deletion of theNrf2gene protects against diet-induced obesity in mice. Here, we demonstrate that resistance to diet-induced obesity inNrf2(-/-)mice is associated with a 20-30% increase in energy expenditure. Analysis of bioenergetics revealed thatNrf2(-/-)white adipose tissues exhibit greater oxygen consumption. White adipose tissue showed a >2-fold increase inUcp1gene expression. Oxygen consumption is also increased nearly 2.5-fold inNrf2-deficient fibroblasts. Oxidative stress induced by glucose oxidase resulted in increasedUcp1expression. Conversely, antioxidant chemicals (such asN-acetylcysteine and Mn(III)tetrakis(4-benzoic acid)porphyrin chloride) and SB203580 (a known suppressor ofUcp1expression) decreasedUcp1and oxygen consumption inNrf2-deficient fibroblasts. These findings suggest that increasing oxidative stress by limitingNrf2function in white adipocytes may be a novel means to modulate energy balance as a treatment of obesity and related clinical disorders. © 2016 by The American Society for Biochemistry and Molecular Biology, Inc.

  11. Role of Nuclear Factor Erythroid 2-Related Factor 2 in Diabetic Nephropathy

    PubMed Central

    Min, Xu; Xu, Xiaohong

    2017-01-01

    Diabetic nephropathy (DN) is manifested as increased urinary protein level, decreased glomerular filtration rate, and final renal dysfunction. DN is the leading cause of end-stage renal disease worldwide and causes a huge societal healthcare burden. Since satisfied treatments are still limited, exploring new strategies for the treatment of this disease is urgently needed. Oxidative stress takes part in the initiation and development of DN. In addition, nuclear factor erythroid 2-related factor 2 (Nrf2) plays a key role in the cellular response to oxidative stress. Thus, activation of Nrf2 seems to be a new choice for the treatment of DN. In current review, we discussed and summarized the therapeutic effects of Nrf2 activation on DN from both basic and clinical studies. PMID:28512642

  12. Pyrrolidine dithiocarbamate activates the Nrf2 pathway in astrocytes.

    PubMed

    Liddell, Jeffrey R; Lehtonen, Sarka; Duncan, Clare; Keksa-Goldsteine, Velta; Levonen, Anna-Liisa; Goldsteins, Gundars; Malm, Tarja; White, Anthony R; Koistinaho, Jari; Kanninen, Katja M

    2016-02-26

    Endogenous defense against oxidative stress is controlled by nuclear factor erythroid 2-related factor 2 (Nrf2). The normal compensatory mechanisms to combat oxidative stress appear to be insufficient to protect against the prolonged exposure to reactive oxygen species during disease. Counterbalancing the effects of oxidative stress by up-regulation of Nrf2 signaling has been shown to be effective in various disease models where oxidative stress is implicated, including Alzheimer's disease. Stimulation of Nrf2 signaling by small-molecule activators is an appealing strategy to up-regulate the endogenous defense mechanisms of cells. Here, we investigate Nrf2 induction by the metal chelator and known nuclear factor-κB inhibitor pyrrolidine dithiocarbamate (PDTC) in cultured astrocytes and neurons, and mouse brain. Nrf2 induction is further examined in cultures co-treated with PDTC and kinase inhibitors or amyloid-beta, and in Nrf2-deficient cultures. We show that PDTC is a potent inducer of Nrf2 signaling specifically in astrocytes and demonstrate the critical role of Nrf2 in PDTC-mediated protection against oxidative stress. This induction appears to be regulated by both Keap1 and glycogen synthase kinase 3β. Furthermore, the presence of amyloid-beta magnifies PDTC-mediated induction of endogenous protective mechanisms, therefore suggesting that PDTC may be an effective Nrf2 inducer in the context of Alzheimer's disease. Finally, we show that PDTC increases brain copper content and glial expression of heme oxygenase-1, and decreases lipid peroxidation in vivo, promoting a more antioxidative environment. PDTC activates Nrf2 and its antioxidative targets in astrocytes but not neurons. These effects may contribute to the neuroprotection observed for PDTC in models of Alzheimer's disease.

  13. Transcription Factor NRF2 as a Therapeutic Target for Chronic Diseases: A Systems Medicine Approach.

    PubMed

    Cuadrado, Antonio; Manda, Gina; Hassan, Ahmed; Alcaraz, María José; Barbas, Coral; Daiber, Andreas; Ghezzi, Pietro; León, Rafael; López, Manuela G; Oliva, Baldo; Pajares, Marta; Rojo, Ana I; Robledinos-Antón, Natalia; Valverde, Angela M; Guney, Emre; Schmidt, Harald H H W

    2018-04-01

    Systems medicine has a mechanism-based rather than a symptom- or organ-based approach to disease and identifies therapeutic targets in a nonhypothesis-driven manner. In this work, we apply this to transcription factor nuclear factor (erythroid-derived 2)-like 2 (NRF2) by cross-validating its position in a protein-protein interaction network (the NRF2 interactome) functionally linked to cytoprotection in low-grade stress, chronic inflammation, metabolic alterations, and reactive oxygen species formation. Multiscale network analysis of these molecular profiles suggests alterations of NRF2 expression and activity as a common mechanism in a subnetwork of diseases (the NRF2 diseasome). This network joins apparently heterogeneous phenotypes such as autoimmune, respiratory, digestive, cardiovascular, metabolic, and neurodegenerative diseases, along with cancer. Importantly, this approach matches and confirms in silico several applications for NRF2-modulating drugs validated in vivo at different phases of clinical development. Pharmacologically, their profile is as diverse as electrophilic dimethyl fumarate, synthetic triterpenoids like bardoxolone methyl and sulforaphane, protein-protein or DNA-protein interaction inhibitors, and even registered drugs such as metformin and statins, which activate NRF2 and may be repurposed for indications within the NRF2 cluster of disease phenotypes. Thus, NRF2 represents one of the first targets fully embraced by classic and systems medicine approaches to facilitate both drug development and drug repurposing by focusing on a set of disease phenotypes that appear to be mechanistically linked. The resulting NRF2 drugome may therefore rapidly advance several surprising clinical options for this subset of chronic diseases. Copyright © 2018 by The Author(s).

  14. Aldosterone Activates Transcription Factor Nrf2 in Kidney Cells Both In Vitro and In Vivo

    PubMed Central

    Oteiza, Patricia I.; Link, Samuel; Hey, Valentin; Stopper, Helga; Schupp, Nicole

    2014-01-01

    Abstract Aims: An increased kidney cancer risk was found in hypertensive patients, who frequently exhibit hyperaldosteronism, known to contribute to kidney injury, with oxidative stress playing an important role. The capacity of kidney cells to up-regulate transcription factor nuclear factor-erythroid-2-related factor 2 (Nrf2), a key regulator of the cellular antioxidative defense, as a prevention of aldosterone-induced oxidative damage was investigated both in vitro and in vivo. Results: Aldosterone activated Nrf2 and increased the expression of enzymes involved in glutathione (GSH) synthesis and detoxification. This activation depended on the mineralocorticoid receptor (MR) and oxidative stress. In vitro, Nrf2 activation, GSH amounts, and target gene levels decreased after 24 h, while oxidant levels remained high. Nrf2 activation could not protect cells against oxidative DNA damage, as aldosterone-induced double-strand breaks and 7,8-dihydro-8-oxo-guanine (8-oxodG) lesions steadily rose. The Nrf2 activator sulforaphane enhanced the Nrf2 response both in vitro and in vivo, thereby preventing aldosterone-induced DNA damage. In vivo, Nrf2 activation further had beneficial effects on the aldosterone-caused blood pressure increase and loss of kidney function. Innovation: This is the first study showing the activation of Nrf2 by aldosterone. Moreover, the results identify sulforaphane as a substance that is capable of preventing aldosterone-induced damage both in vivo and in vitro. Conclusion: Aldosterone-induced Nrf2 adaptive response cannot neutralize oxidative actions of chronically increased aldosterone, which, therefore could be causally involved in the increased cancer incidence of hypertensive individuals. Enhancing the cellular antioxidative defense with sulforaphane might exhibit beneficial effects. Antioxid. Redox Signal. 21, 2126–2142. PMID:24512358

  15. Erythropoietin and Nrf2: key factors in the neuroprotection provided by apo-lactoferrin.

    PubMed

    Zakharova, E T; Sokolov, A V; Pavlichenko, N N; Kostevich, V A; Abdurasulova, I N; Chechushkov, A V; Voynova, I V; Elizarova, A Yu; Kolmakov, N N; Bass, M G; Semak, I V; Budevich, A I; Kozhin, P M; Zenkov, N K; Klimenko, V M; Kirik, O V; Korzhevskii, D E; Menshchikova, E B; Vasilyev, V B

    2018-05-10

    Among the properties of lactoferrin (LF) are bactericidal, antianemic, immunomodulatory, antitumour, antiphlogistic effects. Previously we demonstrated its capacity to stabilize in vivo HIF-1-alpha and HIF-2-alpha, which are redox-sensitive multiaimed transcription factors. Various tissues of animals receiving recombinant human LF (rhLF) responded by expressing the HIF-1-alpha target genes, hence such proteins as erythropoietin (EPO), ceruloplasmin, etc. were synthesized in noticeable amounts. Among organs in which EPO synthesis occurred were brain, heart, spleen, liver, kidneys and lungs. Other researchers showed that EPO can act as a protectant against severe brain injury and status epilepticus in rats. Therefore, we tried rhLF as a protector against the severe neurologic disorders developed in rats, such as the rotenone-induced model of Parkinson's disease and experimental autoimmune encephalomyelitis as a model of multiple sclerosis, and observed its capacity to mitigate the grave symptoms. Moreover, an intraperitoneal injection of rhLF into mice 1 h after occlusion of the medial cerebral artery significantly diminished the necrosis area measured on the third day in the ischaemic brain. During this period EPO was synthesized in various murine tissues. It was known that EPO induces nuclear translocation of Nrf2, which, like HIF-1-alpha, is a transcription factor. In view that under conditions of hypoxia both factors demonstrate a synergistic protective effect, we suggested that LF activates the Keap1/Nrf2 signaling pathway, an important link in proliferation and differentiation of normal and malignant cells. J774 macrophages were cultured for 3 days without or in the presence of ferric and ferrous ions (RPMI-1640 and DMEM/F12, respectively). Then cells were incubated with rhLF or Deferiprone. Confocal microscopy revealed nuclear translocation of Nrf2 (the key event in Keap1/Nrf2 signaling) induced by apo-rhLF (iron-free, RPMI-1640). The reference compound

  16. Nrf2 protects against oxidative stress induced by SiO2 nanoparticles.

    PubMed

    Liu, Wei; Hu, Tao; Zhou, Li; Wu, Desheng; Huang, Xinfeng; Ren, Xiaohu; Lv, Yuan; Hong, Wenxu; Huang, Guanqin; Lin, Zequn; Liu, Jianjun

    2017-10-01

    The aim of our study was to explore the role of nuclear factor erythroid 2 (NF-E2)-related factor 2 (Nrf2) on the exposure of SiO 2 nanoparticles (NPs) and its influence. To understand the mechanism of NP-induced oxidative stress, the involvement of oxidative-stress-responding transcription factors and the Nrf2/antioxidant reactive element (ARE) signaling pathway in the toxicity of SiO 2 NPs' exposure was investigated via in vivo and in vitro models. A549 cells showed a significant cytotoxic effect while A549-shNrf2 cells showed decreased cell viability after nm-SiO 2 exposure. SiO 2 NPs' exposure activated the Nrf2/ARE signaling pathway. Nrf2 -/- exposed mice showed increased reactive oxygen species, 8-hydroxyl deoxyguanosine level and decreased total antioxidant capacity. Nrf2/ARE signaling pathway activation disrupted, leading inhibition of heme oxygenase-1 and upregulation of PKR-like endoplasmic-reticulum-regulated kinase. Our findings suggested that Nrf2 could protect against oxidative stress induced by SiO 2 NPs, and the Nrf2/ARE pathway might be involved in mild-to-moderate SiO 2 NP-induced oxidative stress that was evident from dampened activity of Nrf2.

  17. Possible involvement of nuclear factor erythroid 2-related factor 2 in the gene expression of Cyp2b10 and Cyp2a5.

    PubMed

    Ashino, Takashi; Ohkubo-Morita, Haruyo; Yamamoto, Masayuki; Yoshida, Takemi; Numazawa, Satoshi

    2014-01-01

    Cytochrome P450 gene expression is altered by various chemical compounds. In this study, we used nuclear factor erythroid 2-related factor 2 (Nrf2)-deficient (Nrf2(-⧸-)) mice to investigate the involvement of Nrf2 in Cyp2b10 and Cyp2a5 gene expression. Phorone, an Nrf2 activator, strongly increased Cyp2b10 and Cyp2a5 mRNA as well as Nrf2 target genes, including NAD(P)H-quinone oxidoreductase-1 and heme oxygenase-1, in wild-type mouse livers 8 h after treatment. The phorone-induced mRNA levels in Nrf2(-⧸-) mouse livers were lower than that in wild-type mouse livers. Nrf2(-⧸-) mice showed attenuated Cyp2b10 and Cyp2a5 induction by phenobarbital, a classical Cyp2b inducer. These findings suggest that the Nrf2 pathway is involved in Cyp2b10 and Cyp2a5 gene expression.

  18. Discovery and Development of Kelch-like ECH-Associated Protein 1. Nuclear Factor Erythroid 2-Related Factor 2 (KEAP1:NRF2) Protein-Protein Interaction Inhibitors: Achievements, Challenges, and Future Directions.

    PubMed

    Jiang, Zheng-Yu; Lu, Meng-Chen; You, Qi-Dong

    2016-12-22

    The transcription factor Nrf2 is the primary regulator of the cellular defense system, and enhancing Nrf2 activity has potential usages in various diseases, especially chronic age-related and inflammatory diseases. Recently, directly targeting Keap1-Nrf2 protein-protein interaction (PPI) has been an emerging strategy to selectively and effectively activate Nrf2. This Perspective summarizes the progress in the discovery and development of Keap1-Nrf2 PPI inhibitors, including the Keap1-Nrf2 regulatory mechanisms, biochemical techniques for inhibitor identification, and approaches for identifying peptide and small-molecule inhibitors, as well as discusses privileged structures and future directions for further development of Keap1-Nrf2 PPI inhibitors.

  19. Nrf2-dependent suppression of azoxymethane/dextran sulfate sodium-induced colon carcinogenesis by the cinnamon-derived dietary factor cinnamaldehyde.

    PubMed

    Long, Min; Tao, Shasha; Rojo de la Vega, Montserrat; Jiang, Tao; Wen, Qing; Park, Sophia L; Zhang, Donna D; Wondrak, Georg T

    2015-05-01

    The progressive nature of colorectal cancer and poor prognosis associated with the metastatic phase of the disease create an urgent need for the development of more efficacious strategies targeting colorectal carcinogenesis. Cumulative evidence suggests that the redox-sensitive transcription factor Nrf2 (nuclear factor-E2-related factor 2), a master regulator of the cellular antioxidant defence, represents a promising molecular target for colorectal cancer chemoprevention. Recently, we have identified cinnamon, the ground bark of Cinnamomum aromaticum (cassia cinnamon) and Cinnamomum verum (Ceylon cinnamon), as a rich dietary source of the Nrf2 inducer cinnamaldehyde (CA) eliciting the Nrf2-regulated antioxidant response in human epithelial colon cells, conferring cytoprotection against electrophilic and genotoxic insult. Here, we have explored the molecular mechanism underlying CA-induced Nrf2 activation in colorectal epithelial cells and have examined the chemopreventive potential of CA in a murine colorectal cancer model comparing Nrf2(+/+) with Nrf2(-/-) mice. In HCT116 cells, CA caused a Keap1-C151-dependent increase in Nrf2 protein half-life via blockage of ubiquitination with upregulation of cytoprotective Nrf2 target genes and elevation of cellular glutathione. After optimizing colorectal Nrf2 activation and target gene expression by dietary CA-supplementation regimens, we demonstrated that CA suppresses AOM/DSS-induced inflammatory colon carcinogenesis with modulation of molecular markers of colorectal carcinogenesis. Dietary suppression of colorectal cancer using CA supplementation was achieved in Nrf2(+/+) but not in Nrf2(-/-) mice confirming the Nrf2 dependence of CA-induced chemopreventive effects. Taken together, our data suggest feasibility of colorectal cancer suppression by dietary CA, an FDA-approved food additive derived from the third most consumed spice in the world. ©2015 American Association for Cancer Research.

  20. Decreased histone deacetylase 2 impairs Nrf2 activation by oxidative stress

    DOE Office of Scientific and Technical Information (OSTI.GOV)

    Mercado, Nicolas; Thimmulappa, Rajesh; Thomas, Catherine M.R.

    2011-03-11

    Research highlights: {yields} Nrf2 anti-oxidant function is impaired when HDAC activity is inhibited. {yields} HDAC inhibition decreases Nrf2 protein stability. {yields} HDAC2 is involved in reduced Nrf2 stability and both correlate in COPD samples. {yields} HDAC inhibition increases Nrf2 acetylation. -- Abstract: Nuclear factor erythroid 2-related factor 2 (Nrf2) plays a crucial role in cellular defence against oxidative stress by inducing the expression of multiple anti-oxidant genes. However, where high levels of oxidative stress are observed, such as chronic obstructive pulmonary disease (COPD), Nrf2 activity is reduced, although the molecular mechanism for this defect is uncertain. Here, we show thatmore » down-regulation of histone deacetylase (HDAC) 2 causes Nrf2 instability, resulting in reduced anti-oxidant gene expression and increase sensitivity to oxidative stress. Although Nrf2 protein was clearly stabilized after hydrogen peroxide (H{sub 2}O{sub 2}) stimulation in a bronchial epithelial cell line (BEAS2B), Nrf2 stability was decreased and Nrf2 acetylation increased in the presence of an HDAC inhibitor, trichostatin A (TSA). TSA also reduced Nrf2-regulated heme-oxygenase-1 (HO-1) expression in these cells, and this was confirmed in acute cigarette-smoke exposed mice in vivo. HDAC2 knock-down by RNA interference resulted in reduced H{sub 2}O{sub 2}-induced Nrf2 protein stability and activity in BEAS2B cells, whereas HDAC1 knockdown had no effect. Furthermore, monocyte-derived macrophages obtained from healthy volunteers (non-smokers and smokers) and COPD patients showed a significant correlation between HDAC2 expression and Nrf2 expression (r = 0.92, p < 0.0001). Thus, reduced HDAC2 activity in COPD may account for increased Nrf2 acetylation, reduced Nrf2 stability and impaired anti oxidant defences.« less

  1. Morris Water Maze Training in Mice Elevates Hippocampal Levels of Transcription Factors Nuclear Factor (Erythroid-derived 2)-like 2 and Nuclear Factor Kappa B p65

    PubMed Central

    Snow, Wanda M.; Pahlavan, Payam S.; Djordjevic, Jelena; McAllister, Danielle; Platt, Eric E.; Alashmali, Shoug; Bernstein, Michael J.; Suh, Miyoung; Albensi, Benedict C.

    2015-01-01

    Research has identified several transcription factors that regulate activity-dependent plasticity and memory, with cAMP-response element binding protein (CREB) being the most well-studied. In neurons, CREB activation is influenced by the transcription factor nuclear factor kappa B (NF-κB), considered central to immunity but more recently implicated in memory. The transcription factor early growth response-2 (Egr-2), an NF-κB gene target, is also associated with learning and memory. Nuclear factor (erythroid-derived 2)-like 2 (Nrf2), an antioxidant transcription factor linked to NF-κB in pathological conditions, has not been studied in normal memory. Given that numerous transcription factors implicated in activity-dependent plasticity demonstrate connections to NF-κB, this study simultaneously evaluated protein levels of NF-κB, CREB, Egr-2, Nrf2, and actin in hippocampi from young (1 month-old) weanling CD1 mice after training in the Morris water maze, a hippocampal-dependent spatial memory task. After a 6-day acquisition period, time to locate the hidden platform decreased in the Morris water maze. Mice spent more time in the target vs. non-target quadrants of the maze, suggestive of recall of the platform location. Western blot data revealed a decrease in NF-κB p50 protein after training relative to controls, whereas NF-κB p65, Nrf2 and actin increased. Nrf2 levels were correlated with platform crosses in nearly all tested animals. These data demonstrate that training in a spatial memory task results in alterations in and associations with particular transcription factors in the hippocampus, including upregulation of NF-κB p65 and Nrf2. Training-induced increases in actin protein levels caution against its use as a loading control in immunoblot studies examining activity-dependent plasticity, learning, and memory. PMID:26635523

  2. Nuclear factor erythroid 2-related factor-2 activity controls 4-hydroxynonenal metabolism and activity in prostate cancer cells.

    PubMed

    Pettazzoni, Piergiorgio; Ciamporcero, Eric; Medana, Claudio; Pizzimenti, Stefania; Dal Bello, Federica; Minero, Valerio Giacomo; Toaldo, Cristina; Minelli, Rosalba; Uchida, Koji; Dianzani, Mario Umberto; Pili, Roberto; Barrera, Giuseppina

    2011-10-15

    4-Hydroxynonenal (HNE) is an end product of lipoperoxidation with antiproliferative and proapoptotic properties in various tumors. Here we report a greater sensitivity to HNE in PC3 and LNCaP cells compared to DU145 cells. In contrast to PC3 and LNCaP cells, HNE-treated DU145 cells showed a smaller reduction in growth and did not undergo apoptosis. In DU145 cells, HNE did not induce ROS production and DNA damage and generated a lower amount of HNE-protein adducts. DU145 cells had a greater GSH and GST A4 content and GSH/GST-mediated HNE detoxification. Nuclear factor erythroid 2-related factor-2 (Nrf2) is a regulator of the antioxidant response. Nrf2 protein content and nuclear accumulation were higher in DU145 cells compared to PC3 and LNCaP cells, whereas the expression of KEAP1, the main negative regulator of Nrf2 activity, was lower. Inhibition of Nrf2 expression with specific siRNA resulted in a reduction in GST A4 expression and GS-HNE formation, indicating that Nrf2 controls HNE metabolism. In addition, Nrf2 knockdown sensitized DU145 cells to HNE-mediated antiproliferative and proapoptotic activity. In conclusion, we demonstrated that increased Nrf2 activity resulted in a reduction in HNE sensitivity in prostate cancer cells, suggesting a potential mechanism of resistance to pro-oxidant therapy. Copyright © 2011 Elsevier Inc. All rights reserved.

  3. Possible involvement of nuclear factor erythroid 2-related factor 2 in the gene expression of Cyp2b10 and Cyp2a5☆

    PubMed Central

    Ashino, Takashi; Ohkubo-Morita, Haruyo; Yamamoto, Masayuki; Yoshida, Takemi; Numazawa, Satoshi

    2014-01-01

    Cytochrome P450 gene expression is altered by various chemical compounds. In this study, we used nuclear factor erythroid 2-related factor 2 (Nrf2)–deficient (Nrf2−⧸−) mice to investigate the involvement of Nrf2 in Cyp2b10 and Cyp2a5 gene expression. Phorone, an Nrf2 activator, strongly increased Cyp2b10 and Cyp2a5 mRNA as well as Nrf2 target genes, including NAD(P)H-quinone oxidoreductase-1 and heme oxygenase-1, in wild-type mouse livers 8 h after treatment. The phorone-induced mRNA levels in Nrf2−⧸− mouse livers were lower than that in wild-type mouse livers. Nrf2−⧸− mice showed attenuated Cyp2b10 and Cyp2a5 induction by phenobarbital, a classical Cyp2b inducer. These findings suggest that the Nrf2 pathway is involved in Cyp2b10 and Cyp2a5 gene expression. PMID:24494203

  4. An Essential Role of NRF2 in Diabetic Wound Healing

    PubMed Central

    Long, Min; Rojo de la Vega, Montserrat; Wen, Qing; Bharara, Manish; Jiang, Tao; Zhang, Rui; Zhou, Shiwen; Wong, Pak K.

    2016-01-01

    The high mortality and disability of diabetic nonhealing skin ulcers create an urgent need for the development of more efficacious strategies targeting diabetic wound healing. In the current study, using human clinical specimens, we show that perilesional skin tissues from patients with diabetes are under more severe oxidative stress and display higher activation of the nuclear factor-E2–related factor 2 (NRF2)–mediated antioxidant response than perilesional skin tissues from normoglycemic patients. In a streptozotocin-induced diabetes mouse model, Nrf2−/− mice have delayed wound closure rates compared with Nrf2+/+ mice, which is, at least partially, due to greater oxidative DNA damage, low transforming growth factor-β1 (TGF-β1) and high matrix metalloproteinase 9 (MMP9) expression, and increased apoptosis. More importantly, pharmacological activation of the NRF2 pathway significantly improves diabetic wound healing. In vitro experiments in human immortalized keratinocyte cells confirm that NRF2 contributes to wound healing by alleviating oxidative stress, increasing proliferation and migration, decreasing apoptosis, and increasing the expression of TGF-β1 and lowering MMP9 under high-glucose conditions. This study indicates an essential role for NRF2 in diabetic wound healing and the therapeutic benefits of activating NRF2 in this disease, laying the foundation for future clinical trials using NRF2 activators in treating diabetic skin ulcers. PMID:26718502

  5. Nrf2 Is an Attractive Therapeutic Target for Retinal Diseases

    PubMed Central

    2016-01-01

    Nuclear factor erythroid 2-related factor 2 (Nrf2) is a redox-sensitive transcription factor that binds to antioxidant response elements located in the promoter region of genes encoding many antioxidant enzymes and phase II detoxifying enzymes. Activation of Nrf2 functions is one of the critical defensive mechanisms against oxidative stress in many species. The retina is constantly exposed to reactive oxygen species, and oxidative stress is a major contributor to age-related macular diseases. Moreover, the resulting inflammation and neuronal degeneration are also related to other retinal diseases. The well-known Nrf2 activators, bardoxolone methyl and its derivatives, have been the subject of a number of clinical trials, including those aimed at treating chronic kidney disease, pulmonary arterial hypertension, and mitochondrial myopathies. Recent studies suggest that Nrf2 activation protects the retina from retinal diseases. In particular, this is supported by the finding that Nrf2 knockout mice display age-related retinal degeneration. Moreover, the concept has been validated by the efficacy of Nrf2 activators in a number of retinal pathological models. We have also recently succeeded in generating a novel Nrf2 activator, RS9, using a biotransformation technique. This review discusses current links between retinal diseases and Nrf2 and the possibility of treating retinal diseases by activating the Nrf2 signaling pathway. PMID:27818722

  6. Translational control of Nrf2 within the open reading frame

    DOE Office of Scientific and Technical Information (OSTI.GOV)

    Perez-Leal, Oscar, E-mail: operez@temple.edu; Barrero, Carlos A.; Merali, Salim, E-mail: smerali@temple.edu

    2013-07-19

    Highlights: •Identification of a novel Nrf2 translational repression mechanism. •The repressor is within the 3′ portion of the Nrf2 ORF. •The translation of Nrf2 or eGFP is reduced by the regulatory element. •The translational repression can be reversed with synonymous codon substitutions. •The molecular mechanism requires the mRNA sequence, but not the encoded amino acids. -- Abstract: Nuclear Factor Erythroid 2-Related Factor 2 (Nrf2) is a transcription factor that is essential for the regulation of an effective antioxidant and detoxifying response. The regulation of its activity can occur at transcription, translation and post-translational levels. Evidence suggests that under environmental stressmore » conditions, new synthesis of Nrf2 is required – a process that is regulated by translational control and is not fully understood. Here we described the identification of a novel molecular process that under basal conditions strongly represses the translation of Nrf2 within the open reading frame (ORF). This mechanism is dependent on the mRNA sequence within the 3′ portion of the ORF of Nrf2 but not in the encoded amino acid sequence. The Nrf2 translational repression can be reversed with the use of synonymous codon substitutions. This discovery suggests an additional layer of control to explain the reason for the low Nrf2 concentration under quiescent state.« less

  7. Estrogen-Dependent Nrf2 Expression Protects Against Reflux-Induced Esophagitis.

    PubMed

    Torihata, Yudai; Asanuma, Kiyotaka; Iijima, Katsunori; Mikami, Tetsuhiko; Hamada, Shin; Asano, Naoki; Koike, Tomoyuki; Imatani, Akira; Masamune, Atsushi; Shimosegawa, Tooru

    2018-02-01

    Gastroesophageal reflux disease is more common in males than in females. The enhanced antioxidative capacity of estrogen in females might account for the gender difference. Nuclear factor erythroid 2-related factor 2 (Nrf2) plays a pivotal role in the host defense mechanism against oxidative stress. This study aimed to clarify the role of Nrf2 in reflux-induced esophageal inflammation, focusing on the gender difference and nitric oxide. Gastroesophageal reflux was surgically induced in male and female rats. Nitrite and ascorbic acid were administered for 1 week to provoke nitric oxide in the esophageal lumen. Male rats with gastroesophageal reflux were supplemented with 17β-estradiol or tert-butylhydroquinone, an Nrf2-inducing reagent. Esophageal squamous cell carcinoma KYSE30 cells were treated with 17β-estradiol. Nrf2 expression was examined by Western blotting and quantitative real-time PCR. Antioxidant gene expression profiles were examined by a PCR array. In the presence of nitric oxide, reflux-induced esophageal damage was less evident, whereas esophageal expression of Nrf2 and its target genes such as Nqo1 was more evident in female or male rats supplemented with 17β-estradiol than in male rats. 17β-Estradiol increased nuclear Nrf2 expression in KYSE30 cells. tert-Butylhydroquinone increased tissue Nqo1 mRNA expression, leading to a reduction in reflux-induced esophageal damage. Estrogen-dependent Nrf2 expression might contribute to protection against the development of gastroesophageal reflux disease in females.

  8. p62/Sequestosome-1, Autophagy-related Gene 8, and Autophagy in Drosophila Are Regulated by Nuclear Factor Erythroid 2-related Factor 2 (NRF2), Independent of Transcription Factor TFEB.

    PubMed

    Jain, Ashish; Rusten, Tor Erik; Katheder, Nadja; Elvenes, Julianne; Bruun, Jack-Ansgar; Sjøttem, Eva; Lamark, Trond; Johansen, Terje

    2015-06-12

    The selective autophagy receptor p62/sequestosome 1 (SQSTM1) interacts directly with LC3 and is involved in oxidative stress signaling in two ways in mammals. First, p62 is transcriptionally induced upon oxidative stress by the NF-E2-related factor 2 (NRF2) by direct binding to an antioxidant response element in the p62 promoter. Second, p62 accumulation, occurring when autophagy is impaired, leads to increased p62 binding to the NRF2 inhibitor KEAP1, resulting in reduced proteasomal turnover of NRF2. This gives chronic oxidative stress signaling through a feed forward loop. Here, we show that the Drosophila p62/SQSTM1 orthologue, Ref(2)P, interacts directly with DmAtg8a via an LC3-interacting region motif, supporting a role for Ref(2)P in selective autophagy. The ref(2)P promoter also contains a functional antioxidant response element that is directly bound by the NRF2 orthologue, CncC, which can induce ref(2)P expression along with the oxidative stress-associated gene gstD1. However, distinct from the situation in mammals, Ref(2)P does not interact directly with DmKeap1 via a KEAP1-interacting region motif; nor does ectopically expressed Ref(2)P or autophagy deficiency activate the oxidative stress response. Instead, DmAtg8a interacts directly with DmKeap1, and DmKeap1 is removed upon programmed autophagy in Drosophila gut cells. Strikingly, CncC induced increased Atg8a levels and autophagy independent of TFEB/MitF in fat body and larval gut tissues. Thus, these results extend the intimate relationship between oxidative stress-sensing NRF2/CncC transcription factors and autophagy and suggest that NRF2/CncC may regulate autophagic activity in other organisms too. © 2015 by The American Society for Biochemistry and Molecular Biology, Inc.

  9. Development of a cell-based high throughput luciferase enzyme fragment complementation assay to identify nuclear-factor-e2-related transcription factor 2 activators.

    PubMed

    Xie, Wensheng; Pao, Christina; Graham, Taylor; Dul, Ed; Lu, Quinn; Sweitzer, Thomas D; Ames, Robert S; Li, Hu

    2012-12-01

    Nuclear-factor-E2-related transcription factor 2 (Nrf2) regulates a large panel of Phase II genes and plays an important role in cell survival. Nrf2 activation has been shown as preventing cigarette smoke-induced alveolar enlargement in mice. Therefore, activation of the Nrf2 protein by small-molecule activators represents an attractive therapeutic strategy that is used for chronic obstructive pulmonary disease. In this article, we describe a cell-based luciferase enzyme fragment complementation assay that identifies Nrf2 activators. This assay is based on the interaction of Nrf2 with its nuclear partner MafK or runt-related transcription factor 2 (RunX2) and is dependent on the reconstitution of a "split" luciferase. Firefly luciferase is split into two fragments, which are genetically fused to Nrf2 and MafK or RunX2, respectively. BacMam technology was used to deliver the fusion constructs into cells for expression of the tagged proteins. When the BacMam-transduced cells were treated with Nrf2 activators, the Nrf2 protein was stabilized and translocated into the nucleus where it interacted with MafK or RunX2. The interaction of Nrf2 and MafK or RunX2 brought together the two luciferase fragments that form an active luciferase. The assay was developed in a 384-well format and was optimized by titrating the BacMam concentration, transduction time, cell density, and fetal bovine serum concentration. It was further validated with known Nrf2 activators. Our data show that this assay is robust, sensitive, and amenable to high throughput screening of a large compound collection for the identification of novel Nrf2 activators.

  10. Nuclear factor erythroid 2-related factor 2 deletion impairs glucose tolerance and exacerbates hyperglycemia in type 1 diabetic mice.

    PubMed

    Aleksunes, Lauren M; Reisman, Scott A; Yeager, Ronnie L; Goedken, Michael J; Klaassen, Curtis D

    2010-04-01

    The transcription factor nuclear factor erythroid 2-related factor 2 (Nrf2) induces a battery of cytoprotective genes after oxidative stress. Nrf2 aids in liver regeneration by altering insulin signaling; however, whether Nrf2 participates in hepatic glucose homeostasis is unknown. Compared with wild-type mice, mice lacking Nrf2 (Nrf2-null) have lower basal serum insulin and prolonged hyperglycemia in response to an intraperitoneal glucose challenge. In the present study, blood glucose, serum insulin, urine flow rate, and hepatic expression of glucose-related genes were quantified in male diabetic wild-type and Nrf2-null mice. Type 1 diabetes was induced with a single intraperitoneal dose (200 mg/kg) of streptozotocin (STZ). Histopathology and serum insulin levels confirmed depleted pancreatic beta-cells in STZ-treated mice of both genotypes. Five days after STZ, Nrf2-null mice had higher blood glucose levels than wild-type mice. Nine days after STZ, polyuria occurred in both genotypes with more urine output from Nrf2-null mice (11-fold) than wild-type mice (7-fold). Moreover, STZ-treated Nrf2-null mice had higher levels of serum beta-hydroxybutyrate, triglycerides, and fatty acids 10 days after STZ compared with wild-type mice. STZ reduced hepatic glycogen in both genotypes, with less observed in Nrf2-null mice. Increased urine output and blood glucose in STZ-treated Nrf2-null mice corresponded with enhanced gluconeogenesis (glucose-6-phosphatase and phosphoenolpyruvate carboxykinase)- and reduced glycolysis (pyruvate kinase)-related mRNA expression in their livers. Furthermore, the Nrf2 activator oltipraz lowered blood glucose in wild-type but not Nrf2-null mice administered STZ. Collectively, these data indicate that the absence of Nrf2 worsens hyperglycemia in type I diabetic mice and Nrf2 may represent a therapeutic target for reducing circulating glucose levels.

  11. Bardoxolone brings Nrf2-based therapies to light.

    PubMed

    Zhang, Donna D

    2013-08-10

    The targeted activation of nuclear factor erythroid-derived-2-like 2 (Nrf2) to alleviate symptoms of chronic kidney disease has recently garnered much attention. Unfortunately, the greatest clinical success to date, bardoxolone, failed in phase III clinical trial for unspecified safety reasons. The present letter to the editor discusses the clinical development of bardoxolone and explores potential reasons for the ultimate withdrawal from clinical trials. In particular, was the correct clinical indication pursued and would improved specificity have mitigated the safety concerns? Ultimately, it is concluded that the right clinical indication and heightened specificity will lead to successful Nrf2-based therapies. Therefore, the bardoxolone clinical results do not dampen enthusiasm for Nrf2-based therapies; rather it illuminates the clinical potential of the Nrf2 pathway as a drug target.

  12. Nrf2 activation prevents cadmium-induced acute liver injury

    DOE Office of Scientific and Technical Information (OSTI.GOV)

    Wu, Kai C.; Liu, Jie J.; Klaassen, Curtis D., E-mail: cklaasse@kumc.edu

    2012-08-15

    Oxidative stress plays an important role in cadmium-induced liver injury. Nuclear factor erythroid 2-related factor 2 (Nrf2) is a transcription factor that up-regulates cytoprotective genes in response to oxidative stress. To investigate the role of Nrf2 in cadmium-induced hepatotoxicity, Nrf2-null mice, wild-type mice, kelch-like ECH-associated protein 1-knockdown (Keap1-KD) mice with enhanced Nrf2, and Keap1-hepatocyte knockout (Keap1-HKO) mice with maximum Nrf2 activation were treated with cadmium chloride (3.5 mg Cd/kg, i.p.). Blood and liver samples were collected 8 h thereafter. Cadmium increased serum alanine aminotransferase (ALT) and lactate dehydrogenase (LDH) activities, and caused extensive hepatic hemorrhage and necrosis in the Nrf2-nullmore » mice. In contrast, Nrf2-enhanced mice had lower serum ALT and LDH activities and less morphological alternations in the livers than wild-type mice. H{sub 2}DCFDA (2′,7′-dichlorodihydrofluoresein diacetate) staining of primary hepatocytes isolated from the four genotypes of mice indicated that oxidative stress was higher in Nrf2-null cells, and lower in Nrf2-enhanced cells than in wild-type cells. To further investigate the mechanism of the protective effect of Nrf2, mRNA of metallothionein (MT) and other cytoprotective genes were determined. Cadmium markedly induced MT-1 and MT-2 in livers of all four genotypes of mice. In contrast, genes involved in glutathione synthesis and reducing reactive oxygen species, including glutamate-cysteine ligase (Gclc), glutathione peroxidase-2 (Gpx2), and sulfiredoxin-1 (Srxn-1) were only induced in Nrf2-enhanced mice, but not in Nrf2-null mice. In conclusion, the present study shows that Nrf2 activation prevents cadmium-induced oxidative stress and liver injury through induction of genes involved in antioxidant defense rather than genes that scavenge Cd. -- Highlights: ► Cadmium caused extensive hepatic hemorrhage and necrosis in Nrf2-null mice. ► Keap1-KD and Keap1

  13. Antioxidants for Healthy Skin: The Emerging Role of Aryl Hydrocarbon Receptors and Nuclear Factor-Erythroid 2-Related Factor-2

    PubMed Central

    Furue, Masutaka; Uchi, Hiroshi; Mitoma, Chikage; Hashimoto-Hachiya, Akiko; Chiba, Takahito; Ito, Takamichi; Nakahara, Takeshi; Tsuji, Gaku

    2017-01-01

    Skin is the outermost part of the body and is, thus, inevitably exposed to UV rays and environmental pollutants. Oxidative stress by these hazardous factors accelerates skin aging and induces skin inflammation and carcinogenesis. Aryl hydrocarbon receptors (AHRs) are chemical sensors that are abundantly expressed in epidermal keratinocytes and mediate the production of reactive oxygen species. To neutralize or minimize oxidative stress, the keratinocytes also express nuclear factor-erythroid 2-related factor-2 (NRF2), which is a master switch for antioxidant signaling. Notably, there is fine-tuned crosstalk between AHR and NRF2, which mutually increase or decrease their activation states. Many NRF2-mediated antioxidant phytochemicals are capable of up- and downmodulating AHR signaling. The precise mechanisms by which these phytochemicals differentially affect the AHR and NRF2 system remain largely unknown and warrant future investigation. PMID:28273792

  14. Antioxidants for Healthy Skin: The Emerging Role of Aryl Hydrocarbon Receptors and Nuclear Factor-Erythroid 2-Related Factor-2.

    PubMed

    Furue, Masutaka; Uchi, Hiroshi; Mitoma, Chikage; Hashimoto-Hachiya, Akiko; Chiba, Takahito; Ito, Takamichi; Nakahara, Takeshi; Tsuji, Gaku

    2017-03-03

    Skin is the outermost part of the body and is, thus, inevitably exposed to UV rays and environmental pollutants. Oxidative stress by these hazardous factors accelerates skin aging and induces skin inflammation and carcinogenesis. Aryl hydrocarbon receptors (AHRs) are chemical sensors that are abundantly expressed in epidermal keratinocytes and mediate the production of reactive oxygen species. To neutralize or minimize oxidative stress, the keratinocytes also express nuclear factor-erythroid 2-related factor-2 (NRF2), which is a master switch for antioxidant signaling. Notably, there is fine-tuned crosstalk between AHR and NRF2, which mutually increase or decrease their activation states. Many NRF2-mediated antioxidant phytochemicals are capable of up- and downmodulating AHR signaling. The precise mechanisms by which these phytochemicals differentially affect the AHR and NRF2 system remain largely unknown and warrant future investigation.

  15. Piper betle induces phase I & II genes through Nrf2/ARE signaling pathway in mouse embryonic fibroblasts derived from wild type and Nrf2 knockout cells.

    PubMed

    Wan Hasan, Wan Nuraini; Kwak, Mi-Kyoung; Makpol, Suzana; Wan Ngah, Wan Zurinah; Mohd Yusof, Yasmin Anum

    2014-02-23

    Nuclear factor-erythroid 2 p45 related factor 2 (Nrf2) is a primary transcription factor, protecting cells from oxidative stress by regulating a number of antioxidants and phase II detoxifying enzymes. Dietary components such as sulforaphane in broccoli and quercetin in onions have been shown to be inducers of Nrf2. Piper betle (PB) grows well in tropical climate and the leaves are used in a number of traditional remedies for the treatment of stomach ailments and infections among Asians. The aim of this study was to elucidate the effect of Piper betle (PB) leaves extract in Nrf2 signaling pathway by using 2 types of cells; mouse embryonic fibroblasts (MEFs) derived from wild-type (WT) and Nrf2 knockout (N0) mice. WT and N0 cells were treated with 5 and 10 μg/ml of PB for 10 and 12-h for the determination of nuclear translocation of Nrf2 protein. Luciferase reporter gene activity was performed to evaluate the antioxidant response element (ARE)-induction by PB. Real-time PCR and Western blot were conducted on both WT and N0 cells after PB treatment for the determination of antioxidant enzymes [superoxide dismutase (SOD1) and heme-oxygenase (HO-1)], phase I oxidoreductase enzymes [ quinone oxidoreductase (NQO1)] and phase II detoxifying enzyme [glutathione S-transferase (GST)]. Nuclear translocation of Nrf2 by PB in WT cells was better after 10 h incubation compared to 12 h. Real time PCR and Western blot analysis showed increased expressions of Nrf2, NQO1 and GSTA1 genes with corresponding increases in glutathione, NQO1 and HO-1 proteins in WT cells. Reporter gene ARE was stimulated by PB as shown by ARE/luciferase assay. Interestingly, PB induced SOD1 gene and protein expressions in N0 cells but not in WT cells. The results of this study confirmed that PB activated Nrf2-ARE signaling pathway which subsequently induced some phase I oxidoreductase, phase II detoxifying and antioxidant genes expression via ARE reporter gene involved in the Nrf2 pathway with the

  16. Piper betle induces phase I & II genes through Nrf2/ARE signaling pathway in mouse embryonic fibroblasts derived from wild type and Nrf2 knockout cells

    PubMed Central

    2014-01-01

    Background Nuclear factor-erythroid 2 p45 related factor 2 (Nrf2) is a primary transcription factor, protecting cells from oxidative stress by regulating a number of antioxidants and phase II detoxifying enzymes. Dietary components such as sulforaphane in broccoli and quercetin in onions have been shown to be inducers of Nrf2. Piper betle (PB) grows well in tropical climate and the leaves are used in a number of traditional remedies for the treatment of stomach ailments and infections among Asians. The aim of this study was to elucidate the effect of Piper betle (PB) leaves extract in Nrf2 signaling pathway by using 2 types of cells; mouse embryonic fibroblasts (MEFs) derived from wild-type (WT) and Nrf2 knockout (N0) mice. Methods WT and N0 cells were treated with 5 and 10 μg/ml of PB for 10 and 12-h for the determination of nuclear translocation of Nrf2 protein. Luciferase reporter gene activity was performed to evaluate the antioxidant response element (ARE)-induction by PB. Real-time PCR and Western blot were conducted on both WT and N0 cells after PB treatment for the determination of antioxidant enzymes [superoxide dismutase (SOD1) and heme-oxygenase (HO-1)], phase I oxidoreductase enzymes [NAD(P)H: quinone oxidoreductase (NQO1)] and phase II detoxifying enzyme [glutathione S-transferase (GST)]. Results Nuclear translocation of Nrf2 by PB in WT cells was better after 10 h incubation compared to 12 h. Real time PCR and Western blot analysis showed increased expressions of Nrf2, NQO1 and GSTA1 genes with corresponding increases in glutathione, NQO1 and HO-1 proteins in WT cells. Reporter gene ARE was stimulated by PB as shown by ARE/luciferase assay. Interestingly, PB induced SOD1 gene and protein expressions in N0 cells but not in WT cells. Conclusion The results of this study confirmed that PB activated Nrf2-ARE signaling pathway which subsequently induced some phase I oxidoreductase, phase II detoxifying and antioxidant genes expression via ARE reporter

  17. Activation of Nrf2 by H2O2: de novo synthesis versus nuclear translocation.

    PubMed

    Covas, Gonçalo; Marinho, H Susana; Cyrne, Luísa; Antunes, Fernando

    2013-01-01

    The most common mechanism described for the activation of the transcription factor Nrf2 is based on the inhibition of its degradation in the cytosol followed by its translocation to the nucleus. Recently, Nrf2 de novo synthesis was proposed as an additional mechanism for the rapid upregulation of Nrf2 by hydrogen peroxide (H2O2). Here, we describe a detailed protocol, including solutions, pilot experiments, and experimental setups, which allows exploring the role of H2O2, delivered either as a bolus or as a steady state, in endogenous Nrf2 translocation and synthesis. We also show experimental data, illustrating that H2O2 effects on Nrf2 activation in HeLa cells are strongly dependent both on the H2O2 concentration and on the method of H2O2 delivery. The de novo synthesis of Nrf2 is triggered within 5min of exposure to low concentrations of H2O2, preceding Nrf2 translocation to the nucleus which is slower. Evidence of de novo synthesis of Nrf2 is observed only for low H2O2 steady-state concentrations, a condition that is prevalent in vivo. This study illustrates the applicability of the steady-state delivery of H2O2 to uncover subtle regulatory effects elicited by H2O2 in narrow concentration and time ranges. Copyright © 2013 Elsevier Inc. All rights reserved.

  18. Nuclear factor-E2-related factor 2 is a major determinant of bile acid homeostasis in the liver and intestine

    PubMed Central

    Weerachayaphorn, Jittima; Mennone, Albert; Soroka, Carol J.; Harry, Kathy; Hagey, Lee R.; Kensler, Thomas W.

    2012-01-01

    The transcription factor nuclear factor-E2-related factor 2 (Nrf2) is a key regulator for induction of hepatic detoxification and antioxidant mechanisms, as well as for certain hepatobiliary transporters. To examine the role of Nrf2 in bile acid homeostasis and cholestasis, we assessed the determinants of bile secretion and bile acid synthesis and transport before and after bile duct ligation (BDL) in Nrf2−/− mice. Our findings indicate reduced rates of biliary bile acid and GSH excretion, higher levels of intrahepatic bile acids, and decreased expression of regulators of bile acid synthesis, Cyp7a1 and Cyp8b1, in Nrf2−/− compared with wild-type control mice. The mRNA expression of the bile acid transporters bile salt export pump (Bsep) and organic solute transporter (Ostα) were increased in the face of impaired expression of the multidrug resistance-associated proteins Mrp3 and Mrp4. Deletion of Nrf2 also decreased ileal apical sodium-dependent bile acid transporter (Asbt) expression, leading to reduced bile acid reabsorption and increased loss of bile acid in feces. Finally, when cholestasis is induced by BDL, liver injury was not different from that in wild-type BDL mice. These Nrf2−/− mice also had increased pregnane X receptor (Pxr) and Cyp3a11 mRNA expression in association with enhanced hepatic bile acid hydroxylation. In conclusion, this study finds that Nrf2 plays a major role in the regulation of bile acid homeostasis in the liver and intestine. Deletion of Nrf2 results in a cholestatic phenotype but does not augment liver injury following BDL. PMID:22345550

  19. Deficiency in the nuclear factor E2-related factor 2 renders pancreatic β-cells vulnerable to arsenic-induced cell damage

    PubMed Central

    Yang, Bei; Fu, Jingqi; Zheng, Hongzhi; Xue, Peng; Yarborough, Kathy; Woods, Courtney G; Hou, Yongyong; Zhang, Qiang; Andersen, Melvin E.; Pi, Jingbo

    2012-01-01

    Chronic human exposure to inorganic arsenic (iAs), a potent environmental oxidative stressor, is associated with increased prevalence of Type 2 diabetes, where impairment of pancreatic β-cell function is a key pathogenic factor. Nuclear factor E2-related factor 2 (Nrf2) is a central transcription factor regulating cellular adaptive response to oxidative stress. However, persistent activation of Nrf2 in response to chronic oxidative stress, including inorganic arsenite (iAs3+) exposure, blunts glucose-triggered reactive oxygen species (ROS) signaling and impairs glucose-stimulated insulin secretion (GSIS). In the current study, we found that MIN6 pancreatic β-cells with stable knockdown of Nrf2 (Nrf2-KD) by lentiviral shRNA and pancreatic islets isolated from Nrf2-knockout (Nrf2−/−) mice exhibited reduced expression of several antioxidant and detoxification enzymes in response to acute iAs3+ exposure. As a result, Nrf2-KD MIN6 cells and Nrf2−/− islets were more susceptible to iAs3+ and monomethylarsonous acid (MMA3+)-induced cell damage, as measured by decreased cell viability, augmented apoptosis and morphological change. Pretreatment of MIN6 cells with Nrf2 activator tert-butylhydroquinone protected the cells from iAs3+-induced cell damage in an Nrf2-dependent fashion. In contrast, antioxidant N-acetyl cysteine protected Nrf2-KD MIN6 cells against acute cytotoxicity of iAs3+. The present study demonstrates that Nrf2-mediated antioxidant response is critical in the pancreatic β-cell defense mechanism against acute cytotoxicity by arsenic. The findings here, combined with our previous results on the inhibitory effect of antioxidants on ROS signaling and GSIS, suggest that Nrf2 plays paradoxical roles in pancreatic β-cell dysfunction induced by environmental arsenic exposure. PMID:23000044

  20. Comparison of hepatic NRF2 and AHR binding in 2,3,7,8-tetrachlorodibenzo-p-dioxin (TCDD) treated mice demonstrates NRF2-independent PKM2 induction.

    PubMed

    Nault, Rance; Doskey, Claire M; Fader, Kelly A; Rockwell, Cheryl E; Zacharewski, Timothy R

    2018-05-11

    2,3,7,8-Tetrachlorodibenzo- p -dioxin (TCDD) induces hepatic oxidative stress following activation of the aryl hydrocarbon receptor (AhR). Our recent studies showed TCDD induced pyruvate kinase muscle isoform 2 ( Pkm2 ) as a novel antioxidant response in normal differentiated hepatocytes. To investigate cooperative regulation between nuclear factor, erythroid derived 2, like 2 ( Nrf2 ) and the AhR in the induction of Pkm2 , hepatic ChIP-seq analyses were integrated with RNA-seq time course data from mice treated with TCDD for 2 - 168h. ChIP-seq analysis 2h after TCDD treatment identified genome-wide NRF2 enrichment. Approximately 842 NRF2 enriched regions were located in the regulatory region of differentially expressed genes (DEGs) while 579 DEGs showed both NRF2 and AhR enrichment. Sequence analysis of regions with overlapping NRF2 and AhR enrichment showed over-representation of either antioxidant or dioxin response elements (ARE and DRE, respectively), although 18 possessed both motifs. NRF2 exhibited negligible enrichment within a closed Pkm chromatin region while the AhR was enriched 29-fold. Furthermore, TCDD induced Pkm2 in primary hepatocytes from wild-type and Nrf2 null mice, indicating NRF2 is not required. Although NRF2 and AhR cooperate to regulate numerous antioxidant gene expression responses, the induction of Pkm2 by TCDD is independent of ROS-mediated NRF2 activation. The American Society for Pharmacology and Experimental Therapeutics.

  1. Enhancement of the Effect of Methyl Pyropheophorbide-a-Mediated Photodynamic Therapy was Achieved by Increasing ROS through Inhibition of Nrf2-HO-1 or Nrf2-ABCG2 Signaling.

    PubMed

    Tian, Si; Yong, Min; Zhu, Jiang; Zhang, Li; Pan, Li; Chen, Qing; Li, Kai-Ting; Kong, Yu-Han; Jiang, Yuan; Yu, Ting-He; Yu, Le-Hua; Bai, Ding-Qun

    2017-01-01

    Emerging evidence indicates that the transcription factor nuclear factor-E2-related factor 2 (Nrf2) plays an essential role in cellular defense against oxidative stress; its activation has been related to cytoprotection. Here, we investigated the role of Nrf2 in improving the efficacy of methyl pyropheophorbide-amediated photodynamic therapy (Mppa-PDT) via the downregulation of Nrf2. Human ovarian cancer A2780 cells and SKOV3 cells were treated with Mppa-PDT and siRNA transfection was performed to inhibit Nrf2. After treated with siRNA and Mppa-PDT, the cell viability was examined with CCK-8 assay; cell apoptosis was detected tested by flow cytometry with Annexin V-FITC/PI; the celluar reactive oxygen species (ROS) and mitochondrial membrane potential were measured with DCFHDA and JC-1 staining; expression of protein was assessed by western blot analysis. We found that Nrf2 translocated from the cytoplasm to the nucleus in vitro and in vivo, and the expression of Nrf2 and P-Nrf2 increased through a possible mechanism regulated by mitogen-activated protein kinase (MAPK) after Mppa-PDT treatment. Furthermore, cytotoxicity and apoptosis induced by Mppa-PDT increased after Nrf2down-regulation. Nrf2 down -regulation increased reactive oxygen species (ROS) levels by attenuating antioxidants or pumping Mppa out of cells,which resulted from the inhibition of Nrf2-HO-1 or Nrf2- ABCG2 signaling. In addition, SKOV3 cells exhibited increased resistance to Mppa-PDT, and the expression levels of P-Nrf2 and ABCG2 were higher in SKOV3 cells than in A2780 cells, suggesting that Nrf2-ABCG2 signaling might be involved in the intrinsic resistanceto Mppa-PDT. These results provided evidence that Nrf2 down-regulation can enhance the effect of Mppa-PDT. Copyright© Bentham Science Publishers; For any queries, please email at epub@benthamscience.org.

  2. Cynaropicrin attenuates UVB-induced oxidative stress via the AhR-Nrf2-Nqo1 pathway.

    PubMed

    Takei, Kenjiro; Hashimoto-Hachiya, Akiko; Takahara, Masakazu; Tsuji, Gaku; Nakahara, Takeshi; Furue, Masutaka

    2015-04-16

    Due to its antioxidant and anti-inflammatory activities, artichoke (Cynara scolymus) has been used as folk medicine to treat various diseases. Cynaropicrin (Cyn), a sesquiterpene lactone, is the major bioactive phytochemical in the artichoke; however, its pharmacological mechanism remains unknown. Because some phytochemicals exert their antioxidant activity by activating aryl hydrocarbon receptor (AhR), leading to subsequent induction of the antioxidant pathway including nuclear factor E2-related factor 2 (Nrf2) and quinone oxidoreductase 1 (Nqo1), we investigated whether Cyn also activates the AhR-Nrf2-Nqo1 pathway. Cyn indeed induced the activation (nuclear translocation) of AhR, leading to nuclear translocation of Nrf2 and dose-dependent upregulation of Nrf2 and Nqo1 mRNAs in human keratinocytes. The Cyn-induced AhR-Nrf2-Nqo1 activation was AhR- and Nrf2-dependent, as demonstrated by the observation that it was absent in keratinocytes transfected by siRNA against either AhR or Nrf2. In accordance with these findings, Cyn actively inhibited generation of reactive oxygen species from keratinocytes irradiated with ultraviolet B (UVB) in a Nrf2-dependent manner. Cyn also inhibited the production of proinflammatory cytokines such as interleukin 6 and tumor necrosis factor-α from UVB-treated keratinocytes. Our findings demonstrate that Cyn is a potent activator of the AhR-Nrf2-Nqo1 pathway, and could therefore be applied to prevention of UVB-induced photo aging. Copyright © 2015 Elsevier Ireland Ltd. All rights reserved.

  3. Natural product-derived pharmacological modulators of Nrf2/ARE pathway for chronic diseases.

    PubMed

    Kumar, Hemant; Kim, In-Su; More, Sandeep Vasant; Kim, Byung-Wook; Choi, Dong-Kug

    2014-01-01

    Covering: 2000 to 2013. Oxidative stress is the central component of chronic diseases. The nuclear factor erythroid 2-related factor 2/antioxidant response element (Nrf2/ARE) pathway is vital in the up-regulation of cytoprotective genes and enzymes in response to oxidative stress and treatment with certain dietary phytochemicals. Herein, we classify bioactive compounds derived from natural products that are Nrf2/ARE pathway activators and recapitulate the molecular mechanisms for inducing Nrf2 to provide favorable effects in experimental models of chronic diseases. Moreover, pharmacological inhibition of Nrf2 signalling has emerged as promising strategy against multi-drug resistance thereby improving the treatment efficacy. We have also enlisted natural product-derived inhibitors of Nrf2/ARE pathway.

  4. Bardoxolone Brings Nrf2-Based Therapies to Light

    PubMed Central

    2013-01-01

    Abstract The targeted activation of nuclear factor erythroid-derived-2-like 2 (Nrf2) to alleviate symptoms of chronic kidney disease has recently garnered much attention. Unfortunately, the greatest clinical success to date, bardoxolone, failed in phase III clinical trial for unspecified safety reasons. The present letter to the editor discusses the clinical development of bardoxolone and explores potential reasons for the ultimate withdrawal from clinical trials. In particular, was the correct clinical indication pursued and would improved specificity have mitigated the safety concerns? Ultimately, it is concluded that the right clinical indication and heightened specificity will lead to successful Nrf2-based therapies. Therefore, the bardoxolone clinical results do not dampen enthusiasm for Nrf2-based therapies; rather it illuminates the clinical potential of the Nrf2 pathway as a drug target. Antioxid. Redox Signal. 19, 517–518. PMID:23227819

  5. Activation of the nuclear factor E2-related factor 2/anitioxidant response element alleviates the nitroglycerin-induced hyperalgesia in rats.

    PubMed

    Di, Wei; Shi, Xiaolei; Lv, Hua; Liu, Jun; Zhang, Hong; Li, Zhiwei; Fang, Yannan

    2016-12-01

    Antioxidants have been proven to weaken hyperalgesia in neuropathic pain. Endogenous antioxidant defense system may have a role in the prevention of hyperalgesia in migraine. In this study, we aimed to evaluate the role of nuclear factor E2-related factor 2/antioxidant response element (Nrf2/ARE) pathway in regulating the activation of the trigeminovascular system (TGVS) and hypersensitivity in nitroglycerin (NTG)-induced hyperalgesia rats. The expression levels of Nrf2, HO, HO1, and NQO1 in the trigeminal nucleus caudalis (TNC) were detected by western blot. Immunofluorescence was used to demonstrate the cell-specific localization of Nrf2 in TNC. Sulforaphane, a Nrf2 activator, was administered to NTG-induced rats. Then, the number of c-Fos- and nNOS-immunoreactive neurons in TNC was evaluated using immunofluorescence, and c-Fos and nNOS protein levels were quantified using western blot. Von Frey hair testing was used to evaluate the tactile thresholds of rats at different time points in different groups. Total cellular and nuclear levels of the proteins Nrf2, HO1, and NQO1 were elevated in TNC after NTG injection, and Nrf2 was found to be located in the nucleus and cytoplasm of the neurons. Sulforaphane pretreatment significantly increased the nuclear Nrf2, HO1, and NQO1 levels in TNC. In addition, sulforaphane exposure effectively inhibited the expression of nNOS and c-Fos, reduced the number of nNOS and c-Fos immunoreactive neurons in TNC, and attenuated the tactile thresholds induced by NTG injection. Oxidative stress was involved in nitroglycerin-induced hyperalgesia. Activation of the Nrf2/ARE pathway inhibited the activation of TGVS and prevented the induction of hyperalgesia. Sulforaphane might therefore be an effective agent for hyperalgesia. Further studies are needed to discover the underlying mechanisms of the process.

  6. The role of Nrf2 in oxidative stress-induced endothelial injuries.

    PubMed

    Chen, Bo; Lu, Yanrong; Chen, Younan; Cheng, Jingqiu

    2015-06-01

    Endothelial dysfunction is an important risk factor for cardiovascular disease, and it represents the initial step in the pathogenesis of atherosclerosis. Failure to protect against oxidative stress-induced cellular damage accounts for endothelial dysfunction in the majority of pathophysiological conditions. Numerous antioxidant pathways are involved in cellular redox homeostasis, among which the nuclear factor-E2-related factor 2 (Nrf2)/Kelch-like ECH-associated protein 1 (Keap1)-antioxidant response element (ARE) signaling pathway is perhaps the most prominent. Nrf2, a transcription factor with a high sensitivity to oxidative stress, binds to AREs in the nucleus and promotes the transcription of a wide variety of antioxidant genes. Nrf2 is located in the cytoskeleton, adjacent to Keap1. Keap1 acts as an adapter for cullin 3/ring-box 1-mediated ubiquitination and degradation of Nrf2, which decreases the activity of Nrf2 under physiological conditions. Oxidative stress causes Nrf2 to dissociate from Keap1 and to subsequently translocate into the nucleus, which results in its binding to ARE and the transcription of downstream target genes. Experimental evidence has established that Nrf2-driven free radical detoxification pathways are important endogenous homeostatic mechanisms that are associated with vasoprotection in the setting of aging, atherosclerosis, hypertension, ischemia, and cardiovascular diseases. The aim of the present review is to briefly summarize the mechanisms that regulate the Nrf2/Keap1-ARE signaling pathway and the latest advances in understanding how Nrf2 protects against oxidative stress-induced endothelial injuries. Further studies regarding the precise mechanisms by which Nrf2-regulated endothelial protection occurs are necessary for determining whether Nrf2 can serve as a therapeutic target in the treatment of cardiovascular diseases. © 2015 Society for Endocrinology.

  7. An Essential Role of NRF2 in Diabetic Wound Healing.

    PubMed

    Long, Min; Rojo de la Vega, Montserrat; Wen, Qing; Bharara, Manish; Jiang, Tao; Zhang, Rui; Zhou, Shiwen; Wong, Pak K; Wondrak, Georg T; Zheng, Hongting; Zhang, Donna D

    2016-03-01

    The high mortality and disability of diabetic nonhealing skin ulcers create an urgent need for the development of more efficacious strategies targeting diabetic wound healing. In the current study, using human clinical specimens, we show that perilesional skin tissues from patients with diabetes are under more severe oxidative stress and display higher activation of the nuclear factor-E2-related factor 2 (NRF2)-mediated antioxidant response than perilesional skin tissues from normoglycemic patients. In a streptozotocin-induced diabetes mouse model, Nrf2(-/-) mice have delayed wound closure rates compared with Nrf2(+/+) mice, which is, at least partially, due to greater oxidative DNA damage, low transforming growth factor-β1 (TGF-β1) and high matrix metalloproteinase 9 (MMP9) expression, and increased apoptosis. More importantly, pharmacological activation of the NRF2 pathway significantly improves diabetic wound healing. In vitro experiments in human immortalized keratinocyte cells confirm that NRF2 contributes to wound healing by alleviating oxidative stress, increasing proliferation and migration, decreasing apoptosis, and increasing the expression of TGF-β1 and lowering MMP9 under high-glucose conditions. This study indicates an essential role for NRF2 in diabetic wound healing and the therapeutic benefits of activating NRF2 in this disease, laying the foundation for future clinical trials using NRF2 activators in treating diabetic skin ulcers. © 2016 by the American Diabetes Association. Readers may use this article as long as the work is properly cited, the use is educational and not for profit, and the work is not altered.

  8. Hemistepsin A ameliorates acute inflammation in macrophages via inhibition of nuclear factor-κB and activation of nuclear factor erythroid 2-related factor 2.

    PubMed

    Kim, Jae Kwang; Lee, Ji Eun; Jung, Eun Hye; Jung, Ji Yun; Jung, Dae Hwa; Ku, Sae Kwang; Cho, Il Je; Kim, Sang Chan

    2018-01-01

    Hemistepsin A (HsA) is a sesquiterpene lactone isolated from Hemistepta lyrata (Bunge) Bunge. We investigated the anti-inflammatory effects of HsA and sought to determine its mechanisms of action in macrophages. HsA pretreatment inhibited nitric oxide production, and reduced the expression of iNOS and COX-2 in Toll-like receptor ligand-stimulated RAW 264.7 cells. Additionally, HsA decreased the secretion of proinflammatory cytokines in lipopolysaccharide (LPS)-stimulated Kupffer cells as well as in RAW 264.7 cells. HsA inhibited phosphorylation of IKKα/β and degradation of IκBα, resulting in decreased nuclear translocation of nuclear factor-κB (NF-κB) and its transcriptional activity. Moreover, HsA phosphorylated nuclear factor erythroid 2-related factor 2 (Nrf2), increased expression levels of antioxidant genes, and attenuated LPS-stimulated H 2 O 2 production. Phosphorylation of p38 and c-Jun N-terminal kinase was required for HsA-mediated Nrf2 phosphorylation. In a D-galactosamine/LPS-induced liver injury model, HsA ameliorated D-galactosamine/LPS-induced hepatocyte degeneration and inflammatory cells infiltration. Moreover, immunohistochemical analyses using nitrotyrosine, 4-hydroxynonenal, and cleaved poly (ADP-ribose) polymerase antibodies revealed that HsA protected the liver from oxidative stress. Furthermore, HsA reduced the numbers of proinflammatory cytokine-positive cells in hepatic tissues. Thus, these results suggest HsA may be a promising natural product to manage inflammation-mediated tissue injuries through inhibition of NF-κB and activation of Nrf2. Copyright © 2017 Elsevier Ltd. All rights reserved.

  9. Introducing the "TCDD-inducible AhR-Nrf2 gene battery".

    PubMed

    Yeager, Ronnie L; Reisman, Scott A; Aleksunes, Lauren M; Klaassen, Curtis D

    2009-10-01

    2,3,7,8-Tetrachlorodibenzo-p-dioxin (TCDD) induces genes via the transcription factor aryl hydrocarbon receptor (AhR), including Cyp1a1, NAD(P)H:quinone oxidoreductase 1 (Nqo1), UDP-glucuronosyltransferase 1a6 (Ugt1a6), and glutathione S-transferase a1 (Gsta1). These genes are referred to as the "AhR gene battery." However, Nqo1 is also considered a prototypical target gene of the transcription factor nuclear factor erythroid 2-related factor 2 (Nrf2). In mice, TCDD induction of Nrf2 and Nrf2 target, Nqo1, is dependent on AhR, and thus TCDD induction of drug-processing genes may be routed through an AhR-Nrf2 sequence. There has been speculation that Nrf2 may be involved in the TCDD induction of drug-processing genes; however, the data are not definitive. Therefore, to address whether TCDD induction of Nqo1, Ugts, and Gsts is dependent on Nrf2, we conducted the definitive experiment by administering TCDD (50 mug/kg, ip) to Nrf2-null and wild-type (WT) mice and collecting livers 24 h later to quantify the mRNA of drug-processing genes. TCDD induction of Cyp1a1 and Ugt1a1 was similar in WT and Nrf2-null mice, whereas TCDD induction of Ugt1a5 and 1a9 was blunted in Nrf2-null mice. TCDD induced Nqo1, Ugt1a6, 2b34, 2b35, 2b36, UDP-glucuronic acid-synthesizing gene UDP-glucose dehydrogenase, and Gsta1, m1, m2, m3, m6, p2, t2, and microsomal Gst1 in WT mice but not in Nrf2-null mice. Therefore, the present study demonstrates the novel finding that Nrf2 is required for TCDD induction of classical AhR battery genes Nqo1, Ugt1a6, and Gsta1, as well as most Ugt and Gst isoforms in livers of mice.

  10. Disruption of the Transcription Factor Nrf2 Promotes Pro-Oxidative Dendritic Cells That Stimulate Th2-Like Immunoresponsiveness upon Activation by Ambient Particulate Matter

    PubMed Central

    Williams, Marc A.; Rangasamy, Tirumalai; Bauer, Stephen M.; Killedar, Smruti; Karp, Matthew; Kensler, Thomas W.; Yamamoto, Masayuki; Breysse, Patrick; Biswal, Shyam; Georas, Steve N.

    2011-01-01

    Oxidative stress is important in dendritic cell (DC) activation. Environmental particulate matter (PM) directs pro-oxidant activities that may alter DC function. Nuclear erythroid 2 p45-related factor 2 (Nrf2) is a redox-sensitive transcription factor that regulates expression of antioxidant and detoxification genes. Oxidative stress and defective antioxidant responses may contribute to the exacerbations of asthma. We hypothesized that PM would impart differential responses by Nrf2 wild-type DCs as compared with Nrf2−/− DCs. We found that the deletion of Nrf2 affected important constitutive functions of both bone marrow-derived and highly purified myeloid lung DCs such as the secretion of inflammatory cytokines and their ability to take up exogenous Ag. Stimulation of Nrf2−/− DCs with PM augmented oxidative stress and cytokine production as compared with resting or Nrf2+/+ DCs. This was associated with the enhanced induction of Nrf2-regulated antioxidant genes. In contrast to Nrf2+/+ DCs, coincubation of Nrf2−/− DCs with PM and the antioxidant N-acetyl cysteine attenuated PM-induced up-regulation of CD80 and CD86. Our studies indicate a previously underappreciated role of Nrf2 in innate immunity and suggest that deficiency in Nrf2-dependent pathways may be involved in susceptibility to the adverse health effects of air pollution in part by promoting Th2 cytokine responses in the absence of functional Nrf2. Moreover, our studies have uncovered a hierarchal response to oxidative stress in terms of costimulatory molecule expression and cytokine secretion in DCs and suggest an important role of heightened oxidative stress in proallergic Th2-mediated immune responses orchestrated by DCs. PMID:18802057

  11. Role of NF-E2 related factor 2 (Nrf2) on chemotherapy resistance in acute myeloid leukemia (AML) and the effect of pharmacological inhibition of Nrf2.

    PubMed

    Karathedath, Sreeja; Rajamani, Bharathi M; Musheer Aalam, Syed Mohammed; Abraham, Ajay; Varatharajan, Savitha; Krishnamurthy, Partha; Mathews, Vikram; Velayudhan, Shaji Ramachandran; Balasubramanian, Poonkuzhali

    2017-01-01

    Cytarabine (Ara-C) and Daunorubicin (Dnr) forms the backbone of acute myeloid leukemia (AML) therapy. Drug resistance and toxic side effects pose a major threat to treatment success and hence alternate less toxic therapies are warranted. NF-E2 related factor-2 (Nrf2), a master regulator of antioxidant response is implicated in chemoresistance in solid tumors. However, little is known about the role of Nrf2 in AML chemoresistance and the effect of pharmacological inhibitor brusatol in modulating this resistance. Primary AML samples with high ex-vivo IC50 to Ara-C, ATO, Dnr had significantly high NRF2 RNA expression. Gene-specific knockdown of NRF2 improved sensitivity to these drugs in resistant AML cell lines by decreasing the expression of downstream antioxidant targets of Nrf2 by compromising the cell's ability to scavenge the ROS. Treatment with brusatol, a pharmacological inhibitor of Nrf2, improved sensitivity to Ara-C, ATO, and Dnr and reduced colony formation capacity. AML cell lines stably overexpressing NRF2 showed increased resistance to ATO, Dnr and Ara-C and increased expression of downstream targets. This study demonstrates that Nrf2 could be an ideal druggable target in AML, more so to the drugs that function through ROS, suggesting the possibility of using Nrf2 inhibitors in combination with chemotherapeutic agents to modulate drug resistance in AML.

  12. NRF2-regulation in brain health and disease: implication of cerebral inflammation

    PubMed Central

    Sandberg, Mats; Patil, Jaspal; D’Angelo, Barbara; Weber, Stephen G; Mallard, Carina

    2014-01-01

    The nuclear factor erythroid 2 related factor 2 (NRF2) is a key regulator of endogenous inducible defense systems in the body. Under physiological conditions NRF2 is mainly located in the cytoplasm. However, in response to oxidative stress, NRF2 translocates to the nucleus and binds to specific DNA sites termed “anti-oxidant response elements” or “electrophile response elements” to initiate transcription of cytoprotective genes. Acute oxidative stress to the brain, such as stroke and traumatic brain injury is increased in animals that are deficient in NRF2. Insufficient NRF2 activation in humans has been linked to chronic diseases such as Parkinson’s disease, Alzheimer’s disease and amyotrophic lateral sclerosis. New findings have also linked activation of the NRF2 system to anti-inflammatory effects via interactions with NF-κB. Here we review literature on cellular mechanisms of NRF2 regulation, how to maintain and restore NRF2 function and the relationship between NRF2 regulation and brain damage. We bring forward the hypothesis that inflammation via prolonged activation of key kinases (p38 and GSK-3β) and activation of histone deacetylases gives rise to dysregulation of the NRF2 system in the brain, which contributes to oxidative stress and injury. PMID:24262633

  13. Deficiency in the nuclear factor E2-related factor 2 renders pancreatic β-cells vulnerable to arsenic-induced cell damage

    DOE Office of Scientific and Technical Information (OSTI.GOV)

    Yang, Bei; Department of Histology and Embryology, College of Basic Medical Sciences, China Medical University, Shenyang 110001; Fu, Jingqi

    2012-11-01

    Chronic human exposure to inorganic arsenic (iAs), a potent environmental oxidative stressor, is associated with increased prevalence of type 2 diabetes, where impairment of pancreatic β-cell function is a key pathogenic factor. Nuclear factor E2-related factor 2 (Nrf2) is a central transcription factor regulating cellular adaptive response to oxidative stress. However, persistent activation of Nrf2 in response to chronic oxidative stress, including inorganic arsenite (iAs{sup 3+}) exposure, blunts glucose-triggered reactive oxygen species (ROS) signaling and impairs glucose-stimulated insulin secretion (GSIS). In the current study, we found that MIN6 pancreatic β-cells with stable knockdown of Nrf2 (Nrf2-KD) by lentiviral shRNA andmore » pancreatic islets isolated from Nrf2-knockout (Nrf2−/−) mice exhibited reduced expression of several antioxidant and detoxification enzymes in response to acute iAs{sup 3+} exposure. As a result, Nrf2-KD MIN6 cells and Nrf2−/− islets were more susceptible to iAs{sup 3+} and monomethylarsonous acid (MMA{sup 3+})-induced cell damage, as measured by decreased cell viability, augmented apoptosis and morphological change. Pretreatment of MIN6 cells with Nrf2 activator tert-butylhydroquinone protected the cells from iAs{sup 3+}-induced cell damage in an Nrf2-dependent fashion. In contrast, antioxidant N‐acetyl cysteine protected Nrf2-KD MIN6 cells against acute cytotoxicity of iAs{sup 3+}. The present study demonstrates that Nrf2-mediated antioxidant response is critical in the pancreatic β-cell defense mechanism against acute cytotoxicity by arsenic. The findings here, combined with our previous results on the inhibitory effect of antioxidants on ROS signaling and GSIS, suggest that Nrf2 plays paradoxical roles in pancreatic β-cell dysfunction induced by environmental arsenic exposure. -- Highlights: ► Lack of Nrf2 reduced expression of antioxidant genes induced by iAs{sup 3+} in β-cells. ► Deficiency of Nrf2 in

  14. Modulation of Nrf2/Keap1 system by Wasabi 6-methylthiohexyl isothiocyanate in ARE-mediated NQO1 expression.

    PubMed

    Korenori, Yoshimi; Tanigawa, Shunsuke; Kumamoto, Takuma; Qin, Si; Daikoku, Yosuke; Miyamori, Koji; Nagai, Masashi; Hou, De-Xing

    2013-05-01

    6-Methylthiohexyl isothiocyanate (6-MTITC), one of the major bioactive ingredients in Japanese Wasabi, has revealed cytoprotective and cancer chemopreventive effects. This study aims to clarify the molecular mechanisms how 6-MTITC modulates nuclear factor E2-related factor 2 (Nrf2)/Kelchlike ECH-associating protein 1 (Keap1) system in antioxidant-responsive element (ARE)-mediated nicotinamide adenine dinucleotide phosphate (NADP): quinone oxidoreductase 1 (NQO1) expression. HepG2 cells were treated with 6-MTITC with varying time and dose. NQO1, Nrf2, and Keap1 proteins were detected by Western blotting. ARE transactivation was detected by electrophilic mobility shift assay and reporter gene assay. Nuclear localization of Nrf2 was determined by immunocytochemistry assay. Ubiquitination of Nrf2 and Keap1 was detected using immunoprecipitation after treatment with MG132. Small interfering RNA was used to knockdown Nrf2 or Keap1. The results revealed that 6-MTITC modulated Nrf2/ARE pathway by stimulating Keap1 modification, and inhibiting Nrf2 ubiquitination and protein turnover. These actions finally increased nuclear Nrf2 accumulation and ARE-binding activity. Moreover, silencing Nrf2 markedly reduced ARE-driven activity induced by 6-MTITC. 6-MTITC modulated ARE-driven NQO1 expression by stabilizing Nrf2 with enhanced Keap1 modification and decreased Nrf2 degradation. © 2013 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  15. Protective effects of nuclear factor erythroid 2-related factor 2 on whole body heat stress-induced oxidative damage in the mouse testis.

    PubMed

    Li, Yansen; Huang, Yi; Piao, Yuanguo; Nagaoka, Kentaro; Watanabe, Gen; Taya, Kazuyoshi; Li, ChunMei

    2013-03-21

    Whole body heat stress had detrimental effect on male reproductive function. It's known that the nuclear factor erythroid 2-related factor 2 (Nrf2) activates expression of cytoprotective genes to enable cell adaptation to protect against oxidative stress. However, it's still unclear about the exactly effects of Nrf2 on the testis. Here, we investigate the protective effect of Nrf2 on whole body heat stress-induced oxidative damage in mouse testis. Male mice were exposed to the elevated ambient temperature (42°C) daily for 2 h. During the period of twelve consecutive days, mice were sacrificed on days 1, 2, 4, 8 and 12 immediately following heat exposure. Testes weight, enzymatic antioxidant activities and concentrations of malondialdehyde (MDA) and glutathione (GSH) in the testes were determined and immunohistochemical detection of Nrf2 protein and mRNA expression of Nrf2-regulated genes were analyzed to assess the status of Nrf2-antioxidant system. Heat-exposed mice presented significant increases in rectal, scrotal surface and body surface temperature. The concentrations of cortisol and testosterone in serum fluctuated with the number of exposed days. There were significant decrease in testes weight and relative testes weight on day 12 compared with those on other days, but significant increases in catalase (CAT) activity on day 1 and GSH level on day 4 compared with control group. The activities of total superoxide dismutase (T-SOD) and copper-zinc SOD (CuZn-SOD) increased significantly on days 8 and 12. Moreover, prominent nuclear accumulation of Nrf2 protein was observed in Leydig cells on day 2, accompanying with up-regulated mRNA levels of Nrf2-regulated genes such as Nrf2, heme oxygenase 1 (HO-1), γ-Glutamylcysteine synthetase (GCLC) and NAD (P) H: quinone oxidoreductase 1 (NQO1)) in heat-treated groups. These results suggest that Nrf2 displayed nuclear accumulation and protective activity in the process of heat treated-induced oxidative stress in mouse

  16. Protective effects of nuclear factor erythroid 2-related factor 2 on whole body heat stress-induced oxidative damage in the mouse testis

    PubMed Central

    2013-01-01

    Background Whole body heat stress had detrimental effect on male reproductive function. It's known that the nuclear factor erythroid 2-related factor 2 (Nrf2) activates expression of cytoprotective genes to enable cell adaptation to protect against oxidative stress. However, it’s still unclear about the exactly effects of Nrf2 on the testis. Here, we investigate the protective effect of Nrf2 on whole body heat stress-induced oxidative damage in mouse testis. Methods Male mice were exposed to the elevated ambient temperature (42°C) daily for 2 h. During the period of twelve consecutive days, mice were sacrificed on days 1, 2, 4, 8 and 12 immediately following heat exposure. Testes weight, enzymatic antioxidant activities and concentrations of malondialdehyde (MDA) and glutathione (GSH) in the testes were determined and immunohistochemical detection of Nrf2 protein and mRNA expression of Nrf2-regulated genes were analyzed to assess the status of Nrf2-antioxidant system. Results Heat-exposed mice presented significant increases in rectal, scrotal surface and body surface temperature. The concentrations of cortisol and testosterone in serum fluctuated with the number of exposed days. There were significant decrease in testes weight and relative testes weight on day 12 compared with those on other days, but significant increases in catalase (CAT) activity on day 1 and GSH level on day 4 compared with control group. The activities of total superoxide dismutase (T-SOD) and copper-zinc SOD (CuZn-SOD) increased significantly on days 8 and 12. Moreover, prominent nuclear accumulation of Nrf2 protein was observed in Leydig cells on day 2, accompanying with up-regulated mRNA levels of Nrf2-regulated genes such as Nrf2, heme oxygenase 1 (HO-1), γ-Glutamylcysteine synthetase (GCLC) and NAD (P) H: quinone oxidoreductase 1 (NQO1)) in heat-treated groups. Conclusions These results suggest that Nrf2 displayed nuclear accumulation and protective activity in the process of heat

  17. The C-Terminal Domain of Nrf1 Negatively Regulates the Full-Length CNC-bZIP Factor and Its Shorter Isoform LCR-F1/Nrf1β; Both Are Also Inhibited by the Small Dominant-Negative Nrf1γ/δ Isoforms that Down-Regulate ARE-Battery Gene Expression

    PubMed Central

    Zhang, Yiguo; Qiu, Lu; Li, Shaojun; Xiang, Yuancai; Chen, Jiayu; Ren, Yonggang

    2014-01-01

    The C-terminal domain (CTD, aa 686–741) of nuclear factor-erythroid 2 p45-related factor 1 (Nrf1) shares 53% amino acid sequence identity with the equivalent Neh3 domain of Nrf2, a homologous transcription factor. The Neh3 positively regulates Nrf2, but whether the Neh3-like (Neh3L) CTD of Nrf1 has a similar role in regulating Nrf1-target gene expression is unknown. Herein, we report that CTD negatively regulates the full-length Nrf1 (i.e. 120-kDa glycoprotein and 95-kDa deglycoprotein) and its shorter isoform LCR-F1/Nrf1β (55-kDa). Attachment of its CTD-adjoining 112-aa to the C-terminus of Nrf2 yields the chimaeric Nrf2-C112Nrf1 factor with a markedly decreased activity. Live-cell imaging of GFP-CTD reveals that the extra-nuclear portion of the fusion protein is allowed to associate with the endoplasmic reticulum (ER) membrane through the amphipathic Neh3L region of Nrf1 and its basic c-tail. Thus removal of either the entire CTD or the essential Neh3L portion within CTD from Nrf1, LCR-F1/Nrf1β and Nrf2-C112Nrf1, results in an increase in their transcriptional ability to regulate antioxidant response element (ARE)-driven reporter genes. Further examinations unravel that two smaller isoforms, 36-kDa Nrf1γ and 25-kDa Nrf1δ, act as dominant-negative inhibitors to compete against Nrf1, LCR-F1/Nrf1β and Nrf2. Relative to Nrf1, LCR-F1/Nrf1β is a weak activator, that is positively regulated by its Asn/Ser/Thr-rich (NST) domain and acidic domain 2 (AD2). Like AD1 of Nrf1, both AD2 and NST domain of LCR-F1/Nrf1β fused within two different chimaeric contexts to yield Gal4D:Nrf1β607 and Nrf1β:C270Nrf2, positively regulate their transactivation activity of cognate Gal4- and Nrf2-target reporter genes. More importantly, differential expression of endogenous ARE-battery genes is attributable to up-regulation by Nrf1 and LCR-F1/Nrf1β and down-regulation by Nrf1γ and Nrf1δ. PMID:25290918

  18. The C-terminal domain of Nrf1 negatively regulates the full-length CNC-bZIP factor and its shorter isoform LCR-F1/Nrf1β; both are also inhibited by the small dominant-negative Nrf1γ/δ isoforms that down-regulate ARE-battery gene expression.

    PubMed

    Zhang, Yiguo; Qiu, Lu; Li, Shaojun; Xiang, Yuancai; Chen, Jiayu; Ren, Yonggang

    2014-01-01

    The C-terminal domain (CTD, aa 686-741) of nuclear factor-erythroid 2 p45-related factor 1 (Nrf1) shares 53% amino acid sequence identity with the equivalent Neh3 domain of Nrf2, a homologous transcription factor. The Neh3 positively regulates Nrf2, but whether the Neh3-like (Neh3L) CTD of Nrf1 has a similar role in regulating Nrf1-target gene expression is unknown. Herein, we report that CTD negatively regulates the full-length Nrf1 (i.e. 120-kDa glycoprotein and 95-kDa deglycoprotein) and its shorter isoform LCR-F1/Nrf1β (55-kDa). Attachment of its CTD-adjoining 112-aa to the C-terminus of Nrf2 yields the chimaeric Nrf2-C112Nrf1 factor with a markedly decreased activity. Live-cell imaging of GFP-CTD reveals that the extra-nuclear portion of the fusion protein is allowed to associate with the endoplasmic reticulum (ER) membrane through the amphipathic Neh3L region of Nrf1 and its basic c-tail. Thus removal of either the entire CTD or the essential Neh3L portion within CTD from Nrf1, LCR-F1/Nrf1β and Nrf2-C112Nrf1, results in an increase in their transcriptional ability to regulate antioxidant response element (ARE)-driven reporter genes. Further examinations unravel that two smaller isoforms, 36-kDa Nrf1γ and 25-kDa Nrf1δ, act as dominant-negative inhibitors to compete against Nrf1, LCR-F1/Nrf1β and Nrf2. Relative to Nrf1, LCR-F1/Nrf1β is a weak activator, that is positively regulated by its Asn/Ser/Thr-rich (NST) domain and acidic domain 2 (AD2). Like AD1 of Nrf1, both AD2 and NST domain of LCR-F1/Nrf1β fused within two different chimaeric contexts to yield Gal4D:Nrf1β607 and Nrf1β:C270Nrf2, positively regulate their transactivation activity of cognate Gal4- and Nrf2-target reporter genes. More importantly, differential expression of endogenous ARE-battery genes is attributable to up-regulation by Nrf1 and LCR-F1/Nrf1β and down-regulation by Nrf1γ and Nrf1δ.

  19. Interplay between VEGF and Nrf2 regulates angiogenesis due to intracranial venous hypertension.

    PubMed

    Li, Liwen; Pan, Hao; Wang, Handong; Li, Xiang; Bu, Xiaomin; Wang, Qiang; Gao, Yongyue; Wen, Guodao; Zhou, Yali; Cong, Zixiang; Yang, Youqing; Tang, Chao; Liu, Zhengwei

    2016-11-21

    Venous hypertension(VH) plays an important role in the pathogenesis of cerebral arteriovenous malformations (AVMs) and is closely associated with the HIF-1α/VEGF signaling pathway. Nuclear factor erythroid 2-related factor 2(Nrf2) significantly influences angiogenesis; however, the interplay between Nrf2 and VEGF under VH in brain AVMs remains unclear. Therefore, our study aimed to investigate the interplay between Nrf2 and VEGF due to VH in brain AVMs. Immunohistochemistry indicated that Nrf2 and VEGF were highly expressed in human brain AVM tissues. In vivo, we established a VH model in both wild-type (WT) and siRNA-mediated Nrf2 knockdown rats. VH significantly increased the expression of Nrf2 and VEGF. Loss of Nrf2 markedly inhibited the upregulation of VEGF, as determined by Western blot analysis and qRT-PCR. In vitro, primary brain microvascular endothelial cells (BMECs) were isolated from WT and Nrf2 -/- mice, and a VEGF-Nrf2 positive feed-back loop was observed in BMECs. By trans well assay and angiogenesis assay, Nrf2 knockout significantly inhibited the migration and vascular tube formation of BMECs. These findings suggest that the interplay between Nrf2 and VEGF can contribute to VH-induced angiogenesis in brain AVMs pathogenesis.

  20. Eriodictyol-7-O-glucoside activates Nrf2 and protects against cerebral ischemic injury

    DOE Office of Scientific and Technical Information (OSTI.GOV)

    Jing, Xu; Ren, Dongmei; Wei, Xinbing

    Stroke is a complex disease that may involve oxidative stress-related pathways in its pathogenesis. The nuclear factor erythroid-2-related factor 2/antioxidant response element (Nrf2/ARE) pathway plays an important role in inducing phase II detoxifying enzymes and antioxidant proteins and thus has been considered a potential target for neuroprotection in stroke. The aim of the present study was to determine whether eriodictyol-7-O-glucoside (E7G), a novel Nrf2 activator, can protect against cerebral ischemic injury and to understand the role of the Nrf2/ARE pathway in neuroprotection. In primary cultured astrocytes, E7G increased the nuclear localization of Nrf2 and induced the expression of the Nrf2/ARE-dependentmore » genes. Exposure of astrocytes to E7G provided protection against oxygen and glucose deprivation (OGD)-induced oxidative insult. The protective effect of E7G was abolished by RNA interference-mediated knockdown of Nrf2 expression. In vivo administration of E7G in a rat model of focal cerebral ischemia significantly reduced the amount of brain damage and ameliorated neurological deficits. These data demonstrate that activation of Nrf2/ARE signaling by E7G is directly associated with its neuroprotection against oxidative stress-induced ischemic injury and suggest that targeting the Nrf2/ARE pathway may be a promising approach for therapeutic intervention in stroke. - Highlights: • E7G activates Nrf2 in astrocytes. • E7G stimulates expression of Nrf2-mediated cytoprotective proteins in astrocytes. • E7G protects astrocytes against OGD-induced cell death and apoptosis. • The neuroprotective effect of E7G involves the Nrf2/ARE pathway. • E7G protects rats against cerebral ischemic injury.« less

  1. Oxidative stress and dysfunctional NRF2 underlie pachyonychia congenita phenotypes

    PubMed Central

    Kerns, Michelle L.; Hakim, Jill M.C.; Lu, Rosemary G.; Guo, Yajuan; Berroth, Andreas; Kaspar, Roger L.

    2016-01-01

    Palmoplantar keratoderma (PPK) are debilitating lesions that arise in individuals with pachyonychia congenita (PC) and feature upregulation of danger-associated molecular patterns and skin barrier regulators. The defining features of PC-associated PPK are reproduced in mice null for keratin 16 (Krt16), which is commonly mutated in PC patients. Here, we have shown that PPK onset is preceded by oxidative stress in footpad skin of Krt16–/– mice and correlates with an inability of keratinocytes to sustain nuclear factor erythroid–derived 2 related factor 2–dependent (NRF2-dependent) synthesis of the cellular antioxidant glutathione (GSH). Additionally, examination of plantar skin biopsies from individuals with PC confirmed the presence of high levels of hypophosphorylated NRF2 in lesional tissue. In Krt16–/– mice, genetic ablation of Nrf2 worsened spontaneous skin lesions and accelerated PPK development in footpad skin. Hypoactivity of NRF2 in Krt16–/– footpad skin correlated with decreased levels or activity of upstream NRF2 activators, including PKCδ, receptor for activated C kinase 1 (RACK1), and p21. Topical application of the NRF2 activator sulforaphane to the footpad of Krt16–/– mice prevented the development of PPK and normalized redox balance via regeneration of GSH from existing cellular pools. Together, these findings point to oxidative stress and dysfunctional NRF2 as contributors to PPK pathogenesis, identify K16 as a regulator of NRF2 activation, and suggest that pharmacological activation of NRF2 should be further explored for PC treatment. PMID:27183391

  2. Protective Role of Nuclear Factor E2-Related Factor 2 against Acute Oxidative Stress-Induced Pancreatic β-Cell Damage

    PubMed Central

    Fu, Jingqi; Zheng, Hongzhi; Wang, Huihui; Yang, Bei; Zhao, Rui; Lu, Chunwei; Liu, Zhiyuan; Hou, Yongyong; Xu, Yuanyuan; Zhang, Qiang; Qu, Weidong; Pi, Jingbo

    2015-01-01

    Oxidative stress is implicated in the pathogenesis of pancreatic β-cell dysfunction that occurs in both type 1 and type 2 diabetes. Nuclear factor E2-related factor 2 (NRF2) is a master regulator in the cellular adaptive response to oxidative stress. The present study found that MIN6 β-cells with stable knockdown of Nrf2 (Nrf2-KD) and islets isolated from Nrf2-knockout mice expressed substantially reduced levels of antioxidant enzymes in response to a variety of stressors. In scramble MIN6 cells or wild-type islets, acute exposure to oxidative stressors, including hydrogen peroxide (H2O2) and S-nitroso-N-acetylpenicillamine, resulted in cell damage as determined by decrease in cell viability, reduced ATP content, morphology changes of islets, and/or alterations of apoptotic biomarkers in a concentration- and/or time-dependent manner. In contrast, silencing of Nrf2 sensitized MIN6 cells or islets to the damage. In addition, pretreatment of MIN6 β-cells with NRF2 activators, including CDDO-Im, dimethyl fumarate (DMF), and tert-butylhydroquinone (tBHQ), protected the cells from high levels of H2O2-induced cell damage. Given that reactive oxygen species (ROS) are involved in regulating glucose-stimulated insulin secretion (GSIS) and persistent activation of NRF2 blunts glucose-triggered ROS signaling and GSIS, the present study highlights the distinct roles that NRF2 may play in pancreatic β-cell dysfunction that occurs in different stages of diabetes. PMID:25949772

  3. Are Astrocytes the Predominant Cell Type for Activation of Nrf2 in Aging and Neurodegeneration?

    PubMed Central

    2017-01-01

    Nuclear factor erythroid 2-related factor 2 (Nrf2) is a transcription factor that regulates hundreds of antioxidant genes, and is activated in response to oxidative stress. Given that many neurodegenerative diseases including Alzheimer’s disease, Parkinson’s disease, amyotrophic lateral sclerosis, Huntington’s disease and multiple sclerosis are characterised by oxidative stress, Nrf2 is commonly activated in these diseases. Evidence demonstrates that Nrf2 activity is repressed in neurons in vitro, and only cultured astrocytes respond strongly to Nrf2 inducers, leading to the interpretation that Nrf2 signalling is largely restricted to astrocytes. However, Nrf2 activity can be observed in neurons in post-mortem brain tissue and animal models of disease. Thus this interpretation may be false, and a detailed analysis of the cell type expression of Nrf2 in neurodegenerative diseases is required. This review describes the evidence for Nrf2 activation in each cell type in prominent neurodegenerative diseases and normal aging in human brain and animal models of neurodegeneration, the response to pharmacological and genetic modulation of Nrf2, and clinical trials involving Nrf2-modifying drugs. PMID:28820437

  4. Effects of trigonelline inhibition of the Nrf2 transcription factor in vitro on Echinococcus granulosus.

    PubMed

    Qin, Wenjuan; Guan, Dongfang; Ma, Rongji; Yang, Rentan; Xing, Guoqiang; Shi, Hongjuan; Tang, Guangyao; Li, Jiajie; Lv, Hailong; Jiang, Yufeng

    2017-08-01

    The aim of this study was to investigate the impact of trigonelline (TRG) on Echinococcus granulosus, and to explore the inhibition impact of nuclear factor erythroid-2-related factor 2 (Nrf2) signaling pathway on E. granulosus protoscoleces. Echinococcus granulosus protoscoleces were incubated with various concentrations of TRG, and then Nrf2 protein expression and its localization in protoscoleces were detected by western blot analysis and immunofluorescence assay, respectively. Reactive oxygen species (ROS) level in protoscoleces was measured using ROS detection kit. Caspase-3 activity was measured using a caspase-3 activity assay kit, and NAD(P)H quinone oxidoreductase (NQO)-1 and heme oxygenase (HO)-1 activities in protoscoleces were measured by ELISA. The effect of TRG on protoscoleces viability was investigated using 0.1% eosin staining, and ultrastructural alterations in protoscoleces were examined by scanning electron microscopy (SEM). Immunolocalization experiment clearly showed that Nrf2 protein was predominantly present in cells of protoscoleces. TRG treatment reduced NQO-1 and HO-1 activities in protoscoleces, but could increase ROS level at early time. Protoscoleces could not survive when treated with 250 μM TRG for 12 days. SEM results showed that TRG-treated protoscoleces presented damage in the protoscoleces region, including hook deformation, lesions, and digitiform protuberance. Nrf2 protein expression was significantly decreased and caspase-3 activity was clearly increased in protoscoleces treated with TRG for 24 and 48 h, respectively, when compared with that in controls (P < 0.05). Our results demonstrated that TRG had scolicidal activity against E. granulosus protoscoleces. Nrf2 protein was mainly expressed in the cells and TRG could efficiently inhibit the Nrf2 signaling pathway in E. granulosus. © The Author 2017. Published by Oxford University Press on behalf of the Institute of Biochemistry and Cell Biology, Shanghai Institutes for

  5. NRF2, cancer and calorie restriction.

    PubMed

    Martín-Montalvo, A; Villalba, J M; Navas, P; de Cabo, R

    2011-02-03

    The transcription factor NF-E2-related factor (NRF2) is a key regulator of several enzymatic pathways, including cytoprotective enzymes in highly metabolic organs. In this review, we summarize the ongoing research related to NRF2 activity in cancer development, focusing on in vivo studies using NRF2 knockout (KO) mice, which have helped in defining the crucial role of NRF2 in chemoprevention. The lower cancer protection observed in NRF2 KO mice under calorie restriction (CR) suggests that most of the beneficial effects of CR on the carcinogenesis process are likely mediated by NRF2. We propose that future interventions in cancer treatment would be carried out through the activation of NRF2 in somatic cells, which will lead to a delay or prevention of the onset of some forms of human cancers, and subsequently an extension of health- and lifespan.

  6. MDM2 controls NRF2 antioxidant activity in prevention of diabetic kidney disease.

    PubMed

    Guo, Weiying; Tian, Dan; Jia, Ye; Huang, Wenlin; Jiang, Mengnan; Wang, Junnan; Sun, Weixia; Wu, Hao

    2018-04-26

    Oxidative stress and P53 contribute to the pathogenesis of diabetic kidney disease (DKD). Nuclear factor erythroid 2-related factor 2 (NRF2) is a master regulator of cellular antioxidant defense system, is negatively regulated by P53 and prevents DKD. Recent findings revealed an important role of mouse double minute 2 (MDM2) in protection against DKD. However, the mechanism remained unclear. We hypothesized that MDM2 enhances NRF2 antioxidant signaling in DKD given that MDM2 is a key negative regulator of P53. The MDM2 inhibitor nutlin3a elevated renal P53, inhibited NRF2 signaling and induced oxidative stress, inflammation, fibrosis, DKD-like renal pathology and albuminuria in the wild-type (WT) non-diabetic mice. These effects exhibited more prominently in nutlin3a-treated WT diabetic mice. Interestingly, nutlin3a failed to induce greater renal injuries in the Nrf2 knockout (KO) mice under both the diabetic and non-diabetic conditions, indicating that NRF2 predominantly mediates MDM2's action. On the contrary, P53 inhibition by pifithrin-α activated renal NRF2 signaling and the expression of Mdm2, and attenuated DKD in the WT diabetic mice, but not in the Nrf2 KO diabetic mice. In high glucose-treated mouse mesangial cells, P53 gene silencing completely abolished nutlin3a's inhibitory effect on NRF2 signaling. The present study demonstrates for the first time that MDM2 controls renal NRF2 antioxidant activity in DKD via inhibition of P53, providing MDM2 activation and P53 inhibition as novel strategies in the management of DKD. Copyright © 2018 Elsevier B.V. All rights reserved.

  7. Deletion of Nrf2 reduces skeletal mechanical properties and decreases load-driven bone formation.

    PubMed

    Sun, Yong-Xin; Li, Lei; Corry, Kylie A; Zhang, Pei; Yang, Yang; Himes, Evan; Mihuti, Cristina Layla; Nelson, Cecilia; Dai, Guoli; Li, Jiliang

    2015-05-01

    Nuclear factor erythroid 2-related factor 2 (Nrf2) is a transcription factor expressed in many cell types, including osteoblasts, osteocytes, and osteoclasts. Nrf2 has been considered a master regulator of cytoprotective genes against oxidative and chemical insults. The lack of Nrf2 can induce pathologies in multiple organs. The aim of this study was to investigate the role of Nrf2 in load-driven bone metabolism using Nrf2 knockout (KO) mice. Compared to age-matched littermate wild-type controls, Nrf2 KO mice have significantly lowered femoral bone mineral density (-7%, p<0.05), bone formation rate (-40%, p<0.05), as well as ultimate force (-11%, p<0.01). The ulna loading experiment showed that Nrf2 KO mice were less responsive than littermate controls, as indicated by reduction in relative mineralizing surface (rMS/BS, -69%, p<0.01) and relative bone formation rate (rBFR/BS, -84%, p<0.01). Furthermore, deletion of Nrf2 suppressed the load-driven gene expression of antioxidant enzymes and Wnt5a in cultured primary osteoblasts. Taken together, the results suggest that the loss-of-function mutation of Nrf2 in bone impairs bone metabolism and diminishes load-driven bone formation. Copyright © 2015 Elsevier Inc. All rights reserved.

  8. Nrf2 inhibits oxaliplatin-induced peripheral neuropathy via protection of mitochondrial function.

    PubMed

    Yang, Yang; Luo, Lan; Cai, Xueting; Fang, Yuan; Wang, Jiaqi; Chen, Gang; Yang, Jie; Zhou, Qian; Sun, Xiaoyan; Cheng, Xiaolan; Yan, Huaijiang; Lu, Wuguang; Hu, Chunping; Cao, Peng

    2018-05-20

    Oxaliplatin-induced peripheral neuropathy (OIPN) is a severe, dose-limiting toxicity associated with cancer chemotherapy. The efficacy of antioxidant administration in OIPN is debatable, as the promising preliminary results obtained with a number of antioxidants have not been confirmed in larger clinical trials. Besides its antioxidant activity, the transcription factor, nuclear factor-erythroid 2 (NF-E2) p45-related factor 2 (Nrf2) plays a crucial role in the maintenance of mitochondrial homeostasis, and mitochondrial dysfunction is a key contributor to OIPN. Here, we have investigated the protective properties of Nrf2 in OIPN. Nrf2 -/- mice displayed severe mechanical allodynia and cold sensitivity and thus experienced increased peripheral nervous system injury compared to Nrf2 +/+ mice. Furthermore, Nrf2 knockout aggravated oxaliplatin-induced reactive oxygen species production, decreased the mitochondrial membrane potential, led to abnormal intracellular calcium levels, and induced cytochrome c-related apoptosis and overexpression of the TRP protein family. Sulforaphane-induced activation of the Nrf2 signaling pathway alleviated morphological alterations, mitochondrial dysfunction in dorsal root ganglion neurons, and nociceptive sensations in mice. Our findings reveal that Nrf2 may play a critical role in ameliorating OIPN, through protection of mitochondrial function by alleviating oxidative stress and inhibiting TRP protein family expression. This suggests that pharmacological or therapeutic activation of Nrf2 may be used to prevent or slow down the progression of OIPN. Copyright © 2018 Elsevier Inc. All rights reserved.

  9. Nrf2-peroxiredoxin I axis in polymorphous adenocarcinoma is associated with low matrix metalloproteinase 2 level.

    PubMed

    Brod, J M; Demasi, Ana Paula Dias; Montalli, V A; Teixeira, L N; Furuse, C; Aguiar, M C; Soares, A B; Sperandio, M; Araujo, V C

    2017-12-01

    Polymorphous adenocarcinoma (PAC) is a malignant epithelial neoplasm that affects almost exclusively the minor salivary glands, generally described as having a relatively good prognosis. Aberrant nuclear factor erythroid 2 (NF-E2)-related factor (Nrf2) activation in tumor cells has been associated with induction of antioxidant enzymes, such as peroxiredoxin I (Prx I) and increased matrix metalloproteinase (MMP) expression. In this context, the aim of the present study was to evaluate the expression of Nrf2 and correlate it with Prx I and MMP-2 secretion in PAC. Thirty-one cases of PAC from oral biopsies were selected and immunohistochemically analyzed for Nrf2 and Prx I. MMP-2 quantification was performed on primary cell cultures derived from PAC. Oral squamous cell carcinoma (OSCC) cell cultures were used as control. A high immunoexpression of Nrf2 was observed in both the cytoplasm and the nucleus of neoplastic cells from PAC. Nuclear staining for Nrf2 suggested its activation in the majority of the PAC cells, which was confirmed by the high expression of its target gene, Prx I. Quantification of MMP-2 secretion showed lower levels in PAC cell cultures when compared to OSCC cell cultures (p < 0.05). In conclusion, although Nrf2 overexpression has been frequently associated with high-grade malignancies, such relationship is not infallible and, in fact, the opposite may occur in low-grade tumors, such as PAC of minor salivary glands.

  10. Activation of KGFR-Akt-mTOR-Nrf2 signaling protects human retinal pigment epithelium cells from Ultra-violet.

    PubMed

    Hu, Haitao; Hao, Lanxiang; Tang, Chunzhou; Zhu, Yunxi; Jiang, Qin; Yao, Jin

    2018-01-15

    Ultra-violet (UV) radiation causes oxidative injuries to human retinal pigment epithelium (RPE) cells. We tested the potential effect of keratinocyte growth factor (KGF) against the process. KGF receptor (KGFR) is expressed in ARPE-19 cells and primary human RPE cells. Pre-treatment with KGF inhibited UV-induced reactive oxygen species (ROS) production and RPE cell death. KGF activated nuclear-factor-E2-related factor 2 (Nrf2) signaling in RPE cells, causing Nrf2 Ser-40 phosphorylation, stabilization and nuclear translocation as well as expression of Nrf2-dependent genes (HO1, NOQ1 and GCLC). Nrf2 knockdown (by targeted shRNAs) or S40T mutation almost reversed KGF-induced RPE cell protection against UV. Further studies demonstrated that KGF activated KGFR-Akt-mTORC1 signaling to mediate downstream Nrf2 activation. KGFR shRNA or Akt-mTORC1 inhibition not only blocked KGF-induced Nrf2 Ser-40 phosphorylation and activation, but also nullified KGF-mediated RPE cell protection against UV. We conclude that KGF-KGFR activates Akt-mTORC1 downstream Nrf2 signaling to protect RPE cells from UV radiation. Copyright © 2017 Elsevier Inc. All rights reserved.

