Sample records for nadph oxidase inhibition

  1. Inhibition of Human Vascular NADPH Oxidase by Apocynin Derived Oligophenols

    PubMed Central

    Mora-Pale, Mauricio; Weïwer, Michel; Yu, Jingjing; Linhardt, Robert J.; Dordick, Jonathan S.

    2009-01-01

    Enzymatic oxidation of apocynin, which may mimic in vivo metabolism, affords a large number of oligomers (apocynin oxidation products, AOP) that inhibit vascular NADPH oxidase. In vitro studies of NADPH oxidase activity were performed to identify active inhibitors, resulting in a trimer hydroxylated quinone (IIIHyQ) that inhibited NADPH oxidase with an IC50 = 31 nM. Apocynin itself possessed minimal inhibitory activity. NADPH oxidase is believed to be inhibited through prevention of the interaction between two NADPH oxidase subunits, p47phox and p22phox. To that end, while apocynin was unable to block the interaction of his-tagged p47phox with a surface immobilized biotinalyted p22phox peptide, the IIIHyQ product strongly interfered with this interaction (apparent IC50 = 1.6 μM). These results provide evidence that peroxidase-catalyzed AOP, which consist of oligomeric phenols and quinones, inhibit critical interactions that are involved in the assembly and activation of human vascular NADPH oxidase. PMID:19523836

  2. Inhibition of the NADPH oxidase regulates HO-1 expression in chronic myeloid leukemia

    PubMed Central

    Singh, Melissa M.; Irwin, Mary E.; Gao, Yin; Ban, Kechen; Shi, Ping; Arlinghaus, Ralph B.; Amin, Hesham M.; Chandra, Joya

    2011-01-01

    Background Patients with blast crisis phase chronic myelogeneous leukemia (CML) have poor response to tyrosine kinase inhibitors designed to inhibit the BCR-ABL1 oncogene. Recent work has shown that heme oxygenase 1 (HO-1) expression is increased in BCR-ABL1 expressing cells and that inhibition of HO-1 in CML leads to reduced cellular growth suggesting HO-1 may be a plausible target for therapy. Here we sought to clarify the mechanism of HO-1 overexpression and the role of the NADPH oxidase as a contributor to this mechanism in CML. Methods HO-1 expression was evaluated in CML bone marrow specimens from patients in various stages of disease, in a transplant based model for CML and in CML cell lines. Chemical and genetic inhibition of the NADPH oxidase was carried out in CML cells. Results Blast crisis CML patient specimens displayed higher levels of HO-1 staining than chronic or accelerated phase. HO-1 upregulation in BCR-ABL1 expressing cells was suppressed by diphenyliodonium (DPI), a chemical inhibitor of the NADPH oxidase. Targeting the NADPH oxidase through RNAi to Rac1, a dominant negative Rac1 construct or an inhibitor of Rac1 activity also blunted HO-1 protein expression. Moreover, inhibition of the NADPH oxidase by RNAi directed towards p47phox similarly abrogated HO-1 levels. Conclusion BCR-ABL1 expression upregulates HO-1, a survival factor for CML cells. This upregulation is more pronounced in blast crisis CML relative to early stage disease and is mediated by the NADPH oxidase components Rac1 and p47phox. Expression of p47phox is increased in BCR-ABL1 expressing cells. PMID:22139798

  3. Resveratrol protects vascular endothelial cells from high glucose-induced apoptosis through inhibition of NADPH oxidase activation-driven oxidative stress.

    PubMed

    Chen, Feng; Qian, Li-Hua; Deng, Bo; Liu, Zhi-Min; Zhao, Ying; Le, Ying-Ying

    2013-09-01

    Hyperglycemia-induced oxidative stress has been implicated in diabetic vascular complications in which NADPH oxidase is a major source of reactive oxygen species (ROS) generation. Resveratrol is a naturally occurring polyphenol, which has vasoprotective effects in diabetic animal models and inhibits high glucose (HG)-induced oxidative stress in endothelial cells. We aimed to examine whether HG-induced NADPH oxidase activation and ROS production contribute to glucotoxicity to endothelial cells and the effect of resveratrol on glucotoxicity. Using a murine brain microvascular endothelial cell line bEnd3, we found that NADPH oxidase inhibitor (apocynin) and resveratrol both inhibited HG-induced endothelial cell apoptosis. HG-induced elevation of NADPH oxidase activity and production of ROS were inhibited by apocynin, suggesting that HG induces endothelial cell apoptosis through NADPH oxidase-mediated ROS production. Mechanistic studies revealed that HG upregulated NADPH oxidase subunit Nox1 but not Nox2, Nox4, and p22(phox) expression through NF-κB activation, which resulted in elevation of NADPH oxidase activity and consequent ROS production. Resveratrol prevented HG-induced endothelial cell apoptosis through inhibiting HG-induced NF-κB activation, NADPH oxidase activity elevation, and ROS production. HG induces endothelial cell apoptosis through NF-κB/NADPH oxidase/ROS pathway, which was inhibited by resveratrol. Our findings provide new potential therapeutic targets against brain vascular complications of diabetes. © 2013 John Wiley & Sons Ltd.

  4. NADPH Oxidase Inhibition Improves Neurological Outcomes in Surgically-Induced Brain Injury

    PubMed Central

    Lo, Wendy; Bravo, Thomas; Jadhav, Vikram; Zhang, John H.; Tang, Jiping

    2007-01-01

    Neurosurgical procedures can result in brain injury by various means including direct trauma, hemorrhage, retractor stretch, and electrocautery. This surgically-induced brain injury (SBI) can cause post-operative complications such as brain edema. By creating a mouse model of SBI, we tested whether NADPH oxidase, an important reactive oxygen species producing enzyme, is involved in SBI using transgenic mice lacking gp91phox subunit of NADPH oxidase (gp91phox KO) and apocynin, a specific inhibitor of NADPH oxidase. Neurological function and brain edema were evaluated at 24 hours post-SBI in gp91phox KO and wild-type littermates grouped into SBI and sham-surgery groups. Alternatively, mice were grouped into vehicle- and apocynin-treated (5mg/kg, i.p. 30 minutes before SBI) groups. Oxidative stress indicated by lipid peroxidation (LPO) was measured at 3 and 24 hours post SBI. The gp91phox KO mice, but not the apocynin-treated mice showed significantly improved neurological scores. Brain edema was observed in both gp91phox KO and wild-type groups after SBI; however, there was no significant difference between these two groups. Brain edema was also not affected by apocynin-pretreatment. LPO levels were significantly higher in SBI group in both gp91phox KO and wild-type groups as compared to sham group. A trend, although without statistical significance, was noted towards attenuation of LPO in the gp91phox KO animals as compared to wild-type group. LPO levels were significantly attenuated at 3 hours post-SBI by apocynin pretreatment but not at 24 hours post-SBI. These results suggest that chronic and acute inhibition of NADPH oxidase activity does not reduce brain edema after SBI. Long-term inhibition of NADPH oxidase, however improves neurological functions after SBI. PMID:17317004

  5. Targeting NADPH oxidases in vascular pharmacology

    PubMed Central

    Schramm, Agata; Matusik, Paweł; Osmenda, Grzegorz; Guzik, Tomasz J

    2012-01-01

    Oxidative stress is a molecular dysregulation in reactive oxygen species (ROS) metabolism, which plays a key role in the pathogenesis of atherosclerosis, vascular inflammation and endothelial dysfunction. It is characterized by a loss of nitric oxide (NO) bioavailability. Large clinical trials such as HOPE and HPS have not shown a clinical benefit of antioxidant vitamin C or vitamin E treatment, putting into question the role of oxidative stress in cardiovascular disease. A change in the understanding of the molecular nature of oxidative stress has been driven by the results of these trials. Oxidative stress is no longer perceived as a simple imbalance between the production and scavenging of ROS, but as a dysfunction of enzymes involved in ROS production. NADPH oxidases are at the center of these events, underlying the dysfunction of other oxidases including eNOS uncoupling, xanthine oxidase and mitochondrial dysfunction. Thus NADPH oxidases are important therapeutic targets. Indeed, HMG-CoA reductase inhibitors (statins) as well as drugs interfering with the renin-angiotensin-aldosterone system inhibit NADPH oxidase activation and expression. Angiotensin-converting enzyme (ACE) inhibitors, AT1 receptor antagonists (sartans) and aliskiren, as well as spironolactone or eplerenone, have been discussed. Molecular aspects of NADPH oxidase regulation must be considered, while thinking about novel pharmacological targeting of this family of enzymes consisting of several homologs Nox1, Nox2, Nox3, Nox4 and Nox5 in humans. In order to properly design trials of antioxidant therapies, we must develop reliable techniques for the assessment of local and systemic oxidative stress. Classical antioxidants could be combined with novel oxidase inhibitors. In this review, we discuss NADPH oxidase inhibitors such as VAS2870, VAS3947, GK-136901, S17834 or plumbagin. Therefore, our efforts must focus on generating small molecular weight inhibitors of NADPH oxidases, allowing the

  6. Current status of NADPH oxidase research in cardiovascular pharmacology.

    PubMed

    Rodiño-Janeiro, Bruno K; Paradela-Dobarro, Beatriz; Castiñeiras-Landeira, María Isabel; Raposeiras-Roubín, Sergio; González-Juanatey, José R; Alvarez, Ezequiel

    2013-01-01

    The implications of reactive oxygen species in cardiovascular disease have been known for some decades. Rationally, therapeutic antioxidant strategies combating oxidative stress have been developed, but the results of clinical trials have not been as good as expected. Therefore, to move forward in the design of new therapeutic strategies for cardiovascular disease based on prevention of production of reactive oxygen species, steps must be taken on two fronts, ie, comprehension of reduction-oxidation signaling pathways and the pathophysiologic roles of reactive oxygen species, and development of new, less toxic, and more selective nicotinamide adenine dinucleotide phosphate (NADPH) oxidase inhibitors, to clarify both the role of each NADPH oxidase isoform and their utility in clinical practice. In this review, we analyze the value of NADPH oxidase as a therapeutic target for cardiovascular disease and the old and new pharmacologic agents or strategies to prevent NADPH oxidase activity. Some inhibitors and different direct or indirect approaches are available. Regarding direct NADPH oxidase inhibition, the specificity of NADPH oxidase is the focus of current investigations, whereas the chemical structure-activity relationship studies of known inhibitors have provided pharmacophore models with which to search for new molecules. From a general point of view, small-molecule inhibitors are preferred because of their hydrosolubility and oral bioavailability. However, other possibilities are not closed, with peptide inhibitors or monoclonal antibodies against NADPH oxidase isoforms continuing to be under investigation as well as the ongoing search for naturally occurring compounds. Likewise, some different approaches include inhibition of assembly of the NADPH oxidase complex, subcellular translocation, post-transductional modifications, calcium entry/release, electron transfer, and genetic expression. High-throughput screens for any of these activities could provide new

  7. Current status of NADPH oxidase research in cardiovascular pharmacology

    PubMed Central

    Rodiño-Janeiro, Bruno K; Paradela-Dobarro, Beatriz; Castiñeiras-Landeira, María Isabel; Raposeiras-Roubín, Sergio; González-Juanatey, José R; Álvarez, Ezequiel

    2013-01-01

    The implications of reactive oxygen species in cardiovascular disease have been known for some decades. Rationally, therapeutic antioxidant strategies combating oxidative stress have been developed, but the results of clinical trials have not been as good as expected. Therefore, to move forward in the design of new therapeutic strategies for cardiovascular disease based on prevention of production of reactive oxygen species, steps must be taken on two fronts, ie, comprehension of reduction-oxidation signaling pathways and the pathophysiologic roles of reactive oxygen species, and development of new, less toxic, and more selective nicotinamide adenine dinucleotide phosphate (NADPH) oxidase inhibitors, to clarify both the role of each NADPH oxidase isoform and their utility in clinical practice. In this review, we analyze the value of NADPH oxidase as a therapeutic target for cardiovascular disease and the old and new pharmacologic agents or strategies to prevent NADPH oxidase activity. Some inhibitors and different direct or indirect approaches are available. Regarding direct NADPH oxidase inhibition, the specificity of NADPH oxidase is the focus of current investigations, whereas the chemical structure-activity relationship studies of known inhibitors have provided pharmacophore models with which to search for new molecules. From a general point of view, small-molecule inhibitors are preferred because of their hydrosolubility and oral bioavailability. However, other possibilities are not closed, with peptide inhibitors or monoclonal antibodies against NADPH oxidase isoforms continuing to be under investigation as well as the ongoing search for naturally occurring compounds. Likewise, some different approaches include inhibition of assembly of the NADPH oxidase complex, subcellular translocation, post-transductional modifications, calcium entry/release, electron transfer, and genetic expression. High-throughput screens for any of these activities could provide new

  8. SIRT1 inhibits NADPH oxidase activation and protects endothelial function in the rat aorta: implications for vascular aging.

    PubMed

    Zarzuelo, María José; López-Sepúlveda, Rocío; Sánchez, Manuel; Romero, Miguel; Gómez-Guzmán, Manuel; Ungvary, Zoltan; Pérez-Vizcaíno, Francisco; Jiménez, Rosario; Duarte, Juan

    2013-05-01

    Vascular aging is characterized by up-regulation of NADPH oxidase, oxidative stress and endothelial dysfunction. Previous studies demonstrate that the activity of the evolutionarily conserved NAD(+)-dependent deacetylase SIRT1 declines with age and that pharmacological activators of SIRT1 confer significant anti-aging cardiovascular effects. To determine whether dysregulation of SIRT1 promotes NADPH oxidase-dependent production of reactive oxygen species (ROS) and impairs endothelial function we assessed the effects of three structurally different inhibitors of SIRT1 (nicotinamide, sirtinol, EX527) in aorta segments isolated from young Wistar rats. Inhibition of SIRT1 induced endothelial dysfunction, as shown by the significantly reduced relaxation to the endothelium-dependent vasodilators acetylcholine and the calcium ionophore A23187. Endothelial dysfunction induced by SIRT1 inhibition was prevented by treatment of the vessels with the NADPH oxidase inhibitor apocynin or superoxide dismutase. Inhibition of SIRT1 significantly increased vascular superoxide production, enhanced NADPH oxidase activity, and mRNA expression of its subunits p22(phox) and NOX4, which were prevented by resveratrol. Peroxisome proliferator-activated receptor-α (PPARα) activation mimicked the effects of resveratrol while PPARα inhibition prevented the effects of this SIRT1 activator. SIRT1 co-precipitated with PPARα and nicotinamide increased the acetylation of the PPARα coactivator PGC-1α, which was suppressed by resveratrol. In conclusion, impaired activity of SIRT1 induces endothelial dysfunction and up-regulates NADPH oxidase-derived ROS production in the vascular wall, mimicking the vascular aging phenotype. Moreover, a new mechanism for controlling endothelial function after SIRT1 activation involves a decreased PGC-1α acetylation and the subsequent PPARα activation, resulting in both decreased NADPH oxidase-driven ROS production and NO inactivation. Copyright © 2013

  9. The voltage dependence of NADPH oxidase reveals why phagocytes need proton channels

    NASA Astrophysics Data System (ADS)

    DeCoursey, Thomas E.; Morgan, Deri; Cherny, Vladimir V.

    2003-04-01

    The enzyme NADPH oxidase in phagocytes is important in the body's defence against microbes: it produces superoxide anions (O2-, precursors to bactericidal reactive oxygen species). Electrons move from intracellular NADPH, across a chain comprising FAD (flavin adenine dinucleotide) and two haems, to reduce extracellular O2 to O2-. NADPH oxidase is electrogenic, generating electron current (Ie) that is measurable under voltage-clamp conditions. Here we report the complete current-voltage relationship of NADPH oxidase, the first such measurement of a plasma membrane electron transporter. We find that Ie is voltage-independent from -100mV to >0mV, but is steeply inhibited by further depolarization, and is abolished at about +190mV. It was proposed that H+ efflux mediated by voltage-gated proton channels compensates Ie, because Zn2+ and Cd2+ inhibit both H+ currents and O2- production. Here we show that COS-7 cells transfected with four NADPH oxidase components, but lacking H+ channels, produce O2- in the presence of Zn2+ concentrations that inhibit O2- production in neutrophils and eosinophils. Zn2+ does not inhibit NADPH oxidase directly, but through effects on H+ channels. H+ channels optimize NADPH oxidase function by preventing membrane depolarization to inhibitory voltages.

  10. NADPH Oxidase Signaling Pathway Mediates Mesenchymal Stem Cell-Induced Inhibition of Hepatic Stellate Cell Activation.

    PubMed

    Qiao, Haowen; Zhou, Yu; Qin, Xingping; Cheng, Jing; He, Yun; Jiang, Yugang

    2018-01-01

    Bone marrow-derived mesenchymal stem cells (BMSCs) have blossomed into an effective approach with great potential for the treatment of liver fibrosis. The aim of this study was to investigate the underlying antifibrosis mechanisms by which the BMSC inhibit activated hepatic stellate cells (HSCs) in vivo and in vitro. To study the effect of human bone marrow-derived mesenchymal stem cells (hBM-MSCs) on activated HSCs, we used HSCs and the coculture systems to evaluate the inhibition of activated HSCs from the aspects of the apoptosis of activated HSCs. In addition, activation of NADPH oxidase pathway and the changes in liver histopathology were tested by using the carbon tetrachloride- (CCl 4 -) induced liver fibrosis in mice. Introduction of hBM-MSCs significantly inhibited the proliferation of activated HSCs by inducing the apoptosis process of activated HSCs. The effect of hBM-MSCs reduced the signaling pathway of NADPH oxidase in activated HSCs. Besides, the signaling pathway of NADPH oxidase mediated hBM-MSC upregulation of the expression of the peroxisome proliferator-activated receptor γ and downregulation of the expression of α 1(I) collagen and alpha-smooth muscle actin ( α -SMA) in activated HSCs. Moreover, the hBM-MSC-induced decrease in the signaling pathway of NADPH oxidase was accompanied by the decrease of the activated HSC number and liver fibrosis in a mouse model of CCl 4 -induced liver fibrosis. The hBM-MSCs act as a promising drug source against liver fibrosis development with respect to hepatopathy as a therapeutic target.

  11. Pharmacological inhibition of NADPH oxidase protects against cisplatin induced nephrotoxicity in mice by two step mechanism.

    PubMed

    Wang, Yimin; Luo, Xiao; Pan, Hao; Huang, Wei; Wang, Xueping; Wen, Huali; Shen, Kezhen; Jin, Baiye

    2015-09-01

    Cisplatin induced nephrotoxicity is primarily caused by ROS (Reactive Oxygen Species) induced proximal tubular cell death. NADPH oxidase is major source of ROS production by cisplatin. Here, we reported that pharmacological inhibition of NADPH oxidase by acetovanillone (obtained from medicinal herb Picrorhiza kurroa) led to reduced cisplatin nephrotoxicity in mice. In this study we used various molecular biology and biochemistry methods a clinically relevant model of nephropathy, induced by an important chemotherapeutic drug cisplatin. Cisplatin-induced nephrotoxicity was evident by histological damage from loss of the tubular structure. The damage was also marked by the increase in blood urea nitrogen, creatinine, protein nitration as well as cell death markers such as caspase 3/7 activity and DNA fragmentation. Tubular cell death by cisplatin led to pro-inflammatory response by production of TNFα and IL1β followed by leukocyte/neutrophil infiltration which resulted in new wave of ROS involving more NADPH oxidases. Cisplatin-induced markers of kidney damage such as oxidative stress, cell death, inflammatory cytokine production and nephrotoxicity were attenuated by acetovanillone. In addition to that, acetovanillone enhanced cancer cell killing efficacy of cisplatin. Thus, pharmacological inhibition of NADPH oxidase can be protective for cisplatin-induced nephrotoxicity in mice. Copyright © 2015. Published by Elsevier Ltd.

  12. NADPH oxidase inhibition reduces tubular sodium transport and improves kidney oxygenation in diabetes.

    PubMed

    Persson, Patrik; Hansell, Peter; Palm, Fredrik

    2012-06-15

    Sustained hyperglycemia is associated with increased oxidative stress resulting in decreased intrarenal oxygen tension (Po(2)) due to increased oxygen consumption (Qo(2)). Chronic blockade of the main superoxide radicals producing system, the nicotinamide adenine dinucleotide phosphate (NADPH) oxidase, normalizes Qo(2) by isolated proximal tubular cells (PTC) and reduces proteinuria in diabetes. The aim was to investigate the effects of acute NADPH oxidase inhibition on tubular Na(+) transport and kidney Po(2) in vivo. Glomerular filtration rate (GFR), renal blood flow (RBF), filtration fraction (FF), Na(+) excretion, fractional Li(+) excretion, and intrarenal Po(2) was measured in control and streptozotocin-diabetic rats during baseline and after acute NADPH oxidase inhibition using apocynin. The effects on tubular transporters were investigated using freshly isolated PTC. GFR was increased in diabetics compared with controls (2.2 ± 0.3 vs. 1.4 ± 0.1 ml·min(-1)·kidney(-1)). RBF was similar in both groups, resulting in increased FF in diabetics. Po(2) was reduced in cortex and medulla in diabetic kidneys compared with controls (34.4 ± 0.7 vs. 42.5 ± 1.2 mmHg and 15.7 ± 1.2 vs. 25.5 ± 2.3 mmHg, respectively). Na(+) excretion was increased in diabetics compared with controls (24.0 ± 4.7 vs. 9.0 ± 2.0 μm·min(-1)·kidney(-1)). In controls, all parameters were unaffected. However, apocynin increased Na(+) excretion (+112%) and decreased fractional lithium reabsorption (-10%) in diabetics, resulting in improved cortical (+14%) and medullary (+28%) Po(2). Qo(2) was higher in PTC isolated from diabetic rats compared with control. Apocynin, dimethylamiloride, and ouabain reduced Qo(2), but the effects of combining apocynin with either dimethylamiloride or ouabain were not additive. In conclusion, NADPH oxidase inhibition reduces tubular Na(+) transport and improves intrarenal Po(2) in diabetes.

  13. NADPH oxidase mediates depressive behavior induced by chronic stress in mice.

    PubMed

    Seo, Ji-Seon; Park, Jin-Young; Choi, Juli; Kim, Tae-Kyung; Shin, Joo-Hyun; Lee, Ja-Kyeong; Han, Pyung-Lim

    2012-07-11

    Stress is a potent risk factor for depression, yet the underlying mechanism is not clearly understood. In the present study, we explored the mechanism of development and maintenance of depression in a stress-induced animal model. Mice restrained for 2 h daily for 14 d showed distinct depressive behavior, and the altered behavior persisted for >3 months in the absence of intervention. Acute restraint induced a surge of oxidative stress in the brain, and stress-induced oxidative stress progressively increased with repetition of stress. In vitro, the stress hormone glucocorticoid generated superoxide via upregulation of NADPH oxidase. Consistently, repeated restraints increased the expression of the key subunits of NADPH oxidase, p47phox and p67phox, in the brain. Moreover, stressed brains markedly upregulated the expression of p47phox to weak restress evoked in the poststress period, and this molecular response was reminiscent of amplified ROS surge to restress. Pharmacological inhibition of NADPH oxidase by the NADPH oxidase inhibitor apocynin during the stress or poststress period completely blocked depressive behavior. Consistently, heterozygous p47phox knock-out mice (p47phox(+/-)) or molecular inhibition of p47phox with Lenti shRNA-p47phox in the hippocampus suppressed depressive behavior. These results suggest that repeated stress promotes depressive behavior through the upregulation of NADPH oxidase and the resultant metabolic oxidative stress, and that the inhibition of NADPH oxidase provides beneficial antidepression effects.

  14. NADPH oxidase inhibitors: a patent review.

    PubMed

    Kim, Jung-Ae; Neupane, Ganesh Prasad; Lee, Eung Seok; Jeong, Byeong-Seon; Park, Byung Chul; Thapa, Pritam

    2011-08-01

    NADPH oxidases, a family of multi-subunit enzyme complexes, catalyze the production of reactive oxygen species (ROS), which may contribute to the pathogenesis of a variety of diseases. In addition to the first NADPH oxidase found in phagocytes, four non-phagocytic NADPH oxidase isoforms have been identified, which all differ in their catalytic subunit (Nox1-5) and tissue distribution. This paper provides a comprehensive review of the patent literature on NADPH oxidase inhibitors, small molecule Nox inhibitors, peptides and siRNAs. Since each member of the NADPH oxidase family has great potential as a therapeutic target, several different compounds have been registered as NADPH oxidase inhibitors in the patent literature. As yet, none have gone through clinical trials, and some have not completed preclinical trials, including safety and specificity evaluation. Recently, small molecule pyrazolopyridine and triazolopyrimidine derivatives have been submitted as potent NADPH oxidase inhibitors and reported as first-in-class inhibitors for idiopathic pulmonary fibrosis and acute stroke, respectively. Further clinical efficacy and safety data are warranted to prove their actual clinical utility.

  15. Preferential inhibition of the plasma membrane NADH oxidase (NOX) activity by diphenyleneiodonium chloride with NADPH as donor

    NASA Technical Reports Server (NTRS)

    Morre, D. James

    2002-01-01

    The cell-surface NADH oxidase (NOX) protein of plant and animal cells will utilize both NADH and NADPH as reduced electron donors for activity. The two activities are distinguished by a differential inhibition by the redox inhibitor diphenyleneiodonium chloride (DPI). Using both plasma membranes and cells, activity with NADPH as donor was markedly inhibited by DPI at submicromolar concentrations, whereas with NADH as donor, DPI was much less effective or had no effect on the activity. The possibility of the inhibition being the result of two different enzymes was eliminated by the use of a recombinant NOX protein. The findings support the concept that NOX proteins serve as terminal oxidases for plasma membrane electron transport involving cytosolic reduced pyridine nucleotides as the natural electron donors and with molecular oxygen as the electron acceptor.

  16. Deficiency of Rac1 Blocks NADPH Oxidase Activation, Inhibits Endoplasmic Reticulum Stress, and Reduces Myocardial Remodeling in a Mouse Model of Type 1 Diabetes

    PubMed Central

    Li, Jianmin; Zhu, Huaqing; Shen, E; Wan, Li; Arnold, J. Malcolm O.; Peng, Tianqing

    2010-01-01

    OBJECTIVE Our recent study demonstrated that Rac1 and NADPH oxidase activation contributes to cardiomyocyte apoptosis in short-term diabetes. This study was undertaken to investigate if disruption of Rac1 and inhibition of NADPH oxidase would prevent myocardial remodeling in chronic diabetes. RESEARCH DESIGN AND METHODS Diabetes was induced by injection of streptozotocin in mice with cardiomyocyte-specific Rac1 knockout and their wild-type littermates. In a separate experiment, wild-type diabetic mice were treated with vehicle or apocynin in drinking water. Myocardial hypertrophy, fibrosis, endoplasmic reticulum (ER) stress, inflammatory response, and myocardial function were investigated after 2 months of diabetes. Isolated adult rat cardiomyocytes were cultured and stimulated with high glucose. RESULTS In diabetic hearts, NADPH oxidase activation, its subunits' expression, and reactive oxygen species production were inhibited by Rac1 knockout or apocynin treatment. Myocardial collagen deposition and cardiomyocyte cross-sectional areas were significantly increased in diabetic mice, which were accompanied by elevated expression of pro-fibrotic genes and hypertrophic genes. Deficiency of Rac1 or apocynin administration reduced myocardial fibrosis and hypertrophy, resulting in improved myocardial function. These effects were associated with a normalization of ER stress markers' expression and inflammatory response in diabetic hearts. In cultured cardiomyocytes, high glucose–induced ER stress was inhibited by blocking Rac1 or NADPH oxidase. CONCLUSIONS Rac1 via NADPH oxidase activation induces myocardial remodeling and dysfunction in diabetic mice. The role of Rac1 signaling may be associated with ER stress and inflammation. Thus, targeting inhibition of Rac1 and NADPH oxidase may be a therapeutic approach for diabetic cardiomyopathy. PMID:20522592

  17. Inhibition of arsenic induced-rat liver injury by grape seed exact through suppression of NADPH oxidase and TGF-{beta}/Smad activation

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

    Pan Xinjuan; Dai Yujie; Li Xing

    2011-08-01

    Chronic arsenic exposure induces oxidative damage to liver leading to liver fibrosis. We aimed to define the effect of grape seed extract (GSE), an antioxidant dietary supplement, on arsenic-induced liver injury. First, Male Sprague-Dawley rats were exposed to a low level of arsenic in drinking water (30 ppm) with or without GSE (100 mg/kg, every other day by oral gavage) for 12 months and the effect of GSE on arsenic-induced hepatotoxicity was examined. The results from this study revealed that GSE co-treatment significantly attenuated arsenic-induced low antioxidant defense, oxidative damage, proinflammatory cytokines and fibrogenic genes. Moreover, GSE reduced arsenic-stimulated Smad2/3more » phosphorylation and protein levels of NADPH oxidase subunits (Nox2, Nox4 and p47phox). Next, we explored the molecular mechanisms underlying GSE inhibition of arsenic toxicity using cultured rat hepatic stellate cells (HSCs). From the in vitro study, we found that GSE dose-dependently reduced arsenic-stimulated ROS production and NADPH oxidase activities. Both NADPH oxidases flavoprotein inhibitor DPI and Nox4 siRNA blocked arsenic-induced ROS production, whereas Nox4 overexpression suppressed the inhibitory effects of GSE on arsenic-induced ROS production and NADPH oxidase activities, as well as expression of TGF-{beta}1, type I procollagen (Coll-I) and {alpha}-smooth muscle actin ({alpha}-SMA) mRNA. We also observed that GSE dose-dependently inhibited TGF-{beta}1-induced transactivation of the TGF-{beta}-induced smad response element p3TP-Lux, and that forced expression of Smad3 attenuated the inhibitory effects of GSE on TGF-{beta}1-induced mRNA expression of Coll-I and {alpha}-SMA. Collectively, GSE could be a potential dietary therapeutic agent for arsenic-induced liver injury through suppression of NADPH oxidase and TGF-{beta}/Smad activation. - Research Highlights: > GSE attenuated arsenic-induced low antioxidant defense, oxidative damage, proinflammatory cytokines

  18. Naringin ameliorates diabetic nephropathy by inhibiting NADPH oxidase 4.

    PubMed

    Zhang, Junwei; Yang, Suxia; Li, Huicong; Chen, Fang; Shi, Jun

    2017-06-05

    Naringin, a naturally flavanone glycoside, has been previously demonstrated to alleviate diabetic kidney disease by inhibiting oxidative stress and inflammatory reaction. However, the underlying mechanism of naringin in diabetic nephropathy (DN) has not been fully elucidated. Here, the beneficial effect of naringin on DN in streptozotocin (STZ)-induced DN rats and high glucose (HG)-induced podocytes and its underlying mechanism were elaborated. The result revealed that naringin alleviated STZ-induced renal dysfunction and injury in DN rats, relieved STZ-induced oxidative stress in vivo and inhibited HG-induced apoptosis and reactive oxygen species level i20n vitro. More importantly, naringin inhibited NOX4 expression at mRNA and protein levels in STZ-induced DN rats and HG-induced podocytes. Loss of function indicated that NADPH oxidases 4 (NOX4) down-regulation suppressed apoptosis and reactive oxygen species level in HG-treated podocytes. Take together, this study demonstrated that naringin ameliorates diabetic nephropathy by inhibiting NOX4, contributing to a better understanding of the progression of DN. Copyright © 2017 Elsevier B.V. All rights reserved.

  19. Rosuvastatin prevents angiotensin II-induced vascular changes by inhibition of NAD(P)H oxidase and COX-1

    PubMed Central

    Colucci, Rocchina; Fornai, Matteo; Duranti, Emiliano; Antonioli, Luca; Rugani, Ilaria; Aydinoglu, Fatma; Ippolito, Chiara; Segnani, Cristina; Bernardini, Nunzia; Taddei, Stefano; Blandizzi, Corrado; Virdis, Agostino

    2013-01-01

    Background and Purpose NAD(P)H oxidase and COX-1 participate in vascular damage induced by angiotensin II. We investigated the effect of rosuvastatin on endothelial dysfunction, vascular remodelling, changes in extracellular matrix components and mechanical properties of small mesenteric arteries from angiotensin II-infused rats. Experimental Approach Male rats received angiotensin II (120 ng·kg−1·min−1, subcutaneously) for 14 days with or without rosuvastatin (10 mg·kg−1·day−1, oral gavage) or vehicle. Vascular functions and morphological parameters were assessed by pressurized myography. Key Results In angiotensin II-infused rats, ACh-induced relaxation was attenuated compared with controls, less sensitive to L-NAME, enhanced by SC-560 (COX-1 inhibitor) or SQ-29548 (prostanoid TP receptor antagonist), and normalized by the antioxidant ascorbic acid or NAD(P)H oxidase inhibitors. After rosuvastatin, relaxations to ACh were normalized, fully sensitive to L-NAME, and no longer affected by SC-560, SQ-29548 or NAD(P)H oxidase inhibitors. Angiotensin II enhanced intravascular superoxide generation, eutrophic remodelling, collagen and fibronectin depositions, and decreased elastin content, resulting in increased vessel stiffness. All these changes were prevented by rosuvastatin. Angiotensin II increased phosphorylation of NAD(P)H oxidase subunit p47phox and its binding to subunit p67phox, effects inhibited by rosuvastatin. Rosuvastatin down-regulated vascular Nox4/NAD(P)H isoform and COX-1 expression, attenuated the vascular release of 6-keto-PGF1α, and enhanced copper/zinc-superoxide dismutase expression. Conclusion and Implications Rosuvastatin prevents angiotensin II-induced alterations in resistance arteries in terms of function, structure, mechanics and composition. These effects depend on restoration of NO availability, prevention of NAD(P)H oxidase-derived oxidant excess, reversal of COX-1 induction and its prostanoid production, and stimulation of

  20. A novel domain of amino-Nogo-A protects HT22 cells exposed to oxygen glucose deprivation by inhibiting NADPH oxidase activity.

    PubMed

    Guo, Fan; Wang, Huiwen; Li, Liya; Zhou, Heng; Wei, Haidong; Jin, Weilin; Wang, Qiang; Xiong, Lize

    2013-04-01

    This study aimed to investigate the protective effect of the M9 region (residues 290-562) of amino-Nogo-A fused to the human immunodeficiency virus trans-activator TAT in an in vitro model of ischemia-reperfusion induced by oxygen-glucose deprivation (OGD) in HT22 hippocampal neurons, and to investigate the role of NADPH oxidase in this protection. Transduction of TAT-M9 was analyzed by immunofluorescence staining and western blot. The biologic activity of TAT-M9 was assessed by its effects against OGD-induced HT22 cell damage, compared with a mutant M9 fusion protein or vehicle. Cellular viability and lactate dehydrogenase (LDH) release were assessed. Neuronal apoptosis was evaluated by flow cytometry. The Bax/Bcl-2 ratio was determined by western blotting. Reactive oxygen species (ROS) levels and NADPH oxidase activity were also measured in the presence or absence of an inhibitor or activator of NADPH oxidase. Our results confirmed the delivery of the protein into HT22 cells by immunofluorescence and western blot. Addition of 0.4 μmol/L TAT-M9 to the culture medium effectively improved neuronal cell viability and reduced LDH release induced by OGD. The fusion protein also protected HT22 cells from apoptosis, suppressed overexpression of Bax, and inhibited the reduction in Bcl-2 expression. Furthermore, TAT-M9, as well as apocynin, decreased NADPH oxidase activity and ROS content. The protective effects of the TAT-M9 were reversed by TBCA, an agonist of NADPH oxidase. In conclusion, TAT-M9 could be successfully transduced into HT22 cells, and protected HT22 cells against OGD damage by inhibiting NADPH oxidase-mediated oxidative stress. These findings suggest that the TAT-M9 protein may be an efficient therapeutic agent for neuroprotection.

  1. Resveratrol prevents high glucose-induced epithelial-mesenchymal transition in renal tubular epithelial cells by inhibiting NADPH oxidase/ROS/ERK pathway.

    PubMed

    He, Ting; Guan, Xu; Wang, Song; Xiao, Tangli; Yang, Ke; Xu, Xinli; Wang, Junping; Zhao, Jinghong

    2015-02-15

    Resveratrol (RSV) is reported to have renoprotective activity against diabetic nephropathy, while the mechanisms underlying its function have not been fully elucidated. In this study, we investigate the effect and related mechanism of RSV against high glucose-induced epithelial to mesenchymal transition (EMT) in human tubular epithelial cells (HK-2). A typical EMT is induced by high glucose in HK-2 cells, accompanied by increased levels of reactive oxygen species (ROS). RSV exhibits a strong ability to inhibit high glucose-induced EMT by decreasing intracellular ROS levels via down-regulation of NADPH oxidase subunits NOX1 and NOX4. The activation of extracellular signal-regulated kinase (ERK1/2) is found to be involved in high glucose-induced EMT in HK-2 cells. RSV, like NADPH oxidase inhibitor diphenyleneiodonium, can block ERK1/2 activation induced by high glucose. Our results demonstrate that RSV is a potent agent against high glucose-induced EMT in renal tubular cells via inhibition of NADPH oxidase/ROS/ERK1/2 pathway. Copyright © 2014 Elsevier Ireland Ltd. All rights reserved.

  2. NADPH Oxidases in Vascular Pathology

    PubMed Central

    Konior, Anna; Schramm, Agata; Czesnikiewicz-Guzik, Marta

    2014-01-01

    Abstract Significance: Reactive oxygen species (ROS) play a critical role in vascular disease. While there are many possible sources of ROS, nicotinamide adenine dinucleotide phosphate (NADPH) oxidases play a central role. They are a source of “kindling radicals,” which affect other enzymes, such as nitric oxide synthase endothelial nitric oxide synthase or xanthine oxidase. This is important, as risk factors for atherosclerosis (hypertension, diabetes, hypercholesterolemia, and smoking) regulate the expression and activity of NADPH oxidases in the vessel wall. Recent Advances: There are seven isoforms in mammals: Nox1, Nox2, Nox3, Nox4, Nox5, Duox1 and Duox2. Nox1, Nox2, Nox4, and Nox5 are expressed in endothelium, vascular smooth muscle cells, fibroblasts, or perivascular adipocytes. Other homologues have not been found or are expressed at very low levels; their roles have not been established. Nox1/Nox2 promote the development of endothelial dysfunction, hypertension, and inflammation. Nox4 may have a role in protecting the vasculature during stress; however, when its activity is increased, it may be detrimental. Calcium-dependent Nox5 has been implicated in oxidative damage in human atherosclerosis. Critical Issues: NADPH oxidase-derived ROS play a role in vascular pathology as well as in the maintenance of normal physiological vascular function. We also discuss recently elucidated mechanisms such as the role of NADPH oxidases in vascular protection, vascular inflammation, pulmonary hypertension, tumor angiogenesis, and central nervous system regulation of vascular function and hypertension. Future Directions: Understanding the role of individual oxidases and interactions between homologues in vascular disease is critical for efficient pharmacological regulation of vascular NADPH oxidases in both the laboratory and clinical practice. Antioxid. Redox Signal. 20, 2794–2814. PMID:24180474

  3. PKC delta and NADPH oxidase in retinoic acid-induced neuroblastoma cell differentiation.

    PubMed

    Nitti, Mariapaola; Furfaro, Anna Lisa; Cevasco, Claudia; Traverso, Nicola; Marinari, Umberto Maria; Pronzato, Maria Adelaide; Domenicotti, Cinzia

    2010-05-01

    The role of reactive oxygen species (ROS) in the regulation of signal transduction processes has been well established in many cell types and recently the fine tuning of redox signalling in neurons received increasing attention. With regard to this, the involvement of NADPH oxidase (NOX) in neuronal pathophysiology has been proposed but deserves more investigation. In the present study, we used SH-SY5Y neuroblastoma cells to analyse the role of NADPH oxidase in retinoic acid (RA)-induced differentiation, pointing out the involvement of protein kinase C (PKC) delta in the activation of NOX. Retinoic acid induces neuronal differentiation as revealed by the increased expression of MAP2, the decreased cell doubling rate, and the gain in neuronal morphological features and these events are accompanied by the increased expression level of PKC delta and p67(phox), one of the components of NADPH oxidase. Using DPI to inhibit NOX activity we show that retinoic acid acts through this enzyme to induce morphological changes linked to the differentiation. Moreover, using rottlerin to inhibit PKC delta or transfection experiments to overexpress it, we show that retinoic acid acts through this enzyme to induce MAP2 expression and to increase p67(phox) membrane translocation leading to NADPH oxidase activation. These findings identify the activation of PKC delta and NADPH oxidase as crucial steps in RA-induced neuroblastoma cell differentiation. 2010 Elsevier Inc. All rights reserved.

  4. Sildenafil Promotes eNOS Activation and Inhibits NADPH Oxidase in the Transgenic Sickle Cell Mouse Penis

    PubMed Central

    Musicki, Biljana; Bivalacqua, Trinity J.; Champion, Hunter C.; Burnett, Arthur L.

    2014-01-01

    Introduction Sickle cell disease (SCD)-associated vasculopathy in the penis is characterized by aberrant nitric oxide and phosphodiesterase (PDE) 5 signaling, and by increased oxidative stress. Preliminary clinical trials show that continuous treatment with PDE5 inhibitor sildenafil unassociated with sexual activity decreases priapic activity in patients with SCD. However, the mechanism of its vasculoprotective effect in the penis remains unclear. Aims We evaluated whether continuous administration of PDE5 inhibitor sildenafil promotes eNOS function at posttranslational levels and decreases superoxide-producing enzyme NADPH oxidase activity in the sickle cell mouse penis. Methods SCD transgenic mice were used as an animal model of SCD. WT mice served as controls. Mice received treatment with the PDE5 inhibitor sildenafil (100 mg/kg/day) or vehicle for 3 weeks. eNOS phosphorylation on Ser-1177 (positive regulatory site), eNOS interactions with heat-shock protein 90 (HSP90) (positive regulator), phosphorylated AKT (upstream mediator of eNOS phosphorylation on Ser-1177), an NADPH oxidase catalytic subunit gp91(phox), and a marker of oxidative stress (4-hydroxy-2-nonenal [HNE]) were measured by Western blot. Main Outcome Measures Effect of continuous sildenafil treatment on eNOS posttranslational activation, NADPH oxidase catalytic subunit, and oxidative stress in the penis of the sickle cell mouse. Results Continuous treatment with sildenafil reversed (P < 0.05) the abnormalities in protein expressions of P-eNOS (Ser-1177), eNOS/HSP90 interaction, P-AKT, protein expression of gp91(phox), and 4-HNE, in the sickle cell mouse penis. Sildenafil treatment of WT mice did not affect any of these parameters. Conclusion Our findings that sildenafil enhances eNOS activation and inhibits NADPH oxidase function in the sickle cell mouse penis offers a vasculoprotective molecular basis for the therapeutic effect of sildenafil in the penis in association with SCD. PMID:24251665

  5. Sildenafil promotes eNOS activation and inhibits NADPH oxidase in the transgenic sickle cell mouse penis.

    PubMed

    Musicki, Biljana; Bivalacqua, Trinity J; Champion, Hunter C; Burnett, Arthur L

    2014-02-01

    Sickle cell disease (SCD)-associated vasculopathy in the penis is characterized by aberrant nitric oxide and phosphodiesterase (PDE) 5 signaling, and by increased oxidative stress. Preliminary clinical trials show that continuous treatment with PDE5 inhibitor sildenafil unassociated with sexual activity decreases priapic activity in patients with SCD. However, the mechanism of its vasculoprotective effect in the penis remains unclear. We evaluated whether continuous administration of PDE5 inhibitor sildenafil promotes eNOS function at posttranslational levels and decreases superoxide-producing enzyme NADPH oxidase activity in the sickle cell mouse penis. SCD transgenic mice were used as an animal model of SCD. WT mice served as controls. Mice received treatment with the PDE5 inhibitor sildenafil (100 mg/kg/day) or vehicle for 3 weeks. eNOS phosphorylation on Ser-1177 (positive regulatory site), eNOS interactions with heat-shock protein 90 (HSP90) (positive regulator), phosphorylated AKT (upstream mediator of eNOS phosphorylation on Ser-1177), an NADPH oxidase catalytic subunit gp91(phox), and a marker of oxidative stress (4-hydroxy-2-nonenal [HNE]) were measured by Western blot. Effect of continuous sildenafil treatment on eNOS posttranslational activation, NADPH oxidase catalytic subunit, and oxidative stress in the penis of the sickle cell mouse. Continuous treatment with sildenafil reversed (P < 0.05) the abnormalities in protein expressions of P-eNOS (Ser-1177), eNOS/HSP90 interaction, P-AKT, protein expression of gp91(phox), and 4-HNE, in the sickle cell mouse penis. Sildenafil treatment of WT mice did not affect any of these parameters. Our findings that sildenafil enhances eNOS activation and inhibits NADPH oxidase function in the sickle cell mouse penis offers a vasculoprotective molecular basis for the therapeutic effect of sildenafil in the penis in association with SCD. © 2013 International Society for Sexual Medicine.

  6. NADPH oxidases of the brain: distribution, regulation, and function.

    PubMed

    Infanger, David W; Sharma, Ram V; Davisson, Robin L

    2006-01-01

    The NADPH oxidase is a multi-subunit enzyme that catalyzes the reduction of molecular oxygen to form superoxide (O(2)(-)). While classically linked to the respiratory burst in neutrophils, recent evidence now shows that O(2)(-) (and associated reactive oxygen species, ROS) generated by NADPH oxidase in nonphagocytic cells serves myriad functions in health and disease. An entire new family of NADPH Oxidase (Nox) homologues has emerged, which vary widely in cell and tissue distribution, as well as in function and regulation. A major concept in redox signaling is that while NADPH oxidase-derived ROS are necessary for normal cellular function, excessive oxidative stress can contribute to pathological disease. This certainly is true in the central nervous system (CNS), where normal NADPH oxidase function appears to be required for processes such as neuronal signaling, memory, and central cardiovascular homeostasis, but overproduction of ROS contributes to neurotoxicity, neurodegeneration, and cardiovascular diseases. Despite implications of NADPH oxidase in normal and pathological CNS processes, still relatively little is known about the mechanisms involved. This paper summarizes the evidence for NADPH oxidase distribution, regulation, and function in the CNS, emphasizing the diversity of Nox isoforms and their new and emerging role in neuro-cardiovascular function. In addition, perspectives for future research and novel therapeutic targets are offered.

  7. Arginase Inhibition Suppresses Native Low-Density Lipoprotein-Stimulated Vascular Smooth Muscle Cell Proliferation by NADPH Oxidase Inactivation.

    PubMed

    Koo, Bon Hyeock; Yi, Bong Gu; Wang, Wi Kwang; Ko, In Young; Hoe, Kwang Lae; Kwon, Young Guen; Won, Moo Ho; Kim, Young Myeong; Lim, Hyun Kyo; Ryoo, Sungwoo

    2018-05-01

    Vascular smooth muscle cell (VSMC) proliferation induced by native low-density lipoprotein (nLDL) stimulation is dependent on superoxide production from activated NADPH oxidase. The present study aimed to investigate whether the novel arginase inhibitor limonin could suppress nLDL-induced VSMC proliferation and to examine related mechanisms. Isolated VSMCs from rat aortas were treated with nLDL, and cell proliferation was measured by WST-1 and BrdU assays. NADPH oxidase activation was evaluated by lucigenin-induced chemiluminescence, and phosphorylation of protein kinase C (PKC) βII and extracellular signal-regulated kinase (ERK) 1/2 was determined by western blot analysis. Mitochondrial reactive oxygen species (ROS) generation was assessed using MitoSOX-red, and intracellular L-arginine concentrations were determined by high-performance liquid chromatography (HPLC) in the presence or absence of limonin. Limonin inhibited arginase I and II activity in the uncompetitive mode, and prevented nLDL-induced VSMC proliferation in a p21Waf1/Cip1-dependent manner without affecting arginase protein levels. Limonin blocked PKCβII phosphorylation, but not ERK1/2 phosphorylation, and translocation of p47phox to the membrane was decreased, as was superoxide production in nLDL-stimulated VSMCs. Moreover, mitochondrial ROS generation was increased by nLDL stimulation and blocked by preincubation with limonin. Mitochondrial ROS production was responsible for the phosphorylation of PKCβII. HPLC analysis showed that arginase inhibition with limonin increases intracellular L-arginine concentrations, but decreases polyamine concentrations. L-Arginine treatment prevented PKCβII phosphorylation without affecting ERK1/2 phosphorylation. Increased L-arginine levels following limonin-dependent arginase inhibition prohibited NADPH oxidase activation in a PKCβII-dependent manner, and blocked nLDL-stimulated VSMC proliferation. © Copyright: Yonsei University College of Medicine 2018.

  8. Arginase Inhibition Suppresses Native Low-Density Lipoprotein-Stimulated Vascular Smooth Muscle Cell Proliferation by NADPH Oxidase Inactivation

    PubMed Central

    Wang, Wi-Kwang; Ko, In-Young; Hoe, Kwang-Lae; Kwon, Young-Guen; Won, Moo-Ho; Kim, Young-Myeong

    2018-01-01

    Purpose Vascular smooth muscle cell (VSMC) proliferation induced by native low-density lipoprotein (nLDL) stimulation is dependent on superoxide production from activated NADPH oxidase. The present study aimed to investigate whether the novel arginase inhibitor limonin could suppress nLDL-induced VSMC proliferation and to examine related mechanisms. Materials and Methods Isolated VSMCs from rat aortas were treated with nLDL, and cell proliferation was measured by WST-1 and BrdU assays. NADPH oxidase activation was evaluated by lucigenin-induced chemiluminescence, and phosphorylation of protein kinase C (PKC) βII and extracellular signal-regulated kinase (ERK) 1/2 was determined by western blot analysis. Mitochondrial reactive oxygen species (ROS) generation was assessed using MitoSOX-red, and intracellular L-arginine concentrations were determined by high-performance liquid chromatography (HPLC) in the presence or absence of limonin. Results Limonin inhibited arginase I and II activity in the uncompetitive mode, and prevented nLDL-induced VSMC proliferation in a p21Waf1/Cip1-dependent manner without affecting arginase protein levels. Limonin blocked PKCβII phosphorylation, but not ERK1/2 phosphorylation, and translocation of p47phox to the membrane was decreased, as was superoxide production in nLDL-stimulated VSMCs. Moreover, mitochondrial ROS generation was increased by nLDL stimulation and blocked by preincubation with limonin. Mitochondrial ROS production was responsible for the phosphorylation of PKCβII. HPLC analysis showed that arginase inhibition with limonin increases intracellular L-arginine concentrations, but decreases polyamine concentrations. L-Arginine treatment prevented PKCβII phosphorylation without affecting ERK1/2 phosphorylation. Conclusion Increased L-arginine levels following limonin-dependent arginase inhibition prohibited NADPH oxidase activation in a PKCβII-dependent manner, and blocked nLDL-stimulated VSMC proliferation. PMID

  9. NecroX-7 prevents oxidative stress-induced cardiomyopathy by inhibition of NADPH oxidase activity in rats

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

    Park, Joonghoon; Park, Eok; Ahn, Bong-Hyun

    2012-08-15

    Oxidative stress is one of the causes of cardiomyopathy. In the present study, NecroXs, novel class of mitochondrial ROS/RNS scavengers, were evaluated for cardioprotection in in vitro and in vivo model, and the putative mechanism of the cardioprotection of NecroX-7 was investigated by global gene expression profiling and subsequent biochemical analysis. NecroX-7 prevented tert-butyl hydroperoxide (tBHP)-induced death of H9C2 rat cardiomyocytes at EC{sub 50} = 0.057 μM. In doxorubicin (DOX)-induced cardiomyopathy in rats, NecroX-7 significantly reduced the plasma levels of creatine kinase (CK-MB) and lactate dehydrogenase (LDH) which were increased by DOX treatment (p < 0.05). Microarray analysis revealed thatmore » 21 genes differentially expressed in tBHP-treated H9C2 cells were involved in ‘Production of reactive oxygen species’ (p = 0.022), and they were resolved by concurrent NecroX-7 treatment. Gene-to-gene networking also identified that NecroX-7 relieved cell death through Ncf1/p47phox and Rac2 modulation. In subsequent biochemical analysis, NecroX-7 inhibited NADPH oxidase (NOX) activity by 53.3% (p < 0.001). These findings demonstrate that NecroX-7, in part, provides substantial protection of cardiomyopathy induced by tBHP or DOX via NOX-mediated cell death. -- Highlights: ► NecroX-7 prevented tert-butyl hydroperoxide-induced in vitro cardiac cell death. ► NecroX-7 ameliorated doxorubicin-induced in vivo cardiomyopathy. ► NecroX-7 prevented oxidative stress and necrosis-enriched transcriptional changes. ► NecroX-7 effectively inhibited NADPH oxidase activation. ► Cardioprotection of Necro-7 was brought on by modulation of NADPH oxidase activity.« less

  10. Hypoglycemic neuronal death is triggered by glucose reperfusion and activation of neuronal NADPH oxidase

    PubMed Central

    Suh, Sang Won; Gum, Elizabeth T.; Hamby, Aaron M.; Chan, Pak H.; Swanson, Raymond A.

    2007-01-01

    Hypoglycemic coma and brain injury are potential complications of insulin therapy. Certain neurons in the hippocampus and cerebral cortex are uniquely vulnerable to hypoglycemic cell death, and oxidative stress is a key event in this cell death process. Here we show that hypoglycemia-induced oxidative stress and neuronal death are attributable primarily to the activation of neuronal NADPH oxidase during glucose reperfusion. Superoxide production and neuronal death were blocked by the NADPH oxidase inhibitor apocynin in both cell culture and in vivo models of insulin-induced hypoglycemia. Superoxide production and neuronal death were also blocked in studies using mice or cultured neurons deficient in the p47phox subunit of NADPH oxidase. Chelation of zinc with calcium disodium EDTA blocked both the assembly of the neuronal NADPH oxidase complex and superoxide production. Inhibition of the hexose monophosphate shunt, which utilizes glucose to regenerate NADPH, also prevented superoxide formation and neuronal death, suggesting a mechanism linking glucose reperfusion to superoxide formation. Moreover, the degree of superoxide production and neuronal death increased with increasing glucose concentrations during the reperfusion period. These results suggest that high blood glucose concentrations following hypoglycemic coma can initiate neuronal death by a mechanism involving extracellular zinc release and activation of neuronal NADPH oxidase. PMID:17404617

  11. Neovascularization in an arterio-venous loop-containing tissue engineering chamber: role of NADPH oxidase

    PubMed Central

    Jiang, F; Zhang, G; Hashimoto, I; Kumar, B S; Bortolotto, S; Morrison, W A; Dusting, G J

    2008-01-01

    Using an in vivo arterio-venous loop-containing tissue-engineering chamber, we have created a variety of vascularized tissue blocks, including functional myocardium. The viability of the transplanted cells is limited by the rate of neovascularization in the chamber. A Nox2-containing nicotinamide adenine dinucleotide phosphate (NADPH) oxidase is thought to have a critical role in ischaemic angiogenesis. In this study we investigated whether NADPH oxidase is involved in the neovascularization process in the tissue-engineering chamber. New blood vessels originating from the venous and the arterial ends of the loop could be identified after 3 days, and the vessel density (by lectin staining) peaked after 7 days and was maintained for at least 14 days. This was accompanied by granulation tissue formation and concomitant increase in the mRNA level of Nox4 NADPH oxidase. Although the total level of Nox2 mRNA in the chamber tissue decreased from day 3 to day 7, immunohistochemistry identified a strong expression of Nox2 in the endothelial cells of the new vessels. In human microvascular endothelial cells, the NADPH oxidase inhibitor apocynin reduced NADPH oxidase activity and inhibited the angiogenic responses in vitro. Local treatment with the NADPH oxidase inhibitors apocynin or gp91ds-tat peptide significantly suppressed the vessel growth in the chamber. In conclusion, NADPH oxidase-dependent redox signalling is important for neovascularization in this novel tissue-engineering chamber in vivo, and boosting this signalling might be a new approach to extending vascularization and tissue growth. PMID:19012731

  12. Selective Rac1 inhibition protects renal tubular epithelial cells from oxalate-induced NADPH oxidase-mediated oxidative cell injury

    PubMed Central

    Thamilselvan, Vijayalakshmi; Menon, Mani

    2013-01-01

    Oxalate-induced oxidative cell injury is one of the major mechanisms implicated in calcium oxalate nucleation, aggregation and growth of kidney stones. We previously demonstrated that oxalate-induced NADPH oxidase-derived free radicals play a significant role in renal injury. Since NADPH oxidase activation requires several regulatory proteins, the primary goal of this study was to characterize the role of Rac GTPase in oxalate-induced NADPH oxidase-mediated oxidative injury in renal epithelial cells. Our results show that oxalate significantly increased membrane translocation of Rac1 and NADPH oxidase activity of renal epithelial cells in a time-dependent manner. We found that NSC23766, a selective inhibitor of Rac1, blocked oxalate-induced membrane translocation of Rac1 and NADPH oxidase activity. In the absence of Rac1 inhibitor, oxalate exposure significantly increased hydrogen peroxide formation and LDH release in renal epithelial cells. In contrast, Rac1 inhibitor pretreatment, significantly decreased oxalate-induced hydrogen peroxide production and LDH release. Furthermore, PKC α and δ inhibitor, oxalate exposure did not increase Rac1 protein translocation, suggesting that PKC resides upstream from Rac1 in the pathway that regulates NADPH oxidase. In conclusion, our data demonstrate for the first time that Rac1-dependent activation of NADPH oxidase might be a crucial mechanism responsible for oxalate-induced oxidative renal cell injury. These findings suggest that Rac1 signaling plays a key role in oxalate-induced renal injury, and may serve as a potential therapeutic target to prevent calcium oxalate crystal deposition in stone formers and reduce recurrence. PMID:21814770

  13. Targeting NADPH oxidase decreases oxidative stress in the transgenic sickle cell mouse penis.

    PubMed

    Musicki, Biljana; Liu, Tongyun; Sezen, Sena F; Burnett, Arthur L

    2012-08-01

    Sickle cell disease (SCD) is a state of chronic vasculopathy characterized by endothelial dysfunction and increased oxidative stress, but the sources and mechanisms responsible for reactive oxygen species (ROS) production in the penis are unknown. We evaluated whether SCD activates NADPH oxidase, induces endothelial nitric oxide synthase (eNOS) uncoupling, and decreases antioxidants in the SCD mouse penis. We further tested the hypothesis that targeting NADPH oxidase decreases oxidative stress in the SCD mouse penis. SCD transgenic (sickle) mice were used as an animal model of SCD. Hemizygous (hemi) mice served as controls. Mice received an NADPH oxidase inhibitor apocynin (10 mM in drinking water) or vehicle. Penes were excised at baseline for molecular studies. Markers of oxidative stress (4-hydroxy-2-nonenal [HNE]), sources of ROS (eNOS uncoupling and NADPH oxidase subunits p67(phox) , p47(phox) , and gp91(phox) ), and enzymatic antioxidants (superoxide dismutase [SOD]1, SOD2, catalase, and glutathione peroxidase-1 [GPx1]) were measured by Western blot in penes. Sources of ROS, oxidative stress, and enzymatic antioxidants in the SCD penis. Relative to hemi mice, SCD increased (P<0.05) protein expression of NADPH oxidase subunits p67(phox) , p47(phox) , and gp91(phox) , 4-HNE-modified proteins, induced eNOS uncoupling, and reduced Gpx1 expression in the penis. Apocynin treatment of sickle mice reversed (P<0.05) the abnormalities in protein expressions of p47(phox) , gp91(phox) (but not p67(phox) ) and 4-HNE, but only slightly (P>0.05) prevented eNOS uncoupling in the penis. Apocynin treatment of hemi mice did not affect any of these parameters. NADPH oxidase and eNOS uncoupling are sources of oxidative stress in the SCD penis; decreased GPx1 further contributes to oxidative stress. Inhibition of NADPH oxidase upregulation decreases oxidative stress, implying a major role for NADPH oxidase as a ROS source and a potential target for improving vascular function in

  14. Targeting NADPH Oxidase Decreases Oxidative Stress in the Transgenic Sickle Cell Mouse Penis

    PubMed Central

    Musicki, Biljana; Liu, Tongyun; Sezen, Sena F.; Burnett, Arthur L.

    2012-01-01

    Introduction Sickle cell disease (SCD) is a state of chronic vasculopathy characterized by endothelial dysfunction and increased oxidative stress, but the sources and mechanisms responsible for reactive oxygen species (ROS) production in the penis are unknown. Aims We evaluated whether SCD activates NADPH oxidase, induces endothelial nitric oxide synthase (eNOS) uncoupling, and decreases antioxidants in the SCD mouse penis. We further tested the hypothesis that targeting NADPH oxidase decreases oxidative stress in the SCD mouse penis. Methods SCD transgenic (sickle) mice were used as an animal model of SCD. Hemizygous (hemi) mice served as controls. Mice received an NADPH oxidase inhibitor apocynin (10 mM in drinking water) or vehicle. Penes were excised at baseline for molecular studies. Markers of oxidative stress (4-hydroxy-2-nonenal [HNE]), sources of ROS (eNOS uncoupling and NADPH oxidase subunits p67phox, p47phox, and gp91phox), and enzymatic antioxidants (superoxide dismutase [SOD]1, SOD2, catalase, and glutathione peroxidase-1 [GPx1]) were measured by Western blot in penes. Main Outcome Measures Sources of ROS, oxidative stress, and enzymatic antioxidants in the SCD penis. Results Relative to hemi mice, SCD increased (P < 0.05) protein expression of NADPH oxidase subunits p67phox, p47phox, and gp91phox, 4-HNE-modified proteins, induced eNOS uncoupling, and reduced Gpx1 expression in the penis. Apocynin treatment of sickle mice reversed (P < 0.05) the abnormalities in protein expressions of p47phox, gp91phox (but not p67phox) and 4-HNE, but only slightly (P > 0.05) prevented eNOS uncoupling in the penis. Apocynin treatment of hemi mice did not affect any of these parameters. Conclusion NADPH oxidase and eNOS uncoupling are sources of oxidative stress in the SCD penis; decreased GPx1 further contributes to oxidative stress. Inhibition of NADPH oxidase upregulation decreases oxidative stress, implying a major role for NADPH oxidase as a ROS source and a

  15. Reconstituted high-density lipoprotein suppresses leukocyte NADPH oxidase activation by disrupting lipid rafts.

    PubMed

    Peshavariya, Hitesh; Dusting, Gregory J; Di Bartolo, Belinda; Rye, Kerry-Anne; Barter, Philip J; Jiang, Fan

    2009-08-01

    Reconstituted discoidal high-density lipoprotein (rHDL) has potent vascular protective actions. Native HDL suppresses cellular generation of reactive oxygen species, whereas this antioxidant effect of rHDL is less clear. This study examined the effects of rHDL on NADPH oxidase, a major source of cellular superoxide generation, in both leukocytes and human umbilical vein endothelial cells. Superoxide was measured with lucigenin-enhanced chemiluminescence. Expression of NADPH oxidase sub-units was determined by real-time PCR. Pre-treatment of HL-60 cells with rHDL (10 and 25 microM) for 1 h significantly reduced phorbol 12-myristate 13-acetate-stimulated superoxide production. Treatment with rHDL for up to 24 h did not change the mRNA expression of NADPH oxidase sub-units. In HL-60 cells, depletion of cholesterol from the plasma membrane by methyl-beta-cyclodextrin mimicked the effect of rHDL, whereas cholesterol repletion blunted the effects of rHDL. Treatment with rHDL induced disruption of the lipid raft structures and blunted PMA-induced redistribution of p47phox into lipid rafts. In contrast, treatment of endothelial cells with rHDL for up to 18 h had no effect on either basal or tumour necrosis factor-alpha-stimulated NADPH oxidase activity, but markedly suppressed the cytokine-induced expression of proinflammatory adhesion molecules. The results suggest that rHDL inhibits NADPH oxidase activation in leukocytes, probably by interrupting the assembly of NADPH oxidase sub-units at the lipid rafts. This effect may contribute to the vascular protective actions of rHDL against inflammation-mediated oxidative damage.

  16. Activation of NADPH oxidase mediates increased endoplasmic reticulum stress and left ventricular remodeling after myocardial infarction in rabbits.

    PubMed

    Li, Bao; Tian, Jing; Sun, Yi; Xu, Tao-Rui; Chi, Rui-Fang; Zhang, Xiao-Li; Hu, Xin-Ling; Zhang, Yue-An; Qin, Fu-Zhong; Zhang, Wei-Fang

    2015-05-01

    Nicotinamide adenine dinucleotide 3-phosphate (NADPH) oxidase activity and endoplasmic reticulum (ER) stress are increased after myocardial infarction (MI). In this study, we proposed to test whether activation of the NADPH oxidase in the remote non-infarcted myocardium mediates ER stress and left ventricular (LV) remodeling after MI. Rabbits with MI or sham operation were randomly assigned to orally receive an NADPH oxidase inhibitor apocynin or placebo for 30 days. The agents were administered beginning at 1 week after surgery. MI rabbits exhibited decreases in LV fractional shortening, LV ejection fraction and the first derivative of the LV pressure rise, which were abolished by apocynin treatment. NADPH oxidase Nox2 protein and mRNA expressions were increased in the remote non-infarcted myocardium after MI. Immunolabeling further revealed that Nox2 was increased in cardiac myocytes in the remote myocardium. The apocynin treatment prevented increases in the Nox2 expression, NADPH oxidase activity, oxidative stress, myocyte apoptosis and GRP78, CHOP and cleaved caspase 12 protein expression in the remote myocardium. The apocynin treatment also attenuated increases in myocyte diameter and cardiac fibrosis. In cultured H9C2 cardiomyocytes exposed to angiotensin II, an important stimulus for post-MI remodeling, Nox2 knockdown with siRNA significantly inhibited angiotensin II-induced NADPH oxidase activation, reactive oxygen species and GRP78 and CHOP protein expression. We conclude that NADPH oxidase inhibition attenuates increased ER stress in the remote non-infarcted myocardium and LV remodeling late after MI in rabbits. These findings suggest that the activation of NADPH oxidase in the remote non-infarcted myocardium mediates increased ER stress, contributing to myocyte apoptosis and LV remodeling after MI. Copyright © 2015 Elsevier B.V. All rights reserved.

  17. Attenuation of NADPH oxidase activation and glomerular filtration barrier remodeling with statin treatment.

    PubMed

    Whaley-Connell, Adam; Habibi, Javad; Nistala, Ravi; Cooper, Shawna A; Karuparthi, Poorna R; Hayden, Melvin R; Rehmer, Nathan; DeMarco, Vincent G; Andresen, Bradley T; Wei, Yongzhong; Ferrario, Carlos; Sowers, James R

    2008-02-01

    Activation of reduced nicotinamide-adenine dinucleotide phosphate (NADPH) oxidase by angiotensin II is integral to the formation of oxidative stress in the vasculature and the kidney. 3-Hydroxy-3-methylglutaryl-coenzyme A reductase inhibition is associated with reductions of oxidative stress in the vasculature and kidney and associated decreases in albuminuria. Effects of 3-hydroxy-3-methylglutaryl-coenzyme A reductase inhibition on oxidative stress in the kidney and filtration barrier integrity are poorly understood. To investigate, we used transgenic TG(mRen2)27 (Ren2) rats, which harbor the mouse renin transgene and renin-angiotensin system activation, and an immortalized murine podocyte cell line. We treated young, male Ren2 and Sprague-Dawley rats with rosuvastatin (20 mg/kg IP) or placebo for 21 days. Compared with controls, we observed increases in systolic blood pressure, albuminuria, renal NADPH oxidase activity, and 3-nitrotryosine staining, with reductions in the rosuvastatin-treated Ren2. Structural changes on light and transmission electron microscopy, consistent with periarteriolar fibrosis and podocyte foot-process effacement, were attenuated with statin treatment. Nephrin expression was diminished in the Ren2 kidney and trended to normalize with statin treatment. Angiotensin II-dependent increases in podocyte NADPH oxidase activity and subunit expression (NOX2, NOX4, Rac, and p22(phox)) and reactive oxygen species generation were decreased after in vitro statin treatment. These data support a role for increased NADPH oxidase activity and subunit expression with resultant reactive oxygen species formation in the kidney and podocyte. Furthermore, statin attenuation of NADPH oxidase activation and reactive oxygen species formation in the kidney/podocyte seems to play roles in the abrogation of oxidative stress-induced filtration barrier injury and consequent albuminuria.

  18. Exploiting algal NADPH oxidase for biophotovoltaic energy

    DOE PAGES

    Anderson, Alexander; Laohavisit, Anuphon; Blaby, Ian K.; ...

    2015-01-29

    Photosynthetic microbes exhibit light-dependent electron export across the cell membrane, which can generate electricity in biological photovoltaic (BPV) devices. How electrons are exported remains to be determined; the identification of mechanisms would help selection or generation of photosynthetic microbes capable of enhanced electrical output. We show that plasma membrane NADPH oxidase activity is a significant component of light-dependent generation of electricity by the unicellular green alga Chlamydomonas reinhardtii. NADPH oxidases export electrons across the plasma membrane to form superoxide anion from oxygen. The C. reinhardtii mutant lacking the NADPH oxidase encoded by RBO1 is impaired in both extracellular superoxide anionmore » production and current generation in a BPV device. Complementation with the wild-type gene restores both capacities, demonstrating the role of the enzyme in electron export. Monitoring light-dependent extracellular superoxide production with a colorimetric assay is shown to be an effective way of screening for electrogenic potential of candidate algal strains. Furthermore, the results show that algal NADPH oxidases are important for superoxide anion production and open avenues for optimizing the biological component of these devices.« less

  19. NADPH oxidases: novel therapeutic targets for neurodegenerative diseases.

    PubMed

    Gao, Hui-Ming; Zhou, Hui; Hong, Jau-Shyong

    2012-06-01

    Oxidative stress is a key pathologic factor in neurodegenerative diseases such as Alzheimer and Parkinson diseases (AD, PD). The failure of free-radical-scavenging antioxidants in clinical trials pinpoints an urgent need to identify and to block major sources of oxidative stress in neurodegenerative diseases. As a major superoxide-producing enzyme complex in activated phagocytes, phagocyte NADPH oxidase (PHOX) is essential for host defense. However, recent preclinical evidence has underscored a pivotal role of overactivated PHOX in chronic neuroinflammation and progressive neurodegeneration. Deficiency in PHOX subunits mitigates neuronal damage induced by diverse insults/stresses relevant to neurodegenerative diseases. More importantly, suppression of PHOX activity correlates with reduced neuronal impairment in models of neurodegenerative diseases. The discovery of PHOX and non-phagocyte NADPH oxidases in astroglia and neurons further reinforces the crucial role of NADPH oxidases in oxidative stress-mediated chronic neurodegeneration. Thus, proper modulation of NADPH oxidase activity might hold therapeutic potential for currently incurable neurodegenerative diseases. Published by Elsevier Ltd.

  20. Dexamethasone but not indomethacin inhibits human phagocyte nicotinamide adenine dinucleotide phosphate oxidase activity by down-regulating expression of genes encoding oxidase components.

    PubMed

    Condino-Neto, A; Whitney, C; Newburger, P E

    1998-11-01

    We investigated the effects of dexamethasone or indomethacin on the NADPH oxidase activity, cytochrome b558 content, and expression of genes encoding the components gp91-phox and p47-phox of the NADPH oxidase system in the human monocytic THP-1 cell line, differentiated with IFN-gamma and TNF-alpha, alone or in combination, for up to 7 days. IFN-gamma and TNF-alpha, alone or in combination, caused a significant up-regulation of the NADPH oxidase system as reflected by an enhancement of the PMA-stimulated superoxide release, cytochrome b558 content, and expression of gp91-phox and p47-phox genes on both days 2 and 7 of cell culture. Noteworthy was the tremendous synergism between IFN-gamma and TNF-alpha for all studied parameters. Dexamethasone down-regulated the NADPH oxidase system of cytokine-differentiated THP-1 cells as assessed by an inhibition on the PMA-stimulated superoxide release, cytochrome b558 content, and expression of the gp91-phox and p47-phox genes. The nuclear run-on assays indicated that dexamethasone down-regulated the NADPH oxidase system at least in part by inhibiting the transcription of gp91-phox and p47-phox genes. Indomethacin inhibited only the PMA-stimulated superoxide release of THP-1 cells differentiated with IFN-gamma and TNF-alpha during 7 days. None of the other parameters was affected by indomethacin. We conclude that dexamethasone down-regulates the NADPH oxidase system at least in part by inhibiting the expression of genes encoding the gp91-phox and p47-phox components of the NADPH oxidase system.

  1. NADPH OXIDASE: STRUCTURE AND ACTIVATION MECHANISMS (REVIEW). NOTE I.

    PubMed

    Filip-Ciubotaru, Florina; Manciuc, Carmen; Stoleriu, Gabriela; Foia, Liliana

    2016-01-01

    NADPH oxidase (nicotinamide adenine dinucleotide phosphate-oxidase), with its generically termed NOX isoforms, is the major source of ROS (reactive oxigen species) in biological systems. ROS are small oxygen-derived molecules with an important role in various biological processes (physiological or pathological). If under physiological conditions some processes are beneficial and necessary for life, under pathophysiological conditions they are noxious, harmful. NADPH oxidases are present in phagocytes and in a wide variety of nonphagocytic cells. The enzyme generates superoxide by transferring electrons from NADPH inside the cell across the membrane and coupling them to molecular oxygen to produce superoxide anion, a reactive free-radical. Structurally, NADPH oxidase is a multicomponent enzyme which includes two integral membrane proteins, glycoprotein gp9 1 Phox and adaptor protein p22(phox), which together form the heterodimeric flavocytochrome b558 that constitutes the core of the enzyme. During the resting state, the multidomain regulatory subunits p40P(phox), p47(phox), p67(Phox) are located in the cytosol organized as a complex. The activation of phagocytic NADPH oxidase occurs through a complex series of protein interactions.

  2. Astragaloside IV prevents damage to human mesangial cells through the inhibition of the NADPH oxidase/ROS/Akt/NF‑κB pathway under high glucose conditions.

    PubMed

    Sun, Li; Li, Weiping; Li, Weizu; Xiong, Li; Li, Guiping; Ma, Rong

    2014-07-01

    Glomerular hypertrophy and hyperfiltration are the two major pathological characteristics of the early stages of diabetic nephropathy (DN), which are respectively related to mesangial cell (MC) proliferation and a decrease in calcium influx conducted by canonical transient receptor potential cation channel 6 (TRPC6). The marked increase in the production of reactive oxygen species (ROS) induced by hyperglycemia is the main sponsor of multiple pathological pathways in DN. Nicotinamide adenine dinucleotide phosphate (NADPH) oxidase is an important source of ROS production in MCs. Astragaloside IV (AS‑IV) is an active ingredient of Radix Astragali which has a potent antioxidative effect. In this study, we aimed to investigate whether high glucose (HG)‑induced NADPH oxidase activation and ROS production contribute to MC proliferation and the downregulation of TRPC6 expression; we also wished to determine the effects of AS‑IV on MCs under HG conditions. Using a human glomerular mesangial cell line, we found that treatment with AS‑IV for 48 h markedly attenuated HG‑induced proliferation and the hypertrophy of MCs in a dose‑dependent manner. The intracellular ROS level was also markedly reduced following treatment with AS‑IV. In addition, the enhanced activity of NADPH oxidase and the expression level of NADPH oxidase 4 (Nox4) protein were decreased. Treatment with AS‑IV also inhibited the phosphorylation level of Akt and IκBα in the MCs. In addition, TRPC6 protein expression and the intracellular free calcium concentration were also markedly reduced following treatment with AS‑IV under HG conditions. These results suggest that AS‑IV inhibits HG‑induced mesangial cell proliferation and glomerular contractile dysfunction through the NADPH oxidase/ROS/Akt/nuclear factor‑κB (NF‑κB) pathway, providing a new perspective for the clinical treatment of DN.

  3. Myeloperoxidase amplified high glucose-induced endothelial dysfunction in vasculature: Role of NADPH oxidase and hypochlorous acid.

    PubMed

    Tian, Rong; Ding, Yun; Peng, Yi-Yuan; Lu, Naihao

    2017-03-11

    Nicotinamide adenine dinucleotide phosphate (NADPH) oxidase-derived reactive oxygen species (ROS) such as superoxide and hydrogen peroxide (H 2 O 2 ), have emerged as important molecules in the pathogenesis of diabetic endothelial dysfunction. Additionally, neutrophils-derived myeloperoxidase (MPO) and MPO-catalyzed hypochlorous acid (HOCl) play important roles in the vascular injury. However, it is unknown whether MPO can use vascular-derived ROS to induce diabetic endothelial dysfunction. In the present study, we demonstrated that NADPH oxidase was the main source of ROS formation in high glucose-cultured human umbilical vein endothelial cells (HUVECs), and played a critical role in high glucose-induced endothelial dysfunction such as cell apoptosis, loss of cell viability and reduction of nitric oxide (NO). However, the addition of MPO could amplify the high glucose-induced endothelial dysfunction which was inhibited by the presence of apocynin (NADPH oxidase inhibitor), catalase (H 2 O 2 scavenger), or methionine (HOCl scavenger), demonstrating the contribution of NADPH oxidase-H 2 O 2 -MPO-HOCl pathway in the MPO/high glucose-induced vascular injury. In high glucose-incubated rat aortas, MPO also exacerbated the NADPH oxidase-induced impairment of endothelium-dependent relaxation. Consistent with these in vitro data, in diabetic rat aortas, both MPO expresion and NADPH oxidase activity were increased while the endothelial function was simultaneously impaired. The results suggested that vascular-bound MPO could amplify high glucose-induced vascular injury in diabetes. MPO-NADPH oxidase-HOCl may represent an important pathogenic pathway in diabetic vascular diseases. Copyright © 2017 Elsevier Inc. All rights reserved.

  4. Phosphatidic acid as a second messenger in human polymorphonuclear leukocytes. Effects on activation of NADPH oxidase.