  11. Naphthazarin protects against glutamate-induced neuronal death via activation of the Nrf2/ARE pathway

    DOE Office of Scientific and Technical Information (OSTI.GOV)

    Son, Tae Gen; Kawamoto, Elisa M.; Yu, Qian-Sheng

    2013-04-19

    Highlights: •Naphthazarin activates the Nrf2/ARE pathway. •Naphthazarin induces Nrf2-driven genes in neurons and astrocytes. •Naphthazarin protects neurons against excitotoxicity. -- Abstract: Nuclear factor E2-related factor 2 (Nrf2)/antioxidant response element (ARE) pathway is an important cellular stress response pathway involved in neuroprotection. We previously screened several natural phytochemicals and identified plumbagin as a novel activator of the Nrf2/ARE pathway that can protect neurons against ischemic injury. Here we extended our studies to natural and synthetic derivatives of plumbagin. We found that 5,8-dimethoxy-1,4-naphthoquinone (naphthazarin) is a potent activator of the Nrf2/ARE pathway, up-regulates the expression of Nrf2-driven genes in primary neuronal andmore » glial cultures, and protects neurons against glutamate-induced excitotoxicity.« less

  12. The nuclear factor (erythroid-derived 2)-like 2 (NRF2) antioxidant response promotes melanocyte viability and reduces toxicity of the vitiligo-inducing phenol monobenzone.

    PubMed

    Arowojolu, Omotayo A; Orlow, Seth J; Elbuluk, Nada; Manga, Prashiela

    2017-07-01

    Vitiligo, characterised by progressive melanocyte death, can be initiated by exposure to vitiligo-inducing phenols (VIPs). VIPs generate oxidative stress in melanocytes and activate the master antioxidant regulator NRF2. While NRF2-regulated antioxidants are reported to protect melanocytes from oxidative stress, the role of NRF2 in the melanocyte response to monobenzone, a clinically relevant VIP, has not been characterised. We hypothesised that activation of NRF2 may protect melanocytes from monobenzone-induced toxicity. We observed that knockdown of NRF2 or NRF2-regulated antioxidants NQO1 and PRDX6 reduced melanocyte viability, but not viability of keratinocytes and fibroblasts, suggesting that melanocytes were preferentially dependent upon NRF2 activity for growth compared to other cutaneous cells. Furthermore, melanocytes activated the NRF2 response following monobenzone exposure and constitutive NRF2 activation reduced monobenzone toxicity, supporting NRF2's role in the melanocyte stress response. In contrast, melanocytes from individuals with vitiligo (vitiligo melanocytes) did not activate the NRF2 response as efficiently. Dimethyl fumarate-mediated NRF2 activation protected normal and vitiligo melanocytes against monobenzone-induced toxicity. Given the contribution of oxidant-antioxidant imbalance in vitiligo, modulation of this pathway may be of therapeutic interest. © 2017 John Wiley & Sons A/S. Published by John Wiley & Sons Ltd.

  13. Nrf2 the rescue: effects of the antioxidative/electrophilic response on the liver.

    PubMed

    Klaassen, Curtis D; Reisman, Scott A

    2010-04-01

    Nuclear factor erythroid 2-related factor 2 (Nrf2) is a transcription factor that positively regulates the basal and inducible expression of a large battery of cytoprotective genes. These gene products include proteins that catalyze reduction reactions (NAD(P)H:quinone oxidoreductase 1, Nqo1), conjugation reactions (glutathione-S-transferases, Gsts and UDP-glucuronosyltransferases, Ugts), as well as the efflux of potentially toxic xenobiotics and xenobiotic conjugates (multidrug resistance-associated proteins, Mrps). The significance of Nrf2 in the liver has been established, as livers of Nrf2-null mice are more susceptible to various oxidative/electrophilic stress-induced pathologies than wild-type mice. In contrast, both pharmacological and genetic models of hepatic Nrf2 activation are protective against oxidative/electrophilic stress. Furthermore, because certain Nrf2-target genes in the liver could affect the distribution, metabolism, and excretion of xenobiotics, the effects of Nrf2 on the kinetics of drugs and other xenobiotics should also be considered, with a special emphasis on metabolism and excretion. Therefore, this review highlights the research that has contributed to the understanding of the importance of Nrf2 in toxicodynamics and toxicokinetics, especially that which pertains to the liver. 2010 Elsevier Inc. All rights reserved.

  14. Induction of Lung GSH and Glutamate Cysteine Ligase by 1,4-phenylenebis(methylene)selenocyanate and its Glutathione Conjugate: Role of Nuclear factor-erythroid 2-Related Factor 2

    PubMed Central

    Emmert, Sans W.; El-Bayoumy, Karam; Das, Arunangshu; Sun, Yuan-Wan; Amin, Shantu; Desai, Dhimant; Aliaga, Cesar; Richie, John P.

    2012-01-01

    The synthetic organoselenium agent 1,4- phenylenebis(methylene)selenocyanate (p-XSC) and its glutathione (GSH) conjugate (p-XSeSG), are potent chemopreventive agents in several preclinical models. p-XSC is also an effective inducer of GSH in mouse lung. Our objectives were to test the hypothesis that GSH induction by p-XSC occurs through upregulation of the rate-limiting GSH biosynthetic enzyme glutamate cysteine ligase (GCL), through activation of antioxidant response elements (ARE) in GCL genes via activation of nuclear factor-erythroid 2-related factor 2 (Nrf2). p-XSC feeding (10 ppm Se) increased GSH (230%) and upregulated the catalytic subunit of GCL (GCLc) (55%), extracellular related kinase (ERK) (220%) and nuclear Nrf2 (610%) in lung but not liver after 14 days in the rat (P<0.05). Similarly, p-XSeSG feeding (10 ppm) induced lung GCLc (88%) and GSH (200%) (P<0.05), while the naturally-occurring selenomethionine had no effect. Both p-XSC and p-XSeSG activated a luciferase reporter in HepG2 ARE reporter cells up to 3-fold for p-XSC and ≥5-fold for p-XSeSG. Luciferase activation by p-XSeSG was associated with enhanced levels of GSH, GCLc and nuclear Nrf2, which were significantly reduced by co-incubation with short interfering RNA targeting Nrf2 (siNrf2). The dependence of GCL induction on Nrf2 was confirmed in Nrf2 deficient mouse embryonic fibroblasts (MEF) where p-XSeSG induced GCL subunits in wildtype, but not Nrf2 deficient cells (p<0.05). These results indicate that p-XSC may act through the Nrf2 pathway in vivo, and that p-XSeSG is the putative metabolite responsible for such activation, thus offering p-XSeSG as a less toxic, yet highly efficacious inducer of GSH. PMID:22542796

  15. Genetic silencing of Nrf2 enhances X-ROS in dysferlin-deficient muscle

    PubMed Central

    Kombairaju, Ponvijay; Kerr, Jaclyn P.; Roche, Joseph A.; Pratt, Stephen J. P.; Lovering, Richard M.; Sussan, Thomas E.; Kim, Jung-Hyun; Shi, Guoli; Biswal, Shyam; Ward, Christopher W.

    2014-01-01

    Oxidative stress is a critical disease modifier in the muscular dystrophies. Recently, we discovered a pathway by which mechanical stretch activates NADPH Oxidase 2 (Nox2) dependent ROS generation (X-ROS). Our work in dystrophic skeletal muscle revealed that X-ROS is excessive in dystrophin-deficient (mdx) skeletal muscle and contributes to muscle injury susceptibility, a hallmark of the dystrophic process. We also observed widespread alterations in the expression of genes associated with the X-ROS pathway and redox homeostasis in muscles from both Duchenne muscular dystrophy patients and mdx mice. As nuclear factor erythroid 2-related factor 2 (Nrf2) plays an essential role in the transcriptional regulation of genes involved in redox homeostasis, we hypothesized that Nrf2 deficiency may contribute to enhanced X-ROS signaling by reducing redox buffering. To directly test the effect of diminished Nrf2 activity, Nrf2 was genetically silenced in the A/J model of dysferlinopathy—a model with a mild histopathologic and functional phenotype. Nrf2-deficient A/J mice exhibited significant muscle-specific functional deficits, histopathologic abnormalities, and dramatically enhanced X-ROS compared to control A/J and WT mice, both with functional Nrf2. Having identified that reduced Nrf2 activity is a negative disease modifier, we propose that strategies targeting Nrf2 activation may address the generalized reduction in redox homeostasis to halt or slow dystrophic progression. PMID:24600403

  16. Fasting Induces Nuclear Factor E2-Related Factor 2 and ATP-Binding Cassette Transporters via Protein Kinase A and Sirtuin-1 in Mouse and Human

    PubMed Central

    Kulkarni, Supriya R.; Donepudi, Ajay C.; Xu, Jialin; Wei, Wei; Cheng, Qiuqiong C.; Driscoll, Maureen V.; Johnson, Delinda A.; Johnson, Jeffrey A.; Li, Xiaoling

    2014-01-01

    Abstract Aims: The purpose of this study was to determine whether 3′-5′-cyclic adenosine monophosphate (cAMP)-protein kinase A (PKA) and Sirtuin-1 (SIRT1) dependent mechanisms modulate ATP-binding Cassette (ABC) transport protein expression. ABC transport proteins (ABCC2–4) are essential for chemical elimination from hepatocytes and biliary excretion. Nuclear factor-E2 related-factor 2 (NRF2) is a transcription factor that mediates ABCC induction in response to chemical inducers and liver injury. However, a role for NRF2 in the regulation of transporter expression in nonchemical models of liver perturbation is largely undescribed. Results: Here we show that fasting increased NRF2 target gene expression through NRF2- and SIRT1–dependent mechanisms. In intact mouse liver, fasting induces NRF2 target gene expression by at least 1.5 to 5-fold. In mouse and human hepatocytes, treatment with 8-Bromoadenosine-cAMP, a cAMP analogue, increased NRF2 target gene expression and antioxidant response element activity, which was decreased by the PKA inhibitor, H-89. Moreover, fasting induced NRF2 target gene expression was decreased in liver and hepatocytes of SIRT1 liver-specific null mice and NRF2-null mice. Lastly, NRF2 and SIRT1 were recruited to MAREs and Antioxidant Response Elements (AREs) in the human ABCC2 promoter. Innovation: Oxidative stress mediated NRF2 activation is well described, yet the influence of basic metabolic processes on NRF2 activation is just emerging. Conclusion: The current data point toward a novel role of nutrient status in regulation of NRF2 activity and the antioxidant response, and indicates that cAMP/PKA and SIRT1 are upstream regulators for fasting-induced activation of the NRF2-ARE pathway. Antioxid. Redox Signal. 20, 15–30. PMID:23725046

  17. Adipose Deficiency of Nrf2 in ob/ob Mice Results in Severe Metabolic Syndrome

    PubMed Central

    Xue, Peng; Hou, Yongyong; Chen, Yanyan; Yang, Bei; Fu, Jingqi; Zheng, Hongzhi; Yarborough, Kathy; Woods, Courtney G.; Liu, Dianxin; Yamamoto, Masayuki; Zhang, Qiang; Andersen, Melvin E.; Pi, Jingbo

    2013-01-01

    Nuclear factor E2–related factor 2 (Nrf2) is a transcription factor that functions as a master regulator of the cellular adaptive response to oxidative stress. Our previous studies showed that Nrf2 plays a critical role in adipogenesis by regulating expression of CCAAT/enhancer-binding protein β and peroxisome proliferator–activated receptor γ. To determine the role of Nrf2 in the development of obesity and associated metabolic disorders, the incidence of metabolic syndrome was assessed in whole-body or adipocyte-specific Nrf2-knockout mice on a leptin-deficient ob/ob background, a model with an extremely positive energy balance. On the ob/ob background, ablation of Nrf2, globally or specifically in adipocytes, led to reduced white adipose tissue (WAT) mass, but resulted in an even more severe metabolic syndrome with aggravated insulin resistance, hyperglycemia, and hypertriglyceridemia. Compared with wild-type mice, WAT of ob/ob mice expressed substantially higher levels of many genes related to antioxidant response, inflammation, adipogenesis, lipogenesis, glucose uptake, and lipid transport. Absence of Nrf2 in WAT resulted in reduced expression of most of these factors at mRNA or protein levels. Our findings support a novel role for Nrf2 in regulating adipose development and function, by which Nrf2 controls the capacity of WAT expansion and insulin sensitivity and maintains glucose and lipid homeostasis. PMID:23238296

  18. Involvement of the p62/NRF2 signal transduction pathway on erythrophagocytosis.

    PubMed

    Santarino, Inês B; Viegas, Michelle S; Domingues, Neuza S; Ribeiro, Ana M; Soares, Miguel P; Vieira, Otília V

    2017-07-19

    Erythrophagocytosis, the phagocytic removal of damaged red blood cells (RBC), and subsequent phagolysosome biogenesis are important processes in iron/heme metabolism and homeostasis. Phagolysosome biogenesis implies the interaction of nascent phagosomes with endocytic compartments and also autophagy effectors. Here, we report that besides recruitment of microtubule-associated protein-1-light chain 3 (LC3), additional autophagy machinery such as sequestosome 1 (p62) is also acquired by single-membrane phagosomes at very early stages of the phagocytic process and that its acquisition is very important to the outcome of the process. In bone marrow-derived macrophages (BMDM) silenced for p62, RBC degradation is inhibited. P62, is also required for nuclear translocation and activation of the transcription factor Nuclear factor E2-related Factor 2 (NRF2) during erythrophagocytosis. Deletion of the Nrf2 allele reduces p62 expression and compromises RBC degradation. In conclusion, we reveal that erythrophagocytosis relies on an interplay between p62 and NRF2, potentially acting as protective mechanism to maintain reactive oxygen species at basal levels and preserve macrophage homeostasis.

  19. Structure activity relationship of phenolic diterpenes from Salvia officinalis as activators of the nuclear factor E2-related factor 2 pathway

    PubMed Central

    Fischedick, Justin T; Standiford, Miranda; Johnson, Delinda A.; Johnson, Jeffrey A.

    2013-01-01

    Nuclear factor E2-related factor 2 (Nrf2) is a transcription factor known to activate cytoprotective genes which may be useful in the treatment of neurodegenerative disease. In order to better understand the structure activity relationship of phenolic diterpenes from Salvia officinalis L., we isolated carnosic acid, carnosol, epirosmanol, rosmanol, 12-methoxy-carnosic acid, sageone, and carnosaldehyde using polyamide column, centrifugal partition chromatography, and semi-preparative high performance liquid chromatography. Isolated compounds were screened in-vitro for their ability to active the Nrf2 and general cellular toxicity using mouse primary cortical cultures. All compounds except 12-methoxy-carnosic acid were able to activate the antioxidant response element. Furthermore both carnosol and carnoasldehyde were able to induce Nrf2-dependent gene expression as well as protect mouse primary cortical neuronal cultures from H2O2 induced cell death. PMID:23507152

  20. Nrf2 regulates cellular behaviors and Notch signaling in oral squamous cell carcinoma cells.

    PubMed

    Fan, Hong; Paiboonrungruan, Chorlada; Zhang, Xinyan; Prigge, Justin R; Schmidt, Edward E; Sun, Zheng; Chen, Xiaoxin

    2017-11-04

    Oxidative stress is known to play a pivotal role in the development of oral squamous cell carcinoma (OSCC). We have demonstrated that activation of the nuclear factor erythroid 2-related factor 2 (Nrf2) signaling pathway has chemopreventive effects against oxidative stress-associated OSCC. However, Nrf2 have dual roles in cancer development; while it prevents carcinogenesis of normal cells, hyperactive Nrf2 also promotes the survival of cancer cells. This study is aimed to understand the function of Nrf2 in regulating cellular behaviors of OSCC cells, and the potential mechanisms through which Nrf2 facilitates OSCC. We established the Nrf2-overexpressing and Nrf2-knockdown OSCC cell lines, and examined the function of Nrf2 in regulating cell proliferation, migration, invasion, cell cycle and colony formation. Our data showed that Nrf2 overexpression promoted cancer phenotypes in OSCC cells, whereas Nrf2 silencing inhibited these phenotypes. In addition, Nrf2 positively regulated Notch signaling pathway in OSCC cells in vitro. Consistent with this observation, Nrf2 activation in Keap1 -/- mice resulted in not only hyperproliferation of squamous epithelial cells in mouse tongue as evidenced by increased expression of PCNA, but also activation of Notch signaling in these cells as evidenced by increased expression of NICD1 and Hes1. In conclusion, Nrf2 regulates cancer behaviors and Notch signaling in OSCC cells. Copyright © 2017 Elsevier Inc. All rights reserved.

  1. The role of nuclear factor E2-Related factor 2 and uncoupling protein 2 in glutathione metabolism: Evidence from an in vivo gene knockout study.

    PubMed

    Chen, Yanyan; Xu, Yuanyuan; Zheng, Hongzhi; Fu, Jingqi; Hou, Yongyong; Wang, Huihui; Zhang, Qiang; Yamamoto, Masayuki; Pi, Jingbo

    2016-09-09

    Nuclear factor E2-related factor 2 (NRF2) and uncoupling protein 2 (UCP2) are indicated to protect from oxidative stress. They also play roles in the homeostasis of glutathione. However, the detailed mechanisms are not well understood. In the present study, we found Nrf2-knockout (Nrf2-KO) mice exhibited altered glutathione homeostasis and reduced expression of various genes involved in GSH biosynthesis, regeneration, utilization and transport in the liver. Ucp2-knockout (Ucp2-KO) mice exhibited altered glutathione homeostasis in the liver, spleen and blood, as well as increased transcript of cystic fibrosis transmembrane conductance regulator in the liver, a protein capable of mediating glutathione efflux. Nrf2-Ucp2-double knockout (DKO) mice showed characteristics of both Nrf2-KO and Ucp2-KO mice. But no significant difference was observed in DKO mice when compared with Nrf2-KO or Ucp2-KO mice, except in blood glutathione levels. These data suggest that ablation of Nrf2 and Ucp2 leads to disrupted GSH balance, which could result from altered expression of genes involved in GSH metabolism. DKO may not evoke more severe oxidative stress than the single gene knockout. Copyright © 2016 Elsevier Inc. All rights reserved.

  2. Lipoicmethylenedioxyphenol Reduces Experimental Atherosclerosis through Activation of Nrf2 Signaling

    PubMed Central

    Ying, Zhekang; Chen, Minjie; Xie, Xiaoyun; Wang, Xiaoke; Kherada, Nisharahmed; Desikan, Rajagopal; Mihai, Georgeta; Burns, Patrick; Sun, Qinghua; Rajagopalan, Sanjay

    2016-01-01

    Objective Oxidative stress is implicated in the pathogenesis of atherosclerosis, and Nrf2 is the transcriptional factor central in cellular antioxidant responses. In the present study, we investigate the effect of a dihydrolipoic acid derivative lipoicmethylenedioxyphenol (LMDP) on the progression of atherosclerosis and test whether its effect on atherosclerosis is mediated by Nrf2. Methods and Results Both magnetic resonance imaging (MRI) scanning and en face analysis reveal that 14 weeks of treatment with LMDP markedly reduced atherosclerotic burden in a rabbit balloon vascular injury model. Myograph analyses show decreased aortic contractile response to phenylephrine and increased aortic response to acetylcholine and insulin in LMDP-treated animals, suggesting that LMDP inhibits atherosclerosis through improving vascular function. A role of Nrf2 signaling in mediating the amelioration of vascular function by LMDP was supported by increased Nrf2 translocation into nuclear and increased expression of Nrf2 target genes. Furthermore, chemotaxis analysis with Boydem chamber shows that leukocytes isolated from LMDP-treated rabbits had reduced chemotaxis, and knock-down of Nrf2 significantly reduced the effect of LMDP on the chemotaxis of mouse macrophages. Conclusion Our results support that LMDP has an anti-atherosclerotic effect likely through activation of Nrf2 signaling and subsequent inhibition of macrophage chemotaxis. PMID:26859892

  3. Lithium Promotes Longevity through GSK3/NRF2-Dependent Hormesis

    PubMed Central

    Castillo-Quan, Jorge Iván; Li, Li; Kinghorn, Kerri J.; Ivanov, Dobril K.; Tain, Luke S.; Slack, Cathy; Kerr, Fiona; Nespital, Tobias; Thornton, Janet; Hardy, John; Bjedov, Ivana; Partridge, Linda

    2016-01-01

    Summary The quest to extend healthspan via pharmacological means is becoming increasingly urgent, both from a health and economic perspective. Here we show that lithium, a drug approved for human use, promotes longevity and healthspan. We demonstrate that lithium extends lifespan in female and male Drosophila, when administered throughout adulthood or only later in life. The life-extending mechanism involves the inhibition of glycogen synthase kinase-3 (GSK-3) and activation of the transcription factor nuclear factor erythroid 2-related factor (NRF-2). Combining genetic loss of the NRF-2 repressor Kelch-like ECH-associated protein 1 (Keap1) with lithium treatment revealed that high levels of NRF-2 activation conferred stress resistance, while low levels additionally promoted longevity. The discovery of GSK-3 as a therapeutic target for aging will likely lead to more effective treatments that can modulate mammalian aging and further improve health in later life. PMID:27068460

  4. The role of nuclear factor E2-Related factor 2 and uncoupling protein 2 in glutathione metabolism: Evidence from an in vivo gene knockout study

    DOE Office of Scientific and Technical Information (OSTI.GOV)

    Chen, Yanyan; The Hamner Institutes for Health Sciences, Research Triangle Park, NC; Xu, Yuanyuan, E-mail: yyxu@cmu.edu.cn

    Nuclear factor E2-related factor 2 (NRF2) and uncoupling protein 2 (UCP2) are indicated to protect from oxidative stress. They also play roles in the homeostasis of glutathione. However, the detailed mechanisms are not well understood. In the present study, we found Nrf2-knockout (Nrf2-KO) mice exhibited altered glutathione homeostasis and reduced expression of various genes involved in GSH biosynthesis, regeneration, utilization and transport in the liver. Ucp2-knockout (Ucp2-KO) mice exhibited altered glutathione homeostasis in the liver, spleen and blood, as well as increased transcript of cystic fibrosis transmembrane conductance regulator in the liver, a protein capable of mediating glutathione efflux. Nrf2-Ucp2-doublemore » knockout (DKO) mice showed characteristics of both Nrf2-KO and Ucp2-KO mice. But no significant difference was observed in DKO mice when compared with Nrf2-KO or Ucp2-KO mice, except in blood glutathione levels. These data suggest that ablation of Nrf2 and Ucp2 leads to disrupted GSH balance, which could result from altered expression of genes involved in GSH metabolism. DKO may not evoke more severe oxidative stress than the single gene knockout. - Highlights: • Nrf2/Ucp2 deficiency leads to alteration of glutathione homeostasis. • Nrf2 regulates expression of genes in glutathione generation and utilization. • Ucp2 affects glutathione metabolism by regulating hepatic efflux of glutathione. • Nrf2 deficiency may not aggravate oxidative stress in Ucp2-deficient mice.« less

  5. Glutathione S-transferase pi expression regulates the Nrf2-dependent response to hormetic diselenides.

    PubMed

    Bartolini, D; Commodi, J; Piroddi, M; Incipini, L; Sancineto, L; Santi, C; Galli, F

    2015-11-01

    Glutathione S-transferase pi (GSTP), a phase II gene downstream of the nuclear factor erythroid 2-related factor 2 (Nrf2)-antioxidant-responsive element (ARE)/electrophile response element (EpRE) transcription pathway, plays a key role in both the signaling and detoxification response to Se-organic compounds with thiol peroxidase activity. We here investigated the role of GSTP on the Nrf2 activation response of cells challenged with a new class of diselenides derived from the basic structure of diphenyl diselenide [(PhSe)2]. These diselenides, and particularly 2,2'-diselenyl dibenzoic acid (DSBA), behave as mild thiol peroxidases leading to a moderate generation of H2O2 and NOx, and signaling of stress-activated and survival-promoting MAPKs, which ultimately control the mitochondrial pathway of apoptosis. Used in murine embryonic fibroblasts (MEFs) and HepG2 human hepatocarcinoma cells to produce submaximal conditions of stress, the diselenide compounds stimulated Nrf2 nuclear translocation and then the transcription of the same Nrf2 gene as well as of GSTP and other phase II genes. This resulted in a higher degree of protection against H2O2 cytotoxicity (hormetic effect). Diselenide toxicity increased in GSTP knockout MEFs by a higher generation of NOx and stress activated protein kinase (SAPK)/JNK activation. A lowered hormetic potential of these cells was observed in association with an abnormal expression and nuclear translocation of Nrf2 protein. Immunoprecipitation and affinity purification experiments revealed the existence of an Nrf2/GSTP complex in MEFs and HepG2 cells. Covalent oligomers of GSTP subunits were observed in DSBA-treated HepG2 cells. In conclusion, GSTP gene expression influences the Nrf2-dependent response to hormetic diselenides. Mechanistic interpretation for this GSTP-dependent effect may include a direct and redox-sensitive interaction of GSTP with Nrf2 protein. Copyright © 2015 Elsevier Inc. All rights reserved.

  6. Silencing Nrf2 impairs glioma cell proliferation via AMPK-activated mTOR inhibition

    DOE Office of Scientific and Technical Information (OSTI.GOV)

    Jia, Yue; Wang, Handong, E-mail: njhdwang@hotmail.com; Wang, Qiang

    Gliomas are the leading cause of death among adults with primary brain malignancies. Treatment for malignant gliomas remains limited, and targeted therapies have been incompletely explored. Nuclear factor erythroid 2-related factor 2 (Nrf2), a key transcription regulator for antioxidant and detoxification enzymes, is abundantly expressed in cancer cells. In this study, the role and mechanism of Nrf2 in cancer cell proliferation was investigated in multiple glioma cell lines. We first evaluated the expression patterns of Nrf2 in four glioma cell lines and found all four cell lines expressed Nrf2, but the highest level was observed in U251 cells. We further evaluatedmore » the biological functions of Nrf2 in U251 glioma cell proliferation by specific inhibition of Nrf2 using short hairpin RNA (shRNA). We found that Nrf2 depletion inhibited glioma cell proliferation. Nrf2 depletion also decreased colony formation in U251 cells stably expressing Nrf2 shRNA compared to scrambled control shRNA. Moreover, suppression of Nrf2 expression could lead to ATP depletion (with concomitant rise in AMP/ATP ratio) and consequently to AMPK-activated mTOR inhibition. Finally, activation of adenosine monophosphate–activated protein kinase (AMPK) by treated with phenformin, an AMPK agonist, can mimic the inhibitory effect of Nrf2 knockdown in U251 cells. In conclusion, our findings will shed light to the role and mechanism of Nrf2 in regulating glioma proliferation via ATP-depletion-induced AMPK activation and consequent mTOR inhibition, a novel insight into our understanding the role and mechanism of Nrf2 in glioma pathoetiology. To our knowledge, this is also the first report to provide a rationale for the implication of cross-linking between Nrf2 and mTOR signaling.« less

  7. Potential drugs which activate nuclear factor E2-related factor 2 signaling to prevent diabetic cardiovascular complications: A focus on fumaric acid esters.

    PubMed

    Zhou, Shanshan; Jin, Jingpeng; Bai, Tao; Sachleben, Leroy R; Cai, Lu; Zheng, Yang

    2015-08-01

    Diabetes and its cardiovascular complications have been a major public health issue. These complications are mainly attributable to a severe imbalance between free radical and reactive oxygen species production and the antioxidant defense systems. Nuclear factor E2-related factor 2 (Nrf2) is a transcription factor that controls the basal and inducible expression of a battery of antioxidant enzyme genes and other cyto-protective phase II detoxifying enzymes. As a result, Nrf2 has gained great attention as a promising drug target for preventing diabetic cardiovascular complications. And while animal studies have shown that several Nrf2 activators manifest a potential to efficiently prevent the diabetic complications, their use in humans has not been approved due to the lack of substantial evidence regarding safety and efficacy of the Nrf2 activation. We provide here a brief review of a few clinically-used drugs that can up-regulate Nrf2 with the potential of extending their usage to diabetic patients for the prevention of cardiovascular complications and conclude with a closer inspection of dimethyl fumarate and its mimic members. Copyright © 2015 Elsevier Inc. All rights reserved.

  8. Neuroligin-3 protects retinal cells from H2O2-induced cell death via activation of Nrf2 signaling.

    PubMed

    Li, Xiu-Miao; Huang, Dan; Yu, Qing; Yang, Jian; Yao, Jin

    2018-05-25

    Intensified oxidative stress can cause severe damage to human retinal pigment epithelium (RPE) cells and retinal ganglion cells (RGCs). The potential effect of neuroligin-3 (NLGN3) against the process is studied here. Our results show that NLGN3 efficiently inhibited hydrogen peroxide (H 2 O 2 )-induced death and apoptosis in human RPE cells and RGCs. H 2 O 2 -induced reactive oxygen species (ROS) production, lipid peroxidation and DNA damage in retinal cells were alleviated by NLGN3. NLGN3 activated nuclear-factor-E2-related factor 2 (Nrf2) signaling, enabling Nrf2 protein stabilization, nuclear translocation and expression of key anti-oxidant enzymes (HO1, NOQ1 and GCLC) in RPE cells and RGCs. Further results demonstrate that NLGN3 activated Akt-mTORC1 signaling in retinal cells. Conversely, Akt-mTORC1 inhibitors (RAD001 and LY294002) reduced NLGN3-induced HO1, NOQ1 and GCLC mRNA expression. Significantly, Nrf2 silencing by targeted shRNAs reversed NLGN3-induced retinal cytoprotection against H 2 O 2 . We conclude that NLGN3 activates Nrf2 signaling to protect human retinal cells from H 2 O 2 . NLGN3 could be further tested as a valuable retinal protection agent. Copyright © 2018 Elsevier Inc. All rights reserved.

  9. Nuclear Factor (Erythroid-Derived 2)-Like 2 and Thioredoxin-1 in Atherosclerosis and Ischemia/Reperfusion Injury in the Heart

    PubMed Central

    Jakobs, Philipp; Serbulea, Vlad; Leitinger, Norbert; Eckers, Anna

    2017-01-01

    Abstract Significance: Redox signaling is one of the key elements involved in cardiovascular diseases. Two important molecules are the transcription factor nuclear factor erythroid 2-related factor 2 (Nrf2) and the oxidoreductase thioredoxin-1 (Trx-1). Recent Advances: During the previous years, a lot of studies investigated Nrf2 and Trx-1 as protective proteins in cardiovascular disorders. Moreover, post-translational modifications of those molecules were identified that play an important role in the cardiovascular system. This review will summarize changes in the vasculature in atherosclerosis and ischemia reperfusion injury of the heart and the newest findings achieved with Nrf2 and Trx-1 therein. Interestingly, Nrf2 and Trx-1 can act together as well as independently of each other in protection against atherosclerosis and ischemia and reperfusion injury. Critical Issues: In principle, pharmacological activation of a transcription factor-like Nrf2 can be dangerous, since a transcription regulator has multiple targets and the pleiotropic effects of such activation should not be ignored. Moreover, overactivation of Nrf2 as well as long-term treatment with Trx-1 could be deleterious for the cardiovascular system. Future Directions: Therefore, the length of treatment with Nrf2 activators and/or Trx-1 has first to be studied in more detail in cardiovascular disorders. Moreover, a combination of Nrf2 activators and Trx-1 should be investigated and taken into consideration. Antioxid. Redox Signal. 26, 630–644. PMID:27923281

  10. Inhibition of early T cell cytokine production by arsenic trioxide occurs independently of Nrf2.

    PubMed

    VanDenBerg, Kelly R; Freeborn, Robert A; Liu, Sheng; Kennedy, Rebekah C; Zagorski, Joseph W; Rockwell, Cheryl E

    2017-01-01

    Nuclear factor erythroid 2-related factor 2 (Nrf2) is a stress-activated transcription factor that induces a variety of cytoprotective genes. Nrf2 also mediates immunosuppressive effects in multiple inflammatory models. Upon activation, Nrf2 dissociates from its repressor protein, Keap1, and translocates to the nucleus where it induces Nrf2 target genes. The Nrf2-Keap1 interaction is disrupted by the environmental toxicant and chemotherapeutic agent arsenic trioxide (ATO). The purpose of the present study was to determine the effects of ATO on early events of T cell activation and the role of Nrf2 in those effects. The Nrf2 target genes Hmox-1, Nqo-1, and Gclc were all upregulated by ATO (1-2 μM) in splenocytes derived from wild-type, but not Nrf2-null, mice, suggesting that Nrf2 is activated by ATO in splenocytes. ATO also inhibited IFNγ, IL-2, and GM-CSF mRNA and protein production in wild-type splenocytes activated with the T cell activator, anti-CD3/anti-CD28. However, ATO also decreased production of these cytokines in activated splenocytes from Nrf2-null mice, suggesting the inhibition is independent of Nrf2. Interestingly, ATO inhibited TNFα protein secretion, but not mRNA expression, in activated splenocytes suggesting the inhibition is due to post-transcriptional modification. In addition, c-Fos DNA binding was significantly diminished by ATO in wild-type and Nrf2-null splenocytes activated with anti-CD3/anti-CD28, consistent with the observed inhibition of cytokine production by ATO. Collectively, this study suggests that although ATO activates Nrf2 in splenocytes, inhibition of early T cell cytokine production by ATO occurs independently of Nrf2 and may instead be due to impaired AP-1 DNA binding.

  11. A novel role of the NRF2 transcription factor in the regulation of arsenite-mediated keratin 16 gene expression in human keratinocytes.

    PubMed

    Endo, Hitoshi; Sugioka, Yoshihiko; Nakagi, Yoshihiko; Saijo, Yasuaki; Yoshida, Takahiko

    2008-07-01

    Inorganic sodium arsenite (iAs) is a ubiquitous environmental contaminant and is associated with an increased risk of skin hyperkeratosis and cancer. We investigated the molecular mechanisms underlying the regulation of the keratin 16 (K16) gene by iAs in the human keratinocyte cell line HaCaT. We performed reverse transcriptase polymerase chain reaction, luciferase assays, Western blots, and electrophoretic mobility shift assays to determine the transcriptional regulation of the K16 gene by iAs. We used gene overexpression approaches to elucidate the nuclear factor erythroid-derived 2 related factor 2 (NRF2) involved in the K16 induction. iAs induced the mRNA and protein expression of K16. We also found that the expression of K16 was transcriptionally induced by iAs through activator protein-1-like sites and an antioxidant response element (ARE) in its gene promoter region. Treatment with iAs also enhanced the production and translocation of the NRF2 transcription factor, an ARE-binding protein, into the nucleus without modification of its mRNA expression. In addition, iAs elongated the half-life of the NRF2 protein. When overexpressed in HaCaT cells, NRF2 was also directly involved in not only the up-regulation of the detoxification gene thioredoxin but also K16 gene expression. Our data clearly indicate that the K16 gene is a novel target of NRF2. Furthermore, our findings also suggest that NRF2 has opposing roles in the cell--in the activation of detoxification pathways and in promoting the development of skin disorders.

  12. The nuclear factor-erythroid 2-related factor/heme oxygenase-1 axis is critical for the inflammatory features of type 2 diabetes-associated osteoarthritis.

    PubMed

    Vaamonde-Garcia, Carlos; Courties, Alice; Pigenet, Audrey; Laiguillon, Marie-Charlotte; Sautet, Alain; Houard, Xavier; Kerdine-Römer, Saadia; Meijide, Rosa; Berenbaum, Francis; Sellam, Jérémie

    2017-09-01

    Epidemiological findings support the hypothesis that type 2 diabetes mellitus (T2DM) is a risk factor for osteoarthritis (OA). Moreover, OA cartilage from patients with T2DM exhibits a greater response to inflammatory stress, but the molecular mechanism is unclear. To investigate whether the antioxidant defense system participates in this response, we examined here the expression of nuclear factor-erythroid 2-related factor (Nrf-2), a master antioxidant transcription factor, and of heme oxygenase-1 (HO-1), one of its main target genes, in OA cartilage from T2DM and non-T2DM patients as well as in murine chondrocytes exposed to high glucose (HG). Ex vivo experiments indicated that Nrf-2 and HO-1 expression is reduced in T2DM versus non-T2DM OA cartilage (0.57-fold Nrf-2 and 0.34-fold HO-1), and prostaglandin E 2 (PGE 2 ) release was increased in samples with low HO-1 expression. HG-exposed, IL-1β-stimulated chondrocytes had lower Nrf-2 levels in vitro , particularly in the nuclear fraction, than chondrocytes exposed to normal glucose (NG). Accordingly, HO-1 levels were also decreased (0.49-fold) in these cells. The HO-1 inducer cobalt protoporphyrin IX more efficiently attenuated PGE 2 and IL-6 release in HG+IL-1β-treated cells than in NG+IL-1β-treated cells. Greater reductions in HO-1 expression and increase in PGE 2 /IL-6 production were observed in HG+IL-1β-stimulated chondrocytes from Nrf-2 -/- mice than in chondrocytes from wild-type mice. We conclude that the Nrf-2/HO-1 axis is a critical pathway in the hyperglucidic-mediated dysregulation of chondrocytes. Impairments in this antioxidant system may explain the greater inflammatory responsiveness of OA cartilage from T2DM patients and may inform treatments of such patients. © 2017 by The American Society for Biochemistry and Molecular Biology, Inc.

  13. Systemic administration of the apocarotenoid bixin protects skin against solar UV-induced damage through activation of NRF2.

    PubMed

    Tao, Shasha; Park, Sophia L; Rojo de la Vega, Montserrat; Zhang, Donna D; Wondrak, Georg T

    2015-12-01

    Exposure to solar ultraviolet (UV) radiation is a causative factor in skin photodamage and carcinogenesis, and an urgent need exists for improved molecular photoprotective strategies different from (or synergistic with) photon absorption. Recent studies suggest a photoprotective role of cutaneous gene expression orchestrated by the transcription factor NRF2 (nuclear factor-E2-related factor 2). Here we have explored the molecular mechanism underlying carotenoid-based systemic skin photoprotection in SKH-1 mice and provide genetic evidence that photoprotection achieved by the FDA-approved apocarotenoid and food additive bixin depends on NRF2 activation. Bixin activates NRF2 through the critical Cys-151 sensor residue in KEAP1, orchestrating a broad cytoprotective response in cultured human keratinocytes as revealed by antioxidant gene expression array analysis. Following dose optimization studies for cutaneous NRF2 activation by systemic administration of bixin, feasibility of bixin-based suppression of acute cutaneous photodamage from solar UV exposure was investigated in Nrf2(+/+) versus Nrf2(-/-) SKH-1 mice. Systemic administration of bixin suppressed skin photodamage, attenuating epidermal oxidative DNA damage and inflammatory responses in Nrf2(+/+) but not in Nrf2(-/-) mice, confirming the NRF2-dependence of bixin-based cytoprotection. Taken together, these data demonstrate feasibility of achieving NRF2-dependent cutaneous photoprotection by systemic administration of the apocarotenoid bixin, a natural food additive consumed worldwide. Copyright © 2015 Elsevier Inc. All rights reserved.

  14. Nrf2 promotes neuronal cell differentiation.

    PubMed

    Zhao, Fei; Wu, Tongde; Lau, Alexandria; Jiang, Tao; Huang, Zheping; Wang, Xiao-Jun; Chen, Weimin; Wong, Pak Kin; Zhang, Donna D

    2009-09-15

    The transcription factor Nrf2 has emerged as a master regulator of the endogenous antioxidant response, which is critical in defending cells against environmental insults and in maintaining intracellular redox balance. However, whether Nrf2 has any role in neuronal cell differentiation is largely unknown. In this report, we have examined the effects of Nrf2 on cell differentiation using a neuroblastoma cell line, SH-SY5Y. Retinoic acid (RA) and 12-O-tetradecanoylphorbol 13-acetate, two well-studied inducers of neuronal differentiation, are able to induce Nrf2 and its target gene NAD(P)H quinone oxidoreductase 1 in a dose- and time-dependent manner. RA-induced Nrf2 up-regulation is accompanied by neurite outgrowth and an induction of two neuronal differentiation markers, neurofilament-M and microtubule-associated protein 2. Overexpression of Nrf2 in SH-SY5Y cells promotes neuronal differentiation, whereas inhibition of endogenous Nrf2 expression inhibited neuronal differentiation. More remarkably, the positive role of Nrf2 in neuronal differentiation was verified ex vivo in primary neuron culture. Primary neurons isolated from Nrf2-null mice showed a retarded progress in differentiation, compared to those from wild-type mice. Collectively, our data demonstrate a novel role for Nrf2 in promoting neuronal cell differentiation, which will open new perspectives for therapeutic uses of Nrf2 activators in patients with neurodegenerative diseases.

  15. Dibenzoylmethane Protects Against CCl4-Induced Acute Liver Injury by Activating Nrf2 via JNK, AMPK, and Calcium Signaling.

    PubMed

    Cao, Mingnan; Wang, Huixia; Guo, Limei; Yang, Simin; Liu, Chun; Khor, Tin Oo; Yu, Siwang; Kong, Ah-Ng

    2017-11-01

    Oxidative stress is an important pathogenic factor in various hepatic diseases. Nuclear factor-erythroid 2-related factor-2 (Nrf2), which coordinates the expression of an array of antioxidant and detoxifying genes, has been proposed as a potential target for prevention and treatment of liver disease. Dibenzoylmethane (DBM) is a minor ingredient in licorice that activates Nrf2 and prevents various cancers and oxidative damage. In the present study, the mechanisms by which DBM activates Nrf2 signaling were delineated, and its protective effect against carbon tetrachloride (CCl 4 )-induced liver injury was examined. DBM potently induced the expression of HO-1 in cells and in the livers of mice, but this induction was diminished in Nrf2-deficient mice and cells. Overexpression of Nrf2 enhanced DBM-induced HO-1 expression, while overexpression of a dominant-negative fragment of Nrf2 inhibited this induction. DBM treatment resulted in dissociation from Keap1 and nuclear translocation of Nrf2. Moreover, DBM activated Akt/protein kinase B, mitogen-activated protein kinases, and AMP-activated protein kinase and increased intracellular calcium levels. Inhibition of JNK, AMPK, or intracellular calcium signaling significantly suppressed the induction of HO-1 expression by DBM. Finally, DBM treatment significantly inhibited CCl 4 -induced acute liver injury in wild-type but not in Nrf2-deficient mice. Taken together, our results revealed the mechanisms by which DBM activates Nrf2 and induces HO-1 expression, and provide molecular basis for the design and development of DBM and its derivatives for prevention or treatment of liver diseases by targeting Nrf2.

  16. Minocycline attenuates sevoflurane-induced cell injury via activation of Nrf2

    PubMed Central

    Tian, Yue; Wu, Xiuying; Guo, Shanbin; Ma, Ling; Huang, Wei; Zhao, Xiaochun

    2017-01-01

    Minocycline has been demonstrated to exert neuroprotective effects in various experimental models. In the present study, we investigated the mechanisms underlying the protective effects of minocycline on cell injury induced by the inhalation of the anesthetic, sevoflurane. In our in vivo experiments using rats, minocycline attenuated sevoflurane-induced neuronal degeneration and apoptosis in the rat hippocampus, and this effect was associated with the minocycline-mediated suppression of oxidative stress in the hippocampus. In in vitro experiments, minocycline inhibited sevoflurane-induced apoptosis and the production of reactive oxygen species (ROS) in H4 human neuroglioma cells. In addition, minocycline suppressed the sevoflurane-induced upregulation of interleukin (IL)-6 and the activation of the nuclear factor-κB (NF-κB) signaling pathway in H4 cells. Furthermore, we found that nuclear factor E2-related factor 2 (Nrf2), an activator of the stress response, was upregulated and activated upon sevoflurane treatment both in the rat hippocampus and in H4 cells. In addition, minocycline further augmented the upregulation and activation of Nrf2 when used in conjunction with sevoflurane. Moreover, the knockdown of Nrf2 in H4 cells by small interfering RNA (siRNA) diminished the cytoprotective effect of minocycline, and attenuated the inhibitory effect of minocycline on ROS production, IL-6 upregulation and the activation of the NF-κB signaling pathway. On the whole, our findings indicate that minocycline may exert protective effects against sevoflurane-induced cell injury via the Nrf2-modulated antioxidant response and the inhibition of the activation of the NF-κB signaling pathway. PMID:28260081

  17. The regulatory role of Nrf2 in antioxidants phase2 enzymes and IL-17A expression in patients with ulcerative colitis.

    PubMed

    Sabzevary-Ghahfarokhi, Milad; Shohan, Mojtaba; Shirzad, Hedayatollah; Rahimian, Ghorbanali; Soltani, Amin; Ghatreh-Samani, Mahdi; Deris, Fatemeh; Bagheri, Nader; Shafigh, Mohammedhadi; Tahmasbi, Kamran

    2018-06-22

    Reactive oxygen species (ROS) is one of the pathogenic factors responsible for intestinal injury in Ulcerative colitis (UC). Nuclear factor erythroid-2 related factor 2 (Nrf2) plays a critical role against ROS factors to conserve epithelial integrity. This study aimed to localize Nrf2 and IL-17A protein in the inflamed mucosa of patients with ulcerative colitis. The gene expression of Nrf2 was also correlated with GST-A4 and PRDX1. A total of 20 patients and 20 healthy controls with definite UC based on the clinical criteria were enrolled for this study. The expression pattern of Nrf2 and IL-17A protein was compared in inflamed and non-inflamed colonic biopsies by immunohistochemical staining. Nrf2, GST-A4 and PRDX1 gene expression were determined by real-time polymerase chain reaction (RT-PCR). In inflamed colonic biopsies, an increased level of Nrf2 protein factor was detected in epithelial cells. Conversely, IL-17A protein was presented more in mononuclear cells in mucosa and lamina propria regions. A significant increase of Nrf2, GST-A4 gene expression was observed in both mild and severe patients with ulcerative colitis. GST-A4 gene expression indicated a high exponential rate in logistic regression. Oxidative stress in inflamed colonic tissue can induce Nrf2 gene expression. The performance of Nrf2 transcription factor may lead to the induction of GST-A4 and PRDX1. IL-17A is less detected in intestinal inflammation, presenting Nrf2 factor. The present findings suggest that Nrf2 function in the gut plays a role in arresting both inflammatory response and oxidative damages of UC. Copyright © 2018 Elsevier GmbH. All rights reserved.

  18. Anti-fibrotic effects of L-2-oxothiazolidine-4-carboxylic acid via modulation of nuclear factor erythroid 2-related factor 2 in rats.

    PubMed

    Kim, In Hee; Kim, Dae-Ghon; Hao, Peipei; Wang, Yunpeng; Kim, Seong Hun; Kim, Sang Wook; Lee, Seung Ok; Lee, Soo Teik

    2012-06-01

    L-2-Oxothiazolidine-4-carboxylic acid (OTC) is a cysteine prodrug that maintains glutathione in tissues. The present study was designed to investigate anti-fibrotic and anti-oxidative effects of OTC via modulation of nuclear factor erythroid 2-related factor 2 (Nrf2) in an in vivo thioacetamide (TAA)-induced hepatic fibrosis model. Treatment with OTC (80 or 160 mg/kg) improved serum liver function parameters and significantly ameliorated liver fibrosis. The OTC treatment groups exhibited significantly lower expression of α-smooth muscle actin, transforming growth factor-β 1, and collagen α 1 mRNA than that in the TAA model group. Furthermore, the OTC treatment groups showed a significant decrease in hepatic malondialdehyde level compared to that in the TAA model group. Nrf2 and heme oxygenase-1 expression increased significantly in the OTC treatment groups compared with that in the TAA model group. Taken together, these results suggest that OTC restores the anti- oxidative system by upregulating Nrf2; thus, ameliorating liver injury and a fibrotic reaction.

  19. Modulation of Nrf2 by Olive Oil and Wine Polyphenols and Neuroprotection

    PubMed Central

    Martínez-Huélamo, Miriam; Boronat, Anna; de la Torre, Rafael

    2017-01-01

    Strong adherence to a Mediterranean diet is associated with improved cognitive function and a lower prevalence of mild cognitive impairment. Olive oil and red wine are rich sources of polyphenols which are responsible in part for the beneficial effects on cognitive functioning. Polyphenols induce endogenous antioxidant defense mechanisms by modulating transcription factors such as the nuclear factor (erythroid-derived 2)-like 2 (Nrf2). This review discusses the scientific data supporting the modulating effect of olive oil and red wine polyphenols on Nrf2 expression, and the potential health benefits associated with cognitive functioning. PMID:28954417

  20. Targeting NRF2 for Improved Skin Barrier Function and Photoprotection: Focus on the Achiote-Derived Apocarotenoid Bixin

    PubMed Central

    Rojo de la Vega, Montserrat; Krajisnik, Andrea; Zhang, Donna D.; Wondrak, Georg T.

    2017-01-01

    The transcription factor NRF2 (nuclear factor-E2-related factor 2) orchestrates major cellular defense mechanisms including phase-II detoxification, inflammatory signaling, DNA repair, and antioxidant response. Recent studies strongly suggest a protective role of NRF2-mediated gene expression in the suppression of cutaneous photodamage induced by solar UV (ultraviolet) radiation. The apocarotenoid bixin, a Food and Drug Administration (FDA)-approved natural food colorant (referred to as ‘annatto’) originates from the seeds of the achiote tree native to tropical America, consumed by humans since ancient times. Use of achiote preparations for skin protection against environmental insult and for enhanced wound healing has long been documented. We have recently reported that (i) bixin is a potent canonical activator of the NRF2-dependent cytoprotective response in human skin keratinocytes; that (ii) systemic administration of bixin activates NRF2 with protective effects against solar UV-induced skin damage; and that (iii) bixin-induced suppression of photodamage is observable in Nrf2+/+ but not in Nrf2−/− SKH-1 mice confirming the NRF2-dependence of bixin-induced antioxidant and anti-inflammatory effects. In addition, bixin displays molecular activities as sacrificial antioxidant, excited state quencher, PPAR (peroxisome proliferator-activated receptor) α/γ agonist, and TLR (Toll-like receptor) 4/NFκB (nuclear factor kappa-light-chain-enhancer of activated B cells) antagonist, all of which might be relevant to the enhancement of skin barrier function and environmental stress protection. Potential skin photoprotection and photochemoprevention benefits provided by topical application or dietary consumption of this ethno-pharmacologically validated phytochemical originating from the Americas deserves further preclinical and clinical examination. PMID:29258247

  1. IDH1 R132H mutation regulates glioma chemosensitivity through Nrf2 pathway.

    PubMed

    Li, Kaishu; Ouyang, Leping; He, Mingliang; Luo, Ming; Cai, Wangqing; Tu, Yalin; Pi, Rongbiao; Liu, Anmin

    2017-04-25

    Numerous studies have reported that glioma patients with isocitrate dehydrogenase 1(IDH1) R132H mutation are sensitive to temozolomide treatment. However, the mechanism of IDH1 mutations on the chemosensitivity of glioma remains unclear. In this study, we investigated the role and the potential mechanism of Nrf2 in IDH1 R132H-mediated drug resistance. Wild type IDH1 (R132H-WT) and mutant IDH1 (R132H) plasmids were constructed. Stable U87 cells and U251 cells overexpressing IDH1 were generated. Phenotypic differences between IDH1-WT and IDH1 R132H overexpressing cells were evaluated using MTT, cell colony formation assay, scratch test assay and flow cytometry. Expression of IDH1 and its associated targets, nuclear factor-erythroid 2-related factor 2 (Nrf2), NAD(P)H quinine oxidoreductase 1 (NQO1), multidrug resistant protein 1 (MRP1) and p53 were analyzed. The IDH1 R132H overexpressing cells were more sensitive to temozolomide than WT and the control, and Nrf2 was significantly decreased in IDH1 R132H overexpressing cells. We found that knocking down Nrf2 could decrease resistance to temozolomide. The nuclear translocation of Nrf2 in IDH1 R132H overexpressing cells was lower than the WT and the control groups after temozolomide treatment. When compared with WT cells, NQO1 expression was reduced in IDH1 R132H cells, especially after temozolomide treatment. P53 was involved in the resistance mechanism of temozolomide mediated by Nrf2 and NQO1. Nrf2 played an important role in IDH1 R132H-mediated drug resistance. The present study provides new insight for glioma chemotherapy with temozolomide.

  2. IDH1 R132H mutation regulates glioma chemosensitivity through Nrf2 pathway

    PubMed Central

    Luo, Ming; Cai, Wangqing; Tu, Yalin; Pi, Rongbiao; Liu, Anmin

    2017-01-01

    Purpose Numerous studies have reported that glioma patients with isocitrate dehydrogenase 1(IDH1) R132H mutation are sensitive to temozolomide treatment. However, the mechanism of IDH1 mutations on the chemosensitivity of glioma remains unclear. In this study, we investigated the role and the potential mechanism of Nrf2 in IDH1 R132H-mediated drug resistance. Methods Wild type IDH1 (R132H-WT) and mutant IDH1 (R132H) plasmids were constructed. Stable U87 cells and U251 cells overexpressing IDH1 were generated. Phenotypic differences between IDH1-WT and IDH1 R132H overexpressing cells were evaluated using MTT, cell colony formation assay, scratch test assay and flow cytometry. Expression of IDH1 and its associated targets, nuclear factor-erythroid 2-related factor 2 (Nrf2), NAD(P)H quinine oxidoreductase 1 (NQO1), multidrug resistant protein 1 (MRP1) and p53 were analyzed. Results The IDH1 R132H overexpressing cells were more sensitive to temozolomide than WT and the control, and Nrf2 was significantly decreased in IDH1 R132H overexpressing cells. We found that knocking down Nrf2 could decrease resistance to temozolomide. The nuclear translocation of Nrf2 in IDH1 R132H overexpressing cells was lower than the WT and the control groups after temozolomide treatment. When compared with WT cells, NQO1 expression was reduced in IDH1 R132H cells, especially after temozolomide treatment. P53 was involved in the resistance mechanism of temozolomide mediated by Nrf2 and NQO1. Conclusions Nrf2 played an important role in IDH1 R132H-mediated drug resistance. The present study provides new insight for glioma chemotherapy with temozolomide. PMID:28427200

  3. Ischemic Preconditioning Protects Astrocytes against Oxygen Glucose Deprivation Via the Nuclear Erythroid 2-Related Factor 2 Pathway.

    PubMed

    Narayanan, Srinivasan V; Dave, Kunjan R; Perez-Pinzon, Miguel A

    2018-04-01

    Induction of ischemic preconditioning (IPC) represents a potential therapy against cerebral ischemia by activation of adaptive pathways and modulation of mitochondria to induce ischemic tolerance to various cells and tissues. Mitochondrial dysfunction has been ascribed to contribute to numerous neurodegenerative conditions and cerebral ischemia. Nuclear erythroid 2-related factor 2 (Nrf2) is a transcription factor that has traditionally been involved in upregulating cellular antioxidant systems to combat oxidative stress in the brain; however, the association of Nrf2 with mitochondria in the brain remains unclear. In the present study, we investigated the effects of Nrf2 on (i) IPC-induced protection of astrocytes; (ii) OXPHOS protein expression; and (iii) mitochondrial supercomplex formation.Oxygen-glucose deprivation (OGD) was used as an in vitro model of cerebral ischemia and IPC in cultured rodent astrocytes derived from WT C57Bl/6J and Nrf2 -/- mice. OXPHOS proteins were probed via western blotting, and supercomplexes were determined by blue native gel electrophoresis.IPC-induced cytoprotection in wild-type, but not Nrf2 -/- mouse astrocyte cultures following a lethal duration of OGD. In addition, our results suggest that Nrf2 localizes to the outer membrane in non-synaptic brain mitochondria, and that a lack of Nrf2 in vivo produces altered supercomplex formation in mitochondria.Our findings support a role of Nrf2 in mediating IPC-induced protection in astrocytes, which can profoundly impact the ischemic tolerance of neurons. In addition, we provide novel evidence for the association of Nrf2 to brain mitochondria and supercomplex formation. These studies offer new targets and pathways of Nrf2, which may be heavily implicated following cerebral ischemia.

  4. Nrf2 deficiency potentiates methamphetamine-induced dopaminergic axonal damage and gliosis in the striatum.

    PubMed

    Granado, Noelia; Lastres-Becker, Isabel; Ares-Santos, Sara; Oliva, Idaira; Martin, Eduardo; Cuadrado, Antonio; Moratalla, Rosario

    2011-12-01

    Oxidative stress that correlates with damage to nigrostriatal dopaminergic neurons and reactive gliosis in the basal ganglia is a hallmark of methamphetamine (METH) toxicity. In this study, we analyzed the protective role of the transcription factor Nrf2 (nuclear factor-erythroid 2-related factor 2), a master regulator of redox homeostasis, in METH-induced neurotoxicity. We found that Nrf2 deficiency exacerbated METH-induced damage to dopamine neurons, shown by an increase in loss of tyrosine hydroxylase (TH)- and dopamine transporter (DAT)-containing fibers in striatum. Consistent with these effects, Nrf2 deficiency potentiated glial activation, indicated by increased striatal expression of markers for microglia (Mac-1 and Iba-1) and astroglia (GFAP) one day after METH administration. At the same time, Nrf2 inactivation dramatically potentiated the increase in TNFα mRNA and IL-15 protein expression in GFAP+ cells in the striatum. In sharp contrast to the potentiation of striatal damage, Nrf2 deficiency did not affect METH-induced dopaminergic neuron death or expression of glial markers or proinflammatory molecules in the substantia nigra. This study uncovers a new role for Nrf2 in protection against METH-induced inflammatory and oxidative stress and striatal degeneration. Copyright © 2011 Wiley‐Liss, Inc.

  5. Clinically significant association of elevated expression of nuclear factor E2-related factor 2 expression with higher glucose uptake and progression of upper urinary tract cancer.

    PubMed

    Nukui, Akinori; Narimatsu, Takahiro; Kambara, Tsunehito; Abe, Hideyuki; Sakamoto, Setsu; Yoshida, Ken-Ichiro; Kamai, Takao

    2018-05-02

    There is growing evidence that the transcription factor nuclear factor E2-related factor 2 (Nrf2) is the major participant in regulating antioxidants and pathways for detoxifying reactive oxygen species (ROS), as well as having a vital role in tumor proliferation, invasion, and chemoresistance. It was also recently reported that Nrf2 supports cell proliferation by promoting metabolic activity. Thus, Nrf2 is involved in progression of cancer. Upper urinary tract urothelial carcinoma (UTUC) is a biologically aggressive tumor with high rates of recurrence and progression, resulting in a poor prognosis. However, the role of Nrf2 in UTUC is largely unknown. In order to study the role of Nrf2 in UTUC from the metabolic perspective, we retrospectively assessed Nrf2 expression in the surgical specimen and the preoperative maximum standard glucose uptake (SUVmax) on [ 18 F]fluorodeoxy-glucose positron emission tomography ( 18 F-FDG-PET) of 107 patients with UTUC who underwent radical nephroureterectomy. Increased expression of Nrf2 in the primary lesion was correlated with less differentiated histology, local invasion, and lymph node metastasis, and was also an independent indicator of shorter overall survival according to multivariate analysis. Furthermore, increased expression of Nrf2 was associated with higher preoperative SUVmax by the primary tumor on 18 F-FDG-PET, while Nrf2 expression and SUVmax were also significantly correlated in the metastatic lymph nodes. Among the 18 patients with lymph node metastasis at nephroureterectomy who underwent retroperitoneal lymph node dissection and received adjuvant chemotherapy, the patients with higher Nrf2 expression in the primary tumor had worse recurrence-free survival. These results suggest that constitutive activation of Nrf2 might be linked with tumor aerobic glycolysis and progression of UTUC, indicating that Nrf2 signaling in the tumor microenvironment promotes progression of UTUC.

  6. Nrf2 Activation Induced by Sirt1 Ameliorates Acute Lung Injury After Intestinal Ischemia/Reperfusion Through NOX4-Mediated Gene Regulation.

    PubMed

    Chai, DongDong; Zhang, Lei; Xi, SiWei; Cheng, YanYong; Jiang, Hong; Hu, Rong

    2018-01-01

    Nuclear erythroid 2-related factor-2 (Nrf2) is a major stress-response transcription factor that has been implicated in regulating ischemic angiogenesis. We investigated the effects of Nrf2 in regulating revascularization and modulating acute lung injury. The expression of Nrf2 and sirtuin1 (Sirt1) was assessed in lung tissue by western blotting and immunofluorescence staining after intestinal ischemia/reperfusion (IIR) in Nrf2-/- and wild-type (WT) mice. The involvement of Nrf2 in angiogenesis, cell viability, and migration was investigated in human pulmonary microvascular endothelial cells (PMVECs). Additionally, the influence of Nrf2 expression on NOX pathway activation was measured in PMVECs after oxygen-glucose deprivation/reoxygenation. We found activation and nuclear accumulation of Nrf2 in lung tissue after IIR. Compared to IIR in WT mice, IIR in Nrf2-/- mice significantly enhanced leukocyte infiltration and collagen deposit, and inhibited endothelial cell marker CD31 expression. Nrf2 upregulation and translocation into the nucleus stimulated by Sirt1 overexpression exhibited remission of histopathologic changes and enhanced CD31 expression. Nrf2 knockdown repressed non-phagocytic cell oxidase 4 (NOX4), hypoxia-inducible factor (HIF-1α) and vascular endothelial growth factor (VEGF) expression after IIR. Nrf2 upregulation by Sirt1 enhances NOX4, HIF-1α and VEGF expression after IIR in WT mice. Furthermore, Nrf2 knockdown suppressed cell viability, capillary tube formation and cell migration in PMVECs after oxygen-glucose deprivation/reoxygenation and also inhibited NOX4, HIF-1 and VEGF expression. Moreover, NOX4 knockdown in PMVECs decreased the levels of VEGF, HIF-1α and angiogenesis. Nrf2 stimulation by Sirt1 plays an important role in sustaining angiogenic potential through NOX4-mediated gene regulation. © 2018 The Author(s). Published by S. Karger AG, Basel.

  7. An overview of the molecular mechanisms and novel roles of Nrf2 in neurodegenerative disorders.

    PubMed

    Yang, Yang; Jiang, Shuai; Yan, Juanjuan; Li, Yue; Xin, Zhenlong; Lin, Yan; Qu, Yan

    2015-02-01

    Recently, growing evidence has demonstrated that nuclear factor erythroid 2-related factor 2 (Nrf2) is a pivotal regulator of endogenous defense systems that function via the activation of a set of protective genes, and this is particularly clear in the central nervous system (CNS). Therefore, it is highly useful to summarize the current literature on the molecular mechanisms and role of Nrf2 in the CNS. In this review, we first briefly introduce the molecular features of Nrf2. We then discuss the regulation, cerebral actions, upstream modulators and downstream targets of Nrf2 pathway. Following this background, we expand our discussion to the role of Nrf2 in several major neurodegenerative disorders (NDDs) such as Alzheimer's disease, Parkinson's disease, Huntington's disease, multiple sclerosis and amyotrophic lateral sclerosis. Lastly, we discuss some potential future directions. The information reviewed here may be significant in the design of further experimental research and increase the potential of Nrf2 as a therapeutic target in the future. Copyright © 2014 Elsevier Ltd. All rights reserved.

  8. Global mapping of binding sites for Nrf2 identifies novel targets in cell survival response through ChIP-Seq profiling and network analysis

    PubMed Central

    Malhotra, Deepti; Portales-Casamar, Elodie; Singh, Anju; Srivastava, Siddhartha; Arenillas, David; Happel, Christine; Shyr, Casper; Wakabayashi, Nobunao; Kensler, Thomas W.; Wasserman, Wyeth W.; Biswal, Shyam

    2010-01-01

    The Nrf2 (nuclear factor E2 p45-related factor 2) transcription factor responds to diverse oxidative and electrophilic environmental stresses by circumventing repression by Keap1, translocating to the nucleus, and activating cytoprotective genes. Nrf2 responses provide protection against chemical carcinogenesis, chronic inflammation, neurodegeneration, emphysema, asthma and sepsis in murine models. Nrf2 regulates the expression of a plethora of genes that detoxify oxidants and electrophiles and repair or remove damaged macromolecules, such as through proteasomal processing. However, many direct targets of Nrf2 remain undefined. Here, mouse embryonic fibroblasts (MEF) with either constitutive nuclear accumulation (Keap1−/−) or depletion (Nrf2−/−) of Nrf2 were utilized to perform chromatin-immunoprecipitation with parallel sequencing (ChIP-Seq) and global transcription profiling. This unique Nrf2 ChIP-Seq dataset is highly enriched for Nrf2-binding motifs. Integrating ChIP-Seq and microarray analyses, we identified 645 basal and 654 inducible direct targets of Nrf2, with 244 genes at the intersection. Modulated pathways in stress response and cell proliferation distinguish the inducible and basal programs. Results were confirmed in an in vivo stress model of cigarette smoke-exposed mice. This study reveals global circuitry of the Nrf2 stress response emphasizing Nrf2 as a central node in cell survival response. PMID:20460467

  9. Activation of Nrf2 contributes to the protective effect of Exendin-4 against angiotensin II-induced vascular smooth muscle cell senescence.

    PubMed

    Zhou, Tengfei; Zhang, Mengqian; Zhao, Liang; Li, Aiqin; Qin, Xiaomei

    2016-10-01

    Oxidative stress and impaired antioxidant defense are believed to be contributors to the cardiovascular aging process. The transcription factor nuclear factor-E2-related factor 2 (Nrf2) plays a key role in orchestrating cellular antioxidant defenses and maintaining redox homeostasis. Our previous study showed that Exendin-4, a glucagon-like peptide-1 analog, alleviates angiotensin II (ANG II)-induced vascular smooth muscle cell (VSMC) senescence by inhibiting Rac1 activation via cAMP/PKA (Zhao L, Li AQ, Zhou TF, Zhang MQ, Qin XM. Am J Physiol Cell Physiol 307: C1130-C1141, 2014). The objective of this study is to investigate if Nrf2 mediates the antisenescent effect of Exendin-4 in ANG II-induced VSMCs. Here we report that Exendin-4 triggered Nrf2 nuclear translocation, a downstream target of cAMP-responsive element-binding protein (CREB) and expressions of antioxidant genes heme oxygenase-1 (HO-1) and NAD(P)H quinone oxidoreductase-1 (NQO-1) in a dose- and time-dependent manner. In addition, knock-down of Nrf2 attenuated the inhibitory effects of Exendin-4 on ANG II-induced superoxidant generation and VSMC senescence. PKA/CREB pathway participated in the upregulations of HO-1 and NQO-1 induced by Exendin-4. Notably, our study revealed that Exendin-4 dose-dependently increased the acetylation of Nrf2 and the recruitment of transcriptional coactivator CREB binding protein (CBP) to Nrf2. The Exendin-4-induced Nrf2 transactivation was diminished in the presence of CBP small interfering RNA. Microscope imaging of Nrf2, as well as immunoblotting for Nrf2, showed that the Exendin-4-evoked Nrf2 acetylation favored its nuclear retention. Importantly, CBP silencing attenuated the suppressing effects of Exendin-4 on ANG II-induced VSMC senescence and superoxidant production. In conclusion, these results provide a mechanistic insight into how Nrf2 signaling mediates the antisenescent and antioxidative effects induced by Exendin-4 in VSMCs. Copyright © 2016 the American

  10. Suppression of nuclear factor erythroid‑2‑related factor 2‑mediated antioxidative defense in the lung injury induced by chronic exposure to methamphetamine in rats.

    PubMed

    Bai, Yang; Wang, Yun; Liu, Ming; Gu, Yu-Han; Jiang, Bin; Wu, Xu; Wang, Huai-Liang

    2017-05-01

    The imbalance between oxidative stress and antioxidant defense is important in the pathogenesis of lung diseases. Nuclear factor erythroid‑2‑related factor 2 (Nrf2) is a key transcriptional factor that regulates the antioxidant response. The purpose of the present study was to investigate whether Nrf2‑mediated antioxidative defense is involved in methamphetamine (MA)‑induced lung injury in rats. Following establishment of chronic MA toxicity in rats, Doppler ultrasonic detection was used to measure the changes of physiological indexes, followed by hematoxylin and eosin staining, ELISA and western blot analysis. MA was demonstrated to increase the heart rate and peak blood flow velocity of pulmonary arterial valves and to decrease the survival rate of rats, and resulted in lung injury characterized by perivascular exudates, airspace edema, slight hemorrhage and inflammatory cell infiltration. MA significantly inhibited the expression of nuclear Nrf2 protein and its target genes (glutamate‑cysteine ligase catalytic subunit C and heme oxygenase‑1), and dose‑dependently reduced glutathione (GSH) levels and the ratio of GSH/oxidized glutathione, accompanied by increases in reactive oxygen species (ROS) levels in rat lungs. Linear regression analysis revealed that there was a positive correlation between lung ROS level and lung injury indexes. These findings suggested that chronic exposure to MA led to lung injury by suppression of Nrf2‑mediated antioxidative defense, suggesting that Nrf2 may be an important therapeutic target for MA‑induced chronic lung toxicity.

  11. The Antioxidant Transcription Factor Nrf2 Negatively Regulates Autophagy and Growth Arrest Induced by the Anticancer Redox Agent Mitoquinone*

    PubMed Central

    Rao, V. Ashutosh; Klein, Sarah R.; Bonar, Spencer J.; Zielonka, Jacek; Mizuno, Naoko; Dickey, Jennifer S.; Keller, Paul W.; Joseph, Joy; Kalyanaraman, Balaraman; Shacter, Emily

    2010-01-01

    Mitoquinone (MitoQ) is a synthetically modified, redox-active ubiquinone compound that accumulates predominantly in mitochondria. We found that MitoQ is 30-fold more cytotoxic to breast cancer cells than to healthy mammary cells. MitoQ treatment led to irreversible inhibition of clonogenic growth of breast cancer cells through a combination of autophagy and apoptotic cell death mechanisms. Relatively limited cytotoxicity was seen with the parent ubiquinone coenzyme Q10. Inhibition of cancer cell growth by MitoQ was associated with G1/S cell cycle arrest and phosphorylation of the checkpoint kinases Chk1 and Chk2. The possible role of oxidative stress in MitoQ activity was investigated by measuring the products of hydroethidine oxidation. Increases in ethidium and dihydroethidium levels, markers of one-electron oxidation of hydroethidine, were observed at cytotoxic concentrations of MitoQ. Keap1, an oxidative stress sensor protein that regulates the antioxidant transcription factor Nrf2, underwent oxidation, degradation, and dissociation from Nrf2 in MitoQ-treated cells. Nrf2 protein levels, nuclear localization, and transcriptional activity also increased following MitoQ treatment. Knockdown of Nrf2 caused a 2-fold increase in autophagy and an increase in G1 cell cycle arrest in response to MitoQ but had no apparent effect on apoptosis. The Nrf2-regulated enzyme NQO1 is partly responsible for controlling the level of autophagy. Keap1 and Nrf2 act as redox sensors for oxidative perturbations that lead to autophagy. MitoQ and similar compounds should be further evaluated for novel anticancer activity. PMID:20805228

  12. The antioxidant transcription factor Nrf2 negatively regulates autophagy and growth arrest induced by the anticancer redox agent mitoquinone.

    PubMed

    Rao, V Ashutosh; Klein, Sarah R; Bonar, Spencer J; Zielonka, Jacek; Mizuno, Naoko; Dickey, Jennifer S; Keller, Paul W; Joseph, Joy; Kalyanaraman, Balaraman; Shacter, Emily

    2010-11-05

    Mitoquinone (MitoQ) is a synthetically modified, redox-active ubiquinone compound that accumulates predominantly in mitochondria. We found that MitoQ is 30-fold more cytotoxic to breast cancer cells than to healthy mammary cells. MitoQ treatment led to irreversible inhibition of clonogenic growth of breast cancer cells through a combination of autophagy and apoptotic cell death mechanisms. Relatively limited cytotoxicity was seen with the parent ubiquinone coenzyme Q(10.) Inhibition of cancer cell growth by MitoQ was associated with G(1)/S cell cycle arrest and phosphorylation of the checkpoint kinases Chk1 and Chk2. The possible role of oxidative stress in MitoQ activity was investigated by measuring the products of hydroethidine oxidation. Increases in ethidium and dihydroethidium levels, markers of one-electron oxidation of hydroethidine, were observed at cytotoxic concentrations of MitoQ. Keap1, an oxidative stress sensor protein that regulates the antioxidant transcription factor Nrf2, underwent oxidation, degradation, and dissociation from Nrf2 in MitoQ-treated cells. Nrf2 protein levels, nuclear localization, and transcriptional activity also increased following MitoQ treatment. Knockdown of Nrf2 caused a 2-fold increase in autophagy and an increase in G(1) cell cycle arrest in response to MitoQ but had no apparent effect on apoptosis. The Nrf2-regulated enzyme NQO1 is partly responsible for controlling the level of autophagy. Keap1 and Nrf2 act as redox sensors for oxidative perturbations that lead to autophagy. MitoQ and similar compounds should be further evaluated for novel anticancer activity.

  13. Effects of Nuclear Factor-E2-related factor 2/Heme Oxygenase 1 on splanchnic hemodynamics in experimental cirrhosis with portal hypertension.

    PubMed

    Qin, Jun; He, Yue; Duan, Ming; Luo, Meng

    2017-05-01

    We explored the effects of Nuclear Factor-E2-related factor 2 (Nrf2) and Heme Oxygenase 1 (HO-1) on splanchnic hemodynamics in portal hypertensive rats. Experimental cirrhosis with portal hypertension was induced by intraperitoneal injection of carbon tetrachloride. The expression of proteins was examined by immunoblotting. Hemodynamic studies were performed by radioactive microspheres. The vascular perfusion system was used to measure the contractile response of mesentery arterioles in rats. Nrf2 expression in the nucleus and HO-1 expression in cytoplasm was significantly enhanced in portal hypertensive rats. Portal pressure, as well as regional blood flow, increased significantly in portal hypertension and can be blocked by tin protoporphyrin IX. The expression of endogenous nitric oxide synthase and vascular endothelial growth factors increased significantly compared to normal rats, while HO-1 inhibition decreased the expression of these proteins significantly. The contractile response of mesenteric arteries decreased in portal hypertension, but can be partially recovered through tin protoporphyrin IX treatment. The expression of Nrf2/HO-1 increased in mesenteric arteries of portal hypertensive rats, which was related to oxidative stress. HO-1was involved in increased portal pressure and anomaly splanchnic hemodynamics in portal hypertensive rats. Copyright © 2016 Elsevier Inc. All rights reserved.

  14. Gestational diabetes mellitus impairs Nrf2-mediated adaptive antioxidant defenses and redox signaling in fetal endothelial cells in utero.

    PubMed

    Cheng, Xinghua; Chapple, Sarah J; Patel, Bijal; Puszyk, William; Sugden, David; Yin, Xiaoke; Mayr, Manuel; Siow, Richard C M; Mann, Giovanni E

    2013-12-01

    In utero exposure to gestational diabetes mellitus (GDM) is associated with an increased risk of type 2 diabetes and cardiovascular disease in later life, yet the underlying mechanisms remain to be elucidated. We examined the effects of GDM on the proteome, redox status, and nuclear factor erythroid 2-related factor 2 (Nrf2)-mediated antioxidant gene expression in human fetal endothelial cells. Proteomic analysis revealed that proteins involved in redox homeostasis were significantly altered in GDM and associated with increased mitochondrial superoxide generation, protein oxidation, DNA damage, and diminished glutathione (GSH) synthesis. In GDM cells, the lipid peroxidation product 4-hydroxynonenal (HNE) failed to induce nuclear Nrf2 accumulation and mRNA and/or protein expression of Nrf2 and its target genes NAD(P)H:quinone oxidoreductase 1 (NQO1), Bach1, cystine/glutamate transporter, and glutamate cysteine ligase. Although methylation of CpG islands in Nrf2 or NQO1 promoters was unaltered by GDM, decreased DJ-1 and increased phosphorylated glycogen synthase kinase 3β levels may account for impaired Nrf2 signaling. HNE-induced increases in GSH and NQO1 levels were abrogated by Nrf2 small interfering RNA in normal cells, and overexpression of Nrf2 in GDM cells partially restored NQO1 induction. Dysregulation of Nrf2 in fetal endothelium may contribute to the increased risk of type 2 diabetes and cardiovascular disease in offspring.

  15. Dihydro-CDDO-trifluoroethyl amide suppresses inflammatory responses in macrophages via activation of Nrf2

    DOE Office of Scientific and Technical Information (OSTI.GOV)

    Li, Bin; Department of Cell Biology and Anatomy, University of South Carolina School of Medicine, Columbia, SC 29208; Abdalrahman, Akram

    2014-02-21

    Highlights: • Dh404 suppresses the expression of a selected set of pro-inflammatory cytokines in inflamed macrophages via activating Nrf2. • Dh404 activates Nrf2 while keeping Keap1 function intact in macrophages. • Dh404 minimally regulates NF-κB pathway in macrophages. - Abstract: Nuclear factor erythroid 2-related factor (Nrf2) is the major regulator of cellular defenses against various pathological stresses in a variety of organ systems, thus Nrf2 has evolved to be an attractive drug target for the treatment and/or prevention of human disease. Several synthetic oleanolic triterpenoids including dihydro-CDDO-trifluoroethyl amide (dh404) appear to be potent activators of Nrf2 and exhibit chemopreventive promisesmore » in multiple disease models. While the pharmacological efficacy of Nrf2 activators may be dependent on the nature of Nrf2 activation in specific cell types of target organs, the precise role of Nrf2 in mediating biological effects of Nrf2 activating compounds in various cell types remains to be further explored. Herein we report a unique and Nrf2-dependent anti-inflammatory profile of dh404 in inflamed macrophages. In lipopolysaccharide (LPS)-inflamed RAW264.7 macrophages, dh404 dramatically suppressed the expression of pro-inflammatory cytokines including inducible nitric oxide synthase (iNOS), monocyte chemotactic protein-1 (MCP-1), and macrophage inflammatory protein-1 beta (MIP-1β), while minimally regulating the expression of interleulin-6 (IL-6), IL-1β, and tumor necrosis factor alpha (TNFα). Dh404 potently activated Nrf2 signaling; however, it did not affect LPS-induced NF-κB activity. Dh404 did not interrupt the interaction of Nrf2 with its endogenous inhibitor Kelch-like ECH associating protein 1 (Keap1) in macrophages. Moreover, knockout of Nrf2 blocked the dh404-induced anti-inflammatory responses in LPS-inflamed macrophages. These results demonstrated that dh404 suppresses pro-inflammatory responses in macrophages via an

  16. Differential expression of the Nrf2-linked genes in pediatric septic shock.

    PubMed

    Grunwell, Jocelyn R; Weiss, Scott L; Cvijanovich, Natalie Z; Allen, Geoffrey L; Thomas, Neal J; Freishtat, Robert J; Anas, Nick; Meyer, Keith; Checchia, Paul A; Shanley, Thomas P; Bigham, Michael T; Fitzgerald, Julie; Howard, Kelli; Frank, Erin; Harmon, Kelli; Wong, Hector R

    2015-09-17

    Experimental data from animal models of sepsis support a role for a transcription factor, nuclear erythroid-related factor 2 p45-related factor 2 (Nrf2), as a master regulator of antioxidant and detoxifying genes and intermediary metabolism during stress. Prior analysis of a pediatric septic shock transcriptomic database showed that the Nrf2 response is a top 5 upregulated signaling pathway in early pediatric septic shock. We conducted a focused analysis of 267 Nrf2-linked genes using a multicenter, genome-wide expression database of 180 children with septic shock 10 years of age or younger and 53 healthy controls. The analysis involved RNA isolated from whole blood within 24 h of pediatric intensive care unit admission for septic shock and a false discovery rate of 5 %. We compared differentially expressed genes from (1) patients with septic shock and healthy controls and (2) across validated gene expression-based subclasses of pediatric septic shock (endotypes A and B) using several bioinformatic methods. We found upregulation of 123 Nrf2-linked genes in children with septic shock. The top gene network represented by these genes contained primarily enzymes with oxidoreductase activity involved in cellular lipid metabolism that were highly connected to the peroxisome proliferator activated receptor and the retinoic acid receptor families. Endotype A, which had higher organ failure burden and mortality, exhibited a greater downregulation of Nrf2-linked genes than endotype B, with 92 genes differentially regulated between endotypes. Our findings indicate that Nrf2-linked genes may contribute to alterations in oxidative signaling and intermediary metabolism in pediatric septic shock.

  17. The Role of the Nrf2/ARE Antioxidant System in Preventing Cardiovascular Diseases

    PubMed Central

    Smith, Robert E.; Tran, Kevin; Smith, Cynthia C.; McDonald, Miranda; Shejwalkar, Pushkar; Hara, Kenji

    2016-01-01

    It is widely believed that consuming foods and beverages that have high concentrations of antioxidants can prevent cardiovascular diseases and many types of cancer. As a result, many articles have been published that give the total antioxidant capacities of foods in vitro. However, many antioxidants behave quite differently in vivo. Some of them, such as resveratrol (in red wine) and epigallocatechin gallate or EGCG (in green tea) can activate the nuclear erythroid-2 like factor-2 (Nrf2) transcription factor. It is a master regulator of endogenous cellular defense mechanisms. Nrf2 controls the expression of many antioxidant and detoxification genes, by binding to antioxidant response elements (AREs) that are commonly found in the promoter region of antioxidant (and other) genes, and that control expression of those genes. The mechanisms by which Nrf2 relieves oxidative stress and limits cardiac injury as well as the progression to heart failure are described. Also, the ability of statins to induce Nrf2 in the heart, brain, lung, and liver is mentioned. However, there is a negative side of Nrf2. When over-activated, it can cause (not prevent) cardiovascular diseases and multi-drug resistance cancer. PMID:28933413

  18. Nrf2 reduces levels of phosphorylated tau protein by inducing autophagy adaptor protein NDP52

    NASA Astrophysics Data System (ADS)

    Jo, Chulman; Gundemir, Soner; Pritchard, Susanne; Jin, Youngnam N.; Rahman, Irfan; Johnson, Gail V. W.

    2014-03-01

    Nuclear factor erythroid 2-related factor 2 (Nrf2) is a pivotal transcription factor in the defence against oxidative stress. Here we provide evidence that activation of the Nrf2 pathway reduces the levels of phosphorylated tau by induction of an autophagy adaptor protein NDP52 (also known as CALCOCO2) in neurons. The expression of NDP52, which we show has three antioxidant response elements (AREs) in its promoter region, is strongly induced by Nrf2, and its overexpression facilitates clearance of phosphorylated tau in the presence of an autophagy stimulator. In Nrf2-knockout mice, phosphorylated and sarkosyl-insoluble tau accumulates in the brains concurrent with decreased levels of NDP52. Moreover, NDP52 associates with phosphorylated tau from brain cortical samples of Alzheimer disease cases, and the amount of phosphorylated tau in sarkosyl-insoluble fractions is inversely proportional to that of NDP52. These results suggest that NDP52 plays a key role in autophagy-mediated degradation of phosphorylated tau in vivo.

  19. The Nrf2-antioxidant response element pathway: a target for regulating energy metabolism

    USDA-ARS?s Scientific Manuscript database

    The nuclear factor E2-related factor 2 (Nrf2) is a transcription factor that responds to oxidative stress by binding to the antioxidant response element (ARE) in the promoter of genes coding for antioxidant enzymes like NAD(P)H:quinone oxidoreductase 1 (NQO1) and proteins for glutathione synthesis. ...

  20. Protective effect of nuclear factor E2-related factor 2 on inflammatory cytokine response to brominated diphenyl ether-47 in the HTR-8/SVneo human first trimester extravillous trophoblast cell line.

    PubMed

    Park, Hae-Ryung; Loch-Caruso, Rita

    2014-11-15

    Polybrominated diphenyl ethers (PBDEs) are widely used flame retardants, and BDE-47 is a prevalent PBDE congener detected in human tissues. Exposure to PBDEs has been linked to adverse pregnancy outcomes in humans. Although the underlying mechanisms of adverse birth outcomes are poorly understood, critical roles for oxidative stress and inflammation are implicated. The present study investigated antioxidant responses in a human extravillous trophoblast cell line, HTR-8/SVneo, and examined the role of nuclear factor E2-related factor 2 (Nrf2), an antioxidative transcription factor, in BDE-47-induced inflammatory responses in the cells. Treatment of HTR-8/SVneo cells with 5, 10, 15, and 20μM BDE-47 for 24h increased intracellular glutathione (GSH) levels compared to solvent control. Treatment of HTR-8/SVneo cells with 20μM BDE-47 for 24h induced the antioxidant response element (ARE) activity, indicating Nrf2 transactivation by BDE-47 treatment, and resulted in differential expression of redox-sensitive genes compared to solvent control. Pretreatment with tert-butyl hydroquinone (tBHQ) or sulforaphane, known Nrf2 inducers, reduced BDE-47-stimulated IL-6 release with increased ARE reporter activity, reduced nuclear factor kappa B (NF-κB) reporter activity, increased GSH production, and stimulated expression of antioxidant genes compared to non-Nrf2 inducer pretreated groups, suggesting that Nrf2 may play a protective role against BDE-47-mediated inflammatory responses in HTR-8/SVneo cells. These results suggest that Nrf2 activation significantly attenuated BDE-47-induced IL-6 release by augmentation of cellular antioxidative system via upregulation of Nrf2 signaling pathways, and that Nrf2 induction may be a potential therapeutic target to reduce adverse pregnancy outcomes associated with toxicant-induced oxidative stress and inflammation. Copyright © 2014 Elsevier Inc. All rights reserved.

  1. Metallothionein Is Downstream of Nrf2 and Partially Mediates Sulforaphane Prevention of Diabetic Cardiomyopathy.

    PubMed

    Gu, Junlian; Cheng, Yanli; Wu, Hao; Kong, Lili; Wang, Shudong; Xu, Zheng; Zhang, Zhiguo; Tan, Yi; Keller, Bradley B; Zhou, Honglan; Wang, Yuehui; Xu, Zhonggao; Cai, Lu

    2017-02-01

    We have reported that sulforaphane (SFN) prevented diabetic cardiomyopathy in both type 1 and type 2 diabetes (T2DM) animal models via the upregulation of nuclear transcription factor erythroid 2-related factor 2 (Nrf2) and metallothionein (MT). In this study, we tested whether SFN protects the heart from T2DM directly through Nrf2, MT, or both. Using Nrf2-knockout (KO), MT-KO, and wild-type (WT) mice, T2DM was induced by feeding a high-fat diet for 3 months followed by a small dose of streptozotocin. Age-matched controls were given a normal diet. Both T2DM and control mice were then treated with or without SFN for 4 months by continually feeding a high-fat or normal diet. SFN prevented diabetes-induced cardiac dysfunction as well as diabetes-associated cardiac oxidative damage, inflammation, fibrosis, and hypertrophy, with increases in Nrf2 and MT expressions in the WT mice. Both Nrf2-KO and MT-KO diabetic mice exhibited greater cardiac damage than WT diabetic mice. SFN did not provide cardiac protection in Nrf2-KO mice, but partially or completely protected the heart from diabetes in MT-KO mice. SFN did not induce MT expression in Nrf2-KO mice, but stimulated Nrf2 function in MT-KO mice. These results suggest that Nrf2 plays the indispensable role for SFN cardiac protection from T2DM with significant induction of MT and other antioxidants. MT expression induced by SFN is Nrf2 dependent, but is not indispensable for SFN-induced cardiac protection from T2DM. © 2017 by the American Diabetes Association.

  2. Britanin Ameliorates Cerebral Ischemia-Reperfusion Injury by Inducing the Nrf2 Protective Pathway.

    PubMed

    Wu, Guozhen; Zhu, Lili; Yuan, Xing; Chen, Hao; Xiong, Rui; Zhang, Shoude; Cheng, Hao; Shen, Yunheng; An, Huazhang; Li, Tiejun; Li, Honglin; Zhang, Weidong

    2017-10-10

    Oxidative stress is considered the major cause of tissue injury after cerebral ischemia. The nuclear factor erythroid 2-related factor 2 (Nrf2) pathway is one of the most important defensive mechanisms against oxidative stresses and has been confirmed as a target for stroke treatment. Thus, we desired to find new Nrf2 activators and test their neuronal protective activity both in vivo and in vitro. The herb-derived compound, Britanin, is a potent inducer of the Nrf2 system. Britanin can induce the expression of protective enzymes and reverse oxygen-glucose deprivation, followed by reperfusion (OGD-R)-induced neuronal injury in primary cortical neurons in vitro. Furthermore, the administration of Britanin significantly ameliorated middle cerebral artery occlusion-reperfusion (MCAO-R) insult in vivo. We report here the crystal structure of the complex of Britanin and the BTB domain of Keap1. Britanin selectively binds to a conserved cysteine residue, cysteine 151, of Keap1 and inhibits Keap1-mediated ubiquitination of Nrf2, leading to induction of the Nrf2 pathway. Britanin is a potent inducer of Nrf2. The complex crystal structure of Britanin and the BTB domain of Keap1 help clarify the mechanism of Nrf2 induction. Britanin was proven to protect primary cortical neurons against OGD-R-induced injury in an Nrf2-dependant way. Additionally, Britanin had excellent cerebroprotective effect in an MCAO-R model. Our results demonstrate that the natural product Britanin with potent Nrf2-activating and neural protective activities both in vitro and in vivo could be developed into a cerebroprotective therapeutic agent. Antioxid. Redox Signal. 27, 754-768.

  3. Nuclear Respiratory Factor-1 (NRF-1) Gene Expression in Chronic Kidney Disease Patients Undergoing Hemodialysis and Mitochondrial Oxidative Dysregulation.

    PubMed

    Hashad, Doaa; Elgohry, Iman; Dwedar, Fatma

    2016-11-01

    Chronic kidney disease (CKD) is characterized by progressive irreversible deterioration of renal functions. Advanced stages of CKD are associated with oxidative stress due to the imbalance between oxidant production and antioxidant defense mechanisms. Survival of patients with end stage renal diseases is maintained on variable forms of renal replacement therapies (RRT) which include peritoneal dialysis, hemodialysis, and sometimes renal transplantation. In humans, Nuclear Respiratory Factor 1 (NRF-1) gene encodes for a transcription factor that, together with the transcriptional co-activator encoded by Peroxisome Proliferator activated Receptor Gamma coactivator 1 Alpha (PGC1-a) gene, stimulates the expression of a broad set of nuclear genes (as COX6C) which are involved in mitochondrial biogenesis and functions. As mitochondria are considered a major source of reactive oxidant species, the objective of the present study was to assess mitochondrial oxidative dysregulation occurring in chronic kidney disease patients undergoing hemodialysis employing NRF-1 and COX6C genes' expression as an indicator of mitochondrial oxidative metabolism. Forty-nine chronic kidney disease patients undergoing intermittent hemodialysis were included in the present study. A group of thirty-three age- and gender- matched healthy volunteers served as a control group. Assessment of expression of NRF-1 and COX6C genes was performed using quantitative real-time PCR technique. NRF-1 and COX6C expression showed a statistically significant difference between both studied groups being down-regulated in CKD patients. In addition, malondialdehyde (MDA) levels were higher in patients on hemodialysis indicating lipid peroxidation. A negative correlation was detected between MDA level and expression of both NRF-1 and COX6C genes. Chronic kidney disease patients undergoing hemodialysis might be subjected to potential mitochondrial oxidative dysregulation with subsequent possible vascular and tissue

  4. Activation of the NRF2 pathway and its impact on the prognosis of anaplastic glioma patients

    PubMed Central

    Kanamori, Masayuki; Higa, Tsuyoshi; Sonoda, Yukihiko; Murakami, Shohei; Dodo, Mina; Kitamura, Hiroshi; Taguchi, Keiko; Shibata, Tatsuhiro; Watanabe, Mika; Suzuki, Hiroyoshi; Shibahara, Ichiyo; Saito, Ryuta; Yamashita, Yoji; Kumabe, Toshihiro; Yamamoto, Masayuki; Motohashi, Hozumi; Tominaga, Teiji

    2015-01-01

    Background Nuclear factor erythroid 2–related factor 2 (NRF2) plays pivotal roles in cytoprotection. We aimed at clarifying the contribution of the NRF2 pathway to malignant glioma pathology. Methods NRF2 target gene expression and its association with prognosis were examined in 95 anaplastic gliomas with or without isocitrate dehydrogenase (IDH) 1/2 gene mutations and 52 glioblastomas. To explore mechanisms for the altered activity of the NRF2 pathway, we examined somatic mutations and expressions of the NRF2 gene and those encoding NRF2 regulators, Kelch-like ECH-associated protein 1 (KEAP1) and p62/SQSTSM. To clarify the functional interaction between IDH1 mutations and the NRF2 pathway, we introduced a mutant IDH1 to T98 glioblastoma-derived cells and examined the NRF2 activity in these cells. Results NRF2 target genes were elevated in 13.7% and 32.7% of anaplastic gliomas and glioblastomas, respectively. Upregulation of NRF2 target genes correlated with poor prognosis in anaplastic gliomas but not in glioblastomas. Neither somatic mutations of NRF2/KEAP1 nor dysregulated expression of KEAP1/p62 explained the increased expression of NRF2 target genes. In most cases of anaplastic glioma with mutated IDH1/2, NRF2 and its target genes were downregulated. This was reproducible in IDH1 R132H–expressing T98 cells. In minor cases of IDH1/2-mutant anaplastic gliomas with increased expression of NRF2 target genes, the clinical outcomes were significantly poor. Conclusions The NRF2 activity is increased in a significant proportion of malignant gliomas in general but decreased in the majority of IDH1/2-mutant anaplastic gliomas. It is plausible that the NRF2 pathway plays an important role in tumor progression of anaplastic gliomas with IDH1/2 mutations. PMID:25304134

  5. Nrf2 protects photoreceptor cells from photo-oxidative stress induced by blue light.

    PubMed

    Chen, Wan-Ju; Wu, Caiying; Xu, Zhenhua; Kuse, Yoshiki; Hara, Hideaki; Duh, Elia J

    2017-01-01

    Oxidative stress plays a key role in age-related macular degeneration and hereditary retinal degenerations. Light damage in rodents has been used extensively to model oxidative stress-induced photoreceptor degeneration, and photo-oxidative injury from blue light is particularly damaging to photoreceptors. The endogenous factors protecting photoreceptors from oxidative stress, including photo-oxidative stress, are continuing to be elucidated. In this study, we evaluated the effect of blue light exposure on photoreceptors and its relationship to Nrf2 using cultured murine photoreceptor (661W) cells. 661W cells were exposed to blue light at 2500 lux. Exposure to blue light for 6-24 h resulted in a significant increase in intracellular reactive oxygen species (ROS) and death of 661W cells in a time-dependent fashion. Blue light exposure resulted in activation of Nrf2, as indicated by an increase in nuclear translocation of Nrf2. This was associated with a significant induction of expression of Nrf2 as well as an array of Nrf2 target genes, including antioxidant genes, as indicated by quantitative reverse transcription PCR (qRT-PCR). In order to determine the functional role of Nrf2, siRNA-mediated knockdown studies were performed. Nrf2-knockdown in 661W cells resulted in significant exacerbation of blue light-induced reactive oxygen species levels as well as cell death. Taken together, these findings indicate that Nrf2 is an important endogenous protective factor against oxidative stress in photoreceptor cells. This suggests that drugs targeting Nrf2 could be considered as a neuroprotective strategy for photoreceptors in AMD and other retinal conditions. Copyright © 2016 Elsevier Ltd. All rights reserved.

  6. ROS enhance angiogenic properties via regulation of NRF2 in tumor endothelial cells

    PubMed Central

    Towfik, Alam Mohammad; Akiyama, Kosuke; Ohga, Noritaka; Shindoh, Masanobu; Hida, Yasuhiro; Minowa, Kazuyuki; Fujisawa, Toshiaki; Hida, Kyoko

    2017-01-01

    Reactive oxygen species (ROS) are unstable molecules that activate oxidative stress. Because of the insufficient blood flow in tumors, the tumor microenvironment is often exposed to hypoxic condition and nutrient deprivation, which induces ROS accumulation. We isolated tumor endothelial cells (TECs) and found that they have various abnormalities, although the underlying mechanisms are not fully understood. Here we showed that ROS were accumulated in tumor blood vessels and ROS enhanced TEC migration with upregulation of several angiogenesis related gene expressions. It was also demonstrated that these genes were upregulated by regulation of Nuclear factor erythroid 2-related factor 2 (NRF2). Among these genes, we focused on Biglycan, a small leucine-rich proteoglycan. Inhibition of Toll-like receptors 2 and 4, known BIGLYCAN (BGN) receptors, cancelled the TEC motility stimulated by ROS. ROS inhibited NRF2 expression in TECs but not in NECs, and NRF2 inhibited phosphorylation of SMAD2/3, which activates transcription of BGN. These results indicated that ROS-induced BGN caused the pro-angiogenic phenotype in TECs via NRF2 dysregulation. PMID:28525375

  7. Sulforaphane and Other Nutrigenomic Nrf2 Activators: Can the Clinician's Expectation Be Matched by the Reality?

    PubMed

    Houghton, Christine A; Fassett, Robert G; Coombes, Jeff S

    2016-01-01

    The recognition that food-derived nonnutrient molecules can modulate gene expression to influence intracellular molecular mechanisms has seen the emergence of the fields of nutrigenomics and nutrigenetics. The aim of this review is to describe the properties of nutrigenomic activators of transcription factor Nrf2 (nuclear factor erythroid 2-related factor 2), comparing the potential for sulforaphane and other phytochemicals to demonstrate clinical efficacy as complementary medicines. Broccoli-derived sulforaphane emerges as a phytochemical with this capability, with oral doses capable of favourably modifying genes associated with chemoprevention. Compared with widely used phytochemical-based supplements like curcumin, silymarin, and resveratrol, sulforaphane more potently activates Nrf2 to induce the expression of a battery of cytoprotective genes. By virtue of its lipophilic nature and low molecular weight, sulforaphane displays significantly higher bioavailability than the polyphenol-based dietary supplements that also activate Nrf2. Nrf2 activation induces cytoprotective genes such as those playing key roles in cellular defense mechanisms including redox status and detoxification. Both its high bioavailability and significant Nrf2 inducer capacity contribute to the therapeutic potential of sulforaphane-yielding supplements.

  8. Systems-Level Feedbacks of NRF2 Controlling Autophagy upon Oxidative Stress Response

    PubMed Central

    Kapuy, Orsolya; Papp, Diána; Bánhegyi, Gábor

    2018-01-01

    Although the primary role of autophagy-dependent cellular self-eating is cytoprotective upon various stress events (such as starvation, oxidative stress, and high temperatures), sustained autophagy might lead to cell death. A transcription factor called NRF2 (nuclear factor erythroid-related factor 2) seems to be essential in maintaining cellular homeostasis in the presence of either reactive oxygen or nitrogen species generated by internal metabolism or external exposure. Accumulating experimental evidence reveals that oxidative stress also influences the balance of the 5′ AMP-activated protein kinase (AMPK)/rapamycin (mammalian kinase target of rapamycin or mTOR) signaling pathway, thereby inducing autophagy. Based on computational modeling here we propose that the regulatory triangle of AMPK, NRF2 and mTOR guaranties a precise oxidative stress response mechanism comprising of autophagy. We suggest that under conditions of oxidative stress, AMPK is crucial for autophagy induction via mTOR down-regulation, while NRF2 fine-tunes the process of autophagy according to the level of oxidative stress. We claim that the cellular oxidative stress response mechanism achieves an incoherently amplified negative feedback loop involving NRF2, mTOR and AMPK. The mTOR-NRF2 double negative feedback generates bistability, supporting the proper separation of two alternative steady states, called autophagy-dependent survival (at low stress) and cell death (at high stress). In addition, an AMPK-mTOR-NRF2 negative feedback loop suggests an oscillatory characteristic of autophagy upon prolonged intermediate levels of oxidative stress, resulting in new rounds of autophagy stimulation until the stress events cannot be dissolved. Our results indicate that AMPK-, NRF2- and mTOR-controlled autophagy induction provides a dynamic adaptation to altering environmental conditions, assuming their new frontier in biomedicine. PMID:29510589

  9. Protective effect of nuclear factor E2-related factor 2 on inflammatory cytokine response to brominated diphenyl ether-47 in the HTR-8/SVneo human first trimester extravillous trophoblast cell line

    DOE Office of Scientific and Technical Information (OSTI.GOV)

    Park, Hae-Ryung, E-mail: heaven@umich.edu; Loch-Caruso, Rita

    Polybrominated diphenyl ethers (PBDEs) are widely used flame retardants, and BDE-47 is a prevalent PBDE congener detected in human tissues. Exposure to PBDEs has been linked to adverse pregnancy outcomes in humans. Although the underlying mechanisms of adverse birth outcomes are poorly understood, critical roles for oxidative stress and inflammation are implicated. The present study investigated antioxidant responses in a human extravillous trophoblast cell line, HTR-8/SVneo, and examined the role of nuclear factor E2-related factor 2 (Nrf2), an antioxidative transcription factor, in BDE-47-induced inflammatory responses in the cells. Treatment of HTR-8/SVneo cells with 5, 10, 15, and 20 μM BDE-47more » for 24 h increased intracellular glutathione (GSH) levels compared to solvent control. Treatment of HTR-8/SVneo cells with 20 μM BDE-47 for 24 h induced the antioxidant response element (ARE) activity, indicating Nrf2 transactivation by BDE-47 treatment, and resulted in differential expression of redox-sensitive genes compared to solvent control. Pretreatment with tert-butyl hydroquinone (tBHQ) or sulforaphane, known Nrf2 inducers, reduced BDE-47-stimulated IL-6 release with increased ARE reporter activity, reduced nuclear factor kappa B (NF-κB) reporter activity, increased GSH production, and stimulated expression of antioxidant genes compared to non-Nrf2 inducer pretreated groups, suggesting that Nrf2 may play a protective role against BDE-47-mediated inflammatory responses in HTR-8/SVneo cells. These results suggest that Nrf2 activation significantly attenuated BDE-47-induced IL-6 release by augmentation of cellular antioxidative system via upregulation of Nrf2 signaling pathways, and that Nrf2 induction may be a potential therapeutic target to reduce adverse pregnancy outcomes associated with toxicant-induced oxidative stress and inflammation. - Highlights: • BDE-47 stimulated ARE reporter activity and GSH production. • BDE-47 resulted in differential

  10. Targeting NRF2 signaling for cancer chemoprevention

    DOE Office of Scientific and Technical Information (OSTI.GOV)

    Kwak, Mi-Kyoung, E-mail: mkwak@ynu.ac.k; Kensler, Thomas W.

    2010-04-01

    Modulation of the metabolism and disposition of carcinogens through induction of cytoprotective enzymes is one of several promising strategies to prevent cancer. Chemopreventive efficacies of inducers such as dithiolethiones and sulforaphane have been extensively studied in animals as well as in humans. The KEAP1-NRF2 system is a key, but not unilateral, molecular target for these chemopreventive agents. The transcription factor NRF2 (NF-E2-related factor 2) is a master regulator of the expression of a subset of genes, which produce proteins responsible for the detoxication of electrophiles and reactive oxygen species as well as the removal or repair of some of theirmore » damage products. It is believed that chemopreventive enzyme inducers affect the interaction between KEAP1 and NRF2 through either mediating conformational changes of the KEAP1 protein or activating phosphorylation cascades targeting the KEAP1-NRF2 complex. These events in turn affect NRF2 stability and trafficking. Recent advances elucidating the underlying structural biology of KEAP1-NRF2 signaling and identification of the gene clusters under the transcriptional control of NRF2 are facilitating understanding of the potential pleiotropic effects of NRF2 activators and discovery of novel classes of potent chemopreventive agents such as the triterpenoids. Although there is appropriately a concern regarding a deleterious role of the KEAP1-NRF2 system in cancer cell biology, especially as the pathway affects cell survival and drug resistance, the development and the use of NRF2 activators as chemopreventive agents still holds a great promise for protection of normal cells from a diversity of environmental stresses that contribute to the burden of cancer and other chronic, degenerative diseases.« less

  11. Selenium antagonizes cadmium-induced apoptosis in chicken spleen but not involving Nrf2-regulated antioxidant response.

    PubMed

    Chen, Menghao; Li, Xiaojing; Fan, Ruifeng; Cao, Changyu; Yao, Haidong; Xu, Shiwen

    2017-11-01

    The nuclear transcription factor NF-E2-related factor 2 (Nrf2) binds to antioxidant response elements (AREs) and is involved in the regulation of genes participated in defending cells against oxidative damage, which have been confirmed in animal models. Selenium (Se), known as an important element in the regulation of antioxidant activity, can antagonize Cadmium (Cd) toxicity in birds. However, the role of Nrf2 in selenium-cadmium interaction has not been reported in birds. To further explore the mechanism of selenium attenuating spleen toxicity induced by cadmium in chickens, cadmium chloride (CdCl 2 , 150mg/kg) and sodium selenite (Na 2 SeO 3 , 2mg/kg) were co-administrated or individually administered in the diet of chickens for 90 days. The results showed that Cd exposure increased the level of hydrogen peroxide (H 2 O 2 ) and malondialdehyde (MDA) and decreased the antioxidant enzyme activities, including superoxide dismutase (SOD), glutathione peroxidase (Gpx), total antioxidative capacity (T-AOC), catalase (CAT). Cd exposure increased obviously nuclear accumulation of Nrf2, and the expression of Nrf2 downstream heme oxygenase-1 (HO-1) and NAD(P)H: quinine oxidoreductase 1 (NQO1), reduced the expression of Kelch-like ECH-associated protein (keap1), Gpx-1 and thioredoxin reductase-1 (TrxR1). In addition, Cd induced the increase of bak, caspase9, p53, Cyt c mRNA levels, increased bax/bcl-2 ratio, increased caspase3 mRNA and protein levels. Selenium treatment reduced the accumulation of Cd in the spleen, attenuates Cd-induced Nrf2 nuclear accumulation, enhanced antioxidant enzyme activities, ameliorated Cd-induced oxidative stress and apoptosis in the spleen. In summary, our results demonstrate that Se ameliorated spleen toxicity induced by cadmium by modulating the antioxidant system, independently of Nrf2-regulated antioxidant response pathway. Copyright © 2017 Elsevier Inc. All rights reserved.

  12. Targeting the Transcription Factor Nrf2 to Ameliorate Oxidative Stress and Inflammation in Chronic Kidney Disease

    PubMed Central

    Ruiz, Stacey; Pergola, Pablo E.; Zager, Richard A.; Vaziri, Nosratola D.

    2012-01-01

    Oxidative stress and inflammation are mediators in the development and progression of chronic kidney disease (CKD) and its complications, and they are inseparably linked as each begets and amplifies the other. CKD-associated oxidative stress is due to increased production of reactive oxygen species (ROS) and diminished antioxidant capacity. The latter is largely caused by impaired activation of Nrf2, the transcription factor that regulates genes encoding antioxidant and detoxifying molecules. Protective effects of Nrf2 are evidenced by amelioration of oxidative stress, inflammation, and kidney disease in response to natural Nrf2 activators in animal models, while Nrf2 deletion amplifies these pathogenic pathways and leads to autoimmune nephritis. Given the role of impaired Nrf2 activity in CKD-induced oxidative stress and inflammation, interventions aimed at restoring Nrf2 may be effective in retarding CKD progression. Clinical trials of the potent Nrf2 activator bardoxolone methyl showed significant improvement in renal function in CKD patients with type 2 diabetes. Results of the ongoing BEACON trial investigating the effect of this drug on time to end-stage renal disease or cardiovascular death will help further characterize the efficacy of Nrf2 pharmacological modulation in CKD. This article provides an overview of the role of impaired Nrf2 activity in the pathogenesis of CKD-associated oxidative stress and inflammation and the potential utility of targeting Nrf2 in the treatment of CKD. PMID:23325084

  13. Gestational Diabetes Mellitus Impairs Nrf2-Mediated Adaptive Antioxidant Defenses and Redox Signaling in Fetal Endothelial Cells In Utero

    PubMed Central

    Cheng, Xinghua; Chapple, Sarah J.; Patel, Bijal; Puszyk, William; Sugden, David; Yin, Xiaoke; Mayr, Manuel; Siow, Richard C.M.; Mann, Giovanni E.

    2013-01-01

    In utero exposure to gestational diabetes mellitus (GDM) is associated with an increased risk of type 2 diabetes and cardiovascular disease in later life, yet the underlying mechanisms remain to be elucidated. We examined the effects of GDM on the proteome, redox status, and nuclear factor erythroid 2–related factor 2 (Nrf2)-mediated antioxidant gene expression in human fetal endothelial cells. Proteomic analysis revealed that proteins involved in redox homeostasis were significantly altered in GDM and associated with increased mitochondrial superoxide generation, protein oxidation, DNA damage, and diminished glutathione (GSH) synthesis. In GDM cells, the lipid peroxidation product 4-hydroxynonenal (HNE) failed to induce nuclear Nrf2 accumulation and mRNA and/or protein expression of Nrf2 and its target genes NAD(P)H:quinone oxidoreductase 1 (NQO1), Bach1, cystine/glutamate transporter, and glutamate cysteine ligase. Although methylation of CpG islands in Nrf2 or NQO1 promoters was unaltered by GDM, decreased DJ-1 and increased phosphorylated glycogen synthase kinase 3β levels may account for impaired Nrf2 signaling. HNE-induced increases in GSH and NQO1 levels were abrogated by Nrf2 small interfering RNA in normal cells, and overexpression of Nrf2 in GDM cells partially restored NQO1 induction. Dysregulation of Nrf2 in fetal endothelium may contribute to the increased risk of type 2 diabetes and cardiovascular disease in offspring. PMID:23974919

  14. Novel Nrf2 activators from microbial transformation products inhibit blood-retinal barrier permeability in rabbits.

    PubMed

    Nakagami, Yasuhiro; Masuda, Kayoko; Hatano, Emiko; Inoue, Tatsuya; Matsuyama, Takuya; Iizuka, Mayumi; Ono, Yasunori; Ohnuki, Takashi; Murakami, Yoko; Iwasaki, Masaru; Yoshida, Kazuhiro; Kasuya, Yuji; Komoriya, Satoshi

    2015-03-01

    Nuclear factor erythroid 2-related factor 2 (Nrf2) is a redox-sensitive transcription factor that binds to antioxidant response elements located in the promoter region of genes encoding many antioxidant enzymes and phase II detoxifying enzymes. Activation of the Nrf2 pathway seems protective for many organs, and although a well-known Nrf2 activator, bardoxolone methyl, was evaluated clinically for treating chronic kidney disease, it was found to induce adverse events. Many bardoxolone methyl derivatives, mostly derived by chemical modifications, have already been studied. However, we adopted a biotransformation technique to obtain a novel Nrf2 activator. The potent novel Nrf2 activator, RS9, was obtained from microbial transformation products. Its Nrf2 activity was evaluated by determining NADPH:quinone oxidoreductase-1 induction activity in Hepa1c1c7 cells. We also investigated the effects of RS9 on oxygen-induced retinopathy in rats and glycated albumin-induced blood-retinal barrier permeability in rabbits because many ocular diseases are associated with oxidative stress and inflammation. Bardoxolone methyl doubled the specific activity of Nrf2 in Hepa1c1c7 cells at a much higher concentration than RS9. Moreover, the induction of Nrf2-targeted genes was observed at a one-tenth lower concentration of RS9. Interestingly, the cytotoxicity of RS9 was substantially reduced compared with bardoxolone methyl. Oral and intravitreal administration of RS9 ameliorated the pathological scores and leakage in the models of retinopathy in rats and ocular inflammation in rabbits respectively. Nrf2 activators are applicable for treating ocular diseases and novel Nrf2 activators have potential as a unique method for prevention and treatment of retinovascular disease. © 2014 The British Pharmacological Society.

  15. Novel Nrf2 activators from microbial transformation products inhibit blood–retinal barrier permeability in rabbits

    PubMed Central

    Nakagami, Yasuhiro; Masuda, Kayoko; Hatano, Emiko; Inoue, Tatsuya; Matsuyama, Takuya; Iizuka, Mayumi; Ono, Yasunori; Ohnuki, Takashi; Murakami, Yoko; Iwasaki, Masaru; Yoshida, Kazuhiro; Kasuya, Yuji; Komoriya, Satoshi

    2015-01-01

    Background and Purpose Nuclear factor erythroid 2-related factor 2 (Nrf2) is a redox-sensitive transcription factor that binds to antioxidant response elements located in the promoter region of genes encoding many antioxidant enzymes and phase II detoxifying enzymes. Activation of the Nrf2 pathway seems protective for many organs, and although a well-known Nrf2 activator, bardoxolone methyl, was evaluated clinically for treating chronic kidney disease, it was found to induce adverse events. Many bardoxolone methyl derivatives, mostly derived by chemical modifications, have already been studied. However, we adopted a biotransformation technique to obtain a novel Nrf2 activator. Experimental Approach The potent novel Nrf2 activator, RS9, was obtained from microbial transformation products. Its Nrf2 activity was evaluated by determining NADPH:quinone oxidoreductase-1 induction activity in Hepa1c1c7 cells. We also investigated the effects of RS9 on oxygen-induced retinopathy in rats and glycated albumin-induced blood–retinal barrier permeability in rabbits because many ocular diseases are associated with oxidative stress and inflammation. Key Results Bardoxolone methyl doubled the specific activity of Nrf2 in Hepa1c1c7 cells at a much higher concentration than RS9. Moreover, the induction of Nrf2-targeted genes was observed at a one-tenth lower concentration of RS9. Interestingly, the cytotoxicity of RS9 was substantially reduced compared with bardoxolone methyl. Oral and intravitreal administration of RS9 ameliorated the pathological scores and leakage in the models of retinopathy in rats and ocular inflammation in rabbits respectively. Conclusion and Implications Nrf2 activators are applicable for treating ocular diseases and novel Nrf2 activators have potential as a unique method for prevention and treatment of retinovascular disease. PMID:25363737

  16. Characterization of the Potent, Selective Nrf2 Activator, 3-(Pyridin-3-Ylsulfonyl)-5-(Trifluoromethyl)-2H-Chromen-2-One, in Cellular and In Vivo Models of Pulmonary Oxidative Stress.

    PubMed

    Yonchuk, John G; Foley, Joseph P; Bolognese, Brian J; Logan, Gregory; Wixted, William E; Kou, Jen-Pyng; Chalupowicz, Diana G; Feldser, Heidi G; Sanchez, Yolanda; Nie, Hong; Callahan, James F; Kerns, Jeffrey K; Podolin, Patricia L

    2017-10-01

    Nuclear factor (erythroid-derived 2)-like 2 (Nrf2) is a key regulator of oxidative stress and cellular repair and can be activated through inhibition of its cytoplasmic repressor, Kelch-like ECH-associated protein 1 (Keap1). Several small molecule disrupters of the Nrf2-Keap1 complex have recently been tested and/or approved for human therapeutic use but lack either potency or selectivity. The main goal of our work was to develop a potent, selective activator of NRF2 as protection against oxidative stress. In human bronchial epithelial cells, our Nrf2 activator, 3-(pyridin-3-ylsulfonyl)-5-(trifluoromethyl)-2 H -chromen-2-one (PSTC), induced Nrf2 nuclear translocation, Nrf2-regulated gene expression, and downstream signaling events, including induction of NAD(P)H:quinone oxidoreductase 1 (NQO1) enzyme activity and heme oxygenase-1 protein expression, in an Nrf2-dependent manner. As a marker of subsequent functional activity, PSTC restored oxidant ( tert -butyl hydroperoxide)-induced glutathione depletion. The compound's engagement of the Nrf2 signaling pathway translated to an in vivo setting, with induction of Nrf2-regulated gene expression and NQO1 enzyme activity, as well as restoration of oxidant (ozone)-induced glutathione depletion, occurring in the lungs of PSTC-treated rodents. Under disease conditions, PSTC engaged its target, inducing the expression of Nrf2-regulated genes in human bronchial epithelial cells derived from patients with chronic obstructive pulmonary disease, as well as in the lungs of cigarette smoke-exposed mice. Subsequent to the latter, a dose-dependent inhibition of cigarette smoke-induced pulmonary inflammation was observed. Finally, in contrast with bardoxolone methyl and sulforaphane, PSTC did not inhibit interleukin-1 β -induced nuclear factor- κ B translocation or insulin-induced S6 phosphorylation in human cells, emphasizing the on-target activity of this compound. In summary, we characterize a potent, selective Nrf2 activator

  17. Polydatin promotes Nrf2-ARE anti-oxidative pathway through activating Sirt1 to resist AGEs-induced upregulation of fibronetin and transforming growth factor-β1 in rat glomerular messangial cells.

    PubMed

    Huang, Kaipeng; Chen, Cheng; Hao, Jie; Huang, Junying; Wang, Shaogui; Liu, Peiqing; Huang, Heqing

    2015-01-05

    Sirt1 and nuclear factor-E2 related factor 2 (Nrf2)-anti-oxidant response element (ARE) anti-oxidative pathway play important regulatory roles in the pathological progression of diabetic nephropathy (DN) induced by advanced glycation-end products (AGEs). Polydatin (PD), a glucoside of resveratrol, has been shown to possess strong anti-oxidative bioactivity. Our previous study demonstrated that PD markedly resists the progression of diabetic renal fibrosis and thus, inhibits the development of DN. Whereas, whether PD could resist DN through regulating Sirt1 and consequently promoting Nrf2-ARE pathway needs further investigation. Here, we found that concomitant with decreasing RAGE (the specific receptor for AGEs) expression, PD significantly reversed the downregulation of Sirt1 in terms of protein expression and deacetylase activity and attenuated FN and TGF-β1 expression in GMCs exposed to AGEs. Under AGEs-treatment condition, PD could decrease Keap1 expression and promote the nuclear content, ARE-binding ability, and transcriptional activity of Nrf2. In addition, PD increased the protein levels of heme oxygenase 1 (HO-1) and superoxide dismutase 1 (SOD1), two target genes of Nrf2. The activation of Nrf2-ARE pathway by PD eventually led to the quenching of ROS overproduction sharply boosted by AGEs. Depletion of Sirt1 blocked Nrf2-ARE pathway activation and reversed FN and TGF-β1 downregulation induced by PD in GMCs challenged with AGEs. Along with reducing HO-1 and SOD1 expression, silencing of Nrf2 increased FN and TGF-β1 levels. PD treatment elevated Sirt1 and Nrf2 levels in the kidney tissues of diabetic rats, then improved the anti-oxidative capacity and renal dysfunction of diabetic models, and finally reversed the upregulation of FN and TGF-β1. Taken together, the resistance of PD on upregulated FN and TGF-β1 induced by AGEs via oxidative stress in GMCs is closely associated with its activation of Sirt1-Nrf2-ARE pathway. Copyright © 2014 Elsevier

  18. Recent Updates on Acetaminophen Hepatotoxicity: The Role of Nrf2 in Hepatoprotection

    PubMed Central

    Gum, Sang Il

    2013-01-01

    Acetaminophen (APAP) known as paracetamol is the main ingredient in Tylenol, which has analgesic and anti-pyretic properties. Inappropriate use of APAP causes major morbidity and mortality secondary to hepatic failure. Overdose of APAP depletes the hepatic glutathione (GSH) rapidly, and the metabolic intermediate leads to hepatocellular death. This article reviews the mechanisms of hepatotoxicity and provides an overview of current research studies. Pharmacokinetics including metabolism (activation and detoxification), subsequent transport (efflux)-facilitating excretion, and some other aspects related to toxicity are discussed. Nuclear factor erythroid 2-related factor 2 (Nrf2)-regulated gene battery plays a critical role in the multiple steps associated with the mitigation of APAP toxicity. The role of Nrf2 as a protective target is described, and potential natural products inhibiting APAP toxicity are outlined. This review provides an update on the mechanism of APAP toxicity and highlights the beneficial role of Nrf2 and specific natural products in hepatoprotection. PMID:24386516

  19. Nrf2/P-glycoprotein axis is associated with clinicopathological characteristics in colorectal cancer.

    PubMed

    Sadeghi, Mohammad Reza; Jeddi, Farhad; Soozangar, Narges; Somi, Mohammad Hossein; Shirmohamadi, Masoud; Khaze, Vahid; Samadi, Nasser

    2018-08-01

    Colorectal cancer (CRC) is the fourth leading cause of cancer-related death worldwide. Activation of ABCB1 gene and its main product, P-glycoprotein, is the common reason for chemoresistance. The nuclear factor-erythroid 2-related factor2 (Nrf2) is directly regulated by Kelch like ECH-associated protein1 (Keap1). In addition, Nrf2 is a key transcriptional factor that regulates efflux transporters, including P-gp. The aim of this study was to investigate the expression levels of Nrf2, Keap1 and ABCB1 in the biopsy samples and their association with clinicopathological features in CRC patients. Both mRNA and protein expression levels were measured by Real-time PCR and immunohistochemistry (IHC), respectively, in biopsies from colonoscopy in 65 CRC patients compared to those in 65 non-CRC individuals. While expression levels of Nrf2 and ABCB1 (P-gp) were markedly higher in both mRNA and protein levels in CRC biopsies (p < 0.01), Keap1 expression level was significantly lower in these samples (p < 0.05). Positive correlations between Nrf2 expression level and tumor size (p = 0.003), lymph node (p = 0.038), distant metastasis (p = 0.008), and smoking status (p = 0.02) were observed. However, P-gp expression was associated only with patient age and smoking status. In addition, there was a positive correlation between protein levels of Nrf2 and P-gp, in both CRC (r = 0.617, p < 0.001) and non-CRC tissues (r = 0.930, p < 0.001). In conclusion, over-expression of Nrf2 and ABCB1/P-gp, as well as down-regulation of mRNA expression level of Keap1 in CRC patients denotes the role of Keap1/Nrf2/ABCB1 axis in CRC progression and chemoresistance. Our data suggest that therapeutic inhibition of Nrf2/ABCB1 signaling can be considered as a novel strategy to improve the efficacy of chemotherapeutics against CRC. Copyright © 2018 Elsevier Masson SAS. All rights reserved.

  20. Luteolin inhibits the Nrf2 signaling pathway and tumor growth in vivo

    DOE Office of Scientific and Technical Information (OSTI.GOV)

    Chian, Song; Thapa, Ruby; Chi, Zhexu

    Highlights: • Luteolin inhibits the Nrf2 pathway in mouse liver and in xenografted tumors. • Luteolin markedly inhibits the growth of xenograft tumors. • Luteolin enhances the anti-cancer effect of cisplatin in mice in vivo. • Luteolin could serve as an adjuvant in the chemotherapy of NSCLC. - Abstract: Nuclear factor erythroid 2-related factor 2 (Nrf2) is over-expressed in many types of tumor, promotes tumor growth, and confers resistance to anticancer therapy. Hence, Nrf2 is regarded as a novel therapeutic target in cancer. Previously, we reported that luteolin is a strong inhibitor of Nrf2 in vitro. Here, we showed thatmore » luteolin reduced the constitutive expression of NAD(P)H quinone oxidoreductase 1 in mouse liver in a time- and dose-dependent manner. Further, luteolin inhibited the expression of antioxidant enzymes and glutathione transferases, decreasing the reduced glutathione in the liver of wild-type mice under both constitutive and butylated hydroxyanisole-induced conditions. In contrast, such distinct responses were not detected in Nrf2{sup −/−} mice. In addition, oral administration of luteolin, either alone or combined with intraperitoneal injection of the cytotoxic drug cisplatin, greatly inhibited the growth of xenograft tumors from non-small-cell lung cancer (NSCLC) cell line A549 cells grown subcutaneously in athymic nude mice. Cell proliferation, the expression of Nrf2, and antioxidant enzymes were all reduced in tumor xenograft tissues. Furthermore, luteolin enhanced the anti-cancer effect of cisplatin. Together, our findings demonstrated that luteolin inhibits the Nrf2 pathway in vivo and can serve as an adjuvant in the chemotherapy of NSCLC.« less

  1. Minocycline attenuates sevoflurane-induced cell injury via activation of Nrf2.

    PubMed

    Tian, Yue; Wu, Xiuying; Guo, Shanbin; Ma, Ling; Huang, Wei; Zhao, Xiaochun

    2017-04-01

    Minocycline has been demonstrated to exert neuroprotective effects in various experimental models. In the present study, we investigated the mechanisms underlying the protective effects of minocycline on cell injury induced by the inhalation of the anesthetic, sevoflurane. In our in vivo experiments using rats, minocycline attenuated sevoflurane-induced neuronal degeneration and apoptosis in the rat hippocampus, and this effect was associated with the minocycline-mediated suppression of oxidative stress in the hippocampus. In in vitro experiments, minocycline inhibited sevoflurane-induced apoptosis and the production of reactive oxygen species (ROS) in H4 human neuroglioma cells. In addition, minocycline suppressed the sevoflurane-induced upregulation of interleukin (IL)-6 and the activation of the nuclear factor-κB (NF-κB) signaling pathway in H4 cells. Furthermore, we found that nuclear factor E2-related factor 2 (Nrf2), an activator of the stress response, was upregulated and activated upon sevoflurane treatment both in the rat hippocampus and in H4 cells. In addition, minocycline further augmented the upregulation and activation of Nrf2 when used in conjunction with sevoflurane. Moreover, the knockdown of Nrf2 in H4 cells by small interfering RNA (siRNA) diminished the cytoprotective effect of minocycline, and attenuated the inhibitory effect of minocycline on ROS production, IL-6 upregulation and the activation of the NF-κB signaling pathway. On the whole, our findings indicate that minocycline may exert protective effects against sevoflurane-induced cell injury via the Nrf2-modulated antioxidant response and the inhibition of the activation of the NF-κB signaling pathway.

  2. DJ-1 Modulates Nuclear Erythroid 2-Related Factor-2-Mediated Protection in Human Primary Alveolar Type II Cells in Smokers.

    PubMed

    Bahmed, Karim; Messier, Elise M; Zhou, Wenbo; Tuder, Rubin M; Freed, Curt R; Chu, Hong Wei; Kelsen, Steven G; Bowler, Russell P; Mason, Robert J; Kosmider, Beata

    2016-09-01

    Cigarette smoke (CS) is a main source of oxidative stress and a key risk factor for emphysema, which consists of alveolar wall destruction. Alveolar type (AT) II cells are in the gas exchange regions of the lung. We isolated primary ATII cells from deidentified organ donors whose lungs were not suitable for transplantation. We analyzed the cell injury obtained from nonsmokers, moderate smokers, and heavy smokers. DJ-1 protects cells from oxidative stress and induces nuclear erythroid 2-related factor-2 (Nrf2) expression, which activates the antioxidant defense system. In ATII cells isolated from moderate smokers, we found DJ-1 expression by RT-PCR, and Nrf2 and heme oxygenase (HO)-1 translocation by Western blotting and immunocytofluorescence. In ATII cells isolated from heavy smokers, we detected Nrf2 and HO-1 cytoplasmic localization. Moreover, we found high oxidative stress, as detected by 4-hydroxynonenal (4-HNE) (immunoblotting), inflammation by IL-8 and IL-6 levels by ELISA, and apoptosis by terminal deoxynucleotidyl transferase dUTP nick end labeling (TUNEL) assay in ATII cells obtained from heavy smokers. Furthermore, we detected early DJ-1 and late Nrf2 expression after ATII cell treatment with CS extract. We also overexpressed DJ-1 by adenovirus construct and found that this restored Nrf2 and HO-1 expression and induced nuclear translocation in heavy smokers. Moreover, DJ-1 overexpression also decreased ATII cell apoptosis caused by CS extract in vitro. Our results indicate that DJ-1 activates the Nrf2-mediated antioxidant defense system. Furthermore, DJ-1 overexpression can restore the impaired Nrf2 pathway, leading to ATII cell protection in heavy smokers. This suggests a potential therapeutic strategy for targeting DJ-1 in CS-related lung diseases.

  3. Sulforaphane and Other Nutrigenomic Nrf2 Activators: Can the Clinician's Expectation Be Matched by the Reality?

    PubMed Central

    Houghton, Christine A.; Fassett, Robert G.; Coombes, Jeff S.

    2016-01-01

    The recognition that food-derived nonnutrient molecules can modulate gene expression to influence intracellular molecular mechanisms has seen the emergence of the fields of nutrigenomics and nutrigenetics. The aim of this review is to describe the properties of nutrigenomic activators of transcription factor Nrf2 (nuclear factor erythroid 2-related factor 2), comparing the potential for sulforaphane and other phytochemicals to demonstrate clinical efficacy as complementary medicines. Broccoli-derived sulforaphane emerges as a phytochemical with this capability, with oral doses capable of favourably modifying genes associated with chemoprevention. Compared with widely used phytochemical-based supplements like curcumin, silymarin, and resveratrol, sulforaphane more potently activates Nrf2 to induce the expression of a battery of cytoprotective genes. By virtue of its lipophilic nature and low molecular weight, sulforaphane displays significantly higher bioavailability than the polyphenol-based dietary supplements that also activate Nrf2. Nrf2 activation induces cytoprotective genes such as those playing key roles in cellular defense mechanisms including redox status and detoxification. Both its high bioavailability and significant Nrf2 inducer capacity contribute to the therapeutic potential of sulforaphane-yielding supplements. PMID:26881038

  4. Knockdown of Nrf2 Inhibits the Angiogenesis of Rat Cardiac Micro-vascular Endothelial Cells under Hypoxic Conditions

    PubMed Central

    Kuang, Lihong; Feng, Jian; He, Guoxiang; Jing, Tao

    2013-01-01

    Angiogenesis plays an important role in myocardial repair after myocardial infarction (MI). Cardiac micro-vascular endothelial cells (CMECs) are important participants in myocardial angiogenesis processes. Recent studies have revealed that Nuclear factor-erythroid 2-related factor 2 (Nrf2), a master transcription factor of endogenous anti-oxidative defense systems, exerts cardio-protection in the cardiovascular system. However, the role of Nrf2 in the process of myocardial angiogenesis and corresponding mechanisms are not fully understood. Thus, the present study investigated the role of Nrf2 in the angiogenesis of rat CMECs to hypoxia. Trans-well assay, three-dimensional Matrigel assay were used to determine cell migration and vascular tube formation. Real-time RT-PCR, ELISA and Western blot were measured mRNA and protein expression. Here, we report that the mRNA and protein expression of Nrf2 and heme oxygenase-1(HO-1) were temporarily upregulated under hypoxic condition. Furthermore, knock down of Nrf2 significantly suppressed the migration and vascular tube formation of rat CMECs to hypoxia, Nrf2 knockdown also significantly decreased HO-1 and vascular endothelial growth factor (VEGF) expression at 48 h after transfection under hypoxic condition. Finally, transfection of CMECs with the Nrf2 over-expressing lentiviral vector upregulated HO-1 expression with a concomitant increase in cell migration and vascular tube formation induced by hypoxia, and this effect was greatly attenuated in the presence of ZnPP (a HO-1 inhibitor). Taken together, these results suggest that Nrf2 may mediate the angiogenesis of CMECs under hypoxic condition, and HO-1 is involved in regulating the angiogenesis of CMECs through Nrf2. Therefore, Nrf2 is a potent regulator of hypoxia-condition mediated angiogenesis in CMECs, which may provide a therapeutic strategy for myocardial repair after MI. PMID:23904790

  5. Nrf2 and Nrf2-related proteins in development and developmental toxicity: Insights from studies in zebrafish (Danio rerio).

    PubMed

    Hahn, Mark E; Timme-Laragy, Alicia R; Karchner, Sibel I; Stegeman, John J

    2015-11-01

    Oxidative stress is an important mechanism of chemical toxicity, contributing to developmental toxicity and teratogenesis as well as to cardiovascular and neurodegenerative diseases and diabetic embryopathy. Developing animals are especially sensitive to effects of chemicals that disrupt the balance of processes generating reactive species and oxidative stress, and those anti-oxidant defenses that protect against oxidative stress. The expression and inducibility of anti-oxidant defenses through activation of NFE2-related factor 2 (Nrf2) and related proteins is an essential process affecting the susceptibility to oxidants, but the complex interactions of Nrf2 in determining embryonic response to oxidants and oxidative stress are only beginning to be understood. The zebrafish (Danio rerio) is an established model in developmental biology and now also in developmental toxicology and redox signaling. Here we review the regulation of genes involved in protection against oxidative stress in developing vertebrates, with a focus on Nrf2 and related cap'n'collar (CNC)-basic-leucine zipper (bZIP) transcription factors. Vertebrate animals including zebrafish share Nfe2, Nrf1, Nrf2, and Nrf3 as well as a core set of genes that respond to oxidative stress, contributing to the value of zebrafish as a model system with which to investigate the mechanisms involved in regulation of redox signaling and the response to oxidative stress during embryolarval development. Moreover, studies in zebrafish have revealed nrf and keap1 gene duplications that provide an opportunity to dissect multiple functions of vertebrate NRF genes, including multiple sensing mechanisms involved in chemical-specific effects. Copyright © 2015. Published by Elsevier Inc.

  6. Nrf2 and Nrf2-Related Proteins in Development and Developmental Toxicity: Insights from studies in Zebrafish (Danio rerio)

    PubMed Central

    Hahn, Mark E.; Timme-Laragy, Alicia R.; Karchner, Sibel I.; Stegeman, John J.

    2015-01-01

    Oxidative stress is an important mechanism of chemical toxicity, contributing to developmental toxicity and teratogenesis as well as to cardiovascular and neurodegenerative diseases and diabetic embryopathy. Developing animals are especially sensitive to effects of chemicals that disrupt the balance of processes generating reactive species and oxidative stress, and those anti-oxidant defenses that protect against oxidative stress. The expression and inducibility of anti-oxidant defenses through activation of NFE2-related factor 2 (Nrf2) and related proteins is an essential process affecting the susceptibility to oxidants, but the complex interactions of Nrf2 in determining embryonic response to oxidants and oxidative stress are only beginning to be understood. The zebrafish (Danio rerio) is an established model in developmental biology and now also in developmental toxicology and redox signaling. Here we review the regulation of genes involved in protection against oxidative stress in developing vertebrates, with a focus on Nrf2 and related cap’n’collar (CNC)-basic-leucine zipper (bZIP) transcription factors. Vertebrate animals including zebrafish share Nfe2, Nrf1, Nrf2, and Nrf3 as well as a core set of genes that respond to oxidative stress, contributing to the value of zebrafish as a model system with which to investigate the mechanisms involved in regulation of redox signaling and the response to oxidative stress during embryolarval development. Moreover, studies in zebrafish have revealed nrf and keap1 gene duplications that provide an opportunity to dissect multiple functions of vertebrate NRF genes, including multiple sensing mechanisms involved in chemical-specific effects. PMID:26130508

  7. Expression of Nrf2 Promotes Schwann Cell-Mediated Sciatic Nerve Recovery in Diabetic Peripheral Neuropathy.

    PubMed

    Tang, Wei; Chen, Xiangfang; Liu, Haoqi; Lv, Qian; Zou, Junjie; Shi, Yongquan; Liu, Zhimin

    2018-04-26

    High glucose-induced oxidative stress and inflammatory responses play an important role in painful diabetic neuropathy by activating the TLR4/NFκB signal pathway. Schwann cells (SCs) are integral to peripheral nerve biology, contributing to saltatory conduction along axons, nerve and axon development, and axonal regeneration. SCs provide a microenvironment favoring vascular regeneration but their low survival ratio in hyperglycemic conditions suppress the function to promote nerve growth. Nuclear factor erythroid 2-related factor 2 (Nrf2) promotes remyelination after peripheral nerve injury. The aim of this study was to identify the role of Nrf2 in SC-mediated functional recovery after sciatic nerve injury. We compared plasma inflammatory factors in diabetic patients (DN) with/without diabetic peripheral neuropathy (DPN) and assessed whether Nrf2 expression in SCs could repair peripheral nerve injury in a rat model. Nrf2, TLR4/NFκB signal pathway and apoptosis relative protein expression were detected by western blot. Apoptosis and angiogenesis were determined by immunofluorescence and tubule formation assay, respectively. Regenerated nerves were determined by transmission electron microscope. Higher levels of inflammatory factors and VEGF expression were found in DPN patients. Cellular experiments indicate that Nrf2 expression inhibits hyperglycemia-induced apoptosis and promotes angiogenesis by regulating the TLR4/NFκB signal pathway. Animal experiments show that nerve conduction velocity, myelin sheath thickness, and sciatic vasa nervorum are restored with transplantation of SCs overexpressing Nrf2. Taken together, the high survival ratio of SCs in a DPN rat model indicates that overexpression of Nrf2 restores nerve injury. © 2018 The Author(s). Published by S. Karger AG, Basel.

  8. The NRF2 Activation and Antioxidative Response Are Not Impaired Overall during Hyperoxia-Induced Lung Epithelial Cell Death

    PubMed Central

    Potteti, Haranatha R.; Reddy, Narsa M.; Hei, Tom K.; Kalvakolanu, Dhananjaya V.; Reddy, Sekhar P.

    2013-01-01

    Lung epithelial and endothelial cell death caused by pro-oxidant insults is a cardinal feature of acute lung injury/acute respiratory distress syndrome (ALI/ARDS) patients. The NF-E2-related factor 2 (NRF2) activation in response to oxidant exposure is crucial to the induction of several antioxidative and cytoprotective enzymes that mitigate cellular stress. Since prolonged exposure to hyperoxia causes cell death, we hypothesized that chronic hyperoxia impairs NRF2 activation, resulting in cell death. To test this hypothesis, we exposed nonmalignant small airway epithelial cells (AECs) to acute (1–12 h) and chronic (36–48 h) hyperoxia and evaluated cell death, NRF2 nuclear accumulation and target gene expression, and NRF2 recruitment to the endogenous HMOX1 and NQO1 promoters. As expected, hyperoxia gradually induced death in AECs, noticeably and significantly by 36 h; ~60% of cells were dead by 48 h. However, we unexpectedly found increased expression levels of NRF2-regulated antioxidative genes and nuclear NRF2 in AECs exposed to chronic hyperoxia as compared to acute hyperoxia. Chromatin Immunoprecipitation (ChIP) assays revealed an increased recruitment of NRF2 to the endogenous HMOX1 and NQO1 promoters in AECs exposed to acute or chronic hyperoxia. Thus, our findings demonstrate that NRF2 activation and antioxidant gene expression are functional during hyperoxia-induced lung epithelial cell death and that chronic hyperoxia does not impair NRF2 signaling overall. PMID:23738042

  9. Partial contribution of the Keap1–Nrf2 system to cadmium-mediated metallothionein expression in vascular endothelial cells

    DOE Office of Scientific and Technical Information (OSTI.GOV)

    Shinkai, Yasuhiro; Kimura, Tomoki; Itagaki, Ayaka

    Cadmium is an environmental electrophile that modifies protein reactive thiols such as Kelch-like ECH-associated protein 1 (Keap1), a negative regulator of nuclear factor-erythroid 2-related factor 2 (Nrf2). In the present study, we investigated a role of the Keap1–Nrf2 system in cellular response to cadmium in vascular endothelial cells. Exposure of bovine aortic endothelial cells to cadmium resulted in modification of Keap1 and Nrf2 activation, thereby up-regulating not only its typical downstream proteins but also metallothionein-1/2. Experiments with siRNA-mediated knockdown of Nrf2 or Keap1 supported participation of the Keap1–Nrf2 system in the modulation of metallothionein-1/2 expression. Furthermore, chromatin immunoprecipitation assay showedmore » that Nrf2 was recruited to the antioxidant response element of the promoter region of the bovine metallothionein-2 gene in the presence of cadmium. These results suggest that the transcription factor Nrf2 plays, at least in part, a role in the changes in metallothionein expression mediated by exposure to cadmium. - Highlights: • Role of the Keap1–Nrf2 system in cellular response to cadmium was examined. • We used bovine aortic endothelial cells as a model of the vascular endothelium. • Exposure of cells to cadmium resulted in modification of Keap1 and Nrf2 activation. • Keap1–Nrf2 system participated in the modulation of metallothionein-1/2 expression. • Nrf2 was recruited to the antioxidant response element of MT2 promoter region.« less

  10. Fenofibrate activates Nrf2 through p62-dependent Keap1 degradation

    DOE Office of Scientific and Technical Information (OSTI.GOV)

    Park, Jeong Su; Yonsei Biomedical Research Institute, Yonsei University College of Medicine, 50 Yonsei-ro, Seodaemun-gu, Seoul 120-752; Kang, Dong Hoon

    Peroxisome proliferator-activated receptor α (PPARα) activates the β-oxidation of fatty acids in the liver. Fenofibrate is a potent agonist of PPARα and is used in the treatment of hyperlipidemia. Fenofibrate treatment often induces the production of intracellular reactive oxygen species (ROS), leading to cell death. The nuclear factor erythroid 2-related factor 2 (Nrf2)-Kelch-like ECH-associated protein 1 (Keap1) pathway is an essential component of the defense mechanism against oxidative stress. However, the molecular mechanism underlying the regulation of the Nrf2-Keap1 pathway in fenofibrate-induced cell death is not known. In this study, we demonstrated that fenofibrate induces Keap1 degradation and Nrf2 activation.more » This fenofibrate-mediated Keap1 degradation is partly dependent on autophagy. Furthermore, fenofibrate-induced Keap1 degradation followed by Nrf2 activation is mainly mediated by p62, which functions as an adaptor protein in the autophagic pathway. Consistent with these findings, ablation of p62 increased fenofibrate-mediated apoptotic cell death associated with ROS accumulation. These results strongly suggest that p62 plays a crucial role in preventing fenofibrate-induced cell death. - Highlights: • Fenofibrate induces cell death by increasing ROS production. • The underlying defense mechanism against this effect is unknown. • Fenofibrate induces autophagy-dependent Keap1 degradation and Nrf2 activation. • This process is p62-dependent; lack of p62 enhanced fenofibrate-mediated apoptosis. • p62 plays a crucial role in preventing fenofibrate-induced cell death.« less

  11. Curcumin plays neuroprotective roles against traumatic brain injury partly via Nrf2 signaling.

    PubMed

    Dong, Wenwen; Yang, Bei; Wang, Linlin; Li, Bingxuan; Guo, Xiangshen; Zhang, Miao; Jiang, Zhenfei; Fu, Jingqi; Pi, Jingbo; Guan, Dawei; Zhao, Rui

    2018-05-01

    Traumatic brain injury (TBI), which leads to high mortality and morbidity, is a prominent public health problem worldwide with no effective treatment. Curcumin has been shown to be beneficial for neuroprotection in vivo and in vitro, but the underlying mechanism remains unclear. This study determined whether the neuroprotective role of curcumin in mouse TBI is dependent on the NF-E2-related factor (Nrf2) pathway. The Feeney weight-drop contusion model was used to mimic TBI. Curcumin was administered intraperitoneally 15 min after TBI induction, and brains were collected at 24 h after TBI. The levels of Nrf2 and its downstream genes (Hmox-1, Nqo1, Gclm, and Gclc) were detected by Western blot and qRT-PCR at 24 h after TBI. In addition, edema, oxidative damage, cell apoptosis and inflammatory reactions were evaluated in wild type (WT) and Nrf2-knockout (Nrf2-KO) mice to explore the role of Nrf2 signaling after curcumin treatment. In wild type mice, curcumin treatment resulted in reduced ipsilateral cortex injury, neutrophil infiltration, and microglia activation, improving neuron survival against TBI-induced apoptosis and degeneration. These effects were accompanied by increased expression and nuclear translocation of Nrf2, and enhanced expression of antioxidant enzymes. However, Nrf2 deletion attenuated the neuroprotective effects of curcumin in Nrf2-KO mice after TBI. These findings demonstrated that curcumin effects on TBI are associated with the activation the Nrf2 pathway, providing novel insights into the neuroprotective role of Nrf2 and the potential therapeutic use of curcumin for TBI. Copyright © 2018. Published by Elsevier Inc.

  12. Enhanced sensitivity of A549 cells to the cytotoxic action of anticancer drugs via suppression of Nrf2 by procyanidins from Cinnamomi Cortex extract

    DOE Office of Scientific and Technical Information (OSTI.GOV)

    Ohnuma, Tomokazu; Matsumoto, Takashi; Itoi, Ayano

    Highlights: {yields} We found a novel inhibitor of Nrf2 known as a chemoresistance factor. {yields} Overexpressed Nrf2 in lung cancer cells was suppressed by Cinnamomi Cortex extract. {yields} Cytotoxic action of anticancer drugs in cells treated with the extract was enhanced. {yields} Procyanidin tetramers and pentamers were active components in suppressing Nrf2. -- Abstract: Nuclear factor-E2-related factor 2 (Nrf2) is an important cytoprotective transcription factor because Nrf2-regulated enzymes play a key role in antioxidant and detoxification processes. Recent studies have reported that lung cancer cells overexpressing Nrf2 exhibit increased resistance to chemotherapy. Suppression of overexpressed Nrf2 is needed for amore » new therapeutic approach against lung cancers. In the present study, we found that Cinnamomi Cortex extract (CCE) has an ability to suppress Nrf2-regulated enzyme activity and Nrf2 expression in human lung cancer A549 cells with high Nrf2 activity. Moreover, we demonstrated that CCE significantly enhances sensitivity of A549 cells to the cytotoxic action of doxorubicin and etoposide as well as increasing the intracellular accumulation of both drugs. These results suggest that CCE might be an effective concomitant agent to reduce anticancer drug resistance derived from Nrf2 overexpression. Bioactivity-guided fractionation revealed that procyanidin tetramers and pentamers contained in CCE were active components in suppressing Nrf2.« less

  13. Synthesis, evaluation, and metabolism of novel [6]-shogaol derivatives as potent Nrf2 activators.

    PubMed

    Zhu, Yingdong; Wang, Pei; Zhao, Yantao; Yang, Chun; Clark, Anderson; Leung, TinChung; Chen, Xiaoxin; Sang, Shengmin

    2016-06-01

    Oxidative stress is a central component of many chronic diseases. The Kelch-like ECH-associated protein 1 (Keap1)-nuclear factor erythroid 2 p45-related factor 2 (Nrf2) system is a major regulatory pathway of cytoprotective genes against oxidative and electrophilic stress. Activation of the Nrf2 pathway plays crucial roles in the chemopreventive effects of various inducers. In this study, we developed a novel class of potent Nrf2 activators derived from ginger compound, [6]-shogaol (6S), using the Tg[glutathione S-transferase pi 1 (gstp1):green fluorescent protein (GFP)] transgenic zebrafish model. Investigation of structure-activity relationships of 6S derivatives indicates that the combination of an α,β-unsaturated carbonyl entity and a catechol moiety in one compound enhances the Tg(gstp1:GFP) fluorescence signal in zebrafish embryos. Chemical reaction and in vivo metabolism studies of the four most potent 6S derivatives showed that both α,β-unsaturated carbonyl entity and catechol moiety act as major active groups for conjugation with the sulfhydryl groups of the cysteine residues. In addition, we further demonstrated that 6S derivatives increased the expression of Nrf2 downstream target, heme oxygenase-1, in both a dose- and time-dependent manner. These results suggest that α,β-unsaturated carbonyl entity and catechol moiety of 6S derivatives may react with the cysteine residues of Keap1, disrupting the Keap1-Nrf2 complex, thereby liberating and activating Nrf2. Our findings of natural product-derived Nrf2 activators lead to design options of potent Nrf2 activators for further optimization. Copyright © 2016 Elsevier Inc. All rights reserved.

  14. Role of Nrf2/HO-1 system in development, oxidative stress response and diseases: an evolutionarily conserved mechanism.

    PubMed

    Loboda, Agnieszka; Damulewicz, Milena; Pyza, Elzbieta; Jozkowicz, Alicja; Dulak, Jozef

    2016-09-01

    The multifunctional regulator nuclear factor erythroid 2-related factor (Nrf2) is considered not only as a cytoprotective factor regulating the expression of genes coding for anti-oxidant, anti-inflammatory and detoxifying proteins, but it is also a powerful modulator of species longevity. The vertebrate Nrf2 belongs to Cap 'n' Collar (Cnc) bZIP family of transcription factors and shares a high homology with SKN-1 from Caenorhabditis elegans or CncC found in Drosophila melanogaster. The major characteristics of Nrf2 are to some extent mimicked by Nrf2-dependent genes and their proteins including heme oxygenase-1 (HO-1), which besides removing toxic heme, produces biliverdin, iron ions and carbon monoxide. HO-1 and their products exert beneficial effects through the protection against oxidative injury, regulation of apoptosis, modulation of inflammation as well as contribution to angiogenesis. On the other hand, the disturbances in the proper HO-1 level are associated with the pathogenesis of some age-dependent disorders, including neurodegeneration, cancer or macular degeneration. This review summarizes our knowledge about Nrf2 and HO-1 across different phyla suggesting their conservative role as stress-protective and anti-aging factors.

  15. Quercetin attenuates toosendanin-induced hepatotoxicity through inducing the Nrf2/GCL/GSH antioxidant signaling pathway.

    PubMed

    Jin, Yao; Huang, Zhen-Lin; Li, Li; Yang, Yang; Wang, Chang-Hong; Wang, Zheng-Tao; Ji, Li-Li

    2018-06-19

    Toosendanin (TSN) is the main active compound in Toosendan Fructus and Meliae Cortex, two commonly used traditional Chinese medicines. TSN has been reported to induce hepatotoxicity, but its mechanism remains unclear. In this study, we demonstrated the critical role of nuclear factor erythroid 2-related factor 2 (Nrf2) in protecting against TSN-induced hepatotoxicity in mice and human normal liver L-02 cells. In mice, administration of TSN (10 mg/kg)-induced acute liver injury evidenced by increased serum alanine/aspartate aminotransferase (ALT/AST) and alkaline phosphatase (ALP) activities, and total bilirubin (TBiL) content as well as the histological changes. Furthermore, TSN markedly increased liver reactive oxygen species (ROS) and malondialdehyde (MDA) levels, and decreased liver glutathione (GSH) content and Nrf2 expression. In L-02 cells, TSN (2 μM) time-dependently reduced glutamate-cysteine ligase (GCL) activity and cellular expression of the catalytic/modify subunit of GCL (GCLC/GCLM). Moreover, TSN reduced cellular GSH content and the increased ROS formation, and time-dependently decreased Nrf2 expression and increased the expression of the Nrf2 inhibitor protein kelch-like ECH-associated protein-1 (Keap1). Pre-administration of quercetin (40, 80 mg/kg) effectively inhibited TSN-induced liver oxidative injury and reversed the decreased expression of Nrf2 and GCLC/GCLM in vivo and in vitro. In addition, the quercetin-provided protection against TSN-induced hepatotoxicity was diminished in Nrf2 knock-out mice. In conclusion, TSN decreases cellular GSH content by reducing Nrf2-mediated GCLC/GCLM expression via decreasing Nrf2 expression. Quercetin attenuates TSN-induced hepatotoxicity by inducing the Nrf2/GCL/GSH antioxidant signaling pathway. This study implies that inducing Nrf2 activation may be an effective strategy to prevent TSN-induced hepatotoxicity.

  16. Oncogenic mutations in KEAP1 disturbing inhibitory Nrf2-Keap1 interaction: Activation of antioxidative pathway in papillary thyroid carcinoma.

    PubMed

    Danilovic, Debora Lucia Seguro; de Mello, Evandro Sobroza; Frazzato, Eliana Salgado Turri; Wakamatsu, Alda; de Lima Jorge, Alexander Augusto; Hoff, Ana Oliveira; Marui, Suemi

    2018-06-01

    Nuclear factor erythroid 2-like 2 (NFE2L2) encodes Nrf2, transcription factor of antioxidative genes. In the presence of reactive oxygen species, Keap1 (Kelch-ECH-associating protein-1) inhibitor complex undergoes conformational changes disrupting Keap1-Nrf2 binding and Nrf2 translocates into nucleus. We evaluated the presence of mutations in NFE2L2 and KEAP1 in papillary thyroid carcinomas (PTCs) and correlated them with clinical presentation. Coding regions of NFE2L2 and KEAP1 were sequenced in 131 patients with PTC. Clinical and histopathological features were analyzed. Immunohistochemical analysis of Nrf2 expression was performed in mutated carcinomas. Although no mutations were found in NFE2L2, missense mutations in KEAP1 were observed in 6 patients with PTC (4.6%). Immunohistochemistry showed increased Nrf2 expression in nuclei of all mutated carcinomas, which presented poor prognostic features in histopathology. We identified mutations in KEAP1 associated with Nrf2 overexpression in PTC. Mutations favored disruption of inhibitory interaction Nrf2-Keap1 to enable increased antioxidant Nrf2 activity, possibly with prognostic consequences. © 2018 Wiley Periodicals, Inc.

  17. An essential role of Nrf2 in American ginseng-mediated anti-oxidative actions in cardiomyocytes.

    PubMed

    Li, Jinqing; Ichikawa, Tomonaga; Jin, Yu; Hofseth, Lorne J; Nagarkatti, Prakash; Nagarkatti, Mitzi; Windust, Anthony; Cui, Taixing

    2010-07-20

    Ginseng has been used as a folk medicine for thousands of years in Asia, and has become a popular herbal medicine world-wide. Recent studies have revealed that ginseng, including American ginseng, exerts antioxidant effects in the cardiovascular system; however, the underlying mechanisms are not fully understood. Thus, we investigated role of Nrf2, a master transcription factor of endogenous anti-oxidative defense systems, in the regulation of American ginseng-mediated anti-oxidative actions in cardiomyocytes. A standardized crude extract of American ginseng was supplied by the National Research Council of Canada, Institute for National Measurement Standards. H9C2 cells, a rat cardiomyocyte cell line, were exposed to angiotensin II (Ang II) or tumor necrosis factor alpha (TNFalpha) to induce oxidative stress that was examined by measuring formation of reactive oxygen and nitrogen species. Oxidative stress-induced cell death was induced by exogenous addition of hydrogen peroxide (H(2)O(2)). Proteins were measured by Western blot and mRNA expression was determined by quantitative real time PCR. Nrf2-driven transcriptional activity was assessed by antioxidant response element (ARE)-luciferase reporter assay. Direct Nrf2 binding to its target gene promoters was determined by chromatin immunoprecipitation assay. Adenoviral over-expression of Nrf2 shRNA was utilized to knock down Nrf2 in H9C2 cells. Immunochemical staining was applied for Nrf2 expression in the heart. American ginseng induced dramatic increases in Nrf2 protein expression, Nrf2 nuclear translocation, Nrf2 transcriptional activity, direct Nrf2 binding to its target gene promoters, and expression of a group of anti-oxidative genes driven by Nrf2 in H9C2 cells. In addition, American ginseng inhibited Ang II- or TNFalpha-induced free radical formation and H(2)O(2)-induced cell death in H9C2 cells over-expressed with control shRNA but not in the cells over-expressed with Nrf2 shRNA. Finally, oral

  18. Nrf2 Deficiency in Dendritic Cells Enhances the Adjuvant Effect of Ambient Ultrafine Particles on Allergic Sensitization

    EPA Science Inventory

    Airborne particulate matter (PM) is an important risk factor for asthma. Generation of oxidative stress by PM-associated chemicals is a major mechanism of its health effects. Transcription factor nuclear factor (erythroid-derived 2)-like 2 (Nrf2) mediates antioxidant and phase II...

  19. High Nrf2 expression in alveolar type I pneumocytes is associated with low recurrences in primary spontaneous pneumothorax.

    PubMed

    Chen, Yu-Wen; Chiu, Wen-Chin; Chou, Shah-Hwa; Su, Yu-Han; Huang, Ying-Fong; Lee, Yen-Lung; Yuan, Shyng-Shiou F; Lee, Yi-Chen

    2017-10-01

    Recurrent primary spontaneous pneumothorax (PSP) is a troublesome problem and a major concern for the patients. This study examined whether nuclear factor erythroid 2-related factor 2 (Nrf2) expression in alveolar type I pneumocytes was associated with the clinical manifestations of PSP patients including disease recurrence. Eighty-eight PSP patients who were managed with needlescopic video-assisted thoracoscopic surgery (NVATS) were included in this study. Immunohistochemistry (IHC) was assessed to determine Nrf2 expression in resected lung tissues and the results were correlated with clinicopathological characteristics by the chi-square or the Fisher's exact test. The prognostic value of Nrf2 for overall recurrence was evaluated by univariate and multivariable Cox regression model. The expression of Nrf2 was observed in type I pneumocytes of lung tissues from PSP patients by IHC. We found that low Nrf2 expression in PSP patients, especially in young (age ≤ 20, p = 0.033) and body mass index (BMI) ≥18 kg/m 2 (p = 0.019) groups, was significantly correlated with PSP recurrence. In the univariate and multivariate analyses, high Nrf2 expression was a significant protective factor for overall recurrence in PSP patients (univariate: p = 0.026; multivariate: p = 0.004). The expression level of Nrf2 in alveolar type I pneumocytes was a potential factor involved in PSP recurrence. Our findings suggest that elevated Nrf2 expression in PSP patients may be a promising way for reducing PSP recurrence. Copyright © 2017. Published by Elsevier Taiwan.

  20. The aryl hydrocarbon receptor and estrogen receptor alpha differentially modulate nuclear factor erythroid-2-related factor 2 transactivation in MCF-7 breast cancer cells

    DOE Office of Scientific and Technical Information (OSTI.GOV)

    Lo, Raymond; Matthews, Jason, E-mail: jason.matthews@utoronto.ca

    2013-07-15

    Nuclear factor erythroid-2-related factor 2 (NRF2; NFE2L2) plays an important role in mediating cellular protection against reactive oxygen species. NRF2 signaling is positively modulated by the aryl hydrocarbon receptor (AHR) but inhibited by estrogen receptor alpha (ERα). In this study we investigated the crosstalk among NRF2, AHR and ERα in MCF-7 breast cancer cells treated with the NRF2 activator sulforaphane (SFN), a dual AHR and ERα activator, 3,3′-diindolylmethane (DIM), 2,3,7,8-tetrachlorodibenzo-p-dioxin (TCDD) or 17β-estradiol (E2). SFN-dependent increases in NADPH-dependent oxidoreductase 1 (NQO1) and heme oxygenase I (HMOX1) mRNA levels were significantly reduced after co-treatment with E2. E2-dependent repression of NQO1 andmore » HMOX1 was associated with increased ERα but reduced p300 recruitment and reduced histone H3 acetylation at both genes. In contrast, DIM + SFN or TCDD + SFN induced NQO1 and HMOX1 mRNA expression to levels higher than SFN alone, which was prevented by RNAi-mediated knockdown of AHR. DIM + SFN but not TCDD + SFN also induced recruitment of ERα to NQO1 and HMOX1. However, the presence of AHR at NQO1 and HMOX1 restored p300 recruitment and histone H3 acetylation, thereby reversing the ERα-dependent repression of NRF2. Taken together, our study provides further evidence of functional interplay among NRF2, AHR and ERα signaling pathways through altered p300 recruitment to NRF2-regulated target genes. - Highlights: • We examined crosstalk among ERα, AHR, and NRF2 in MCF-7 breast cancer cells. • AHR enhanced the mRNA expression levels of two NRF2 target genes – HMOX1 and NQO1. • ERα repressed HMOX1 and NQO1 expression via decreased histone acetylation. • AHR prevented ERα-dependent repression of HMOX1 and NQO1.« less

  1. Nrf2-Dependent and -Independent Effects of tert-Butylhydroquinone, CDDO-Im, and H2O2 in Human Jurkat T Cells as Determined by CRISPR/Cas9 Gene Editing.

    PubMed

    Zagorski, Joseph W; Maser, Tyler P; Liby, Karen T; Rockwell, Cheryl E

    2017-05-01

    Nuclear factor erythroid 2-related factor 2 (Nrf2) is a stress-activated transcription factor activated by stimuli such as electrophilic compounds and other reactive xenobiotics. Previously, we have shown that the commonly used food additive and Nrf2 activator tert -butylhydroquinone (tBHQ) suppresses interleukin-2 (IL-2) production, CD25 expression, and NF κ B activity in human Jurkat T cells. The purpose of the current studies was to determine whether these effects were dependent upon Nrf2 by developing a human Nrf2-null T cell model using clustered regularly interspaced short palindromic repeats (CRISPR)/CRISPR-associated protein 9 technology. The current studies show that suppression of CD25 expression by tBHQ is partially dependent on Nrf2, whereas inhibition of IL-2 secretion is largely Nrf2-independent. Interestingly, tBHQ inhibited NF κ B activation in an Nrf2-independent manner. This was an unexpected finding since Nrf2 inhibits NF κ B activation in other models. These results led us to investigate another more potent Nrf2 activator, the synthetic triterpenoid 1[2-cyano-3,12-dioxooleana-1,9(11)-dien-28-oyl]imidazole (CDDO-Im). Treatment of wild-type and Nrf2-null Jurkat T cells with CDDO-Im resulted in an Nrf2-dependent suppression of IL-2. Furthermore, susceptibility to reactive oxygen species was significantly enhanced in the Nrf2-null clones as determined by decreased mitochondrial membrane potential and cell viability. Importantly, this study is the first to describe the generation of a human Nrf2-null model, which is likely to have multiple applications in immunology and cancer biology. Collectively, this study demonstrates a role for Nrf2 in the effects of CDDO-Im on CD25 and IL-2 expression, whereas the effect of tBHQ on these parameters is complex and likely involves modulation of multiple stress-activated transcription factors, including NF κ B and Nrf2. Copyright © 2017 by The American Society for Pharmacology and Experimental Therapeutics.

  2. Nrf2 mediates redox adaptation in NOX4-overexpressed non-small cell lung cancer cells

    DOE Office of Scientific and Technical Information (OSTI.GOV)

    Wu, Qipeng; Yao, Bei; Li, Ning

    The redox adaptation mechanisms in cancer cells are very complex and remain largely unclear. Our previous studies have confirmed that NADPH oxidase 4 (NOX4) is abundantly expressed in non-small cell lung cancer (NSCLC) and confers apoptosis resistance on NSCLC cells. However, the comprehensive mechanisms for NOX4-mediated oxidative resistance of cancer cells remain still undentified. The present study found that NOX4-derived H{sub 2}O{sub 2} enhanced the nuclear factor erythroid 2-related factor 2 (Nrf2) stability via disruption of redox-dependent proteasomal degradation and stimulated its activity through activation of PI3K signaling. Specifically, the results showed that ectopic NOX4 expression did not induce apoptosismore » of A549 cells; however, inhibition of Nrf2 resulted in obvious apoptotic death of NOX4-overexpressed A549 cells, accompanied by a significant increase in H{sub 2}O{sub 2} level and decrease in GSH content. Besides, inhibition of Nrf2 could suppress cell growth and efficiently reverse the enhancement effect of NOX4 on cell growth. The in vivo data confirmed that inhibition of Nrf2 could interfere apoptosis resistance in NOX4-overexpressed A549 tumors and led to cell growth inhibition. In conclusion, these results reveal that Nrf2 is critically involved in redox adaptation regulation in NOX4-overexpressed NSCLC cells. Therefore, NOX4 and Nrf2 may be promising combination targets against malignant progression of NSCLC. - Highlights: • NOX4-derived H{sub 2}O{sub 2} upregulates Nrf2 expression and activity in NSCLC. • Nrf2 confers apoptosis resistance in NOX4-overexpressed NSCLC cells. • Inhibition of Nrf2 reverses the enhancement effect of NOX4 on cell growth.« less

  3. Synthetic Lignan Secoisolariciresinol Diglucoside (LGM2605) Reduces Asbestos-Induced Cytotoxicity in an Nrf2-Dependent and -Independent Manner.

    PubMed

    Pietrofesa, Ralph A; Chatterjee, Shampa; Park, Kyewon; Arguiri, Evguenia; Albelda, Steven M; Christofidou-Solomidou, Melpo

    2018-03-02

    Asbestos exposure triggers inflammatory processes associated with oxidative stress and tissue damage linked to malignancy. LGM2605 is the synthetic lignan secoisolariciresinol diglucoside (SDG) with free radical scavenging, antioxidant, and anti-inflammatory properties in diverse inflammatory cell and mouse models, including exposure to asbestos fibers. Nuclear factor-E2 related factor 2 (Nrf2) activation and boosting of endogenous tissue defenses were associated with the protective action of LGM2605 from asbestos-induced cellular damage. To elucidate the role of Nrf2 induction by LGM2605 in protection from asbestos-induced cellular damage, we evaluated LGM2605 in asbestos-exposed macrophages from wild-type (WT) and Nrf2 disrupted (Nrf2 - / - ) mice. Cells were pretreated with LGM2605 (50 µM and 100 µM) and exposed to asbestos fibers (20 µg/cm²) and evaluated 8 h and 24 h later for inflammasome activation, secreted cytokine levels (interleukin-1β (IL-1β), interleukin-18 (IL-18), interleukin-6 (IL-6), and tumor necrosis factor alpha (TNFα)), cytotoxicity and cell death, nitrosative stress, and Nrf2-regulated enzyme levels. Asbestos exposure induced robust oxidative and nitrosative stress, cell death and cytotoxicity, which were equally mitigated by LGM2605. Inflammasome activation was significantly attenuated in Nrf2 -/- macrophages compared to WT, and the protective action of LGM2605 was seen only in WT cells. In conclusion, in a cell model of asbestos-induced toxicity, LGM2605 acts via protective mechanisms that may not involve Nrf2 activation.

  4. The Keap1/Nrf2 pathway in health and disease: from the bench to the clinic.

    PubMed

    O'Connell, Maria A; Hayes, John D

    2015-08-01

    The transcription factor nuclear factor-erythroid 2 p45-related factor 2 (Nrf2, with gene called NFE2L2) is a master regulator of the antioxidant response. In the last decade, interest has intensified in this research area as its importance in several physiological and pathological processes has become widely recognized; these include redox signalling and redox homoeostasis, drug metabolism and disposition, intermediary metabolism, cellular adaptation to stress, chemoprevention and chemoresistance, toxicity, inflammation, neurodegeneration, lipogenesis and aging. Regulation of Nrf2 is complex and although much attention has focussed on its repression by Kelch-like ECH-associated protein-1 (Keap1), recently it has become increasingly apparent that it is also controlled by cross-talk with other signalling pathways including the glycogen synthase kinase-3 (GSK-3)-β-transducin repeat-containing protein (β-TrCP) axis, ERAD (endoplasmic reticulum-associated degradation)-associated E3 ubiquitin-protein ligase (Hrd1, also called synoviolin), nuclear factor-kappa B (NF-κB), Notch and AMP kinase. Due to its beneficial role in several diseases, Nrf2 has become a major therapeutic target, with novel natural, synthetic and targeted small molecules currently under investigation to modulate the pathway and in clinical trials. © 2015 Authors; published by Portland Press Limited.

  5. NRF2: Translating the Redox Code

    PubMed Central

    Tummala, Krishna S.; Kottakis, Filippos; Bardeesy, Nabeel

    2016-01-01

    Cancer requires mechanisms to mitigate reactive oxygen species (ROS) generated during rapid growth, such as induction of the antioxidant transcription factor, Nrf2. However, the targets of ROS-mediated cytotoxicity are unclear. Recent studies in pancreatic cancer show that redox control by Nrf2 prevents cysteine oxidation of the mRNA translational machinery, thereby supporting efficient protein synthesis. PMID:27555347

  6. Expression of the Nrf2 and Keap1 proteins and their clinical significance in osteosarcoma

    DOE Office of Scientific and Technical Information (OSTI.GOV)

    Zhang, Jihong, E-mail: zhangjihong63@163.com; Wang, Xiaojuan, E-mail: yangjian142@163.com; Wu, Wuzhou, E-mail: jiangchunli68@163.com

    Objective: To investigate the expression and clinical significance of nuclear factor (erythroid-derived 2)-like 2 (Nrf2) and Kelch-like ECH-associated protein 1 (Keap1) in osteosarcoma tissue. Methods: The data of 102 osteosarcoma patients who underwent surgical treatment at our hospital from June 2000 to March 2009 were collected. The expression levels of the Nrf2 and Keap1 proteins in osteosarcoma tissue and normal peritumour tissues were detected by immunohistochemistry, and the relationship between the expression level and the clinical and pathological features as well as the prognosis was explored. Results: The nuclear expression rate of Nrf2 was 77.5% in osteosarcoma tissue, which wasmore » significantly higher than the rate in normal peritumour bone tissue (9.8%) (P < 0.05). The expression rate of the Keap1 protein in osteosarcoma tissue was 13.7%, which was significantly lower than the rate in normal peritumour tissue (80.4%). In addition, Nrf2/Keap1 expression was unrelated to patient gender and age, tumour site, and histological type and was related to metastasis and patient response to chemotherapy (P < 0.05). The five-year survival rate was significantly lower in patients with positive Nrf2 expression than in those with negative Nrf2 expression (p = 0.023), and it was significantly higher in patients with positive Keap1 expression than in those with negative Keap1 expression (P = 0.018). Conclusion: The expression of Nrf2-Keap1 is abnormal in osteosarcoma tissue and shows significant clinical relevance for determining the prognosis of osteosarcoma.« less

  7. DJ-1 Modulates Nuclear Erythroid 2–Related Factor-2–Mediated Protection in Human Primary Alveolar Type II Cells in Smokers

    PubMed Central

    Bahmed, Karim; Messier, Elise M.; Zhou, Wenbo; Tuder, Rubin M.; Freed, Curt R.; Chu, Hong Wei; Kelsen, Steven G.; Bowler, Russell P.; Mason, Robert J.

    2016-01-01

    Cigarette smoke (CS) is a main source of oxidative stress and a key risk factor for emphysema, which consists of alveolar wall destruction. Alveolar type (AT) II cells are in the gas exchange regions of the lung. We isolated primary ATII cells from deidentified organ donors whose lungs were not suitable for transplantation. We analyzed the cell injury obtained from nonsmokers, moderate smokers, and heavy smokers. DJ-1 protects cells from oxidative stress and induces nuclear erythroid 2–related factor-2 (Nrf2) expression, which activates the antioxidant defense system. In ATII cells isolated from moderate smokers, we found DJ-1 expression by RT-PCR, and Nrf2 and heme oxygenase (HO)-1 translocation by Western blotting and immunocytofluorescence. In ATII cells isolated from heavy smokers, we detected Nrf2 and HO-1 cytoplasmic localization. Moreover, we found high oxidative stress, as detected by 4-hydroxynonenal (4-HNE) (immunoblotting), inflammation by IL-8 and IL-6 levels by ELISA, and apoptosis by terminal deoxynucleotidyl transferase dUTP nick end labeling (TUNEL) assay in ATII cells obtained from heavy smokers. Furthermore, we detected early DJ-1 and late Nrf2 expression after ATII cell treatment with CS extract. We also overexpressed DJ-1 by adenovirus construct and found that this restored Nrf2 and HO-1 expression and induced nuclear translocation in heavy smokers. Moreover, DJ-1 overexpression also decreased ATII cell apoptosis caused by CS extract in vitro. Our results indicate that DJ-1 activates the Nrf2-mediated antioxidant defense system. Furthermore, DJ-1 overexpression can restore the impaired Nrf2 pathway, leading to ATII cell protection in heavy smokers. This suggests a potential therapeutic strategy for targeting DJ-1 in CS-related lung diseases. PMID:27093578

  8. Distinct Nrf2 Signaling Mechanisms of Fumaric Acid Esters and Their Role in Neuroprotection against 1-Methyl-4-Phenyl-1,2,3,6-Tetrahydropyridine-Induced Experimental Parkinson's-Like Disease.

    PubMed

    Ahuja, Manuj; Ammal Kaidery, Navneet; Yang, Lichuan; Calingasan, Noel; Smirnova, Natalya; Gaisin, Arsen; Gaisina, Irina N; Gazaryan, Irina; Hushpulian, Dmitry M; Kaddour-Djebbar, Ismail; Bollag, Wendy B; Morgan, John C; Ratan, Rajiv R; Starkov, Anatoly A; Beal, M Flint; Thomas, Bobby

    2016-06-08

    A promising approach to neurotherapeutics involves activating the nuclear-factor-E2-related factor 2 (Nrf2)/antioxidant response element signaling, which regulates expression of antioxidant, anti-inflammatory, and cytoprotective genes. Tecfidera, a putative Nrf2 activator, is an oral formulation of dimethylfumarate (DMF) used to treat multiple sclerosis. We compared the effects of DMF and its bioactive metabolite monomethylfumarate (MMF) on Nrf2 signaling and their ability to block 1-methyl-4-phenyl-1,2,3,6-tetrahydropyridine (MPTP)-induced experimental Parkinson's disease (PD). We show that in vitro DMF and MMF activate the Nrf2 pathway via S-alkylation of the Nrf2 inhibitor Keap1 and by causing nuclear exit of the Nrf2 repressor Bach1. Nrf2 activation by DMF but not MMF was associated with depletion of glutathione, decreased cell viability, and inhibition of mitochondrial oxygen consumption and glycolysis rates in a dose-dependent manner, whereas MMF increased these activities in vitro However, both DMF and MMF upregulated mitochondrial biogenesis in vitro in an Nrf2-dependent manner. Despite the in vitro differences, both DMF and MMF exerted similar neuroprotective effects and blocked MPTP neurotoxicity in wild-type but not in Nrf2 null mice. Our data suggest that DMF and MMF exhibit neuroprotective effects against MPTP neurotoxicity because of their distinct Nrf2-mediated antioxidant, anti-inflammatory, and mitochondrial functional/biogenetic effects, but MMF does so without depleting glutathione and inhibiting mitochondrial and glycolytic functions. Given that oxidative damage, neuroinflammation, and mitochondrial dysfunction are all implicated in PD pathogenesis, our results provide preclinical evidence for the development of MMF rather than DMF as a novel PD therapeutic. Almost two centuries since its first description by James Parkinson, Parkinson's disease (PD) remains an incurable disease with limited symptomatic treatment. The current study provides

  9. Selenitetriglicerydes affect CYP1A1 and QR activity by involvement of reactive oxygen species and Nrf2 transcription factor.

    PubMed

    Suchocki, Piotr; Misiewicz-Krzemińska, Irena; Skupińska, Katarzyna; Niedźwiecka, Katarzyna; Lubelska, Katarzyna; Fijałek, Zbigniew; Kasprzycka-Guttman, Teresa

    2010-01-01

    Selenitetriglycerides are a group of compounds that contain selenium (Se) (IV). In this paper, we present the results of examinations of three structurally-related selenitetriglicerydes that contain various Se concentrations: 2%, 5% and 7% Selol. The present study concentrates on the effect of Selol on phase 1 and 2 enzyme activity and the implications of free radicals and the nuclear erythroid 2-related factor 2 (Nrf2)-antioxidant response element (ARE) pathway in the activity of this compound. The cytotoxic and cytostatic activities of the three kinds of Selol were evaluated; however, the cytotoxic effect was observed only for 7% Selol. Our results show that 2% Selol acts as a monofunctional inducer of phase 2 enzyme activity, and the induction is mediated by the Nrf2 transcription factor. Selol 7% acts in an opposite manner and induces phase 1 with simultaneous inhibition of phase 2 enzyme activity. The differential effect can be associated with the increase in Se content, leading to a change in the structure of the compound.

  10. Impact of Nrf2 on UVB-induced skin inflammation/photoprotection and photoprotective effect of sulforaphane.

    PubMed

    Saw, Constance L; Huang, Mou-Tuan; Liu, Yue; Khor, Tin Oo; Conney, Allan H; Kong, Ah-Ng

    2011-06-01

    Ultraviolet (UV) of sunlight is a complete carcinogen that can burn skin, enhance inflammation, and drive skin carcinogenesis. Previously, we have shown that sulforaphane (SFN) inhibited chemically induced skin carcinogenesis via nuclear factor (erythroid-derived 2)-like 2 (Nrf2) and others have shown that broccoli sprout extracts containing high SFN protected against UV-induced skin carcinogenesis in SKH-1 hairless mice. A recent study showed that there was no difference between Nrf2 knockout (Nrf2 KO) and Nrf2 wild-type (WT) BALB/C mice after exposing to high dose of UVB. Since Nrf2 plays critical roles in the anti-oxidative stress/anti-inflammatory responses, it is relevant to assess the role of Nrf2 for photoprotection against UV. In this context, the role of Nrf2 in UVB-induced skin inflammation in Nrf2 WT and Nrf2 KO C57BL/6 mice was studied. A single dose of UVB (300 mJ/cm(2)) resulted in skin inflammation in both WT and Nrf2 KO (-/-) mice (KO mice) at 8 h and 8 d following UVB irradiation. In the WT mice inflammation returned to the basal level to a greater extent when compared to the KO mice. SFN treatment of Nrf2 WT but not Nrf2 KO mice restored the number of sunburn cells back to their basal level by 8 d after UVB irradiation. Additionally, UVB-induced short-term inflammatory biomarkers (interleukin-1β and interleukin-6) were increased in the KO mice and UVB-induced apoptotic cells in the KO mice were significantly higher as compared to that in the WT. Taken together, our results show that functional Nrf2 confers a protective effect against UVB-induced inflammation, sunburn reaction, and SFN-mediated photoprotective effects in the skin. Copyright © 2010 Wiley-Liss, Inc.

  11. Sulforaphane Attenuation of Type 2 Diabetes-Induced Aortic Damage Was Associated with the Upregulation of Nrf2 Expression and Function

    PubMed Central

    Wang, Yonggang; Zhang, Zhiguo; Sun, Wanqing; Tan, Yi; Liu, Yucheng; Zheng, Yang; Liu, Quan; Cai, Lu; Sun, Jian

    2014-01-01

    Type 2 diabetes mellitus (T2DM) significantly increases risk for vascular complications. Diabetes-induced aorta pathological changes are predominantly attributed to oxidative stress. Nuclear factor E2-related factor-2 (Nrf2) is a transcription factor orchestrating antioxidant and cytoprotective responses to oxidative stress. Sulforaphane protects against oxidative damage by increasing Nrf2 expression and its downstream target genes. Here we explored the protective effect of sulforaphane on T2DM-induced aortic pathogenic changes in C57BL/6J mice which were fed with high-fat diet for 3 months, followed by a treatment with streptozotocin at 100 mg/kg body weight. Diabetic and nondiabetic mice were randomly divided into groups with and without 4-month sulforaphane treatment. Aorta of T2DM mice exhibited significant increases in the wall thickness and structural derangement, along with significant increases in fibrosis (connective tissue growth factor and transforming growth factor), inflammation (tumor necrosis factor-α and vascular cell adhesion molecule 1), oxidative/nitrative stress (3-nitrotyrosine and 4-hydroxy-2-nonenal), apoptosis, and cell proliferation. However, these pathological changes were significantly attenuated by sulforaphane treatment that was associated with a significant upregulation of Nrf2 expression and function. These results suggest that sulforaphane is able to upregulate aortic Nrf2 expression and function and to protect the aorta from T2DM-induced pathological changes. PMID:24707343

  12. Sulforaphane attenuation of type 2 diabetes-induced aortic damage was associated with the upregulation of Nrf2 expression and function.

    PubMed

    Wang, Yonggang; Zhang, Zhiguo; Sun, Wanqing; Tan, Yi; Liu, Yucheng; Zheng, Yang; Liu, Quan; Cai, Lu; Sun, Jian

    2014-01-01

    Type 2 diabetes mellitus (T2DM) significantly increases risk for vascular complications. Diabetes-induced aorta pathological changes are predominantly attributed to oxidative stress. Nuclear factor E2-related factor-2 (Nrf2) is a transcription factor orchestrating antioxidant and cytoprotective responses to oxidative stress. Sulforaphane protects against oxidative damage by increasing Nrf2 expression and its downstream target genes. Here we explored the protective effect of sulforaphane on T2DM-induced aortic pathogenic changes in C57BL/6J mice which were fed with high-fat diet for 3 months, followed by a treatment with streptozotocin at 100 mg/kg body weight. Diabetic and nondiabetic mice were randomly divided into groups with and without 4-month sulforaphane treatment. Aorta of T2DM mice exhibited significant increases in the wall thickness and structural derangement, along with significant increases in fibrosis (connective tissue growth factor and transforming growth factor), inflammation (tumor necrosis factor-α and vascular cell adhesion molecule 1), oxidative/nitrative stress (3-nitrotyrosine and 4-hydroxy-2-nonenal), apoptosis, and cell proliferation. However, these pathological changes were significantly attenuated by sulforaphane treatment that was associated with a significant upregulation of Nrf2 expression and function. These results suggest that sulforaphane is able to upregulate aortic Nrf2 expression and function and to protect the aorta from T2DM-induced pathological changes.

  13. Impaired redox signaling and antioxidant gene expression in endothelial cells in diabetes: a role for mitochondria and the nuclear factor-E2-related factor 2-Kelch-like ECH-associated protein 1 defense pathway.

    PubMed

    Cheng, Xinghua; Siow, Richard C M; Mann, Giovanni E

    2011-02-01

    Type 2 diabetes is an age-related disease associated with vascular pathologies, including severe blindness, renal failure, atherosclerosis, and stroke. Reactive oxygen species (ROS), especially mitochondrial ROS, play a key role in regulating the cellular redox status, and an overproduction of ROS may in part underlie the pathogenesis of diabetes and other age-related diseases. Cells have evolved endogenous defense mechanisms against sustained oxidative stress such as the redox-sensitive transcription factor nuclear factor E2-related factor 2 (Nrf2), which regulates antioxidant response element (ARE/electrophile response element)-mediated expression of detoxifying and antioxidant enzymes and the cystine/glutamate transporter involved in glutathione biosynthesis. We hypothesize that diminished Nrf2/ARE activity contributes to increased oxidative stress and mitochondrial dysfunction in the vasculature leading to endothelial dysfunction, insulin resistance, and abnormal angiogenesis observed in diabetes. Sustained hyperglycemia further exacerbates redox dysregulation, thereby providing a positive feedback loop for severe diabetic complications. This review focuses on the role that Nrf2/ARE-linked gene expression plays in regulating endothelial redox homeostasis in health and type 2 diabetes, highlighting recent evidence that Nrf2 may provide a therapeutic target for countering oxidative stress associated with vascular disease and aging.

  14. Sulforaphane enhances the activity of the Nrf2-ARE pathway and attenuates inflammation in OxyHb-induced rat vascular smooth muscle cells.

    PubMed

    Zhao, X-D; Zhou, Y-T; Lu, X-J

    2013-09-01

    A growing body of evidence indicates that the nuclear factor erythroid 2-related factor 2-antioxidant response element (Nrf2-ARE) pathway plays a protective role in many physiological stress processes such as inflammatory damage, oxidative stress, and the accumulation of toxic metabolites, which are all involved in the cerebral vasospasm following subarachnoid hemorrhage (SAH). We hypothesized that the Nrf2-ARE pathway might have a protective role in cerebral vasospasm following SAH. In our study, we investigate whether the oxyhemoglobin (OxyHb) can induce the activation of the Nrf2-ARE pathway in vascular smooth muscle cells (VSMCs), and evaluate the modulatory effects of sulforaphane (SUL) on OxyHb-induced inflammation in VSMCs. As a result, both the protein level and the mRNA level of the nuclear Nrf2 were significantly increased, while the mRNA levels of two Nrf2-regulated gene products, both heme oxygenase-1 and NAD(P)H: quinone oxidoreductase-1, were also up-regulated in VSMCs induced with OxyHb. A marked increase of inflammatory cytokines such as IL-1β, IL-6 and TNF-α release was observed at 48 h after cells were treated with OxyHb. SUL enhanced the activity of the Nrf2-ARE pathway and suppressed cytokine release. Our results indicate that the Nrf2-ARE pathway was activated in OxyHb-induced VSMCs. SUL suppressed cytokine release via the activation of the Nrf2-ARE pathway in OxyHb-induced VSMCs.

  15. Ethanol Induction of CYP2A5: Role of CYP2E1-ROS-Nrf2 Pathway

    PubMed Central

    Lu, Yongke; Zhang, Xu Hannah

    2012-01-01

    Chronic ethanol consumption was previously shown to induce CYP2A5 in mice, and this induction of CYP2A5 by ethanol was CYP2E1 dependent. In this study, the mechanisms of CYP2E1-dependent ethanol induction of CYP2A5 were investigated. CYP2E1 was induced by chronic ethanol consumption to the same degree in wild-type (WT) mice and CYP2A5 knockout (Cyp2a5 –/–) mice, suggesting that unlike the CYP2E1-dependent ethanol induction of CYP2A5, ethanol induction of CYP2E1 is not CYP2A5 dependent. Microsomal ethanol oxidation was about 25% lower in Cyp2a5 –/– mice compared with that in WT mice, suggesting that CYP2A5 can oxidize ethanol although to a lesser extent than CYP2E1 does. CYP2A5 was induced by short-term ethanol consumption in human CYP2E1 transgenic knockin (Cyp2e1 –/– KI) mice but not in CYP2E1 knockout (Cyp2e1 –/–) mice. The redox-sensitive transcription factor nuclear factor-erythroid 2-related factor 2 (Nrf2) was also induced by acute ethanol in Cyp2e1 –/– KI mice but not in Cyp2e1 –/– mice. Ethanol induction of CYP2A5 in Nrf2 knockout (Nrf2 –/–) mice was lower compared with that in WT mice, whereas CYP2E1 induction by ethanol was comparable in WT and Nrf2 –/– mice. Antioxidants (N-acetyl-cysteine and vitamin C), which blocked oxidative stress induced by chronic ethanol in WT mice and acute ethanol in Cyp2e1 –/– KI mice, also blunted the induction of CYP2A5 and Nrf2 by ethanol but not the induction of CYP2E1 by ethanol. These results suggest that oxidative stress induced by ethanol via induction of CYP2E1 upregulates Nrf2 activity, which in turn regulates ethanol induction of CYP2A5. Results obtained from primary hepatocytes, mice gavaged with binge ethanol or fed chronic ethanol, show that Nrf2-regulated ethanol induction of CYP2A5 protects against ethanol-induced steatosis. PMID:22552773

  16. Bardoxolone Methyl Decreases Megalin and Activates Nrf2 in the Kidney

    PubMed Central

    Chertow, Glenn M.; Hebbar, Sudarshan; Vaziri, Nosratola D.; Ward, Keith W.; Meyer, Colin J.

    2012-01-01

    Inflammation and oxidative stress are hallmarks and mediators of the progression of CKD. Bardoxolone methyl, a potent activator of the nuclear factor erythroid 2–related factor 2 (Nrf2)–mediated antioxidant and anti-inflammatory response, increases estimated GFR and decreases BUN, serum phosphorus, and uric acid concentrations in patients with moderate to severe CKD. However, it also increases albuminuria, which is associated with inflammation and disease progression. Therefore, we investigated whether this bardoxolone methyl–induced albuminuria may result from the downregulation of megalin, a protein involved in the tubular reabsorption of albumin and lipid-bound proteins. Administration of bardoxolone methyl to cynomolgus monkeys significantly decreased the protein expression of renal tubular megalin, which inversely correlated with the urine albumin-to-creatinine ratio. Moreover, daily oral administration of bardoxolone methyl to monkeys for 1 year did not lead to any adverse effects on renal histopathologic findings but did reduce serum creatinine and BUN, as observed in patients with CKD. Finally, the bardoxolone methyl–induced decrease in megalin corresponded with pharmacologic induction of renal Nrf2 targets, including NAD(P)H:quinone oxidoreductase 1 enzyme activity and glutathione content. This result indicates that Nrf2 may have a role in megalin regulation. In conclusion, these data suggest that the increase in albuminuria that accompanies bardoxolone methyl administration may result, at least in part, from reduced expression of megalin, which seems to occur without adverse effects and with strong induction of Nrf2 targets. PMID:22859857

  17. Bardoxolone methyl decreases megalin and activates nrf2 in the kidney.

    PubMed

    Reisman, Scott A; Chertow, Glenn M; Hebbar, Sudarshan; Vaziri, Nosratola D; Ward, Keith W; Meyer, Colin J

    2012-10-01

    Inflammation and oxidative stress are hallmarks and mediators of the progression of CKD. Bardoxolone methyl, a potent activator of the nuclear factor erythroid 2-related factor 2 (Nrf2)-mediated antioxidant and anti-inflammatory response, increases estimated GFR and decreases BUN, serum phosphorus, and uric acid concentrations in patients with moderate to severe CKD. However, it also increases albuminuria, which is associated with inflammation and disease progression. Therefore, we investigated whether this bardoxolone methyl-induced albuminuria may result from the downregulation of megalin, a protein involved in the tubular reabsorption of albumin and lipid-bound proteins. Administration of bardoxolone methyl to cynomolgus monkeys significantly decreased the protein expression of renal tubular megalin, which inversely correlated with the urine albumin-to-creatinine ratio. Moreover, daily oral administration of bardoxolone methyl to monkeys for 1 year did not lead to any adverse effects on renal histopathologic findings but did reduce serum creatinine and BUN, as observed in patients with CKD. Finally, the bardoxolone methyl-induced decrease in megalin corresponded with pharmacologic induction of renal Nrf2 targets, including NAD(P)H:quinone oxidoreductase 1 enzyme activity and glutathione content. This result indicates that Nrf2 may have a role in megalin regulation. In conclusion, these data suggest that the increase in albuminuria that accompanies bardoxolone methyl administration may result, at least in part, from reduced expression of megalin, which seems to occur without adverse effects and with strong induction of Nrf2 targets.

  18. Isothiocyanates Reduce Mercury Accumulation via an Nrf2-Dependent Mechanism during Exposure of Mice to Methylmercury

    PubMed Central

    Toyama, Takashi; Shinkai, Yasuhiro; Yasutake, Akira; Uchida, Koji; Yamamoto, Masayuki

    2011-01-01

    Background: Methylmercury (MeHg) exhibits neurotoxicity through accumulation in the brain. The transcription factor Nrf2 (nuclear factor erythroid 2-related factor 2) plays an important role in reducing the cellular accumulation of MeHg. Objectives: We investigated the protective effect of isothiocyanates, which are known to activate Nrf2, on the accumulation of mercury after exposure to MeHg in vitro and in vivo. Methods: We used primary mouse hepatocytes in in vitro experiments and mice as an in vivo model. We used Western blotting, luciferase assays, atomic absorption spectrometry assays, and MTT [3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyl tetrazolium bromide] assays, and we identified toxicity in mice based on hind-limb flaccidity and mortality. Results: The isothiocyanates 6-methylsulfinylhexyl isothiocyanate (6-HITC) and sulforaphane (SFN) activated Nrf2 and up-regulated downstream proteins associated with MeHg excretion, such as glutamate-cysteine ligase, glutathione S-transferase, and multidrug resistance–associated protein, in primary mouse hepatocytes. Under these conditions, intracellular glutathione levels increased in wild-type but not Nrf2-deficient primary mouse hepatocytes. Pretreatment with 6-HITC and SFN before MeHg exposure suppressed cellular accumulation of mercury and cytotoxicity in wild-type but not Nrf2-deficient primary mouse hepatocytes. In comparison, in vivo administration of MeHg to Nrf2-deficient mice resulted in increased sensitivity to mercury concomitant with an increase in mercury accumulation in the brain and liver. Injection of SFN before administration of MeHg resulted in a decrease in mercury accumulation in the brain and liver of wild-type, but not Nrf2-deficient, mice. Conclusions: Through activation of Nrf2, 6-HITC and SFN can suppress mercury accumulation and intoxication caused by MeHg intake. PMID:21382770

  19. NRF2: Translating the Redox Code.

    PubMed

    Tummala, Krishna S; Kottakis, Filippos; Bardeesy, Nabeel

    2016-10-01

    Cancer requires mechanisms to mitigate reactive oxygen species (ROS) generated during rapid growth, such as induction of the antioxidant transcription factor, Nrf2. However, the targets of ROS-mediated cytotoxicity are unclear. Recent studies in pancreatic cancer show that redox control by Nrf2 prevents cysteine oxidation of the mRNA translational machinery, thereby supporting efficient protein synthesis. Copyright © 2016 Elsevier Ltd. All rights reserved.

  20. The hypertension drug, verapamil, activates Nrf2 by promoting p62-dependent autophagic Keap1 degradation and prevents acetaminophen-induced cytotoxicity.

    PubMed

    Lee, Da Hyun; Park, Jeong Su; Lee, Yu Seol; Sung, Su Haeng; Lee, Yong-Ho; Bae, Soo Han

    2017-02-01

    Nuclear factor erythroid 2-related factor 2 (Nrf2) provides a cellular defense against oxidative stress by inducing the expression of antioxidant and detoxification enzymes. The calcium antagonist, verapamil, is an FDA-approved drug prescribed for the treatment of hypertension. Here, we show that verapamil acts as a potent Nrf2 activator without causing cytotoxicity, through degradation of Kelch-like ECH-associated protein 1 (Keap1), a Nrf2 repressor. Furthermore, verapamilinduced Keap1 degradation is prominently mediated by a p62-dependent autophagic pathway. Correspondingly, verapamil protects cells from acetaminophen-induced oxidative damage through Nrf2 activation. These results demonstrated the underlying mechanisms for the protective role of verapamil against acetaminophen-induced cytotoxicity. [BMB Reports 2017; 50(2): 91-96].

  1. MHY1485 ameliorates UV-induced skin cell damages via activating mTOR-Nrf2 signaling.

    PubMed

    Yang, Bo; Xu, Qiu-Yun; Guo, Chun-Yan; Huang, Jin-Wen; Wang, Shu-Mei; Li, Yong-Mei; Tu, Ying; He, Li; Bi, Zhi-Gang; Ji, Chao; Cheng, Bo

    2017-02-21

    Ultra Violet (UV)-caused skin cell damage is a main cause of skin cancer. Here, we studied the activity of MHY1485, a mTOR activator, in UV-treated skin cells. In primary human skin keratinocytes, HaCaT keratinocytes and human skin fibroblasts, MHY1485 ameliorated UV-induced cell death and apoptosis. mTOR activation is required for MHY1485-induced above cytoprotective actions. mTOR kinase inhibitors (OSI-027, AZD-8055 and AZD-2014) or mTOR shRNA knockdown almost abolished MHY1485-induced cytoprotection. Further, MHY1485 treatment in skin cells activated mTOR downstream NF-E2-related factor 2 (Nrf2) signaling, causing Nrf2 Ser-40 phosphorylation, stabilization/upregulation and nuclear translocation, as well as mRNA expression of Nrf2-dictated genes. Contrarily, Nrf2 knockdown or S40T mutation almost nullified MHY1485-induced cytoprotection. MHY1485 suppressed UV-induced reactive oxygen species production and DNA single strand breaks in skin keratinocytes and fibroblasts. Together, we conclude that MHY1485 inhibits UV-induced skin cell damages via activating mTOR-Nrf2 signaling.

  2. Identification of an Unfavorable Immune Signature in Advanced Lung Tumors from Nrf2-Deficient Mice.

    PubMed

    Zhang, Di; Rennhack, Jonathan; Andrechek, Eran R; Rockwell, Cheryl E; Liby, Karen T

    2018-04-16

    Activation of the nuclear factor (erythroid-derived 2)-like 2 (Nrf2) pathway in normal cells inhibits carcinogenesis, whereas constitutive activation of Nrf2 in cancer cells promotes tumor growth and chemoresistance. However, the effects of Nrf2 activation in immune cells during lung carcinogenesis are poorly defined and could either promote or inhibit cancer growth. Our studies were designed to evaluate tumor burden and identify immune cell populations in the lungs of Nrf2 knockout (KO) versus wild-type (WT) mice challenged with vinyl carbamate. Nrf2 KO mice developed lung tumors earlier than the WT mice and exhibited more and larger tumors over time, even at late stages. T cell populations were lower in the lungs of Nrf2 KO mice, whereas tumor-promoting macrophages and myeloid-derived suppressor cells were elevated in the lungs and spleen, respectively, of Nrf2 KO mice relative to WT mice. Moreover, 34 immune response genes were significantly upregulated in tumors from Nrf2 KO mice, especially a series of cytokines (Cxcl1, Csf1, Ccl9, Cxcl12, etc.) and major histocompatibility complex antigens that promote tumor growth. Our studies discovered a novel immune signature, characterized by the infiltration of tumor-promoting immune cells, elevated cytokines, and increased expression of immune response genes in the lungs and tumors of Nrf2 KO mice. A complementary profile was also found in lung cancer patients, supporting the clinical significance of our findings. Overall, our results confirmed a protective role for Nrf2 in late-stage carcinogenesis and, unexpectedly, suggest that activation of Nrf2 in immune cells may be advantageous for preventing or treating lung cancer. Antioxid. Redox Signal. 00, 000-000.

  3. Nuclear factor erythroid-derived 2-related factor 2 activates glutathione S-transferase expression in the midgut of Spodoptera litura (Lepidoptera: Noctuidae) in response to phytochemicals and insecticides.

    PubMed

    Chen, S; Lu, M; Zhang, N; Zou, X; Mo, M; Zheng, S

    2018-05-10

    Detoxication enzymes play an important role in insect resistance to xenobiotics such as insecticides and phytochemicals. We studied the pathway for activating the expression of glutathione S-transferases (GSTs) in response to selected xenobiotics. An assay of the promoter activity of GST epsilon 1 (Slgste1) of Spodoptera litura led to the discovery of a cis-regulating element. An antioxidant response element was activated in response to indole-3-carbinol (I3C) and chlorpyrifos (CPF) and was able to bind with the xenobiotic sensor protein nuclear factor erythroid-derived 2-related factor 2 (SlNrf2). SlNrf2 and Slgste1 were responsive to reactive oxygen species induced by I3C and CPF in a S. litura cell line, as well as in S. litura midguts. SlNrf2 RNA interference (RNAi) reduced the message RNA levels of Slgste1 and the peroxidase activity of GSTs in response to I3C, xanthotoxin, CPF and deltamethrin. SlNrf2 RNAi and inhibitor treatment of GST activity decreased the viability of I3C-treated cells. These results indicate that SlNrf2 activates the expression of GSTs in response to oxidative stresses caused by exposure to xenobiotics. © 2018 The Royal Entomological Society.

  4. Low-Concentration Tributyltin Decreases GluR2 Expression via Nuclear Respiratory Factor-1 Inhibition

    PubMed Central

    Ishida, Keishi; Aoki, Kaori; Takishita, Tomoko; Miyara, Masatsugu; Sakamoto, Shuichiro; Sanoh, Seigo; Kimura, Tomoki; Kanda, Yasunari; Ohta, Shigeru; Kotake, Yaichiro

    2017-01-01

    Tributyltin (TBT), which has been widely used as an antifouling agent in paints, is a common environmental pollutant. Although the toxicity of high-dose TBT has been extensively reported, the effects of low concentrations of TBT are relatively less well studied. We have previously reported that low-concentration TBT decreases α-amino-3-hydroxy-5-methylisoxazole-4-propionic acid (AMPA)-type glutamate receptor subunit 2 (GluR2) expression in cortical neurons and enhances neuronal vulnerability to glutamate. However, the mechanism of this TBT-induced GluR2 decrease remains unknown. Therefore, we examined the effects of TBT on the activity of transcription factors that control GluR2 expression. Exposure of primary cortical neurons to 20 nM TBT for 3 h to 9 days resulted in a decrease in GluR2 mRNA expression. Moreover, TBT inhibited the DNA binding activity of nuclear respiratory factor-1 (NRF-1), a transcription factor that positively regulates the GluR2. This result indicates that TBT inhibits the activity of NRF-1 and subsequently decreases GluR2 expression. In addition, 20 nM TBT decreased the expression of genes such as cytochrome c, cytochrome c oxidase (COX) 4, and COX 6c, which are downstream of NRF-1. Our results suggest that NRF-1 inhibition is an important molecular action of the neurotoxicity induced by low-concentration TBT. PMID:28800112

  5. Low-Concentration Tributyltin Decreases GluR2 Expression via Nuclear Respiratory Factor-1 Inhibition.

    PubMed

    Ishida, Keishi; Aoki, Kaori; Takishita, Tomoko; Miyara, Masatsugu; Sakamoto, Shuichiro; Sanoh, Seigo; Kimura, Tomoki; Kanda, Yasunari; Ohta, Shigeru; Kotake, Yaichiro

    2017-08-11

    Tributyltin (TBT), which has been widely used as an antifouling agent in paints, is a common environmental pollutant. Although the toxicity of high-dose TBT has been extensively reported, the effects of low concentrations of TBT are relatively less well studied. We have previously reported that low-concentration TBT decreases α-amino-3-hydroxy-5-methylisoxazole-4-propionic acid (AMPA)-type glutamate receptor subunit 2 ( GluR2 ) expression in cortical neurons and enhances neuronal vulnerability to glutamate. However, the mechanism of this TBT-induced GluR2 decrease remains unknown. Therefore, we examined the effects of TBT on the activity of transcription factors that control GluR2 expression. Exposure of primary cortical neurons to 20 nM TBT for 3 h to 9 days resulted in a decrease in GluR2 mRNA expression. Moreover, TBT inhibited the DNA binding activity of nuclear respiratory factor-1 (NRF-1), a transcription factor that positively regulates the GluR2 . This result indicates that TBT inhibits the activity of NRF-1 and subsequently decreases GluR2 expression. In addition, 20 nM TBT decreased the expression of genes such as cytochrome c, cytochrome c oxidase (COX) 4, and COX 6c, which are downstream of NRF-1. Our results suggest that NRF-1 inhibition is an important molecular action of the neurotoxicity induced by low-concentration TBT.

  6. The Role of Nrf2-Mediated Pathway in Cardiac Remodeling and Heart Failure

    PubMed Central

    Sun, Wanqing; Zhang, Zhiguo; Zheng, Yang

    2014-01-01

    Heart failure (HF) is frequently the consequence of sustained, abnormal neurohormonal, and mechanical stress and remains a leading cause of death worldwide. The key pathophysiological process leading to HF is cardiac remodeling, a term referring to maladaptation to cardiac stress at the molecular, cellular, tissue, and organ levels. HF and many of the conditions that predispose one to HF are associated with oxidative stress. Increased generation of reactive oxygen species (ROS) in the heart can directly lead to increased necrosis and apoptosis of cardiomyocytes which subsequently induce cardiac remodeling and dysfunction. Nuclear factor-erythroid-2- (NF-E2-) related factor 2 (Nrf2) is a transcription factor that controls the basal and inducible expression of a battery of antioxidant genes and other cytoprotective phase II detoxifying enzymes that are ubiquitously expressed in the cardiovascular system. Emerging evidence has revealed that Nrf2 and its target genes are critical regulators of cardiovascular homeostasis via the suppression of oxidative stress, which is the key player in the development and progression of HF. The purpose of this review is to summarize evidence that activation of Nrf2 enhances endogenous antioxidant defenses and counteracts oxidative stress-associated cardiac remodeling and HF. PMID:25101151

  7. Phytochemicals and botanical extracts regulate NF-κB and Nrf2/ARE reporter activities in DI TNC1 astrocytes

    PubMed Central

    Ajit, Deepa; Simonyi, Agnes; Li, Runting; Chen, Zihong; Hannink, Mark; Fritsche, Kevin L.; Mossine, Valeri V.; Smith, Robert E.; Dobbs, Thomas K.; Luo, Rensheng; Folk, William R.; Gu, Zezong; Lubahn, Dennis B.; Weisman, Gary A.; Sun, Grace Y.

    2016-01-01

    The increase in oxidative stress and inflammatory responses associated with neurodegenerative diseases has drawn considerable attention towards understanding the transcriptional signaling pathways involving NF-κB (nuclear factor kappa-light-chain-enhancer of activated B cells) and Nrf2 (Nuclear Factor Erythroid 2-like 2). Our recent studies with immortalized murine microglial cells (BV-2) demonstrated effects of botanical polyphenols to inhibit lipopolysaccharide (LPS)-induced nitric oxide (NO) and enhance Nrf2-mediated antioxidant responses (Sun et al., 2015). In this study, an immortalized rat astrocyte (DI TNC1) cell line expressing a luciferase reporter driven by the NF-κB or the Nrf2/Antioxidant Response Element (ARE) promoter was used to assess regulation of these two pathways by phytochemiscals such as quercetin, rutin, cyanidin, cyanidin-3-O-glucoside, as well as botanical extracts from Withania somnifera (Ashwagandha), Sutherlandia frutescens (Sutherlandia) and Euterpe oleracea (Açaí). Quercetin effectively inhibited LPS-induced NF-κB reporter activity and stimulated Nrf2/ARE reporter activity in DI TNC1 astrocytes. Cyanidin and the glycosides showed similar effects but only at much higher concentrations. All three botanical extracts effectively inhibited LPS-induced NF-κB reporter activity. These extracts were capable of enhancing ARE activity by themselves and further enhanced ARE activity in the presence of LPS. Quercetin and botanical extracts induced Nrf2 and HO-1 protein expression. Interestingly, Ashwagandha extract was more active in inducing Nrf2 and HO-1 expression in DI TNC1 astrocytes as compared to Sutherlandia and Açaí extracts. In summary, this study demonstrated NF-kB and Nrf2/ARE promotor activities in DI TNC1 astrocytes, and further showed differences in ability for specific botanical polyphenols and extracts to down-regulate LPS-induced NF-kB and up-regulate the NRF2/ARE activities in these cells. PMID:27166148

  8. Synthetic Lignan Secoisolariciresinol Diglucoside (LGM2605) Reduces Asbestos-Induced Cytotoxicity in an Nrf2-Dependent and -Independent Manner

    PubMed Central

    Pietrofesa, Ralph A.; Chatterjee, Shampa; Park, Kyewon; Arguiri, Evguenia; Albelda, Steven M.; Christofidou-Solomidou, Melpo

    2018-01-01

    Asbestos exposure triggers inflammatory processes associated with oxidative stress and tissue damage linked to malignancy. LGM2605 is the synthetic lignan secoisolariciresinol diglucoside (SDG) with free radical scavenging, antioxidant, and anti-inflammatory properties in diverse inflammatory cell and mouse models, including exposure to asbestos fibers. Nuclear factor-E2 related factor 2 (Nrf2) activation and boosting of endogenous tissue defenses were associated with the protective action of LGM2605 from asbestos-induced cellular damage. To elucidate the role of Nrf2 induction by LGM2605 in protection from asbestos-induced cellular damage, we evaluated LGM2605 in asbestos-exposed macrophages from wild-type (WT) and Nrf2 disrupted (Nrf2−/−) mice. Cells were pretreated with LGM2605 (50 µM and 100 µM) and exposed to asbestos fibers (20 µg/cm2) and evaluated 8 h and 24 h later for inflammasome activation, secreted cytokine levels (interleukin-1β (IL-1β), interleukin-18 (IL-18), interleukin-6 (IL-6), and tumor necrosis factor alpha (TNFα)), cytotoxicity and cell death, nitrosative stress, and Nrf2-regulated enzyme levels. Asbestos exposure induced robust oxidative and nitrosative stress, cell death and cytotoxicity, which were equally mitigated by LGM2605. Inflammasome activation was significantly attenuated in Nrf2−/− macrophages compared to WT, and the protective action of LGM2605 was seen only in WT cells. In conclusion, in a cell model of asbestos-induced toxicity, LGM2605 acts via protective mechanisms that may not involve Nrf2 activation. PMID:29498660

  9. PM2.5 induces Nrf2-mediated defense mechanisms against oxidative stress by activating PIK3/AKT signaling pathway in human lung alveolar epithelial A549 cells.

    PubMed

    Deng, Xiaobei; Rui, Wei; Zhang, Fang; Ding, Wenjun

    2013-06-01

    It has been well documented in in vitro studies that ambient airborne particulate matter (PM) with an aerodynamic diameter less than 2.5 μm (PM(2.5)) is capable of inducing oxidative stress, which plays a key role in PM(2.5)-mediated cytotoxicity. Although nuclear factor erythroid-2-related factor 2 (Nrf2) has been shown to regulate the intracellular defense mechanisms against oxidative stress, a potential of the Nrf2-mediated cellular defense against oxidative stress induced by PM(2.5) remains to be determined. This study was aimed to explore the potential signaling pathway of Nrf2-mediated defense mechanisms against PM(2.5)-induced oxidative stress in human type II alveolar epithelial A549 cells. We exposed A549 cells to PM(2.5) particles collected from Beijing at a concentration of 16 μg/cm(2). We observed that PM(2.5) triggered an increase of intracellular reactive oxygen species (ROS) in a time-dependent manner during a period of 2 h exposure. We also found that Nrf2 overexpression suppressed and Nrf2 knockdown increased PM(2.5)-induced ROS generation. Using Western blot and confocal microscopy, we found that PM(2.5) exposure triggered significant translocation of Nrf2 into nucleus, resulting in AKT phosphorylation and significant transcription of ARE-driven phases II enzyme genes, such as NAD(P)H:quinone oxidoreductase (NQO-1), heme oxygenase-1 (HO-1), and glutamate-cysteine ligase catalytic subunit (GCLC) in A549 cells. Evaluation of signaling pathways showed that a phosphatidylinositol 3-kinase (PI3K) inhibitor (LY294002), but not an ERK 1/2 inhibitor (PD98059) or a p38 MAPK (SB203580), significantly down-regulated PM(2.5)-induced Nrf2 nuclear translocation and HO-1 mRNA expression, indicating PI3K/AKT is involved in the signaling pathway leads to the PM(2.5)-induced nuclear translocation of Nrf2 and subsequent Nrf2-mediated HO-1 transcription. Taken together, our results suggest that PM(2.5)-induced ROS may function as signaling molecules to activate Nrf

  10. Ursolic acid sensitizes cisplatin-resistant HepG2/DDP cells to cisplatin via inhibiting Nrf2/ARE pathway

    PubMed Central

    Wu, Shouhai; Zhang, Tianpeng; Du, Jingsheng

    2016-01-01

    Background Combinations of adjuvant sensitizers with anticancer drugs is a promising new strategy to reverse chemoresistance. Ursolic acid (UA) is one of the natural pentacyclic triterpene compounds known to have many pharmacological characteristics such as anti-inflammatory and anticancer properties. This study investigates whether UA can sensitize hepatocellular carcinoma cells to cisplatin. Materials and methods Cells were transfected with nuclear factor erythroid-2-related factor 2 (Nrf2) small interfering RNA and Nrf2 complementary DNA by using Lipofectin 2000. The cytotoxicity of cells was investigated by Cell Counting Kit 8 assay. Cell apoptosis, cell cycle, reactive oxygen species, and mitochondrial membrane potential were detected by flow cytometry fluorescence-activated cell sorting. The protein level of Nrf2, NAD(P)H quinone oxidoreductase 1 (NQO1), glutathione S-transferase (GST), and heme oxygenase-1 (HO-1) was detected by Western blot analysis. Results The results showed that the reverse index was 2.9- and 9.69-fold by UA of 1.125 μg/mL and 2.25 μg/mL, respectively, for cisplatin to HepG2/DDP cells. UA–cisplatin combination induced cell apoptosis and reactive oxygen species, blocked the cell cycle in G0/G1 phase, and reduced the mitochondrial membrane potential. Mechanistically, UA–cisplatin dramatically decreased the expression of Nrf2 and its downstream genes. The sensibilization of UA–cisplatin combination was diminished in Nrf2 small interfering RNA-transfected HepG2/DDP cells, as well as in Nrf2 complementary DNA-transfected HepG2/DDP cells. Conclusion The results confirmed the sensibilization of UA on HepG2/DDP cells to cisplatin, which was possibly mediated via the Nrf2/antioxidant response element pathway. PMID:27822011

  11. A prenylated flavonoid, 10-oxomornigrol F, exhibits anti-inflammatory effects by activating the Nrf2/heme oxygenase-1 pathway in macrophage cells.

    PubMed

    Tran, Phi-Long; Tran, Phuong Thao; Tran, Huynh Nguyen Khanh; Lee, Suhyun; Kim, Okwha; Min, Buyng-Sun; Lee, Jeong-Hyung

    2018-02-01

    Prenylated flavonoids are a unique class of naturally occurring flavonoids that have various pharmacological activities. In the present study, we investigated the anti-inflammatory effect in murine macrophages of a prenylated flavonoid, 10-oxomornigrol F (OMF), which was isolated from the twigs of Morus alba (Moraceae). OMF inhibited the lipopolysaccharide (LPS)-induced production of nitric oxide (NO), tumor necrosis factor-α (TNF-α), interleukin (IL)-1β, and IL-6 in RAW264.7 cells, as well as in mouse bone marrow-derived macrophages (BMMs). OMF also rescued LPS-induced septic mortality in ICR mice. LPS-induced expression of inducible nitric oxide synthase (iNOS), cyclooxygenase-2 (COX-2), TNF-α and IL-6 was also significantly suppressed by OMF treatment in RAW264.7 cells. Treatment of RAW264.7 cells with OMF induced heme oxygenase (HO)-1 mRNA and protein expression and increased the nuclear translocation of the nuclear factor-E2-related factor 2 (Nrf2) as well as the expression of Nrf2 target genes, such as NAD(P)H:quinone oxidoreductase 1 (NQO1). Treatment of RAW264.7 cells with OMF increased the intracellular level of reactive oxygen species (ROS) and the phosphorylation levels of p38 mitogen-activated protein kinase (MAPK); co-treatment with the antioxidant N-acetyl-cysteine (NAC) blocked this OMF-induced p38 MAPK phosphorylation. Moreover, NAC, or SB203580 (a p38 MAPK inhibitor), blocked the OMF-induced nuclear translocation of Nrf2 and HO-1 expression, suggesting that OMF induces HO-1 expression by activating Nrf2 through the p38 MAPK pathway. Consistent with the notion that the Nrf2/HO-1 pathway has anti-inflammatory properties, inhibiting HO-1 significantly abrogated the anti-inflammatory effects of OMF in LPS-stimulated RAW264.7 cells. Taken together, these findings suggest that OMF exerts its anti-inflammatory effect by activating the Nrf2/HO-1 pathway, and may be a potential Nrf2 activator to prevent or treat inflammatory diseases. Copyright © 2017

  12. Sulforaphane Prevents Angiotensin II-Induced Testicular Cell Death via Activation of NRF2.

    PubMed

    Wang, Yonggang; Wu, Hao; Xin, Ying; Bai, Yang; Kong, Lili; Tan, Yi; Liu, Feng; Cai, Lu

    2017-01-01

    Although angiotensin II (Ang II) was reported to facilitate sperm motility and intratesticular sperm transport, recent findings shed light on the efficacy of Ang II in stimulating inflammatory events in testicular peritubular cells, effect of which may play a role in male infertility. It is still unknown whether Ang II can induce testicular apoptotic cell death, which may be a more direct action of Ang II in male infertility. Therefore, the present study aims to determine whether Ang II can induce testicular apoptotic cell death and whether this action can be prevented by sulforaphane (SFN) via activating nuclear factor (erythroid-derived 2)-like 2 (NRF2), the governor of antioxidant-redox signalling. Eight-week-old male C57BL/6J wild type (WT) and Nrf2 gene knockout mice were treated with Ang II, in the presence or absence of SFN. In WT mice, SFN activated testicular NRF2 expression and function, along with a marked attenuation in Ang II-induced testicular oxidative stress, inflammation, endoplasmic reticulum stress, and apoptotic cell death. Deletion of the Nrf2 gene led to a complete abolishment of these efficacies of SFN. The present study indicated that Ang II may result in testicular apoptotic cell death, which can be prevented by SFN via the activation of NRF2.

  13. The involvement of Nrf2 in the protective effects of (-)-Epigallocatechin-3-gallate (EGCG) on NaAsO2-induced hepatotoxicity.

    PubMed

    Han, Xiao-Dong; Zhang, Yan-Yan; Wang, Ke-Lei; Huang, Yong-Pan; Yang, Zhong-Bao; Liu, Zhi

    2017-09-12

    Arsenic exposure produces hepatotoxicity. The common mechanism determining its toxicity is the generation of oxidative stress. Oxidative stress induced by arsenic leads to the activation of nuclear factor erythroid 2-related factor 2 (Nrf2) pathway. (-)-Epigallocatechin-3-gallate (EGCG) possesses a potent antioxidant capacity and exhibits extensive pharmacological activities. This study aims to evaluate effects of EGCG on arsenic-induced hepatotoxicity and activation of Nrf2 pathway. Plasma activities of alanine aminotransferase, aspartate aminotransferase, alkaline phosphatase, and lactate dehydrogenase were measured; Histological analyses were conducted to observe morphological changes; Biochemical indexes such as oxidative stress (Catalase (CAT), malonyldialdehyde (MDA), superoxide dismutase (SOD), glutathione (GSH), reactive oxygen species (ROS)), Nrf2 signaling related genes ( Nrf2, Nqo1, and Ho-1 ) were assessed. The results showed that EGCG inhibited arsenic-induced hepatic pathological damage, liver ROS level and MDA level. Arsenic decreases the antioxidant enzymes SOD, GPX, and CAT activity and the decrease was inhibited by treatment of EGCG. Furthermore, EGCG attenuated the retention of arsenic in liver tissues and improved the expressions of Nrf2 signaling related genes ( Nrf2, Nqo1, and Ho-1 ). These findings provide evidences that EGCG may be useful for reducing hepatotoxicity associated with oxidative stress by the activation of Nrf2 signaling pathway. Our findings suggest a possible mechanism of antioxidant EGCG in preventing hepatotoxicity, which implicate that EGCG may be a potential treatment for arsenicosis therapy.