    PubMed Central

    Agwu, D E; McPhail, L C; Sozzani, S; Bass, D A; McCall, C E

    1991-01-01

    Receptor-mediated agonists, such as FMLP, induce an early, phospholipase D (PLD)-mediated accumulation of phosphatidic acid (PA) which may play a role in the activation of NADPH oxidase in human PMN. We have determined the effect of changes in PA production on O2 consumption in intact PMN and the level of NADPH oxidase activity measured in a cell-free assay. Pretreatment of cells with various concentrations of propranolol enhanced (less than or equal to 200 microM) or inhibited (greater than 300 microM) PLD-induced production of PA (mass and radiolabel) in a manner that correlated with enhancement or inhibition of O2 consumption in PMN stimulated with 1 microM FMLP in the absence of cytochalasin B. The concentration-dependent effects of propranolol on FMLP-induced NADPH oxidase activation was confirmed by direct assay of the enzyme in subcellular fractions. In PA extracted from cells pretreated with 200 microM propranolol before stimulation with 1 microM FMLP, phospholipase A1 (PLA1)-digestion for 90 min, followed by quantitation of residual PA, showed that a minimum of 44% of PA in control (undigested) sample was diacyl-PA; alkylacyl-PA remained undigested by PLA1. Propranolol was also observed to have a concentration-dependent enhancement of mass of 1,2-DG formed in PMN stimulated with FMLP. DG levels reached a maximum at 300 microM propranolol and remained unchanged up to 500 microM propranolol. However, in contrast to PA levels, the level of DG produced did not correlate with NADPH oxidase activation. Exogenously added didecanoyl-PA activated NADPH oxidase in a concentration-dependent manner (1-300 microM) in a reconstitution assay using membrane and cytosolic fractions from unstimulated PMN. In addition, PA synergized with SDS for oxidase activation. Taken together, these results indicate that PA plays a second messenger role in the activation of NADPH oxidase in human PMN and that regulation of phospholipase D is a key step in the activation pathway. Images

  5. Evolution of NADPH Oxidase Inhibitors: Selectivity and Mechanisms for Target Engagement.

    PubMed

    Altenhöfer, Sebastian; Radermacher, Kim A; Kleikers, Pamela W M; Wingler, Kirstin; Schmidt, Harald H H W

    2015-08-10

    Oxidative stress, an excess of reactive oxygen species (ROS) production versus consumption, may be involved in the pathogenesis of different diseases. The only known enzymes solely dedicated to ROS generation are nicotinamide adenine dinucleotide phosphate (NADPH) oxidases with their catalytic subunits (NOX). After the clinical failure of most antioxidant trials, NOX inhibitors are the most promising therapeutic option for diseases associated with oxidative stress. Historical NADPH oxidase inhibitors, apocynin and diphenylene iodonium, are un-specific and not isoform selective. Novel NOX inhibitors stemming from rational drug discovery approaches, for example, GKT137831, ML171, and VAS2870, show improved specificity for NADPH oxidases and moderate NOX isoform selectivity. Along with NOX2 docking sequence (NOX2ds)-tat, a peptide-based inhibitor, the use of these novel small molecules in animal models has provided preliminary in vivo evidence for a pathophysiological role of specific NOX isoforms. Here, we discuss whether novel NOX inhibitors enable reliable validation of NOX isoforms' pathological roles and whether this knowledge supports translation into pharmacological applications. Modern NOX inhibitors have increased the evidence for pathophysiological roles of NADPH oxidases. However, in comparison to knockout mouse models, NOX inhibitors have limited isoform selectivity. Thus, their use does not enable clear statements on the involvement of individual NOX isoforms in a given disease. The development of isoform-selective NOX inhibitors and biologicals will enable reliable validation of specific NOX isoforms in disease models other than the mouse. Finally, GKT137831, the first NOX inhibitor in clinical development, is poised to provide proof of principle for the clinical potential of NOX inhibition.

  6. NADPH oxidase-mediated redox signaling promotes oxidative stress resistance and longevity through memo-1 in C. elegans

    PubMed Central

    Ewald, Collin Yvès; Hourihan, John M; Bland, Monet S; Obieglo, Carolin; Katic, Iskra; Moronetti Mazzeo, Lorenza E; Alcedo, Joy; Blackwell, T Keith; Hynes, Nancy E

    2017-01-01

    Transient increases in mitochondrially-derived reactive oxygen species (ROS) activate an adaptive stress response to promote longevity. Nicotinamide adenine dinucleotide phosphate (NADPH) oxidases produce ROS locally in response to various stimuli, and thereby regulate many cellular processes, but their role in aging remains unexplored. Here, we identified the C. elegans orthologue of mammalian mediator of ErbB2-driven cell motility, MEMO-1, as a protein that inhibits BLI-3/NADPH oxidase. MEMO-1 is complexed with RHO-1/RhoA/GTPase and loss of memo-1 results in an enhanced interaction of RHO-1 with BLI-3/NADPH oxidase, thereby stimulating ROS production that signal via p38 MAP kinase to the transcription factor SKN-1/NRF1,2,3 to promote stress resistance and longevity. Either loss of memo-1 or increasing BLI-3/NADPH oxidase activity by overexpression is sufficient to increase lifespan. Together, these findings demonstrate that NADPH oxidase-induced redox signaling initiates a transcriptional response that protects the cell and organism, and can promote both stress resistance and longevity. DOI: http://dx.doi.org/10.7554/eLife.19493.001 PMID:28085666

  7. [Oxygen and the superoxide anion. Modulation of NADPH oxidase?].

    PubMed

    Delbosc, S; Cristol, J P; Descomps, B; Chénard, J; Sirois, P

    2001-01-01

    Oxidative stress which results from an imbalance between oxidant production and antioxidant defense mechanisms can promote modifications of lipids, proteins and nucleic acids. This review focuses on the different pathways leading to Reactive Oxygen Species (ROS) production in particular on NADPH oxidase activation. This enzyme is localized in numerous cells including phagocytes and vascular cells and composed of membrane and cytosolic sub-units. The activation of the NADPH oxidase is largely involved in inflammation associated diseases such as asthma, Systemic Inflammatory Response Syndrome and aging associated diseases such as atherosclerosis and neurodeneratives diseases. The modulation of NADPH oxidase could be a way to limit or prevent the development of these diseases.

  8. Ultrafine carbon particles promote rotenone-induced dopamine neuronal loss through activating microglial NADPH oxidase

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

    Wang, Yinxi; Liu, Dan; Zhang, Huifeng

    Background: Atmospheric ultrafine particles (UFPs) and pesticide rotenone were considered as potential environmental risk factors for Parkinson's disease (PD). However, whether and how UFPs alone and in combination with rotenone affect the pathogenesis of PD remains largely unknown. Methods: Ultrafine carbon black (ufCB, a surrogate of UFPs) and rotenone were used individually or in combination to determine their roles in chronic dopaminergic (DA) loss in neuron-glia, and neuron-enriched, mix-glia cultures. Immunochemistry using antibody against tyrosine hydroxylase was performed to detect DA neuronal loss. Measurement of extracellular superoxide and intracellular reactive oxygen species (ROS) were performed to examine activation of NADPHmore » oxidase. Genetic deletion and pharmacological inhibition of NADPH oxidase and MAC-1 receptor in microglia were employed to examine their role in DA neuronal loss triggered by ufCB and rotenone. Results: In rodent midbrain neuron-glia cultures, ufCB and rotenone alone caused neuronal death in a dose-dependent manner. In particularly, ufCB at doses of 50 and 100 μg/cm{sup 2} induced significant loss of DA neurons. More importantly, nontoxic doses of ufCB (10 μg/cm{sup 2}) and rotenone (2 nM) induced synergistic toxicity to DA neurons. Microglial activation was essential in this process. Furthermore, superoxide production from microglial NADPH oxidase was critical in ufCB/rotenone-induced neurotoxicity. Studies in mix-glia cultures showed that ufCB treatment activated microglial NADPH oxidase to induce superoxide production. Firstly, ufCB enhanced the expression of NADPH oxidase subunits (gp91{sup phox}, p47{sup phox} and p40{sup phox}); secondly, ufCB was recognized by microglial surface MAC-1 receptor and consequently promoted rotenone-induced p47{sup phox} and p67{sup phox} translocation assembling active NADPH oxidase. Conclusion: ufCB and rotenone worked in synergy to activate NADPH oxidase in microglia, leading to

  9. Calcium mobilization and Rac1 activation are required for VCAM-1 (vascular cell adhesion molecule-1) stimulation of NADPH oxidase activity.

    PubMed Central

    Cook-Mills, Joan M; Johnson, Jacob D; Deem, Tracy L; Ochi, Atsuo; Wang, Lei; Zheng, Yi

    2004-01-01

    VCAM-1 (vascular cell adhesion molecule-1) plays an important role in the regulation of inflammation in atherosclerosis, asthma, inflammatory bowel disease and transplantation. VCAM-1 activates endothelial cell NADPH oxidase, and this oxidase activity is required for VCAM-1-dependent lymphocyte migration. We reported previously that a mouse microvascular endothelial cell line promotes lymphocyte migration that is dependent on VCAM-1, but not on other known adhesion molecules. Here we have investigated the signalling mechanisms underlying VCAM-1 function. Lymphocyte binding to VCAM-1 on the endothelial cell surface activated an endothelial cell calcium flux that could be inhibited with anti-alpha4-integrin and mimicked by anti-VCAM-1-coated beads. VCAM-1 stimulation of calcium responses could be blocked by an inhibitor of intracellular calcium mobilization, a calcium channel inhibitor or a calcium chelator, resulting in the inhibition of NADPH oxidase activity. Addition of ionomycin overcame the calcium channel blocker suppression of VCAM-1-stimulated NADPH oxidase activity, but could not reverse the inhibitory effect imposed by intracellular calcium blockage, indicating that both intracellular and extracellular calcium mobilization are required for VCAM-1-mediated activation of NADPH oxidase. Furthermore, VCAM-1 specifically activated the Rho-family GTPase Rac1, and VCAM-1 activation of NADPH oxidase was blocked by a dominant negative Rac1. Thus VCAM-1 stimulates the mobilization of intracellular and extracellular calcium and Rac1 activity that are required for the activation of NADPH oxidase. PMID:14594451

  10. NADPH Oxidase Activation Contributes to Heavy Ion Irradiation–Induced Cell Death

    PubMed Central

    Wang, Yupei; Liu, Qing; Zhao, Weiping; Zhou, Xin; Miao, Guoying; Sun, Chao

    2017-01-01

    Increased oxidative stress plays an important role in heavy ion radiation–induced cell death. The mechanism involved in the generation of elevated reactive oxygen species (ROS) is not fully illustrated. Here we show that NADPH oxidase activation is closely related to heavy ion radiation–induced cell death via excessive ROS generation. Cell death and cellular ROS can be greatly reduced in irradiated cancer cells with the preincubation of diphenyleneiodium, an inhibitor of NADPH oxidase. Most of the NADPH oxidase (NOX) family proteins (NOX1, NOX2, NOX3, NOX4, and NOX5) showed increased expression after heavy ion irradiation. Meanwhile, the cytoplasmic subunit p47phox was translocated to the cell membrane and localized with NOX2 to form reactive NADPH oxidase. Our data suggest for the first time that ROS generation, as mediated by NADPH oxidase activation, could be an important contributor to heavy ion irradiation–induced cell death. PMID:28473742

  11. Micro-RNA 21 inhibition of SMAD7 enhances fibrogenesis via leptin-mediated NADPH oxidase in experimental and human nonalcoholic steatohepatitis.

    PubMed

    Dattaroy, Diptadip; Pourhoseini, Sahar; Das, Suvarthi; Alhasson, Firas; Seth, Ratanesh Kumar; Nagarkatti, Mitzi; Michelotti, Gregory A; Diehl, Anna Mae; Chatterjee, Saurabh

    2015-02-15

    Hepatic fibrosis in nonalcoholic steatohepatitis (NASH) is the common pathophysiological process resulting from chronic liver inflammation and oxidative stress. Although significant research has been carried out on the role of leptin-induced NADPH oxidase in fibrogenesis, the molecular mechanisms that connect the leptin-NADPH oxidase axis in upregulation of transforming growth factor (TGF)-β signaling have been unclear. We aimed to investigate the role of leptin-mediated upregulation of NADPH oxidase and its subsequent induction of micro-RNA 21 (miR21) in fibrogenesis. Human NASH livers and a high-fat (60% kcal) diet-fed chronic mouse model, where hepatotoxin bromodichloromethane was used to induce NASH, were used for this study. To prove the role of the leptin-NADPH oxidase-miR21 axis, mice deficient in genes for leptin, p47phox, and miR21 were used. Results showed that wild-type mice and human livers with NASH had increased oxidative stress, increased p47phox expression, augmented NF-κB activation, and increased miR21 levels. These mice and human livers showed increased TGF-β, SMAD2/3-SMAD4 colocalizations in the nucleus, increased immunoreactivity against Col1α, and α-SMA with a concomitant decrease in protein levels of SMAD7. Mice that were deficient in leptin or p47phox had decreased activated NF-κB and miR21 levels, suggesting the role of leptin and NADPH oxidase in inducing NF-κB-mediated miR21 expression. Further miR21 knockout mice had decreased colocalization events of SMAD2/3-SMAD4 in the nucleus, increased SMAD7 levels, and decreased fibrogenesis. Taken together, the studies show the novel role of leptin-NADPH oxidase induction of miR21 as a key regulator of TGF-β signaling and fibrogenesis in experimental and human NASH. Copyright © 2015 the American Physiological Society.

  12. NADPH Oxidase as a Therapeutic Target for Oxalate Induced Injury in Kidneys

    PubMed Central

    Peck, Ammon B.; Khan, Saeed R.

    2013-01-01

    A major role of the nicotinamide adenine dinucleotide phosphate (NADPH) oxidase family of enzymes is to catalyze the production of superoxides and other reactive oxygen species (ROS). These ROS, in turn, play a key role as messengers in cell signal transduction and cell cycling, but when they are produced in excess they can lead to oxidative stress (OS). Oxidative stress in the kidneys is now considered a major cause of renal injury and inflammation, giving rise to a variety of pathological disorders. In this review, we discuss the putative role of oxalate in producing oxidative stress via the production of reactive oxygen species by isoforms of NADPH oxidases expressed in different cellular locations of the kidneys. Most renal cells produce ROS, and recent data indicate a direct correlation between upregulated gene expressions of NADPH oxidase, ROS, and inflammation. Renal tissue expression of multiple NADPH oxidase isoforms most likely will impact the future use of different antioxidants and NADPH oxidase inhibitors to minimize OS and renal tissue injury in hyperoxaluria-induced kidney stone disease. PMID:23840917

  13. Identification of the NADPH Oxidase 4 Inhibiting Principle of Lycopus europaeus.

    PubMed

    Revoltella, Silvia; Baraldo, Giorgia; Waltenberger, Birgit; Schwaiger, Stefan; Kofler, Philipp; Moesslacher, Julia; Huber-Seidel, Astrid; Pagitz, Konrad; Kohl, Roland; Jansen-Duerr, Pidder; Stuppner, Hermann

    2018-03-14

    NADPH oxidase 4 (Nox4) has recently been implicated as driving force in cellular senescence. Thus, there is growing interest to develop Nox4 inhibitors, which might be valuable agents for cosmeceutical applications. Alpine plants represent a valuable source for the identification of novel bioactive natural products with anti-ageing effects, especially substances that protect plants against UV radiation, which is also known to contribute to the ageing of human skin. Therefore, the aim of this study was to identify novel Nox4 inhibitors from alpine plants. Within an initial screening of extracts of alpine plants on their ability to inhibit Nox4 activity in HEK cells, the methanolic extract of the subaerial parts of Lycopus europaeus showed a strong inhibition of Nox4 (81% chemiluminescence quenching) and a simultaneously high cell viability (91% vitality). Rosmarinic acid was isolated and identified as the major compound in this bioactive extract. It showed a dose dependent inhibitory activity on Nox4 with an IC 50 of 1 µM. Moreover, it also showed a significant inhibitory activity on Nox2 in the low micromolar range, whereas no inhibition of Nox5 was detected. Further investigations confirmed that the observed effects of rosmarinic acid on Nox2 and Nox4 are real inhibitory activities, and not due to ROS scavenging effects. Therefore, L. europaeus , which we demonstrated to be a good source of rosmarinic acid, has great potential for usage in cosmeceutical products with anti-ageing activity.

  14. The Importance of NADPH Oxidases and Redox Signaling in Angiogenesis

    PubMed Central

    Prieto-Bermejo, Rodrigo; Hernández-Hernández, Angel

    2017-01-01

    Eukaryotic cells have to cope with the constant generation of reactive oxygen species (ROS). Although the excessive production of ROS might be deleterious for cell biology, there is a plethora of evidence showing that moderate levels of ROS are important for the control of cell signaling and gene expression. The family of the nicotinamide adenine dinucleotide phosphate oxidases (NADPH oxidases or Nox) has evolved to produce ROS in response to different signals; therefore, they fulfil a central role in the control of redox signaling. The role of NADPH oxidases in vascular physiology has been a field of intense study over the last two decades. In this review we will briefly analyze how ROS can regulate signaling and gene expression. We will address the implication of NADPH oxidases and redox signaling in angiogenesis, and finally, the therapeutic possibilities derived from this knowledge will be discussed. PMID:28505091

  15. NADPH oxidases: new kids on the block.

    PubMed

    Geiszt, Miklós

    2006-07-15

    Reactive oxygen species (ROS) play a pivotal role in many physiological processes including host defense, hormone biosynthesis, fertilization and cellular signaling. Altered production of ROS has been implicated in the development of immunodeficiency, hypothyroidism and cardiovascular pathologies. In the last few years, several enzymes were identified at the molecular level, which are now thought to be responsible for ROS production observed in diverse tissues. These enzymes show a high degree of homology to the phagocytic NADPH oxidase and are now designated the Nox family of NADPH oxidases. This review updates our knowledge on six new members of the Nox family: Nox1, Nox3, Nox4, Nox5, Duox1 and Duox2.

  16. Monocyte and macrophage-targeted NADPH oxidase mediates antifungal host defense and regulation of acute inflammation in mice

    PubMed Central

    Grimm, Melissa J.; Vethanayagam, R. Robert; Almyroudis, Nikolaos G.; Dennis, Carly G.; Khan, A. Nazmul H.; D’Auria, Anthony; Singel, Kelly L.; Davidson, Bruce A.; Knight, Paul R.; Blackwell, Timothy S.; Hohl, Tobias M.; Mansour, Michael K.; Vyas, Jatin M.; Röhm, Marc; Urban, Constantin F.; Kelkka, Tiina; Holmdahl, Rikard; Segal, Brahm H.

    2013-01-01

    Chronic granulomatous disease, an inherited disorder of the NADPH oxidase in which phagocytes are defective in the generation of superoxide anion and downstream reactive oxidant species, is characterized by severe bacterial and fungal infections and excessive inflammation. Although NADPH oxidase isoforms exist in several lineages, reactive oxidant generation is greatest in neutrophils, where NADPH oxidase has been deemed vital for pathogen killing. In contrast, the function and importance of NADPH oxidase in macrophages are less clear. Therefore, we evaluated susceptibility to pulmonary aspergillosis in globally NADPH oxidase-deficient mice versus transgenic mice with monocyte/macrophage-targeted NADPH oxidase activity. We found that the lethal inoculum was more than 100-fold greater in transgenic versus globally NADPH oxidase-deficient mice. Consistent with these in vivo results, NADPH oxidase in mouse alveolar macrophages limited germination of phagocytosed Aspergillus fumigatus spores. Finally, globally NADPH oxidase-deficient mice developed exuberant neutrophilic lung inflammation and pro-inflammatory cytokine responses to zymosan, a fungal cell wall-derived product composed principally of particulate beta-glucans, whereas inflammation in transgenic and wildtype mice was mild and transient. Together, our studies identify a central role for monocyte/macrophage NADPH oxidase in controlling fungal infection and in limiting acute lung inflammation. PMID:23509361

  17. NADPH oxidase activation in neutrophils: Role of the Phosphorylation of its subunits.

    PubMed

    Belambri, Sahra A; Rolas, Loïc; Raad, Houssam; Hurtado-Nedelec, Margarita; Dang, Pham My-Chan; El-Benna, Jamel

    2018-05-14

    Neutrophils are key cells of innate immunity and during inflammation. Upon activation, they produce large amounts of superoxide anion (O 2 -. ) and ensuing reactive oxygen species (ROS) to kill phagocytized microbes. The enzyme responsible for O 2 -. production is called the phagocyte NADPH oxidase. This is a multicomponent enzyme system that becomes active after assembly of four cytosolic proteins (p47 phox , p67 phox , p40 phox and Rac2) with the transmembrane proteins (p22 phox and gp91 phox , which form the cytochrome b 558 ). gp91 phox represents the catalytic subunit of the NADPH oxidase and is also called NOX2. NADPH oxidase-derived ROS are essential for microbial killing and innate immunity; however, excessive ROS production induces tissue injury and prolonged inflammatory reactions that contribute to inflammatory diseases. Thus, NADPH oxidase activation must be tightly regulated in time and space in order to limit ROS production. NADPH oxidase activation is regulated by several processes such as phosphorylation of its components, exchange of GDP/GTP on Rac2 and binding of p47 phox and p40 phox to phospholipids. This review aims to provide new insights into the role of the phosphorylation of the NADPH oxidase components, i.e., gp91 phox , p22 phox , p47 phox , p67 phox and p40 phox , in the activation of this enzyme. This article is protected by copyright. All rights reserved. This article is protected by copyright. All rights reserved.

  18. Mitigation of NADPH Oxidase 2 Activity as a Strategy to Inhibit Peroxynitrite Formation*

    PubMed Central

    Zielonka, Jacek; Zielonka, Monika; VerPlank, Lynn; Cheng, Gang; Hardy, Micael; Ouari, Olivier; Ayhan, Mehmet Menaf; Podsiadły, Radosław; Sikora, Adam; Lambeth, J. David; Kalyanaraman, Balaraman

    2016-01-01

    Using high throughput screening-compatible assays for superoxide and hydrogen peroxide, we identified potential inhibitors of the NADPH oxidase (Nox2) isoform from a small library of bioactive compounds. By using multiple probes (hydroethidine, hydropropidine, Amplex Red, and coumarin boronate) with well defined redox chemistry that form highly diagnostic marker products upon reaction with superoxide (O2˙̄), hydrogen peroxide (H2O2), and peroxynitrite (ONOO−), the number of false positives was greatly decreased. Selected hits for Nox2 were further screened for their ability to inhibit ONOO− formation in activated macrophages. A new diagnostic marker product for ONOO− is reported. We conclude that the newly developed high throughput screening/reactive oxygen species assays could also be used to identify potential inhibitors of ONOO− formed from Nox2-derived O2˙̄ and nitric oxide synthase-derived nitric oxide. PMID:26839313

  19. NADPH oxidase inhibitor, diphenyleneiodonium prevents necroptosis in HK-2 cells.

    PubMed

    Dong, Wei; Li, Zhilian; Chen, Yuanhan; Zhang, Li; Ye, Zhiming; Liang, Huaban; Li, Ruizhao; Xu, Lixia; Zhang, Bin; Liu, Shuangxin; Wang, Weidong; Li, Chunling; Luo, Jialun; Shi, Wei; Liang, Xinling

    2017-09-01

    The aim of the present study was to investigate the protective effect of the NADPH oxidase inhibitor, diphenyleneiodonium (DPI) against necroptosis in renal tubular epithelial cells. A necroptosis model of HK-2 cells was established using tumor necrosis factor-α, benzyloxycarbonyl-Val-Ala-Asp-fluoromethylketone and antimycin A (collectively termed TZA), as in our previous research. The necroptosis inhibitor, necrostatin-1 (Nec-1) or the NADPH oxidase inhibitor, DPI were administered to the necroptosis model. Production of reactive oxygen species (ROS) was detected by dichlorodihydrofluorescein diacetate in the different groups, and the manner of cell death was identified by flow cytometry. Western blot analysis was used to determine the levels of phosphorylation of receptor-interacting protein kinase 3 (RIP-3) and mixed lineage kinase domain-like (MLKL), which are essential to necroptosis. The results revealed that TZA increased the percentages of propidium iodide-positive HK-2 cells from 1.22±0.69 to 8.98±0.73% (P<0.001), and augmented the phosphorylation of RIP-3 and MLKL. ROS levels were increased in the TZA group compared with the control group (27.74±1.60×10 4 vs. 18.51±1.10×10 4 , respectively; P<0.001), and could be inhibited by Nec-1 (TZA + Nec-1 group, 22.90±2.22×10 4 vs. TZA group, 27.74±1.60×10 4 ; P=0.01). DPI decreased ROS production (TZA + DPI group, 22.13±1.86×10 4 vs. TZA group, 27.74±1.60×10 4 ; P<0.001) and also reduced the proportions of necrosis in the necroptosis model (TZA + DPI group, 4.40±1.51% vs. TZA group, 8.98±0.73%; P<0.001). Phosphorylated RIP-3 and MLKL were also decreased by DPI treatment. The results indicate that ROS production increases in HK-2 cells undergoing necroptosis, and that the NADPH oxidase inhibitor, DPI may protect HK-2 cells from necroptosis via inhibition of ROS production.

  20. Reactive Oxygen Species and Inhibitors of Inflammatory Enzymes, NADPH Oxidase, and iNOS in Experimental Models of Parkinson's Disease

    PubMed Central

    Koppula, Sushruta; Kumar, Hemant; Kim, In Su; Choi, Dong-Kug

    2012-01-01

    Reactive oxygen species (ROSs) are emerging as important players in the etiology of neurodegenerative disorders including Parkinson's disease (PD). Out of several ROS-generating systems, the inflammatory enzymes nicotinamide adenine dinucleotide phosphate (NADPH) oxidase and inducible nitric oxide synthase (iNOS) were believed to play major roles. Mounting evidence suggests that activation of NADPH oxidase and the expression of iNOS are directly linked to the generation of highly reactive ROS which affects various cellular components and preferentially damage midbrain dopaminergic neurons in PD. Therefore, appropriate management or inhibition of ROS generated by these enzymes may represent a therapeutic target to reduce neuronal degeneration seen in PD. Here, we have summarized recently developed agents and patents claimed as inhibitors of NADPH oxidase and iNOS enzymes in experimental models of PD. PMID:22577256

  1. Globular adiponectin inhibits ethanol-induced reactive oxygen species production through modulation of NADPH oxidase in macrophages: involvement of liver kinase B1/AMP-activated protein kinase pathway.

    PubMed

    Kim, Mi Jin; Nagy, Laura E; Park, Pil-Hoon

    2014-09-01

    Adiponectin, an adipokine predominantly secreted from adipocytes, has been shown to play protective roles against chronic alcohol consumption. Although excessive reactive oxygen species (ROS) production in macrophages is considered one of the critical events for ethanol-induced damage in various target tissues, the effect of adiponectin on ethanol-induced ROS production is not clearly understood. In the present study, we investigated the effect of globular adiponectin (gAcrp) on ethanol-induced ROS production and the potential mechanisms underlying these effects of gAcrp in macrophages. Here we demonstrated that gAcrp prevented ethanol-induced ROS production in both RAW 264.7 macrophages and primary murine peritoneal macrophages. Globular adiponectin also inhibited ethanol-induced activation of NADPH oxidase. In addition, gAcrp suppressed ethanol-induced increase in the expression of NADPH oxidase subunits, including Nox2 and p22(phox), via modulation of nuclear factor-κB pathway. Furthermore, pretreatment with compound C, a selective inhibitor of AMPK, or knockdown of AMPK by small interfering RNA restored suppression of ethanol-induced ROS production and Nox2 expression by gAcrp. Finally, we found that gAcrp treatment induced phosphorylation of liver kinase B1 (LKB1), an upstream signaling molecule mediating AMPK activation. Knockdown of LKB1 restored gAcrp-suppressed Nox2 expression, suggesting that LKB1/AMPK pathway plays a critical role in the suppression of ethanol-induced ROS production and activation of NADPH oxidase by gAcrp. Taken together, these results demonstrate that globular adiponectin prevents ethanol-induced ROS production, at least in part, via modulation of NADPH oxidase in macrophages. Further, LKB1/AMPK axis plays an important role in the suppression of ethanol-induced NADPH oxidase activation by gAcrp in macrophages. Copyright © 2014 by The American Society for Pharmacology and Experimental Therapeutics.

  2. Glucose impairs aspirin inhibition in platelets through a NAD(P)H oxidase signaling pathway.

    PubMed

    Kobzar, Gennadi; Mardla, Vilja; Samel, Nigulas

    2017-07-01

    Hyperglycemia has been suggested to play a role in the increased platelet resistance to antiplatelet therapy in patients with diabetes mellitus. Exposure to high glucose impairs platelet inhibition by aspirin. It has been found that antioxidant agents reduce the effect of glucose, confirming the involvement of reactive oxygen species (ROS) in the effect of glucose. The aim of the study was to examine the mechanism of ROS increase by high glucose in aspirin-treated platelets. Platelet aggregation was measured by the optical method, and the production of ROS was detected using luminol-dependent horseradish peroxidase-enhanced chemiluminescence. We found that glucose did not affect ADP-induced platelet aggregation. However, it reduced the effect of aspirin on platelet aggregation, which was accompanied by an increase in ROS generation. The inhibition of NAD(P)H oxidase (NOX) prevented the glucose effect and ROS generation. The same result was recorded after the inhibition of p38 mitogen-activated protein kinases (p38 MAPK), phospholipase A 2 (PLA 2 ) or 12-lipoxygenase (12-LOX). The inhibition of TxA 2 receptor did not decrease the effect of glucose indicating that the effect was not caused by activation of TxA 2 receptors. Copyright © 2017 Elsevier Inc. All rights reserved.

  3. Dual blockade of aldosterone and angiotensin II additively suppresses TGF-beta and NADPH oxidase in the hypertensive kidney.

    PubMed

    Onozato, Maristela Lika; Tojo, Akihiro; Kobayashi, Naohiko; Goto, Atsuo; Matsuoka, Hiroaki; Fujita, Toshiro

    2007-05-01

    Angiotensin II blockade and spironolactone effectively reduces proteinuria in humans. To clarify the mechanisms of the beneficial effect of blockade of both aldosterone and angiotensin II, we associated the aldosterone antagonist eplerenone to an angiotensin-converting enzyme inhibitor (ACEI) and examined the effect on renal transforming growth factor (TGF)-beta expression and oxidative stress by nicotinamide adenine dinucleotide phosphate (NADPH) oxidase in the Dahl salt-sensitive rat with heart failure (DSHF). Dahl salt-resistant control rats and DSHF rats were fed with 8% NaCl diet and at 11 weeks the DSHF rats were treated with vehicle, eplerenone (Epl), trandolapril or a combination of both drugs for 7 weeks. DSHF rats showed increased NADPH oxidase and decreased superoxide dismutase (SOD) resulting in increased oxidative stress. ACEI and Epl reduced NADPH oxidase showing an additive effect in their combination; ACEI increased manganese SOD (MnSOD) and Epl increased MnSOD, copper-zinc SOD and catalase, resulting in the lowest levels of oxidative stress with the combination therapy. Glomerulosclerosis and proteinuria were increased in the DSHF rats, and Epl suppressed them more effectively than ACEI to levels not different from the combination of both, showing a positive correlation with NADPH oxidase expression and TGF-beta. Renal TGF-beta was specifically suppressed with Epl The association of Epl to ACEI is beneficial due to further reduction of NADPH oxidase and specific inhibition of TGF-beta resulting in improvement of renal damage.

  4. NADPH Oxidase-Dependent Signaling in Endothelial Cells: Role in Physiology and Pathophysiology

    PubMed Central

    Ushio-Fukai, Masuko; Malik, Asrar B.

    2009-01-01

    Abstract Reactive oxygen species (ROS) including superoxide (O2·−) and hydrogen peroxide (H2O2) are produced endogenously in response to cytokines, growth factors; G-protein coupled receptors, and shear stress in endothelial cells (ECs). ROS function as signaling molecules to mediate various biological responses such as gene expression, cell proliferation, migration, angiogenesis, apoptosis, and senescence in ECs. Signal transduction activated by ROS, “oxidant signaling,” has received intense investigation. Excess amount of ROS contribute to various pathophysiologies, including endothelial dysfunction, atherosclerosis, hypertension, diabetes, and acute respiratory distress syndrome (ARDS). The major source of ROS in EC is a NADPH oxidase. The prototype phagaocytic NADPH oxidase is composed of membrane-bound gp91phox and p22hox, as well as cytosolic subunits such as p47phox, p67phox and small GTPase Rac. In ECs, in addition to all the components of phagocytic NADPH oxidases, homologues of gp91phox (Nox2) including Nox1, Nox4, and Nox5 are expressed. The aim of this review is to provide an overview of the emerging area of ROS derived from NADPH oxidase and oxidant signaling in ECs linked to physiological and pathophysiological functions. Understanding these mechanisms may provide insight into the NADPH oxidase and oxidant signaling components as potential therapeutic targets. Antioxid. Redox Signal. 11, 791–810. PMID:18783313

  5. Functional Assembly of Soluble and Membrane Recombinant Proteins of Mammalian NADPH Oxidase Complex.

    PubMed

    Souabni, Hajer; Ezzine, Aymen; Bizouarn, Tania; Baciou, Laura

    2017-01-01

    Activation of phagocyte cells from an innate immune system is associated with a massive consumption of molecular oxygen to generate highly reactive oxygen species (ROS) as microbial weapons. This is achieved by a multiprotein complex, the so-called NADPH oxidase. The activity of phagocyte NADPH oxidase relies on an assembly of more than five proteins, among them the membrane heterodimer named flavocytochrome b 558 (Cytb 558 ), constituted by the tight association of the gp91 phox (also named Nox2) and p22 phox proteins. The Cytb 558 is the membrane catalytic core of the NADPH oxidase complex, through which the reducing equivalent provided by NADPH is transferred via the associated prosthetic groups (one flavin and two hemes) to reduce dioxygen into superoxide anion. The other major proteins (p47 phox , p67 phox , p40 phox , Rac) requisite for the complex activity are cytosolic proteins. Thus, the NADPH oxidase functioning relies on a synergic multi-partner assembly that in vivo can be hardly studied at the molecular level due to the cell complexity. Thus, a cell-free assay method has been developed to study the NADPH oxidase activity that allows measuring and eventually quantifying the ROS generation based on optical techniques following reduction of cytochrome c. This setup is a valuable tool for the identification of protein interactions, of crucial components and additives for a functional enzyme. Recently, this method was improved by the engineering and the production of a complete recombinant NADPH oxidase complex using the combination of purified proteins expressed in bacterial and yeast host cells. The reconstitution into artificial membrane leads to a fully controllable system that permits fine functional studies.

  6. NADPH oxidases as novel pharmacologic targets against influenza A virus infection.

    PubMed

    Vlahos, Ross; Selemidis, Stavros

    2014-12-01

    Influenza A viruses represent a major global health care challenge, with imminent pandemics, emerging antiviral resistance, and long lag times for vaccine development, raising a pressing need for novel pharmacologic strategies that ideally target the pathology irrespective of the infecting strain. Reactive oxygen species (ROS) pervade all facets of cell biology with both detrimental and protective properties. Indeed, there is compelling evidence that activation of the NADPH oxidase 2 (NOX2) isoform of the NADPH oxidase family of ROS-producing enzymes promotes lung oxidative stress, inflammation, injury, and dysfunction resulting from influenza A viruses of low to high pathogenicity, as well as impeding virus clearance. By contrast, the dual oxidase isoforms produce ROS that provide vital protective antiviral effects for the host. In this review, we propose that inhibitors of NOX2 are better alternatives than broad-spectrum antioxidant approaches for treatment of influenza pathologies, for which clinical efficacy may have been limited owing to poor bioavailability and inadvertent removal of beneficial ROS. Finally, we briefly describe the current suite of NADPH oxidase inhibitors and the molecular features of the NADPH oxidase enzymes that could be exploited by drug discovery for development of more specific and novel inhibitors to prevent or treat disease caused by influenza. Copyright © 2014 by The American Society for Pharmacology and Experimental Therapeutics.

  7. Method to Detect the Cellular Source of Over-Activated NADPH Oxidases Using NAD(P)H Fluorescence Lifetime Imaging.

    PubMed

    Bremer, Daniel; Leben, Ruth; Mothes, Ronja; Radbruch, Helena; Niesner, Raluca

    2017-04-03

    Fluorescence-lifetime imaging microscopy (FLIM) is a technique to generate images, in which the contrast is obtained by the excited-state lifetime of fluorescent molecules instead of their intensity and emission spectrum. The ubiquitous coenzymes NADH and NADPH, hereafter NAD(P)H, in cells show a short fluorescence lifetime ≈400 psec in the free-state and a longer fluorescence lifetime when bound to enzymes. The fluorescence lifetime of NAD(P)H in this state depends on the binding-site on the specific enzyme. In the case of NADPH bound to members of the NADPH oxidases family we measured a fluorescence lifetime of 3650 psec as compared to enzymes typically active in cells, in which case fluorescence lifetimes of ∼2000 psec are measured. Here we present a robust protocol based on NAD(P)H fluorescence lifetime imaging in isolated cells to distinguish between normally active enzymes and NADPH oxidases, mainly responsible for oxidative stress. © 2017 by John Wiley & Sons, Inc. Copyright © 2017 John Wiley & Sons, Inc.

  8. NADPH Oxidase versus Mitochondria-Derived ROS in Glucose-Induced Apoptosis of Pericytes in Early Diabetic Retinopathy

    PubMed Central

    Mustapha, Nik M.; Tarr, Joanna M.; Kohner, Eva M.; Chibber, Rakesh

    2010-01-01

    Objectives. Using apocynin (inhibitor of NADPH oxidase), and Mitoquinol 10 nitrate (MitoQ; mitochondrial-targeted antioxidant), we addressed the importance of mitochondria versus NADPH oxidase-derived ROS in glucose-induced apoptosis of pericytes. Methods. NADPH oxidase was localised using Western blot analysis and cytochrome C reduction assay. Apoptosis was detected by measuring caspase-3 activity. Intracellular glucose concentration, ROS formation and Nε-(carboxymethyl) lysine (CML) content were measured using Amplex Red assay kit, dihydroethidium (DHE), and competitive immunoabsorbant enzyme-linked assay (ELISA), respectively. Results. NADPH oxidase was localised in the cytoplasm of pericytes suggesting ROS production within intracellular compartments. High glucose (25 mM) significantly increased apoptosis, intracellular glucose concentration, and CML content. Apoptosis was associated with increased gp91phox expression, activity of NADPH oxidase, and intracellular ROS production. Apocynin and not MitoQ significantly blunted the generation of ROS, formation of intracellular CML and apoptosis. Conclusions. NADPH oxidase and not mitochondria-derived ROS is responsible for the accelerated apoptosis of pericytes in diabetic retinopathy. PMID:20652059

  9. Effects of co-administration of dietary sodium arsenite and an NADPH oxidase inhibitor on the rat bladder epithelium.

    PubMed

    Suzuki, Shugo; Arnold, Lora L; Pennington, Karen L; Kakiuchi-Kiyota, Satoko; Cohen, Samuel M

    2009-06-30

    Arsenite (As(III)), an inorganic arsenical, is a known human carcinogen, inducing tumors of the skin, urinary bladder and lung. It is metabolized to organic methylated arsenicals. Oxidative stress has been suggested as a mechanism for arsenic-induced carcinogenesis. Reactive oxygen species (ROS) can be important factors for carcinogenesis and tumor progression. Nicotinamide adenine dinucleotide phosphate (NADPH) oxidase is known to produce intracellular ROS, therefore, we investigated the ability of apocynin (acetovanillone), an NADPH oxidase inhibitor, to inhibit the cytotoxicity and regenerative cell proliferation of arsenic in vitro and in vivo. Apocynin had similar effects in reducing the cytotoxicity of As(III) and dimethylarsinous acid (DMA(III)) in rat urothelial cells in vitro. When tested at the same concentrations as apocynin, other antioxidants, such as l-ascorbate and N-acetylcysteine, did not inhibit As(III)-induced cytotoxicity but they were more effective at inhibiting DMA(III)-induced cytotoxicity compared with apocynin. In vivo, female rats were treated for 3 weeks with 100ppm As(III). Immunohistochemical staining for 8-hydroxy-2'-deoxyguanosine (8-OHdG) showed that apocynin reduced oxidative stress partially induced by As(III) treatment on rat urothelium, and significantly reduced the cytotoxicity of superficial cells detected by scanning electron microscopy (SEM). However, based on the incidence of simple hyperplasia and the bromodeoxyuridine (BrdU) labeling index, apocynin did not inhibit As(III)-induced urothelial cell proliferation. These data suggest that the NADPH oxidase inhibitor, apocynin, may have the ability to partially inhibit arsenic-induced oxidative stress and cytotoxicity of the rat bladder epithelium in vitro and in vivo. However, apocynin did not inhibit the regenerative cell proliferation induced by arsenite in a short-term study.

  10. RhoA/ROCK downregulates FPR2-mediated NADPH oxidase activation in mouse bone marrow granulocytes.

    PubMed

    Filina, Julia V; Gabdoulkhakova, Aida G; Safronova, Valentina G

    2014-10-01

    Polymorphonuclear neutrophils (PMNs) express the high and low affinity receptors to formylated peptides (mFPR1 and mFPR2 in mice, accordingly). RhoA/ROCK (Rho activated kinase) pathway is crucial for cell motility and oxidase activity regulated via FPRs. There are contradictory data on RhoA-mediated regulation of NADPH oxidase activity in phagocytes. We have shown divergent Rho GTPases signaling via mFPR1 and mFPR2 to NADPH oxidase in PMNs from inflammatory site. The present study was aimed to find out the role of RhoA/ROCK in the respiratory burst activated via mFPR1 and mFPR2 in the bone marrow PMNs. Different kinetics of RhoA activation were detected with 0.1μM fMLF and 1μM WKYMVM operating via mFPR1 and mFPR2, accordingly. RhoA was translocated in fMLF-activated cells towards the cell center and juxtamembrane space versus uniform allocation in the resting cells. Specific inhibition of RhoA by CT04, Rho inhibitor I, weakly depressed the respiratory burst induced via mFPR1, but significantly increased the one induced via mFPR2. Inhibition of ROCK, the main effector of RhoA, by Y27632 led to the same effect on the respiratory burst. Regulation of mFPR2-induced respiratory response by ROCK was impossible under the cytoskeleton disruption by cytochalasin D, whereas it persisted in the case of mFPR1 activation. Thus we suggest RhoA to be one of the regulatory and signal transduction components in the respiratory burst through FPRs in the mouse bone marrow PMNs. Both mFPR1 and mFPR2 binding with a ligand trigger the activation of RhoA. FPR1 signaling through RhoA/ROCK increases NADPH-oxidase activity. But in FPR2 action RhoA/ROCK together with cytoskeleton-linked systems down-regulates NADPH-oxidase. This mechanism could restrain the reactive oxygen species dependent damage of own tissues during the chemotaxis of PMNs and in the resting cells. Copyright © 2014 Elsevier Inc. All rights reserved.

  11. NADPH oxidases in the arbuscular mycorrhizal symbiosis.

    PubMed

    Belmondo, Simone; Calcagno, Cristina; Genre, Andrea; Puppo, Alain; Pauly, Nicolas; Lanfranco, Luisa

    2016-01-01

    Plant NADPH oxidases are the major source of reactive oxygen species (ROS) that plays key roles as both signal and stressor in several plant processes, including defense responses against pathogens. ROS accumulation in root cells during arbuscular mycorrhiza (AM) development has raised the interest in understanding how ROS-mediated defense programs are modulated during the establishment of this mutualistic interaction. We have recently analyzed the expression pattern of 5 NADPH oxidase (also called RBOH) encoding genes in Medicago truncatula, showing that only one of them (MtRbohE) is specifically upregulated in arbuscule-containing cells. In line with this result, RNAi silencing of MtRbohE generated a strong alteration in root colonization, with a significant reduction in the number of arbusculated cells. On this basis, we propose that MtRBOHE-mediated ROS production plays a crucial role in the intracellular accommodation of arbuscules.

  12. NADPH oxidases in the arbuscular mycorrhizal symbiosis

    PubMed Central

    Belmondo, Simone; Calcagno, Cristina; Genre, Andrea; Puppo, Alain; Pauly, Nicolas; Lanfranco, Luisa

    2016-01-01

    ABSTRACT Plant NADPH oxidases are the major source of reactive oxygen species (ROS) that plays key roles as both signal and stressor in several plant processes, including defense responses against pathogens. ROS accumulation in root cells during arbuscular mycorrhiza (AM) development has raised the interest in understanding how ROS-mediated defense programs are modulated during the establishment of this mutualistic interaction. We have recently analyzed the expression pattern of 5 NADPH oxidase (also called RBOH) encoding genes in Medicago truncatula, showing that only one of them (MtRbohE) is specifically upregulated in arbuscule-containing cells. In line with this result, RNAi silencing of MtRbohE generated a strong alteration in root colonization, with a significant reduction in the number of arbusculated cells. On this basis, we propose that MtRBOHE-mediated ROS production plays a crucial role in the intracellular accommodation of arbuscules. PMID:27018627

  13. Cell-free NADPH oxidase activation assays: "in vitro veritas".

    PubMed

    Pick, Edgar

    2014-01-01

    The superoxide (O2 (∙-))-generating NADPH oxidase complex of phagocytes comprises a membrane-imbedded heterodimeric flavocytochrome, known as cytochrome b 558 (consisting of Nox2 and p22 (phox) ) and four cytosolic regulatory proteins, p47 (phox) , p67 (phox) , p40 (phox) , and the small GTPase Rac. Under physiological conditions, in the resting phagocyte, O2 (∙-) generation is initiated by engagement of membrane receptors by a variety of stimuli, followed by specific signal transduction sequences leading to the translocation of the cytosolic components to the membrane and their association with the cytochrome. A consequent conformational change in Nox2 initiates the electron "flow" along a redox gradient, from NADPH to oxygen, leading to the one-electron reduction of molecular oxygen to O2 (∙-). Methodological difficulties in the dissection of this complex mechanism led to the design "cell-free" systems (also known as "broken cells" or in vitro systems). In these, membrane receptor stimulation and all or part of the signal transduction sequence are missing, the accent being placed on the actual process of "NADPH oxidase assembly," thus on the formation of the complex between cytochrome b 558 and the cytosolic components and the resulting O2 (∙-) generation. Cell-free assays consist of a mixture of the individual components of the NADPH oxidase complex, derived from resting phagocytes or in the form of purified recombinant proteins, exposed in vitro to an activating agent (distinct from and unrelated to whole cell stimulants), in the presence of NADPH and oxygen. Activation is commonly quantified by measuring the primary product of the reaction, O2 (∙-), trapped immediately after its generation by an appropriate acceptor in a kinetic assay, permitting the calculation of the linear rate of O2 (∙-) production, but numerous variations exist, based on the assessment of reaction products or the consumption of substrates. Cell-free assays played a paramount

  14. A benzoxazine derivative induces vascular endothelial cell apoptosis in the presence of fibroblast growth factor-2 by elevating NADPH oxidase activity and reactive oxygen species levels.

    PubMed

    Zhao, Jing; He, Qiuxia; Cheng, Yizhe; Zhao, Baoxiang; Zhang, Yun; Zhang, Shangli; Miao, Junying

    2009-09-01

    Previously, we found that 6,8-dichloro-2,3-dihydro-3-hydroxymethyl-1,4-benzoxazine (DBO) promoted apoptosis of human umbilical vascular endothelial cells (HUVECs) deprived of growth factors. In this study, we aimed to investigate the effect of DBO and its mechanism of action on angiogenesis and apoptosis of HUVECs in the presence of fibroblast growth factor-2 (FGF-2), which promotes angiogenesis and inhibits apoptosis in vivo and in vitro. DBO significantly inhibited capillary-like tube formation by promoting apoptosis of HUVECs in the presence of FGF-2 in vitro. Furthermore, DBO elevated the levels of reactive oxygen species (ROS) and nitric oxide (NO) and increased the activity of NADPH oxidase and inducible nitric oxide synthase (iNOS) in promoting apoptosis under this condition. Moreover, when NADPH oxidase was inhibited by its specific inhibitor, dibenziodolium chloride (DPI), DBO could not elevate ROS and NO levels in HUVECs. The data suggest that DBO is a new modulator of apoptosis in vitro, and it might function by increasing the activity of NADPH oxidase and iNOS, subsequently elevating the levels of ROS and NO in HUVECs. The findings of this study provide a new small molecule for investigating the FGF-2/NADPH oxidase/iNOS signaling pathway in apoptosis.

  15. NADPH Oxidase-Driven Phagocyte Recruitment Controls Candida albicans Filamentous Growth and Prevents Mortality

    PubMed Central

    Brothers, Kimberly M.; Gratacap, Remi L.; Barker, Sarah E.; Newman, Zachary R.; Norum, Ashley; Wheeler, Robert T.

    2013-01-01

    Candida albicans is a human commensal and clinically important fungal pathogen that grows as both yeast and hyphal forms during human, mouse and zebrafish infection. Reactive oxygen species (ROS) produced by NADPH oxidases play diverse roles in immunity, including their long-appreciated function as microbicidal oxidants. Here we demonstrate a non-traditional mechanistic role of NADPH oxidase in promoting phagocyte chemotaxis and intracellular containment of fungi to limit filamentous growth. We exploit the transparent zebrafish model to show that failed NADPH oxidase-dependent phagocyte recruitment to C. albicans in the first four hours post-infection permits fungi to germinate extracellularly and kill the host. We combine chemical and genetic tools with high-resolution time-lapse microscopy to implicate both phagocyte oxidase and dual-specific oxidase in recruitment, suggesting that both myeloid and non-myeloid cells promote chemotaxis. We show that early non-invasive imaging provides a robust tool for prognosis, strongly connecting effective early immune response with survival. Finally, we demonstrate a new role of a key regulator of the yeast-to-hyphal switching program in phagocyte-mediated containment, suggesting that there are species-specific methods for modulation of NADPH oxidase-independent immune responses. These novel links between ROS-driven chemotaxis and fungal dimorphism expand our view of a key host defense mechanism and have important implications for pathogenesis. PMID:24098114

  16. RXR agonists inhibit high glucose-induced upregulation of inflammation by suppressing activation of the NADPH oxidase-nuclear factor-κB pathway in human endothelial cells.

    PubMed

    Ning, R B; Zhu, J; Chai, D J; Xu, C S; Xie, H; Lin, X Y; Zeng, J Z; Lin, J X

    2013-12-13

    An inflammatory response induced by high glucose is a cause of endothelial dysfunction in diabetes and is an important contributing link to atherosclerosis. Diabetes is an independent risk factor of atherosclerosis and activation of retinoid X receptor (RXR) has been shown to exert anti-atherogenic effects. In the present study, we examined the effects of the RXR ligands 9-cis-retinoic acid (9-cis-RA) and SR11237 on high glucose-induced inflammation in human umbilical endothelial vein endothelial cells (HUVECs) and explored the potential mechanism. Our results showed that the inflammation induced by high-glucose in HUVECs was mainly mediated by the activation of nuclear factor-B (NF- κB). High glucose-induced expression of intercellular adhesion molecule-1 (ICAM-1) and vascular cell adhesion molecule-1 (VCAM-1) were in comparison, significantly decreased by treatment with RXR. The effect of RXR agonists was mainly due to the inhibition of NF-κB activation. Using pharmacological inhibitors and siRNA, we confirmed that nicotinamide adenine dinucleotide phosphate (NADPH) oxidase was an upstream activator of NF-κB. Furthermore, RXR agonists significantly inhibited high glucose-induced activation of NADPH oxidase and significantly decreased the production of reactive oxygen species (ROS). To explore whether the rapid inhibitory effects of RXR agonists were in fact mediated by RXR, we examined the effect of RXR downregulation by RXR siRNA. Our results showed that RXR siRNA largely abrogated the effects of RXR agonists, suggesting the requirement of RXR expression. Therefore, we have shown that RXR is involved in the regulation of NADPH oxidase- NF-κB signal pathway, as the RXR ligands antagonized the inflammatory response in HUVECs induced by high glucose.

  17. Regulation of superoxide anion production by NADPH oxidase in monocytes/macrophages: contributions to atherosclerosis.

    PubMed

    Cathcart, Martha K

    2004-01-01

    Monocyte extravasation into the vessel wall has been shown to be a critical step in the development of atherosclerosis. Upon activation, monocytes produce a burst of superoxide anion due to activation of the NADPH oxidase enzyme complex. Monocyte-derived superoxide anion contributes to oxidant stress in inflammatory sites, is required for monocyte-mediated LDL oxidation, and alters basic cell functions such as adhesion and proliferation. We hypothesize that monocyte-derived superoxide anion production contributes to atherosclerotic lesion formation. In this brief review, we summarize our current understanding of the signal transduction pathways regulating NADPH oxidase activation and related superoxide anion production in activated human monocytes. Novel pathways are identified that may serve as future targets for therapeutic intervention in this pathogenic process. The contributions of superoxide anion and NADPH oxidase to atherogenesis are discussed. Future experiments are needed to clarify the exact role of NADPH oxidase-derived superoxide anion in atherogenesis, particularly that derived from monocytes.

  18. Interrupted reperfusion reduces the activation of NADPH oxidase after cerebral I/R injury.

    PubMed

    Shen, Jia; Bai, Xiao-Yin; Qin, Yuan; Jin, Wei-Wei; Zhou, Jing-Yin; Zhou, Ji-Ping; Yan, Ying-Gang; Wang, Qiong; Bruce, Iain C; Chen, Jiang-Hua; Xia, Qiang

    2011-06-15

    Interrupted reperfusion reduces ischemia/reperfusion (I/R) injury. This study was designed to determine whether NADPH oxidase participates in the neural protection against global I/R injury after interrupted reperfusion. Mice were randomly divided into five groups: sham (sham-operated), I/R (20-min global I/R), RR (I/R+interrupted reperfusion), Apo (I/R+apocynin administration), and RR+Apo. Behavioral tests (pole test, beam walking, and Morris water maze) and Nissl staining were undertaken in all five groups; superoxide levels, expression of gp91(phox) and p47(phox), p47(phox) translocation, and Rac1 activation were measured in the sham, I/R, and RR groups. The motor coordination, bradykinesia, and spatial learning and memory, as well as the neuron survival rates, were better in the RR, Apo, and RR+Apo groups than in the I/R group. The NADPH oxidase-dependent superoxide levels, p47(phox) and gp91(phox) expression, p47(phox) translocation, and Rac1 activation were lower in the RR group than in the I/R group. In conclusion, the neural protective effect of interrupted reperfusion is at least partly mediated by decreasing the expression and assembly of NADPH oxidase and the levels of NADPH oxidase-derived superoxide. The most striking reduction Rac1-GTP in the RR group suggests that interrupted reperfusion also acts on the activation of assembled NADPH oxidase by reducing the availability of Rac1-GTP. Copyright © 2011 Elsevier Inc. All rights reserved.

  19. Ebselen and congeners inhibit NADPH oxidase 2-dependent superoxide generation by interrupting the binding of regulatory subunits.

    PubMed

    Smith, Susan M E; Min, Jaeki; Ganesh, Thota; Diebold, Becky; Kawahara, Tsukasa; Zhu, Yerun; McCoy, James; Sun, Aiming; Snyder, James P; Fu, Haian; Du, Yuhong; Lewis, Iestyn; Lambeth, J David

    2012-06-22

    NADPH oxidases (Nox) are a primary source of reactive oxygen species (ROS), which function in normal physiology and, when overproduced, in pathophysiology. Recent studies using mice deficient in Nox2 identify this isoform as a novel target against Nox2-implicated inflammatory diseases. Nox2 activation depends on the binding of the proline-rich domain of its heterodimeric partner p22phox to p47phox. A high-throughput screen that monitored this interaction via fluorescence polarization identified ebselen and several of its analogs as inhibitors. Medicinal chemistry was performed to explore structure-activity relationships and to optimize potency. Ebselen and analogs potently inhibited Nox1 and Nox2 activity but were less effective against other isoforms. Ebselen also blocked translocation of p47phox to neutrophil membranes. Thus, ebselen and its analogs represent a class of compounds that inhibit ROS generation by interrupting the assembly of Nox2-activating regulatory subunits. Copyright © 2012 Elsevier Ltd. All rights reserved.

  20. Role of NADPH Oxidase-4 in Human Endothelial Progenitor Cells

    PubMed Central

    Hakami, Nora Y.; Ranjan, Amaresh K.; Hardikar, Anandwardhan A.; Dusting, Greg J.; Peshavariya, Hitesh M.

    2017-01-01

    Introduction: Endothelial progenitor cells (EPCs) display a unique ability to promote angiogenesis and restore endothelial function in injured blood vessels. NADPH oxidase 4 (NOX4)-derived hydrogen peroxide (H2O2) serves as a signaling molecule and promotes endothelial cell proliferation and migration as well as protecting against cell death. However, the role of NOX4 in EPC function is not completely understood. Methods: EPCs were isolated from human saphenous vein and mammary artery discarded during bypass surgery. NOX4 gene and protein expression in EPCs were measured by real time-PCR and Western blot analysis respectively. NOX4 gene expression was inhibited using an adenoviral vector expressing human NOX4 shRNA (Ad-NOX4i). H2O2 production was measured by Amplex red assay. EPC migration was evaluated using a transwell migration assay. EPC proliferation and viability were measured using trypan blue counts. Results: Inhibition of NOX4 using Ad-NOX4i reduced Nox4 gene and protein expression as well as H2O2 formation in EPCs. Inhibition of NOX4-derived H2O2 decreased both proliferation and migration of EPCs. Interestingly, pro-inflammatory cytokine tumor necrosis factor alpha (TNFα) decreased NOX4 expression and reduced survival of EPCs. However, the survival of EPCs was further diminished by TNF-α in NOX4-knockdown cells, suggesting that NOX4 has a protective role in EPCs. Conclusion: These findings suggest that NOX4-type NADPH oxidase is important for proliferation and migration functions of EPCs and protects against pro-inflammatory cytokine induced EPC death. These properties of NOX4 may facilitate the efficient function of EPCs which is vital for successful neovascularization. PMID:28386230

  1. Extra virgin olive oil rich in polyphenols modulates VEGF-induced angiogenic responses by preventing NADPH oxidase activity and expression.

    PubMed

    Calabriso, Nadia; Massaro, Marika; Scoditti, Egeria; D'Amore, Simona; Gnoni, Antonio; Pellegrino, Mariangela; Storelli, Carlo; De Caterina, Raffaele; Palasciano, Giuseppe; Carluccio, Maria Annunziata

    2016-02-01

    Previous studies have shown the antiinflammatory, antioxidant and antiangiogenic properties by pure olive oil polyphenols; however, the effects of olive oil phenolic fraction on the inflammatory angiogenesis are unknown. In this study, we investigated the effects of the phenolic fraction (olive oil polyphenolic extract, OOPE) from extra virgin olive oil and related circulating metabolites on the VEGF-induced angiogenic responses and NADPH oxidase activity and expression in human cultured endothelial cells. We found that OOPE (1-10 μg/ml), at concentrations achievable nutritionally, significantly reduced, in a concentration-dependent manner, the VEGF-induced cell migration, invasiveness and tube-like structure formation through the inhibition of MMP-2 and MMP-9. OOPE significantly (P<0.05) reduced VEGF-induced intracellular reactive oxygen species by modulating NADPH oxidase activity, p47phox membrane translocation and the expression of Nox2 and Nox4. Moreover, the treatment of endothelial cells with serum obtained 4 h after acute intake of extra virgin olive oil, with high polyphenol content, decreased VEGF-induced NADPH oxidase activity and Nox4 expression, as well as, MMP-9 expression, as compared with fasting control serum. Overall, native polyphenols and serum metabolites of extra virgin olive oil rich in polyphenols are able to lower the VEGF-induced angiogenic responses by preventing endothelial NADPH oxidase activity and decreasing the expression of selective NADPH oxidase subunits. Our results provide an alternative mechanism by which the consumption of olive oil rich in polyphenols may account for a reduction of oxidative stress inflammatory-related sequelae associated with chronic degenerative diseases. Copyright © 2015 Elsevier Inc. All rights reserved.

  2. The Intimate and Controversial Relationship between Voltage Gated Proton Channels and the Phagocyte NADPH Oxidase

    PubMed Central

    DeCoursey, Thomas E.

    2016-01-01

    Summary One of the most fascinating and exciting periods in my scientific career entailed dissecting the symbiotic relationship between two membrane transporters, the NADPH oxidase complex and voltage gated proton channels (HV1). By the time I entered this field, there had already been substantial progress toward understanding NADPH oxidase, but HV1 were known only to a tiny handful of cognoscenti around the world. Having identified the first proton currents in mammalian cells in 1991, I needed to find a clear function for these molecules if the work was to become fundable. The then-recent discoveries of Henderson, Chappell, and colleagues in 1987–1988 that led them to hypothesize interactions of both molecules during the respiratory burst of phagocytes provided an excellent opportunity. In a nutshell, both transporters function by moving electrical charge across the membrane: NADPH oxidase moves electrons and HV1 moves protons. The consequences of electrogenic NADPH oxidase activity on both membrane potential and pH strongly self-limit this enzyme. Fortunately, both consequences specifically activate HV1, and HV1 activity counteracts both consequences, a kind of yin-yang relationship. Notwithstanding a decade starting in 1995 when many believed the opposite, these are two separate molecules that function independently despite their being functionally interdependent in phagocytes. The relationship between NADPH oxidase and HV1 has become a paradigm that somewhat surprisingly has now extended well beyond the phagocyte NADPH oxidase -- an industrial strength producer of reactive oxygen species (ROS) -- to myriad other cells that produce orders of magnitude less ROS for signaling purposes. These cells with their seven NADPH oxidase (NOX) isoforms provide a vast realm of mechanistic obscurity that will occupy future studies for years to come. PMID:27558336

  3. The intimate and controversial relationship between voltage-gated proton channels and the phagocyte NADPH oxidase.

    PubMed

    DeCoursey, Thomas E

    2016-09-01

    One of the most fascinating and exciting periods in my scientific career entailed dissecting the symbiotic relationship between two membrane transporters, the Nicotinamide adenine dinucleotide phosphate reduced form (NADPH) oxidase complex and voltage-gated proton channels (HV 1). By the time I entered this field, there had already been substantial progress toward understanding NADPH oxidase, but HV 1 were known only to a tiny handful of cognoscenti around the world. Having identified the first proton currents in mammalian cells in 1991, I needed to find a clear function for these molecules if the work was to become fundable. The then-recent discoveries of Henderson, Chappell, and colleagues in 1987-1988 that led them to hypothesize interactions of both molecules during the respiratory burst of phagocytes provided an excellent opportunity. In a nutshell, both transporters function by moving electrical charge across the membrane: NADPH oxidase moves electrons and HV 1 moves protons. The consequences of electrogenic NADPH oxidase activity on both membrane potential and pH strongly self-limit this enzyme. Fortunately, both consequences specifically activate HV 1, and HV 1 activity counteracts both consequences, a kind of yin-yang relationship. Notwithstanding a decade starting in 1995 when many believed the opposite, these are two separate molecules that function independently despite their being functionally interdependent in phagocytes. The relationship between NADPH oxidase and HV 1 has become a paradigm that somewhat surprisingly has now extended well beyond the phagocyte NADPH oxidase - an industrial strength producer of reactive oxygen species (ROS) - to myriad other cells that produce orders of magnitude less ROS for signaling purposes. These cells with their seven NADPH oxidase (NOX) isoforms provide a vast realm of mechanistic obscurity that will occupy future studies for years to come. © 2016 John Wiley & Sons A/S. Published by John Wiley & Sons Ltd.

  4. The NADPH oxidase inhibitor diphenyleneiodonium is also a potent inhibitor of cholinesterases and the internal Ca2+ pump

    PubMed Central

    Tazzeo, T; Worek, F; Janssen, LJ

    2009-01-01

    Background and purpose: Diphenyleneiodonium (DPI) is often used as an NADPH oxidase inhibitor, but is increasingly being found to have unrelated side effects. We investigated its effects on smooth muscle contractions and the related mechanisms. Experimental approach: We studied isometric contractions in smooth muscle strips from bovine trachea. Cholinesterase activity was measured using a spectrophotometric assay; internal Ca2+ pump activity was assessed by Ca2+ uptake into smooth muscle microsomes. Key results: Contractions to acetylcholine were markedly enhanced by DPI (10−4 M), whereas those to carbachol (CCh) were not, suggesting a possible inhibition of cholinesterase. DPI markedly suppressed contractions evoked by CCh, KCl and 5-HT, and also unmasked phasic activity in otherwise sustained responses. Direct biochemical assays confirmed that DPI was a potent inhibitor of acetylcholinesterase and butyrylcholinesterase (IC50∼8 × 10−6 M and 6 × 10−7 M, respectively), following a readily reversible, mixed non-competitive type of inhibition. The inhibitory effects of DPI on CCh contractions were not mimicked by another NADPH oxidase inhibitor (apocynin), nor the Src inhibitors PP1 or PP2, ruling out an action through the NADPH oxidase signalling pathway. Several features of the DPI-mediated suppression of agonist-evoked responses (i.e. suppression of peak magnitudes and unmasking of phasic activity) are similar to those of cyclopiazonic acid, an inhibitor of the internal Ca2+ pump. Direct measurement of microsomal Ca2+ uptake revealed that DPI modestly inhibits the internal Ca2+ pump. Conclusions and implications: DPI inhibits cholinesterase activity and the internal Ca2+ pump in tracheal smooth muscle. PMID:19788497

  5. Molecular mechanisms of hypertension: role of Nox family NADPH oxidases.

    PubMed

    Sedeek, Mona; Hébert, Richard L; Kennedy, Chris R; Burns, Kevin D; Touyz, Rhian M

    2009-03-01

    Molecular mechanisms contributing to the pathoetiology of hypertension are complex, involving many interacting systems such as signaling through G protein-coupled receptors, the renin-angiotensin system, vascular inflammation and remodeling, vascular senescence and aging and developmental programming, as highlighted in the current issue of the journal. Common to these systems is NADPH oxidase-derived reactive oxygen species (ROS). This editorial highlights current concepts relating to the production of ROS in hypertension and focuses on the Nox family NADPH oxidases, major sources of free radicals in the cardiovascular and renal systems. ROS play a major role as intracellular signaling molecules to regulate normal biological cellular responses. In pathological conditions, loss of redox homeostasis contributes to vascular oxidative damage. Recent evidence indicates that specific enzymes, the Nox family of NADPH oxidases, have the sole function of generating ROS in a highly regulated fashion in physiological conditions, and that in disease states, hyperactivation of Noxes contributes to oxidative stress and consequent cardiovascular and renal injury. The Nox family comprises seven members, Nox1-Nox7. Nox1, Nox2 (gp91phox-containing NADPH oxidase), Nox4 and Nox5 have been identified in the cardiovascular-renal systems and have been implicated in the pathophysiology of cardiovascular and renal disease. Noxes, which are differentially regulated in hypertension, are major sources of cardiovascular and renal oxidative stress. This has evoked considerable interest because of the possibilities that therapies targeted against specific Nox isoforms to decrease ROS generation or to increase nitric oxide availability or both may be useful in minimizing vascular injury and renal dysfunction, and thereby prevent or regress target organ damage associated with hypertension.

  6. Graviola inhibits hypoxia-induced NADPH oxidase activity in prostate cancer cells reducing their proliferation and clonogenicity

    PubMed Central

    Deep, Gagan; Kumar, Rahul; Jain, Anil K.; Dhar, Deepanshi; Panigrahi, Gati K.; Hussain, Anowar; Agarwal, Chapla; El-Elimat, Tamam; Sica, Vincent P.; Oberlies, Nicholas H.; Agarwal, Rajesh

    2016-01-01

    Prostate cancer (PCa) is the leading malignancy among men. Importantly, this disease is mostly diagnosed at early stages offering a unique chemoprevention opportunity. Therefore, there is an urgent need to identify and target signaling molecules with higher expression/activity in prostate tumors and play critical role in PCa growth and progression. Here we report that NADPH oxidase (NOX) expression is directly associated with PCa progression in TRAMP mice, suggesting NOX as a potential chemoprevention target in controlling PCa. Accordingly, we assessed whether NOX activity in PCa cells could be inhibited by Graviola pulp extract (GPE) that contains unique acetogenins with strong anti-cancer effects. GPE (1–5 μg/ml) treatment strongly inhibited the hypoxia-induced NOX activity in PCa cells (LNCaP, 22Rv1 and PC3) associated with a decrease in the expression of NOX catalytic and regulatory sub-units (NOX1, NOX2 and p47phox). Furthermore, GPE-mediated NOX inhibition was associated with a strong decrease in nuclear HIF-1α levels as well as reduction in the proliferative and clonogenic potential of PCa cells. More importantly, GPE treatment neither inhibited NOX activity nor showed any cytotoxicity against non-neoplastic prostate epithelial PWR-1E cells. Overall, these results suggest that GPE could be useful in the prevention of PCa progression via inhibiting NOX activity. PMID:26979487

  7. Role of catechins on ET-1 induced stimulation of PLD and NADPH oxidase activities in pulmonary smooth muscle cells: Determination of the probable mechanism by molecular docking studies.

    PubMed

    Chakraborti, Sajal; Sarkar, Jaganmay; Bhuyan, Rajabrata; Chakraborti, Tapati

    2017-12-05

    Treatment of human pulmonary artery smooth muscle cells with ET-1 stimulated PLD and NADPH oxidase activities, which were inhibited upon pretreatment with bosentan (ET-1 receptor antagonist), FIPI (PLD inhibitor), apocynin (NADPH oxidase inhibitor) and EGCG & ECG (catechins having galloyl group), but not EGC & EC (catechins devoid of galloyl group). Herein, we determined the probable mechanism by which the galloyl group containing catechins inhibit ET-1 induced stimulation of PLD activity by molecular docking analyses based on our biochemical studies. ET-1 induced stimulation of PLD activity was inhibited by SecinH3 (inhibitor of cytohesin). Arf-6 and cytohesin-1 were associated in the cell membrane, which was not inhibited by the catechins during ET-1 treatment to the cells. However, EGCG and ECG inhibited binding of GTPγS with Arf-6 even in presence of cytohesin-1. The molecular docking analyses revealed that the galloyl group containing catechins (EGCG/ECG) with cytohesin1-Arf6GDP, but not the non-galloyl-containing catechins (EGC and EC), prevents GDP/GTP exchange in Arf-6 which seems to be an important mechanism for inhibition of ET-1 induced activation of PLD and subsequently increase in NADPH oxidase activities.

  8. Hyperglycaemia promotes human brain microvascular endothelial cell apoptosis via induction of protein kinase C-ßI and prooxidant enzyme NADPH oxidase.

    PubMed

    Shao, Beili; Bayraktutan, Ulvi

    2014-01-01

    Blood-brain barrier disruption represents a key feature in hyperglycaemia-aggravated cerebral damage after an ischaemic stroke. Although the underlying mechanisms remain largely unknown, activation of protein kinase C (PKC) is thought to play a critical role. This study examined whether apoptosis of human brain microvascular endothelial cells (HBMEC) might contribute to hyperglycaemia-evoked barrier damage and assessed the specific role of PKC in this phenomenon. Treatments with hyperglycaemia (25 mM) or phorbol myristate acetate (PMA, a protein kinase C activator, 100 nM) significantly increased NADPH oxidase activity, O2 (•-) generation, proapoptotic protein Bax expression, TUNEL-positive staining and caspase-3/7 activities. Pharmacological inhibition of NADPH oxidase, PKC-a, PKC-ß or PKC-ßI via their specific inhibitors and neutralisation of O2 (•-) by a cell-permeable superoxide dismutase mimetic, MnTBAP normalised all the aforementioned increases induced by hyperglycaemia. Suppression of these PKC isoforms also negated the stimulatory effects of hyperglycaemia on the protein expression of NADPH oxidase membrane-bound components, Nox2 and p22-phox which determine the overall enzymatic activity. Silencing of PKC-ßI gene through use of specific siRNAs abolished the effects of both hyperglycaemia and PMA on endothelial cell NADPH oxidase activity, O2 (•-) production and apoptosis and consequently improved the integrity and function of an in vitro model of human cerebral barrier comprising HBMEC, astrocytes and pericytes. Hyperglycaemia-mediated apoptosis of HBMEC contributes to cerebral barrier dysfunction and is modulated by sequential activations of PKC-ßI and NADPH oxidase.

  9. Hyperglycaemia promotes human brain microvascular endothelial cell apoptosis via induction of protein kinase C-ßI and prooxidant enzyme NADPH oxidase

    PubMed Central

    Shao, Beili; Bayraktutan, Ulvi

    2014-01-01

    Blood–brain barrier disruption represents a key feature in hyperglycaemia-aggravated cerebral damage after an ischaemic stroke. Although the underlying mechanisms remain largely unknown, activation of protein kinase C (PKC) is thought to play a critical role. This study examined whether apoptosis of human brain microvascular endothelial cells (HBMEC) might contribute to hyperglycaemia-evoked barrier damage and assessed the specific role of PKC in this phenomenon. Treatments with hyperglycaemia (25 mM) or phorbol myristate acetate (PMA, a protein kinase C activator, 100 nM) significantly increased NADPH oxidase activity, O2•- generation, proapoptotic protein Bax expression, TUNEL-positive staining and caspase-3/7 activities. Pharmacological inhibition of NADPH oxidase, PKC-a, PKC-ß or PKC-ßI via their specific inhibitors and neutralisation of O2•- by a cell-permeable superoxide dismutase mimetic, MnTBAP normalised all the aforementioned increases induced by hyperglycaemia. Suppression of these PKC isoforms also negated the stimulatory effects of hyperglycaemia on the protein expression of NADPH oxidase membrane-bound components, Nox2 and p22-phox which determine the overall enzymatic activity. Silencing of PKC-ßI gene through use of specific siRNAs abolished the effects of both hyperglycaemia and PMA on endothelial cell NADPH oxidase activity, O2•- production and apoptosis and consequently improved the integrity and function of an in vitro model of human cerebral barrier comprising HBMEC, astrocytes and pericytes. Hyperglycaemia-mediated apoptosis of HBMEC contributes to cerebral barrier dysfunction and is modulated by sequential activations of PKC-ßI and NADPH oxidase. PMID:24936444

  10. Unexpected function of the phagocyte NADPH oxidase in supporting hyperglycolysis in stimulated neutrophils: key role of 6-phosphofructo-2-kinase.

    PubMed

    Baillet, Athan; Hograindleur, Marc-André; El Benna, Jamel; Grichine, Alexei; Berthier, Sylvie; Morel, Françoise; Paclet, Marie-Hélène

    2017-02-01

    The phagocyte NADPH oxidase 2 (Nox2) is an enzymatic complex that is involved in innate immunity, notably via its capacity to produce toxic reactive oxygen species. Recently, a proteomic analysis of the constitutively active Nox2 complex, isolated from neutrophil fractions, highlighted the presence of 6-phosphofructo-2-kinase (PFK-2). The purpose of this work was to study the relationship between PFK-2 and NADPH oxidase in neutrophils. Data have underlined a specific association of the active phosphorylated form of PFK-2 with Nox2 complex in stimulated neutrophils. In its active form, PFK-2 catalyzes the production of fructose-2,6-bisphosphate, which is the main allosteric activator of phosphofructo-1-kinase, the limiting enzyme in glycolysis. Pharmacologic inhibition of PFK-2 phosphorylation and cell depletion in PFK-2 by a small interfering RNA strategy led to a decrease in the glycolysis rate and a reduction in NADPH oxidase activity in stimulated cells. Surprisingly, alteration of Nox2 activity impacted the glycolysis rate, which indicated that Nox2 in neutrophils was not only required for reactive oxygen species production but was also involved in supporting the energetic metabolism increase that was induced by inflammatory conditions. PFK-2 seems to be a strategic element that links NADPH oxidase activation and glycolysis modulation, and, as such, is proposed as a potential therapeutic target in inflammatory diseases.-Baillet, A., Hograindleur, M.-A., El Benna, J., Grichine, A., Berthier, S., Morel, F., Paclet, M.-H. Unexpected function of the phagocyte NADPH oxidase in supporting hyperglycolysis in stimulated neutrophils: key role of 6-phosphofructo-2-kinase. © FASEB.

  11. New insights into the roles of NADPH oxidases in sexual development and ascospore germination in Sordaria macrospora.

    PubMed

    Dirschnabel, Daniela Elisabeth; Nowrousian, Minou; Cano-Domínguez, Nallely; Aguirre, Jesus; Teichert, Ines; Kück, Ulrich

    2014-03-01

    NADPH oxidase (NOX)-derived reactive oxygen species (ROS) act as signaling determinants that induce different cellular processes. To characterize NOX function during fungal development, we utilized the genetically tractable ascomycete Sordaria macrospora. Genome sequencing of a sterile mutant led us to identify the NADPH oxidase encoding nox1 as a gene required for fruiting body formation, regular hyphal growth, and hyphal fusion. These phenotypes are shared by nor1, lacking the NOX regulator NOR1. Further phenotypic analyses revealed a high correlation between increased ROS production and hyphal fusion deficiencies in nox1 and other sterile mutants. A genome-wide transcriptional profiling analysis of mycelia and isolated protoperithecia from wild type and nox1 revealed that nox1 inactivation affects the expression of genes related to cytoskeleton remodeling, hyphal fusion, metabolism, and mitochondrial respiration. Genetic analysis of nox2, lacking the NADPH oxidase 2 gene, nor1, and transcription factor deletion mutant ste12, revealed a strict melanin-dependent ascospore germination defect, indicating a common genetic pathway for these three genes. We report that gsa3, encoding a G-protein α-subunit, and sac1, encoding cAMP-generating adenylate cyclase, act in a separate pathway during the germination process. The finding that cAMP inhibits ascospore germination in a melanin-dependent manner supports a model in which cAMP inhibits NOX2 activity, thus suggesting a link between both pathways. Our results expand the current knowledge on the role of NOX enzymes in fungal development and provide a frame to define upstream and downstream components of the NOX signaling pathways in fungi.

  12. Role of Angiotensin II type 1 receptor on renal NAD(P)H oxidase, oxidative stress and inflammation in nitric oxide inhibition induced-hypertension.