  14. NRF2-ome: an integrated web resource to discover protein interaction and regulatory networks of NRF2.

    PubMed

    Türei, Dénes; Papp, Diána; Fazekas, Dávid; Földvári-Nagy, László; Módos, Dezső; Lenti, Katalin; Csermely, Péter; Korcsmáros, Tamás

    2013-01-01

    NRF2 is the master transcriptional regulator of oxidative and xenobiotic stress responses. NRF2 has important roles in carcinogenesis, inflammation, and neurodegenerative diseases. We developed an online resource, NRF2-ome, to provide an integrated and systems-level database for NRF2. The database contains manually curated and predicted interactions of NRF2 as well as data from external interaction databases. We integrated NRF2 interactome with NRF2 target genes, NRF2 regulating TFs, and miRNAs. We connected NRF2-ome to signaling pathways to allow mapping upstream NRF2 regulatory components that could directly or indirectly influence NRF2 activity totaling 35,967 protein-protein and signaling interactions. The user-friendly website allows researchers without computational background to search, browse, and download the database. The database can be downloaded in SQL, CSV, BioPAX, SBML, PSI-MI, and in a Cytoscape CYS file formats. We illustrated the applicability of the website by suggesting a posttranscriptional negative feedback of NRF2 by MAFG protein and raised the possibility of a connection between NRF2 and the JAK/STAT pathway through STAT1 and STAT3. NRF2-ome can also be used as an evaluation tool to help researchers and drug developers to understand the hidden regulatory mechanisms in the complex network of NRF2.

  15. Diabetic Wound Healing and Activation of Nrf2 by Herbal Medicine

    PubMed Central

    Senger, Donald R.; Cao, Shugeng

    2016-01-01

    Nrf2 defense is a very important cellular mechanism to control oxidative stress, which is implicated in wound healing. Nrf2 can induce many cytoprotective genes, including HO-1, NQO1 and G6PD. Among many natural products that have been reported as Nrf2 activators, sulforaphane and curcumin have been studied more widely than any others, and both are in clinical trials for non-cancerous disorders. Recently, we reported 4-ethyl catechol and 4-vinyl catechol as Nrf2 co-factors that can induce Nrf2 as potently as sulforaphane and curcumin. These new Nrf2 co-factors were identified in hot aqueous extract of an herbal medicine Barleria lupulina, and fermented Noni (Morinda citrifolia) juice, which are used traditionally for diabetic wound healing. PMID:27868087

  16. Structural and Functional Characterization of Nrf2 Degradation by the Glycogen Synthase Kinase 3/β-TrCP Axis

    PubMed Central

    Rada, Patricia; Rojo, Ana I.; Evrard-Todeschi, Nathalie; Innamorato, Nadia G.; Cotte, Axelle; Jaworski, Tomasz; Tobón-Velasco, Julio C.; Devijver, Herman; García-Mayoral, María Flor; Van Leuven, Fred; Hayes, John D.

    2012-01-01

    The transcription factor NF-E2-related factor 2 (Nrf2) is a master regulator of a genetic program, termed the phase 2 response, that controls redox homeostasis and participates in multiple aspects of physiology and pathology. Nrf2 protein stability is regulated by two E3 ubiquitin ligase adaptors, Keap1 and β-TrCP, the latter of which was only recently reported. Here, two-dimensional (2D) gel electrophoresis and site-directed mutagenesis allowed us to identify two serines of Nrf2 that are phosphorylated by glycogen synthase kinase 3β (GSK-3β) in the sequence DSGISL. Nuclear magnetic resonance studies defined key residues of this phosphosequence involved in docking to the WD40 propeller of β-TrCP, through electrostatic and hydrophobic interactions. We also identified three arginine residues of β-TrCP that participate in Nrf2 docking. Intraperitoneal injection of the GSK-3 inhibitor SB216763 led to increased Nrf2 and heme oxygenase-1 levels in liver and hippocampus. Moreover, mice with hippocampal absence of GSK-3β exhibited increased levels of Nrf2 and phase 2 gene products, reduced glutathione, and decreased levels of carbonylated proteins and malondialdehyde. This study establishes the structural parameters of the interaction of Nrf2 with the GSK-3/β-TrCP axis and its functional relevance in the regulation of Nrf2 by the signaling pathways that impinge on GSK-3. PMID:22751928

  17. Sirt1 activation prevents anti-Thy 1.1 mesangial proliferative glomerulonephritis in the rat through the Nrf2/ARE pathway.

    PubMed

    Huang, Kaipeng; Li, Ruiming; Wei, Wentao

    2018-08-05

    Mesangial proliferative glomerulonephritis (MsPGN) is characterized by glomerular mesangial cells proliferation and extracellular matrix deposition in mesangial area, which develop into glomerulosclerosis. Both silent information regulator 2-related protein 1 (Sirt1) and nuclear factor erythroid 2-related factor 2/anti-oxidant response element (Nrf2/ARE) pathway had remarkable renoprotective effects. However, whether Sirt1 and Nrf2/ARE pathway can regulate the pathological process of MsPGN remains unknown. Here, we found that Sirt1 activation by SRT1720 decreased mesangial hypercellularity and mesangial matrix areas, reduced renal Col4 and α-SMA expressions, lowered 24 h proteinuria, and eventually reduced FN and TGF-β1 expressions in rats received anti-Thy 1.1 IgG. Further study showed that SRT1720 markedly enhanced the activity of Nrf2/ARE pathway including promoting the nuclear content and ARE-binding ability of Nrf2, elevating the protein levels of HO-1 and SOD1, two target genes of Nrf2, which eventually increased total SOD activity and decreased malondialdehyde level in the kidney tissues of experimental anti-Thy 1.1 MsPGN rats. Taken together, Sirt1 prevented the pathological process of experimental anti-Thy 1.1 MsPGN through promoting the activation of Nrf2/ARE pathway, which warrants further elucidation. Sirt1 might be a potential therapeutic target for treating MsPGN. Copyright © 2018 Elsevier B.V. All rights reserved.

  18. Transcription factor Nrf2 hyperactivation in early-phase renal ischemia-reperfusion injury prevents tubular damage progression.

    PubMed

    Nezu, Masahiro; Souma, Tomokazu; Yu, Lei; Suzuki, Takafumi; Saigusa, Daisuke; Ito, Sadayoshi; Suzuki, Norio; Yamamoto, Masayuki

    2017-02-01

    Acute kidney injury is a devastating disease with high morbidity in hospitalized patients and contributes to the pathogenesis of chronic kidney disease. An underlying mechanism of acute kidney injury involves ischemia-reperfusion injury which, in turn, induces oxidative stress and provokes organ damage. Nrf2 is a master transcription factor that regulates the cellular response to oxidative stress. Here, we examined the role of Nrf2 in the progression of ischemia-reperfusion injury-induced kidney damage in mice using genetic and pharmacological approaches. Both global and tubular-specific Nrf2 activation enhanced gene expression of antioxidant and NADPH synthesis enzymes, including glucose-6-phosphate dehydrogenase, and ameliorated both the initiation of injury in the outer medulla and the progression of tubular damage in the cortex. Myeloid-specific Nrf2 activation was ineffective. Short-term administration of the Nrf2 inducer CDDO during the initial phase of injury ameliorated the late phase of tubular damage. This inducer effectively protected the human proximal tubular cell line HK-2 from oxidative stress-mediated cell death while glucose-6-phosphate dehydrogenase knockdown increased intracellular reactive oxygen species. These findings demonstrate that tubular hyperactivation of Nrf2 in the initial phase of injury prevents the progression of reactive oxygen species-mediated tubular damage by inducing antioxidant enzymes and NADPH synthesis. Thus, Nrf2 may be a promising therapeutic target for preventing acute kidney injury to chronic kidney disease transition. Copyright © 2016 International Society of Nephrology. Published by Elsevier Inc. All rights reserved.

  19. Sulforaphane Ameliorates Okadaic Acid-Induced Memory Impairment in Rats by Activating the Nrf2/HO-1 Antioxidant Pathway.

    PubMed

    Dwivedi, Subhash; Rajasekar, N; Hanif, Kashif; Nath, Chandishwar; Shukla, Rakesh

    2016-10-01

    Okadaic acid (OKA) causes memory impairment and attenuates nuclear factor erythroid 2-related factor 2 (Nrf2) along with oxidative stress and neuroinflammation in rats. Sulforaphane (dietary isothiocyanate compound), an activator of Nrf2 signaling, exhibits neuroprotective effects. However, the protective effect of sulforaphane in OKA-induced neurotoxicity remains uninvestigated. Therefore, in the present study, the role of sulforaphane in OKA-induced memory impairment in rats was explored. A significant increased Nrf2 expression in the hippocampus and cerebral cortex was observed in trained (Morris water maze) rats, and a significant decreased Nrf2 expression in memory-impaired (OKA, 200 ng icv) rats indicated its involvement in memory function. Sulforaphane administration (5 and 10 mg/kg, ip, days 1 and 2) ameliorates OKA-induced memory impairment in rats. The treatment also restored Nrf2 and its downstream antioxidant protein expression (GCLC, HO-1) and attenuated oxidative stress (ROS, nitrite, GSH), neuroinflammation (NF-κB, TNF-α, IL-10), and neuronal apoptosis in the cerebral cortex and hippocampus of OKA-treated rats. Further, to determine whether modulation of Nrf2 signaling is responsible for the protective effect of sulforaphane, in vitro, Nrf2 siRNA and its downstream HO-1 inhibition studies were carried out in a rat astrocytoma cell line (C6). The protective effects of sulforaphane were abolished with Nrf2 siRNA and HO-1 inhibition in astrocytes. The results suggest that Nrf2-dependent activation of cellular antioxidant machinery results in sulforaphane-mediated protection against OKA-induced memory impairment in rats. Graphical Abstract ᅟ.

  20. Astrocyte NMDA receptors' activity sustains neuronal survival through a Cdk5–Nrf2 pathway

    PubMed Central

    Jimenez-Blasco, D; Santofimia-Castaño, P; Gonzalez, A; Almeida, A; Bolaños, J P

    2015-01-01

    Neurotransmission unavoidably increases mitochondrial reactive oxygen species. However, the intrinsic antioxidant defense of neurons is weak and hence the mechanism whereby these cells are physiologically protected against oxidative damage is unknown. Here we found that the antioxidant defense of neurons is repressed owing to the continuous protein destabilization of the master antioxidant transcriptional activator, nuclear factor-erythroid 2-related factor-2 (Nrf2). By contrast, Nrf2 is highly stable in neighbor astrocytes explaining their robust antioxidant defense and resistance against oxidative stress. We also show that subtle and persistent stimulation of N-methyl-d-aspartate receptors (NMDAR) in astrocytes, through a mechanism not requiring extracellular Ca2+ influx, upregulates a signal transduction pathway involving phospholipase C-mediated endoplasmic reticulum release of Ca2+ and protein kinase Cδ activation. Active protein kinase Cδ promotes, by phosphorylation, the stabilization of p35, a cyclin-dependent kinase-5 (Cdk5) cofactor. Active p35/Cdk5 complex in the cytosol phosphorylates Nrf2 at Thr395, Ser433 and Thr439 that is sufficient to promote Nrf2 translocation to the nucleus and induce the expression of antioxidant genes. Furthermore, this Cdk5–Nrf2 transduction pathway boosts glutathione metabolism in astrocytes efficiently protecting closely spaced neurons against oxidative damage. Thus, intercellular communication through NMDAR couples neurotransmission with neuronal survival. PMID:25909891

  1. PPARβ/δ ameliorates fructose-induced insulin resistance in adipocytes by preventing Nrf2 activation.

    PubMed

    Barroso, Emma; Rodríguez-Rodríguez, Rosalía; Chacón, Matilde R; Maymó-Masip, Elsa; Ferrer, Laura; Salvadó, Laia; Salmerón, Emilio; Wabistch, Martin; Palomer, Xavier; Vendrell, Joan; Wahli, Walter; Vázquez-Carrera, Manuel

    2015-05-01

    We studied whether PPARβ/δ deficiency modifies the effects of high fructose intake (30% fructose in drinking water) on glucose tolerance and adipose tissue dysfunction, focusing on the CD36-dependent pathway that enhances adipose tissue inflammation and impairs insulin signaling. Fructose intake for 8 weeks significantly increased body and liver weight, and hepatic triglyceride accumulation in PPARβ/δ-deficient mice but not in wild-type mice. Feeding PPARβ/δ-deficient mice with fructose exacerbated glucose intolerance and led to macrophage infiltration, inflammation, enhanced mRNA and protein levels of CD36, and activation of the JNK pathway in white adipose tissue compared to those of water-fed PPARβ/δ-deficient mice. Cultured adipocytes exposed to fructose also exhibited increased CD36 protein levels and this increase was prevented by the PPARβ/δ activator GW501516. Interestingly, the levels of the nuclear factor E2-related factor 2 (Nrf2), a transcription factor reported to up-regulate Cd36 expression and to impair insulin signaling, were increased in fructose-exposed adipocytes whereas co-incubation with GW501516 abolished this increase. In agreement with Nrf2 playing a role in the fructose-induced CD36 protein level increases, the Nrf2 inhibitor trigonelline prevented the increase and the reduction in insulin-stimulated AKT phosphorylation caused by fructose in adipocytes. Protein levels of the well-known Nrf2 target gene quinone oxidoreductase 1 (Nqo1) were increased in water-fed PPARβ/δ-null mice, suggesting that PPARβ/δ deficiency increases Nrf2 activity; and this increase was exacerbated in fructose-fed PPARβ/δ-deficient mice. These findings indicate that the combination of high fructose intake and PPARβ/δ deficiency increases CD36 protein levels via Nrf2, a process that promotes chronic inflammation and insulin resistance in adipose tissue. Copyright © 2015 Elsevier B.V. All rights reserved.

  2. Cyclo(His-Pro) promotes cytoprotection by activating Nrf2-mediated up-regulation of antioxidant defence

    PubMed Central

    Minelli, Alba; Conte, Carmela; Grottelli, Silvia; Bellezza, Maria; Cacciatore, Ivana; Bolaños, Juan P

    2009-01-01

    Hystidyl-proline [cyclo(His-Pro)] is an endogenous cyclic dipeptide produced by the cleavage of thyrotropin releasing hormone. Previous studies have shown that cyclo(His-Pro) protects against oxidative stress, although the underlying mechanism has remained elusive. Here, we addressed this issue and found that cyclo(His-Pro) triggered nuclear accumulation of NF-E2-related factor-2 (Nrf2), a transcription factor that up-regulates antioxidant-/electrophile-responsive element (ARE-EpRE)-related genes, in PC12 cells. Cyclo(His-Pro) attenuated reactive oxygen species production, and prevented glutathione depletion caused by glutamate, rotenone, paraquat and β-amyloid treatment. Moreover, real-time PCR analyses revealed that cyclo(His-Pro) induced the expression of a number of ARE-related genes and protected cells against hydrogen peroxide-mediated apoptotic death. Furthermore, these effects were abolished by RNA interference-mediated Nrf2 knockdown. Finally, pharmacological inhibition of p-38 MAPK partially prevented both cyclo(His-Pro)-mediated Nrf2 activation and cellular protection. These results suggest that the signalling mechanism responsible for the cytoprotective actions of cyclo(His-Pro) would involve p-38 MAPK activation leading to Nrf2-mediated up-regulation of antioxidant cellular defence. PMID:18373731

  3. Characterization of the Antioxidant Effects of γ-Oryzanol: Involvement of the Nrf2 Pathway

    PubMed Central

    Rungratanawanich, W.; Serafini, M. M.; Guarienti, M.; Catanzaro, M.; Marziano, M.; Memo, M.; Lanni, C.

    2018-01-01

    γ-Oryzanol (ORY) is well known for its antioxidant potential. However, the mechanism by which ORY exerts its antioxidant effect is still unclear. In this paper, the antioxidant properties of ORY were investigated for its potential effects as a reactive oxygen and nitrogen species (ROS/RNS) scavenger and in activating antioxidant-promoting intracellular pathways utilizing the human embryonic kidney cells (HEK-293). The 24 h ORY exposure significantly prevented hydrogen peroxide- (H2O2-) induced ROS/RNS production at 3 h, and this effect was sustained for at least 24 h. ORY pretreatment also enhanced the activity of antioxidant enzymes: superoxide dismutase (SOD) and glutathione peroxidase (GPX). Interestingly, ORY induced the nuclear factor (erythroid-derived 2)-like 2 (Nrf2) nuclear translocation and upregulation of Nrf2-dependent defensive genes such as NAD(P)H quinone reductase (NQO1), heme oxygenase-1 (HO-1), and glutathione synthetase (GSS) at mRNA and protein levels in both basal condition and after H2O2 insult. Thus, this study suggested an intriguing effect of ORY in modulating the Nrf2 pathway, which is also involved in regulating longevity as well as age-related diseases. PMID:29725495

  4. Characterization of the Antioxidant Effects of γ-Oryzanol: Involvement of the Nrf2 Pathway.

    PubMed

    Rungratanawanich, W; Abate, G; Serafini, M M; Guarienti, M; Catanzaro, M; Marziano, M; Memo, M; Lanni, C; Uberti, D

    2018-01-01

    γ -Oryzanol (ORY) is well known for its antioxidant potential. However, the mechanism by which ORY exerts its antioxidant effect is still unclear. In this paper, the antioxidant properties of ORY were investigated for its potential effects as a reactive oxygen and nitrogen species (ROS/RNS) scavenger and in activating antioxidant-promoting intracellular pathways utilizing the human embryonic kidney cells (HEK-293). The 24 h ORY exposure significantly prevented hydrogen peroxide- (H 2 O 2 -) induced ROS/RNS production at 3 h, and this effect was sustained for at least 24 h. ORY pretreatment also enhanced the activity of antioxidant enzymes: superoxide dismutase (SOD) and glutathione peroxidase (GPX). Interestingly, ORY induced the nuclear factor (erythroid-derived 2)-like 2 (Nrf2) nuclear translocation and upregulation of Nrf2-dependent defensive genes such as NAD(P)H quinone reductase (NQO1), heme oxygenase-1 (HO-1), and glutathione synthetase (GSS) at mRNA and protein levels in both basal condition and after H 2 O 2 insult. Thus, this study suggested an intriguing effect of ORY in modulating the Nrf2 pathway, which is also involved in regulating longevity as well as age-related diseases.

  5. Activating Nrf-2 Signaling Depresses Unilateral Ureteral Obstruction-Evoked Mitochondrial Stress-Related Autophagy, Apoptosis and Pyroptosis in Kidney

    PubMed Central

    Chung, Shue Dong; Lai, Ting Yu; Chien, Chiang Ting; Yu, Hong Jen

    2012-01-01

    Exacerbated oxidative stress and inflammation may induce three types of programmed cell death, autophagy, apoptosis and pyroptosis in unilateral ureteral obstruction (UUO) kidney. Sulforaphane activating NF-E2-related nuclear factor erythroid-2 (Nrf-2) signaling may ameliorate UUO-induced renal damage. UUO was induced in the left kidney of female Wistar rats. The level of renal blood flow, cortical and medullary oxygen tension and reactive oxygen species (ROS) was evaluated. Fibrosis, ED-1 (macrophage/monocyte) infiltration, oxidative stress, autophagy, apoptosis and pyroptosis were evaluated by immunohistochemistry and Western blot in UUO kidneys. Effects of sulforaphane, an Nrf-2 activator, on Nrf-2- and mitochondrial stress-related proteins and renal injury were examined. UUO decreased renal blood flow and oxygen tension and increased renal ROS, 3-nitrotyrosine stain, ED-1 infiltration and fibrosis. Enhanced renal tubular Beclin-1 expression started at 4 h UUO and further enhanced at 3d UUO, whereas increased Atg-5-Atg12 and LC3-II expression were found at 3d UUO. Increased renal Bax/Bcl-2 ratio, caspase 3 and PARP fragments, apoptosis formation associated with increased caspase 1 and IL-1β expression for pyroptosis formation were started from 3d UUO. UUO reduced nuclear Nrf-2 translocation, increased cytosolic and inhibitory Nrf-2 expression, increased cytosolic Bax translocation to mitochondrial and enhanced mitochondrial Cytochrome c release into cytosol of the UUO kidneys. Sulforaphane significantly increased nuclear Nrf-2 translocation and decreased mitochondrial Bax translocation and Cytochrome c release into cytosol resulting in decreased renal injury. In conclusion, sulforaphane via activating Nrf-2 signaling preserved mitochondrial function and suppressed UUO-induced renal oxidative stress, inflammation, fibrosis, autophagy, apoptosis and pyroptosis. PMID:23071780

  6. Interplay between the chalcone cardamonin and selenium in the biosynthesis of Nrf2-regulated antioxidant enzymes in intestinal Caco-2 cells.

    PubMed

    De Spirt, Silke; Eckers, Anna; Wehrend, Carina; Micoogullari, Mustafa; Sies, Helmut; Stahl, Wilhelm; Steinbrenner, Holger

    2016-02-01

    Selenoenzymes and nuclear factor erythroid 2-related factor 2 (Nrf2)-regulated phase II enzymes comprise key components of the cellular redox and antioxidant systems, which show multiple interrelations. Deficiency of the micronutrient selenium (Se) and impaired biosynthesis of selenoproteins have been reported to result in induction of Nrf2 target genes. Conversely, transcription of the selenoenzymes glutathione peroxidase 2 (GPx2) and thioredoxin reductase 1 (TrxR1) is up-regulated upon Nrf2 activation. Here, we have studied the interplay between Se and the secondary plant metabolite cardamonin, an Nrf2-activating chalcone, in the regulation of Nrf2-controlled antioxidant enzymes. Se-deficient and Se-repleted (sodium selenite-supplemented) human intestinal Caco-2 cells were exposed to cardamonin. Uptake of cardamonin by the Caco-2 cells was independent of their Se status. Cardamonin strongly induced gene expression of GPx2 and TrxR1. However, cardamonin treatment did not result in elevated GPx or TrxR activity and protein levels, possibly relating to a concomitant down-regulation of O-phosphoseryl-tRNA(Sec) kinase (PSTK), an enzyme involved in translation of selenoprotein mRNAs. On the other hand, induction of the Nrf2-regulated enzyme heme oxygenase 1 (HO-1) by cardamonin was diminished in Se-replete compared to Se-deficient cells. Our findings suggest that cardamonin interferes with the biosynthesis of Nrf2-regulated selenoenzymes, in contrast to the Nrf2-activating isothiocyanate compound sulforaphane, which has been shown earlier to synergize with Se-mediated cytoprotection. Conversely, the cellular Se status apparently affects the cardamonin-mediated induction of non-selenoprotein antioxidant enzymes such as HO-1. Copyright © 2015 Elsevier Inc. All rights reserved.

  7. Flavonoids as Putative Inducers of the Transcription Factors Nrf2, FoxO, and PPARγ

    PubMed Central

    Duckstein, Nils; Hasler, Mario; Rimbach, Gerald

    2017-01-01

    Dietary flavonoids have been shown to extend the lifespan of some model organisms and may delay the onset of chronic ageing-related diseases. Mechanistically, the effects could be explained by the compounds scavenging free radicals or modulating signalling pathways. Transcription factors Nrf2, FoxO, and PPARγ possibly affect ageing by regulating stress response, adipogenesis, and insulin sensitivity. Using Hek-293 cells transfected with luciferase reporter constructs, we tested the potency of flavonoids from different subclasses (flavonols, flavones, flavanols, and isoflavones) to activate these transcription factors. Under cell-free conditions (ABTS and FRAP assays), we tested their free radical scavenging activities and used α-tocopherol and ascorbic acid as positive controls. Most of the tested flavonoids, but not the antioxidant vitamins, stimulated Nrf2-, FoxO-, and PPARγ-dependent promoter activities. Flavonoids activating Nrf2 also tended to induce a FoxO and PPARγ response. Interestingly, activation patterns of cellular stress response by flavonoids were not mirrored by their activities in ABTS and FRAP assays, which depended mostly on hydroxylation in the flavonoid B ring and, in some cases, extended that of the vitamins. In conclusion, the free radical scavenging properties of flavonoids do not predict whether these molecules can stimulate a cellular response linked to activation of longevity-associated transcription factors. PMID:28761622

  8. Concerted action of p62 and Nrf2 protects cells from palmitic acid-induced lipotoxicity

    DOE Office of Scientific and Technical Information (OSTI.GOV)

    Park, Jeong Su; Yonsei Biomedical Research Institute, Yonsei University College of Medicine, 50 Yonsei-ro, Seodaemun-gu, Seoul 120-752; Kang, Dong Hoon

    Nonalcoholic fatty liver disease (NAFLD), frequently associated with obesity and diabetes mellitus, is caused by the accumulation of excess fatty acids within liver cells. Palmitic acid (PA), a common saturated fatty acid found in mammals, induces the generation of reactive oxygen species (ROS) and elicits apoptotic cell death, known as lipotoxicity. However, protective mechanisms against PA-induced lipotoxicity have not been elucidated. In this study, we aimed to clarify the role of p62, an adapter protein in the autophagic process, as well as the nuclear factor erythroid 2-related factor 2 (Nrf2)-Kelch-like ECH-associated protein 1 (Keap1) pathway, in protecting cells from PA-inducedmore » lipotoxicity. The Nrf2-Keap1 pathway is essential for the protection of cells from oxidative stress. p62 enhances its binding to Keap1 and leads to Nrf2 activation. Here, we show that PA potentiates Keap1 degradation and thereby activates the transcription of Nrf2 target genes partially through autophagy. Furthermore, this PA-mediated Keap1 degradation depends on p62. Correspondingly, a lack of p62 attenuates the PA-mediated Nrf2 activation and increases the susceptibility of cells to oxidative stress. These results indicate that p62 plays an important role in protecting cells against lipotoxicity through Keap1 degradation-mediated Nrf2 activation. - Highlights: • PA induces Keap1 downregulation and activates Nrf2 target gene transcription. • PA-induced Keap1 degradation is partly mediated by the autophagic pathway. • PA-induced Keap1 degradation depends on p62. • Ablation of p62 exacerbates PA-mediated apoptotic cell death.« less

  9. Bardoxolone methyl (BARD) ameliorates aristolochic acid (AA)-induced acute kidney injury through Nrf2 pathway.

    PubMed

    Wu, Juan; Liu, Xinhui; Fan, Jinjin; Chen, Wenfang; Wang, Juan; Zeng, Youjia; Feng, Xiaorang; Yu, Xueqing; Yang, Xiao

    2014-04-06

    Bardoxolone methyl (BARD) is an antioxidant modulator that acts through induction of the nuclear factor erythroid 2-related factor 2 (Nrf2) signaling pathway. This study aimed to investigate the role of BARD in protecting kidneys from aristolochic acid (AA)-induced acute kidney injury (AKI). Male C57BL/6 mice received intraperitoneal (i.p.) injections of aristolochic acid I (AAI) (5mg/kg/day) for 5 days to produce acute AA nephropathy (AAN) model. BARD (10mg/kg/day, i.p.) was applied for 7 consecutive days, starting 2 days prior to AAI administration. The mice in the AA group showed AKI as evidenced by worsening kidney function evaluated by blood urea nitrogen (BUN) and serum creatinine (SCr) levels, and severe tubulointerstitial injury marked by massive tubule necrosis in kidney tissues. BARD significantly reduced BUN and SCr levels which were elevated by AAI. Additionally, AAI-induced histopathological renal damage was ameliorated by BARD. Furthermore, the expression of Nrf2 was reduced, and its repressor Kelch-like ECH-associated protein 1 (Keap1) was increased significantly, whereas heme oxygenase-1 (HO-1) was upregulated and NAD(P)H quinone oxidoreductase-1 (NQO1) was barely increased in the cytoplasm of tubules in kidneys after treatment with AAI. BARD significantly upregulated renal Nrf2, NQO1 and HO-1 expression and downregulated Keap1 expression compared with those in the AA group. Moreover, it was found that Nrf2 was expressed both in the cytoplasm and nuclear of glomeruli and tubules, whereas NQO1 and HO-1 were localized in the cytoplasm of tubules only. In conclusion, AA-induced acute renal injury was associated with impaired Nrf2 activation and expression of its downstream target genes in renal tissues. BARD prevented renal damage induced by AAI, and this renoprotective effect may be exerted by activating the Nrf2 signaling pathway and increasing expression of the downstream target genes. Copyright © 2014 Elsevier Ireland Ltd. All rights reserved.

  10. Berberine, a natural antidiabetes drug, attenuates glucose neurotoxicity and promotes Nrf2-related neurite outgrowth

    DOE Office of Scientific and Technical Information (OSTI.GOV)

    Hsu, Ya-Yun; Graduate Institute of Medicine, College of Medicine, Kaohsiung Medical University, Kaohsiung 80708, Taiwan; Tseng, Yu-Ting

    Reactive oxygen intermediates production and apoptotic damage induced by high glucose are major causes of neuronal damage in diabetic neuropathy. Berberine (BBR), a natural antidiabetes drug with PI3K-activating activity, holds promise for diabetes because of its dual antioxidant and anti-apoptotic activities. We have previously reported that BBR attenuated H{sub 2}O{sub 2} neurotoxicity via activating the PI3K/Akt/Nrf2-dependent pathway. In this study, we further explored the novel protective mechanism of BBR on high glucose-induced apoptotic death and neurite damage of SH-SY5Y cells. Results indicated BBR (0.1–10 nM) significantly attenuated reactive oxygen species (ROS) production, nucleus condensation, and apoptotic death in high glucose-treatedmore » cells. However, AG1024, an inhibitor of insulin growth factor-1 (IGF-1) receptor, significantly abolished BBR protection against high glucose-induced neuronal death. BBR also increased Bcl-2 expression and decreased cytochrome c release. High glucose down-regulated IGF-1 receptor and phosphorylation of Akt and GSK-3β, the effects of which were attenuated by BBR treatment. BBR also activated nuclear erythroid 2-related factor 2 (Nrf2), the key antioxidative transcription factor, which is accompanied with up-regulation of hemeoxygenase-1 (HO-1). Furthermore, BBR markedly enhanced nerve growth factor (NGF) expression and promoted neurite outgrowth in high glucose-treated cells. To further determine the role of the Nrf2 in BBR neuroprotection, RNA interference directed against Nrf2 was used. Results indicated Nrf2 siRNA abolished BBR-induced HO-1, NGF, neurite outgrowth and ROS decrease. In conclusion, BBR attenuated high glucose-induced neurotoxicity, and we are the first to reveal this novel mechanism of BBR as an Nrf2 activator against glucose neurotoxicity, providing another potential therapeutic use of BBR on the treatment of diabetic complications. - Highlights: • BBR attenuates high glucose-induced ROS

  11. Astaxanthin Induces the Nrf2/HO-1 Antioxidant Pathway in Human Umbilical Vein Endothelial Cells by Generating Trace Amounts of ROS.

    PubMed

    Niu, Tingting; Xuan, Rongrong; Jiang, Ligang; Wu, Wei; Zhen, Zhanghe; Song, Yuling; Hong, Lili; Zheng, Kaiqin; Zhang, Jiaxing; Xu, Qingshan; Tan, Yinghong; Yan, Xiaojun; Chen, Haimin

    2018-02-14

    Astaxanthin is a powerful antioxidant that possesses potent protective effects against various human diseases and physiological disorders. However, the mechanisms underlying its antioxidant functions in cells are not fully understood. In the present study, the effects of astaxanthin on reactive oxygen species (ROS) production and antioxidant enzyme activity, as well as mitogen-activated protein kinases (MAPKs), phosphatidylinositol 3-kinase (PI3K)/Akt, and the nuclear factor erythroid 2-related factor 2 (Nrf-2)/heme oxygenase-1 (HO-1) pathways in human umbilical vein endothelial cells (HUVECs), were examined. It was shown that astaxanthin (0.1, 1, and 10 μM) induced ROS production by 9.35%, 14.8%, and 18.06% compared to control, respectively, in HUVECs. In addition, astaxanthin increased the mRNA levels of phase II enzymes HO-1 and also promoted GSH-Px enzyme activity. Furthermore, we observed ERK phosphorylation, nuclear translocation of Nrf-2, and activation of antioxidant response element-driven luciferase activity upon astaxanthin treatment. Knockdown of Nrf-2 by small interfering RNA inhibited HO-1 mRNA expression by 60%, indicating that the Nrf-2/ARE signaling pathway is activated by astaxanthin. Our results suggest that astaxanthin activates the Nrf-2/HO-1 antioxidant pathway by generating small amounts of ROS.

  12. Nrf2-Dependent Induction of NQO1 in Mouse Aortic Endothelial Cells Overexpressing Catalase

    PubMed Central

    Lin, Xinghua; Yang, Hong; Zhou, LiChun; Guo, ZhongMao

    2011-01-01

    Overexpression of catalase has been shown to accelerate benzo(a)pyrene (BaP) detoxification in mouse aortic endothelial cells (MAECs ). NAD(P)H:quinone oxidoreductase1 (NQO1) is an enzyme that catalyzes BaP-quinone detoxification. Aryl hydrocarbon receptor (AhR) and nuclear factor erythroid 2-related factor-2 (Nrf2) are transcription factors that control NQO1 expression. Here, we investigated the effect of catalase overexpression on NQO1, Nrf2 and AhR expressions. The levels of NQO1 mRNA and protein were comparable in MAECs isolated from wild-type and transgenic mice that overexpress human catalase (hCatTg). BaP treatment increased NQO1 mRNA and protein levels in both groups, with a significantly greater induction in hCatTg MAECs than in wild-type cells. BaP-induced NQO1 promoter activity was dramatically higher in hCatTg MAECs than in wild-type cells. Our data also showed that the basal level of AhR and the BaP-induced level of Nrf2 were significantly higher in hCatTg MAECs than in wild-type cells. Inhibition of specificity protein-1 (Sp1) binding to the AhR promoter region by mithramycin A reversed the enhanced effect of catalase overexpression on AhR expression. Knockdown of AhR by RNA interference diminished BaP-induced expression of Nrf2 and NQO1. Knockdown of Nrf2 significantly decreased NQO1 mRNA and protein levels in cells with or without BaP treatment. NQO1 promoter activity was abrogated by mutation of the Nrf2-binding site in this promoter. In contrast, mutation of the AhR-binding site in NQO1 promoter did not affect the promoter activity. These results suggest that catalase overexpression upregulates BaP-induced NQO1 expression via enhancing the Sp1-AhR-Nrf2 signaling cascade. PMID:21569840

  13. Regulatory Nexus of Synthesis and Degradation Deciphers Cellular Nrf2 Expression Levels

    PubMed Central

    Suzuki, Takafumi; Shibata, Tatsuhiro; Takaya, Kai; Shiraishi, Kouya; Kohno, Takashi; Kunitoh, Hideo; Tsuta, Koji; Furuta, Koh; Goto, Koichi; Hosoda, Fumie; Sakamoto, Hiromi; Motohashi, Hozumi

    2013-01-01

    Transcription factor Nrf2 (NF-E2-related factor 2) is essential for oxidative and electrophilic stress responses. While it has been well characterized that Nrf2 activity is tightly regulated at the protein level through proteasomal degradation via Keap1 (Kelch-like ECH-associated protein 1)-mediated ubiquitination, not much attention has been paid to the supply side of Nrf2, especially regulation of Nrf2 gene transcription. Here we report that manipulation of Nrf2 transcription is effective in changing the final Nrf2 protein level and activity of cellular defense against oxidative stress even in the presence of Keap1 and under efficient Nrf2 degradation, determined using genetically engineered mouse models. In excellent agreement with this finding, we found that minor A/A homozygotes of a single nucleotide polymorphism (SNP) in the human NRF2 upstream promoter region (rs6721961) exhibited significantly diminished NRF2 gene expression and, consequently, an increased risk of lung cancer, especially those who had ever smoked. Our results support the notion that in addition to control over proteasomal degradation and derepression from degradation/repression, the transcriptional level of the Nrf2 gene acts as another important regulatory point to define cellular Nrf2 levels. These results thus verify the critical importance of human SNPs that influence the levels of transcription of the NRF2 gene for future personalized medicine. PMID:23572560

  14. Inhibition of 12/15-LO ameliorates CVB3-induced myocarditis by activating Nrf2.

    PubMed

    Ai, Feng; Zheng, Jiayong; Zhang, Yanwei; Fan, Taibing

    2017-06-25

    Cardiac 12/15-lipoxygenase (12/15-LO) was reported to be markedly up-regulated and involved in the development of heart failure. Nuclear factor E2-related factor 2 (Nrf2) plays anti-inflammatory and anti-oxidation roles in response to oxidative stress. However, the role of 12/15-LO in viral myocarditis (VMC) and its underlying molecular mechanism have not yet been elucidated. Here, we demonstrated that 12/15-LO was up-regulated and Nrf2 was down-regulated in coxsackievirus B3 (CVB3)-infected mice and cardiac myocytes. Baicalein, the specific inhibitor of 12/15-LO, was employed to investigate the role of 12/15-LO and its underlying mechanism in VMC. We found that baicalein treatment alleviated CVB3-induced VMC mouse models, as demonstrated by less inflammatory lesions in the heart tissues and less CK-MB level. Moreover, baicalein treatment attenuated CVB3-induced inflammatory cytokine production and oxidative stress. Mechanistic analysis suggested that baicalein treatment relieved CVB3-induced reduction of Nrf2 and heme oxygenase-1 (HO-1) expressions. Taken together, our study indicated that inhibition of 12/15-LO ameliorates VMC by activating Nrf2, providing a new therapeutic strategy for the therapy of VMC. Copyright © 2017 Elsevier B.V. All rights reserved.

  15. Prolonged fasting activates Nrf2 in post-weaned elephant seals

    PubMed Central

    Vázquez-Medina, José Pablo; Soñanez-Organis, José G.; Rodriguez, Ruben; Viscarra, Jose A.; Nishiyama, Akira; Crocker, Daniel E.; Ortiz, Rudy M.

    2013-01-01

    SUMMARY Elephant seals naturally experience prolonged periods of absolute food and water deprivation (fasting). In humans, rats and mice, prolonged food deprivation activates the renin–angiotensin system (RAS) and increases oxidative damage. In elephant seals, prolonged fasting activates RAS without increasing oxidative damage likely due to an increase in antioxidant defenses. The mechanism leading to the upregulation of antioxidant defenses during prolonged fasting remains elusive. Therefore, we investigated whether prolonged fasting activates the redox-sensitive transcription factor Nrf2, which controls the expression of antioxidant genes, and if such activation is potentially mediated by systemic increases in RAS. Blood and skeletal muscle samples were collected from seals fasting for 1, 3, 5 and 7 weeks. Nrf2 activity and nuclear content increased by 76% and 167% at week 7. Plasma angiotensin II (Ang II) and transforming growth factor β (TGF-β) were 5000% and 250% higher at week 7 than at week 1. Phosphorylation of Smad2, an effector of Ang II and TGF signaling, increased by 120% at week 7 and by 84% in response to intravenously infused Ang II. NADPH oxidase 4 (Nox4) mRNA expression, which is controlled by smad proteins, increased 430% at week 7, while Nox4 protein expression, which can activate Nrf2, was 170% higher at week 7 than at week 1. These results demonstrate that prolonged fasting activates Nrf2 in elephant seals and that RAS stimulation can potentially result in increased Nox4 through Smad phosphorylation. The results also suggest that Nox4 is essential to sustain the hormetic adaptive response to oxidative stress in fasting seals. PMID:23619404

  16. Prolonged fasting activates Nrf2 in post-weaned elephant seals.

    PubMed

    Vázquez-Medina, José Pablo; Soñanez-Organis, José G; Rodriguez, Ruben; Viscarra, Jose A; Nishiyama, Akira; Crocker, Daniel E; Ortiz, Rudy M

    2013-08-01

    Elephant seals naturally experience prolonged periods of absolute food and water deprivation (fasting). In humans, rats and mice, prolonged food deprivation activates the renin-angiotensin system (RAS) and increases oxidative damage. In elephant seals, prolonged fasting activates RAS without increasing oxidative damage likely due to an increase in antioxidant defenses. The mechanism leading to the upregulation of antioxidant defenses during prolonged fasting remains elusive. Therefore, we investigated whether prolonged fasting activates the redox-sensitive transcription factor Nrf2, which controls the expression of antioxidant genes, and if such activation is potentially mediated by systemic increases in RAS. Blood and skeletal muscle samples were collected from seals fasting for 1, 3, 5 and 7 weeks. Nrf2 activity and nuclear content increased by 76% and 167% at week 7. Plasma angiotensin II (Ang II) and transforming growth factor β (TGF-β) were 5000% and 250% higher at week 7 than at week 1. Phosphorylation of Smad2, an effector of Ang II and TGF signaling, increased by 120% at week 7 and by 84% in response to intravenously infused Ang II. NADPH oxidase 4 (Nox4) mRNA expression, which is controlled by smad proteins, increased 430% at week 7, while Nox4 protein expression, which can activate Nrf2, was 170% higher at week 7 than at week 1. These results demonstrate that prolonged fasting activates Nrf2 in elephant seals and that RAS stimulation can potentially result in increased Nox4 through Smad phosphorylation. The results also suggest that Nox4 is essential to sustain the hormetic adaptive response to oxidative stress in fasting seals.

  17. MHY1485 ameliorates UV-induced skin cell damages via activating mTOR-Nrf2 signaling

    PubMed Central

    Yang, Bo; Xu, Qiu-Yun; Guo, Chun-Yan; Huang, Jin-Wen; Wang, Shu-Mei; Li, Yong-Mei; Tu, Ying; He, Li; Bi, Zhi-Gang; Ji, Chao; Cheng, Bo

    2017-01-01

    Ultra Violet (UV)-caused skin cell damage is a main cause of skin cancer. Here, we studied the activity of MHY1485, a mTOR activator, in UV-treated skin cells. In primary human skin keratinocytes, HaCaT keratinocytes and human skin fibroblasts, MHY1485 ameliorated UV-induced cell death and apoptosis. mTOR activation is required for MHY1485-induced above cytoprotective actions. mTOR kinase inhibitors (OSI-027, AZD-8055 and AZD-2014) or mTOR shRNA knockdown almost abolished MHY1485-induced cytoprotection. Further, MHY1485 treatment in skin cells activated mTOR downstream NF-E2-related factor 2 (Nrf2) signaling, causing Nrf2 Ser-40 phosphorylation, stabilization/upregulation and nuclear translocation, as well as mRNA expression of Nrf2-dictated genes. Contrarily, Nrf2 knockdown or S40T mutation almost nullified MHY1485-induced cytoprotection. MHY1485 suppressed UV-induced reactive oxygen species production and DNA single strand breaks in skin keratinocytes and fibroblasts. Together, we conclude that MHY1485 inhibits UV-induced skin cell damages via activating mTOR-Nrf2 signaling. PMID:28061443

  18. Activation of Nrf2 is required for up-regulation of the π class of glutathione S-transferase in rat primary hepatocytes with L-methionine starvation.

    PubMed

    Lin, Ai-Hsuan; Chen, Haw-Wen; Liu, Cheng-Tze; Tsai, Chia-Wen; Lii, Chong-Kuei

    2012-07-04

    Numerous genes expression is regulated in response to amino acid shortage, which helps organisms adapt to amino acid limitation. The expression of the π class of glutathione (GSH) S-transferase (GSTP), a highly inducible phase II detoxification enzyme, is regulated mainly by activates activating protein 1 (AP-1) binding to the enhancer I of GSTP (GPEI). Here we show the critical role of nuclear factor erythroid-2-related factor 2 (Nrf2) in up-regulating GSTP gene transcription. Primary rat hepatocytes were cultured in a methionine-restricted medium, and immunoblotting and RT-PCR analyses showed that methionine restriction time-dependently increased GSTP protein and mRNA expression over a 48 h period. Nrf2 translocation to the nucleus, nuclear proteins binding to GPEI, and antioxidant response element (ARE) luciferase reporter activity were increased by methionine restriction as well as by l-buthionine sulfoximine (BSO), a GSH synthesis inhibitor. Transfection with Nrf2 siRNA knocked down Nrf2 expression and reversed the methionine-induced GSTP expression and GPEI binding activity. Chromatin immunoprecipitation assay confirmed the binding of Nrf2 to the GPEI. Phosphorylation of extracellular signal-regulated kinase 2 (ERK2) was increased in methionine-restricted and BSO-treated cells. ERK2 siRNA abolished methionine restriction-induced Nrf2 nuclear translocation, GPEI binding activity, ARE-luciferase reporter activity, and GSTP expression. Our results suggest that the up-regulation of GSTP gene transcription in response to methionine restriction likely occurs via the ERK-Nrf2-GPEI signaling pathway.

  19. Rosmarinic acid counteracts activation of hepatic stellate cells via inhibiting the ROS-dependent MMP-2 activity: Involvement of Nrf2 antioxidant system

    DOE Office of Scientific and Technical Information (OSTI.GOV)

    Lu, Changfang; Zou, Yu; Liu, Yuzhang

    Recently, oxidative stress is involved in hepatofibrogenesis. Matrix metalloproteinase-2 (MMP-2) is required for activation of hepatic stellate cells (HSCs) in response to reactive oxygen species (ROS). This study was designed to explore the hypothesis that the inhibitory effect of rosmarinic acid (RA) on HSCs activation might mainly result from its antioxidant capability by increasing the synthesis of glutathione (GSH) involved in nuclear factor kappa B (NF-κB)-dependent inhibition of MMP-2 activity. Here, we demonstrate that RA reverses activated HSCs to quiescent cells. Concomitantly, RA inhibits MMP-2 activity. RNA interference-imposed knockdown of NF-κB abolished down-regulation of MMP-2 by RA. RA-mediated inactivation ofmore » NF-κB could be blocked by the diphenyleneiodonium chloride (DPI; a ROS inhibitor). Conversely, transfection of dominant-negative (DN) mutant of extracellular signal-regulated kinases 2 (ERK2), c-Jun N-terminal kinase 1 (JNK1), or p38α kinase had no such effect. Simultaneously, RA suppresses ROS generation and lipid peroxidation (LPO) whereas increases cellular GSH in HSC-T6 cells. Furthermore, RA significantly increased antioxidant response element (ARE)-mediated luciferase activity, nuclear translocation of nuclear factor erythroid 2-related factor 2 (Nrf2) and catalytic subunits from glutamate cysteine ligase (GCLc) expression, but not modulatory subunits from GCL (GCLm). RA-mediated up-regulation of GClc is inhibited by the shRNA-induced Nrf2 knockdown. The knocking down of Nrf2 or buthionine sulfoximine (a GCL inhibitor) abolished RA-mediated inhibition of ROS. Collectively, these results provide novel insights into the mechanisms of RA as an antifibrogenic candidate in the prevention and treatment of liver fibrosis. - Highlights: • RA reverses activated HSCs to quiescent cells. • RA suppresses MMP-2 activity through a NF-κB-dependent pathway. • Inhibition of oxidative stress by RA is dependent on nuclear translocation

  20. Metallothionein plays a prominent role in the prevention of diabetic nephropathy by sulforaphane via up-regulation of Nrf2

    PubMed Central

    Wu, Hao; Kong, Lili; Cheng, Yanli; Zhang, Zhiguo; Wang, Yangwei; Lou, Manyu; Tan, Yi; Chen, Xiangmei; Miao, Lining; Cai, Lu

    2015-01-01

    Sulforaphane (SFN) prevents diabetic nephropathy (DN) in type 1 diabetes via up-regulation of nuclear factor (erythroid-derived 2)-like 2 (Nrf2). However, it has not been addressed whether SFN also prevents DN from type 2 diabetes or which Nrf2 downstream gene(s) play(s) the key role in SFN renal protection. Here we investigated whether Nrf2 is required for SFN protection against type 2 diabetes-induced DN and whether metallothionein (MT) is an Nrf2 downstream antioxidant using Nrf2 knockout (Nrf2-null) mice. In addition, MT knockout mice were used to further verify if MT is indispensable for SFN protection against DN. Diabetes-increased albuminuria, renal fibrosis, and inflammation were significantly prevented by SFN, and Nrf2 and MT expression was increased. However, SFN renal protection was completely lost in Nrf2-null diabetic mice, confirming the pivotal role of Nrf2 in SFN protection from type 2 diabetes-induced DN. Moreover, SFN failed to up-regulate MT in the absence of Nrf2, suggesting that MT is an Nrf2 downstream antioxidant. MT deletion resulted in a partial, but significant attenuation of SFN renal protection from type 2 diabetes, demonstrating a partial requirement for MT for SFN renal protection. Therefore, the present study demonstrates for the first time that as an Nrf2 downstream antioxidant, MT plays an important, though partial, role in mediating SFN renal protection from type 2 diabetes. PMID:26415026

  1. Metallothionein plays a prominent role in the prevention of diabetic nephropathy by sulforaphane via up-regulation of Nrf2.

    PubMed

    Wu, Hao; Kong, Lili; Cheng, Yanli; Zhang, Zhiguo; Wang, Yangwei; Luo, Manyu; Tan, Yi; Chen, Xiangmei; Miao, Lining; Cai, Lu

    2015-12-01

    Sulforaphane (SFN) prevents diabetic nephropathy (DN) in type 1 diabetes via up-regulation of nuclear factor (erythroid-derived 2)-like 2 (Nrf2). However, it has not been addressed whether SFN also prevents DN from type 2 diabetes or which Nrf2 downstream gene(s) play(s) the key role in SFN renal protection. Here we investigated whether Nrf2 is required for SFN protection against type 2 diabetes-induced DN and whether metallothionein (MT) is an Nrf2 downstream antioxidant using Nrf2 knockout (Nrf2-null) mice. In addition, MT knockout mice were used to further verify if MT is indispensable for SFN protection against DN. Diabetes-increased albuminuria, renal fibrosis, and inflammation were significantly prevented by SFN, and Nrf2 and MT expression was increased. However, SFN renal protection was completely lost in Nrf2-null diabetic mice, confirming the pivotal role of Nrf2 in SFN protection from type 2 diabetes-induced DN. Moreover, SFN failed to up-regulate MT in the absence of Nrf2, suggesting that MT is an Nrf2 downstream antioxidant. MT deletion resulted in a partial, but significant attenuation of SFN renal protection from type 2 diabetes, demonstrating a partial requirement for MT for SFN renal protection. Therefore, the present study demonstrates for the first time that as an Nrf2 downstream antioxidant, MT plays an important, though partial, role in mediating SFN renal protection from type 2 diabetes. Copyright © 2015 Elsevier Inc. All rights reserved.

  2. Alteration of Nrf2 and Glutamate Cysteine Ligase expression contribute to lesions growth and fibrogenesis in ectopic endometriosis.

    PubMed

    Marcellin, L; Santulli, P; Chouzenoux, S; Cerles, O; Nicco, C; Dousset, B; Pallardy, M; Kerdine-Römer, S; Just, P A; Chapron, C; Batteux, F

    2017-09-01

    The redox-sensitive nuclear factor erythroid-derived 2-like 2 (NRF2) controls endogenous antioxidant enzymes' transcription and protects against oxidative damage which is triggered by inflammation and known to favor progression of endometriosis. Glutamate Cysteine Ligase (GCL), a target gene of NRF2, is the first enzyme in the synthesis cascade of glutathione, an important endogenous antioxidant. Sixty-one patients, with thorough surgical examination of the abdominopelvic cavity, were recruited for the study: 31 with histologically-proven endometriosis and 30 disease-free women taken as controls. Expressions of NRF2 and GCL were investigated by quantitative RT-PCR and immunohistochemistry in eutopic and ectopic endometria from endometriosis-affected women and in endometrium of disease-free women. Ex vivo stromal and epithelial cells were extracted and purified from endometrial and endometriotic biopsies to explore expression of NRF2 and GCL in both stromal and epithelial compartments by western blot. Finally, in order to strengthen the role of NRF2 in endometriosis pathogenesis, we evaluated the drop of NRF2 expression in a mouse model of endometriosis using NRF2 knockout (NRF2 -/- ) mice. The mRNA levels of NRF2 and GCL were significantly lower in ectopic endometria of endometriosis-affected women compared to eutopic endometria of disease-free women. The immunohistochemical analysis confirmed the decreased expression of both NRF2 and GCL in ectopic endometriotic tissues compared to eutopic endometria of endometriosis-affected and disease-free women. Immunoblotting revealed a significant decreased of NRF2 and GCL expression in epithelial and stroma cells from ectopic lesions of endometriosis-affected women compared to eutopic endometria from controls. Using a murine model of endometriosis, NRF2 -/- implants were more fibrotic compared to wild-type with an increased weight and volume. These findings indicate that expression of the transcription factor NRF2 and its

  3. The redox-sensing gene Nrf2 affects intestinal homeostasis, insecticide resistance, and Zika virus susceptibility in the mosquito Aedes aegypti.

    PubMed

    Bottino-Rojas, Vanessa; Talyuli, Octavio A C; Carrara, Luana; Martins, Ademir J; James, Anthony A; Oliveira, Pedro L; Paiva-Silva, Gabriela O

    2018-06-08

    Production and degradation of reactive oxygen species (ROS) are extensively regulated to ensure proper cellular responses to various environmental stimuli and stresses. Moreover, physiologically generated ROS function as secondary messengers that can influence tissue homeostasis. The cap'n'collar transcription factor known as nuclear factor erythroid-derived factor 2 (Nrf2) coordinates an evolutionarily conserved transcriptional activation pathway that mediates antioxidant and detoxification responses in many animal species, including insects and mammals. Here, we show that Nrf2-mediated signaling affects embryo survival, midgut homeostasis, and redox biology in Aedes aegypti , a mosquito species vector of dengue, Zika, and other disease-causing viruses. We observed that AeNrf2 silencing increases ROS levels and stimulates intestinal stem cell proliferation. Because ROS production is a major aspect of innate immunity in mosquito gut, we found that a decrease in Nrf2 signaling results in reduced microbiota growth and Zika virus infection. Moreover, we provide evidence that AeNrf2 signaling also controls transcriptional adaptation of A. aegypti to insecticide challenge. Therefore, we conclude that Nrf2-mediated response regulates assorted gene clusters in A. aegypti that determine cellular and midgut redox balance, affecting overall xenobiotic resistance and vectorial adaptation of the mosquito. © 2018 by The American Society for Biochemistry and Molecular Biology, Inc.

  4. Melatonin attenuates memory impairment induced by Klotho gene deficiency via interactive signaling between MT2 receptor, ERK, and Nrf2-related antioxidant potential.

    PubMed

    Shin, Eun-Joo; Chung, Yoon Hee; Le, Hoang-Lan Thi; Jeong, Ji Hoon; Dang, Duy-Khanh; Nam, Yunsung; Wie, Myung Bok; Nah, Seung-Yeol; Nabeshima, Yo-Ichi; Nabeshima, Toshitaka; Kim, Hyoung-Chun

    2014-12-30

    We demonstrated that oxidative stress plays a crucial role in cognitive impairment in klotho mutant mice, a genetic model of aging. Since down-regulation of melatonin due to aging is well documented, we used this genetic model to determine whether the antioxidant property of melatonin affects memory impairment. First, we examined the effects of melatonin on hippocampal oxidative parameters and the glutathione/oxidized glutathione (GSH/GSSG) ratio and memory dysfunction of klotho mutant mice. Second, we investigated whether a specific melatonin receptor is involved in the melatonin-mediated pharmacological response by application with melatonin receptor antagonists. Third, we examined phospho-extracellular-signal-regulated kinase (ERK) expression, nuclear factor erythroid 2-related factor 2 (Nrf2) nuclear translocation, Nrf2 DNA binding activity, and glutamate-cysteine ligase (GCL) mRNA expression. Finally, we examined effects of the ERK inhibitor SL327 in response to antioxidant efficacy and memory enhancement mediated by melatonin. Treatment with melatonin resulted in significant attenuations of oxidative damage, a decrease in the GSH/GSSG ratio, and a significant amelioration of memory impairment in this aging model. These effects of melatonin were significantly counteracted by the selective MT2 receptor antagonist 4-P-PDOT. Importantly, 4-P-PDOT or SL327 also counteracted melatonin-mediated attenuation in response to the decreases in phospho-ERK expression, Nrf2 nuclear translocation, Nrf2 DNA-binding activity, and GCL mRNA expression in the hippocampi of klotho mutant mice. SL327 also counteracted the up-regulation of the GSH/GSSG ratio and the memory enhancement mediated by melatonin in klotho mutant mice. Melatonin attenuates oxidative stress and the associated memory impairment induced by klotho deficiency via signaling interaction between the MT2 receptor and ERK- and Nrf2-related antioxidant potential. © The Author 2015. Published by Oxford University

  5. Melatonin Attenuates Memory Impairment Induced by Klotho Gene Deficiency Via Interactive Signaling Between MT2 Receptor, ERK, and Nrf2-Related Antioxidant Potential

    PubMed Central

    Shin, Eun-Joo; Chung, Yoon Hee; Le, Hoang-Lan Thi; Jeong, Ji Hoon; Dang, Duy-Khanh; Nam, Yunsung; Wie, Myung Bok; Nah, Seung-Yeol; Nabeshima, Yo-Ichi; Nabeshima, Toshitaka; Kim, Hyoung-Chun

    2015-01-01

    Background: We demonstrated that oxidative stress plays a crucial role in cognitive impairment in klotho mutant mice, a genetic model of aging. Since down-regulation of melatonin due to aging is well documented, we used this genetic model to determine whether the antioxidant property of melatonin affects memory impairment. Methods: First, we examined the effects of melatonin on hippocampal oxidative parameters and the glutathione/oxidized glutathione (GSH/GSSG) ratio and memory dysfunction of klotho mutant mice. Second, we investigated whether a specific melatonin receptor is involved in the melatonin-mediated pharmacological response by application with melatonin receptor antagonists. Third, we examined phospho-extracellular-signal-regulated kinase (ERK) expression, nuclear factor erythroid 2-related factor 2 (Nrf2) nuclear translocation, Nrf2 DNA binding activity, and glutamate-cysteine ligase (GCL) mRNA expression. Finally, we examined effects of the ERK inhibitor SL327 in response to antioxidant efficacy and memory enhancement mediated by melatonin. Results: Treatment with melatonin resulted in significant attenuations of oxidative damage, a decrease in the GSH/GSSG ratio, and a significant amelioration of memory impairment in this aging model. These effects of melatonin were significantly counteracted by the selective MT2 receptor antagonist 4-P-PDOT. Importantly, 4-P-PDOT or SL327 also counteracted melatonin-mediated attenuation in response to the decreases in phospho-ERK expression, Nrf2 nuclear translocation, Nrf2 DNA-binding activity, and GCL mRNA expression in the hippocampi of klotho mutant mice. SL327 also counteracted the up-regulation of the GSH/GSSG ratio and the memory enhancement mediated by melatonin in klotho mutant mice. Conclusions: Melatonin attenuates oxidative stress and the associated memory impairment induced by klotho deficiency via signaling interaction between the MT2 receptor and ERK- and Nrf2-related antioxidant potential. PMID

  6. Nrf2 Knockdown Disrupts the Protective Effect of Curcumin on Alcohol-Induced Hepatocyte Necroptosis.

    PubMed

    Lu, Chunfeng; Xu, Wenxuan; Zhang, Feng; Shao, Jiangjuan; Zheng, Shizhong

    2016-12-05

    It has emerged that hepatocyte necroptosis plays a critical role in chronic alcoholic liver disease (ALD). Our previous study has identified that the beneficial therapeutic effect of curcumin on alcohol-caused liver injury might be attributed to activation of nuclear factor (erythroid-derived 2)-like 2 (Nrf2), whereas the role of curcumin in regulating necroptosis and the underlying mechanism remain to be determined. We first found that chronic alcohol consumption triggered obvious hepatocyte necroptosis, leading to increased expression of receptor-interacting protein 1, receptor-interacting protein 3, high-mobility group box 1, and phosphorylated mixed lineage kinase domain-like in murine livers. Curcumin dose-dependently ameliorated hepatocyte necroptosis and alleviated alcohol-caused decrease in hepatic Nrf2 expression in alcoholic mice. Then Nrf2 shRNA lentivirus was introduced to generate Nrf2-knockdown mice. Our results indicated that Nrf2 knockdown aggravated the effects of alcohol on liver injury and necroptosis and even abrogated the inhibitory effect of curcumin on necroptosis. Further, activated Nrf2 by curcumin inhibited p53 expression in both livers and cultured hepatocytes under alcohol stimulation. The next in vitro experiments, similar to in vivo ones, revealed that although Nrf2 knockdown abolished the suppression of curcumin on necroptosis of hepatocytes exposed to ethanol, p53 siRNA could clearly rescued the relative effect of curcumin. In summary, for the first time, we concluded that curcumin attenuated alcohol-induced hepatocyte necroptosis in a Nrf2/p53-dependent mechanism. These findings make curcumin an excellent candidate for ALD treatment and advance the understanding of ALD mechanisms associated with hepatocyte necroptosis.

  7. The nuclear factor (erythroid-derived 2)-like 2 (Nrf2) activator dh404 protects against diabetes-induced endothelial dysfunction.

    PubMed

    Sharma, Arpeeta; Rizky, Luddwi; Stefanovic, Nada; Tate, Mitchel; Ritchie, Rebecca H; Ward, Keith W; de Haan, Judy B

    2017-03-03

    Vascular dysfunction is a pivotal event in the development of diabetes-associated vascular disease. Increased inflammation and oxidative stress are major contributors to vascular dysfunction. Nrf2, a master regulator of several anti-oxidant genes and a suppressor of inflammatory NF-κB, has potential as a target to combat oxidative stress and inflammation. The aim of this study was to investigate the effects of a novel Nrf2 activator, the bardoxolone methyl derivative dh404, on endothelial function in vitro and in vivo. dh404 at 3 mg/kg was administered to male Akita mice, an established diabetic mouse model of insulin insufficiency and hyperglycemia, from 6 weeks of age. At 26 weeks of age, vascular reactivity was assessed by wire myography, pro-inflammatory expression was assessed in the aortas by qRT-PCR and immunohistochemistry, and systemic and vascular oxidative stress measurements were determined. Additionally, studies in human aortic endothelial cells (HAECs) derived from normal and diabetic patients in the presence or absence of dh404 included assessment of pro-inflammatory genes by qRT-PCR and western blotting. Oxidative stress was assessed by three methods; L-012, DCFDA and amplex red. Static adhesion assays were performed to determine the leukocyte-endothelial interaction in the presence or absence of dh404. Dh404 significantly attenuated endothelial dysfunction in diabetic Akita mice characterized by reduced contraction in response to phenylephrine and the downregulation of inflammatory genes (VCAM-1, ICAM-1, p65, IL-1β) and pro-oxidant genes (Nox1 and Nox2). Furthermore, reduced systemic and vascular oxidative stress levels were observed in diabetic Akita mice. dh404 exhibited cytoprotective effects in diabetic HAECs in vitro, reflected by significant upregulation of Nrf2-responsive genes, NAD(P)H quinone oxidoreductase 1 (NQO1) and heme oxygenase-1 (HO-1), reduction of oxidative stress markers (O 2 ·- and H 2 O 2 ), inhibition of inflammatory

  8. Activation of the Nrf2-ARE pathway by siRNA knockdown of Keap1 reduces oxidative stress and provides partial protection from MPTP-mediated neurotoxicity.

    PubMed

    Williamson, Tracy P; Johnson, Delinda A; Johnson, Jeffrey A

    2012-06-01

    Nuclear factor erythroid 2-related factor 2 (Nrf2) is a transcription factor that binds to the antioxidant response element, a cis-acting regulatory element that increases expression of detoxifying enzymes and antioxidant proteins. Kelch-like ECH associating protein 1 (Keap1) protein is a negative regulator of Nrf2. Previous work has shown that genetic overexpression of Nrf2 is protective in vitro and in vivo. To modulate the Nrf2-ARE system without overexpressing Nrf2, we used short interfering RNA (siRNA) directed against Keap1. Keap1 siRNA administration in primary astrocytes increased the levels of Nrf2-ARE driven genes and protected against oxidative stress. Moreover, Keap1 siRNA resulted in a persistent upregulation of the Nrf2-ARE pathway and protection against oxidative stress in primary astrocytes. Keap1 siRNA injected into the striatum was also modestly protective against MPTP-induced dopaminergic terminal damage. These data indicate that activation of endogenous intracellular levels of Nrf2 is sufficient to protect in models of oxidative stress and Parkinson's disease. Copyright © 2012 Elsevier Inc. All rights reserved.

  9. Reversal of cigarette smoke extract-induced sinonasal epithelial cell barrier dysfunction through Nrf2 Activation.

    PubMed

    Tharakan, Anuj; Halderman, Ashleigh A; Lane, Andrew P; Biswal, Shyam; Ramanathan, Murugappan

    2016-11-01

    Environmental factors such as inhaled pollutants like cigarette smoke may play a significant role in diseases of the upper airway including chronic rhinosinusitis (CRS). Recent studies have shown that cigarette smoke causes impaired airway epithelial cell barrier function likely through environmental oxidative stress related pathways. The purpose of this study is to explore whether enhancing nuclear factor erythroid 2 [NF-E2]-related factor 2 [Nrf2], the body's master antioxidant system, can ameliorate cigarette smoke-induced sinonasal epithelial cell (SNEC) barrier dysfunction. Human SNECs (HSNECs) were grown from control patients at the air-liquid interface (ALI). HSNECs were stimulated with cigarette smoke extract (CSE) with and without pharmacologic activation of Nrf2. HSNECs were then stained for the epithelial cell junctional proteins zonula occludens 1 (ZO-1) and junctional adhesion molecule A (JAM-A) using confocal microscopy. In addition, transepithelial electrical resistance (TER) was measured in cultures before and after stimulation with CSE. CSE stimulation caused a global disruption of the epithelial junctional proteins ZO-1 and JAM-A along with an associated decrease in TER levels. Enhancing Nrf2 levels prior to stimulation with CSE was associated with increased localization of ZO-1 and JAM-A levels at the cell surface and statistically significant increases in TER levels. This is the first study to demonstrate that cigarette smoke induced SNEC barrier dysfunction is reversible by Nrf2 activation. The Nrf2 antioxidant pathway may represent a potential therapeutic target for cigarette smoke-associated sinonasal inflammation. © 2016 ARS-AAOA, LLC.

  10. Electrophilic nitro-fatty acids prevent astrocyte-mediated toxicity to motor neurons in a cell model of familial amyotrophic lateral sclerosis via nuclear factor erythroid 2-related factor activation.

    PubMed

    Diaz-Amarilla, Pablo; Miquel, Ernesto; Trostchansky, Andrés; Trias, Emiliano; Ferreira, Ana M; Freeman, Bruce A; Cassina, Patricia; Barbeito, Luis; Vargas, Marcelo R; Rubbo, Homero

    2016-06-01

    Nitro-fatty acids (NO2-FA) are electrophilic signaling mediators formed in tissues during inflammation, which are able to induce pleiotropic cytoprotective and antioxidant pathways including up regulation of Nuclear factor erythroid 2-related factor 2 (Nrf2) responsive genes. Amyotrophic Lateral Sclerosis (ALS) is a fatal neurodegenerative disease characterized by the loss of motor neurons associated to an inflammatory process that usually aggravates the disease progression. In ALS animal models, the activation of the transcription factor Nrf2 in astrocytes confers protection to neighboring neurons. It is currently unknown whether NO2-FA can exert protective activity in ALS through Nrf2 activation. Herein we demonstrate that nitro-arachidonic acid (NO2-AA) or nitro-oleic acid (NO2-OA) administrated to astrocytes expressing the ALS-linked hSOD1(G93A) induce antioxidant phase II enzyme expression through Nrf2 activation concomitant with increasing intracellular glutathione levels. Furthermore, treatment of hSOD1(G93A)-expressing astrocytes with NO2-FA prevented their toxicity to motor neurons. Transfection of siRNA targeted to Nrf2 mRNA supported the involvement of Nrf2 activation in NO2-FA-mediated protective effects. Our results show for the first time that NO2-FA induce a potent Nrf2-dependent antioxidant response in astrocytes capable of preventing motor neurons death in a culture model of ALS. Copyright © 2016 Elsevier Inc. All rights reserved.

  11. Inorganic Arsenic Induces NRF2-Regulated Antioxidant Defenses in Both Cerebral Cortex and Hippocampus in Vivo.

    PubMed

    Zhang, Yang; Duan, Xiaoxu; Li, Jinlong; Zhao, Shuo; Li, Wei; Zhao, Lu; Li, Wei; Nie, Huifang; Sun, Guifang; Li, Bing

    2016-08-01

    Inorganic arsenic is reported to induce the reactive oxygen species-mediated oxidative stress, which is supposed to be one of the main mechanisms of arsenic-related neurological diseases. Nuclear factor erythroid 2-related factor 2 (NRF2), a master regulator of antioxidant defense systems, up-regulates the expression of target genes to fight against oxidative damages caused by harmful substances, including metals. In the present study, mice were used as a model to investigate the oxidative stress levels and the expressions of NRF2-regulated antioxidant substances in both cerebral cortex and hippocampus with 5, 10 and 20 mg/kg NaAsO2 exposure intra-gastrically. Our results showed that acute NaAsO2 treatment resulted in decreased total anti-oxidative capacity (T-AOC) and increased maleic dialdehyde production in the nervous system. We also detected rapidly elevation of NRF2 protein levels by enhancement of Nrf2 transcription, especially at 20 mg/kg NaAsO2 exposure group. In the meantime, mRNA and protein levels of Nrf2 encoding antioxidant enzymes heme oxygenase-1 (HO-1), NAD(P)H: quinine oxidoreductase 1 (NQO1) and glutathione S-transferase (GST) were consistently elevated time- and dose-dependently both in the cerebral cortex and hippocampus. Taken together, the presence study demonstrated the activation of NRF2 pathway, an early antioxidant defensive response, in both cerebral cortex and hippocampus upon inorganic arsenic (iAs) exposure in vivo. A better knowledge on the roles of NRF2 pathway in maintaining cellular redox homeostasis would be helpful for the strategies on improvement of neurotoxicity related to this metalloid.

  12. Association of Nuclear Factor-Erythroid 2-Related Factor 2, Thioredoxin Interacting Protein, and Heme Oxygenase-1 Gene Polymorphisms with Diabetes and Obesity in Mexican Patients.

    PubMed

    Jiménez-Osorio, Angélica Saraí; González-Reyes, Susana; García-Niño, Wylly Ramsés; Moreno-Macías, Hortensia; Rodríguez-Arellano, Martha Eunice; Vargas-Alarcón, Gilberto; Zúñiga, Joaquín; Barquera, Rodrigo; Pedraza-Chaverri, José

    2016-01-01

    The nuclear factor-erythroid 2- (NF-E2-) related factor 2 (Nrf2) is abated and its ability to reduce oxidative stress is impaired in type 2 diabetes and obesity. Thus, the aim of this study was to explore if polymorphisms in Nrf2 and target genes are associated with diabetes and obesity in Mexican mestizo subjects. The rs1800566 of quinone oxidoreductase 1 (NQO1) gene, rs7211 of thioredoxin interacting protein (TXNIP) gene, rs2071749 of heme oxygenase-1 (HMOX1) gene, and the rs6721961 and the rs2364723 from Nrf2 gene were genotyped in 627 diabetic subjects and 1020 controls. The results showed that the rs7211 polymorphism is a protective factor against obesity in nondiabetic subjects (CC + CT versus TT, OR = 0.40, P = 0.005) and in women (CC versus CT + TT, OR = 0.7, P = 0.016). TT carriers had lower high-density lipoprotein cholesterol levels and lower body mass index. The rs2071749 was positively associated with obesity (AA versus AG + GG, OR = 1.25, P = 0.026). Finally, the rs6721961 was negatively associated with diabetes in men (CC versus CA + AA, OR = 0.62, P = 0.003). AA carriers showed lower glucose concentrations. No association was found for rs1800566 and rs2364723 polymorphisms. In conclusion, the presence of Nrf2 and related genes polymorphisms are associated with diabetes and obesity in Mexican patients.

  13. Marine Natural Product Honaucin A Attenuates Inflammation by Activating the Nrf2-ARE Pathway.

    PubMed

    Mascuch, Samantha J; Boudreau, Paul D; Carland, Tristan M; Pierce, N Tessa; Olson, Joshua; Hensler, Mary E; Choi, Hyukjae; Campanale, Joseph; Hamdoun, Amro; Nizet, Victor; Gerwick, William H; Gaasterland, Teresa; Gerwick, Lena

    2018-03-23

    The cyanobacterial marine natural product honaucin A inhibits mammalian innate inflammation in vitro and in vivo. To decipher its mechanism of action, RNA sequencing was used to evaluate differences in gene expression of cultured macrophages following honaucin A treatment. This analysis led to the hypothesis that honaucin A exerts its anti-inflammatory activity through activation of the cytoprotective nuclear erythroid 2-related factor 2 (Nrf2)-antioxidant response element/electrophile response element (ARE/EpRE) signaling pathway. Activation of this pathway by honaucin A in cultured human MCF7 cells was confirmed using an Nrf2 luciferase reporter assay. In vitro alkylation experiments with the natural product and N-acetyl-l-cysteine suggest that honaucin A activates this pathway through covalent interaction with the sulfhydryl residues of the cytosolic repressor protein Keap1. Honaucin A presents a potential therapeutic lead for diseases with an inflammatory component modulated by Nrf2-ARE.

  14. Resveratrol inhibits estrogen-induced breast carcinogenesis through induction of NRF2-mediated protective pathways

    PubMed Central

    Singh, Bhupendra; Shoulson, Rivka; Chatterjee, Anwesha; Ronghe, Amruta; Bhat, Nimee K.; Dim, Daniel C.; Bhat, Hari K.

    2014-01-01

    The importance of estrogens in the etiology of breast cancer is widely recognized. Estrogen-induced oxidative stress has been implicated in this carcinogenic process. Resveratrol (Res), a natural antioxidant phytoestrogen has chemopreventive effects against a variety of illnesses including cancer. The objective of the present study was to characterize the mechanism(s) of Res-mediated protection against estrogen-induced breast carcinogenesis. Female August Copenhagen Irish rats were treated with 17β-estradiol (E2), Res and Res + E2 for 8 months. Cotreatment of rats with Res and E2 inhibited E2-mediated proliferative changes in mammary tissues and significantly increased tumor latency and reduced E2-induced breast tumor development. Resveratrol treatment alone or in combination with E2 significantly upregulated expression of nuclear factor erythroid 2-related factor 2 (NRF2) in mammary tissues. Expression of NRF2-regulated antioxidant genes NQO1, SOD3 and OGG1 that are involved in protection against oxidative DNA damage was increased in Res- and Res + E2-treated mammary tissues. Resveratrol also prevented E2-mediated inhibition of detoxification genes AOX1 and FMO1. Inhibition of E2-mediated alterations in NRF2 promoter methylation and expression of NRF2 targeting miR-93 after Res treatment indicated Res-mediated epigenetic regulation of NRF2 during E2-induced breast carcinogenesis. Resveratrol treatment also induced apoptosis and inhibited E2-mediated increase in DNA damage in mammary tissues. Increased apoptosis and decreased DNA damage, cell migration, colony and mammosphere formation in Res- and Res + E2-treated MCF-10A cells suggested a protective role of Res against E2-induced mammary carcinogenesis. Small-interfering RNA-mediated silencing of NRF2 inhibited Res-mediated preventive effects on the colony and mammosphere formation. Taken together, these results suggest that Res inhibits E2-induced breast carcinogenesis via induction of NRF2-mediated protective

  15. Antioxidant mechanism of black garlic extract involving nuclear factor erythroid 2-like factor 2 pathway.

    PubMed

    Ha, Ae Wha; Kim, Woo Kyoung

    2017-06-01

    Although studies have revealed that black garlic is a potent antioxidant, its antioxidant mechanism remains unclear. The objective of this study was to determine black garlic's antioxidant activities and possible antioxidant mechanisms related to nuclear factor erythroid 2-like factor 2 (Nrf2)-Keap1 complex. After four weeks of feeding rats with a normal fat diet (NF), a high-fat diet (HF), a high-fat diet with 0.5% black garlic extract (HF+BGE 0.5), a high-fat diet with 1.0% black garlic extract (HF+BGE 1.0), or a high-fat diet with 1.5% black garlic extract (HF+BGE 1.5), plasma concentrations of glucose, insulin,homeostatic model assessment of insulin resistance (HOMA-IR) were determined. As oxidative stress indices, plasma concentrations of thiobarbituric acid reactive substances (TBARS) and 8-isoprostaglandin F2α (8-iso-PGF) were determined. To measure antioxidant capacities, plasma total antioxidant capacity (TAC) and activities of antioxidant enzymes in plasma and liver were determined. The mRNA expression levels of antioxidant related proteins such as Nrf2, NAD(P)H: quinone-oxidoreductase-1 (NQO1), heme oxygenase-1 (HO-1), glutathione reductase (GR), and glutathione S-transferase alpha 2 (GSTA2) were examined. Plasma glucose level, plasma insulin level, and HOMA-IR in black garlic supplemented groups were significantly ( P < 0.05) lower than those in the HF group without dose-dependent effect. Plasma TBARS concentration and TAC in the HF+BGE 1.5 group were significantly decreased compared to those of the HF group. The activities of catalase and glutathione peroxidase were significantly ( P < 0.05) increased in the HF+BGE 1.0 and HF+BGE 1.5 groups compared to those of the HF group. The mRNA expression levels of hepatic Nrf2, NQO1, HO-1, and GSTA2 were significantly ( P < 0.05) increased in the HF with BGE groups compared to those in the HF group. The improvements of blood glucose homeostasis and antioxidant systems in rats fed with black garlic extract were

  16. Antioxidant mechanism of black garlic extract involving nuclear factor erythroid 2-like factor 2 pathway

    PubMed Central

    Ha, Ae Wha

    2017-01-01

    BACKGROUN/OBJECTIVES Although studies have revealed that black garlic is a potent antioxidant, its antioxidant mechanism remains unclear. The objective of this study was to determine black garlic's antioxidant activities and possible antioxidant mechanisms related to nuclear factor erythroid 2-like factor 2 (Nrf2)-Keap1 complex. METHODS/MATERIALS After four weeks of feeding rats with a normal fat diet (NF), a high-fat diet (HF), a high-fat diet with 0.5% black garlic extract (HF+BGE 0.5), a high-fat diet with 1.0% black garlic extract (HF+BGE 1.0), or a high-fat diet with 1.5% black garlic extract (HF+BGE 1.5), plasma concentrations of glucose, insulin,homeostatic model assessment of insulin resistance (HOMA-IR) were determined. As oxidative stress indices, plasma concentrations of thiobarbituric acid reactive substances (TBARS) and 8-isoprostaglandin F2α (8-iso-PGF) were determined. To measure antioxidant capacities, plasma total antioxidant capacity (TAC) and activities of antioxidant enzymes in plasma and liver were determined. The mRNA expression levels of antioxidant related proteins such as Nrf2, NAD(P)H: quinone-oxidoreductase-1 (NQO1), heme oxygenase-1 (HO-1), glutathione reductase (GR), and glutathione S-transferase alpha 2 (GSTA2) were examined. RESULTS Plasma glucose level, plasma insulin level, and HOMA-IR in black garlic supplemented groups were significantly (P < 0.05) lower than those in the HF group without dose-dependent effect. Plasma TBARS concentration and TAC in the HF+BGE 1.5 group were significantly decreased compared to those of the HF group. The activities of catalase and glutathione peroxidase were significantly (P < 0.05) increased in the HF+BGE 1.0 and HF+BGE 1.5 groups compared to those of the HF group. The mRNA expression levels of hepatic Nrf2, NQO1, HO-1, and GSTA2 were significantly (P < 0.05) increased in the HF with BGE groups compared to those in the HF group. CONCLUSIONS The improvements of blood glucose homeostasis and

  17. Taxifolin Activates the Nrf2 Anti-Oxidative Stress Pathway in Mouse Skin Epidermal JB6 P+ Cells through Epigenetic Modifications

    PubMed Central

    Kuang, Haixue; Tang, Zhenqiu; Zhang, Chengyue; Wang, Zhibin; Li, Wenji; Yang, Chunjuan; Wang, Qiuhong; Yang, Bingyou; Kong, Ah-Ng

    2017-01-01

    Nuclear factor erythroid-2 related factor 2 (Nrf2) is a vital transcription factor that regulates the anti-oxidative defense system. Previous reports suggested that the expression of the Nrf2 gene can be regulated by epigenetic modifications. The potential epigenetic effect of taxifolin (TAX), a potent cancer chemopreventive agent, in skin cancer chemoprotection is unknown. In this study, we investigated how Nrf2 is epigenetically regulated by TAX in JB6 P+ cells. TAX was found to inhibit the 12-O-tetradecanoylphorbol-13-acetate (TPA)-induced colony formation of JB6 P+ cells. TAX induced antioxidant response element (ARE)-luciferase activity in HepG2-C8 cells and up-regulated mRNA and protein levels of Nrf2 and its downstream genes heme oxygenase-1 (HO-1) and NAD(P)H quinone oxidoreductase 1 (NQO1), in JB6 P+ cells. Furthermore, bisulfite genomic sequencing revealed that TAX treatment reduces the methylation level of the first 15 CpGs sites in the Nrf2 promoter. Western blotting showed that TAX inhibits the expression levels of DNA methyltransferase (DNMT) and histone deacetylase (HDAC) proteins. In summary, our results revealed that TAX can induce expression of Nrf2 and its downstream target genes in JB6 P+ cells by CpG demethylation. These finding suggest that TAX may exhibit a skin cancer preventive effect by activating Nrf2 via an epigenetic pathway. PMID:28714938

  18. Sulforaphane alleviates muscular dystrophy in mdx mice by activation of Nrf2.

    PubMed

    Sun, Chengcao; Yang, Cuili; Xue, Ruilin; Li, Shujun; Zhang, Ting; Pan, Lei; Ma, Xuejiao; Wang, Liang; Li, Dejia

    2015-01-15

    Sulforaphane (SFN), one of the most important isothiocyanates in the human diet, is known to have chemo-preventive and antioxidant activities in different tissues via activation of nuclear factor erythroid 2-related factor 2 (Nrf2)-mediated induction of antioxidant/phase II enzymes, such as heme oxygenase-1 and NAD(P)H quinone oxidoreductase 1. However, its effects on muscular dystrophy remain unknown. This work was undertaken to evaluate the effects of SFN on Duchenne muscular dystrophy. Four-week-old mdx mice were treated with SFN by gavage (2 mg·kg body wt(-1)·day(-1) for 8 wk), and our results demonstrated that SFN treatment increased the expression and activity of muscle phase II enzymes NAD(P)H quinone oxidoreductase 1 and heme oxygenase-1 with a Nrf2-dependent manner. SFN significantly increased skeletal muscle mass, muscle force (∼30%), running distance (∼20%), and GSH-to-GSSG ratio (∼3.2-fold) of mdx mice and decreased the activities of plasma creatine phosphokinase (∼45%) and lactate dehydrogenase (∼40%), gastrocnemius hypertrophy (∼25%), myocardial hypertrophy (∼20%), and malondialdehyde levels (∼60%). Furthermore, SFN treatment also reduced the central nucleation (∼40%), fiber size variability, and inflammation and improved the sarcolemmal integrity of mdx mice. Collectively, these results show that SFN can improve muscle function and pathology and protect dystrophic muscle from oxidative damage in mdx mice associated with Nrf2 signaling pathway, which indicate Nrf2 may have clinical implications for the treatment of patients with muscular dystrophy. Copyright © 2015 the American Physiological Society.

  19. Internal Pudental Artery Dysfunction in Diabetes Mellitus Is Mediated by NOX1-Derived ROS-, Nrf2-, and Rho Kinase-Dependent Mechanisms.

    PubMed

    Alves-Lopes, Rhéure; Neves, Karla B; Montezano, Augusto C; Harvey, Adam; Carneiro, Fernando S; Touyz, Rhian M; Tostes, Rita C

    2016-10-01

    Oxidative stress plays an important role in diabetes mellitus (DM)-associated vascular injury. DM is an important risk factor for erectile dysfunction. Functional and structural changes in internal pudendal arteries (IPA) can lead to erectile dysfunction. We hypothesized that downregulation of nuclear factor E2-related factor 2 (Nrf2), consequent to increased nicotinamide adenine dinucleotide phosphate oxidase 1 (NOX1)-derived reactive oxygen species (ROS), impairs IPA function in DM. IPA and vascular smooth muscle cells from C57BL/6 (control) and NOX1 knockout mice were used. DM was induced by streptozotocin in C57BL/6 mice. Functional properties of IPA were assessed using a myograph, protein expression and peroxiredoxin oxidation by Western blot, RNA expression by polymerase chain reaction, carbonylation by oxyblot assay, ROS generation by lucigenin, nitrotyrosine, and amplex red, and Rho kinase activity and nuclear accumulation of Nrf2 by ELISA. IPA from diabetic mice displayed increased contractions to phenylephrine (control 138.5±9.5 versus DM 191.8±15.5). ROS scavenger, Nrf2 activator, NOX1 and Rho kinase inhibitors normalized vascular function. High glucose increased ROS generation in IPA vascular smooth muscle cell. This effect was abrogated by Nrf2 activation and not observed in NOX1 knockout vascular smooth muscle cell. High glucose also increased levels of nitrotyrosine, protein oxidation/carbonylation, and Rho kinase activity, but reduced Nrf2 activity and expression of Nrf2-regulated genes (catalase [25.6±0.05%], heme oxygenase-1 [21±0.1%], and quinone oxidoreductase 1 [22±0.1%]) and hydrogen peroxide levels. These effects were not observed in vascular smooth muscle cell from NOX1 knockout mice. In these cells, high glucose increased hydrogen peroxide levels. In conclusion, Rho kinase activation, via NOX1-derived ROS and downregulation of Nrf2 system, impairs IPA function in DM. These data suggest that Nrf2 is vasoprotective in DM

  20. Temporal activation of Nrf2 in the penumbra and Nrf2 activator-mediated neuroprotection in ischemia-reperfusion injury.

    PubMed

    Takagi, Toshinori; Kitashoji, Akira; Iwawaki, Takao; Tsuruma, Kazuhiro; Shimazawa, Masamitsu; Yoshimura, Shinichi; Iwama, Toru; Hara, Hideaki

    2014-07-01

    Oxidative stress plays a critical role in mediating tissue injury and neuron death during ischemia-reperfusion injury (IRI). The Keap1-Nrf2 defense pathway serves as a master regulator of endogenous antioxidant defense, and Nrf2 has been attracting attention as a target for the treatment of IRI. In this study, we evaluated Nrf2 expression in IRI using OKD (Keap1-dependent oxidative stress detector) mice and investigated the neuroprotective ability of an Nrf2 activator. We demonstrated temporal changes in Nrf2 expression in the same mice with luciferase assays and an Nrf2 activity time course using Western blotting. We also visualized Nrf2 expression in the ischemic penumbra and investigated Nrf2 expression in mice and humans using immunohistochemistry. Endogenous Nrf2 upregulation was not detected early in IRI, but expression peaked 24h after ischemia. Nrf2 expression was mainly detected in the penumbra, and it was found in neurons and astrocytes in both mice and humans. Intravenous administration of the Nrf2 activator bardoxolone methyl (BARD) resulted in earlier upregulation of Nrf2 and heme oxygenase-1. Furthermore, BARD decreased infarction volume and improved neurological symptoms after IRI. These findings indicate that earlier Nrf2 activation protects neurons, possibly via effects on astrocytes. Copyright © 2014 Elsevier Inc. All rights reserved.

  1. Sulforaphane Attenuates Muscle Inflammation in Dystrophin-deficient mdx Mice via NF-E2-related Factor 2 (Nrf2)-mediated Inhibition of NF-κB Signaling Pathway.

    PubMed

    Sun, Cheng-Cao; Li, Shu-Jun; Yang, Cui-Li; Xue, Rui-Lin; Xi, Yong-Yong; Wang, Liang; Zhao, Qian-Long; Li, De-Jia

    2015-07-17

    Inflammation is widely distributed in patients with Duchenne muscular dystrophy and ultimately leads to progressive deterioration of muscle function with chronic muscle damage, oxidative stress, and reduced oxidative capacity. NF-E2-related factor 2 (Nrf2) plays a critical role in defending against inflammation in different tissues via activation of phase II enzyme heme oxygenase-1 and inhibition of the NF-κB signaling pathway. However, the role of Nrf2 in the inflammation of dystrophic muscle remains unknown. To determine whether Nrf2 may counteract inflammation in dystrophic muscle, we treated 4-week-old male mdx mice with the Nrf2 activator sulforaphane (SFN) by gavage (2 mg/kg of body weight/day) for 4 weeks. The experimental results demonstrated that SFN treatment increased the expression of muscle phase II enzyme heme oxygenase-1 in an Nrf2-dependent manner. Inflammation in mice was reduced by SFN treatment as indicated by decreased infiltration of immune cells and expression of the inflammatory cytokine CD45 and proinflammatory cytokines tumor necrosis factor-α, interleukin-1β, and interleukin-6 in the skeletal muscles of mdx mice. In addition, SFN treatment also decreased the expression of NF-κB(p65) and phosphorylated IκB kinase-α as well as increased inhibitor of κB-α expression in mdx mice in an Nrf2-dependent manner. Collectively, these results show that SFN-induced Nrf2 can alleviate muscle inflammation in mdx mice by inhibiting the NF-κB signaling pathway. © 2015 by The American Society for Biochemistry and Molecular Biology, Inc.

  2. Sulforaphane Attenuates Muscle Inflammation in Dystrophin-deficient mdx Mice via NF-E2-related Factor 2 (Nrf2)-mediated Inhibition of NF-κB Signaling Pathway*

    PubMed Central

    Sun, Cheng-Cao; Li, Shu-Jun; Yang, Cui-Li; Xue, Rui-Lin; Xi, Yong-Yong; Wang, Liang; Zhao, Qian-Long; Li, De-Jia

    2015-01-01

    Inflammation is widely distributed in patients with Duchenne muscular dystrophy and ultimately leads to progressive deterioration of muscle function with chronic muscle damage, oxidative stress, and reduced oxidative capacity. NF-E2-related factor 2 (Nrf2) plays a critical role in defending against inflammation in different tissues via activation of phase II enzyme heme oxygenase-1 and inhibition of the NF-κB signaling pathway. However, the role of Nrf2 in the inflammation of dystrophic muscle remains unknown. To determine whether Nrf2 may counteract inflammation in dystrophic muscle, we treated 4-week-old male mdx mice with the Nrf2 activator sulforaphane (SFN) by gavage (2 mg/kg of body weight/day) for 4 weeks. The experimental results demonstrated that SFN treatment increased the expression of muscle phase II enzyme heme oxygenase-1 in an Nrf2-dependent manner. Inflammation in mice was reduced by SFN treatment as indicated by decreased infiltration of immune cells and expression of the inflammatory cytokine CD45 and proinflammatory cytokines tumor necrosis factor-α, interleukin-1β, and interleukin-6 in the skeletal muscles of mdx mice. In addition, SFN treatment also decreased the expression of NF-κB(p65) and phosphorylated IκB kinase-α as well as increased inhibitor of κB-α expression in mdx mice in an Nrf2-dependent manner. Collectively, these results show that SFN-induced Nrf2 can alleviate muscle inflammation in mdx mice by inhibiting the NF-κB signaling pathway. PMID:26013831

  3. The effect of natural antioxidants in cyclophosphamide-induced hepatotoxicity: Role of Nrf2/HO-1 pathway.

    PubMed

    Sherif, Iman O

    2018-05-22

    Hepatotoxicity induced by cyclophosphamide (Cyclo) is a major concern in clinical practice. This study was designed to investigate the possible cytoprotective effect of natural antioxidants as oleuropein and quercetin against Cyclo induced hepatotoxicity via the nuclear factor erythroid 2-related factor 2 (Nrf2)/heme oxygenase-1 (HO-1) signaling pathway. Male Wistar rats were randomly divided into six groups and treated for 10 days as follow: Group I (Normal control) received saline, group II (Oleu control): received orally oleuropein 30 mg/kg/day, group III (Quer control): administered orally quercetin 50 mg/kg/day, group IV (Cyclo): received saline and injected with single intraperitoneal (i.p) dose of Cyclo 200 mg/kg at day 5, group V (Oleu ttt): treated with oleuropein plus Cyclo i.p. injection at day 5, and group VI (Quer ttt): treated with quercetin plus Cyclo i.p. injection at day 5. Injection of Cyclo showed marked increase in serum transaminases and alkaline phosphatase, hepatic malondialdehyde (MDA) and tumor necrosis factor-alpha (TNF-⍺) levels along with significant reduction in hepatic reduced glutathione (GSH), superoxide dismutase (SOD), and catalase levels in addition to downregulation of hepatic Nrf2 and HO-1 expressions and reduction in hepatic nuclear Nrf2 binding activity when compared with normal group. Histopathological examination of Cyclo treated rats revealed hepatic damage. Both oleuropein and quercetin exhibited an improvement in the biochemical and histopathological findings. In conclusion, the natural antioxidants oleuropein and quercetin counteract the Cyclo induced hepatotoxicity through activation of Nrf2/HO-1 signaling pathway with subsequent suppression of oxidative stress and inflammation. Copyright © 2018 Elsevier B.V. All rights reserved.

  4. 4-hydroxy-2-nonenal protects against cardiac ischemia-reperfusion injury via the Nrf2-dependent pathway.

    PubMed

    Zhang, Yan; Sano, Motoaki; Shinmura, Ken; Tamaki, Kayoko; Katsumata, Yoshinori; Matsuhashi, Tomohiro; Morizane, Shintaro; Ito, Hideyuki; Hishiki, Takako; Endo, Jin; Zhou, Heping; Yuasa, Shinsuke; Kaneda, Ruri; Suematsu, Makoto; Fukuda, Keiichi

    2010-10-01

    Reactive oxygen species (ROS) attack polyunsaturated fatty acids of the membrane and trigger lipid peroxidation, which results in the generation of alpha,beta-unsaturated aldehydes, such as 4-hydroxy-2-nonenal (4-HNE). There is compelling evidence that high concentrations of aldehydes are responsible for much of the damage elicited by cardiac ischemia-reperfusion injury, while sublethal concentrations of aldehydes stimulate stress resistance pathways, to achieve cardioprotection. We investigated the mechanism of cardioprotection mediated by 4-HNE. For cultured cardiomyocytes, 4-HNE was cytotoxic at higher concentrations (>or=20 microM) but had no appreciable cytotoxicity at lower concentrations. Notably, a sublethal concentration (5muM) of 4-HNE primed cardiomyocytes to become resistant to cytotoxic concentrations of 4-HNE. 4-HNE induced nuclear translocation of transcription factor NF-E2-related factor 2 (Nrf2), and enhanced the expression of gamma-glutamylcysteine ligase (GCL) and the core subunit of the Xc(-) high-affinity cystine transporter (xCT), thereby increasing 1.45-fold the intracellular GSH levels. Cardiomyocytes treated with either Nrf2-specific siRNA or the GCL inhibitor l-buthionine sulfoximine (BSO) were less tolerant to 4-HNE. Moreover, the cardioprotective effect of 4-HNE pretreatment against subsequent glucose-free anoxia followed by reoxygenation was completely abolished in these cells. Intravenous administration of 4-HNE (4 mg/kg) activated Nrf2 in the heart and increased the intramyocardial GSH content, and consequently improved the functional recovery of the left ventricle following ischemia-reperfusion in Langendorff-perfused hearts. This cardioprotective effect of 4-HNE was not observed for Nrf2-knockout mice. In summary, 4-HNE activates Nrf2-mediated gene expression and stimulates GSH biosynthesis, thereby conferring on cardiomyocytes protection against ischemia-reperfusion injury. Copyright 2010 Elsevier Ltd. All rights reserved.

  5. Fisetin alleviates oxidative stress after traumatic brain injury via the Nrf2-ARE pathway.

    PubMed

    Zhang, Li; Wang, Handong; Zhou, Yali; Zhu, Yihao; Fei, Maoxin

    2018-05-22

    Fisetin, a natural flavonoid, has neuroprotection properties in many brain injury models. However, its role in traumatic brain injury (TBI) has not been fully explained. In the present study, we aimed to explore the neuroprotective effects of fisetin in a mouse model of TBI. We found that fisetin improved neurological function, reduced cerebral edema, attenuated brain lesion and ameliorated blood-brain barrier (BBB) disruption after TBI. Moreover, the up-regulation of malondialdehyde (MDA) and the activity of glutathione peroxidase (GPx) were reversed by fisetin treatment. Furthermore, administration of fisetin suppressed neuron cell death and apoptosis, increased the expression of B-cell lymphoma 2 (Bcl-2), while decreased the expression of Bcl-2-associated X protein (Bax) and caspase-3 after TBI. In addition, fisetin activated the nuclear factor erythroid 2-related factor 2 (Nrf2)-antioxidant response element (ARE) pathway following TBI. However, fisetin only failed to suppress oxidative stress in Nrf2 -/- mice. In conclusion, our data provided the first evidence that fisetin played a critical role in neuroprotection after TBI partly through the activation of the Nrf2-ARE pathway. Copyright © 2018 Elsevier Ltd. All rights reserved.

  6. Green tea polyphenol (−)-epigallocatechin-3-gallate triggered hepatotoxicity in mice: Responses of major antioxidant enzymes and the Nrf2 rescue pathway

    DOE Office of Scientific and Technical Information (OSTI.GOV)

    Wang, Dongxu; Wang, Yijun; Wan, Xiaochun

    (−)-Epigallocatechin-3-gallate (EGCG), a constituent of green tea, has been suggested to have numerous health-promoting effects. On the other hand, high-dose EGCG is able to evoke hepatotoxicity. In the present study, we elucidated the responses of hepatic major antioxidant enzymes and nuclear factor erythroid 2-related factor 2 (Nrf2) rescue pathway to high-dose levels of EGCG in Kunming mice. At a non-lethal toxic dose (75 mg/kg, i.p.), repeated EGCG treatments markedly decreased the levels of superoxide dismutase, catalase, and glutathione peroxidase. As a rescue response, the nuclear distribution of Nrf2 was significantly increased; a battery of Nrf2-target genes, including heme oxygenase 1more » (HO1), NAD(P)H:quinone oxidoreductase 1 (NQO1), glutathione S-transferase (GST), and those involved in glutathione and thioredoxin systems, were all up-regulated. At the maximum tolerated dose (45 mg/kg, i.p.), repeated EGCG treatments did not disturb the major antioxidant defense. Among the above-mentioned genes, only HO1, NQO1, and GST genes were significantly but modestly up-regulated, suggesting a comprehensive and extensive activation of Nrf2-target genes principally occurs at toxic levels of EGCG. At a lethal dose (200 mg/kg, i.p.), a single EGCG treatment dramatically decreased not only the major antioxidant defense but also the Nrf2-target genes, demonstrating that toxic levels of EGCG are able to cause a biphasic response of Nrf2. Overall, the mechanism of EGCG-triggered hepatotoxicity involves suppression of major antioxidant enzymes, and the Nrf2 rescue pathway plays a vital role for counteracting EGCG toxicity. - Highlights: • EGCG at maximum tolerated dose does not disturb hepatic major antioxidant defense. • EGCG at maximum tolerated dose modestly upregulates hepatic Nrf2 target genes. • EGCG at toxic dose suppresses hepatic major antioxidant enzymes. • EGCG at non-lethal toxic dose pronouncedly activates hepatic Nrf2 rescue response. • EGCG

  7. Naringenin protects against 6-OHDA-induced neurotoxicity via activation of the Nrf2/ARE signaling pathway.

    PubMed

    Lou, Haiyan; Jing, Xu; Wei, Xinbing; Shi, Huanying; Ren, Dongmei; Zhang, Xiumei

    2014-04-01

    There is increasing evidence that oxidative stress is critically involved in the pathogenesis of Parkinson's disease (PD), suggesting that pharmacological targeting of the antioxidant machinery may have therapeutic value. Naringenin, a natural flavonoid compound, has been reported to possess neuroprotective effect against PD related pathology; however the mechanisms underlying its beneficial effects are poorly defined. Thus, the purpose of the present study was to investigate the potential neuroprotective role of naringenin and to delineate its mechanism of action against 6-hydroxydopamine (6-OHDA)-induced neurotoxicity in models of PD both in vitro and in vivo. Naringenin treatment resulted in an increase in nuclear factor E2-related factor 2 (Nrf2) protein levels and subsequent activation of antioxidant response element (ARE) pathway genes in SH-SY5Y cells and in mice. Exposure of SH-SY5Y cells to naringenin provided protection against 6-OHDA-induced oxidative insults that was dependent on Nrf2, since treatment with Nrf2 siRNA failed to block against 6-OHDA neurotoxicity or induce Nrf2-dependent cytoprotective genes in SH-SY5Y cells. In mice, oral administration of naringenin resulted in significant protection against 6-OHDA-induced nigrostriatal dopaminergic neurodegeneration and oxidative damage. Our results indicate that activation of Nrf2/ARE signaling by naringenin is strongly associated with its neuroprotective effects against 6-OHDA neurotoxicity and suggest that targeting the Nrf2/ARE pathway may be a promising approach for therapeutic intervention in PD. Copyright © 2013 Elsevier Ltd. All rights reserved.

  8. Andrographolide stimulates p38 mitogen-activated protein kinase-nuclear factor erythroid-2-related factor 2-heme oxygenase 1 signaling in primary cerebral endothelial cells for definite protection against ischemic stroke in rats.

    PubMed

    Yen, Ting-Lin; Chen, Ray-Jade; Jayakumar, Thanasekaran; Lu, Wan-Jung; Hsieh, Cheng-Ying; Hsu, Ming-Jen; Yang, Chih-Hao; Chang, Chao-Chien; Lin, Yen-Kuang; Lin, Kuan-Hung; Sheu, Joen-Rong

    2016-04-01

    Stroke pathogenesis involves complex oxidative stress-related pathways. The nuclear factor erythroid-2-related factor 2 (Nrf2) and heme oxygenase 1 (HO-1) pathways have been considered molecular targets in pharmacologic intervention for ischemic diseases. Andrographolide, a labdane diterpene, has received increasing attention in recent years because of its various pharmacologic activities. We determined that andrographolide modulates the mitogen-activated protein kinase (MAPK)-Nrf2-HO-1 signaling cascade in primary cerebral endothelial cells (CECs) to provide positive protection against middle cerebral artery occlusion (MCAO)-induced ischemic stroke in rats. In the present study, andrographolide (10 μM) increased HO-1 protein and messenger RNA expressions, Nrf2 phosphorylation, and nuclear translocation in CECs, and these activities were disrupted by a p38 MAPK inhibitor, SB203580, but not by the extracellular signal-regulated kinase inhibitor PD98059 or c-Jun amino-terminal kinase inhibitor SP600125. Similar results were observed in confocal microscopy analysis. Moreover, andrographolide-induced Nrf2 and HO-1 protein expressions were significantly inhibited by Nrf2 small interfering RNA. Moreover, HO-1 knockdown attenuated the protective effect of andrographolide against oxygen-glucose deprivation-induced CEC death. Andrographolide (0.1 mg/kg) significantly suppressed free radical formation, blood-brain barrier disruption, and brain infarction in MCAO-insulted rats, and these effects were reversed by the HO-1 inhibitor zinc protoporphyrin IX. The mechanism is attributable to HO-1 activation, as directly evidenced by andrographolide-induced pronounced HO-1 expression in brain tissues, which was highly localized in the cerebral capillary. In conclusion, andrographolide increased Nrf2-HO-1 expression through p38 MAPK regulation, confirming that it provides protection against MCAO-induced brain injury. These findings provide strong evidence that andrographolide could

  9. Effects of Nrf2 knockdown on the properties of irradiated cell conditioned medium from A549 human lung cancer cells.

    PubMed

    Yoshino, Hironori; Murakami, Kanna; Nawamaki, Mikoto; Kashiwakura, Ikuo

    2018-05-01

    The nuclear factor erythroid 2-related factor 2 (Nrf2) plays an important role in cellular defense against oxidative stress. Recent studies have demonstrated that Nrf2 is a useful target for cancer treatment, including radiation therapy. Ionizing radiation affects, not only the irradiated cells, but also the non-irradiated neighboring cells, and this effect is known as radiation-induced bystander effect. Upon exposure to radiation, the irradiated cells transmit signals to the non-irradiated cells via gap junctions or soluble factors. These signals in turn cause biological effects, such as a decrease in the clonogenic potential and cell death, in the non-irradiated neighboring cells. Nrf2 inhibition enhances cellular radiosensitivity. However, whether this modification of radiosensitivity by Nrf2 inhibition affects the radiation-induced bystander effects is unknown. In this study, we prepared an Nrf2 knockdown human lung cancer cell A549 and investigated whether the effects of irradiated cell conditioned medium (ICCM) on cell growth and cell death induction of non-irradiated cells vary depending on the Nrf2 knockdown. We found that Nrf2 knockdown resulted in a decrease in the cell growth and an increase in the radiosensitivity of A549 cells. When non-irradiated A549 cells were transfected with control siRNA and treated with ICCM, no significant difference was observed in the cell growth and proportion of Annexin V + dead cells between ICCM from non-irradiated cells and that from 2 or 8 Gy-irradiated cells. Similarly, no significant difference was observed in the cell growth and cell death induction upon treatment with ICCM in the Nrf2 knockdown A549 cells. Taken together, these results suggest that Nrf2 knockdown decreases cell growth and enhances the radiosensitivity of A549 cells; however, it does not alter the effect of ICCM on cell growth.

  10. Nuclear factor E2-related factor-2 has a differential impact on MCT1 and MCT4 lactate carrier expression in colonic epithelial cells: a condition favoring metabolic symbiosis between colorectal cancer and stromal cells.

    PubMed

    Diehl, K; Dinges, L-A; Helm, O; Ammar, N; Plundrich, D; Arlt, A; Röcken, C; Sebens, S; Schäfer, H

    2018-01-04

    Malignant tumors, such as colorectal cancer (CRC), are heterogeneous diseases characterized by distinct metabolic phenotypes. These include Warburg- and reverse Warburg phenotypes depending on differential distribution of the lactate carrier proteins monocarboxylate transporter-4 and -1 (MCT4 and MCT1). Here, we elucidated the role of the antioxidant transcription factor nuclear factor E2-related factor-2 (Nrf2) as the key regulator of cellular adaptation to inflammatory/environmental stress in shaping the metabolism toward a reverse Warburg phenotype in malignant and premalignant colonic epithelial cells. Immunohistochemistry of human CRC tissues revealed reciprocal expression of MCT1 and MCT4 in carcinoma and stroma cells, respectively, accompanied by strong epithelial Nrf2 activation. In colorectal tissue from inflammatory bowel disease patients, MCT1 and Nrf2 were coexpressed as well, relating to CD68+inflammatory infiltrates. Indirect coculture of human NCM460 colonocytes with M1- but not M2 macrophages induces MCT1 as well as G6PD, LDHB and TALDO expression, whereas MCT4 expression was decreased. Nrf2 knockdown or reactive oxygen species (ROS) scavenging blocked these coculture effects in NCM460 cells. Likewise, Nrf2 knockdown inhibited similar effects of tBHQ-mediated Nrf2 activation on NCM460 and HCT15 CRC cells. M1 coculture or Nrf2 activation/overexpression greatly altered the lactate uptake but not glucose uptake and mitochondrial activities in these cells, reflecting the reverse Warburg phenotype. Depending on MCT1-mediated lactate uptake, Nrf2 conferred protection from TRAIL-induced apoptosis in NCM460 and HCT15 cells. Moreover, metabolism-dependent clonal growth of HCT15 cells was induced by Nrf2-dependent activation of MCT1-driven lactate exchange. These findings indicate that Nrf2 has an impact on the metabolism already in premalignant colonic epithelial cells exposed to inflammatory M1 macrophages, an effect accompanied by growth and survival

  11. Suppression of antioxidant Nrf-2 and downstream pathway in H9c2 cells by advanced glycation end products (AGEs) via ERK phosphorylation.