    PubMed

    Rincón, J; Correia, D; Arcaya, J L; Finol, E; Fernández, A; Pérez, M; Yaguas, K; Talavera, E; Chávez, M; Summer, R; Romero, F

    2015-03-01

    Activation of the renin-angiotensin system (RAS), renal oxidative stress and inflammation are constantly present in experimental hypertension. Nitric oxide (NO) inhibition with N(w)-nitro-L-arginine methyl ester (L-NAME) has previously been reported to produce hypertension, increased expression of Angiotensin II (Ang II) and renal dysfunction. The use of Losartan, an Ang II type 1 receptor (AT1R) antagonist has proven to be effective reducing hypertension and renal damage; however, the mechanism by which AT1R blockade reduced kidney injury and normalizes blood pressure in this experimental model is still complete unknown. The current study was designed to test the hypothesis that AT1R activation promotes renal NAD(P)H oxidase up-regulation, oxidative stress and cytokine production during L-NAME induced-hypertension. Male Sprague-Dawley rats were distributed in three groups: L-NAME, receiving 70 mg/100ml of L-NAME, L-NAME+Los, receiving 70 mg/100ml of L-NAME and 40 mg/kg/day of Losartan; and Controls, receiving water instead of L-NAME or L-NAME and Losartan. After two weeks, L-NAME induced high blood pressure, renal overexpression of AT1R, NAD(P)H oxidase sub-units gp91, p22 and p47, increased levels of oxidative stress, interleukin-6 (IL-6) and interleukin-17 (IL-17). Also, we found increased renal accumulation of lymphocytes and macrophages. Losartan treatment abolished the renal expression of gp91, p22, p47, oxidative stress and reduced NF-κB activation and IL-6 expression. These findings indicate that NO induced-hypertension is associated with up-regulation of NADPH oxidase, oxidative stress production and overexpression of key inflammatory mediators. These events are associated with up-regulation of AT1R, as evidenced by their reversal with AT1R blocker treatment. Copyright © 2015 Elsevier Inc. All rights reserved.

  13. Absence of Proton Channels in COS-7 Cells Expressing Functional NADPH Oxidase Components

    PubMed Central

    Morgan, Deri; Cherny, Vladimir V.; Price, Marianne O.; Dinauer, Mary C.; DeCoursey, Thomas E.

    2002-01-01

    Nicotinamide adenine dinucleotide phosphate (NADPH) oxidase is an enzyme of phagocytes that produces bactericidal superoxide anion (O2 −) via an electrogenic process. Proton efflux compensates for the charge movement across the cell membrane. The proton channel responsible for the H+ efflux was thought to be contained within the gp91phox subunit of NADPH oxidase, but recent data do not support this idea (DeCoursey, T.E., V.V. Cherny, D. Morgan, B.Z. Katz, and M.C. Dinauer. 2001. J. Biol. Chem. 276:36063–36066). In this study, we investigated electrophysiological properties and superoxide production of COS-7 cells transfected with all NADPH oxidase components required for enzyme function (COSphox). The 7D5 antibody, which detects an extracellular epitope of the gp91phox protein, labeled 96–98% of COSphox cells. NADPH oxidase was functional because COSphox (but not COSWT) cells stimulated by phorbol myristate acetate (PMA) or arachidonic acid (AA) produced superoxide anion. No proton currents were detected in either wild-type COS-7 cells (COSWT) or COSphox cells studied at pHo 7.0 and pHi 5.5 or 7.0. Anion currents that decayed at voltages positive to 40 mV were the only currents observed. PMA or AA did not elicit detectable H+ current in COSWT or COSphox cells. Therefore, gp91phox does not function as a proton channel in unstimulated cells or in activated cells with a demonstrably functional oxidase. PMID:12034764

  14. Molecular Insights of p47phox Phosphorylation Dynamics in the Regulation of NADPH Oxidase Activation and Superoxide Production*

    PubMed Central

    Meijles, Daniel N.; Fan, Lampson M.; Howlin, Brendan J.; Li, Jian-Mei

    2014-01-01

    Phagocyte superoxide production by a multicomponent NADPH oxidase is important in host defense against microbial invasion. However inappropriate NADPH oxidase activation causes inflammation. Endothelial cells express NADPH oxidase and endothelial oxidative stress due to prolonged NADPH oxidase activation predisposes many diseases. Discovering the mechanism of NADPH oxidase activation is essential for developing novel treatment of these diseases. The p47phox is a key regulatory subunit of NADPH oxidase; however, due to the lack of full protein structural information, the mechanistic insight of p47phox phosphorylation in NADPH oxidase activation remains incomplete. Based on crystal structures of three functional domains, we generated a computational structural model of the full p47phox protein. Using a combination of in silico phosphorylation, molecular dynamics simulation and protein/protein docking, we discovered that the C-terminal tail of p47phox is critical for stabilizing its autoinhibited structure. Ser-379 phosphorylation disrupts H-bonds that link the C-terminal tail to the autoinhibitory region (AIR) and the tandem Src homology 3 (SH3) domains, allowing the AIR to undergo phosphorylation to expose the SH3 pocket for p22phox binding. These findings were confirmed by site-directed mutagenesis and gene transfection of p47phox−/− coronary microvascular cells. Compared with wild-type p47phox cDNA transfected cells, the single mutation of S379A completely blocked p47phox membrane translocation, binding to p22phox and endothelial O2⨪ production in response to acute stimulation of PKC. p47phox C-terminal tail plays a key role in stabilizing intramolecular interactions at rest. Ser-379 phosphorylation is a molecular switch which initiates p47phox conformational changes and NADPH oxidase-dependent superoxide production by cells. PMID:24970888

  15. P2x7 Receptor-NADPH Oxidase-Axis Mediates Protein radical Formation And Kupffer Cell Activation in Carbon Tetrachloride-Mediated Steatohepatitis in Obese Mice

    PubMed Central

    Chatterjee, Saurabh; Rana, Ritu; Corbett, Jean; Kadiiska, Maria B.; Goldstein, Joyce; Mason, Ronald P.

    2012-01-01

    While some studies show that carbon tetrachloride-mediated metabolic oxidative stress exacerbates steatohepatitic-like lesions in obese mice, the redox mechanisms that trigger the innate immune system and accentuate the inflammatory cascade remain unclear. Here we have explored the role of the purinergic receptor P2X7-NADPH oxidase axis as a primary event in recognizing the heightened release of extracellular ATP from CCl4-treated hepatocytes and generating redoxmediated Kupffer cell activation in obese mice. We found that an underlying condition of obesity led to the formation of protein radicals and post-translational nitration, primarily in Kupffer cells, at 24 h post-CCl4 administration. The free radical-mediated oxidation of cellular macromolecules, which was NADPH oxidase- and P2X7 receptor-dependent, correlated well with the release of TNF- α and MCP-2 from Kupffer cells. The Kupffer cells in CCl4-treated mice exhibited increased expression of MHC Class II proteins and showed an activated phenotype. Increased expression of MHC Class II was inhibited by the NADPH oxidase inhibitor apocynin , P2X7 receptor antagonist A438709 hydrochloride, and genetic deletions of the NADPH oxidase p47 phox subunit or the P2X7 receptor. The P2X7 receptor acted upstream of NADPH oxidase activation by up-regulating the expression of the p47 phox subunit and p47 phox binding to the membrane subunit, gp91 phox. We conclude that the P2X7 receptor is a primary mediator of oxidative stress-induced exacerbation of inflammatory liver injury in obese mice via NADPH oxidase-dependent mechanisms. PMID:22343416

  16. A novel pyrazole derivative protects from ovariectomy-induced osteoporosis through the inhibition of NADPH oxidase

    PubMed Central

    Joo, Jung Hee; Huh, Jeong-Eun; Lee, Jee Hyun; Park, Doo Ri; Lee, Yoonji; Lee, Seul Gee; Choi, Sun; Lee, Hwa Jeong; Song, Seong-Won; Jeong, Yongmi; Goo, Ja-Il; Choi, Yongseok; Baek, Hye Kyung; Yi, Sun Shin; Park, Soo Jin; Lee, Ji Eun; Ku, Sae Kwang; Lee, Won Jae; Lee, Kee-In; Lee, Soo Young; Bae, Yun Soo

    2016-01-01

    Osteoclast cells (OCs) are differentiated from bone marrow-derived macrophages (BMMs) by activation of receptor activator of nuclear factor κB (NF-κB) ligand (RANKL). Activation of NADPH oxidase (Nox) isozymes is involved in RANKL-dependent OC differentiation, implicating Nox isozymes as therapeutic targets for treatment of osteoporosis. Here, we show that a novel pyrazole derivative, Ewha-18278 has high inhibitory potency on Nox isozymes. Blocking the activity of Nox with Ewha-18278 inhibited the responses of BMMs to RANKL, including reactive oxygen species (ROS) generation, activation of mitogen-activated protein (MAP) kinases and NF-κB, and OC differentiation. To evaluate the anti-osteoporotic function of Ewha-18278, the derivative was applied to estrogen-deficient ovariectomized (OVX) ddY mice. Oral administration of Ewha-18278 (10 mg/kg/daily, 4 weeks) into the mice recovered bone mineral density, trabecular bone volume, trabecular bone length, number and thickness, compared to control OVX ddY mice. Moreover, treatment of OVX ddY mice with Ewha-18278 increased bone strength by increasing cortical bone thickness. We provide that Ewha-18278 displayed Nox inhibition and blocked the RANKL-dependent cell signaling cascade leading to reduced differentiation of OCs. Our results implicate Ewha-18278 as a novel therapeutic agent for the treatment of osteoporosis. PMID:26975635

  17. Phosphatidylinositol 3-Kinase Plays a Vital Role in Regulation of Rice Seed Vigor via Altering NADPH Oxidase Activity

    PubMed Central

    Liu, Jian; Zhou, Jun; Xing, Da

    2012-01-01

    Phosphatidylinositol 3-kinase (PI3K) has been reported to be important in normal plant growth and stress responses. In this study, it was verified that PI3K played a vital role in rice seed germination through regulating NADPH oxidase activity. Suppression of PI3K activity by inhibitors wortmannin or LY294002 could abate the reactive oxygen species (ROS) formation, which resulted in disturbance to the seed germination. And then, the signal cascades that PI3K promoted the ROS liberation was also evaluated. Diphenylene iodonium (DPI), an NADPH oxidase inhibitor, suppressed most of ROS generation in rice seed germination, which suggested that NADPH oxidase was the main source of ROS in this process. Pharmacological experiment and RT-PCR demonstrated that PI3K promoted the expression of Os rboh9. Moreover, functional analysis by native PAGE and the measurement of the 2, 3-bis-(2-methoxy-4-nitro-5-sulfophenyl)-2H-tetrazo-lium-5- carboxanilide (XTT) formazan concentration both showed that PI3K promoted the activity of NADPH oxidase. Furthermore, the western blot analysis of OsRac-1 demonstrated that the translocation of Rac-1 from cytoplasm to plasma membrane, which was known as a key factor in the assembly of NADPH oxidase, was suppressed by treatment with PI3K inhibitors, resulting in the decreased activity of NADPH oxidase. Taken together, these data favored the novel conclusion that PI3K regulated NADPH oxidase activity through modulating the recruitment of Rac-1 to plasma membrane and accelerated the process of rice seed germination. PMID:22448275

  18. Exercise training decreases NADPH oxidase activity and restores skeletal muscle mass in heart failure rats.

    PubMed

    Cunha, Telma F; Bechara, Luiz R G; Bacurau, Aline V N; Jannig, Paulo R; Voltarelli, Vanessa A; Dourado, Paulo M; Vasconcelos, Andrea R; Scavone, Cristóforo; Ferreira, Júlio C B; Brum, Patricia C

    2017-04-01

    We have recently demonstrated that NADPH oxidase hyperactivity, NF-κB activation, and increased p38 phosphorylation lead to atrophy of glycolytic muscle in heart failure (HF). Aerobic exercise training (AET) is an efficient strategy to counteract skeletal muscle atrophy in this syndrome. Therefore, we tested whether AET would regulate muscle redox balance and protein degradation by decreasing NADPH oxidase hyperactivity and reestablishing NF-κB signaling, p38 phosphorylation, and proteasome activity in plantaris muscle of myocardial infarcted-induced HF (MI) rats. Thirty-two male Wistar rats underwent MI or fictitious surgery (SHAM) and were randomly assigned into untrained (UNT) and trained (T; 8 wk of AET on treadmill) groups. AET prevented HF signals and skeletal muscle atrophy in MI-T, which showed an improved exercise tolerance, attenuated cardiac dysfunction and increased plantaris fiber cross-sectional area. To verify the role of inflammation and redox imbalance in triggering protein degradation, circulating TNF-α levels, NADPH oxidase profile, NF-κB signaling, p38 protein levels, and proteasome activity were assessed. MI-T showed a reduced TNF-α levels, NADPH oxidase activity, and Nox2 mRNA expression toward SHAM-UNT levels. The rescue of NADPH oxidase activity induced by AET in MI rats was paralleled by reducing nuclear binding activity of the NF-κB, p38 phosphorylation, atrogin-1, mRNA levels, and 26S chymotrypsin-like proteasome activity. Taken together our data provide evidence for AET improving plantaris redox homeostasis in HF associated with a decreased NADPH oxidase, redox-sensitive proteins activation, and proteasome hyperactivity further preventing atrophy. These data reinforce the role of AET as an efficient therapy for muscle wasting in HF. NEW & NOTEWORTHY This study demonstrates, for the first time, the contribution of aerobic exercise training (AET) in decreasing muscle NADPH oxidase activity associated with reduced reactive oxygen

  19. SIRPα controls the activity of the phagocyte NADPH oxidase by restricting the expression of gp91(phox).

    PubMed

    van Beek, Ellen M; Zarate, Julian Alvarez; van Bruggen, Robin; Schornagel, Karin; Tool, Anton T J; Matozaki, Takashi; Kraal, Georg; Roos, Dirk; van den Berg, Timo K

    2012-10-25

    The phagocyte NADPH oxidase mediates oxidative microbial killing in granulocytes and macrophages. However, because the reactive oxygen species produced by the NADPH oxidase can also be toxic to the host, it is essential to control its activity. Little is known about the endogenous mechanism(s) that limits NADPH oxidase activity. Here, we demonstrate that the myeloid-inhibitory receptor SIRPα acts as a negative regulator of the phagocyte NADPH oxidase. Phagocytes isolated from SIRPα mutant mice were shown to have an enhanced respiratory burst. Furthermore, overexpression of SIRPα in human myeloid cells prevented respiratory burst activation. The inhibitory effect required interactions between SIRPα and its natural ligand, CD47, as well as signaling through the SIRPα cytoplasmic immunoreceptor tyrosine-based inhibitory motifs. Suppression of the respiratory burst by SIRPα was caused by a selective repression of gp91(phox) expression, the catalytic component of the phagocyte NADPH oxidase complex. Thus, SIRPα can limit gp91(phox) expression during myeloid development, thereby controlling the magnitude of the respiratory burst in phagocytes. Copyright © 2012 The Authors. Published by Elsevier Inc. All rights reserved.

  20. NADPH oxidase/ROS-dependent PYK2 activation is involved in TNF-α-induced matrix metalloproteinase-9 expression in rat heart-derived H9c2 cells

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

    Yang, Chuen-Mao, E-mail: chuenmao@mail.cgu.edu.tw; Heart Failure Center, Division of Cardiology, Department of Internal Medicine, Chang Gung Memorial Hospital at Keelung, Keelung, Taiwan; Lee, I-Ta

    TNF-α plays a mediator role in the pathogenesis of chronic heart failure contributing to cardiac remodeling and peripheral vascular disturbances. The implication of TNF-α in inflammatory responses has been shown to be mediated through up-regulation of matrix metalloproteinase-9 (MMP-9). However, the detailed mechanisms of TNF-α-induced MMP-9 expression in rat embryonic-heart derived H9c2 cells are largely not defined. We demonstrated that in H9c2 cells, TNF-α induced MMP-9 mRNA and protein expression associated with an increase in the secretion of pro-MMP-9. TNF-α-mediated responses were attenuated by pretreatment with the inhibitor of ROS (N-acetyl-L-cysteine, NAC), NADPH oxidase [apocynin (APO) or diphenyleneiodonium chloride (DPI)],more » MEK1/2 (U0126), p38 MAPK (SB202190), JNK1/2 (SP600125), NF-κB (Bay11-7082), or PYK2 (PF-431396) and transfection with siRNA of TNFR1, p47{sup phox}, p42, p38, JNK1, p65, or PYK2. Moreover, TNF-α markedly induced NADPH oxidase-derived ROS generation in these cells. TNF-α-enhanced p42/p44 MAPK, p38 MAPK, JNK1/2, and NF-κB (p65) phosphorylation and in vivo binding of p65 to the MMP-9 promoter were inhibited by U0126, SB202190, SP600125, NAC, DPI, or APO. In addition, TNF-α-mediated PYK2 phosphorylation was inhibited by NAC, DPI, or APO. PYK2 inhibition could reduce TNF-α-stimulated MAPKs and NF-κB activation. Thus, in H9c2 cells, we are the first to show that TNF-α-induced MMP-9 expression is mediated through a TNFR1/NADPH oxidase/ROS/PYK2/MAPKs/NF-κB cascade. We demonstrated that NADPH oxidase-derived ROS generation is involved in TNF-α-induced PYK2 activation in these cells. Understanding the regulation of MMP-9 expression and NADPH oxidase activation by TNF-α on H9c2 cells may provide potential therapeutic targets of chronic heart failure. - Highlights: • TNF-α induces MMP-9 secretion and expression via a TNFR1-dependent pathway. • TNF-α induces ROS/PYK2-dependent MMP-9 expression in H9c2 cells. • TNF

  1. Absence of proton channels in COS-7 cells expressing functional NADPH oxidase components.

    PubMed

    Morgan, Deri; Cherny, Vladimir V; Price, Marianne O; Dinauer, Mary C; DeCoursey, Thomas E

    2002-06-01

    Nicotinamide adenine dinucleotide phosphate (NADPH) oxidase is an enzyme of phagocytes that produces bactericidal superoxide anion (O(2)(-)) via an electrogenic process. Proton efflux compensates for the charge movement across the cell membrane. The proton channel responsible for the H(+) efflux was thought to be contained within the gp91(phox) subunit of NADPH oxidase, but recent data do not support this idea (DeCoursey, T.E., V.V. Cherny, D. Morgan, B.Z. Katz, and M.C. Dinauer. 2001. J. Biol. Chem. 276:36063-36066). In this study, we investigated electrophysiological properties and superoxide production of COS-7 cells transfected with all NADPH oxidase components required for enzyme function (COS(phox)). The 7D5 antibody, which detects an extracellular epitope of the gp91(phox) protein, labeled 96-98% of COS(phox) cells. NADPH oxidase was functional because COS(phox) (but not COS(WT)) cells stimulated by phorbol myristate acetate (PMA) or arachidonic acid (AA) produced superoxide anion. No proton currents were detected in either wild-type COS-7 cells (COS(WT)) or COS(phox) cells studied at pH(o) 7.0 and pH(i) 5.5 or 7.0. Anion currents that decayed at voltages positive to 40 mV were the only currents observed. PMA or AA did not elicit detectable H(+) current in COS(WT) or COS(phox) cells. Therefore, gp91(phox) does not function as a proton channel in unstimulated cells or in activated cells with a demonstrably functional oxidase.

  2. Nox4 NADPH oxidase mediates oxidative stress and apoptosis caused by TNF-α in cerebral vascular endothelial cells

    PubMed Central

    Basuroy, Shyamali; Bhattacharya, Sujoy; Leffler, Charles W.; Parfenova, Helena

    2009-01-01

    Inflammatory brain disease may damage cerebral vascular endothelium leading to cerebral blood flow dysregulation. The proinflammatory cytokine TNF-α causes oxidative stress and apoptosis in cerebral microvascular endothelial cells (CMVEC) from newborn pigs. We investigated contribution of major cellular sources of reactive oxygen species to endothelial inflammatory response. Nitric oxide synthase and xanthine oxidase inhibitors (Nω-nitro-l-arginine and allopurinol) had no effect, while mitochondrial electron transport inhibitors (CCCP, 2-thenoyltrifluoroacetone, and rotenone) attenuated TNF-α-induced superoxide (O2•−) and apoptosis. NADPH oxidase inhibitors (diphenylene iodonium and apocynin) greatly reduced TNF-α-evoked O2•− generation and apoptosis. TNF-α rapidly increased NADPH oxidase activity in CMVEC. Nox4, the cell-specific catalytic subunit of NADPH oxidase, is highly expressed in CMVEC, contributes to basal O2•− production, and accounts for a burst of oxidative stress in response to TNF-α. Nox4 small interfering RNA, but not Nox2, knockdown prevented oxidative stress and apoptosis caused by TNF-α in CMVEC. Nox4 is colocalized with HO-2, the constitutive isoform of heme oxygenase (HO), which is critical for endothelial protection against TNF-α toxicity. The products of HO activity, bilirubin and carbon monoxide (CO, as a CO-releasing molecule, CORM-A1), inhibited Nox4-generated O2•− and apoptosis caused by TNF-α stimulation. We conclude that Nox4 is the primary source of inflammation- and TNF-α-induced oxidative stress leading to apoptosis in brain endothelial cells. The ability of CO and bilirubin to combat TNF-α-induced oxidative stress by inhibiting Nox4 activity and/or by O2•− scavenging, taken together with close intracellular compartmentalization of HO-2 and Nox4 in cerebral vascular endothelium, may contribute to HO-2 cytoprotection against inflammatory cerebrovascular disease. PMID:19118162

  3. New Insights Into the Roles of NADPH Oxidases in Sexual Development and Ascospore Germination in Sordaria macrospora

    PubMed Central

    Dirschnabel, Daniela Elisabeth; Nowrousian, Minou; Cano-Domínguez, Nallely; Aguirre, Jesus; Teichert, Ines; Kück, Ulrich

    2014-01-01

    NADPH oxidase (NOX)-derived reactive oxygen species (ROS) act as signaling determinants that induce different cellular processes. To characterize NOX function during fungal development, we utilized the genetically tractable ascomycete Sordaria macrospora. Genome sequencing of a sterile mutant led us to identify the NADPH oxidase encoding nox1 as a gene required for fruiting body formation, regular hyphal growth, and hyphal fusion. These phenotypes are shared by ∆nor1, lacking the NOX regulator NOR1. Further phenotypic analyses revealed a high correlation between increased ROS production and hyphal fusion deficiencies in ∆nox1 and other sterile mutants. A genome-wide transcriptional profiling analysis of mycelia and isolated protoperithecia from wild type and ∆nox1 revealed that nox1 inactivation affects the expression of genes related to cytoskeleton remodeling, hyphal fusion, metabolism, and mitochondrial respiration. Genetic analysis of ∆nox2, lacking the NADPH oxidase 2 gene, ∆nor1, and transcription factor deletion mutant ∆ste12, revealed a strict melanin-dependent ascospore germination defect, indicating a common genetic pathway for these three genes. We report that gsa3, encoding a G-protein α-subunit, and sac1, encoding cAMP-generating adenylate cyclase, act in a separate pathway during the germination process. The finding that cAMP inhibits ascospore germination in a melanin-dependent manner supports a model in which cAMP inhibits NOX2 activity, thus suggesting a link between both pathways. Our results expand the current knowledge on the role of NOX enzymes in fungal development and provide a frame to define upstream and downstream components of the NOX signaling pathways in fungi. PMID:24407906

  4. Nox4 NADPH oxidase-derived reactive oxygen species, via endogenous carbon monoxide, promote survival of brain endothelial cells during TNF-α-induced apoptosis

    PubMed Central

    Basuroy, Shyamali; Tcheranova, Dilyara; Bhattacharya, Sujoy; Leffler, Charles W.

    2011-01-01

    We investigated the role of reactive oxygen species (ROS) in promoting cell survival during oxidative stress induced by the inflammatory mediator tumor necrosis factor-α (TNF-α) in cerebral microvascular endothelial cells (CMVEC) from newborn piglets. Nox4 is the major isoform of NADPH oxidase responsible for TNF-α-induced oxidative stress and apoptosis in CMVEC. We present novel data that Nox4 NADPH oxidase-derived ROS also initiate a cell survival mechanism by increasing production of a gaseous antioxidant mediator carbon monoxide (CO) by constitutive heme oxygenase-2 (HO-2). TNF-α rapidly enhanced endogenous CO production in a superoxide- and NADPH oxidase-dependent manner in CMVEC with innate, but not with small interfering RNA (siRNA)-downregulated Nox4 activity. CORM-A1, a CO-releasing compound, inhibited Nox4-mediated ROS production and enhanced cell survival in TNF-α-challenged CMVEC. The ROS-induced CO-mediated survival mechanism requires functional interactions between the protein kinase B/Akt and extracellular signal-related kinase (ERK)/p38 MAPK signaling pathways activated by TNF-α. In Akt siRNA-transfected CMVEC and in cells with pharmacologically inhibited Akt, Erk1/2, and p38 mitogen-activated protein kinase (MAPK) activities, CORM-A1 was no longer capable of blocking Nox4 activation and apoptosis caused by TNF-α. Overall, Nox4 NADPH oxidase-derived ROS initiate both death and survival pathways in TNF-α-challenged CMVEC. The ROS-dependent cell survival pathway is mediated by an endogenous antioxidant CO, which inhibits Nox4 activation via a mechanism that includes Akt, ERK1/2, and p38 MAPK signaling pathways. The ability of CO to inhibit TNF-α-induced ERK1/2 and p38 MAPK activities in an Akt-dependent manner appears to be the key element in ROS-dependent survival of endothelial cells during TNF-α-mediated brain inflammatory disease. PMID:21123734

  5. Role of xanthine oxidoreductase and NAD(P)H oxidase in endothelial superoxide production in response to oscillatory shear stress

    NASA Technical Reports Server (NTRS)

    McNally, J. Scott; Davis, Michael E.; Giddens, Don P.; Saha, Aniket; Hwang, Jinah; Dikalov, Sergey; Jo, Hanjoong; Harrison, David G.

    2003-01-01

    Oscillatory shear stress occurs at sites of the circulation that are vulnerable to atherosclerosis. Because oxidative stress contributes to atherosclerosis, we sought to determine whether oscillatory shear stress increases endothelial production of reactive oxygen species and to define the enzymes responsible for this phenomenon. Bovine aortic endothelial cells were exposed to static, laminar (15 dyn/cm2), and oscillatory shear stress (+/-15 dyn/cm2). Oscillatory shear increased superoxide (O2.-) production by more than threefold over static and laminar conditions as detected using electron spin resonance (ESR). This increase in O2*- was inhibited by oxypurinol and culture of endothelial cells with tungsten but not by inhibitors of other enzymatic sources. Oxypurinol also prevented H2O2 production in response to oscillatory shear stress as measured by dichlorofluorescin diacetate and Amplex Red fluorescence. Xanthine-dependent O2*- production was increased in homogenates of endothelial cells exposed to oscillatory shear stress. This was associated with decreased xanthine dehydrogenase (XDH) protein levels and enzymatic activity resulting in an elevated ratio of xanthine oxidase (XO) to XDH. We also studied endothelial cells lacking the p47phox subunit of the NAD(P)H oxidase. These cells exhibited dramatically depressed O2*- production and had minimal XO protein and activity. Transfection of these cells with p47phox restored XO protein levels. Finally, in bovine aortic endothelial cells, prolonged inhibition of the NAD(P)H oxidase with apocynin decreased XO protein levels and prevented endothelial cell stimulation of O2*- production in response to oscillatory shear stress. These data suggest that the NAD(P)H oxidase maintains endothelial cell XO levels and that XO is responsible for increased reactive oxygen species production in response to oscillatory shear stress.

  6. NADPH oxidase: an enzyme for multicellularity?

    PubMed

    Lalucque, Hervé; Silar, Philippe

    2003-01-01

    Multicellularity has evolved several times during the evolution of eukaryotes. One evolutionary pressure that permits multicellularity relates to the division of work, where one group of cells functions as nutrient providers and the other in specialized roles such as defence or reproduction. This requires signalling systems to ensure harmonious development of multicellular structures. Here, we show that NADPH oxidases are specifically present in organisms that differentiate multicellular structures during their life cycle and are absent from unicellular life forms. The biochemical properties of these enzymes make them ideal candidates for a role in intercellular signalling.

  7. NADPH oxidase activity and reactive oxygen species production in brain and kidney of adult male hypertensive Ren-2 transgenic rats.

    PubMed

    Vokurková, M; Rauchová, H; Řezáčová, L; Vaněčková, I; Zicha, J

    2015-01-01

    Hypothalamic paraventricular nucleus (PVN) and rostral ventrolateral medulla (RVLM) play an important role in brain control of blood pressure (BP). One of the important mechanisms involved in the pathogenesis of hypertension is the elevation of reactive oxygen species (ROS) production by nicotine adenine dinucleotide phosphate (NADPH) oxidase. The aim of our present study was to investigate NADPH oxidase-mediated superoxide (O(2)(-)) production and to search for the signs of lipid peroxidation in hypothalamus and medulla oblongata as well as in renal medulla and cortex of hypertensive male rats transgenic for the murine Ren-2 renin gene (Ren-2 TGR) and their age-matched normotensive controls - Hannover Sprague Dawley rats (HanSD). We found no difference in the activity of NADPH oxidase measured as a lucigenin-mediated O(2)(-) production in the hypothalamus and medulla oblongata. However, we observed significantly elevated NADPH oxidase in both renal cortex and medulla of Ren-2 TGR compared with HanSD. Losartan (LOS) treatment (10 mg/kg body weight/day) for 2 months (Ren-2 TGR+LOS) did not change NADPH oxidase-dependent O(2)(-) production in the kidney. We detected significantly elevated indirect markers of lipid peroxidation measured as thiobarbituric acid-reactive substances (TBARS) in Ren-2 TGR, while they were significantly decreased in Ren-2 TGR+LOS. In conclusion, the present study shows increased NADPH oxidase activities in renal cortex and medulla with significantly increased TBARS in renal cortex. No significant changes of NADPH oxidase and markers of lipid peroxidation were detected in the studied brain regions.

  8. NADPH oxidase-2 inhibition restores contractility and intracellular calcium handling and reduces arrhythmogenicity in dystrophic cardiomyopathy

    PubMed Central

    Gonzalez, Daniel R.; Treuer, Adriana V.; Lamirault, Guillaume; Mayo, Vera; Cao, Yenong; Dulce, Raul A.

    2014-01-01

    Duchenne muscular dystrophy may affect cardiac muscle, producing a dystrophic cardiomyopathy in humans and the mdx mouse. We tested the hypothesis that oxidative stress participates in disrupting calcium handling and contractility in the mdx mouse with established cardiomyopathy. We found increased expression (fivefold) of the NADPH oxidase (NOX) 2 in the mdx hearts compared with wild type, along with increased superoxide production. Next, we tested the impact of NOX2 inhibition on contractility and calcium handling in isolated cardiomyocytes. Contractility was decreased in mdx myocytes compared with wild type, and this was restored toward normal by pretreating with apocynin. In addition, the amplitude of evoked intracellular Ca2+ concentration transients that was diminished in mdx myocytes was also restored with NOX2 inhibition. Total sarcoplasmic reticulum (SR) Ca2+ content was reduced in mdx hearts and normalized by apocynin treatment. Additionally, NOX2 inhibition decreased the production of spontaneous diastolic calcium release events and decreased the SR calcium leak in mdx myocytes. In addition, nitric oxide (NO) synthase 1 (NOS-1) expression was increased eightfold in mdx hearts compared with wild type. Nevertheless, cardiac NO production was reduced. To test whether this paradox implied NOS-1 uncoupling, we treated cardiac myocytes with exogenous tetrahydrobioterin, along with the NOX inhibitor VAS2870. These agents restored NO production and phospholamban phosphorylation in mdx toward normal. Together, these results demonstrate that, in mdx hearts, NOX2 inhibition improves the SR calcium handling and contractility, partially by recoupling NOS-1. These findings reveal a new layer of nitroso-redox imbalance in dystrophic cardiomyopathy. PMID:25015966

  9. Crystal structures and atomic model of NADPH oxidase.

    PubMed

    Magnani, Francesca; Nenci, Simone; Millana Fananas, Elisa; Ceccon, Marta; Romero, Elvira; Fraaije, Marco W; Mattevi, Andrea

    2017-06-27

    NADPH oxidases (NOXs) are the only enzymes exclusively dedicated to reactive oxygen species (ROS) generation. Dysregulation of these polytopic membrane proteins impacts the redox signaling cascades that control cell proliferation and death. We describe the atomic crystal structures of the catalytic flavin adenine dinucleotide (FAD)- and heme-binding domains of Cylindrospermum stagnale NOX5. The two domains form the core subunit that is common to all seven members of the NOX family. The domain structures were then docked in silico to provide a generic model for the NOX family. A linear arrangement of cofactors (NADPH, FAD, and two membrane-embedded heme moieties) injects electrons from the intracellular side across the membrane to a specific oxygen-binding cavity on the extracytoplasmic side. The overall spatial organization of critical interactions is revealed between the intracellular loops on the transmembrane domain and the NADPH-oxidizing dehydrogenase domain. In particular, the C terminus functions as a toggle switch, which affects access of the NADPH substrate to the enzyme. The essence of this mechanistic model is that the regulatory cues conformationally gate NADPH-binding, implicitly providing a handle for activating/deactivating the very first step in the redox chain. Such insight provides a framework to the discovery of much needed drugs that selectively target the distinct members of the NOX family and interfere with ROS signaling.

  10. Seizure activity results in calcium- and mitochondria-independent ROS production via NADPH and xanthine oxidase activation

    PubMed Central

    Kovac, S; Domijan, A-M; Walker, M C; Abramov, A Y

    2014-01-01

    Seizure activity has been proposed to result in the generation of reactive oxygen species (ROS), which then contribute to seizure-induced neuronal damage and eventually cell death. Although the mechanisms of seizure-induced ROS generation are unclear, mitochondria and cellular calcium overload have been proposed to have a crucial role. We aim to determine the sources of seizure-induced ROS and their contribution to seizure-induced cell death. Using live cell imaging techniques in glioneuronal cultures, we show that prolonged seizure-like activity increases ROS production in an NMDA receptor-dependent manner. Unexpectedly, however, mitochondria did not contribute to ROS production during seizure-like activity. ROS were generated primarily by NADPH oxidase and later by xanthine oxidase (XO) activity in a calcium-independent manner. This calcium-independent neuronal ROS production was accompanied by an increase in intracellular [Na+] through NMDA receptor activation. Inhibition of NADPH or XO markedly reduced seizure-like activity-induced neuronal apoptosis. These findings demonstrate a critical role for ROS in seizure-induced neuronal cell death and identify novel therapeutic targets. PMID:25275601

  11. Acupuncture elicits neuroprotective effect by inhibiting NAPDH oxidase-mediated reactive oxygen species production in cerebral ischaemia.

    PubMed

    Shi, Guang-Xia; Wang, Xue-Rui; Yan, Chao-Qun; He, Tian; Yang, Jing-Wen; Zeng, Xiang-Hong; Xu, Qian; Zhu, Wen; Du, Si-Qi; Liu, Cun-Zhi

    2015-12-10

    In the current study, we aimed to investigate whether NADPH oxidase, a major ROS-producing enzyme, was involved in the antioxidant effect of acupuncture on cognitive impairment after cerebral ischaemia. The cognitive function, infract size, neuron cell loss, level of superoxide anion and expression of NADPH oxidase subunit in hippocampus of two-vessel occlusion (2VO) rats were determined after 2-week acupuncture. Furthermore, the cognitive function and production of O2(-) were determined in the presence and absence of NADPH oxidase agonist (TBCA) and antagonist (Apocynin). The effect of acupuncture on cognitive function after cerebral ischaemia in gp91phox-KO mice was evaluated by Morris water maze. Acupuncture reduced infarct size, attenuated overproduction of O2(-), and reversed consequential cognitive impairment and neuron cell loss in 2VO rats. The elevations of gp91phox and p47phox after 2VO were significantly decreased after acupuncture treatment. However, no differences of gp91phox mRNA were found among any experimental groups. Furthermore, these beneficial effects were reversed by TBCA, whereas apocynin mimicked the effect of acupuncture by improving cognitive function and decreasing O2(-) generation. Acupuncture failed to improve the memory impairment in gp91phox KO mice. Full function of the NADPH oxidase enzyme plays an important role in neuroprotective effects against cognitive impairment via inhibition of NAPDH oxidase-mediated oxidative stress.

  12. Ozone affects pollen viability and NAD(P)H oxidase release from Ambrosia artemisiifolia pollen.

    PubMed

    Pasqualini, Stefania; Tedeschini, Emma; Frenguelli, Giuseppe; Wopfner, Nicole; Ferreira, Fatima; D'Amato, Gennaro; Ederli, Luisa

    2011-10-01

    Air pollution is frequently proposed as a cause of the increased incidence of allergy in industrialised countries. We investigated the impact of ozone (O(3)) on reactive oxygen species (ROS) and allergen content of ragweed pollen (Ambrosia artemisiifolia). Pollen was exposed to acute O(3) fumigation, with analysis of pollen viability, ROS and nitric oxide (NO) content, activity of nicotinamide adenine dinucleotide phosphate (NAD[P]H) oxidase, and expression of major allergens. There was decreased pollen viability after O(3) fumigation, which indicates damage to the pollen membrane system, although the ROS and NO contents were not changed or were only slightly induced, respectively. Ozone exposure induced a significant enhancement of the ROS-generating enzyme NAD(P)H oxidase. The expression of the allergen Amb a 1 was not affected by O(3), determined from the mRNA levels of the major allergens. We conclude that O(3) can increase ragweed pollen allergenicity through stimulation of ROS-generating NAD(P)H oxidase. Copyright © 2011 Elsevier Ltd. All rights reserved.

  13. 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.

  14. NADPH oxidase-mediated generation of reactive oxygen species is critically required for survival of undifferentiated human promyelocytic leukemia cell line HL-60.

    PubMed

    Dong, Jing-Mei; Zhao, Sheng-Guo; Huang, Guo-Yin; Liu, Qing

    2004-06-01

    Nicotinamide adenine dinucleotide phosphate oxidase (NADPH oxidase) mediated generation of reactive oxygen species (ROS) was originally identified as the powerful host defense machinery against microorganism in phagocytes. But recent reports indicated that some non-phagocytic cells also have the NADPH oxidase activity, and the ROS produced by it may act as cell signal molecule. But as far as today, whether the NADPH oxidase also plays similar role in phagocyte has not been paid much attention. Utilizing the undifferentiated HL-60 promyelocytic leukemia cells as a model, the aim of the present study was to determine whether NADPH oxidase plays a role on ROS generation in undifferentiated HL-60, and the ROS mediated by it was essential for cell's survival. For the first time, we verified that the release of ROS in undifferentiated HL-60 was significantly increased by the stimulation with Calcium ionophore or opsonized zymosan, which are known to trigger respiration burst in phagocytes by NADPH oxidase pathway. Diphenylene iodonium (DPI) or apocynin (APO), two inhibitors of NADPH oxidase, significantly suppressed the increasing of ROS caused by opsonized zymosan. Cell survival assay and fluorescence double dyeing with acridine orange and ethidium bromide showed that DPI and APO, as well as superoxide dismutase (SOD) and catalase (CAT) concentration-dependently decreased the viability of undifferentiated HL-60 cells, whereas exogenous H2O2 can rescue the cells from death obviously. Our results suggested that the ROS, generated by NADPH oxidase play an essential role in the survival of undifferentiated HL-60 cells.

  15. Genetic Phagocyte NADPH Oxidase Deficiency Enhances Nonviable Candida albicans-Induced Inflammation in Mouse Lungs.

    PubMed

    Endo, Daiki; Fujimoto, Kenta; Hirose, Rika; Yamanaka, Hiroko; Homme, Mizuki; Ishibashi, Ken-Ichi; Miura, Noriko; Ohno, Naohito; Aratani, Yasuaki

    2017-02-01

    Patients with chronic granulomatous disease (CGD) have mutated phagocyte NADPH oxidase, resulting in reduced production of reactive oxygen species (ROS). While the mechanism underlying hyperinfection in CGD is well understood, the basis for inflammatory disorders that arise in the absence of evident infection has not been fully explained. This study aimed to evaluate the effect of phagocyte NADPH oxidase deficiency on lung inflammation induced by nonviable Candida albicans (nCA). Mice deficient in this enzyme (CGD mice) showed more severe neutrophilic pneumonia than nCA-treated wild-type mice, which exhibited significantly higher lung concentrations of interleukin (IL)-1β, tumor necrosis factor (TNF)-α, and keratinocyte-derived chemokine (KC). Neutralization of these proinflammatory mediators significantly reduced neutrophil infiltration. In vitro, production of IL-1β and TNF-α from neutrophils and that of KC from macrophages was enhanced in nCA-stimulated neutrophils from CGD mice. Expression of IL-1β mRNA was higher in the stimulated CGD neutrophils than in the stimulated wild-type cells, concomitant with upregulation of nuclear factor (NF)-κB and its upstream regulator extracellular-signal regulated kinase (ERK) 1/2. Pretreatment with an NADPH oxidase inhibitor significantly enhanced IL-1β production in the wild-type neutrophils stimulated with nCA. These results suggest that lack of ROS production because of NADPH oxidase deficiency results in the production of higher levels of proinflammatory mediators from neutrophils and macrophages, which may at least partly contribute to the exacerbation of nCA-induced lung inflammation in CGD mice.

  16. Genetic Targeting or Pharmacologic Inhibition of NADPH Oxidase Nox4 Provides Renoprotection in Long-Term Diabetic Nephropathy

    PubMed Central

    Jha, Jay C.; Gray, Stephen P.; Barit, David; Okabe, Jun; El-Osta, Assam; Namikoshi, Tamehachi; Thallas-Bonke, Vicki; Wingler, Kirstin; Szyndralewiez, Cedric; Heitz, Freddy; Touyz, Rhian M.; Cooper, Mark E.; Schmidt, Harald H.H.W.

    2014-01-01

    Diabetic nephropathy may occur, in part, as a result of intrarenal oxidative stress. NADPH oxidases comprise the only known dedicated reactive oxygen species (ROS)–forming enzyme family. In the rodent kidney, three isoforms of the catalytic subunit of NADPH oxidase are expressed (Nox1, Nox2, and Nox4). Here we show that Nox4 is the main source of renal ROS in a mouse model of diabetic nephropathy induced by streptozotocin administration in ApoE−/− mice. Deletion of Nox4, but not of Nox1, resulted in renal protection from glomerular injury as evidenced by attenuated albuminuria, preserved structure, reduced glomerular accumulation of extracellular matrix proteins, attenuated glomerular macrophage infiltration, and reduced renal expression of monocyte chemoattractant protein-1 and NF-κB in streptozotocin-induced diabetic ApoE−/− mice. Importantly, administration of the most specific Nox1/4 inhibitor, GKT137831, replicated these renoprotective effects of Nox4 deletion. In human podocytes, silencing of the Nox4 gene resulted in reduced production of ROS and downregulation of proinflammatory and profibrotic markers that are implicated in diabetic nephropathy. Collectively, these results identify Nox4 as a key source of ROS responsible for kidney injury in diabetes and provide proof of principle for an innovative small molecule approach to treat and/or prevent chronic kidney failure. PMID:24511132

  17. Low-Dose Dextromethorphan, a NADPH Oxidase Inhibitor, Reduces Blood Pressure and Enhances Vascular Protection in Experimental Hypertension

    PubMed Central

    Wu, Tao-Cheng; Chao, Chih-Yu; Lin, Shing-Jong; Chen, Jaw-Wen

    2012-01-01

    Background Vascular oxidative stress may be increased with age and aggravate endothelial dysfunction and vascular injury in hypertension. This study aimed to investigate the effects of dextromethorphan (DM), a NADPH oxidase inhibitor, either alone or in combination treatment, on blood pressure (BP) and vascular protection in aged spontaneous hypertensive rats (SHRs). Methodology/Principal Findings Eighteen-week-old WKY rats and SHRs were housed for 2 weeks. SHRs were randomly assigned to one of the 12 groups: untreated; DM monotherapy with 1, 5 or 25 mg/kg/day; amlodipine (AM, a calcium channel blocker) monotherapy with 1 or 5 mg/kg/day; and combination therapy of DM 1, 5 or 25 mg/kg/day with AM 1 or 5 mg/kg/day individually for 4 weeks. The in vitro effects of DM were also examined. In SHRs, AM monotherapy dose-dependently reduced arterial systolic BP. DM in various doses significantly and similarly reduced arterial systolic BP. Combination of DM with AM gave additive effects on BP reduction. DM, either alone or in combination with AM, improved aortic endothelial function indicated by ex vivo acetylcholine-induced relaxation. The combination of low-dose DM with AM gave most significant inhibition on aortic wall thickness in SHRs. Plasma total antioxidant status was significantly increased by all the therapies except for the combination of high-dose DM with high-dose AM. Serum nitrite and nitrate level was significantly reduced by AM but not by DM or the combination of DM with AM. Furthermore, in vitro treatment with DM reduced angiotensin II-induced reactive oxygen species and NADPH oxidase activation in human aortic endothelial cells. Conclusions/Significance Treatment of DM reduced BP and enhanced vascular protection probably by inhibiting vascular NADPH oxidase in aged hypertensive animals with or without AM treatment. It provides the potential rationale to a novel combination treatment with low-dose DM and AM in clinical hypertension. PMID:23049937

  18. The arachidonic acid-binding protein S100A8/A9 promotes NADPH oxidase activation by interaction with p67phox and Rac-2.

    PubMed

    Kerkhoff, Claus; Nacken, Wolfgang; Benedyk, Malgorzata; Dagher, Marie Claire; Sopalla, Claudia; Doussiere, Jacques

    2005-03-01

    The Ca2+- and arachidonic acid-binding S100A8/A9 protein complex was recently identified by in vitro studies as a novel partner of the phagocyte NADPH oxidase. The present study demonstrated its functional relevance by the impaired oxidase activity in neutrophil-like NB4 cells, after specific blockage of S100A9 expression, and bone marrow polymorphonuclear neutrophils from S100A9-/- mice. The impaired oxidase activation could also be mimicked in a cell-free system by pretreatment of neutrophil cytosol with an S100A9-specific antibody. Further analyses gave insights into the molecular mechanisms by which S100A8/A9 promoted NADPH oxidase activation. In vitro analysis of oxidase activation as well as protein-protein interaction studies revealed that S100A8 is the privileged interaction partner for the NADPH oxidase complex since it bound to p67phox and Rac, whereas S100A9 did interact with neither p67phox nor p47phox. Moreover, S100A8/A9 transferred the cofactor arachidonic acid to NADPH oxidase as shown by the impotence of a mutant S100A8/A9 complex unable to bind arachidonic acid to enhance NADPH oxidase activity. It is concluded that S100A8/A9 plays an important role in phagocyte NADPH oxidase activation.

  19. Molecular Interface of S100A8 with Cytochrome b558 and NADPH Oxidase Activation

    PubMed Central

    Berthier, Sylvie; Hograindleur, Marc-André; Paclet, Marie-Hélène; Polack, Benoît; Morel, Françoise

    2012-01-01

    S100A8 and S100A9 are two calcium binding Myeloid Related Proteins, and important mediators of inflammatory diseases. They were recently introduced as partners for phagocyte NADPH oxidase regulation. However, the precise mechanism of their interaction remains elusive. We had for aim (i) to evaluate the impact of S100 proteins on NADPH oxidase activity; (ii) to characterize molecular interaction of either S100A8, S100A9, or S100A8/S100A9 heterocomplex with cytochrome b 558; and (iii) to determine the S100A8 consensus site involved in cytochrome b 558/S100 interface. Recombinant full length or S100A9-A8 truncated chimera proteins and ExoS-S100 fusion proteins were expressed in E. coli and in P. aeruginosa respectively. Our results showed that S100A8 is the functional partner for NADPH oxidase activation contrary to S100A9, however, the loading with calcium and a combination with phosphorylated S100A9 are essential in vivo. Endogenous S100A9 and S100A8 colocalize in differentiated and PMA stimulated PLB985 cells, with Nox2/gp91phox and p22phox. Recombinant S100A8, loaded with calcium and fused with the first 129 or 54 N-terminal amino acid residues of the P. aeruginosa ExoS toxin, induced a similar oxidase activation in vitro, to the one observed with S100A8 in the presence of S100A9 in vivo. This suggests that S100A8 is the essential component of the S100A9/S100A8 heterocomplex for oxidase activation. In this context, recombinant full-length rS100A9-A8 and rS100A9-A8 truncated 90 chimera proteins as opposed to rS100A9-A8 truncated 86 and rS100A9-A8 truncated 57 chimeras, activate the NADPH oxidase function of purified cytochrome b 558 suggesting that the C-terminal region of S100A8 is directly involved in the molecular interface with the hemoprotein. The data point to four strategic 87HEES90 amino acid residues of the S100A8 C-terminal sequence that are involved directly in the molecular interaction with cytochrome b558 and then in the phagocyte NADPH oxidase

  20. Differential roles of NADPH oxidases in vascular physiology and pathophysiology

    PubMed Central

    Amanso, Angelica M.; Griendling, Kathy K.

    2012-01-01

    Reactive oxygen species (ROS) are produced by all vascular cells and regulate the major physiological functions of the vasculature. Production and removal of ROS are tightly controlled and occur in discrete subcellular locations, allowing for specific, compartmentalized signaling. Among the many sources of ROS in the vessel wall, NADPH oxidases are implicated in physiological functions such as control of vasomotor tone, regulation of extracellular matrix and phenotypic modulation of vascular smooth muscle cells. They are involved in the response to injury, whether as an oxygen sensor during hypoxia, as a regulator of protein processing, as an angiogenic stimulus, or as a mechanism of wound healing. These enzymes have also been linked to processes leading to disease development, including migration, proliferation, hypertrophy, apoptosis and autophagy. As a result, NADPH oxidases participate in atherogenesis, systemic and pulmonary hypertension and diabetic vascular disease. The role of ROS in each of these processes and diseases is complex, and a more full understanding of the sources, targets, cell-specific responses and counterbalancing mechanisms is critical for the rational development of future therapeutics. PMID:22202108

  1. Interactions of NADPH oxidase, renin-angiotensin-aldosterone system and reactive oxygen species in mequindox-mediated aldosterone secretion in Wistar rats.

    PubMed

    Huang, Xian-Ju; Wang, Xu; Ihsan, Awais; Liu, Qin; Xue, Xi-Juan; Su, Shi-Jia; Yang, Chun-Hui; Zhou, Wen; Yuan, Zong-Hui

    2010-10-05

    High doses of mequindox (MEQ) are associated with oxidative stress and pathological toxicity in the kidney. In this study, we demonstrated long term effects of MEQ on intra- or extra-adrenal renin-angiotensin-aldosterone system (RAAS) in vivo. RAAS plays a major role in aldosterone secretion. High doses of MEQ in the diet for 180 days in male rats led to inhibition of intra- and extra-adrenal RAAS, concident with down-regulation of Na(+)/K(+)-ATPase (NAKA) and mineralocorticoid receptor (MR), the downstream of aldosterone action. Significant changes of malondialdehyde (MDA), reduced glutathione (GSH), and superoxide dismutase (SOD) in kidney were also observed in the high doses (110, 275mg/kg) groups. The mRNA levels of most subunits of NADPH oxidase were significantly upregulated at low doses (25-110mg/kg) but the upregulation was diminished at higher doses in both kidney and adrenal gland, indicating a complicated and contradictory effect of MEQ on NADPH. These results highlight the complex interactions of drug metabolism, RAAS, NADPH oxidase and oxidative stress in response to MEQ-induced tissue toxicity and aldosterone secretion. Copyright 2010 Elsevier Ireland Ltd. All rights reserved.

  2. Oleic, Linoleic and Linolenic Acids Increase ROS Production by Fibroblasts via NADPH Oxidase Activation

    PubMed Central

    Hatanaka, Elaine; Dermargos, Alexandre; Hirata, Aparecida Emiko; Vinolo, Marco Aurélio Ramirez; Carpinelli, Angelo Rafael; Newsholme, Philip; Armelin, Hugo Aguirre; Curi, Rui

    2013-01-01

    The effect of oleic, linoleic and γ-linolenic acids on ROS production by 3T3 Swiss and Rat 1 fibroblasts was investigated. Using lucigenin-amplified chemiluminescence, a dose-dependent increase in extracellular superoxide levels was observed during the treatment of fibroblasts with oleic, linoleic and γ-linolenic acids. ROS production was dependent on the addition of β-NADH or NADPH to the medium. Diphenyleneiodonium inhibited the effect of oleic, linoleic and γ-linolenic acids on fibroblast superoxide release by 79%, 92% and 82%, respectively. Increased levels of p47phox phosphorylation due to fatty acid treatment were detected by Western blotting analyses of fibroblast proteins. Increased p47phox mRNA expression was observed using real-time PCR. The rank order for the fatty acid stimulation of the fibroblast oxidative burst was as follows: γ-linolenic > linoleic > oleic. In conclusion, oleic, linoleic and γ-linolenic acids stimulated ROS production via activation of the NADPH oxidase enzyme complex in fibroblasts. PMID:23579616

  3. The senescence-accelerated mouse prone-8 (SAM-P8) oxidative stress is associated with upregulation of renal NADPH oxidase system.

    PubMed

    Baltanás, Ana; Solesio, Maria E; Zalba, Guillermo; Galindo, María F; Fortuño, Ana; Jordán, Joaquín

    2013-12-01

    Herein, we investigate whether the NADPH oxidase might be playing a key role in the degree of oxidative stress in the senescence-accelerated mouse prone-8 (SAM-P8). To this end, the activity and expression of the NADPH oxidase, the ratio of glutathione and glutathione disulfides (GSH/GSSG), and the levels of malonyl dialdehyde (MDA) and nitrotyrosine (NT) were determined in renal tissue from SAM-P8 mice at the age of 1 and 6 months. The senescence-accelerated-resistant mouse (SAM-R1) was used as control. At the age of 1 month, NADPH oxidase activity and Nox2 protein expression were higher in SAM-P8 than in SAM-R1 mice. However, we found no differences in the GSH/GSSG ratio, MDA, NT, and Nox4 levels between both groups of animals. At the age of 6 months, SAM-R1 mice in comparison to SAM-P8 mice showed an increase in NADPH oxidase activity, which is associated with higher levels of NT and increased Nox4 and Nox2 expression levels. Furthermore, we found oxidative stress hallmarks including depletion in GSH/GSSG ratio and increase in MDA levels in the kidney of SAM-P8 mice. Finally, NADPH oxidase activity positively correlated with Nox2 expression in all the animals (r = 0.382, P < 0.05). Taken together, our data allow us to suggest that an increase in NADPH oxidase activity might be an early hallmark to predict future oxidative stress in renal tissue during the aging process that takes place in SAM-P8 mice.

  4. Regulation of the NADPH Oxidase RBOHD During Plant Immunity.

    PubMed

    Kadota, Yasuhiro; Shirasu, Ken; Zipfel, Cyril

    2015-08-01

    Pathogen recognition induces the production of reactive oxygen species (ROS) by NADPH oxidases in both plants and animals. ROS have direct antimicrobial properties, but also serve as signaling molecules to activate further immune outputs. However, ROS production has to be tightly controlled to avoid detrimental effects on host cells, but yet must be produced in the right amount, at the right place and at the right time upon pathogen perception. Plant NADPH oxidases belong to the respiratory burst oxidase homolog (RBOH) family, which contains 10 members in the model plant Arabidopsis thaliana. The perception of pathogen-associated molecular patterns (PAMPs) by pattern recognition receptors (PRRs) leads to a rapid, specific and strong production of ROS, which is dependent on RBOHD. RBOHD is mainly controlled by Ca(2+) via direct binding to EF-hand motifs and phosphorylation by Ca(2+)-dependent protein kinases. Recent studies have, however, revealed a critical role for a Ca(2+)-independent regulation of RBOHD. The plasma membrane-associated cytoplasmic kinase BIK1 (BOTRYTIS-INDUCED KINASE1), which is a direct substrate of the PRR complex, directly interacts with and phosphorylates RBOHD upon PAMP perception. Impairment of these phosphorylation events completely abolishes the function of RBOHD in immunity. These results suggest that RBOHD activity is tightly controlled by multilayered regulations. In this review, we summarize recent advances in our understanding of the regulatory mechanisms controlling RBOHD activation. © The Author 2015. Published by Oxford University Press on behalf of Japanese Society of Plant Physiologists. All rights reserved. For permissions, please email: journals.permissions@oup.com.

  5. NAD(P)H oxidase mediates the endothelial barrier dysfunction induced by TNF-alpha.

    PubMed

    Gertzberg, Nancy; Neumann, Paul; Rizzo, Victor; Johnson, Arnold

    2004-01-01

    We tested the hypothesis that the NAD(P)H oxidase-dependent generation of superoxide anion (O2-*) mediates tumor necrosis factor-alpha (TNF)-induced alterations in the permeability of pulmonary microvessel endothelial monolayers (PMEM). The permeability of PMEM was assessed by the clearance rate of Evans blue-labeled albumin. The NAD(P)H oxidase subcomponents p47phox and p22phox were assessed by immunofluorescent microscopy and Western blot. The reactive oxygen species O2-* was measured by the fluorescence of 6-carboxy-2',7'-dichlorodihydrofluorescein diacetatedi(acetoxymethyl ester), 5 (and 6)-chloromethyl-2',7'-dichlorodihydrofluorescein diacetate-acetyl ester, and dihydroethidium. TNF treatment (50 ng/ml for 4.0 h) induced 1) p47phox translocation, 2) an increase in p22phox protein, 3) increased localization of p47phox with p22phox, 4) O2-* generation, and 5) increased permeability to albumin. p22phox antisense oligonucleotide prevented the TNF-induced effect on p22phox, p47phox, O2-*, and permeability. The scrambled nonsense oligonucleotide had no effect. The TNF-induced increase in O2-* and permeability to albumin was also prevented by the O2-* scavenger Cu-Zn superoxide dismutase (100 U/ml). The results indicate that the activation of NAD(P)H oxidase, via the generation of O2-*, mediates TNF-induced barrier dysfunction in PMEM.

  6. Priming of the neutrophil NADPH oxidase activation: role of p47phox phosphorylation and NOX2 mobilization to the plasma membrane.

    PubMed

    El-Benna, Jamel; Dang, Pham My-Chan; Gougerot-Pocidalo, Marie-Anne

    2008-07-01

    Neutrophils play an essential role in host defense against microbial pathogens and in the inflammatory reaction. Upon activation, neutrophils produce superoxide anion (O*2), which generates other reactive oxygen species (ROS) such as hydrogen peroxide (H2O2), hydroxyl radical (OH*) and hypochlorous acid (HOCl), together with microbicidal peptides and proteases. The enzyme responsible for O2* production is called the nicotinamide adenine dinucleotide phosphate (NADPH) oxidase or respiratory burst oxidase. This multicomponent enzyme system is composed of two trans-membrane proteins (p22phox and gp91phox/NOX2, which form the cytochrome b558), three cytosolic proteins (p47phox, p67phox, p40phox) and a GTPase (Rac1 or Rac2), which assemble at membrane sites upon cell activation. NADPH oxidase activation in phagocytes can be induced by a large number of soluble and particulate factors. Three major events accompany NAPDH oxidase activation: (1) protein phosphorylation, (2) GTPase activation, and (3) translocation of cytosolic components to the plasma membrane to form the active enzyme. Actually, the neutrophil NADPH oxidase exists in different states: resting, primed, activated, or inactivated. The resting state is found in circulating blood neutrophils. The primed state can be induced by neutrophil adhesion, pro-inflammatory cytokines, lipopolysaccharide, and other agents and has been characterized as a "ready to go" state, which results in a faster and higher response upon exposure to a second stimulus. The active state is found at the inflammatory or infection site. Activation is induced by the pathogen itself or by pathogen-derived formylated peptides and other agents. Finally, inactivation of NADPH oxidase is induced by anti-inflammatory agents to limit inflammation. Priming is a "double-edged sword" process as it contributes to a rapid and efficient elimination of the pathogens but can also induce the generation of large quantities of toxic ROS by hyperactivation of

  7. Pigment epithelium-derived factor stimulates skeletal muscle glycolytic activity through NADPH oxidase-dependent reactive oxygen species production.

    PubMed

    Carnagarin, Revathy; Carlessi, Rodrigo; Newsholme, Philip; Dharmarajan, Arun M; Dass, Crispin R

    2016-09-01

    Pigment epithelium-derived factor is a multifunctional serpin implicated in insulin resistance in metabolic disorders. Recent evidence suggests that exposure of peripheral tissues such as skeletal muscle to PEDF has profound metabolic consequences with predisposition towards chronic conditions such as obesity, type 2 diabetes, metabolic syndrome and polycystic ovarian syndrome. Chronic inflammation shifts muscle metabolism towards increased glycolysis and decreased oxidative metabolism. In the present study, we demonstrate a novel effect of PEDF on cellular metabolism in mouse cell line (C2C12) and human primary skeletal muscle cells. PEDF addition to skeletal muscle cells induced enhanced phospholipase A2 activity. This was accompanied with increased production of reactive oxygen species in a nicotinamide adenine dinucleotide phosphate (NADPH) oxidase-dependent manner that triggered a shift towards a more glycolytic phenotype. Extracellular flux analysis and glucose consumption assays demonstrated that PEDF treatment resulted in enhanced glycolysis but did not change mitochondrial respiration. Our results demonstrate that skeletal muscle cells express a PEDF-inducible oxidant generating system that enhances glycolysis but is sensitive to antioxidants and NADPH oxidase inhibition. Copyright © 2016 Elsevier Ltd. All rights reserved.

  8. The NADPH oxidase inhibitor apocynin induces nitric oxide synthesis via oxidative stress

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

    Riganti, Chiara; Costamagna, Costanzo; Doublier, Sophie

    We have recently shown that apocynin elicits an oxidative stress in N11 mouse glial cells and other cell types. Here we report that apocynin increased the accumulation of nitrite, the stable derivative of nitric oxide (NO), in the extracellular medium of N11 cell cultures, and the NO synthase (NOS) activity in cell lysates. The increased synthesis of NO was associated with increased expression of inducible NOS (iNOS) mRNA, increased nuclear translocation of the redox-sensitive transcription factor NF-{kappa}B and decreased intracellular level of its inhibitor IkB{alpha}. These effects, accompanied by increased production of H{sub 2}O{sub 2}, were very similar to thosemore » observed after incubation with bacterial lipopolysaccharide (LPS) and were inhibited by catalase. These results suggest that apocynin, similarly to LPS, induces increased NO synthesis by eliciting a generation of reactive oxygen species (ROS), which in turn causes NF-{kappa}B activation and increased expression of iNOS. Therefore, the increased bioavailability of NO reported in the literature after in vivo or in vitro treatments with apocynin might depend, at least partly, on the drug-elicited induction of iNOS, and not only on the inhibition of NADPH oxidase and the subsequent decreased scavenging of NO by oxidase-derived ROS, as it is often supposed.« less

  9. NADPH Oxidase-Mediated ROS Production Determines Insulin's Action on the Retinal Microvasculature.

    PubMed

    Kida, Teruyo; Oku, Hidehiro; Horie, Taeko; Matsuo, Junko; Kobayashi, Takatoshi; Fukumoto, Masanori; Ikeda, Tsunehiko

    2015-10-01

    To determine whether insulin induces nitric oxide (NO) formation in retinal microvessels and to examine the effects of high glucose on the formation of NO. Freshly isolated rat retinal microvessels were incubated in normal (5.5 mM) or high (20 mM) glucose with or without insulin (100 nM). The levels of insulin-induced NO and reactive oxygen species (ROS) in the retinal microvessels were determined semiquantitatively using fluorescent probes, 4,5-diaminofluorescein diacetate, and hydroethidine, respectively, and a laser scanning confocal microscope. The insulin-induced changes of NO in rat retinal endothelial cells and pericytes cultured at different glucose concentrations (5.5 and 25 mM) were determined using flow cytometry. Nitric oxide synthase (NOS) protein levels were determined by Western blot analysis; intracellular levels of ROS were determined using fluorescence-activated cell sorting (FACS) analysis of ethidium fluorescence; and nicotinamide adenine dinucleotide phosphate (NADPH) oxidase RNA expression was quantified using real-time PCR. Exposure of microvessels to insulin under normal glucose conditions led to a significant increase in NO levels; however, this increase was significantly suppressed when the microvessels were incubated under high glucose conditions. Intracellular levels of ROS were significantly increased in both retinal microvessels and cultured microvascular cells under high glucose conditions. The expression of NOS and NADPH oxidase were significantly increased in endothelial cells and pericytes under high glucose conditions. The increased formation of NO by insulin and its suppression by high glucose conditions suggests that ROS production mediated by NADPH oxidase is important by insulin's effect on the retinal microvasculature.

  10. NADPH oxidase 4 limits bone mass by promoting osteoclastogenesis

    PubMed Central

    Goettsch, Claudia; Babelova, Andrea; Trummer, Olivia; Erben, Reinhold G.; Rauner, Martina; Rammelt, Stefan; Weissmann, Norbert; Weinberger, Valeska; Benkhoff, Sebastian; Kampschulte, Marian; Obermayer-Pietsch, Barbara; Hofbauer, Lorenz C.; Brandes, Ralf P.; Schröder, Katrin

    2013-01-01

    ROS are implicated in bone diseases. NADPH oxidase 4 (NOX4), a constitutively active enzymatic source of ROS, may contribute to the development of such disorders. Therefore, we studied the role of NOX4 in bone homeostasis. Nox4–/– mice displayed higher bone density and reduced numbers and markers of osteoclasts. Ex vivo, differentiation of monocytes into osteoclasts with RANKL and M-CSF induced Nox4 expression. Loss of NOX4 activity attenuated osteoclastogenesis, which was accompanied by impaired activation of RANKL-induced NFATc1 and c-JUN. In an in vivo model of murine ovariectomy–induced osteoporosis, pharmacological inhibition or acute genetic knockdown of Nox4 mitigated loss of trabecular bone. Human bone obtained from patients with increased osteoclast activity exhibited increased NOX4 expression. Moreover, a SNP of NOX4 was associated with elevated circulating markers of bone turnover and reduced bone density in women. Thus, NOX4 is involved in bone loss and represents a potential therapeutic target for the treatment of osteoporosis. PMID:24216508

  11. Ursolic acid suppresses TGF-β1-induced quiescent HSC activation and transformation by inhibiting NADPH oxidase expression and Hedgehog signaling

    PubMed Central

    Yu, Shan-Shan; Chen, Biao; Huang, Chen-Kai; Zhou, Juan-Juan; Huang, Xin; Wang, An-Jiang; Li, Bi-Min; He, Wen-Hua; Zhu, Xuan

    2017-01-01

    Activation of quiescent hepatic stellate cells (q-HSCs) and their transformation to myofibroblasts (MFBs) is a key event in liver fibrosis. Hedgehog (Hh) signaling stimulates q-HSCs to differentiate into MFBs, and NADPH oxidase (NOX) may be involved in regulating Hh signaling. The author's preliminary study demonstrated that ursolic acid (UA) selectively induces apoptosis in activated HSCs and inhibits their proliferation in vitro via negative regulation of NOX activity and expression. However, the effect of UA on q-HSCs remains to be elucidated. The present study aimed to investigate the effect of UA on q-HSC activation and HSC transformation and to observe alterations in the NOX and Hh signaling pathways during q-HSC activation. q-HSC were isolated from adult male Sprague-Dawley rats. Following culture for 3 days, the cells were treated with or without transforming growth factor-β1 (TGF-β1; 5 µg/l); intervention groups were pretreated with UA (40 µM) or diphenyleneiodonium chloride (DPI; 10 µM) for 30 min prior to addition of TGF-β1. mRNA and protein expression of NOX and Hh signaling components and markers of q-HSC activation were examined by western blotting and reverse transcription-polymerase chain reaction. TGF-β1 induced activation of q-HSCs, with increased expression of α-smooth muscle actin (α-SMA) and type I collagen. In addition, expression of NOX subunits (gp91phox, p67phox, p22phox, and Rac1) and Hh signaling components, including sonic Hh, sterol-4-alpha-methyl oxidase, and Gli family zinc finger 2, were upregulated in activated HSCs. Pretreatment of q-HSCs with UA or DPI prior to TGF-β1 significantly downregulated expression of NOX subunits and Hh signaling components and additionally inhibited expression of α-SMA and type I collagen, thereby preventing transformation to MFBs. UA inhibited TGF-β1-induced activation of q-HSCs and their transformation by inhibiting expression of NOX subunits and the downstream Hh pathway. PMID:29042951

  12. Elevated Mitochondrial Reactive Oxygen Species and Cellular Redox Imbalance in Human NADPH-Oxidase-Deficient Phagocytes

    PubMed Central

    Sundqvist, Martina; Christenson, Karin; Björnsdottir, Halla; Osla, Veronica; Karlsson, Anna; Dahlgren, Claes; Speert, David P.; Fasth, Anders; Brown, Kelly L.; Bylund, Johan

    2017-01-01

    Chronic granulomatous disease (CGD) is caused by mutations in genes that encode the NADPH-oxidase and result in a failure of phagocytic cells to produce reactive oxygen species (ROS) via this enzyme system. Patients with CGD are highly susceptible to infections and often suffer from inflammatory disorders; the latter occurs in the absence of infection and correlates with the spontaneous production of inflammatory cytokines. This clinical feature suggests that NADPH-oxidase-derived ROS are not required for, or may even suppress, inflammatory processes. Experimental evidence, however, implies that ROS are in fact required for inflammatory cytokine production. By using a myeloid cell line devoid of a functional NADPH-oxidase and primary CGD cells, we analyzed intracellular oxidants, signs of oxidative stress, and inflammatory cytokine production. Herein, we demonstrate that phagocytes lacking a functional NADPH-oxidase, namely primary CGD phagocytes and a gp91phox-deficient cell line, display elevated levels of ROS derived from mitochondria. Accordingly, these cells, despite lacking the major source of cellular ROS, display clear signs of oxidative stress, including an induced expression of antioxidants and altered oxidation of cell surface thiols. These observed changes in redox state were not due to abnormalities in mitochondrial mass or membrane integrity. Finally, we demonstrate that increased mitochondrial ROS enhanced phosphorylation of ERK1/2, and induced production of IL8, findings that correlate with previous observations of increased MAPK activation and inflammatory cytokine production in CGD cells. Our data show that elevated baseline levels of mitochondria-derived oxidants lead to the counter-intuitive observation that CGD phagocytes are under oxidative stress and have enhanced MAPK signaling, which may contribute to the elevated basal production of inflammatory cytokines and the sterile inflammatory manifestations in CGD. PMID:29375548

  13. ERK1/2 pathway is involved in renal gluconeogenesis inhibition under conditions of lowered NADPH oxidase activity.

    PubMed

    Winiarska, Katarzyna; Jarzyna, Robert; Dzik, Jolanta M; Jagielski, Adam K; Grabowski, Michal; Nowosielska, Agata; Focht, Dorota; Sierakowski, Bartosz

    2015-04-01

    The aim of this study was to elucidate the mechanisms involved in the inhibition of renal gluconeogenesis occurring under conditions of lowered activity of NADPH oxidase (Nox), the enzyme considered to be one of the main sources of reactive oxygen species in kidneys. The in vitro experiments were performed on primary cultures of rat renal proximal tubules, with the use of apocynin, a selective Nox inhibitor, and TEMPOL (4-hydroxy-2,2,6,6-tetramethylpiperidine-1-oxyl), a potent superoxide radical scavenger. In the in vivo experiments, Zucker diabetic fatty (ZDF) rats, a well established model of diabetes type 2, were treated with apocynin solution in drinking water. The main in vitro findings are the following: (1) both apocynin and TEMPOL attenuate the rate of gluconeogenesis, inhibiting the step catalyzed by phosphoenolpyruvate carboxykinase (PEPCK), a key enzyme of the process; (2) in the presence of the above-noted compounds the expression of PEPCK and the phosphorylation of transcription factor CREB and ERK1/2 kinases are lowered; (3) both U0126 (MEK inhibitor) and 3-(2-aminoethyl)-5-((4-ethoxyphenyl)methylene)-2,4-thiazolidinedione (ERK inhibitor) diminish the rate of glucose synthesis via mechanisms similar to those of apocynin and TEMPOL. The observed apocynin in vivo effects include: (1) slight attenuation of hyperglycemia; (2) inhibition of renal gluconeogenesis; (3) a decrease in renal PEPCK activity and content. In view of the results summarized above, it can be concluded that: (1) the lowered activity of the ERK1/2 pathway is of importance for the inhibition of renal gluconeogenesis found under conditions of lowered superoxide radical production by Nox; (2) the mechanism of this phenomenon includes decreased PEPCK expression, resulting from diminished activity of transcription factor CREB; (3) apocynin-evoked inhibition of renal gluconeogenesis contributes to the hypoglycemic action of this compound observed in diabetic animals. Thus, the study has

  14. Role of the Rho GTPase Rac in the activation of the phagocyte NADPH oxidase

    PubMed Central

    Pick, Edgar

    2014-01-01

    The superoxide-generating NADPH oxidase of phagocytes consists of the membrane-associated cytochrome b558 (a heterodimer of Nox2 and p22phox) and 4 cytosolic components: p47phox, p67phox, p40phox, and the small GTPase, Rac, in complex with RhoGDI. Superoxide is produced by the NADPH-driven reduction of molecular oxygen, via a redox gradient located in Nox2. Electron flow in Nox2 is initiated by interaction with cytosolic components, which translocate to the membrane, p67phox playing the central role. The participation of Rac is expressed in the following sequence: (1) Translocation of the RacGDP-RhoGDI complex to the membrane; (2) Dissociation of RacGDP from RhoGDI; (3) GDP to GTP exchange on Rac, mediated by a guanine nucleotide exchange factor; (4) Binding of RacGTP to p67phox; (5) Induction of a conformational change in p67phox, promoting interaction with Nox2. The particular involvement of Rac in NADPH oxidase assembly serves as a paradigm for signaling by Rho GTPases, in general. PMID:24598074

  15. NADPH Oxidase Contributes to Resistance against Aggregatibacter actinomycetemcomitans-Induced Periodontitis in Mice.

    PubMed

    Bast, Antje; Kubis, Helen; Holtfreter, Birte; Ribback, Silvia; Martin, Heiner; Schreiner, Helen C; Dominik, Malte J; Breitbach, Katrin; Dombrowski, Frank; Kocher, Thomas; Steinmetz, Ivo

    2017-02-01

    Aggregatibacter actinomycetemcomitans is a Gram-negative commensal bacterium of the oral cavity which has been associated with the pathogenesis of periodontitis with severe alveolar bone destruction. The role of host factors such as reactive oxygen and nitrogen intermediates in periodontal A. actinomycetemcomitans infection and progression to periodontitis is still ill-defined. Therefore, this study aimed to analyze the role of NADPH oxidase and inducible nitric oxide synthase (iNOS) in a murine model of A. actinomycetemcomitans-induced periodontitis. NADPH oxidase-deficient (gp91 phox knockout [KO]), iNOS-deficient (iNOS KO), and C57BL/6 wild-type mice were orally infected with A. actinomycetemcomitans and analyzed for bacterial colonization at various time points. Alveolar bone mineral density and alveolar bone volume were quantified by three-dimensional micro-computed tomography, and the degree of tissue inflammation was calculated by histological analyses. At 5 weeks after infection, A. actinomycetemcomitans persisted at significantly higher levels in the murine oral cavities of infected gp91 phox KO mice than in those of iNOS KO and C57BL/6 mice. Concomitantly, alveolar bone mineral density was significantly lower in all three infected groups than in uninfected controls, but with the highest loss of bone density in infected gp91 phox KO mice. Only infected gp91 phox KO mice revealed significant loss of alveolar bone volume and enhanced inflammatory cell infiltration, as well as an increased number of osteoclasts. Our results indicate that NADPH oxidase is important to control A. actinomycetemcomitans infection in the murine oral cavity and to prevent subsequent alveolar bone destruction and osteoclastogenesis. Copyright © 2017 American Society for Microbiology.

  16. NADPH Oxidase Contributes to Resistance against Aggregatibacter actinomycetemcomitans-Induced Periodontitis in Mice

    PubMed Central

    Bast, Antje; Kubis, Helen; Holtfreter, Birte; Ribback, Silvia; Martin, Heiner; Schreiner, Helen C.; Dominik, Malte J.; Breitbach, Katrin; Dombrowski, Frank; Kocher, Thomas

    2016-01-01

    ABSTRACT Aggregatibacter actinomycetemcomitans is a Gram-negative commensal bacterium of the oral cavity which has been associated with the pathogenesis of periodontitis with severe alveolar bone destruction. The role of host factors such as reactive oxygen and nitrogen intermediates in periodontal A. actinomycetemcomitans infection and progression to periodontitis is still ill-defined. Therefore, this study aimed to analyze the role of NADPH oxidase and inducible nitric oxide synthase (iNOS) in a murine model of A. actinomycetemcomitans-induced periodontitis. NADPH oxidase-deficient (gp91phox knockout [KO]), iNOS-deficient (iNOS KO), and C57BL/6 wild-type mice were orally infected with A. actinomycetemcomitans and analyzed for bacterial colonization at various time points. Alveolar bone mineral density and alveolar bone volume were quantified by three-dimensional micro-computed tomography, and the degree of tissue inflammation was calculated by histological analyses. At 5 weeks after infection, A. actinomycetemcomitans persisted at significantly higher levels in the murine oral cavities of infected gp91phox KO mice than in those of iNOS KO and C57BL/6 mice. Concomitantly, alveolar bone mineral density was significantly lower in all three infected groups than in uninfected controls, but with the highest loss of bone density in infected gp91phox KO mice. Only infected gp91phox KO mice revealed significant loss of alveolar bone volume and enhanced inflammatory cell infiltration, as well as an increased number of osteoclasts. Our results indicate that NADPH oxidase is important to control A. actinomycetemcomitans infection in the murine oral cavity and to prevent subsequent alveolar bone destruction and osteoclastogenesis. PMID:27849181

  17. Heterodimerization controls localization of Duox-DuoxA NADPH oxidases in airway cells.

    PubMed

    Luxen, Sylvia; Noack, Deborah; Frausto, Monika; Davanture, Suzel; Torbett, Bruce E; Knaus, Ulla G

    2009-04-15

    Duox NADPH oxidases generate hydrogen peroxide at the air-liquid interface of the respiratory tract and at apical membranes of thyroid follicular cells. Inactivating mutations of Duox2 have been linked to congenital hypothyroidism, and epigenetic silencing of Duox is frequently observed in lung cancer. To study Duox regulation by maturation factors in detail, its association with these factors, differential use of subunits and localization was analyzed in a lung cancer cell line and undifferentiated or polarized lung epithelial cells. We show here that Duox proteins form functional heterodimers with their respective DuoxA subunits, in close analogy to the phagocyte NADPH oxidase. Characterization of novel DuoxA1 isoforms and mispaired Duox-DuoxA complexes revealed that heterodimerization is a prerequisite for reactive oxygen species production. Functional Duox1 and Duox2 localize to the leading edge of migrating cells, augmenting motility and wound healing. DuoxA subunits are responsible for targeting functional oxidases to distinct cellular compartments in lung epithelial cells, including Duox2 expression in ciliated cells in an ex vivo differentiated lung epithelium. As these locations probably define signaling specificity of Duox1 versus Duox2, these findings will facilitate monitoring Duox isoform expression in lung disease, a first step for early screening procedures and rational drug development.