    PubMed

    Ko, Shun-Yao; Chang, Shu-Shing; Lin, I-Hsuan; Chen, Hong-I

    2015-11-01

    Diabetic cardiomyopathy is related to oxidative stress and correlated with the presence of advanced glycation end products (AGEs). In a clinical setting, AGEs can be detected in patients presenting diabetic cardiomyopathy; however, the underlying mechanism has yet to be elucidated. In our previous study, AGEs increase cell hypertrophy via ERK phosphorylation in a process closely related to ROS production. Thus, we propose that AGEs regulate the antioxidant gene nuclear factor-erythroid 2-related factor (Nrf-2). In H9c2 cells treated with AGEs, the expression of Nrf-2 was reduced; however, ERK phosphorylation was shown to increase. Treatment with H2O2 was also shown to increase Nrf-2 and ERK phosphorylation. In cells pretreatment with ROS scavenger NAC, the effects of H2O2 were reduced; however, the effects of the AGEs remained largely unchanged. Conversely, when cells were pretreated with PD98059 (ERK inhibitor), the expression of Nrf-2 was recovered following treatment with AGEs. Our results suggest that AGEs inhibit Nrf-2 via the ERK pathway; however, this influence is partly associated with ROS. Our finding further indicated that AGEs possess both ROS-dependent and ROS-independent pathways, resulting in a reduction in Nrf-2. This report reveals an important mechanism underlying the regulation of diabetic cardiomyopathy progression by AGEs. Copyright © 2015 Elsevier B.V. and Société Française de Biochimie et Biologie Moléculaire (SFBBM). All rights reserved.

  12. Nrf2-dependent protection against acute sodium arsenite toxicity in zebrafish

    DOE Office of Scientific and Technical Information (OSTI.GOV)

    Fuse, Yuji; Nguyen, Vu Thanh; Kobayashi, Makoto, E

    Transcription factor Nrf2 induces a number of detoxifying enzymes and antioxidant proteins to confer protection against the toxic effects of a diverse range of chemicals including inorganic arsenicals. Although a number of studies using cultured cells have demonstrated that Nrf2 has a cell-protective function against acute and high-dose arsenic toxicity, there is no clear in vivo evidence of this effect. In the present study, we genetically investigated the protective role of Nrf2 against acute sodium arsenite toxicity using the zebrafish Nrf2 mutant, nrf2a{sup fh318}. After treatment with 1 mM sodium arsenite, the survival of nrf2a{sup fh318} larvae was significantly shortermore » than that of wild-type siblings, suggesting that Nrf2 protected the zebrafish larvae against high-dose arsenite exposure. To understand the molecular basis of the Nrf2-dependent protection, we analyzed the gene expression profiles after arsenite exposure, and found that the genes involved in the antioxidative function (prdx1 and gclc), arsenic metabolism (gstp1) and xenobiotic elimination (abcc2) were induced in an Nrf2-dependent manner. Furthermore, pre-treatment with sulforaphane, a well-known Nrf2 activator improved the survival of zebrafish larvae after arsenic exposure. Based on these results, we concluded that Nrf2 plays a fundamental and conserved role in protection against acute sodium arsenite toxicity. - Highlights: • The role of Nrf2 under arsenite exposure was valuated using zebrafish. • Nrf2 mutant zebrafish was highly sensitive to acute arsenic toxicity. • Nrf2 induced anti-arsenic genes in response to arsenite. • Sulforaphane attenuated arsenic toxicity through Nrf2 activation. • Nrf2 system plays an important role in the defense against acute arsenic toxicity.« less

  13. Continuous activation of Nrf2 and its target antioxidant enzymes leads to arsenite-induced malignant transformation of human bronchial epithelial cells

    DOE Office of Scientific and Technical Information (OSTI.GOV)

    Yang, Xu; Wang, Dapeng; Department of Toxicology, School of Public Health, Guizhou Medical University, Guiyang, Guizhou

    Long-term exposure to arsenite leads to human lung cancer, but the underlying mechanisms of carcinogenesis remain obscure. The transcription factor of nuclear factor-erythroid-2 p45-related factor (Nrf2)-mediated antioxidant response represents a critical cellular defense mechanism and protection against various diseases. Paradoxically, emerging data suggest that the constitutive activation of Nrf2 is associated with cancer development, progression and chemotherapy resistance. However, the role of Nrf2 in the occurrence of cancer induced by long-term arsenite exposure remains to be fully understood. By establishing transformed human bronchial epithelial (HBE) cells via chronic low-dose arsenite treatment, we showed that, in acquiring this malignant phenotype, continuousmore » low level of ROS and sustained enhancement of Nrf2 and its target antioxidant enzyme levels were observed in the later-stage of arsenite-induced cell transformation. The downregulation of Keap1 level may be responsible for the over-activation of Nrf2 and its target enzymes. To validate these observations, Nrf2 was knocked down in arsenite-transformed HBE cells by SiRNA transfection, and the levels of Nrf2 and its target antioxidant enzymes, ROS, cell proliferation, migration, and colony formation were determined following these treatments. Results showed that blocked Nrf2 expression significantly reduced Nrf2 and its target antioxidant enzyme levels, restored ROS levels, and eventually suppressed cell proliferation, migration, and colony formation of the transformed cells. In summary, the results of the study strongly suggested that the continuous activation of Nrf2 and its target antioxidant enzymes led to the over-depletion of intracellular ROS levels, which contributed to arsenite-induced HBE cell transformation. - Highlights: • Low level, long term arsenite exposure induces malignant transformation in vitro. • Long term arsenite exposure reduces ROS and MDA levels. • Long term

  14. Antioxidant Opuntia ficus-indica Extract Activates AHR-NRF2 Signaling and Upregulates Filaggrin and Loricrin Expression in Human Keratinocytes.

    PubMed

    Nakahara, Takeshi; Mitoma, Chikage; Hashimoto-Hachiya, Akiko; Takahara, Masakazu; Tsuji, Gaku; Uchi, Hiroshi; Yan, Xianghong; Hachisuka, Junichi; Chiba, Takahito; Esaki, Hitokazu; Kido-Nakahara, Makiko; Furue, Masutaka

    2015-10-01

    Opuntia ficus-indica (OFI) is a cactus species widely used as an anti-inflammatory, antilipidemic, and hypoglycemic agent. It has been shown that OFI extract (OFIE) inhibits oxidative stress in animal models of diabetes and hepatic disease; however, its antioxidant mechanism remains largely unknown. In this study, we demonstrated that OFIE exhibited potent antioxidant activity through the activation of nuclear factor erythroid 2-related factor 2 (NRF2) and the downstream antioxidant enzyme quinone oxidoreductase 1 (NQO1), which inhibited the generation of reactive oxygen species in keratinocytes challenged with tumor necrosis factor α or benzo[α]pyrene. The antioxidant capacity of OFIE was canceled in NRF2 knockdown keratinocytes. OFIE exerted this NRF2-NQO1 upregulation through activation of the aryl hydrocarbon receptor (AHR). Moreover, the ligation of AHR by OFIE upregulated the expression of epidermal barrier proteins: filaggrin and loricrin. OFIE also prevented TH2 cytokine-mediated downregulation of filaggrin and loricrin expression in an AHR-dependent manner because it was canceled in AHR knockdown keratinocytes. Antioxidant OFIE is a potent activator of AHR-NRF2-NQO1 signaling and may be beneficial in treating barrier-disrupted skin disorders.

  15. Sofalcone, a gastric mucosa protective agent, increases vascular endothelial growth factor via the Nrf2-heme-oxygenase-1 dependent pathway in gastric epithelial cells

    DOE Office of Scientific and Technical Information (OSTI.GOV)

    Shibuya, Akiko; Onda, Kenji, E-mail: knjond@toyaku.ac.jp; Kawahara, Hirofumi

    2010-07-30

    Research highlights: {yields} Sofalcone increases HO-1 in gastric epithelial cells. {yields} The induction of HO-1 by sofalcone treatment follows the activation of Nrf2. {yields} The production of VEGF by sofalcone treatment is mediated by HO-1 induction. -- Abstract: Sofalcone, 2'-carboxymethoxy-4,4-bis(3-methyl-2-butenyloxy)chalcone, is an anti-ulcer agent that is classified as a gastric mucosa protective agent. Recent studies indicate heat shock proteins such as HSP32, also known as heme-oxygenase-1(HO-1), play important roles in protecting gastrointestinal tissues from several stresses. We have previously reported that sofalcone increases the expression of HO-1 in adipocytes and pre-adipocytes, although the effect of sofalcone on HO-1 induction inmore » gastrointestinal tissues is not clear. In the current study, we investigated the effects of sofalcone on the expression of HO-1 and its functional role in rat gastric epithelial (RGM-1) cells. We found that sofalcone increased HO-1 expression in RGM-1 cells in both time- and concentration-dependent manners. The HO-1 induction was associated with the nuclear translocation of nuclear factor (erythroid-derived 2)-like 2 (Nrf2) in RGM-1 cells. We also observed that sofalcone increased vascular endothelial growth factor (VEGF) production in the culture medium. Treatment of RGM-1 cells with an HO-1 inhibitor (tin-protoporphyrin), or HO-1 siRNA inhibited sofalcone-induced VEGF production, suggesting that the effect of sofalcone on VEGF expression is mediated by the HO-1 pathway. These results suggest that the gastroprotective effects of sofalcone are partly exerted via Nrf2-HO-1 activation followed by VEGF production.« less

  16. Osthole improves acute lung injury in mice by up-regulating Nrf-2/thioredoxin 1.

    PubMed

    Chen, Xiang-Jun; Zhang, Bo; Hou, Shao-Jie; Shi, Yun; Xu, Dun-Quan; Wang, Yan-Xia; Liu, Man-Ling; Dong, Hai-Ying; Sun, Ri-He; Bao, Nan-Di; Jin, Fa-Guang; Li, Zhi-Chao

    2013-08-15

    Inhibiting reactive oxygen species (ROS) has been viewed as a therapeutic target for the treatment of acute lung injury (ALI). Osthole, an active component in Chinese herbal medicine, has drawn increasing attention because of its various pharmacological functions, including anti-inflammatory and anti-oxidative activities. The aim of the present study was to examine the effects of osthole on ALI induced by lipopolysaccharide (LPS) through intratracheal instillation. The mRNA and protein expression levels of thioredoxin 1 (Trx1) and the nuclear factor erythroid-2 related factor 2 (Nrf2) were detected by real-time PCR, reverse transcription PCR (RT-PCR) and Western blot, respectively. ROS production was measured by flow cytometry. Our results showed that osthole treatment improved the mice survival rates in the middle and high dosage groups, compared with the untreated LPS group. Moreover, osthole treatment significantly improved LPS-induced lung pathological damage, and it decreased the lung injury scores, lung wet/dry ratios and the total protein level in Bronchoalveolar lavage fluid (BALF). Osthole treatment dramatically reduced the H2O2, MDA and OH levels in the lung homogenates. LDH and ROS were markedly reduced in the osthole+LPS group in vitro. Furthermore, osthole increased Nrf2 and Trx1 expression in terms of mRNA and protein in vivo and in vitro. Nrf2 siRNA (siNrf2) could suppress the beneficial effects of osthole on ALI. In conclusion, the current study demonstrates that osthole exerted protective effects on LPS-induced ALI by up-regulating the Nrf-2/Trx-1 pathway. Copyright © 2013 Elsevier B.V. All rights reserved.

  17. Nuclear translocation of Nrf2 and expression of antioxidant defence genes in THP-1 cells exposed to carbon nanotubes.

    PubMed

    Brown, David M; Donaldson, Kenneth; Stone, Vicki

    2010-06-01

    Carbon nanotubes have a wide range of applications in various industries and their use is likely to rise in the future. Currently, a major concern is that with the increasing use and production of these materials, there may be increased health risks to exposed workers. Long (> 15 microm) straight nanotubes may undergo frustrated phagocytosis which is likely to result in reduced clearance. We examine here the effects of multiwalled carbon nanotubes of different sizes on monocytic THP-1 cells, with regard to their ability to stimulate increased expression of the HO-1 and GST genes and their ability to produce nuclear translocation of the transcription factor, Nrf2, as well as the release of several pro-inflammatory cytokines and mediators of inflammation. Our results suggest that long (50 microm) carbon nanotubes (62.5 microg/ml for 4 hours) produce increased nuclear translocation of Nrf2 and increased HO-1 gene expression compared with shorter entangled nanotubes. There was no increased gene expression for GST. The long nanotubes (NT1) caused increased release of the proinflammatory cytokine IL-1beta, an effect which was diminished by the antioxidant trolox, suggesting a role of oxidative stress in the upregulation of this cytokine. Tentatively, our study suggests that long carbon nanotubes may exert their effect in THP-1 cells in part via an oxidative stress mechanism.

  18. Anti-Inflammatory Mechanism Involved in Pomegranate-Mediated Prevention of Breast Cancer: the Role of NF-κB and Nrf2 Signaling Pathways

    PubMed Central

    Mandal, Animesh; Bhatia, Deepak; Bishayee, Anupam

    2017-01-01

    Pomegranate (Punica granatum L.), a nutrient-rich unique fruit, has been used for centuries for the prevention and treatment of various inflammation-driven diseases. Based on our previous study, a characterized pomegranate emulsion (PE) exhibited a striking inhibition of dimethylbenz(a)anthracene (DMBA)-initiated rat mammary tumorigenesis via antiproliferative and apoptosis-inducing mechanisms. The objective of the present work is to investigate the anti-inflammatory mechanism of action of PE during DMBA rat mammary carcinogenesis by evaluating the expression of cyclooxygenase-2 (COX-2), heat shock protein 90 (HSP90), nuclear factor-κB (NF-κB) and nuclear factor erythroid 2p45 (NF-E2)-related factor 2 (Nrf2). Mammary tumor samples were harvested from our previous chemopreventive study in which PE (0.2–5.0 g/kg) was found to reduce mammary tumorigenesis in a dose-dependent manner. The expressions of COX-2, HSP90, NF-κB, inhibitory κBα (IκBα) and Nrf2 were detected by immunohistochemical techniques. PE decreased the expression of COX-2 and HSP90, prevented the degradation of IκBα, hindered the translocation of NF-κB from cytosol to nucleus and increased the expression and nuclear translocation of Nrf2 during DMBA-induced mammary tumorigenesis. These findings, together with our previous results, indicate that PE-mediated prevention of DMBA-evoked mammary carcinogenesis may involve anti-inflammatory mechanisms through concurrent but differential regulation of two interrelated molecular pathways, namely NF-κB and Nrf2 signaling. PMID:28452959

  19. Brain ischemic preconditioning protects against ischemic injury and preserves the blood-brain barrier via oxidative signaling and Nrf2 activation.

    PubMed

    Yang, Tuo; Sun, Yang; Mao, Leilei; Zhang, Meijuan; Li, Qianqian; Zhang, Lili; Shi, Yejie; Leak, Rehana K; Chen, Jun; Zhang, Feng

    2018-05-06

    Brain ischemic preconditioning (IPC) with mild ischemic episodes is well known to protect the brain against subsequent ischemic challenges. However, the underlying mechanisms are poorly understood. Here we demonstrate the critical role of the master redox transcription factor, nuclear factor (erythroid-derived 2)-like 2 (Nrf2), in IPC-mediated neuroprotection and blood-brain barrier (BBB) preservation. We report that IPC causes generation of endogenous lipid electrophiles, including 4-hydroxy-2-nonenal (4-HNE), which release Nrf2 from inhibition by Keap1 (via Keap1-C288) and inhibition by glycogen synthase kinase 3β (via GSK3β-C199). Nrf2 then induces expression of its target genes, including a new target, cadherin 5, a key component of adherens junctions of the BBB. These effects culminate in mitigation of BBB leakage and of neurological deficits after stroke. Collectively, these studies are the first to demonstrate that IPC protects the BBB against ischemic injury by generation of endogenous electrophiles and activation of the Nrf2 pathway through inhibition of Keap1- and GSK3β-dependent Nrf2 degradation. Copyright © 2018 The Authors. Published by Elsevier B.V. All rights reserved.

  20. Treatment of Parkinson's disease in rats by Nrf2 transfection using MRI-guided focused ultrasound delivery of nanomicrobubbles

    DOE Office of Scientific and Technical Information (OSTI.GOV)

    Long, Ling; Cai, Xiaodong; Guo, Ruomi

    Parkinson's disease (PD) is a very common neurological disorder. However, effective therapy is lacking. Although the blood-brain-barrier (BBB) protects the brain, it prevents the delivery of about 90% of drugs and nucleotides into the brain, thereby hindering the development of gene therapy for PD. Magnetic resonance imaging (MRI)-guided focused ultrasound delivery of microbubbles enhances the delivery of gene therapy vectors across the BBB and improves transfection efficiency. In the present study, we delivered nuclear factor E2-related factor 2 (Nrf2, NFE2L2) contained in nanomicrobubbles into the substantia nigra of PD rats by MRI-guided focused ultrasound, and we examined the effect ofmore » Nrf2 over-expression in this animal model of PD. The rat model of PD was established by injecting 6-OHDA in the right substantia nigra stereotactically. Plasmids (pDC315 or pDC315/Nrf2) were loaded onto nanomicrobubbles, and then injected through the tail vein with the assistance of MRI-guided focused ultrasound. MRI-guided focused ultrasound delivery of nanomicrobubbles increased gene transfection efficiency. Furthermore, Nrf2 gene transfection reduced reactive oxygen species levels, thereby protecting neurons in the target region. - Highlights: • MRI-guided focused ultrasound enhances gene transfection into the brain of rats. • Increased Nrf2 expression protects neurons in the rat model of PD. • Nrf2 protects neurons in PD by inhibiting ROS production.« less

  1. Complexity of CNC transcription factors as revealed by gene targeting of the Nrf3 locus.

    PubMed

    Derjuga, Anna; Gourley, Tania S; Holm, Teresa M; Heng, Henry H Q; Shivdasani, Ramesh A; Ahmed, Rafi; Andrews, Nancy C; Blank, Volker

    2004-04-01

    Cap'n'collar (CNC) family basic leucine zipper transcription factors play crucial roles in the regulation of mammalian gene expression and development. To determine the in vivo function of the CNC protein Nrf3 (NF-E2-related factor 3), we generated mice deficient in this transcription factor. We performed targeted disruption of two Nrf3 exons coding for CNC homology, basic DNA-binding, and leucine zipper dimerization domains. Nrf3 null mice developed normally and revealed no obvious phenotypic differences compared to wild-type animals. Nrf3(-/-) mice were fertile, and gross anatomy as well as behavior appeared normal. The mice showed normal age progression and did not show any apparent additional phenotype during their life span. We observed no differences in various blood parameters and chemistry values. We infected wild-type and Nrf3(-/-) mice with acute lymphocytic choriomeningitis virus and found no differences in these animals with respect to their number of virus-specific CD8 and CD4 T cells as well as their B-lymphocyte response. To determine whether the mild phenotype of Nrf3 null animals is due to functional redundancy, we generated mice deficient in multiple CNC factors. Contrary to our expectations, an absence of Nrf3 does not seem to cause additional lethality in compound Nrf3(-/-)/Nrf2(-/-) and Nrf3(-/-)/p45(-/-) mice. We hypothesize that the role of Nrf3 in vivo may become apparent only after appropriate challenge to the mice.

  2. Chronic Endurance Exercise Impairs Cardiac Structure and Function in Middle-Aged Mice with Impaired Nrf2 Signaling

    PubMed Central

    Shanmugam, Gobinath; Narasimhan, Madhusudhanan; Conley, Robbie L.; Sairam, Thiagarajan; Kumar, Ashutosh; Mason, Ronald P.; Sankaran, Ramalingam; Hoidal, John R.; Rajasekaran, Namakkal S.

    2017-01-01

    Nuclear factor erythroid 2 related factor 2 (Nrf2) signaling maintains the redox homeostasis and its activation is shown to suppress cardiac maladaptation. Earlier we reported that acute endurance exercise (2 days) evoked antioxidant cytoprotection in young WT animals but not in aged WT animals. However, the effect of repeated endurance exercise during biologic aging (WT) characterized by an inherent deterioration in Nrf2 signaling and pathological aging (pronounced oxidative susceptibility—Nrf2 absence) in the myocardium remains elusive. Thus, the purpose of our study was to determine the effect of chronic endurance exercise-induced cardiac adaptation in aged mice with and without Nrf2. Age-matched WT and Nrf2-null mice (Nrf2−/−) (>22 months) were subjected to 6 weeks chronic endurance exercise (25 meter/min, 12% grade). The myocardial redox status was assessed by expression of antioxidant defense genes and proteins along with immunochemical detection of DMPO-radical adduct, GSH-NEM, and total ubiquitination. Cardiac functions were assessed by echocardiography and electrocardiogram. At sedentary state, loss of Nrf2 resulted in significant downregulation of antioxidant gene expression (Nqo1, Ho1, Gclm, Cat, and Gst-α) with decreased GSH-NEM immuno-fluorescence signals. While Nrf2−/− mice subjected to CEE showed an either similar or more pronounced reduction in the transcript levels of Gclc, Nqo1, Gsr, and Gst-α in relation to WT littermates. In addition, the hearts of Nrf2−/− on CEE showed a substantial reduction in specific antioxidant proteins, G6PD and CAT along with decreased GSH, a pronounced increase in DMPO-adduct and the total ubiquitination levels. Further, CEE resulted in a significant upregulation of hypertrophy genes (Anf, Bnf, and β-Mhc) (p < 0.05) in the Nrf2−/− hearts in relation to WT mice. Moreover, the aged Nrf2−/− mice exhibited a higher degree of cardiac remodeling in association with a significant decrease in fractional

  3. Berberine activates Nrf2 nuclear translocation and inhibits apoptosis induced by high glucose in renal tubular epithelial cells through a phosphatidylinositol 3-kinase/Akt-dependent mechanism.

    PubMed

    Zhang, Xiuli; Liang, Dan; Lian, Xu; Jiang, Yan; He, Hui; Liang, Wei; Zhao, Yue; Chi, Zhi-Hong

    2016-06-01

    Apoptosis of tubular epithelial cells is a major feature of diabetic kidney disease, and hyperglycemia triggers the generation of free radicals and oxidant stress in tubular cells. Berberine (BBR) is identified as a potential anti-diabetic herbal medicine due to its beneficial effects on insulin sensitivity, glucose metabolism and glycolysis. In this study, the underlying mechanisms involved in the protective effects of BBR on high glucose-induced apoptosis were explored using cultured renal tubular epithelial cells (NRK-52E cells) and human kidney proximal tubular cell line (HK-2 cells). We identified the pivotal role of phosphatidylinositol 3-kinase (PI3K)/Akt in BBR cellular defense mechanisms and revealed the novel effect of BBR on nuclear factor (erythroid-derived 2)-related factor-2 (Nrf2) and heme oxygenase (HO)-1 in NRK-52E and HK-2 cells. BBR attenuated reactive oxygen species production, antioxidant defense (GSH and SOD) and oxidant-sensitive proteins (Nrf2 and HO-1), which also were blocked by LY294002 (an inhibitor of PI3K) in HG-treated NRK-52E and HK-2 cells. Furthermore, BBR improved mitochondrial function by increasing mitochondrial membrane potential. BBR-induced anti-apoptotic function was demonstrated by decreasing apoptotic proteins (cytochrome c, Bax, caspase3 and caspase9). All these findings suggest that BBR exerts the anti-apoptosis effects through activation of PI3K/Akt signal pathways and leads to activation of Nrf2 and induction of Nrf2 target genes, and consequently protecting the renal tubular epithelial cells from HG-induced apoptosis.

  4. Mechanisms of activation of the transcription factor Nrf2 by redox stressors, nutrient cues, and energy status and the pathways through which it attenuates degenerative disease.

    PubMed

    Tebay, Lauren E; Robertson, Holly; Durant, Stephen T; Vitale, Steven R; Penning, Trevor M; Dinkova-Kostova, Albena T; Hayes, John D

    2015-11-01

    Nuclear factor-erythroid 2 p45-related factor 2 (Nrf2) regulates the basal and stress-inducible expression of a battery of genes encoding key components of the glutathione-based and thioredoxin-based antioxidant systems, as well as aldo-keto reductase, glutathione S-transferase, and quinone oxidoreductase-1 drug-metabolizing isoenzymes along with multidrug-resistance-associated efflux pumps. It therefore plays a pivotal role in both intrinsic resistance and cellular adaptation to reactive oxygen species (ROS) and xenobiotics. Activation of Nrf2 can, however, serve as a double-edged sword because some of the genes it induces may contribute to chemical carcinogenesis by promoting futile redox cycling of polycyclic aromatic hydrocarbon metabolites or confer resistance to chemotherapeutic drugs by increasing the expression of efflux pumps, suggesting its cytoprotective effects will vary in a context-specific fashion. In addition to cytoprotection, Nrf2 also controls genes involved in intermediary metabolism, positively regulating those involved in NADPH generation, purine biosynthesis, and the β-oxidation of fatty acids, while suppressing those involved in lipogenesis and gluconeogenesis. Nrf2 is subject to regulation at multiple levels. Its ability to orchestrate adaptation to oxidants and electrophiles is due principally to stress-stimulated modification of thiols within one of its repressors, the Kelch-like ECH-associated protein 1 (Keap1), which is present in the cullin-3 RING ubiquitin ligase (CRL) complex CRLKeap1. Thus modification of Cys residues in Keap1 blocks CRLKeap1 activity, allowing newly translated Nrf2 to accumulate rapidly and induce its target genes. The ability of Keap1 to repress Nrf2 can be attenuated by p62/sequestosome-1 in a mechanistic target of rapamycin complex 1 (mTORC1)-dependent manner, thereby allowing refeeding after fasting to increase Nrf2-target gene expression. In parallel with repression by Keap1, Nrf2 is also repressed by

  5. Mechanisms of activation of the transcription factor Nrf2 by redox stressors, nutrient cues, and energy status and the pathways through which it attenuates degenerative disease

    PubMed Central

    Tebay, Lauren E.; Robertson, Holly; Durant, Stephen T.; Vitale, Steven R.; Penning, Trevor M.; Dinkova-Kostova, Albena T.; Hayes, John D.

    2015-01-01

    Nuclear factor-erythroid 2 p45-related factor 2 (Nrf2) regulates the basal and stress-inducible expression of a battery of genes encoding key components of the glutathione-based and thioredoxin-based anti-oxidant systems, as well as aldo-keto reductase, glutathione S-transferase, and NAD(P)H:quinone oxi-doreductase-1 drug-metabolizing isoenzymes along with multidrug-resistance-associated efflux pumps. It therefore plays a pivotal role in both intrinsic resistance and cellular adaptation to reactive oxygen species (ROS) and xenobiotics. Activation of Nrf2 can, however, serve as a double-edged sword because some of the genes it induces may contribute to chemical carcinogenesis by promoting futile redox cycling of polycyclic aromatic hydrocarbon metabolites or confer resistance to chemotherapeutic drugs by increasing the expression of efflux pumps, suggesting its cytoprotective effects will vary in a context-specific fashion. In addition to cytoprotection, Nrf2 also controls genes involved in intermediary metabolism, positively regulating those involved in NADPH generation, purine biosynthesis, and the β-oxidation of fatty acids, while suppressing those involved in lipogenesis and gluconeogenesis. Nrf2 is subject to regulation at multiple levels. Its ability to orchestrate adaptation to oxidants and electrophiles is due principally to stress-stimulated modification of thiols within one of its repressors, the Kelch-like ECH-associated protein 1 (Keap1), which is present in the cullin-3 RING ubiquitin ligase (CRL) complex CRLKeap1. Thus modification of Cys residues in Keap1 blocks CRLKeap1 activity, allowing newly translated Nrf2 to accumulate rapidly and induce its target genes. The ability of Keap1 to repress Nrf2 can be attenuated by p62/sequestosome-1 in a mechanistic target of rapamycin complex 1 (mTORC1)-depen-dent manner, thereby allowing refeeding after fasting to increase Nrf2-target gene expression. In parallel with repression by Keap1, Nrf2 is also repressed

  6. Keap1-Nrf2 Signaling: A Target for Cancer Prevention by Sulforaphane

    PubMed Central

    Kensler, Thomas W; Egner, Patricia A; Agyeman, Abena S.; Visvanathan, Kala; Groopman, John D; Chen, Jian-Guo; Chen, Tao-Yang; Fahey, Jed W; Talalay, Paul

    2013-01-01

    Sulforaphane is a promising agent under preclinical evaluation in many models of disease prevention. This bioactive phytochemical affects many molecular targets in cellular and animal models; however, amongst the most sensitive is Keap1, a key sensor for the adaptive stress response system regulated through the transcription factor Nrf2. Keap1 is a sulfhydryl-rich protein that represses Nrf2 signaling by facilitating the poly ubiquitination of Nrf2 thereby enabling its subsequent proteasomal degradation. Interaction of sulforaphane with Keap1 disrupts this function and allows for nuclear accumulation of Nrf2 and activation of its transcriptional program. Enhanced transcription of Nrf2 target genes provokes a strong cytoprotective response that enhances resistance to carcinogenesis and other diseases mediated by exposures to electrophiles and oxidants. Clinical evaluation of sulforaphane has been largely conducted by utilizing preparations of broccoli or broccoli sprouts rich in either sulforaphane or its precursor form in plants, a stable β-thioglucose conjugate termed glucoraphanin. We have conducted a series of clinical trials in Qidong, China, a region where exposures to food- and air-borne carcinogens has been considerable, to evaluate the suitability of broccoli sprout beverages, rich in either glucoraphanin (GRR) or sulforaphane SFR or both for their bioavailability, tolerability and pharmacodynamic action in population-based interventions. Results from these clinical trials indicate that interventions with well characterized preparations of broccoli sprouts may enhance the detoxication of aflatoxins and air-borne toxins, which may in turn attenuate their associated health risks, including cancer, in exposed individuals. PMID:22752583

  7. Antioxidant axis Nrf2-keap1-ARE in inhibition of alcoholic liver fibrosis by IL-22

    PubMed Central

    Ni, Ya-Hui; Huo, Li-Juan; Li, Ting-Ting

    2017-01-01

    AIM To explore the effect of interleukin (IL)-22 on in vitro model of alcoholic liver fibrosis hepatic stellate cells (HSCs), and whether this is related to regulation of Nrf2-keap1-ARE. METHODS HSC-T6 cells were incubated with 25, 50, 100, 200 and 400 μmol/L acetaldehyde. After 24 and 48 h, 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide (MTT) assay was used to detect proliferation of HSCs to choose the best concentration and action time. We used the optimal concentration of acetaldehyde (200 μmol/L) to stimulate HSCs for 24 h, and treated the cells with a final concentration of 10, 20 or 50 ng/mL IL-22. The cell proliferation rate was detected by MTT assay. The cell cycle was analyzed by flow cytometry. The expression of nuclear factor-related factor (Nrf)2 and α-smooth muscle antigen was detected by western blotting and immunocytochemistry. The levels of malondialdehyde (MDA) and glutathione (GSH) were measured by spectrophotometry. RESULTS In the MTT assay, when HSCs were incubated with acetaldehyde, activity and proliferation were higher than in the control group, and were most obvious after 48 h treatment with 200 μmol/L acetaldehyde. The number of cells in G0/G1 phases was decreased and the number in S phase was increased in comparison with the control group. When treated with different concentrations of IL-22, HSC-T6 cell activity and proliferation rate were markedly decreased in a dose-dependent manner, and cell cycle progression was arrested from G1 to S phase. Western blotting and immunocytochemistry demonstrated that expression of Nrf2 total protein was not significantly affected. Expression of Nrf2 nuclear protein was low in the control group, increased slightly in the model group (or acetaldehyde-stimulated group), and increased more obviously in the IL-22 intervention groups. The levels of MDA and GSH in the model group were significantly enhanced in comparison with those in the control group. In cells treated with IL-22, the MDA

  8. Sulforaphane induces Nrf2 target genes and attenuates inflammatory gene expression in microglia from brain of young adult and aged mice.

    PubMed

    Townsend, Brigitte E; Johnson, Rodney W

    2016-01-01

    Increased neuroinflammation and oxidative stress resulting from heightened microglial activation are associated with age-related cognitive impairment. The objectives of this study were to examine the effects of the bioactive sulforaphane (SFN) on the nuclear factor E2-related factor 2 (Nrf2) pathway in BV2 microglia and primary microglia, and to evaluate proinflammatory cytokine expression in lipopolysaccharide (LPS)-stimulated primary microglia from adult and aged mice. BV2 microglia and primary microglia isolated from young adult and aged mice were treated with SFN and LPS. Changes in Nrf2 activity, expression of Nrf2 target genes, and levels of proinflammatory markers were assessed by quantitative PCR and immunoassay. SFN increased Nrf2 DNA-binding activity and upregulated Nrf2 target genes in BV2 microglia, while reducing LPS-induced interleukin (IL-)1β, IL-6, and inducible nitric oxide synthase (iNOS). In primary microglia from adult and aged mice, SFN increased expression of Nrf2 target genes and attenuated IL-1β, IL-6, and iNOS induced by LPS. These data indicate that SFN is a potential beneficial supplement that may be useful for reducing microglial mediated neuroinflammation and oxidative stress associated with aging. Copyright © 2015 Elsevier Inc. All rights reserved.

  9. The antioxidant and anti-inflammatory activities of tocopherols are independent of Nrf2 in mice.

    PubMed

    Li, Guangxun; Lee, Mao-Jung; Liu, Anna Ba; Yang, Zhihong; Lin, Yong; Shih, Weichung Joe; Yang, Chung S

    2012-04-01

    The present study investigated the antioxidant and anti-inflammatory actions of tocopherols in mice and determined whether the nuclear factor (erythroid-derived 2)-like 2 (Nrf2) is involved in these activities. A mixture of tocopherols (γ-TmT) that is rich in γ-tocopherol was used. Nrf2 knockout (Nrf2 -/-) and wild-type mice were maintained on 0.03, 0.1, or 0.3% γ-TmT-enriched diet starting 2 weeks before the administration of dextran sulfate sodium (DSS) in drinking water (for 1 week, to induce colonic inflammation), until the termination of the experiment at 3 days after the DSS treatment. Dietary γ-TmT dose dependently lowered the levels of 8-oxo-deoxyguanosine, nitrotyrosine, inflammation index, and leukocyte infiltration in colon tissues, as well as 8-isoprostane and prostaglandin E2 in the serum, in both Nrf2 (-/-) and wild-type mice. No significant difference on the inhibitory actions of γ-TmT between the Nrf2 (-/-) and the wild-type mice was observed. The γ-TmT treatment significantly increased the serum levels of γ- and δ-tocopherols. Interestingly, the serum levels of tocopherol metabolites, specifically the γ- and δ-forms of carboxymethylbutyl hydroxychroman and carboxyethyl hydroxychroman, in Nrf2 (-/-) mice were significantly higher than those in wild-type mice. These findings suggest that the antioxidant and anti-inflammatory activities of γ-TmT in the colon are mostly due to the direct action of tocopherols in trapping reactive oxygen and nitrogen species, independent of the antioxidant enzymes and anti-inflammatory proteins that are regulated by Nrf2; however, Nrf2 knockout appears to affect the serum levels of tocopherol metabolites. Copyright © 2011. Published by Elsevier Inc.

  10. CSF Nrf2 and HSPA8 in Parkinson's disease patients with and without LRRK2 gene mutations.

    PubMed

    Loeffler, David A; Smith, Lynnae M; Coffey, Mary P; Aasly, Jan O; LeWitt, Peter A

    2016-03-01

    Leucine-rich repeat kinase 2 (LRRK2) gene mutations are the most common genetic cause of Parkinson's disease (PD). CSF specimens from LRRK2 + PD patients and healthy LRRK2 mutation carriers are, therefore, useful for biomarker studies. This study examined the hypothesis that differences are present between subjects with sporadic PD (sPD), PD carriers of LRRK2 mutations (LRRK2 + PD), healthy control subjects lacking LRRK2 mutations (CTL), and LRRK2 mutation-carrying healthy controls (LRRK2 + CTL) for CSF concentrations of six potential PD biomarkers. Two of these proteins, nuclear factor (erythroid-derived 2)-like 2 ("Nrf2") and heat shock 70 kDa protein 8 ("HSPA8"), were detected in preliminary ELISAs, then measured in a larger cohort (60 sPD, 10 LRRK2 + PD, 23 CTL, 31 LRRK2 + CTL). No statistically significant differences were found between the groups (Nrf2 p = 0.13, HSPA8 p = 0.21). Nrf2 concentrations in LRRK2 + PD subjects were strongly positively associated with Unified Parkinson's Disease Rating Scale (UPDRS) total and motor scores [Spearman rho = 0.77 (p = 0.012) and 0.83 (p = 0.005)] and negatively associated with Montreal Cognitive Assessment (MoCA) scores (rho = -0.57; p = 0.11). Partial correlation coefficient calculations indicated that disease duration contributed to the associations of Nrf2 levels with UPDRS scores and with MoCA scores in this group. While CSF Nrf2 and HSPA8 do not appear to offer diagnostic biomarkers for PD, the associations between Nrf2 levels and UPDRS scores in LRRK2 + PD patients merit further investigation.

  11. Piper betle Induced Cytoprotective Genes and Proteins via the Nrf2/ARE Pathway in Aging Mice.

    PubMed

    Aliahmat, Nor Syahida; Abdul Sani, Nur Fathiah; Wan Hasan, Wan Nuraini; Makpol, Suzana; Wan Ngah, Wan Zurinah; Mohd Yusof, Yasmin Anum

    2016-01-01

    The objective of this study was to elucidate the underlying antioxidant mechanism of aqueous extract of Piper betle (PB) in aging rats. The nuclear factor erythroid 2-related factor 2 (Nrf2)/ARE pathway involving phase II detoxifying and antioxidant enzymes plays an important role in the antioxidant system by reducing electrophiles and reactive oxygen species through induction of phase II enzymes and proteins. Genes and proteins of phase II detoxifying antioxidant enzymes were analyzed by QuantiGenePlex 2.0 Assay and Western blot analysis. PB significantly induced genes and proteins of phase II and antioxidant enzymes, NAD(P)H quinone oxidoreductase 1, and catalase in aging mice (p < 0.05). The expression of these enzymes were stimulated via translocation of Nrf2 into the nucleus, indicating the involvement of ARE, a cis-acting motif located in the promoter region of nearly all phase II genes. PB was testified for the first time to induce cytoprotective genes through the Nrf2/ARE signaling pathway, thus unraveling the antioxidant mechanism of PB during the aging process. © 2016 S. Karger AG, Basel.

  12. The Crosstalk Between Nrf2 and AMPK Signal Pathways Is Important for the Anti-Inflammatory Effect of Berberine in LPS-Stimulated Macrophages and Endotoxin-Shocked Mice

    PubMed Central

    Mo, Chunfen; Wang, Ling; Zhang, Jie; Numazawa, Satoshi; Tang, Hong; Tang, Xiaoqiang; Han, XiaoJuan; Li, Junhong; Yang, Ming; Wang, Zhe; Wei, Dandan

    2014-01-01

    Abstract Aims: The response of AMP-activated protein kinase (AMPK) to oxidative stress has been recently reported but the downstream signals of this response are largely unknown. Meanwhile, the upstream events for the activation of nuclear factor erythroid-2-related factor-2 (Nrf2), a critical transcriptional activator for antioxidative responses, remain unclear. In the present study, we investigated the relationship between AMPK and Nrf2 signal pathways in lipopolysaccharide (LPS)-triggered inflammatory system, in which berberine (BBR), a known AMPK activator, was used for inflammation suppression. Results and Innovation: In inflammatory macrophages, BBR attenuated LPS-induced expression of inflammatory genes (inducible nitric oxide synthase [iNOS], cyclooxygenase-2 [COX2], interleukin [IL]-6), and the generation of nitric oxide and reactive oxygen species, but increased the transcription of Nrf2-targeted antioxidative genes (NADPH quinone oxidoreductase-1 [NQO-1], heme oxygenase-1 [HO-1]), as well as the nuclear localization and phosphorylation of Nrf2 protein. Importantly, we found BBR-induced activation of Nrf2 is AMPK-dependent, as either pharmacologically or genetically inactivating AMPK blocked the activation of Nrf2. Consistent with in vitro experiments, BBR down-regulated the expression of proinflammatory genes but upregulated those of Nrf2-targeted genes in lungs of LPS-injected mice, and these effects were attenuated in Nrf2-deficient mice. Moreover, the effect of BBR on survival time extension and plasma redox regulation in endotoxin-shocked mice was largely weakened when Nrf2-depleted. Conclusions: Our results demonstrate convergence between AMPK and Nrf2 pathways and this intersection is essential for anti-inflammatory effect of BBR in LPS-stimulated macrophages and endotoxin-shocked mice. Uncovering this intersection is significant for understanding the relationship between energy homeostasis and antioxidative responses and may be beneficial for

  13. Escin activates AKT-Nrf2 signaling to protect retinal pigment epithelium cells from oxidative stress

    DOE Office of Scientific and Technical Information (OSTI.GOV)

    Wang, Kaijun; Zhejiang Provincial Key Lab of Ophthalmology, Hangzhou; Jiang, Yiqian

    Here we explored the anti-oxidative and cytoprotective potentials of escin, a natural triterpene-saponin, against hydrogen peroxide (H{sub 2}O{sub 2}) in retinal pigment epithelium (RPE) cells. We showed that escin remarkably attenuated H{sub 2}O{sub 2}-induced death and apoptosis of established (ARPE-19) and primary murine RPE cells. Meanwhile, ROS production and lipid peroxidation by H{sub 2}O{sub 2} were remarkably inhibited by escin. Escin treatment in RPE cells resulted in NF-E2-related factor 2 (Nrf2) signaling activation, evidenced by transcription of anti-oxidant-responsive element (ARE)-regulated genes, including HO-1, NQO-1 and SRXN-1. Knockdown of Nrf2 through targeted shRNAs/siRNAs alleviated escin-mediated ARE gene transcription, and almost abolishedmore » escin-mediated anti-oxidant activity and RPE cytoprotection against H{sub 2}O{sub 2}. Reversely, escin was more potent against H{sub 2}O{sub 2} damages in Nrf2-over-expressed ARPE-19 cells. Further studies showed that escin-induced Nrf2 activation in RPE cells required AKT signaling. AKT inhibitors (LY294002 and perifosine) blocked escin-induced AKT activation, and dramatically inhibited Nrf2 phosphorylation, its cytosol accumulation and nuclear translocation in RPE cells. Escin-induced RPE cytoprotection against H{sub 2}O{sub 2} was also alleviated by the AKT inhibitors. Together, these results demonstrate that escin protects RPE cells from oxidative stress possibly through activating AKT-Nrf2 signaling.« less

  14. The Nrf2-inducers tanshinone I and dihydrotanshinone protect human skin cells and reconstructed human skin against solar simulated UV☆

    PubMed Central

    Tao, Shasha; Justiniano, Rebecca; Zhang, Donna D.; Wondrak, Georg T.

    2013-01-01

    Exposure to solar ultraviolet (UV) radiation is a causative factor in skin photocarcinogenesis and photoaging, and an urgent need exists for improved strategies for skin photoprotection. The redox-sensitive transcription factor Nrf2 (nuclear factor-E2-related factor 2), a master regulator of the cellular antioxidant defense against environmental electrophilic insult, has recently emerged as an important determinant of cutaneous damage from solar UV, and the concept of pharmacological activation of Nrf2 has attracted considerable attention as a novel approach to skin photoprotection. In this study, we examined feasibility of using tanshinones, a novel class of phenanthrenequinone-based cytoprotective Nrf2 inducers derived from the medicinal plant Salvia miltiorrhiza, for protection of cultured human skin cells and reconstructed human skin against solar simulated UV. Using a dual luciferase reporter assay in human Hs27 dermal fibroblasts pronounced transcriptional activation of Nrf2 by four major tanshinones [tanshinone I (T-I), dihydrotanshinone (DHT), tanshinone IIA (T-II-A) and cryptotanshinone (CT)] was detected. In fibroblasts, the more potent tanshinones T-I and DHT caused a significant increase in Nrf2 protein half-life via blockage of ubiquitination, ultimately resulting in upregulated expression of cytoprotective Nrf2 target genes (GCLC, NQO1) with the elevation of cellular glutathione levels. Similar tanshinone-induced changes were also observed in HaCaT keratinocytes. T-I and DHT pretreatment caused significant suppression of skin cell death induced by solar simulated UV and riboflavin-sensitized UVA. Moreover, feasibility of tanshinone-based cutaneous photoprotection was tested employing a human skin reconstruct exposed to solar simulated UV (80 mJ/cm2 UVB; 1.53 J/cm2 UVA). The occurrence of markers of epidermal solar insult (cleaved procaspase 3, pycnotic nuclei, eosinophilic cytoplasm, acellular cavities) was significantly attenuated in DHT

  15. MOLECULAR MECHANISM OF HUMAN NRF2 ACTIVATION AND DEGRADATION: ROLE OF SEQUENTIAL PHOSPHORYLATION BY PROTEIN KINASE CK2

    PubMed Central

    Pi, Jingbo; Bai, Yushi; Reece, Jeffrey M.; Williams, Jason; Liu, Dianxin; Freeman, Michael L.; Fahl, William E.; Shugar, David; Liu, Jie; Qu, Wei; Collins, Sheila; Waalkes, Michael P.

    2007-01-01

    Nrf2 is a key transcription factor in the cellular response to oxidative stress. In this study we first identify two phosphorylated forms of endogenous human Nrf2 after chemically-induced oxidative stress and provide evidence that protein kinase CK2-mediated sequential phosphorylation plays potential role in Nrf2 activation and degradation. Human Nrf2 has a predicted molecular mass of 66 kDa. However, immunoblots showed that two bands at 98 and 118 kDa, which are identified as phosphorylated forms, are increased in response to Nrf2 inducers. In addition, human Nrf2 was found to be a substrate for CK2 which mediated two steps of phosphorylation, resulting in two forms of Nrf2 migrating with differing Mr at 98 kDa (Nrf2–98) and 118 kDa (Nrf2–118). Our results support a role in which calmodulin binding regulates CK2 activity, in that cold (25 °C) in Ca2+-free media (cold/Ca2+-free) decreased both cellular calcium levels and CK2-calmodulin binding and induced Nrf2–118 formation, the latter of which was prevented by CK2 specific inhibitors. Gel-shift assays showed that the Nrf2–118 generated under cold/Ca2+-free conditions does not bind to the antioxidant response element, indicating that Nrf2–98 has transcriptional activity. In contrast, Nrf2–118 is more susceptible to degradation. These results provide evidence for phosphorylation by CK2 as a critical controlling factor in Nrf2-mediated cellular antioxidant response. PMID:17512459

  16. Upregulation of transcription factor NRF2-mediated oxidative stress response pathway in rat brain under short-term chronic hypobaric hypoxia.

    PubMed

    Sethy, Niroj Kumar; Singh, Manjulata; Kumar, Rajesh; Ilavazhagan, Govindasamy; Bhargava, Kalpana

    2011-03-01

    Exposure to high altitude (and thus hypobaric hypoxia) induces electrophysiological, metabolic, and morphological modifications in the brain leading to several neurological clinical syndromes. Despite the known fact that hypoxia episodes in brain are a common factor for many neuropathologies, limited information is available on the underlying cellular and molecular mechanisms. In this study, we investigated the temporal effect of short-term (0-12 h) chronic hypobaric hypoxia on global gene expression of rat brain followed by detailed canonical pathway analysis and regulatory network identification. Our analysis revealed significant alteration of 33, 17, 53, 81, and 296 genes (p < 0.05, <1.5-fold) after 0.5, 1, 3, 6, and 12 h of hypoxia, respectively. Biological processes like regulation, metabolic, and transport pathways are temporally activated along with anti- and proinflammatory signaling networks like PI3K/AKT, NF-κB, ERK/MAPK, IL-6 and IL-8 signaling. Irrespective of exposure durations, nuclear factor (erythroid-derived 2)-like 2 (NRF2)-mediated oxidative stress response pathway and genes were detected at all time points suggesting activation of NRF2-ARE antioxidant defense system. The results were further validated by assessing the expression levels of selected genes in temporal as well as brain regions with quantitative RT-PCR and western blot. In conclusion, our whole brain approach with temporal monitoring of gene expression patterns during hypobaric hypoxia has resulted in (1) deciphering sequence of pathways and signaling networks activated during onset of hypoxia, and (2) elucidation of NRF2-orchestrated antioxidant response as a major intrinsic defense mechanism. The results of this study will aid in better understanding and management of hypoxia-induced brain pathologies.

  17. NRF2 Mediates Neuroblastoma Proliferation and Resistance to Retinoic Acid Cytotoxicity in a Model of In Vitro Neuronal Differentiation.

    PubMed

    de Miranda Ramos, Vitor; Zanotto-Filho, Alfeu; de Bittencourt Pasquali, Matheus Augusto; Klafke, Karina; Gasparotto, Juciano; Dunkley, Peter; Gelain, Daniel Pens; Moreira, José Cláudio Fonseca

    2016-11-01

    Retinoic acid (RA) morphogenetic properties have been used in different kinds of therapies, from neurodegenerative disorders to some types of cancer such as promyelocytic leukemia and neuroblastoma. However, most of the pathways responsible for RA effects remain unknown. To investigate such pathways, we used a RA-induced differentiation model in the human neuroblastoma cells, SH-SY5Y. Our data showed that n-acetyl-cysteine (NAC) reduced cells' proliferation rate and increased cells' sensitivity to RA toxicity. Simultaneously, NAC pre-incubation attenuated nuclear factor erythroid 2-like factor 2 (NRF2) activation by RA. None of these effects were obtained with Trolox ® as antioxidant, suggesting a cysteine signalization by RA. NRF2 knockdown increased cell sensibility to RA after 96 h of treatment and diminished neuroblastoma proliferation rate. Conversely, NRF2 overexpression limited RA anti-proliferative effects and increased cell proliferation. In addition, a rapid and non-genomic activation of the ERK 1/2 and PI3K/AKT pathways revealed to be equally required to promote NRF2 activation and necessary for RA-induced differentiation. Together, we provide data correlating NRF2 activity with neuroblastoma proliferation and resistance to RA treatments; thus, this pathway could be a potential target to optimize neuroblastoma chemotherapeutic response as well as in vitro neuronal differentiation protocols.

  18. Hyperactivation of Nrf2 in early tubular development induces nephrogenic diabetes insipidus

    PubMed Central

    Suzuki, Takafumi; Seki, Shiori; Hiramoto, Keiichiro; Naganuma, Eriko; Kobayashi, Eri H.; Yamaoka, Ayaka; Baird, Liam; Takahashi, Nobuyuki; Sato, Hiroshi; Yamamoto, Masayuki

    2017-01-01

    NF-E2-related factor-2 (Nrf2) regulates cellular responses to oxidative and electrophilic stress. Loss of Keap1 increases Nrf2 protein levels, and Keap1-null mice die of oesophageal hyperkeratosis because of Nrf2 hyperactivation. Here we show that deletion of oesophageal Nrf2 in Keap1-null mice allows survival until adulthood, but the animals develop polyuria with low osmolality and bilateral hydronephrosis. This phenotype is caused by defects in water reabsorption that are the result of reduced aquaporin 2 levels in the kidney. Renal tubular deletion of Keap1 promotes nephrogenic diabetes insipidus features, confirming that Nrf2 activation in developing tubular cells causes a water reabsorption defect. These findings suggest that Nrf2 activity should be tightly controlled during development in order to maintain renal homeostasis. In addition, tissue-specific ablation of Nrf2 in Keap1-null mice might create useful animal models to uncover novel physiological functions of Nrf2. PMID:28233855

  19. Pterostilbene protects against UVB-induced photo-damage through a phosphatidylinositol-3-kinase-dependent Nrf2/ARE pathway in human keratinocytes.

    PubMed

    Li, Huaping; Jiang, Na; Liang, Bihua; Liu, Qing; Zhang, Erting; Peng, Liqian; Deng, Huiyan; Li, Runxiang; Li, Zhenjie; Zhu, Huilan

    2017-11-01

    Ultraviolet B (UVB) irradiation is the initial etiological factor for various skin disorders, including erythema, sunburn, photoaging, and photocarcinogenesis. Pterostilbene (Pter) displayed remarkable antioxidant, anti-inflammatory, and anticarcinogenic activities. This study aimed to investigate the effective mechanism of Pter against UVB-induced photodamage in immortalized human keratinocytes. Human keratinocytes were pretreated with Pter (5 and 10 μM) for 24 h prior to UVB irradiation (300 mJ/cm 2 ). Harvested cells were analyzed by MTT, DCFH-DA, comet, western blotting, luciferase promoter, small interference RNA transfection, and quantitative real-time polymerase chain reaction assay. Pter significantly attenuated UVB-induced cell death and reactive oxygen species (ROS) generation, and effectively increased nuclear translocation of NF-E2-related factor-2 (Nrf2), expression of Nrf2-dependent antioxidant enzymes, and DNA repair activity. Moreover, the protective effects of Pter were abolished by small interference RNA-mediated Nrf2 silencing. Furthermore, Pter was also found to induce the phosphorylation of Nrf2 and the known phosphatidylinositol-3-kinase (PI3K) phosphorylated kinase, Akt. The specific inhibitor of PI3K, LY294002, successfully abrogated Pter-induced Nrf2 phosphorylation, activation of Nrf2-antioxidant response element pathway, ROS scavenging ability, and DNA repair activity. The present study indicated that Pter effectively protected against UVB-induced photodamage by increasing endogenous defense mechanisms, scavenging UVB-induced ROS, and aiding in damaged DNA repair through a PI3K-dependent activation of Nrf2/ARE pathway.

  20. Experimental Nonalcoholic Steatohepatitis and Liver Fibrosis Are Ameliorated by Pharmacologic Activation of Nrf2 (NF-E2 p45-Related Factor 2).

    PubMed

    Sharma, Ritu S; Harrison, David J; Kisielewski, Dorothy; Cassidy, Diane M; McNeilly, Alison D; Gallagher, Jennifer R; Walsh, Shaun V; Honda, Tadashi; McCrimmon, Rory J; Dinkova-Kostova, Albena T; Ashford, Michael L J; Dillon, John F; Hayes, John D

    2018-03-01

    Nonalcoholic steatohepatitis (NASH) is associated with oxidative stress. We surmised that pharmacologic activation of NF-E2 p45-related factor 2 (Nrf2) using the acetylenic tricyclic bis(cyano enone) TBE-31 would suppress NASH because Nrf2 is a transcriptional master regulator of intracellular redox homeostasis. Nrf2 +/+ and Nrf2 -/- C57BL/6 mice were fed a high-fat plus fructose (HFFr) or regular chow diet for 16 weeks or 30 weeks, and then treated for the final 6 weeks, while still being fed the same HFFr or regular chow diets, with either TBE-31 or dimethyl sulfoxide vehicle control. Measures of whole-body glucose homeostasis, histologic assessment of liver, and biochemical and molecular measurements of steatosis, endoplasmic reticulum (ER) stress, inflammation, apoptosis, fibrosis, and oxidative stress were performed in livers from these animals. TBE-31 treatment reversed insulin resistance in HFFr-fed wild-type mice, but not in HFFr-fed Nrf2-null mice. TBE-31 treatment of HFFr-fed wild-type mice substantially decreased liver steatosis and expression of lipid synthesis genes, while increasing hepatic expression of fatty acid oxidation and lipoprotein assembly genes. Also, TBE-31 treatment decreased ER stress, expression of inflammation genes, and markers of apoptosis, fibrosis, and oxidative stress in the livers of HFFr-fed wild-type mice. By comparison, TBE-31 did not decrease steatosis, ER stress, lipogenesis, inflammation, fibrosis, or oxidative stress in livers of HFFr-fed Nrf2-null mice. Pharmacologic activation of Nrf2 in mice that had already been rendered obese and insulin resistant reversed insulin resistance, suppressed hepatic steatosis, and mitigated against NASH and liver fibrosis, effects that we principally attribute to inhibition of ER, inflammatory, and oxidative stress.

  1. RS9, a novel Nrf2 activator, attenuates light-induced death of cells of photoreceptor cells and Müller glia cells.

    PubMed

    Inoue, Yuki; Shimazawa, Masamitsu; Noda, Yasuhiro; Nagano, Ryota; Otsuka, Tomohiro; Kuse, Yoshiki; Nakano, Yukimichi; Tsuruma, Kazuhiro; Nakagami, Yasuhiro; Hara, Hideaki

    2017-06-01

    The retina is highly sensitive to oxidative stress because of its high consumption of oxygen associated with the phototransductional processes. Recent findings have suggested that oxidative stress is involved in the pathology of age-related macular degeneration, a progressive degeneration of the central retina. A well-known environmental risk factor is light exposure, as excessive and continuous light exposure can damage photoreceptors. Nuclear factor-erythroid 2-related factor 2 (Nrf2) is a transcriptional factor that controls antioxidative responses and phase 2 enzymes. Thus, we hypothesized that RS9, a specific activator of Nrf2, decreases light-induced retinal cell death in vivo and in vitro. Nrf2 was detected in the nucleus of the 661W cells exposed to RS9 and also after light exposure, and the Nrf2-antioxidant response element binding was increased in 661W cells after exposure to RS9. Consequentially, the expression of the phase 2 enzyme's mRNAs of Ho-1, Nqo-1, and Gclm genes was increased in 661W cells after exposure to RS9. Furthermore, RS9 decreased the light-induced death of 661W cells (2500 lux, 24 h), and also reduced the functional damages and the histological degeneration of the nuclei in the outer nuclear layer or the retina in the in vivo studies (8000 lux, 3 h). Heme oxygenase-1 was increased after light exposure, and Nrf2 was translocated into the nucleus after light exposure in vivo. Silencing of Ho-1 reduced the protective effects of RS9 against light-induced death of 661W cells. These findings indicate that RS9 has therapeutic potential for retinal diseases that are aggravated by light exposure. © 2017 International Society for Neurochemistry.

  2. The effect of Mastin® on expression of Nrf2 in the rat heart with subtotally nephrectomy chronic Kidney disease model

    NASA Astrophysics Data System (ADS)

    Nathania, J.; Soetikno, V.

    2017-08-01

    Chronic kidney disease (CKD) is increasingly prevalent in Indonesia and worldwide. One of the major causes of morbidity and mortality in CKD is the complication of cardiovascular disease. Mastin® is a supplement that is locally produced in Indonesia and is made from extract of mangosteen pericarp, which is reported to have antioxidative, anti-inflammatory, and antitumor properties. The present study aimed to investigate whether Mastin® could improve antioxidant responses in the rat heart during CKD by measuring the expression of nuclear factor erythroid-2-related factor (Nrf)2, a master regulator of antioxidant response elements. RNA was extracted from the heart tissue of three groups of rats: a normal group, a nephrectomy group, and a nephrectomy with Mastin® group. Two-step real-time RT-PCR was then conducted to calculate the relative expression of the Nrf2 gene. Nrf2 expression was markedly decreased in the nephrectomy group vs the normal group, but slightly increas ed in the nephrectomy with Mastin® group vs the nephrectomy group. CKD resulted in impaired activation of the Nrf2 pathway in the rat heart. Although the administration of Mastin® slightly increased Nrf2 expression, it was not enough to confer cardioprotective effects through the Nrf2 pathway.

  3. Lipoxin A4-Induced Heme Oxygenase-1 Protects Cardiomyocytes against Hypoxia/Reoxygenation Injury via p38 MAPK Activation and Nrf2/ARE Complex

    PubMed Central

    Chen, Xiao-Qing; Wu, Sheng-Hua; Zhou, Yu; Tang, Yan-Rong

    2013-01-01

    Objective To investigate whether lipoxin A4 (LXA4) increases expression of heme oxygenase-1(HO-1) in cardiomyocytes, whether LXA4-induced HO-1 protects cardiomyocytes against hypoxia/reoxygenation (H/R) injury, and what are the mechanisms involved in the LXA4-induced HO-1 induction. Methods Rat cardiomyocytes were exposed to H/R injury with or without preincubation with LXA4 or HO-1 inhibitor ZnPP-IX or various signal molecule inhibitors. Expressions of HO-1 protein and mRNA were analyzed by using Western blot and RT-PCR respectively. Activity of nuclear factor E2-related factor 2 (Nrf2) binding to the HO-1 E1 enhancer was assessed by chromatin immunoprecipitation. Nrf2 binding to the HO-1 antioxidant responsive element (ARE) were measured by using electrophoretic mobility shift assay. Results Pretreatment of the cells undergoing H/R lesion with LXA4 significantly reduced the lactate dehydrogenase and creatine kinase productions, increased the cell viability, and increased the expressions of HO-1 protein and mRNA and HO-1 promoter activity. HO-1 inhibition abolished the protective role of LXA4 on the cells undergoing H/R lesion. LXA4 increased p38 mitogen-activated protein kinase (p38 MAPK) activation, nuclear translocation of Nrf2, Nrf2 binding to the HO-1 ARE and E1 enhancer in cardiomyocytes with or without H/R exposure. Conclusion The protection role of LXA4 against H/R injury of cardiomyocytes is related to upregulation of HO-1, via activation of p38 MAPK pathway and nuclear translocation of Nrf2 and Nrf2 binding to the HO-1 ARE and E1 enhancer, but not via activation of phosphatidyinositol-3-kinase or extracellular signal-regulated kinase pathway. PMID:23826208

  4. Induction of the pi class of glutathione S-transferase by carnosic acid in rat Clone 9 cells via the p38/Nrf2 pathway.

    PubMed

    Lin, Chia-Yuan; Wu, Chi-Rei; Chang, Shu-Wei; Wang, Yu-Jung; Wu, Jia-Jiuan; Tsai, Chia-Wen

    2015-06-01

    Induction of phase II enzymes is important in cancer chemoprevention. We compared the effect of rosemary diterpenes on the expression of the pi class of glutathione S-transferase (GSTP) in rat liver Clone 9 cells and the signaling pathways involved. Culturing cells with 1, 5, 10, or 20 μM carnosic acid (CA) or carnosol (CS) for 24 h in a dose-dependent manner increased the GSTP expression. CA was more potent than CS. The RNA level and the enzyme activity of GSTP were also enhanced by CA treatment. Treatment with 10 μM CA highly induced the reporter activity of the enhancer element GPEI. Furthermore, CA markedly increased the translocation of nuclear factor erythroid-2 related factor 2 (Nrf2) from the cytosol to the nucleus after 30 to 60 min. CA the stimulated the protein induction of p38, nuclear Nrf2, and GSTP was diminished in the presence of SB203580 (a p38 inhibitor). In addition, SB203580 pretreatment or silencing of Nrf2 by siRNA suppressed the CA-induced GPEI-DNA binding activity and GSTP protein expression. Knockdown of p38 or Nrf2 by siRNA abolished the activation of p38 and Nrf2 as well as the protein induction and enzyme activity of GSTP by CA. These results suggest that CA up-regulates the expression and enzyme activity of GSTP via the p38/Nrf2/GPEI pathway.

  5. EGFR mediates astragaloside IV-induced Nrf2 activation to protect cortical neurons against in vitro ischemia/reperfusion damages

    DOE Office of Scientific and Technical Information (OSTI.GOV)

    Gu, Da-min; Lu, Pei-Hua, E-mail: lphty1_1@163.com; Zhang, Ke

    In this study, we tested the potential role of astragaloside IV (AS-IV) against oxygen and glucose deprivation/re-oxygenation (OGD/R)-induced damages in murine cortical neurons, and studied the associated signaling mechanisms. AS-IV exerted significant neuroprotective effects against OGD/R by reducing reactive oxygen species (ROS) accumulation, thereby attenuating oxidative stress and neuronal cell death. We found that AS-IV treatment in cortical neurons resulted in NF-E2-related factor 2 (Nrf2) signaling activation, evidenced by Nrf2 Ser-40 phosphorylation, and its nuclear localization, as well as transcription of antioxidant-responsive element (ARE)-regulated genes: heme oxygenase-1 (HO-1), NAD(P)H:quinone oxidoreductase 1 (NQO-1) and sulphiredoxin 1 (SRXN-1). Knockdown of Nrf2 throughmore » lentiviral shRNAs prevented AS-IV-induced ARE genes transcription, and abolished its anti-oxidant and neuroprotective activities. Further, we discovered that AS-IV stimulated heparin-binding-epidermal growth factor (HB-EGF) release to trans-activate epidermal growth factor receptor (EGFR) in cortical neurons. Blockage or silencing EGFR prevented Nrf2 activation by AS-IV, thus inhibiting AS-IV-mediated anti-oxidant and neuroprotective activities against OGD/R. In summary, AS-IV protects cortical neurons against OGD/R damages through activating of EGFR-Nrf2 signaling. - Highlights: • Pre-treatment of astragaloside IV (AS-IV) protects murine cortical neurons from OGD/R. • AS-IV activates Nrf2-ARE signaling in murine cortical neurons. • Nrf2 is required for AS-IV-mediated anti-oxidant and neuroprotective activities. • AS-IV stimulates HB-EGF release to trans-activate EGFR in murine cortical neurons. • EGFR mediates AS-IV-induced Nrf2 activation and neuroprotection against OGD/R.« less

  6. Nrf2 deficiency improves glucose tolerance in mice fed a high-fat diet

    DOE Office of Scientific and Technical Information (OSTI.GOV)

    Zhang, Yu-Kun Jennifer; Wu, Kai Connie; Liu, Jie

    Nrf2, a master regulator of intracellular redox homeostasis, is indicated to participate in fatty acid metabolism in liver. However, its role in diet-induced obesity remains controversial. In the current study, genetically engineered Nrf2-null, wild-type (WT), and Nrf2-activated, Keap1-knockdown (K1-KD) mice were fed either a control or a high-fat Western diet (HFD) for 12 weeks. The results indicate that the absence or enhancement of Nrf2 activity did not prevent diet-induced obesity, had limited effects on lipid metabolism, but affected blood glucose homeostasis. Whereas the Nrf2-null mice were resistant to HFD-induced glucose intolerance, the Nrf2-activated K1-KD mice exhibited prolonged elevation of circulatingmore » glucose during a glucose tolerance test even on the control diet. Feeding a HFD did not activate the Nrf2 signaling pathway in mouse livers. Fibroblast growth factor 21 (Fgf21) is a liver-derived anti-diabetic hormone that exerts glucose- and lipid-lowering effects. Fgf21 mRNA and protein were both elevated in livers of Nrf2-null mice, and Fgf21 protein was lower in K1-KD mice than WT mice. The inverse correlation between Nrf2 activity and hepatic expression of Fgf21 might explain the improved glucose tolerance in Nrf2-null mice. Furthermore, a more oxidative cellular environment in Nrf2-null mice could affect insulin signaling in liver. For example, mRNA of insulin-like growth factor binding protein 1, a gene repressed by insulin in hepatocytes, was markedly elevated in livers of Nrf2-null mice. In conclusion, genetic alteration of Nrf2 does not prevent diet-induced obesity in mice, but deficiency of Nrf2 improves glucose homeostasis, possibly through its effects on Fgf21 and/or insulin signaling. -- Highlights: ► Nrf2 deficiency improves glucose tolerance in mice fed a high-fat diet. ► The anti-diabetic hormone, Fgf21, is highly expressed in livers of Nrf2-null mice. ► The absence of Nrf2 increases the insulin-regulated Igfbp-1 mRNA in

  7. Alkaloids from Piper nigrum Exhibit Antiinflammatory Activity via Activating the Nrf2/HO-1 Pathway.

    PubMed

    Ngo, Quynh Mai Thi; Tran, Phuong Thao; Tran, Manh Hung; Kim, Jeong Ah; Rho, Seong Soo; Lim, Chi-Hwan; Kim, Jin-Cheol; Woo, Mi Hee; Choi, Jae Sui; Lee, Jeong-Hyung; Min, Byung Sun

    2017-04-01

    In the present study, ten alkaloids, namely chabamide (1), pellitorine (2), retrofractamide A (3), pyrroperine (4), isopiperolein B (5), piperamide C9:1 (8E) (6), 6,7-dehydrobrachyamide B (7), 4,5-dihydropiperine (8), dehydropipernonaline (9), and piperine (10), were isolated from the fruits of Piper nigrum. Among these, chabamide (1), pellitorine (2), retrofractamide A (3), isopiperolein B (5), and 6,7-dehydrobrachyamide B (7) exhibited significant inhibitory activity on lipopolysaccharide-induced nitric oxide (NO) production in RAW264.7 cells, with IC 50 values of 6.8, 14.5, 30.2, 23.7, and 38.5 μM, respectively. Furthermore, compound 1 inhibited lipopolysaccharide-induced NO production in bone marrow-derived macrophages with IC 50 value of 9.5 μM. Consistent with NO inhibition, treatment of RAW264.7 cells with chabamide (1), pellitorine (2), and 6,7-dehydrobrachyamide B (7) suppressed expression of inducible NO synthase and cyclooxygenase-2. Chabamide (1), pellitorine (2), and 6,7-dehydrobrachyamide B (7) induced heme-oxygenase-1 expression at the transcriptional level. In addition, compound 1 induced the nuclear translocation of nuclear factor-E2-related factor 2 (Nrf2) and upregulated the expression of Nrf2 target genes, NAD(P)H:quinone oxidoreductase 1 and γ-glutamyl cysteine synthetase catalytic subunit, in a concentration-dependent manner in RAW264.7 cells. These findings suggest that chabamide (1) from P. nigrum exert antiinflammatory effects via the activation of the Nrf2/heme-oxygenase-1 pathway; hence, it might be a promising candidate for the treatment of inflammatory diseases. Copyright © 2017 John Wiley & Sons, Ltd. Copyright © 2017 John Wiley & Sons, Ltd.

  8. Suppression of NRF2–ARE activity sensitizes chemotherapeutic agent-induced cytotoxicity in human acute monocytic leukemia cells

    DOE Office of Scientific and Technical Information (OSTI.GOV)

    Peng, Hui; Institute of Disease Control and Prevention, Academy of Military Medical Sciences, Beijing; Wang, Huihui

    2016-02-01

    Nuclear factor erythroid 2-related factor 2 (NRF2), a master regulator of the antioxidant response element (ARE)-dependent transcription, plays a pivotal role in chemical detoxification in normal and tumor cells. Consistent with previous findings that NRF2–ARE contributes to chemotherapeutic resistance of cancer cells, we found that stable knockdown of NRF2 by lentiviral shRNA in human acute monocytic leukemia (AML) THP-1 cells enhanced the cytotoxicity of several chemotherapeutic agents, including arsenic trioxide (As{sub 2}O{sub 3}), etoposide and doxorubicin. Using an ARE-luciferase reporter expressed in several human and mouse cells, we identified a set of compounds, including isonicotinic acid amides, isoniazid and ethionamide,more » that inhibited NRF2–ARE activity. Treatment of THP-1 cells with ethionamide, for instance, significantly reduced mRNA expression of multiple ARE-driven genes under either basal or As{sub 2}O{sub 3}-challenged conditions. As determined by cell viability and cell cycle, suppression of NRF2–ARE by ethionamide also significantly enhanced susceptibility of THP-1 and U937 cells to As{sub 2}O{sub 3}-induced cytotoxicity. In THP-1 cells, the sensitizing effect of ethionamide on As{sub 2}O{sub 3}-induced cytotoxicity was highly dependent on NRF2. To our knowledge, the present study is the first to demonstrate that ethionamide suppresses NRF2–ARE signaling and disrupts the transcriptional network of the antioxidant response in AML cells, leading to sensitization to chemotherapeutic agents. - Highlights: • Identification of novel inhibitors of ARE-dependent transcription • Suppression of NRF2–ARE sensitizes THP-1 cells to chemotherapy. • Ethionamide suppresses ARE-dependent transcriptional activity. • Ethionamide and isoniazid increase the cytotoxicity of As{sub 2}O{sub 3} in AML cells. • Sensitization of THP-1 cells to As{sub 2}O{sub 3} toxicity by ethionamide is NRF2-dependent.« less

  9. Nrf2 activator ameliorates hemorrhagic transformation in focal cerebral ischemia under warfarin anticoagulation.

    PubMed

    Imai, Takahiko; Takagi, Toshinori; Kitashoji, Akira; Yamauchi, Keita; Shimazawa, Masamitsu; Hara, Hideaki

    2016-05-01

    Oxidative stress has been reported to be a main cause of neuronal cell death in ischemia reperfusion injury (IRI). Nuclear factor-erythroid 2-related factor 2 (Nrf2) is an important factor involved in anti-oxidative responses. We previously reported that bardoxolone methyl (BARD), an Nrf2 activator, prevented damage induced by IRI. In this study, we investigated the effect of BARD on hemorrhagic transformation in the context of blood brain barrier (BBB) protection. Mice received pre-treatment with warfarin (4.0 mg/kg, p.o.). IRI was subsequently induced 18 h after the warfarin administration by transient middle cerebral artery occlusion (MCAO) for 6 h. BARD (0.06, 0.2, 0.6 or 2.0 mg/kg) or saline was injected intravenously immediately after reperfusion. The infarct volume, neurological score, intracranial hemorrhage volume, and BBB permeability were evaluated 24 h after MCAO. The survival rate and behavioral functional recovery were evaluated for 7 days following IRI. Furthermore, the effects of BARD on BBB components were investigated by western blotting and immunostaining analysis. BARD suppressed warfarin-mediated increases in the intracranial hemorrhage volume without affecting the infarct volume. BBB permeability was also suppressed by administration of BARD. Western blotting showed that BARD increased expression of BBB components such as endothelial cells, pericytes, and tight junction proteins. Furthermore, immunostaining showed that BARD induced localization of Nrf2 to endothelial cells and pericytes. BARD suppressed the exacerbation hemorrhage caused by warfarin pretreatment and ameliorated BBB disruption by protecting endothelial cells, pericytes, and tight junction protein expressions. These results indicate that Nrf2 activators may be an effective therapy against hemorrhagic transformation caused by anticoagulant drugs. Copyright © 2016 Elsevier Inc. All rights reserved.

  10. Co-regulation of nuclear respiratory factor-1 by NFκB and CREB links LPS-induced inflammation to mitochondrial biogenesis

    PubMed Central

    Suliman, Hagir B.; Sweeney, Timothy E.; Withers, Crystal M.; Piantadosi, Claude A.

    2010-01-01

    The nuclear respiratory factor-1 (NRF1) gene is activated by lipopolysaccharide (LPS), which might reflect TLR4-mediated mitigation of cellular inflammatory damage via initiation of mitochondrial biogenesis. To test this hypothesis, we examined NRF1 promoter regulation by NFκB, and identified interspecies-conserved κB-responsive promoter and intronic elements in the NRF1 locus. In mice, activation of Nrf1 and its downstream target, Tfam, by Escherichia coli was contingent on NFκB, and in LPS-treated hepatocytes, NFκB served as an NRF1 enhancer element in conjunction with NFκB promoter binding. Unexpectedly, optimal NRF1 promoter activity after LPS also required binding by the energy-state-dependent transcription factor CREB. EMSA and ChIP assays confirmed p65 and CREB binding to the NRF1 promoter and p65 binding to intron 1. Functionality for both transcription factors was validated by gene-knockdown studies. LPS regulation of NRF1 led to mtDNA-encoded gene expression and expansion of mtDNA copy number. In cells expressing plasmid constructs containing the NRF-1 promoter and GFP, LPS-dependent reporter activity was abolished by cis-acting κB-element mutations, and nuclear accumulation of NFκB and CREB demonstrated dependence on mitochondrial H2O2. These findings indicate that TLR4-dependent NFκB and CREB activation co-regulate the NRF1 promoter with NFκB intronic enhancement and redox-regulated nuclear translocation, leading to downstream target-gene expression, and identify NRF-1 as an early-phase component of the host antibacterial defenses. PMID:20587593

  11. Dietary moderately oxidized oil activates the Nrf2 signaling pathway in the liver of pigs.

    PubMed

    Varady, Juliane; Gessner, Denise K; Most, Erika; Eder, Klaus; Ringseis, Robert

    2012-02-24

    Previous studies have shown that administration of oxidized oils increases gene expression and activities of various enzymes involved in xenobiotic metabolism and stress response in the liver of rats and guinea pigs. As these genes are controlled by nuclear factor erythroid-derived 2-like 2 (Nrf2), we investigated the hypothesis that feeding of oxidized fats causes an activation of that transcription factor in the liver which in turn activates the expression of antioxidant, cytoprotective and detoxifying genes. Twenty four crossbred pigs were allocated to two groups of 12 pigs each and fed nutritionally adequate diets with either fresh rapeseed oil (fresh fat group) or oxidized rapeseed oil prepared by heating at a temperature of 175°C for 72 h (oxidized fat group). After 29 days of feeding, pigs of the oxidized fat group had a markedly increased nuclear concentration of the transcription factor Nrf2 and a higher activity of cellular superoxide dismutase and T4-UDP glucuronosyltransferase in liver than the fresh fat group (P < 0.05). In addition, transcript levels of antioxidant and phase II genes in liver, like superoxide dismutase 1, heme oxygenase 1, glutathione peroxidase 1, thioredoxin reductase 1, microsomal glutathione-S-transferase 1, UDP glucuronosyltransferase 1A1 and NAD(P)H:quinone oxidoreductase 1 in the liver were higher in the oxidized fat group than in the fresh fat group (P < 0.05). Moreover, pigs of the oxidized fat group had an increased hepatic nuclear concentration of the transcription factor NF-κB which is also an important transcription factor mediating cellular stress response. The present study shows for the first time that administration of an oxidized fat activates the Nrf2 in the liver of pigs which likely reflects an adaptive mechanism to prevent cellular oxidative damage. Activation of the NF-κB pathway might also contribute to this effect of oxidized fat.

  12. Reserpine Inhibit the JB6 P+ Cell Transformation Through Epigenetic Reactivation of Nrf2-Mediated Anti-oxidative Stress Pathway.

    PubMed

    Hong, Bo; Su, Zhengyuan; Zhang, Chengyue; Yang, Yuqing; Guo, Yue; Li, Wenjing; Kong, Ah-Ng Tony

    2016-05-01

    Nuclear factor erythroid-2 related factor 2 (Nrf2) is a crucial transcription factor that regulates the expression of defensive antioxidants and detoxification enzymes in cells. In a previous study, we showed that expression of the Nrf2 gene is regulated by an epigenetic modification. Rauvolfia verticillata, a traditional Chinese herbal medicine widely used in China, possesses anticancer and antioxidant effects. In this study, we investigated how Nrf2 is epigenetically regulated by reserpine, the main active component in R. verticillata, in mouse skin epidermal JB6 P+ cells. Reserpine induced ARE (antioxidant response element)-luciferase activity in HepG2-C8 cells. Accordingly, in JB6 P+ cells, it upregulated the mRNA and protein levels of Nrf2 and its downstream target genes heme oxygenase-1 (HO-1) and quinone oxidoreductase 1 (NQO1), while it only increased the protein level of UDP-glucuronosyltransferase 1A1 (UGT1A1). Furthermore, reserpine decreased the TPA (12-O-tetradecanoylphorbol-13-acetate)-induced colony formation of JB6 cells in a dose-dependent manner. DNA sequencing and methylated DNA immunoprecipitation further demonstrated the demethylation effect of reserpine on the first 15 CpGs of the Nrf2 promoter in JB6 P+ cells. Reserpine also reduced the mRNA and protein expression of DNMT1 (DNA methyltransferase 1), DNMT3a (DNA methyltransferases 3a), and DNMT3b (DNA methyltransferases 3b). Moreover, reserpine induced Nrf2 expression via an epigenetic pathway in skin epidermal JB6 P+ cells, enhancing the protective antioxidant activity and decreasing TPA-induced cell transformation. These results suggest that reserpine exhibits a cancer preventive effect by reactivating Nrf2 and inducing the expression of target genes involved in cellular protection, potentially providing new insight into the chemoprevention of skin cancer using reserpine.

  13. PCB 126 toxicity is modulated by cross-talk between caveolae and Nrf2 signaling

    DOE Office of Scientific and Technical Information (OSTI.GOV)

    Petriello, Michael C.; University of Kentucky Superfund Research Center, Lexington, KY 40536; Han, Sung Gu

    2014-06-01

    Environmental toxicants such as polychlorinated biphenyls (PCBs) have been implicated in the promotion of multiple inflammatory disorders including cardiovascular disease, but information regarding mechanisms of toxicity and cross-talk between relevant cell signaling pathways is lacking. To examine the hypothesis that cross-talk between membrane domains called caveolae and nuclear factor (erythroid-derived 2)-like 2 (Nrf2) pathways alters PCB-induced inflammation, caveolin-1 was silenced in vascular endothelial cells, resulting in a decreased PCB-induced inflammatory response. Cav-1 silencing (siRNA treatment) also increased levels of Nrf2-ARE transcriptional binding, resulting in higher mRNA levels of the antioxidant genes glutathione s-transferase and NADPH dehydrogenase quinone-1 in both vehiclemore » and PCB-treated systems. Along with this upregulated antioxidant response, Cav-1 siRNA treated cells exhibited decreased mRNA levels of the Nrf2 inhibitory protein Keap1 in both vehicle and PCB-treated samples. Silencing Cav-1 also decreased protein levels of Nrf2 inhibitory proteins Keap1 and Fyn kinase, especially in PCB-treated cells. Further, endothelial cells from wildtype and Cav-1 −/− mice were isolated and treated with PCB to better elucidate the role of functional caveolae in PCB-induced endothelial inflammation. Cav-1 −/− endothelial cells were protected from PCB-induced cellular dysfunction as evidenced by decreased vascular cell adhesion molecule (VCAM-1) protein induction. Compared to wildtype cells, Cav-1 −/− endothelial cells also allowed for a more effective antioxidant response, as observed by higher levels of the antioxidant genes. These data demonstrate novel cross-talk mechanisms between Cav-1 and Nrf2 and implicate the reduction of Cav-1 as a protective mechanism for PCB-induced cellular dysfunction and inflammation. - Highlights: • Reduction of caveolin-1 protein protects against polychlorinated biphenyl toxicity.

  14. NRF1 Is an ER Membrane Sensor that Is Central to Cholesterol Homeostasis.

    PubMed

    Widenmaier, Scott B; Snyder, Nicole A; Nguyen, Truc B; Arduini, Alessandro; Lee, Grace Y; Arruda, Ana Paula; Saksi, Jani; Bartelt, Alexander; Hotamisligil, Gökhan S

    2017-11-16

    Cholesterol is a critical nutrient requiring tight constraint in the endoplasmic reticulum (ER) due to its uniquely challenging biophysical properties. While the mechanisms by which the ER defends against cholesterol insufficiency are well described, it remains unclear how the ER senses and effectively defends against cholesterol excess. Here, we identify the ER-bound transcription factor nuclear factor erythroid 2 related factor-1, Nrf1/Nfe2L1, as a critical mediator of this process. We show that Nrf1 directly binds to and specifically senses cholesterol in the ER through a defined domain and that cholesterol regulates Nrf1 turnover, processing, localization, and activity. In Nrf1 deficiency, in vivo cholesterol challenges induce massive hepatic cholesterol accumulation and damage, which is rescued by replacing Nrf1 exogenously. This Nrf1-mediated mechanism involves the suppression of CD36-driven inflammatory signaling and derepression of liver X receptor activity. These findings reveal Nrf1 as a guardian of cholesterol homeostasis and a core component of adaptive responses to excess cellular cholesterol. Copyright © 2017. Published by Elsevier Inc.

  15. Neuroprotection against 6-OHDA toxicity in PC12 cells and mice through the Nrf2 pathway by a sesquiterpenoid from Tussilago farfara.

    PubMed

    Lee, Joohee; Song, Kwangho; Huh, Eugene; Oh, Myung Sook; Kim, Yeong Shik

    2018-06-01

    Oxidative stress plays a key role in neurodegenerative diseases such as Alzheimer's and Parkinson's diseases. Therefore, the nuclear factor-E2-related factor 2 (Nrf2), a key regulator of the antioxidative response, is considered to be important as a therapeutic target for neurodegenerative diseases. We investigated the underlying mechanism of Nrf2-mediated neuroprotective effects against oxidative stress in the PC12 cell line by 7β-(3-ethyl-cis-crotonoyloxy)-1α-(2-methylbutyryloxy)-3,14-dehydro-Z-notonipetranone (ECN), one of the sesquiterpenoids in Farfarae Flos. Pretreatment of PC12 cells with ECN had a protective effect against hydrogen peroxide (H 2 O 2 )- or 6-hydroxydopamine (6-OHDA)-induced cytotoxicity. ECN upregulated the ARE-luciferase activity and induced the mRNA expression of Nrf2 and antioxidant enzyme heme oxygenase-1 (HO-1). Knockdown of Nrf2 by small, interfering RNA (siRNA) abrogated the upregulation of HO-1, indicating that ECN had induced HO-1 via the Nrf2 pathway. Pretreatment with the thiol reducing agents, N-acetylcysteine (NAC) or dithiothreitol (DTT), attenuated Nrf2 activation and HO-1 expression. However, the non-thiol reducing antioxidant, Trolox, failed to inhibit HO-1 induction by ECN. These results suggest that ECN may directly interact with Kelch-like ECH-associated protein 1 (Keap1) and modify critical cysteine thiols present in the proteins responsible for Nrf2-mediated upregulation of HO-1. In a 6-OHDA-induced mouse model of PD, administration of ECN ameliorated motor impairments and dopaminergic neuronal damage. Taken together, ECN exerts neuroprotective effects by activating the Nrf2/HO-1 signaling pathway in both PC12 cells and mice. Thus, ECN, as an Nrf2 activator, could be an attractive therapeutic candidate for the neuroprotection or treatment of neurodegenerative diseases. Copyright © 2018 The Authors. Published by Elsevier B.V. All rights reserved.

  16. Estrogen increases Nrf2 activity through activation of the PI3K pathway in MCF-7 breast cancer cells

    DOE Office of Scientific and Technical Information (OSTI.GOV)

    Wu, Juanjuan, E-mail: jwu32@emory.edu; Williams, Devin; Walter, Grant A.

    The actions of the transcription factor Nuclear factor erythroid 2-related factor (Nrf2) in breast cancer have been shown to include both pro-oncogenic and anti-oncogenic activities which is influenced, at least in part, by the hormonal environment. However, direct regulation of Nrf2 by steroid hormones (estrogen and progesterone) has received only scant attention. Nrf2 is known to be regulated by its cytosolic binding protein, Kelch-like ECH-associated protein 1 (Keap1), and by a Keap1-independent mechanism involving a series of phosphorylation steps mediated by phosphatidylinositol 3-kinase (PI3K) and glycogen synthase kinase 3 beta (GSK3β). Here, we report that estrogen (E2) increases Nrf2 activitymore » in MCF7 breast cancer cells through activation of the PI3K/GSK3β pathway. Utilizing antioxidant response element (ARE)-containing luciferase reporter constructs as read-outs for Nrf2 activity, our data indicated that E2 increased ARE activity >14-fold and enhanced the action of the Nrf2 activators, tertiary butylhydroquinone (tBHQ) and sulforaphane (Sul) 4 to 9 fold compared with cells treated with tBHQ or Sul as single agents. This activity was shown to be an estrogen receptor-mediated phenomenon and was antagonized by progesterone. In addition to its action on the reporter constructs, mRNA and protein levels of heme oxygenase 1, an endogenous target gene of Nrf2, was markedly upregulated by E2 both alone and in combination with tBHQ. Importantly, E2-induced Nrf2 activation was completely suppressed by the PI3K inhibitors LY294002 and Wortmannin while the GSK3β inhibitor CT99021 upregulated Nrf2 activity. Confirmation that E2 was, at least partly, acting through the PI3K/GSK3β pathway was indicated by our finding that E2 increased the phosphorylation status of both GSK3β and Akt, a well-characterized downstream target of PI3K. Together, these results demonstrate a novel mechanism by which E2 can regulate Nrf2 activity in estrogen receptor-positive breast

  17. Characterization of Nrf2 activation and heme oxygenase-1 expression in NIH3T3 cells exposed to aqueous extracts of cigarette smoke.

    PubMed

    Knörr-Wittmann, Constanze; Hengstermann, Arnd; Gebel, Stephan; Alam, Jawed; Müller, Thomas

    2005-12-01

    Cigarette smoke (CS) is a complex chemical mixture estimated to be composed of up to 5000 different chemicals, many of which are prooxidant. Here we show that, at least in vitro, the cellular response designed to combat oxidative stress resulting from CS exposure is primarily controlled by the transcription factor Nrf2, a principal inducer of antioxidant and phase II-related genes. The prominent role of Nrf2 in the cellular response to CS is substantiated by the following observations: In NIH3T3 cells exposed to aqueous extracts of CS (i) Nrf2 is strongly stabilized and becomes detectable in nuclear extracts. (ii) Nuclear localization of Nrf2 coincides with increased DNA binding of a putative Nrf2/MafK heterodimer to its cognate cis-regulatory site, i.e., the antioxidant-responsive element (ARE). (iii) Studies on the regulatory elements of the oxidative stress-inducible gene heme oxygenase-1 (hmox1) using various hmox1 promoter/luciferase reporter constructs revealed that the strong CS-dependent expression of this gene is primarily governed by the distal enhancers 1 ("E1") and 2 ("E2"), which both contain three canonical ARE-like stress-responsive elements (StREs). Notably, depletion of Nrf2 levels caused by RNA interference significantly compromised CS-induced hmox1 promoter activation, based on the distinct Nrf2 sensitivity exhibited by E1 and E2. Finally, (iv) siRNA-dependent knock-down of Nrf2 completely abrogated CS-induced expression of phase II-related genes. Taken together, these results confirm the outstanding role of Nrf2 both in sensing (oxidant) stress and in orchestrating an efficient transcriptional response aimed at resolving the stressing conditions.

  18. NRF2-regulated metabolic gene signature as a prognostic biomarker in non-small cell lung cancer

    PubMed Central

    Namani, Akhileshwar; Cui, Qin Qin; Wu, Yihe; Wang, Hongyan; Wang, Xiu Jun; Tang, Xiuwen

    2017-01-01

    Mutations in Kelch-like ECH-associated protein 1 (KEAP1) cause the aberrant activation of nuclear factor erythroid-derived 2-like 2 (NRF2), which leads to oncogenesis and drug resistance in lung cancer cells. Our study was designed to identify the genes involved in lung cancer progression targeted by NRF2. A series of microarray experiments in normal and cancer cells, as well as in animal models, have revealed regulatory genes downstream of NRF2 that are involved in wide variety of pathways. Specifically, we carried out individual and combinatorial microarray analysis of KEAP1 overexpression and NRF2 siRNA-knockdown in a KEAP1 mutant-A549 non-small cell lung cancer (NSCLC) cell line. As a result, we identified a list of genes which were mainly involved in metabolic functions in NSCLC by using functional annotation analysis. In addition, we carried out in silico analysis to characterize the antioxidant responsive element sequences in the promoter regions of known and putative NRF2-regulated metabolic genes. We further identified an NRF2-regulated metabolic gene signature (NRMGS) by correlating the microarray data with lung adenocarcinoma RNA-Seq gene expression data from The Cancer Genome Atlas followed by qRT-PCR validation, and finally showed that higher expression of the signature conferred a poor prognosis in 8 independent NSCLC cohorts. Our findings provide novel prognostic biomarkers for NSCLC. PMID:29050246

  19. The role of Her2-Nrf2 axis in induction of oxaliplatin resistance in colon cancer cells.

    PubMed

    Pirpour Tazehkand, Abbas; Akbarzadeh, Maryam; Velaie, Kobra; Sadeghi, Mohammad Reza; Samadi, Nasser

    2018-04-20

    Nuclear factor erythroid 2-related factor 2 (Nrf2) plays a pivotal role in promoting chemoresistance by regulation of antioxidants and detoxification enzymes. Her2 is a member of tyrosine kinase receptor family with a key function in resistance of cancer cells to chemotherapeutics. The aim of this study was to investigate the possible cross talk between Nrf2 and Her2 mediated signaling pathways in development of oxaliplatin resistance in colon cancer cells. We first generated oxaliplatin-resistant LS174T and SW480 colon cancer cells with different Her2 expression levels by employing IC50 concentrations followed by a resting period. We evaluated the viability and apoptosis of the cells by MTT and flow cytometry assays, respectively. Nrf2 and Her2 gene expression levels were examined by qRT-PCR. The morphology analysis and combination index calculation were performed using the ImagJ and CompuSyn softwares, respectively. Development of resistant cells revealed a marked increase in half maximal inhibitory concentration (IC50) value from 3.95 ± 0.92 μM to 29.27 ± 3.13 μM in SW480 cells and 377 ± 46 nM to 9.59 ± 0.76 μM in LS174T cells with a significant change in morphology of the cells from elongated to small round shape (p < 0.05). Her2 expression level was increased in both types of resistant cells, but the Nrf2 expression was increased in LS174T resistant (LS174T/Res) cells and decreased in SW480/Res cells which were consistent with the level of resistance in these cells (25 fold increase in IC50 value in LS174T/Res cells versus 7 fold increase in this value in SW480/Res cells). Inhibition of either Nrf2 or Her2 alone and in combination caused a significant increase in oxaliplatin-induced cytotoxicity and apoptosis with maximum effects in SW480/Res cells with low Her2 and Nrf2 expression levels. Altogether, our results suggest that inhibition of Nrf2 signaling in colon cancer patients with Her2 overexpression can be considered as

  20. The effects of chromium picolinate and chromium histidinate administration on NF-κB and Nrf2/HO-1 pathway in the brain of diabetic rats.

    PubMed

    Sahin, Kazim; Tuzcu, Mehmet; Orhan, Cemal; Gencoglu, Hasan; Ulas, Mustafa; Atalay, Mustafa; Sahin, Nurhan; Hayirli, Armagan; Komorowski, James R

    2012-12-01

    The objective of this experiment was to investigate the effects of supplemental chromium picolinate (CrPic) and chromium histidinate (CrHis) on nuclear factor-kappa B (NF-κB p65) and nuclear factor (erythroid-derived 2)-like 2 (Nrf2) signaling pathway in diabetic rat brain. Nondiabetic (n = 45) and diabetic (n = 45) male Wistar rats were either not supplemented or supplemented with CrPic or CrHis via drinking water to consume 8 μg elemental chromium (Cr) per day for 12 weeks. Diabetes was induced by streptozotocin injection (40 mg/kg i.p., for 2 weeks) and maintained by high-fat feeding (40 %). Diabetes was associated with increases in cerebral NF-κB and 4-hydroxynonenal (4-HNE) protein adducts and decreased in cerebral nuclear factor of kappa light polypeptide gene enhancer in B cells inhibitor, alpha (IκBα) and Nrf2 levels. Both Cr chelates were effective to decrease levels of NF-κB and 4-HNE protein adducts and to increase levels of IκBα and Nrf2 in the brain of diabetic rats. However, responses of these increases and decreases were more notable when Cr was supplemented as CrHis than as CrPic. In conclusion, Cr may play a protective role in cerebral antioxidant defense system in diabetic subjects via the Nrf2 pathway by reducing inflammation through NF-κB p65 inhibition. Histidinate form of Cr was superior to picolinate form of Cr in reducing NF-κB expression and increasing Nrf2 expression in the brain of diabetic rats.

  1. Ferulic acid (FA) abrogates γ-radiation induced oxidative stress and DNA damage by up-regulating nuclear translocation of Nrf2 and activation of NHEJ pathway.

    PubMed

    Das, Ujjal; Manna, Krishnendu; Khan, Amitava; Sinha, Mahuya; Biswas, Sushobhan; Sengupta, Aaveri; Chakraborty, Anindita; Dey, Sanjit

    2017-01-01

    The present study was aimed to evaluate the radioprotective effect of ferulic acid (FA), a naturally occurring plant flavonoid in terms of DNA damage and damage related alterations of repair pathways by gamma radiation. FA was administered at a dose of 50 mg/kg body weight for five consecutive days prior to exposing the swiss albino mice to a single dose of 10 Gy gamma radiation. Ionising radiation induces oxidative damage manifested by decreased expression of Cu, Zn-SOD (SOD stands for super oxide dismutase), Mn-SOD and catalase. Gamma radiation promulgated reactive oxygen species (ROS) mediated DNA damage and modified repair pathways. ROS enhanced nuclear translocation of p53, activated ATM (ataxia telangiectasia-mutated protein), increased expression of GADD45a (growth arrest and DNA-damage-inducible protein) gene and inactivated Non homologous end joining (NHEJ) repair pathway. The comet formation in irradiated mice peripheral blood mononuclear cells (PBMC) reiterated the DNA damage in IR exposed groups. FA pretreatment significantly prevented the comet formation and regulated the nuclear translocation of p53, inhibited ATM activation and expression of GADD45a gene. FA promoted the nuclear translocation of nuclear factor (erythroid-derived 2)-like 2 (Nrf2) and activated NHEJ repair pathway to overcome ROS mediated oxidative stress and DNA damage. Therefore, the current study stated that FA can challenge the oxidative stress by (i) inducing nuclear translocation of Nrf2, (ii) scavenging ROS, and (iii) activating NHEJ DNA repair process.

  2. Curcumin ameliorates dopaminergic neuronal oxidative damage via activation of the Akt/Nrf2 pathway.

    PubMed

    Cui, Qunli; Li, Xin; Zhu, Hongcan

    2016-02-01

    Parkinson's disease (PD) is an age-related complex neurodegenerative disease that affects ≤ 80% of dopaminergic neurons in the substantia nigra pars compacta (SNpc). It has previously been suggested that mitochondrial dysfunction, oxidative stress and oxidative damage underlie the pathogenesis of PD. Curcumin, which is a major active polyphenol component extracted from the rhizomes of Curcuma longa (Zingiberaceae), has been reported to exert neuroprotective effects on an experimental model of PD. The present study conducted a series of in vivo experiments, in order to investigate the effects of curcumin on behavioral deficits, oxidative damage and related mechanisms. The results demonstrated that curcumin was able to significantly alleviate motor dysfunction and increase suppressed tyrosine hydroxylase (TH) activity in the SNpc of rotenone (ROT)-injured rats. Biochemical measurements indicated that rats pretreated with curcumin exhibited increased glutathione (GSH) levels, and reduced reactive oxygen species activity and malondialdehyde content. Mechanistic studies demonstrated that curcumin significantly restored the expression levels of heme oxygenase-1 and quinone oxidoreductase 1, thus ameliorating ROT-induced damage in vivo, via the phosphorylation of Akt and nuclear factor erythroid 2-related factor 2 (Nrf2). Further studies indicated that the Akt/Nrf2 signaling pathway was associated with the protective role of curcumin in ROT-treated rats. Inhibiting the Akt/Nrf2 pathway using a lentiviral vector containing Nrf2-specific short hairpin RNA, or the phosphoinositide 3-kinase inhibitor LY294002, markedly reduced the expression levels of TH and GSH, ultimately attenuating the neuroprotective effects of curcumin against oxidative damage. These results indicated that curcumin was able to significantly ameliorate ROT-induced dopaminergic neuronal oxidative damage in the SNpc of rats via activation of the Akt/Nrf2 signaling pathway.

  3. Cross Talk in HEK293 Cells Between Nrf2, HIF, and NF-κB Activities upon Challenges with Redox Therapeutics Characterized with Single-Cell Resolution.

    PubMed

    Johansson, Katarina; Cebula, Marcus; Rengby, Olle; Dreij, Kristian; Carlström, Karl E; Sigmundsson, Kristmundur; Piehl, Fredrik; Arnér, Elias S J

    2017-02-20

    Many transcription factors with importance in health and disease are redox regulated. However, how their activities may be intertwined in responses to redox-perturbing stimuli is poorly understood. To enable in-depth characterization of this aspect, we here developed a methodology for simultaneous determination of nuclear factor E2-related factor 2 (Nrf2), hypoxia-inducible factor (HIF), and nuclear factor kappa-light-chain-enhancer of activated B cell (NF-κB) activation at single-cell resolution, using a new tool named pTRAF (plasmid for transcription factor reporter activation based upon fluorescence). The pTRAF allowed determination of Nrf2, HIF, and NF-κB activities in a high-resolution and high-throughput manner, and we here assessed how redox therapeutics affected the activities of these transcription factors in human embryonic kidney cells (HEK293). Cross talk was detected between the three signaling pathways upon some types of redox therapeutics, also by using inducers typically considered specific for Nrf2, such as sulforaphane or auranofin, hypoxia for HIF activation, or tumor necrosis factor alpha (TNFα) for NF-κB stimulation. Doxorubicin, at low nontoxic doses, potentiated TNFα-induced activation of NF-κB and HIF, without effects in stand-alone treatment. Stochastic activation patterns in cell cultures were also considerable upon challenges with several redox stimuli. A novel strategy was here used to study simultaneous activation of Nrf2, HIF, and NF-κB in single cells. The method can also be adapted for studies of other transcription factors. The pTRAF provides new opportunities for in-depth studies of transcription factor activities. In this study, we found that upon challenges of cells with several redox-perturbing conditions, Nrf2, HIF, and NF-κB are uniquely responsive to separate stimuli, but can also display marked cross talk to each other within single cells. Antioxid. Redox Signal. 26, 229-246.

  4. Sulforaphane attenuates di-N-butylphthalate-induced reproductive damage in pubertal mice: Involvement of the Nrf2-antioxidant system.

    PubMed

    Jiang, Xu-Ping; Tang, Jing-Yuan; Xu, Zhen; Han, Peng; Qin, Zhi-Qiang; Yang, Cheng-di; Wang, Shang-Qian; Tang, Min; Wang, Wei; Qin, Chao; Xu, Yang; Shen, Bai-Xin; Zhou, Wei-Min; Zhang, Wei

    2017-07-01

    di-N-butylphthalate (DBP) is a ubiquitous environmental pollutant used for plastic coating and in the cosmetics industry. It has toxic effects on body health, especially the male reproductive system. Here, we investigated the effects of DBP on the male reproductive system of pubertal mice and explored the protective role of sulforaphane (SFN). The results showed that DBP significantly reduced the anogenital distance, testicular weight, sperm count and motility, and plasma and testicular testosterone levels and significantly increased the oxidative stress, sperm abnormalities, and testicular cell apoptosis. SFN supplementation ameliorated these effects. After DBP stimulation, the transcription factor nuclear factor erythroid-related factor 2 (Nrf2) was adaptively increased together with its target genes, such as HO-1 and NQO1. Upregulation of Nrf2 by SFN reduced the DBP-mediated intracellular oxidative toxicity and also increased testosterone secretion and spermatogenesis, which were decreased by DBP. These findings indicate that SFN can attenuate DBP-induced reproductive damage in pubertal mice via Nrf2-associated pathways. © 2017 Wiley Periodicals, Inc.

  5. Carvedilol, a third-generation β-blocker prevents oxidative stress-induced neuronal death and activates Nrf2/ARE pathway in HT22 cells

    DOE Office of Scientific and Technical Information (OSTI.GOV)

    Ouyang, Ying; Chen, Ziwei; Tan, Min

    Highlights: •Carvedilol significantly prevented oxidative stress-induced cell death. •Carvedilol significantly decreased the production of ROS. •Carvedilol activated Nrf2/ARE pathway. •Carvedilol increased the protein levels of HO-1 and NQO-1. -- Abstract: Carvedilol, a nonselective β-adrenoreceptor blocker with pleiotropic activities has been shown to exert neuroprotective effect due to its antioxidant property. However, the neuroprotective mechanism of carvedilol is still not fully uncovered. Nuclear factor E2-related factor 2 (Nrf2)/antioxidant response element (ARE) pathway is an important cellular stress response pathway involved in neuroprotection. Here we investigated the effect of carvedilol on oxidative stress-induced cell death (glutamate 2 mM and H{sub 2}O{sub 2}more » 600 μM) and the activity of Nrf2/ARE pathway in HT22 hippocampal cells. Carvedilol significantly increased cell viability and decreased ROS in HT22 cells exposed to glutamate or H{sub 2}O{sub 2}. Furthermore, carvedilol activated the Nrf2/ARE pathway in a concentration-dependent manner, and increased the protein levels of heme oxygenase-1(HO-1) and NAD(P)H quinone oxidoreductase-1(NQO-1), two downstream factors of the Nrf2/ARE pathway. Collectively, our results indicate that carvedilol protects neuronal cell against glutamate- and H{sub 2}O{sub 2}-induced neurotoxicity possibly through activating the Nrf2/ARE signaling pathway.« less

  6. Advanced glycation end products influence oral cancer cell survival via Bcl-xl and Nrf-2 regulation in vitro.

    PubMed

    Ko, Shun-Yao; Ko, Hshin-An; Shieh, Tzong-Ming; Chi, Tzong-Cherng; Chen, Hong-I; Chen, Yi-Ting; Yu, Ya-Hui; Yang, Shu-Han; Chang, Shu-Shing

    2017-05-01

    An irreversible non-enzymatic reaction between carbohydrates and proteins results in the formation of advanced glycation end products (AGEs). AGEs have been demonstrated to be a risk factor of complications in patients with diabetes mellitus (DM). Previous studies have suggested that patients with DM exhibit a higher rate of metastasis of oral cancer and a lower cancer-associated survival rate. The receptor for AGEs (RAGE) has been associated with angiogenesis and an increase in cancer malignancy. Previous studies have suggested that AGE-RAGE regulates cell migration via extracellular signal-regulated kinase (ERK) phosphorylation. Nuclear factor-erythroid 2-related factor 2 (Nrf-2) is associated with the regulation of tumor protein p53 (p53) and the apoptotic response of oral cancer cells. AGEs are associated with oral cancer; however, the mechanism underlying this association remains to be elucidated. The present study hypothesized that AGEs regulate Nrf-2 and downstream pathways through ERK phosphorylation. The results of the current study demonstrated that AGEs inhibit the expression of Nrf-2, p53 and Bcl-2 associated × apoptosis regulator, and increase the expression of apoptosis regulator Bcl-x protein. The effect of AGEs was inhibited through the use of the PD98059. The present study demonstrated that AGEs regulate the downstream pathways Nrf-2 and Bcl-xl via ERK phosphorylation. It is suggested that AGEs regulate the survival of oral cancer cells via Nrf-2 and Bcl-xl through p53 regulation, which explains the poor prognosis of patients with DM who have oral cancer.

  7. Fisetin Imparts Neuroprotection in Experimental Diabetic Neuropathy by Modulating Nrf2 and NF-κB Pathways.

    PubMed

    Sandireddy, Reddemma; Yerra, Veera Ganesh; Komirishetti, Prashanth; Areti, Aparna; Kumar, Ashutosh

    2016-08-01

    The current study is aimed to assess the therapeutic potential of fisetin, a phytoflavonoid in streptozotocin (STZ)-induced experimental diabetic neuropathy (DN) in rats. Fisetin was administered (5 and 10 mg/kg) for 2 weeks (7th and 8th week) post STZ administration. Thermal and mechanical hyperalgesia were assessed by measuring tactile sensitivity to thermal and mechanical stimuli, respectively. Motor nerve conduction velocity (MNCV) was determined using power lab system and sciatic nerve blood flow (NBF) was determined using laser Doppler system. Nerve sections were processed for TUNEL assay and NF-κB, COX-2 immunohistochemical staining. Sciatic nerve homogenate was used for biochemical and Western blotting analysis. MNCV and sciatic NBF deficits associated with DN were ameliorated in fisetin administered rats. Fisetin treatment reduced the interleukin-6 and tumour necrosis factor-alpha in sciatic nerves of diabetic rats (p < 0.001). Protein expression studies have identified that the therapeutic benefit of fisetin might be through regulation of redox sensitive transcription factors such as nuclear erythroid 2-related factor 2 (Nrf2) and nuclear factor kappa B (NF-κB). Our study provides an evidence for the therapeutic potential of fisetin in DN through simultaneous targeting of NF-κB and Nrf2.

  8. Deficiency in Nrf2 transcription factor decreases adipose tissue mass and hepatic lipid accumulation in leptin-deficient mice.

    PubMed

    Xu, Jialin; Donepudi, Ajay C; More, Vijay R; Kulkarni, Supriya R; Li, Liya; Guo, Liangran; Yan, Bingfang; Chatterjee, Tapan; Weintraub, Neal; Slitt, Angela L

    2015-02-01

    To evaluate whether Nrf2 deficiency impacts insulin resistance and lipid accumulation in liver and white adipose tissue. Lep(ob/ob) mice (OB) with targeted Nrf2 deletion (OB-Nrf2KO) were generated. Pathogenesis of obesity and type 2 diabetes was measured in C57BL/6J, Nrf2KO, OB, and OB-Nrf2KO mice. Hepatic lipid content, lipid clearance, and very low-density lipoprotein (VLDL) secretion were determined between OB and OB-Nrf2KO mice. OB-Nrf2KO mice exhibited decreased white adipose tissue mass and decreased adipogenic and lipogenic gene expression compared with OB mice. Nrf2 deficiency prolonged hyperglycemia in response to glucose challenge, which was paralleled by reduced insulin-stimulated Akt phosphorylation. In OB mice, Nrf2 deficiency decreased hepatic lipid accumulation, decreased peroxisome proliferator-activated receptor γ expression and nicotinamide adenine dinucleotide phosphate (NADPH) content, and enhanced VLDL secretion. However, this observation was opposite in lean mice. Additionally, OB-Nrf2KO mice exhibited increased plasma triglyceride content, decreased HDL-cholesterol content, and enhanced apolipoprotein B expression, suggesting Nrf2 deficiency caused dyslipidemia in these mice. Nrf2 deficiency in Lep(ob/ob) mice reduced white adipose tissue mass and prevented hepatic lipid accumulation but induced insulin resistance and dyslipidemia. This study indicates a dual role of Nrf2 during metabolic dysregulation-increasing lipid accumulation in liver and white adipose tissue but preventing lipid accumulation in obese mice. © 2014 The Obesity Society.

  9. Neuroprotection by Curcumin in Ischemic Brain Injury Involves the Akt/Nrf2 Pathway

    PubMed Central

    Wu, Jingxian; Li, Qiong; Wang, Xiaoyan; Yu, Shanshan; Li, Lan; Wu, Xuemei; Chen, Yanlin; Zhao, Jing; Zhao, Yong

    2013-01-01

    Oxidative damage plays a critical role in many diseases of the central nervous system. This study was conducted to determine the molecular mechanisms involved in the putative anti-oxidative effects of curcumin against experimental stroke. Oxygen and glucose deprivation/reoxygenation (OGD/R) was used to mimic ischemic insult in primary cultured cortical neurons. A rapid increase in the intracellular expression of NAD(P)H: quinone oxidoreductase1 (NQO1) induced by OGD was counteracted by curcumin post-treatment, which paralleled attenuated cell injury. The reduction of phosphorylation Akt induced by OGD was restored by curcumin. Consequently, NQO1 expression and the binding activity of nuclear factor-erythroid 2-related factor 2 (Nrf2) to antioxidant response element (ARE) were increased. LY294002 blocked the increase in phospho-Akt evoked by curcumin and abolished the associated protective effect. Adult male Sprague-Dawley rats were subjected to transient middle cerebral artery occlusion for 60 minutes. Curcumin administration significantly reduced infarct size. Curcumin also markedly reduced oxidative stress levels in middle cerebral artery occlusion (MCAO) rats; hence, these effects were all suppressed by LY294002. Taken together, these findings provide evidence that curcumin protects neurons against ischemic injury, and this neuroprotective effect involves the Akt/Nrf2 pathway. In addition, Nrf2 is involved in the neuroprotective effects of curcumin against oxidative damage. PMID:23555802

  10. CNC-bZIP protein Nrf1-dependent regulation of glucose-stimulated insulin secretion.

    PubMed

    Zheng, Hongzhi; Fu, Jingqi; Xue, Peng; Zhao, Rui; Dong, Jian; Liu, Dianxin; Yamamoto, Masayuki; Tong, Qingchun; Teng, Weiping; Qu, Weidong; Zhang, Qiang; Andersen, Melvin E; Pi, Jingbo

    2015-04-01

    The inability of pancreatic β-cells to secrete sufficient insulin in response to glucose stimulation is a major contributing factor to the development of type 2 diabetes (T2D). We investigated both the in vitro and in vivo effects of deficiency of nuclear factor-erythroid 2-related factor 1 (Nrf1) in β-cells on β-cell function and glucose homeostasis. Silencing of Nrf1 in β-cells leads to a pre-T2D phenotype with disrupted glucose metabolism and impaired insulin secretion. Specifically, MIN6 β-cells with stable knockdown of Nrf1 (Nrf1-KD) and isolated islets from β-cell-specific Nrf1-knockout [Nrf1(b)-KO] mice displayed impaired glucose responsiveness, including elevated basal insulin release and decreased glucose-stimulated insulin secretion (GSIS). Nrf1(b)-KO mice exhibited severe fasting hyperinsulinemia, reduced GSIS, and glucose intolerance. Silencing of Nrf1 in MIN6 cells resulted in oxidative stress and altered glucose metabolism, with increases in both glucose uptake and aerobic glycolysis, which is associated with the elevated basal insulin release and reduced glucose responsiveness. The elevated glycolysis and reduced glucose responsiveness due to Nrf1 silencing likely result from altered expression of glucose metabolic enzymes, with induction of high-affinity hexokinase 1 and suppression of low-affinity glucokinase. Our study demonstrated a novel role of Nrf1 in regulating glucose metabolism and insulin secretion in β-cells and characterized Nrf1 as a key transcription factor that regulates the coupling of glycolysis and mitochondrial metabolism and GSIS. Nrf1 plays critical roles in regulating glucose metabolism, mitochondrial function, and insulin secretion, suggesting that Nrf1 may be a novel target to improve the function of insulin-secreting β-cells.

  11. A novel Nrf2 activator from microbial transformation inhibits radiation-induced dermatitis in mice

    PubMed Central

    Nakagami, Yasuhiro; Masuda, Kayoko

    2016-01-01

    Nuclear factor erythroid 2-related factor 2 (Nrf2) is a transcriptional factor that regulates many antioxidants, and we have recently succeeded in obtaining a novel Nrf2 activator, RS9, from microbial transformation. RS9 is categorized as a triterpenoid, and well-known triterpenoids such as RTA 402 (bardoxolone methyl) and RTA 408 have been tested in clinical trials. RTA 408 lotion is currently being tested in patients at risk for radiation dermatitis. This prompted us to study the profiles of RS9 in the skin. All the above triterpenoids increased the level of an Nrf2-targeted gene, NADPH:quinone oxidoreductase-1, in normal human epidermal keratinocytes. Among them, the activity of RS9 was prominent; furthermore, the cellular toxicity was less compared with RTA compounds. BALB/c mice were irradiated with 30 Gy/day on Day 0, and compounds were topically applied on the back once daily from Day 1 to Day 30. Dermatitis scores peaked on Day 18, with a score of 2.6 in vehicle-treated mice, and topical applications of 0.1% RTA 402, RTA 408 and RS9 reduced the scores to 1.8, 2.0 and 1.4, respectively. Moreover, the percentage of animals with scores ≥2 was analyzed, and 0.1% RS9 suppressed the percentage from 100% to 47%. These results imply that RS9 has potential efficacy for treating radiation dermatitis. PMID:27242339

  12. Lycopene inhibits NF-κB activation and adhesion molecule expression through Nrf2-mediated heme oxygenase-1 in endothelial cells.

    PubMed

    Yang, Po-Min; Chen, Huang-Zhi; Huang, Yu-Ting; Hsieh, Chia-Wen; Wung, Being-Sun

    2017-06-01

    The endothelial expression of cell adhesion molecules plays a leading role in atherosclerosis. Lycopene, a carotenoid with 11 conjugated double bonds, has been shown to have anti-inflammatory properties. In the present study, we demonstrate a putative mechanism for the anti-inflammatory effects of lycopene. We demonstrate that lycopene inhibits the adhesion of tumor necrosis factor α (TNFα)-stimulated monocytes to endothelial cells and suppresses the expression of intercellular cell adhesion molecule-1 (ICAM-1) at the transcriptional level. Moreover, lycopene was found to exert its inhibitory effects by blocking the degradation of the inhibitory protein, IκBα, following 6 h of pre-treatment. In TNFα-stimulated endothelial cells, nuclear factor-κB (NF-κB) nuclear translocation and transcriptional activity were abolished by up to 12 h of lycopene pre-treatment. We also found that lycopene increased the intracellular glutathione (GSH) level and glutamate-cysteine ligase expression. Subsequently, lycopene induced nuclear factor-erythroid 2 related factor 2 (Nrf2) activation, leading to the increased expression of downstream of heme oxygenase-1 (HO-1). The use of siRNA targeting HO-1 blocked the inhibitory effects of lycopene on IκB degradation and ICAM-1 expression. The inhibitory effects of lycopene thus appear to be mediated through its induction of Nrf2-mediated HO-1 expression. Therefore, the findings of the present study indicate that lycopene suppresses the activation of TNFα-induced signaling pathways through the upregulation of Nrf2-mediated HO-1 expression.

  13. The chalcone compound isosalipurposide (ISPP) exerts a cytoprotective effect against oxidative injury via Nrf2 activation

    DOE Office of Scientific and Technical Information (OSTI.GOV)

    Han, Jae Yun; Cho, Seung Sik; Yang, Ji Hye

    2015-08-15

    The chalcone compound isosalipurposide (ISPP) has been successfully isolated from the native Korean plant species Corylopsis coreana Uyeki (Korean winter hazel). However, the therapeutic efficacy of ISPP remains poorly understood. This study investigated whether ISPP has the capacity to activate NF-E2-related factor (Nrf2)-antioxidant response element (ARE) signaling and induce its target gene expression, and to determined the protective role of ISPP against oxidative injury of hepatocytes. In HepG2 cells, nuclear translocation of Nrf2 is augmented by ISPP treatment. Consistently, ISPP increased ARE reporter gene activity and the protein levels of glutamate cysteine ligase (GCL) and hemeoxygenase (HO-1), resulting in increasedmore » intracellular glutathione levels. Cells pretreated with ISPP were rescued from tert-butylhydroperoxide-induced reactive oxygen species (ROS) production and glutathione depletion and consequently, apoptotic cell death. Moreover, ISPP ameliorated the mitochondrial dysfunction and apoptosis induced by rotenone which is an inhibitor of complex 1 of the mitochondrial respiratory chain. The specific role of Nrf2 activation by ISPP was demonstrated using an ARE-deletion mutant plasmid and Nrf2-knockout cells. Finally, we observed that extracellular signal-regulated kinase (ERK) and AMP-activated protein kinase (AMPK), but not protein kinase C (PKC)-δ or other mitogen-activated protein kinases (MAPKs), are involved in the activation of Nrf2 by ISPP. Taken together, our results demonstrate that ISPP has a cytoprotective effect against oxidative damage mediated through Nrf2 activation and induction of its target gene expression in hepatocytes. - Highlights: • We investigated the effect of ISPP on Nrf2 activation. • ISPP increased Nrf2 activity and its target gene expression. • ISPP inhibited the mitochondrial dysfunction and ROS production. • Nrf2 activation by ISPP is dependent on ERK1/2 and AMPK phosphorylation. • ISPP may be a

  14. Hydrogen sulphide induces HIF-1α and Nrf2 in THP-1 macrophages.

    PubMed

    Lohninger, Lilian; Tomasova, Lenka; Praschberger, Monika; Hintersteininger, Michael; Erker, Thomas; Gmeiner, Bernhard M K; Laggner, Hilde

    2015-05-01

    The transcription factor HIF-1α regulates the adaptive response of cells to hypoxia and oxidative stress. In addition, an important regulatory role for HIF-1α in immune reactions and inflammation is suggested. The present study attempts to investigate the effect of the gaseous signalling molecule hydrogen sulphide (H2S) on HIF-1α in THP-1 macrophages using the slow H2S releasing donor GYY4137. We found that H2S induced HIF-1α protein accumulation in THP-1 macrophages in a concentration-dependent manner. Western blot analysis of cell fractions showed that HIF-1α protein translocates into the nucleus and leads to an increase of its target protein glucose transporter-1 (GLUT-1). Activation of nuclear factor-κB (NF-κB), as well as secretion of the pro-inflammatory cytokines tumor necrosis factor-α (TNF-α) and interleukin-6 (IL-6), were reduced in the presence of H2S. These findings indicate that HIF-1α accumulation due to H2S was not triggered by the NF-κB pathway. The antioxidant pathway Nrf2/HO-1 (nuclear factor erythroid 2-related factor 2/heme oxygenase-1) was activated by H2S. Inhibition of the p38 mitogen-activated protein kinase (MAPK) reversed H2S mediated effects, suggesting that the p38 MAPK pathway may be involved in H2S induced HIF-1α/Nrf2 signalling pathways. Copyright © 2015 Elsevier B.V. and Société Française de Biochimie et Biologie Moléculaire (SFBBM). All rights reserved.

  15. Absence of Nrf2 or Its Selective Overexpression in Neurons and Muscle Does Not Affect Survival in ALS-Linked Mutant hSOD1 Mouse Models

    PubMed Central

    Vargas, Marcelo R.; Burton, Neal C.; Gan, Li; Johnson, Delinda A.; Schäfer, Matthias; Werner, Sabine; Johnson, Jeffrey A.

    2013-01-01

    The nuclear factor erythroid 2-related factor 2 (Nrf2) governs the expression of antioxidant and phase II detoxifying enzymes. Nrf2 activation can prevent or reduce cellular damage associated with several types of injury in many different tissues and organs. Dominant mutations in Cu/Zn-superoxide dismutase (SOD1) cause familial forms of amyotrophic lateral sclerosis (ALS), a fatal disorder characterized by the progressive loss of motor neurons and subsequent muscular atrophy. We have previously shown that Nrf2 activation in astrocytes delays neurodegeneration in ALS mouse models. To further investigate the role of Nrf2 in ALS we determined the effect of absence of Nrf2 or its restricted overexpression in neurons or type II skeletal muscle fibers on symptoms onset and survival in mutant hSOD1 expressing mice. We did not observe any detrimental effect associated with the lack of Nrf2 in two different mutant hSOD1 animal models of ALS. However, restricted Nrf2 overexpression in neurons or type II skeletal muscle fibers delayed disease onset but failed to extend survival in hSOD1G93A mice. These results highlight the concept that not only the pharmacological target but also the cell type targeted may be relevant when considering a Nrf2-mediated therapeutic approach for ALS. PMID:23418589

  16. Absence of Nrf2 or its selective overexpression in neurons and muscle does not affect survival in ALS-linked mutant hSOD1 mouse models.

    PubMed

    Vargas, Marcelo R; Burton, Neal C; Kutzke, Jennifer; Gan, Li; Johnson, Delinda A; Schäfer, Matthias; Werner, Sabine; Johnson, Jeffrey A

    2013-01-01

    The nuclear factor erythroid 2-related factor 2 (Nrf2) governs the expression of antioxidant and phase II detoxifying enzymes. Nrf2 activation can prevent or reduce cellular damage associated with several types of injury in many different tissues and organs. Dominant mutations in Cu/Zn-superoxide dismutase (SOD1) cause familial forms of amyotrophic lateral sclerosis (ALS), a fatal disorder characterized by the progressive loss of motor neurons and subsequent muscular atrophy. We have previously shown that Nrf2 activation in astrocytes delays neurodegeneration in ALS mouse models. To further investigate the role of Nrf2 in ALS we determined the effect of absence of Nrf2 or its restricted overexpression in neurons or type II skeletal muscle fibers on symptoms onset and survival in mutant hSOD1 expressing mice. We did not observe any detrimental effect associated with the lack of Nrf2 in two different mutant hSOD1 animal models of ALS. However, restricted Nrf2 overexpression in neurons or type II skeletal muscle fibers delayed disease onset but failed to extend survival in hSOD1(G93A) mice. These results highlight the concept that not only the pharmacological target but also the cell type targeted may be relevant when considering a Nrf2-mediated therapeutic approach for ALS.

  17. The Protective Effect of Glycyrrhetinic Acid on Carbon Tetrachloride-Induced Chronic Liver Fibrosis in Mice via Upregulation of Nrf2

    PubMed Central

    Chen, Shaoru; Zou, Liyi; Li, Li; Wu, Tie

    2013-01-01

    This study was designed to investigate the potentially protective effects of glycyrrhetinic acid (GA) and the role of transcription factor nuclear factor-erythroid 2(NF-E2)-related factor 2 (Nrf2) signaling in the regulation of Carbon Tetrachloride (CCl4)-induced chronic liver fibrosis in mice. The potentially protective effects of GA on CCl4-induced chronic liver fibrosis in mice were depicted histologically and biochemically. Firstly, histopathological changes including regenerative nodules, inflammatory cell infiltration and fibrosis were induced by CCl4.Then, CCl4 administration caused a marked increase in the levels of serum aminotransferases (GOT, GPT), serum monoamine oxidase (MAO) and lipid peroxidation (MDA) as well as MAO in the mice liver homogenates. Also, decreased nuclear Nrf2 expression, mRNA levels of its target genes such as superoxide dismutase 3 (SOD3), catalase (CAT), glutathione peroxidase 2 (GPX2), and activity of cellular antioxidant enzymes were found after CCl4 exposure. All of these phenotypes were markedly reversed by the treatment of the mice with GA. In addition, GA exhibited the antioxidant effects in vitro by on FeCl2-ascorbate induced lipid peroxidation in mouse liver homogenates, and on DPPH scavenging activity. Taken together, these results suggested that GA can protect the liver from oxidative stress in mice, presumably through activating the nuclear translocation of Nrf2, enhancing the expression of its target genes and increasing the activity of the antioxidant enzymes. Therefore, GA may be an effective hepatoprotective agent and viable candidate for treating liver fibrosis and other oxidative stress-related diseases. PMID:23341968

  18. Impact of epigallocatechin‑3‑gallate on expression of nuclear factor erythroid 2‑related factor 2 and γ‑glutamyl cysteine synthetase genes in oxidative stress‑induced mouse renal tubular epithelial cells.

    PubMed

    Du, Xuanyi; Yu, Jinfeng; Sun, Xiaohan; Qu, Shaochuan; Zhang, Haitao; Hu, Mengying; Yang, Shufen; Zhou, Ping

    2018-06-01

    The aim of the present study was to investigate the antioxidant response mechanism of epigallocatechin‑3‑gallate (EGCG) in H2O2‑induced mouse renal tubular epithelial cells (MRTECs). The cultured MRTECs were divided into normal, H2O2 (control) and EGCG treatment groups. The MTT assay was used to assess cell viability, and reverse transcription‑quantitative polymerase chain reaction (RT‑qPCR), immunocytochemical and western blot analyses were performed to detect the expression of nuclear factor erythroid 2‑related factor 2 (Nrf2) and γ‑glutamyl cysteine synthetase (γ‑GCS). EGCG was able to mitigate H2O2‑mediated cell damage. The RT‑qPCR results demonstrated that EGCG was able to upregulate the gene expression of Nrf2 and γ‑GCS in MRTECs in a dose‑dependent manner. The immunocytochemistry and western blot analyses demonstrated that EGCG was able to increase the protein expression of Nrf2 and γ‑GCS in MRTECs in a dose‑dependent manner. Oxidative stress may lead to a decrease in the viability of MRTECs, while EGCG was able to promote the expression of Nrf2 and γ‑GCS in MRTECs, thereby improving the antioxidant capacity of the cells and promoting the repair of oxidative stress injury.

  19. Genetic polymorphism of the Nrf2 promoter region is associated with vitiligo risk in Han Chinese populations.

    PubMed

    Song, Pu; Li, Kai; Liu, Ling; Wang, Xiaowen; Jian, Zhe; Zhang, Weigang; Wang, Gang; Li, Chunying; Gao, Tianwen

    2016-10-01

    The nuclear factor erythroid-derived two-like 2-antioxidant response element (Nrf2-ARE) pathway and its downstream antioxidant enzyme heme oxygenase-1 (HMOX1 or HO-1) play essential roles in H2 O2 -induced oxidative damage in human melanocytes. However, the link between Nrf2 promoter polymorphisms and susceptibility to oxidative stress-related diseases such as vitiligo is unknown. This study evaluated the association of the Nrf2 and HO-1 genes polymorphisms with vitiligo susceptibility. In this case-control study of 1136 Han Chinese vitiligo patients and 1200 controls, Nrf2 (rs35652124 and rs6721961) and HO-1 (rs2071746) genes were genotyped by PCR-restriction fragment length polymorphism analysis. Overall, a significantly decreased risk of vitiligo was found to be associated with Nrf2 rs35652124 CC and combined (CT+CC) genotypes [odds ratio (OR) 0.64, 95% confidence interval (CI) 0.50-0.83 and OR, 0.84, 95% CI 0.71-0.99, respectively], as well as among subgroups: female, onset age ≤20 and never smoker. We subsequently found that Nrf2 rs35652124 C allele had higher transcriptional activity in the luciferase reporter assay compared with Nrf2 rs35652124 T allele. Furthermore, we investigated serum HO-1 activity was associated with the rs35652124 CT+CC genotype and lower in patients than in controls (P = 0.024). Logistic regression analysis showed a dose-response relationship between lower vitiligo risk and increased HO-1 activity in rs35652124 CT+CC genotype carriers (Ptrend < 0.05). These findings indicate that the C allele of rs35652124 located in the promoter region of Nrf2 gene is associated with protective effect on vitiligo in a Han Chinese population. © 2016 The Authors. Journal of Cellular and Molecular Medicine published by John Wiley & Sons Ltd and Foundation for Cellular and Molecular Medicine.

  20. Sulforaphane Protects Pancreatic Acinar Cell Injury by Modulating Nrf2-Mediated Oxidative Stress and NLRP3 Inflammatory Pathway

    PubMed Central

    Dong, Zhaojun; Shang, Haixiao; Chen, Yong Q.; Pan, Li-Long

    2016-01-01

    Acute pancreatitis (AP) is characterized by early activation of intra-acinar proteases followed by acinar cell death and inflammation. Cellular oxidative stress is a key mechanism underlying these pathological events. Sulforaphane (SFN) is a natural organosulfur antioxidant with undescribed effects on AP. Here we investigated modulatory effects of SFN on cellular oxidation and inflammation in AP. AP was induced by cerulean hyperstimulation in BALB/c mice. Treatment group received a single dose of 5 mg/kg SFN for 3 consecutive days before AP. We found that SFN administration attenuated pancreatic injury as evidenced by serum amylase, pancreatic edema, and myeloperoxidase, as well as by histological examination. SFN administration reverted AP-associated dysregulation of oxidative stress markers including pancreatic malondialdehyde and redox enzymes superoxide dismutase (SOD) and glutathione peroxidase (GPx). In acinar cells, SFN treatment upregulated nuclear factor erythroid 2-related factor 2 (Nrf2) expression and Nrf2-regulated redox genes including quinoneoxidoreductase-1, heme oxidase-1, SOD1, and GPx1. In addition, SFN selectively suppressed cerulein-induced activation of the nucleotide-binding domain leucine-rich repeat containing family, pyrin domain-containing 3 (NLRP3) inflammasome, in parallel with reduced nuclear factor- (NF-) κB activation and modulated NF-κB-responsive cytokine expression. Together, our data suggested that SFN modulates Nrf2-mediated oxidative stress and NLRP3/NF-κB inflammatory pathways in acinar cells, thereby protecting against AP. PMID:27847555

  1. Sulforaphane Protects Pancreatic Acinar Cell Injury by Modulating Nrf2-Mediated Oxidative Stress and NLRP3 Inflammatory Pathway.

    PubMed

    Dong, Zhaojun; Shang, Haixiao; Chen, Yong Q; Pan, Li-Long; Bhatia, Madhav; Sun, Jia

    2016-01-01

    Acute pancreatitis (AP) is characterized by early activation of intra-acinar proteases followed by acinar cell death and inflammation. Cellular oxidative stress is a key mechanism underlying these pathological events. Sulforaphane (SFN) is a natural organosulfur antioxidant with undescribed effects on AP. Here we investigated modulatory effects of SFN on cellular oxidation and inflammation in AP. AP was induced by cerulean hyperstimulation in BALB/c mice. Treatment group received a single dose of 5 mg/kg SFN for 3 consecutive days before AP. We found that SFN administration attenuated pancreatic injury as evidenced by serum amylase, pancreatic edema, and myeloperoxidase, as well as by histological examination. SFN administration reverted AP-associated dysregulation of oxidative stress markers including pancreatic malondialdehyde and redox enzymes superoxide dismutase (SOD) and glutathione peroxidase (GPx). In acinar cells, SFN treatment upregulated nuclear factor erythroid 2-related factor 2 (Nrf2) expression and Nrf2-regulated redox genes including quinoneoxidoreductase-1, heme oxidase-1, SOD1, and GPx1. In addition, SFN selectively suppressed cerulein-induced activation of the nucleotide-binding domain leucine-rich repeat containing family, pyrin domain-containing 3 (NLRP3) inflammasome, in parallel with reduced nuclear factor- (NF-) κ B activation and modulated NF- κ B-responsive cytokine expression. Together, our data suggested that SFN modulates Nrf2-mediated oxidative stress and NLRP3/NF- κ B inflammatory pathways in acinar cells, thereby protecting against AP.

  2. Sulforaphane Inhibits Lipopolysaccharide-Induced Inflammation, Cytotoxicity, Oxidative Stress, and miR-155 Expression and Switches to Mox Phenotype through Activating Extracellular Signal-Regulated Kinase 1/2-Nuclear Factor Erythroid 2-Related Factor 2/Antioxidant Response Element Pathway in Murine Microglial Cells.

    PubMed

    Eren, Erden; Tufekci, Kemal Ugur; Isci, Kamer Burak; Tastan, Bora; Genc, Kursad; Genc, Sermin

    2018-01-01

    Sulforaphane (SFN) is a natural product with cytoprotective, anti-inflammatory, and antioxidant effects. In this study, we evaluated the mechanisms of its effects on lipopolysaccharide (LPS)-induced cell death, inflammation, oxidative stress, and polarization in murine microglia. We found that SFN protects N9 microglial cells upon LPS-induced cell death and suppresses LPS-induced levels of secreted pro-inflammatory cytokines, tumor necrosis factor-alpha, interleukin-1 beta, and interleukin-6. SFN is also a potent inducer of redox sensitive transcription factor, nuclear factor erythroid 2-related factor 2 (Nrf2), which is responsible for the transcription of antioxidant, cytoprotective, and anti-inflammatory genes. SFN induced translocation of Nrf2 to the nucleus via extracellular signal-regulated kinase 1/2 (ERK1/2) pathway activation. siRNA-mediated knockdown study showed that the effects of SFN on LPS-induced reactive oxygen species, reactive nitrogen species, and pro-inflammatory cytokine production and cell death are partly Nrf2 dependent. Mox phenotype is a novel microglial phenotype that has roles in oxidative stress responses. Our results suggested that SFN induced the Mox phenotype in murine microglia through Nrf2 pathway. SFN also alleviated LPS-induced expression of inflammatory microRNA, miR-155. Finally, SFN inhibits microglia-mediated neurotoxicity as demonstrated by conditioned medium and co-culture experiments. In conclusion, SFN exerts protective effects on microglia and modulates the microglial activation state.

  3. Cardiac Aging - Benefits of Exercise, Nrf2 Activation and Antioxidant Signaling.

    PubMed

    Narasimhan, Madhusudhanan; Rajasekaran, Namakkal-Soorappan

    2017-01-01

    Cardiovascular dysfunction and heart failure associated with aging not only impairs the cardiac function but also the quality of life eventually decreasing the life expectancy of the elderly. Notably, cardiac tissue can prematurely age under certain conditions such as genetic mutation, persistent redox stress and overload, aberrant molecular signaling, DNA damage, telomere attrition, and other pathological insults. While cardiovascular-related morbidity and mortality is on the rise and remains a global health threat, there has been only little to moderate improvements in its medical management. This is due to the fact that the lifestyle changes to molecular mechanisms underlying age-related myocardial structure and functional remodeling are multifactorial and intricately operate at different levels. Along these lines, the intrinsic redox mechanisms and oxidative stress (OS) are widely studied in the myocardium. The accumulation of reactive oxygen species (ROS) with age and the resultant oxidative damage has been shown to increase the susceptibility of the myocardium to multiple complications such as atherosclerosis, hypertension, ischemic heart disease, cardiac myopathy, and heart failure. There has been growing interest in trying to enhance the mechanisms that neutralize the ROS and curtailing OS as a possible anti-aging intervention and as a treatment for age-related disorders. Natural defense system to fight against OS involves a master transcription factor named nuclear erythroid-2-p45-related factor-2 (Nrf2) that regulates several antioxidant genes. Compelling evidence exists on the Nrf2 gain of function through pharmacological interventions in counteracting the oxidative damage and affords cytoprotection in several organs including but not limited to lung, liver, kidney, brain, etc. Nevertheless, thus far, only a few studies have described the potential role of Nrf2 and its non-pharmacological induction in cardiac aging. This chapter explores the effects of

  4. t-BHQ Provides Protection against Lead Neurotoxicity via Nrf2/HO-1 Pathway

    PubMed Central

    Ye, Fang; Li, Xiaoyi; Li, Lili; Yuan, Jing; Chen, Jun

    2016-01-01

    The neurotoxicity of lead has been well established, and oxidative stress is strongly associated with lead-induced neurotoxicity. Nrf2 is important for protection against oxidative stress in many disease models. We applied t-BHQ, which is an Nrf2 activator, to investigate the possible role of Nrf2 in the protection against lead neurotoxicity. t-BHQ significantly attenuated the oxidative stress in developmental rats by decreasing MDA level, as well as by increasing SOD activity and GSH content, in the hippocampus and frontal cortex. Furthermore, neuronal apoptosis was detected by Nissl staining, and Bax expression was inhibited in the t-BHQ-treated group. Results showed that t-BHQ suppressed ROS production and caspase 3/7 activity but increased intracellular GSH content, in SH-SY5Y cells under lead exposure. Moreover, in vivo and in vitro, t-BHQ enhanced the nuclear translocation of Nrf2 and binding to ARE areas but did not induce Nrf2 transcription. These phenomena were confirmed using RT-PCR, EMSA, Western blot, and immunofluorescence analyses. Subsequent upregulation of the expression of HO-1, NQO1, and GCLC was observed. However, knockdown of Nrf2 or HO-1 adversely affected the protective effects of t-BHQ against lead toxicity in SH-SY5Y cells. Thus, t-BHQ can protect against lead neurotoxicity, depending on the Nrf2/HO-1 pathway. PMID:26798413

  5. Prediction of Binding Energy of Keap1 Interaction Motifs in the Nrf2 Antioxidant Pathway and Design of Potential High-Affinity Peptides.

    PubMed

    Karttunen, Mikko; Choy, Wing-Yiu; Cino, Elio A

    2018-06-07

    Nuclear factor erythroid 2-related factor 2 (Nrf2) is a transcription factor and principal regulator of the antioxidant pathway. The Kelch domain of Kelch-like ECH-associated protein 1 (Keap1) binds to motifs in the N-terminal region of Nrf2, promoting its degradation. There is interest in developing ligands that can compete with Nrf2 for binding to Kelch, thereby activating its transcriptional activities and increasing antioxidant levels. Using experimental Δ G bind values of Kelch-binding motifs determined previously, a revised hydrophobicity-based model was developed for estimating Δ G bind from amino acid sequence and applied to rank potential uncharacterized Kelch-binding motifs identified from interaction databases and BLAST searches. Model predictions and molecular dynamics (MD) simulations suggested that full-length MAD2A binds Kelch more favorably than a high-affinity 20-mer Nrf2 E78P peptide, but that the motif in isolation is not a particularly strong binder. Endeavoring to develop shorter peptides for activating Nrf2, new designs were created based on the E78P peptide, some of which showed considerable propensity to form binding-competent structures in MD, and were predicted to interact with Kelch more favorably than the E78P peptide. The peptides could be promising new ligands for enhancing the oxidative stress response.

  6. Prevention by sulforaphane of diabetic cardiomyopathy is associated with up-regulation of Nrf2 expression and transcription activation.

    PubMed

    Bai, Yang; Cui, Wenpeng; Xin, Ying; Miao, Xiao; Barati, Michelle T; Zhang, Chi; Chen, Qiang; Tan, Yi; Cui, Taixing; Zheng, Yang; Cai, Lu

    2013-04-01

    This study was to investigate whether sulforaphane (SFN) can prevent diabetic cardiomyopathy. Type 1 diabetes was induced in FVB mice by multiple intraperitoneal injections with low-dose streptozotocin. Hyperglycemic and age-matched control mice were treated with or without SFN at 0.5mg/kg daily in five days of each week for 3 months and then kept until 6 months. At 3 and 6 months of diabetes, blood pressure and cardiac function were assessed. Cardiac fibrosis, inflammation, and oxidative damage were assessed by Western blot, real-time qPCR, and histopathological examination. SFN significantly prevented diabetes-induced high blood pressure and cardiac dysfunction at both 3 and 6 months, and also prevented diabetes-induced cardiac hypertrophy (increased the ratio of heart weight to tibia length and the expression of atrial natriuretic peptide mRNA and protein) and fibrosis (increased the accumulation of collagen and expression of connective tissue growth factor and tissue growth factor-β). SFN also almost completely prevented diabetes-induced cardiac oxidative damage (increased accumulation of 3-nitrotyrosine and 4-hydroxynonenal) and inflammation (increased tumor necrotic factor-α and plasminogen activator inhibitor 1 expression). SFN up-regulated NFE2-related factor 2 (Nrf2) expression and transcription activity that was reflected by increased Nrf2 nuclear accumulation and phosphorylation as well as the mRNA and protein expression of Nrf2 downstream antioxidants. Furthermore, in cultured H9c2 cardiac cells silencing Nrf2 gene with its siRNA abolished the SFN's prevention of high glucose-induced fibrotic response. These results suggest that diabetes-induced cardiomyopathy can be prevented by SFN, which was associated with the up-regulated Nrf2 expression and transcription function. Copyright © 2013 Elsevier Ltd. All rights reserved.

  7. Activation of Nrf2 in keratinocytes causes chloracne (MADISH)-like skin disease in mice

    PubMed Central

    Schäfer, Matthias; Willrodt, Ann-Helen; Kurinna, Svitlana; Link, Andrea S; Farwanah, Hany; Geusau, Alexandra; Gruber, Florian; Sorg, Olivier; Huebner, Aaron J; Roop, Dennis R; Sandhoff, Konrad; Saurat, Jean-Hilaire; Tschachler, Erwin; Schneider, Marlon R; Langbein, Lutz; Bloch, Wilhelm; Beer, Hans-Dietmar; Werner, Sabine

    2014-01-01

    The transcription factor Nrf2 is a key regulator of the cellular stress response, and pharmacological Nrf2 activation is a promising strategy for skin protection and cancer prevention. We show here that prolonged Nrf2 activation in keratinocytes causes sebaceous gland enlargement and seborrhea in mice due to upregulation of the growth factor epigen, which we identified as a novel Nrf2 target. This was accompanied by thickening and hyperkeratosis of hair follicle infundibula. These abnormalities caused dilatation of infundibula, hair loss, and cyst development upon aging. Upregulation of epigen, secretory leukocyte peptidase inhibitor (Slpi), and small proline-rich protein 2d (Sprr2d) in hair follicles was identified as the likely cause of infundibular acanthosis, hyperkeratosis, and cyst formation. These alterations were highly reminiscent to the phenotype of chloracne/“metabolizing acquired dioxin-induced skin hamartomas” (MADISH) patients. Indeed, SLPI, SPRR2, and epigen were strongly expressed in cysts of MADISH patients and upregulated by dioxin in human keratinocytes in an NRF2-dependent manner. These results identify novel Nrf2 activities in the pilosebaceous unit and point to a role of NRF2 in MADISH pathogenesis. PMID:24503019

  8. Maresin 1 Ameliorates Lung Ischemia/Reperfusion Injury by Suppressing Oxidative Stress via Activation of the Nrf-2-Mediated HO-1 Signaling Pathway

    PubMed Central

    Wu, You; Zhao, Feng

    2017-01-01

    Lung ischemia/reperfusion (I/R) injury occurs in various clinical conditions and heavily damaged lung function. Oxidative stress reaction and antioxidant enzymes play a pivotal role in the etiopathogenesis of lung I/R injury. In the current study, we investigated the impact of Maresin 1 on lung I/R injury and explored the possible mechanism involved in this process. MaR 1 ameliorated I/R-induced lung injury score, wet/dry weight ratio, myeloperoxidase, tumor necrosis factor, bronchoalveolar lavage fluid (BALF) leukocyte count, BALF neutrophil ratio, and pulmonary permeability index levels in lung tissue. MaR 1 significantly reduced ROS, methane dicarboxylic aldehyde, and 15-F2t-isoprostane generation and restored antioxidative enzyme (superoxide dismutase, glutathione peroxidase, and catalase) activities. Administration of MaR 1 improved the expression of nuclear Nrf-2 and cytosolic HO-1 in I/R-treated lung tissue. Furthermore, we also found that the protective effects of MaR 1 on lung tissue injury and oxidative stress were reversed by HO-1 activity inhibitor, Znpp-IX. Nrf-2 transcription factor inhibitor, brusatol, significantly decreased MaR 1-induced nuclear Nrf-2 and cytosolic HO-1 expression. In conclusion, these results indicate that MaR 1 protects against lung I/R injury through suppressing oxidative stress. The mechanism is partially explained by activation of the Nrf-2-mediated HO-1 signaling pathway. PMID:28751936

  9. Targeting Nrf2 Signaling Improves Bacterial Clearance by Alveolar Macrophages in Patients with COPD and in a Mouse Model

    PubMed Central

    Harvey, Christopher J.; Thimmulappa, Rajesh K.; Sethi, Sanjay; Kong, Xiaoni; Yarmus, Lonny; Brown, Robert H.; David, Feller-Kopman; Wise, Robert; Biswal, Shyam

    2016-01-01

    Patients with chronic obstructive pulmonary disease (COPD) have innate immune dysfunction in the lung largely due to defective macrophage phagocytosis. This deficiency results in periodic bacterial infections that cause acute exacerbations of COPD, a major source of morbidity and mortality. Recent studies indicate that a decrease in Nrf2 (nuclear erythroid–related factor 2) signaling in patients with COPD may hamper their ability to defend against oxidative stress, although the role of Nrf2 in COPD exacerbations has not been determined. Here, we test whether activation of Nrf2 by the phytochemical sulforaphane restores phagocytosis of clinical isolates of nontypeable Haemophilus influenza (NTHI) and Pseudomonas aeruginosa (PA) by alveolar macrophages from patients with COPD. Sulforaphane treatment restored bacteria recognition and phagocytosis in alveolar macrophages from COPD patients. Furthermore, sulforaphane treatment enhanced pulmonary bacterial clearance by alveolar macrophages and reduced inflammation in wild-typemice but not in Nrf2-deficientmice exposed to cigarette smoke for 6 months. Gene expression and promoter analysis revealed that Nrf2 increased phagocytic ability of macrophages by direct transcriptional up-regulation of the scavenger receptor MARCO. Disruption of Nrf2 or MARCO abrogated sulforaphane-mediated bacterial phagocytosis by COPD alveolar macrophages. Our findings demonstrate the importance of Nrf2 and its downstream target MARCO in improving antibacterial defenses and provide a rationale for targeting this pathway, via pharmacological agents such as sulforaphane, to prevent exacerbations of COPD caused by bacterial infection. PMID:21490276

  10. 4-Methoxychalcone Enhances Cisplatin-Induced Oxidative Stress and Cytotoxicity by Inhibiting the Nrf2/ARE-Mediated Defense Mechanism in A549 Lung Cancer Cells

    PubMed Central

    Lim, Juhee; Lee, Sung Ho; Cho, Sera; Lee, Ik-Soo; Kang, Bok Yun; Choi, Hyun Jin

    2013-01-01

    Nuclear factor erythroid 2-related factor 2 (Nrf2) is a key transcriptional regulator for the protection of cells against oxidative and xenobiotic stresses. Recent studies have demonstrated that high constitutive expression of Nrf2 is observed in many types of cancer cells showing resistance to anti-cancer drugs, suggesting that the suppression of overexpressed Nrf2 could be an attractive therapeutic strategy to overcome cancer drug resistance. In the present study, we aimed to find small molecule compounds that enhance the sensitivity of tumor cells to cisplatin induced cytotoxicity by suppressing Nrf2-mediated defense mechanism. A549 lung cancer cells were shown to be more resistant to the anti-cancer drug cisplatin than HEK293 cells, with higher Nrf2 signaling activity; constitutively high amounts of Nrf2-downstream target proteins were observed in A549 cells. Among the three chalcone derivatives 4-methoxy-chalcone (4-MC), hesperidin methylchalcone, and neohesperidin dihydrochalcone, 4-MC was found to suppress transcriptional activity of Nrf2 in A549 cells but to activate it in HEK293 cells. 4-MC was also shown to down-regulate expression of Nrf2 and the downstream phase II detoxifying enzyme NQO1 in A549 cells. The PI3K/Akt pathway was found to be involved in the 4-MC-induced inhibition of Nrf2/ARE activity in A549 cells. This inhibition of Nrf2 signaling results in the accelerated generation of reactive oxygen species and exacerbation of cytotoxicity in cisplatin-treated A549 cells. Taken together, these results suggest that the small molecule compound 4-MC could be used to enhance the sensitivity of tumor cells to the therapeutic effect of cisplatin through the regulation of Nrf2/ARE signaling. PMID:24046186

  11. 4-methoxychalcone enhances cisplatin-induced oxidative stress and cytotoxicity by inhibiting the Nrf2/ARE-mediated defense mechanism in A549 lung cancer cells.

    PubMed

    Lim, Juhee; Lee, Sung Ho; Cho, Sera; Lee, Ik-Soo; Kang, Bok Yun; Choi, Hyun Jin

    2013-10-01

    Nuclear factor erythroid 2-related factor 2 (Nrf2) is a key transcriptional regulator for the protection of cells against oxidative and xenobiotic stresses. Recent studies have demonstrated that high constitutive expression of Nrf2 is observed in many types of cancer cells showing resistance to anti-cancer drugs, suggesting that the suppression of overexpressed Nrf2 could be an attractive therapeutic strategy to overcome cancer drug resistance. In the present study, we aimed to find small molecule compounds that enhance the sensitivity of tumor cells to cisplatin induced cytotoxicity by suppressing Nrf2-mediated defense mechanism. A549 lung cancer cells were shown to be more resistant to the anti-cancer drug cisplatin than HEK293 cells, with higher Nrf2 signaling activity; constitutively high amounts of Nrf2-downstream target proteins were observed in A549 cells. Among the three chalcone derivatives 4-methoxy-chalcone (4-MC), hesperidin methylchalcone, and neohesperidin dihydrochalcone, 4-MC was found to suppress transcriptional activity of Nrf2 in A549 cells but to activate it in HEK293 cells. 4-MC was also shown to down-regulate expression of Nrf2 and the downstream phase II detoxifying enzyme NQO1 in A549 cells. The PI3K/Akt pathway was found to be involved in the 4-MC-induced inhibition of Nrf2/ARE activity in A549 cells. This inhibition of Nrf2 signaling results in the accelerated generation of reactive oxygen species and exacerbation of cytotoxicity in cisplatin-treated A549 cells. Taken together, these results suggest that the small molecule compound 4-MC could be used to enhance the sensitivity of tumor cells to the therapeutic effect of cisplatin through the regulation of Nrf2/ARE signaling.

  12. Nrf2 activation ameliorates cytotoxic effects of arsenic trioxide in acute promyelocytic leukemia cells through increased glutathione levels and arsenic efflux from cells

    DOE Office of Scientific and Technical Information (OSTI.GOV)

    Nishimoto, Shoichi; Suzuki, Toshihiro; Koike, Shin

    Carnosic acid (CA), a phenolic diterpene isolated from Rosmarinus officinalis, has been shown to activate nuclear transcription factor E2-related factor 2 (Nrf2), which plays a central role in cytoprotective responses to oxidative and electrophilic stress. Recently, the Nrf2-Kelch ECH associating protein 1 (Keap1) pathway has been associated with cancer drug resistance attributable to modulation of the expression and activation of antioxidant and detoxification enzymes. However, the exact mechanisms by which Nrf2 activation results in chemoresistance are insufficiently understood to date. This study investigated the mechanisms by which the cytotoxic effects of arsenic trioxide (ATO), an anticancer drug, were decreased inmore » acute promyelocytic leukemia cells treated with CA, a typical activator of Nrf2 used to stimulate the Nrf2/Keap1 system. Our findings suggest that arsenic is non-enzymatically incorporated into NB4 cells and forms complexes that are dependent on intracellular glutathione (GSH) concentrations. In addition, the arsenic complexes are recognized as substrates by multidrug resistance proteins and subsequently excreted from the cells. Therefore, Nrf2-associated activation of the GSH biosynthetic pathway, followed by increased levels of intracellular GSH, are key mechanisms underlying accelerated arsenic efflux and attenuation of the cytotoxic effects of ATO. - Highlights: • Nrf2 activation attenuates the effect of arsenic trioxide to acute promyelocytic leukemia cells. • The sensitivity of arsenic trioxide to NB4 cells was dependent on efflux rate of arsenic. • Activation of the GSH biosynthesis is essential in Nrf2-regulated responses for arsenic efflux.« less

  13. Benznidazole, the trypanocidal drug used for Chagas disease, induces hepatic NRF2 activation and attenuates the inflammatory response in a murine model of sepsis

    DOE Office of Scientific and Technical Information (OSTI.GOV)

    Lambertucci, Flavia

    Molecular mechanisms on sepsis progression are linked to the imbalance between reactive oxygen species (ROS) production and cellular antioxidant capacity. Previous studies demonstrated that benznidazole (BZL), known for its antiparasitic action on Trypanosoma cruzi, has immunomodulatory effects, increasing survival in C57BL/6 mice in a model of polymicrobial sepsis induced by cecal ligation and puncture (CLP). The mechanism by which BZL inhibits inflammatory response in sepsis is poorly understood. Also, our group recently reported that BZL is able to activate the nuclear factor erytroide-derived 2-Like 2 (NRF2) in vitro. The aim of the present work was to delineate the beneficial rolemore » of BZL during sepsis, analyzing its effects on the cellular redox status and the possible link to the innate immunity receptor TLR4. Specifically, we analyzed the effect of BZL on Nrf2 regulation and TLR4 expression in liver of mice 24 hours post-CLP. BZL was able to induce NRF2 nuclear protein localization in CLP mice. Also, we found that protein kinase C (PKC) is involved in the NRF2 nuclear accumulation and induction of its target genes. In addition, BZL prompted a reduction in hepatic CLP-induced TLR4 protein membrane localization, evidencing its immunomodulatory effects. Together, our results demonstrate that BZL induces hepatic NRF2 activation with the concomitant increase in the antioxidant defenses, and the attenuation of inflammatory response, in part, by inhibiting TLR4 expression in a murine model of sepsis. - Highlights: • BZL improves survival rate after polymicrobial sepsis • BZL enhances hepatic NRF2 nuclear accumulation in a model of sepsis, in part, by a mechanism dependent on PKC activation • BZL-enhanced NRF2 induction regulates antioxidant enzymes and increases antioxidant cellular defenses in sepsis • BZL blocks liver ROS production and ROS-induced TLR4 plasma membrane expression in septic mice.« less

  14. Organic extract contaminants from drinking water activate Nrf2-mediated antioxidant response in a human cell line.

    PubMed

    Wang, Shu; Zhang, Hao; Zheng, Weiwei; Wang, Xia; Andersen, Melvin E; Pi, Jingbo; He, Gengsheng; Qu, Weidong

    2013-05-07

    Traditional risk assessment methods face challenges in estimating risks from drinking waters that contain low-levels of large numbers of contaminants. Here, we evaluate the toxicity of organic contaminant (OC) extracts from drinking water by examining activation of nuclear factor E2-related factor 2 (Nrf2)-mediated antioxidant response. In HepG2 cells, the Nrf2-mediated antioxidant response-measured as Nrf2 protein accumulation, expression of antioxidant response element (ARE)-regulated genes and ARE-luciferase reporter gene assays were activated by OC extracts from drinking water sources that detected 25 compounds in 9 classification groups. Individual OCs induced oxidative stress at concentrations much higher than their environmental levels; however, mixtures of contaminants induced oxidative stress response at only 8 times the environmental levels. Additionally, a synthetic OC mixture prepared based on the contamination profiling of drinking water induced ARE activity to the same extent as the real-world mixture, reinforcing our conclusion that these mixture exposures produce responses relevant for human exposure situations. Our study tested the possibility of assessing toxicity of OCs of drinking water using a specific ARE-pathway measurement. This approach should be broadly useful in assisting risk assessment of mixed environmental exposure.

  15. Novel function of transcription factor Nrf2 as an inhibitor of RON tyrosine kinase receptor-mediated cancer cell invasion.

    PubMed

    Thangasamy, Amalraj; Rogge, Jessica; Krishnegowda, Naveen K; Freeman, James W; Ammanamanchi, Sudhakar

    2011-09-16

    Recepteur d' origine nantais (RON), a tyrosine kinase receptor, is aberrantly expressed in human tumors and promotes cancer cell invasion. RON receptor activation is also associated with resistance to tamoxifen treatment in breast cancer cells. Nrf2 is a positive regulator of cytoprotective genes. Using chromatin immunoprecipitation (ChIP) and site-directed mutagenesis studies of the RON promoter, we identified Nrf2 as a negative regulator of RON gene expression. High Nrf2 and low RON expression was observed in normal mammary tissue whereas high RON and low or undetectable expression of Nrf2 was observed in breast tumors. The Nrf2 inducer sulforaphane (SFN) as well as ectopic Nrf2 expression or knock-down of the Nrf2 negative regulator keap1, which stabilizes Nrf2, inhibited RON expression and invasion of carcinoma cells. Consequently, our studies identified a novel functional role for Nrf2 as a "repressor" and RON kinase as a molecular target of SFN, which mediates the anti-tumor effects of SFN. These results are not limited to breast cancer cells since the Nrf2 inducer SFN stabilized Nrf2 and inhibited RON expression in carcinoma cells from various tumor types.

  16. Baicalin Ameliorates Experimental Liver Cholestasis in Mice by Modulation of Oxidative Stress, Inflammation, and NRF2 Transcription Factor

    PubMed Central

    Feng, Xiaowen; Zhang, Feng; Xie, Haiyang

    2017-01-01

    Experimental cholestatic liver fibrosis was performed by bile duct ligation (BDL) in mice, and significant liver injury was observed in 15 days. Administration of baicalin in mice significantly ameliorates liver fibrosis. Experimental cholestatic liver fibrosis was associated with induced gene expression of fibrotic markers such as collagen I, fibronectin, alpha smooth muscle actin (SMA), and connective tissue growth factor (CTGF); increased inflammatory cytokines (TNFα, MIP1α, IL1β, and MIP2); increased oxidative stress and reactive oxygen species- (ROS-) inducing enzymes (NOX2 and iNOS); dysfunctional mitochondrial electron chain complexes; and apoptotic/necrotic cell death markers (DNA fragmentation, caspase 3 activity, and PARP activity). Baicalin administration on alternate day reduced fibrosis along with profibrotic gene expression, proinflammatory cytokines, oxidative stress, and cell death whereas improving the function of mitochondrial electron transport chain. We observed baicalin enhanced NRF2 activation by nuclear translocation and induced its target genes HO-1 and GCLM, thus enhancing antioxidant defense. Interplay of oxidative stress/inflammation and NRF2 were key players for baicalin-mediated protection. Stellate cell activation is crucial for initiation of fibrosis. Baicalin alleviated stellate cell activation and modulated TIMP1, SMA, collagen 1, and fibronectin in vitro. This study indicates that baicalin might be beneficial for reducing inflammation and fibrosis in liver injury models. PMID:28757911

  17. β-Cryptoxanthin ameliorates metabolic risk factors by regulating NF-κB and Nrf2 pathways in insulin resistance induced by high-fat diet in rodents.

    PubMed

    Sahin, Kazim; Orhan, Cemal; Akdemir, Fatih; Tuzcu, Mehmet; Sahin, Nurhan; Yılmaz, Ismet; Juturu, Vijaya

    2017-09-01

    The aim of this experiment was to determine the effects of β-cryptoxanthin (BCX) on the cardiometabolic health risk factors and NF-κB and Nrf2 pathway in insulin resistance induced by high-fat diet (HFD) in rodents. Twenty-eight Sprague-Dawley rats were allocated into four groups: (1) Control, rats fed a standard diet for 12 weeks; (2) BCX, rats fed a standard diet and supplemented with BCX (2.5 mg/kg BW) for 12 weeks; (3) HFD, rats fed a HFD for 12 weeks, (4) HFD + BCX, rats fed a HFD and supplemented with BCX for 12 weeks. BCX reduced cardio-metabolic health markers and decreased inflammatory markers (P < 0.001). Rats fed a HFD had the lower total antioxidant capacity and antioxidant enzymes activities and higher MDA concentration than control rats (P < 0.001 for all). Comparing with the HFD group, BCX in combination with HFD inhibited liver NF-κB and TNF-α expression by 22% and 14% and enhanced liver Nrf2, HO-1, PPAR-α, and p-IRS-1 by 1.43, 1.41, 3.53, and 1.33 fold, respectively (P < 0.001). Furthermore, in adipose tissue, BCX up-regulated Nrf2, HO-1, PPAR-α, and p-IRS-1 expression, whereas, down-regulated NF-κB and TNF-α expression. In conclusion, BCX decreased visceral fat and cardiometabolic health risk factors through modulating expressions of nuclear transcription factors. Copyright © 2017 Elsevier Ltd. All rights reserved.

  18. Protective Effect of Decursin Extracted from Angelica gigas in Male Infertility via Nrf2/HO-1 Signaling Pathway.

    PubMed

    Bae, Woong Jin; Ha, U Syn; Choi, Jin Bong; Kim, Kang Sup; Kim, Su Jin; Cho, Hyuk Jin; Hong, Sung Hoo; Lee, Ji Youl; Wang, Zhiping; Hwang, Sung Yeoun; Kim, Sae Woong

    2016-01-01

    Higher testicular temperature results in altered spermatogenesis due to heat-related oxidative stress. We examined the effects of decursin extracted from Angelica gigas Nakai on antioxidant activity in vitro and in a cryptorchidism-induced infertility rat model. TM3 Leydig cell viability was measured based on oxidative stress according to treatment. Either distilled water or AG 400 mg/kg of A. gigas extract was administered orally for 4 weeks after unilateral cryptorchidism was induced. After 1, 2, and 4 weeks, six rats from the control group and six rats from treatment group were sacrificed. Testicular weight, semen quality, antioxidant activities, nuclear factor erythroid 2-related factor 2 (Nrf2) protein, and mRNA expression of Nrf2-regulated genes were analyzed. Treatment with A. gigas extract (1) protected TM3 cells against oxidative stress in a dose-dependent manner, (2) improved the mean weight of the cryptorchid testis, (3) maintained sperm counts, motility, and spermatogenic cell density, (4) decreased levels of 8-hydroxy-2-deoxyguanosine (8-OHdG) and increased levels of superoxide dismutase (SOD), (5) significantly increased Nrf2 and heme oxygenase-1 (HO-1), and (6) significantly decreased apoptosis. This study suggests that decursin extracted from A. gigas is a supplemental agent that can reduce oxidative stress by Nrf2-mediated upregulation of HO-1 in rat experimentally induced unilateral cryptorchidism and may improve cryptorchidism-induced infertility.

  19. Methane ameliorates spinal cord ischemia-reperfusion injury in rats: Antioxidant, anti-inflammatory and anti-apoptotic activity mediated by Nrf2 activation.

    PubMed

    Wang, Liping; Yao, Ying; He, Rong; Meng, Yan; Li, Na; Zhang, Dan; Xu, Jiajun; Chen, Ouyang; Cui, Jin; Bian, Jinjun; Zhang, Yan; Chen, Guozhong; Deng, Xiaoming

    2017-02-01

    Methane is reported to have antioxidant, anti-inflammatory and anti-apoptotic properties. We investigated the potential neuroprotective effects of methane-rich saline (MS) on spinal cord ischemia-reperfusion injury and determined that its therapeutic benefits are associated with the activation of nuclear factor erythroid 2-related factor 2 (Nrf2). Rats received 9min of spinal cord ischemia induced by occlusion of the descending thoracic aorta plus systemic hypotension followed by a single MS treatment (10ml/kg, ip) and 72h reperfusion. MS treatment attenuated motor sensory deficits and produced high concentrations of methane in spinal cords during reperfusion, which increased Nrf2 expression and transcriptional activity in neurons, microglia and astrocytes in the ventral, intermediate and dorsal gray matter of lumbar segments. Heme oxygenase-1, superoxide dismutase, catalase and glutathione were upregulated; and glutathione disulfide, superoxide, hydrogen peroxide, malondialdehyde, 8-hydroxy-2-deoxyguanosine and 3-nitrotyrosine were downregulated in MS-treated spinal cords. MS treatment reduced neuronal apoptosis in gray matter zones, which was consistent with the suppression of cytochrome c release to the cytosol from the mitochondria and the activation of caspase-9 and -3. Throughout the gray matter, the activation of microglia and astrocytes was inhibited; the nuclear accumulation of phosphorylated nuclear factor-kappa B p65 was reduced; and tumor necrosis factor α, interleukin 1β, chemokine (C-X-C motif) ligand 1, intercellular adhesion molecule 1 and myeloperoxidase were decreased. MS treatment attenuated blood-spinal cord barrier dysfunction by preventing the expression and activity of matrix metallopeptidase-9 and disrupting tight junction proteins. Consecutive intrathecal injection of specific siRNAs targeting Nrf2 at 24-h intervals 3 days before ischemia reduced the beneficial effects of MS. Our data indicate that MS treatment prevents IR-induced spinal

  20. Lack of association between nuclear factor erythroid-derived 2-like 2 promoter gene polymorphisms and oxidative stress biomarkers in amyotrophic lateral sclerosis patients.

    PubMed

    LoGerfo, Annalisa; Chico, Lucia; Borgia, Loredana; Petrozzi, Lucia; Rocchi, Anna; D'Amelio, Antonia; Carlesi, Cecilia; Caldarazzo Ienco, Elena; Mancuso, Michelangelo; Siciliano, Gabriele

    2014-01-01

    Oxidative stress involvement has been strongly hypothesized among the possible pathogenic mechanisms of motor neuron degeneration in amyotrophic lateral sclerosis (ALS). The intracellular redox balance is finely modulated by numerous complex mechanisms critical for cellular functions, among which the nuclear factor erythroid-derived 2-like 2 (NFE2L2/Nrf2) pathways. We genotyped, in a cohort of ALS patients (n = 145) and healthy controls (n = 168), three SNPs in Nrf2 gene promoter: -653 A/G, -651 G/A, and -617 C/A and evaluated, in a subset (n = 73) of patients, advanced oxidation protein products (AOPP), iron-reducing ability of plasma (FRAP), and plasma thiols (-SH) as oxidative damage peripheral biomarkers. Nrf2 polymorphisms were not different among patients and controls. Increased levels of AOPP (P < 0.05) and decreased levels of FRAP (P < 0.001) have been observed in ALS patients compared with controls, but no difference in -SH values was found. Furthermore, no association was found between biochemical markers of redox balance and Nrf2 polymorphisms. These data confirm an altered redox balance in ALS and indicate that, while being abnormally modified compared to controls, the oxidative stress biomarkers assessed in this study are independent from the -653 A/G, -651 G/A, and -617 C/A Nrf2 SNPs in ALS patients.

  1. Nrf2 Activation Protects against Solar-Simulated Ultraviolet Radiation in Mice and Humans.

    PubMed

    Knatko, Elena V; Ibbotson, Sally H; Zhang, Ying; Higgins, Maureen; Fahey, Jed W; Talalay, Paul; Dawe, Robert S; Ferguson, James; Huang, Jeffrey T-J; Clarke, Rosemary; Zheng, Suqing; Saito, Akira; Kalra, Sukirti; Benedict, Andrea L; Honda, Tadashi; Proby, Charlotte M; Dinkova-Kostova, Albena T

    2015-06-01

    The transcription factor Nrf2 determines the ability to adapt and survive under conditions of electrophilic, oxidative, and inflammatory stress by regulating the expression of elaborate networks comprising nearly 500 genes encoding proteins with versatile cytoprotective functions. In mice, disruption of Nrf2 increases susceptibility to carcinogens and accelerates disease pathogenesis. Paradoxically, Nrf2 is upregulated in established human tumors, but whether this upregulation drives carcinogenesis is not known. Here we show that the incidence, multiplicity, and burden of solar-simulated UV radiation-mediated cutaneous tumors that form in SKH-1 hairless mice in which Nrf2 is genetically constitutively activated are lower than those that arise in their wild-type counterparts. Pharmacologic Nrf2 activation by topical biweekly applications of small (40 nmol) quantities of the potent bis(cyano enone) inducer TBE-31 has a similar protective effect against solar-simulated UV radiation in animals receiving long-term treatment with the immunosuppressive agent azathioprine. Genetic or pharmacologic Nrf2 activation lowers the expression of the pro-inflammatory factors IL6 and IL1β, and COX2 after acute exposure of mice to UV radiation. In healthy human subjects, topical applications of extracts delivering the Nrf2 activator sulforaphane reduced the degree of solar-simulated UV radiation-induced skin erythema, a quantifiable surrogate endpoint for cutaneous damage and skin cancer risk. Collectively, these data show that Nrf2 is not a driver for tumorigenesis even upon exposure to a very potent and complete carcinogen and strongly suggest that the frequent activation of Nrf2 in established human tumors is a marker of metabolic adaptation. ©2015 American Association for Cancer Research.

  2. Nrf2 activation protects against solar-simulated ultraviolet radiation in mice and humans

    PubMed Central

    Knatko, Elena V.; Ibbotson, Sally H.; Zhang, Ying; Higgins, Maureen; Fahey, Jed W.; Talalay, Paul; Dawe, Robert S.; Ferguson, James; Huang, Jeffrey T.-J.; Clarke, Rosemary; Zheng, Suqing; Saito, Akira; Kalra, Sukirti; Benedict, Andrea L.; Honda, Tadashi; Proby, Charlotte M.; Dinkova-Kostova, Albena T.

    2015-01-01

    The transcription factor Nrf2 determines the ability to adapt and survive under conditions of electrophilic, oxidative and inflammatory stress by regulating the expression of elaborate networks comprising nearly 500 genes encoding proteins with versatile cytoprotective functions. In mice, disruption of Nrf2 increases susceptibility to carcinogens and accelerates disease pathogenesis. Paradoxically, Nrf2 is upregulated in established human tumors, but whether this upregulation drives carcinogenesis is not known. Here we show that the incidence, multiplicity and burden of solar-simulated UV radiation-mediated cutaneous tumors that form in SKH-1 hairless mice in which Nrf2 is genetically constitutively activated, are lower than those that arise in their wild-type counterparts. Pharmacological Nrf2 activation by topical bi-weekly applications of small (40 nmol) quantities of the potent bis(cyano enone) inducer TBE-31 has a similar protective effect against solar-simulated UV radiation in animals receiving long-term treatment with the immunosuppressive agent azathioprine. Genetic or pharmacological Nrf2 activation lowers the expression of the pro-inflammatory factors interleukin (IL)-6 and IL-1β, and cyclooxygenase (COX)-2 after acute exposure of mice to UV radiation. In healthy human subjects, topical applications of extracts delivering the Nrf2 activator sulforaphane, reduced the degree of solar-simulated UV radiation-induced skin erythema, a quantifiable surrogate end-point for cutaneous damage and skin cancer risk. Collectively, these data show that Nrf2 is not a driver for tumorigenesis even upon exposure to a very potent and complete carcinogen, and strongly suggest that the frequent activation of Nrf2 in established human tumors is a marker of metabolic adaptation. PMID:25804610

  3. Curcumin mitigates axonal injury and neuronal cell apoptosis through the PERK/Nrf2 signaling pathway following diffuse axonal injury.

    PubMed

    Huang, Tingqin; Zhao, Junjie; Guo, Dan; Pang, Honggang; Zhao, Yonglin; Song, Jinning

    2018-05-23

    Diffuse axonal injury (DAI) accounts for more than 50% of all traumatic brain injury. In response to the mechanical damage associated with DAI, the abnormal proteins produced in the neurons and axons, namely, β-APP and p-tau, induce endoplasmic reticulum (ER) stress. Curcumin, a major component extracted from the rhizome of Curcuma longa, has shown potent anti-inflammatory, antioxidant, anti-infection, and antitumor activity in previous studies. Moreover, curcumin is an activator of nuclear factor-erythroid 2-related factor 2 (Nrf2) and promotes its nuclear translocation. In this study, we evaluated the therapeutic potential of curcumin for the treatment of DAI and investigated the mechanisms underlying the protective effects of curcumin against neural cell death and axonal injury after DAI. Rats subjected to a model of DAI by head rotational acceleration were treated with vehicle or curcumin to evaluate the effect of curcumin on neuronal and axonal injury. We observed that curcumin (20 mg/kg intraperitoneal) administered 1 h after DAI induction alleviated the aggregation of p-tau and β-APP in neurons, reduced ER-stress-related cell apoptosis, and ameliorated neurological deficits. Further investigation showed that the protective effect of curcumin in DAI was mediated by the PERK/Nrf2 pathway. Curcumin promoted PERK phosphorylation, and then Nrf2 dissociated from Keap1 and was translocated to the nucleus, which activated ATF4, an important bZIP transcription factor that maintains intracellular homeostasis, but inhibited the CHOP, a hallmark of ER stress and ER-associated programmed cell death. In summary, we demonstrate for the first time that curcumin confers protection against abnormal proteins and neuronal apoptosis after DAI, that the process is mediated by strengthening of the unfolded protein response to overcome ER stress, and that the protective effect of curcumin against DAI is dependent on the activation of Nrf2.

  4. Nrf2/Keap1 system regulates vascular smooth muscle cell apoptosis for vascular homeostasis: role in neointimal formation after vascular injury

    PubMed Central

    Ashino, Takashi; Yamamoto, Masayuki; Numazawa, Satoshi

    2016-01-01

    Abnormal increases in vascular smooth muscle cells (VSMCs) in the intimal region after a vascular injury is a key event in developing neointimal hyperplasia. To maintain vascular function, proliferation and apoptosis of VSMCs is tightly controlled during vascular remodeling. NF-E2-related factor 2 (Nrf2)/Kelch-like ECH-associated protein 1 (Keap1) system, a key component of the oxidative stress response that acts in maintaining homeostasis, plays an important role in neointimal hyperplasia after a vascular injury; however, the role of Nrf2/Keap1 in VSMC apoptosis has not been clarified. Here we report that 14 days after arterial injury in mice, TUNEL-positive VSMCs are detected in both the neointimal and medial layers. These layers contain cells expressing high levels of Nrf2 but low Keap1 expression. In VSMCs, Keap1 depletion induces features of apoptosis, such as positive TUNEL staining and annexin V binding. These changes are associated with an increased expression of nuclear Nrf2. Simultaneous Nrf2 depletion inhibits Keap1 depletion-induced apoptosis. At 14 days after the vascular injury, Nrf2-deficient mice demonstrated fewer TUNEL-positive cells and increased neointimal formation in the neointimal and medial areas. The results suggest that the Nrf2/Keap1 system regulates VSMC apoptosis during neointimal formation, thereby inhibiting neointimal hyperplasia after a vascular injury. PMID:27198574

  5. Induction of activation of the antioxidant response element and stabilization of Nrf2 by 3-(3-pyridylmethylidene)-2-indolinone (PMID) confers protection against oxidative stress-induced cell death

    DOE Office of Scientific and Technical Information (OSTI.GOV)

    Yao, Jia-Wei; Beijing Institute of Radiation Medicine, Beijing 100850; Liu, Jing

    2012-03-01

    The antioxidant response elements (ARE) are a cis-acting enhancer sequence located in regulatory regions of antioxidant and detoxifying genes. Nuclear factor (erythroid-derived 2)-like 2 (Nrf2) is a member of the Cap ‘n’ Collar family of transcription factors that binds to the ARE and regulates the transcription of specific ARE-containing genes. Under oxidative stress, Nrf2/ARE induction is fundamental to defense against reactive oxygen species (ROS) and serves as a key factor in the protection against toxic xenobiotics. 3-(3-Pyridylmethylidene)-2-Indolinone (PMID) is a derivative of 2-indolinone compounds which act as protein kinase inhibitors and show anti-tumor activity. However, the role of PMID inmore » the oxidative stress remains unknown. In the present study, we showed that PMID induced the activation of ARE-mediated transcription, increased the DNA-binding activity of Nrf2 and then up-regulated the expression of antioxidant genes such as HO-1, SOD, and NQO1. The level of Nrf2 protein was increased in cells treated with PMID by a post-transcriptional mechanism. Under CHX treatment, the stability of Nrf2 protein was enhanced by PMID with decreased turnover rate. We showed that PMID reduced the ubiquitination of Nrf2 and disrupted the Cullin3 (Cul3)-Keap1 interaction. Furthermore, cells treated with PMID showed resistance to cytotoxicity by H{sub 2}O{sub 2} and pro-oxidant 6-OHDA. PMID also up-regulated the antioxidant level in BALB/c mice. Taken together, the compound PMID induces the ARE-mediated gene expression through stabilization of Nrf2 protein and activation of Nrf2/ARE pathway and protects against oxidative stress-mediated cell death. -- Highlights: ► PMID up-regulates ARE-mediated antioxidant gene expression in vitro and in vivo. ► PMID enhances the stabilization of Nrf2 protein, decreasing Nrf2 turnover rate. ► PMID disrupted the Cullin3 (Cul3)-Keap1 interaction. ► PMID protects against cell death induced by H{sub 2}O{sub 2} and pro

  6. Acrylamide-induced oxidative stress and inflammatory response are alleviated by N-acetylcysteine in PC12 cells: Involvement of the crosstalk between Nrf2 and NF-κB pathways regulated by MAPKs.

    PubMed

    Pan, Xiaoqi; Wu, Xu; Yan, Dandan; Peng, Cheng; Rao, Chaolong; Yan, Hong

    2018-05-15

    Acrylamide (ACR) is a classic neurotoxin in animals and humans. However, the mechanism underlying ACR neurotoxicity remains controversial, and effective prevention and treatment measures against this condition are scarce. This study focused on clarifying the crosstalk between the involved signaling pathways in ACR-induced oxidative stress and inflammatory response and investigating the protective effect of antioxidant N-acetylcysteine (NAC) against ACR in PC12 cells. Results revealed that ACR exposure led to oxidative stress characterized by significant increase in reactive oxygen species (ROS) and malondialdehyde (MDA) levels and glutathione (GSH) consumption. Inflammatory response was observed based on the dose-dependently increased levels of pro-inflammatory cytokines tumor necrosis factor-α (TNF-α) and interleukin 6 (IL-6). NAC attenuated ACR-induced enhancement of MDA and ROS levels and TNF-α generation. In addition, ACR activated nuclear transcription factor E2-related factor 2 (Nrf2) and nuclear factor-κB (NF-κB) signaling pathways. Knockdown of Nrf2 by siRNA significantly blocked the increased NF-κB p65 protein expression in ACR-treated PC12 cells. Down-regulation of NF-κB by specific inhibitor BAY11-7082 similarly reduced ACR-induced increase in Nrf2 protein expression. NAC treatment increased Nrf2 expression and suppressed NF-κB p65 expression to ameliorate oxidative stress and inflammatory response caused by ACR. Further results showed that mitogen-activated protein kinases (MAPKs) pathway was activated prior to the activation of Nrf2 and NF-κB pathways. Inhibition of MAPKs blocked Nrf2 and NF-κB pathways. Collectively, ACR activated Nrf2 and NF-κB pathways which were regulated by MAPKs. A crosstalk between Nrf2 and NF-κB pathways existed in ACR-induced cell damage. NAC protected against oxidative damage and inflammatory response induced by ACR by activating Nrf2 and inhibiting NF-κB pathways in PC12 cells. Copyright © 2018 Elsevier B

  7. Epigenetic modifications of triterpenoid ursolic acid in activating Nrf2 and blocking cellular transformation of mouse epidermal cells

    PubMed Central

    Kim, Hyuck; Ramirez, Christina N.; Su, Zheng-Yuan; Kong, Ah-Ng Tony

    2016-01-01

    Ursolic acid (UA), a well-known natural triterpenoid found in abundance in blueberries, cranberries and apple peels, has been reported to possess many beneficial health effects. These effects include anti-cancer activity in various cancers, such as skin cancer. Skin cancer is the most common cancer in the world. Nuclear factor E2-related factor 2 (Nrf2) is a master regulator of anti-oxidative stress response with anti-carcinogenic activity against UV- and chemical-induced tumor formation in the skin. Recent studies show that epigenetic modifications of Nrf2 play an important role in cancer prevention. However the epigenetic impact of UA on Nrf2 signaling remains poorly understood in skin cancer. In this study, we investigated the epigenetic effects of UA on mouse epidermal JB6 P+ cells. UA inhibited cellular transformation by 12-O-tetradecanoylphorbol-13-acetate (TPA) at a concentration at which the cytotoxicity was no more than 25%. Under this condition, UA induced the expression of the Nrf2-mediated detoxifying/antioxidant enzymes heme oxygenase-1 (HO-1), NAD(P)H:quinone oxidoreductase 1 (NQO1), and UDP-glucuronosyltransferase 1A1 (UGT1A1). DNA methylation analysis revealed that UA demethylated the first 15 CpG sites of the Nrf2 promoter region, which correlated with the re-expression of Nrf2. Furthermore, UA reduced the expression of epigenetic modifying enzymes, including the DNA methyltransferases (DNMTs) DNMT1 and DNMT3a and the histone deacetylases (HDACs) HDAC1, 2, 3, and 8 (Class I) and HDAC6 and 7 (Class II), and HDAC activity. Taken together, these results suggest that the epigenetic effects of the triterpenoid UA could potentially contribute to its beneficial effects, including the prevention of skin cancer. PMID:27260468

  8. Structural and functional characterization of Nrf2 degradation by glycogen synthase kinase 3/β-TrCP.

    PubMed

    Cuadrado, Antonio

    2015-11-01

    Nuclear factor (erythroid-derived 2)-like 2 (Nrf2) is a master regulator of cellular homeostasis that controls the expression of more than 1% of human genes related to biotransformation reactions, redox homeostasis, energetic metabolism, DNA repair, and proteostasis. Its activity has a tremendous impact on physiology and pathology and therefore it is very tightly regulated, mainly at the level of protein stability. In addition to the very well established regulation by the ubiquitin E3 ligase adapter Keap1, recent advances have identified a novel mechanism based on signaling pathways that regulate glycogen synthase kinse-3 (GSK-3). This kinase phosphorylates specific serine residues in the Neh6 domain of Nrf2 to create a degradation domain that is then recognized by the ubiquitin ligase adapter β-TrCP and tagged for proteasome degradation by a Cullin1/Rbx1 complex. Here we review the mechanistic elements and the signaling pathways that participate in this regulation by GSK-3/β-TrCP. These pathways include those activated by ligands of tyrosine kinase, G protein-coupled, metabotropic, and ionotropic receptors that activate phosphatidyl inositol 3-kinase (PI3K)/ATK and by the canonical WNT signaling pathway, where a fraction of Nrf2 interacts with Axin1/GSK-3. Considering that free Nrf2 protein is localized in the nucleus, we propose a model termed "double flux controller" to explain how Keap1 and β-TrCP coordinate the stability of Nrf2 in several scenarios. The GSK-3/β-TrCP axis provides a novel therapeutic strategy to modulate Nrf2 activity. Copyright © 2015 Elsevier Inc. All rights reserved.

  9. Protective role of Nrf2 against mechanical-stretch-induced apoptosis in mouse fibroblasts: a potential therapeutic target of mechanical-trauma-induced stress urinary incontinence.

    PubMed

    Li, Qiannan; Li, Bingshu; Liu, Cheng; Wang, Linlin; Tang, Jianming; Hong, Li

    2018-01-10

    We investigated the protective effect and underlying molecular mechanism of nuclear factor-E2-related factor 2 (Nrf2) against mechanical-stretch-induced apoptosis in mouse fibroblasts. Normal cells, Nrf2 silencing cells, and Nrf2 overexpressing cells were respectively divided into two groups-nonintervention and cyclic mechanical strain (CMS)-subjected to CMS of 5333 μ (1.0 Hz for 4 h), six groups in total (control, CMS, shNfe212, shNfe212 + CMS, LV-shNfe212, and LV-shNfe212 + CMS). After treatment, cell apoptosis; cell-cycle distribution; expressions of Nrf2, Bax, Bcl-2, Cyt-C, caspase-3, caspase-9, cleaved-caspase-3, and cleaved-caspase-9; mitochondrial membrane potential (ΔΨm); reactive oxygen species (ROS); and malondialdehyde (MDA) levels were measured. Thirty virgin female C57BL/6 mice were divided into two groups: control (without intervention) and vaginal distension (VD) groups, which underwent VD for 1 h with an 8-mm dilator (0.3 ml saline). Leak-point pressure (LPP) was tested on day 7 after VD; Nrf2 expression, apoptosis, and MDA levels were then measured in urethra and anterior vaginal wall. Mechanical stretch decreased Nrf2 messenger RNA (mRNA) and protein expressions. Overexpression of Nrf2 alleviated mechanical-stretch-induced cell apoptosis; S-phase arrest of cell cycle; up-regulation of Bax, cytochrome C (Cyt-C), ROS, MDA, ratio of cleaved-caspase-3/caspase-3 and cleaved-caspase-9/caspase-9; and exacerbated the decrease of Bcl2 and ΔΨm in L929 cells. On the contrary, silencing of Nrf2 showed opposite effects. Besides, VD reduced LPP levels and Nrf2 expression and increased cell apoptosis and MDA generation in the urethra and anterior vaginal wall. Nrf2 exhibits a protective role against mechanical-stretch -induced apoptosis on mouse fibroblasts, which might indicate a potential therapeutic target of mechanical-trauma-induced stress urinary incontinence (SUI).

  10. Activation of Nrf2 Reduces UVA-Mediated MMP-1 Upregulation via MAPK/AP-1 Signaling Cascades: The Photoprotective Effects of Sulforaphane and Hispidulin

    PubMed Central

    Chaiprasongsuk, Anyamanee; Lohakul, Jinaphat; Soontrapa, Kitipong; Sampattavanich, Somponnat; Akarasereenont, Pravit

    2017-01-01

    UVA irradiation plays a role in premature aging of the skin through triggering oxidative stress-associated stimulation of matrix metalloproteinase-1 (MMP-1) responsible for collagen degradation, a hallmark of photoaged skin. Compounds that can activate nuclear factor E2-related factor 2 (Nrf2), a transcription factor regulating antioxidant gene expression, should therefore serve as effective antiphotoaging agents. We investigated whether genetic silencing of Nrf2 could relieve UVA-mediated MMP-1 upregulation via activation of mitogen-activated protein kinase (MAPK)/activator protein 1 (AP-1) signaling using human keratinocyte cell line (HaCaT). Antiphotoaging effects of hispidulin (HPD) and sulforaphane (SFN) were assessed on their abilities to activate Nrf2 in controlling MMP-1 and collagen expressions in association with phosphorylation of MAPKs (extracellular signal-regulated kinase, c-Jun N-terminal kinase, and p38), c-Jun, and c-Fos, using the skin of BALB/c mice subjected to repetitive UVA irradiation. Our findings suggested that depletion of Nrf2 promoted both mRNA expression and activity of MMP-1 in the UVA-irradiated HaCaT cells. Treatment of Nrf2 knocked-down HaCaT cells with MAPK inhibitors significantly suppressed UVA-induced MMP-1 and AP-1 activities. Moreover, pretreatment of the mouse skin with HPD and SFN, which could activate Nrf2, provided protective effects against UVA-mediated MMP-1 induction and collagen depletion in correlation with the decreased levels of phosphorylated MAPKs, c-Jun, and c-Fos in the mouse skin. In conclusion, Nrf2 could influence UVA-mediated MMP-1 upregulation through the MAPK/AP-1 signaling cascades. HPD and SFN may therefore represent promising antiphotoaging candidates. PMID:28011874

  11. The NRF2-related interactome and regulome contain multifunctional proteins and fine-tuned autoregulatory loops.

    PubMed

    Papp, Diána; Lenti, Katalin; Módos, Dezső; Fazekas, Dávid; Dúl, Zoltán; Türei, Dénes; Földvári-Nagy, László; Nussinov, Ruth; Csermely, Péter; Korcsmáros, Tamás

    2012-06-21

    NRF2 is a well-known, master transcription factor (TF) of oxidative and xenobiotic stress responses. Recent studies uncovered an even wider regulatory role of NRF2 influencing carcinogenesis, inflammation and neurodegeneration. Prompted by these advances here we present a systems-level resource for NRF2 interactome and regulome that includes 289 protein-protein, 7469 TF-DNA and 85 miRNA interactions. As systems-level examples of NRF2-related signaling we identified regulatory loops of NRF2 interacting proteins (e.g., JNK1 and CBP) and a fine-tuned regulatory system, where 35 TFs regulated by NRF2 influence 63 miRNAs that down-regulate NRF2. The presented network and the uncovered regulatory loops may facilitate the development of efficient, NRF2-based therapeutic agents. Copyright © 2012 Federation of European Biochemical Societies. Published by Elsevier B.V. All rights reserved.

  12. PFOS induces adipogenesis and glucose uptake in association with activation of Nrf2 signaling pathway

    DOE Office of Scientific and Technical Information (OSTI.GOV)

    Xu, Jialin; Department of Biomedical and Pharmaceutical Sciences, University of Rhode Island, Kingston, RI 02881; Shimpi, Prajakta

    PFOS is a chemical of nearly ubiquitous exposure in humans. Recent studies have associated PFOS exposure to adipose tissue-related effects. The present study was to determine whether PFOS alters the process of adipogenesis and regulates insulin-stimulated glucose uptake in mouse and human preadipocytes. In murine-derived 3T3-L1 preadipocytes, PFOS enhanced hormone-induced differentiation to adipocytes and adipogenic gene expression, increased insulin-stimulated glucose uptake at concentrations ranging from 10 to 100 μM, and enhanced Glucose transporter type 4 and Insulin receptor substrate-1 expression. Nuclear factor (erythroid-derived 2)-like 2 (Nrf2), NAD(P)H dehydrogenase, quinone 1 and Glutamate-cysteine ligase, catalytic subunit were significantly induced in 3T3-L1more » cells treated with PFOS, along with a robust induction of Antioxidant Response Element (ARE) reporter in mouse embryonic fibroblasts isolated from ARE-hPAP transgenic mice by PFOS treatment. Chromatin immunoprecipitation assays further illustrated that PFOS increased Nrf2 binding to ARE sites in mouse Nqo1 promoter, suggesting that PFOS activated Nrf2 signaling in murine-derived preadipocytes. Additionally, PFOS administration in mice (100 μg/kg/day) induced adipogenic gene expression and activated Nrf2 signaling in epididymal white adipose tissue. Moreover, the treatment on human visceral preadipocytes illustrated that PFOS (5 and 50 μM) promoted adipogenesis and increased cellular lipid accumulation. It was observed that PFOS increased Nrf2 binding to ARE sites in association with Nrf2 signaling activation, induction of Peroxisome proliferator-activated receptor γ and CCAAT/enhancer-binding protein α expression, and increased adipogenesis. This study points to a potential role of PFOS in dysregulation of adipose tissue expandability, and warrants further investigations on the adverse effects of persistent pollutants on human health. - Highlights: • PFOS induces adipogenesis in

  13. Akt and ERK/Nrf2 activation by PUFA oxidation-derived aldehydes upregulates FABP4 expression in human macrophages.

    PubMed

    Lázaro, Iolanda; Ferré, Raimon; Masana, Lluís; Cabré, Anna

    2013-10-01

    In macrophages, adipocyte fatty acid-binding protein (FABP4) coordinates key events in oxidized LDL-induced foam cell formation, such as cholesterol trafficking and inflammatory responses. Nrf2 is a redox-sensitive transcription factor with antioxidant and anti-inflammatory properties. We investigated the involvement of the Nrf2 signaling pathway in FABP4-upregulation in response to aldehydes that are derived from polyunsaturated fatty acid (PUFA) oxidation. Using RT-PCR and western blotting, we found that the aldehyde 2,4-decadienal (2,4-DDE) produced a marked increase in FABP4 mRNA and protein levels. 2,4-DDE acts at the transcriptional level of FABP4 by promoting mRNA synthesis and prolonging the half-life of the de novo synthesized mRNA. 2,4-DDE consistently enhanced nuclear translocation of phosphorylated Nrf2, which was mediated by the activation of the Akt and ERK signaling pathways. A chromatin immunoprecipitation assay showed the in vivo binding of activated Nrf2 to a newly identified ARE site in the human FABP4 promoter. We propose an Akt and ERK/Nrf2-dependent FABP4 upregulation pathway in response to PUFA oxidation end-products in human macrophages. These results open a new avenue for putative therapeutic targets addressed to control atherogenesis. Copyright © 2013 Elsevier Ireland Ltd. All rights reserved.

  14. ROS signaling, oxidative stress and Nrf2 in pancreatic beta-cell function

    PubMed Central

    Pi, Jingbo; Zhang, Qiang; Fu, Jingqi; Woods, Courtney G.; Hou, Yongyong; Corkey, Barbara E; Collins, Sheila; Andersen, Melvin E.

    2009-01-01

    This review focuses on the emerging evidence that reactive oxygen species (ROS) derived from glucose metabolism, such as H2O2, act as metabolic signaling molecules for glucose-stimulated insulin secretion (GSIS) in pancreatic beta-cells. Particular emphasis is placed on the potential inhibitory role of endogenous antioxidants, which rise in response to oxidative stress, in glucose-triggered ROS and GSIS. We propose that cellular adaptive response to oxidative stress challenge, such as nuclear factor E2-related factor 2 (Nrf2)-mediated antioxidant induction, plays paradoxical roles in pancreatic beta-cell function. On the one hand, induction of antioxidant enzymes protects beta-cells from oxidative damage and possible cell death, thus minimizing oxidative damage-related impairment of insulin secretion. On the other hand, the induction of antioxidant enzymes by Nrf2 activation blunts glucose-triggered ROS signaling, thus resulting in reduced GSIS. These two premises are potentially relevant to impairment of beta-cells occurring in the late and early stage of Type 2 diabetes, respectively. In addition, we summarized our recent findings that persistent oxidative stress due to absence of uncoupling protein 2 activates cellular adaptive response which is associated with impaired pancreatic beta-cell function. PMID:19501608

  15. N-acetylcysteine Ameliorates Prostatitis via miR-141 Regulating Keap1/Nrf2 Signaling.

    PubMed

    Wang, Liang-Liang; Huang, Yu-Hua; Yan, Chun-Yin; Wei, Xue-Dong; Hou, Jian-Quan; Pu, Jin-Xian; Lv, Jin-Xing

    2016-04-01

    Chronic prostatitis was the most common type of prostatitis and oxidative stress was reported to be highly elevated in prostatitis patients. In this study, we determined the effect of N-acetylcysteine (NAC) on prostatitis and the molecular mechanism involved in it. Male Sprague-Dawley rats were divided into three groups: control group (group A, n = 20), carrageenan-induced chronic nonbacterial prostatitis (CNP) model group (group B, n = 20), and carrageenan-induced CNP model group with NAC injection (group C, n = 20). Eye score, locomotion score, inflammatory cell count, cyclooxygenase 2 (COX2) expression, and Evans blue were compared in these three groups. The expression of miR-141 was determined by quantitative real-time PCR (qRT-PCR). Moreover, protein expressions of Kelch-like ECH-associated protein-1 (Keap1) and nuclear factor erythroid-2 related factor 2 (Nrf2) and its target genes were examined by Western blot. Luciferase reporter assay was performed in RWPE-1 cells transfected miR-141 mimic or inhibitor and the plasmid carrying 3'-UTR of Keap1. The value of eye score, locomotion score, inflammatory cell count, and Evans blue were significantly decreased in group C, as well as the expression of COX2, when comparing to that of group B. These results indicated that NAC relieved the carrageenan-induced CNP. Further, we found that NAC increased the expression of miR-141 and activated the Keap1/Nrf2 signaling. Luciferase reporter assay revealed that miR-141 mimic could suppress the activity of Keap1 and stimulate the downstream target genes of Nrf2. In addition, miR-141 inhibitor could reduce the effect of NAC on prostatitis. NAC ameliorates the carrageenan-induced prostatitis and prostate inflammation pain through miR-141 regulating Keap1/Nrf2 signaling.

  16. Nrf2-Mediated Neuroprotection Against Recurrent Hypoglycemia Is Insufficient to Prevent Cognitive Impairment in a Rodent Model of Type 1 Diabetes.

    PubMed

    McNeilly, Alison D; Gallagher, Jennifer R; Dinkova-Kostova, Albena T; Hayes, John D; Sharkey, John; Ashford, Michael L J; McCrimmon, Rory J

    2016-10-01

    It remains uncertain whether recurrent nonsevere hypoglycemia (Hypo) results in long-term cognitive impairment in type 1 diabetes (T1D). This study tested the hypothesis that specifically in the T1D state, Hypo leads to cognitive impairment via a pathological response to oxidative stress. Wild-type (Control) and nuclear factor-erythroid 2 p45-related factor 2 (Nrf2) null mice were studied. Eight groups of mice (Control and Nrf2(-/-) ± T1D and ± Hypo) were subject to recurrent, twice-weekly, insulin or saline injections over 4 weeks, after which cognitive function was assessed and brain tissue analyzed. Recurrent moderate hypoglycemia in T1D, but not Control, mice significantly impaired cognitive performance, and this was associated with hippocampal oxidative damage and inflammation despite an enhanced expression of Nrf2 and its target genes Hmox1 and Nqo1 In Nrf2(-/-) mice, both T1D and Hypo independently resulted in impaired cognitive performance, and this was associated with oxidative cell damage and marked inflammation. Together, these data suggest that Hypo induces an Nrf2-dependent antioxidant response in the hippocampus, which counteracts oxidative damage. However, in T1D, this neuroprotective mechanism is insufficient to prevent neuronal oxidative damage, resulting in chronic deficits in working and long-term memory. © 2016 by the American Diabetes Association.

  17. Effect of cellular ubiquitin levels on the regulation of oxidative stress response and proteasome function via Nrf1

    DOE Office of Scientific and Technical Information (OSTI.GOV)

    Lee, Donghee; Ryu, Kwon-Yul

    The polyubiquitin genes Ubb and Ubc are upregulated under oxidative stress induced by arsenite [As(III)]. However, the role of ubiquitin (Ub) under As(III) exposure is not known in detail. In a previous study, we showed that the reduced viability observed in Ubc{sup −/−} mouse embryonic fibroblasts under As(III) exposure was not due to dysregulation of the Nrf2–Keap1 pathway, which prompted us to investigate another NFE2 family protein, nuclear factor erythroid 2-related factor 1 (Nrf1). In this study, we found that Ub deficiency due to Ubc knockdown in N2a cells reduced cell viability and proteasome activity under As(III) exposure. Furthermore, mRNAmore » levels of the proteasome subunit Psma1 were also reduced. In addition, Ub deficiency led to the nuclear accumulation of the p65 isoform of Nrf1 under As(III) exposure. Interestingly, the overexpression of p65-Nrf1 recapitulated the phenotypes of Ub-deficient N2a cells under As(III) exposure. On the other hand, Nrf1 knockdown suppressed the death of Ub-deficient N2a cells upon exposure to As(III). Therefore, the levels of p65-Nrf1 may play an important role in the maintenance of cell viability under oxidative stress induced by As(III). - Highlights: • N2a cells exhibit reduced viability upon exposure to As(III) via Ubc knockdown. • As(III)-induced proteasomal regulation is impaired in Ub-deficient N2a cells. • Ub deficiency leads to the nuclear accumulation of p65-Nrf1 under As(III) exposure. • p65 expression recapitulates As(III)-induced phenotypes of Ub-deficient N2a cells. • Nrf1 knockdown suppressed As(III)-induced death of Ub-deficient N2a cells.« less

  18. Negative transcriptional regulation of mitochondrial transcription factor A (TFAM) by nuclear TFAM

    DOE Office of Scientific and Technical Information (OSTI.GOV)

    Lee, Eun Jin; Kang, Young Cheol; Park, Wook-Ha

    2014-07-18

    Highlights: • TFAM localizes in nuclei and mitochondria of neuronal cells. • Nuclear TFAM does not bind the Tfam promoter. • Nuclear TFAM reduced the Tfam promoter activity via suppressing NRF-1 activity. • A novel self-negative feedback regulation of Tfam gene expression is explored. • FAM may play different roles depending on its subcellular localizations. - Abstract: The nuclear DNA-encoded mitochondrial transcription factor A (TFAM) is synthesized in cytoplasm and transported into mitochondria. TFAM enhances both transcription and replication of mitochondrial DNA. It is unclear, however, whether TFAM plays a role in regulating nuclear gene expression. Here, we demonstrated thatmore » TFAM was localized to the nucleus and mitochondria by immunostaining, subcellular fractionation, and TFAM-green fluorescent protein hybrid protein studies. In HT22 hippocampal neuronal cells, human TFAM (hTFAM) overexpression suppressed human Tfam promoter-mediated luciferase activity in a dose-dependent manner. The mitochondria targeting sequence-deficient hTFAM also repressed Tfam promoter activity to the same degree as hTFAM. It indicated that nuclear hTFAM suppressed Tfam expression without modulating mitochondrial activity. The repression required for nuclear respiratory factor-1 (NRF-1), but hTFAM did not bind to the NRF-1 binding site of its promoter. TFAM was co-immunoprecipitated with NRF-1. Taken together, we suggest that nuclear TFAM down-regulate its own gene expression as a NRF-1 repressor, showing that TFAM may play different roles depending on its subcellular localizations.« less

  19. Apigenin inhibits d-galactosamine/LPS-induced liver injury through upregulation of hepatic Nrf-2 and PPARγ expressions in mice.

    PubMed

    Zhou, Rui-Jun; Ye, Hua; Wang, Feng; Wang, Jun-Long; Xie, Mei-Lin

    2017-11-04

    Apigenin is a natural flavonoid compound widely distributed in a variety of vegetables, medicinal plants and health foods. This study aimed to examine the protective effect of apigenin against d-galactosamine (D-GalN)/lipopolysaccharide (LPS)-induced mouse liver injury and to investigate the potential biochemical mechanisms. The results showed that after oral administration of apigenin 100-200 mg/kg for 7 days, the levels of serum alanine aminotransferase and aspartate aminotransferase were decreased, and the severity of liver injury was alleviated. Importantly, apigenin pretreatment increased the levels of hepatic nuclear factor erythroid 2-related factor 2 (Nrf-2) and peroxisome proliferator-activated receptor γ (PPARγ) protein expressions as well as superoxide dismutase, catalase, glutathione S-transferase and glutathione reductase activities, decreased the levels of hepatic nuclear factor-κB (NF-κB) protein expression and tumor necrosis factor-α. These findings demonstrated that apigenin could prevent the D-GalN/LPS-induced liver injury in mice, and its mechanisms might be associated with the increments of Nrf-2-mediated antioxidative enzymes and modulation of PPARγ/NF-κB-mediated inflammation. Copyright © 2017 Elsevier Inc. All rights reserved.

  20. Small molecule activators of the Nrf2-HO-1 antioxidant axis modulate heme metabolism and inflammation in BV2 microglia cells.

    PubMed

    Foresti, Roberta; Bains, Sandip K; Pitchumony, Tamil Selvi; de Castro Brás, Lisandra E; Drago, Filippo; Dubois-Randé, Jean-Luc; Bucolo, Claudio; Motterlini, Roberto

    2013-10-01

    The nuclear factor erythroid derived 2-related factor 2 (Nrf2) and the antioxidant protein heme oxygenase-1 (HO-1) are crucial components of the cellular stress response. These two systems work together to combat oxidative stress and inflammation and are attractive drug targets for counteracting different pathologies, including neuroinflammation. We aimed to identify the most effective Nrf2/HO-1 activators that modulate the inflammatory response in microglia cells. In the present study, we searched the literature and selected 56 compounds reported to activate Nrf2 or HO-1 and analyzed them for HO-1 induction at 6 and 24h and cytotoxicity in BV2 microglial cells in vitro. Approximately 20 compounds up-regulated HO-1 at the concentrations tested (5-20 μM) with carnosol, supercurcumin, cobalt protoporphyrin-IX and dimethyl fumarate exhibiting the best induction/low cytotoxicity profile. Up-regulation of HO-1 by some compounds resulted in increased cellular bilirubin levels but did not augment the expression of proteins involved in heme synthesis (ALAS 1) or biliverdin reductase. Bilirubin production by HO-1 inducers correlated with their potency in inhibiting nitrite production after challenge with interferon-γ (INF-γ) or lipopolysaccharide (LPS). The compounds down-regulated the inflammatory response (TNF-α, PGE2 and nitrite) more strongly in cells challenged with INF-γ than LPS, and silencing HO-1 or Nrf2 with shRNA differentially affected the levels of inflammatory markers. These findings indicate that some small activators of Nrf2/HO-1 are effective modulators of microglia inflammation and highlight the chemical scaffolds that can serve for the synthesis of potent new derivatives to counteract neuroinflammation and neurodegeneration. Copyright © 2013 Elsevier Ltd. All rights reserved.

  1. Denitrosylation of HDAC2 by targeting Nrf2 restores glucocorticosteroid sensitivity in macrophages from COPD patients

    PubMed Central

    Malhotra, Deepti; Thimmulappa, Rajesh K.; Mercado, Nicolas; Ito, Kazuhiro; Kombairaju, Ponvijay; Kumar, Sarvesh; Ma, Jinfang; Feller-Kopman, David; Wise, Robert; Barnes, Peter; Biswal, Shyam

    2011-01-01

    Chronic obstructive pulmonary disease (COPD), which is caused primarily by cigarette smoking, is a major health problem worldwide. The progressive decline in lung function that occurs in COPD is a result of persistent inflammation of the airways and destruction of the lung parenchyma. Despite the key role of inflammation in the pathogenesis of COPD, treatment with corticosteroids — normally highly effective antiinflammatory drugs — has little therapeutic benefit. This corticosteroid resistance is largely caused by inactivation of histone deacetylase 2 (HDAC2), which is critical for the transrepressive activity of the glucocorticoid receptor (GR) that mediates the antiinflammatory effect of corticosteroids. Here, we show that in alveolar macrophages from patients with COPD, S-nitrosylation of HDAC2 is increased and that this abolishes its GR-transrepression activity and promotes corticosteroid insensitivity. Cys-262 and Cys-274 of HDAC2 were found to be the targets of S-nitrosylation, and exogenous glutathione treatment of macrophages from individuals with COPD restored HDAC2 activity. Treatment with sulforaphane, a small-molecule activator of the transcription factor nuclear factor erythroid 2–related factor 2 (NRF2), was also able to denitrosylate HDAC2, restoring dexamethasone sensitivity in alveolar macrophages from patients with COPD. These effects of sulforaphane were glutathione dependent. We conclude that NRF2 is a novel drug target for reversing corticosteroid resistance in COPD and other corticosteroid-resistant inflammatory diseases. PMID:22005302

  2. Cul3-mediated Nrf2 ubiquitination and antioxidant response element (ARE) activation are dependent on the partial molar volume at position 151 of Keap1.

    PubMed

    Eggler, Aimee L; Small, Evan; Hannink, Mark; Mesecar, Andrew D

    2009-07-29

    Nrf2 (nuclear factor erythroid 2-related factor 2) is a transcription factor that activates transcription of a battery of cytoprotective genes by binding to the ARE (antioxidant response element). Nrf2 is repressed by the cysteine-rich Keap1 (kelch-like ECH-associated protein 1) protein, which targets Nrf2 for ubiquitination and subsequent degradation by a Cul3 (cullin 3)-mediated ubiquitination complex. We find that modification of Cys(151) of human Keap1, by mutation to a tryptophan, relieves the repression by Keap1 and allows activation of the ARE by Nrf2. The Keap1 C151W substitution has a decreased affinity for Cul3, and can no longer serve to target Nrf2 for ubiquitination, though it retains its affinity for Nrf2. A series of 12 mutant Keap1 proteins, each containing a different residue at position 151, was constructed to explore the chemistry required for this effect. The series reveals that the extent to which Keap1 loses the ability to target Nrf2 for degradation, and hence the ability to repress ARE activation, correlates well with the partial molar volume of the residue. Other physico-chemical properties do not appear to contribute significantly to the effect. Based on this finding, a structural model is proposed whereby large residues at position 151 cause steric clashes that lead to alteration of the Keap1-Cul3 interaction. This model has significant implications for how electrophiles which modify Cys(151), disrupt the repressive function of Keap1.

  3. Ethanol Extract of Cirsium japonicum var. ussuriense Kitamura Exhibits the Activation of Nuclear Factor Erythroid 2-Related Factor 2-dependent Antioxidant Response Element and Protects Human Keratinocyte HaCaT Cells Against Oxidative DNA Damage.

    PubMed

    Yoo, Ok-Kyung; Choi, Bu Young; Park, Jin-Oh; Lee, Ji-Won; Park, Byoung-Kwon; Joo, Chul Gue; Heo, Hyo-Jung; Keum, Young-Sam

    2016-03-01

    Keratinocytes are constantly exposed to extracellular insults, such as ultraviolet B, toxic chemicals and mechanical stress, all of which can facilitate the aging of keratinocytes via the generation of intracellular reactive oxygen species (ROS). Nuclear factor erythroid 2-related factor 2 (Nrf2) is a transcription factor that plays a critical role in protecting keratinocytes against oxidants and xenobiotics by binding to the antioxidant response element (ARE), a cis-acting element existing in the promoter of most phase II cytoprotective genes. In the present study, we have attempted to find novel ethanol extract(s) of indigenous plants of Jeju island, Korea that can activate the Nrf2/ARE-dependent gene expression in human keratinocyte HaCaT cells. As a result, we identified that ethanol extract of Cirsium japonicum var. ussuriense Kitamura (ECJUK) elicited strong stimulatory effect on the ARE-dependent gene expression. Supporting this observation, we found that ECJUK induced the expression of Nrf2, hemoxygenase-1, and quinone oxidoreductase-1 and this event was correlated with Akt1 phosphorylation. We also found that ECJUK increased the intracellular reduced glutathione level and suppressed 12-O-tetradecanoylphorbol acetate-induced 8-hydroxyguanosine formation without affecting the overall viability. Collectively, our results provide evidence that ECJUK can protect against oxidative stress-mediated damages through the activation of Nrf2/ARE-dependent phase II cytoprotective gene expression.

  4. Carnosic Acid Induces Anti-Inflammatory Effects in Paraquat-Treated SH-SY5Y Cells Through a Mechanism Involving a Crosstalk Between the Nrf2/HO-1 Axis and NF-κB.

    PubMed

    de Oliveira, Marcos Roberto; de Souza, Izabel Cristina Custódio; Fürstenau, Cristina Ribas

    2018-01-01

    Carnosic acid (CA) is a phenolic diterpene obtained from Rosmarinus officinalis L. and has demonstrated cytoprotective properties in several experimental models. CA exerts antioxidant effects by upregulating the transcription factor nuclear factor erythroid 2-related factor 2 (Nrf2), which controls the expression of antioxidant and phase II detoxification enzymes. Heme oxygenase-1 (HO-1) expression is modulated by Nrf2 and has been demonstrated as part of the mechanism underlying the CA-induced cytoprotection. Nonetheless, it remains to be studied whether and how HO-1 would mediate CA-elicited anti-inflammatory effects. Therefore, we have investigated here whether and how CA would prevent paraquat (PQ)-induced inflammation-related alterations in human neuroblastoma SH-SY5Y cells. SH-SY5Y cells were pretreated for 12 h with CA at 1 μM before exposure to PQ for further 24 h. CA suppressed the PQ-induced alterations on the levels of interleukin-1β (IL-1β), tumor necrosis factor-α (TNF-α), and cyclooxygenase-2 (COX-2) through a mechanism involving the activation of the Nrf2/HO-1 axis. Furthermore, we observed a crosstalk between the Nrf2/HO-1 signaling pathway and the activation of the nuclear factor-κB (NF-κB) transcription factor, since administration of ZnPP IX (specific inhibitor of HO-1) or Nrf2 knockdown using small interfering RNA (siRNA) abolished the anti-inflammatory effects induced by CA. Moreover, administration of SN50 (specific inhibitor of NF-κB) inhibited the PQ-induced inflammation-related effects in SH-SY5Y cells. Therefore, CA exerted anti-inflammatory effects in SH-SY5Y cells through an Nrf2/HO-1 axis-dependent manner associated with downregulation of NF-κB.

  5. Role of Nrf2 antioxidant defense in mitigating cadmium-induced oxidative stress in the olfactory system of zebrafish

    DOE Office of Scientific and Technical Information (OSTI.GOV)

    Wang, Lu; Gallagher, Evan P., E-mail: evang3@uw.edu

    2013-01-15

    Exposure to trace metals can disrupt olfactory function in fish leading to a loss of behaviors critical to survival. Cadmium (Cd) is an olfactory toxicant that elicits cellular oxidative stress as a mechanism of toxicity while also inducing protective cellular antioxidant genes via activation of the nuclear factor (erythroid-derived 2)-like 2 (Nrf2) pathway. However, the molecular mechanisms of Cd-induced olfactory injury have not been characterized. In the present study, we investigated the role of the Nrf2-mediated antioxidant defense pathway in protecting against Cd-induced olfactory injury in zebrafish. A dose-dependent induction of Nrf2-regulated antioxidant genes associated with cellular responses to oxidativemore » stress was observed in the olfactory system of adult zebrafish following 24 h Cd exposure. Zebrafish larvae exposed to Cd for 3 h showed increased glutathione S-transferase pi (gst pi), glutamate–cysteine ligase catalytic subunit (gclc), heme oxygenase 1 (hmox1) and peroxiredoxin 1 (prdx1) mRNA levels indicative of Nrf2 activation, and which were blocked by morpholino-mediated Nrf2 knockdown. The inhibition of antioxidant gene induction in Cd-exposed Nrf2 morphants was associated with disruption of olfactory driven behaviors, increased cell death and loss of olfactory sensory neurons (OSNs). Nrf2 morphants also exhibited a downregulation of OSN-specific genes after Cd exposure. Pre-incubation of embryos with sulforaphane (SFN) partially protected against Cd-induced olfactory tissue damage. Collectively, our results indicate that oxidative stress is an important mechanism of Cd-mediated injury in the zebrafish olfactory system. Moreover, the Nrf2 pathway plays a protective role against cellular oxidative damage and is important in maintaining zebrafish olfactory function. -- Highlights: ► Oxidative stress is an important mechanism of Cd-mediated olfactory injury. ► Cd induces antioxidant gene expression in the zebrafish olfactory system.