  18. Trimethyltin-Induced Microglial Activation via NADPH Oxidase and MAPKs Pathway in BV-2 Microglial Cells.

    PubMed

    Kim, Da Jung; Kim, Yong Sik

    2015-01-01

    Trimethyltin (TMT) is known as a potent neurotoxicant that causes neuronal cell death and neuroinflammation, particularly in the hippocampus. Microglial activation is one of the prominent pathological features of TMT neurotoxicity. Nevertheless, it remains unclear how microglial activation occurs in TMT intoxication. In this study, we aimed to investigate the signaling pathways in TMT-induced microglial activation using BV-2 murine microglial cells. Our results revealed that TMT generates reactive oxygen species (ROS) and increases the expression of CD11b and nuclear factor-κB- (NF-κB-) mediated nitric oxide (NO) and tumor necrosis factor- (TNF-) α in BV-2 cells. We also observed that NF-κB activation was controlled by p38 and JNK phosphorylation. Moreover, TMT-induced ROS generation occurred via nicotinamide adenine dinucleotide phosphate (NADPH) oxidase in BV-2 cells. Interestingly, treatment with the NADPH oxidase inhibitor apocynin significantly suppressed p38 and JNK phosphorylation and NF-κB activation and ultimately the production of proinflammatory mediators upon TMT exposure. These findings indicate that NADPH oxidase-dependent ROS generation activated p38 and JNK mitogen-activated protein kinases (MAPKs), which then stimulated NF-κB to release proinflammatory mediators in the TMT-treated BV-2 cells.

  19. Trimethyltin-Induced Microglial Activation via NADPH Oxidase and MAPKs Pathway in BV-2 Microglial Cells

    PubMed Central

    Kim, Da Jung; Kim, Yong Sik

    2015-01-01

    Trimethyltin (TMT) is known as a potent neurotoxicant that causes neuronal cell death and neuroinflammation, particularly in the hippocampus. Microglial activation is one of the prominent pathological features of TMT neurotoxicity. Nevertheless, it remains unclear how microglial activation occurs in TMT intoxication. In this study, we aimed to investigate the signaling pathways in TMT-induced microglial activation using BV-2 murine microglial cells. Our results revealed that TMT generates reactive oxygen species (ROS) and increases the expression of CD11b and nuclear factor-κB- (NF-κB-) mediated nitric oxide (NO) and tumor necrosis factor- (TNF-) α in BV-2 cells. We also observed that NF-κB activation was controlled by p38 and JNK phosphorylation. Moreover, TMT-induced ROS generation occurred via nicotinamide adenine dinucleotide phosphate (NADPH) oxidase in BV-2 cells. Interestingly, treatment with the NADPH oxidase inhibitor apocynin significantly suppressed p38 and JNK phosphorylation and NF-κB activation and ultimately the production of proinflammatory mediators upon TMT exposure. These findings indicate that NADPH oxidase-dependent ROS generation activated p38 and JNK mitogen-activated protein kinases (MAPKs), which then stimulated NF-κB to release proinflammatory mediators in the TMT-treated BV-2 cells. PMID:26221064

  20. trans-Chalcone, a flavonoid precursor, inhibits UV-induced skin inflammation and oxidative stress in mice by targeting NADPH oxidase and cytokine production.

    PubMed

    Martinez, Renata M; Pinho-Ribeiro, Felipe A; Steffen, Vinicius S; Caviglione, Carla V; Fattori, Victor; Bussmann, Allan J C; Bottura, Carolina; Fonseca, Maria J V; Vignoli, Josiane A; Baracat, Marcela M; Georgetti, Sandra R; Verri, Waldiceu A; Casagrande, Rubia

    2017-07-01

    trans-Chalcone is a plant flavonoid precursor, which lacks broad investigation on its biological activity in inflammatory processes. In the present study, anti-inflammatory and antioxidant mechanisms of systemic administration with trans-chalcone, a flavonoid precursor, on ultraviolet (UV) irradiation-induced skin inflammation and oxidative stress in hairless mice were investigated by the following parameters: skin edema, myeloperoxidase activity (neutrophil marker), matrix metalloproteinase-9 activity, reduced glutathione levels, catalase activity, lipid peroxidation products, superoxide anion production, gp 91phox (NADPH oxidase subunit) mRNA expression by quantitative PCR and cytokine production by ELISA. Systemic treatment with trans-chalcone inhibited skin inflammation by reducing skin edema and neutrophil recruitment, and also inhibited matrix metalloproteinase-9 activity. trans-Chalcone also inhibited oxidative stress, gp 91phox mRNA expression, and the production of a wide range of pro-inflammatory cytokines, while it did not affect anti-inflammatory cytokines induced by UV irradiation. However, trans-chalcone did not prevent oxidative stress in vitro, suggesting that its in vivo effect is more related to anti-inflammatory properties rather than a direct antioxidant effect. In conclusion, treatment with trans-chalcone inhibited UV-induced skin inflammation resulting in oxidative stress inhibition in vivo. Therefore, systemic supplementation with this compound may represent an important therapeutic approach in inflammatory skin diseases induced by UV irradiation.

  1. The NADPH oxidase Cpnox1 is required for full pathogenicity of the ergot fungus Claviceps purpurea.

    PubMed

    Giesbert, Sabine; Schürg, Timo; Scheele, Sandra; Tudzynski, Paul

    2008-05-01

    The role of reactive oxygen species (ROS) in interactions between phytopathogenic fungi and their hosts is well established. An oxidative burst mainly caused by superoxide formation by membrane-associated NADPH oxidases is an essential element of plant defence reactions. Apart from primary effects, ROS play a major role as a second messenger in host response. Recently, NADPH oxidase (nox)-encoding genes have been identified in filamentous fungi. Functional analyses have shown that these fungal enzymes are involved in sexual differentiation, and there is growing evidence that they also affect developmental programmes involved in fungus-plant interactions. Here we show that in the biotrophic plant pathogen Claviceps purpurea deletion of the cpnox1 gene, probably encoding an NADPH oxidase, has impact on germination of conidia and pathogenicity: Deltacpnox1 mutants can penetrate the host epidermis, but they are impaired in colonization of the plant ovarian tissue. In the few cases where macroscopic signs of infection (honeydew) appear, they are extremely delayed and fully developed sclerotia have never been observed. C. purpurea Nox1 is important for the interaction with its host, probably by directly affecting pathogenic differentiation of the fungus.

  2. Metformin and liraglutide ameliorate high glucose-induced oxidative stress via inhibition of PKC-NAD(P)H oxidase pathway in human aortic endothelial cells.

    PubMed

    Batchuluun, Battsetseg; Inoguchi, Toyoshi; Sonoda, Noriyuki; Sasaki, Shuji; Inoue, Tomoaki; Fujimura, Yoshinori; Miura, Daisuke; Takayanagi, Ryoichi

    2014-01-01

    Metformin and glucagon like peptide-1 (GLP-1) prevent diabetic cardiovascular complications and atherosclerosis. However, the direct effects on hyperglycemia-induced oxidative stress in endothelial cells are not fully understood. Thus, we aimed to evaluate the effects of metformin and a GLP-1 analog, liraglutide on high glucose-induced oxidative stress. Production of reactive oxygen species (ROS), activation of protein kinase C (PKC) and NAD(P)H oxidase, and changes in signaling molecules in response to high glucose exposure were evaluated in human aortic endothelial cells with and without treatment of metformin and liraglutide, alone or in combination. PKC-NAD(P)H oxidase pathway was assessed by translocation of GFP-fused PKCβ2 isoform and GFP-fused p47phox, a regulatory subunit of NAD(P)H oxidase, in addition to endogenous PKC phosphorylation and NAD(P)H oxidase activity. High glucose-induced ROS overproduction was blunted by metformin or liraglutide treatment, with a further decrease by a combination of these drugs. Exposure to high glucose caused PKCβ2 translocation and a time-dependent phosphorylation of endogenous PKC but failed to induce its translocation and phosphorylation in the cells treated with metformin and liraglutide. Furthermore, both drugs inhibited p47phox translocation and NAD(P)H oxidase activation, and prevented the high glucose-induced changes in intracellulalr diacylglycerol (DAG) level and phosphorylation of AMP-activated protein kinase (AMPK). A combination of these drugs further enhanced all of these effects. Metformin and liraglutide ameliorate high glucose-induced oxidative stress by inhibiting PKC-NAD(P)H oxidase pathway. A combination of these two drugs provides augmented protective effects, suggesting the clinical usefulness in prevention of diabetic vascular complications. Copyright © 2013 Elsevier Ireland Ltd. All rights reserved.

  3. Lycopene Inhibits Metastasis of Human Liver Adenocarcinoma SK-Hep-1 Cells by Downregulation of NADPH Oxidase 4 Protein Expression.

    PubMed

    Jhou, Bo-Yi; Song, Tuzz-Ying; Lee, Inn; Hu, Miao-Lin; Yang, Nae-Cherng

    2017-08-16

    NADPH oxidase 4 (NOX4), with the sole function to produce reactive oxygen species (ROS), can be a molecular target for disrupting cancer metastasis. Several studies have indicated that lycopene exhibited anti-metastatic actions in vitro and in vivo. However, the role of NOX4 in the anti-metastatic action of lycopene remains unknown. Herein, we first confirmed the anti-metastatic effect of lycopene (0.1-5 μM) on human liver adenocarcinoma SK-Hep-1 cells. We showed that lycopene significantly inhibited NOX4 protein expression, with the strongest inhibition of 64.3 ± 10.2% (P < 0.05) at 2.5 μM lycopene. Lycopene also significantly inhibited NOX4 mRNA expression, NOX activity, and intracellular ROS levels in SK-Hep-1 cells. We then determined the effects of lycopene on transforming growth factor β (TGF-β)-induced metastasis. We found that TGF-β (5 ng/mL) significantly increased migration, invasion, and adhesion activity, the intracellular ROS level, matrix metalloproteinase 9 (MMP-9) and MMP-2 activities, the level of NOX4 protein expression, and NOX activity. All these TGF-β-induced effects were antagonized by the incubation of SK-Hep-1 cells with lycopene (2.5 μM). Using transient transfection of siRNA against NOX4, we found that the downregulation of NOX4 could mimic lycopene by inhibiting cell migration and the activities of MMP-9 and MMP-2 during the incubation with or without TGF-β on SK-Hep-1 cells. The results demonstrate that the downregulation of NOX4 plays a crucial role in the anti-metastatic action of lycopene in SK-Hep-1 cells.

  4. Characterization of potent and selective iodonium-class inhibitors of NADPH oxidases.

    PubMed

    Lu, Jiamo; Risbood, Prabhakar; Kane, Charles T; Hossain, Md Tafazzal; Anderson, Larry; Hill, Kimberly; Monks, Anne; Wu, Yongzhong; Antony, Smitha; Juhasz, Agnes; Liu, Han; Jiang, Guojian; Harris, Erik; Roy, Krishnendu; Meitzler, Jennifer L; Konaté, Mariam; Doroshow, James H

    2017-11-01

    The NADPH oxidases (NOXs) play a recognized role in the development and progression of inflammation-associated disorders, as well as cancer. To date, several NOX inhibitors have been developed, through either high throughput screening or targeted disruption of NOX interaction partners, although only a few have reached clinical trials. To improve the efficacy and bioavailability of the iodonium class NOX inhibitor diphenylene iodonium (DPI), we synthesized 36 analogs of DPI, focusing on improved solubility and functionalization. The inhibitory activity of the analogs was interrogated through cell viability and clonogenic studies with a colon cancer cell line (HT-29) that depends on NOX for its proliferative potential. Lack of altered cellular respiration at relevant iodonium analog concentrations was also demonstrated. Additionally, inhibition of ROS generation was evaluated with a luminescence assay for superoxide, or by Amplex Red® assay for H 2 O 2 production, in cell models expressing specific NOX isoforms. DPI and four analogs (NSCs 740104, 751140, 734428, 737392) strongly inhibited HT-29 cell growth and ROS production with nanomolar potency in a concentration-dependent manner. NSC 737392 and 734428, which both feature nitro functional groups at the meta position, had >10-fold higher activity against ROS production by cells that overexpress dual oxidase 2 (DUOX2) than the other compounds examined (IC 50 ≈200-400nM). Based on these results, we synthesized and tested NSC 780521 with optimized potency against DUOX2. Iodonium analogs with anticancer activity, including the first generation of targeted agents with improved specificity against DUOX2, may provide a novel therapeutic approach to NOX-driven tumors. Published by Elsevier Inc.

  5. Khz-cp (crude polysaccharide extract obtained from the fusion of Ganoderma lucidum and Polyporus umbellatus mycelia) induces apoptosis by increasing intracellular calcium levels and activating P38 and NADPH oxidase-dependent generation of reactive oxygen species in SNU-1 cells.

    PubMed

    Kim, Tae Hwan; Kim, Ju Sung; Kim, Zoo Haye; Huang, Ren Bin; Chae, Young Lye; Wang, Ren Sheng

    2014-07-10

    Khz-cp is a crude polysaccharide extract that is obtained after nuclear fusion in Ganoderma lucidum and Polyporus umbellatus mycelia (Khz). It inhibits the growth of cancer cells. Khz-cp was extracted by solvent extraction. The anti-proliferative activity of Khz-cp was confirmed by using Annexin-V/PI-flow cytometry analysis. Intracellular calcium increase and measurement of intracellular reactive oxygen species (ROS) were performed by using flow cytometry and inverted microscope. SNU-1 cells were treated with p38, Bcl-2 and Nox family siRNA. siRNA transfected cells was employed to investigate the expression of apoptotic, growth and survival genes in SNU-1 cells. Western blot analysis was performed to confirm the expression of the genes. In the present study, Khz-cp induced apoptosis preferentially in transformed cells and had only minimal effects on non-transformed cells. Furthermore, Khz-cp was found to induce apoptosis by increasing the intracellular Ca2+ concentration ([Ca2+]i) and activating P38 to generate reactive oxygen species (ROS) via NADPH oxidase and the mitochondria. Khz-cp-induced apoptosis was caspase dependent and occurred via a mitochondrial pathway. ROS generation by NADPH oxidase was critical for Khz-cp-induced apoptosis, and although mitochondrial ROS production was also required, it appeared to occur secondary to ROS generation by NADPH oxidase. Activation of NADPH oxidase was shown by the translocation of the regulatory subunits p47phox and p67phox to the cell membrane and was necessary for ROS generation by Khz-cp. Khz-cp triggered a rapid and sustained increase in [Ca2+]i that activated P38. P38 was considered to play a key role in the activation of NADPH oxidase because inhibition of its expression or activity abrogated membrane translocation of the p47phox and p67phox subunits and ROS generation. In summary, these data indicate that Khz-cp preferentially induces apoptosis in cancer cells and that the signaling mechanisms involve an

  6. NADPH oxidase and redox status in amygdala, hippocampus and cortex of male Wistar rats in an animal model of post-traumatic stress disorder.

    PubMed

    Petrovic, Romana; Puskas, Laslo; Jevtic Dozudic, Gordana; Stojkovic, Tihomir; Velimirovic, Milica; Nikolic, Tatjana; Zivkovic, Milica; Djorovic, Djordje J; Nenadovic, Milutin; Petronijevic, Natasa

    2018-05-26

    Post-traumatic stress disorder (PTSD) is a highly prevalent and impairing disorder. Oxidative stress is implicated in its pathogenesis. Nicotinamide adenine dinucleotide phosphate (NADPH) oxidase is an important source of free radicals. The aim of the study was to assess oxidative stress parameters, activities of respiratory chain enzymes, and the expression of NADPH oxidase subunits (gp91phox, p22phox, and p67phox) in the single prolonged stress (SPS) animal model of PTSD. Twenty-four (12 controls; 12 subjected to SPS), 9-week-old, male Wistar rats were used. SPS included physical restraint, forced swimming, and ether exposure. The rats were euthanized seven days later. Cortex, hippocampus, amygdala, and thalamus were dissected. Malondialdehyde (MDA), reduced glutathione (GSH), superoxide dismutase (SOD), glutathione peroxidase (GPx), catalase (CAT), Complex I, and cytochrome C oxidase were measured using spectrophotometric methods, while the expression of NADPH oxidase subunits was determined by Western blot. Increased MDA and decreased GSH concentrations were found in the amygdala and hippocampus of the SPS rats. SOD activity was decreased in amygdala and GPx was decreased in hippocampus. Increased expression of the NADPH oxidase subunits was seen in amygdala, while mitochondrial respiratory chain enzyme expression was unchanged both in amygdala and hippocampus. In the cortex concentrations of MDA and GSH were unchanged despite increased Complex I and decreased GPx, while in the thalamus no change of any parameter was noticed. We conclude that oxidative stress is present in hippocampus and amygdala seven days after the SPS procedure. NADPH oxidase seems to be a main source of free radicals in the amygdala.

  7. NADPH oxidase activation contributes to native low-density lipoprotein-induced proliferation of human aortic smooth muscle cells.

    PubMed

    Park, Il Hwan; Hwang, Hye Mi; Jeon, Byeong Hwa; Kwon, Hyung-Joo; Hoe, Kwang Lae; Kim, Young Myeong; Ryoo, Sungwoo

    2015-06-12

    Elevated plasma concentration of native low-density lipoprotein (nLDL) is associated with vascular smooth muscle cell (VSMC) activation and cardiovascular disease. We investigated the mechanisms of superoxide generation and its contribution to pathophysiological cell proliferation in response to nLDL stimulation. Lucigenin-induced chemiluminescence was used to measure nLDL-induced superoxide production in human aortic smooth muscle cells (hAoSMCs). Superoxide production was increased by nicotinamide adenine dinucleotide phosphate (NADPH) and decreased by NADPH oxidase inhibitors in nLDL-stimulated hAoSMC and hAoSMC homogenates, as well as in prepared membrane fractions. Extracellular signal-regulated kinase 1/2 (Erk1/2), protein kinase C-θ (PKCθ) and protein kinase C-β (PKCβ) were phosphorylated and maximally activated within 3 min of nLDL stimulation. Phosphorylated Erk1/2 mitogen-activated protein kinase, PKCθ and PKCβ stimulated interactions between p47phox and p22phox; these interactions were prevented by MEK and PKC inhibitors (PD98059 and calphostin C, respectively). These inhibitors decreased nLDL-dependent superoxide production and blocked translocation of p47phox to the membrane, as shown by epifluorescence imaging and cellular fractionation experiments. Proliferation assays showed that a small interfering RNA against p47phox, as well as superoxide scavenger and NADPH oxidase inhibitors, blocked nLDL-induced hAoSMC proliferation. The nLDL stimulation in deendothelialized aortic rings from C57BL/6J mice increased dihydroethidine fluorescence and induced p47phox translocation that was blocked by PD98059 or calphostin C. Isolated aortic SMCs from p47phox(-/-) mice (mAoSMCs) did not respond to nLDL stimulation. Furthermore, NADPH oxidase 1 (Nox1) was responsible for superoxide generation and cell proliferation in nLDL-stimulated hAoSMCs. These data demonstrated that NADPH oxidase activation contributed to cell proliferation in nLDL-stimulated hAoSMCs.

  8. NADPH Oxidase Plays a Role on Ethanol-Induced Hypertension and Reactive Oxygen Species Generation in the Vasculature.

    PubMed

    Marchi, Katia Colombo; Ceron, Carla Speroni; Muniz, Jaqueline J; De Martinis, Bruno S; Tanus-Santos, José E; Tirapelli, Carlos Renato

    2016-09-01

    Investigate the role of NADPH oxidase on ethanol-induced hypertension and vascular oxidative stress. Male Wistar rats were treated with ethanol (20% v/v). Apocynin (10 mg/kg/day, i.p.) prevented ethanol-induced hypertension. The increased contractility of endothelium-intact and endothelium-denuded aortic rings from ethanol-treated rats to phenylephrine was prevented by apocynin. Ethanol consumption increased superoxide anion (O2 (-)) generation and lipid peroxidation and apocynin prevented these responses. The decrease on plasma and vascular nitrate/nitrite (NOx) levels induced by ethanol was not prevented by apocynin. Treatment with ethanol did not affect aortic levels of hydrogen peroxide (H2O2) or reduced glutathione (GSH). Ethanol did not alter the activities of xanthine oxidase (XO), superoxide dismutase (SOD), catalase (CAT) and glutathione peroxidase (GPx). Ethanol increased the expression of Nox1, PKCδ, nNOS, SAPK/JNK and SOD2 in the rat aorta and apocynin prevented these responses. No difference on aortic expression of Nox2, Nox4, p47phox, Nox organizer 1 (Noxo1), eNOS and iNOS was detected after treatment with ethanol. Ethanol treatment did not alter the phosphorylation of SAPK/JNK, p38MAPK, c-Src, Rac1 or PKCδ. The major new finding of our study is that the increased vascular generation of reactive oxygen species (ROS) induced by ethanol is related to increased vascular Nox1/NADPH oxidase expression. This mechanism is involved in vascular dysfunction and hypertension induced by ethanol. Additionally, we conclude that ethanol consumption induces the expression of different proteins that regulate vascular contraction and growth and that NADPH oxidase-derived ROS play a role in such response. The key findings of our study are that ethanol-induced hypertension is mediated by NADPH oxidase. Moreover, increased vascular Nox1 expression is related to the generation of reactive oxygen species (ROS) by ethanol. Finally, ROS induced by ethanol increase the

  9. NADPH oxidase deficiency underlies dysfunction of aged CD8+ Tregs

    PubMed Central

    Wen, Zhenke; Shimojima, Yasuhiro; Shirai, Tsuyoshi; Li, Yinyin; Ju, Jihang; Yang, Zhen; Tian, Lu; Goronzy, Jörg J.

    2016-01-01

    Immune aging results in progressive loss of both protective immunity and T cell–mediated suppression, thereby conferring susceptibility to a combination of immunodeficiency and chronic inflammatory disease. Here, we determined that older individuals fail to generate immunosuppressive CD8+CCR7+ Tregs, a defect that is even more pronounced in the age-related vasculitic syndrome giant cell arteritis. In young, healthy individuals, CD8+CCR7+ Tregs are localized in T cell zones of secondary lymphoid organs, suppress activation and expansion of CD4 T cells by inhibiting the phosphorylation of membrane-proximal signaling molecules, and effectively inhibit proliferative expansion of CD4 T cells in vitro and in vivo. We identified deficiency of NADPH oxidase 2 (NOX2) as the molecular underpinning of CD8 Treg failure in the older individuals and in patients with giant cell arteritis. CD8 Tregs suppress by releasing exosomes that carry preassembled NOX2 membrane clusters and are taken up by CD4 T cells. Overexpression of NOX2 in aged CD8 Tregs promptly restored suppressive function. Together, our data support NOX2 as a critical component of the suppressive machinery of CD8 Tregs and suggest that repairing NOX2 deficiency in these cells may protect older individuals from tissue-destructive inflammatory disease, such as large-vessel vasculitis. PMID:27088800

  10. Electron spin resonance characterization of vascular xanthine and NAD(P)H oxidase activity in patients with coronary artery disease: relation to endothelium-dependent vasodilation.

    PubMed

    Spiekermann, Stephan; Landmesser, Ulf; Dikalov, Sergey; Bredt, Martin; Gamez, Graciela; Tatge, Helma; Reepschläger, Nina; Hornig, Burkhard; Drexler, Helmut; Harrison, David G

    2003-03-18

    Increased inactivation of nitric oxide by superoxide (O2*-) contributes to endothelial dysfunction in patients with coronary disease (CAD). We therefore characterized the vascular activities of xanthine oxidase and NAD(P)H oxidase, 2 major O2*--producing enzyme systems, and their relationship with flow-dependent, endothelium-mediated vasodilation (FDD) in patients with CAD. Xanthine- and NAD(P)H-mediated O*.- formation was determined in coronary arteries from 10 patients with CAD and 10 controls by using electron spin resonance spectroscopy. Furthermore, activity of endothelium-bound xanthine oxidase in vivo and FDD of the radial artery were determined in 21 patients with CAD and 10 controls. FDD was measured before and after infusion of the antioxidant vitamin C (25 mg/min i.a.) to determine the portion of FDD inhibited by radicals. In coronary arteries from patients with CAD, xanthine- and NAD(P)H-mediated O2*- formation was increased compared with controls (xanthine: 12+/-2 versus 7+/-1 nmol O2*-/ microg protein; NADH: 11+/-1 versus 7+/-1 nmol O2*-/ microg protein; and NADPH: 12+/-2 versus 9+/-1 nmol O2*-/ microg protein; each P<0.05). Endothelium-bound xanthine oxidase activity was increased by >200% in patients with CAD (25+/-4 versus 9+/-1 nmol O2*-/ microL plasma per min; P<0.05) and correlated inversely with FDD (r=-0.55; P<0.05) and positively with the effect of vitamin C on FDD (r=0.54; P<0.05). The present study represents the first electron spin resonance measurements of xanthine and NAD(P)H oxidase activity in human coronary arteries and supports the concept that increased activities of both enzymes contribute to increased vascular oxidant stress in patients with CAD. Furthermore, the present study suggests that increased xanthine oxidase activity contributes to endothelial dysfunction in patients with CAD and may thereby promote the atherosclerotic process.

  11. Atrial myocardial nox2 containing NADPH oxidase activity contribution to oxidative stress in mitral regurgitation: potential mechanism for atrial remodeling.

    PubMed

    Chang, Jen-Ping; Chen, Mien-Cheng; Liu, Wen-Hao; Yang, Cheng-Hsu; Chen, Chien-Jen; Chen, Yung-Lung; Pan, Kuo-Li; Tsai, Tzu-Hsien; Chang, Hsueh-Wen

    2011-01-01

    Oxidative stress is linked with several cardiovascular diseases. However, the NADPH oxidase activity in severe mitral regurgitation patients with and without atrial fibrillation has not yet been explored. This study involved 16 adult patients (eight patients with persistent atrial fibrillation and eight with sinus rhythm) with severe mitral and moderate-to-severe tricuspid regurgitation and five control patients without mitral and tricuspid disease. Atrial tissues of the right and left atrial appendages were obtained during surgery. Superoxide anion production was measured by lucigenin-enhanced chemiluminescence, and the expression of nox2 containing NADPH oxidase mRNA was measured by quantitative real-time RT-PCR. Additionally, immunohistochemical study was performed. NADPH-stimulated superoxide release was significantly higher than basal superoxide production from right [5671.9±3498.7 vs. 232.7±70.0 relative light units per second per milligram of protein (RLU s(-1) mg protein(-1)), P=.008) and left atrial homogenates (6475.1±1890.8 vs. 229.0±79.6 RLU s(-1) mg protein(-1), P=.008) in atrial fibrillation patients. The NADPH-stimulated superoxide release from right atrial homogenates was also significantly higher than basal superoxide production in sinus patients (6809.1±1327.1 vs. 244.2±65.5 RLU s(-1) mg protein(-1), P=.008). Additionally, there was a borderline significant correlation between NADPH-stimulated superoxide production from left atrial homogenates and left atrial sizes (r=0.683, P=.062) in atrial fibrillation patients. Membrane-bound nox2 containing NADPH oxidase mRNA expression was increased and was similar in both the atrial fibrillation patients and sinus patients. The NADPH-stimulated superoxide production in right atrial homogenates in control atrial samples was 1863.7±137.2 RLU s(-1) mg protein(-1). Immunohistochemical study demonstrated increased expression of nox2 in myocytes with moderate-to-severe myolysis and hypertrophy. Results of

  12. Cross-talk between NADPH oxidase-PKCα-p(38)MAPK and NF-κB-MT1MMP in activating proMMP-2 by ET-1 in pulmonary artery smooth muscle cells.

    PubMed

    Sarkar, Jaganmay; Chowdhury, Animesh; Chakraborti, Tapati; Chakraborti, Sajal

    2016-04-01

    Treatment of bovine pulmonary artery smooth muscle cells with endothelin-1 (ET-1) caused an increase in the expression and activation of proMMP-2 in the cells. The present study was undertaken to determine the underlying mechanisms involved in this scenario. We demonstrated that (i) pretreatment with NADPH oxidase inhibitor, apocynin; PKC-α inhibitor, Go6976; p(38)MAPK inhibitor SB203580 and NF-κB inhibitor, Bay11-7082 inhibited the expression and activation of proMMP-2 induced by ET-1; (ii) ET-1 treatment to the cells stimulated NADPH oxidase and PKCα activity, p(38)MAPK phosphorylation as well as NF-κB activation by translocation of NF-κBp65 subunit from cytosol to the nucleus, and subsequently by increasing its DNA-binding activity; (iii) ET-1 increases MT1-MMP expression, which was inhibited upon pretreatment with apocynin, Go6976, SB293580, and Bay 11-7082; (iv) ET-1 treatment to the cells downregulated TIMP-2 level. Although apocynin and Go6976 pretreatment reversed ET-1 effect on TIMP-2 level, yet pretreatment of the cells with SB203580 and Bay 11-7082 did not show any discernible change in TIMP-2 level by ET-1. Overall, our results suggest that ET-1-induced activation of proMMP-2 is mediated via cross-talk between NADPH oxidase-PKCα-p(38)MAPK and NFκB-MT1MMP signaling pathways along with a marked decrease in TIMP-2 expression in the cells.

  13. Oscillatory shear stress stimulates endothelial production of O2- from p47phox-dependent NAD(P)H oxidases, leading to monocyte adhesion

    NASA Technical Reports Server (NTRS)

    Hwang, Jinah; Saha, Aniket; Boo, Yong Chool; Sorescu, George P.; McNally, J. Scott; Holland, Steven M.; Dikalov, Sergei; Giddens, Don P.; Griendling, Kathy K.; Harrison, David G.; hide

    2003-01-01

    Arterial regions exposed to oscillatory shear (OS) in branched arteries are lesion-prone sites of atherosclerosis, whereas those of laminar shear (LS) are relatively well protected. Here, we examined the hypothesis that OS and LS differentially regulate production of O2- from the endothelial NAD(P)H oxidase, which, in turn, is responsible for their opposite effects on a critical atherogenic event, monocyte adhesion. We used aortic endothelial cells obtained from C57BL/6 (MAE-C57) and p47phox-/- (MAE-p47-/-) mice, which lack a component of NAD(P)H oxidase. O2- production was determined by dihydroethidium staining and an electron spin resonance using an electron spin trap methoxycarbonyl-2,2,5,5-tetramethyl-pyrrolidine. Chronic exposure (18 h) to an arterial level of OS (+/- 5 dynes/cm2) increased O2- (2-fold) and monocyte adhesion (3-fold) in MAE-C57 cells, whereas chronic LS (15 dynes/cm2, 18 h) significantly decreased both monocyte adhesion and O2- compared with static conditions. In contrast, neither LS nor OS were able to induce O2- production and monocyte adhesion to MAE-p47-/-. Treating MAE-C57 with a cell-permeable superoxide dismutase compound, polyethylene glycol-superoxide dismutase, also inhibited OS-induced monocyte adhesion. In addition, over-expressing p47phox in MAE-p47-/- restored OS-induced O2- production and monocyte adhesion. These results suggest that chronic exposure of endothelial cells to OS stimulates O2- and/or its derivatives produced from p47phox-dependent NAD(P)H oxidase, which, in turn, leads to monocyte adhesion, an early and critical atherogenic event.

  14. Andrographolide Antagonizes TNF-α-Induced IL-8 via Inhibition of NADPH Oxidase/ROS/NF-κB and Src/MAPKs/AP-1 Axis in Human Colorectal Cancer HCT116 Cells.

    PubMed

    Yuan, Miaomiao; Meng, Wei; Liao, Wenzhen; Lian, Sen

    2018-05-14

    Andrographis paniculata Nees is used as a functional food in Japan, Korea, India, and China. Andrographolide, a naturally occurring phytochemical identified in Andrographis paniculata, has been discovered to present anti-inflammatory and anticancer activities. Highly expressed interleukin (IL-8) has been detected in colorectal cancer and is implicated in angiogenesis. However, the effect and molecular mechanisms of IL-8 expression by andrographolide remain obscure in human colorectal cancer cells. The present study was aimed to investigate the effects of andrographolide on TNF-α-induced IL-8 expression and its underlying mechanisms. We found that andrographolide concentration-dependently inhibited TNF-α-induced IL-8 mRNA (2.23 ± 0.15 fold at 20 μM) and protein expression (4.78 ± 0.31 fold at 20 μM) and reduced the IL-8 transcriptional activity (2.59 ± 0.25 fold at 20 μM). TNF-α stimulated the membrane translocation of p47 phox to activate reactive oxygen species (ROS)-producing NADPH oxidase (NOX). Furthermore, TNF-α induced Src and MAPKs (Erk1/2, p38 MAPK) phosphorylation, as well as NF-κB and AP-1 binding activities. We found that NF-κB and AP-1 were the critical transcription factors for TNF-α-induced IL-8 expression. Specific inhibitors and mutagenesis studies indicated that Src, Erk1/2, and p38 MAPK are related to TNF-α-induced IL-8. NOX-derived ROS and Src/MAPKs (Erk1/2 and p38 MAPK) functioned as upstream activators of NF-κB and AP-1, respectively. Taken together, andrographolide antagonizes TNF-α-induced IL-8 via inhibition of NADPH oxidase/ROS/NF-κB and Src/MAPKs/AP-1 signaling pathways in HCT116 colorectal cancer cells and then suppresses angiogenesis in the tumor microenvironment.

  15. Two NADPH oxidase isoforms are required for sexual reproduction and ascospore germination in the filamentous fungus Podospora anserina.

    PubMed

    Malagnac, Fabienne; Lalucque, Hervé; Lepère, Gersende; Silar, Philippe

    2004-11-01

    NADPH oxidases are enzymes that produce reactive oxygen species (ROS) using electrons derived from intracellular NADPH. In plants and mammals, ROS have been proposed to be second messengers that signal defence responses or cell proliferation. By inactivating PaNox1 and PaNox2, two genes encoding NADPH oxidases, we demonstrate the crucial role of these enzymes in the control of two key steps of the filamentous fungus Podospora anserina life cycle. PaNox1 mutants are impaired in the differentiation of fruiting bodies from their progenitor cells, and the deletion of the PaNox2 gene specifically blocks ascospore germination. Furthermore, we show that PaNox1 likely acts upstream of PaASK1, a MAPKKK previously implicated in stationary phase differentiation and cell degeneration. Using nitro blue tetrazolium (NBT) and diaminobenzidine (DAB) assays, we detect a regulated secretion of both superoxide and peroxide during P. anserina vegetative growth. In addition, two oxidative bursts are shown to occur during fruiting body development and ascospore germination. Analysis of mutants establishes that PaNox1, PaNox2, and PaASK1, as well as a still unknown additional source of ROS, modulate these secretions. Altogether, our data point toward a role for NADPH oxidases in signalling fungal developmental transitions with respect to nutrient availability. These enzymes are conserved in other multicellular eukaryotes, suggesting that early eukaryotes were endowed with a redox network used for signalling purposes.

  16. NADPH oxidase contributes to coronary endothelial dysfunction in the failing heart.

    PubMed

    Zhang, Ping; Hou, Mingxiao; Li, Yunfang; Xu, Xin; Barsoum, Michel; Chen, Yingjie; Bache, Robert J

    2009-03-01

    Increased reactive oxygen species (ROS) produced by the failing heart can react with nitric oxide (NO), thereby decreasing NO bioavailability. This study tested the hypothesis that increased ROS generation contributes to coronary endothelial dysfunction in the failing heart. Congestive heart failure (CHF) was produced in six dogs by ventricular pacing at 240 beats/min for 4 wk. Studies were performed at rest and during treadmill exercise under control conditions and after treatment with the NADPH oxidase inhibitor and antioxidant apocynin (4 mg/kg iv). Apocynin caused no significant changes in heart rate, aortic pressure, left ventricular (LV) systolic pressure, LV end-diastolic pressure, or maximum rate of LV pressure increase at rest or during exercise in normal or CHF dogs. Apocynin caused no change in coronary blood flow (CBF) in normal dogs but increased CBF at rest and during exercise in animals with CHF (P < 0.05). Intracoronary ACh caused dose-dependent increases of CBF that were blunted in CHF. Apocynin had no effect on the response to ACh in normal dogs but augmented the response to ACh in CHF dogs (P < 0.05). The oxidative stress markers nitrotyrosine and 4-hydroxy-2-nonenal were significantly greater in failing than in normal myocardium. Furthermore, coelenterazine chemiluminescence for O(2)(-) was more than twice normal in failing myocardium, and this difference was abolished by apocynin. Western blot analysis of myocardial lysates demonstrated that the p47(phox) and p22(phox) subunits of NADPH were significantly increased in the failing hearts, while real-time PCR demonstrated that Nox2 mRNA was significantly increased. The data indicate that increased ROS generation in the failing heart is associated with coronary endothelial dysfunction and suggest that NADPH oxidase may contribute to this abnormality.

  17. Constitutive NOS uncoupling and NADPH oxidase upregulation in the penis of type 2 diabetic men with erectile dysfunction

    PubMed Central

    Musicki, Biljana; Burnett, Arthur L.

    2016-01-01

    Erectile dysfunction (ED) associated with type 2 diabetes mellitus (T2DM) involves dysfunctional nitric oxide (NO) signaling and increased oxidative stress in the penis. However, the mechanisms of endothelial NO synthase (eNOS) and neuronal NO synthase (nNOS) dysregulation, and the sources of oxidative stress, are not well defined, particularly at the human level. The objective of this study was to define whether uncoupled eNOS and nNOS, and NADPH oxidase upregulation, contribute to the pathogenesis of ED in T2DM men. Penile erectile tissue was obtained from 9 T2DM patients with ED who underwent penile prosthesis surgery for ED, and from 6 control patients without T2DM or ED who underwent penectomy for penile cancer. The dimer-to-monomer protein expression ratio, an indicator of uncoupling for both eNOS and nNOS, total protein expressions of eNOS and nNOS, as well as protein expressions of NADPH oxidase catalytic subunit gp91phox (an enzymatic source of oxidative stress) and 4-hydroxy-2-nonenal [4-HNE] and nitrotyrosine (markers of oxidative stress) were measured by Western blot in this tissue. In the erectile tissue of T2DM men, eNOS and nNOS uncoupling and protein expressions of NADPH oxidase subunit gp91phox, 4-HNE- and nitrotyrosine-modified proteins were significantly (p<0.05) increased compared to control values. Total eNOS and nNOS protein expressions were not significantly different between the groups. In conclusion, mechanisms of T2DM-associated ED in the human penis may involve uncoupled eNOS and nNOS and NADPH oxidase upregulation. Our description of molecular factors contributing to the pathogenesis of T2DM-associated ED at the human level is relevant for advancing clinically therapeutic approaches to restore erectile function in T2DM patients. PMID:28076881

  18. Deciphering the role of NADPH oxidase in complex interactions between maize (Zea mays L.) genotypes and cereal aphids.

    PubMed

    Sytykiewicz, Hubert

    2016-07-22

    Plant NADPH oxidases (NOXs) encompass a group of membrane-bound enzymes participating in formation of reactive oxygen species (ROS) under physiological conditions as well as in response to environmental stressors. The purpose of the survey was to unveil the role of NADPH oxidase in pro-oxidative responses of maize (Zea mays L.) seedling leaves exposed to cereal aphids' infestation. The impact of apteral females of bird cherry-oat aphid (Rhopalosiphum padi L.) and grain aphid (Sitobion avenae F.) feeding on expression levels of all four NADPH oxidase genes (rbohA, rbohB, rbohC, rbohD) and total activity of NOX enzyme in maize plants were investigated. In addition, inhibitory effect of diphenylene iodonium (DPI) pre-treatment on NOX activity and hydrogen peroxide content in aphid-stressed maize seedlings was studied. Leaf infestation biotests were accomplished on 14-day-old seedlings representing two aphid-resistant varieties (Ambrozja and Waza) and two aphid-susceptible ones (Tasty Sweet and Złota Karłowa). Insects' attack led to profound upregulation of rbohA and rbohD genes in tested host plants, lower elevations were noted in level of rbohB mRNA, whereas abundance of rbohC transcript was not significantly altered. It was uncovered aphid-induced enhancement of NOX activity in examined plants. Higher increases in expression of all investigated rboh genes and activity of NADPH oxidase occurred in tissues of more resistant maize cultivars than in susceptible ones. Furthermore, DPI treatment resulted in strong reduction of NOX activity and H2O2 accumulation in aphid-infested Z. mays plants, thus evidencing circumstantial role of the enzyme in insect-elicited ROS generation. Copyright © 2016 Elsevier Inc. All rights reserved.

  19. Identification of NADPH oxidase family members associated with cold stress in strawberry.

    PubMed

    Zhang, Yunting; Li, Yali; He, Yuwei; Hu, Wenjie; Zhang, Yong; Wang, Xiaorong; Tang, Haoru

    2018-04-01

    NADPH oxidase is encoded by a small gene family (Respiratory burst oxidase homologs, Rbohs ) and plays an important role in regulating various biological processes. However, little information about this gene family is currently available for strawberry. In this study, a total of seven Rboh genes were identified from strawberry through genomewide analysis. Gene structure analysis showed the number of exons ranged from 10 to 23, implying that this variation occurred in FvRboh genes by the insertion and distribution of introns; the order and approximate size of exons were relatively conserved. FvRbohC was predicted to localize to the thylakoid membrane of the chloroplast, while other members were computed to localize to the plasma membrane, indicating different functions. Amino acid sequence alignment, conserved domain, and motif analysis showed that all identified FvRbohs had typical features of plant Rbohs. Phylogenetic analysis of Rbohs from strawberry, grape, Arabidopsis, and rice suggested that the FvRbohs could be divided into five subgroups and showed a closer relationship with those from grape and Arabidopsis than those from rice. The expression patterns of FvRboh genes in root, stem, leaf, flower, and fruit revealed robust tissue specificity. The expression levels of FvRbohA and FvRbohD were quickly induced by cold stress, followed by an increase in NADPH oxidase activity, leading to O2- accumulation and triggering the antioxidant reaction by the transient increases in SOD activity. This suggested these two genes may be involved in cold stress and defense responses in strawberry.

  20. High glucose condition increases NADPH oxidase activity in endothelial microparticles that promote vascular inflammation.

    PubMed

    Jansen, Felix; Yang, Xiaoyan; Franklin, Bernardo S; Hoelscher, Marion; Schmitz, Theresa; Bedorf, Jörg; Nickenig, Georg; Werner, Nikos

    2013-04-01

    Diabetes is a major risk factor for cardiovascular diseases. Circulating endothelial microparticles (EMP) are increased in diabetic patients, but their potential contribution in atherogenesis is unclear. We sought to determine the role of EMP derived under high glucose conditions in the development of atherosclerosis. EMP were generated from human coronary endothelial cells (HCAEC) exposed to high glucose concentrations in order to mimic diabetic conditions. These EMP were defined as 'injured' EMP (iEMP) and their effects were compared with EMP generated from 'healthy' untreated HCAEC. iEMP injection significantly impaired endothelial function in ApoE(-/-) mice compared with EMP and vehicle treatment. Immunofluorescent experiments showed increased macrophage infiltration and adhesion protein expression in atherosclerotic lesions of iEMP-treated ApoE(-/-) mice compared with controls. To further investigate the underlying mechanism of iEMP-induced vascular inflammation, additional in vitro experiments were performed. iEMP, but not EMP, induced activation of HCAEC in a time- and dose-dependent manner and increased monocyte adhesion. Further experiments demonstrated that iEMP induced activation of HCAEC by phosphorylation of p38 into its biologically active form phospho-p38. Inhibition of p38 activation abrogated iEMP-dependent induction of adhesion proteins and monocyte adhesion on HCAEC. Moreover, we could demonstrate that iEMP show increased NADPH oxidase activity and contain significantly higher level of reactive oxygen species (ROS) than EMP. iEMP triggered ROS production in HCAEC and thereby activate p38 in an ROS-dependent manner. High glucose condition increases NADPH oxidase activity in endothelial microparticles that amplify endothelial inflammation and impair endothelial function by promoting activation of the endothelium. These findings provide new insights into the pathogenesis of diabetes-associated atherosclerosis.

  1. Nanometer size diesel exhaust particles are selectively toxic to dopaminergic neurons: the role of microglia, phagocytosis, and NADPH oxidase.

    PubMed

    Block, M L; Wu, X; Pei, Z; Li, G; Wang, T; Qin, L; Wilson, B; Yang, J; Hong, J S; Veronesi, B

    2004-10-01

    The contributing role of environmental factors to the development of Parkinson's disease has become increasingly evident. We report that mesencephalic neuron-glia cultures treated with diesel exhaust particles (DEP; 0.22 microM) (5-50 microg/ml) resulted in a dose-dependent decrease in dopaminergic (DA) neurons, as determined by DA-uptake assay and tyrosine-hydroxylase immunocytochemistry (ICC). The selective toxicity of DEP for DA neurons was demonstrated by the lack of DEP effect on both GABA uptake and Neu-N immunoreactive cell number. The critical role of microglia was demonstrated by the failure of neuron-enriched cultures to exhibit DEP-induced DA neurotoxicity, where DEP-induced DA neuron death was reinstated with the addition of microglia to neuron-enriched cultures. OX-42 ICC staining of DEP treated neuron-glia cultures revealed changes in microglia morphology indicative of activation. Intracellular reactive oxygen species and superoxide were produced from enriched-microglia cultures in response to DEP. Neuron-glia cultures from NADPH oxidase deficient (PHOX-/-) mice were insensitive to DEP neurotoxicity when compared with control mice (PHOX+/+). Cytochalasin D inhibited DEP-induced superoxide production in enriched-microglia cultures, implying that DEP must be phagocytized by microglia to produce superoxide. Together, these in vitro data indicate that DEP selectively damages DA neurons through the phagocytic activation of microglial NADPH oxidase and consequent oxidative insult.

  2. Arctigenin reduces blood pressure by modulation of nitric oxide synthase and NADPH oxidase expression in spontaneously hypertensive rats.

    PubMed

    Liu, Ying; Wang, Guoyuan; Yang, Mingguang; Chen, Haining; zhao, Yan; Yang, Shucai; Sun, Changhao

    2015-12-25

    Arctigenin is a bioactive constituent from dried seeds of Arctium lappa L., which was traditionally used as medicine. Arctigenin exhibits various bioactivities, but its effects on blood pressure regulation are still not widely studied. In this study, we investigated antihypertensive effects of arctigenin by long-term treatment in spontaneously hypertensive rats (SHRs). Arctigenin (50 mg/kg) or vehicle was administered to SHRs or Wistar rats as negative control by oral gavage once a day for total 8 weeks. Nifedipine (3 mg/kg) was used as a positive drug control. After treatment, hemodynamic and physical parameters, vascular reactivity in aorta, the concentration of plasma arctigenin and serum thromboxane B2, NO release and vascular p-eNOS, p-Akt, caveolin-1 protein expression, and vascular superoxide anion generation and p47phox protein expression were detected and analyzed. The results showed that arctigenin significantly reduced systolic blood pressure and ameliorated endothelial dysfunction of SHRs. Arctigenin reduced the levels of thromboxane B2 in plasma and superoxide anion in thoracic aorta of SHRs. Furthermore, arctigenin increased the NO production by enhancing the phosphorylation of Akt and eNOS (Ser 1177), and inhibiting the expression of NADPH oxidase in thoracic aorta of SHRs. Our data suggested that antihypertensive mechanisms of arctigenin were associated with enhanced eNOS phosphorylation and decreased NADPH oxidase-mediated superoxide anion generation. Copyright © 2015 Elsevier Inc. All rights reserved.

  3. NADPH oxidase is not an essential mediator of oxidative stress or liver injury in murine MCD diet-induced steatohepatitis.

    PubMed

    dela Peña, Aileen; Leclercq, Isabelle A; Williams, Jacqueline; Farrell, Geoffrey C

    2007-02-01

    Hepatic oxidative stress is a key feature of metabolic forms of steatohepatitis, but the sources of pro-oxidants are unclear. The NADPH oxidase complex is critical for ROS generation in inflammatory cells; loss of any one component (e.g., gp91phox) renders NADPH oxidase inactive. We tested whether activated inflammatory cells contribute to oxidant stress in steatohepatitis. gp91phox-/- and wildtype (wt) mice were fed a methionine and choline-deficient (MCD) diet. Serum ALT, hepatic triglycerides, histopathology, lipid peroxidation, activation of NF-kappaB, expression of NF-kappaB-regulated genes and macrophage chemokines were measured. After 10 days of MCD dietary feeding, gp91phox-/- and wt mice displayed equivalent hepatocellular injury. After 8 weeks, there were fewer activated macrophages in livers of gp91phox-/- mice than controls, despite similar mRNA levels for MCP and MIP chemokines, but fibrosis was similar. NF-kappaB activation and increased expression of ICAM-1, TNF-alpha and COX-2 mRNA were evident in both genotypes, but in gp91phox-/- mice, expression of these genes was confined to hepatocytes. A functional NADPH oxidase complex does not contribute importantly to oxidative stress in this model and therefore is not obligatory for induction or perpetuation of dietary steatohepatitis.

  4. The role of brassinosteroids in the regulation of the plasma membrane H+-ATPase and NADPH oxidase under cadmium stress.

    PubMed

    Jakubowska, Dagmara; Janicka, Małgorzata

    2017-11-01

    The present research aim was to define the role of brassinosteroids (BRs) in plant adaptation to cadmium stress. We observed a stimulating effect of exogenous BR on the activity of two plasma membrane enzymes which play a key role in plants adaptation to cadmium stress, H + -ATPase (EC 3.6.3.14) and NADPH oxidase (EC 1.6.3.1). Using anti-phosphothreonine antibody we showed that modification of PM H + -ATPase activity under BR action could result from phosphorylation of the enzyme protein. Also the relative expression of genes encoding both PM H + -ATPase and NADPH oxidase was affected by BR. To confirm the role of BR in the cadmium stimulating effect on activity of both studied plasma membrane enzymes, an assay in the presence of a BR biosynthesis inhibitor (propiconazole) was performed. Moreover, as a tool in our work we used commercially available plant mutants unable to BR biosynthesis or with dysfunctional BR signaling pathway, to further confirm participation of BR in plant adaptation to heavy metal stress. Presented results demonstrate some elements of the brassinosteroid-induced pathway activated under cadmium stress, wherein H + -ATPase and NADPH oxidase are key factors. Copyright © 2017 Elsevier B.V. All rights reserved.

  5. Mitochondrial complex I and NAD(P)H oxidase are major sources of exacerbated oxidative stress in pressure-overloaded ischemic-reperfused hearts.

    PubMed

    Mozaffari, Mahmood S; Baban, Babak; Liu, Jun Yao; Abebe, Worku; Sullivan, Jennifer C; El-Marakby, Ahmed

    2011-03-01

    We tested the hypothesis that pressure overload exacerbates oxidative stress associated with augmented mitochondrial permeability transition (MPT) pore opening and cell death in ischemic-reperfused hearts. Pressure overload decreased the level of reduced glutathione but increased nitrotyrosine and 8-hydroxydeoxyguanosine levels in ischemic-reperfused hearts. The activity of catalase, but not superoxide dismutase (SOD), was lower in ischemic-reperfused hearts perfused at higher pressure. Mitochondria from ischemic-reperfused hearts subjected to higher perfusion pressure displayed significantly greater [³H]-2-deoxyglucose-6-P entrapment suggestive of greater MPT pore opening and consistent with greater necrosis and apoptosis. Tempol (SOD mimetic) reduced infarct size in both groups but it remained greater in the higher pressure group. By contrast, uric acid (peroxynitrite scavenger) markedly reduced infarct size at higher pressure, effectively eliminating the differential between the two groups. Inhibition of xanthine oxidase, with allopurinol, reduced infarct size but did not eliminate the differential between the two groups. However, amobarbital (inhibitor of mitochondrial complex I) or apocynin [inhibitor of NAD(P)H oxidase] reduced infarct size at both pressures and also abrogated the differential between the two groups. Consistent with the effect of apocynin, pressure-overloaded hearts displayed significantly higher NAD(P)H oxidase activity. Furthermore, pressure-overloaded hearts displayed increased nitric oxide synthase activity which, along with increased propensity to superoxide generation, may underlie uric acid-induced cardioprotection. In conclusion, increased oxidative and nitrosative stress, coupled with lack of augmented SOD and catalase activities, contributes importantly to the exacerbating impact of pressure overload on MPT pore opening and cell death in ischemic-reperfused hearts.

  6. Expression of NADPH Oxidase Isoform 1 (Nox1) in Human Placenta: Involvement in Preeclampsia

    PubMed Central

    Cui, X.-L.; Brockman, D.; Campos, B.; Myatt, L.

    2010-01-01

    Increased oxidative stress in the placenta has been associated with preeclampsia (PE), a clinical syndrome involving placental pathology. The enzymatic sources of reactive oxygen species in the human placenta are as yet unidentified. We hypothesized that NADPH oxidase is a main source of reactive oxygen species in the placenta and its expression may change in PE. Employing RTPCR, we have amplified a novel NADPH oxidase isoform Nox1 from human choriocarcinoma BeWo cells. Using polyclonal anti-peptide antiserum recognizing unique Nox1 peptide sequences, we identified by immunohistochemistry and cell fractionation that Nox1 protein localizes in the BeWo cell membrane structures. Immunohistochemistry of normal placental tissues showed that Nox1 was localized in syncytiotrophoblasts, in villous vascular endothelium, and in some stromal cells. At the immunohistochemical level Nox1 expression was significantly increased in syncytiotrophoblast and endothelial cells in placentas from patients with preeclampsia as compared to gestational age-matched controls. Western blot analysis of whole placental homogenate confirmed this increase. Our data suggests that increased Nox1 expression is associated with the increased oxidative stress found in these placentas. PMID:15993942

  7. NADPH Oxidase Deficiency: A Multisystem Approach

    PubMed Central

    Cicalese, Maria Pia; Delmonte, Ottavia; Migliavacca, Maddalena; Cirillo, Emilia; Violi, Francesco

    2017-01-01

    The immune system is a complex system able to recognize a wide variety of host agents, through different biological processes. For example, controlled changes in the redox state are able to start different pathways in immune cells and are involved in the killing of microbes. The generation and release of ROS in the form of an “oxidative burst” represent the pivotal mechanism by which phagocytic cells are able to destroy pathogens. On the other hand, impaired oxidative balance is also implicated in the pathogenesis of inflammatory complications, which may affect the function of many body systems. NADPH oxidase (NOX) plays a pivotal role in the production of ROS, and the defect of its different subunits leads to the development of chronic granulomatous disease (CGD). The defect of the different NOX subunits in CGD affects different organs. In this context, this review will be focused on the description of the effect of NOX2 deficiency in different body systems. Moreover, we will also focus our attention on the novel insight in the pathogenesis of immunodeficiency and inflammation-related manifestations and on the protective role of NOX2 deficiency against the development of atherosclerosis. PMID:29430280

  8. Activation of TRPM2 and TRPV1 Channels in Dorsal Root Ganglion by NADPH Oxidase and Protein Kinase C Molecular Pathways: a Patch Clamp Study.

    PubMed

    Nazıroğlu, Mustafa

    2017-03-01

    Despite considerable research, the mechanisms of neuropathic pain induced by excessive oxidative stress production and overload calcium ion (Ca 2+ ) entry in dorsal root ganglion (DRG) remain substantially unidentified. The transient receptor potential melastatin 2 (TRPM2) and vanilloid 1 (TRPV1) channels are activated with different stimuli including oxidative stress. TRPM2 and TRPV1 have been shown to be involved in induction of neuropathic pain. However, the activation mechanisms of TRPM2 and TRPV1 via NADPH oxidase and protein kinase C (PKC) pathways are poorly understood. In this study, I investigated the roles of NADPH oxidase and PKC on Ca 2+ entry through TRPM2 and TRPV1 channels in in vitro DRG neurons of rats. Rat DRG neurons were used in whole-cell patch clamp experiments. The H 2 O 2 -induced TRPM2 current densities were decreased by N-(p-amylcinnamoyl)anthranilic acid (ACA), and dose-dependent capsaicin (CAP) and H 2 O 2 -induced TRPV1 currents were inhibited by capsazepine (CPZ). The TRPV1 channel is activated in the DRG neurons by 0.01 mM capsaicin but not 0.001 mM or 0.05 mM capsaicin. TRPM2 and TRPV1 currents were increased by the PKC activator, phorbol myristate acetate (PMA), although the currents were decreased by ACA, CPZ, and the PKC inhibitor, bisindolylmaleimide I (BIM). Both channel currents were further increased by PMA + H 2 O 2 as compared to H 2 O 2 only. In the combined presence of PMA + BIM, no TRPM2 or TRPV1 currents were observed. The CAP and H 2 O 2 -induced TRPM2 current densities were also decreased by the NADPH oxidase inhibitors apocynin and N-Acetylcysteine. In conclusion, these results demonstrate a protective role for NADPH oxidase and PKC inhibitors on Ca 2+ entry through TRPM2 and TRPV1 channels in DRG neurons. Since excessive oxidative stress production and Ca 2+ entry are implicated in the pathophysiology of neuropathic pain, the findings may be relevant to the etiology and treatment of neuropathology in DRG neurons.

  9. Ethanol increases matrix metalloproteinase-12 expression via NADPH oxidase-dependent ROS production in macrophages

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

    Kim, Mi Jin; Nepal, Saroj; Lee, Eung-Seok

    2013-11-15

    Matrix metalloproteinase-12 (MMP-12), an enzyme responsible for degradation of extracellular matrix, plays an important role in the progression of various diseases, including inflammation and fibrosis. Although most of those are pathogenic conditions induced by ethanol ingestion, the effect of ethanol on MMP-12 has not been explored. In the present study, we investigated the effect of ethanol on MMP-12 expression and its potential mechanisms in macrophages. Here, we demonstrated that ethanol treatment increased MMP-12 expression in primary murine peritoneal macrophages and RAW 264.7 macrophages at both mRNA and protein levels. Ethanol treatment also significantly increased the activity of nicotinamide adenine dinucleotidemore » (NADPH) oxidase and the expression of NADPH oxidase-2 (Nox2). Pretreatment with an anti-oxidant (N-acetyl cysteine) or a selective inhibitor of NADPH oxidase (diphenyleneiodonium chloride (DPI)) prevented ethanol-induced MMP-12 expression. Furthermore, knockdown of Nox2 by small interfering RNA (siRNA) prevented ethanol-induced ROS production and MMP-12 expression in RAW 264.7 macrophages, indicating a critical role for Nox2 in ethanol-induced intracellular ROS production and MMP-12 expression in macrophages. We also showed that ethanol-induced Nox2 expression was suppressed by transient transfection with dominant negative IκB-α plasmid or pretreatment with Bay 11-7082, a selective inhibitor of NF-κB, in RAW 264.7 macrophages. In addition, ethanol-induced Nox2 expression was also attenuated by treatment with a selective inhibitor of p38 MAPK, suggesting involvement of p38 MAPK/NF-κB pathway in ethanol-induced Nox2 expression. Taken together, these results demonstrate that ethanol treatment elicited increase in MMP-12 expression via increase in ROS production derived from Nox2 in macrophages. - Highlights: • Ethanol increases ROS production through up-regulation of Nox2 in macrophages. • Enhanced oxidative stress contributes to

  10. Hypercholesterolemia-induced erectile dysfunction: endothelial nitric oxide synthase (eNOS) uncoupling in the mouse penis by NAD(P)H oxidase

    PubMed Central

    Musicki, Biljana; Liu, Tongyun; Lagoda, Gwen A.; Strong, Travis D.; Sezen, Sena F.; Johnson, Justin M.; Burnett, Arthur L.

    2010-01-01

    INTRODUCTION Hypercholesterolemia induces erectile dysfunction (ED) mostly by increasing oxidative stress and impairing endothelial function in the penis, but the mechanisms regulating reactive oxygen species (ROS) production in the penis are not understood. AIMS We evaluated whether hypercholesterolemia activates nicotinamide adenine dinucleotide phosphate (NAD[P]H) oxidase in the penis, providing an initial source of ROS to induce endothelial nitric oxide synthase (eNOS) uncoupling and endothelial dysfunction resulting in ED. METHODS Low-density-lipoprotein receptor (LDLR)–null mice were fed Western diet for 4 weeks to induce early-stage hyperlipidemia. Wild type (WT) mice fed regular chow served as controls. Mice received NAD(P)H oxidase inhibitor apocynin (10 mM in drinking water) or vehicle. Erectile function was assessed in response to cavernous nerve electrical stimulation. Markers of endothelial function (phospho [P]-vasodilator-stimulated-protein [VASP]-Ser-239), oxidative stress (4-hydroxy-2-nonenal [HNE]), sources of ROS (eNOS uncoupling and NAD[P]H oxidase subunits p67phox, p47phox, and gp91phox), P-eNOS-Ser-1177, and eNOS were measured by Western blot in penes. MAIN OUTCOME MEASURES Molecular mechanisms of ROS generation and endothelial dysfunction in hypercholesterolemia-induced ED. RESULTS Erectile response was significantly (P<0.05) reduced in hypercholesterolemic LDLR-null mice compared to WT mice. Relative to WT mice, hypercholesterolemia increased (P<0.05) protein expressions of NAD(P)H oxidase subunits p67phox, p47phox and gp91phox, eNOS uncoupling, and 4-HNE-modified proteins, and reduced (P<0.05) P-VASP-Ser-239 expression in the penis. Apocynin treatment of LDLR-null mice preserved (P<0.05) maximal intracavernosal pressure, and reversed (P < 0.05) the abnormalities in protein expressions of gp67phox and gp47phox, 4-HNE, P-VASP-Ser-239, and eNOS uncoupling in the penis. Apocynin treatment of WT mice did not affect any of these parameters

  11. p67(phox) terminates the phospholipase A(2)-derived signal for activation of NADPH oxidase (NOX2).

    PubMed

    Krishnaiah, Saikumari Y; Dodia, Chandra; Feinstein, Sheldon I; Fisher, Aron B

    2013-05-01

    The phospholipase A2 (PLA2)activity of phosphorylated peroxiredoxin 6 (Prdx6) is required for activation of NADPH oxidase (NOX2). We investigated the interaction of Prdx6 with p67(phox) and its effect on NOX2 activity. With the use of specific antibodies, coimmunoprecipitation of p67(phox) and phosphorylated Prdx6 was demonstrated with lysates of mouse pulmonary microvascular endothelial cells (MPMVECs) that were stimulated with angiotensin II; the interaction of p67(phox) with nonphosphorylated Prdx6 was relatively weak. Association of p67(phox) and phosphoPrdx6 in intact MPMVECs after angiotensin II stimulation was demonstrated by proximity ligation assay and was abolished by U0126, a MAP kinase inhibitor. By isothermal titration calorimetry, p67(phox) bound strongly to phosphoPrdx6 but bound poorly to Prdx6; phosphorylated p67(phox) did not bind to either Prdx6 or phosphoPrdx6. PLA2 activity of recombinant phosphoPrdx6 was decreased by >98% in the presence of p67(phox); the calculated dissociation constant (Kd) of the p67(phox): phosphoPrdx6 complex was 65 nM. PLA2 activity (MJ33 sensitive) in cell lysates following angiotensin II treatment of MPMVECs was increased by 85% following knockdown of p67(phox) with siRNA. These data indicate that p67(phox) binds to phosphoPrdx6 and inhibits its PLA2 activity, an interaction that could function to terminate the PLA2-mediated NOX2 activation signal.-Krishnaiah, S. Y., Dodia, C., Feinstein, S. I., and Fisher, A. B. p67(phox) terminates the phospholipase A2-derived signal for activation of NADPH oxidase (NOX2).

  12. The crystal structure of NAD(P)H oxidase from Lactobacillus sanfranciscensis: insights into the conversion of O2 into two water molecules by the flavoenzyme.

    PubMed

    Lountos, George T; Jiang, Rongrong; Wellborn, William B; Thaler, Tracey L; Bommarius, Andreas S; Orville, Allen M

    2006-08-15

    The FAD-dependent NAD(P)H oxidase from Lactobacillus sanfrancisensis (L.san-Nox2) catalyzes the oxidation of 2 equivalents of either NADH or NADPH and reduces 1 equivalent of O(2) to yield 2 equivalents of water. During steady-state turnover only 0.5% of the reducing equivalents are detected in solution as hydrogen peroxide, suggesting that it is not released from the enzyme after the oxidation of the first equivalent of NAD(P)H and reaction with O(2). Here we report the crystal structure of L.san-Nox2 to 1.8 A resolution. The enzyme crystallizes as a dimer with each monomer consisting of a FAD binding domain (residues 1-120), a NAD(P)H binding domain (residues 150-250), and a dimerization domain (residues 325-451). The electron density for the redox-active Cys42 residue located adjacent to the si-face FAD is consistent with oxidation to the sulfenic acid (Cys-SOH) state. The side chain of Cys42 is also observed in two conformations; in one the sulfenic acid is hydrogen bonded to His10 and in the other it hydrogen bonds with the FAD O2' atom. Surprisingly, the NAD(P)H binding domains each contain an ADP ligand as established by electron density maps and MALDI-TOF analysis of the ligands released from heat-denatured enzyme. The ADP ligand copurifies with the enzyme, and its presence does not inhibit enzyme activity. Consequently, we hypothesize that either NADPH or NADH substrates bind via a long channel that extends from the enzyme exterior and terminates at the FAD re-face. A homology model of the NADH oxidase from Lactococcus lactis (L.lac-Nox2) was also generated using the crystal structure of L.san-Nox2, which reveals several important similarities and differences between the two enzymes. HPLC analysis of ligands released from denatured L.lac-Nox2 indicates that it does not bind ADP, which correlates with the specificity of the enzyme for oxidation of NADH.

  13. Redox-mediated signal transduction by cardiovascular Nox NADPH oxidases.

    PubMed

    Brandes, Ralf P; Weissmann, Norbert; Schröder, Katrin

    2014-08-01

    The only known function of the Nox family of NADPH oxidases is the production of reactive oxygen species (ROS). Some Nox enzymes show high tissue-specific expression and the ROS locally produced are required for synthesis of hormones or tissue components. In the cardiovascular system, Nox enzymes are low abundant and function as redox-modulators. By reacting with thiols, nitric oxide (NO) or trace metals, Nox-derived ROS elicit a plethora of cellular responses required for physiological growth factor signaling and the induction and adaptation to pathological processes. The interactions of Nox-derived ROS with signaling elements in the cardiovascular system are highly diverse and will be detailed in this article, which is part of a Special Issue entitled "Redox Signalling in the Cardiovascular System". Copyright © 2014 Elsevier Ltd. All rights reserved.

  14. Hydrogen sulfide inhibits high glucose-induced NADPH oxidase 4 expression and matrix increase by recruiting inducible nitric oxide synthase in kidney proximal tubular epithelial cells.

    PubMed

    Lee, Hak Joo; Lee, Doug Yoon; Mariappan, Meenalakshmi M; Feliers, Denis; Ghosh-Choudhury, Goutam; Abboud, Hanna E; Gorin, Yves; Kasinath, Balakuntalam S

    2017-04-07

    High-glucose increases NADPH oxidase 4 (NOX4) expression, reactive oxygen species generation, and matrix protein synthesis by inhibiting AMP-activated protein kinase (AMPK) in renal cells. Because hydrogen sulfide (H 2 S) inhibits high glucose-induced matrix protein increase by activating AMPK in renal cells, we examined whether H 2 S inhibits high glucose-induced expression of NOX4 and matrix protein and whether H 2 S and NO pathways are integrated. High glucose increased NOX4 expression and activity at 24 h in renal proximal tubular epithelial cells, which was inhibited by sodium hydrosulfide (NaHS), a source of H 2 S. High glucose decreased AMPK phosphorylation and activity, which was restored by NaHS. Compound C, an AMPK inhibitor, prevented NaHS inhibition of high glucose-induced NOX4 expression. NaHS inhibition of high glucose-induced NOX4 expression was abrogated by N (ω)-nitro-l-arginine methyl ester, an inhibitor of NOS. NaHS unexpectedly augmented the expression of inducible NOS (iNOS) but not endothelial NOS. iNOS siRNA and 1400W, a selective iNOS inhibitor, abolished the ameliorative effects of NaHS on high glucose-induced NOX4 expression, reactive oxygen species generation, and, matrix laminin expression. Thus, H 2 S recruits iNOS to generate NO to inhibit high glucose-induced NOX4 expression, oxidative stress, and matrix protein accumulation in renal epithelial cells; the two gasotransmitters H 2 S and NO and their interaction may serve as therapeutic targets in diabetic kidney disease. © 2017 by The American Society for Biochemistry and Molecular Biology, Inc.

  15. Peroxisome proliferator-activated receptor δ inhibits Porphyromonas gingivalis lipopolysaccharide-induced activation of matrix metalloproteinase-2 by downregulating NADPH oxidase 4 in human gingival fibroblasts.

    PubMed

    Yoo, T; Ham, S A; Hwang, J S; Lee, W J; Paek, K S; Oh, J W; Kim, J H; Do, J T; Han, C W; Kim, J H; Seo, H G

    2016-10-01

    We investigated the roles of peroxisome proliferator-activated receptor δ (PPARδ) in Porphyromonas gingivalis-derived lipopolysaccharide (Pg-LPS)-induced activation of matrix metalloproteinase 2 (MMP-2). In human gingival fibroblasts (HGFs), activation of PPARδ by GW501516, a specific ligand of PPARδ, inhibited Pg-LPS-induced activation of MMP-2 and generation of reactive oxygen species (ROS), which was associated with reduced expression of NADPH oxidase 4 (Nox4). These effects were significantly smaller in the presence of small interfering RNA targeting PPARδ or the specific PPARδ inhibitor GSK0660, indicating that PPARδ is involved in these events. In addition, modulation of Nox4 expression by small interfering RNA influenced the effect of PPARδ on MMP-2 activity, suggesting a mechanism in which Nox4-derived ROS modulates MMP-2 activity. Furthermore, c-Jun N-terminal kinase and p38, but not extracellular signal-regulated kinase, mediated PPARδ-dependent inhibition of MMP-2 activity in HGFs treated with Pg-LPS. Concomitantly, PPARδ-mediated inhibition of MMP-2 activity was associated with the restoration of types I and III collagen to levels approaching those in HGFs not treated with Pg-LPS. These results indicate that PPARδ-mediated downregulation of Nox4 modulates cellular redox status, which in turn plays a critical role in extracellular matrix homeostasis through ROS-dependent regulation of MMP-2 activity. © 2015 John Wiley & Sons A/S. Published by John Wiley & Sons Ltd.

  16. NAD(P)H Oxidase Activity in the Small Intestine Is Predominantly Found in Enterocytes, Not Professional Phagocytes.

    PubMed

    Lindquist, Randall L; Bayat-Sarmadi, Jannike; Leben, Ruth; Niesner, Raluca; Hauser, Anja E

    2018-05-04

    The balance between various cellular subsets of the innate and adaptive immune system and microbiota in the gastrointestinal tract is carefully regulated to maintain tolerance to the normal flora and dietary antigens, while protecting against pathogens. The intestinal epithelial cells and the network of dendritic cells and macrophages in the lamina propria are crucial lines of defense that regulate this balance. The complex relationship between the myeloid compartment (dendritic cells and macrophages) and lymphocyte compartment (T cells and innate lymphoid cells), as well as the impact of the epithelial cell layer have been studied in depth in recent years, revealing that the regulatory and effector functions of both innate and adaptive immune compartments exhibit more plasticity than had been previously appreciated. However, little is known about the metabolic activity of these cellular compartments, which is the basic function underlying all other additional tasks the cells perform. Here we perform intravital NAD(P)H fluorescence lifetime imaging in the small intestine of fluorescent reporter mice to monitor the NAD(P)H-dependent metabolism of epithelial and myeloid cells. The majority of myeloid cells which comprise the surveilling network in the lamina propria have a low metabolic activity and remain resting even upon stimulation. Only a few myeloid cells, typically localized at the tip of the villi, are metabolically active and are able to activate NADPH oxidases upon stimulation, leading to an oxidative burst. In contrast, the epithelial cells are metabolically highly active and, although not considered professional phagocytes, are also able to activate NADPH oxidases, leading to massive production of reactive oxygen species. Whereas the oxidative burst in myeloid cells is mainly catalyzed by the NOX2 isotype, in epithelial cells other isotypes of the NADPH oxidases family are involved, especially NOX4. They are constitutively expressed by the epithelial

  17. Acute Ethanol Intake Induces NAD(P)H Oxidase Activation and Rhoa Translocation in Resistance Arteries.

    PubMed

    Simplicio, Janaina A; Hipólito, Ulisses Vilela; Vale, Gabriel Tavares do; Callera, Glaucia Elena; Pereira, Camila André; Touyz, Rhian M; Tostes, Rita de Cássia; Tirapelli, Carlos R

    2016-11-01

    The mechanism underlying the vascular dysfunction induced by ethanol is not totally understood. Identification of biochemical/molecular mechanisms that could explain such effects is warranted. To investigate whether acute ethanol intake activates the vascular RhoA/Rho kinase pathway in resistance arteries and the role of NAD(P)H oxidase-derived reactive oxygen species (ROS) on such response. We also evaluated the requirement of p47phox translocation for ethanol-induced NAD(P)H oxidase activation. Male Wistar rats were orally treated with ethanol (1g/kg, p.o. gavage) or water (control). Some rats were treated with vitamin C (250 mg/kg, p.o. gavage, 5 days) before administration of water or ethanol. The mesenteric arterial bed (MAB) was collected 30 min after ethanol administration. Vitamin C prevented ethanol-induced increase in superoxide anion (O2-) generation and lipoperoxidation in the MAB. Catalase and superoxide dismutase activities and the reduced glutathione, nitrate and hydrogen peroxide (H2O2) levels were not affected by ethanol. Vitamin C and 4-methylpyrazole prevented the increase on O2- generation induced by ethanol in cultured MAB vascular smooth muscle cells. Ethanol had no effect on phosphorylation levels of protein kinase B (Akt) and eNOS (Ser1177 or Thr495 residues) or MAB vascular reactivity. Vitamin C prevented ethanol-induced increase in the membrane: cytosol fraction ratio of p47phox and RhoA expression in the rat MAB. Acute ethanol intake induces activation of the RhoA/Rho kinase pathway by a mechanism that involves ROS generation. In resistance arteries, ethanol activates NAD(P)H oxidase by inducing p47phox translocation by a redox-sensitive mechanism. O mecanismo da disfunção vascular induzido pelo consumo de etanol não é totalmente compreendido. Justifica-se, assim a identificação de mecanismos bioquímicos e moleculares que poderiam explicar tais efeitos. Investigar se a ingestão aguda de etanol ativa a via vascular RhoA/Rho quinase

  18. 5-Hydroxytryptamine1A receptor/Gibetagamma stimulates mitogen-activated protein kinase via NAD(P)H oxidase and reactive oxygen species upstream of src in chinese hamster ovary fibroblasts.

    PubMed Central

    Mukhin, Y V; Garnovskaya, M N; Collinsworth, G; Grewal, J S; Pendergrass, D; Nagai, T; Pinckney, S; Greene, E L; Raymond, J R

    2000-01-01

    The hypothesis of this work is that the 'serotonin' or 5-hydroxytryptamine (5-HT)(1A) receptor, which activates the extracellular signal-regulated kinase (ERK) through a G(i)betagamma-mediated pathway, does so through the intermediate actions of reactive oxygen species (ROS). Five criteria were shown to support a key role for ROS in the activation of ERK by the 5-HT(1A) receptor. (1) Antioxidants inhibit activation of ERK by 5-HT. (2) Application of cysteine-reactive oxidant molecules activates ERK. (3) The 5-HT(1A) receptor alters cellular redox properties, and generates both superoxide and hydrogen peroxide. (4) A specific ROS-producing enzyme [NAD(P)H oxidase] is involved in the activation of ERK. (5) There is specificity both in the effects of various chemical oxidizers, and in the putative location of the ROS in the ERK activation pathway. We propose that NAD(P)H oxidase is located in the ERK activation pathway stimulated by the transfected 5-HT(1A) receptor in Chinese hamster ovary (CHO) cells downstream of G(i)betagamma subunits and upstream of or at the level of the non-receptor tyrosine kinase, Src. Moreover, these experiments provide confirmation that the transfected human 5-HT(1A) receptor induces the production of ROS (superoxide and hydrogen peroxide) in CHO cells, and support the possibility that an NAD(P)H oxidase-like enzyme might be involved in the 5-HT-mediated generation of both superoxide and hydrogen peroxide. PMID:10727402

  19. Thioredoxin-interacting Protein Mediates High Glucose-induced Reactive Oxygen Species Generation by Mitochondria and the NADPH Oxidase, Nox4, in Mesangial Cells*

    PubMed Central

    Shah, Anu; Xia, Ling; Goldberg, Howard; Lee, Ken W.; Quaggin, Susan E.; Fantus, I. George

    2013-01-01

    Thioredoxin-interacting protein (TxNIP) is up-regulated by high glucose and is associated with oxidative stress. It has been implicated in hyperglycemia-induced β-cell dysfunction and apoptosis. As high glucose and oxidative stress mediate diabetic nephropathy (DN), the contribution of TxNIP was investigated in renal mesangial cell reactive oxygen species (ROS) generation and collagen synthesis. To determine the role of TxNIP, mouse mesangial cells (MC) cultured from wild-type C3H and TxNIP-deficient Hcb-19 mice were incubated in HG. Confocal microscopy was used to measure total and mitochondrial ROS production (DCF and MitoSOX) and collagen IV. Trx and NADPH oxidase activities were assayed and NADPH oxidase isoforms, Nox2 and Nox4, and antioxidant enzymes were determined by immunoblotting. C3H MC exposed to HG elicited a significant increase in cellular and mitochondrial ROS as well as Nox4 protein expression and NADPH oxidase activation, whereas Hcb-19 MC showed no response. Trx activity was attenuated by HG only in C3H MC. These defects in Hcb-19 MC were not due to increased antioxidant enzymes or scavenging of ROS, but associated with decreased ROS generation. Adenovirus-mediated overexpression of TxNIP in Hcb-19 MC and TxNIP knockdown with siRNA in C3H confirmed the specific role of TxNIP. Collagen IV accumulation in HG was markedly reduced in Hcb-19 cells. TxNIP is a critical component of the HG-ROS signaling pathway, required for the induction of mitochondrial and total cell ROS and the NADPH oxidase isoform, Nox4. TxNIP is a potential target to prevent DN. PMID:23329835

  20. Congruence between PM H+-ATPase and NADPH oxidase during root growth: a necessary probability.

    PubMed

    Majumdar, Arkajo; Kar, Rup Kumar

    2018-07-01

    Plasma membrane (PM) H + -ATPase and NADPH oxidase (NOX) are two key enzymes responsible for cell wall relaxation during elongation growth through apoplastic acidification and production of ˙OH radical via O 2 ˙ - , respectively. Our experiments revealed a putative feed-forward loop between these enzymes in growing roots of Vigna radiata (L.) Wilczek seedlings. Thus, NOX activity was found to be dependent on proton gradient generated across PM by H + -ATPase as evident from pharmacological experiments using carbonyl cyanide m-chlorophenylhydrazone (CCCP; protonophore) and sodium ortho-vanadate (PM H + -ATPase inhibitor). Conversely, H + -ATPase activity retarded in response to different ROS scavengers [CuCl 2 , N, N' -dimethylthiourea (DMTU) and catalase] and NOX inhibitors [ZnCl 2 and diphenyleneiodonium (DPI)], while H 2 O 2 promoted PM H + -ATPase activity at lower concentrations. Repressing effects of Ca +2 antagonists (La +3 and EGTA) on the activity of both the enzymes indicate its possible mediation. Since, unlike animal NOX, the plant versions do not possess proton channel activity, harmonized functioning of PM H + -ATPase and NOX appears to be justified. Plasma membrane NADPH oxidase and H + -ATPase are functionally synchronized and they work cooperatively to maintain the membrane electrical balance while mediating plant cell growth through wall relaxation.