  6. Nrf2 target genes are induced under marginal selenium-deficiency

    PubMed Central

    Müller, Mike; Banning, Antje; Brigelius-Flohé, Regina

    2010-01-01

    A suboptimal selenium supply appears to prevail in Europe. The current study, therefore, was focused on the changes in gene expression under a suboptimal selenium intake. Previous microarray analyses in the colon of mice fed either a selenium-adequate or a moderately deficient diet revealed a change in genes of several pathways. Severe selenium-deficiency has been found previously to influence Nrf2-regulated genes of the adaptive response. Since the previous pathway analyses were done with a program not searching for Nrf2 target genes, respective genes were manually selected and confirmed by qPCR. qPCR revealed an induction of phase II (Nqo1, Gsts, Sult1b1 and Ugt1a6) and antioxidant enzymes (Hmox1, Mt2, Prdx1, Srxn1, Sod1 and Gclc) under the selenium-poor diet, which is considered to compensate for the loss of selenoproteins. The strongest effects were observed in the duodenum where preferentially genes for antioxidant enzymes were up-regulated. These also include the mRNA of the selenoproteins TrxR1 and GPx2 that would enable their immediate translation upon selenium refeeding. The down-regulation of Gsk3β in moderate selenium-deficiency observed in the previous paper provides a possible explanation for the activation of the Nrf2 pathway, because inhibition of GSK3β results in the nuclear accumulation of Nrf2. PMID:21189866

  7. Withaferin A induces heme oxygenase (HO-1) expression in endothelial cells via activation of the Keap1/Nrf2 pathway.

    PubMed

    Heyninck, Karen; Sabbe, Linde; Chirumamilla, Chandra Sekhar; Szarc Vel Szic, Katarzyna; Vander Veken, Pieter; Lemmens, Kristien J A; Lahtela-Kakkonen, Maija; Naulaerts, Stefan; Op de Beeck, Ken; Laukens, Kris; Van Camp, Guy; Weseler, Antje R; Bast, Aalt; Haenen, Guido R M M; Haegeman, Guy; Vanden Berghe, Wim

    2016-06-01

    Withaferin A (WA), a natural phytochemical derived from the plant Withania somnifera, is a well-studied bioactive compound exerting a broad spectrum of health promoting effects. To gain better insight in the potential therapeutic capacity of WA, we evaluated the transcriptional effects of WA on primary human umbilical vein endothelial cells (HUVECs) and an endothelial cell line (EA.hy926). RNA microarray analysis of WA treated HUVEC cells demonstrated increased expression of the antioxidant gene heme oxygenase (HO-1). Transcriptional regulation of this gene is strongly dependent on the transcription factor NF-E2-related factor 2 (Nrf2), which senses chemical changes in the cell and coordinates transcriptional responses to maintain chemical homeostasis via expression of antioxidant genes and cytoprotective Phase II detoxifying enzymes. Under normal conditions, Nrf2 is kept in the cytoplasm by Kelch-like ECH-associated protein 1 (Keap1), an adaptor protein controlling the half-life of Nrf2 via constant proteasomal degradation. In this study we demonstrate that WA time- and concentration-dependently induces HO-1 expression in endothelial cells via upregulation and increased nuclear translocation of Nrf2. According to the crucial negative regulatory role of Keap1 in Nrf2 expression levels, a direct interaction of WA with Keap1 could be demonstrated. In vitro and in silico evaluations suggest that specific cysteine residues in Keap1 might be involved in the interaction with WA. Copyright © 2016 Elsevier Inc. All rights reserved.

  8. The role of COX-2 and Nrf2/ARE in anti-inflammation and antioxidative stress: Aging and anti-aging.

    PubMed

    Luo, Cheng; Urgard, Egon; Vooder, Tõnu; Metspalu, Andres

    2011-08-01

    Oxidative stress and inflammation are constant features of many chronic diseases and complications, and have been linked to carcinogenesis. Cyclooxygenase 2 (COX-2), a rate-limiting enzyme for the synthesis of prostaglandins, plays important roles in physiology and pathology, but has been a source of controversy within the scientific and clinical community. However, recent work has shown that nuclear factor erythroid-2-related factor-2 (Nrf2) confers protection against oxidative stress. Furthermore, COX-2-dependent electrophile oxo-derivative (EFOX) molecules have been shown to act as anti-inflammatory mediators via activation of the Nrf2-dependent antioxidant response element (ARE). These studies have provided more insight into COX-2-mediated events. The function of all tissues, especially epithelial and endothelial tissues, declines with age, leading to the production of reactive oxygen species (ROS). COX-2 expression increases with aging in most tissues, due in part to ROS, chemical reactions, physical shearing, and dietary molecules. Here we discuss new findings related to COX-2 inflammatory and anti-inflammatory responses. Taken together, we hypothesize that COX-2 levels increase during the aging process because increasing levels of ROSs necessitate the involvement of COX-2-dependent EFOXs for anti-inflammation and Nrf2/ARE signaling for antioxidation. We also propose that COX-2 may act as an intrinsic biological aging clock due to its role in balancing inflammatory and anti-inflammatory responses. Copyright © 2011 Elsevier Ltd. All rights reserved.

  9. Nrf2 protects human bladder urothelial cells from arsenite and monomethylarsonous acid toxicity

    DOE Office of Scientific and Technical Information (OSTI.GOV)

    Wang Xiaojun; Sun Zheng; Chen Weimin

    2007-12-01

    Arsenic is widely spread in our living environment and imposes a big challenge on human health worldwide. Arsenic damages biological systems through multiple mechanisms including the generation of reactive oxygen species. The transcription factor Nrf2 regulates the cellular antioxidant response that protects cells from various insults. In this study, the protective role of Nrf2 in arsenic toxicity was investigated in a human bladder urothelial cell line, UROtsa. Using a UROtsa cell line stably infected with Nrf2-siRNA, we clearly demonstrate that compromised Nrf2 expression sensitized the cells to As(III)- and MMA(III)-induced toxicity. On the other hand, the activation of the Nrf2more » pathway by tert-butylhydroquinone (tBHQ) and sulforaphane (SF), the known Nrf2-inducers, rendered UROtsa cells more resistant to As(III) and MMA(III). Furthermore, the wild-type mouse embryo fibroblast (WT-MEF) cells were protected from As(III)- and MMA(III)-induced toxicity following Nrf2 activation by tBHQ or SF, whereas neither tBHQ nor SF conferred protection in the Nrf2{sup -/-}MEF cells, demonstrating that tBHQ- or SF-mediated protection against As(III)- and MMA(III)-induced toxicity depends on Nrf2 activation. These results, obtained by both loss of function and gain of function analyses, clearly demonstrate the protective role of Nrf2 in arsenic-induced toxicity. The current work lays the groundwork for using Nrf2 activators for therapeutic and dietary interventions against adverse effects of arsenic.« less

  10. Nuclear factor erythroid-2-related factor regulates LRWD1 expression and cellular adaptation to oxidative stress in human embryonal carcinoma cells.

    PubMed

    Hung, Jui-Hsiang; Wee, Shi-Kae; Omar, Hany A; Su, Chia-Hui; Chen, Hsing-Yi; Chen, Pin-Shern; Chiu, Chien-Chih; Wu, Ming-Syuan; Teng, Yen-Ni

    2018-05-01

    Leucine-rich repeats and WD repeat domain-containing protein 1 (LRWD1) is implicated in the regulation of signal transduction, transcription, RNA processing and tumor development. However, LRWD1 transcriptional regulation is not fully understood. This study aimed to investigate the relationship between LRWD1 expression and reactive oxygen species (ROS) level in human embryonal carcinoma cell line, NT2/D1 cells, which will help in understanding the transcriptional regulatory role of ROS in cells. Results showed that the exposure of NT2/D1 cells to various concentrations of hydrogen peroxide (H 2 O 2 ) and the nitric oxide (NO) donor sodium nitroprusside (SNP) caused a significant increase in the mRNA and protein expression of LRWD1. In addition, LRWD1 promoter luciferase reporter assay, and Chromatin Immunoprecipitation assay (CHIP assay) showed that nuclear factor erythroid-2-related factor (Nrf2) was involved in the regulation of LRWD1 expression in response to oxidative stress. The involvement of Nrf2 was confirmed by shRNA-mediated knockdown of Nrf2 in NT2/D1 cells, which caused a significant decrease in LRWD1 expression in response to oxidative stress. Similarly, LRWD1 knockdown resulted in the accumulation of H 2 O 2 and superoxide anion radical (O2-). Blocking ROS production by N-acetyl cysteine (NAC) protected NT2/D1 shLRWD1cells from H 2 O 2 -induced cell death. Collectively, oxidative stress increased LRWD1 expression through a Nrf2-dependent mechanism, which plays an important role in cellular adaptation to oxidative stress. These results highlight an evidence, on the molecular level, about LRWD1 transcriptional regulation under oxidative stress. Copyright © 2018 Elsevier B.V. and Société Française de Biochimie et Biologie Moléculaire (SFBBM). All rights reserved.

  11. Amomum tsao-ko suppresses lipopolysaccharide-induced inflammatory responses in RAW264.7 macrophages via Nrf2-dependent heme oxygenase-1 expression.

    PubMed

    Li, Bin; Choi, Hee-Jin; Lee, Dong-Sung; Oh, Hyuncheol; Kim, Youn-Chul; Moon, Jin-Young; Park, Won-Hwan; Park, Sun-Dong; Kim, Jai-Eun

    2014-01-01

    Amomum tsao-ko Crevost et Lemaire, used as a spice in Asia, is an important source of Chinese cuisine and traditional Chinese medicines. A. tsao-ko is reported to exert a variety of biological and pharmacological activities, including anti-proliferative, anti-oxidative and neuroprotective effects. In this study, NNMBS227, consisting of the ethanol extract of A. tsao-ko, exhibited potent anti-inflammatory activities in RAW264.7 macrophages. We investigated the effect of NNMBS227 in the suppression of pro-inflammatory mediators, including pro-inflammatory enzymes (inducible nitric oxide synthase and cyclooxygenase-2) and cytokines (tumor necrosis factor-α and interleukin-1β) in LPS stimulated macrophages. NNMBS227 also inhibited the phosphorylation and degradation of IκB-α, as well as the nuclear translocation of nuclear factor kappa B (NF-κB) p65 caused by stimulation with LPS. In addition, NNMBS227 induced heme oxygenase (HO)-1 expression through the nuclear translocation of nuclear factor E2-related factor 2 (Nrf2) in macrophages. Using tin protoporphyrin (SnPP), an HO activity inhibitor, we confirmed an association between the anti-inflammatory effects of NNMBS227 and the up-regulation of HO-1. These findings suggest that Nrf2-dependent increases in the expression of HO-1 induced by NNMBS227 conferred anti-inflammatory activities in LPS stimulated RAW264.7 macrophages.

  12. CDDO-Im protects from acetaminophen hepatotoxicity through induction of Nrf2-dependent genes

    DOE Office of Scientific and Technical Information (OSTI.GOV)

    Reisman, Scott A.; Buckley, David B.; Tanaka, Yuji

    CDDO-Im is a synthetic triterpenoid recently shown to induce cytoprotective genes through the Nrf2-Keap1 pathway, an important mechanism for the induction of cytoprotective genes in response to oxidative stress. Upon oxidative or electrophilic insult, the transcription factor Nrf2 translocates to the nucleus, heterodimerizes with small Maf proteins, and binds to antioxidant response elements (AREs) in the upstream promoter regions of various cytoprotective genes. To further elucidate the hepatoprotective effects of CDDO-Im, wild-type and Nrf2-null mice were pretreated with CDDO-Im (1 mg/kg, i.p.) or vehicle (DMSO), and then administered acetaminophen (500 mg/kg, i.p.). Pretreatment of wild-type mice with CDDO-Im reduced livermore » injury caused by acetaminophen. In contrast, hepatoprotection by CDDO-Im was not observed in Nrf2-null mice. CDDO-Im increased Nrf2 protein expression and Nrf2-ARE binding in wild-type, but not Nrf2-null mice. Furthermore, CDDO-Im increased the mRNA expression of the Nrf2 target genes NAD(P)H: quinone oxidoreductase-1 (Nqo1); glutamate-cysteine ligase, catalytic subunit (Gclc); and heme-oxygenase-1 (Ho-1), in both a dose- and time-dependent manner. Conversely, CDDO-Im did not induce Nqo1, Gclc, and Ho-1 mRNA expression in Nrf2-null mice. Collectively, the present study shows that CDDO-Im pretreatment induces Nrf2-dependent cytoprotective genes and protects the liver from acetaminophen-induced hepatic injury.« less

  13. 5-Hydroxy-3,6,7,8,3'4'-hexamethoxyflavone inhibits nitric oxide production in lipopolysaccharide-stimulated BV2 microglia via NF-κB suppression and Nrf-2-dependent heme oxygenase-1 induction.

    PubMed

    Kang, Chang-Hee; Kim, Min Jeong; Seo, Min Jeong; Choi, Yung Hyun; Jo, Wol Soon; Lee, Kyung-Tae; Jeong, Yong Kee; Kim, Gi-Young

    2013-07-01

    In this study, we found that 5-hydroxy-3,6,7,8,3'4'-hexamethoxyflavone (5HHMF) from Hizikia fusiforme considerably inhibits lipopolysaccharide (LPS)-stimulated NO production by suppressing the expression of inducible NO synthase (iNOS) in BV2 microglia. In addition, 5HHMF blocked LPS-induced phosphorylation of IκB, resulting in suppression of the nuclear translocation of nuclear factor-κB (NF-κB) subunits, namely p65 and p50, which are important molecules involved in the regulation of iNOS expression. Pyrrolidine dithiocarbamate (PDTC), a specific NF-κB inhibitor, along with 20S proteasome inhibitor (PSI) significantly inhibited LPS-induced iNOS expression, which indirectly suggested that 5HHMF downregulated iNOS expression by suppressing NF-κB activity. Thus, we found that 5HHMF enhances heme oxygenase-1 (HO-1) expression via nuclear factor-erythroid 2-related factor 2 (Nrf2) activation. In addition, cobalt protoporphyrin (CoPP), a specific HO-1 inducer, predominantly suppressed LPS-induced NO production. In contrast, zinc protoporphyrin (ZnPP), a specific HO-1 inhibitor, showed a partial suppressive effect of 5HHMF on LPS-induced NO production. Further, 5HHMF increased specific DNA-binding activity of Nrf2, and transient knockdown with Nrf2 siRNA subsequently reversed 5HHMF-induced NO inhibition, which was followed by suppression of HO-1 activity. Taken together, our findings indicate that 5HHMF suppresses NO production through modulation of iNOS, consequently suppressing NF-κB activity and induction of Nrf2-dependent HO-1 activity. Copyright © 2013 Elsevier Ltd. All rights reserved.

  14. Curcumin by down-regulating NF-kB and elevating Nrf2, reduces brain edema and neurological dysfunction after cerebral I/R.

    PubMed

    Li, Wei; Suwanwela, Nijasri C; Patumraj, Suthiluk

    2016-07-01

    Oxidation, inflammation, and apoptosis are three critical factors for the pathogenic mechanism of cerebral ischemia/reperfusion (I/R) injury. Curcumin exhibits substantial biological properties via anti-oxidation, anti-inflammation and anti-apoptotic effects; however, the molecular mechanism underlying the effects of curcumin against cerebral I/R injury remains unclear. To investigate the effects of curcumin on cerebral I/R injury associated with water content, infarction volume, and the expression of nuclear factor-kappa-B (NF-κB) and nuclear factor-erythroid-related factor-2 (Nrf2). Middle cerebral artery occlusion (MCAO, 1-hour occlusion and 24-hour reperfusion) was performed in male Wistar rats (n=64) as a cerebral I/R injury model. In the MCAO+CUR group, the rats were administered curcumin (300mg/kg BW, i.p.) at 30min after occlusion. The same surgical procedures were performed in SHAM rats without MCAO occlusion. At 24h post-operation, the parameters, including neurological deficit scores, blood brain barrier (BBB) disruption, water content, and infarction volume, were determined. Brain tissue NF-κB and Nrf2 expression levels were assayed through immunohistochemistry. Compared with the SHAM group, BBB disruption, neurological deficit, and increased brain water content and infarction volume were markedly demonstrated in the MCAO group. NF-κB expression was enhanced in the MCAO group. However, in the MCAO+CUR group, the upregulation of Nrf2, an anti-oxidation related protein, was consistent with a significant decline in the water content, infarction volume, and NF-κB expression. The protective effects of curcumin against cerebral I/R injury reflect anti-oxidation, anti-inflammation and anti-apoptotic activities, resulting in the elevation of Nrf2 and down-regulation of NF-κB. Copyright © 2015 Elsevier Inc. All rights reserved.

  15. Airborne nitro-PAHs induce Nrf2/ARE defense system against oxidative stress and promote inflammatory process by activating PI3K/Akt pathway in A549 cells.

    PubMed

    Shang, Yu; Zhou, Qian; Wang, Tiantian; Jiang, Yuting; Zhong, Yufang; Qian, Guangren; Zhu, Tong; Qiu, Xinghua; An, Jing

    2017-10-01

    Ambient particulate matter (PM) is a worldwide health issue of concern. However, limited information is available regarding the toxic contributions of the nitro-derivatives of polycyclic aromatic hydrocarbons (nitro-PAHs). This study intend to examine whether 1-nitropyrene (1-NP) and 3-nitrofluoranthene (3-NF) could activate the nuclear factor-erythroid 2-related factor 2/antioxidant response element (Nrf2/ARE) antioxidant defense system, and whether the phosphatidylinositol 3-kinase/protein kinase B (PI3K/Akt) pathway participates in regulating pro-inflammatory responses in A549 cells. Firstly, 1-NP and 3-NF concentration-dependently induced cellular apoptosis, reactive oxygen species (ROS) generation, DNA damage, S phase cell cycle arrest and differential expression of related cytokine genes. Secondly, 1-NP and 3-NF activated the Nrf2/ARE defense system, as evidenced by increased protein expression levels and nuclear translocation of transcription factor Nrf2, elevated Nrf2/ARE binding activity, up-regulated expression of the target gene heme oxygenase-1 (HO-1). Significantly increased protein expression of DNA-dependent protein kinase catalytic subunit (DNA-PKcs) and phosphorylation level of Akt indicated that the PI3K/Akt pathway was activated during pro-inflammatory process. Further, both PI3K inhibitor (LY294002) and Akt inhibitor (MK-2206) reversed the elevated TNF-α expression to control level. Our results suggested that Nrf2/ARE pathway activation might cause an initiation step in cellular protection against oxidative stress caused by nitro-PAHs, and the PI3K/Akt pathway participated in regulating inflammatory responses. Copyright © 2017 Elsevier Ltd. All rights reserved.

  16. Sulforaphane protects rodent retinas against ischemia-reperfusion injury through the activation of the Nrf2/HO-1 antioxidant pathway.

    PubMed

    Pan, Hong; He, Meihua; Liu, Ruixing; Brecha, Nicholas C; Yu, Albert Cheung Hoi; Pu, Mingliang

    2014-01-01

    Retinal ischemia-reperfusion (I/R) injury induces oxidative stress, leukocyte infiltration, and neuronal cell death. Sulforaphane (SF), which can be obtained in cruciferous vegetables such as broccoli, exerts protective effects in response to oxidative stress in various tissues. These effects can be initiated through nuclear factor E2-related factor 2 (Nrf2)-mediated induction of heme oxygenase-1 (HO-1). This investigation was designed to elucidate the neural protective mechanisms of SF in the retinal I/R rat model. Animals were intraperitoneally (i.p.) injected with SF (12.5 mg/kg) or vehicle (corn oil) once a day for 7 consecutive days. Then, retinal I/R was made by elevating the intraocular pressure (IOP) to 130 mmHg for 1 h. To determine if HO-1 was involved in the Nrf2 antioxidant pathway, rats were subjected to protoporphyrin IX zinc (II) (ZnPP, 30 mg/kg, i.p.) treatments at 24 h before retinal ischemia. The neuroprotective effects of SF were assessed by determining the morphology of the retina, counting the infiltrating inflammatory cells and the surviving retinal ganglion cells (RGCs) and amacrine cells, and measuring apoptosis in the retinal layers. The expression of Nrf2 and HO-1 was studied by immunofluorescence analysis and western blotting. I/R induced a marked increase of ROS generation, caused pronounced inflammation, increased the apoptosis of RGCs and amacrine cells and caused the thinning of the inner retinal layer (IRL), and these effects were diminished or abolished by SF pretreatment. Meanwhile, SF pretreatment significantly elevated the nuclear accumulation of Nrf2 and the level of HO-1 expression in the I/R retinas; however, ZnPP reversed the protective effects of SF on I/R retinas. Together, we offer direct evidence that SF had protective effects on I/R retinas, which could be attributed, at least in part, to the activation of the Nrf2/HO-1 antioxidant pathway.

  17. Sulforaphane Protects Rodent Retinas against Ischemia-Reperfusion Injury through the Activation of the Nrf2/HO-1 Antioxidant Pathway

    PubMed Central

    Liu, Ruixing; Brecha, Nicholas C.; Yu, Albert Cheung Hoi; Pu, Mingliang

    2014-01-01

    Retinal ischemia-reperfusion (I/R) injury induces oxidative stress, leukocyte infiltration, and neuronal cell death. Sulforaphane (SF), which can be obtained in cruciferous vegetables such as broccoli, exerts protective effects in response to oxidative stress in various tissues. These effects can be initiated through nuclear factor E2-related factor 2 (Nrf2)-mediated induction of heme oxygenase-1 (HO-1). This investigation was designed to elucidate the neural protective mechanisms of SF in the retinal I/R rat model. Animals were intraperitoneally (i.p.) injected with SF (12.5 mg/kg) or vehicle (corn oil) once a day for 7 consecutive days. Then, retinal I/R was made by elevating the intraocular pressure (IOP) to 130 mmHg for 1 h. To determine if HO-1 was involved in the Nrf2 antioxidant pathway, rats were subjected to protoporphyrin IX zinc (II) (ZnPP, 30 mg/kg, i.p.) treatments at 24 h before retinal ischemia. The neuroprotective effects of SF were assessed by determining the morphology of the retina, counting the infiltrating inflammatory cells and the surviving retinal ganglion cells (RGCs) and amacrine cells, and measuring apoptosis in the retinal layers. The expression of Nrf2 and HO-1 was studied by immunofluorescence analysis and western blotting. I/R induced a marked increase of ROS generation, caused pronounced inflammation, increased the apoptosis of RGCs and amacrine cells and caused the thinning of the inner retinal layer (IRL), and these effects were diminished or abolished by SF pretreatment. Meanwhile, SF pretreatment significantly elevated the nuclear accumulation of Nrf2 and the level of HO-1 expression in the I/R retinas; however, ZnPP reversed the protective effects of SF on I/R retinas. Together, we offer direct evidence that SF had protective effects on I/R retinas, which could be attributed, at least in part, to the activation of the Nrf2/HO-1 antioxidant pathway. PMID:25470382

  18. Apocynin protects against neurological damage induced by quinolinic acid by an increase in glutathione synthesis and Nrf2 levels.

    PubMed

    Cruz-Álvarez, Silvia; Santana-Martínez, Ricardo; Avila-Chávez, Euclides; Barrera-Oviedo, Diana; Hernández-Pando, Rogelio; Pedraza-Chaverri, José; Maldonado, Perla D

    2017-05-14

    Apocynin (APO) is a well-known NADPH oxidase (NOX) inhibitor. However, several studies have reported its ability to increase glutathione (GSH) levels. Due to GSH is a major non-enzymatic antioxidant in brain, the aim of this study was to evaluate, in the striatum of control and quinolinic acid (QUIN) injected rats, the effect of APO administration on: (1) GSH levels, (2) activity of some enzymes involved in the GSH metabolism, and (3) nuclear factor erythroid-2-related factor 2 (Nrf2) mRNA levels. Animals received QUIN 240nmol in right striatum and APO (5mg/kg, i.p.), 30min before and 60min after intrastriatal injection. APO treatment prevented the QUIN-induced histological damage to the striatum. In control rats, APO treatment increased GSH and Nrf2 mRNA levels and the activities of gamma-glutamylcysteine ligase (γ-GCL), glutathione-S-transferase (GST) and glutathione peroxidase (GPx). On the other hand, APO treatment prevented the QUIN-induced decrease in GSH and Nrf2 levels, and in γ-GCL and GPx activities. These data indicate that APO is able to increase GSH levels and the activity of proteins involved in its metabolism, which could be associated with its ability to increase the Nrf2 mRNA levels. Copyright © 2017 IBRO. Published by Elsevier Ltd. All rights reserved.

  19. Protective Effect of Decursin Extracted from Angelica gigas in Male Infertility via Nrf2/HO-1 Signaling Pathway

    PubMed Central

    Bae, Woong Jin; Ha, U. Syn; Choi, Jin Bong; Kim, Kang Sup; Kim, Su Jin; Cho, Hyuk Jin; Hong, Sung Hoo; Lee, Ji Youl; Wang, Zhiping; Hwang, Sung Yeoun; Kim, Sae Woong

    2016-01-01

    Higher testicular temperature results in altered spermatogenesis due to heat-related oxidative stress. We examined the effects of decursin extracted from Angelica gigas Nakai on antioxidant activity in vitro and in a cryptorchidism-induced infertility rat model. TM3 Leydig cell viability was measured based on oxidative stress according to treatment. Either distilled water or AG 400 mg/kg of A. gigas extract was administered orally for 4 weeks after unilateral cryptorchidism was induced. After 1, 2, and 4 weeks, six rats from the control group and six rats from treatment group were sacrificed. Testicular weight, semen quality, antioxidant activities, nuclear factor erythroid 2-related factor 2 (Nrf2) protein, and mRNA expression of Nrf2-regulated genes were analyzed. Treatment with A. gigas extract (1) protected TM3 cells against oxidative stress in a dose-dependent manner, (2) improved the mean weight of the cryptorchid testis, (3) maintained sperm counts, motility, and spermatogenic cell density, (4) decreased levels of 8-hydroxy-2-deoxyguanosine (8-OHdG) and increased levels of superoxide dismutase (SOD), (5) significantly increased Nrf2 and heme oxygenase-1 (HO-1), and (6) significantly decreased apoptosis. This study suggests that decursin extracted from A. gigas is a supplemental agent that can reduce oxidative stress by Nrf2-mediated upregulation of HO-1 in rat experimentally induced unilateral cryptorchidism and may improve cryptorchidism-induced infertility. PMID:27034737

  20. Activation of Nrf2 by cadmium and its role in protection against cadmium-induced apoptosis in rat kidney cells

    DOE Office of Scientific and Technical Information (OSTI.GOV)

    Chen Jun; Shaikh, Zahir A., E-mail: ZShaikh@uri.ed

    Kidney is the primary target organ in chronic cadmium (Cd) toxicity, and oxidative stress plays an important role in this process. The nuclear transcription factor Nrf2 binds to antioxidant response elements (AREs) and regulates genes involved in protecting cells from oxidative damage. Whether kidney cells respond to Cd by activating Nrf2 is unknown. This study was designed to examine the Cd-induced activation of Nrf2 transcriptional activity in a stable rat kidney cell line, NRK-52E, and to investigate the protection this might offer against apoptosis. The cells were treated with 5-20 muM CdCl{sub 2} for 5 h, followed by a recoverymore » period of up to 24 h. A concentration-dependent increase (up to 2.9-fold) in the level of reactive oxygen species was noted upon termination of 5-h Cd treatment. The Nrf2-ARE binding activity also increased and peaked (6.1-fold) at 10 muM Cd concentration. Time-course study revealed that the binding activity increased at 1 h of Cd treatment and peaked 2 h post Cd treatment. Apoptosis was detected 6 h post treatment with Cd and a concentration- and time-dependent increase in the apoptotic cell population occurred during the next 18 h. Over-expression of Nrf2 by transient transfection conferred resistance against Cd-induced apoptosis. Conversely, suppression of Nrf2 expression by specific siRNA resulted in greater sensitivity of the cells to Cd by decreasing the levels of two antioxidant enzymes, hemeoxygenase-1 and glutamate-cysteine ligase. Taken together, these results suggest that in kidney cells the activation of Nrf2 is an adaptive intracellular response to Cd-induced oxidative stress, and that Nrf2 is protective against Cd-induced apoptosis.« less

  1. Loss of Nrf2 promotes alveolar type 2 cell loss in irradiated, fibrotic lung.

    PubMed

    Traver, Geri; Mont, Stacey; Gius, David; Lawson, William E; Ding, George X; Sekhar, Konjeti R; Freeman, Michael L

    2017-11-01

    The development of radiation-induced pulmonary fibrosis represents a critical clinical issue limiting delivery of therapeutic doses of radiation to non-small cell lung cancer. Identification of the cell types whose injury initiates a fibrotic response and the underlying biological factors that govern that response are needed for developing strategies that prevent or mitigate fibrosis. C57BL/6 mice (wild type, Nrf2 null, Nrf2 flox/flox , and Nrf2 Δ/Δ ; SPC-Cre) were administered a thoracic dose of 12Gy and allowed to recover for 250 days. Whole slide digital and confocal microscopy imaging of H&E, Masson's trichrome and immunostaining were used to assess tissue remodeling, collagen deposition and cell renewal/mobilization during the regenerative process. Histological assessment of irradiated, fibrotic wild type lung revealed significant loss of alveolar type 2 cells 250 days after irradiation. Type 2 cell loss and the corresponding development of fibrosis were enhanced in the Nrf2 null mouse. Yet, conditional deletion of Nrf2 in alveolar type 2 cells in irradiated lung did not impair type 2 cell survival nor yield an increased fibrotic phenotype. Instead, radiation-induced ΔNp63 stem/progenitor cell mobilization was inhibited in the Nrf2 null mouse while the propensity for radiation-induced myofibroblasts derived from alveolar type 2 cells was magnified. In summary, these results indicate that Nrf2 is an important regulator of irradiated lung's capacity to maintain alveolar type 2 cells, whose injury can initiate a fibrotic phenotype. Loss of Nrf2 inhibits ΔNp63 stem/progenitor mobilization, a key event for reconstitution of injured lung, while promoting a myofibroblast phenotype that is central for fibrosis. Copyright © 2017 Elsevier Inc. All rights reserved.

  2. Nuclear respiratory factor-1 and bioenergetics in tamoxifen-resistant breast cancer cells

    DOE Office of Scientific and Technical Information (OSTI.GOV)

    Radde, Brandie N.; Ivanova, Margarita M.; Mai, Huy Xuan

    Acquired tamoxifen (TAM) resistance is a significant clinical problem in treating patients with estrogen receptor α (ERα)+ breast cancer. We reported that ERα increases nuclear respiratory factor-1 (NRF-1), which regulates nuclear-encoded mitochondrial gene transcription, in MCF-7 breast cancer cells and NRF-1 knockdown stimulates apoptosis. Whether NRF-1 and target gene expression is altered in endocrine resistant breast cancer cells is unknown. We measured NRF-1and metabolic features in a cell model of progressive TAM-resistance. NRF-1 and its target mitochondrial transcription factor A (TFAM) were higher in TAM-resistant LCC2 and LCC9 cells than TAM-sensitive MCF-7 cells. Using extracellular flux assays we observed thatmore » LCC1, LCC2, and LCC9 cells showed similar oxygen consumption rate (OCR), but lower mitochondrial reserve capacity which was correlated with lower Succinate Dehydrogenase Complex, Subunit B in LCC1 and LCC2 cells. Complex III activity was lower in LCC9 than MCF-7 cells. LCC1, LCC2, and LCC9 cells had higher basal extracellular acidification (ECAR), indicating higher aerobic glycolysis, relative to MCF-7 cells. Mitochondrial bioenergetic responses to estradiol and 4-hydroxytamoxifen were reduced in the endocrine-resistant cells compared to MCF-7 cells. These results suggest the acquisition of altered metabolic phenotypes in response to long term antiestrogen treatment may increase vulnerability to metabolic stress. - Highlights: • NRF-1 and TFAM expression are higher in endocrine-resistant breast cancer cells. • Oxygen consumption rate is similar in endocrine-sensitive and resistant cells. • Mitochondrial reserve capacity is lower in endocrine-resistant cells. • Endocrine-resistant breast cancer cells have increased glycolysis. • Bioenergetic responses to E2 and tamoxifen are lower in endocrine-resistant cells.« less

  3. Lack of Association between Nuclear Factor Erythroid-Derived 2-Like 2 Promoter Gene Polymorphisms and Oxidative Stress Biomarkers in Amyotrophic Lateral Sclerosis Patients

    PubMed Central

    Chico, Lucia; Borgia, Loredana; Rocchi, Anna; D'Amelio, Antonia; Carlesi, Cecilia; Mancuso, Michelangelo; Siciliano, Gabriele

    2014-01-01

    Oxidative stress involvement has been strongly hypothesized among the possible pathogenic mechanisms of motor neuron degeneration in amyotrophic lateral sclerosis (ALS). The intracellular redox balance is finely modulated by numerous complex mechanisms critical for cellular functions, among which the nuclear factor erythroid-derived 2-like 2 (NFE2L2/Nrf2) pathways. We genotyped, in a cohort of ALS patients (n = 145) and healthy controls (n = 168), three SNPs in Nrf2 gene promoter: −653 A/G, −651 G/A, and −617 C/A and evaluated, in a subset (n = 73) of patients, advanced oxidation protein products (AOPP), iron-reducing ability of plasma (FRAP), and plasma thiols (-SH) as oxidative damage peripheral biomarkers. Nrf2 polymorphisms were not different among patients and controls. Increased levels of AOPP (P < 0.05) and decreased levels of FRAP (P < 0.001) have been observed in ALS patients compared with controls, but no difference in -SH values was found. Furthermore, no association was found between biochemical markers of redox balance and Nrf2 polymorphisms. These data confirm an altered redox balance in ALS and indicate that, while being abnormally modified compared to controls, the oxidative stress biomarkers assessed in this study are independent from the −653 A/G, −651 G/A, and −617 C/A Nrf2 SNPs in ALS patients. PMID:24672634

  4. Docosahexaenoic Acid (DHA) Provides Neuroprotection in Traumatic Brain Injury Models via Activating Nrf2-ARE Signaling.

    PubMed

    Zhu, Wei; Ding, Yuexia; Kong, Wei; Li, Tuo; Chen, Hongguang

    2018-04-16

    In this study, we explored the neuroprotective effects of docosahexaenoic acid (DHA) in traumatic brain injury (TBI) models. In this study, we first confirmed that DHA was neuroprotective against TBI via the NSS test and Morris water maze experiment. Western blot was conducted to identify the expression of Bax, caspase-3, and Bcl-2. And the cell apoptosis of the TBI models was validated by TUNEL staining. Relationships between nuclear factor erythroid 2-related factor 2-antioxidant response element (Nrf2-ARE) pathway-related genes and DHA were explored by RT-PCR and Western blot. Rats of the DHA group performed remarkably better than those of the TBI group in both NSS test and water maze experiment. DHA conspicuously promoted the expression of Bcl-2 and diminished that of cleaved caspase-3 and Bax, indicating the anti-apoptotic role of DHA. Superoxide dismutase (SOD) activity and cortical malondialdehyde content, glutathione peroxidase (GPx) activity were renovated in rats receiving DHA treatment, implying that the neuroprotective influence of DHA was derived from lightening the oxidative stress caused by TBI. Moreover, immunofluorescence and Western blot experiments revealed that DHA facilitated the translocation of Nrf2 to the nucleus. DHA administration also notably increased the expression of the downstream factors NAD(P)H:quinone oxidoreductase (NQO-1) and heme oxygenase 1(HO-1). DHA exerted neuroprotective influence on the TBI models, potentially through activating the Nrf2- ARE pathway.

  5. Adipose-derived mesenchymal stem cells promote the survival of fat grafts via crosstalk between the Nrf2 and TLR4 pathways

    PubMed Central

    Chen, Xiaosong; Yan, Liu; Guo, Zhihui; Chen, Zhaohong; Chen, Ying; Li, Ming; Huang, Chushan; Zhang, Xiaoping; Chen, Liangwan

    2016-01-01

    Autologous fat grafting is an effective reconstructive surgery technique; however, its success is limited by inconsistent graft retention and an environment characterized by high oxidative stress and inflammation. Adipose-derived stem cells (ADSCs) increase the survival of fat grafts, although the underlying mechanisms remain unclear. Here, TLR4−/− and Nrf2−/− mice were used to explore the effects of oxidative stress and inflammation on the viability and function of ADSCs in vitro and in vivo. Enrichment of fat grafts with ADSCs inhibited inflammatory cytokine production, enhanced growth factor levels, increased fat graft survival, downregulated NADPH oxidase (NOX)1 and 4 expression, increased vascularization and reduced ROS production in a manner dependent on toll-like receptor (TLR)-4 and nuclear factor erythroid 2-related factor 2 (Nrf2) expression. Immunohistochemical analysis showed that exposure to hypoxia enhanced ADSC growth and promoted the differentiation of ADSCs into vascular endothelial cells. Hypoxia-induced inflammatory cytokine, growth factor and NOX1/4 upregulation, as well as increased ROS production and apoptosis in ADSCs were dependent on TLR4 and Nrf2, which also modulated the effect of ADSCs on promoting endothelial progenitor cell migration and angiogenesis. Western blot analyses showed that the effects of hypoxia on ADSCs were regulated by crosstalk between Nrf2 antioxidant responses and NF-κB- and TLR4-mediated inflammatory responses. Taken together, our results indicate that ADSCs can increase the survival of fat transplants through the modulation of inflammatory and oxidative responses via Nrf2 and TLR4, suggesting potential strategies to improve the use of ADSCs for cell therapy. PMID:27607584

  6. Adipose-specific ablation of Nrf2 transiently delayed high-fat diet-induced obesity by altering glucose, lipid and energy metabolism of male mice.

    PubMed

    Zhang, Le; Dasuri, Kalavathi; Fernandez-Kim, Sun-Ok; Bruce-Keller, Annadora J; Keller, Jeffrey N

    2016-01-01

    Nuclear factor E2-related factor 2 (NRF2) is a well-known master controller of the cellular adaptive antioxidant and detoxification response. Recent studies demonstrated altered glucose, lipid and energy metabolism in mice with a global Nrf2 knockout. In the present study, we aim to determine the effects of an adipose-specific ablation of Nrf2 (ASAN) on diet-induced obesity (DIO) in male mice. The 6-week-old adipose-specific Nrf2 knockout (NK) and its Nrf2 control (NC) mice were fed with either control diet (CD) or high-fat diet (HFD) for 14 weeks. NK mice exhibited transiently delayed body weight (BW) growth from week 5 to week 11 of HFD feeding, higher daily physical activity levels and preferential use of fat over carbohydrates as a source of energy at week 8 of the CD-feeding period. After 14 weeks of feeding, NK mice showed comparable results with NC mice with respect to the overall BW and body fat content, but exhibited reduced blood glucose, reduced number but increased size of adipocytes, accompanied with elevated expression of many genes and proteins in the visceral fat related to glucose, lipid and energy metabolism (e.g. Fgf21 , Pgc1a ). These results indicated that NRF2 is an important mediator for glucose, lipid and energy metabolism in adipose tissue, and ASAN could have beneficial effect for prevention of DIO during the early development of mice.

  7. Modulatory effect of silymarin on nuclear factor-erythroid-2-related factor 2 regulated redox status, nuclear factor-κB mediated inflammation and apoptosis in experimental gastric ulcer.

    PubMed

    Arafa Keshk, Walaa; Zahran, Samer Mahmoud; Katary, Mohamed Alaa; Abd-Elaziz Ali, Darin

    2017-08-01

    Non-steroidal anti-inflammatory drugs (NSAIDs) consumption has been commonly associated with gastric mucosal lesions including gastric ulcer. Silymarin (SM) is a flavonoid mixture with anti-oxidant and anti-inflammatory activities which explain its protective role against hepatic and renal injuries. However, its impact on gastric ulcer has not yet been elucidated. Thus we went further to investigate the potential protective effects of SM against indomethacin-induced gastric injury in rats. Pretreatment with SM (50 mg/kg orally) attenuated the severity of gastric mucosal damage as evidenced by decreasing ulcer index (UI) and ulcer score, improvement of disturbed histopathologicl features to be insignificant with those induced by the reference anti-ulcer drug. Pretreatment with SM also suppressed gastric inflammation by decreasing myeloperoxidase activity, tumer necrosis factor-α (TNF- α) and interleukin 6 (IL6) levels along with nuclear factor kappa B p65 (NF-κB) expression. Meanwhile, SM prevent gastric oxidative stress via inhibition of lipid peroxides formation, enhancement of glutathione peroxidase, superoxide dismutase activities and up-regulation of nuclear factor-erythroid-2-related factor 2 (Nrf2), the redox-sensitive master regulator of oxidative stress signaling. In conclusion, the results herein revealed that SM has a gastro-protective effect which is mediated via suppression of gastric inflammation, oxidative stress, increased the anti-oxidant and the cyto-protective defense mechanisms. Copyright © 2017 Elsevier B.V. All rights reserved.

  8. Sulforaphane Inhibits Lipopolysaccharide-Induced Inflammation, Cytotoxicity, Oxidative Stress, and miR-155 Expression and Switches to Mox Phenotype through Activating Extracellular Signal-Regulated Kinase 1/2Nuclear Factor Erythroid 2-Related Factor 2/Antioxidant Response Element Pathway in Murine Microglial Cells

    PubMed Central

    Eren, Erden; Tufekci, Kemal Ugur; Isci, Kamer Burak; Tastan, Bora; Genc, Kursad; Genc, Sermin

    2018-01-01

    Sulforaphane (SFN) is a natural product with cytoprotective, anti-inflammatory, and antioxidant effects. In this study, we evaluated the mechanisms of its effects on lipopolysaccharide (LPS)-induced cell death, inflammation, oxidative stress, and polarization in murine microglia. We found that SFN protects N9 microglial cells upon LPS-induced cell death and suppresses LPS-induced levels of secreted pro-inflammatory cytokines, tumor necrosis factor-alpha, interleukin-1 beta, and interleukin-6. SFN is also a potent inducer of redox sensitive transcription factor, nuclear factor erythroid 2-related factor 2 (Nrf2), which is responsible for the transcription of antioxidant, cytoprotective, and anti-inflammatory genes. SFN induced translocation of Nrf2 to the nucleus via extracellular signal-regulated kinase 1/2 (ERK1/2) pathway activation. siRNA-mediated knockdown study showed that the effects of SFN on LPS-induced reactive oxygen species, reactive nitrogen species, and pro-inflammatory cytokine production and cell death are partly Nrf2 dependent. Mox phenotype is a novel microglial phenotype that has roles in oxidative stress responses. Our results suggested that SFN induced the Mox phenotype in murine microglia through Nrf2 pathway. SFN also alleviated LPS-induced expression of inflammatory microRNA, miR-155. Finally, SFN inhibits microglia-mediated neurotoxicity as demonstrated by conditioned medium and co-culture experiments. In conclusion, SFN exerts protective effects on microglia and modulates the microglial activation state. PMID:29410668

  9. Sesquiterpene Lactone Composition and Cellular Nrf2 Induction of Taraxacum officinale Leaves and Roots and Taraxinic Acid β-d-Glucopyranosyl Ester.

    PubMed

    Esatbeyoglu, Tuba; Obermair, Betina; Dorn, Tabea; Siems, Karsten; Rimbach, Gerald; Birringer, Marc

    2017-01-01

    Taraxacum officinale, the common dandelion, is a plant of the Asteraceae family, which is used as a food and medical herb. Various secondary plant metabolites such as sesquiterpene lactones, triterpenoids, flavonoids, phenolic acids, coumarins, and steroids have been described to be present in T. officinale. Dandelion may exhibit various health benefits, including antioxidant, anti-inflammatory, and anticarcinogenic properties. We analyzed the leaves and roots of the common dandelion (T. officinale) using high-performance liquid chromatography/mass spectrometry to determine its sesquiterpene lactone composition. The main compound of the leaf extract taraxinic acid β-d-glucopyranosyl ester (1), a sesquiterpene lactone, was isolated and the structure elucidation was conducted by nuclear magnetic resonance spectrometry. The leaf extract and its main compound 1 activated the transcription factor nuclear factor erythroid 2-related factor 2 (Nrf2) in human hepatocytes more significantly than the root extract. Furthermore, the leaf extract induced the Nrf2 target gene heme oxygenase 1. Overall, present data suggest that compound 1 may be one of the active principles of T. officinale.

  10. Cervical Cancer Cell Line Secretome Highlights the Roles of Transforming Growth Factor-Beta-Induced Protein ig-h3, Peroxiredoxin-2, and NRF2 on Cervical Carcinogenesis.

    PubMed

    Kontostathi, Georgia; Zoidakis, Jerome; Makridakis, Manousos; Lygirou, Vasiliki; Mermelekas, George; Papadopoulos, Theofilos; Vougas, Konstantinos; Vlamis-Gardikas, Alexios; Drakakis, Peter; Loutradis, Dimitrios; Vlahou, Antonia; Anagnou, Nicholas P; Pappa, Kalliopi I

    2017-01-01

    Cancer cells acquire unique secretome compositions that contribute to tumor development and metastasis. The aim of our study was to elucidate the biological processes involved in cervical cancer, by performing a proteomic analysis of the secretome from the following informative cervical cell lines: SiHa (HPV16+), HeLa (HPV18+), C33A (HPV-), and HCK1T (normal). Proteins were analyzed by 2D gel electrophoresis coupled to MALDI-TOF-MS. Enrichment of secreted proteins with characteristic profiles for each cell line was followed by the identification of differentially expressed proteins. Particularly, transforming growth factor-beta-induced protein ig-h3 (Beta ig-h3) and peroxiredoxin-2 (PRDX2) overexpression in the secretome of cancer cell lines was detected and confirmed by Western blot. Bioinformatics analysis identified the transcription factor NRF2 as a regulator of differentially expressed proteins in the cervical cancer secretome. NRF2 levels were measured by both Western blot and Multiple Reaction Monitoring (MRM) in the total cell extract of the four cell lines. NRF2 was upregulated in SiHa and C33A compared to HCK1T. In conclusion, the secreted proteins identified in cervical cancer cell lines indicate that aberrant NRF2-mediated oxidative stress response (OSR) is a prominent feature of cervical carcinogenesis.

  11. Synergy between the KEAP1/NRF2 and PI3K Pathways Drives Non-Small-Cell Lung Cancer with an Altered Immune Microenvironment.

    PubMed

    Best, Sarah A; De Souza, David P; Kersbergen, Ariena; Policheni, Antonia N; Dayalan, Saravanan; Tull, Dedreia; Rathi, Vivek; Gray, Daniel H; Ritchie, Matthew E; McConville, Malcolm J; Sutherland, Kate D

    2018-04-03

    The lung presents a highly oxidative environment, which is tolerated through engagement of tightly controlled stress response pathways. A critical stress response mediator is the transcription factor nuclear factor erythroid-2-related factor 2 (NFE2L2/NRF2), which is negatively regulated by Kelch-like ECH-associated protein 1 (KEAP1). Alterations in the KEAP1/NRF2 pathway have been identified in 23% of lung adenocarcinomas, suggesting that deregulation of the pathway is a major cancer driver. We demonstrate that inactivation of Keap1 and Pten in the mouse lung promotes adenocarcinoma formation. Notably, metabolites identified in the plasma of Keap1 f/f /Pten f/f tumor-bearing mice indicate that tumorigenesis is associated with reprogramming of the pentose phosphate pathway. Furthermore, the immune milieu was dramatically changed by Keap1 and Pten deletion, and tumor regression was achieved utilizing immune checkpoint inhibition. Thus, our study highlights the ability to exploit both metabolic and immune characteristics in the detection and treatment of lung tumors harboring KEAP1/NRF2 pathway alterations. Copyright © 2018 Elsevier Inc. All rights reserved.

  12. Effects of monascin on anti-inflammation mediated by Nrf2 activation in advanced glycation end product-treated THP-1 monocytes and methylglyoxal-treated wistar rats.

    PubMed

    Lee, Bao-Hong; Hsu, Wei-Hsuan; Huang, Tao; Chang, Yu-Ying; Hsu, Ya-Wen; Pan, Tzu-Ming

    2013-02-13

    Hyperglycemia is associated with advanced glycation end products (AGEs). This study was designed to evaluate the inhibitory effects of monascin on receptor for advanced glycation end product (RAGE) signal and THP-1 monocyte inflammation after treatment with S100b, a specific ligand of RAGE. Monascin inhibited cytokine production by S100b-treated THP-1 monocytes via up-regulation of nuclear factor-erythroid 2-related factor-2 (Nrf2) and alleviated p47phox translocation to the membrane. Methylglyoxal (MG, 600 mg/kg bw) was used to induce diabetes in Wistar rats. Inhibitions of RAGE and p47phox by monascin were confirmed by peripheral blood mononuclear cells (PBMCs) of MG-induced rats. Silymarin (SM) was used as a positive control group. It was found that monascin promoted heme oxygenase-1 (HO-1) expression mediated by Nrf2. Suppressions of AGEs, tumor necrosis factor-α (TNF-α), and interleukin-1β (IL-β) in serum of MG-induced rats were attenuated in the monascin administration group treated with retinoic acid (RA). RA treatment resulted in Nrf2 inactivation by increasing RA receptor-α (RARα) activity, suggesting that RA acts as an inhibitor of Nrf2. The results showed that monascin exerted anti-inflammatory and antioxidative effects mediated by Nrf2 to prevent the development of diseases such as type 2 diabetes caused by inflammation.

  13. Bakuchiol Is a Phenolic Isoprenoid with Novel Enantiomer-selective Anti-influenza A Virus Activity Involving Nrf2 Activation*

    PubMed Central

    Shoji, Masaki; Arakaki, Yumie; Esumi, Tomoyuki; Kohnomi, Shuntaro; Yamamoto, Chihiro; Suzuki, Yutaka; Takahashi, Etsuhisa; Konishi, Shiro; Kido, Hiroshi; Kuzuhara, Takashi

    2015-01-01

    Influenza represents a substantial threat to human health and requires novel therapeutic approaches. Bakuchiol is a phenolic isoprenoid compound present in Babchi (Psoralea corylifolia L.) seeds. We examined the anti-influenza viral activity of synthetic bakuchiol using Madin-Darby canine kidney cells. We found that the naturally occurring form, (+)-(S)-bakuchiol, and its enantiomer, (−)-(R)-bakuchiol, inhibited influenza A viral infection and growth and reduced the expression of viral mRNAs and proteins in these cells. Furthermore, these compounds markedly reduced the mRNA expression of the host cell influenza A virus-induced immune response genes, interferon-β and myxovirus-resistant protein 1. Interestingly, (+)-(S)-bakuchiol had greater efficacy than (−)-(R)-bakuchiol, indicating that chirality influenced anti-influenza virus activity. In vitro studies indicated that bakuchiol did not strongly inhibit the activities of influenza surface proteins or the M2 ion channel, expressed in Chinese hamster ovary cells. Analysis of luciferase reporter assay data unexpectedly indicated that bakuchiol may induce some host cell factor(s) that inhibited firefly and Renilla luciferases. Next generation sequencing and KeyMolnet analysis of influenza A virus-infected and non-infected cells exposed to bakuchiol revealed activation of transcriptional regulation by nuclear factor erythroid 2-related factor (Nrf), and an Nrf2 reporter assay showed that (+)-(S)-bakuchiol activated Nrf2. Additionally, (+)-(S)-bakuchiol up-regulated the mRNA levels of two Nrf2-induced genes, NAD(P)H quinone oxidoreductase 1 and glutathione S-transferase A3. These findings demonstrated that bakuchiol had enantiomer-selective anti-influenza viral activity involving a novel effect on the host cell oxidative stress response. PMID:26446794

  14. Protective function of pyridoxamine on retinal photoreceptor cells via activation of the p‑Erk1/2/Nrf2/Trx/ASK1 signalling pathway in diabetic mice.

    PubMed

    Ren, Xiang; Sun, Hong; Zhang, Chenghong; Li, Chen; Wang, Jinlei; Shen, Jie; Yu, Dong; Kong, Li

    2016-07-01

    The present study aimed to investigate the mechanisms that mediate the protective effects of pyridoxamine (PM) on light‑damaged retinal photoreceptor cells in diabetic mice. A high‑fat diet and streptozotocin were used to induce a mouse model of type II diabetes. During the experiment, mice were divided the mice into three types of group, as follows: Control groups (negative control and light‑damaged groups); experimental groups (diabetic and diabetic light‑damaged groups); and treatment groups (25, 50 and 100 mg/kg PM‑treated groups). Using hematoxylin‑eosin staining, the number of nuclear layer cells were counted. Western blotting and immunohistochemistry were performed to measure the levels of thioredoxin (Trx), phospho‑extracellular signal‑regulated kinase 1/2 (p‑Erk1/2), nuclear factor erythroid 2‑related factor 2 (Nrf2) and apoptosis signal‑regulating kinase 1 (ASK1). The photoreceptor cell count in the outer nuclear layer of the light‑damaged, diabetic control and diabetic light‑damaged groups were significantly reduced compared with the negative control group (P<0.001). The cell counts in the PM‑treated groups were significantly increased compared with the diabetic group (P<0.001). Compared with the negative control group, the light‑damaged, diabetic and diabetic light‑damaged groups exhibited significantly decreased Trx, p‑Erk1/2 and Nrf2 expression levels (P<0.001), and significantly increased ASK1 expression levels (P<0.001). However, in the PM‑treated groups, Trx, p‑Erk1/2 and Nrf2 expression levels were significantly increased (P<0.001), and ASK1 expression was significantly decreased (P<0.001). The results of the present study demonstrate that PM protects retinal photoreceptor cells against light damage in diabetic mice, and that its mechanism may be associated with the upregulation of Trx, p‑Erk1/2 and Nrf2 expression, and the downregulation of ASK1 expression.

  15. Transport stress-induced cerebrum oxidative stress is not mitigated by activating the Nrf2 antioxidant defense response in newly hatched chicks.

    PubMed

    Ge, J; Li, H; Sun, F; Li, X-N; Lin, J; Xia, J; Zhang, C; Li, J-L

    2017-07-01

    Transportation of newly hatched chicks from the hatchery to the farm is inevitable, especially for parent stock and grandsire parent stock chicks. However, the possible effects of transport stress in the newly hatched chicks are poorly understood. The aim of this study was to determine the adaptive responses to transport stress by activing the nuclear factor-erythroid 2-related factor 2 (Nrf2)-induced antioxidant defense. One hundred twenty newly hatched chicks were divided into 3 groups (control group, transport group, and simulation transport group) for 2, 4, and 8 h of real or simulated transportation. Transport stress could cause oxidative stress in the cerebrum of newly hatched chicks by increasing lipid peroxidation and production of free radicals and decreasing the activities of antioxidant enzymes and the glutathione:oxidized glutathione ratio. Transport stress activated the Nrf2 signaling pathway and triggered the transcription of antioxidant parameters. However, transport stress-induced cerebrum oxidative stress was not mitigated by activating the Nrf2 antioxidant defense response in newly hatched chicks.

  16. L-Arginine ameliorates cardiac left ventricular oxidative stress by upregulating eNOS and Nrf2 target genes in alloxan-induced hyperglycemic rats.

    PubMed

    Ramprasath, Tharmarajan; Kumar, Palani Hamenth; Puhari, Shanavas Syed Mohamed; Murugan, Ponniah Senthil; Vasudevan, Varadaraj; Selvam, Govindan Sadasivam

    2012-11-23

    Hyperglycemia is independently related with excessive morbidity and mortality in cardiovascular disorders. L-Arginine-nitric oxide (NO) pathway and the involvement of NO in modulating nuclear factor-E2-related factor-2 (Nrf2) signaling were well established. In the present study we investigated, whether L-arginine supplementation would improve the myocardial antioxidant defense under hyperglycemia through activation of Nrf2 signaling. Diabetes was induced by alloxan monohydrate (90 mg kg(-1) body weight) in rats. Both non-diabetic and diabetic group of rats were divided into three subgroups and they were administered either with L-arginine (2.25%) or L-NAME (0.01%) in drinking water for 12 days. Results showed that L-arginine treatment reduced the metabolic disturbances in diabetic rats. Antioxidant enzymes and glutathione levels were found to be increased in heart left ventricles, thereby reduction of lipid peroxidation by L-arginine treatment. Heart histopathological analysis further validates the reversal of typical diabetic characteristics consisting of alterations in myofibers and myofibrillary degeneration. qRT-PCR studies revealed that L-arginine treatment upregulated the transcription of Akt and downregulated NF-κB. Notably, transcription of eNOS and Nrf2 target genes was also upregulated, which were accompanied by enhanced expression of Nrf2 in left ventricular tissue from diabetic and control rats. Under these findings, we suggest that targeting of eNOS and Nrf2 signaling by L-arginine supplementation could be used as a potential treatment method to alleviate the late diabetic complications. Copyright © 2012 Elsevier Inc. All rights reserved.

  17. Sulforaphane Attenuated the Pro-Inflammatory State Induced by Hydrogen Peroxide in SH-SY5Y Cells Through the Nrf2/HO-1 Signaling Pathway.

    PubMed

    de Oliveira, Marcos Roberto; Brasil, Flávia Bittencourt; Fürstenau, Cristina Ribas

    2018-02-23

    Sulforaphane (SFN), an isothiocyanate obtained from cruciferous vegetables, exerts antioxidant, antiapoptotic, and antitumor activities in different cell types. Moreover, SFN has been viewed as an anti-inflammatory agent. Nonetheless, the mechanism underlying the ability of SFN in modulating the immune response in mammalian cells is not completely understood yet. Therefore, we investigated here whether and how SFN would be effective in preventing inflammation induced by a pro-oxidant agent (hydrogen peroxide, H 2 O 2 ) in the human neuroblastoma SH-SY5Y cells. The cells were treated with SFN at 5 μM for 30 min before a challenge with H 2 O 2 for an additional 24 h. Pretreatment with SFN reduced the secretion of interleukin-1β (IL-1β) and tumor necrosis factor-α (TNF-α), as well as decreased the levels of cyclooxygenase-2 (COX-2) in H 2 O 2 -treated cells. SFN also decreased the activity of the transcription factor nuclear factor-κB (NF-κB) and the immunocontent of the p65 NF-κB subunit in the cell nucleus. The inhibition of heme oxygenase-1 (HO-1) by ZnPP-IX at 10 μM or the silencing of the nuclear factor erythroid 2-related factor 2 (Nrf2) transcription factor by small interfering RNA targeting Nrf2 attenuated the anti-inflammatory and cytoprotective effects induced by SFN. Therefore, SFN exerted an anti-inflammatory effect in H 2 O 2 -challenged SH-SY5Y cells by a mechanism dependent on the Nrf2/HO-1 signaling pathway.

  18. Effect of cellular ubiquitin levels on the regulation of oxidative stress response and proteasome function via Nrf1.

    PubMed

    Lee, Donghee; Ryu, Kwon-Yul

    2017-04-01

    The polyubiquitin genes Ubb and Ubc are upregulated under oxidative stress induced by arsenite [As(III)]. However, the role of ubiquitin (Ub) under As(III) exposure is not known in detail. In a previous study, we showed that the reduced viability observed in Ubc -/- mouse embryonic fibroblasts under As(III) exposure was not due to dysregulation of the Nrf2-Keap1 pathway, which prompted us to investigate another NFE2 family protein, nuclear factor erythroid 2-related factor 1 (Nrf1). In this study, we found that Ub deficiency due to Ubc knockdown in N2a cells reduced cell viability and proteasome activity under As(III) exposure. Furthermore, mRNA levels of the proteasome subunit Psma1 were also reduced. In addition, Ub deficiency led to the nuclear accumulation of the p65 isoform of Nrf1 under As(III) exposure. Interestingly, the overexpression of p65-Nrf1 recapitulated the phenotypes of Ub-deficient N2a cells under As(III) exposure. On the other hand, Nrf1 knockdown suppressed the death of Ub-deficient N2a cells upon exposure to As(III). Therefore, the levels of p65-Nrf1 may play an important role in the maintenance of cell viability under oxidative stress induced by As(III). Copyright © 2017 Elsevier Inc. All rights reserved.

  19. Omeprazole induces heme oxygenase-1 in fetal human pulmonary microvascular endothelial cells via hydrogen peroxide-independent Nrf2 signaling pathway

    DOE Office of Scientific and Technical Information (OSTI.GOV)

    Patel, Ananddeep; Zhang, Shaojie; Shrestha, Amrit

    Omeprazole (OM) is an aryl hydrocarbon receptor (AhR) agonist and a proton pump inhibitor that is used to treat humans with gastric acid related disorders. Recently, we showed that OM induces NAD (P) H quinone oxidoreductase-1 (NQO1) via nuclear factor erythroid 2-related factor 2 (Nrf2)-dependent mechanism. Heme oxygenase-1 (HO-1) is another cytoprotective and antioxidant enzyme that is regulated by Nrf2. Whether OM induces HO-1 in fetal human pulmonary microvascular endothelial cells (HPMEC) is unknown. Therefore, we tested the hypothesis that OM will induce HO-1 expression via Nrf2 in HPMEC. OM induced HO-1 mRNA and protein expression in a dose-dependent manner.more » siRNA-mediated knockdown of AhR failed to abrogate, whereas knockdown of Nrf2 abrogated HO-1 induction by OM. To identify the underlying molecular mechanisms, we determined the effects of OM on cellular hydrogen peroxide (H{sub 2}O{sub 2}) levels since oxidative stress mediated by the latter is known to activate Nrf2. Interestingly, the concentration at which OM induced HO-1 also increased H{sub 2}O{sub 2} levels. Furthermore, H{sub 2}O{sub 2} independently augmented HO-1 expression. Although N-acetyl cysteine (NAC) significantly decreased H{sub 2}O{sub 2} levels in OM-treated cells, we observed that OM further increased HO-1 mRNA and protein expression in NAC-pretreated compared to vehicle-pretreated cells, suggesting that OM induces HO-1 via H{sub 2}O{sub 2}-independent mechanisms. In conclusion, we provide evidence that OM transcriptionally induces HO-1 via AhR - and H{sub 2}O{sub 2} - independent, but Nrf2 - dependent mechanisms. These results have important implications for human disorders where Nrf2 and HO-1 play a beneficial role. - Highlights: • Omeprazole induces HO-1 in human fetal lung cells. • AhR deficiency fails to abrogate omeprazole-mediated induction of HO-1. • Nrf2 knockdown abrogates omeprazole-mediated HO-1 induction in human lung cells. • Hydrogen peroxide depletion

  20. Resveratrol protects primary rat hepatocytes against oxidative stress damage: activation of the Nrf2 transcription factor and augmented activities of antioxidant enzymes.

    PubMed

    Rubiolo, Juan Andrés; Mithieux, Gilles; Vega, Félix Victor

    2008-09-04

    Oxidative stress is recognized as an important factor in the development of liver pathologies. The reactive oxygen species endogenously generated or as a consequence of xenobiotic metabolism are eliminated by enzymatic and nonenzymatic cellular systems. Besides endogen defences, the antioxidant consumption in the diet has an important role in the protection against the development of diseases product of oxidative damage. Resveratrol is a naturally occurring compound which is part of the human diet. This molecule has been shown to have many biological properties, including antioxidant activity. We decided to test if resveratrol could protect primary hepatocytes in culture from oxidative stress damage and if so, to determine if this compound affects the cellular detoxifying systems and their regulation through the Nrf2 transcription factor that regulates the expression of antioxidant and phase II detoxifying enzymes. Cell death by necrosis was detected by measuring the activity of lactate dehydrogenase liberated to the medium. The activities of antioxidant and phase II enzymes were measured using previously described methods. Activation of the Nrf2 transcription factor was studied by confocal microscopy and the Nrf2 and its coding mRNA levels were determined by western blot and quantitative PCR respectively. Resveratrol pre-treatment effectively protected hepatocytes in culture exposed to oxidative stress, increasing the activities of catalase, superoxide dismutase, glutathione peroxidase, NADPH quinone oxidoreductase and glutathione-S-transferase. Resveratrol increases the level of Nrf2 and induces its translocation to the nucleus. Also, it increases the concentration of the coding mRNA for Nrf2. In this work we show that resveratrol could be a useful drug for the protection of liver cells from oxidative stress induced damage.

  1. Hydrogen sulfide (H2S) attenuates uranium-induced acute nephrotoxicity through oxidative stress and inflammatory response via Nrf2-NF-κB pathways.

    PubMed

    Zheng, Jifang; Zhao, Tingting; Yuan, Yan; Hu, Nan; Tang, Xiaoqing

    2015-12-05

    As an endogenous gaseous mediator, H2S exerts anti-oxidative, anti-inflammatory and cytoprotective effects in kidneys. This study was designed to investigate the protective effect of H2S against uranium-induced nephrotoxicity in adult SD male rats after in vivo effect of uranium on endogenous H2S formation was explored in kidneys. The levels of endogenous H2S and H2S-producing enzymes (CBS and CSE) were measured in renal homogenates from rats intoxicated by an intraperitoneally (i.p.) injection of uranyl acetate at a single dose of 2.5, 5 or 10 mg/kg. In rats injected i.p. with uranyl acetate (5 mg/kg) or NaHS (an H2S donor, 28 or 56 μmol/kg) alone or in combination, we determined biochemical parameters and histopathological alteration to assess kidney function, examined oxidative stress markers, and investigated Nrf2 and NF-κB pathways in kidney homogenates. The results suggest that uranium intoxication in rats decreased endogenous H2S generation as well as CBS and CSE protein expression. NaHS administration in uranium-intoxicated rats ameliorated the renal biochemical indices and histopathological effects, lowered MDA accumulation, and restored GSH level and anti-oxidative enzymes activities like SOD, CAT, GPx and GST. NaHS treatment in uranium-intoxicated rats activated uranium-inhibited protein expression and nuclear translocation of transcription factor Nrf2, which increased protein expression of downstream target-Nrf2 genes HO-1, NQO-1, GCLC, and TXNRD-1. NaHS administration in uranium-intoxicated rats inhibited uranium-induced nuclear translocation and phosphorylation of transcription factor κB/p65, which decreased protein expression of target-p65 inflammatory genes TNF-α, iNOS, and COX-2. Taken together, these data implicate that H2S can afford protection to rat kidneys against uranium-induced adverse effects through induction of antioxidant defense by activating Nrf2 pathway and reduction of inflammatory response by suppressing NF-κB pathway

  2. Protection by sulforaphane from type 1 diabetes-induced testicular apoptosis is associated with the up-regulation of Nrf2 expression and function.

    PubMed

    Jiang, Xin; Bai, Yang; Zhang, Zhiguo; Xin, Ying; Cai, Lu

    2014-09-01

    Diabetes-induced testicular apoptosis is predominantly due to increased oxidative stress. The nuclear factor-erythroid 2-related factor 2 (Nrf2), as a master transcription factor in controlling anti-oxidative systems, is able to be induced by sulforaphane (SFN). To examine whether SFN prevents testicular apoptosis, type 1 diabetic mouse model was induced with multiple low-dose streptozotocin. Diabetic and age-matched control mice were treated with and without SFN at 0.5mg/kg daily in five days of each week for 3months and then kept until 6months. Diabetes significantly increased testicular apoptosis that was associated with endoplasmic reticulum stress and mitochondrial cell death pathways, shown by the increased expression of C/EBP homologous protein (CHOP), cleaved caspase-12, Bax to Bcl2 expression ratio, and cleaved caspase-3. Diabetes also significantly increased testicular oxidative damage, inflammation and fibrosis, and decreased germ cell proliferation. All these diabetic effects were significantly prevented by SFN treatment for the first 3months, and the protective effect could be sustained at 3months after SFN treatment. SFN was able to up-regulate Nrf2 expression and function. The latter was reflected by the increased phosphorylation of Nrf2 at Ser40 and expression of Nrf2 downstream antioxidants at mRNA and protein levels. These results suggest that type 1 diabetes significantly induced testicular apoptosis and damage along with increasing oxidative stress and cell death and suppressing Nrf2 expression and function. SFN is able to prevent testicular oxidative damage and apoptosis in type 1 diabetes mice, which may be associated with the preservation of testicular Nrf2 expression and function under diabetic condition. Copyright © 2014 Elsevier Inc. All rights reserved.

  3. Edaravone protects the retina against ischemia/reperfusion‑induced oxidative injury through the PI3K/Akt/Nrf2 pathway.

    PubMed

    Xu, Yi-Pin; Han, Fang; Tan, Jian

    2017-12-01

    Retinal ischemia/reperfusion (I/R) injury can occur as a result of a number of ocular diseases or ischemic events in the brain, leading to possible vision loss if not treated properly. The overproduction of reactive oxygen species is important in the process of I/R injury. Edaravone, a free radical scavenger, has been demonstrated to have a neuroprotective effect in cerebral ischemia; however, its effect against retinal I/R injury remains to be fully elucidated. Therefore, the present study investigated the effects of edaravone on the oxidative parameters, retinal inflammation and apoptosis induced by I/R injury, and treated photoreceptor‑derived 661W cells with hydrogen peroxide (H2O2) and edaravone to examine the underlying mechanism. For the in vivo study, oxidative parameters (malondialdehyde, DNA fragmentation, total antioxidant status, superoxide dismutase and glutathione) in the retina, retinal thickness, and apoptotic index in the ganglionic cell layer and inner nuclear layer were measured. For the in vitro study, the effects of edaravone or nuclear factor erythroid‑2‑related factor 2 (Nrf2) small interfering RNA or phosphatidylinositol 3‑kinase (PI3K)/Akt inhibitors on cell viability, membrane integrity, levels of phosphorylated‑Akt, Akt and nuclear Nrf2 of H2O2‑treated 661W cells were examined. The results demonstrated that edaravone inhibited the oxidative injury in the retina induced by the retinal I/R procedure and increased retinal inflammation, and apoptosis. The results of the in vitro experiments demonstrated that edaravone effectively protected the viability and the membrane integrity of the H2O2‑treated 661W cells via the phosphatidylinositol 3‑kinase (PI3K)/Akt/Nrf2pathway. These results indicated the potential protective effect of edaravone against retinal I/R injury and provided a novel explanation for the protective effects of edaravone.

  4. Adaptive induction of NF-E2-related factor-2-driven antioxidant genes in endothelial cells in response to hyperglycemia.

    PubMed

    Ungvari, Zoltan; Bailey-Downs, Lora; Gautam, Tripti; Jimenez, Rosario; Losonczy, Gyorgy; Zhang, Cuihua; Ballabh, Praveen; Recchia, Fabio A; Wilkerson, Donald C; Sonntag, William E; Pearson, Kevin; de Cabo, Rafael; Csiszar, Anna

    2011-04-01

    Hyperglycemia in diabetes mellitus promotes oxidative stress in endothelial cells, which contributes to development of cardiovascular diseases. Nuclear factor erythroid 2-related factor-2 (Nrf2) is a transcription factor activated by oxidative stress that regulates expression of numerous reactive oxygen species (ROS) detoxifying and antioxidant genes. This study was designed to elucidate the homeostatic role of adaptive induction of Nrf2-driven free radical detoxification mechanisms in endothelial protection under diabetic conditions. Using a Nrf2/antioxidant response element (ARE)-driven luciferase reporter gene assay we found that in a cultured coronary arterial endothelial cell model hyperglycemia (10-30 mmol/l glucose) significantly increases transcriptional activity of Nrf2 and upregulates the expression of the Nrf2 target genes NQO1, GCLC, and HMOX1. These effects of high glucose were significantly attenuated by small interfering RNA (siRNA) downregulation of Nrf2 or overexpression of Keap-1, which inactivates Nrf2. High-glucose-induced upregulation of NQO1, GCLC, and HMOX1 was also prevented by pretreatment with polyethylene glycol (PEG)-catalase or N-acetylcysteine, whereas administration of H(2)O(2) mimicked the effect of high glucose. To test the effects of metabolic stress in vivo, Nrf2(+/+) and Nrf2(-/-) mice were fed a high-fat diet (HFD). HFD elicited significant increases in mRNA expression of Gclc and Hmox1 in aortas of Nrf2(+/+) mice, but not Nrf2(-/-) mice, compared with respective standard diet-fed control mice. Additionally, HFD-induced increases in vascular ROS levels were significantly greater in Nrf2(-/-) than Nrf2(+/+) mice. HFD-induced endothelial dysfunction was more severe in Nrf2(-/-) mice, as shown by the significantly diminished acetylcholine-induced relaxation of aorta of these animals compared with HFD-fed Nrf2(+/+) mice. Our results suggest that adaptive activation of the Nrf2/ARE pathway confers endothelial protection under

  5. Vitamin E antagonizes ozone-induced asthma exacerbation in Balb/c mice through the Nrf2 pathway.

    PubMed

    Duan, Liju; Li, Jinquan; Ma, Ping; Yang, Xu; Xu, Shunqing

    2017-09-01

    Millions of people are regularly exposed to ozone, a gas known to contribute significantly to worsening the symptoms of patients with asthma. However, the mechanisms underlying these ozone exacerbation effects are not fully understood. In this study, we examined the exacerbation effect of ozone in OVA-induced asthma mice and tried to demonstrate the protective mechanism of vitamin E (VE). An asthma mouse model was established, and used to identify the exacerbating effects of ozone by assessing cytokine and serum immunoglobulin concentrations, airway leukocyte infiltration, histopathological changes in lung tissues, and airway hyper-responsiveness. We then determined the amount of reactive oxygen species (ROS) accumulated, the extent to which VE induced ROS elimination, and examined the antagonistic effects of VE on the ozone-induced exacerbating effects. This study showed that 1-ppm ozone exposure could exacerbate OVA-induced asthma in mice. More importantly we found that ozone induced oxidative stress in asthmatic airways may lead to the inhibition of Nuclear factor-erythroid 2-related factor 2 (Nrf2), and may subsequently induce even more exaggerated oxidative stress associated with asthma exacerbation. Through VE induced Nrf2 activation and the subsequent increase in Nrf2 target protein expression, this study suggests a novel mechanism for alleviating ozone exacerbated asthma symptoms. Copyright © 2017 Elsevier Ltd. All rights reserved.

  6. Anti-neuroinflammatory Effect of Emodin in LPS-Stimulated Microglia: Involvement of AMPK/Nrf2 Activation.

    PubMed

    Park, Sun Young; Jin, Mei Ling; Ko, Min Jung; Park, Geuntae; Choi, Young-Whan

    2016-11-01

    AMPK/Nrf2 signaling regulates multiple antioxidative factors and exerts neuroprotective effects. Emodin is one of the main bioactive components extracted from Polygonum multiflorum, a plant possessing important activities for human health and for treating a variety of diseases. This study examined whether emodin can activate AMPK/Nrf2 signaling and induce the expression of genes targeted by this pathway. In addition, the anti-neuroinflammatory properties of emodin in lipopolysaccharide (LPS)-stimulated microglia were examined. In microglia, the emodin treatment increased the levels of LKB1, CaMKII, and AMPK phosphorylation. Emodin increased the translocation and transactivity of Nrf2 and enhanced the levels of HO-1 and NQO1. In addition, the emodin-mediated expression of HO-1 and NQO1 was attenuated completely by an AMPK inhibitor (compound C). Moreover, emodin decreased dramatically the LPS-induced production of NO and PGE 2 as well as the protein expression and promoter activity of inducible nitric oxide synthase (iNOS) and cyclooxygenase-2 (COX-2). In addition, emodin effectively inhibited the production of pro-inflammatory cytokines, TNF-α and IL-6, and reduced the level of IκBα phosphorylation, leading to the suppression of the nuclear translocation, phosphorylation, and transactivity of NF-κB. Emodin also suppressed the LPS-stimulated activation of STATs, JNK, and p38 MAPK. The anti-inflammatory effects of emodin were reversed by transfection with Nrf-2 and HO-1 siRNA and by a co-treatment with an AMPK inhibitor. These results suggest that emodin isolated from P. multiflorum can be used as a natural anti-neuroinflammatory agent that exerts its effects by inducing HO-1 and NQO1 via AMPK/Nrf2 signaling in microglia.

  7. Photoprotection by dietary phenolics against melanogenesis induced by UVA through Nrf2-dependent antioxidant responses

    PubMed Central

    Chaiprasongsuk, Anyamanee; Onkoksoong, Tasanee; Pluemsamran, Thanyawan; Limsaengurai, Saowalak; Panich, Uraiwan

    2015-01-01

    Dietary phenolics may play a protective role in UV-mediated skin pigmentation through their antioxidant and UV-absorbing actions. In this study, we investigated whether genetic silencing of Nrf2, regulating the transcription of antioxidant genes, affected melanogenesis in primary human epidermal melanocytes (HEMn) and B16F10 melanoma cells subjected to UVA (8 J/cm2) exposure. Then, we explored the antimelanogenic actions of phenolics; caffeic acid (CA) and ferulic acid (FA) providing partial UVA protection; quercetin (QU) and rutin (RU) providing strong UVA protection and; avobenzone (AV), an efficient UVA filter, in association with modulation of Nrf2-mediated antioxidant defenses in response to UVA insults in B16F10 cells. Upon oxidative insults, Nrf2 silencing promoted melanogenesis in both HEMn and B16F10 cells irradiated with UVA. Stimulation of melanogenesis by UVA correlated with increased ROS and oxidative DNA damage (8-OHdG), GSH depletion as well as a transient downregulation of Nrf2 nuclear translocation and of Nrf2-ARE signaling in B16F10 cells. All test compounds exerted antimelanogenic effects with respect to their abilities to reverse UVA-mediated oxidative damage as well as downregulation of Nrf2 activity and its target antioxidants (GCLC, GST and NQO1) in B16F10 cells. In conclusion, defective Nrf2 may promote melanogenesis under UVA irradiation through oxidative stress mechanisms. Compounds with antioxidant and/or UVA absorption properties could protect against UVA-induced melanogenesis through indirect regulatory effect on Nrf2-ARE pathway. PMID:26765101

  8. Arsenic-induced malignant transformation of human keratinocytes: Involvement of Nrf2

    PubMed Central

    Pi, Jingbo; Diwan, Bhalchandra A.; Sun, Yang; Liu, Jie; Qu, Wei; He, Yuying; Styblo, Miroslav; Waalkes, Michael P.

    2009-01-01

    Arsenic is a well-known human skin carcinogen but the underlying mechanisms of carcinogenesis are unclear. Transcription factor Nrf2-mediated antioxidant response represents a critical cellular defense mechanism, and emerging data suggest that constitutive activation of Nrf2 contributes to malignant phenotype. In the present study when an immortalized, non-tumorigenic human keratinocyte cell line (HaCaT) was continuously exposed to environmentally relevant level of inorganic arsenite (100 nM) for 28 weeks, malignant transformation occurred as evidenced by the formation of highly aggressive squamous cell carcinoma after inoculation into nude mice. To investigate the mechanisms involved, a broad array of biomarkers for transformation were assessed in these arsenic-transformed cells (termed As-TM). In addition to increased secretion of matrix metalloproteinase-9 (MMP-9), a set of markers for squamous differentiation and skin keratinization, including keratin-1, keratin-10, involucrin, and loricrin, were significantly elevated in As-TM cells. Furthermore, As-TM cells showed increased intracellular glutathione, elevated expression of Nrf2 and its target genes, as well as generalized apoptotic resistance. In contrast to increased basal Nrf2 activity in As-TM cells, a diminished Nrf2-mediated antioxidant response induced by acute exposure to high dose of arsenite or tert-butyl hydroxyquinone occurred. The findings that multiple biomarkers for malignant transformation observed in As-TM cells, including MMP-9 and cytokeratins, are potentially regulated by Nrf2 suggest constitutive Nrf2 activation may be involved in arsenic carcinogenesis of skin. The weakened Nrf2 activation in response to oxidative stressors observed in As-TM cells, coupled with acquired apoptotic resistance, would potentially have increased the likelihood of transmittable oxidative DNA damage and fixation of mutational/DNA damage events. PMID:18572023

  9. Paeonol extracted from Paeonia suffruticosa Andr. ameliorated UVB-induced skin photoaging via DLD/Nrf2/ARE and MAPK/AP-1 pathway.

    PubMed

    Sun, ZhengWang; Du, Juan; Hwang, Eunson; Yi, Tae-Hoo

    2018-05-10

    Paeonia suffruticosa Andr. (PS) has been used in traditional Chinese medicine for a long time. However, there are no studies that investigate the preventive effects of PS on ultraviolet B (UVB)-induced photoaging. In this study, paeonol (PA) was detected the main compound in PS root. In vitro, PS and PA significantly inhibited UVB-induced phosphorylation of mitogen-activated protein kinase and activator protein 1 in keratinocytes, which consequently led to degradation of procollagen type I. On the other hand, PS and PA increased NAD(P)H:quinone oxidoreductase 1 and heme oxygenase-1 expression, confirmed by greater nuclear accumulation of nuclear factor E2-releated factor 2 (Nrf2). Furthermore, this study proved that the endogenous antioxidant system Nrf2/antioxidant response element was regulated by dihydrolipoamide dehydrogenase, a tricarboxylic acid (TCA) cycle-associated protein whose level was decreased after UVB exposure. PS and PA promoted the production of dihydrolipoamide dehydrogenase, as well as the activation of Nrf2 and antioxidant response element, resulting in preventing procollagen type I ruined caused by UVB. In vivo, topical application of PS and PA attenuated UVB-induced matrix metalloproteinase-1 production and promoted procollagen type I in hairless mice. These results suggested PA a promising botanical in protecting skin from UVB-induced photoaging. Copyright © 2018 John Wiley & Sons, Ltd.

  10. Ginger Compound [6]-Shogaol and Its Cysteine-Conjugated Metabolite (M2) Activate Nrf2 in Colon Epithelial Cells in Vitro and in Vivo

    PubMed Central

    2015-01-01

    In this study, we identified Nrf2 as a molecular target of [6]-shogaol (6S), a bioactive compound isolated from ginger, in colon epithelial cells in vitro and in vivo. Following 6S treatment of HCT-116 cells, the intracellular GSH/GSSG ratio was initially diminished but was then elevated above the basal level. Intracellular reactive oxygen species (ROS) correlated inversely with the GSH/GSSG ratio. Further analysis using gene microarray showed that 6S upregulated the expression of Nrf2 target genes (AKR1B10, FTL, GGTLA4, and HMOX1) in HCT-116 cells. Western blotting confirmed upregulation, phosphorylation, and nuclear translocation of Nrf2 protein followed by Keap1 decrease and upregulation of Nrf2 target genes (AKR1B10, FTL, GGTLA4, HMOX1, and MT1) and glutathione synthesis genes (GCLC and GCLM). Pretreatment of cells with a specific inhibitor of p38 (SB202190), PI3K (LY294002), or MEK1 (PD098059) attenuated these effects of 6S. Using ultra-high-performance liquid chromatography–tandem mass spectrometry, we found that 6S modified multiple cysteine residues of Keap1 protein. In vivo 6S treatment induced Nrf2 nuclear translocation and significantly upregulated the expression of MT1, HMOX1, and GCLC in the colon of wild-type mice but not Nrf2–/– mice. Similar to 6S, a cysteine-conjugated metabolite of 6S (M2), which was previously found to be a carrier of 6S in vitro and in vivo, also activated Nrf2. Our data demonstrated that 6S and its cysteine-conjugated metabolite M2 activate Nrf2 in colon epithelial cells in vitro and in vivo through Keap1-dependent and -independent mechanisms. PMID:25148906

  11. Ginger compound [6]-shogaol and its cysteine-conjugated metabolite (M2) activate Nrf2 in colon epithelial cells in vitro and in vivo.

    PubMed

    Chen, Huadong; Fu, Junsheng; Chen, Hao; Hu, Yuhui; Soroka, Dominique N; Prigge, Justin R; Schmidt, Edward E; Yan, Feng; Major, Michael B; Chen, Xiaoxin; Sang, Shengmin

    2014-09-15

    In this study, we identified Nrf2 as a molecular target of [6]-shogaol (6S), a bioactive compound isolated from ginger, in colon epithelial cells in vitro and in vivo. Following 6S treatment of HCT-116 cells, the intracellular GSH/GSSG ratio was initially diminished but was then elevated above the basal level. Intracellular reactive oxygen species (ROS) correlated inversely with the GSH/GSSG ratio. Further analysis using gene microarray showed that 6S upregulated the expression of Nrf2 target genes (AKR1B10, FTL, GGTLA4, and HMOX1) in HCT-116 cells. Western blotting confirmed upregulation, phosphorylation, and nuclear translocation of Nrf2 protein followed by Keap1 decrease and upregulation of Nrf2 target genes (AKR1B10, FTL, GGTLA4, HMOX1, and MT1) and glutathione synthesis genes (GCLC and GCLM). Pretreatment of cells with a specific inhibitor of p38 (SB202190), PI3K (LY294002), or MEK1 (PD098059) attenuated these effects of 6S. Using ultra-high-performance liquid chromatography-tandem mass spectrometry, we found that 6S modified multiple cysteine residues of Keap1 protein. In vivo 6S treatment induced Nrf2 nuclear translocation and significantly upregulated the expression of MT1, HMOX1, and GCLC in the colon of wild-type mice but not Nrf2(-/-) mice. Similar to 6S, a cysteine-conjugated metabolite of 6S (M2), which was previously found to be a carrier of 6S in vitro and in vivo, also activated Nrf2. Our data demonstrated that 6S and its cysteine-conjugated metabolite M2 activate Nrf2 in colon epithelial cells in vitro and in vivo through Keap1-dependent and -independent mechanisms.

  12. Protection by sulforaphane from type 1 diabetes-induced testicular apoptosis is associated with the up-regulation of Nrf2 expression and function

    DOE Office of Scientific and Technical Information (OSTI.GOV)

    Jiang, Xin; Bai, Yang; Zhang, Zhiguo

    Diabetes-induced testicular apoptosis is predominantly due to increased oxidative stress. The nuclear factor-erythroid 2-related factor 2 (Nrf2), as a master transcription factor in controlling anti-oxidative systems, is able to be induced by sulforaphane (SFN). To examine whether SFN prevents testicular apoptosis, type 1 diabetic mouse model was induced with multiple low-dose streptozotocin. Diabetic and age-matched control mice were treated with and without SFN at 0.5 mg/kg daily in five days of each week for 3 months and then kept until 6 months. Diabetes significantly increased testicular apoptosis that was associated with endoplasmic reticulum stress and mitochondrial cell death pathways, shownmore » by the increased expression of C/EBP homologous protein (CHOP), cleaved caspase-12, Bax to Bcl2 expression ratio, and cleaved caspase-3. Diabetes also significantly increased testicular oxidative damage, inflammation and fibrosis, and decreased germ cell proliferation. All these diabetic effects were significantly prevented by SFN treatment for the first 3 months, and the protective effect could be sustained at 3 months after SFN treatment. SFN was able to up-regulate Nrf2 expression and function. The latter was reflected by the increased phosphorylation of Nrf2 at Ser40 and expression of Nrf2 downstream antioxidants at mRNA and protein levels. These results suggest that type 1 diabetes significantly induced testicular apoptosis and damage along with increasing oxidative stress and cell death and suppressing Nrf2 expression and function. SFN is able to prevent testicular oxidative damage and apoptosis in type 1 diabetes mice, which may be associated with the preservation of testicular Nrf2 expression and function under diabetic condition. - Highlights: • Sulforaphane (SFN) could attenuate diabetes-induced germ cell apoptosis. • SFN could preserve germ cell proliferation under diabetic conditions. • SFN testicular protection was sustained until 3 months

  13. Stabilization of endogenous Nrf2 by minocycline protects against Nlrp3-inflammasome induced diabetic nephropathy.

    PubMed

    Shahzad, Khurrum; Bock, Fabian; Al-Dabet, Moh'd Mohanad; Gadi, Ihsan; Nazir, Sumra; Wang, Hongjie; Kohli, Shrey; Ranjan, Satish; Mertens, Peter R; Nawroth, Peter P; Isermann, Berend

    2016-10-10

    While a plethora of studies support a therapeutic benefit of Nrf2 activation and ROS inhibition in diabetic nephropathy (dNP), the Nrf2 activator bardoxolone failed in clinical studies in type 2 diabetic patients due to cardiovascular side effects. Hence, alternative approaches to target Nrf2 are required. Intriguingly, the tetracycline antibiotic minocycline, which has been in clinical use for decades, has been shown to convey anti-inflammatory effects in diabetic patients and nephroprotection in rodent models of dNP. However, the mechanism underlying the nephroprotection remains unknown. Here we show that minocycline protects against dNP in mouse models of type 1 and type 2 diabetes, while caspase -3,-6,-7,-8 and -10 inhibition is insufficient, indicating a function of minocycline independent of apoptosis inhibition. Minocycline stabilizes endogenous Nrf2 in kidneys of db/db mice, thus dampening ROS-induced inflammasome activation in the kidney. Indeed, minocycline exerts antioxidant effects in vitro and in vivo, reducing glomerular markers of oxidative stress. Minocycline reduces ubiquitination of the redox-sensitive transcription factor Nrf2 and increases its protein levels. Accordingly, minocycline mediated Nlrp3 inflammasome inhibition and amelioration of dNP are abolished in diabetic Nrf2 -/- mice. Taken together, we uncover a new function of minocycline, which stabilizes the redox-sensitive transcription factor Nrf2, thus protecting from dNP.

  14. Possible roles of the transcription factor Nrf1 (NFE2L1) in neural homeostasis by regulating the gene expression of deubiquitinating enzymes.

    PubMed

    Taniguchi, Hiroaki; Okamuro, Shota; Koji, Misaki; Waku, Tsuyoshi; Kubo, Kaori; Hatanaka, Atsushi; Sun, Yimeng; Chowdhury, A M Masudul Azad; Fukamizu, Akiyoshi; Kobayashi, Akira

    2017-02-26

    The transcription factor Nrf1 (NFE2L1) maintains protein homeostasis (proteostasis) by regulating the gene expression of proteasome subunits in response to proteasome inhibition. The deletion of the Nrf1 gene in neural stem/progenitor cells causes severe neurodegeneration due to the accumulation of ubiquitinated proteins in Purkinje cells and motor neurons (Nrf1 NKO mice). However, the molecular mechanisms governing this neurodegenerative process remain unclear. We demonstrate herein that the loss of Nrf1 leads to the reduced gene expression of the deubiquitinating enzymes (DUBs) but not proteasome subunits in Nrf1 NKO mice between P7 and P18. First, we show that K48-linked polyubiquitinated proteins accumulate in Nrf1-deficient Purkinje cells and cerebral cortex neurons. Nevertheless, loss of Nrf1 does not alter the expression and proteolytic activity of proteasome. A significantly reduced expression of deubiquitinating enzymes was also demonstrated in Nrf1-deficient cerebellar tissue using microarray analysis. The genome database further reveals species-conserved ARE, a Nrf1 recognition element, in the regulatory region of certain DUB genes. Furthermore, we show that Nrf1 can activate Usp9x gene expression related to neurodegeneration. Altogether these findings suggest that neurodegeneration in Nrf1 NKO mice may stem from the dysfunction of the ubiquitin-mediated regulation of neuronal proteins. Copyright © 2017 Elsevier Inc. All rights reserved.

  15. Protective Effects of Maillard Reaction Products of Whey Protein Concentrate against Oxidative Stress through an Nrf2-Dependent Pathway in HepG2 Cells.

    PubMed

    Pyo, Min Cheol; Yang, Sung-Yong; Chun, Su-Hyun; Oh, Nam Su; Lee, Kwang-Won

    2016-09-01

    Whey protein concentrate (WPC), which contains α-lactalbumin and β-lactoglobulin, is utilized widely in the food industry. The Maillard reaction is a complex reaction that produces Maillard reaction products (MRPs), which are associated with the formation of antioxidant compounds. In this study, the hepatoprotection activity of MRPs of WPC against oxidative stress through the nuclear factor-E2-related factor 2 (Nrf2)-dependent antioxidant pathway in HepG2 cells was examined. Glucose-whey protein concentrate conjugate (Glc-WPC) was obtained from Maillard reaction between WPC and glucose. The fluorescence intensity of Glc-WPC increased after 7 d compared to native WPC, and resulted in loss of 48% of the free amino groups of WPC. The sodium dodecyl sulfate-polyacrylamide gel electrophoresis (SDS-PAGE) patterns of Glc-WPC showed the presence of a high-molecular-weight portion. Treatment of HepG2 cells with Glc-WPC increased cell viability in the presence of oxidative stress, inhibited the generation of intracellular reactive oxygen species by tert-butyl hydroperoxide (t-BHP), and increased the glutathione level. Nrf2 translocation and Nrf2, reduced nicotinamide adenine dinucleotide phosphate (NAD(P)H)-quinone oxidoreductase 1 (NOQ1), heme oxygenase-1 (HO-1), glutamate-L-cysteine ligase (GCL)M and GCLC mRNA levels were increased by Glc-WPC. Also, Glc-WPC increased the phosphorylation of extracellular signal-regulated kinase (ERK) 1/2 and c-Jun N-terminal kinase (JNK). The results of this study demonstrate that Glc-WPC activates the Nrf2-dependent pathway through the phosphorylation of ERK1/2 and JNK in HepG2 cells, and induces production of antioxidant enzymes and phase II enzymes.

  16. Protective effect of ganodermanondiol isolated from the Lingzhi mushroom against tert-butyl hydroperoxide-induced hepatotoxicity through Nrf2-mediated antioxidant enzymes.

    PubMed

    Li, Bin; Lee, Dong-Sung; Kang, Yue; Yao, Nai-Qi; An, Ren-Bo; Kim, Youn-Chul

    2013-03-01

    Ganodermanondiol, a biologically active compound, was isolated from the Lingzhi mushroom (Ganoderma lucidum). The present study examined the protective effects of ganodermanondiol against tert-butyl hydroperoxide (t-BHP)-induced hepatotoxicity. Ganodermanondiol protected human liver-derived HepG2 cells through nuclear factor-E2-related factor 2 (Nrf2) pathway-dependent heme oxygenase-1 expressions. Moreover, ganodermanondiol increased cellular glutathione levels and the expression of the glutamine-cysteine ligase gene in a dose-dependent manner. Furthermore, ganodermanondiol exposure enhanced the phosphorylation of adenosine monophosphate-activated protein kinase (AMPK) and its upstream kinase activators, LKB1 and Ca(2+)/calmodulin-dependent protein kinase-II (CaMKII). This study indicates that ganodermanondiol exhibits potent cytoprotective effects on t-BHP-induced hepatotoxicity in human liver-derived HepG2 cells, presumably through Nrf2-mediated antioxidant enzymes and AMPK. Copyright © 2012 Elsevier Ltd. All rights reserved.

  17. Protective Effect of Thymoquinone against Cyclophosphamide-Induced Hemorrhagic Cystitis through Inhibiting DNA Damage and Upregulation of Nrf2 Expression.

    PubMed

    Gore, Prashant R; Prajapati, Chaitali P; Mahajan, Umesh B; Goyal, Sameer N; Belemkar, Sateesh; Ojha, Shreesh; Patil, Chandragouda R

    2016-01-01

    Cyclophosphamide (CYP) induced hemorrhagic cystitis is a dose-limiting side effect involving increased oxidative stress, inflammatory cytokines and suppressed activity of nuclear factor related erythroid 2-related factor (Nrf2). Thymoquinone (TQ), an active constituent of Nigella sativa seeds, is reported to increase the expression of Nrf2, exert antioxidant action, and anti-inflammatory effects in the experimental animals. The present study was designed to explore the effects of TQ on CYP-induced hemorrhagic cystitis in Balb/c mice. Cystitis was induced by a single intraperitoneal injection of CYP (200 mg/kg). TQ was administered intraperitoneally at 5, 10 and 20 mg/kg doses twice a day, for three days before and three days after the CYP administration. The efficacy of TQ was determined in terms of the protection against the CYP-induced histological perturbations in the bladder tissue, reduction in the oxidative stress, and inhibition of the DNA fragmentation. Immunohistochemistry was performed to examine the expression of Nrf2. TQ protected against CYP-induced oxidative stress was evident from significant reduction in the lipid peroxidation, restoration of the levels of reduced glutathione, catalase and superoxide dismutase activities. TQ treatment significantly reduced the DNA damage evident as reduced DNA fragmentation. A significant decrease in the cellular infiltration, edema, epithelial denudation and hemorrhage were observed in the histological observations. There was restoration and rise in the Nrf2 expression in the bladder tissues of mice treated with TQ. These results confirm that, TQ ameliorates the CYP-induced hemorrhagic cystitis in mice through reduction in the oxidative stress, inhibition of the DNA damage and through increased expression of Nrf2 in the bladder tissues.

  18. Inhibition of liver fibrosis by solubilized coenzyme Q10: Role of Nrf2 activation in inhibiting transforming growth factor-beta1 expression

    DOE Office of Scientific and Technical Information (OSTI.GOV)

    Choi, Hoo-Kyun; Pokharel, Yuba Raj; Lim, Sung Chul

    2009-11-01

    Coenzyme Q10 (CoQ10), an endogenous antioxidant, is important in oxidative phosphorylation in mitochondria. It has anti-diabetic and anti-cardiovascular disease effects, but its ability to protect against liver fibrosis has not been studied. Here, we assessed the ability of solubilized CoQ10 to improve dimethylnitrosamine (DMN)-induced liver fibrogenesis in mice. DMN treatments for 3 weeks produced a marked liver fibrosis as assessed by histopathological examination and tissue 4-hydroxyproline content. Solubilized CoQ10 (10 and 30 mg/kg) significantly inhibited both the increases in fibrosis score and 4-hydroxyproline content induced by DMN. Reverse transcription-polymerase chain reaction and Western blot analyses revealed that solubilized CoQ10 inhibitedmore » increases in the transforming growth factor-beta1 (TGF-beta1) mRNA and alpha-smooth muscle actin (alpha-SMA) protein by DMN. Interestingly, hepatic glutamate-cysteine ligase (GCL) and glutathione S-transferase A2 (GSTA2) were up-regulated in mice treated with CoQ10. Solubilized CoQ10 also up-regulated antioxidant enzymes such as catalytic subunits of GCL and GSTA2 via activating NF-E2 related factor2 (Nrf2)/antioxidant response element (ARE) in H4IIE hepatoma cells. Moreover, CoQ10's inhibition of alpha-SMA and TGF-beta1 expressions disappeared in Nrf2-null MEF cells. In contrast, Nrf2 overexpression significantly decreased the basal expression levels of alpha-SMA and TGF-beta1 in Nrf2-null MEF cells. These results demonstrated that solubilized CoQ10 inhibited DMN-induced liver fibrosis through suppression of TGF-beta1 expression via Nrf2/ARE activation.« less

  19. Cervical Cancer Cell Line Secretome Highlights the Roles of Transforming Growth Factor-Beta-Induced Protein ig-h3, Peroxiredoxin-2, and NRF2 on Cervical Carcinogenesis

    PubMed Central

    Zoidakis, Jerome; Makridakis, Manousos; Lygirou, Vasiliki; Mermelekas, George; Vougas, Konstantinos; Drakakis, Peter

    2017-01-01

    Cancer cells acquire unique secretome compositions that contribute to tumor development and metastasis. The aim of our study was to elucidate the biological processes involved in cervical cancer, by performing a proteomic analysis of the secretome from the following informative cervical cell lines: SiHa (HPV16+), HeLa (HPV18+), C33A (HPV−), and HCK1T (normal). Proteins were analyzed by 2D gel electrophoresis coupled to MALDI-TOF-MS. Enrichment of secreted proteins with characteristic profiles for each cell line was followed by the identification of differentially expressed proteins. Particularly, transforming growth factor-beta-induced protein ig-h3 (Beta ig-h3) and peroxiredoxin-2 (PRDX2) overexpression in the secretome of cancer cell lines was detected and confirmed by Western blot. Bioinformatics analysis identified the transcription factor NRF2 as a regulator of differentially expressed proteins in the cervical cancer secretome. NRF2 levels were measured by both Western blot and Multiple Reaction Monitoring (MRM) in the total cell extract of the four cell lines. NRF2 was upregulated in SiHa and C33A compared to HCK1T. In conclusion, the secreted proteins identified in cervical cancer cell lines indicate that aberrant NRF2-mediated oxidative stress response (OSR) is a prominent feature of cervical carcinogenesis. PMID:28261610

  20. Procyanidin B2 induces Nrf2 translocation and glutathione S-transferase P1 expression via ERKs and p38-MAPK pathways and protect human colonic cells against oxidative stress.

    PubMed

    Rodríguez-Ramiro, Ildefonso; Ramos, Sonia; Bravo, Laura; Goya, Luis; Martín, Maria Ángeles

    2012-10-01

    Procyanidin B2 (PB2) is a naturally occurring flavonoid widely found in cocoa, red wine and grape juice. Recent studies have suggested that PB2 could protect against oxidative stress- and chemical-induced injury in colonic cells by modulating the endogenous cellular defence. However, the precise mechanism for this protection is not fully understood. Herein, we examined the effect of PB2 on the expression of one of the major antioxidant/detoxificant enzymes related to intestinal protection, the glutathione S-transferase P1 (GSTP1), and the molecular mechanisms involved. Human colonic Caco-2 cells were treated with PB2 at different times and enzymatic activity, and mRNA and protein levels of GSTP1 were evaluated. The nuclear translocation of the transcription factor NF-erythroid 2-related factor (Nrf2) and the phosphorylation states of specific proteins central to intracellular signalling cascades were also investigated. PB2 induced the expression and activity of GSTP1 and the nuclear translocation of Nrf2. Interestingly, two important signalling proteins involved in Nrf2 translocation, the extracellular signal-regulated protein kinases (ERKs) and the p38 mitogen-activated protein kinase (MAPK) were also activated. Further experiments with specific inhibitors of both pathways confirmed their critical role in the beneficial effects induced by PB2. The present results show that PB2 protects against oxidative injury in colonic cells and up-regulate the expression of GSTP1 via a mechanism that involves ERK and p38 MAPK activation and Nrf2 translocation. These results provide a molecular basis for the potential contribution of PB2 in the prevention of oxidative stress-related intestinal injury and gut pathologies.

  1. Nitro-oleic acid ameliorates oxygen and glucose deprivation/re-oxygenation triggered oxidative stress in renal tubular cells via activation of Nrf2 and suppression of NADPH oxidase.

    PubMed

    Nie, Huibin; Xue, Xia; Liu, Gang; Guan, Guangju; Liu, Haiying; Sun, Lina; Zhao, Long; Wang, Xueling; Chen, Zhixin

    2016-01-01

    Nitroalkene derivative of oleic acid (OA-NO 2 ), due to its ability to mediate revisable Michael addition, has been demonstrated to have various biological properties and become a therapeutic agent in various diseases. Though its antioxidant properties have been reported in different models of acute kidney injury (AKI), the mechanism by which OA-NO 2 attenuates intracellular oxidative stress is not well investigated. Here, we elucidated the anti-oxidative mechanism of OA-NO 2 in an in vitro model of renal ischemia/reperfusion (I/R) injury. Human tubular epithelial cells were subjected to oxygen and glucose deprivation/re-oxygenation (OGD/R) injury. Pretreatment with OA-NO 2 (1.25 μM, 45 min) attenuated OGD/R triggered reactive oxygen species (ROS) generation and subsequent mitochondrial membrane potential disruption. This action was mediated via up-regulating endogenous antioxidant defense components including superoxide dismutase (SOD1), heme oxygenase 1 (HO-1), and γ-glutamyl cysteine ligase modulatory subunits (GCLM). Moreover, subcellular fractionation analyses demonstrated that OA-NO 2 promoted nuclear translocation of nuclear factor-E2- related factor-2 (Nrf2) and Nrf2 siRNA partially abrogated these protective effects. In addition, OA-NO 2 inhibited NADPH oxidase activation and NADPH oxidase 4 (NOX4), NADPH oxidase 2 (NOX2) and p22 phox up-regulation after OGD/R injury, which was not relevant to Nrf2. These results contribute to clarify that the mechanism of OA-NO 2 reno-protection involves both inhibition of NADPH oxidase activity and induction of SOD1, Nrf2-dependent HO-1, and GCLM.

  2. Diesel Exhaust Particulate Extracts Inhibit Transcription of Nuclear Respiratory Factor-1 and Cell Viability in Human Umbilical Vein Endothelial Cells

    PubMed Central

    Mattingly, Kathleen A.; Klinge, Carolyn M.

    2011-01-01

    Endothelial dysfunction precedes cardiovascular disease and is accompanied by mitochondrial dysfunction. Here we tested the hypothesis that diesel exhaust particulate extracts (DEPEs), prepared from a truck run at different speeds and engine loads, would inhibit genomic estrogen receptor activation of nuclear respiratory factor-1 (NRF-1) transcription in human umbilical vein endothelial cells (HUVECs). Additionally, we examined how DEPEs affect NRF-1 regulated TFAM expression and, in turn, Tfam-regulated mtDNA-encoded cytochrome c oxidase subunit I (COI, MTCO1) and NADH dehydrogenase subunit I (NDI) expression as well as cell proliferation and viability. We report that 17β-estradiol (E2), 4-hydroxytamoxifen (4-OHT), and raloxifene increased NRF-1 transcription in HUVECs in an ER-dependent manner. DEPEs inhibited NRF-1 transcription and this suppression was not ablated by concomitant treatment with E2, 4-OHT, or raloxifene, indicating that the effect was not due to inhibition of ER activity. While E2 increased HUVEC proliferation and viability, DEPEs inhibited viability but not proliferation. Resveratrol increased NRF-1 transcription in an ER-dependent manner in HUVECs, and ablated DEPE inhibition of basal NRF-1 expression. Given that NRF-1 is a key nuclear transcription factor regulating genes involved in mitochondrial activity and biogenesis, these data suggest that DEPEs may adversely affect mitochondrial function leading to endothelial dysfunction and resveratrol may block these effects. PMID:22105178

  3. (-)-7(S)-hydroxymatairesinol protects against tumor necrosis factor-α-mediated inflammation response in endothelial cells by blocking the MAPK/NF-κB and activating Nrf2/HO-1.