  1. Vitamin C prevents zidovudine-induced NAD(P)H oxidase activation and hypertension in the rat.

    PubMed

    Papparella, Italia; Ceolotto, Giulio; Berto, Laura; Cavalli, Maurizio; Bova, Sergio; Cargnelli, Gabriella; Ruga, Ezia; Milanesi, Ornella; Franco, Lorenzo; Mazzoni, Martina; Petrelli, Lucia; Nussdorfer, Gastone G; Semplicini, Andrea

    2007-01-15

    Cardiovascular risk is increased among HIV-infected patients receiving antiretroviral therapy due to the development of hypertension and metabolic abnormalities. In this study, we investigated the effects of long-term treatment with zidovudine (AZT) and vitamin C, alone and in combination, on blood pressure and on the chain of events linking oxidative stress to cardiac damage in the rat. Six adult Wistar Kyoto rats received AZT (1 mg/ml) in the drinking water for 8 months, six vitamin C (10 g/kg of food) and AZT, six vitamin C alone, and six served as controls. AZT increased systolic blood pressure, expression of gp91(phox) and p47(phox) subunits of NAD(P)H oxidase, and protein kinase C (PKC) delta activation and reduced antioxidant power of plasma and cardiac homogenates. AZT also caused morphological alterations in cardiac myocyte mitochondria, indicative of functional damage. All of these effects were prevented by vitamin C. Chronic AZT administration increases blood pressure and promotes cardiovascular damage through a NAD(P)H oxidase-dependent mechanism that involves PKC delta. Vitamin C antagonizes these adverse effects of AZT in the cardiovascular system.

  2. Chlorella Induces Stomatal Closure via NADPH Oxidase-Dependent ROS Production and Its Effects on Instantaneous Water Use Efficiency in Vicia faba

    PubMed Central

    Li, Yan; Xu, Shan-Shan; Gao, Jing; Pan, Sha; Wang, Gen-Xuan

    2014-01-01

    Reactive oxygen species (ROS) have been established to participate in stomatal closure induced by live microbes and microbe-associated molecular patterns (MAMPs). Chlorella as a beneficial microorganism can be expected to trigger stomatal closure via ROS production. Here, we reported that Chlorella induced stomatal closure in a dose-and time-dependent manner in epidermal peels of Vicia faba. Using pharmacological methods in this work, we found that the Chlorella-induced stomatal closure was almost completely abolished by a hydrogen peroxide (H2O2) scavenger, catalase (CAT), significantly suppressed by an NADPH oxidase inhibitor, diphenylene iodonium chloride (DPI), and slightly affected by a peroxidase inhibitor, salicylhydroxamic acid (SHAM), suggesting that ROS production involved in Chlorella-induced stomatal closure is mainly mediated by DPI-sensitive NADPH oxidase. Additionally, Exogenous application of optimal concentrations of Chlorella suspension improved instantaneous water use efficiency (WUEi) in Vicia faba via a reduction in leaf transpiration rate (E) without a parallel reduction in net photosynthetic rate (Pn) assessed by gas-exchange measurements. The chlorophyll fluorescence and content analysis further demonstrated that short-term use of Chlorella did not influence plant photosynthetic reactions center. These results preliminarily reveal that Chlorella can trigger stomatal closure via NADPH oxidase-dependent ROS production in epidermal strips and improve WUEi in leave levels. PMID:24687099

  3. Chlorella induces stomatal closure via NADPH oxidase-dependent ROS production and its effects on instantaneous water use efficiency in Vicia faba.

    PubMed

    Li, Yan; Xu, Shan-Shan; Gao, Jing; Pan, Sha; Wang, Gen-Xuan

    2014-01-01

    Reactive oxygen species (ROS) have been established to participate in stomatal closure induced by live microbes and microbe-associated molecular patterns (MAMPs). Chlorella as a beneficial microorganism can be expected to trigger stomatal closure via ROS production. Here, we reported that Chlorella induced stomatal closure in a dose-and time-dependent manner in epidermal peels of Vicia faba. Using pharmacological methods in this work, we found that the Chlorella-induced stomatal closure was almost completely abolished by a hydrogen peroxide (H2O2) scavenger, catalase (CAT), significantly suppressed by an NADPH oxidase inhibitor, diphenylene iodonium chloride (DPI), and slightly affected by a peroxidase inhibitor, salicylhydroxamic acid (SHAM), suggesting that ROS production involved in Chlorella-induced stomatal closure is mainly mediated by DPI-sensitive NADPH oxidase. Additionally, Exogenous application of optimal concentrations of Chlorella suspension improved instantaneous water use efficiency (WUEi) in Vicia faba via a reduction in leaf transpiration rate (E) without a parallel reduction in net photosynthetic rate (Pn) assessed by gas-exchange measurements. The chlorophyll fluorescence and content analysis further demonstrated that short-term use of Chlorella did not influence plant photosynthetic reactions center. These results preliminarily reveal that Chlorella can trigger stomatal closure via NADPH oxidase-dependent ROS production in epidermal strips and improve WUEi in leave levels.

  4. Aromatic Regions Govern the Recognition of NADPH Oxidase Inhibitors as Diapocynin and its Analogues.

    PubMed

    Macías Pérez, Martha E; Hernández Rodríguez, Maricarmen; Cabrera Pérez, Laura C; Fragoso-Vázquez, M Jonathan; Correa-Basurto, José; Padilla-Martínez, Itzia I; Méndez Luna, David; Mera Jiménez, Elvia; Flores Sandoval, César; Tamay Cach, Feliciano; Rosales-Hernández, Martha C

    2017-10-01

    Oxidative stress is related to the pathogenesis and progress of several human diseases. NADPH oxidase (NOX), and mainly the NOX2 isoform, produces superoxide anions (O 2 • - ). To date, it is known that NOX2 can be inhibited by preventing the assembly of its subunits, p47phox and p22phox. In this work, we analyzed the binding to NOX2 of the apocynin dimer, diapocynin (C1), a known NOX2 inhibitor, and of 18 designed compounds (C2-C19) which have chemical relationships to C1, by in silico methods employing a p47phox structure from the Protein Data Bank (PDB code: 1WLP). C1 and six of the designed compounds were recognized in the region where p22phox binds to p47phox and makes π-π interactions principally with W193, W263, and Y279, which form an aromatic-rich region. C8 was chosen as the best compound according to the in silico studies and was synthesized and evaluated in vitro. C8 was able to prevent the production of reactive oxygen species (ROS) similar to C1. In conclusion, targeting the aromatic region of p47phox through π-interactions is important for inhibiting NOX activity. © 2017 Deutsche Pharmazeutische Gesellschaft.

  5. Tea polyphenols alleviate high fat and high glucose-induced endothelial hyperpermeability by attenuating ROS production via NADPH oxidase pathway.

    PubMed

    Zuo, Xuezhi; Tian, Chong; Zhao, Nana; Ren, Weiye; Meng, Yi; Jin, Xin; Zhang, Ying; Ding, Shibin; Ying, Chenjiang; Ye, Xiaolei

    2014-03-02

    Hyperglycemia-induced endothelial hyperpermeability is crucial to cardiovascular disorders and macro-vascular complications in diabetes mellitus. The objective of this study is to investigate the effects of green tea polyphenols (GTPs) on endothelial hyperpermeability and the role of nicotinamide adenine dinucleotide phosphate (NADPH) pathway. Male Wistar rats fed on a high fat diet (HF) were treated with GTPs (0, 0.8, 1.6, 3.2 g/L in drinking water) for 26 weeks. Bovine aortic endothelial cells (BAECs) were treated with high glucose (HG, 33 mmol/L) and GTPs (0.0, 0.4, or 4 μg/mL) for 24 hours in vitro. The endothelial permeabilities in rat aorta and monolayer BAECs were measured by Evans blue injection method and efflux of fluorescein isothiocyanate (FITC)-dextran, respectively. The reactive oxygen species (ROS) levels in rat aorta and monolayer BAECs were measured by dihydroethidium (DHE) and 2', 7'-dichloro-fluorescein diacetate (DCFH-DA) fluorescent probe, respectively. Protein levels of NADPH oxidase subunits were determined by Western-blot. HF diet-fed increased the endothelial permeability and ROS levels in rat aorta while HG treatments increased the endothelial permeability and ROS levels in cultured BAECs. Co-treatment with GTPs alleviated those changes both in vivo and in vitro. In in vitro studies, GTPs treatments protected against the HG-induced over-expressions of p22phox and p67phox. Diphenylene iodonium chloride (DPI), an inhibitor of NADPH oxidase, alleviated the hyperpermeability induced by HG. GTPs could alleviate endothelial hyperpermeabilities in HF diet-fed rat aorta and in HG treated BAECs. The decrease of ROS production resulting from down-regulation of NADPH oxidase contributed to the alleviation of endothelial hyperpermeability.

  6. Advanced oxidation protein products induce inflammatory response in fibroblast-like synoviocytes through NADPH oxidase -dependent activation of NF-κB.

    PubMed

    Zheng, Shuai; Zhong, Zhao-Ming; Qin, Shuai; Chen, Guo-Xian; Wu, Qian; Zeng, Ji-Huan; Ye, Wen-Bin; Li, Wei; Yuan, Kai; Yao, Ling; Chen, Jian-Ting

    2013-01-01

    Advanced oxidation protein products (AOPPs), a marker of oxidative stress, are prevalent in many kinds of disorders. Rheumatoid arthritis (RA), mainly resulting from the dysfunction of fibroblast-like synoviocytes (FLSs), is related to oxidative stress. Although the increased levels of AOPPs in RA patients were reported, the effect of AOPPs on FLSs function still remains unclear. Therefore, our study aims to investigate whether AOPPs have an effect on the inflammatory response of FLSs in vitro. FLSs obtained from both knees of rats were treated with or without AOPPs-modified rat serum albumin (AOPPs-RSA) in vitro. The mRNA and protein expression of tumor necrosis factor (TNF)-α, interleukin(IL)-1β, matrix metalloproteinases(MMP)-3, MMP-13 and vascular endothelial growth factor (VEGF) were measured by real-time quantitative polymerase chain reaction and enzyme-linked immunosorbent assay (ELISA), respectively. Reactive oxygen species (ROS) generation was detected by fluorescent microscope and fluorescence microplate reader. Immunoprecipitation, Co-Immunoprecipitation and western blot were performed to examine the activity of nicotinamide adenine dinucleotide phosphate (NADPH) oxidase and nuclear factor kappa B (NF-κB). Exposure of FLSs to AOPPs upregulated the mRNA and protein expression of TNF-α, IL-1β, MMP-3, MMP-13 and VEGF in a concentration dependent manner. AOPPs treatment triggered ROS production in FLSs, which was significantly abolished by ROS scavenger N-acetyl-L-cysteine (NAC), superoxide dismutase (SOD), NADPH oxidase inhibitors diphenyleneiodonium (DPI) and apocynin. Challenged AOPPs induced phosphorylation of p47(phox), triggered an interaction between p47(phox), p22(phox) and gp91(phox), and significantly upregulated expression of NADPH oxidase subunits p47(phox), p22(phox) and gp91(phox). IκB degradation and nuclear translocation of NF-κB p65 induced by AOPPs were significantly blocked by SOD, NAC, DPI and apocynin. These data indicate that

  7. Stimulation of the cardiac myocyte Na+-K+ pump due to reversal of its constitutive oxidative inhibition

    PubMed Central

    Chia, Karin K. M.; Liu, Chia-Chi; Hamilton, Elisha J.; Garcia, Alvaro; Fry, Natasha A.; Hannam, William; Figtree, Gemma A.

    2015-01-01

    Protein kinase C can activate NADPH oxidase and induce glutathionylation of the β1-Na+-K+ pump subunit, inhibiting activity of the catalytic α-subunit. To examine if signaling of nitric oxide-induced soluble guanylyl cyclase (sGC)/cGMP/protein kinase G can cause Na+-K+ pump stimulation by counteracting PKC/NADPH oxidase-dependent inhibition, cardiac myocytes were exposed to ANG II to activate NADPH oxidase and inhibit Na+-K+ pump current (Ip). Coexposure to 3-(5′-hydroxymethyl-2′-furyl)-1-benzylindazole (YC-1) to stimulate sGC prevented the decrease of Ip. Prevention of the decrease was abolished by inhibition of protein phosphatases (PP) 2A but not by inhibition of PP1, and it was reproduced by an activator of PP2A. Consistent with a reciprocal relationship between β1-Na+-K+ pump subunit glutathionylation and pump activity, YC-1 decreased ANG II-induced β1-subunit glutathionylation. The decrease induced by YC-1 was abolished by a PP2A inhibitor. YC-1 decreased phosphorylation of the cytosolic p47phox NADPH oxidase subunit and its coimmunoprecipitation with the membranous p22phox subunit, and it decreased O2·−-sensitive dihydroethidium fluorescence of myocytes. Addition of recombinant PP2A to myocyte lysate decreased phosphorylation of p47phox indicating the subunit could be a substrate for PP2A. The effects of YC-1 to decrease coimmunoprecipitation of p22phox and p47phox NADPH oxidase subunits and decrease β1-Na+-K+ pump subunit glutathionylation were reproduced by activation of nitric oxide-dependent receptor signaling. We conclude that sGC activation in cardiac myocytes causes a PP2A-dependent decrease in NADPH oxidase activity and a decrease in β1 pump subunit glutathionylation. This could account for pump stimulation with neurohormonal oxidative stress expected in vivo. PMID:26084308

  8. p67phox terminates the phospholipase A2-derived signal for activation of NADPH oxidase (NOX2)

    PubMed Central

    Krishnaiah, Saikumari Y.; Dodia, Chandra; Feinstein, Sheldon I.; Fisher, Aron B.

    2013-01-01

    The phospholipase A2 (PLA2)activity of phosphorylated peroxiredoxin 6 (Prdx6) is required for activation of NADPH oxidase (NOX2). We investigated the interaction of Prdx6 with p67phox and its effect on NOX2 activity. With the use of specific antibodies, coimmunoprecipitation of p67phox and phosphorylated Prdx6 was demonstrated with lysates of mouse pulmonary microvascular endothelial cells (MPMVECs) that were stimulated with angiotensin II; the interaction of p67phox with nonphosphorylated Prdx6 was relatively weak. Association of p67phox and phosphoPrdx6 in intact MPMVECs after angiotensin II stimulation was demonstrated by proximity ligation assay and was abolished by U0126, a MAP kinase inhibitor. By isothermal titration calorimetry, p67phox bound strongly to phosphoPrdx6 but bound poorly to Prdx6; phosphorylated p67phox did not bind to either Prdx6 or phosphoPrdx6. PLA2 activity of recombinant phosphoPrdx6 was decreased by >98% in the presence of p67phox; the calculated dissociation constant (Kd) of the p67phox: phosphoPrdx6 complex was 65 nM. PLA2 activity (MJ33 sensitive) in cell lysates following angiotensin II treatment of MPMVECs was increased by 85% following knockdown of p67phox with siRNA. These data indicate that p67phox binds to phosphoPrdx6 and inhibits its PLA2 activity, an interaction that could function to terminate the PLA2-mediated NOX2 activation signal.—Krishnaiah, S. Y., Dodia, C., Feinstein, S. I., and Fisher, A. B. p67phox terminates the phospholipase A2-derived signal for activation of NADPH oxidase (NOX2). PMID:23401562

  9. Importance of NADPH oxidase-mediated redox signaling in the detrimental effect of CRP on pancreatic insulin secretion.

    PubMed

    Chan, Pei-Chi; Wang, Ya-Chin; Chen, Yi-Ling; Hsu, Wan-Ning; Tian, Yu-Feng; Hsieh, Po-Shiuan

    2017-11-01

    Elevations in C-reactive protein (CRP) levels are positively correlated with the progress of type 2 diabetes mellitus. However, the effect of CRP on pancreatic insulin secretion is unknown. Here, we showed that purified human CRP impaired insulin secretion in isolated mouse islets and NIT-1 insulin-secreting cells in dose- and time-dependent manners. CRP increased NADPH oxidase-mediated ROS (reactive oxygen species) production, which simultaneously promoted the production of nitrotyrosine (an indicator of RNS, reactive nitrogen species) and TNFα, to diminish cell viability, insulin secretion in islets and insulin-secreting cells. These CRP-mediated detrimental effects on cell viability and insulin secretion were significantly reversed by adding NAC (a potent antioxidant), apocynin (a selective NADPH oxidase inhibitor), L-NAME (a non-selective nitric oxide synthase (NOS) inhibitor), aminoguanidine (a selective iNOS inhibitor), PDTC (a selective NFκB inhibitor) or Enbrel (an anti-TNFα fusion protein). However, CRP-induced ROS production failed to change after adding L-NAME, aminoguanidine or PDTC. In isolated islets and NIT-1 cells, the elevated nitrotyrosine contents by CRP pretreatment were significantly suppressed by adding L-NAME but not PDTC. Conversely, CRP-induced increases in TNF-α production were significantly reversed by administration of PDTC but not L-NAME. In addition, wild-type mice treated with purified human CRP showed significant decreases in the insulin secretion index (HOMA-β cells) and the insulin stimulation index in isolated islets that were reversed by the addition of L-NAME, aminoguanidine or NAC. It is suggested that CRP-activated NADPH-oxidase redox signaling triggers iNOS-mediated RNS and NFκB-mediated proinflammatory cytokine production to cause β cell damage in state of inflammation. Copyright © 2017 Elsevier Inc. All rights reserved.

  10. A Prenylated p47phox-p67phox-Rac1 Chimera Is a Quintessential NADPH Oxidase Activator

    PubMed Central

    Mizrahi, Ariel; Berdichevsky, Yevgeny; Casey, Patrick J.; Pick, Edgar

    2010-01-01

    The superoxide-generating NADPH oxidase complex of resting phagocytes includes cytochrome b559, a membrane-associated heterodimer composed of two subunits (Nox2 and p22phox), and four cytosolic proteins (p47phox, p67phox, Rac, and p40phox). Upon stimulation, the cytosolic components translocate to the membrane, as the result of a series of interactions among the cytosolic components and among the cytosolic components and cytochrome b559 and its phospholipid environment. We described the construction of a tripartite chimera (trimera) consisting of strategic domains of p47phox, p67phox, and Rac1, in which interactions among cytosolic components were replaced by fusion (Berdichevsky, Y., Mizrahi, A., Ugolev, Y., Molshanski-Mor, S., and Pick, E. (2007) J. Biol. Chem. 282, 22122–22139). We now fused green fluorescent protein (GFP) to the N terminus of the trimera and found the following. 1) The GFP-p47phox-p67phox-Rac1 trimera activates the oxidase in amphiphile-dependent and -independent (anionic phospholipid-enriched membrane) cell-free systems. 2) Geranylgeranylation of the GFP-trimera makes it a potent oxidase activator in unmodified (native) membranes and in the absence of amphiphile. 3) Prenylated GFP-trimera binds spontaneously to native membranes (as assessed by gel filtration and in-line fluorometry), forming a tight complex capable of NADPH-dependent, activator-independent superoxide production at rates similar to those measured in canonical cell-free systems. 4) Prenylation of the GFP-trimera supersedes completely the dependence of oxidase activation on the p47phox phox homology domain and, partially, on the Rac1 polybasic domain, but the requirement for Trp193 in p47phox persists. Prenylated GFP-p47phox-p67phox-Rac1 trimera acts as a quintessential single molecule oxidase activator of potential use in high throughput screening of inhibitors. PMID:20529851

  11. Oral butyrate reduces oxidative stress in atherosclerotic lesion sites by a mechanism involving NADPH oxidase down-regulation in endothelial cells.

    PubMed

    Aguilar, Edenil C; Santos, Lana Claudinez Dos; Leonel, Alda J; de Oliveira, Jamil Silvano; Santos, Elândia Aparecida; Navia-Pelaez, Juliana M; da Silva, Josiane Fernandes; Mendes, Bárbara Pinheiro; Capettini, Luciano S A; Teixeira, Lilian G; Lemos, Virginia S; Alvarez-Leite, Jacqueline I

    2016-08-01

    Butyrate is a 4-carbon fatty acid that has antiinflammatory and antioxidative properties. It has been demonstrated that butyrate is able to reduce atherosclerotic development in animal models by reducing inflammatory factors. However, the contribution of its antioxidative effects of butyrate on atherogenesis has not yet been studied. We investigated the influence of butyrate on oxidative status, reactive oxygen species (ROS) release and oxidative enzymes (NADPH oxidase and iNOS) in atherosclerotic lesions of ApoE(-/-) mice and in oxLDL-stimulated peritoneal macrophages and endothelial cells (EA.hy926). The lesion area in aorta was reduced while in the aortic valve, although lesion area was unaltered, superoxide production and protein nitrosylation were reduced in butyrate-supplemented mice. Peritoneal macrophages from the butyrate group presented a lower free radical release after zymosan stimulus. When endothelial cells were pretreated with butyrate before oxLDL stimulus, the CCL-2 and superoxide ion productions and NADPH oxidase subunit p22phox were reduced. In macrophage cultures, in addition to a reduction in ROS release, nitric oxide and iNOS expression were down-regulated. The data suggest that one mechanism related to the effect of butyrate on atherosclerotic development is the reduction of oxidative stress in the lesion site. The reduction of oxidative stress related to NADPH oxidase and iNOS expression levels associated to butyrate supplementation attenuates endothelium dysfunction and macrophage migration and activation in the lesion site. Copyright © 2016 Elsevier Inc. All rights reserved.

  12. Superoxide from NADPH oxidase upregulates type 5 phosphodiesterase in human vascular smooth muscle cells: inhibition with iloprost and NONOate.

    PubMed

    Muzaffar, S; Shukla, N; Bond, M; Sala-Newby, G B; Newby, A C; Angelini, G D; Jeremy, J Y

    2008-11-01

    To determine whether there is an association between vascular NADPH oxidase (NOX), superoxide, the small GTPase Rac(1) and PDE type 5 (PDE5) in human vascular smooth muscle cell (hVSMCs). hVSMCs were incubated with xanthine-xanthine oxidase (X-XO; a superoxide generating system) or the thromboxane A(2) analogue, U46619 (+/-superoxide dismutase (SOD) or apocynin) for 16 h. The expression of PDE5 and NOX-1 was assessed using Western blotting and superoxide measured. The role of Rac(1) in superoxide generation was assessed by overexpressing either the dominant-negative or constitutively active Rac isoforms. The effects of iloprost, DETA-NONOate and the Rho-kinase inhibitor, Y27632, on PDE5 and NOX-1 expression were also studied. Following 16 h incubation, U46619 and X-XO promoted the expression of PDE5 and NOX-1, an effect blocked by SOD or apocynin when co-incubated over the same time course. X-XO and U46619 both promoted the formation of superoxide. Overexpression of dominant-negative Rac(1) or addition of iloprost, DETA-NONOate or Y27632 completely blocked both superoxide release and PDE5 protein expression and activity. These data demonstrate that superoxide derived from NOX upregulates the expression of PDE5 in human VSMCs. As PDE5 hydrolyses cyclic GMP, this effect may blunt the vasculoprotective actions of NO.

  13. Trimer hydroxylated quinone (IIIHyQ) derived from apocynin targets cysteine residues of p47phox preventing the activation of human vascular NADPH oxidase

    PubMed Central

    Mora-Pale, Mauricio; Joon-Kwon, Seok; Linhardt, Robert J.; Dordick, Jonathan S.

    2012-01-01

    Enzymatic derived oligophenols from apocynin can be effective inhibitors of human vascular NADPH oxidase. An isolated IIIHyQ has been shown to inhibit endothelial NADPH oxidase with an IC50 ~30 nM. In vitro studies demonstrated that IIIHyQ is capable on disrupting the interaction between p47phox and p22phox, thereby blocking the activation of the Nox2 isoform. Herein, we report the role of key cysteine residues in p47phox as targets for the IIIHyQ. Incubation of p47phox with IIIHyQ results in a decrease of ~80% of the protein free cysteine residues; similar results were observed using 1,2- and 1,4-naphthoquinoes, while apocynin was unreactive. Mutants of p47phox, where each Cys was individually replaced by Ala (at residues 111, 196 and 378) and Gly (at residue 98), were generated to evaluate their individual importance in IIIHyQ-mediated inhibition of p47phox interaction with p22phox. Specific Michael addition on Cys196, within the N-SH3 domain, by the IIIHyQ is critical for disrupting the p47phox-p22phox interaction. When a C196A mutation was tested, the IIIHyQ was unable to disrupt the p47phox-p22phox interaction. However, the IIIHyQ was effective at disrupting this interaction with the other mutants, displaying IC50 values (4.9, 21.0, and 2.3 μM for the C111A, C378A, and C98G mutants, respectively) comparable to that of wild type p47phox. PMID:22240153

  14. Role of NADPH oxidases and reactive oxygen species in regulation of bone turnover and the skeletal toxicity of alcohol

    USDA-ARS?s Scientific Manuscript database

    Recent studies with genetically modified mice and dietary antioxidants have suggested an important role for superoxide derived from NADPH oxidase (NOX) enzymes and other reactive oxygen species (ROS) such as hydrogen peroxide in regulation of normal bone turnover during development and also in the r...

  15. Regulation of NADPH-dependent Nitric Oxide and reactive oxygen species signalling in endothelial and melanoma cells by a photoactive NADPH analogue

    PubMed Central

    Rouaud, Florian; Romero-Perez, Miguel; Wang, Huan; Lobysheva, Irina; Ramassamy, Booma; Henry, Etienne; Tauc, Patrick; Giacchero, Damien; Boucher, Jean-Luc; Deprez, Eric; Rocchi, Stéphane; Slama-Schwok, Anny

    2014-01-01

    Nitric Oxide (NO) and Reactive oxygen species (ROS) are endogenous regulators of angiogenesis-related events as endothelial cell proliferation and survival, but NO/ROS defect or unbalance contribute to cancers. We recently designed a novel photoactive inhibitor of NO-Synthases (NOS) called NS1, which binds their NADPH site in vitro. Here, we show that NS1 inhibited NO formed in aortic rings. NS1-induced NO decrease led to an inhibition of angiogenesis in a model of VEGF-induced endothelial tubes formation. Beside this effect, NS1 reduced ROS levels in endothelial and melanoma A375 cells and in aorta. In metastatic melanoma cells, NS1 first induced a strong decrease of VEGF and blocked melanoma cell cycle at G2/M. NS1 decreased NOX4 and ROS levels that could lead to a specific proliferation arrest and cell death. In contrast, NS1 did not perturb melanocytes growth. Altogether, NS1 revealed a possible cross-talk between eNOS- and NOX4 –associated pathways in melanoma cells via VEGF, Erk and Akt modulation by NS1 that could be targeted to stop proliferation. NS1 thus constitutes a promising tool that modulates NO and redox stresses by targeting and directly inhibiting eNOS and, at least indirectly, NADPH oxidase(s), with great potential to control angiogenesis. PMID:25296975

  16. Female mice lacking active nadph-oxidase enzymes are protected against “western diet”--induced obesity and metabolic syndrome

    USDA-ARS?s Scientific Manuscript database

    NADPH oxidase (Nox) enzymes have been implicated in regulation of adipocyte differentiation and inflammation in a variety of tissues. We examined the effects of feeding AIN-93G or a “Western diet” (WD) (45% fat, 0.5% cholesterol) on development of obesity and “metabolic syndrome” in wild type (WT) m...

  17. Implication of NADPH Oxidases in the Early Inflammation Process Generated by Cystic Fibrosis Cells

    PubMed Central

    Pongnimitprasert, Nushjira; Hurtado, Margarita; Lamari, Foudil; El Benna, Jamel; Dupuy, Corinne; Fay, Michèle; Foglietti, Marie-José; Bernard, Maguy; Gougerot-Pocidalo, Marie-Anne; Braut-Boucher, Françoise

    2012-01-01

    In cystic fibrosis (CF) patients, pulmonary inflammation is a major cause of morbidity and mortality. The aim of this study was to further investigate whether oxidative stress could be involved in the early inflammatory process associated with CF pathogenesis. We used a model of CFTR defective epithelial cell line (IB3-1) and its reconstituted CFTR control (S9) cell line cultured in various ionic conditions. This study showed that IB3-1 and S9 cells expressed the NADPH oxidases (NOXs) DUOX1/2 and NOX2 at the same level. Nevertheless, several parameters participating in oxidative stress (increased ROS production and apoptosis, decreased total thiol content) were observed in IB3-1 cells cultured in hypertonic environment as compared to S9 cells and were inhibited by diphenyleneiodonium (DPI), a well-known inhibitor of NOXs; besides, increased production of the proinflammatory cytokines IL-6 and IL-8 by IB3-1 cells was also inhibited by DPI as compared to S9 cells. Furthermore, calcium ionophore (A23187), which upregulates DUOX and NOX2 activities, strongly induced oxidative stress and IL-8 and IL-6 overexpression in IB3-1 cells. All these events were suppressed by DPI, supporting the involvement of NOXs in the oxidative stress, which can upregulate proinflammatory cytokine production by the airway CFTR-deficient cells and trigger early pulmonary inflammation in CF patients. PMID:24049649

  18. Dual Roles of Reactive Oxygen Species and NADPH Oxidase RBOHD in an Arabidopsis-Alternaria Pathosystem1[W

    PubMed Central

    Pogány, Miklós; von Rad, Uta; Grün, Sebastian; Dongó, Anita; Pintye, Alexandra; Simoneau, Philippe; Bahnweg, Günther; Kiss, Levente; Barna, Balázs; Durner, Jörg

    2009-01-01

    Arabidopsis (Arabidopsis thaliana) NADPH oxidases have been reported to suppress the spread of pathogen- and salicylic acid-induced cell death. Here, we present dual roles of RBOHD (for respiratory burst oxidase homolog D) in an Arabidopsis-Alternaria pathosystem, suggesting either initiation or prevention of cell death dependent on the distance from pathogen attack. Our data demonstrate that a rbohD knockout mutant exhibits increased spread of cell death at the macroscopic level upon inoculation with the fungus Alternaria brassicicola. However, the cellular patterns of reactive oxygen species accumulation and cell death are fundamentally different in the AtrbohD mutant compared with the wild type. Functional RBOHD causes marked extracellular hydrogen peroxide accumulation as well as cell death in distinct, single cells of A. brassicicola-infected wild-type plants. This single cell response is missing in the AtrbohD mutant, where infection triggers spreading-type necrosis preceded by less distinct chloroplastic hydrogen peroxide accumulation in large clusters of cells. While the salicylic acid analog benzothiadiazole induces the action of RBOHD and the development of cell death in infected tissues, the ethylene inhibitor aminoethoxyvinylglycine inhibits cell death, indicating that both salicylic acid and ethylene positively regulate RBOHD and cell death. Moreover, A. brassicicola-infected AtrbohD plants hyperaccumulate ethylene and free salicylic acid compared with the wild type, suggesting negative feedback regulation of salicylic acid and ethylene by RBOHD. We propose that functional RBOHD triggers death in cells that are damaged by fungal infection but simultaneously inhibits death in neighboring cells through the suppression of free salicylic acid and ethylene levels. PMID:19726575

  19. [Research on the mechanism and regulation of overtraining-related the function of neutrophils by the inhibitor of NADPH oxidase and glutamine supplementation].

    PubMed

    Dong, Jing-Mei; Chen, Pei-Jie

    2013-07-01

    To investigate the method and mechanism for exercise-related immunosuppression via the inhibitor of NADPH oxidase diphenyleneiodonium(DPI) and glutamine supplementation and on the function of neutrophils after overtraining. Fifty male Wistar rats were randomly divided into five groups: a negative control group (C), an overtraining group (E), an overtraining + DPI intervention group (D), an overtraining+ glutamine supplementation group(G) and combined glutamine + DPI intervention group(DG). After 36 - 40 h from the last training, eight rats were randomly selected from each group, and blood was sampled from the orbital vein. ELISAs were used to measure serum cytokine levels and lipid peroxidation in blood plasma. Flow cytometry was used to measure neutrophil respiratory burst and phagocytosis. The activity of NADPH oxidase was assessed by chemiluminescence and the gene expression of gp91(phox) and p47(phox) of the NADPH-oxidase subunit was checked by Western blot. Compared with group C, the plasma concentrations of NO increased in group G, and the NO, cytokine-induced neutrophil chemoattractant (CINC) concentrations in group DG increased significantly. The respiratory burst and phagocytosis function of neutrophils were decreased in group E, but in group DG were increased when compared with those of group E. After overtraining the expression of gp91(phox) and p47(phox) was up regulated in group E. There were no significant changes in other groups except group DG, in which the expression of gp91(phox) was down regulated. Compared with group E, the expression of gp91(phox) and p47(phox) was up regulated in group D, group G and group DG. The activation of NADPH oxidase is responsible for the production of superoxide anions, which may be related to the decrease in neutrophil function after over training and is the mechanism of exercise-related immunosuppression. The DPI treatment combined glutamine supplementation can reverse the decrease neutrophils function after

  20. Reactive oxygen species generation mediated by NADPH oxidase and PI3K/Akt pathways contribute to invasion of Streptococcus agalactiae in human endothelial cells

    PubMed Central

    de Oliveira, Jessica Silva Santos; Santos, Gabriela da Silva; Moraes, João Alfredo; Saliba, Alessandra Mattos; Barja-Fidalgo, Thereza Christina; Mattos-Guaraldi, Ana Luíza; Nagao, Prescilla Emy

    2018-01-01

    BACKGROUND Streptococcus agalactiae can causes sepsis, pneumonia, and meningitis in neonates, the elderly, and immunocompromised patients. Although the virulence properties of S. agalactiae have been partially elucidated, the molecular mechanisms related to reactive oxygen species (ROS) generation in infected human endothelial cells need further investigation. OBJECTIVES This study aimed to evaluate the influence of oxidative stress in human umbilical vein endothelial cells (HUVECs) during S. agalactiae infection. METHODS ROS production during S. agalactiae-HUVEC infection was detected using the probe CM-H2DCFDA. Microfilaments labelled with phalloidin-FITC and p47phox-Alexa 546 conjugated were analysed by immunofluorescence. mRNA levels of p47phox (NADPH oxidase subunit) were assessed using Real Time qRT-PCR. The adherence and intracellular viability of S. agalactiae in HUVECs with or without pre-treatment of DPI, apocynin (NADPH oxidase inhibitors), and LY294002 (PI3K inhibitor) were evaluated by penicillin/gentamicin exclusion. Phosphorylation of p47phox and Akt activation by S. agalactiae were evaluated by immunoblotting analysis. FINDINGS Data showed increased ROS production 15 min after HUVEC infection. Real-Time qRT-PCR and western blotting performed in HUVEC infected with S. agalactiae detected alterations in mRNA levels and activation of p47phox. Pre-treatment of endothelial cells with NADPH oxidase (DPI and apocynin) and PI3K/Akt pathway (LY294002) inhibitors reduced ROS production, bacterial intracellular viability, and generation of actin stress fibres in HUVECs infected with S. agalactiae. CONCLUSIONS ROS generation via the NADPH oxidase pathway contributes to invasion of S. agalactiae in human endothelial cells accompanied by cytoskeletal reorganisation through the PI3K/Akt pathway, which provides novel evidence for the involvement of oxidative stress in S. agalactiae pathogenesis. PMID:29641644

  1. Reactive oxygen species generation mediated by NADPH oxidase and PI3K/Akt pathways contribute to invasion of Streptococcus agalactiae in human endothelial cells.

    PubMed

    Oliveira, Jessica Silva Santos de; Santos, Gabriela da Silva; Moraes, João Alfredo; Saliba, Alessandra Mattos; Barja-Fidalgo, Thereza Christina; Mattos-Guaraldi, Ana Luíza; Nagao, Prescilla Emy

    2018-01-01

    BACKGROUND Streptococcus agalactiae can causes sepsis, pneumonia, and meningitis in neonates, the elderly, and immunocompromised patients. Although the virulence properties of S. agalactiae have been partially elucidated, the molecular mechanisms related to reactive oxygen species (ROS) generation in infected human endothelial cells need further investigation. OBJECTIVES This study aimed to evaluate the influence of oxidative stress in human umbilical vein endothelial cells (HUVECs) during S. agalactiae infection. METHODS ROS production during S. agalactiae-HUVEC infection was detected using the probe CM-H2DCFDA. Microfilaments labelled with phalloidin-FITC and p47phox-Alexa 546 conjugated were analysed by immunofluorescence. mRNA levels of p47phox (NADPH oxidase subunit) were assessed using Real Time qRT-PCR. The adherence and intracellular viability of S. agalactiae in HUVECs with or without pre-treatment of DPI, apocynin (NADPH oxidase inhibitors), and LY294002 (PI3K inhibitor) were evaluated by penicillin/gentamicin exclusion. Phosphorylation of p47phox and Akt activation by S. agalactiae were evaluated by immunoblotting analysis. FINDINGS Data showed increased ROS production 15 min after HUVEC infection. Real-Time qRT-PCR and western blotting performed in HUVEC infected with S. agalactiae detected alterations in mRNA levels and activation of p47phox. Pre-treatment of endothelial cells with NADPH oxidase (DPI and apocynin) and PI3K/Akt pathway (LY294002) inhibitors reduced ROS production, bacterial intracellular viability, and generation of actin stress fibres in HUVECs infected with S. agalactiae. CONCLUSIONS ROS generation via the NADPH oxidase pathway contributes to invasion of S. agalactiae in human endothelial cells accompanied by cytoskeletal reorganisation through the PI3K/Akt pathway, which provides novel evidence for the involvement of oxidative stress in S. agalactiae pathogenesis.

  2. Superoxide from NADPH oxidase upregulates type 5 phosphodiesterase in human vascular smooth muscle cells: inhibition with iloprost and NONOate

    PubMed Central

    Muzaffar, S; Shukla, N; Bond, M; Sala-Newby, G B; Newby, A C; Angelini, G D; Jeremy, J Y

    2008-01-01

    Background and purpose: To determine whether there is an association between vascular NADPH oxidase (NOX), superoxide, the small GTPase Rac1 and PDE type 5 (PDE5) in human vascular smooth muscle cell (hVSMCs). Experimental approach: hVSMCs were incubated with xanthine–xanthine oxidase (X-XO; a superoxide generating system) or the thromboxane A2 analogue, U46619 (±superoxide dismutase (SOD) or apocynin) for 16 h. The expression of PDE5 and NOX-1 was assessed using Western blotting and superoxide measured. The role of Rac1 in superoxide generation was assessed by overexpressing either the dominant-negative or constitutively active Rac isoforms. The effects of iloprost, DETA-NONOate and the Rho-kinase inhibitor, Y27632, on PDE5 and NOX-1 expression were also studied. Key results: Following 16 h incubation, U46619 and X-XO promoted the expression of PDE5 and NOX-1, an effect blocked by SOD or apocynin when co-incubated over the same time course. X-XO and U46619 both promoted the formation of superoxide. Overexpression of dominant-negative Rac1 or addition of iloprost, DETA-NONOate or Y27632 completely blocked both superoxide release and PDE5 protein expression and activity. Conclusions and implications: These data demonstrate that superoxide derived from NOX upregulates the expression of PDE5 in human VSMCs. As PDE5 hydrolyses cyclic GMP, this effect may blunt the vasculoprotective actions of NO. PMID:18660830

  3. Adverse effects of the classic antioxidant uric acid in adipocytes: NADPH oxidase-mediated oxidative/nitrosative stress.

    PubMed

    Sautin, Yuri Y; Nakagawa, Takahiko; Zharikov, Sergey; Johnson, Richard J

    2007-08-01

    Uric acid is considered a major antioxidant in human blood that may protect against aging and oxidative stress. Despite its proposed protective properties, elevated levels of uric acid are commonly associated with increased risk for cardiovascular disease and mortality. Furthermore, recent experimental studies suggest that uric acid may have a causal role in hypertension and metabolic syndrome. All these conditions are thought to be mediated by oxidative stress. In this study we demonstrate that differentiation of cultured mouse adipocytes is associated with increased production of reactive oxygen species (ROS) and uptake of uric acid. Soluble uric acid stimulated an increase in NADPH oxidase activity and ROS production in mature adipocytes but not in preadipocytes. The stimulation of NADPH oxidase-dependent ROS by uric acid resulted in activation of MAP kinases p38 and ERK1/2, a decrease in nitric oxide bioavailability, and an increase in protein nitrosylation and lipid oxidation. Collectively, our results suggest that hyperuricemia induces redox-dependent signaling and oxidative stress in adipocytes. Since oxidative stress in the adipose tissue has recently been recognized as a major cause of insulin resistance and cardiovascular disease, hyperuricemia-induced alterations in oxidative homeostasis in the adipose tissue might play an important role in these derangements.

  4. The NADPH-oxidase AtRbohI plays a positive role in drought-stress response in Arabidopsis thaliana

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

    He, Huan; Yan, Jingwei; Yu, Xiaoyun

    As the major resource of reactive oxygen species (ROS), the NADPH oxidases (Rbohs) have been shown to play important roles in plant cells under normal growth and stress conditions. Although many family members of Rbohs were studied, little is known about the function of RbohI in Arabidopsis thaliana. Here, we report that exogenous ABA application decreases RbohI expression and mannitol significantly increases RbohI expression at transcript level. The RbohI transcripts were strongly detected in dry seeds and roots. The loss-of-function mutant rbohI exhibited sensitivity to ABA and mannitol stress during germination. Furthermore, the lateral root growth of rbohI was severelymore » inhibited after treatment with mannitol stress. Overexpression of RbohI in Arabidopsis significantly improves the drought tolerance. Moreover, more H 2O 2 accumulated in RbohI overexpressors than in wild type plants in response to mannitol stress. Our conclusion is that AtRbohI functions in drought-stress response in Arabidopsis thaliana.« less

  5. Exercise Training, NADPH Oxidase p22phox Gene Polymorphisms, and Hypertension

    PubMed Central

    FEAIRHELLER, DEBORAH L.; BROWN, MICHAEL D.; PARK, JOON-YOUNG; BRINKLEY, TINA E.; BASU, SAMAR; HAGBERG, JAMES M.; FERRELL, ROBERT E.; FENTY-STEWART, NICOLA M.

    2010-01-01

    Introduction Oxidative stress that is mediated through NADPH oxidase activity plays a role in the pathology of hypertension, and aerobic exercise training reduces NADPH oxidase activity. The involvement of genetic variation in the p22phox (CYBA) subunit genes in individual oxidative stress responses to aerobic exercise training has yet to be examined in Pre and Stage 1 hypertensives. Methods Ninety-four sedentary Pre and Stage 1 hypertensive adults underwent 6 months of aerobic exercise training at a level of 70% V̇O2max to determine whether the CYBA polymorphisms, C242T and A640G, were associated with changes in urinary 8-iso-prostaglandin F2α (8-iso-PGF2α), urinary nitric oxide metabolites (NOx), and plasma total antioxidant capacity (TAC). Results Demographic and subject characteristics were similar among genotype groups for both polymorphisms. At baseline, a significant (P = 0.03) difference among the C2424T genotype groups in 8-iso-PGF2α levels was detected, with the TT homozygotes having the lowest levels and the CC homozygotes having the highest levels. However, no differences were found at baseline between the A640G genotype groups. After 6 months of aerobic exercise training, there was a significant increase in V̇O2max (P < 0.0001) in the entire study population. In addition, there were significant increases in both urinary 8-iso-PGF2α (P = 0.002) and plasma TAC (P = 0.03) levels and a significant decrease in endogenous urinary NOx (P < 0.0001). Overall, aerobic exercise training elicited no significant differences among genotype groups in either CYBA variant for any of the oxidative stress variables. Conclusions We found that compared with CYBA polymorphisms C242T and A640G, it was aerobic exercise training that had the greatest influence on the selected biomarkers; furthermore, our results suggest that the C242T CYBA variant influences baseline levels of urinary 8-iso-PGF2α but not the aerobic exercise-induced responses. PMID:19516159

  6. Persistent activation of microglia and NADPH drive hippocampal dysfunction in experimental multiple sclerosis

    PubMed Central

    Di Filippo, Massimiliano; de Iure, Antonio; Giampà, Carmela; Chiasserini, Davide; Tozzi, Alessandro; Orvietani, Pier Luigi; Ghiglieri, Veronica; Tantucci, Michela; Durante, Valentina; Quiroga-Varela, Ana; Mancini, Andrea; Costa, Cinzia; Sarchielli, Paola; Fusco, Francesca Romana; Calabresi, Paolo

    2016-01-01

    Cognitive impairment is common in multiple sclerosis (MS). Unfortunately, the synaptic and molecular mechanisms underlying MS-associated cognitive dysfunction are largely unknown. We explored the presence and the underlying mechanism of cognitive and synaptic hippocampal dysfunction during the remission phase of experimental MS. Experiments were performed in a chronic-relapsing experimental autoimmune encephalomyelitis (EAE) model of MS, after the resolution of motor deficits. Immunohistochemistry and patch-clamp recordings were performed in the CA1 hippocampal area. The hole-board was utilized as cognitive/behavioural test. In the remission phase of experimental MS, hippocampal microglial cells showed signs of activation, CA1 hippocampal synapses presented an impaired long-term potentiation (LTP) and an alteration of spatial tests became evident. The activation of hippocampal microglia mediated synaptic and cognitive/behavioural alterations during EAE. Specifically, LTP blockade was found to be caused by the reactive oxygen species (ROS)-producing enzyme nicotinamide adenine dinucleotide phosphate (NADPH) oxidase. We suggest that in the remission phase of experimental MS microglia remains activated, causing synaptic dysfunctions mediated by NADPH oxidase. Inhibition of microglial activation and NADPH oxidase may represent a promising strategy to prevent neuroplasticity impairment associated with active neuro-inflammation, with the aim to improve cognition and counteract MS disease progression. PMID:26887636

  7. AT₁ receptor and NAD(P)H oxidase mediate angiotensin II-stimulated antioxidant enzymes and mitogen-activated protein kinase activity in the rat hypothalamus.

    PubMed

    Silva, José; Pastorello, Mariella; Arzola, Jorge; Zavala, Lida E; De Jesús, Sara; Varela, Maider; Matos, María Gabriela; del Rosario Garrido, María; Israel, Anita

    2010-12-01

    Angiotensin II (AngII) regulates blood pressure and water and electrolyte metabolism through the stimulation of NAD(P)H oxidase and production of reactive oxygen species (ROS) such as O₂⁻, which is metabolised by superoxide dismutase, catalase and glutathione peroxidase. We assessed the role of AT₁ and AT₂ receptors, NAD(P)H oxidase and protein kinase C (PKC) in Ang II-induced sodium and water excretion and their capacity to stimulate antioxidant enzymes in the rat hypothalamus, a brain structure known to express a high density of AngII receptors. Male Sprague-Dawley rats were intracerebroventricularly (ICV) injected with AngII and urinary sodium and water excretion was assessed. Urine sodium concentration was determined using flame photometry. After decapitation the hypothalamus was microdissected under stereomicroscopic control. Superoxide dismutase, catalase and glutathione peroxidase activity were determined spectrophotometrically and extracellular signal-regulated kinase (ERK1/2) activation was analysed by Western blot. AngII-ICV resulted in antidiuresis and natriuresis. ICV administration of losartan, PD123319, apocynin and chelerythrine blunted natriuresis. In hypothalamus, AngII increased catalase, superoxide dismutase and glutation peroxidase activity and ERK1/2 phosphorylation. These actions were prevented by losartan, apocynin and chelerythrine, and increased by PD123319. AT₁ and AT₂ receptors, NAD(P)H oxidase and PKC pathway are involved in the regulation of hydromineral metabolism and antioxidant enzyme activity induced by AngII.

  8. Transcriptional regulation of NADPH oxidase isoforms, Nox1 and Nox4, by nuclear factor-{kappa}B in human aortic smooth muscle cells

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

    Manea, Adrian, E-mail: adrian.manea@icbp.ro; Tanase, Laurentia I.; Raicu, Monica

    Inflammation-induced changes in the activity and expression of NADPH oxidases (Nox) play a key role in atherogenesis. The molecular mechanisms of Nox regulation are scantily elucidated. Since nuclear factor-{kappa}B (NF-{kappa}B) controls the expression of many genes associated to inflammation-related diseases, in this study we have investigated the role of NF-{kappa}B signaling in the regulation of Nox1 and Nox4 transcription in human aortic smooth muscle cells (SMCs). Cultured cells were exposed to tumor necrosis factor-{alpha} (TNF{alpha}), a potent inducer of both Nox and NF-{kappa}B, up to 24 h. Lucigenin-enhanced chemiluminescence and dichlorofluorescein assays, real-time polymerase chain reaction, and Western blot analysismore » showed that inhibition of NF-{kappa}B pathway reduced significantly the TNF{alpha}-dependent up-regulation of Nox-derived reactive oxygen species production, Nox1 and Nox4 expression. In silico analysis indicated the existence of typical NF-{kappa}B elements in the promoters of Nox1 and Nox4. Transient overexpression of p65/NF-{kappa}B significantly increased the promoter activities of both isoforms. Physical interaction of p65/NF-{kappa}B proteins with the predicted sites was demonstrated by chromatin immunoprecipitation assay. These findings demonstrate that NF-{kappa}B is an essential regulator of Nox1- and Nox4-containing NADPH oxidase in SMCs. Elucidation of the complex relationships between NF-{kappa}B and Nox enzymes may lead to a novel pharmacological strategy to reduce both inflammation and oxidative stress in atherosclerosis and its associated complications.« less

  9. Involvement of NADPH oxidases in alkali burn-induced corneal injury.

    PubMed

    Gu, Xue-Jun; Liu, Xian; Chen, Ying-Ying; Zhao, Yao; Xu, Man; Han, Xiao-Jian; Liu, Qiu-Ping; Yi, Jing-Lin; Li, Jing-Ming

    2016-07-01

    Chemical burns are a major cause of corneal injury. Oxidative stress, inflammatory responses and neovascularization after the chemical burn aggravate corneal damage, and lead to loss of vision. Although NADPH oxidases (Noxs) play a crucial role in the production of reactive oxygen species (ROS), the role of Noxs in chemical burn-induced corneal injury remains to be elucidated. In the present study, the transcription and expression of Noxs in corneas were examined by RT-qPCR, western blot analysis and immunofluorescence staining. It was found that alkali burns markedly upregulated the transcription and expression of Nox2 and Nox4 in human or mouse corneas. The inhibition of Noxs by diphenyleneiodonium (DPI) or apocynin (Apo) effectively attenuated alkali burn-induced ROS production and decreased 3-nitrotyrosine (3-NT) protein levels in the corneas. In addition, Noxs/CD11b double‑immunofluorescence staining indicated that Nox2 and Nox4 were partially co-localized with CD11b. DPI or Apo prevented the infiltration of CD11b-positive inflammatory cells, and inhibited the transcription of inflammatory cytokines following alkali burn-induced corneal injury. In our mouse model of alkali burn-induced corneal injury, corneal neovascularization (CNV) occurred on day 3, and it affected 50% of the whole area of the cornea on day 7, and on day 14, CNV coverage of the cornea reached maximum levels. DPI or Apo effectively attenuated alkali burn‑induced CNV and decreased the mRNA levels of angiogenic factors, including vascular endothelial growth factor (VEGF), VEGF receptors and matrix metalloproteinases (MMPs). Taken together, our data indicate that Noxs play a role in alkali burn-induced corneal injury by regulating oxidative stress, inflammatory responses and CNV, and we thus suggest that Noxs are a potential therapeutic target in the future treatment of chemical-induced corneal injury.

  10. Oxygen-coupled redox regulation of the skeletal muscle ryanodine receptor-Ca2+ release channel by NADPH oxidase 4

    PubMed Central

    Sun, Qi-An; Hess, Douglas T.; Nogueira, Leonardo; Yong, Sandro; Bowles, Dawn E.; Eu, Jerry; Laurita, Kenneth R.; Meissner, Gerhard; Stamler, Jonathan S.

    2011-01-01

    Physiological sensing of O2 tension (partial O2 pressure, pO2) plays an important role in some mammalian cellular systems, but striated muscle generally is not considered to be among them. Here we describe a molecular mechanism in skeletal muscle that acutely couples changes in pO2 to altered calcium release through the ryanodine receptor–Ca2+-release channel (RyR1). Reactive oxygen species are generated in proportion to pO2 by NADPH oxidase 4 (Nox4) in the sarcoplasmic reticulum, and the consequent oxidation of a small set of RyR1 cysteine thiols results in increased RyR1 activity and Ca2+ release in isolated sarcoplasmic reticulum and in cultured myofibers and enhanced contractility of intact muscle. Thus, Nox4 is an O2 sensor in skeletal muscle, and O2-coupled hydrogen peroxide production by Nox4 governs the redox state of regulatory RyR1 thiols and thereby governs muscle performance. These findings reveal a molecular mechanism for O2-based signaling by an NADPH oxidase and demonstrate a physiological role for oxidative modification of RyR1. PMID:21896730

  11. Heme Oxygenase-1 Regulates Matrix Metalloproteinase MMP-1 Secretion and Chondrocyte Cell Death via Nox4 NADPH Oxidase Activity in Chondrocytes

    PubMed Central

    Rousset, Francis; Nguyen, Minh Vu Chuong; Grange, Laurent; Morel, Françoise; Lardy, Bernard

    2013-01-01

    Interleukin-1β (IL-1β) activates the production of reactive oxygen species (ROS) and secretion of MMPs as well as chondrocyte apoptosis. Those events lead to matrix breakdown and are key features of osteoarthritis (OA). We confirmed that in human C-20/A4 chondrocytes the NADPH oxidase Nox4 is the main source of ROS upon IL-1β stimulation. Since heme molecules are essential for the NADPH oxidase maturation and activity, we therefore investigated the consequences of the modulation of Heme oxygenase-1 (HO-1), the limiting enzyme in heme catabolism, on the IL-1β signaling pathway and more specifically on Nox4 activity. Induction of HO-1 expression decreased dramatically Nox4 activity in C-20/A4 and HEK293 T-REx™ Nox4 cell lines. Unexpectedly, this decrease was not accompanied by any change in the expression, the subcellular localization or the maturation of Nox4. In fact, the inhibition of the heme synthesis by succinylacetone rather than heme catabolism by HO-1, led to a confinement of the Nox4/p22phox heterodimer in the endoplasmic reticulum with an absence of redox differential spectrum highlighting an incomplete maturation. Therefore, the downregulation of Nox4 activity by HO-1 induction appeared to be mediated by carbon monoxide (CO) generated from the heme degradation process. Interestingly, either HO-1 or CO caused a significant decrease in the expression of MMP-1 and DNA fragmentation of chondrocytes stimulated by IL-1β. These results all together suggest that a modulation of Nox4 activity via heme oxygenase-1 may represent a promising therapeutic tool in osteoarthritis. PMID:23840483

  12. NADPH oxidase 4 attenuates cerebral artery changes during the progression of Marfan syndrome.

    PubMed

    Onetti, Yara; Meirelles, Thayna; Dantas, Ana P; Schröder, Katrin; Vila, Elisabet; Egea, Gustavo; Jiménez-Altayó, Francesc

    2016-05-01

    Marfan syndrome (MFS) is a connective tissue disorder that is often associated with the fibrillin-1 (Fbn1) gene mutation and characterized by cardiovascular alterations, predominantly ascending aortic aneurysms. Although neurovascular complications are uncommon in MFS, the improvement in Marfan patients' life expectancy is revealing other secondary alterations, potentially including neurovascular disorders. However, little is known about small-vessel pathophysiology in MFS. MFS is associated with hyperactivated transforming growth factor (TGF)-β signaling, which among numerous other downstream effectors, induces the NADPH oxidase 4 (Nox4) isoform of NADPH oxidase, a strong enzymatic source of H2O2 We hypothesized that MFS induces middle cerebral artery (MCA) alterations and that Nox4 contributes to them. MCA properties from 3-, 6-, or 9-mo-old Marfan (Fbn1(C1039G/+)) mice were compared with those from age/sex-matched wild-type littermates. At 6 mo, Marfan compared with wild-type mice developed higher MCA wall/lumen (wild-type: 0.081 ± 0.004; Marfan: 0.093 ± 0.002; 60 mmHg; P < 0.05), coupled with increased reactive oxygen species production, TGF-β, and Nox4 expression. However, wall stiffness and myogenic autoregulation did not change. To investigate the influence of Nox4 on cerebrovascular properties, we generated Marfan mice with Nox4 deficiency (Nox4(-/-)). Strikingly, Nox4 deletion in Marfan mice aggravated MCA wall thickening (cross-sectional area; Marfan: 6,660 ± 363 μm(2); Marfan Nox4(-/-): 8,795 ± 824 μm(2); 60 mmHg; P < 0.05), accompanied by decreased TGF-β expression and increased collagen deposition and Nox1 expression. These findings provide the first evidence that Nox4 mitigates cerebral artery structural changes in a murine model of MFS. Copyright © 2016 the American Physiological Society.

  13. Ethanol-induced erectile dysfunction and increased expression of pro-inflammatory proteins in the rat cavernosal smooth muscle are mediated by NADPH oxidase-derived reactive oxygen species.

    PubMed

    Leite, Letícia N; do Vale, Gabriel T; Simplicio, Janaina A; De Martinis, Bruno S; Carneiro, Fernando S; Tirapelli, Carlos R

    2017-06-05

    Ethanol consumption is associated with an increased risk of erectile dysfunction (ED), but the molecular mechanisms through which ethanol causes ED remain elusive. Reactive oxygen species are described as mediators of ethanol-induced cell toxicity/damage in distinctive tissues. The enzyme NADPH oxidase is the main source of reactive oxygen species in the endothelium and vascular smooth muscle cells and ethanol is described to increase NADPH oxidase activation and reactive oxygen species generation. This study evaluated the contribution of NADPH oxidase-derived reactive oxygen species to ethanol-induced ED, endothelial dysfunction and production of pro-inflammatory and redox-sensitive proteins in the rat cavernosal smooth muscle (CSM). Male Wistar rats were treated with ethanol (20% v/v) or ethanol plus apocynin (30mg/kg/day; p.o. gavage) for six weeks. Apocynin prevented both the decreased in acetylcholine-induced relaxation and intracavernosal pressure induced by ethanol. Ethanol increased superoxide anion (O 2 - ) generation and catalase activity in CSM, and treatment with apocynin prevented these responses. Similarly, apocynin prevented the ethanol-induced decreased of nitrate/nitrite (NOx), hydrogen peroxide (H 2 O 2 ) and SOD activity. Treatment with ethanol increased p47phox translocation to the membrane as well as the expression of Nox2, COX-1, catalase, iNOS, ICAM-1 and p65. Apocynin prevented the effects of ethanol on protein expression and p47phox translocation. Finally, treatment with ethanol increased both TNF-α production and neutrophil migration in CSM. The major new finding of this study is that NADPH oxidase-derived reactive oxygen species play a role on chronic ethanol consumption-induced ED and endothelial dysfunction in the rat CSM. Copyright © 2017 Elsevier B.V. All rights reserved.

  14. Nebivolol prevents ethanol-induced reactive oxygen species generation and lipoperoxidation in the rat kidney by regulating NADPH oxidase activation and expression.

    PubMed

    do Vale, Gabriel T; Gonzaga, Natália A; Simplicio, Janaina A; Tirapelli, Carlos R

    2017-03-15

    We studied whether the β 1 -adrenergic antagonist nebivolol would prevent ethanol-induced reactive oxygen species generation and lipoperoxidation in the rat renal cortex. Male Wistar rats were treated with ethanol (20% v/v) for 2 weeks. Nebivolol (10mg/kg/day; p.o. gavage) prevented both the increase in superoxide anion (O 2 - ) generation and thiobarbituric acid reactive substances (TBARS) concentration induced by ethanol in the renal cortex. Ethanol decreased nitrate/nitrite (NOx) concentration in the renal cortex, and nebivolol prevented this response. Nebivolol did not affect the reduction of hydrogen peroxide (H 2 O 2 ) concentration induced by ethanol. Nebivolol prevented the ethanol-induced increase of catalase (CAT) activity. Both SOD activity and the levels of reduced glutathione (GSH) were not affected by treatment with nebivolol or ethanol. Neither ethanol nor nebivolol affected the expression of Nox1, Nox4, eNOS, nNOS, CAT, Nox organizer 1 (Noxo1), c-Src, p47 phox or superoxide dismutase (SOD) isoforms in the renal cortex. On the other hand, treatment with ethanol increased Nox2 expression, and nebivolol prevented this response. Finally, nebivolol reduced the expression of protein kinase (PK) Cδ and Rac1. The major finding of our study is that nebivolol prevented ethanol-induced reactive oxygen species generation and lipoperoxidation in the kidney by a mechanism that involves reduction on the expression of Nox2, a catalytic subunit of NADPH oxidase. Additionally, we demonstrated that nebivolol reduces NADPH oxidase-derived reactive oxygen species by decreasing the expression of PKCδ and Rac1, which are important activators of NADPH oxidase. Copyright © 2017 Elsevier B.V. All rights reserved.

  15. Rotenone Activates Phagocyte NADPH Oxidase through Binding to Its Membrane Subunit gp91phox

    PubMed Central

    Zhou, Hui; Zhang, Feng; Chen, Shih-heng; Zhang, Dan; Wilson, Belinda; Hong, Jau-shyong; Gao, Hui-Ming

    2011-01-01

    Rotenone, a widely used pesticide, reproduces Parkinsonism in rodents and associates with increased risk for Parkinson’s disease. We previously reported rotenone increased superoxide production through stimulating microglial phagocyte NADPH oxidase (PHOX). The present study identified a novel mechanism by which rotenone activates PHOX. Ligand-binding assay revealed that rotenone directly bound to membrane gp91phox, the catalytic subunit of PHOX; such binding was inhibited by diphenyleneiodonium, a PHOX inhibitor with a binding site on gp91phox. Functional studies showed both membrane and cytosolic subunits were required for rotenone-induced superoxide production in cell-free systems, intact phagocytes, and COS7 cells transfected with membrane subunits (gp91phox/p22phox) and cytosolic subunits (p67phox and p47phox). Rotenone-elicited extracellular superoxide release in p47phox-deficient macrophages suggested rotenone enabled to activate PHOX through a p47phox-independent mechanism. Increased membrane translocation of p67phox, elevated binding of p67phox to rotenone-treated membrane fractions, and co-immunoprecipitation of p67phox and gp91phox in rotenone-treated wild-type and p47phox-deficient macrophages indicated p67phox played a critical role in rotenone-induced PHOX activation via its direct interaction with gp91phox. Rac1, a Rho-like small GTPase, enhanced p67phox-gp91phox interaction; Rac1 inhibition decreased rotenone-elicited superoxide release. In conclusion, rotenone directly interacted with gp91phox; such an interaction triggered membrane translocation of p67phox, leading to PHOX activation and superoxide production. PMID:22094225

  16. Associations Between Genetic Variants of NADPH Oxidase-Related Genes and Blood Pressure Responses to Dietary Sodium Intervention: The GenSalt Study.

    PubMed

    Han, Xikun; Hu, Zunsong; Chen, Jing; Huang, Jianfeng; Huang, Chen; Liu, Fangchao; Gu, Charles; Yang, Xueli; Hixson, James E; Lu, Xiangfeng; Wang, Laiyuan; Liu, De-Pei; He, Jiang; Chen, Shufeng; Gu, Dongfeng

    2017-04-01

    The aim of this study was to comprehensively test the associations of genetic variants of nicotinamide adenine dinucleotide phosphate (NADPH) oxidase-related genes with blood pressure (BP) responses to dietary sodium intervention in a Chinese population. We conducted a 7-day low-sodium intervention followed by a 7-day high-sodium intervention among 1,906 participants in rural China. BP measurements were obtained at baseline and each dietary intervention using a random-zero sphygmomanometer. Linear mixed-effect models were used to assess the additive associations of 63 tag single-nucleotide polymorphisms in 11 NADPH oxidase-related genes with BP responses to dietary sodium intervention. Gene-based analyses were conducted using the truncated product method. The Bonferroni method was used to adjust for multiple testing in all analyses. Systolic BP (SBP) response to high-sodium intervention significantly decreased with the number of minor T allele of marker rs6967221 in RAC1 (P = 4.51 × 10-4). SBP responses (95% confidence interval) for genotypes CC, CT, and TT were 5.03 (4.71, 5.36), 4.20 (3.54, 4.85), and 0.56 (-1.08, 2.20) mm Hg, respectively, during the high-sodium intervention. Gene-based analyses revealed that RAC1 was significantly associated with SBP response to high-sodium intervention (P = 1.00 × 10-6) and diastolic BP response to low-sodium intervention (P = 9.80 × 10-4). These findings suggested that genetic variants of NADPH oxidase-related genes may contribute to the variation of BP responses to sodium intervention in Chinese population. Further replication of these findings is warranted. © American Journal of Hypertension, Ltd 2017. All rights reserved. For Permissions, please email: journals.permissions@oup.com

  17. On the use of L-012, a luminol-based chemiluminescent probe, for detecting superoxide and identifying inhibitors of NADPH oxidase: A re-evaluation

    PubMed Central

    Zielonka, Jacek; Lambeth, J. David; Kalyanaraman, Balaraman

    2014-01-01

    L-012, a luminol-based chemiluminescent (CL) probe, is widely used in vitro and in vivo to detect NADPH oxidase (Nox)-derived superoxide (O2·−) and identify Nox inhibitors. Yet understanding of the free radical chemistry of L-012 probe is still lacking. We report that peroxidase and H2O2 induce superoxide dismutase (SOD)-sensitive, L-012-derived CL in the presence of oxygen. O2·− alone does not react with L-012 to emit luminescence. Self-generated O2·− during oxidation of L-012 and luminol-analogs artifactually induce CL inhibitable by SOD. These aspects make assays based on luminol analogs less than ideal for specific detection and identification of O2·− and NOX inhibitors. PMID:24080119

  18. Early NADPH oxidase-2 activation is crucial in phenylephrine-induced hypertrophy of H9c2 cells.

    PubMed

    Hahn, Nynke E; Musters, René J P; Fritz, Jan M; Pagano, Patrick J; Vonk, Alexander B A; Paulus, Walter J; van Rossum, Albert C; Meischl, Christof; Niessen, Hans W M; Krijnen, Paul A J

    2014-09-01

    Reactive oxygen species (ROS) produced by different NADPH oxidases (NOX) play a role in cardiomyocyte hypertrophy induced by different stimuli, such as angiotensin II and pressure overload. However, the role of the specific NOX isoforms in phenylephrine (PE)-induced cardiomyocyte hypertrophy is unknown. Therefore we aimed to determine the involvement of the NOX isoforms NOX1, NOX2 and NOX4 in PE-induced cardiomyocyte hypertrophy. Hereto rat neonatal cardiomyoblasts (H9c2 cells) were incubated with 100 μM PE to induce hypertrophy after 24 and 48h as determined via cell and nuclear size measurements using digital imaging microscopy, electron microscopy and an automated cell counter. Digital-imaging microscopy further revealed that in contrast to NOX1 and NOX4, NOX2 expression increased significantly up to 4h after PE stimulation, coinciding and co-localizing with ROS production in the cytoplasm as well as the nucleus. Furthermore, inhibition of NOX-mediated ROS production with apocynin, diphenylene iodonium (DPI) or NOX2 docking sequence (Nox2ds)-tat peptide during these first 4h of PE stimulation significantly inhibited PE-induced hypertrophy of H9c2 cells, both after 24 and 48h of PE stimulation. These data show that early NOX2-mediated ROS production is crucial in PE-induced hypertrophy of H9c2 cells. Copyright © 2014 Elsevier Inc. All rights reserved.

  19. NADPH oxidases differentially regulate ROS metabolism and nutrient uptake under cadmium toxicity.

    PubMed

    Gupta, D K; Pena, L B; Romero-Puertas, M C; Hernández, A; Inouhe, M; Sandalio, L M

    2017-04-01

    The role of NADPH oxidases under cadmium (Cd) toxicity was studied using Arabidopsis thaliana mutants AtrbohC, AtrbohD and AtrbohF, which were grown under hydroponic conditions with 25 and 100 μM Cd for 1 and 5 days. Cadmium reduced the growth of leaves in WT, AtrbohC and D, but not in AtrbohF. A time-dependent increase in H 2 O 2 and lipid peroxidation was observed in all genotypes, with AtrbohC showing the smallest increase. An opposite behaviour was observed with NO accumulation. Cadmium increased catalase activity in WT plants and decreased it in Atrboh mutants, while glutathione reductase and glycolate oxidase activities increased in Atrboh mutants, and superoxide dismutases were down-regulated in AtrbohC. The GSH/GSSG and ASA/DHA couples were also affected by the treatment, principally in AtrbohC and AtrbohF, respectively. Cadmium translocation to the leaves was severely reduced in Atrboh mutants after 1 day of treatment and even after 5 days in AtrbohF. Similar results were observed for S, P, Ca, Zn and Fe accumulation, while an opposite trend was observed for K accumulation, except in AtrbohF. Thus, under Cd stress, RBOHs differentially regulate ROS metabolism, redox homeostasis and nutrient balance and could be of potential interest in biotechnology for the phytoremediation of polluted soils. © 2016 John Wiley & Sons Ltd.

  20. Granzyme B of cytotoxic T cells induces extramitochondrial reactive oxygen species production via caspase-dependent NADPH oxidase activation.

    PubMed

    Aguiló, Juan I; Anel, Alberto; Catalán, Elena; Sebastián, Alvaro; Acín-Pérez, Rebeca; Naval, Javier; Wallich, Reinhard; Simon, Markus M; Pardo, Julián

    2010-07-01

    Induction of reactive oxygen species (ROS) is a hallmark of granzyme B (gzmB)-mediated pro-apoptotic processes and target cell death. However, it is unclear to what extent the generated ROS derive from mitochondrial and/or extra-mitochondrial sources. To clarify this point, we have produced a mutant EL4 cell line, termed EL4-rho(0), which lacks mitochondrial DNA, associated with a decreased mitochondrial membrane potential and a defective ROS production through the electron transport chain of oxidative phosphorylation. When incubated with either recombinant gzmB plus streptolysin or ex vivo gzmB(+) cytotoxic T cells, EL4-rho(0) cells showed phosphatydylserine translocation, caspase 3 activation, Bak conformational change, cytochrome c release and apoptotic morphology comparable to EL4 cells. Moreover, EL4-rho(0) cells produced ROS at levels similar to EL4 under these conditions. GzmB-mediated ROS production was almost totally abolished in both cell lines by the pan-caspase inhibitor, Z-VAD-fmk. However, addition of apocynin, a specific inhibitor of nicotinamide adenine dinucleotide phosphate (NADPH) oxidases, led to a significant reduction of ROS production and cell death only in EL4-rho(0) but not EL4 cells. These data suggest that gzmB-induced cell death is accompanied by a caspase-dependent pathway of extra-mitochondrial ROS production, most probably through activation of NADPH oxidase.

  1. The NADPH oxidase inhibitor apocynin (acetovanillone) induces oxidative stress

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

    Riganti, Chiara; Costamagna, Costanzo; Bosia, Amalia

    Apocynin (acetovanillone) is often used as a specific inhibitor of NADPH oxidase. In N11 glial cells, apocynin induced, in a dose-dependent way, a significant increase of both malonyldialdehyde level (index of lipid peroxidation) and lactate dehydrogenase release (index of a cytotoxic effect). Apocynin evoked also, in a significant way, an increase of H{sub 2}O{sub 2} concentration and a decrease of the intracellular glutathione/glutathione disulfide ratio, accompanied by augmented efflux of glutathione and glutathione disulfide. Apocynin induced the activation of both pentose phosphate pathway and tricarboxylic acid cycle, which was blocked when the cells were incubated with glutathione together with apocynin.more » The cell incubation with glutathione prevented also the apocynin-induced increase of malonyldialdehyde generation and lactate dehydrogenase leakage. Apocynin exerted an oxidant effect also in a cell-free system: indeed, in aqueous solution, it evoked a faster oxidation of the thiols glutathione and dithiothreitol, and elicited the generation of reactive oxygen species, mainly superoxide anions. Our results suggest that apocynin per se can induce an oxidative stress and exert a cytotoxic effect in N11 cells and other cell types, and that some effects of apocynin in in vitro and in vivo experimental models should be interpreted with caution.« less

  2. Thermodynamic and NMR analyses of NADPH binding to lipocalin-type prostaglandin D synthase

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

    Qin, Shubin; Shimamoto, Shigeru; Maruno, Takahiro

    2015-12-04

    Lipocalin-type prostaglandin D synthase (L-PGDS) is one of the most abundant proteins in human cerebrospinal fluid (CSF) with dual functions as a prostaglandin D{sub 2} (PGD{sub 2}) synthase and a transporter of lipophilic ligands. Recent studies revealed that L-PGDS plays important roles in protecting against various neuronal diseases induced by reactive oxygen species (ROS). However, the molecular mechanisms of such protective actions of L-PGDS remain unknown. In this study, we conducted thermodynamic and nuclear magnetic resonance (NMR) analyses, and demonstrated that L-PGDS binds to nicotinamide coenzymes, including NADPH, NADP{sup +}, and NADH. Although a hydrophilic ligand is not common formore » L-PGDS, these ligands, especially NADPH showed specific interaction with L-PGDS at the upper pocket of its ligand-binding cavity with an unusually bifurcated shape. The binding affinity of L-PGDS for NADPH was comparable to that previously reported for NADPH oxidases and NADPH in vitro. These results suggested that L-PGDS potentially attenuates the activities of NADPH oxidases through interaction with NADPH. Given that NADPH is the substrate for NADPH oxidases that play key roles in neuronal cell death by generating excessive ROS, these results imply a novel linkage between L-PGDS and ROS. - Highlights: • Interactions of L-PGDS with nicotinamide coenzymes were studied by ITC and NMR. • The binding affinity of L-PGDS was strongest to NADPH among nicotinamide coenzymes. • NADPH binds to the upper part of L-PGDS ligand-binding cavity. • L-PGDS binds to both lipophilic and hydrophilic ligands. • This study implies a novel linkage between L-PGDS and reactive oxygen species.« less

  3. Erythrocyte NADPH oxidase activity modulated by Rac GTPases, PKC, and plasma cytokines contributes to oxidative stress in sickle cell disease

    PubMed Central

    Pushkaran, Suvarnamala; Konstantinidis, Diamantis G.; Koochaki, Sebastian; Malik, Punam; Mohandas, Narla; Zheng, Yi; Joiner, Clinton H.; Kalfa, Theodosia A.

    2013-01-01

    Chronic inflammation has emerged as an important pathogenic mechanism in sickle cell disease (SCD). One component of this inflammatory response is oxidant stress mediated by reactive oxygen species (ROS) generated by leukocytes, endothelial cells, plasma enzymes, and sickle red blood cells (RBC). Sickle RBC ROS generation has been attributed to sickle hemoglobin auto-oxidation and Fenton chemistry reactions catalyzed by denatured heme moieties bound to the RBC membrane. In this study, we demonstrate that a significant part of ROS production in sickle cells is mediated enzymatically by NADPH oxidase, which is regulated by protein kinase C, Rac GTPase, and intracellular Ca2+ signaling within the sickle RBC. Moreover, plasma from patients with SCD and isolated cytokines, such as transforming growth factor β1 and endothelin-1, enhance RBC NADPH oxidase activity and increase ROS generation. ROS-mediated damage to RBC membrane components is known to contribute to erythrocyte rigidity and fragility in SCD. Erythrocyte ROS generation, hemolysis, vaso-occlusion, and the inflammatory response to tissue damage may therefore act in a positive-feedback loop to drive the pathophysiology of sickle cell disease. These findings suggest a novel pathogenic mechanism in SCD and may offer new therapeutic targets to counteract inflammation and RBC rigidity and fragility in SCD. PMID:23349388

  4. Reactive oxygen species derived from NAD(P)H oxidase play a role on ethanol-induced hypertension and endothelial dysfunction in rat resistance arteries.