    PubMed

    Yang, Di; Xiao, Chen-Xi; Su, Zheng-Hua; Huang, Meng-Wei; Qin, Ming; Wu, Wei-Jun; Jia, Wan-Wan; Zhu, Yi-Zhun; Hu, Jin-Feng; Liu, Xin-Hua

    2017-08-15

    Endothelial inflammation is an increasingly prevalent condition in the pathogenesis of many cardiovascular diseases. (-)-7(S)-hydroxymatairesinol (7-HMR), a naturally occurring plant lignan, possesses both antioxidant and anti-cancer properties and therefore would be a good strategy to suppress tumor necrosis factor-α (TNF-α)-mediated inflammation in vascular endothelial cells (VECs). The objective of this study is to evaluate for its anti-inflammatory effect on TNF-α-stimulated VECs and underling mechanisms. The effect of the 7-HMR on suppression of TNF-α-induced inflammation mediators in VECs were determined by qRT-PCR and Western blot. MAPKs and phosphorylation of Akt, HO-1 and NF-κB p65 were examined using Western blot. Nuclear localisation of NF-κB was also examined using Western blot and immunofluorescence. Here we found that 7-HMR could suppress TNF-α-induced inflammatory mediators, such as vascularcelladhesion molecule-1, interleukin-6 and inducible nitric oxide synthase expression both in mRNA and protein levels, and concentration-dependently attenuated reactive oxidase species generation. We further identified that 7-HMR remarkably induced superoxide dismutase and heme oxygenase-1 expression associated with degradation of Kelch-like ECH-associated protein 1 (keap1) and up-regulated nuclear factor erythroid 2-related factor 2 (Nrf2). In addition, 7-HMR time- and concentration-dependently attenuated TNF-α-induced phosphorylation of extracellular signal-regulated kinase 1/2 (ERK) and Akt, but not p38, or c-Jun N-terminal kinase 1/2. Moreover, 7-HMR significantly suppressed TNF-α-mediated nuclear factor-κB (NF-κB) activation by inhibiting phosphorylation and nuclear translocation of NF-κB p65. Our results demonstrated that 7-HMR inhibited TNF-α-stimulated endothelial inflammation, at least in part, through inhibition of NF-κB activation and upregulation of Nrf2-antioxidant response element signaling pathway, suggesting 7-HMR might be used as a

  4. Cerebroprotection of Flavanol (−)-Epicatechin after Traumatic Brain Injury via Nrf2-dependent and –independent Pathways

    PubMed Central

    Cheng, Tian; Wang, Wenzhu; Li, Qian; Han, Xiaoning; Xing, Jing; Qi, Cunfang; Lan, Xi; Wan, Jieru; Potts, Alexa; Guan, Fangxia; Wang, Jian

    2016-01-01

    Traumatic brain injury (TBI), which leads to disability, dysfunction, and even death, is a prominent health problem worldwide with no effective treatment. A brain-permeable flavonoid named (−)-epicatechin (EC) modulates redox/oxidative stress and has been shown to be beneficial for vascular and cognitive function in humans and for ischemic and hemorrhagic stroke in rodents. Here we examined whether EC is able to protect the brain against TBI-induced brain injury in mice and if so, whether it exerts neuroprotection by modulating the NF-E2-related factor (Nrf2) pathway. We used the controlled cortical impact model to mimic TBI. EC was administered orally at 3 h after TBI and then every 24 h for either 3 or 7 days. We evaluated lesion volume, brain edema, white matter injury, neurologic deficits, cognitive performance and emotion-like behaviors, neutrophil infiltration, reactive oxygen species (ROS), and a variety of injury-related protein markers. Nrf2 knockout mice were used to determine the role of the Nrf2 signaling pathway after EC treatment. In wild-type mice, EC significantly reduced lesion volume, edema, and cell death and improved neurologic function on days 3 and 28; cognitive performance and depression-like behaviors were also improved with EC administration. In addition, EC reduced white matter injury, heme oxygenase-1 expression, and ferric iron deposition after TBI. These changes were accompanied by attenuation of neutrophil infiltration and oxidative insults, reduced activity of matrix metalloproteinase 9, decreased Keap 1 expression, increased Nrf2 nuclear accumulation, and increased expression of superoxide dismutase 1 and quinone 1. However, EC did not significantly reduce lesion volume or improve neurologic deficits in Nrf2 knockout mice after TBI. Our results show that EC protects the TBI brain by activating the Nrf2 pathway, inhibiting heme oxygenase-1 protein expression, and reducing iron deposition. The latter two effects could represent an

  5. Activation of anti-oxidant Nrf2 signaling by enone analogues of curcumin.

    PubMed

    Deck, Lorraine M; Hunsaker, Lucy A; Vander Jagt, Thomas A; Whalen, Lisa J; Royer, Robert E; Vander Jagt, David L

    2018-01-01

    Inflammation and oxidative stress are common in many chronic diseases. Targeting signaling pathways that contribute to these conditions may have therapeutic potential. The transcription factor Nrf2 is a major regulator of phase II detoxification and anti-oxidant genes as well as anti-inflammatory and neuroprotective genes. Nrf2 is widespread in the CNS and is recognized as an important regulator of brain inflammation. The natural product curcumin exhibits numerous biological activities including ability to induce the expression of Nrf2-dependent phase II and anti-oxidant enzymes. Curcumin has been examined in a number of clinical studies with limited success, mainly owing to limited bioavailability and rapid metabolism. Enone analogues of curcumin were examined with an Nrf2 reporter assay to identify Nrf2 activators. Analogues were separated into groups with a 7-carbon dienone spacer, as found in curcumin; a 5-carbon enone spacer with and without a ring; and a 3-carbon enone spacer. Activators of Nrf2 were found in all three groups, many of which were more active than curcumin. Dose-response studies demonstrated that a range of substituents on the aromatic rings of these enones influenced not only the sensitivity to activation, reflected in EC 50 values, but also the extent of activation, which suggests that multiple mechanisms are involved in the activation of Nrf2 by these analogues. Copyright © 2017. Published by Elsevier Masson SAS.

  6. In-Vitro Analysis of Glucose and Quercetin Effects on m-TOR and Nrf-2 Expression in HepG2 Cell Line (Diabetes and Cancer Connection).

    PubMed

    Yarahmadi, Amir; Khademi, Fatemeh; Mostafavi-Pour, Zohreh; Zal, Fatemeh

    2018-05-21

    Some types of cancers show a strong relationship with diabetes and play a central role in mortality in the patient population suffering from diabetes mellitus. In this study, HepG2 cells have been used to investigate the toxic effects of hyperglycemia and/or quercetin (Q) on mammalian target of rapamycin (m-TOR) and nuclear factor erythroid 2-related factor 2 (Nrf-2) expression as central molecules involved in cancer. HepG2 cells were cultured with different concentrations of glucose (5.5, 30, and 50 mM) and/or Q (25 µM) for 48 and 72 h. Effects of glucose and/or Q on m-TOR and Nrf-2 expression were assayed by quantitative real-time PCR (qRT-PCR). qRT-PCR results revealed that 30 and 50 mM of glucose increased m-TOR expression at 48 h, although after 72 h, only 30 mM had an increasing effect. At 50 mM, glucose-induced Nrf-2 gene expression after both 48 and 72 h. The results also showed that 25 µM of Q reduced m-TOR and Nrf-2 expression at both 30 and 50 mM after 48 and 72 h incubation. Q has potential effects on reducing oxidative stress caused by hyperglycemia and during diabetes may be able to modulate some carcinogenic signaling pathways.

  7. Nicotine and cigarette smoke modulate Nrf2-BDNF-dopaminergic signal and neurobehavioral disorders in adult rat cerebral cortex.

    PubMed

    Naha, Nibedita; Gandhi, D N; Gautam, A K; Prakash, J Ravi

    2018-05-01

    Nicotine and cigarette smoking (CS) are associated with addiction behavior, drug-seeking, and abuse. However, the mechanisms that mediate this association especially, the role of brain-derived neurotrophic factor (BDNF), dopamine (DA), and nuclear factor erythroid 2-related factor 2 (Nrf2) signaling in the cerebral cortex, are not fully known. Therefore, we hypothesized that overexpression of BDNF and DA, and suppression of Nrf2 contribute to several pathological and behavioral alterations in adult cerebral cortex. Methodology/Principal Observations: We treated Wistar rats with different doses of oral nicotine and passive CS for 4-week (short-term) and 12-week (long-term) duration, where doses closely mimic the human smoking scenario. Our result showed dose-dependent association of anxiogenic and depressive behavior, and cognitive interference with neurodegeneration and DNA damage in the cerebral cortex upon exposure to nicotine/CS as compared to the control. Further, the results are linked to upregulation of oxidative stress, overexpression of BDNF, DA, and DA marker, tyrosine hydroxylase (TH), with concomitant downregulation of ascorbate and Nrf2 expression in the exposed cerebral cortex when compared with the control. Overall, our data strongly suggest that the intervention of DA and BDNF, and depletion of antioxidants are important factors during nicotine/CS-induced cerebral cortex pathological changes leading to neurobehavioral impairments, which could underpin the novel therapeutic approaches targeted at tobacco smoking/nicotine's neuropsychological disorders including cognition and drug addiction.

  8. Long-term Autophagy and Nrf2 Signaling in the Hippocampi of Developing Mice after Carbon Ion Exposure

    NASA Astrophysics Data System (ADS)

    Ye, Fei; Zhao, Ting; Liu, Xiongxiong; Jin, Xiaodong; Liu, Xinguo; Wang, Tieshan; Li, Qiang

    2015-12-01

    To explore charged particle radiation-induced long-term hippocampus damage, we investigated the expression of autophagy and antioxidant Nrf2 signaling-related proteins in the mouse hippocampus after carbon ion radiation. Heads of immature female Balb/c mice were irradiated with carbon ions of different LETs at various doses. Behavioral tests were performed on the mice after maturation. Acute and chronic expression of LC3-II, p62/SQSTM1, nuclear Nrf2, activated caspase-3 and the Bax/Bcl-2 ratio were measured in the hippocampi. Secondary X-ray insult was adopted to amplify potential damages. Long-term behavioral changes were observed in high-LET carbon ion-irradiated mice. There were no differences in the rates of LC3-II induction and p62/SQSTM1 degradation compared to the control group regardless of whether the mice received the secondary X-ray insult. A high nuclear Nrf2 content and low apoptosis level in hippocampal cells subjected to secondary X-rays were observed for the mice exposed to relatively low-LET carbon ions. Therefore, carbon ion exposure in the immature mouse led to an LET-dependent behavioral change after maturation. Although autophagy was intact, the persistently high nuclear Nrf2 content in the hippocampus might account for the unchanged behavioral pattern in mice exposed to the relatively low-LET carbon ions and the subsequent increased radioresistance of the hippocampus.

  9. Ezetimibe, an NPC1L1 inhibitor, is a potent Nrf2 activator that protects mice from diet-induced nonalcoholic steatohepatitis.

    PubMed

    Lee, Da Hyun; Han, Dai Hoon; Nam, Ki Taek; Park, Jeong Su; Kim, Soo Hyun; Lee, Milim; Kim, Gyuri; Min, Byung Soh; Cha, Bong-Soo; Lee, Yu Seol; Sung, Su Haeng; Jeong, Haengdueng; Ji, Hye Won; Lee, Moon Joo; Lee, Jae Sung; Lee, Hui-Young; Chun, Yoomi; Kim, Joungmok; Komatsu, Masaaki; Lee, Yong-Ho; Bae, Soo Han

    2016-10-01

    Oxidative stress is important for the pathogenesis of nonalcoholic fatty liver disease (NAFLD), a chronic disease that ranges from hepatic steatosis to nonalcoholic steatohepatitis (NASH). The nuclear factor erythroid 2-related factor 2-Kelch-like ECH associated protein 1 (Nrf2-Keap1) pathway is essential for cytoprotection against oxidative stress. In this study, we found that oxidative stress or inflammatory biomarkers and TUNEL positive cells were markedly increased in NASH patients compared to normal or simple steatosis. In addition, we identified that the hepatic mRNA levels of Nrf2 target genes such as Nqo-1 and GSTA-1 were significantly increased in NASH patients. Ezetimibe, a drug approved by the Food and Drug Administration for the treatment of hypercholesterolemia, improves NAFLD and alleviates oxidative stress. However, the precise mechanism of its antioxidant function remains largely unknown. We now demonstrate that ezetimibe activates Nrf2-Keap1 pathway which was dependent of autophagy adaptor protein p62, without causing cytotoxicity. Ezetimibe activates AMP-activated protein kinase (AMPK), which in turn phosphorylates p62 (p-S351) via their direct interaction. Correspondingly, Ezetimibe protected liver cells from saturated fatty acid-induced apoptotic cell death through p62-dependent Nrf2 activation. Furthermore, its role as an Nrf2 activator was supported by methione- and choline- deficient (MCD) diet-induced NASH mouse model, showing that ezetimibe decreased the susceptibility of the liver to oxidative injury. These data demonstrate that the molecular mechanisms underlying ezetimibe's antioxidant role in the pathogenesis of NASH. Copyright © 2016 Elsevier Inc. All rights reserved.

  10. Integrated transcriptomic and proteomic analyses uncover regulatory roles of Nrf2 in the kidney

    PubMed Central

    Walsh, Joanne; Jenkins, Rosalind E.; Wong, Michael H. L.; Rowe, Cliff; Ricci, Emanuele; Ressel, Lorenzo; Fang, Yongxiang; Demougin, Philippe; Vukojevic, Vanja; O’Neill, Paul M.; Goldring, Christopher E.; Kitteringham, Neil R.; Park, B. Kevin; Odermatt, Alex; Copple, Ian M.

    2015-01-01

    The transcription factor Nrf2 exerts protective effects in numerous experimental models of acute kidney injury, and is a promising therapeutic target in chronic kidney disease. To provide a detailed insight into the regulatory roles of Nrf2 in the kidney, we performed integrated transcriptomic and proteomic analyses of kidney tissue from wild-type and Nrf2 knockout mice treated with the Nrf2 inducer methyl-2-cyano-3,12-dioxooleano-1,9-dien-28-oate (CDDO-Me, also known as bardoxolone methyl). After 24 hours, analyses identified 2561 transcripts and 240 proteins that were differentially expressed in the kidneys of Nrf2 knockout mice, compared to wild-type counterparts, and 3122 transcripts and 68 proteins that were differentially expressed in wild-type mice treated with CDDO-Me, compared to vehicle control. In light of their sensitivity to genetic and pharmacological modulation of renal Nrf2 activity, genes/proteins that regulate xenobiotic disposition, redox balance, the intra/extracellular transport of small molecules, and the supply of NADPH and other cellular fuels were found to be positively regulated by Nrf2 in the kidney. This was verified by qPCR, immunoblotting, pathway analysis and immunohistochemistry. In addition, the levels of NADPH and glutathione were found to be significantly decreased in the kidneys of Nrf2 knockout mice. Thus, Nrf2 regulates genes that coordinate homeostatic processes in the kidney, highlighting its potential as a novel therapeutic target. PMID:26422507

  11. Nrf1 CNC-bZIP protein promotes cell survival and nucleotide excision repair through maintaining glutathione homeostasis.

    PubMed

    Han, Weinong; Ming, Mei; Zhao, Rui; Pi, Jingbo; Wu, Chunli; He, Yu-Ying

    2012-05-25

    Skin cancer is the most common cancer in the United States. Its major environmental risk factor is UVB radiation in sunlight. In response to UVB damage, epidermal keratinocytes activate a specific repair pathway, i.e. nucleotide excision repair, to remove UVB-induced DNA lesions. However, the regulation of UVB response is not fully understood. Here we show that the long isoform of the nuclear factor erythroid 2-related factor 1 (Nrf1, also called NFE2L1), a cytoprotective transcription factor critical for the expression of multiple antioxidant response element-dependent genes, plays an important role in the response of keratinocytes to UVB. Nrf1 loss sensitized keratinocytes to UVB-induced apoptosis by up-regulating the expression of the proapoptotic Bcl-2 family member Bik through reducing glutathione levels. Knocking down Bik reduced UVB-induced apoptosis in Nrf1-inhibited cells. In UVB-irradiated surviving cells, however, disruption of Nrf1 impaired nucleotide excision repair through suppressing the transcription of xeroderma pigmentosum C (XPC), a factor essential for initiating the global genome nucleotide excision repair by recognizing the DNA lesion and recruiting downstream factors. Nrf1 enhanced XPC expression by increasing glutathione availability but was independent of the transcription repressor of XPC. Adding XPC or glutathione restored the DNA repair capacity in Nrf1-inhibited cells. Finally, we demonstrate that Nrf1 levels are significantly reduced by UVB radiation in mouse skin and are lower in human skin tumors than in normal skin. These results indicate a novel role of Nrf1 in UVB-induced DNA damage repair and suggest Nrf1 as a tumor suppressor in the skin.

  12. NRF2 Orchestrates the Metabolic Shift during Induced Pluripotent Stem Cell Reprogramming

    PubMed Central

    Hawkins, Kate E.; Joy, Shona; Delhove, Juliette M.K.M.; Kotiadis, Vassilios N.; Fernandez, Emilio; Fitzpatrick, Lorna M.; Whiteford, James R.; King, Peter J.; Bolanos, Juan P.; Duchen, Michael R.; Waddington, Simon N.; McKay, Tristan R.

    2016-01-01

    Summary The potential of induced pluripotent stem cells (iPSCs) in disease modeling and regenerative medicine is vast, but current methodologies remain inefficient. Understanding the cellular mechanisms underlying iPSC reprogramming, such as the metabolic shift from oxidative to glycolytic energy production, is key to improving its efficiency. We have developed a lentiviral reporter system to assay longitudinal changes in cell signaling and transcription factor activity in living cells throughout iPSC reprogramming of human dermal fibroblasts. We reveal early NF-κB, AP-1, and NRF2 transcription factor activation prior to a temporal peak in hypoxia inducible factor α (HIFα) activity. Mechanistically, we show that an early burst in oxidative phosphorylation and elevated reactive oxygen species generation mediates increased NRF2 activity, which in turn initiates the HIFα-mediated glycolytic shift and may modulate glucose redistribution to the pentose phosphate pathway. Critically, inhibition of NRF2 by KEAP1 overexpression compromises metabolic reprogramming and results in reduced efficiency of iPSC colony formation. PMID:26904936

  13. Sulforaphane prevents bleomycin‑induced pulmonary fibrosis in mice by inhibiting oxidative stress via nuclear factor erythroid 2‑related factor‑2 activation.

    PubMed

    Yan, Bingdi; Ma, Zhongsen; Shi, Shaomin; Hu, Yuxin; Ma, Tiangang; Rong, Gao; Yang, Junling

    2017-06-01

    Lung fibrosis is associated with inflammation, apoptosis and oxidative damage. The transcription factor nuclear factor erythroid 2‑related factor‑2 (Nrf2) prevents damage to cells from oxidative stress by regulating the expression of antioxidant proteins. Sulforaphane (SFN), an Nrf2 activator, additionally regulates excessive oxidative stress by promoting the expression of endogenous antioxidants. The present study investigated if SFN protects against lung injury induced by bleomycin (BLM). The secondary aim of the present study was to assess if this protection mechanism involves upregulation of Nrf2 and its downstream antioxidants. Pulmonary fibrosis was induced in C57/BL6 mice by intratracheal instillation of BLM. BLM and age‑matched control mice were treated with or without a daily dose of 0.5 mg/kg SFN until sacrifice. On days 7 and 28, mice were assessed for induction of apoptosis, inflammation, fibrosis, oxidative damage and Nrf2 expression in the lungs. The lungs were investigated with histological techniques including haematoxylin and eosin staining, Masson's trichrome staining and terminal deoxynucleotidyl transferase UTP nick end labeling. Inflammatory, fibrotic and apoptotic processes were confirmed by western blot analysis for interleukin‑1β, tumor necrosis factor‑α, transforming growth factor‑β and caspase‑3 protein expressions. Furthermore, protein levels of 3‑nitro‑tyrosine, 4‑hydroxynonenal, superoxide dismutase 1 and catalase were investigated by western blot analysis. It was demonstrated that pulmonary fibrosis induced by BLM significantly increased apoptosis, inflammation, fibrosis and oxidative stress in the lungs at days 7 and 28. Notably, SFN treatment significantly attenuated the infiltration of the inflammatory cells, collagen accumulation, epithelial cell apoptosis and oxidative stress in the lungs. In addition, SFN treatment increased expression of the Nrf2 gene and its downstream targets. In conclusion, these

  14. Omega-3 fatty acids protect the brain against ischemic injury by activating Nrf2 and upregulating heme oxygenase 1.

    PubMed

    Zhang, Meijuan; Wang, Suping; Mao, Leilei; Leak, Rehana K; Shi, Yejie; Zhang, Wenting; Hu, Xiaoming; Sun, Baoliang; Cao, Guodong; Gao, Yanqin; Xu, Yun; Chen, Jun; Zhang, Feng

    2014-01-29

    Ischemic stroke is a debilitating clinical disorder that affects millions of people, yet lacks effective neuroprotective treatments. Fish oil is known to exert beneficial effects against cerebral ischemia. However, the underlying protective mechanisms are not fully understood. The present study tests the hypothesis that omega-3 polyunsaturated fatty acids (n-3 PUFAs) attenuate ischemic neuronal injury by activating nuclear factor E2-related factor 2 (Nrf2) and upregulating heme oxygenase-1 (HO-1) in both in vitro and in vivo models. We observed that pretreatment of rat primary neurons with docosahexaenoic acid (DHA) significantly reduced neuronal death following oxygen-glucose deprivation. This protection was associated with increased Nrf2 activation and HO-1 upregulation. Inhibition of HO-1 activity with tin protoporphyrin IX attenuated the protective effects of DHA. Further studies showed that 4-hydroxy-2E-hexenal (4-HHE), an end-product of peroxidation of n-3 PUFAs, was a more potent Nrf2 inducer than 4-hydroxy-2E-nonenal derived from n-6 PUFAs. In an in vivo setting, transgenic mice overexpressing fatty acid metabolism-1, an enzyme that converts n-6 PUFAs to n-3 PUFAs, were remarkably resistant to focal cerebral ischemia compared with their wild-type littermates. Regular mice fed with a fish oil-enhanced diet also demonstrated significant resistance to ischemia compared with mice fed with a regular diet. As expected, the protection was associated with HO-1 upregulation, Nrf2 activation, and 4-HHE generation. Together, our data demonstrate that n-3 PUFAs are highly effective in protecting the brain, and that the protective mechanisms involve Nrf2 activation and HO-1 upregulation by 4-HHE. Further investigation of n-3 PUFA neuroprotective mechanisms may accelerate the development of stroke therapies.

  15. EGCG evokes Nrf2 nuclear translocation and dampens PTP1B expression to ameliorate metabolic misalignment under insulin resistance condition.

    PubMed

    Mi, Yashi; Zhang, Wentong; Tian, Haoyu; Li, Runnan; Huang, Shuxian; Li, Xingyu; Qi, Guoyuan; Liu, Xuebo

    2018-03-01

    As a major nutraceutical component of green tea (-)-epigallocatechin-3-gallate (EGCG) has attracted interest from scientists due to its well-documented antioxidant and antiobesity bioactivities. In the current study, we aimed to investigate the protective effect of EGCG on metabolic misalignment and in balancing the redox status in mice liver and HepG2 cells under insulin resistance condition. Our results indicated that EGCG accelerates the glucose uptake and evokes IRS-1/Akt/GLUT2 signaling pathway via dampening the expression of protein tyrosine phosphatase 1B (PTP1B). Consistently, ectopic expression of PTP1B by Ad-PTP1B substantially impaired EGCG-elicited IRS-1/Akt/GLUT2 signaling pathway. Moreover, EGCG co-treatment stimulated nuclear translocation of Nrf2 by provoking P13K/AKT signaling pathway and thus modulated the downstream expressions of antioxidant enzymes such as HO-1 and NQO-1 in HepG2 cells. Furthermore, knockdown Nrf2 by small interfering RNA (siRNA) notably enhanced the expression of PTP1B and blunt EGCG-stimulated glucose uptake. Consistent with these results, in vivo study revealed that EGCG supplement significantly ameliorated high-fat and high-fructose diet (HFFD)-triggered insulin resistance and oxidative stress by up-regulating the IRS-1/AKT and Keap1/Nrf2 transcriptional pathways. Administration of an appropriate chemopreventive agent, such as EGCG, could potentially serve as an additional therapeutic intervention in the arsenal against obesity.

  16. Liquiritigenin and liquiritin alleviated MCT-induced HSOS by activating Nrf2 antioxidative defense system.

    PubMed

    Huang, Zhenlin; Sheng, Yuchen; Chen, Minwei; Hao, Zhanxia; Hu, Feifei; Ji, Lili

    2018-06-14

    Hepatic sinusoidal obstruction syndrome (HSOS) is a serious and life-threatening liver disease. Liquiritigenin (LG) and liquiritin (LQ) are natural flavonoids distributed in Glycyrrhizae Radix et Rhizoma (Gan-cao). This study aims to investigate the protective effect and mechanism of LG and LQ against monocrotaline (MCT)-induced HSOS. Results of serum alanine/aspartate aminotransferases (ALT/AST) activities, liver histological evaluation and scanning electron microscope observation, and hepatic metalloproteinase-9 (MMP-9) expression demonstrated that LG and LQ both alleviated HSOS induced by MCT in rats. Results of hepatic reactive oxygen species (ROS), malondialdehyde (MDA), 4-hydroxynonenal (4-HNE), oxidized glutathione (GSSG) and reduced glutathione (GSH) contents, glutathione reductase (GR) and superoxide dismutase (SOD) activities showed that LG and LQ attenuated MCT-induced liver oxidative stress injury. Furthermore, LG and LQ were found to promote Nrf2 nuclear translocation and lead to the increased expression of Nrf2 downstream antioxidative genes. Molecule docking analysis indicated the potential interaction of LG and LQ with Nrf2 binding site in the kelch-like ECH-associated protein-1 (Keap1) protein. Finally, Nrf2 knock-out mice were used. The results showed that LG and LQ both alleviated MCT-induced HSOS in wild-type mice, but such protection was totally diminished in Nrf2 knock-out mice. In conclusion, our study revealed that LG and LQ alleviated MCT-induced HSOS by inducing the activation of hepatic Nrf2 antioxidative defense system. Copyright © 2018. Published by Elsevier Inc.

  17. The Nrf1 CNC-bZIP protein is regulated by the proteasome and activated by hypoxia.

    PubMed

    Chepelev, Nikolai L; Bennitz, Joshua D; Huang, Ting; McBride, Skye; Willmore, William G

    2011-01-01

    Nrf1 (nuclear factor-erythroid 2 p45 subunit-related factor 1) is a transcription factor mediating cellular responses to xenobiotic and pro-oxidant stress. Nrf1 regulates the transcription of many stress-related genes through the electrophile response elements (EpREs) located in their promoter regions. Despite its potential importance in human health, the mechanisms controlling Nrf1 have not been addressed fully. We found that proteasomal inhibitors MG-132 and clasto-lactacystin-β-lactone stabilized the protein expression of full-length Nrf1 in both COS7 and WFF2002 cells. Concomitantly, proteasomal inhibition decreased the expression of a smaller, N-terminal Nrf1 fragment, with an approximate molecular weight of 23 kDa. The EpRE-luciferase reporter assays revealed that proteasomal inhibition markedly inhibited the Nrf1 transactivational activity. These results support earlier hypotheses that the 26 S proteasome processes Nrf1 into its active form by removing its inhibitory N-terminal domain anchoring Nrf1 to the endoplasmic reticulum. Immunoprecipitation demonstrated that Nrf1 is ubiquitinated and that proteasomal inhibition increased the degree of Nrf1 ubiquitination. Furthermore, Nrf1 protein had a half-life of approximately 5 hours in COS7 cells. In contrast, hypoxia (1% O(2)) significantly increased the luciferase reporter activity of exogenous Nrf1 protein, while decreasing the protein expression of p65, a shorter form of Nrf1, known to act as a repressor of EpRE-controlled gene expression. Finally, the protein phosphatase inhibitor okadaic acid activated Nrf1 reporter activity, while the latter was repressed by the PKC inhibitor staurosporine. Collectively, our data suggests that Nrf1 is controlled by several post-translational mechanisms, including ubiquitination, proteolytic processing and proteasomal-mediated degradation as well as by its phosphorylation status. © 2011 Chepelev et al.

  18. The effect of ex vivo CDDO-Me activation on nuclear factor erythroid 2-related factor 2 pathway in white blood cells from patients with septic shock.

    PubMed

    Noel, Sanjeev; Zheng, Laura; Navas-Acien, Ana; Fuchs, Ralph J

    2014-11-01

    Nuclear factor erythroid 2-related factor 2 (NRF2) has been shown to protect against experimental sepsis in mice and lipopolysaccharide (LPS)-induced inflammation in ex vivo white blood cells from healthy subjects by upregulating cellular antioxidant genes. The objective of this study was to test the hypothesis that ex vivo methyl 2-cyano-3,12-dioxoolean-1,9-dien-28-oate (CDDO-Me) activates NRF2-regulated antioxidant genes in white blood cells from patients with septic shock and protects against LPS-induced inflammation and reactive oxidative species production. Peripheral blood was collected from 18 patients with septic shock who were being treated in medical and surgical intensive care units. Real-time polymerase chain reaction was used to quantify the expression of NRF2 target genes (NQO1, HO-1, GCLM, and FTL) and IL-6 in peripheral blood mononuclear cells (PBMCs), monocytes, and neutrophils after CDDO-Me treatment alone or after subsequent LPS exposure. Superoxide anion (O2) was measured to assess the effect of CDDO-Me pretreatment on subsequent LPS exposure. Treatment with CDDO-Me increased the gene expression of NQO1 (P = 0.04) and decreased the expression of HO-1 (P = 0.03) in PBMCs from patients with septic shock. Purified monocytes exhibited significant increases in the expression of NQO1 (P = 0.01) and GCLM (P = 0.003) after CDDO-Me treatment. Levels of other NRF2 target genes (HO-1 and FTL) remained similar to those of vehicle-treated cells. Peripheral blood mononuclear cells showed a trend toward increased IL-6 gene expression after CDDO-Me treatment, whereas purified monocytes showed a trend toward decreased IL-6. There was no discernible trend in the IL-6 expression subsequent to LPS treatment in either vehicle-treated or CDDO-Me-treated PBMCs and monocytes. Treatment with CDDO-Me significantly increased O2 production in PBMCs (P = 0.04). Although CDDO-Me pretreatment significantly attenuated O2 production to subsequent LPS exposure (P = 0.03), the

  19. EX4 stabilizes and activates Nrf2 via PKCδ, contributing to the prevention of oxidative stress-induced pancreatic beta cell damage

    DOE Office of Scientific and Technical Information (OSTI.GOV)

    Kim, Mi-Hwi; Kim, Eung-Hwi

    Oxidative stress in pancreatic beta cells can inhibit insulin secretion and promote apoptotic cell death. Exendin-4 (EX4), a glucagon-like peptide-1 receptor agonist, can suppress beta cell apoptosis, improve beta cell function and protect against oxidative damage. In this study, we investigated the molecular mechanisms for antioxidative effects of EX4 in pancreatic beta cells. INS-1 cells, a rat insulinoma cell line, were pretreated with EX4 and exposed to palmitate or H{sub 2}O{sub 2}. Reactive oxygen species (ROS) production, and glutathione and insulin secretion were measured. The mRNA and protein expression levels of antioxidant genes were examined. The level of nuclear factormore » erythroid 2-related factor 2 (Nrf2), its binding to antioxidant response element (ARE), and its ubiquination in the presence of EX4 were determined. The Nrf2 signaling pathway was determined using rottlerin (protein kinase [PK]Cδ inhibitor), H89 (PKA inhibitor) and LY294002 (phosphatidylinositide 3-kinase [PI3K] inhibitor). EX4 treatment decreased ROS production, recovered cellular glutathione levels and insulin secretion in the presence of oxidative stress in INS-1 cells. The expression levels of glutamate-cysteine ligase catalytic subunit and heme oxygenase-1 were increased by EX4 treatment. EX4 promoted Nrf2 translocation, ARE binding activity and enhanced stabilization of Nrf2 by inhibition of ubiquitination. Knockdown of Nrf2 abolished the effect of EX4 on increased insulin secretion. Inhibition of PKCδ attenuated Nrf2 translocation and antioxidative gene expression by EX4 treatment. We suggest that EX4 activates and stabilizes Nrf2 through PKCδ activation, contributing to the increase of antioxidant gene expression and consequently improving beta cell function in the presence of oxidative stress. - Highlights: • EX4 protects against oxidative stress-induced pancreatic beta cell dysfunction. • EX4 increases antioxidant gene expression. • Antioxidative effect of EX4

  20. 5-HMF attenuates striatum oxidative damage via Nrf2/ARE signaling pathway following transient global cerebral ischemia.

    PubMed

    Ya, Bai-Liu; Li, Hong-Fang; Wang, Hai-Ying; Wu, Fei; Xin, Qing; Cheng, Hong-Ju; Li, Wen-Juan; Lin, Na; Ba, Zai-Hua; Zhang, Ru-Juan; Liu, Qian; Li, Ya-Nan; Bai, Bo; Ge, Feng

    2017-01-01

    Recent studies have shown 5-hydroxymethyl-2-furfural (5-HMF) has favorable biological effects, and its neuroprotection in a variety of neurological diseases has been noted. Our previous study showed that treatment of 5-HMF led to protection against permanent global cerebral ischemia. However, the underlying mechanisms in cerebral ischemic injury are not fully understood. This study was conducted to investigate the neuroprotective effect of 5-HMF and elucidate the nuclear factor erythroid 2-related factor 2 (Nrf2)/antioxidant response element (ARE) signaling pathway mechanism in the striatum after transient global cerebral ischemia. C57BL/6 mice were subjected to bilateral common carotid artery occlusion for 20 min and sacrificed 24 h after reperfusion. 5-HMF (12 mg/kg) or an equal volume of vehicle was intraperitoneally injected 30 min before ischemia and 5 min after the onset of reperfusion. At 24 h after reperfusion, neurological function was evaluated by neurological disability status scale, locomotor activity test and inclined beam walking test. Histological injury of the striatum was observed by cresyl violet staining and terminal deoxynucleotidyl transferase (TdT)-mediated dNTP nick end labeling (TUNEL) staining. Oxidative stress was evaluated by the carbonyl groups introduced into proteins, and malondialdehyde (MDA) levels. An enzyme-linked immunosorbent assay (ELISA)-based measurement was used to detect Nrf2 DNA binding activity. Nrf2 and its downstream ARE pathway protein expression such as heme oxygenase-1, NAD (P)H:quinone oxidoreductase 1, glutamate-cysteine ligase catalytic subunit and glutamate-cysteine ligase modulatory subunit were detected by western blot. Our results showed that 5-HMF treatment significantly ameliorated neurological deficits, reduced brain water content, attenuated striatum neuronal damage, decreased the carbonyl groups and MDA levels, and activated Nrf2/ARE signaling pathway. Taken together, these results demonstrated that

  1. Gremlin inhibits UV-induced skin cell damages via activating VEGFR2-Nrf2 signaling

    PubMed Central

    Xu, Qiu-yun; Zhang, Jing; Lin, Meng-ting; Tu, Ying; He, Li; Bi, Zhi-gang; Cheng, Bo

    2016-01-01

    Ultra Violet (UV) radiation induces reactive oxygen species (ROS) production, DNA oxidation and single strand breaks (SSBs), which will eventually lead to skin cell damages or even skin cancer. Here, we tested the potential activity of gremlin, a novel vascular endothelial growth factor (VEGF) receptor 2 (VEGFR2) agonist, against UV-induced skin cell damages. We show that gremlin activated VEGFR2 and significantly inhibited UV-induced death and apoptosis of skin keratinocytes and fibroblasts. Pharmacological inhibition or shRNA-mediated knockdown of VEGFR2 almost abolished gremlin-mediated cytoprotection against UV in the skin cells. Further studies showed that gremlin activated VEGFR2 downstream NF-E2-related factor 2 (Nrf2) signaling, which appeared required for subsequent skin cell protection. Nrf2 shRNA knockdown or S40T dominant negative mutation largely inhibited gremlin-mediated skin cell protection against UV. At last, we show that gremlin dramatically inhibited UV-induced ROS production and DNA SSB formation in skin keratinocytes and fibroblasts. We conclude that gremlin protects skin cells from UV damages via activating VEGFR2-Nrf2 signaling. Gremlin could be further tested as a novel anti-UV skin protectant. PMID:27713170

  2. Gremlin inhibits UV-induced skin cell damages via activating VEGFR2-Nrf2 signaling.

    PubMed

    Ji, Chao; Huang, Jin-Wen; Xu, Qiu-Yun; Zhang, Jing; Lin, Meng-Ting; Tu, Ying; He, Li; Bi, Zhi-Gang; Cheng, Bo

    2016-12-20

    Ultra Violet (UV) radiation induces reactive oxygen species (ROS) production, DNA oxidation and single strand breaks (SSBs), which will eventually lead to skin cell damages or even skin cancer. Here, we tested the potential activity of gremlin, a novel vascular endothelial growth factor (VEGF) receptor 2 (VEGFR2) agonist, against UV-induced skin cell damages. We show that gremlin activated VEGFR2 and significantly inhibited UV-induced death and apoptosis of skin keratinocytes and fibroblasts. Pharmacological inhibition or shRNA-mediated knockdown of VEGFR2 almost abolished gremlin-mediated cytoprotection against UV in the skin cells. Further studies showed that gremlin activated VEGFR2 downstream NF-E2-related factor 2 (Nrf2) signaling, which appeared required for subsequent skin cell protection. Nrf2 shRNA knockdown or S40T dominant negative mutation largely inhibited gremlin-mediated skin cell protection against UV. At last, we show that gremlin dramatically inhibited UV-induced ROS production and DNA SSB formation in skin keratinocytes and fibroblasts. We conclude that gremlin protects skin cells from UV damages via activating VEGFR2-Nrf2 signaling. Gremlin could be further tested as a novel anti-UV skin protectant.

  3. Regulation of hemeoxygenase-1 gene expression by Nrf2 and c-Jun in tertiary butylhydroquinone-stimulated rat primary astrocytes

    DOE Office of Scientific and Technical Information (OSTI.GOV)

    Park, Jin-Sun; Kim, Hee-Sun, E-mail: hskimp@ewha.ac.kr

    2014-05-16

    Highlights: • tBHQ increased HO-1 mRNA and protein levels in rat primary astrocytes. • tBHQ enhanced HO-1 gene transcription in an ARE-dependent manner. • tBHQ increased the nuclear translocation and DNA binding of Nrf2 and c-Jun to ARE. • Nrf2 and c-Jun are involved in the differential modulation of HO-1 expression. • Nrf2 and c-Jun regulate HO-1 expression via their coordinated interaction. - Abstract: Hemeoxygenase-1 (HO-1) is a phase II antioxidant enzyme that is primarily involved in detoxification and cytoprotection in a variety of tissues. However, the mechanism underlying HO-1 gene expression remains unclear. In the present study, we investigatedmore » the regulation of HO-1 expression in primary cultured astrocytes by using the natural antioxidant compound tertiary butylhydroquinone (tBHQ). We found that tBHQ increased HO-1 mRNA and protein levels. Promoter analysis revealed that tBHQ enhanced HO-1 gene transcription in an antioxidant response element (ARE)-dependent manner. In addition, tBHQ increased the nuclear translocation and DNA binding of Nrf2 and c-Jun to ARE. Small interfering RNA (siRNA) experiments demonstrated that Nrf2 and c-Jun are involved in the differential modulation of HO-1 expression. Thus, Nrf2 knockdown reduced the basal level of HO-1 expression but did not affect the fold induction by tBHQ. On the other hand, knockdown of c-Jun diminished tBHQ-mediated induction of HO-1 without affecting basal expression. The data suggest that Nrf2 generally modulates the basal expression of HO-1, while c-Jun mediates HO-1 induction in response to tBHQ. The results of co-immunoprecipitation assays demonstrated a physical interaction between Nrf2 and c-Jun in tBHQ-treated astrocytes. The results suggest that Nrf2 and c-Jun regulate HO-1 expression via their coordinated interaction in tBHQ-treated rat primary astrocytes.« less

  4. De-Differentiation Confers Multidrug Resistance Via Noncanonical PERK-Nrf2 Signaling

    PubMed Central

    Del Vecchio, Catherine A.; Feng, Yuxiong; Sokol, Ethan S.; Tillman, Erik J.; Sanduja, Sandhya; Reinhardt, Ferenc; Gupta, Piyush B.

    2014-01-01

    Malignant carcinomas that recur following therapy are typically de-differentiated and multidrug resistant (MDR). De-differentiated cancer cells acquire MDR by up-regulating reactive oxygen species (ROS)–scavenging enzymes and drug efflux pumps, but how these genes are up-regulated in response to de-differentiation is not known. Here, we examine this question by using global transcriptional profiling to identify ROS-induced genes that are already up-regulated in de-differentiated cells, even in the absence of oxidative damage. Using this approach, we found that the Nrf2 transcription factor, which is the master regulator of cellular responses to oxidative stress, is preactivated in de-differentiated cells. In de-differentiated cells, Nrf2 is not activated by oxidation but rather through a noncanonical mechanism involving its phosphorylation by the ER membrane kinase PERK. In contrast, differentiated cells require oxidative damage to activate Nrf2. Constitutive PERK-Nrf2 signaling protects de-differentiated cells from chemotherapy by reducing ROS levels and increasing drug efflux. These findings are validated in therapy-resistant basal breast cancer cell lines and animal models, where inhibition of the PERK-Nrf2 signaling axis reversed the MDR of de-differentiated cancer cells. Additionally, analysis of patient tumor datasets showed that a PERK pathway signature correlates strongly with chemotherapy resistance, tumor grade, and overall survival. Collectively, these results indicate that de-differentiated cells up-regulate MDR genes via PERK-Nrf2 signaling and suggest that targeting this pathway could sensitize drug-resistant cells to chemotherapy. PMID:25203443

  5. Inflammation and airway hyperresponsiveness after chlorine exposure are prolonged by Nrf2 deficiency in mice.

    PubMed

    Ano, Satoshi; Panariti, Alice; Allard, Benoit; O'Sullivan, Michael; McGovern, Toby K; Hamamoto, Yoichiro; Ishii, Yukio; Yamamoto, Masayuki; Powell, William S; Martin, James G

    2017-01-01

    Chlorine gas (Cl 2 ) is a potent oxidant and trigger of irritant induced asthma. We explored NF-E2-related factor 2 (Nrf2)-dependent mechanisms in the asthmatic response to Cl 2 , using Nrf2-deficient mice, buthionine sulfoximine (BSO), an inhibitor of glutathione (GSH) synthesis and sulforaphane (SFN), a phytochemical regulator of Nrf2. Airway inflammation and airway hyperresponsiveness (AHR) were assessed 24 and 48h after a 5-min nose-only exposure to 100ppm Cl 2 of Nrf2-deficient and wild type Balb/C mice treated with BSO or SFN. Animals were anesthetized, paralyzed and mechanically ventilated (FlexiVent™) and challenged with aerosolized methacholine. Bronchoalveolar lavage (BAL) was performed and lung tissues were harvested for assessment of gene expression. Cl 2 exposure induced a robust AHR and an intense neutrophilic inflammation that, although similar in Nrf2-deficient mice and wild-type mice at 24h after Cl 2 exposure, were significantly greater at 48h post exposure in Nrf2-deficient mice. Lung GSH and mRNA for Nrf2-dependent phase II enzymes (NQO-1 and GPX2) were significantly lower in Nrf2-deficient than wild-type mice after Cl 2 exposure. BSO reduced GSH levels and promoted Cl 2 -induced airway inflammation in wild-type mice, but not in Nrf2-deficient mice, whereas SFN suppressed Cl 2 -induced airway inflammation in wild-type but not in Nrf2-deficient mice. AHR was not affected by either BSO or SFN at 48h post Cl 2 exposure. Nrf2-dependent phase II enzymes play a role in the resolution of airway inflammation and AHR after Cl 2 exposure. Moderate deficiency of GSH affects the magnitude of acute inflammation but not AHR. Copyright © 2016 Elsevier Inc. All rights reserved.

  6. Cordyceps sinensis increases hypoxia tolerance by inducing heme oxygenase-1 and metallothionein via Nrf2 activation in human lung epithelial cells.

    PubMed

    Singh, Mrinalini; Tulsawani, Rajkumar; Koganti, Praveen; Chauhan, Amitabh; Manickam, Manimaran; Misra, Kshipra

    2013-01-01

    Cordyceps sinensis, an edible mushroom growing in Himalayan regions, is widely recognized in traditional system of medicine. In the present study, we report the efficacy of Cordyceps sinensis in facilitating tolerance to hypoxia using A549 cell line as a model system. Treatment with aqueous extract of Cordyceps sinensis appreciably attenuated hypoxia induced ROS generation, oxidation of lipids and proteins and maintained antioxidant status similar to that of controls via induction of antioxidant gene HO1 (heme oxygenase-1), MT (metallothionein) and Nrf2 (nuclear factor erythroid-derived 2-like 2). In contrast, lower level of NF κ B (nuclear factor kappaB) and tumor necrosis factor- α observed which might be due to higher levels of HO1, MT and transforming growth factor- β . Further, increase in HIF1 (hypoxia inducible factor-1) and its regulated genes; erythropoietin, vascular endothelial growth factor, and glucose transporter-1 was observed. Interestingly, Cordyceps sinensis treatment under normoxia did not regulate the expression HIF1, NF κ B and their regulated genes evidencing that Cordyceps sinensis per se did not have an effect on these transcription factors. Overall, Cordyceps sinensis treatment inhibited hypoxia induced oxidative stress by maintaining higher cellular Nrf2, HIF1 and lowering NF κ B levels. These findings provide a basis for possible use of Cordyceps sinensis in tolerating hypoxia.

  7. Cordyceps sinensis Increases Hypoxia Tolerance by Inducing Heme Oxygenase-1 and Metallothionein via Nrf2 Activation in Human Lung Epithelial Cells

    PubMed Central

    Manickam, Manimaran; Misra, Kshipra

    2013-01-01

    Cordyceps sinensis, an edible mushroom growing in Himalayan regions, is widely recognized in traditional system of medicine. In the present study, we report the efficacy of Cordyceps sinensis in facilitating tolerance to hypoxia using A549 cell line as a model system. Treatment with aqueous extract of Cordyceps sinensis appreciably attenuated hypoxia induced ROS generation, oxidation of lipids and proteins and maintained antioxidant status similar to that of controls via induction of antioxidant gene HO1 (heme oxygenase-1), MT (metallothionein) and Nrf2 (nuclear factor erythroid-derived 2-like 2). In contrast, lower level of NFκB (nuclear factor kappaB) and tumor necrosis factor-α observed which might be due to higher levels of HO1, MT and transforming growth factor-β. Further, increase in HIF1 (hypoxia inducible factor-1) and its regulated genes; erythropoietin, vascular endothelial growth factor, and glucose transporter-1 was observed. Interestingly, Cordyceps sinensis treatment under normoxia did not regulate the expression HIF1, NFκB and their regulated genes evidencing that Cordyceps sinensis per se did not have an effect on these transcription factors. Overall, Cordyceps sinensis treatment inhibited hypoxia induced oxidative stress by maintaining higher cellular Nrf2, HIF1 and lowering NFκB levels. These findings provide a basis for possible use of Cordyceps sinensis in tolerating hypoxia. PMID:24063008

  8. Dioscin alleviates BDL- and DMN-induced hepatic fibrosis via Sirt1/Nrf2-mediated inhibition of p38 MAPK pathway

    DOE Office of Scientific and Technical Information (OSTI.GOV)

    Gu, Lina; Tao, Xufeng; Xu, Youwei

    Oxidative stress is involved in hepatic stellate cells (HSCs) activation and extracellular matrix overproduction. We previously reported the promising effects of dioscin against CCl{sub 4}-induced liver fibrosis, but its effects and mechanisms on BDL- and DMN-induced liver fibrosis remain unknown. The results in the present study indicated that dioscin significantly inhibited HSCs activation and attenuated hepatic fibrosis in rats. Furthermore, dioscin markedly up-regulated the levels of sirtuin 1 (Sirt1), HO-1, GST, GCLC and GCLM via increasing the nuclear translocation of nuclear erythroid factor 2-related factor 2 (Nrf2), which in turn inhibited mitogen-activated protein kinase 14 (p38 MAPK) phosphorylation and reducedmore » the levels of COL1A1, COL3A1, α-SMA and fibronectin. These results were further validated by knockdown of Sirt1 and Nrf2 using siRNAs silencing, and abrogation of p38 MAPK using SB-203580 (a p38 MAPK inhibitor) in HSC-T6 and LX-2 cells. Collectively, our findings confirmed the potent effects of dioscin against liver fibrosis and also provided novel insights into the mechanisms of this compound as a candidate for the prevention of liver fibrosis in the future. - Highlights: • Dioscin showed potent effects against BDL- and DMN-induced liver fibrosis in rats. • Dioscin significantly suppressed oxidative stress. • Dioscin triggered Sirt1/Nrf2-mediated inhibition of p38 MAPK pathway. • Dioscin should be developed as a novel candidate to treat liver fibrosis.« less

  9. Chemical Tuning Enhances Both Potency Toward Nrf2 and In Vitro Therapeutic Index of Triterpenoids

    PubMed Central

    Copple, Ian M.; Shelton, Luke M.; Walsh, Joanne; Kratschmar, Denise V.; Lister, Adam; Odermatt, Alex; Goldring, Christopher E.; Dinkova-Kostova, Albena T.; Honda, Tadashi; Park, B. Kevin

    2014-01-01

    The transcription factor Nrf2 protects against a number of experimental pathologies, and is a promising therapeutic target. The clinical investigation of a potent Nrf2-inducing agent, the triterpenoid (TP) bardoxolone methyl (BARD), was recently halted due to adverse cardiovascular events in chronic kidney disease patients, although the underlying mechanisms are yet to be resolved. The majority of small molecule Nrf2 inducers are electrophilic and trigger Nrf2 accumulation via the chemical modification of its redox-sensitive repressor Keap1. Therefore, it is pertinent to question whether the therapeutic targeting of Nrf2 could be hindered in many cases by the inherent reactivity of a small molecule inducer toward unintended cellular targets, a key mechanism of drug toxicity. Using H4IIE-ARE8L hepatoma cells, we have examined the relationship between (a) Nrf2 induction potency, (b) toxicity and (c) in vitro therapeutic index (ratio of b:a) for BARD and a number of other small molecule activators of Nrf2. We show that BARD exhibits the highest potency toward Nrf2 and the largest in vitro therapeutic index among compounds that have been investigated clinically (namely BARD, sulforaphane and dimethylfumarate). Through further examination of structurally related TPs, we demonstrate that an increase in potency toward Nrf2 is associated with a relatively smaller increase in toxicity, indicating that medicinal chemistry can be used to enhance the specificity of a compound as an inducer of Nrf2 signaling whilst simultaneously increasing its therapeutic index. These findings will inform the continuing design and development of drugs targeting Nrf2. PMID:24798383

  10. Long-term Autophagy and Nrf2 Signaling in the Hippocampi of Developing Mice after Carbon Ion Exposure

    PubMed Central

    Ye, Fei; Zhao, Ting; Liu, Xiongxiong; Jin, Xiaodong; Liu, Xinguo; Wang, Tieshan; Li, Qiang

    2015-01-01

    To explore charged particle radiation-induced long-term hippocampus damage, we investigated the expression of autophagy and antioxidant Nrf2 signaling-related proteins in the mouse hippocampus after carbon ion radiation. Heads of immature female Balb/c mice were irradiated with carbon ions of different LETs at various doses. Behavioral tests were performed on the mice after maturation. Acute and chronic expression of LC3-II, p62/SQSTM1, nuclear Nrf2, activated caspase-3 and the Bax/Bcl-2 ratio were measured in the hippocampi. Secondary X-ray insult was adopted to amplify potential damages. Long-term behavioral changes were observed in high-LET carbon ion-irradiated mice. There were no differences in the rates of LC3-II induction and p62/SQSTM1 degradation compared to the control group regardless of whether the mice received the secondary X-ray insult. A high nuclear Nrf2 content and low apoptosis level in hippocampal cells subjected to secondary X-rays were observed for the mice exposed to relatively low-LET carbon ions. Therefore, carbon ion exposure in the immature mouse led to an LET-dependent behavioral change after maturation. Although autophagy was intact, the persistently high nuclear Nrf2 content in the hippocampus might account for the unchanged behavioral pattern in mice exposed to the relatively low-LET carbon ions and the subsequent increased radioresistance of the hippocampus. PMID:26689155

  11. The emerging role of redox-sensitive Nrf2-Keap1 pathway in diabetes.

    PubMed

    Bhakkiyalakshmi, Elango; Sireesh, Dornadula; Rajaguru, Palanisamy; Paulmurugan, Ramasamy; Ramkumar, Kunka Mohanram

    2015-01-01

    The pathogenic processes involving in the development of diabetes range from autoimmune destruction of pancreatic β-cells with consequent insulin deficiency to abnormalities that result in resistance to insulin action. The major contributing factor for excessive β-cell death includes oxidative stress-mediated mitochondrial damage, which creates an imbalance in redox homeostasis. Yet, β-cells have evolved adaptive mechanisms to endure a wide range of stress conditions to safeguard its potential functions. These include 'Nrf2/Keap1' pathway, a key cellular defense mechanism, to combat oxidative stress by regulating phase II detoxifying and antioxidant genes. During diabetes, redox imbalance provokes defective Nrf2-dependent signaling and compromise antioxidant capacity of the pancreas which turnout β-cells to become highly vulnerable against various insults. Hence, identification of small molecule activators of Nrf2/Keap1 pathway remains significant to enhance cellular defense to overcome the burden of oxidative stress related disturbances. This review summarizes the molecular mechanism behind Nrf2 activation and the impact of Nrf2 activators in diabetes and its complications. Copyright © 2014 Elsevier Ltd. All rights reserved.

  12. Schisandra chinensis regulates drug metabolizing enzymes and drug transporters via activation of Nrf2-mediated signaling pathway

    PubMed Central

    He, Jin-Lian; Zhou, Zhi-Wei; Yin, Juan-Juan; He, Chang-Qiang; Zhou, Shu-Feng; Yu, Yang

    2015-01-01

    Drug metabolizing enzymes (DMEs) and drug transporters are regulated via epigenetic, transcriptional, posttranscriptional, and translational and posttranslational modifications. Phase I and II DMEs and drug transporters play an important role in the disposition and detoxification of a large number of endogenous and exogenous compounds. The nuclear factor (erythroid-derived 2)-like 2 (Nrf2) is a critical regulator of a variety of important cytoprotective genes that are involved in disposition and detoxification of xenobiotics. Schisandra chinensis (SC) is a commonly used traditional Chinese herbal medicine that has been primarily used to protect the liver because of its potent antioxidative and anti-inflammatory activities. SC can modulate some DMEs and drug transporters, but the underlying mechanisms are unclear. In this study, we aimed to explore the role of Nrf2 in the regulatory effect of SC extract (SCE) on selected DMEs and drug transporters in human hepatocellular liver carcinoma cell line (HepG2) cells. The results showed that SCE, schisandrin A, and schisandrin B significantly increased the expression of NAD(P)H: Nicotinamide Adenine Dinucleotide Phosphate-oxidase or:quinone oxidoreductase 1, heme oxygenase-1, glutamate–cysteine ligase, and glutathione S-transferase A4 at both transcriptional and posttranscriptional levels. Incubation of HepG2 cells with SCE resulted in a significant increase in the intracellular level of glutathione and total glutathione S-transferase content. SCE significantly elevated the messenger ribonucleic acid and protein levels of P-glycoprotein and multidrug resistance-associated protein 2 and 4, whereas the expression of organic anion transporting peptide 1A2 and 1B1 was significantly downregulated by SCE. Knockdown of Nrf2 by small interfering ribonucleic acid attenuated the regulatory effect of SCE on these DMEs and drug transporters. SCE significantly upregulated Nrf2 and promoted the translocation of Nrf2 from cytoplasm to

  13. L-Arginine ameliorates cardiac left ventricular oxidative stress by upregulating eNOS and Nrf2 target genes in alloxan-induced hyperglycemic rats

    DOE Office of Scientific and Technical Information (OSTI.GOV)

    Ramprasath, Tharmarajan; Hamenth Kumar, Palani; Syed Mohamed Puhari, Shanavas

    2012-11-23

    Highlights: Black-Right-Pointing-Pointer L-Arginine treatment reduced the metabolic disturbances in diabetic animals. Black-Right-Pointing-Pointer Antioxidant marker proteins were found high in myocardium by L-arginine treatment. Black-Right-Pointing-Pointer Elevated antioxidant status, mediates the reduced TBA-reactivity in left ventricle. Black-Right-Pointing-Pointer L-Arginine treatment enhanced the Nrf2 and eNOS signaling in left ventricle. Black-Right-Pointing-Pointer Improved cell survival signaling by arginine, offers a novel tactic for targeting. -- Abstract: Hyperglycemia is independently related with excessive morbidity and mortality in cardiovascular disorders. L-Arginine-nitric oxide (NO) pathway and the involvement of NO in modulating nuclear factor-E2-related factor-2 (Nrf2) signaling were well established. In the present study we investigated, whether L-argininemore » supplementation would improve the myocardial antioxidant defense under hyperglycemia through activation of Nrf2 signaling. Diabetes was induced by alloxan monohydrate (90 mg kg{sup -1} body weight) in rats. Both non-diabetic and diabetic group of rats were divided into three subgroups and they were administered either with L-arginine (2.25%) or L-NAME (0.01%) in drinking water for 12 days. Results showed that L-arginine treatment reduced the metabolic disturbances in diabetic rats. Antioxidant enzymes and glutathione levels were found to be increased in heart left ventricles, thereby reduction of lipid peroxidation by L-arginine treatment. Heart histopathological analysis further validates the reversal of typical diabetic characteristics consisting of alterations in myofibers and myofibrillary degeneration. qRT-PCR studies revealed that L-arginine treatment upregulated the transcription of Akt and downregulated NF-{kappa}B. Notably, transcription of eNOS and Nrf2 target genes was also upregulated, which were accompanied by enhanced expression of Nrf2 in left ventricular tissue from

  14. Lack of Effect of Oral Sulforaphane Administration on Nrf2 Expression in COPD: A Randomized, Double-Blind, Placebo Controlled Trial

    PubMed Central

    2016-01-01

    Background COPD patients have high pulmonary and systemic oxidative stress that correlates with severity of disease. Sulforaphane has been shown to induce expression of antioxidant genes via activation of a transcription factor, nuclear factor erythroid-2 related factor 2 (Nrf2). Methods This parallel, placebo-controlled, phase 2, randomized trial was conducted at three US academic medical centers. Patients who met GOLD criteria for COPD and were able to tolerate bronchoscopies were randomly assigned (1:1:1) to receive placebo, 25 μmoles, or 150 μmoles sulforaphane daily by mouth for four weeks. The primary outcomes were changes in Nrf2 target gene expression (NQ01, HO1, AKR1C1 and AKR1C3) in alveolar macrophages and bronchial epithelial cells. Secondary outcomes included measures of oxidative stress and airway inflammation, and pulmonary function tests. Results Between July 2011 and May 2013, 89 patients were enrolled and randomized. Sulforaphane was absorbed in the patients as evident from their plasma metabolite levels. Changes in Nrf2 target gene expression relative to baseline ranged from 0.79 to 1.45 and there was no consistent pattern among the three groups; the changes were not statistically significantly different from baseline. Changes in measures of inflammation and pulmonary function tests were not different among the groups. Sulforaphane was well tolerated at both dose levels. Conclusion Sulforaphane administered for four weeks at doses of 25 μmoles and 150 μmoles to patients with COPD did not stimulate the expression of Nrf2 target genes or have an effect on levels of other anti-oxidants or markers of inflammation. Trial Registration Clinicaltrials.gov: NCT01335971. PMID:27832073

  15. Lack of Effect of Oral Sulforaphane Administration on Nrf2 Expression in COPD: A Randomized, Double-Blind, Placebo Controlled Trial.

    PubMed

    Wise, Robert A; Holbrook, Janet T; Criner, Gerard; Sethi, Sanjay; Rayapudi, Sobharani; Sudini, Kuladeep R; Sugar, Elizabeth A; Burke, Alyce; Thimmulappa, Rajesh; Singh, Anju; Talalay, Paul; Fahey, Jed W; Berenson, Charles S; Jacobs, Michael R; Biswal, Shyam

    2016-01-01

    COPD patients have high pulmonary and systemic oxidative stress that correlates with severity of disease. Sulforaphane has been shown to induce expression of antioxidant genes via activation of a transcription factor, nuclear factor erythroid-2 related factor 2 (Nrf2). This parallel, placebo-controlled, phase 2, randomized trial was conducted at three US academic medical centers. Patients who met GOLD criteria for COPD and were able to tolerate bronchoscopies were randomly assigned (1:1:1) to receive placebo, 25 μmoles, or 150 μmoles sulforaphane daily by mouth for four weeks. The primary outcomes were changes in Nrf2 target gene expression (NQ01, HO1, AKR1C1 and AKR1C3) in alveolar macrophages and bronchial epithelial cells. Secondary outcomes included measures of oxidative stress and airway inflammation, and pulmonary function tests. Between July 2011 and May 2013, 89 patients were enrolled and randomized. Sulforaphane was absorbed in the patients as evident from their plasma metabolite levels. Changes in Nrf2 target gene expression relative to baseline ranged from 0.79 to 1.45 and there was no consistent pattern among the three groups; the changes were not statistically significantly different from baseline. Changes in measures of inflammation and pulmonary function tests were not different among the groups. Sulforaphane was well tolerated at both dose levels. Sulforaphane administered for four weeks at doses of 25 μmoles and 150 μmoles to patients with COPD did not stimulate the expression of Nrf2 target genes or have an effect on levels of other anti-oxidants or markers of inflammation. Clinicaltrials.gov: NCT01335971.

  16. Repeated Nrf2 stimulation using sulforaphane protects fibroblasts from ionizing radiation

    DOE Office of Scientific and Technical Information (OSTI.GOV)

    Mathew, Sherin T.; Bergström, Petra; Hammarsten, Ola, E-mail: ola.hammarsten@clinchem.gu.se

    2014-05-01

    Most of the cytotoxicity induced by ionizing radiation is mediated by radical-induced DNA double-strand breaks. Cellular protection from free radicals can be stimulated several fold by sulforaphane-mediated activation of the transcription factor Nrf2 that regulates more than 50 genes involved in the detoxification of reactive substances and radicals. Here, we report that repeated sulforaphane treatment increases radioresistance in primary human skin fibroblasts. Cells were either treated with sulforaphane for four hours once or with four-hour treatments repeatedly for three consecutive days prior to radiation exposure. Fibroblasts exposed to repeated-sulforaphane treatment showed a more pronounced dose-dependent induction of Nrf2-regulated mRNA andmore » reduced amount of radiation-induced free radicals compared with cells treated once with sulforaphane. In addition, radiation- induced DNA double-strand breaks measured by gamma-H2AX foci were attenuated following repeated sulforaphane treatment. As a result, cellular protection from ionizing radiation measured by the 5-ethynyl-2′-deoxyuridine (EdU) assay was increased, specifically in cells exposed to repeated sulforaphane treatment. Sulforaphane treatment was unable to protect Nrf2 knockout mouse embryonic fibroblasts, indicating that the sulforaphane-induced radioprotection was Nrf2-dependent. Moreover, radioprotection by repeated sulforaphane treatment was dose-dependent with an optimal effect at 10 uM, whereas both lower and higher concentrations resulted in lower levels of radioprotection. Our data indicate that the Nrf2 system can be trained to provide further protection from radical damage. - Highlights: • Repeated treatment with sulforaphane protects fibroblasts from ionizing radiation • Repeated sulforaphane treatment attenuates radiation induced ROS and DNA damage • Sulforaphane mediated protection is Nrf2 dependent.« less

  17. Taurine protects against As2O3-induced autophagy in pancreas of rat offsprings through Nrf2/Trx pathway.

    PubMed

    Bai, Jie; Yao, Xiaofeng; Jiang, Liping; Qiu, Tianming; Liu, Shuang; Qi, Baoxu; Zheng, Yue; Kong, Yuan; Yang, Guang; Chen, Min; Liu, Xiaofang; Sun, Xiance

    2016-04-01

    Arsenic was increasingly to blame as a risk factor for type 2 diabetes mellitus. In our previous study, we had found iAs stimulated autophagic flux and caused autophagic cell death through ROS pathway in INS-1 cells. Since NF-E2-related factor 2 (Nrf2) and the thioredoxin (Trx) system was a crucial line of defense against ROS, we investigated whether Nrf2/Trx pathway contributed to As2O3-stimulated autophagy and the role of taurine in this study. After treatment with 2 mg/kg BW-8 mg/kg BW As2O3 for 57 d, the expression of Nrf2 protein was decreased significantly in offsprings' pancreas. The expression of Trx gene was decreased significantly in pancreas subsequently. Finally, the generation of reactive oxygen species stimulated autophagy in arsenic-treated pancreas. Taurine could reverse arsenic-inhibited Nrf2 and Trx and inhibit autophagy. In short, inhibition of Nrf2/Trx pathway might play an important role in the pathogenesis of arsenic-related diabetes. Taurine could serve as nutrition supplementation against arsenic-related diabetes in high arsenic exposure area. Copyright © 2016 Elsevier B.V. and Société Française de Biochimie et Biologie Moléculaire (SFBBM). All rights reserved.

  18. l-Arginine induces antioxidant response to prevent oxidative stress via stimulation of glutathione synthesis and activation of Nrf2 pathway.

    PubMed

    Liang, Mingcai; Wang, Zhengxuan; Li, Hui; Cai, Liang; Pan, Jianghao; He, Hongjuan; Wu, Qiong; Tang, Yinzhao; Ma, Jiapei; Yang, Lin

    2018-05-01

    Arginine is a conditionally essential amino acid. To elucidate the influence of l-arginine on the activation of endogenous antioxidant defence, male Wistar rats were orally administered daily with l-arginine at different levels of 25, 50, 100 mg/100 g body weight. After 7 and 14 days feeding, the antioxidative capacities and glutathione (GSH) contents in the plasma and in the liver were uniformly enhanced with the increasing consumption of l-arginine, whereas the oxidative stress was effectively suppressed by l-arginine treatment. After 14 days feeding, the mRNA levels and protein expressions of Keap1 and Cul3 were gradually reduced by increasing l-arginine intake, resulting that the nuclear factor Nrf2 was activated. Upon activation of Nrf2, the expressions of antioxidant responsive element (ARE)-dependent genes and proteins (GCLC, GCLM, GS, GR, GST, GPx, CAT, SOD, NQO1, HO-1) were up-regulated by l-arginine feeding, indicating an upward trend in antioxidant capacity uniformly with the increasing consumption of l-arginine. The present study demonstrates that the supplementation of l-arginine stimulates GSH synthesis and activates Nrf2 pathway, leading to the up-regulation of ARE-driven antioxidant expressions via Nrf2-Keap1 pathway. Results suggest the availability of l-arginine is a critical factor to suppress oxidative stress and induce an endogenous antioxidant response. Copyright © 2018 Elsevier Ltd. All rights reserved.

  19. Regulation of Cigarette Smoke (CS)-Induced Autophagy by Nrf2.

    PubMed

    Zhu, Lingxiang; Barrett, Erika C; Barret, Erika C; Xu, Yuxue; Liu, Zuguo; Manoharan, Aditya; Chen, Yin

    2013-01-01

    Cigarette smoke (CS) has been reported to induce autophagy in airway epithelial cells. The subsequent autophagic cell death has been proposed to play an important pathogenic role in chronic obstructive pulmonary disease (COPD); however, the underlying molecular mechanism is not entirely clear. Using CS extract (CSE) as a surrogate for CS, we found that it markedly increased the expressions of both LC3B-I and LC3B-II as well as autophagosomes in airway epithelial cells. This is in contrast to the common autophagy inducer (i.e., starvation) that increases LC3B-II but reduces LC3B-I. Further studies indicate that CSE regulated LC3B at transcriptional and post-translational levels. In addition, CSE, but not starvation, activated Nrf2-mediated adaptive response. Increase of cellular Nrf2 by either Nrf2 overexpression or the knockdown of Keap1 (an Nrf2 inhibitor) significantly repressed CSE-induced LC3B-I and II as well as autophagosomes. Supplement of NAC (a GSH precursor) or GSH recapitulated the effect of Nrf2, suggesting the increase of cellular GSH level is responsible for Nrf2 effect on LC3B and autophagosome. Interestingly, neither Nrf2 activation nor GSH supplement could restore the repressed activities of mTOR or its downstream effctor-S6K. Thus, the Nrf2-dependent autophagy-suppression was not due to the re-activation of mTOR-the master repressor of autophagy. To search for the downstream effector of Nrf2 on LC3B and autophagosome, we tested Nrf2-dependent genes (i.e., NQO1 and P62) that are also increased by CSE treatment. We found that P62, but not NQO1, could mimic the effect of Nrf2 activation by repressing LC3B expression. Thus, Nrf2->P62 appears to play an important role in the regulation of CSE-induced LC3B and autophagosome.

  20. Alleviation of Acute Lung Injury in Rats with Sepsis by Resveratrol via the Phosphatidylinositol 3-Kinase/Nuclear Factor-Erythroid 2 Related Factor 2/Heme Oxygenase-1 (PI3K/Nrf2/HO-1) Pathway.

    PubMed

    Wang, Yu; Wang, Xiaofeng; Zhang, Lichun; Zhang, Rong

    2018-05-30

    BACKGROUND Resveratrol (Res) is a type of polyphenol found in many plants, which can protect important organs from the damage induced by sepsis. However, the exact mechanism of its protective effect has not been established. This study investigated the effect of Res on the PI3K/Nrf2/HO-1 signaling pathway in rats with sepsis-induced acute lung injury (ALI). MATERIAL AND METHODS Male Wistar rats were treated with 30 mg/kg Res by intraperitoneal administration for 1 hour immediately after cecal ligation and puncture. Levels of MIP-2, IL-18, and IL-10 in bronchoalveolar lavage fluid (BALF) were determined. Lung tissues were collected to measure the wet-to-dry (W/D) ratios, oxidative stress index, and lung injury scores. Expression levels of Akt, p-Akt, HO-1, Nrf-2, and active caspase-3 proteins were determined by western blotting; expression of HO-1 mRNA was determined by RT-PCR. RESULTS Treatment with Res significantly decreased the levels of MIP-2 and IL-18 and increased IL-10 in the BALF of rats with sepsis-induced ALI. In addition, Res also effectively reduced the W/D lung weight ratio, lung injury score, and the levels of MDA (malondialdehyde) and 8-OHdG. Conversely, Res increased SOD (superoxide dismutase) activity in the lung tissue. Moreover, Res significantly induced higher HO-1 mRNA expression, upregulated HO-1 and Nrf-2 protein expression, and the phosphorylation of Akt in the lung tissue. In contrast, the levels of activated caspase-3 protein were decreased in Res-treated rats (P<0.05). CONCLUSIONS Res could inhibit inflammation, oxidative stress, and cell apoptosis to alleviate ALI in septic rats through the inhibition of the PI3K/Nrf2/HO-1 signaling pathway.

  1. α-Lipoic Acid Promotes Neurological Recovery After Ischemic Stroke by Activating the Nrf2/HO-1 Pathway to Attenuate Oxidative Damage.

    PubMed

    Lv, Chengmei; Maharjan, Surendra; Wang, Qingqing; Sun, Yongxin; Han, Xu; Wang, Shan; Mao, Zhengchun; Xin, Yanming; Zhang, Bing

    2017-01-01

    Alpha-lipoic acid (α-LA) has been demonstrated to be protective against cerebral ischemia injury. Herein, we investigate the neuroprotective effect and underlying mechanisms of α-LA. In vivo study, α-LA was administered intravenously upon reperfusion of transient middle cerebral artery occlusion. Garcia score was used to evaluate neurologic recovery. Infarct volume was examined by TTC staining, and oxidative damage was evaluated by ELISA assay. In an in vitro study, neurons were pretreated with α-LA at different doses and then subjected to OGD. Lentiviral vectors were applied to knockdown nuclear factor-erythroid 2-related factor-2 (Nrf2) or heme oxygenase-1 (HO-1). Cell viability was measured using CCK8. Protein expression was evaluated using western blot, and immunofluorescence staining was assessed. α-LA significantly reduced the infarct volume, brain edema, and oxidative damage and promoted neurologic recovery in rats. Pretreatment of α-LA caused an obvious increase in cell viability and a decrease in intracellular reactive oxygen species. Western blot analyses and immunofluorescence staining demonstrated a distinct increase in Nrf2 and HO-1 protein expression. Conversely, knockdown of Nrf2 or HO-1 resulted in the down-regulation of HO-1 protein and inhibited the neuroprotective effect of α-LA. α-LA treatment is neuroprotective and promotes functional recovery after ischemic stroke by attenuating oxidative damage, which is partially mediated by the Nrf2/HO-1 pathway. © 2017 The Author(s). Published by S. Karger AG, Basel.

  2. Molecular pathology of cerebral TNF-α, IL-1β, iNOS and Nrf2 in forensic autopsy cases with special regard to deaths due to environmental hazards and intoxication.

    PubMed

    Du, Si-Hao; Tan, Xiao-Hui; Zhao, Rui; Zhao, Dong; Xue, Ye; Wang, Hui-Jun; Xie, Xiao-Li; Wang, Qi

    2017-12-01

    Deaths involved with environmental hazards and intoxication might present with minimal or nonspecific morphological features, which are insufficient to establish a diagnosis. The present study investigated the postmortem brain mRNA and immunohistochemical expressions of tumor necrosis factor-α (TNF-α), interleukin-1β (IL-1β), inducible nitric oxide synthase (iNOS) and nuclear factor erythroid-2-related factor-2 (Nrf2) in forensic cases. Relative mRNA quantification using Taqman real-time PCR assay demonstrated higher expression of IL-1β, TNF-α and iNOS, and lower expression of Nrf2 in methamphetamine intoxication and hyperthermia cases, higher expression of iNOS in phenobarbital intoxication cases, and higher expression of Nrf2 in phenobarbital intoxication and hypothermia cases. Immunostaining results showed substantial inter-individual variations in each group, showing no evident differences in distribution or intensity. These findings suggest that different inflammatory and antioxidant responses were involved in deaths from different etiologies, and these markers may be useful for evaluating brain damage and responses.

  3. Early Induction of NRF2 Antioxidant Pathway by RHBDF2 Mediates Rapid Cutaneous Wound Healing

    PubMed Central

    Hosur, Vishnu; Burzenski, Lisa M.; Stearns, Timothy M.; Farley, Michelle L.; Sundberg, John P.; Wiles, Michael V.; Shultz, Leonard D.

    2017-01-01

    Rhomboid family protein RHBDF2, an upstream regulator of the epidermal growth factor (EGF) receptor signaling, has been implicated in cutaneous wound healing. However, the underlying molecular mechanisms are still emerging. In humans, a gain-of-function mutation in the RHBDF2 gene accelerates cutaneous wound healing in an EGFR-dependent manner. Likewise, a gain-of-function mutation in the mouse Rhbdf2 gene (Rhbdf2cub/cub) shows a regenerative phenotype (rapid ear-hole closure) resulting from constitutive activation of the EGFR pathway. Because the RHBDF2-regulated EGFR pathway is relevant to cutaneous wound healing in humans, we used Rhbdf2cub/cub mice to investigate the biological networks and pathways leading to accelerated ear-hole closure, with the goal of identifying therapeutic targets potentially effective in promoting wound healing in humans. Comparative transcriptome analysis of ear pinna tissue from Rhbdf2cub/cub and Rhbdf2+/+ mice at 0h, 15 min, 2h, and 24h post-wounding revealed an early induction of the nuclear factor E2-related factor 2 (NRF2)-mediated anti-oxidative pathway (0h and 15 min), followed by the integrin-receptor aggregation pathway (2h) as early-stage events immediately and shortly after wounding in Rhbdf2cub/cub mice. Additionally, we observed genes enriched for the Fc fragment of the IgG receptor IIIa (FCGR3A)-mediated phagocytosis pathway 24h post-wounding. Although cutaneous wound repair in healthy individuals is generally non-problematic, it can be severely impaired due to aging, diabetes, and chronic inflammation. This study suggests that activation of the NRF2-antioxidant pathway by rhomboid protein RHBDF2 might be beneficial in treating chronic non-healing wounds. PMID:28268192

  4. Early induction of NRF2 antioxidant pathway by RHBDF2 mediates rapid cutaneous wound healing.

    PubMed

    Hosur, Vishnu; Burzenski, Lisa M; Stearns, Timothy M; Farley, Michelle L; Sundberg, John P; Wiles, Michael V; Shultz, Leonard D

    2017-04-01

    Rhomboid family protein RHBDF2, an upstream regulator of the epidermal growth factor (EGF) receptor signaling, has been implicated in cutaneous wound healing. However, the underlying molecular mechanisms are still emerging. In humans, a gain-of-function mutation in the RHBDF2 gene accelerates cutaneous wound healing in an EGFR-dependent manner. Likewise, a gain-of-function mutation in the mouse Rhbdf2 gene (Rhbdf2 cub/cub ) shows a regenerative phenotype (rapid ear-hole closure) resulting from constitutive activation of the EGFR pathway. Because the RHBDF2-regulated EGFR pathway is relevant to cutaneous wound healing in humans, we used Rhbdf2 cub/cub mice to investigate the biological networks and pathways leading to accelerated ear-hole closure, with the goal of identifying therapeutic targets potentially effective in promoting wound healing in humans. Comparative transcriptome analysis of ear pinna tissue from Rhbdf2 cub/cub and Rhbdf2 +/+ mice at 0h, 15min, 2h, and 24h post-wounding revealed an early induction of the nuclear factor E2-related factor 2 (NRF2)-mediated anti-oxidative pathway (0h and 15min), followed by the integrin-receptor aggregation pathway (2h) as early-stage events immediately and shortly after wounding in Rhbdf2 cub/cub mice. Additionally, we observed genes enriched for the Fc fragment of the IgG receptor IIIa (FCGR3A)-mediated phagocytosis pathway 24h post-wounding. Although cutaneous wound repair in healthy individuals is generally non-problematic, it can be severely impaired due to aging, diabetes, and chronic inflammation. This study suggests that activation of the NRF2-antioxidant pathway by rhomboid protein RHBDF2 might be beneficial in treating chronic non-healing wounds. Copyright © 2017 Elsevier Inc. All rights reserved.

  5. Simvastatin Treatment Upregulates HO-1 in Patients with Abdominal Aortic Aneurysm but Independently of Nrf2

    PubMed Central

    Kopacz, Aleksandra; Kloska, Damian; Zagrapan, Branislav; Neumayer, Christoph; Grochot-Przeczek, Anna; Huk, Ihor; Brostjan, Christine; Dulak, Jozef

    2018-01-01

    Heme oxygenase-1 (HO-1), encoded by HMOX1 gene and regulated by Nrf2 transcription factor, is a cytoprotective enzyme. Its deficiency may exacerbate abdominal aortic aneurysm (AAA) development, which is also often associated with hyperlipidemia. Beneficial effects of statins, the broadly used antilipidemic drugs, were attributed to modulation of Nrf2/HO-1 axis. However, the effect of statins on Nrf2/HO-1 pathway in patients with AAA has not been studied yet. We analyzed AAA tissue from patients treated with simvastatin (N = 28) or without statins (N = 14). Simvastatin treatment increased HO-1 protein level in AAA, both in endothelial cells (ECs) and in smooth muscle cells (SMCs), but increased Nrf2 localization was restricted only to vasa vasorum. Nrf2 target genes HMOX1, NQO1, and GCLM expression remained unchanged in AAA. In vitro studies showed that simvastatin raises HO-1 protein level slightly in ECs and to much higher extent in SMCs, which is not related to Nrf2/ARE activation, although HMOX1 expression is upregulated by simvastatin in both cell types. In conclusion, simvastatin-induced modulation of HO-1 level in ECs and SMCs in vitro is not related to Nrf2/ARE activity. Likewise, divergent HO-1 and Nrf2 localization together with stable expression of Nrf2 target genes, including HMOX1, in AAA tissue denotes Nrf2 independency. PMID:29743974

  6. Role of bardoxolone methyl, a nuclear factor erythroid 2-related factor 2 activator, in aldosterone- and salt-induced renal injury.

    PubMed

    Hisamichi, Mikako; Kamijo-Ikemori, Atsuko; Sugaya, Takeshi; Hoshino, Seiko; Kimura, Kenjiro; Shibagaki, Yugo

    2018-01-01

    The aim of this study was to investigate the renoprotective effect of bardoxolone methyl (BM), a nuclear factor erythroid 2-related factor 2 (Nrf2) activator with an antioxidant effect, in a salt-sensitive hypertension model induced by aldosterone (Ald) and salt. Tubulointerstitial damage with urinary liver-type fatty acid-binding protein (L-FABP) was evaluated using human L-FABP chromosomal transgenic (L-FABP +/- ) male mice. The mice in the Ald group (n=7) received systemic Ald infusions via an osmotic minipump and were given 1% NaCl water for 35 days. Those in the Ald-BM group (n=8) were administered BM intraperitoneally in addition to an injection of Ald and salt. The dose of BM was gradually increased every 7 days up to 10 mg kg -1 per day, which was maintained for 14 days. The administration of BM significantly increased renal expression of the Nrf2 target antioxidant gene. Tubulointerstitial damage was significantly ameliorated in the Ald-BM group compared to the Ald group. The increase in reactive oxygen species (ROS) and upregulation of angiotensinogen expression in the kidneys of the Ald group was significantly prevented in the Ald-BM group. The upregulation of human L-FABP expression induced in the kidneys and increase in urinary L-FABP in the Ald group were significantly suppressed by BM administration. In conclusion, BM ameliorated tubulointerstitial damage in the Ald- and salt-induced hypertension model through suppression of both ROS production and intrarenal renin-angiotensin system activation. Urinary L-FABP may be a useful marker reflecting the therapeutic efficacy of BM.

  7. Inhibition of microRNA-153 protects neurons against ischemia/reperfusion injury in an oxygen-glucose deprivation and reoxygenation cellular model by regulating Nrf2/HO-1 signaling.

    PubMed

    Ji, Qiong; Gao, Jianbo; Zheng, Yan; Liu, Xueli; Zhou, Qiangqiang; Shi, Canxia; Yao, Meng; Chen, Xia

    2017-07-01

    MicroRNAs are emerging as critical regulators in cerebral ischemia/reperfusion injury; however, their exact roles remain poorly understood. miR-153 is reported to be a neuron-related miRNA involved in neuroprotection. In this study, we aimed to investigate the precise role of miR-153 in regulating neuron survival during cerebral ischemia/reperfusion injury using an oxygen-glucose deprivation and reoxygenation (OGD/R) cellular model. We found that miR-153 was significantly upregulated in neurons subjected to OGD/R treatment. Inhibition of miR-153 significantly attenuated OGD/R-induced injury and oxidative stress in neurons. Nuclear factor erythroid 2-related factor 2 (Nrf2) was identified as a target gene of miR-153. Inhibition of miR-153 significantly promoted the expression of Nrf2 and heme oxygenase-1 (HO-1). However, silencing of Nrf2 significantly blocked the protective effects of miR-153 inhibition. Our study indicates that the inhibition of miR-153 protects neurons against OGD/R-induced injury by regulating Nrf2/HO-1 signaling and suggests a potential therapeutic target for cerebral ischemia/reperfusion injury. © 2017 Wiley Periodicals, Inc.

  8. Nrf2-dependent induction of innate host defense via heme oxygenase-1 inhibits Zika virus replication

    DOE Office of Scientific and Technical Information (OSTI.GOV)

    Huang, Hanxia; Falgout, Barry; Takeda, Kazuyo

    We identified primary human monocyte-derived macrophages (MDM) as vulnerable target cells for Zika virus (ZIKV) infection. We demonstrate dramatic effects of hemin, the natural inducer of the heme catabolic enzyme heme oxygenase-1 (HO-1), in the reduction of ZIKV replication in vitro. Both LLC-MK2 monkey kidney cells and primary MDM exhibited hemin-induced HO-1 expression with major reductions of >90% in ZIKV replication, with little toxicity to infected cells. Silencing expression of HO-1 or its upstream regulatory gene, nuclear factor erythroid-related factor 2 (Nrf2), attenuated hemin-induced suppression of ZIKV infection, suggesting an important role for induction of these intracellular mediators in retardingmore » ZIKV replication. The inverse correlation between hemin-induced HO-1 levels and ZIKV replication provides a potentially useful therapeutic modality based on stimulation of an innate cellular response against Zika virus infection. - Highlights: •Hemin treatment protected monocyte-derived macrophages against Zika virus (ZIKV) infection. •Innate cellular protection against ZIKV infection correlated with Nrf2-dependent HO-1 expression. •Stimulation of innate cellular responses may provide a therapeutic strategy against ZIKV infection.« less

  9. Sulforaphane reduction of testicular apoptotic cell death in diabetic mice is associated with the upregulation of Nrf2 expression and function.

    PubMed

    Wang, Yonggang; Zhang, Zhiguo; Guo, Weiying; Sun, Weixia; Miao, Xiao; Wu, Hao; Cong, Xianling; Wintergerst, Kupper A; Kong, Xiangbo; Cai, Lu

    2014-07-01

    Diabetes-induced testicular cell death is due predominantly to oxidative stress. Nuclear factor (erythroid-derived 2)-like 2 (Nrf2) is an important transcription factor in controlling the antioxidative system and is inducible by sulforaphane (SFN). To test whether SFN prevents diabetes-induced testicular cell death, an insulin-defective stage of type 2 diabetes (IDS-T2DM) was induced in mice. This was accomplished by feeding them a high-fat diet (HFD) for 3 mo to induce insulin resistance and then giving one intraperitoneal injection of streptozotocin to induce hyperglycemia while age-matched control mice were fed a normal diet (ND). IDS-T2DM and ND-fed control mice were then further subdivided into those with or without 4-mo SFN treatment. IDS-T2DM induced significant increases in testicular cell death presumably through receptor and mitochondrial pathways, shown by increased ratio of Bax/Bcl2 expression and cleavage of caspase-3 and caspase-8 without significant change of endoplasmic reticulum stress. Diabetes also significantly increased testicular oxidative damage and inflammation. All of these diabetic effects were significantly prevented by SFN treatment with upregulated Nrf2 expression. These results suggest that IDS-T2DM induces testicular cell death presumably through caspase-8 activation and mitochondria-mediated cell death pathways and also by significantly downregulating testicular Nrf2 expression and function. SFN upregulates testicular Nrf2 expression and its target antioxidant expression, which was associated with significant protection of the testis from IDS-T2DM-induced germ cell death. Copyright © 2014 the American Physiological Society.

  10. Elucidation of the therapeutic role of mitochondrial biogenesis transducers NRF-1 in the regulation of renal fibrosis

    DOE Office of Scientific and Technical Information (OSTI.GOV)

    Hsieh, Pei-Fang; Graduate Institute of Medical Laboratory Science and Biotechnology, Chung Hwa University of Medical Technology, Tainan, Taiwan; Liu, Shu-Fen

    Background: Mitochondrial dysfunction is a newly established risk factor for the development of renal fibrosis. Cell survival and injury repair is facilitated by mitochondrial biogenesis. Nuclear respiratory factor 1 (NRF-1) is a transcriptional regulation factor that plays a central role in the regulation of mitochondrial biogenesis. However, the transcription factor of this process in renal fibrosis is unknown. Thus, we hereby discussed the correlations of NRF-1 and renal interstitial fibrosis. Materials and methods: In vitro fibrosis model was established by treatment with transforming growth factor-β1 (TGF-β1) in NRK-49F (Normal Rat kidney fibroblast). We investigated the ROS production, mitochondrial biogenesis andmore » fibrogenic marker (e.q. fibronectin) during the progression of renal fibrosis by kit and Western blotting assay. Here, we used that two distinct mechanisms regulate NRF-1 activation and degradation of NRF-1. NRF-1 was transfect by pcDNA-NRF-1 overexpression gene to evaluate the NRF-1 activity of the therapeutic effect in renal fibrosis. In addition, NRF-1 was silenced by shRNA-NRF-1 to evaluate the significance of NRF-1. ELISA was used to evaluate the secreted fibronectin. Immunofluorescence staining was used to assay the in situ expression of proteins (e.g. fibronectin, NRF-1). Results: Under renal fibrosis conditions, TGF-β1 (5 ng/ml) increased ROS. Simultaneously, TGF-β1-induced extracellular fibronectin by ELISA assay. In addition, TGF-β1 decreased expression of mitochondrial biogenesis. This is the first time to demonstrate that expression of NRF-1 is significantly decreased in renal fibrosis. However, NRK49F was a transfection with pcDNA-NRF-1 (2 μg/ml) expression vector dramatically reverse TGF-β1-induced cellular fibrosis concomitantly with the suppression of fibronectin (both intracellular and extracellular fibronectin). More importantly, transfection with shRNA-NRF-1 (2 μg/ml) significantly increased the expression of

  11. Elucidation of the therapeutic role of mitochondrial biogenesis transducers NRF-1 in the regulation of renal fibrosis.

    PubMed

    Hsieh, Pei-Fang; Liu, Shu-Fen; Hung, Tsung-Jen; Hung, Chien-Ya; Liu, Guo-Zheng; Chuang, Lea-Yea; Chen, Mei-Fen; Wang, Jue-Long; Shi, Ming-Der; Hsu, Chen Hung; Shiue, Yow-Ling; Yang, Yu-Lin

    2016-11-15

    Mitochondrial dysfunction is a newly established risk factor for the development of renal fibrosis. Cell survival and injury repair is facilitated by mitochondrial biogenesis. Nuclear respiratory factor 1 (NRF-1) is a transcriptional regulation factor that plays a central role in the regulation of mitochondrial biogenesis. However, the transcription factor of this process in renal fibrosis is unknown. Thus, we hereby discussed the correlations of NRF-1 and renal interstitial fibrosis. In vitro fibrosis model was established by treatment with transforming growth factor-β1 (TGF-β1) in NRK-49F (Normal Rat kidney fibroblast). We investigated the ROS production, mitochondrial biogenesis and fibrogenic marker (e.q. fibronectin) during the progression of renal fibrosis by kit and Western blotting assay. Here, we used that two distinct mechanisms regulate NRF-1 activation and degradation of NRF-1. NRF-1 was transfect by pcDNA-NRF-1 overexpression gene to evaluate the NRF-1 activity of the therapeutic effect in renal fibrosis. In addition, NRF-1 was silenced by shRNA-NRF-1 to evaluate the significance of NRF-1. ELISA was used to evaluate the secreted fibronectin. Immunofluorescence staining was used to assay the in situ expression of proteins (e.g. fibronectin, NRF-1). Under renal fibrosis conditions, TGF-β1 (5ng/ml) increased ROS. Simultaneously, TGF-β1-induced extracellular fibronectin by ELISA assay. In addition, TGF-β1 decreased expression of mitochondrial biogenesis. This is the first time to demonstrate that expression of NRF-1 is significantly decreased in renal fibrosis. However, NRK49F was a transfection with pcDNA-NRF-1 (2μg/ml) expression vector dramatically reverse TGF-β1-induced cellular fibrosis concomitantly with the suppression of fibronectin (both intracellular and extracellular fibronectin). More importantly, transfection with shRNA-NRF-1 (2μg/ml) significantly increased the expression of fibronectin of both intercellular and extracellular origins

  12. Induction of cancer chemopreventive enzymes by coffee is mediated by transcription factor Nrf2. Evidence that the coffee-specific diterpenes cafestol and kahweol confer protection against acrolein

    DOE Office of Scientific and Technical Information (OSTI.GOV)

    Higgins, Larry G.; Cavin, Christophe; Itoh, Ken

    2008-02-01

    Mice fed diets containing 3% or 6% coffee for 5 days had increased levels of mRNA for NAD(P)H:quinone oxidoreductase 1 (NQO1) and glutathione S-transferase class Alpha 1 (GSTA1) of between 4- and 20-fold in the liver and small intestine. Mice fed 6% coffee also had increased amounts of mRNA for UDP-glucuronosyl transferase 1A6 (UGT1A6) and the glutamate cysteine ligase catalytic (GCLC) subunit of between 3- and 10-fold in the small intestine. Up-regulation of these mRNAs was significantly greater in mice possessing Nrf2 (NF-E2 p45 subunit-related factor 2) than those lacking the transcription factor. Basal levels of mRNAs for NQO1, GSTA1,more » UGT1A6 and GCLC were lower in tissues from nrf2{sup -/-} mice than from nrf2{sup +/+} mice, but modest induction occurred in the mutant animals. Treatment of mouse embryonic fibroblasts (MEFs) from nrf2{sup +/+} mice with either coffee or the coffee-specific diterpenes cafestol and kahweol (C + K) increased NQO1 mRNA up to 9-fold. MEFs from nrf2{sup -/-} mice expressed less NQO1 mRNA than did wild-type MEFs, but NQO1 was induced modestly by coffee or C + K in the mutant fibroblasts. Transfection of MEFs with nqo1-luciferase reporter constructs showed that induction by C + K was mediated primarily by Nrf2 and required the presence of an antioxidant response element in the 5'-upstream region of the gene. Luciferase reporter activity did not increase following treatment of MEFs with 100 {mu}mol/l furan, suggesting that this ring structure within C + K is insufficient for gene induction. Priming of nrf2{sup +/+} MEFs, but not nrf2{sup -/-} MEFs, with C + K conferred 2-fold resistance towards acrolein.« less

  13. Licochalcone E activates Nrf2/antioxidant response element signaling pathway in both neuronal and microglial cells: therapeutic relevance to neurodegenerative disease.

    PubMed

    Kim, Sa Suk; Lim, Juhee; Bang, Yeojin; Gal, Jiyeong; Lee, Sang-Uk; Cho, Young-Chang; Yoon, Goo; Kang, Bok Yun; Cheon, Seung Hoon; Choi, Hyun Jin

    2012-10-01

    Oxidative stress and neuroinflammation are hallmarks of neurodegenerative diseases, which do not play independently but work synergistically through complex interactions exacerbating neurodegeneration. Therefore, the mechanism that is directly implicated in controlling oxidative stress and inflammatory response could be an attractive strategy to prevent the onset and/or delay the progression of neurodegenerative diseases. The transcription factor nuclear factor-E2-related factor-2 (Nrf2) is the guardian of redox homeostasis by regulating a battery of antioxidant and phase II detoxification genes, which are relevant to defense mechanism against oxidative stress and inflammatory responses. In this study, we show that a recently identified Glycyrrhiza-inflata-derived chalcone, licochalcone E (Lico-E), attenuates lipopolysaccharide-induced inflammatory responses in microglial BV2 cells and protects dopaminergic SH-SY5Y cells from 6-hydroxydopamine cytotoxicity. Lico-E activates Nrf2-antioxidant response element (ARE) system and up-regulates downstream NAD(P)H:quinone oxidoreductase 1 (NQO1) and heme oxygenase-1 (HO-1). Anti-inflammatory and cytoprotective effects of Lico-E are attenuated in siRNA-mediated Nrf2-silencing cells as well as in the presence with specific inhibitor of HO-1 or NQO1, respectively. Lico-E also has neuroprotective effect against 1-methyl-4-phenyl-1,2,3,6-tetrahydropyridine-induced nigrostriatal dopaminergic neurodegeneration in mice, with up-regulation of HO-1 and NQO1 in the substantia nigra of the brain. This study demonstrates that Lico-E is a potential activator of the Nrf2/ARE-dependent pathway and is therapeutically relevant not only to oxidative-stress-related neurodegeneration but also inflammatory responses of microglial cells both in vitro and in vivo. Copyright © 2012 Elsevier Inc. All rights reserved.

  14. Berberine, an isoquinoline alkaloid suppresses TXNIP mediated NLRP3 inflammasome activation in MSU crystal stimulated RAW 264.7 macrophages through the upregulation of Nrf2 transcription factor and alleviates MSU crystal induced inflammation in rats.

    PubMed

    Dinesh, Palani; Rasool, MahaboobKhan

    2017-03-01

    The current study was designed to investigate the therapeutic potential of berberine on monosodium urate (MSU) crystal stimulated RAW 264.7 macrophages and in MSU crystal induced rats. Our results indicate that berberine (25, 50 and 75μM) suppressed the levels of pro-inflammatory cytokines (interleukin-1beta (IL-1β) and tumor necrosis factor alpha (TNFα)) and intracellular reactive oxygen species in MSU crystal stimulated RAW 264.7 macrophages. The mRNA expression levels of IL-1β, caspase 1, nucleotide-binding oligomerization domain-like receptor pyrin domain containing 3 (NLRP3), thioredoxin interacting protein (TXNIP) and kelch-like ECH-associated protein 1 (Keap1) were found downregulated with the upregulation of nuclear factor erythroid-2-related factor 2 (Nrf2) transcription factor and its associated anti-oxidant enzymes: Heme oxygenase I (HO-1), superoxide dismutase (SOD1), glutathione peroxidase (GPx), NADPH quinone oxidoreductase-1 (NQO1) and catalase (CAT) in MSU crystal stimulated RAW 264.7 macrophages upon berberine treatment. Subsequently, western blot analysis revealed that berberine decreased the protein expression of IL-1β and caspase 1 and increased Nrf2 expression in RAW 264.7 macrophages. Immunofluorescence analysis also explored increased expression of Nrf2 in MSU crystal stimulated RAW 264.7 macrophages by berberine treatment. In addition, the paw edema, pain score, pro-inflammatory cytokines (IL-1β and TNFα) and articular elastase activity were found significantly reduced in berberine (50mg/kgb·wt) administered MSU crystal-induced rats. Conclusively, our current findings suggest that berberine may represent as a potential candidate for the treatment of gouty arthritis by suppressing inflammatory mediators and activating Nrf2 anti-oxidant pathway. Copyright © 2016 Elsevier B.V. All rights reserved.

  15. Argon protects against hypoxic-ischemic brain injury in neonatal rats through activation of nuclear factor (erythroid-derived 2)-like 2

    PubMed Central

    Zhao, Hailin; Mitchell, Sian; Ciechanowicz, Sarah; Savage, Sinead; Wang, Tianlong; Ji, Xunming; Ma, Daqing

    2016-01-01

    Perinatal hypoxic ischaemic encephalopathy (HIE) has a high mortality rate with neuropsychological impairment. This study investigated the neuroprotective effects of argon against neonatal hypoxic-ischaemic brain injury. In vitro cortical neuronal cell cultures derived from rat foetuses were subjected to an oxygen and glucose deprivation (OGD) challenge for 90 minutes and then exposed to 70% argon or nitrogen with 5% carbon dioxide and balanced with oxygen for 2 hours. In vivo, seven-day-old rats were subjected to unilateral common carotid artery ligation followed by hypoxic (8% oxygen balanced with nitrogen) insult for 90 minutes. They were exposed to 70% argon or nitrogen balanced with oxygen for 2 hours. In vitro, argon treatment of cortical neuronal cultures resulted in a significant increase of p-mTOR and Nuclear factor (erythroid-derived 2)-like 2(Nrf2) and protection against OGD challenge. Inhibition of m-TOR through Rapamycin or Nrf2 through siRNA abolished argon-mediated cyto-protection. In vivo, argon exposure significantly enhanced Nrf2 and its down-stream effector NAD(P)H Dehydrogenase, Quinone 1(NQO1) and superoxide dismutase 1(SOD1). Oxidative stress, neuroinflammation and neuronal cell death were significantly decreased and brain infarction was markedly reduced. Blocking PI-3K through wortmannin or ERK1/2 through U0126 attenuated argon-mediated neuroprotection. These data provide a new molecular mechanism for the potential application of argon as a neuroprotectant in HIE. PMID:27016422

  16. Sulforaphane attenuation of experimental diabetic nephropathy involves GSK-3 beta/Fyn/Nrf2 signaling pathway.

    PubMed

    Shang, Guoguo; Tang, Xinjun; Gao, Pan; Guo, Fanli; Liu, Hongpeng; Zhao, Zhonghua; Chen, Qi; Jiang, Tao; Zhang, Nong; Li, Hui

    2015-06-01

    Sulforaphane (SFN), the bioactive component of cruciferous vegetables, is a potent indirect antioxidant. Oxidative stress and activation of glycogen synthase kinase 3beta (GSK3β) are two major contributors to the pathogenesis of diabetic nephropathy (DN). Here, we investigated whether and how SFN affected GSK3β in experimental models of DN in vivo and in vitro. SFN treatment obviously prevented the increase in urine albumin excretion, matrix expansion, transforming growth factor-β1 expression, fibronectin and type IV collagen deposition in the diabetic kidney. Simultaneously, the level of 8-oxo-deoxyguanosine, an indicator of oxidative damage, was markedly lowered in SFN-treated diabetic rats, together with a significant reduction in activity of the GSK-3β/Fyn axis and an evident activation of Nrf2 signaling. Similarly, antifibrotic effects of SFN, parallel to enhanced inhibitory Ser9-phosphorylation of GSK3β and Fyn/Nrf2 nuclear export/import, were observed in the cultured rat mesangial cells (RMC) exposed to high glucose. The salutary effects of SFN on high-glucose-stimulated RMC were abolished by overexpression of GSK3β while being rescued by lithium chloride, a well-known GSK3β inhibitor. Taken together, our findings suggested that SFN ameliorated experimental diabetic nephropathy, at least in part, via GSK3β/Fyn/Nrf2 signaling pathway. Copyright © 2015 Elsevier Inc. All rights reserved.

  17. Curcumin analog 1, 5-bis (2-trifluoromethylphenyl)-1, 4-pentadien-3-one exhibits enhanced ability on Nrf2 activation and protection against acrolein-induced ARPE-19 cell toxicity

    DOE Office of Scientific and Technical Information (OSTI.GOV)

    Li, Yuan; Zou, Xuan; Cao, Ke

    2013-11-01

    Curcumin, a phytochemical agent in the spice turmeric, has received increasing attention for its anticancer, anti-inflammatory and antioxidant properties. However, application of curcumin has been limited due to its insolubility in water and poor bioavailability both clinically and experimentally. In addition, the protective effects and mechanisms of curcumin in eye diseases have been poorly studied. In the present study, we synthesized a curcumin analog, 1, 5-bis (2-trifluoromethylphenyl)-1, 4-pentadien-3-one (C3), which displayed improved protective effect against acrolein-induced toxicity in a human retinal pigment epithelial cell line (ARPE-19). At 5 μM, curcumin completely protected against acrolein-induced cell oxidative damage and preserved GSHmore » levels and mitochondrial function. Surprisingly, C3 displayed a complete protective effect at 0.5 μM, which was much more efficient than curcumin. Both 0.5 μM C3 and 5 μM curcumin induced Nrf2 nuclear translocation and Nrf2 target genes transcription similarly. Experiments using Nrf2 siRNA showed that the protective effects of curcumin and C3 were eliminated by Nrf2 knockdown. Additionally, both curcumin and C3 activated the PI3/Akt pathway, however, Nrf2 activation was independent of this pathway, and therefore, we hypothesized that both curcumin and C3 activated phase II enzymes via directly disrupting the Nrf2/Keap1 complex and promoting Nrf2's nuclear translocation. Since acrolein challenge of ARPE-19 cells has been used as a model of smoking and age-related macular degeneration (AMD), we concluded that the curcumin analog, C3, may be a more promising drug candidate for its potential application for the prevention and treatment of eye diseases, such as AMD. - Highlights: • We examine toxicity effects of cigarette smoking component acrolein in retina cells. • We report a more efficient curcumin analog (C3) protecting cellular function. • Mitochondrial function and phase II enzyme activation are

  18. Transcription factor Nrf2 mediates an adaptive response to sulforaphane that protects fibroblasts in vitro against the cytotoxic effects of electrophiles, peroxides and redox-cycling agents

    DOE Office of Scientific and Technical Information (OSTI.GOV)

    Higgins, Larry G.; Kelleher, Michael O.; Eggleston, Ian M.

    2009-06-15

    Sulforaphane can stimulate cellular adaptation to redox stressors through transcription factor Nrf2. Using mouse embryonic fibroblasts (MEFs) as a model, we show herein that the normal homeostatic level of glutathione in Nrf2{sup -/-} MEFs was only 20% of that in their wild-type counterparts. Furthermore, the rate of glutathione synthesis following its acute depletion upon treatment with 3 {mu}mol/l sulforaphane was very substantially lower in Nrf2{sup -/-} MEFs than in wild-type cells, and the rebound leading to a {approx} 1.9-fold increase in glutathione that occurred 12-24 h after Nrf2{sup +/+} MEFs were treated with sulforaphane was not observed in Nrf2{sup -/-}more » fibroblasts. Wild-type MEFs that had been pre-treated for 24 h with 3 {mu}mol/l sulforaphane exhibited between 1.4- and 3.2-fold resistance against thiol-reactive electrophiles, including isothiocyanates, {alpha},{beta}-unsaturated carbonyl compounds (e.g. acrolein), aryl halides and alkene epoxides. Pre-treatment of Nrf2{sup +/+} MEFs with sulforaphane also protected against hydroperoxides (e.g. cumene hydroperoxide, CuOOH), free radical-generating compounds (e.g. menadione), and genotoxic electrophiles (e.g. chlorambucil). By contrast, Nrf2{sup -/-} MEFs were typically {approx} 50% less tolerant of these agents than wild-type fibroblasts, and sulforaphane pre-treatment did not protect the mutant cells against xenobiotics. To test whether Nrf2-mediated up-regulation of glutathione represents the major cytoprotective mechanism stimulated by sulforaphane, 5 {mu}mol/l buthionine sulfoximine (BSO) was used to inhibit glutathione synthesis. In Nrf2{sup +/+} MEFs pre-treated with sulforaphane, BSO diminished intrinsic resistance and abolished inducible resistance to acrolein, CuOOH and chlorambucil, but not menadione. Thus Nrf2-dependent up-regulation of GSH is the principal mechanism by which sulforaphane pre-treatment induced resistance to acrolein, CuOOH and chlorambucil, but not menadione.« less

  19. Lactucopicrin ameliorates oxidative stress mediated by scopolamine-induced neurotoxicity through activation of the NRF2 pathway.

    PubMed

    Venkatesan, Ramu; Subedi, Lalita; Yeo, Eui-Ju; Kim, Sun Yeou

    2016-10-01

    Cholinergic activity plays a vital role in cognitive function, and is reduced in individuals with neurodegenerative diseases. Scopolamine, a muscarinic cholinergic antagonist, has been employed in many studies to understand, identify, and characterize therapeutic targets for Alzheimer's disease (AD). Scopolamine-induced dementia is associated with impairments in memory and cognitive function, as seen in patients with AD. The current study aimed to investigate the molecular mechanisms underlying scopolamine-induced cholinergic neuronal dysfunction and the neuroprotective effect of lactucopicrin, an inhibitor of acetylcholine esterase (AChE). We investigated apoptotic cell death, caspase activation, generation of reactive oxygen species (ROS), mitochondrial dysfunction, and the expression levels of anti- and pro-apoptotic proteins in scopolamine-treated C6 cells. We also analyzed the expression levels of antioxidant enzymes and nuclear factor (erythroid-derived 2)-like 2 (NRF2) in C6 cells and neurite outgrowth in N2a neuroblastoma cells. Our results revealed that 1 h scopolamine pre-treatment induced cytotoxicity by increasing apoptotic cell death via oxidative stress-mediated caspase 3 activation and mitochondrial dysfunction. Scopolamine also downregulated the expression the antioxidant enzymes superoxide dismutase, glutathione peroxidase, and catalase, and the transcription factor NRF2. Lactucopicrin treatment protected C6 cells from scopolamine-induced toxicity by reversing the effects of scopolamine on those markers of toxicity. In addition, scopolamine attenuated the secretion of neurotrophic nerve growth factor (NGF) in C6 cells and neurite outgrowth in N2a cells. As expected, lactucopicrin treatment enhanced NGF secretion and neurite outgrowth. Our study is the first to show that lactucopicrin, a potential neuroprotective agent, ameliorates scopolamine-induced cholinergic dysfunction via NRF2 activation and subsequent expression of antioxidant enzymes

  20. Butein induction of HO-1 by p38 MAPK/Nrf2 pathway in adipocytes attenuates high-fat diet induced adipose hypertrophy in mice.

    PubMed

    Wang, Zheng; Ka, Sun-O; Lee, Youngyi; Park, Byung-Hyun; Bae, Eun Ju

    2017-03-15

    Adipose tissue inflammation and oxidative stress are key components in the development of obesity and insulin resistance. Heme oxygenase (HO)-1 in adipocytes protects against obesity and adipose dysfunction. In this study, we report the identification of butein, a flavonoid chalcone, as a novel inducer of HO-1 expression in adipocytes in vitro and in vivo. Butein upregulated HO-1 mRNA and protein expression in 3T3-L1 adipocytes, accompanied by Kelch-Like ECH-Associated Protein (Keap) 1 degradation and increase in the nuclear level of nuclear factor erythroid 2-related factor 2 (Nrf2). Butein modulation of Keap1 and Nrf2 as well as HO-1 upregulation was reversed by pretreatment with p38 MAPK inhibitor SB203580, indicating the involvement of p38 MAPK in butein activation of Nrf2 in adipocytes. In addition, HO-1 activation by butein led to the inhibitions of reactive oxygen species and adipocyte differentiation, as evidenced by the fact that butein repression of reactive oxygen species and adipogenesis was reversed by pretreatment with HO-1 inhibitor SnPP. Induction of HO-1 expression by butein was also demonstrated in the adipose tissue of C57BL/6 mice fed a high-fat diet administered along with butein for three weeks, and correlated with the inhibitions of adiposity and adipose tissue inflammation, which were reversed by co-administration of SnPP. Altogether, our results demonstrate that butein activates the p38 MAPK/Nrf2/HO-1 pathway to act as a potent inhibitor of adipose hypertrophy and inflammation in a diet-induced obesity model and thus has potential for suppressing obesity-linked metabolic syndrome. Copyright © 2017 Elsevier B.V. All rights reserved.