    PubMed

    Simplicio, Janaina A; do Vale, Gabriel T; Gonzaga, Natália A; Leite, Letícia N; Hipólito, Ulisses V; Pereira, Camila A; Tostes, Rita C; Tirapelli, Carlos R

    2017-02-01

    Chronic ethanol consumption is a risk factor for cardiovascular diseases. We studied whether NAD(P)H oxidase-derived reactive oxygen species (ROS) play a role in ethanol-induced hypertension, vascular dysfunction, and protein expression in resistance arteries. Male Wistar rats were treated with ethanol (20 % v/v) for 6 weeks. Ethanol treatment increased blood pressure and decreased acetylcholine-induced relaxation in the rat mesenteric arterial bed (MAB). These responses were attenuated by apocynin (30 mg/kg/day; p.o. gavage). Ethanol consumption increased superoxide anion (O 2 - ) generation and decreased nitrate/nitrite (NO x ) concentration in the rat MAB and apocynin prevented these responses. Conversely, ethanol did not affect the concentration of hydrogen peroxide (H 2 O 2 ) and reduced glutathione (GSH) or the activity of superoxide dismutase (SOD) and catalase (CAT) in the rat MAB. Ethanol increased interleukin (IL)-10 levels in the rat MAB but did not affect the levels of tumor necrosis factor (TNF)-α, IL-6, or IL-1β. Ethanol increased the expression of Nox2 and the phosphorylation of SAPK/JNK, but reduced eNOS expression in the rat MAB. Apocynin prevented these responses. However, ethanol treatment did not affect the expression of Nox1, Nox4, p38MAPK, ERK1/2, or SAPK/JNK in the rat MAB. Ethanol increased plasma levels of TBARS, TNF-α, IL-6, IL-1β, and IL-10, whereas it decreased NO x levels. The major finding of our study is that NAD(P)H oxidase-derived ROS play a role on ethanol-induced hypertension and endothelial dysfunction in resistance arteries. Moreover, ethanol consumption affects the expression and phosphorylation of proteins that regulate vascular function and NAD(P)H oxidase-derived ROS play a role in such responses.

  5. EPA:DHA 6:1 prevents angiotensin II-induced hypertension and endothelial dysfunction in rats: role of NADPH oxidase- and COX-derived oxidative stress.

    PubMed

    Niazi, Zahid Rasul; Silva, Grazielle C; Ribeiro, Thais Porto; León-González, Antonio J; Kassem, Mohamad; Mirajkar, Abdur; Alvi, Azhar; Abbas, Malak; Zgheel, Faraj; Schini-Kerth, Valérie B; Auger, Cyril

    2017-12-01

    Eicosapentaenoic acid:docosahexaenoic acid (EPA:DHA) 6:1, an omega-3 polyunsaturated fatty acid formulation, has been shown to induce a sustained formation of endothelial nitric oxide (NO) synthase-derived NO, a major vasoprotective factor. This study examined whether chronic intake of EPA:DHA 6:1 prevents hypertension and endothelial dysfunction induced by angiotensin II (Ang II) in rats. Male Wister rats received orally corn oil or EPA:DHA 6:1 (500 mg kg -1 per day) before chronic infusion of Ang II (0.4 mg kg -1 per day). Systolic blood pressure was determined by tail cuff sphingomanometry, vascular reactivity using a myograph, oxidative stress using dihydroethidium and protein expression by immunofluorescence and western blot analysis. Ang II-induced hypertension was associated with reduced acetylcholine-induced relaxations of secondary branch mesenteric artery rings affecting the endothelium-dependent hyperpolarization (EDH)- and the NO-mediated relaxations, both of which were improved by the NADPH oxidase inhibitor VAS-2870. The Ang II treatment induced also endothelium-dependent contractile responses (EDCFs), which were abolished by the cyclooxygenase (COX) inhibitor indomethacin. An increased level of vascular oxidative stress and expression of NADPH oxidase subunits (p47 phox and p22 phox ), COX-1 and COX-2, endothelial NO synthase and Ang II type 1 receptors were observed in the Ang II group, whereas SK Ca and connexin 37 were downregulated. Intake of EPA:DHA 6:1 prevented the Ang II-induced hypertension and endothelial dysfunction by improving both the NO- and EDH-mediated relaxations, and by reducing EDCFs and the expression of target proteins. The present findings indicate that chronic intake of EPA:DHA 6:1 prevented the Ang II-induced hypertension and endothelial dysfunction in rats, most likely by preventing NADPH oxidase- and COX-derived oxidative stress.

  6. Dextromethorphan inhibition of voltage-gated proton currents in BV2 microglial cells.

    PubMed

    Song, Jin-Ho; Yeh, Jay Z

    2012-05-10

    Dextromethorphan, an antitussive drug, has a neuroprotective property as evidenced by its inhibition of microglial production of pro-inflammatory cytokines and reactive oxygen species. The microglial activation requires NADPH oxidase activity, which is sustained by voltage-gated proton channels in microglia as they dissipate an intracellular acid buildup. In the present study, we examined the effect of dextromethorphan on proton currents in microglial BV2 cells. Dextromethorphan reversibly inhibited proton currents with an IC(50) value of 51.7 μM at an intracellular/extracellular pH gradient of 5.5/7.3. Dextromethorphan did not change the reversal potential or the voltage dependence of the gating. Dextrorphan and 3-hydroxymorphinan, major metabolites of dextromethorphan, and dextromethorphan methiodide were ineffective in inhibiting proton currents. The results indicate that dextromethorphan inhibition of proton currents would suppress NADPH oxidase activity and, eventually, microglial activation. Copyright © 2012 Elsevier Ireland Ltd. All rights reserved.

  7. Exercise training protects against atherosclerotic risk factors through vascular NADPH oxidase, extracellular signal-regulated kinase 1/2 and stress-activated protein kinase/c-Jun N-terminal kinase downregulation in obese rats.

    PubMed

    Touati, Sabeur; Montezano, Augusto C I; Meziri, Fayçal; Riva, Catherine; Touyz, Rhian M; Laurant, Pascal

    2015-02-01

    Exercise training reverses atherosclerotic risk factors associated with metabolic syndrome and obesity. The aim of the present study was to determine the molecular anti-inflammatory, anti-oxidative and anti-atherogenic effects in aorta from rats with high-fat diet-induced obesity. Male Sprague-Dawley rats were placed on a high-fat (HFD) or control (CD) diet for 12 weeks. The HFD rats were then divided into four groups: (i) sedentary HFD-fed rats (HFD-S); (ii) exercise trained (motor treadmill 5 days/week, 60 min/day, 12 weeks) HFD-fed rats (HFD-Ex); (iii) modified diet (HFD to CD) sedentary rats (HF/CD-S); and (iv) an exercise-trained modified diet group (HF/CD-Ex). Tissue levels of NADPH oxidase (activity and expression), NADPH oxidase (Nox) 1, Nox2, Nox4, p47(phox) , superoxide dismutase (SOD)-1, angiotensin AT1 and AT2 receptors, phosphorylated mitogen-activated protein kinase (MAPK; extracellular signal-regulated kinase (ERK) 1/2, stress-activated protein kinase (SAPK)/c-Jun N-terminal kinase (JNK)) and vascular cell adhesion molecule-1 (VCAM-1) were determined in the aorta. Plasma cytokines (tumour necrosis factor (TNF)-α and interleukin (IL)-6) levels were also measured. Obesity was accompanied by increases in NADPH oxidase activity, p47(phox) translocation, Nox4 and VCAM-1 protein expression, MAPK (ERK1/2, SAPK/JNK) phosphorylation and plasma TNF-α and IL-6 levels. Exercise training and switching from the HFD to CD reversed almost all these molecular changes. In addition, training increased aortic SOD-1 protein expression and decreased ERK1/2 phosphorylation. These findings suggest that protective effects of exercise training on atherosclerotic risk factors induced by obesity are associated with downregulation of NADPH oxidase, ERK1/2 and SAPK/JNK activity and increased SOD-1 expression. © 2014 Wiley Publishing Asia Pty Ltd.

  8. Staphylococcus aureus, phagocyte NADPH oxidase and chronic granulomatous disease.

    PubMed

    Buvelot, Helene; Posfay-Barbe, Klara M; Linder, Patrick; Schrenzel, Jacques; Krause, Karl-Heinz

    2017-03-01

    Dysfunction of phagocytes is a relevant risk factor for staphylococcal infection. The most common hereditary phagocyte dysfunction is chronic granulomatous disease (CGD), characterized by impaired generation of reactive oxygen species (ROS) due to loss of function mutations within the phagocyte NADPH oxidase NOX2. Phagocytes ROS generation is fundamental to eliminate pathogens and to regulate the inflammatory response to infection. CGD is characterized by recurrent and severe bacterial and fungal infections, with Staphylococcus aureus as the most frequent pathogen, and skin and lung abscesses as the most common clinical entities. Staphylococcus aureus infection may occur in virtually any human host, presumably because of the many virulence factors of the bacterium. However, in the presence of functional NOX2, staphylococcal infections remain rare and are mainly linked to breaches of the skin barrier. In contrast, in patients with CGD, S. aureus readily survives and frequently causes clinically apparent disease. Astonishingly, little is known why S. aureus, which possesses a wide range of antioxidant enzymes (e.g. catalase, SOD), is particularly sensitive to control through NOX2. In this review, we will evaluate the discovery of CGD and our present knowledge of the role of NOX2 in S. aureus infection. © FEMS 2016. All rights reserved. For permissions, please e-mail: journals.permissions@oup.com.

  9. Allelic variations in the CYBA gene of NADPH oxidase and risk of kidney complications in patients with type 1 diabetes.

    PubMed

    Patente, Thiago A; Mohammedi, Kamel; Bellili-Muñoz, Naïma; Driss, Fathi; Sanchez, Manuel; Fumeron, Frédéric; Roussel, Ronan; Hadjadj, Samy; Corrêa-Giannella, Maria Lúcia; Marre, Michel; Velho, Gilberto

    2015-09-01

    Oxidative stress plays a pivotal role in the pathophysiology of diabetic nephropathy, and the nicotinamide adenine dinucleotide phosphate (NADPH) oxidase system is an important source of reactive oxygen species in hyperglycemic conditions in the kidney. Plasma concentration of advanced oxidation protein products (AOPP), a marker of oxidative stress, is increased in patients with diabetic nephropathy. We investigated associations of variants in the CYBA gene, encoding the regulatory subunit p22(phox) of NADPH oxidase, with diabetic nephropathy and plasma AOPP and myeloperoxidase (MPO) concentrations in type 1 diabetic patients. Seven SNPs in the CYBA region were analyzed in 1357 Caucasian subjects with type 1 diabetes from the SURGENE (n=340), GENEDIAB (n=444), and GENESIS (n=573) cohorts. Duration of follow-up was 10, 9, and 6 years, respectively. Cox proportional hazards and logistic regression analyses were used to estimate hazard ratios (HR) or odds ratios (OR) for incidence and prevalence of diabetic nephropathy. The major G-allele of rs9932581 was associated with the incidence of renal events defined as new cases of microalbuminuria or the progression to a more severe stage of nephropathy during follow-up (HR 1.59, 95% CI 1.17-2.18, P=0.003) in SURGENE. The same allele was associated with established/advanced nephropathy (OR 1.52, 95% CI 1.22-1.92, P=0.0001) and with the incidence of end-stage renal disease (ESRD) (HR 2.01, 95% CI 1.30-3.24, P=0.001) in GENEDIAB/GENESIS pooled studies. The risk allele was also associated with higher plasma AOPP concentration in subsets of SURGENE and GENEDIAB, with higher plasma MPO concentration in a subset of GENEDIAB, and with lower estimated glomerular filtration rate (eGFR) in the three cohorts. In conclusion, a functional variant in the promoter of the CYBA gene was associated with lower eGFR and with prevalence and incidence of diabetic nephropathy and ESRD in type 1 diabetic patients. These results are consistent with

  10. Prolonged exposure of cortical neurons to oligomeric amyloid-β impairs NMDA receptor function via NADPH oxidase-mediated ROS production: protective effect of green tea (–)-epigallocatechin-3-gallate

    PubMed Central

    He, Yan; Cui, Jiankun; Lee, James C-M; Ding, Shinghua; Chalimoniuk, Malgorzata; Simonyi, Agnes; Sun, Albert Y; Gu, Zezong; Weisman∥, Gary A; Gibson Wood, W; Sun, Grace Y

    2011-01-01

    Excessive production of Aβ (amyloid β-peptide) has been shown to play an important role in the pathogenesis of AD (Alzheimer's disease). Although not yet well understood, aggregation of Aβ is known to cause toxicity to neurons. Our recent study demonstrated the ability for oligomeric Aβ to stimulate the production of ROS (reactive oxygen species) in neurons through an NMDA (N-methyl-d-aspartate)-dependent pathway. However, whether prolonged exposure of neurons to aggregated Aβ is associated with impairment of NMDA receptor function has not been extensively investigated. In the present study, we show that prolonged exposure of primary cortical neurons to Aβ oligomers caused mitochondrial dysfunction, an attenuation of NMDA receptor-mediated Ca2+ influx and inhibition of NMDA-induced AA (arachidonic acid) release. Mitochondrial dysfunction and the decrease in NMDA receptor activity due to oligomeric Aβ are associated with an increase in ROS production. Gp91ds-tat, a specific peptide inhibitor of NADPH oxidase, and Mn(III)-tetrakis(4-benzoic acid)-porphyrin chloride, an ROS scavenger, effectively abrogated Aβ-induced ROS production. Furthermore, Aβ-induced mitochondrial dysfunction, impairment of NMDA Ca2+ influx and ROS production were prevented by pre-treatment of neurons with EGCG [(−)-epigallocatechin-3-gallate], a major polyphenolic component of green tea. Taken together, these results support a role for NADPH oxidase-mediated ROS production in the cytotoxic effects of Aβ, and demonstrate the therapeutic potential of EGCG and other dietary polyphenols in delaying onset or retarding the progression of AD. PMID:21434871

  11. Indonesian herbal medicine prevents hypertension-induced left ventricular hypertrophy by diminishing NADPH oxidase-dependent oxidative stress.

    PubMed

    Sulistyowati, Erna; Hsu, Jong-Hau; Cheng, Yuan-Bin; Chang, Fang-Rong; Chen, Ying-Fu; Yeh, Jwu-Lai

    2017-10-17

    Indonesian herbal medicine Centella asiatica , Justicia gendarussa and Imperata cylindrica decoction (CJID) are known to be efficacious for hypertension. Oxidative stress plays an important role in hypertension-induced left ventricular hypertrophy (H-LVH). This study evaluated whether CJID inhibit cardiac remodeling in spontaneously hypertensive rats (SHRs) through mechanism of oxidative stress-related cardiac-NADPH oxidase (NOXs) pathway: NOX1, NOX2 and NOX4. Forty-weeks-old SHRs and normotensive-WKY rats, were both randomly divided into 2 groups: CJID and control. All rats were treated for 5 weeks. Systolic blood pressure (SBP) and heart rate (HR) were measured. LV morphology, function and performance were assessed by histological staining and echocardiography. Serum and cardiac superoxide dismutase (SOD) activity and malondialdehyde (MDA) content were assessed. Cardiac superoxide and hydrogen peroxide (H 2 O 2 ) productions, protein expressions of SOD2, SOD3, NOX1, NOX2 and NOX4 were also determined. We found that SBP and HR were significantly decreased in SHRs-treated group. Echocardiography showed that CJID significantly improved LV morphometry and function. CJID decreased MDA level, but increased SOD activity. Cardiac superoxide and H 2 O 2 generation were decreased in SHRs-treated group. CJID caused cardiac SODs expressions to be increased but NOXs expressions to be suppressed. In conclusion, CJID prevents H-LVH by reducing reactive oxygen species production via the NOXs-dependent pathway.

  12. Indonesian herbal medicine prevents hypertension-induced left ventricular hypertrophy by diminishing NADPH oxidase-dependent oxidative stress

    PubMed Central

    Sulistyowati, Erna; Hsu, Jong-Hau; Cheng, Yuan-Bin; Chang, Fang-Rong; Chen, Ying-Fu; Yeh, Jwu-Lai

    2017-01-01

    Indonesian herbal medicine Centella asiatica, Justicia gendarussa and Imperata cylindrica decoction (CJID) are known to be efficacious for hypertension. Oxidative stress plays an important role in hypertension-induced left ventricular hypertrophy (H-LVH). This study evaluated whether CJID inhibit cardiac remodeling in spontaneously hypertensive rats (SHRs) through mechanism of oxidative stress-related cardiac-NADPH oxidase (NOXs) pathway: NOX1, NOX2 and NOX4. Forty-weeks-old SHRs and normotensive-WKY rats, were both randomly divided into 2 groups: CJID and control. All rats were treated for 5 weeks. Systolic blood pressure (SBP) and heart rate (HR) were measured. LV morphology, function and performance were assessed by histological staining and echocardiography. Serum and cardiac superoxide dismutase (SOD) activity and malondialdehyde (MDA) content were assessed. Cardiac superoxide and hydrogen peroxide (H2O2) productions, protein expressions of SOD2, SOD3, NOX1, NOX2 and NOX4 were also determined. We found that SBP and HR were significantly decreased in SHRs-treated group. Echocardiography showed that CJID significantly improved LV morphometry and function. CJID decreased MDA level, but increased SOD activity. Cardiac superoxide and H2O2 generation were decreased in SHRs-treated group. CJID caused cardiac SODs expressions to be increased but NOXs expressions to be suppressed. In conclusion, CJID prevents H-LVH by reducing reactive oxygen species production via the NOXs-dependent pathway. PMID:29156835

  13. NADPH oxidase-derived overproduction of reactive oxygen species impairs postischemic neovascularization in mice with type 1 diabetes.

    PubMed

    Ebrahimian, Téni G; Heymes, Christophe; You, Dong; Blanc-Brude, Olivier; Mees, Barend; Waeckel, Ludovic; Duriez, Micheline; Vilar, José; Brandes, Ralph P; Levy, Bernard I; Shah, Ajay M; Silvestre, Jean-Sébastien

    2006-08-01

    We hypothesized that diabetes-induced oxidative stress may affect postischemic neovascularization. The response to unilateral femoral artery ligation was studied in wild-type or gp91(phox)-deficient control or type 1 diabetic mice or in animals treated with the anti-oxidant N-acetyl-l-cysteine (NAC) or with in vivo electrotransfer of a plasmid encoding dominant-negative Rac1 (50 microg) for 21 days. Postischemic neovascularization was reduced in diabetic mice in association with down-regulated vascular endothelial growth factor-A protein levels. In diabetic animals vascular endothelial growth factor levels and postischemic neovascularization were restored to nondiabetic levels by the scavenging of reactive oxygen species (ROS) by NAC administration or the inhibition of ROS generation by gp91(phox) deficiency or by administration of dominant-negative Rac1. Finally, diabetes reduced the ability of adherent bone marrow-derived mononuclear cells (BM-MNCs) to differentiate into endothelial progenitor cells. Treatment with NAC (3 mmol/L), apocynin (200 micromol/L), or the p38MAPK inhibitor LY333351 (10 micromol/L) up-regulated the number of endothelial progenitor cell colonies derived from diabetic BM-MNCs by 1.5-, 1.6-, and 1.5-fold, respectively (P < 0.05). In the ischemic hindlimb model, injection of diabetic BM-MNCs isolated from NAC-treated or gp91(phox)-deficient diabetic mice increased neovascularization by approximately 1.5-fold greater than untreated diabetic BM-MNCs (P < 0.05). Thus, inhibition of NADPH oxidase-derived ROS overproduction improves the angiogenic and vasculogenic processes and restores postischemic neovascularization in type 1 diabetic mice.

  14. TNF-{alpha} upregulates the A{sub 2B} adenosine receptor gene: The role of NAD(P)H oxidase 4

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

    St Hilaire, Cynthia; Koupenova, Milka; Carroll, Shannon H.

    2008-10-24

    Proliferation of vascular smooth muscle cells (VSMC), oxidative stress, and elevated inflammatory cytokines are some of the components that contribute to plaque formation in the vasculature. The cytokine tumor necrosis factor-alpha (TNF-{alpha}) is released during vascular injury, and contributes to lesion formation also by affecting VSMC proliferation. Recently, an A{sub 2B} adenosine receptor (A{sub 2B}AR) knockout mouse illustrated that this receptor is a tissue protector, in that it inhibits VSMC proliferation and attenuates the inflammatory response following injury, including the release of TNF-{alpha}. Here, we show a regulatory loop by which TNF-{alpha} upregulates the A{sub 2B}AR in VSMC in vitromore » and in vivo. The effect of this cytokine is mimicked by its known downstream target, NAD(P)H oxidase 4 (Nox4). Nox4 upregulates the A{sub 2B}AR, and Nox inhibitors dampen the effect of TNF-{alpha}. Hence, our study is the first to show that signaling associated with Nox4 is also able to upregulate the tissue protecting A{sub 2B}AR.« less

  15. Substance P Exacerbates Dopaminergic Neurodegeneration through Neurokinin-1 Receptor-Independent Activation of Microglial NADPH Oxidase

    PubMed Central

    Chu, Chun-Hsien; Qian, Li; Chen, Shih-Heng; Wilson, Belinda; Oyarzabal, Esteban; Jiang, Lulu; Ali, Syed; Robinson, Bonnie; Kim, Hyoung-Chun

    2014-01-01

    Although dysregulated substance P (SP) has been implicated in the pathophysiology of Parkinson's disease (PD), how SP affects the survival of dopaminergic neurons remains unclear. Here, we found that mice lacking endogenous SP (TAC1−/−), but not those deficient in the SP receptor (neurokinin-1 receptor, NK1R), were more resistant to lipopolysaccharide (LPS)- and 1-methyl-4-phenyl-1,2,3,6-tetrahydropyridine (MPTP)-induced nigral dopaminergic neurodegeneration than wild-type controls, suggesting a NK1R-independent toxic action of SP. In vitro dose–response studies revealed that exogenous SP enhanced LPS- and 1-methyl-4-phenylpyridinium (MPP+)-induced dopaminergic neurodegeneration in a bimodal manner, peaking at submicromolar and subpicomolar concentrations, but was substantially less effective at intermediate concentrations. Mechanistically, the actions of submicromolar levels of SP were NK1R-dependent, whereas subpicomolar SP-elicited actions required microglial NADPH oxidase (NOX2), the key superoxide-producing enzyme, but not NK1R. Subpicomolar concentrations of SP activated NOX2 by binding to the catalytic subunit gp91phox and inducing membrane translocation of the cytosolic subunits p47phox and p67phox. The importance of NOX2 was further corroborated by showing that inhibition or disruption of NOX2 blocked subpicomolar SP-exacerbated neurotoxicity. Together, our findings revealed a critical role of microglial NOX2 in mediating the neuroinflammatory and dopaminergic neurodegenerative effects of SP, which may provide new insights into the pathogenesis of PD. PMID:25209287

  16. Activation of PAR-1/NADPH oxidase/ROS signaling pathways is crucial for the thrombin-induced sFlt-1 production in extravillous trophoblasts: possible involvement in the pathogenesis of preeclampsia.

    PubMed

    Huang, Qi-Tao; Chen, Jian-Hong; Hang, Li-Lin; Liu, Shi-San; Zhong, Mei

    2015-01-01

    Preeclampsia was characterized by excessive thrombin generation in placentas and previous researches showed that thrombin could enhance soluble Fms-like tyrosine kinase 1 (sFlt-1) expression in first trimester trophoblasts. However, the detailed mechanism for the sFlt-1 over-production induced by thrombin was largely unknown. The purpose of this study was to explore the possible signaling pathway of thrombin-induced sFlt-1 production in extravillous trophoblasts (EVT). An EVT cell line (HRT-8/SVneo) was treated with various concentrations of thrombin. The mRNA expression and protein secretion of sFlt-1 in EVT were detected with real-time polymerase chain reaction and ELISA, respectively. The levels of intracellular reactive oxygen species (ROS) production were determined by DCFH-DA. Exposure of EVT to thrombin induced increased intracellular ROS generation and overexpression of sFlt-1 at both mRNA and protein levels in a dose dependent manner. Short interfering RNA (siRNA) directed against PAR-1 or apocynin (an inhibitor of NADPH oxidase) could decrease the intracellular ROS generation and subsequently suppressed the production of sFlt-1 at mRNA and protein levels. Our results suggested that thrombin increased sFlt-1 production in EVT via the PAR-1 /NADPH oxidase /ROS signaling pathway. This also highlights the PAR-1 / NADPH oxidase / ROS pathway might be a potential therapeutic target for the prevention of preeclampsia in the future. © 2015 S. Karger AG, Basel.

  17. p47phox Molecular Activation for Assembly of the Neutrophil NADPH Oxidase Complex*

    PubMed Central

    Marcoux, Julien; Man, Petr; Petit-Haertlein, Isabelle; Vivès, Corinne; Forest, Eric; Fieschi, Franck

    2010-01-01

    The p47phox cytosolic factor from neutrophilic NADPH oxidase has always been resistant to crystallogenesis trials due to its modular organization leading to relative flexibility. Hydrogen/deuterium exchange coupled to mass spectrometry was used to obtain structural information on the conformational mechanism that underlies p47phox activation. We confirmed a relative opening of the protein with exposure of the SH3 Src loops that are known to bind p22phox upon activation. A new surface was shown to be unmasked after activation, representing a potential autoinhibitory surface that may block the interaction of the PX domain with the membrane in the resting state. Within this surface, we identified 2 residues involved in the interaction with the PX domain. The double mutant R162A/D166A showed a higher affinity for specific phospholipids but none for the C-terminal part of p22phox, reflecting an intermediate conformation between the autoinhibited and activated forms. PMID:20592030

  18. Macrophage NADPH oxidase flavocytochrome B localizes to the plasma membrane and Rab11-positive recycling endosomes.

    PubMed

    Casbon, Amy-Jo; Allen, Lee-Ann H; Dunn, Kenneth W; Dinauer, Mary C

    2009-02-15

    Flavocytochrome b(558), the catalytic core of the phagocytic NADPH oxidase, mediates the transfer of electrons from NADPH to molecular oxygen to generate superoxide for host defense. Flavocytochrome b is a membrane heterodimer consisting of a large subunit gp91(phox) (NOX2) and a smaller subunit, p22(phox). Although in neutrophils flavocytochrome b has been shown to localize to the plasma membrane and specific granules, little is known about its distribution in macrophages. Using immunofluorescent staining and live cell imaging of fluorescently tagged gp91(phox) and p22(phox), we demonstrate in a Chinese hamster ovary cell model system and in RAW 264.7 and primary murine bone marrow-derived macrophages that flavocytochrome b is found in the Rab11-positive recycling endocytic compartment, as well as in Rab5-positive early endosomes and plasma membrane. Additionally, we show that unassembled p22(phox) and gp91(phox) subunits localize to the endoplasmic reticulum, which redistribute to the cell surface and endosomal compartments following heterodimer formation. These studies show for the first time that flavocytochrome b localizes to intracellular compartments in macrophages that recycle to the plasma membrane, which may act as a reservoir to deliver flavocytochrome b to the cell surface and phagosome membranes.

  19. Aiding and abetting roles of NOX oxidases in cellular transformation

    PubMed Central

    Block, Karen; Gorin, Yves

    2013-01-01

    NADPH oxidases of the NADPH oxidase (NOX) family are dedicated reactive oxygen species-generating enzymes that broadly and specifically regulate redox-sensitive signalling pathways that are involved in cancer development and progression. They act at specific cellular membranes and microdomains through the activation of oncogenes and the inactivation of tumour suppressor proteins. In this Review, we discuss primary targets and redox-linked signalling systems that are influenced by NOX-derived ROS, and the biological role of NOX oxidases in the aetiology of cancer. PMID:22918415

  20. Leptin Induces Oxidative Stress Through Activation of NADPH Oxidase in Renal Tubular Cells: Antioxidant Effect of L-Carnitine.

    PubMed

    Blanca, Antonio J; Ruiz-Armenta, María V; Zambrano, Sonia; Salsoso, Rocío; Miguel-Carrasco, José L; Fortuño, Ana; Revilla, Elisa; Mate, Alfonso; Vázquez, Carmen M

    2016-10-01

    Leptin is a protein involved in the regulation of food intake and in the immune and inflammatory responses, among other functions. Evidences demonstrate that obesity is directly associated with high levels of leptin, suggesting that leptin may directly link obesity with the elevated cardiovascular and renal risk associated with increased body weight. Adverse effects of leptin include oxidative stress mediated by activation of NADPH oxidase. The aim of this study was to evaluate the effect of L-carnitine (LC) in rat renal epithelial cells (NRK-52E) exposed to leptin in order to generate a state of oxidative stress characteristic of obesity. Leptin increased superoxide anion (O2 (•) -) generation from NADPH oxidase (via PI3 K/Akt pathway), NOX2 expression and nitrotyrosine levels. On the other hand, NOX4 expression and hydrogen peroxide (H2 O2 ) levels diminished after leptin treatment. Furthermore, the expression of antioxidant enzymes, catalase, and superoxide dismutase, was altered by leptin, and an increase in the mRNA expression of pro-inflammatory factors was also found in leptin-treated cells. LC restored all changes induced by leptin to those levels found in untreated cells. In conclusion, stimulation of NRK-52E cells with leptin induced a state of oxidative stress and inflammation that could be reversed by preincubation with LC. Interestingly, LC induced an upregulation of NOX4 and restored the release of its product, hydrogen peroxide, which suggests a protective role of NOX4 against leptin-induced renal damage. J. Cell. Biochem. 117: 2281-2288, 2016. © 2016 Wiley Periodicals, Inc. © 2016 Wiley Periodicals, Inc.

  1. Zinc Oxide Nanoparticle Induces Microglial Death by NADPH-Oxidase-Independent Reactive Oxygen Species as well as Energy Depletion.

    PubMed

    Sharma, Anuj Kumar; Singh, Vikas; Gera, Ruchi; Purohit, Mahaveer Prasad; Ghosh, Debabrata

    2017-10-01

    Zinc oxide nanoparticle (ZnO-NP) is one of the most widely used engineered nanoparticles. Upon exposure, nanoparticle can eventually reach the brain through various routes, interact with different brain cells, and alter their activity. Microglia is the fastest glial cell to respond to any toxic insult. Nanoparticle exposure can activate microglia and induce neuroinflammation. Simultaneous to activation, microglial death can exacerbate the scenario. Therefore, we focused on studying the effect of ZnO-NP on microglia and finding out the pathway involved in the microglial death. The present study showed that the 24 h inhibitory concentration 50 (IC 50 ) of ZnO-NP for microglia is 6.6 μg/ml. Early events following ZnO-NP exposure involved increase in intracellular calcium level as well as reactive oxygen species (ROS). Neither of NADPH oxidase inhibitors, apocynin, (APO) and diphenyleneiodonium chloride (DPIC) were able to reduce the ROS level and rescue microglia from ZnO-NP toxicity. In contrary, N-acetyl cysteine (NAC) showed opposite effect. Exogenous supplementation of superoxide dismutase (SOD) reduced ROS significantly even beyond control level but partially rescued microglial viability. Interestingly, pyruvate supplementation rescued microglia near to control level. Following 10 h of ZnO-NP exposure, intracellular ATP level was measured to be almost 50 % to the control. ZnO-NP-induced ROS as well as ATP depletion both disturbed mitochondrial membrane potential and subsequently triggered the apoptotic pathway. The level of apoptosis-inducing proteins was measured by western blot analysis and found to be upregulated. Taken together, we have deciphered that ZnO-NP induced microglial apoptosis by NADPH oxidase-independent ROS as well as ATP depletion.

  2. Substance P exacerbates dopaminergic neurodegeneration through neurokinin-1 receptor-independent activation of microglial NADPH oxidase.

    PubMed

    Wang, Qingshan; Chu, Chun-Hsien; Qian, Li; Chen, Shih-Heng; Wilson, Belinda; Oyarzabal, Esteban; Jiang, Lulu; Ali, Syed; Robinson, Bonnie; Kim, Hyoung-Chun; Hong, Jau-Shyong

    2014-09-10

    Although dysregulated substance P (SP) has been implicated in the pathophysiology of Parkinson's disease (PD), how SP affects the survival of dopaminergic neurons remains unclear. Here, we found that mice lacking endogenous SP (TAC1(-/-)), but not those deficient in the SP receptor (neurokinin-1 receptor, NK1R), were more resistant to lipopolysaccharide (LPS)- and 1-methyl-4-phenyl-1,2,3,6-tetrahydropyridine (MPTP)-induced nigral dopaminergic neurodegeneration than wild-type controls, suggesting a NK1R-independent toxic action of SP. In vitro dose-response studies revealed that exogenous SP enhanced LPS- and 1-methyl-4-phenylpyridinium (MPP(+))-induced dopaminergic neurodegeneration in a bimodal manner, peaking at submicromolar and subpicomolar concentrations, but was substantially less effective at intermediate concentrations. Mechanistically, the actions of submicromolar levels of SP were NK1R-dependent, whereas subpicomolar SP-elicited actions required microglial NADPH oxidase (NOX2), the key superoxide-producing enzyme, but not NK1R. Subpicomolar concentrations of SP activated NOX2 by binding to the catalytic subunit gp91(phox) and inducing membrane translocation of the cytosolic subunits p47(phox) and p67(phox). The importance of NOX2 was further corroborated by showing that inhibition or disruption of NOX2 blocked subpicomolar SP-exacerbated neurotoxicity. Together, our findings revealed a critical role of microglial NOX2 in mediating the neuroinflammatory and dopaminergic neurodegenerative effects of SP, which may provide new insights into the pathogenesis of PD. Copyright © 2014 the authors 0270-6474/14/3412490-14$15.00/0.

  3. Glitazones inhibit human monoamine oxidase but their anti-inflammatory actions are not mediated by VAP-1/semicarbazide-sensitive amine oxidase inhibition.

    PubMed

    Carpéné, Christian; Bizou, Mathilde; Tréguer, Karine; Hasnaoui, Mounia; Grès, Sandra

    2015-09-01

    Glitazones are peroxisome proliferator-activated receptor gamma (PPARγ) agonists widely used as antidiabetic drugs also known as thiazolidinediones. Most of them exert other effects such as anti-inflammatory actions via mechanisms supposed to be independent from PPARγ activation (e.g., decreased plasma monocyte chemoattractant protein-1 (MCP-1) levels). Recently, pioglitazone has been shown to inhibit the B form of monoamine oxidase (MAO) in mouse, while rosiglitazone and troglitazone were described as non-covalent inhibitors of both human MAO A and MAO B. Since molecules interacting with MAO might also inhibit semicarbazide-sensitive amine oxidase (SSAO), known as vascular adhesion protein-1 (VAP-1), and since VAP-1/SSAO inhibitors exhibit anti-inflammatory activity, our aim was to elucidate whether VAP-1/SSAO inhibition could be a mechanism involved in the anti-inflammatory behaviour of glitazones. To this aim, MAO and SSAO activities were measured in human subcutaneous adipose tissue biopsies obtained from overweight women undergoing plastic surgery. The production of hydrogen peroxide, an end-product of amine oxidase activity, was determined in tissue homogenates using a fluorometric method. The oxidation of 1 mM tyramine was inhibited by pargyline and almost resistant to semicarbazide, therefore predominantly MAO-dependent. Rosiglitazone was more potent than pioglitazone in inhibiting tyramine oxidation. By contrast, benzylamine oxidation was only abolished by semicarbazide: hence SSAO-mediated. Pioglitazone hampered SSAO activity only when tested at 1 mM while rosiglitazone was inefficient. However, rosiglitazone exhibited anti-inflammatory activity in human adipocytes by limiting MCP-1 expression. Our observations rule out any involvement of VAP-1/SSAO inhibition and subsequent limitation of leukocyte extravasation in the anti-inflammatory action of glitazones.

  4. NADPH oxidase 2-derived reactive oxygen species in spinal cord microglia contribute to peripheral nerve injury-induced neuropathic pain

    PubMed Central

    Kim, Donghoon; You, Byunghyun; Jo, Eun-Kyeong; Han, Sang-Kyou; Simon, Melvin I.; Lee, Sung Joong

    2010-01-01

    Increasing evidence supports the notion that spinal cord microglia activation plays a causal role in the development of neuropathic pain after peripheral nerve injury; yet the mechanisms for microglia activation remain elusive. Here, we provide evidence that NADPH oxidase 2 (Nox2)-derived ROS production plays a critical role in nerve injury-induced spinal cord microglia activation and subsequent pain hypersensitivity. Nox2 expression was induced in dorsal horn microglia immediately after L5 spinal nerve transection (SNT). Studies using Nox2-deficient mice show that Nox2 is required for SNT-induced ROS generation, microglia activation, and proinflammatory cytokine expression in the spinal cord. SNT-induced mechanical allodynia and thermal hyperalgesia were similarly attenuated in Nox2-deficient mice. In addition, reducing microglial ROS level via intrathecal sulforaphane administration attenuated mechanical allodynia and thermal hyperalgesia in SNT-injured mice. Sulforaphane also inhibited SNT-induced proinflammatory gene expression in microglia, and studies using primary microglia indicate that ROS generation is required for proinflammatory gene expression in microglia. These studies delineate a pathway involving nerve damage leading to microglial Nox2-generated ROS, resulting in the expression of proinflammatory cytokines that are involved in the initiation of neuropathic pain. PMID:20679217

  5. Effects of NADPH oxidase inhibitor on diabetic nephropathy in OLETF rats: the role of reducing oxidative stress in its protective property.

    PubMed

    Nam, Soo Min; Lee, Mi Young; Koh, Jang Hyun; Park, Jun Ho; Shin, Jang Yel; Shin, Young Goo; Koh, Sang Baek; Lee, Eun Young; Chung, Choon Hee

    2009-02-01

    Diabetic nephropathy is the most serious complication in diabetes mellitus. Oxidative stress via nicotinamide adenine dinucleotide phosphate (NADPH) oxidase and vascular endothelial growth factor (VEGF) pathway play critical roles in the development of diabetic nephropathy. We evaluated the effects of apocynin, NADPH oxidase inhibitor on diabetic nephropathy in a type 2 diabetic rat model. Sixteen Otsuka Long Evans Tokushima Fatty (OLETF) rats and 9 Long Evans Tokushima Otsuka (LETO) were divided into the following three groups: LETO rats (n=9), control OLETF rats (n=7) and apocynin-treated OLETF rats (n=9). We examined body weights, plasma glucose levels, urinary albumin-creatinine ratio (ACR) and protein-creatinine ratio (PCR). At 50 weeks, experimental rats were sacrificed and their kidneys were extracted for hematoxylin eosin stain, immunohistochemical VEGF stain and VEGF mRNA real-time RT-PCR. To examine oxidative stress, we checked 24h urinary 8-OHdG (8-hydroxy-2'-deoxyguanosine) and MDA (malondialdehyde). Urinary protein and albumin excretions were reduced after apocynin treatment, though apocynin could not significantly decrease serum glucose levels. There were improvements of glomerular and mesangial expansion in the apocynin-treated OLETF rats. Apocynin significantly decreased optical density of glomerular VEGF expression in immunohistochemical stain and reduced the concentration of 24h urinary 8-OHdG and MDA. From these results, it was suggested that apocynin may have the potential to protect against diabetic nephropathy via amelioration of oxidative stress.

  6. An NADPH Oxidase RBOH Functions in Rice Roots during Lysigenous Aerenchyma Formation under Oxygen-Deficient Conditions

    PubMed Central

    Yoshioka, Miki; Fukazawa, Aya; Nishizawa, Naoko K.

    2017-01-01

    Reactive oxygen species (ROS) produced by the NADPH oxidase, respiratory burst oxidase homolog (RBOH), trigger signal transduction in diverse biological processes in plants. However, the functions of RBOH homologs in rice (Oryza sativa) and other gramineous plants are poorly understood. Ethylene induces the formation of lysigenous aerenchyma, which consists of internal gas spaces created by programmed cell death of cortical cells, in roots of gramineous plants under oxygen-deficient conditions. Here, we report that, in rice, one RBOH isoform (RBOHH) has a role in ethylene-induced aerenchyma formation in roots. Induction of RBOHH expression under oxygen-deficient conditions was greater in cortical cells than in cells of other root tissues. In addition, genes encoding group I calcium-dependent protein kinases (CDPK5 and CDPK13) were strongly expressed in root cortical cells. Coexpression of RBOHH with CDPK5 or CDPK13 induced ROS production in Nicotiana benthamiana leaves. Inhibitors of RBOH activity or cytosolic calcium influx suppressed ethylene-induced aerenchyma formation. Moreover, knockout of RBOHH by CRISPR/Cas9 reduced ROS accumulation and inducible aerenchyma formation in rice roots. These results suggest that RBOHH-mediated ROS production, which is stimulated by CDPK5 and/or CDPK13, is essential for ethylene-induced aerenchyma formation in rice roots under oxygen-deficient conditions. PMID:28351990

  7. Molecular evolution of Phox-related regulatory subunits for NADPH oxidase enzymes

    PubMed Central

    Kawahara, Tsukasa; Lambeth, J David

    2007-01-01

    Background The reactive oxygen-generating NADPH oxidases (Noxes) function in a variety of biological roles, and can be broadly classified into those that are regulated by subunit interactions and those that are regulated by calcium. The prototypical subunit-regulated Nox, Nox2, is the membrane-associated catalytic subunit of the phagocyte NADPH-oxidase. Nox2 forms a heterodimer with the integral membrane protein, p22phox, and this heterodimer binds to the regulatory subunits p47phox, p67phox, p40phox and the small GTPase Rac, triggering superoxide generation. Nox-organizer protein 1 (NOXO1) and Nox-activator 1 (NOXA1), respective homologs of p47phox and p67phox, together with p22phox and Rac, activate Nox1, a non-phagocytic homolog of Nox2. NOXO1 and p22phox also regulate Nox3, whereas Nox4 requires only p22phox. In this study, we have assembled and analyzed amino acid sequences of Nox regulatory subunit orthologs from vertebrates, a urochordate, an echinoderm, a mollusc, a cnidarian, a choanoflagellate, fungi and a slime mold amoeba to investigate the evolutionary history of these subunits. Results Ancestral p47phox, p67phox, and p22phox genes are broadly seen in the metazoa, except for the ecdysozoans. The choanoflagellate Monosiga brevicollis, the unicellular organism that is the closest relatives of multicellular animals, encodes early prototypes of p22phox, p47phox as well as the earliest known Nox2-like ancestor of the Nox1-3 subfamily. p67phox- and p47phox-like genes are seen in the sea urchin Strongylocentrotus purpuratus and the limpet Lottia gigantea that also possess Nox2-like co-orthologs of vertebrate Nox1-3. Duplication of primordial p47phox and p67phox genes occurred in vertebrates, with the duplicated branches evolving into NOXO1 and NOXA1. Analysis of characteristic domains of regulatory subunits suggests a novel view of the evolution of Nox: in fish, p40phox participated in regulating both Nox1 and Nox2, but after the appearance of mammals, Nox1

  8. Defective monocyte oxidative burst predicts infection in alcoholic hepatitis and is associated with reduced expression of NADPH oxidase.

    PubMed

    Vergis, Nikhil; Khamri, Wafa; Beale, Kylie; Sadiq, Fouzia; Aletrari, Mina O; Moore, Celia; Atkinson, Stephen R; Bernsmeier, Christine; Possamai, Lucia A; Petts, Gemma; Ryan, Jennifer M; Abeles, Robin D; James, Sarah; Foxton, Matthew; Hogan, Brian; Foster, Graham R; O'Brien, Alastair J; Ma, Yun; Shawcross, Debbie L; Wendon, Julia A; Antoniades, Charalambos G; Thursz, Mark R

    2017-03-01

    In order to explain the increased susceptibility to serious infection in alcoholic hepatitis, we evaluated monocyte phagocytosis, aberrations of associated signalling pathways and their reversibility, and whether phagocytic defects could predict subsequent infection. Monocytes were identified from blood samples of 42 patients with severe alcoholic hepatitis using monoclonal antibody to CD14. Phagocytosis and monocyte oxidative burst (MOB) were measured ex vivo using flow cytometry, luminometry and bacterial killing assays. Defects were related to the subsequent development of infection. Intracellular signalling pathways were investigated using western blotting and PCR. Interferon-γ (IFN-γ) was evaluated for its therapeutic potential in reversing phagocytic defects. Paired longitudinal samples were used to evaluate the effect of in vivo prednisolone therapy. MOB, production of superoxide and bacterial killing in response to Escherichia coli were markedly impaired in patients with alcoholic hepatitis. Pretreatment MOB predicted development of infection within two weeks with sensitivity and specificity that were superior to available clinical markers. Accordingly, defective MOB was associated with death at 28 and 90 days. Expression of the gp91 phox subunit of nicotinamide adenine dinucleotide phosphate (NADPH) oxidase was reduced in patients with alcoholic hepatitis demonstrating defective MOB. Monocytes were refractory to IFN-γ stimulation and showed high levels of a negative regulator of cytokine signalling, suppressor of cytokine signalling-1. MOB was unaffected by 7 days in vivo prednisolone therapy. Monocyte oxidative burst and bacterial killing is impaired in alcoholic hepatitis while bacterial uptake by phagocytosis is preserved. Defective MOB is associated with reduced expression of NADPH oxidase in these patients and predicts the development of infection and death. Published by the BMJ Publishing Group Limited. For permission to use (where not already

  9. TMEM16A Contributes to Endothelial Dysfunction by Facilitating Nox2 NADPH Oxidase-Derived Reactive Oxygen Species Generation in Hypertension.

    PubMed

    Ma, Ming-Ming; Gao, Min; Guo, Kai-Min; Wang, Mi; Li, Xiang-Yu; Zeng, Xue-Lin; Sun, Lu; Lv, Xiao-Fei; Du, Yan-Hua; Wang, Guan-Lei; Zhou, Jia-Guo; Guan, Yong-Yuan

    2017-05-01

    Ca 2+ -activated Cl - channels play a crucial role in various physiological processes. However, the role of TMEM16A in vascular endothelial dysfunction during hypertension is unclear. In this study, we investigated the specific involvement of TMEM16A in regulating endothelial function and blood pressure and the underlying mechanism. Reverse transcription-polymerase chain reaction, Western blotting, coimmunoprecipitation, confocal imaging, patch-clamp recordings, and TMEM16A endothelial-specific transgenic and knockout mice were used. We found that TMEM16A was expressed abundantly and functioned as a Ca 2+ -activated Cl - channel in endothelial cells. Angiotensin II induced endothelial dysfunction with an increase in TMEM16A expression. The knockout of endothelial-specific TMEM16A significantly lowered the blood pressure and ameliorated endothelial dysfunction in angiotensin II-induced hypertension, whereas the overexpression of endothelial-specific TMEM16A resulted in the opposite effects. These results were related to the increased reactive oxygen species production, Nox2-containing NADPH oxidase activation, and Nox2 and p22phox protein expression that were facilitated by TMEM16A on angiotensin II-induced hypertensive challenge. Moreover, TMEM16A directly bound with Nox2 and reduced the degradation of Nox2 through the proteasome-dependent degradation pathway. Therefore, TMEM16A is a positive regulator of endothelial reactive oxygen species generation via Nox2-containing NADPH oxidase, which induces endothelial dysfunction and hypertension. Modification of TMEM16A may be a novel therapeutic strategy for endothelial dysfunction-associated diseases. © 2017 American Heart Association, Inc.

  10. Release of cystic fibrosis airway inflammatory markers from Pseudomonas aeruginosa-stimulated human neutrophils involves NADPH oxidase-dependent extracellular DNA trap formation.

    PubMed

    Yoo, Dae-goon; Winn, Matthew; Pang, Lan; Moskowitz, Samuel M; Malech, Harry L; Leto, Thomas L; Rada, Balázs

    2014-05-15

    Cystic fibrosis (CF) airways are characterized by bacterial infections, excess mucus production, and robust neutrophil recruitment. The main CF airway pathogen is Pseudomonas aeruginosa. Neutrophils are not capable of clearing the infection. Neutrophil primary granule components, myeloperoxidase (MPO) and human neutrophil elastase (HNE), are inflammatory markers in CF airways, and their increased levels are associated with poor lung function. Identifying the mechanism of MPO and HNE release from neutrophils is of high clinical relevance for CF. In this article, we show that human neutrophils release large amounts of neutrophil extracellular traps (NETs) in the presence of P. aeruginosa. Bacteria are entangled in NETs and colocalize with extracellular DNA. MPO, HNE, and citrullinated histone H4 are all associated with DNA in Pseudomonas-triggered NETs. Both laboratory standard strains and CF isolates of P. aeruginosa induce DNA, MPO, and HNE release from human neutrophils. The increase in peroxidase activity of neutrophil supernatants after Pseudomonas exposure indicates that enzymatically active MPO is released. P. aeruginosa induces a robust respiratory burst in neutrophils that is required for extracellular DNA release. Inhibition of the cytoskeleton prevents Pseudomonas-initiated superoxide production and DNA release. NADPH oxidase inhibition suppresses Pseudomonas-induced release of active MPO and HNE. Blocking MEK/ERK signaling results in only minimal inhibition of DNA release induced by Pseudomonas. Our data describe in vitro details of DNA, MPO, and HNE release from neutrophils activated by P. aeruginosa. We propose that Pseudomonas-induced NET formation is an important mechanism contributing to inflammatory conditions characteristic of CF airways.

  11. Convergent evolution of morphogenetic processes in fungi: Role of tetraspanins and NADPH oxidases 2 in plant pathogens and saprobes.

    PubMed

    Malagnac, Fabienne; Bidard, Frédérique; Lalucque, Hervé; Brun, Sylvain; Lambou, Karine; Lebrun, Marc-Henri; Silar, Philippe

    2008-01-01

    Convergent evolution of trophic life style and morphological characters are very common in the fungal kingdom. Recently, we have shown that the same molecular machinery containing a tetraspanin and a NADPH oxidase has been recruited in two different fungal species for the same purpose (exiting from a melanized re-enforced cell at a focal weakened point), but at different stages of their development (ascospore germination and appressorium mediated penetration). Although this molecular machinery is required at these key developmental steps, it is also likely involved in specialized cellular functions at other stages of fungal development, as shown here for nutrient acquisition by Podospora anserina.

  12. Reactive Oxygen Species Generated by NADPH Oxidases Promote Radicle Protrusion and Root Elongation during Rice Seed Germination

    PubMed Central

    Li, Wen-Yan; Chen, Bing-Xian; Chen, Zhong-Jian; Gao, Yin-Tao; Chen, Zhuang; Liu, Jun

    2017-01-01

    Seed germination is a complicated biological process that requires regulation through various enzymatic and non-enzymatic mechanisms. Although it has been recognized that reactive oxygen species (ROS) regulate radicle emergence and root elongation in a non-enzymatic manner during dicot seed germination, the role of ROS in monocot seed germination remains unknown. NADPH oxidases (NOXs) are the major ROS producers in plants; however, whether and how NOXs regulate rice seed germination through ROS generation remains unclear. Here, we report that diphenyleneiodinium (DPI), a specific NOX inhibitor, potently inhibited embryo and seedling growth—especially that of the radicle and of root elongation—in a dose-dependent manner. Notably, the DPI-mediated inhibition of radicle and root growth could be eliminated by transferring seedlings from DPI to water. Furthermore, ROS production/accumulation during rice seed germination was quantified via histochemistry. Superoxide radicals (O2−), hydrogen peroxide (H2O2) and hydroxyl radicals (•OH) accumulated steadily in the coleorhiza, radicle and seedling root of germinating rice seeds. Expression profiles of the nine typical NOX genes were also investigated. According to quantitative PCR, OsNOX5, 7 and 9 were expressed relatively higher. When seeds were incubated in water, OsNOX5 expression progressively increased in the embryo from 12 to 48 h, whereas OsNOX7 and 9 expressions increased from 12 to 24 h and decreased thereafter. As expected, DPI inhibits the expression at predetermined time points for each of these genes. Taken together, these results suggest that ROS produced by NOXs are involved in radicle and root elongation during rice seed germination, and OsNOX5, 7 and 9 could play crucial roles in rice seed germination. These findings will facilitate further studies of the roles of ROS generated by NOXs during seed germination and seedling establishment and also provide valuable information for the regulation of NOX

  13. Hypouricaemic action of mangiferin results from metabolite norathyriol via inhibiting xanthine oxidase activity.

    PubMed

    Niu, Yanfen; Liu, Jia; Liu, Hai-Yang; Gao, Li-Hui; Feng, Guo-Hua; Liu, Xu; Li, Ling

    2016-09-01

    Context Mangiferin has been reported to possess a potential hypouricaemic effect. However, the pharmacokinetic studies in rats showed that its oral bioavailability was only 1.2%, suggesting that mangiferin metabolites might exert the action. Objective The hypouricaemic effect and the xanthine oxidase inhibition of mangiferin and norathyriol, a mangiferin metabolite, were investigated. Inhibition of norathyriol analogues (compounds 3-9) toward xanthine oxidase was also evaluated. Materials and methods For a dose-dependent study, mangiferin (1.5-6.0 mg/kg) and norathyriol (0.92-3.7 mg/kg) were administered intragastrically to mice twice daily for five times. For a time-course study, mice received mangiferin and norathyriol both at a single dose of 7.1 μmol/kg. In vitro, inhibition of test compounds (2.4-2.4 mM) against xanthine oxidase activity was evaluated by the spectrophotometrical method. The inhibition type was identified from Lineweaver-Burk plots. Results Norathyriol (0.92, 1.85 and 3.7 mg/kg) dose dependently decreased the serum urate levels by 27.0, 33.6 and 37.4%, respectively. The action was more potent than that of mangiferin at the low dose, but was equivalent at the higher doses. Additionally, the hypouricaemic action of them exhibited a time dependence. In vitro, norathyriol markedly inhibited the xanthine oxidase activities, with the IC50 value of 44.6 μM, but mangiferin did not. The kinetic studies showed that norathyriol was an uncompetitive inhibitor by Lineweaver-Burk plots. The structure-activity relationships exhibited that three hydroxyl groups in norathyriol at the C-1, C-3 and C-6 positions were essential for maintaining xanthine oxidase inhibition. Discussion and conclusion Norathyriol was responsible for the hypouricaemic effect of mangiferin via inhibiting xanthine oxidase activity.

  14. Serotonin Signaling Through the 5-HT1B Receptor and NADPH Oxidase 1 in Pulmonary Arterial Hypertension.

    PubMed

    Hood, Katie Y; Mair, Kirsty M; Harvey, Adam P; Montezano, Augusto C; Touyz, Rhian M; MacLean, Margaret R

    2017-07-01

    Serotonin can induce human pulmonary artery smooth muscle cell (hPASMC) proliferation through reactive oxygen species (ROS), influencing the development of pulmonary arterial hypertension (PAH). We hypothesize that in PASMCs, serotonin induces oxidative stress through NADPH-oxidase-derived ROS generation and reduced Nrf-2 (nuclear factor [erythroid-derived 2]-like 2) antioxidant systems, promoting vascular injury. HPASMCs from controls and PAH patients, and PASMCs from Nox1 -/- mice, were stimulated with serotonin in the absence/presence of inhibitors of Src kinase, the 5-HT 1B receptor, and NADPH oxidase 1 (Nox1). Markers of fibrosis were also determined. The pathophysiological significance of our findings was examined in vivo in serotonin transporter overexpressing female mice, a model of pulmonary hypertension. We confirmed thatserotonin increased superoxide and hydrogen peroxide production in these cells. For the first time, we show that serotonin increased oxidized protein tyrosine phosphatases and hyperoxidized peroxiredoxin and decreased Nrf-2 and catalase activity in hPASMCs. ROS generation was exaggerated and dependent on cellular Src-related kinase, 5-HT 1B receptor, and the serotonin transporter in human pulmonary artery smooth muscle cells from PAH subjects. Proliferation and extracellular matrix remodeling were exaggerated in human pulmonary artery smooth muscle cells from PAH subjects and dependent on 5-HT 1B receptor signaling and Nox1, confirmed in PASMCs from Nox1 -/- mice. In serotonin transporter overexpressing mice, SB216641, a 5-HT 1B receptor antagonist, prevented development of pulmonary hypertension in a ROS-dependent manner. Serotonin can induce cellular Src-related kinase-regulated Nox1-induced ROS and Nrf-2 dysregulation, contributing to increased post-translational oxidative modification of proteins and activation of redox-sensitive signaling pathways in hPASMCs, associated with mitogenic responses. 5-HT 1B receptors contribute to

  15. ß-Cyanoalanine Synthase Action in Root Hair Elongation is Exerted at Early Steps of the Root Hair Elongation Pathway and is Independent of Direct Cyanide Inactivation of NADPH Oxidase.

    PubMed

    Arenas-Alfonseca, Lucía; Gotor, Cecilia; Romero, Luis C; García, Irene

    2018-05-01

    In Arabidopsis thaliana, cyanide is produced concomitantly with ethylene biosynthesis and is mainly detoxified by the ß-cyanoalanine synthase CAS-C1. In roots, CAS-C1 activity is essential to maintain a low level of cyanide for proper root hair development. Root hair elongation relies on polarized cell expansion at the growing tip, and we have observed that CAS-C1 locates in mitochondria and accumulates in root hair tips during root hair elongation, as shown by observing the fluorescence in plants transformed with the translational construct ProC1:CASC1-GFP, containing the complete CAS-C1 gene fused to green fluorescent protein (GFP). Mutants in the SUPERCENTIPEDE (SCN1) gene, that regulate the NADPH oxidase gene ROOT HAIR DEFECTIVE 2 (RHD2)/AtrbohC, are affected at the very early steps of the development of root hair that do not elongate and do not show a preferential localization of the GFP accumulation in the tips of the root hair primordia. Root hairs of mutants in CAS-C1 or RHD2/AtrbohC, whose protein product catalyzes the generation of ROS and the Ca2+ gradient, start to grow out correctly, but they do not elongate. Genetic crosses between the cas-c1 mutant and scn1 or rhd2 mutants were performed, and the detailed phenotypic and molecular characterization of the double mutants demonstrates that scn1 mutation is epistatic to cas-c1 and cas-c1 is epistatic to rhd2 mutation, indicating that CAS-C1 acts in early steps of the root hair development process. Moreover, our results show that the role of CAS-C1 in root hair elongation is independent of H2O2 production and of a direct NADPH oxidase inhibition by cyanide.

  16. Carcinogenesis and Reactive Oxygen Species Signaling: Interaction of the NADPH Oxidase NOX1-5 and Superoxide Dismutase 1-3 Signal Transduction Pathways.

    PubMed

    Parascandolo, Alessia; Laukkanen, Mikko O

    2018-04-05

    Reduction/oxidation (redox) balance could be defined as an even distribution of reduction and oxidation complementary processes and their reaction end products. There is a consensus that aberrant levels of reactive oxygen species (ROS), commonly observed in cancer, stimulate primary cell immortalization and progression of carcinogenesis. However, the mechanism how different ROS regulate redox balance is not completely understood. Recent Advances: In the current review, we have summarized the main signaling cascades inducing NADPH oxidase NOX1-5 and superoxide dismutase (SOD) 1-3 expression and their connection to cell proliferation, immortalization, transformation, and CD34 + cell differentiation in thyroid, colon, lung, breast, and hematological cancers. Interestingly, many of the signaling pathways activating redox enzymes or mediating the effect of ROS are common, such as pathways initiated from G protein-coupled receptors and tyrosine kinase receptors involving protein kinase A, phospholipase C, calcium, and small GTPase signaling molecules. The clarification of interaction of signal transduction pathways could explain how cells regulate redox balance and may even provide means to inhibit the accumulation of harmful levels of ROS in human pathologies. Antioxid. Redox Signal. 00, 000-000.

  17. Baccharis trimera inhibits reactive oxygen species production through PKC and down-regulation p47 phox phosphorylation of NADPH oxidase in SK Hep-1 cells.

    PubMed

    de Araújo, Glaucy Rodrigues; Rabelo, Ana Carolina Silveira; Meira, Janaína Serenato; Rossoni-Júnior, Joamyr Victor; Castro-Borges, William de; Guerra-Sá, Renata; Batista, Maurício Azevedo; Silveira-Lemos, Denise da; Souza, Gustavo Henrique Bianco de; Brandão, Geraldo Célio; Chaves, Míriam Martins; Costa, Daniela Caldeira

    2017-02-01

    Baccharis trimera, popularly known as "carqueja", is a native South-American plant possessing a high concentration of polyphenolic compounds and therefore high antioxidant potential. Despite the antioxidant potential described for B. trimera, there are no reports concerning the signaling pathways involved in this process. So, the aim of the present study was to assess the influence of B. trimera on the modulation of PKC signaling pathway and to characterize the effect of the nicotinamide adenine dinucleotide phosphate oxidase enzyme (NOX) on the generation of reactive oxygen species in SK Hep-1 cells. SK-Hep 1 cells were treated with B. trimera, quercetin, or rutin and then stimulated or not with PMA/ionomycin and labeled with carboxy H 2 DCFDA for detection of reactive oxygen species by flow cytometer. The PKC expression by Western blot and enzyme activity was performed to evaluate the influence of B. trimera and quercetin on PKC signaling pathway. p47 phox and p47 phox phosphorylated expression was performed by Western blot to evaluate the influence of B. trimera on p47 phox phosphorylation. The results showed that cells stimulated with PMA/ionomycin (activators of PKC) showed significantly increased reactive oxygen species production, and this production returned to baseline levels after treatment with DPI (NOX inhibitor). Both B. trimera and quercetin modulated reactive oxygen species production through the inhibition of PKC protein expression and enzymatic activity, also with inhibition of p47 phox phosphorylation. Taken together, these results suggest that B. trimera has a potential mechanism for inhibiting reactive oxygen species production through the PKC signaling pathway and inhibition subunit p47 phox phosphorylation of nicotinamide adenine dinucleotide phosphate oxidase.

  18. Inactivation of NADPH oxidases NOX4 and NOX5 protects human primary fibroblasts from ionizing radiation-induced DNA damage.

    PubMed

    Weyemi, Urbain; Redon, Christophe E; Aziz, Towqir; Choudhuri, Rohini; Maeda, Daisuke; Parekh, Palak R; Bonner, Michael Y; Arbiser, Jack L; Bonner, William M

    2015-03-01

    Human exposure to ionizing radiation from medical procedures has increased sharply in the last three decades. Recent epidemiological studies suggest a direct relationship between exposure to ionizing radiation and health problems, including cancer incidence. Therefore, minimizing the impact of radiation exposure in patients has become a priority in the development of future clinical practices. Crucial players in radiation-induced DNA damage include reactive oxygen species (ROS), but the sources of these have remained elusive. To the best of our knowledge, we show here for the first time that two members of the ROS-generating NADPH oxidase family (NOXs), NOX4 and NOX5, are involved in radiation-induced DNA damage. Depleting these two NOXs in human primary fibroblasts resulted in reduced levels of DNA damage as measured by levels of radiation-induced foci, a marker of DNA double-strand breaks (DSBs) and the comet assay coupled with increased cell survival. NOX involvement was substantiated with fulvene-5, a NOXs-specific inhibitor. Moreover, fulvene-5 mitigated radiation-induced DNA damage in human peripheral blood mononuclear cells ex vivo. Our results provide evidence that the inactivation of NOXs protects cells from radiation-induced DNA damage and cell death. These findings suggest that NOXs inhibition may be considered as a future pharmacological target to help minimize the negative effects of radiation exposure for millions of patients each year.

  19. Inactivation of NADPH Oxidases NOX4 and NOX5 Protects Human Primary Fibroblasts from Ionizing Radiation-Induced DNA Damage

    PubMed Central

    Weyemi, Urbain; Redon, Christophe E.; Aziz, Towqir; Choudhuri, Rohini; Maeda, Daisuke; Parekh, Palak R.; Bonner, Michael Y.; Arbiser, Jack L.; Bonner, William M.

    2015-01-01

    Human exposure to ionizing radiation from medical procedures has increased sharply in the last three decades. Recent epidemiological studies suggest a direct relationship between exposure to ionizing radiation and health problems, including cancer incidence. Therefore, minimizing the impact of radiation exposure in patients has become a priority in the development of future clinical practices. Crucial players in radiation-induced DNA damage include reactive oxygen species (ROS), but the sources of these have remained elusive. To the best of our knowledge, we show here for the first time that two members of the ROS-generating NADPH oxidase family (NOXs), NOX4 and NOX5, are involved in radiation-induced DNA damage. Depleting these two NOXs in human primary fibroblasts resulted in reduced levels of DNA damage as measured by levels of radiation-induced foci, a marker of DNA double-strand breaks (DSBs) and the comet assay coupled with increased cell survival. NOX involvement was substantiated with fulvene-5, a NOXs-specific inhibitor. Moreover, fulvene-5 mitigated radiation-induced DNA damage in human peripheral blood mononuclear cells ex vivo. Our results provide evidence that the inactivation of NOXs protects cells from radiation-induced DNA damage and cell death. These findings suggest that NOXs inhibition may be considered as a future pharmacological target to help minimize the negative effects of radiation exposure for millions of patients each year. PMID:25706776

  20. Angiotensin II Inhibits the ROMK-like Small Conductance K Channel in Renal Cortical Collecting Duct during Dietary Potassium Restriction*

    PubMed Central

    Wei, Yuan; Zavilowitz, Beth; Satlin, Lisa M.; Wang, Wen-Hui

    2010-01-01

    Base-line urinary potassium secretion in the distal nephron is mediated by small conductance rat outer medullary K (ROMK)-like channels. We used the patch clamp technique applied to split-open cortical collecting ducts (CCDs) isolated from rats fed a normal potassium (NK) or low potassium (LK) diet to test the hypothesis that AngII directly inhibits ROMK channel activity. We found that AngII inhibited ROMK channel activity in LK but not NK rats in a dose-dependent manner. The AngII-induced reduction in channel activity was mediated by AT1 receptor (AT1R) binding, because pretreatment of CCDs with losartan but not PD123319 AT1 and AT2 receptor antagonists, respectively, blocked the response. Pretreatment of CCDs with U73122 and calphostin C, inhibitors of phospholipase C (PLC) and protein kinase C (PKC), respectively, abolished the AngII-induced decrease in ROMK channel activity, confirming a role of the PLC-PKC pathway in this response. Studies by others suggest that AngII stimulates an Src family protein-tyrosine kinase (PTK) via PKC-NADPH oxidase. PTK has been shown to regulate the ROMK channel. Inhibition of NADPH oxidase with diphenyliodonium abolished the inhibitory effect of AngII or the PKC activator phorbol 12-myristate 13-acetate on ROMK channels. Suppression of PTK by herbimycin A significantly attenuated the inhibitory effect of AngII on ROMK channel activity. We conclude that AngII inhibits ROMK channel activity through PKC-, NADPH oxidase-, and PTK-dependent pathways under conditions of dietary potassium restriction. PMID:17194699

  1. Angiotensin II inhibits the ROMK-like small conductance K channel in renal cortical collecting duct during dietary potassium restriction.

    PubMed

    Wei, Yuan; Zavilowitz, Beth; Satlin, Lisa M; Wang, Wen-Hui

    2007-03-02

    Base-line urinary potassium secretion in the distal nephron is mediated by small conductance rat outer medullary K (ROMK)-like channels. We used the patch clamp technique applied to split-open cortical collecting ducts (CCDs) isolated from rats fed a normal potassium (NK) or low potassium (LK) diet to test the hypothesis that AngII directly inhibits ROMK channel activity. We found that AngII inhibited ROMK channel activity in LK but not NK rats in a dose-dependent manner. The AngII-induced reduction in channel activity was mediated by AT1 receptor (AT1R) binding, because pretreatment of CCDs with losartan but not PD123319 AT1 and AT2 receptor antagonists, respectively, blocked the response. Pretreatment of CCDs with U73122 and calphostin C, inhibitors of phospholipase C (PLC) and protein kinase C (PKC), respectively, abolished the AngII-induced decrease in ROMK channel activity, confirming a role of the PLC-PKC pathway in this response. Studies by others suggest that AngII stimulates an Src family protein-tyrosine kinase (PTK) via PKC-NADPH oxidase. PTK has been shown to regulate the ROMK channel. Inhibition of NADPH oxidase with diphenyliodonium abolished the inhibitory effect of AngII or the PKC activator phorbol 12-myristate 13-acetate on ROMK channels. Suppression of PTK by herbimycin A significantly attenuated the inhibitory effect of AngII on ROMK channel activity. We conclude that AngII inhibits ROMK channel activity through PKC-, NADPH oxidase-, and PTK-dependent pathways under conditions of dietary potassium restriction.

  2. Root growth restraint can be an acclimatory response to low pH and is associated with reduced cell mortality: a possible role of class III peroxidases and NADPH oxidases.

    PubMed

    Graças, J P; Ruiz-Romero, R; Figueiredo, L D; Mattiello, L; Peres, L E P; Vitorello, V A

    2016-07-01

    Low pH (<5.0) can significantly decrease root growth but whether this is a direct effect of H(+) or an active plant response is examined here. Tomato (Solanum lycopersicum cv Micro-Tom) roots were exposed directly or gradually to low pH through step-wise changes in pH over periods ranging from 4 to 24 h. Roots exposed gradually to pH 4.5 grew even less than those exposed directly, indicating a plant-coordinated response. Direct exposure to pH 4.0 suppressed root growth and caused high cell mortality, in contrast to roots exposed gradually, in which growth remained inhibited but cell viability was maintained. Total class III peroxidase activity increased significantly in all low pH treatments, but was not correlated with the observed differential responses. Use of the enzyme inhibitors salicylhydroxamic acid (SHAM) or diphenyleneiodonium chloride (DPI) suggest that peroxidase and, to a lesser extent, NADPH oxidase were required to prevent or reduce injury in all low pH treatments. However, a role for other enzymes, such as the alternative oxidase is also possible. The results with SHAM, but not DPI, were confirmed in tobacco BY-2 cells. Our results indicate that root growth inhibition from low pH can be part of an active plant response, and suggest that peroxidases may have a critical early role in reducing loss of cell viability and in the observed root growth constraint. © 2016 German Botanical Society and The Royal Botanical Society of the Netherlands.

  3. Pathophysiology and Treatments of Oxidative Injury in Ischemic Stroke: Focus on the Phagocytic NADPH Oxidase 2

    PubMed Central

    Carbone, Federico; Teixeira, Priscila Camillo; Braunersreuther, Vincent; Mach, François; Vuilleumier, Nicolas

    2015-01-01

    Abstract Significance: Phagocytes play a key role in promoting the oxidative stress after ischemic stroke occurrence. The phagocytic NADPH oxidase (NOX) 2 is a membrane-bound enzyme complex involved in the antimicrobial respiratory burst and free radical production in these cells. Recent Advances: Different oxidants have been shown to induce opposite effects on neuronal homeostasis after a stroke. However, several experimental models support the detrimental effects of NOX activity (especially the phagocytic isoform) on brain recovery after stroke. Therapeutic strategies selectively targeting the neurotoxic ROS and increasing neuroprotective oxidants have recently produced promising results. Critical Issues: NOX2 might promote carotid plaque rupture and stroke occurrence. In addition, NOX2-derived reactive oxygen species (ROS) released by resident and recruited phagocytes enhance cerebral ischemic injury, activating the inflammatory apoptotic pathways. The aim of this review is to update evidence on phagocyte-related oxidative stress, focusing on the role of NOX2 as a potential therapeutic target to reduce ROS-related cerebral injury after stroke. Future Directions: Radical scavenger compounds (such as Ebselen and Edaravone) are under clinical investigation as a therapeutic approach against stroke. On the other hand, NOX inhibition might represent a promising strategy to prevent the stroke-related injury. Although selective NOX inhibitors are not yet available, nonselective compounds (such as apocynin and fasudil) provided encouraging results in preclinical studies. Whereas additional studies are needed to better evaluate this therapeutic potential in human beings, the development of specific NOX inhibitors (such as monoclonal antibodies, small-molecule inhibitors, or aptamers) might further improve brain recovery after stroke. Antioxid. Redox Signal. 23, 460–489. PMID:24635113

  4. Decursin attenuates hepatic fibrogenesis through interrupting TGF-beta-mediated NAD(P)H oxidase activation and Smad signaling in vivo and in vitro.

    PubMed

    Choi, Young Ji; Kim, Da Hye; Kim, Sang Jun; Kim, Ju; Jeong, Seung-Il; Chung, Chang Ho; Yu, Kang-Yeol; Kim, Seon-Young

    2014-07-17

    We studied that a potent antifibrotic effect of decursin on in vivo liver damage model and the mechanism in inhibiting which transforming growth factor (TGF)-β1-induced human hepatic stellate cells (HSCs) activation. Liver injury was induced in vivo by intraperitoneal injection of carbon tetrachloride (CCl4) with or without decursin for 4weeks in mice. Human hepatic stellate cell line, an immortalized human HSC line, was used in in vitro assay system. The effects of decursin on HSC activation were measured by analyzing the expression of α-smooth muscle actin (α-SMA) and collagen I in liver tissue and human HSCs. Decursin treatment significantly reduced the ratio of liver/body weight, α-SMA activation, and type I collagen overexpression in CCl4 treated mice liver. The elevated serum levels, including ALT, AST, and ALP, were also decreased by decursin treatment. Treatment of decursin markedly proved the generation of reactive oxygen species, NAD(P)H oxidase (NOX) protein (1, 2, and 4) upregulation, NOX activity, and superoxide anion production in HSCs by TGF-β1. It also significantly reduced TGF-β1-induced Smad 2/3 phosphorylation, nuclear translocation of Smad 4, and association of Smad 2/3-Smad 4 complex. Consistent with in vitro results, decursin treatment effectively blocked the levels of NOX protein, and Smad 2/3 phosphorylation in injured mice liver. Decursin blocked CCl4-induced liver fibrosis and inhibited TGF-β1-mediated HSC activation in vitro. These data demonstrated that decursin exhibited hepatoprotective effects on experimental fibrosis, potentially by inhibiting the TGF-β1 induced NOX activation and Smad signaling. Copyright © 2014 Elsevier Inc. All rights reserved.

  5. Delivery of Nox2-NADPH oxidase siRNA with polyketal nanoparticles for improving cardiac function following myocardial infarction.

    PubMed

    Somasuntharam, Inthirai; Boopathy, Archana V; Khan, Raffay S; Martinez, Mario D; Brown, Milton E; Murthy, Niren; Davis, Michael E

    2013-10-01

    Myocardial infarction (MI) is the most common cause of heart failure (HF), the leading cause of death in the developed world. Oxidative stress due to excessive production of reactive oxygen species (ROS) plays a key role in the pathogenesis of cardiac remodeling leading to HF. NADPH oxidase with Nox2 as the catalytic subunit is a major source for cardiac ROS production. Nox2-NADPH expression is significantly increased in the infarcted myocardium, primarily in neutrophils, macrophages and myocytes. Moreover, mice lacking the Nox2 gene are protected from ischemic injury, implicating Nox2 as a potential therapeutic target. RNAi-mediated gene silencing holds great promise as a therapeutic owing to its high specificity and potency. However, in vivo delivery hurdles have limited its effective clinical use. Here, we demonstrate acid-degradable polyketal particles as delivery vehicles for Nox2-siRNA to the post-MI heart. In vitro, Nox2-siRNA particles are effectively taken up by macrophages and significantly knockdown Nox2 expression and activity. Following in vivo intramyocardial injection in experimental mice models of MI, Nox2-siRNA particles prevent upregulation of Nox2 and significantly recovered cardiac function. This study highlights the potential of polyketals as siRNA delivery vehicles to the MI heart and represents a viable therapeutic approach for targeting oxidative stress. Copyright © 2013 Elsevier Ltd. All rights reserved.

  6. Roles of Nicotinamide Adenine Dinucleotide Phosphate (NADPH) Oxidase in Angiogenesis: Isoform-Specific Effects

    PubMed Central

    Wang, Haibo; Hartnett, M. Elizabeth

    2017-01-01

    Angiogenesis is the formation of new blood vessels from preexisting ones and is implicated in physiologic vascular development, pathologic blood vessel growth, and vascular restoration. This is in contrast to vasculogenesis, which is de novo growth of vessels from vascular precursors, or from vascular repair that occurs when circulating endothelial progenitor cells home into an area and develop into blood vessels. The objective of this review is to discuss the isoform-specific role of nicotinamide adenine dinucleotide phosphate (NADPH) oxidase (NOX) in physiologic and pathologic angiogenesis and vascular repair, but will not specifically address vasculogenesis. As the major source of reactive oxygen species (ROS) in vascular endothelial cells (ECs), NOX has gained increasing attention in angiogenesis. Activation of NOX leads to events necessary for physiologic and pathologic angiogenesis, including EC migration, proliferation and tube formation. However, activation of different NOX isoforms has different effects in angiogenesis. Activation of NOX2 promotes pathologic angiogenesis and vascular inflammation, but may be beneficial in revascularization in the hindlimb ischemic model. In contrast, activation of NOX4 appears to promote physiologic angiogenesis mainly by protecting the vasculature during ischemia, hypoxia and inflammation and by restoring vascularization, except in models of oxygen-induced retinopathy and diabetes where NOX4 activation leads to pathologic angiogenesis. PMID:28587189

  7. Differential Expression of NADPH Oxidases Depends on Skeletal Muscle Fiber Type in Rats.

    PubMed

    Loureiro, Adriano César Carneiro; do Rêgo-Monteiro, Igor Coutinho; Louzada, Ruy A; Ortenzi, Victor Hugo; de Aguiar, Angélica Ponte; de Abreu, Ewerton Sousa; Cavalcanti-de-Albuquerque, João Paulo Albuquerque; Hecht, Fabio; de Oliveira, Ariclécio Cunha; Ceccatto, Vânia Marilande; Fortunato, Rodrigo S; Carvalho, Denise P

    2016-01-01

    NADPH oxidases (NOX) are important sources of reactive oxygen species (ROS) in skeletal muscle, being involved in excitation-contraction coupling. Thus, we aimed to investigate if NOX activity and expression in skeletal muscle are fiber type specific and the possible contribution of this difference to cellular oxidative stress. Oxygen consumption rate, NOX activity and mRNA levels, and the activity of catalase (CAT), glutathione peroxidase (GPX), and superoxide dismutase (SOD), as well as the reactive protein thiol levels, were measured in the soleus (SOL), red gastrocnemius (RG), and white gastrocnemius (WG) muscles of rats. RG showed higher oxygen consumption flow than SOL and WG, while SOL had higher oxygen consumption than WG. SOL showed higher NOX activity, as well as NOX2 and NOX4 mRNA levels, antioxidant enzymatic activities, and reactive protein thiol contents when compared to WG and RG. NOX activity and NOX4 mRNA levels as well as antioxidant enzymatic activities were higher in RG than in WG. Physical exercise increased NOX activity in SOL and RG, specifically NOX2 mRNA levels in RG and NOX4 mRNA levels in SOL. In conclusion, we demonstrated that NOX activity and expression differ according to the skeletal muscle fiber type, as well as antioxidant defense.

  8. Quantitative interaction analysis permits molecular insights into functional NOX4 NADPH oxidase heterodimer assembly.

    PubMed

    O'Neill, Sharon; Mathis, Magalie; Kovačič, Lidija; Zhang, Suisheng; Reinhardt, Jürgen; Scholz, Dimitri; Schopfer, Ulrich; Bouhelal, Rochdi; Knaus, Ulla G

    2018-06-08

    Protein-protein interactions critically regulate many biological systems, but quantifying functional assembly of multipass membrane complexes in their native context is still challenging. Here, we combined modeling-assisted protein modification and information from human disease variants with a minimal-size fusion tag, split-luciferase-based approach to probe assembly of the NADPH oxidase 4 (NOX4)-p22 phox enzyme, an integral membrane complex with unresolved structure, which is required for electron transfer and generation of reactive oxygen species (ROS). Integrated analyses of heterodimerization, trafficking, and catalytic activity identified determinants for the NOX4-p22 phox interaction, such as heme incorporation into NOX4 and hot spot residues in transmembrane domains 1 and 4 in p22 phox Moreover, their effect on NOX4 maturation and ROS generation was analyzed. We propose that this reversible and quantitative protein-protein interaction technique with its small split-fragment approach will provide a protein engineering and discovery tool not only for NOX research, but also for other intricate membrane protein complexes, and may thereby facilitate new drug discovery strategies for managing NOX-associated diseases. © 2018 by The American Society for Biochemistry and Molecular Biology, Inc.

  9. Endothelial microparticle formation by angiotensin II is mediated via Ang II receptor type I/NADPH oxidase/ Rho kinase pathways targeted to lipid rafts.

    PubMed

    Burger, Dylan; Montezano, Augusto C; Nishigaki, Nobuhiro; He, Ying; Carter, Anthony; Touyz, Rhian M

    2011-08-01

    Circulating microparticles are increased in cardiovascular disease and may themselves promote oxidative stress and inflammation. Molecular mechanisms underlying their formation and signaling are unclear. We investigated the role of reactive oxygen species (ROS), Rho kinase, and lipid rafts in microparticle formation and examined their functional significance in endothelial cells (ECs). Microparticle formation from angiotensin II (Ang II)-stimulated ECs and apolipoprotein E(-/-) mice was assessed by annexin V or by CD144 staining and electron microscopy. Ang II promoted microparticle formation and increased EC O(2)(-) generation and Rho kinase activity. Ang II-stimulated effects were inhibited by irbesartan (Ang II receptor type I blocker) and fasudil (Rho kinase inhibitor). Methyl-β-cyclodextrin and nystatin, which disrupt lipid rafts/caveolae, blocked microparticle release. Functional responses, assessed in microparticle-stimulated ECs, revealed increased O(2)(-) production, enhanced vascular cell adhesion molecule/platelet-EC adhesion molecule expression, and augmented macrophage adhesion. Inhibition of epidermal growth factor receptor blocked the prooxidative and proinflammatory effects of microparticles. In vitro observations were confirmed in apolipoprotein E(-/-) mice, which displayed vascular inflammation and high levels of circulating endothelial microparticles, effects that were reduced by apocynin. We demonstrated direct actions of Ang II on endothelial microparticle release, mediated through NADPH oxidase, ROS, and Rho kinase targeted to lipid rafts. Microparticles themselves stimulated endothelial ROS formation and inflammatory responses. Our findings suggest a feedforward system whereby Ang II promotes EC injury through its own endothelial-derived microparticles.

  10. Activation of caspase-1 by the NLRP3 inflammasome regulates the NADPH oxidase NOX2 to control phagosome function

    PubMed Central

    Sokolovska, Anna; Becker, Christine E.; Eddie Ip, WK; Rathinam, Vijay A.K.; Brudner, Matthew; Paquette, Nicholas; Tanne, Antoine; Vanaja, Sivapriya K.; Moore, Kathryn J.; Fitzgerald, Katherine A.; Lacy-Hulbert, Adam; Stuart, Lynda M.

    2013-01-01

    Phagocytosis is a fundamental cellular process that is pivotal for immunity as it coordinates microbial killing, innate immune activation and antigen presentation. An essential step in this process is phagosome acidification, which regulates a number of functions of these organelles that allow them to participate in processes essential to both innate and adaptive immunity. Here we report that acidification of phagosomes containing Gram-positive bacteria is regulated by the NLRP3-inflammasome and caspase-1. Active caspase-1 accumulates on phagosomes and acts locally to control the pH by modulating buffering by the NADPH oxidase NOX2. These data provide insight into a mechanism by which innate immune signals can modify cellular defenses and establish a new function for the NLRP3-inflammasome and caspase-1 in host defense. PMID:23644505

  11. Cognitive Function in Prepubertal Children with Obstructive Sleep Apnea: A Modifying Role for NADPH Oxidase p22 Subunit Gene Polymorphisms?

    PubMed Central

    Khalyfa, Abdelnaby; Capdevila, Oscar Sans; Kheirandish-Gozal, Leila; Khalyfa, Ahamed A.; Kim, Jinkwan

    2012-01-01

    Abstract Pediatric obstructive sleep apnea (OSA) may lead to neurocognitive dysfunction, but not in everyone affected. The frequencies of NADPH oxidase (NOX) polymorphisms in the p22phox subunit were similar between children with OSA and controls, except for rs6520785 and rs4673, the latter being significantly more frequent among the OSA children without deficits than with deficits (p<0.02). Similarly, 8-hydroxydeoxyguanine urine levels and NOX activity were lower among children without cognitive deficits and particularly among those with the rs4673 polymorphism. Thus, polymorphisms within the NOX gene or its functional subunits may account for important components of the variance in cognitive function deficits associated with OSA in children. Antioxid. Redox Signal. 16, 171–177. PMID:21902598

  12. Neuronal Nitric Oxide Synthase and NADPH Oxidase Interact to Affect Cognitive, Affective, and Social Behaviors in Mice

    PubMed Central

    Walton, James C.; Selvakumar, Balakrishnan; Weil, Zachary M.; Snyder, Solomon H.; Nelson, Randy J.

    2013-01-01

    Both nitric oxide (NO) and reactive oxygen species (ROS) generated by nNOS and NADPH oxidase (NOX), respectively, in the brain have been implicated in an array of behaviors ranging from learning and memory to social interactions. Although recent work has elucidated how these separate redox pathways regulate neural function and behavior, the interaction of these two pathways in the regulation of neural function and behavior remains unspecified. Toward this end, the p47phox subunit of NOX, and nNOS were deleted to generate double knockout mice that were used to characterize the behavioral outcomes of concurrent impairment of the NO and ROS pathways in the brain. Mice were tested in a battery of behavioral tasks to evaluate learning and memory, as well as social, affective, and cognitive behaviors. p47phox deletion did not affect depressive-like behavior, whereas nNOS deletion abolished it. Both p47phox and nNOS deletion singly reduced anxiety-like behavior, increased general locomotor activity, impaired spatial learning and memory, and impaired preference for social novelty. Deletion of both genes concurrently had synergistic effects to elevate locomotor activity, impair spatial learning and memory, and disrupt prepulse inhibition of acoustic startle. Although preference for social novelty was impaired in single knockouts, double knockout mice displayed elevated levels of preference for social novelty above that of wild type littermates. These data demonstrate that, depending upon modality, deletion of p47phox and nNOS genes have dissimilar, similar, or additive effects. The current findings provide evidence that the NOX and nNOS redox signaling cascades interact in the brain to affect both cognitive function and social behavior. PMID:23948215

  13. A Nonpolar Blueberry Fraction Blunts NADPH Oxidase Activation in Neuronal Cells Exposed to Tumor Necrosis Factor-α

    PubMed Central

    Gustafson, Sally J.; Dunlap, Kriya L.; McGill, Colin M.; Kuhn, Thomas B.

    2012-01-01

    Inflammation and oxidative stress are key to the progressive neuronal degeneration common to chronic pathologies, traumatic injuries, and aging processes in the CNS. The proinflammatory cytokine tumor necrosis factor-alpha (TNF-α) orchestrates cellular stress by stimulating the production and release of neurotoxic mediators including reactive oxygen species (ROS). NADPH oxidases (NOX), ubiquitously expressed in all cells, have recently emerged as pivotal ROS sources in aging and disease. We demonstrated the presence of potent NOX inhibitors in wild Alaska bog blueberries partitioning discretely into a nonpolar fraction with minimal antioxidant capacity and largely devoid of polyphenols. Incubation of SH-SY5Y human neuroblastoma cells with nonpolar blueberry fractions obstructed the coalescing of lipid rafts into large domains disrupting NOX assembly therein and abolishing ROS production characteristic for TNF-α exposure. These findings illuminate nutrition-derived lipid raft modulation as a novel therapeutic approach to blunt inflammatory and oxidative stress in the aging or diseased CNS. PMID:22530077

  14. Association of a variant in the regulatory region of NADPH oxidase 4 gene and metabolic syndrome in patients with chronic hepatitis C.

    PubMed

    Siqueira, Erika Rabelo Forte de; Pereira, Luciano Beltrao; Stefano, Jose Tadeu; Patente, Thiago; Cavaleiro, Ana Mercedes; Silva Vasconcelos, Luydson Richardson; Carmo, Rodrigo Feliciano; Moreira Beltrao Pereira, Leila Maria; Carrilho, Flair Jose; Corrêa-Giannella, Maria Lucia; Oliveira, Claudia P

    2015-03-28

    Given the important contribution of the nicotinamide adenine dinucleotide phosphate (NADPH) oxidase system to the generation of reactive oxygen species induced by hepatitis C virus (HCV), we investigated two single nucleotide polymorphisms (SNPs) in the putative regulatory region of the genes encoding NADPH oxidase 4 catalytic subunit (NOX4) and its regulatory subunit p22phox (CYBA) and their relation with metabolic and histological variables in patients with HCV. One hundred seventy eight naïve HCV patients (49.3% male; 65% HCV genotype 1) with positive HCV RNA were genotyped using specific primers and fluorescent-labeled probes for SNPs rs3017887 in NOX4 and -675 T → A in CYBA. No association was found between the genotype frequencies of NOX4 and CYBA SNPs and inflammation scores or fibrosis stages in the overall population. The presence of the CA + AA genotypes of the NOX4 SNP was nominally associated with a lower alanine aminotransferase (ALT) concentration in the male population (CA + AA = 72.23 ± 6.34 U/L versus CC = 100.22 ± 9.85; mean ± SEM; P = 0.05). The TT genotype of the CYBA SNP was also nominally associated with a lower ALT concentration in the male population (TT = 84.01 ± 6.77 U/L versus TA + AA = 109.67 ± 18.37 U/L; mean ± SEM; P = 0.047). The minor A-allele of the NOX4 SNP was inversely associated with the frequency of metabolic syndrome (MS) in the male population (odds ratio (OR): 0.15; 95% confidence interval (CI): 0.03 to 0.79; P = 0.025). The results suggest that the evaluated NOX4 and CYBA SNPs are not direct genetic determinants of fibrosis in HCV patients, but nevertheless NOX4 rs3017887 SNP could indirectly influence fibrosis susceptibility due to its inverse association with MS in male patients.

  15. Resveratrol improves left ventricular diastolic relaxation in type 2 diabetes by inhibiting oxidative/nitrative stress: in vivo demonstration with magnetic resonance imaging

    PubMed Central

    Zhang, Hanrui; Morgan, Brandon; Potter, Barry J.; Ma, Lixin; Dellsperger, Kevin C.; Ungvari, Zoltan

    2010-01-01

    Resveratrol is a natural phytophenol that exhibits cardioprotective effects. This study was designed to elucidate the mechanisms by which resveratrol protects against diabetes-induced cardiac dysfunction. Normal control (m-Leprdb) mice and type 2 diabetic (Leprdb) mice were treated with resveratrol orally for 4 wk. In vivo MRI showed that resveratrol improved cardiac function by increasing the left ventricular diastolic peak filling rate in Leprdb mice. This protective role is partially explained by resveratrol's effects in improving nitric oxide (NO) production and inhibiting oxidative/nitrative stress in cardiac tissue. Resveratrol increased NO production by enhancing endothelial NO synthase (eNOS) expression and reduced O2·− production by inhibiting NAD(P)H oxidase activity and gp91phox mRNA and protein expression. The increased nitrotyrosine (N-Tyr) protein expression in Leprdb mice was prevented by the inducible NO synthase (iNOS) inhibitor 1400W. Resveratrol reduced both N-Tyr and iNOS expression in Leprdb mice. Furthermore, TNF-α mRNA and protein expression, as well as NF-κB activation, were reduced in resveratrol-treated Leprdb mice. Both Leprdb mice null for TNF-α (dbTNF−/dbTNF− mice) and Leprdb mice treated with the NF-κB inhibitor MG-132 showed decreased NAD(P)H oxidase activity and iNOS expression as well as elevated eNOS expression, whereas m-Leprdb mice treated with TNF-α showed the opposite effects. Thus, resveratrol protects against cardiac dysfunction by inhibiting oxidative/nitrative stress and improving NO availability. This improvement is due to the role of resveratrol in inhibiting TNF-α-induced NF-κB activation, therefore subsequently inhibiting the expression and activation of NAD(P)H oxidase and iNOS as well as increasing eNOS expression in type 2 diabetes. PMID:20675566

  16. Contribution of NADPH Oxidase to Membrane CD38 Internalization and Activation in Coronary Arterial Myocytes

    PubMed Central

    Xu, Ming; Li, Xiao-Xue; Ritter, Joseph K.; Abais, Justine M.; Zhang, Yang; Li, Pin-Lan

    2013-01-01

    The CD38-ADP-ribosylcyclase-mediated Ca2+ signaling pathway importantly contributes to the vasomotor response in different arteries. Although there is evidence indicating that the activation of CD38-ADP-ribosylcyclase is associated with CD38 internalization, the molecular mechanism mediating CD38 internalization and consequent activation in response to a variety of physiological and pathological stimuli remains poorly understood. Recent studies have shown that CD38 may sense redox signals and is thereby activated to produce cellular response and that the NADPH oxidase isoform, NOX1, is a major resource to produce superoxide (O2 ·−) in coronary arterial myocytes (CAMs) in response to muscarinic receptor agonist, which uses CD38-ADP-ribosylcyclase signaling pathway to exert its action in these CAMs. These findings led us hypothesize that NOX1-derived O2 ·− serves in an autocrine fashion to enhance CD38 internalization, leading to redox activation of CD38-ADP-ribosylcyclase activity in mouse CAMs. To test this hypothesis, confocal microscopy, flow cytometry and a membrane protein biotinylation assay were used in the present study. We first demonstrated that CD38 internalization induced by endothelin-1 (ET-1) was inhibited by silencing of NOX1 gene, but not NOX4 gene. Correspondingly, NOX1 gene silencing abolished ET-1-induced O2 ·− production and increased CD38-ADP-ribosylcyclase activity in CAMs, while activation of NOX1 by overexpression of Rac1 or Vav2 or administration of exogenous O2 ·− significantly increased CD38 internalization in CAMs. Lastly, ET-1 was found to markedly increase membrane raft clustering as shown by increased colocalization of cholera toxin-B with CD38 and NOX1. Taken together, these results provide direct evidence that Rac1-NOX1-dependent O2 ·− production mediates CD38 internalization in CAMs, which may represent an important mechanism linking receptor activation with CD38 activity in these cells. PMID:23940720

  17. NADPH oxidase promotes Parkinsonian phenotypes by impairing autophagic flux in an mTORC1-independent fashion in a cellular model of Parkinson’s disease

    PubMed Central

    Pal, Rituraj; Bajaj, Lakshya; Sharma, Jaiprakash; Palmieri, Michela; Di Ronza, Alberto; Lotfi, Parisa; Chaudhury, Arindam; Neilson, Joel; Sardiello, Marco; Rodney, George G.

    2016-01-01

    Oxidative stress and aberrant accumulation of misfolded proteins in the cytosol are key pathological features associated with Parkinson’s disease (PD). NADPH oxidase (Nox2) is upregulated in the pathogenesis of PD; however, the underlying mechanism(s) of Nox2-mediated oxidative stress in PD pathogenesis are still unknown. Using a rotenone-inducible cellular model of PD, we observed that a short exposure to rotenone (0.5 μM) resulted in impaired autophagic flux through activation of a Nox2 dependent Src/PI3K/Akt axis, with a consequent disruption of a Beclin1-VPS34 interaction that was independent of mTORC1 activity. Sustained exposure to rotenone at a higher dose (10 μM) decreased mTORC1 activity; however, autophagic flux was still impaired due to dysregulation of lysosomal activity with subsequent induction of the apoptotic machinery. Cumulatively, our results highlight a complex pathogenic mechanism for PD where short- and long-term oxidative stress alters different signaling pathways, ultimately resulting in anomalous autophagic activity and disease phenotype. Inhibition of Nox2-dependent oxidative stress attenuated the impaired autophagy and cell death, highlighting the importance and therapeutic potential of these pathways for treating patients with PD. PMID:26960433

  18. NADPH oxidase 1 supports proliferation of colon cancer cells by modulating reactive oxygen species-dependent signal transduction

    PubMed Central

    Juhasz, Agnes; Markel, Susan; Gaur, Shikha; Liu, Han; Lu, Jiamo; Jiang, Guojian; Wu, Xiwei; Antony, Smitha; Wu, Yongzhong; Melillo, Giovanni; Meitzler, Jennifer L.; Haines, Diana C.; Butcher, Donna; Roy, Krishnendu; Doroshow, James H.

    2017-01-01

    Reactive oxygen species (ROS) play a critical role in cell signaling and proliferation. NADPH oxidase 1 (NOX1), a membrane-bound flavin dehydrogenase that generates O2˙̄, is highly expressed in colon cancer. To investigate the role that NOX1 plays in colon cancer growth, we used shRNA to decrease NOX1 expression stably in HT-29 human colon cancer cells. The 80–90% decrease in NOX1 expression achieved by RNAi produced a significant decline in ROS production and a G1/S block that translated into a 2–3-fold increase in tumor cell doubling time without increased apoptosis. The block at the G1/S checkpoint was associated with a significant decrease in cyclin D1 expression and profound inhibition of mitogen-activated protein kinase (MAPK) signaling. Decreased steady-state MAPK phosphorylation occurred concomitant with a significant increase in protein phosphatase activity for two colon cancer cell lines in which NOX1 expression was knocked down by RNAi. Diminished NOX1 expression also contributed to decreased growth, blood vessel density, and VEGF and hypoxia-inducible factor 1α (HIF-1α) expression in HT-29 xenografts initiated from NOX1 knockdown cells. Microarray analysis, supplemented by real-time PCR and Western blotting, revealed that the expression of critical regulators of cell proliferation and angiogenesis, including c-MYC, c-MYB, and VEGF, were down-regulated in association with a decline in hypoxic HIF-1α protein expression downstream of silenced NOX1 in both colon cancer cell lines and xenografts. These studies suggest a role for NOX1 in maintaining the proliferative phenotype of some colon cancers and the potential of NOX1 as a therapeutic target in this disease. PMID:28330872

  19. NADPH Oxidase Is Internalized by Clathrin-coated Pits and Localizes to a Rab27A/B GTPase-regulated Secretory Compartment in Activated Macrophages*

    PubMed Central

    Ejlerskov, Patrick; Christensen, Dan Ploug; Beyaie, David; Burritt, James B.; Paclet, Marie-Helene; Gorlach, Agnes; van Deurs, Bo; Vilhardt, Frederik

    2012-01-01

    Here, we report that activation of different types of tissue macrophages, including microglia, by lipopolysaccharide (LPS) or GM-CSF stimulation correlates with the quantitative redistribution of NADPH oxidase (cyt b558) from the plasma membrane to an intracellular stimulus-responsive storage compartment. Cryo-immunogold labeling of gp91phox and CeCl3 cytochemistry showed the presence of gp91phox and oxidant production in numerous small (<100 nm) vesicles. Cell homogenization and sucrose gradient centrifugation in combination with transferrin-HRP/DAB ablation showed that more than half of cyt b558 is present in fractions devoid of endosomal markers, which is supported by morphological evidence to show that the cyt b558-containing compartment is distinct from endosomes or biosynthetic organelles. Streptolysin-O-mediated guanosine 5′-3-O-(thio)triphosphate loading of Ra2 microglia caused exocytosis of a major complement of cyt b558 under conditions where lysosomes or endosomes were not mobilized. We establish phagocytic particles and soluble mediators ATP, TNFα, and CD40L as physiological inducers of cyt b558 exocytosis to the cell surface, and by shRNA knockdown, we identify Rab27A/B as positive or negative regulators of vesicular mobilization to the phagosome or the cell surface, respectively. Exocytosis was followed by clathrin-dependent internalization of cyt b558, which could be blocked by a dominant negative mutant of the clathrin-coated pit-associated protein Eps15. Re-internalized cyt b558 did not reach lysosomes but associated with recycling endosomes and undefined vesicular elements. In conclusion, cyt b558 depends on clathrin for internalization, and in activated macrophages NADPH oxidase occupies a Rab27A/B-regulated secretory compartment, which allows rapid agonist-induced redistribution of superoxide production in the cell. PMID:22157766

  20. Diapocynin, a dimer of the NADPH oxidase inhibitor apocynin, reduces ROS production and prevents force loss in eccentrically contracting dystrophic muscle.

    PubMed

    Ismail, Hesham M; Scapozza, Leonardo; Ruegg, Urs T; Dorchies, Olivier M

    2014-01-01

    Elevation of intracellular Ca2+, excessive ROS production and increased phospholipase A2 activity contribute to the pathology in dystrophin-deficient muscle. Moreover, Ca2+, ROS and phospholipase A2, in particular iPLA2, are thought to potentiate each other in positive feedback loops. NADPH oxidases (NOX) have been considered as a major source of ROS in muscle and have been reported to be overexpressed in muscles of mdx mice. We report here on our investigations regarding the effect of diapocynin, a dimer of the commonly used NOX inhibitor apocynin, on the activity of iPLA2, Ca2+ handling and ROS generation in dystrophic myotubes. We also examined the effects of diapocynin on force production and recovery ability of isolated EDL muscles exposed to eccentric contractions in vitro, a damaging procedure to which dystrophic muscle is extremely sensitive. In dystrophic myotubes, diapocynin inhibited ROS production, abolished iPLA2 activity and reduced Ca2+ influx through stretch-activated and store-operated channels, two major pathways responsible for excessive Ca2+ entry in dystrophic muscle. Diapocynin also prevented force loss induced by eccentric contractions of mdx muscle close to the value of wild-type muscle and reduced membrane damage as seen by Procion orange dye uptake. These findings support the central role played by NOX-ROS in the pathogenic cascade leading to muscular dystrophy and suggest diapocynin as an effective NOX inhibitor that might be helpful for future therapeutic approaches.

  1. Regulating NETosis: Increasing pH Promotes NADPH Oxidase-Dependent NETosis

    PubMed Central

    Khan, Meraj A.; Philip, Lijy M.; Cheung, Guillaume; Vadakepeedika, Shawn; Grasemann, Hartmut; Sweezey, Neil; Palaniyar, Nades

    2018-01-01

    Neutrophils migrating from the blood (pH 7.35–7.45) into the surrounding tissues encounter changes in extracellular pH (pHe) conditions. Upon activation of NADPH oxidase 2 (Nox), neutrophils generate large amounts of H+ ions reducing the intracellular pH (pHi). Nevertheless, how extracellular pH regulates neutrophil extracellular trap (NET) formation (NETosis) is not clearly established. We hypothesized that increasing pH increases Nox-mediated production of reactive oxygen species (ROS) and neutrophil protease activity, stimulating NETosis. Here, we found that raising pHe (ranging from 6.6 to 7.8; every 0.2 units) increased pHi of both activated and resting neutrophils within 10–20 min (Seminaphtharhodafluor dual fluorescence measurements). Since Nox activity generates H+ ions, pHi is lower in neutrophils that are activated compared to resting. We also found that higher pH stimulated Nox-dependent ROS production (R123 generation; flow cytometry, plate reader assay, and imaging) during spontaneous and phorbol myristate acetate-induced NETosis (Sytox Green assays, immunoconfocal microscopy, and quantifying NETs). In neutrophils that are activated and not resting, higher pH stimulated histone H4 cleavage (Western blots) and NETosis. Raising pH increased Escherichia coli lipopolysaccharide-, Pseudomonas aeruginosa (Gram-negative)-, and Staphylococcus aureus (Gram-positive)-induced NETosis. Thus, higher pHe promoted Nox-dependent ROS production, protease activity, and NETosis; lower pH has the opposite effect. These studies provided mechanistic steps of pHe-mediated regulation of Nox-dependent NETosis. Raising pH either by sodium bicarbonate or Tris base (clinically known as Tris hydroxymethyl aminomethane, tromethamine, or THAM) increases NETosis. Each Tris molecule can bind 3H+ ions, whereas each bicarbonate HCO3− ion binds 1H+ ion. Therefore, the amount of Tris solution required to cause the same increase in pH level is less than that of equimolar

  2. Regulating NETosis: Increasing pH Promotes NADPH Oxidase-Dependent NETosis.

    PubMed

    Khan, Meraj A; Philip, Lijy M; Cheung, Guillaume; Vadakepeedika, Shawn; Grasemann, Hartmut; Sweezey, Neil; Palaniyar, Nades

    2018-01-01

    Neutrophils migrating from the blood (pH 7.35-7.45) into the surrounding tissues encounter changes in extracellular pH (pH e ) conditions. Upon activation of NADPH oxidase 2 (Nox), neutrophils generate large amounts of H + ions reducing the intracellular pH (pH i ). Nevertheless, how extracellular pH regulates neutrophil extracellular trap (NET) formation (NETosis) is not clearly established. We hypothesized that increasing pH increases Nox-mediated production of reactive oxygen species (ROS) and neutrophil protease activity, stimulating NETosis. Here, we found that raising pH e (ranging from 6.6 to 7.8; every 0.2 units) increased pH i of both activated and resting neutrophils within 10-20 min (Seminaphtharhodafluor dual fluorescence measurements). Since Nox activity generates H + ions, pH i is lower in neutrophils that are activated compared to resting. We also found that higher pH stimulated Nox-dependent ROS production (R123 generation; flow cytometry, plate reader assay, and imaging) during spontaneous and phorbol myristate acetate-induced NETosis (Sytox Green assays, immunoconfocal microscopy, and quantifying NETs). In neutrophils that are activated and not resting, higher pH stimulated histone H4 cleavage (Western blots) and NETosis. Raising pH increased Escherichia coli lipopolysaccharide-, Pseudomonas aeruginosa (Gram-negative)-, and Staphylococcus aureus (Gram-positive)-induced NETosis. Thus, higher pH e promoted Nox-dependent ROS production, protease activity, and NETosis; lower pH has the opposite effect. These studies provided mechanistic steps of pH e -mediated regulation of Nox-dependent NETosis. Raising pH either by sodium bicarbonate or Tris base (clinically known as Tris hydroxymethyl aminomethane, tromethamine, or THAM) increases NETosis. Each Tris molecule can bind 3H + ions, whereas each bicarbonate HCO3 - ion binds 1H + ion. Therefore, the amount of Tris solution required to cause the same increase in pH level is less than that of equimolar

  3. Advanced oxidation protein products sensitized the transient receptor potential vanilloid 1 via NADPH oxidase 1 and 4 to cause mechanical hyperalgesia.

    PubMed

    Ding, Ruoting; Jiang, Hui; Sun, Baihui; Wu, Xiaoliang; Li, Wei; Zhu, Siyuan; Liao, Congrui; Zhong, Zhaoming; Chen, Jianting

    2016-12-01

    Oxidative stress is a possible pathogenesis of hyperalgesia. Advanced oxidation protein products (AOPPs), a new family of oxidized protein compounds, have been considered as a novel marker of oxidative stress. However, the role of AOPPs in the mechanism of hyperalgesia remains unknown. Our study aims to investigate whether AOPPs have an effect on hyperalgesia and the possible underlying mechanisms. To identify the AOPPs involved, we induced hyperalgesia in rats by injecting complete Freund's adjuvant (CFA) in hindpaw. The level of plasma AOPPs in CFA-induced rats was 1.6-fold in comparison with what in normal rats (P<0.05). After intravenous injection of AOPPs-modified rat serum albumin (AOPPs-RSA) in Sprague-Dawley rats, the paw mechanical thresholds, measured by the electronic von Frey system, significantly declined. Immunofluorescence staining indicated that AOPPs increased expressions of NADPH oxidase 1 (Nox1), NADPH oxidase 4 (Nox4), transient receptor potential vanilloid 1 (TRPV1) and calcitonin gene-related peptide (CGRP) in the dorsal root ganglia (DRG) tissues. In-vitro studies were performed on primary DRG neurons which were obtained from both thoracic and lumbar DRG of rats. Results indicated that AOPPs triggered reactive oxygen species (ROS) production in DRG neurons, which were significantly abolished by ROS scavenger N-acetyl-l-cysteine (NAC) and small-interfering RNA (siRNA) silencing of Nox1 or Nox4. The expressions of Nox1, Nox4, TRPV1 and CGRP were significantly increased in AOPPs-induced DRG neurons. And relevant siRNA or inhibitors notably suppressed the expressions of these proteins and the calcium influxes in AOPPs-induced DRG neurons. In conclusion, AOPPs increased significantly in CFA-induced hyperalgesia rats and they activated Nox1/Nox4-ROS to sensitize TRPV1-dependent Ca2+ influx and CGRP release which led to inducing mechanical hyperalgesia. Copyright © 2016 The Authors. Published by Elsevier B.V. All rights reserved.

  4. Vascular Nox (NADPH Oxidase) Compartmentalization, Protein Hyperoxidation, and Endoplasmic Reticulum Stress Response in Hypertension.

    PubMed

    Camargo, Livia L; Harvey, Adam P; Rios, Francisco J; Tsiropoulou, Sofia; Da Silva, Renée de Nazaré Oliveira; Cao, Zhenbo; Graham, Delyth; McMaster, Claire; Burchmore, Richard J; Hartley, Richard C; Bulleid, Neil; Montezano, Augusto C; Touyz, Rhian M

    2018-07-01

    Vascular Nox (NADPH oxidase)-derived reactive oxygen species and endoplasmic reticulum (ER) stress have been implicated in hypertension. However, relationships between these processes are unclear. We hypothesized that Nox isoforms localize in a subcellular compartment-specific manner, contributing to oxidative and ER stress, which influence the oxidative proteome and vascular function in hypertension. Nox compartmentalization (cell fractionation), O 2 - (lucigenin), H 2 O 2 (amplex red), reversible protein oxidation (sulfenylation), irreversible protein oxidation (protein tyrosine phosphatase, peroxiredoxin oxidation), and ER stress (PERK [protein kinase RNA-like endoplasmic reticulum kinase], IRE1α [inositol-requiring enzyme 1], and phosphorylation/oxidation) were studied in spontaneously hypertensive rat (SHR) vascular smooth muscle cells (VSMCs). VSMC proliferation was measured by fluorescence-activated cell sorting, and vascular reactivity assessed in stroke-prone SHR arteries by myography. Noxs were downregulated by short interfering RNA and pharmacologically. In SHR, Noxs were localized in specific subcellular regions: Nox1 in plasma membrane and Nox4 in ER. In SHR, oxidative stress was associated with increased protein sulfenylation and hyperoxidation of protein tyrosine phosphatases and peroxiredoxins. Inhibition of Nox1 (NoxA1ds), Nox1/4 (GKT137831), and ER stress (4-phenylbutyric acid/tauroursodeoxycholic acid) normalized SHR vascular reactive oxygen species generation. GKT137831 reduced IRE1α sulfenylation and XBP1 (X-box binding protein 1) splicing in SHR. Increased VSMC proliferation in SHR was normalized by GKT137831, 4-phenylbutyric acid, and STF083010 (IRE1-XBP1 disruptor). Hypercontractility in the stroke-prone SHR was attenuated by 4-phenylbutyric acid. We demonstrate that protein hyperoxidation in hypertension is associated with oxidative and ER stress through upregulation of plasmalemmal-Nox1 and ER-Nox4. The IRE1-XBP1 pathway of the ER stress

  5. Role of redox signaling in the autonomous proliferative response of endothelial cells to hypoxia.

    PubMed

    Schäfer, M; Schäfer, C; Ewald, N; Piper, H M; Noll, Th

    2003-05-16

    Endothelial cells exhibit an autonomous proliferative response to hypoxia, independent of paracrine effectors. In cultured endothelial cells of porcine aorta, we analyzed the signaling of this response, with a focus on the roles of redox signaling and the MEK/ERK pathway. Transient hypoxia (1 hour) stimulated proliferation by 61+/-4% (n=16; P<0.05 versus control), quantified after 24 hours normoxic postincubation. Hypoxia induced an activation of ERK2 and of NAD(P)H oxidase and a burst of reactive oxygen species (ROS), determined by DCF fluorescence. To inhibit the MEK/ERK pathway, we used PD 98059 (PD, 20 micromol/L); to downregulate NAD(P)H oxidase, we applied p22phox antisense oligonucleotides; and to inhibit mitochondrial ROS generation, we used the ubiquinone derivate mitoQ (MQ, 10 micromol/L). All three inhibitions suppressed the proliferative response: PD inhibited NAD(P)H oxidase activation; p22phox antisense transfection did not inhibit ERK2 activation, but suppressed ROS production; and MQ inhibited ERK2 activation and ROS production. The autonomous proliferative response depends on the MEK/ERK pathway and redox signaling steps upstream and downstream of ERK. Located upstream is ROS generation by mitochondria, downstream is NAD(P)H oxidase.

  6. JNK and NADPH Oxidase Involved in Fluoride-Induced Oxidative Stress in BV-2 Microglia Cells

    PubMed Central

    Yan, Ling; Liu, Shengnan; Wang, Chen; Wang, Fei; Song, Yingli; Yan, Nan; Xi, Shuhua; Liu, Ziyou; Sun, Guifan

    2013-01-01

    Excessive fluoride may cause central nervous system (CNS) dysfunction, and oxidative stress is a recognized mode of action of fluoride toxicity. In CNS, activated microglial cells can release more reactive oxygen species (ROS), and NADPH oxidase (NOX) is the major enzyme for the production of extracellular superoxide in microglia. ROS have been characterized as an important secondary messenger and modulator for various mammalian intracellular signaling pathways, including the MAPK pathways. In this study we examined ROS production and TNF-α, IL-1β inflammatory cytokines releasing, and the expression of MAPKs in BV-2 microglia cells treated with fluoride. We found that fluoride increased JNK phosphorylation level of BV-2 cells and pretreatment with JNK inhibitor SP600125 markedly reduced the levels of intracellular O2 ·− and NO. NOX inhibitor apocynin and iNOS inhibitor SMT dramatically decreased NaF-induced ROS and NO generations, respectively. Antioxidant melatonin (MEL) resulted in a reduction in JNK phosphorylation in fluoride-stimulated BV-2 microglia. The results confirmed that NOX and iNOS played an important role in fluoride inducing oxidative stress and NO production and JNK took part in the oxidative stress induced by fluoride and meanwhile also could be activated by ROS in fluoride-treated BV-2 cells. PMID:24072958

  7. Identification and Characterization of Sclerotinia sclerotiorum NADPH Oxidases▿†

    PubMed Central

    Kim, Hyo-jin; Chen, Changbin; Kabbage, Mehdi; Dickman, Martin B.

    2011-01-01

    Numerous studies have shown both the detrimental and beneficial effects of reactive oxygen species (ROS) in animals, plants, and fungi. These organisms utilize controlled generation of ROS for signaling, pathogenicity, and development. Here, we show that ROS are essential for the pathogenic development of Sclerotinia sclerotiorum, an economically important fungal pathogen with a broad host range. Based on the organism's completed genome sequence, we identified two S. sclerotiorum NADPH oxidases (SsNox1 and SsNox2), which presumably are involved in ROS generation. RNA interference (RNAi) was used to examine the function of SsNox1 and SsNox2. Silencing of SsNox1 expression indicated a central role for this enzyme in both virulence and pathogenic (sclerotial) development, while inactivation of the SsNox2 gene resulted in limited sclerotial development, but the organism remained fully pathogenic. ΔSsnox1 strains had reduced ROS levels, were unable to develop sclerotia, and unexpectedly correlated with significantly reduced oxalate production. These results are in accordance with previous observations indicating that fungal NADPH oxidases are required for pathogenic development and are consistent with the importance of ROS regulation in the successful pathogenesis of S. sclerotiorum. PMID:21890677

  8. Leptin promotes neointima formation and smooth muscle cell proliferation via NADPH oxidase activation and signalling in caveolin-rich microdomains.

    PubMed

    Schroeter, Marco R; Leifheit-Nestler, Maren; Hubert, Astrid; Schumann, Bettina; Glückermann, Roland; Eschholz, Norman; Krüger, Nenja; Lutz, Susanne; Hasenfuss, Gerd; Konstantinides, Stavros; Schäfer, Katrin

    2013-08-01

    Apolipoprotein E (apoE) may act as a vasculoprotective factor by promoting plasma lipid clearance and cholesterol efflux. Moreover, apoE accumulates at sites of vascular injury and modulates the effect of growth factors on smooth muscle cells (SMCs). Experimental data suggested that hypothalamic apoE expression is reduced in obesity and associated with leptin resistance. In this study, we examined the role of apoE in mediating the effects of leptin on vascular lesion formation. Leptin was administered to apoE knockout (apoE-/-) mice via osmotic pumps to increase its circulating levels. Morphometric analysis revealed that leptin did not alter neointima formation and failed to increase α-actin- or PCNA-immunopositive SMCs after vascular injury. Similar findings were obtained after analysis of atherosclerotic lesions. Comparison of apoE-/-, wild-type, or LDL receptor-/- mice and functional analyses in aortic SMCs from WT or apoE-/- mice or human arterial SMCs after treatment with small interfering (si)RNA or heparinase revealed that leptin requires the presence of apoE, expressed, secreted and bound to the cell surface, to fully activate leptin receptor signalling and to promote SMC proliferation and neointima formation. Mechanistically, leptin induced the phosphorylation and membrane translocation of caveolin (cav)-1, and apoE down-regulation or caveolae disruption inhibited the leptin-induced p47phox activation, ROS formation and SMC proliferation. Finally, leptin failed to increase neointima formation in mice lacking cav-1. Our findings suggest that apoE mediates the effects of leptin on vascular lesion formation by stabilizing cav-1-enriched cell membrane microdomains in SMCs, thus allowing NADPH oxidase assembly and ROS-mediated mitogenic signalling.

  9. Expression and functional significance of NADPH oxidase 5 (Nox5) and its splice variants in human blood vessels

    PubMed Central

    Pandey, Deepesh; Patel, Anand; Patel, Vijay; Chen, Feng; Qian, Jin; Wang, Yusi; Barman, Scott A.; Venema, Richard C.; Stepp, David W.; Daniel Rudic, R.

    2012-01-01

    The expression and functional significance of NADPH oxidase 5 (Nox5) and its five isoforms in vascular cells is poorly understood. The goal of this study was to determine whether Nox5-α, -β, -δ, -γ, and -ε (short) are expressed in human blood vessels and evaluate their respective functions. Nox5 mRNA and protein were detected in human blood vessels, cultured human vascular smooth muscle (HVSMC) and endothelium, but not fibroblasts. The most abundant isoforms were α and β, whereas δ and γ were not detected. Nox5-α and -β produced reactive oxygen species (ROS), but -δ, -γ, and -ε were not catalytically active. Coexpression of the active Nox5 isoforms with inactive Nox5 variants suppressed ROS production, and coimmunoprecipitation revealed that Nox5-β binds the inactive ε variant, which may account for reduced ROS production. In HVSMC, angiotensin II, endothelin-1 and TNF-α increased endogenous Nox5 mRNA levels, while adenovirus-mediated overexpression of Nox5 promoted p38 MAPK, JAK2, JNK, and ERK1/2 phosphorylation in endothelial cells (EC), but only increased ERK1/2 phosphorylation in HVSMC. At higher levels of Nox5, there was evidence of increased apoptosis in EC, but not in HVSMC, as detected by the presence of cleaved caspase-3 and cleaved poly(ADP-ribose)polymerase. Although catalytically inactive, Nox5-ε potently activated ERK in HVSMC, and increased expression of Nox5-ε promoted HVSMC proliferation. Nox5 is expressed in human blood vessels. The Nox5-α and -β splice variants are the major isoforms that are expressed and the only variants capable of ROS production. Nox5-ε can inhibit Nox5 activity and activate ERK and HVSMC proliferation. PMID:22427510

  10. Direct Activation of NADPH Oxidase 2 by 2-Deoxyribose-1-Phosphate Triggers Nuclear Factor Kappa B-Dependent Angiogenesis

    PubMed Central

    Vara, Dina; Watt, Joanna M.; Fortunato, Tiago M.; Mellor, Harry; Burgess, Matthew; Wicks, Kate; Mace, Kimberly; Reeksting, Shaun; Lubben, Anneke; Wheeler-Jones, Caroline P.D.

    2018-01-01

    Abstract Aims: Deoxyribose-1-phosphate (dRP) is a proangiogenic paracrine stimulus released by cancer cells, platelets, and macrophages and acting on endothelial cells. The objective of this study was to clarify how dRP stimulates angiogenic responses in human endothelial cells. Results: Live cell imaging, electron paramagnetic resonance, pull-down of dRP-interacting proteins, followed by immunoblotting, gene silencing of different NADPH oxidases (NOXs), and their regulatory cosubunits by small interfering RNA (siRNA) transfection, and experiments with inhibitors of the sugar transporter glucose transporter 1 (GLUT1) were utilized to demonstrate that dRP acts intracellularly by directly activating the endothelial NOX2 complex, but not NOX4. Increased reactive oxygen species generation in response to NOX2 activity leads to redox-dependent activation of the transcription factor nuclear factor kappa B (NF-κB), which, in turn, induces vascular endothelial growth factor receptor 2 (VEGFR2) upregulation. Using endothelial tube formation assays, gene silencing by siRNA, and antibody-based receptor inhibition, we demonstrate that the activation of NF-κB and VEGFR2 is necessary for the angiogenic responses elicited by dRP. The upregulation of VEGFR2 and NOX2-dependent stimulation of angiogenesis by dRP were confirmed in excisional wound and Matrigel plug vascularization assays in vivo using NOX2−/− mice. Innovation: For the first time, we demonstrate that dRP acts intracellularly and stimulates superoxide anion generation by direct binding and activation of the NOX2 enzymatic complex. Conclusions: This study describes a novel molecular mechanism underlying the proangiogenic activity of dRP, which involves the sequential activation of NOX2 and NF-κB and upregulation of VEGFR2. Antioxid. Redox Signal. 28, 110–130. PMID:28793782

  11. NADPH oxidase 4 induces cardiac fibrosis and hypertrophy through activating Akt/mTOR and NFκB signaling pathways.

    PubMed

    Zhao, Qingwei David; Viswanadhapalli, Suryavathi; Williams, Paul; Shi, Qian; Tan, Chunyan; Yi, Xiaolan; Bhandari, Basant; Abboud, Hanna E

    2015-02-17

    NADPH oxidase 4 (Nox4) has been implicated in cardiac remodeling, but its precise role in cardiac injury remains controversial. Furthermore, little is known about the downstream effector signaling pathways activated by Nox4-derived reactive oxygen species in the myocardium. We investigated the role of Nox4 and Nox4-associated signaling pathways in the development of cardiac remodeling. Cardiac-specific human Nox4 transgenic mice (c-hNox4Tg) were generated. Four groups of mice were studied: (1) control mice, littermates that are negative for hNox4 transgene but Cre positive; (2) c-hNox4 Tg mice; (3) angiotensin II (AngII)-infused control mice; and (4) c-hNox4Tg mice infused with AngII. The c-hNox4Tg mice exhibited an ≈10-fold increase in Nox4 protein expression and an 8-fold increase in the production of reactive oxygen species, and manifested cardiac interstitial fibrosis. AngII infusion to control mice increased cardiac Nox4 expression and induced fibrosis and hypertrophy. The Tg mice receiving AngII exhibited more advanced cardiac remodeling and robust elevation in Nox4 expression, indicating that AngII worsens cardiac injury, at least in part by enhancing Nox4 expression. Moreover, hNox4 transgene and AngII infusion induced the expression of cardiac fetal genes and activated the Akt-mTOR and NFκB signaling pathways. Treatment of AngII-infused c-hNox4Tg mice with GKT137831, a Nox4/Nox1 inhibitor, abolished the increase in oxidative stress, suppressed the Akt-mTOR and NFκB signaling pathways, and attenuated cardiac remodeling. Upregulation of Nox4 in the myocardium causes cardiac remodeling through activating Akt-mTOR and NFκB signaling pathways. Inhibition of Nox4 has therapeutic potential to treat cardiac remodeling. © 2015 American Heart Association, Inc.

  12. NADPH Oxidase 4 Induces Cardiac Fibrosis and Hypertrophy through Activating Akt/mTOR and NFκB Signaling Pathways

    PubMed Central

    Zhao, Qingwei David; Viswanadhapalli, Suryavathi; Williams, Paul; Shi, Qian; Tan, Chunyan; Yi, Xiaolan; Bhandari, Basant; Abboud, Hanna E.

    2015-01-01

    Background NADPH oxidase 4 (Nox4) has been implicated in cardiac remodeling, but its precise role in cardiac injury remains controversial. Furthermore, little is known about the downstream effector signaling pathways activated by Nox4-derived ROS in the myocardium. We investigated the role of Nox4 and Nox4 associated signaling pathways in the development of cardiac remodeling. Methods and Results Cardiac-specific human Nox4 transgenic mice (c-hNox4Tg) were generated. Four groups of mice were studied: 1) control mice (CTL): littermates that are negative for hNox4 transgene but Cre positive; 2) c-hNox4 Tg mice; 3) angiotensin II (AngII)-infused CTL mice and 4) c-hNox4Tg mice infused with AngII. The c-hNox4Tg mice exhibited approximately 10-fold increase in Nox4 protein expression and 8-fold increase in the production of reactive oxygen species, and manifested cardiac interstitial fibrosis. AngII-infusion to CTL mice increased cardiac Nox4 expression and induced fibrosis and hypertrophy. The Tg mice receiving AngII exhibited more advanced cardiac remodeling and robust elevation in Nox4 expression, indicating that AngII worsens cardiac injury, at least partially by enhancing Nox4 expression. Moreover, hNox4 transgene and/or AngII-infusion induced the expression of cardiac fetal genes and activated the Akt-mTOR and NFκB signaling pathways. Treatment of AngII-infused c-hNox4Tg mice with GKT137831, a Nox4/Nox1 inhibitor, abolished the increase in oxidative stress, suppressed Akt-mTOR and NFκB signaling pathway and attenuated cardiac remodeling. Conclusion Upregulation of Nox4 in the myocardium causes cardiac remodeling through activating Akt-mTOR and NFκB signaling pathways. Inhibition of Nox4 has therapeutic potential to treat cardiac remodeling. PMID:25589557

  13. Nadph oxidase regulates alveolar epithelial sodium channel activity and lung fluid balance in vivo via O⁻₂ signaling.

    PubMed

    Goodson, Preston; Kumar, Amrita; Jain, Lucky; Kundu, Kousik; Murthy, Niren; Koval, Michael; Helms, My N

    2012-02-15

    To define roles for reactive oxygen species (ROS) and epithelial sodium channel (ENaC) in maintaining lung fluid balance in vivo, we used two novel whole animal imaging approaches. Live X-ray fluoroscopy enabled quantification of air space fluid content of C57BL/6J mouse lungs challenged by intratracheal (IT) instillation of saline; results were confirmed by using conventional lung wet-to-dry weight ratios and Evans blue as measures of pulmonary edema. Visualization and quantification of ROS produced in lungs was performed in mice that had been administered a redox-sensitive dye, hydro-Cy7, by IT instillation. We found that inhibition of NADPH oxidase with a Rac-1 inhibitor, NSC23766, resulted in alveolar flooding, which correlated with a decrease in lung ROS production in vivo. Consistent with a role for Nox2 in alveolar fluid balance, Nox2(-/-) mice showed increased retention of air space fluid compared with wild-type controls. Interestingly, fluoroscopic analysis of C57BL/6J lungs IT instilled with LPS showed an acute stimulation of lung fluid clearance and ROS production in vivo that was abrogated by the ROS scavenger tetramethylpiperidine-N-oxyl (TEMPO). Acute application of LPS increased the activity of 20 pS nonselective ENaC channels in rat type 1 cells; the average number of channel and single-channel open probability (NPo) increased from 0.14 ± 0.04 to 0.62 ± 0.23. Application of TEMPO to the same cell-attached recording caused an immediate significant decrease in ENaC NPo to 0.04 ± 0.03. These data demonstrate that, in vivo, ROS has the capacity to stimulate lung fluid clearance by increasing ENaC activity.

  14. Impact of Cyanidin-3-Glucoside on Glycated LDL-Induced NADPH Oxidase Activation, Mitochondrial Dysfunction and Cell Viability in Cultured Vascular Endothelial Cells

    PubMed Central

    Xie, Xueping; Zhao, Ruozhi; Shen, Garry X.

    2012-01-01

    Elevated levels of glycated low density lipoprotein (glyLDL) are frequently detected in diabetic patients. Previous studies demonstrated that glyLDL increased the production of reactive oxygen species (ROS), activated NADPH oxidase (NOX) and suppressed mitochondrial electron transport chain (mETC) enzyme activities in vascular endothelial cells (EC). The present study examined the effects of cyanidin-3-glucoside (C3G), a type of anthocyanin abundant in dark-skinned berries, on glyLDL-induced ROS production, NOX activation and mETC enzyme activity in porcine aortic EC (PAEC). Co-treatment of C3G prevented glyLDL-induced upregulation of NOX4 and intracellular superoxide production in EC. C3G normalized glyLDL-induced inhibition on the enzyme activities of mETC Complex I and III, as well as the abundances of NADH dehydrogenase 1 in Complex I and cytochrome b in Complex III in EC. Blocking antibody for the receptor of advanced glycation end products (RAGE) prevented glyLDL-induced changes in NOX and mETC enzymes. Combination of C3G and RAGE antibody did not significantly enhance glyLDL-induced inhibition of NOX or mETC enzymes. C3G reduced glyLDL-induced RAGE expression with the presence of RAGE antibody. C3G prevented prolonged incubation with the glyLDL-induced decrease in cell viability and the imbalance between key regulators for cell viability (cleaved caspase 3 and B cell Lyphoma-2) in EC. The findings suggest that RAGE plays an important role in glyLDL-induced oxidative stress in vascular EC. C3G may prevent glyLDL-induced NOX activation, the impairment of mETC enzymes and cell viability in cultured vascular EC. PMID:23443099

  15. Impact of cyanidin-3-glucoside on glycated LDL-induced NADPH oxidase activation, mitochondrial dysfunction and cell viability in cultured vascular endothelial cells.

    PubMed

    Xie, Xueping; Zhao, Ruozhi; Shen, Garry X

    2012-11-27

    Elevated levels of glycated low density lipoprotein (glyLDL) are frequently detected in diabetic patients. Previous studies demonstrated that glyLDL increased the production of reactive oxygen species (ROS), activated NADPH oxidase (NOX) and suppressed mitochondrial electron transport chain (mETC) enzyme activities in vascular endothelial cells (EC). The present study examined the effects of cyanidin-3-glucoside (C3G), a type of anthocyanin abundant in dark-skinned berries, on glyLDL-induced ROS production, NOX activation and mETC enzyme activity in porcine aortic EC (PAEC). Co-treatment of C3G prevented glyLDL-induced upregulation of NOX4 and intracellular superoxide production in EC. C3G normalized glyLDL-induced inhibition on the enzyme activities of mETC Complex I and III, as well as the abundances of NADH dehydrogenase 1 in Complex I and cytochrome b in Complex III in EC. Blocking antibody for the receptor of advanced glycation end products (RAGE) prevented glyLDL-induced changes in NOX and mETC enzymes. Combination of C3G and RAGE antibody did not significantly enhance glyLDL-induced inhibition of NOX or mETC enzymes. C3G reduced glyLDL-induced RAGE expression with the presence of RAGE antibody. C3G prevented prolonged incubation with the glyLDL-induced decrease in cell viability and the imbalance between key regulators for cell viability (cleaved caspase 3 and B cell Lyphoma-2) in EC. The findings suggest that RAGE plays an important role in glyLDL-induced oxidative stress in vascular EC. C3G may prevent glyLDL-induced NOX activation, the impairment of mETC enzymes and cell viability in cultured vascular EC.

  16. The S100A8/A9 protein as a partner for the cytosolic factors of NADPH oxidase activation in neutrophils.

    PubMed

    Doussiere, Jacques; Bouzidi, Farid; Vignais, Pierre V

    2002-07-01

    In a previous study, the S100A8/A9 protein, a Ca2+- and arachidonic acid-binding protein, abundant in neutrophil cytosol, was found to potentiate the activation of the redox component of the O2- generating oxidase in neutrophils, namely the membrane-bound flavocytochrome b, by the cytosolic phox proteins p67phox, p47phox and Rac (Doussière J., Bouzidi F. and Vignais P.V. (2001) Biochem. Biophys. Res. Commun.285, 1317-1320). This led us to check by immunoprecipitation and protein fractionation whether the cytosolic phox proteins could bind to S100A8/A9. Following incubation of a cytosolic extract from nonactivated bovine neutrophil with protein A-Sepharose bound to anti-p67phox antibodies, the recovered immunoprecipitate contained the S100 protein, p47phox and p67phox. Cytosolic protein fractionation comprised two successive chromatographic steps on hydroxyapatite and DEAE cellulose, followed by isoelectric focusing. The S100A8/A9 heterodimeric protein comigrated with the cytosolic phox proteins, and more particularly with p67phox and Rac2, whereas the isolated S100A8 protein displayed a tendancy to bind to p47phox. Using a semirecombinant cell-free system of oxidase activation consisting of recombinant p67phox, p47phox and Rac2, neutrophil membranes and arachidonic acid, we found that the S100A8/A9-dependent increase in the elicited oxidase activity corresponded to an increase in the turnover of the membrane-bound flavocytochrome b, but not to a change of affinity for NADPH or O2. In the absence of S100A8/A9, oxidase activation departed from michaelian kinetics above a critical threshold concentration of cytosolic phox proteins. Addition of S100A8/A9 to the cell-free system rendered the kinetics fully michaelian. The propensity of S100A8/A9 to bind the cytosolic phox proteins, and the effects of S100A8/A9 on the kinetics of oxidase activation, suggest that S100A8/A9 might be a scaffold protein for the cytosolic phox proteins or might help to deliver arachidonic

  17. NADPH oxidase 4-derived superoxide mediates flow-stimulated NKCC2 activity in thick ascending limbs.

    PubMed

    Saez, Fara; Hong, Nancy J; Garvin, Jeffrey L

    2018-05-01

    Luminal flow augments Na + reabsorption in the thick ascending limb more than can be explained by increased ion delivery. This segment reabsorbs 30% of the filtered load of Na + , playing a key role in its homeostasis. Whether flow elevations enhance Na + -K + -2Cl - cotransporter (NKCC2) activity and the second messenger involved are unknown. We hypothesized that raising luminal flow augments NKCC2 activity by enhancing superoxide ([Formula: see text]) production by NADPH oxidase 4 (NOX4). NKCC2 activity was measured in thick ascending limbs perfused at either 5 or 20 nl/min with and without inhibitors of [Formula: see text] production. Raising luminal flow from 5 to 20 nl/min enhanced NKCC2 activity from 4.8 ± 0.9 to 6.3 ± 1.2 arbitrary fluorescent units (AFU)/s. Maintaining flow at 5 nl/min did not alter NKCC2 activity. The superoxide dismutase mimetic manganese (III) tetrakis (4-benzoic acid) porphyrin chloride blunted NKCC2 activity from 3.5 ± 0.4 to 2.5 ± 0.2 AFU/s when flow was 20 nl/min but not 5 nl/min. When flow was 20 nl/min, NKCC2 activity showed no change with time. The selective NOX1/4 inhibitor GKT-137831 blunted NKCC2 activity when thick ascending limbs were perfused at 20 nl/min from 7.2 ± 1.1 to 4.5 ± 0.8 AFU/s but not at 5 nl/min. The inhibitor also prevented luminal flow from elevating [Formula: see text] production. Allopurinol, a xanthine oxidase inhibitor, had no effect on NKCC2 activity when flow was 20 nl/min. Tetanus toxin prevents flow-induced stimulation of NKCC2 activity. We conclude that elevations in luminal flow enhance NaCl reabsorption in thick ascending limbs by stimulating NKCC2 via NOX4 activation and increased [Formula: see text]. NKCC2 activation is primarily the result of insertion of new transporters in the membrane.

  18. Attenuation of brain edema and spatial learning deficits by the inhibition of NADPH oxidase activity using apocynin following diffuse traumatic brain injury in rats.

    PubMed

    Song, Si-Xin; Gao, Jun-Ling; Wang, Kai-Jie; Li, Ran; Tian, Yan-Xia; Wei, Jian-Qiang; Cui, Jian-Zhong

    2013-01-01

    Diffuse brain injury (DBI) is a leading cause of mortality and disability among young individuals and adults worldwide. In specific cases, DBI is associated with permanent spatial learning dysfunction and motor deficits due to primary and secondary brain damage. Nicotinamide adenine dinucleotide phosphate (NADPH) oxidase (NOX) is a major complex that produces reactive oxygen species (ROS) during the ischemic period. The complex aggravates brain damage and cell death following ischemia/reperfusion injury; however, its role in DBI remains unclear. The present study aimed to investigate the hypothesis that levels of NOX2 (a catalytic subunit of NOX) protein expression and the activation of NOX are enhanced following DBI induction in rats and are involved in aggravating secondary brain damage. A rat model of DBI was created using a modified weight-drop device. Our results demonstrated that NOX2 protein expression and NOX activity were enhanced in the CA1 subfield of the hippocampus at 48 and 72 h following DBI induction. Treatment with apocynin (50 mg/kg body weight), a specific inhibitor of NOX, injected intraperitoneally 30 min prior to DBI significantly attenuated NOX2 protein expression and NOX activation. Moreover, treatment with apocynin reduced brain edema and improved spatial learning function assessed using the Morris water maze. These results reveal that treatment with apocynin may provide a new neuroprotective therapeutic strategy against DBI by diminishing the upregulation of NOX2 protein and NOX activity.

  19. Calcium sequestration by fungal melanin inhibits calcium-calmodulin signalling to prevent LC3-associated phagocytosis.

    PubMed

    Kyrmizi, Irene; Ferreira, Helena; Carvalho, Agostinho; Figueroa, Julio Alberto Landero; Zarmpas, Pavlos; Cunha, Cristina; Akoumianaki, Tonia; Stylianou, Kostas; Deepe, George S; Samonis, George; Lacerda, João F; Campos, António; Kontoyiannis, Dimitrios P; Mihalopoulos, Nikolaos; Kwon-Chung, Kyung J; El-Benna, Jamel; Valsecchi, Isabel; Beauvais, Anne; Brakhage, Axel A; Neves, Nuno M; Latge, Jean-Paul; Chamilos, Georgios

    2018-05-30

    LC3-associated phagocytosis (LAP) is a non-canonical autophagy pathway regulated by Rubicon, with an emerging role in immune homeostasis and antifungal host defence. Aspergillus cell wall melanin protects conidia (spores) from killing by phagocytes and promotes pathogenicity through blocking nicotinamide adenine dinucleotide phosphate (NADPH) oxidase-dependent activation of LAP. However, the signalling regulating LAP upstream of Rubicon and the mechanism of melanin-induced inhibition of this pathway remain incompletely understood. Herein, we identify a Ca 2+ signalling pathway that depends on intracellular Ca 2+ sources from endoplasmic reticulum, endoplasmic reticulum-phagosome communication, Ca 2+ release from phagosome lumen and calmodulin (CaM) recruitment, as a master regulator of Rubicon, the phagocyte NADPH oxidase NOX2 and other molecular components of LAP. Furthermore, we provide genetic evidence for the physiological importance of Ca 2+ -CaM signalling in aspergillosis. Finally, we demonstrate that Ca 2+ sequestration by Aspergillus melanin inside the phagosome abrogates activation of Ca 2+ -CaM signalling to inhibit LAP. These findings reveal the important role of Ca 2+ -CaM signalling in antifungal immunity and identify an immunological function of Ca 2+ binding by melanin pigments with broad physiological implications beyond fungal disease pathogenesis.

  20. β-Adrenergic receptors desensitization is not involved in exercise-induced cardiac fatigue: NADPH oxidase-induced oxidative stress as a new trigger.

    PubMed

    Vitiello, Damien; Boissière, Julien; Doucende, Grégory; Gayrard, Sandrine; Polge, Anne; Faure, Patrice; Goux, Aurélie; Tanguy, Stéphane; Obert, Philippe; Reboul, Cyril; Nottin, Stéphane

    2011-11-01

    Prolonged strenuous exercise (PSE) induces transient left ventricular (LV) dysfunction. Previous studies suggest that β-adrenergic pathway desensitization could be involved in this phenomenon, but it remains to be confirmed. Moreover, other underlying mechanisms involving oxidative stress have been recently proposed. The present study aimed to evaluate the involvement of both the β-adrenergic pathway and NADPH oxidase (Nox) enzyme-induced oxidative stress in myocardial dysfunction in rats following PSE. Rats were divided into 4 groups: controls (Ctrl), 4-h exercised on treadmill (PSE), and 2 groups in which Nox enzyme was inhibited with apocynin treatment (Ctrl APO and PSE APO, respectively). We evaluated cardiac function in vivo and ex vivo during basal conditions and isoproterenol stress. GSH/GSSG ratio, cardiac troponin I (cTnI) release, and lipid peroxidation (MDA) were evaluated. PSE induced a decrease in LV developed pressure, intrinsic myocardial contractility, and relaxation associated with an increase in plasma cTnI release. Our in vivo and ex vivo results demonstrated no differences in myocardial response to isoproterenol and of effective dose 50 between control and PSE rats. Interestingly, the LV dysfunction was reversed by apocynin treatment. Moreover, apocynin prevented cellular oxidation [GSH/GSSG ratio: PSE APO rats vs. PSE rats in arbitrary units (au): 1.98 ± 0.07 vs. 1.35 ± 0.10; P < 0.001]. However, no differences in MDA were observed between groups. These data suggest that myocardial dysfunction observed after PSE was not due to β-adrenergic receptor desensitization but could be due to a signaling oxidative stress from the Nox enzyme.

  1. Lysyl oxidase propeptide inhibits smooth muscle cell signaling and proliferation

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

    Hurtado, Paola A.; Vora, Siddharth; Sume, Siddika Selva

    2008-02-01

    Lysyl oxidase is required for the normal biosynthesis and maturation of collagen and elastin. It is expressed by vascular smooth muscle cells, and its increased expression has been previously found in atherosclerosis and in models of balloon angioplasty. The lysyl oxidase propeptide (LOX-PP) has more recently been found to have biological activity as a tumor suppressor, and it inhibits Erk1/2 Map kinase activation. We reasoned that LOX-PP may have functions in normal non-transformed cells. We, therefore, investigated its effects on smooth muscle cells, focusing on important biological processes mediated by Erk1/2-dependent signaling pathways including proliferation and matrix metalloproteinase-9 (MMP-9) expression.more » In addition, we investigated whether evidence for accumulation of LOX-PP could be found in vivo in a femoral artery injury model. Recombinant LOX-PP was expressed and purified, and was found to inhibit primary rat aorta smooth muscle cell proliferation and DNA synthesis by more than 50%. TNF-{alpha}-stimulated MMP-9 expression and Erk1/2 activation were both significantly inhibited by LOX-PP. Immunohistochemistry studies carried out with affinity purified anti-LOX-PP antibody showed that LOX-PP epitopes were expressed at elevated levels in vascular lesions of injured arteries. These novel data suggest that LOX-PP may provide a feedback control mechanism that serves to inhibit properties associated with the development of vascular pathology.« less

  2. Time dependent inhibition of xanthine oxidase in irradiated solutions of folic acid, aminopterin and methotrexate

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

    Robinson, K.; Pilot, T.F.; Meany, J.E.

    1990-01-01

    The xanthine oxidase catalyzed oxidation of hypoxanthine was followed by monitoring the formation of uric acid at 290 nm. Inhibition of xanthine oxidase occurs in aqueous solutions of folic acid methotrexate and aminopterin. These compounds are known to dissociate upon exposure to ultraviolet light resulting in the formation of their respective 6-formylpteridine derivatives. The relative rates of dissociation were monitored spectrophotometrically by determining the absorbance of their 2,4-dinitrophenylhydrazine derivatives at 500 nm. When aqueous solutions of folic acid, aminopterin and methotrexate were exposed to uv light, a direct correlation was observed between the concentrations of the 6-formylpteridine derivatives existing inmore » solution and the ability of these solutions to inhibit xanthine oxidase. The relative potency of the respective photolysis products were estimated.« less

  3. NADPH Oxidase 1 Modulates WNT and NOTCH1 Signaling To Control the Fate of Proliferative Progenitor Cells in the Colon▿

    PubMed Central

    Coant, Nicolas; Ben Mkaddem, Sanae; Pedruzzi, Eric; Guichard, Cécile; Tréton, Xavier; Ducroc, Robert; Freund, Jean-Noel; Cazals-Hatem, Dominique; Bouhnik, Yoram; Woerther, Paul-Louis; Skurnik, David; Grodet, Alain; Fay, Michèle; Biard, Denis; Lesuffleur, Thécla; Deffert, Christine; Moreau, Richard; Groyer, André; Krause, Karl-Heinz; Daniel, Fanny; Ogier-Denis, Eric

    2010-01-01

    The homeostatic self-renewal of the colonic epithelium requires coordinated regulation of the canonical Wnt/β-catenin and Notch signaling pathways to control proliferation and lineage commitment of multipotent stem cells. However, the molecular mechanisms by which the Wnt/β-catenin and Notch1 pathways interplay in controlling cell proliferation and fate in the colon are poorly understood. Here we show that NADPH oxidase 1 (NOX1), a reactive oxygen species (ROS)-producing oxidase that is highly expressed in colonic epithelial cells, is a pivotal determinant of cell proliferation and fate that integrates Wnt/β-catenin and Notch1 signals. NOX1-deficient mice reveal a massive conversion of progenitor cells into postmitotic goblet cells at the cost of colonocytes due to the concerted repression of phosphatidylinositol 3-kinase (PI3K)/AKT/Wnt/β-catenin and Notch1 signaling. This conversion correlates with the following: (i) the redox-dependent activation of the dual phosphatase PTEN, causing the inactivation of the Wnt pathway effector β-catenin, and (ii) the downregulation of Notch1 signaling that provokes derepression of mouse atonal homolog 1 (Math1) expression. We conclude that NOX1 controls the balance between goblet and absorptive cell types in the colon by coordinately modulating PI3K/AKT/Wnt/β-catenin and Notch1 signaling. This finding provides the molecular basis for the role of NOX1 in cell proliferation and postmitotic differentiation. PMID:20351171

  4. Substance P enhances microglial density in the substantia nigra through neurokinin-1 receptor/NADPH oxidase-mediated chemotaxis in mice.

    PubMed

    Wang, Qingshan; Oyarzabal, Esteban; Wilson, Belinda; Qian, Li; Hong, Jau-Shyong

    2015-10-01

    The distribution of microglia varies greatly throughout the brain. The substantia nigra (SN) contains the highest density of microglia among different brain regions. However, the mechanism underlying this uneven distribution remains unclear. Substance P (SP) is a potent proinflammatory neuropeptide with high concentrations in the SN. We recently demonstrated that SP can regulate nigral microglial activity. In the present study, we further investigated the involvement of SP in modulating nigral microglial density in postnatal developing mice. Nigral microglial density was quantified in wild-type (WT) and SP-deficient mice from postnatal day 1 (P1) to P30. SP was detected at high levels in the SN as early as P1 and microglial density did not peak until around P30 in WT mice. SP-deficient mice (TAC1(-/-)) had a significant reduction in nigral microglial density. No differences in the ability of microglia to proliferate were observed between TAC1(-/-) and WT mice, suggesting that SP may alter microglial density through chemotaxic recruitment. SP was confirmed to dose-dependently attract microglia using a trans-well culture system. Mechanistic studies revealed that both the SP receptor neurokinin-1 receptor (NK1R) and the superoxide-producing enzyme NADPH oxidase (NOX2) were necessary for SP-mediated chemotaxis in microglia. Furthermore, genetic ablation and pharmacological inhibition of NK1R or NOX2 attenuated SP-induced microglial migration. Finally, protein kinase Cδ (PKCδ) was recognized to couple SP/NK1R-mediated NOX2 activation. Altogether, we found that SP partly accounts for the increased density of microglia in the SN through chemotaxic recruitment via a novel NK1R-NOX2 axis-mediated pathway. © 2015 Authors; published by Portland Press Limited.

  5. Nadph oxidase regulates alveolar epithelial sodium channel activity and lung fluid balance in vivo via O2− signaling

    PubMed Central

    Goodson, Preston; Kumar, Amrita; Jain, Lucky; Kundu, Kousik; Murthy, Niren; Koval, Michael

    2012-01-01

    To define roles for reactive oxygen species (ROS) and epithelial sodium channel (ENaC) in maintaining lung fluid balance in vivo, we used two novel whole animal imaging approaches. Live X-ray fluoroscopy enabled quantification of air space fluid content of C57BL/6J mouse lungs challenged by intratracheal (IT) instillation of saline; results were confirmed by using conventional lung wet-to-dry weight ratios and Evans blue as measures of pulmonary edema. Visualization and quantification of ROS produced in lungs was performed in mice that had been administered a redox-sensitive dye, hydro-Cy7, by IT instillation. We found that inhibition of NADPH oxidase with a Rac-1 inhibitor, NSC23766, resulted in alveolar flooding, which correlated with a decrease in lung ROS production in vivo. Consistent with a role for Nox2 in alveolar fluid balance, Nox2−/− mice showed increased retention of air space fluid compared with wild-type controls. Interestingly, fluoroscopic analysis of C57BL/6J lungs IT instilled with LPS showed an acute stimulation of lung fluid clearance and ROS production in vivo that was abrogated by the ROS scavenger tetramethylpiperidine-N-oxyl (TEMPO). Acute application of LPS increased the activity of 20 pS nonselective ENaC channels in rat type 1 cells; the average number of channel and single-channel open probability (NPo) increased from 0.14 ± 0.04 to 0.62 ± 0.23. Application of TEMPO to the same cell-attached recording caused an immediate significant decrease in ENaC NPo to 0.04 ± 0.03. These data demonstrate that, in vivo, ROS has the capacity to stimulate lung fluid clearance by increasing ENaC activity. PMID:22160304

  6. Increased activation of NADPH oxidase 4 in the pulmonary vasculature in experimental diaphragmatic hernia.

    PubMed

    Gosemann, Jan-H; Friedmacher, Florian; Hunziker, Manuela; Alvarez, Luis; Corcionivoschi, Nicolae; Puri, Prem

    2013-01-01

    Persistent pulmonary hypertension remains a major cause of mortality and morbidity in congenital diaphragmatic hernia (CDH). NADPH oxidases (Nox) are the main source of superoxide production in vasculature. Nox4 is highly expressed in the smooth muscle and endothelial cells of the vascular wall and increased activity has been reported in the pulmonary vasculature of both experimental and human pulmonary hypertension. Peroxisome proliferator-activated receptor (PPARγ) is a key regulator of Nox4 expression. Targeted depletion of PPARγ results in pulmonary hypertension phenotype whereas activation of PPARγ attenuates pulmonary hypertension and reduces Nox4 production. The nitrofen-induced CDH model is an established model to study the pathogenesis of pulmonary hypertension in CDH. It has been previously reported that PPARγ-signaling is disrupted during late gestation and H(2)O(2) production is increased in nitrofen-induced CDH. We designed this study to investigate the hypothesis that Nox4 expression and activation is increased and vascular PPARγ is decreased in nitrofen-induced CDH. Pregnant rats were treated with either nitrofen or vehicle on gestational day 9 (D9). Fetuses were sacrificed on D21 and divided into control and CDH. RT-PCR, western blotting and confocal-immunofluorescence-double-staining were performed to determine pulmonary expression levels of PPARγ, Nox4 and Nox4-activation (p22(phox)). There was a marked increase in medial and adventitial thickness in pulmonary arteries of all sizes in CDH compared to controls. Pulmonary Nox4 levels were significantly increased whereas PPARγ levels were decreased in nitrofen-induced CDH compared to controls. Western blotting revealed increased pulmonary protein expression of the Nox4-activating subunit p22(phox) and decreased protein expression of PPARγ in CDH compared to controls. Confocal-microscopy confirmed markedly increased pulmonary expression of the Nox4 activating subunit p22(phox) accompanied by

  7. Anti-inflammatory activity of Chios mastic gum is associated with inhibition of TNF-alpha induced oxidative stress

    PubMed Central

    2011-01-01

    Background Gum of Chios mastic (Pistacia lentiscus var. chia) is a natural antimicrobial agent that has found extensive use in pharmaceutical products and as a nutritional supplement. The molecular mechanisms of its anti-inflammatory activity, however, are not clear. In this work, the potential role of antioxidant activity of Chios mastic gum has been evaluated. Methods Scavenging of superoxide radical was investigated by electron spin resonance and spin trapping technique using EMPO spin trap in xanthine oxidase system. Superoxide production in endothelial and smooth muscle cells stimulated with TNF-α or angiotensin II and treated with vehicle (DMSO) or mastic gum (0.1-10 μg/ml) was measured by DHE and HPLC. Cellular H2O2 was measured by Amplex Red. Inhibition of protein kinase C (PKC) with mastic gum was determined by the decrease of purified PKC activity, by inhibition of PKC activity in cellular homogenate and by attenuation of superoxide production in cells treated with PKC activator phorbol 12-myristate 13-acetate (PMA). Results Spin trapping study did not show significant scavenging of superoxide by mastic gum itself. However, mastic gum inhibited cellular production of superoxide and H2O2 in dose dependent manner in TNF-α treated rat aortic smooth muscle cells but did not affect unstimulated cells. TNF-α significantly increased the cellular superoxide production by NADPH oxidase, while mastic gum completely abolished this stimulation. Mastic gum inhibited the activity of purified PKC, decreased PKC activity in cell homogenate, and attenuated superoxide production in cells stimulated with PKC activator PMA and PKC-dependent angiotensin II in endothelial cells. Conclusion We suggest that mastic gum inhibits PKC which attenuates production of superoxide and H2O2 by NADPH oxidases. This antioxidant property may have direct implication to the anti-inflammatory activity of the Chios mastic gum. PMID:21645369

  8. NADPH oxidase 4 is involved in the triethylene glycol dimethacrylate-induced reactive oxygen species and apoptosis in human embryonic palatal mesenchymal and dental pulp cells.

    PubMed

    Yeh, Cheng-Chang; Chang, Jenny Zwei-Chieng; Yang, Wan-Hsien; Chang, Hao-Hueng; Lai, Eddie Hsiang-Hua; Kuo, Mark Yen-Ping

    2015-07-01

    Triethylene glycol dimethacrylate (TEGDMA) is a common component of resin-based dental composites and endodontic sealers. TEGDMA induces apoptosis in several types of cells. However, the mechanisms are not completely understood. The aim of this study was to investigate the mechanisms underlying TEGDMA-induced apoptosis in human embryonic palatal mesenchymal (HEPM) pre-osteoblasts and primary human dental pulp (HDP) cells. Cell viability was examined after TEGDMA treatment. Cell cycle progression was checked by flow cytometry. Apoptotic cells were evaluated using terminal deoxynucleotidyl transferase (TdT)-mediated dUTP nick end labeling assay and visualized by fluorescence microscopy. Western blot analyses were performed to determine expressions of apoptosis-related proteins. The production of reactive oxygen species (ROS) was detected using flow cytometry. NADPH oxidase 4 (NOX4) expression levels were investigated using real-time quantitative polymerase chain reaction and Western blot analyses. TEGDMA increased cytosol cytochrome c levels and activated caspase-9 in HEPM and HDP cells. TEGDMA decreased the expression of anti-apoptotic protein Bcl-XL. TEGDMA-induced apoptosis was inhibited by caspase-9-specific inhibitor, anti-oxidants, NOX inhibitor, NOX4 inhibitor, and NOX4 small interfering RNA (siRNA). TEGDMA increased ROS production and upregulated NOX4 mRNA and protein expression. TEGDMA-induced intracellular ROS production was inhibited by NOX inhibitor and NOX4 inhibitor. We demonstrate significant involvement of NOX4 in the TEGDMA-induced ROS. NOX4-derived ROS subsequently induces mitochondrial cytochrome c release leading to apoptosis through activation of the intrinsic apoptotic pathway. NOX4 may be a potential target for strategies to prevent or ameliorate the TEGDMA-induced toxicity in HEPM and HDP cells.

  9. Aspirin suppresses cardiac fibroblast proliferation and collagen formation through downregulation of angiotensin type 1 receptor transcription

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

    Wang, Xianwei, E-mail: XWang2@UAMS.edu; Lu, Jingjun; Khaidakov, Magomed

    Aspirin (acetyl salicylic acid, ASA) is a common drug used for its analgesic and antipyretic effects. Recent studies show that ASA not only blocks cyclooxygenase, but also inhibits NADPH oxidase and resultant reactive oxygen species (ROS) generation, a pathway that underlies pathogenesis of several ailments, including hypertension and tissue remodeling after injury. In these disease states, angiotensin II (Ang II) activates NADPH oxidase via its type 1 receptor (AT1R) and leads to fibroblast growth and collagen synthesis. In this study, we examined if ASA would inhibit NADPH oxidase activation, upregulation of AT1R transcription, and subsequent collagen generation in mouse cardiacmore » fibroblasts challenged with Ang II. Mouse heart fibroblasts were isolated and treated with Ang II with or without ASA. As expected, Ang II induced AT1R expression, and stimulated cardiac fibroblast growth and collagen synthesis. The AT1R blocker losartan attenuated these effects of Ang II. Similarly to losartan, ASA, and its SA moiety suppressed Ang II-mediated AT1R transcription and fibroblast proliferation as well as expression of collagens and MMPs. ASA also suppressed the expression of NADPH oxidase subunits (p22{sup phox}, p47{sup phox}, p67{sup phox}, NOX2 and NOX4) and ROS generation. ASA did not affect total NF-κB p65, but inhibited its phosphorylation and activation. These observations suggest that ASA inhibits Ang II-induced NADPH oxidase expression, NF-κB activation and AT1R transcription in cardiac fibroblasts, and fibroblast proliferation and collagen expression. The critical role of NADPH oxidase activity in stimulation of AT1R transcription became apparent in experiments where ASA also inhibited AT1R transcription in cardiac fibroblasts challenged with H{sub 2}O{sub 2}. Since SA had similar effect as ASA on AT1R expression, we suggest that ASA's effect is mediated by its SA moiety. -- Highlights: ► Aspirin in therapeutic concentrations decreases mouse cardiac

  10. Root respiratory burst oxidase homologue-dependent H2O2 production confers salt tolerance on a grafted cucumber by controlling Na+ exclusion and stomatal closure

    PubMed Central

    Niu, Mengliang; Huang, Yuan; Sun, Shitao; Sun, Jingyu; Cao, Haishun; Shabala, Sergey

    2018-01-01

    Abstract Plant salt tolerance can be improved by grafting onto salt-tolerant rootstocks. However, the underlying signaling mechanisms behind this phenomenon remain largely unknown. To address this issue, we used a range of physiological and molecular techniques to study responses of self-grafted and pumpkin-grafted cucumber plants exposed to 75 mM NaCl stress. Pumpkin grafting significantly increased the salt tolerance of cucumber plants, as revealed by higher plant dry weight, chlorophyll content and photochemical efficiency (Fv/Fm), and lower leaf Na+ content. Salinity stress resulted in a sharp increase in H2O2 production, reaching a peak 3 h after salt treatment in the pumpkin-grafted cucumber. This enhancement was accompanied by elevated relative expression of respiratory burst oxidase homologue (RBOH) genes RbohD and RbohF and a higher NADPH oxidase activity. However, this increase was much delayed in the self-grafted plants, and the difference between the two grafting combinations disappeared after 24 h. The decreased leaf Na+ content of pumpkin-grafted plants was achieved by higher Na+ exclusion in roots, which was driven by the Na+/H+ antiporter energized by the plasma membrane H+-ATPase, as evidenced by the higher plasma membrane H+-ATPase activity and higher transcript levels for PMA and SOS1. In addition, early stomatal closure was also observed in the pumpkin-grafted cucumber plants, reducing water loss and maintaining the plant’s hydration status. When pumpkin-grafted plants were pretreated with an NADPH oxidase inhibitor, diphenylene iodonium (DPI), the H2O2 level decreased significantly, to the level found in self-grafted plants, resulting in the loss of the salt tolerance. Inhibition of the NADPH oxidase-mediated H2O2 signaling in the root also abolished a rapid stomatal closure in the pumpkin-grafted plants. We concluded that the pumpkin-grafted cucumber plants increase their salt tolerance via a mechanism involving the root-sourced respiratory

  11. Serotonin Signaling Through the 5-HT1B Receptor and NADPH Oxidase 1 in Pulmonary Arterial Hypertension

    PubMed Central

    Hood, Katie Y.; Mair, Kirsty M.; Harvey, Adam P.; Montezano, Augusto C.; Touyz, Rhian M.

    2017-01-01

    Objective— Serotonin can induce human pulmonary artery smooth muscle cell (hPASMC) proliferation through reactive oxygen species (ROS), influencing the development of pulmonary arterial hypertension (PAH). We hypothesize that in PASMCs, serotonin induces oxidative stress through NADPH-oxidase–derived ROS generation and reduced Nrf-2 (nuclear factor [erythroid-derived 2]-like 2) antioxidant systems, promoting vascular injury. Approach and Results— HPASMCs from controls and PAH patients, and PASMCs from Nox1−/− mice, were stimulated with serotonin in the absence/presence of inhibitors of Src kinase, the 5-HT1B receptor, and NADPH oxidase 1 (Nox1). Markers of fibrosis were also determined. The pathophysiological significance of our findings was examined in vivo in serotonin transporter overexpressing female mice, a model of pulmonary hypertension. We confirmed thatserotonin increased superoxide and hydrogen peroxide production in these cells. For the first time, we show that serotonin increased oxidized protein tyrosine phosphatases and hyperoxidized peroxiredoxin and decreased Nrf-2 and catalase activity in hPASMCs. ROS generation was exaggerated and dependent on cellular Src-related kinase, 5-HT1B receptor, and the serotonin transporter in human pulmonary artery smooth muscle cells from PAH subjects. Proliferation and extracellular matrix remodeling were exaggerated in human pulmonary artery smooth muscle cells from PAH subjects and dependent on 5-HT1B receptor signaling and Nox1, confirmed in PASMCs from Nox1−/− mice. In serotonin transporter overexpressing mice, SB216641, a 5-HT1B receptor antagonist, prevented development of pulmonary hypertension in a ROS-dependent manner. Conclusions— Serotonin can induce cellular Src-related kinase–regulated Nox1-induced ROS and Nrf-2 dysregulation, contributing to increased post-translational oxidative modification of proteins and activation of redox-sensitive signaling pathways in hPASMCs, associated with

  12. Ciproxifan, a histamine H3 receptor antagonist, reversibly inhibits monoamine oxidase A and B

    PubMed Central

    Hagenow, S.; Stasiak, A.; Ramsay, R. R.; Stark, H.

    2017-01-01

    Ciproxifan is a well-investigated histamine H3 receptor (H3R) inverse agonist/antagonist, showing an exclusively high species-specific affinity at rodent compared to human H3R. It is well studied as reference compound for H3R in rodent models for neurological diseases connected with neurotransmitter dysregulation, e.g. attention deficit hyperactivity disorder or Alzheimer’s disease. In a screening for potential monoamine oxidase A and B inhibition ciproxifan showed efficacy on both enzyme isoforms. Further characterization of ciproxifan revealed IC50 values in a micromolar concentration range for human and rat monoamine oxidases with slight preference for monoamine oxidase B in both species. The inhibition by ciproxifan was reversible for both human isoforms. Regarding inhibitory potency of ciproxifan on rat brain MAO, these findings should be considered, when using high doses in rat models for neurological diseases. As the H3R and monoamine oxidases are all capable of affecting neurotransmitter modulation in brain, we consider dual targeting ligands as interesting approach for treatment of neurological disorders. Since ciproxifan shows only moderate activity at human targets, further investigations in animals are not of primary interest. On the other hand, it may serve as starting point for the development of dual targeting ligands. PMID:28084411

  13. Angiotensin II modulates mouse skeletal muscle resting conductance to chloride and potassium ions and calcium homeostasis via the AT1 receptor and NADPH oxidase

    PubMed Central

    Cozzoli, Anna; Liantonio, Antonella; Conte, Elena; Cannone, Maria; Massari, Ada Maria; Giustino, Arcangela; Scaramuzzi, Antonia; Pierno, Sabata; Mantuano, Paola; Capogrosso, Roberta Francesca; Camerino, Giulia Maria

    2014-01-01

    Angiotensin II (ANG II) plays a role in muscle wasting and remodeling; however, little evidence shows its direct effects on specific muscle functions. We presently investigated the acute in vitro effects of ANG II on resting ionic conductance and calcium homeostasis of mouse extensor digitorum longus (EDL) muscle fibers, based on previous findings that in vivo inhibition of ANG II counteracts the impairment of macroscopic ClC-1 chloride channel conductance (gCl) in the mdx mouse model of muscular dystrophy. By means of intracellular microelectrode recordings we found that ANG II reduced gCl in the nanomolar range and in a concentration-dependent manner (EC50 = 0.06 μM) meanwhile increasing potassium conductance (gK). Both effects were inhibited by the ANG II receptors type 1 (AT1)-receptor antagonist losartan and the protein kinase C inhibitor chelerythrine; no antagonism was observed with the AT2 antagonist PD123,319. The scavenger of reactive oxygen species (ROS) N-acetyl cysteine and the NADPH-oxidase (NOX) inhibitor apocynin also antagonized ANG II effects on resting ionic conductances; the ANG II-dependent gK increase was blocked by iberiotoxin, an inhibitor of calcium-activated potassium channels. ANG II also lowered the threshold for myofiber and muscle contraction. Both ANG II and the AT1 agonist L162,313 increased the intracellular calcium transients, measured by fura-2, with a two-step pattern. These latter effects were not observed in the presence of losartan and of the phospholipase C inhibitor U73122 and the in absence of extracellular calcium, disclosing a Gq-mediated calcium entry mechanism. The data show for the first time that the AT1-mediated ANG II pathway, also involving NOX and ROS, directly modulates ion channels and calcium homeostasis in adult myofibers. PMID:25080489

  14. Angiotensin II modulates mouse skeletal muscle resting conductance to chloride and potassium ions and calcium homeostasis via the AT1 receptor and NADPH oxidase.

    PubMed

    Cozzoli, Anna; Liantonio, Antonella; Conte, Elena; Cannone, Maria; Massari, Ada Maria; Giustino, Arcangela; Scaramuzzi, Antonia; Pierno, Sabata; Mantuano, Paola; Capogrosso, Roberta Francesca; Camerino, Giulia Maria; De Luca, Annamaria

    2014-10-01

    Angiotensin II (ANG II) plays a role in muscle wasting and remodeling; however, little evidence shows its direct effects on specific muscle functions. We presently investigated the acute in vitro effects of ANG II on resting ionic conductance and calcium homeostasis of mouse extensor digitorum longus (EDL) muscle fibers, based on previous findings that in vivo inhibition of ANG II counteracts the impairment of macroscopic ClC-1 chloride channel conductance (gCl) in the mdx mouse model of muscular dystrophy. By means of intracellular microelectrode recordings we found that ANG II reduced gCl in the nanomolar range and in a concentration-dependent manner (EC50 = 0.06 μM) meanwhile increasing potassium conductance (gK). Both effects were inhibited by the ANG II receptors type 1 (AT1)-receptor antagonist losartan and the protein kinase C inhibitor chelerythrine; no antagonism was observed with the AT2 antagonist PD123,319. The scavenger of reactive oxygen species (ROS) N-acetyl cysteine and the NADPH-oxidase (NOX) inhibitor apocynin also antagonized ANG II effects on resting ionic conductances; the ANG II-dependent gK increase was blocked by iberiotoxin, an inhibitor of calcium-activated potassium channels. ANG II also lowered the threshold for myofiber and muscle contraction. Both ANG II and the AT1 agonist L162,313 increased the intracellular calcium transients, measured by fura-2, with a two-step pattern. These latter effects were not observed in the presence of losartan and of the phospholipase C inhibitor U73122 and the in absence of extracellular calcium, disclosing a Gq-mediated calcium entry mechanism. The data show for the first time that the AT1-mediated ANG II pathway, also involving NOX and ROS, directly modulates ion channels and calcium homeostasis in adult myofibers. Copyright © 2014 the American Physiological Society.

  15. Involvement of NADPH oxidase isoforms in the production of O2- manipulated by ABA in the senescing leaves of early-senescence-leaf (esl) mutant rice (Oryza sativa).

    PubMed

    Li, Zhaowei; Wang, Fubiao; Zhao, Qian; Liu, Jianchao; Cheng, Fangmin

    2018-01-01

    In this study, the differences in reactive oxygen species (ROS) generation and abscisic acid (ABA) accumulation in senescing leaves were investigated by early-senescence-leaf (esl) mutant and its wild type, to clarify the relationship among ABA levels, ROS generation, and NADPH oxidase (Nox) in senescing leaves of rice (Oryza sativa). The temporal expression levels of OsNox isoforms in senescing leaves and their expression patterns in response to ABA treatment were determined through quantitative real-time reverse transcription PCR (qRT-PCR). Results showed that the flag leaf of the esl mutant generated more O2- concentrations and accumulated higher ABA levels than the wild-type cultivar did in the grain-filling stage. Exogenous ABA treatment induced O2- generation; however, it was depressed by diphenyleneiodonium chloride (DPI) pretreatment in the detached leaf segments. This finding suggested the involvement of NADPH oxidase in ABA-induced O2- generation. The esl mutant exhibited significantly higher expression of OsNox2, OsNox5, OsNox6, and OsNox7 in the initial of grain-filling stage, followed by sharply decrease. The transcriptional levels of OsNox1, OsNox3, and OsFR07 in the flag leaf of the esl mutant were significantly lower than those in the wild-type cultivar. The expression levels of OsNox2, OsNox5, OsNox6, and OsNox7 were significantly enhanced by exogenous ABA treatments. The enhanced expression levels of OsNox2 and OsNox6 were dependent on the duration of ABA treatment. The inducible expression levels of OsNox5 and OsNox7 were dependent on ABA concentrations. By contrast, exogenous ABA treatment severely repressed the transcripts of OsNox1, OsNox3, and OsFR07 in the detached leaf segments. Therefore, OsNox2, OsNox5, OsNox6, and OsNox7 were probably involved in the ABA-induced O2- generation in the initial stage of leaf senescence. Subsequently, other oxidases activated in deteriorating cells were associated with ROS generation and accumulation in the

  16. Dithiocarbamates are teratogenic to developing zebrafish through inhibition of lysyl oxidase activity

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

    Boxtel, Antonius L. van, E-mail: thijs.van.boxtel@ivm.vu.n; Kamstra, Jorke H.; Fluitsma, Donna M.

    2010-04-15

    Dithiocarbamates (DTCs) are a class of compounds that are extensively used in agriculture as pesticides. As such, humans and wildlife are undoubtedly exposed to these chemicals. Although DTCs are thought to be relatively safe due to their short half lives, it is well established that they are teratogenic to vertebrates, especially to fish. In zebrafish, these teratogenic effects are characterized by distorted notochord development and shortened anterior to posterior axis. DTCs are known copper (Cu) chelators but this does not fully explain the observed teratogenic effects. We show here that DTCs cause malformations in zebrafish that highly resemble teratogenic effectsmore » observed by direct inhibition of a group of cuproenzymes termed lysyl oxidases (LOX). Additionally, we demonstrate that partial knockdown of three LOX genes, lox, loxl1 and loxl5b, sensitizes the developing embryo to DTC exposure. Finally, we show that DTCs directly inhibit zebrafish LOX activity in an ex vivo amine oxidase assay. Taken together, these results provide the first evidence that DTC induced teratogenic effects are, at least in part, caused by direct inhibition of LOX activity.« less

  17. Resveratrol Protects Dopamine Neurons Against Lipopolysaccharide-Induced Neurotoxicity through Its Anti-Inflammatory Actions

    PubMed Central

    Zhang, Feng; Shi, Jing-Shan; Zhou, Hui; Wilson, Belinda; Hong, Jau-Shyong

    2010-01-01

    Parkinson's disease (PD) is the second most common neurodegenerative disease characterized by a progressive loss of dopamine (DA) neurons in the substantia nigra. Accumulating evidence indicates that inhibition of microglia-mediated neuroinflammation may become a reliable protective strategy for PD. Resveratrol, a nonflavonoid polyphenol naturally found in red wine and grapes, has been known to possess antioxidant, anticancer, and anti-inflammatory properties. Although recent studies have shown that resveratrol provided neuroprotective effects against ischemia, seizure, and neurodegenerative disorders, the mechanisms underlying its beneficial effects on dopaminergic neurodegeneration are poorly defined. In this study, rat primary midbrain neuron-glia cultures were used to elucidate the molecular mechanisms underlying resveratrol-mediated neuroprotection. The results clearly demonstrated that resveratrol protected DA neurons against lipopolysaccharide (LPS)-induced neurotoxicity in concentration- and time-dependent manners through the inhibition of microglial activation and the subsequent reduction of proinflammatory factor release. Mechanistically, resveratrol-mediated neuroprotection was attributed to the inhibition of NADPH oxidase. This conclusion is supported by the following observations. First, resveratrol reduced NADPH oxidase-mediated generation of reactive oxygen species. Second, LPS-induced translocation of NADPH oxidase cytosolic subunit p47 to the cell membrane was significantly attenuated by resveratrol. Third and most importantly, resveratrol failed to exhibit neuroprotection in cultures from NADPH oxidase-deficient mice. Furthermore, this neuroprotection was also related to an attenuation of the activation of mitogen-activated protein kinases and nuclear factor-κB signaling pathways in microglia. These findings suggest that resveratrol exerts neuroprotection against LPS-induced dopaminergic neurodegeneration, and NADPH oxidase may be a major player

  18. NADPH oxidase 2 (NOX2) enzyme activation in patients with chronic inflammatory demyelinating polyneuropathy.

    PubMed

    Marrali, G; Salamone, P; Casale, F; Fuda, G; Cugnasco, P; Caorsi, C; Amoroso, A; Calvo, A; Lopiano, L; Cocito, D; Chiò, A

    2016-05-01

    Chronic inflammatory demyelinating polyneuropathy (CIDP) is an acquired immunomediated condition affecting the peripheral nervous system where probably macrophages are the primary effector cells for demyelination. Reactive oxygen species (ROS), catalyzed by the NOX family of nicotinamide adenine dinucleotide phosphate (NADPH) oxidase enzymes, can induce peroxidation and are potentially injurious to myelin. Our aim was to assess the activity of NOX2, an isoform of NOX, in a series of CIDP patients and to analyze the effect of intravenous immunoglobulin (IVIg) on NOX2. Thirty CIDP patients treated with IVIg and 30 control subjects were enrolled. To evaluate NOX2 activity, neutrophil and monocyte oxidative burst was measured directly in fresh whole blood using the Phagoburst™ assay, a fluorescence-activated cell sorting method. The mean fluorescence intensity, emitted in response to different stimuli, leads to the production of ROS and corresponds to the percentage of oxidizing cells and their enzymatic activity. Mean fluorescence intensity values for granulocyte and monocyte burst in patients (mean 633.3, SD 191; mean 111.8, SD 28.5) were different from those measured in healthy controls (granulocytes, mean 436.6, SD 137.0, P = 0.0003; monocytes, mean 78.2, SD 17.3, P = 0.000001). Moreover, IVIg administration increased both granulocyte (P = 0.005) and monocyte (P = 0.0009) burst. Our findings demonstrate that oxidative burst is significantly increased in CIDP patients and that treatment with IVIg enhances oxidative values, thus representing a possible IVIg therapeutic effect linked to a regulatory effect of ROS. Based on this, the development of treatments targeting the specific activation of NOX may be beneficial in autoimmune disorders. © 2016 EAN.

  19. Characterization of N-glycosylation sites on the extracellular domain of NOX1/NADPH oxidase.

    PubMed

    Matsumoto, Misaki; Katsuyama, Masato; Iwata, Kazumi; Ibi, Masakazu; Zhang, Jia; Zhu, Kai; Nauseef, William M; Yabe-Nishimura, Chihiro

    2014-03-01

    Extensive evidence demonstrates the pathophysiological importance of NOX1, the catalytic subunit of superoxide-generating enzyme NADPH oxidase, as a source of reactive oxygen species in nonphagocytic cells. However, the biochemical properties of NOX1 have not been extensively characterized due to a lack of specific immunological tools. We used a newly raised NOX1 polyclonal antibody to investigate posttranslational modifications of NOX1 overexpressed in cultured cells and in the colon, where endogenous NOX1 is highly expressed. Immunoblots of lysates from cells expressing NOX1 revealed a doublet of 56 and 60kDa accompanied by a broad band of 60-90kDa. Based on differential sensitivity to glycosidases, the doublet was identified as two high-mannose-type glycoforms of NOX1, whereas the broad band represented NOX1 with complex-type N-linked oligosaccharides. Deglycosylated NOX1 migrated at ~53kDa and N-glycosylation was demonstrated in NOX1 derived from both rat and human. Site-directed mutagenesis identified N-glycosylation sites at Asn(161) and Asn(241) on the extracellular loop of mouse NOX1. Elimination of N-glycosylation on NOX1 did not affect its electron transferase activity, protein stability, targeting to the cell surface, or localization in F-actin-positive membrane protrusions. Taken together, these data identify the two specific sites of N-linked glycosylation of murine NOX1 and demonstrate that they are not required for normal enzyme activity, protein stability, and membrane trafficking. As is true for NOX2, the contribution of glycosylation in NOX1 to its biologic function(s) merits further study. Copyright © 2013 Elsevier Inc. All rights reserved.

  20. Identification of NoxD/Pro41 as the homologue of the p22phox NADPH oxidase subunit in fungi.

    PubMed

    Lacaze, Isabelle; Lalucque, Hervé; Siegmund, Ulrike; Silar, Philippe; Brun, Sylvain

    2015-03-01

    NADPH oxidases (Nox) are membrane complexes that produce O2(-). Researches in mammals, plants and fungi highlight the involvement of Nox-generated ROS in cell proliferation, differentiation and defense. In mammals, the core enzyme gp91(phox)/Nox2 is associated with p22(phox) forming the flavocytochrome b558 ready for activation by a cytosolic complex. Intriguingly, no homologue of the p22(phox) gene has been found in fungal genomes, questioning how the flavoenzyme forms. Using whole genome sequencing combined with phylogenetic analysis and structural studies, we identify the fungal p22(phox) homologue as being mutated in the Podospora anserina mutant IDC(509). Functional studies show that the fungal p22(phox), PaNoxD, acts along PaNox1, but not PaNox2, a second fungal gp91(phox) homologue. Finally, cytological analysis of functional tagged versions of PaNox1, PaNoxD and PaNoxR shows clear co-localization of PaNoxD and PaNox1 and unravel a dynamic assembly of the complex in the endoplasmic reticulum and in the vacuolar system. © 2014 John Wiley & Sons Ltd.

  1. mTORC2 Signaling Regulates Nox4-Induced Podocyte Depletion in Diabetes

    PubMed Central

    Eid, Stéphanie; Boutary, Suzan; Braych, Kawthar; Sabra, Ramzi; Massaad, Charbel; Hamdy, Ahmed; Rashid, Awad; Moodad, Sarah; Block, Karen; Gorin, Yves; Abboud, Hanna E.

    2016-01-01

    Abstract Aim: Podocyte apoptosis is a critical mechanism for excessive loss of urinary albumin that eventuates in kidney fibrosis. Oxidative stress plays a critical role in hyperglycemia-induced glomerular injury. We explored the hypothesis that mammalian target of rapamycin complex 2 (mTORC2) mediates podocyte injury in diabetes. Results: High glucose (HG)-induced podocyte injury reflected by alterations in the slit diaphragm protein podocin and podocyte depletion/apoptosis. This was paralleled by activation of the Rictor/mTORC2/Akt pathway. HG also increased the levels of Nox4 and NADPH oxidase activity. Inhibition of mTORC2 using small interfering RNA (siRNA)-targeting Rictor in vitro decreased HG-induced Nox1 and Nox4, NADPH oxidase activity, restored podocin levels, and reduced podocyte depletion/apoptosis. Inhibition of mTORC2 had no effect on mammalian target of rapamycin complex 1 (mTORC1) activation, described by our group to be increased in diabetes, suggesting that the mTORC2 activation by HG could mediate podocyte injury independently of mTORC1. In isolated glomeruli of OVE26 mice, there was a similar activation of the Rictor/mTORC2/Akt signaling pathway with increase in Nox4 and NADPH oxidase activity. Inhibition of mTORC2 using antisense oligonucleotides targeting Rictor restored podocin levels, reduced podocyte depletion/apoptosis, and attenuated glomerular injury and albuminuria. Innovation: Our data provide evidence for a novel function of mTORC2 in NADPH oxidase-derived reactive oxygen species generation and podocyte apoptosis that contributes to urinary albumin excretion in type 1 diabetes. Conclusion: mTORC2 and/or NADPH oxidase inhibition may represent a therapeutic modality for diabetic kidney disease. Antioxid. Redox Signal. 25, 703–719. PMID:27393154

  2. The inhibition of amine oxidase and the central stimulating action of the stereoisomeric amphetamines and 1-phenylethylamines

    PubMed Central

    Grana, E.; Lilla, L.

    1959-01-01

    The stereoisomers of amphetamine and 1-phenylethylamine have been studied in the rat both as central stimulants and as inhibitors of amine oxidase from brain, liver, and kidney. There was no correlation between these two effects; thus it is unlikely that the central stimulating action of amphetamine is due to inhibition of amine oxidase. PMID:13828860

  3. WRKY Transcription Factors Phosphorylated by MAPK Regulate a Plant Immune NADPH Oxidase in Nicotiana benthamiana[OPEN

    PubMed Central

    Adachi, Hiroaki; Nakano, Takaaki; Miyagawa, Noriko; Ishihama, Nobuaki; Yoshioka, Miki; Katou, Yuri; Yaeno, Takashi

    2015-01-01

    Pathogen attack sequentially confers pattern-triggered immunity (PTI) and effector-triggered immunity (ETI) after sensing of pathogen patterns and effectors by plant immune receptors, respectively. Reactive oxygen species (ROS) play pivotal roles in PTI and ETI as signaling molecules. Nicotiana benthamiana RBOHB, an NADPH oxidase, is responsible for both the transient PTI ROS burst and the robust ETI ROS burst. Here, we show that RBOHB transactivation mediated by MAPK contributes to R3a/AVR3a-triggered ETI (AVR3a-ETI) ROS burst. RBOHB is markedly induced during the ETI and INF1-triggered PTI (INF1-PTI), but not flg22-tiggered PTI (flg22-PTI). We found that the RBOHB promoter contains a functional W-box in the R3a/AVR3a and INF1 signal-responsive cis-element. Ectopic expression of four phospho-mimicking mutants of WRKY transcription factors, which are MAPK substrates, induced RBOHB, and yeast one-hybrid analysis indicated that these mutants bind to the cis-element. Chromatin immunoprecipitation assays indicated direct binding of the WRKY to the cis-element in plants. Silencing of multiple WRKY genes compromised the upregulation of RBOHB, resulting in impairment of AVR3a-ETI and INF1-PTI ROS bursts, but not the flg22-PTI ROS burst. These results suggest that the MAPK-WRKY pathway is required for AVR3a-ETI and INF1-PTI ROS bursts by activation of RBOHB. PMID:26373453

  4. NADPH oxidase-4 mediates protection against chronic load-induced stress in mouse hearts by enhancing angiogenesis

    PubMed Central

    Zhang, Min; Brewer, Alison C.; Schröder, Katrin; Santos, Celio X. C.; Grieve, David J.; Wang, Minshu; Anilkumar, Narayana; Yu, Bin; Dong, Xuebin; Walker, Simon J.; Brandes, Ralf P.; Shah, Ajay M.

    2010-01-01

    Cardiac failure occurs when the heart fails to adapt to chronic stresses. Reactive oxygen species (ROS)-dependent signaling is implicated in cardiac stress responses, but the role of different ROS sources remains unclear. Here we report that NADPH oxidase-4 (Nox4) facilitates cardiac adaptation to chronic stress. Unlike other Nox proteins, Nox4 activity is regulated mainly by its expression level, which increases in cardiomyocytes under stresses such as pressure overload or hypoxia. To investigate the functional role of Nox4 during the cardiac response to stress, we generated mice with a genetic deletion of Nox4 or a cardiomyocyte-targeted overexpression of Nox4. Basal cardiac function was normal in both models, but Nox4-null animals developed exaggerated contractile dysfunction, hypertrophy, and cardiac dilatation during exposure to chronic overload whereas Nox4-transgenic mice were protected. Investigation of mechanisms underlying this protective effect revealed a significant Nox4-dependent preservation of myocardial capillary density after pressure overload. Nox4 enhanced stress-induced activation of cardiomyocyte hypoxia inducible factor 1 and the release of vascular endothelial growth factor, resulting in increased paracrine angiogenic activity. These data indicate that cardiomyocyte Nox4 is a unique inducible regulator of myocardial angiogenesis, a key determinant of cardiac adaptation to overload stress. Our results also have wider relevance to the use of nonspecific antioxidant approaches in cardiac disease and may provide an explanation for the failure of such strategies in many settings. PMID:20921387

  5. Studying neuroprotective effect of Atorvastatin as a small molecule drug on high glucose-induced neurotoxicity in undifferentiated PC12 cells: role of NADPH oxidase.

    PubMed

    Rayegan, Samira; Dehpour, Ahmad Reza; Sharifi, Ali Mohammad

    2017-02-01

    Overproduction of reactive oxygen species (ROS) by NADPH oxidase (NOX) activation has been considered the essential mechanism induced by hyperglycemia in various tissues. However, there is no comprehensive study on the role of NOXs in high glucose (HG)-induced toxic effect in neural tissues. Recently, a therapeutic strategy in oxidative related pathologies has been introduced by blocking the undesirable actions of NOX enzymes by small molecules. The protective roles of Statins in ameliorating oxidative stress by NOX inhibition have been shown in some tissues except neural. We hypothesized then, that different NOXs may have role in HG-induced neural cell injury. Furthermore, we postulate that Atorvastatin as a small molecule may modulate this NOXs activity to protect neural cells. Undifferentiated PC12 cells were treated with HG (140 mM/24 h) in the presence and absence of Atorvastatin (1 μM/96 h). The cell viability was measured by MTT assay and the gene and protein expressions profile of NOX (1-4) were determined by RT-PCR and western blotting, respectively. Levels of ROS and malondialdehyde (MDA) were also evaluated. Gene and protein expression levels of NOX (1-4) and consequently ROS and MDA levels were elevated in HG-treated PC12 cells. Atorvastatin could significantly decrease HG-induced NOXs, ROS and MDA elevation and improve impaired cell viability. It can be concluded that HG could elevate NOXs activity, ROS and MDA levels in neural tissues and Atorvastatin as a small molecule NOX inhibitor drug may prevent and delay diabetic complications, particularly neuropathy.

  6. Reduction of NADPH-Oxidase Activity Ameliorates the Cardiovascular Phenotype in a Mouse Model of Williams-Beuren Syndrome

    PubMed Central

    Campuzano, Victoria; Segura-Puimedon, Maria; Terrado, Verena; Sánchez-Rodríguez, Carolina; Coustets, Mathilde; Menacho-Márquez, Mauricio; Nevado, Julián; Bustelo, Xosé R.; Francke, Uta; Pérez-Jurado, Luis A.

    2012-01-01

    A hallmark feature of Williams-Beuren Syndrome (WBS) is a generalized arteriopathy due to elastin deficiency, presenting as stenoses of medium and large arteries and leading to hypertension and other cardiovascular complications. Deletion of a functional NCF1 gene copy has been shown to protect a proportion of WBS patients against hypertension, likely through reduced NADPH-oxidase (NOX)–mediated oxidative stress. DD mice, carrying a 0.67 Mb heterozygous deletion including the Eln gene, presented with a generalized arteriopathy, hypertension, and cardiac hypertrophy, associated with elevated angiotensin II (angII), oxidative stress parameters, and Ncf1 expression. Genetic (by crossing with Ncf1 mutant) and/or pharmacological (with ang II type 1 receptor blocker, losartan, or NOX inhibitor apocynin) reduction of NOX activity controlled hormonal and biochemical parameters in DD mice, resulting in normalized blood pressure and improved cardiovascular histology. We provide strong evidence for implication of the redox system in the pathophysiology of the cardiovascular disease in a mouse model of WBS. The phenotype of these mice can be ameliorated by either genetic or pharmacological intervention reducing NOX activity, likely through reduced angII–mediated oxidative stress. Therefore, anti-NOX therapy merits evaluation to prevent the potentially serious cardiovascular complications of WBS, as well as in other cardiovascular disorders mediated by similar pathogenic mechanism. PMID:22319452

  7. The amine oxidase inhibitor phenelzine limits lipogenesis in adipocytes without inhibiting insulin action on glucose uptake.

    PubMed

    Carpéné, Christian; Grès, Sandra; Rascalou, Simon

    2013-06-01

    The antidepressant phenelzine is a monoamine oxidase inhibitor known to inhibit various other enzymes, among them semicarbazide-sensitive amine oxidase (currently named primary amine oxidase: SSAO/PrAO), absent from neurones but abundant in adipocytes. It has been reported that phenelzine inhibits adipocyte differentiation of cultured preadipocytes. To further explore the involved mechanisms, our aim was to study in vitro the acute effects of phenelzine on de novo lipogenesis in mature fat cells. Therefore, glucose uptake and incorporation into lipid were measured in mouse adipocytes in response to phenelzine, other hydrazine-based SSAO/PrAO-inhibitors, and reference agents. None of the inhibitors was able to impair the sevenfold activation of 2-deoxyglucose uptake induced by insulin. Phenelzine did not hamper the effect of lower doses of insulin. However, insulin-stimulated glucose incorporation into lipids was dose-dependently inhibited by phenelzine and pentamidine, but not by semicarbazide or BTT2052. In contrast, all these SSAO/PrAO inhibitors abolished the transport and lipogenesis stimulation induced by benzylamine. These data indicate that phenelzine does not inhibit glucose transport, the first step of lipogenesis, but inhibits at 100 μM the intracellular triacylglycerol assembly, consistently with its long-term anti-adipogenic effect and such rapid action was not found with all the hydrazine derivatives tested. Therefore, the alterations of body weight control consecutive to the use of this antidepressant drug might be not only related to central effects on food intake/energy expenditure, but could also depend on its direct action in adipocytes. Nonetheless, phenelzine antilipogenic action is not merely dependent on SSAO/PrAO inhibition.

  8. Inhibition effects of Vernonia cinerea active compounds against cytochrome P450 2A6 and human monoamine oxidases, possible targets for reduction of tobacco dependence.

    PubMed

    Prasopthum, Aruna; Pouyfung, Phisit; Sarapusit, Songklod; Srisook, Ekaruth; Rongnoparut, Pornpimol

    2015-04-01

    The human cytochrome P450 2A6 (CYP2A6) and monoamine oxidases (MAO-A and MAO-B), catalyzing nicotine and dopamine metabolisms, respectively, are two therapeutic targets of nicotine dependence. Vernonia cinerea, a medicinal plant commonly used for treatment of diseases such as asthma and bronchitis, has been shown reducing tobacco dependence effect among tobacco users. In the present study, we found eight active compounds isolated from V. cinerea that comprise inhibitory activity toward CYP2A6 and MAO-A and MAO-B enzymes using activity-guided assays, with coumarin as substrate of CYP2A6 and kynuramine of MAOs. These compounds were three flavones (apigenin, chrysoeriol, luteolin), one flavonol (quercetin), and four hirsutinolide-type sesquiterpene lactones (8α-(2-methylacryloyloxy)-hirsutinolide-13-O-acetate, 8α-(4-hydroxymethacryloyloxy)-hirsutinolide-13-O-acetate, 8α-tigloyloxyhirsutinolide-13-O-acetate, and 8α-(4-hydroxytigloyloxy)-hirsutinolide-13-O-acetate). Modes and kinetics of inhibition against the three enzymes were determined. Flavonoids possessed strong inhibitory effect on CYP2A6 in reversible mode, while inhibition by hirsutinolides was mechanism-based (NADPH-, concentration-, and time-dependence) and irreversible. Inhibition by hirsutinolides could not be reversed by dialysis and by addition of trapping agents or potassium ferricyanide. Flavonoids inhibited MAOs with variable degrees and were more prominent in inhibition toward MAO-A than hirsutinolides, while two of hirsutinolides inhibited MAO-B approximately comparable to two flavonoids. These results could have implications in combination of drug therapy for smoking cessation. Copyright © 2014 The Japanese Society for the Study of Xenobiotics. Published by Elsevier Ltd. All rights reserved.

  9. Inhibition of chrysin on xanthine oxidase activity and its inhibition mechanism.

    PubMed

    Lin, Suyun; Zhang, Guowen; Liao, Yijing; Pan, Junhui

    2015-11-01

    Chrysin, a bioactive flavonoid, was investigated for its potential to inhibit the activity of xanthine oxidase (XO), a key enzyme catalyzing xanthine to uric acid and finally causing gout. The kinetic analysis showed that chrysin possessed a strong inhibition on XO ability in a reversible competitive manner with IC50 value of (1.26±0.04)×10(-6)molL(-1). The results of fluorescence titrations indicated that chrysin bound to XO with high affinity, and the interaction was predominately driven by hydrogen bonds and van der Waals forces. Analysis of circular dichroism demonstrated that chrysin induced the conformational change of XO with increases in α-helix and β-sheet and reductions in β-turn and random coil structures. Molecular simulation revealed that chrysin interacted with the amino acid residues Leu648, Phe649, Glu802, Leu873, Ser876, Glu879, Arg880, Phe1009, Thr1010, Val1011 and Phe1013 located within the active cavity of XO. The mechanism of chrysin on XO activity may be the insertion of chrysin into the active site occupying the catalytic center of XO to avoid the entrance of xanthine and causing conformational changes in XO. Furthermore, the interaction assays indicated that chrysin and its structural analog apigenin exhibited an additive effect on inhibition of XO. Copyright © 2015 Elsevier B.V. All rights reserved.

  10. NAD(P)H oxidase p22(phox) polymorphism and cardiovascular function in amateur runners.

    PubMed

    Gallina, S; Di Francescomarino, S; Di Mauro, M; Izzicupo, P; D'Angelo, E; D'Amico, M A; Pennelli, A; Amicarelli, F; Di Baldassarre, A

    2012-09-01

    NAD(P)H system represents the major source of superoxide production at cardiovascular (CV) level. It has several genetic variants: in particular, the C242T polymorphism of its p22(phox) subunit is associated with a different oxidase activity, being the T allele related to a lower superoxide production. Although several authors investigated the protective effect of T allele in CV diseases, only few data are available on its functional role in physiological conditions. The aim of our study was to investigate the relationship between the p22(phox) C242T polymorphism and CV function in amateur runners. Seventy-three male amateur runners were screened for CYBA polymorphism. CV analysis was performed by echocardiographic-Doppler examination and by PulsePen tonometer assessment. The genetic subgroups (CC and CT/TT) did not differ for VM O(2max) and cardiac dimension. Nevertheless, T carriers (n = 40) were characterized by a more efficient myocardial contraction and left ventricular (LV) filling, as evidenced by significant higher values of the midwall fractional shortening, systolic excursion of the tricuspid annular plane and of early/late diastolic wave velocities ratio and by a lower E wave deceleration time. Pulse wave velocity and augmentation index, parameters related to the arterial stiffness, were higher in CC subjects compared with CT/TT also when the analysis was adjusted for weight and diastolic pressure. In amateur runners, CYBA variants may influence both systolic and diastolic function and arterial stiffness. We suppose that the lower oxidative activity that characterizes 242T subjects may positively influence the excitation-contraction and arterial-ventricular coupling mechanisms, thus leading to a more efficient CV function. © 2012 The Authors Acta Physiologica © 2012 Scandinavian Physiological Society.

  11. Xanthine oxidase inhibiting effects of noni (Morinda citrifolia) fruit juice.

    PubMed

    Palu, Afa; Deng, Shixin; West, Brett; Jensen, Jarakae

    2009-12-01

    Morinda citrifolia L. (noni), family Rubiaceae, has been used in Polynesia for over 2000 years for its reputed health benefits, one of which is its therapeutic effects on gout (langa e hokotanga hui). However, its healing mechanism has not been elucidated. This study showed that in an in vitro bioassay that Tahitian Noni Juice (TNJ) inhibited xanthine oxidase (XO) concentration dependently. Concentrations of 1, 5 and 10 mg/mL of TNJ inhibited XO by 11%, 113% and 148%, respectively, with an IC50 of 3.8 mg compared with an IC50 of 2.4 microm for allopurinol. Noni fruit juice concentrate (NFJC) also inhibited XO concentration dependently. Concentrations of 1 and 5 mg/mL NFJC inhibited XO in vitro by 184% and 159%, respectively. A 0.1 mg/mL methanol extract (NFJME) from the fractionation of noni fruit puree inhibited XO by 64%. It was elucidated that the noni fruit juice inhibitory effect on XO enzymes is the mechanism by which noni ameliorates gout and gout-like diseases. Further, the results also support the traditional usage of noni in the treatment of gout. Copyright (c) 2009 John Wiley & Sons, Ltd.

  12. Pleiotrophin-induced endothelial cell migration is regulated by xanthine oxidase-mediated generation of reactive oxygen species.

    PubMed

    Tsirmoula, Sotiria; Lamprou, Margarita; Hatziapostolou, Maria; Kieffer, Nelly; Papadimitriou, Evangelia

    2015-03-01

    Pleiotrophin (PTN) is a heparin-binding growth factor that induces cell migration through binding to its receptor protein tyrosine phosphatase beta/zeta (RPTPβ/ζ) and integrin alpha v beta 3 (ανβ3). In the present work, we studied the effect of PTN on the generation of reactive oxygen species (ROS) in human endothelial cells and the involvement of ROS in PTN-induced cell migration. Exogenous PTN significantly increased ROS levels in a concentration and time-dependent manner in both human endothelial and prostate cancer cells, while knockdown of endogenous PTN expression in prostate cancer cells significantly down-regulated ROS production. Suppression of RPTPβ/ζ through genetic and pharmacological approaches, or inhibition of c-src kinase activity abolished PTN-induced ROS generation. A synthetic peptide that blocks PTN-ανβ3 interaction abolished PTN-induced ROS generation, suggesting that ανβ3 is also involved. The latter was confirmed in CHO cells that do not express β3 or over-express wild-type β3 or mutant β3Y773F/Y785F. PTN increased ROS generation in cells expressing wild-type β3 but not in cells not expressing or expressing mutant β3. Phosphoinositide 3-kinase (PI3K) or Erk1/2 inhibition suppressed PTN-induced ROS production, suggesting that ROS production lays down-stream of PI3K or Erk1/2 activation by PTN. Finally, ROS scavenging and xanthine oxidase inhibition completely abolished both PTN-induced ROS generation and cell migration, while NADPH oxidase inhibition had no effect. Collectively, these data suggest that xanthine oxidase-mediated ROS production is required for PTN-induced cell migration through the cell membrane functional complex of ανβ3 and RPTPβ/ζ and activation of c-src, PI3K and ERK1/2 kinases. Copyright © 2015 Elsevier Inc. All rights reserved.

  13. Calcineurin Aβ regulates NADPH oxidase (Nox) expression and activity via nuclear factor of activated T cells (NFAT) in response to high glucose.

    PubMed

    Williams, Clintoria R; Gooch, Jennifer L

    2014-02-21

    Hypertrophy is an adaptive response that enables organs to appropriately meet increased functional demands. Previously, we reported that calcineurin (Cn) is required for glomerular and whole kidney hypertrophy in diabetic rodents (Gooch, J. L., Barnes, J. L., Garcia, S., and Abboud, H. E. (2003). Calcineurin is activated in diabetes and is required for glomerular hypertrophy and ECM accumulation. Am. J. Physiol. Renal Physiol. 284, F144-F154; Reddy, R. N., Knotts, T. L., Roberts, B. R., Molkentin, J. D., Price, S. R., and Gooch, J. L. (2011). Calcineurin Aβ is required for hypertrophy but not matrix expansion in the diabetic kidney. J. Cell Mol. Med. 15, 414-422). Because studies have also implicated the reactive oxygen species-generating enzymes NADPH oxidases (Nox) in diabetic kidney responses, we tested the hypothesis that Nox and Cn cooperate in a common signaling pathway. First, we examined the role of the two main isoforms of Cn in hypertrophic signaling. Using primary kidney cells lacking a catalytic subunit of Cn (CnAα(-/-) or CnAβ(-/-)), we found that high glucose selectively activates CnAβ, whereas CnAα is constitutively active. Furthermore, CnAβ but not CnAα mediates hypertrophy. Next, we found that chronic reactive oxygen species generation in response to high glucose is attenuated in CnAβ(-/-) cells, suggesting that Cn is upstream of Nox. Consistent with this, loss of CnAβ reduces basal expression and blocks high glucose induction of Nox2 and Nox4. Inhibition of nuclear factor of activated T cells (NFAT), a CnAβ-regulated transcription factor, decreases Nox2 and Nox4 expression, whereas NFAT overexpression increases Nox2 and Nox4, indicating that the CnAβ/NFAT pathway modulates Nox. These data reveal that the CnAβ/NFAT pathway regulates Nox and plays an important role in high glucose-mediated hypertrophic responses in the kidney.

  14. Involvement of NADPH oxidase isoforms in the production of O2− manipulated by ABA in the senescing leaves of early-senescence-leaf (esl) mutant rice (Oryza sativa)

    PubMed Central

    Wang, Fubiao; Zhao, Qian; Liu, Jianchao; Cheng, Fangmin

    2018-01-01

    In this study, the differences in reactive oxygen species (ROS) generation and abscisic acid (ABA) accumulation in senescing leaves were investigated by early-senescence-leaf (esl) mutant and its wild type, to clarify the relationship among ABA levels, ROS generation, and NADPH oxidase (Nox) in senescing leaves of rice (Oryza sativa). The temporal expression levels of OsNox isoforms in senescing leaves and their expression patterns in response to ABA treatment were determined through quantitative real-time reverse transcription PCR (qRT-PCR). Results showed that the flag leaf of the esl mutant generated more O2- concentrations and accumulated higher ABA levels than the wild-type cultivar did in the grain-filling stage. Exogenous ABA treatment induced O2- generation; however, it was depressed by diphenyleneiodonium chloride (DPI) pretreatment in the detached leaf segments. This finding suggested the involvement of NADPH oxidase in ABA-induced O2- generation. The esl mutant exhibited significantly higher expression of OsNox2, OsNox5, OsNox6, and OsNox7 in the initial of grain-filling stage, followed by sharply decrease. The transcriptional levels of OsNox1, OsNox3, and OsFR07 in the flag leaf of the esl mutant were significantly lower than those in the wild-type cultivar. The expression levels of OsNox2, OsNox5, OsNox6, and OsNox7 were significantly enhanced by exogenous ABA treatments. The enhanced expression levels of OsNox2 and OsNox6 were dependent on the duration of ABA treatment. The inducible expression levels of OsNox5 and OsNox7 were dependent on ABA concentrations. By contrast, exogenous ABA treatment severely repressed the transcripts of OsNox1, OsNox3, and OsFR07 in the detached leaf segments. Therefore, OsNox2, OsNox5, OsNox6, and OsNox7 were probably involved in the ABA-induced O2- generation in the initial stage of leaf senescence. Subsequently, other oxidases activated in deteriorating cells were associated with ROS generation and accumulation in the

  15. NADPH Phagocyte Oxidase Knockout Mice Control Trypanosoma cruzi Proliferation, but Develop Circulatory Collapse and Succumb to Infection

    PubMed Central

    Macedo, Juan P.; Utsch, Lara; Tafuri, Wagner L.; Campagnole-Santos, Maria José; Alves, Rosana O.; Alves-Filho, José C. F.; Romanha, Alvaro J.; Cunha, Fernando Queiroz; Teixeira, Mauro M.; Radi, Rafael; Vieira, Leda Q.

    2012-01-01

    •NO is considered to be a key macrophage-derived cytotoxic effector during Trypanosoma cruzi infection. On the other hand, the microbicidal properties of reactive oxygen species (ROS) are well recognized, but little importance has been attributed to them during in vivo infection with T. cruzi. In order to investigate the role of ROS in T. cruzi infection, mice deficient in NADPH phagocyte oxidase (gp91phox −/− or phox KO) were infected with Y strain of T. cruzi and the course of infection was followed. phox KO mice had similar parasitemia, similar tissue parasitism and similar levels of IFN-γ and TNF in serum and spleen cell culture supernatants, when compared to wild-type controls. However, all phox KO mice succumbed to infection between day 15 and 21 after inoculation with the parasite, while 60% of wild-type mice were alive 50 days after infection. Further investigation demonstrated increased serum levels of nitrite and nitrate (NOx) at day 15 of infection in phox KO animals, associated with a drop in blood pressure. Treatment with a NOS2 inhibitor corrected the blood pressure, implicating NOS2 in this phenomenon. We postulate that superoxide reacts with •NO in vivo, preventing blood pressure drops in wild type mice. Hence, whilst superoxide from phagocytes did not play a critical role in parasite control in the phox KO animals, its production would have an important protective effect against blood pressure decline during infection with T. cruzi. PMID:22348160

  16. Inhibition of polyphenol oxidases activity by various dipeptides.

    PubMed

    Girelli, Anna M; Mattei, Enrico; Messina, Antonella; Tarola, Anna M

    2004-05-19

    In an effort to develop natural and nontoxic inhibitors on the activity of mushroom polyphenol oxidase (PPO) the effect of various glycyl-dipeptides (GlyAsp, GlyGly, GlyHis, GlyLeu, GlyLys, GlyPhe, GlyPro, GlyTyr) was investigated. The inhibition study with dihydroxyphenylalanine (DOPA) as substrate is based on separation of the enzymatic reaction components by reversed phase HPLC and the UV detection of the dopachrome formed. The results have evidenced that several of tested dipeptides inhibited PPO activity in the range of 20-40% while GlyPro and GlyLeu had no effect. The study has also permitted the characterization of the following kinetic pattern: a linear-mixed-type mechanism for GlyAsp, GlyGly, GlyLys, and GlyPhe and a hyperbolic-mixed-type for GlyTyr. It was not possible to identify the inhibition mechanism for GlyHis, although it affects PPO activity. In addition the effects of GlyAsp, GlyLys and GlyHis were evaluated for lessening the browning of fresh Golden Delicious apple and Irish White Skinned potato. The effectiveness of such inhibitors was determined by the difference between the colors observed in the dipeptide-treated sample and the controls using the color space CIE-Lab system. The % browning inhibition on potato (20-50%) was greater than of apple (20-30%) by the all tested dipeptides. Only GlyLys presented the significant value of 50%.

  17. Salicylic acid inhibits enzymatic browning of fresh-cut Chinese chestnut (Castanea mollissima) by competitively inhibiting polyphenol oxidase.

    PubMed

    Zhou, Dan; Li, Lin; Wu, Yanwen; Fan, Junfeng; Ouyang, Jie

    2015-03-15

    The inhibitory effect and associated mechanisms of salicylic acid (SA) on the browning of fresh-cut Chinese chestnut were investigated. Shelled and sliced chestnuts were immersed in different concentrations of an SA solution, and the browning of the chestnut surface and interior were inhibited. The activities of polyphenol oxidase (PPO) and peroxidase (POD) extracted from chestnuts were measured in the presence and absence of SA. SA at concentrations higher than 0.3g/L delayed chestnut browning by significantly inhibiting the PPO activity (P<0.01), and the POD activity was not significantly affected (P>0.05). The binding and inhibition modes of SA with PPO and POD, determined by AUTODOCK 4.2 and Lineweaver-Burk plots, respectively, established SA as a competitive inhibitor of PPO. Copyright © 2014 Elsevier Ltd. All rights reserved.

  18. Capsule Influences the Deposition of Critical Complement C3 Levels Required for the Killing of Burkholderia pseudomallei via NADPH-Oxidase Induction by Human Neutrophils

    PubMed Central

    Woodman, Michael E.; Worth, Randall G.; Wooten, R. Mark

    2012-01-01

    Burkholderia pseudomallei is the causative agent of melioidosis and is a major mediator of sepsis in its endemic areas. Because of the low LD50 via aerosols and resistance to multiple antibiotics, it is considered a Tier 1 select agent by the CDC and APHIS. B. pseudomallei is an encapsulated bacterium that can infect, multiply, and persist within a variety of host cell types. In vivo studies suggest that macrophages and neutrophils are important for controlling B. pseudomallei infections, however few details are known regarding how neutrophils respond to these bacteria. Our goal is to describe the capacity of human neutrophils to control highly virulent B. pseudomallei compared to the relatively avirulent, acapsular B. thailandensis using in vitro analyses. B. thailandensis was more readily phagocytosed than B. pseudomallei, but both displayed similar rates of persistence within neutrophils, indicating they possess similar inherent abilities to escape neutrophil clearance. Serum opsonization studies showed that both were resistant to direct killing by complement, although B. thailandensis acquired significantly more C3 on its surface than B. pseudomallei, whose polysaccharide capsule significantly decreased the levels of complement deposition on the bacterial surface. Both Burkholderia species showed significantly enhanced uptake and killing by neutrophils after critical levels of C3 were deposited. Serum-opsonized Burkholderia induced a significant respiratory burst by neutrophils compared to unopsonized bacteria, and neutrophil killing was prevented by inhibiting NADPH-oxidase. In summary, neutrophils can efficiently kill B. pseudomallei and B. thailandensis that possess a critical threshold of complement deposition, and the relative differences in their ability to resist surface opsonization may contribute to the distinct virulence phenotypes observed in vivo. PMID:23251706

  19. Inhibition of polyamine and spermine oxidases by polyamine analogues.

    PubMed

    Bianchi, Marzia; Polticelli, Fabio; Ascenzi, Paolo; Botta, Maurizio; Federico, Rodolfo; Mariottini, Paolo; Cona, Alessandra

    2006-03-01

    Polyamine oxidase (PAO) and spermine oxidase (SMO) are involved in the catabolism of polyamines--basic regulators of cell growth and proliferation. The discovery of selective inhibitors of PAO and SMO represents an important tool in studying the involvement of these enzymes in polyamine homeostasis and a starting point for the development of novel antineoplastic drugs. Here, a comparative study on murine PAO (mPAO) and SMO (mSMO) inhibition by the polyamine analogues 1,8-diaminooctane, 1,12-diaminododecane, N-prenylagmatine (G3), guazatine and N,N1-bis(2,3-butadienyl)-1,4-butanediamine (MDL72527) is reported. Interestingly, 1,12-Diaminododecane and G3 behave as specific inhibitors of mPAO, values of K(i) for mPAO inhibition being lower than those for mSMO inactivation by several orders of magnitude. The analysis of molecular models of mPAO and mSMO indicates a significant reduction of the hydrophobic pocket located in maize PAO (MPAO) at the wider catalytic tunnel opening. This observation provides a rationale to explain the lower affinity displayed by G3, guazatine and MDL72527 for mPAO and mSMO as compared to MPAO. The different behaviour displayed by 1,12-diaminododecane towards mPAO and mSMO reveals the occurrence of basic differences in the ligand binding mode of the two enzymes, the first enzyme interacting mainly with substrate secondary amino groups and the second one with substrate primary amino groups. Thus, the data reported here provide the basis for the development of novel and selective inhibitors able to discriminate between mammalian SMO and PAO activities.

  20. Oxidation of Са2+-Binding Domain of NADPH Oxidase 5 (NOX5): Toward Understanding the Mechanism of Inactivation of NOX5 by ROS.

    PubMed

    Petrushanko, Irina Yu; Lobachev, Vladimir M; Kononikhin, Alexey S; Makarov, Alexander A; Devred, Francois; Kovacic, Hervé; Kubatiev, Aslan A; Tsvetkov, Philipp O

    2016-01-01

    NOX5 protein, one of the most active generators of reactive oxygen species (ROS), plays an important role in many processes, including regulation of cell growth, death and differentiation. Because of its central role in ROS generation, it needs to be tightly regulated to guarantee cellular homeostasis. Contrary to other members of NADPH-oxidases family, NOX5 has its own regulatory calcium-binding domain and thus could be activated directly by calcium ions. While several mechanisms of activation have been described, very little is known about the mechanisms that could prevent the overproduction of ROS by NOX5. In the present study using calorimetric methods and circular dichroism we found that oxidation of cysteine and methionine residues of NOX5 decreases binding of Ca2+ ions and perturbs both secondary and tertiary structure of protein. Our data strongly suggest that oxidation of calcium-binding domain of NOX5 could be implicated in its inactivation, serving as a possible defense mechanism against oxidative stress.

  1. The separate and combined effects of monoamine oxidase inhibition and nicotine on P50 sensory gating.

    PubMed

    Smith, Dylan M; Fisher, Derek; Blier, Pierre; Illivitsky, Vadim; Knott, Verner

    2015-06-01

    The cognitive effects of nicotine in humans remain a topic of great interest, due to the continued prevalence of cigarette smoking in society as well as the hypothesis that cognitively impaired populations such as schizophrenia patients use nicotine as a means of self-medicating against deficits of sensory gating. However, chronic smoking can predispose individuals to robust monoamine oxidase (MAO) inhibition, and thus far, the effect of MAO inhibition on human sensory gating is unknown. In this study, we investigated the effects of both nicotine (6-mg gum) and pharmacologically induced MAO-A inhibition via moclobemide (75 mg) on P50 event-related potential-indexed sensory gating in a sample of 24 healthy non-smoking males. Ratio score (rP50) measured gating revealed significant improvement in auditory stimulus suppression after combined nicotine and MAO-A inhibition compared to placebo and to the nicotine-alone condition. This nicotine + MAO-A inhibition-induced efficient gating was consistent regardless of participants' baseline (placebo) gating efficiency, despite the observation that nicotine in the absence of MAO-A inhibition exhibited a detrimental effect on gating in participants with high baseline suppression ratios. Nicotine and monoamine oxidase-inhibiting agents in tobacco smoke appear to exert a synergistic effect on sensory gating, which may contribute to the elevated dependence rates seen in populations with cognitive deficits such as schizophrenia.

  2. Bioreduction with Efficient Recycling of NADPH by Coupled Permeabilized Microorganisms▿

    PubMed Central

    Zhang, Wei; O'Connor, Kevin; Wang, Daniel I. C.; Li, Zhi

    2009-01-01

    The glucose dehydrogenase (GDH) from Bacillus subtilis BGSC 1A1 was cloned and functionally expressed in Escherichia coli BL21(pGDH1) and XL-1 Blue(pGDH1). Controlled permeabilization of recombinant E. coli BL21 and XL-1 Blue with EDTA-toluene under optimized conditions resulted in permeabilized cells with specific activities of 61 and 14 U/g (dry weight) of cells, respectively, for the conversion of NADP+ to NADPH upon oxidation of glucose. The permeabilized recombinant strains were more active than permeabilized B. subtilis BGSC 1A1, did not exhibit NADPH/NADH oxidase activity, and were useful for regeneration of both NADH and NADPH. Coupling of permeabilized cells of Bacillus pumilus Phe-C3 containing an NADPH-dependent ketoreductase and an E. coli recombinant expressing GDH as a novel biocatalytic system allowed enantioselective reduction of ethyl 3-keto-4,4,4-trifluorobutyrate with efficient recycling of NADPH; a total turnover number (TTN) of 4,200 mol/mol was obtained by using E. coli BL21(pGDH1) as the cofactor-regenerating microorganism with initial addition of 0.005 mM NADP+. The high TTN obtained is in the practical range for producing fine chemicals. Long-term stability of the permeabilized cell couple and a higher product concentration were demonstrated by 68 h of bioreduction of ethyl 3-keto-4,4,4-trifluorobutyrate with addition of 0.005 mM NADP+ three times; 50.5 mM (R)-ethyl 3-hydroxy-4,4,4-trifluorobutyrate was obtained with 95% enantiomeric excess, 84% conversion, and an overall TTN of 3,400 mol/mol. Our method results in practical synthesis of (R)-ethyl 3-hydroxy-4,4,4-trifluorobutyrate, and the principle described here is generally applicable to other microbial reductions with cofactor recycling. PMID:19047388

  3. Antioxidant Protection of NADPH-Depleted Oligodendrocyte Precursor Cells Is Dependent on Supply of Reduced Glutathione.

    PubMed

    Kilanczyk, Ewa; Saraswat Ohri, Sujata; Whittemore, Scott R; Hetman, Michal

    2016-08-01

    The pentose phosphate pathway is the main source of NADPH, which by reducing oxidized glutathione, contributes to antioxidant defenses. Although oxidative stress plays a major role in white matter injury, significance of NADPH for oligodendrocyte survival has not been yet investigated. It is reported here that the NADPH antimetabolite 6-amino-NADP (6AN) was cytotoxic to cultured adult rat spinal cord oligodendrocyte precursor cells (OPCs) as well as OPC-derived oligodendrocytes. The 6AN-induced necrosis was preceded by increased production of superoxide, NADPH depletion, and lower supply of reduced glutathione. Moreover, survival of NADPH-depleted OPCs was improved by the antioxidant drug trolox. Such cells were also protected by physiological concentrations of the neurosteroid dehydroepiandrosterone (10(-8) M). The protection by dehydroepiandrosterone was associated with restoration of reduced glutathione, but not NADPH, and was sensitive to inhibition of glutathione synthesis. A similar protective mechanism was engaged by the cAMP activator forskolin or the G protein-coupled estrogen receptor (GPER/GPR30) ligand G1. Finally, treatment with the glutathione precursor N-acetyl cysteine reduced cytotoxicity of 6AN. Taken together, NADPH is critical for survival of OPCs by supporting their antioxidant defenses. Consequently, injury-associated inhibition of the pentose phosphate pathway may be detrimental for the myelination or remyelination potential of the white matter. Conversely, steroid hormones and cAMP activators may promote survival of NADPH-deprived OPCs by increasing a NADPH-independent supply of reduced glutathione. Therefore, maintenance of glutathione homeostasis appears as a critical effector mechanism for OPC protection against NADPH depletion and preservation of the regenerative potential of the injured white matter. © The Author(s) 2016.

  4. NADPH Oxidase-Derived H2O2 Contributes to Angiotensin II-Induced Aldosterone Synthesis in Human and Rat Adrenal Cortical Cells

    PubMed Central

    Rajamohan, Senthilkumar B.; Raghuraman, Gayatri; Prabhakar, Nanduri R.

    2012-01-01

    Abstract Background The Renin-Angiotensin-Aldosterone-System plays a pivotal role in hypertension. Angiotensin II (Ang II) is a major regulator of aldosterone synthesis and secretion, and it is known to facilitate reactive oxygen species (ROS) generation in many cell types. Aims: Here, we assessed the role of ROS signaling in Ang II-induced aldosterone synthesis by focusing on the regulation of aldosterone synthase (CYP11B2), a cytochrome P450 oxidase that catalyzes the final step in aldosterone biosynthetic pathway. Results: Ang II increased CYP11B2 activity, mRNA and protein with a concomitant elevation of 6-Carboxy- 2′,7′-dichlorodihydrofluorescein diacetate fluorescence, malondialdehyde and protein carbonyl levels (indices of ROS), NADPH oxidase (Nox) activity, and H2O2 levels in human and rat adrenal cortical cells. The expression of nuclear receptor related 1 protein, a transcription factor known to regulate CYP11B2 expression, was also augmented by Ang II. These Ang II-evoked effects were either abolished or attenuated by pretreatment of cells with either Ang II type I receptor (AT1R) antagonist, or antioxidants or Nox inhibitor or siRNA silencing of Nox1, 2 and 4, or inhibitors of phospholipase C and protein kinase C. Exogenous H2O2 mimicked the facilitatory effects of Ang II on CYP11B2 activity, mRNA, and protein expression, and these changes were significantly reduced by PEG-catalase. Innovation: ROS, particularly H2O2, is identified as a key regulator of aldosterone production. Conclusion: Our results suggest that Ang II facilitates CYP11B2 activity and the ensuing aldosterone production via activation of AT1R-Nox-H2O2 signaling pathway. Antioxid. Redox Signal. 17, 445–459. PMID:22214405

  5. A role for NADPH oxidase 4 in the activation of vascular endothelial cells by oxidized phospholipids

    PubMed Central

    Lee, Sangderk; Gharavi, Nima M.; Honda, Henry; Chang, Irene; Kim, Brandon; Jen, Nelson; Li, Rongsong; Zimman, Alejandro; Berliner, Judith A.

    2009-01-01

    Previous studies from our group have demonstrated that oxidized 1-palmitoyl-2-arachidonyl-sn-glycerol-3-phosphocholine (Ox-PAPC) activates over 1000 genes in human aortic endothelial cell (HAEC). Prominent among these are genes regulating inflammation, cholesterol homeostasis, antioxidant enzymes, and the unfolded protein response. Previous studies from our lab and others suggested that transcriptional regulation by Ox-PAPC may be controlled, at least in part, by reactive oxygen species (ROS). We now present evidence that Ox-PAPC activation of NADPH oxidase 4 (NOX4) is responsible for the regulation of two of these important groups of genes: those controlling inflammation and sterol regulation. Our data demonstrate that Ox-PAPC increases reactive oxygen species formation in HAEC as seen by DCF fluorescence. NOX4 is the major molecule responsible for this increase since downregulation of NOX4 and its components (p22phox and rac1) blocked the Ox-PAPC effect. Our data show that Ox-PAPC did not change NOX4 transcription levels but did induce recruitment of rac1 to the membrane for NOX4 activation. We present evidence that vascular endothelial growth factor receptor 2 (VEGFR2) activation is responsible for rac1 recruitment to the membrane. Finally, we demonstrate that knockdown of NOX4 and its components rac1 and p22phox decrease Ox-PAPC induction of inflammatory and sterol regulatory genes, but do not affect Ox-PAPC transcriptional regulation of other gene of antioxidant and unfolded protein response. In summary, we have identified a VEGFR2/NOX4 regulatory pathway by which Ox-PAPC controls important endothelial functions. PMID:19375500

  6. The cytochrome bd oxidase of Escherichia coli prevents respiratory inhibition by endogenous and exogenous hydrogen sulfide

    PubMed Central

    Korshunov, Sergey; Imlay, Karin R. C.; Imlay, James A.

    2016-01-01

    Summary When sulfur compounds are scarce or difficult to process, E. coli adapts by inducing the high-level expression of sulfur-compound importers. If cystine then becomes available, the cystine is rapidly overimported and reduced, leading to a burgeoning pool of intracellular cysteine. Most of the excess cysteine is exported, but some is adventitiously degraded, with the consequent release of sulfide. Sulfide is a potent ligand of copper and heme moieties, raising the prospect that it interferes with enzymes. We observed that when cystine was provided and sulfide levels rose, E. coli became strictly dependent upon cytochrome bd oxidase for continued respiration. Inspection revealed that low-micromolar levels of sulfide inhibited the proton-pumping cytochrome bo oxidase that is regarded as the primary respiratory oxidase. In the absence of the back-up cytochrome bd oxidase, growth failed. Exogenous sulfide elicited the same effect. The potency of sulfide was enhanced when oxygen concentrations were low. Natural oxic-anoxic interfaces are often sulfidic, including the intestinal environment where E. coli dwells. We propose that the sulfide resistance of the cytochrome bd oxidase is a key trait that permits respiration in such habitats. PMID:26991114

  7. Rho-kinase inhibitor and nicotinamide adenine dinucleotide phosphate oxidase inhibitor prevent impairment of endothelium-dependent cerebral vasodilation by acute cigarette smoking in rats.

    PubMed

    Iida, Hiroki; Iida, Mami; Takenaka, Motoyasu; Fukuoka, Naokazu; Dohi, Shuji

    2008-06-01

    We previously reported that acute cigarette smoking can cause a dysfunction of endothelium-dependent vasodilation in cerebral vessels, and that blocking the angiotensin II (Ang II) type 1 (AT1) receptor with valsartan prevented this impairment. Our aim was to investigate the effects of a Rho-kinase inhibitor (fasudil) and a Nicotinamide Adenine Dinucleotide PHosphate (NADPH) oxidase inhibitor (apocynin) on smoking-induced endothelial dysfunction in cerebral arterioles. In Sprague-Dawley rats, we used a closed cranial window preparation to measure changes in pial vessel diameters following topical acetylcholine (ACh) before smoking. After one-minute smoking, we again examined the arteriolar responses to ACh. Finally, after intravenous fasudil or apocynin pre-treatment we re-examined the vasodilator responses to topical ACh (before and after cigarette smoking). Under control conditions, cerebral arterioles were dose-dependently dilated by topical ACh (10(-6) M and 10(-5) M). One hour after a one-minute smoking (1 mg-nicotine cigarette), 10(-5) M ACh constricted cerebral arterioles. However, one hour after a one-minute smoking, 10(-5) M ACh dilated cerebral pial arteries both in the fasudil pre-treatment and the apocynin pre-treatment groups, responses that were significantly different from those obtained without fasudil or apocynin pre-treatment. Thus, inhibition of Rho-kinase and NADPH oxidase activities may prevent the above smoking-induced impairment of endothelium-dependent vasodilation.

  8. Hypertonic Saline Suppresses NADPH Oxidase-Dependent Neutrophil Extracellular Trap Formation and Promotes Apoptosis.

    PubMed

    Nadesalingam, Ajantha; Chen, Jacky H K; Farahvash, Armin; Khan, Meraj A

    2018-01-01

    Tonicity of saline (NaCl) is important in regulating cellular functions and homeostasis. Hypertonic saline is administered to treat many inflammatory diseases, including cystic fibrosis. Excess neutrophil extracellular trap (NET) formation, or NETosis, is associated with many pathological conditions including chronic inflammation. Despite the known therapeutic benefits of hypertonic saline, its underlying mechanisms are not clearly understood. Therefore, we aimed to elucidate the effects of hypertonic saline in modulating NETosis. For this purpose, we purified human neutrophils and induced NETosis using agonists such as diacylglycerol mimetic phorbol myristate acetate (PMA), Gram-negative bacterial cell wall component lipopolysaccharide (LPS), calcium ionophores (A23187 and ionomycin from Streptomyces conglobatus ), and bacteria ( Pseudomonas aeruginosa and Staphylococcus aureus ). We then analyzed neutrophils and NETs using Sytox green assay, immunostaining of NET components and apoptosis markers, confocal microscopy, and pH sensing reagents. This study found that hypertonic NaCl suppresses nicotinamide adenine dinucleotide phosphate oxidase (NADPH2 or NOX2)-dependent NETosis induced by agonists PMA, Escherichia coli LPS (0111:B4 and O128:B12), and P. aeruginosa . Hypertonic saline also suppresses LPS- and PMA- induced reactive oxygen species production. It was determined that supplementing H 2 O 2 reverses the suppressive effect of hypertonic saline on NOX2-dependent NETosis. Many of the aforementioned suppressive effects were observed in the presence of equimolar concentrations of choline chloride and osmolytes (d-mannitol and d-sorbitol). This suggests that the mechanism by which hypertonic saline suppresses NOX2-dependent NETosis is via neutrophil dehydration. Hypertonic NaCl does not significantly alter the intracellular pH of neutrophils. We found that hypertonic NaCl induces apoptosis while suppressing NOX2-dependent NETosis. In contrast, hypertonic

  9. Inhibition of rat mammary microsomal oxidation of ethanol to acetaldehyde by plant polyphenols.

    PubMed

    Maciel, María Eugenia; Castro, José Alberto; Castro, Gerardo Daniel

    2011-07-01

    We previously reported that the microsomal fraction from rat mammary tissue is able to oxidize ethanol to acetaldehyde, a mutagenic-carcinogenic metabolite, depending on the presence of NADPH and oxygen but not inhibited by carbon monoxide or other cytochrome P450 inhibitors. The process was strongly inhibited by diphenyleneiodonium, a known inhibitor of NADPH oxidase, and by nordihydroguaiaretic acid, an inhibitor of lipoxygenases. This led us to suggest that both enzymes could be involved. With the purpose of identifying natural compounds present in food with the ability to decrease the production of acetaldehyde in mammary tissue, in the present studies, several plant polyphenols having inhibitory effects on lipoxygenases and of antioxidant nature were tested as potential inhibitors of the rat mammary tissue microsomal pathway of ethanol oxidation. We included in the present screening study 32 polyphenols having ready availability and that were also tested against the rat mammary tissue cytosolic metabolism of ethanol to acetaldehyde. Several polyphenols were also able to inhibit the microsomal ethanol oxidation at concentrations as low was 10-50 μM. The results of these screening experiments suggest the potential of several plant polyphenols to prevent in vivo production and accumulation of acetaldehyde in mammary tissue.

  10. Xanthine Oxidase Inhibition by Febuxostat Attenuates Experimental Atherosclerosis in Mice

    PubMed Central

    Nomura, Johji; Busso, Nathalie; Ives, Annette; Matsui, Chieko; Tsujimoto, Syunsuke; Shirakura, Takashi; Tamura, Mizuho; Kobayashi, Tsunefumi; So, Alexander; Yamanaka, Yoshihiro

    2014-01-01

    Atherosclerosis is a chronic inflammatory disease due to lipid deposition in the arterial wall. Multiple mechanisms participate in the inflammatory process, including oxidative stress. Xanthine oxidase (XO) is a major source of reactive oxygen species (ROS) and has been linked to the pathogenesis of atherosclerosis, but the underlying mechanisms remain unclear. Here, we show enhanced XO expression in macrophages in the atherosclerotic plaque and in aortic endothelial cells in ApoE−/− mice, and that febuxostat, a highly potent XO inhibitor, suppressed plaque formation, reduced arterial ROS levels and improved endothelial dysfunction in ApoE−/− mice without affecting plasma cholesterol levels. In vitro, febuxostat inhibited cholesterol crystal-induced ROS formation and inflammatory cytokine release in murine macrophages. These results demonstrate that in the atherosclerotic plaque, XO-mediated ROS formation is pro-inflammatory and XO-inhibition by febuxostat is a potential therapy for atherosclerosis. PMID:24686534

  11. Pro-inflammatory effects of interleukin-17A on vascular smooth muscle cells involve NAD(P)H- oxidase derived reactive oxygen species.

    PubMed

    Pietrowski, Eweline; Bender, Bianca; Huppert, Jula; White, Robin; Luhmann, Heiko J; Kuhlmann, Christoph R W

    2011-01-01

    T cells are known for their contribution to the inflammatory element of atherosclerosis. Recently, it has been demonstrated that the Th17 derived cytokine IL-17 is involved in the pro-inflammatory response of vascular smooth muscle cells (VSMC). The aim of the present study was to examine whether reactive oxygen species (ROS) might be involved in this context. The effect of IL-17A on ROS generation was examined using the fluorescent dye 2'7'-dichlorodihydrofluorescein (H(2)DCF) in primary murine VSMC. IL-17A induced an increase in H(2)DCF fluorescence in VSMC, and this effect was blocked by the NAD(P)H-oxidase inhibitor apocynin and siRNA targeting Nox2. The p38-MAPK inhibitors SB203580 and SB202190 dose-dependently reduced the IL-17A induced ROS production. The IL-17A induced release of the pro-inflammatory cytokines IL-6, G-CSF, GM-CSF and MCP-1 from VSMC, as detected by the Luminex technology, was completely abolished by NAD(P)H-oxidase inhibition. Taken together, our data indicate that IL-17A causes the NAD(P)H-oxidase dependent generation of ROS leading to a pro-inflammatory activation of VSMC. Copyright © 2010 S. Karger AG, Basel.

  12. Role of VPO1, a newly identified heme-containing peroxidase, in ox-LDL induced endothelial cell apoptosis

    PubMed Central

    Bai, Yong-Ping; Hu, Chang-Ping; Yuan, Qiong; Peng, Jun; Shi, Rui-Zheng; Yang, Tian-Lun; Cao, Ze-Hong; Li, Yuan-Jian; Cheng, Guangjie; Zhang, Guo-Gang

    2013-01-01

    Myeloperoxidase (MPO) is an important enzyme involved in the genesis and development of atherosclerosis. Vascular peroxidase 1 (VPO1) is a newly discovered member of the peroxidase family that is mainly expressed in vascular endothelial cells and smooth muscle cells and has structural characteristics and biological activity similar to those of MPO. Our specific aims were to explore the effects of VPO1 on endothelial cell apoptosis induced by oxidized low-density lipoprotein (ox-LDL) and the underlying mechanisms. The results showed that ox-LDL induced endothelial cell apoptosis and the expression of VPO1 in endothelial cells in a concentration- and time-dependent manner concomitant with increased intracellular reactive oxygen species (ROS) and hypochlorous acid (HOCl) generation, and up-regulated protein expression of the NADPH oxidase gp91phox subunit and phosphorylation of p38 MAPK. All these effects of ox-LDL were inhibited by VPO1 gene silencing and NADPH oxidase gp91phox subunit gene silencing or by pretreatment with the NADPH oxidase inhibitor apocynin or diphenyliodonium. The p38 MAPK inhibitor SB203580 or the caspase-3 inhibitor DEVD-CHO significantly inhibited ox-LDL-induced endothelial cell apoptosis, but had no effect on intracellular ROS and HOCl generation or the expression of NADPH oxidase gp91phox subunit or VPO1. Collectively, these findings suggest for the first time that VPO1 plays a critical role in ox-LDL-induced endothelial cell apoptosis and that there is a positive feedback loop between VPO1/HOCl and the now-accepted dogma that the NADPH oxidase/ROS/p38 MAPK/caspase-3 pathway is involved in ox-LDL-induced endothelial cell apoptosis. PMID:21820048

  13. The Role of Aldehyde Oxidase and Xanthine Oxidase in the Biotransformation of a Novel Negative Allosteric Modulator of Metabotropic Glutamate Receptor Subtype 5

    PubMed Central

    Morrison, Ryan D.; Blobaum, Anna L.; Byers, Frank W.; Santomango, Tammy S.; Bridges, Thomas M.; Stec, Donald; Brewer, Katrina A.; Sanchez-Ponce, Raymundo; Corlew, Melany M.; Rush, Roger; Felts, Andrew S.; Manka, Jason; Bates, Brittney S.; Venable, Daryl F.; Rodriguez, Alice L.; Jones, Carrie K.; Niswender, Colleen M.; Conn, P. Jeffrey; Lindsley, Craig W.; Emmitte, Kyle A.

    2012-01-01

    Negative allosteric modulation (NAM) of metabotropic glutamate receptor subtype 5 (mGlu5) represents a therapeutic strategy for the treatment of childhood developmental disorders, such as fragile X syndrome and autism. VU0409106 emerged as a lead compound within a biaryl ether series, displaying potent and selective inhibition of mGlu5. Despite its high clearance and short half-life, VU0409106 demonstrated efficacy in rodent models of anxiety after extravascular administration. However, lack of a consistent correlation in rat between in vitro hepatic clearance and in vivo plasma clearance for the biaryl ether series prompted an investigation into the biotransformation of VU0409106 using hepatic subcellular fractions. An in vitro appraisal in rat, monkey, and human liver S9 fractions indicated that the principal pathway was NADPH-independent oxidation to metabolite M1 (+16 Da). Both raloxifene (aldehyde oxidase inhibitor) and allopurinol (xanthine oxidase inhibitor) attenuated the formation of M1, thus implicating the contribution of both molybdenum hydroxylases in the biotransformation of VU0409106. The use of 18O-labeled water in the S9 experiments confirmed the hydroxylase mechanism proposed, because 18O was incorporated into M1 (+18 Da) as well as in a secondary metabolite (M2; +36 Da), the formation of which was exclusively xanthine oxidase-mediated. This unusual dual and sequential hydroxylase metabolism was confirmed in liver S9 and hepatocytes of multiple species and correlated with in vivo data because M1 and M2 were the principal metabolites detected in rats administered VU0409106. An in vitro-in vivo correlation of predicted hepatic and plasma clearance was subsequently established for VU0409106 in rats and nonhuman primates. PMID:22711749

  14. Lycopene inhibits reactive oxygen species production in SK-Hep-1 cells and attenuates acetaminophen-induced liver injury in C57BL/6 mice.

    PubMed

    Bandeira, Ana Carla Balthar; da Silva, Talita Prato; de Araujo, Glaucy Rodrigues; Araujo, Carolina Morais; da Silva, Rafaella Cecília; Lima, Wanderson Geraldo; Bezerra, Frank Silva; Costa, Daniela Caldeira

    2017-02-01

    Our aim was to investigate the antioxidant potential of lycopene in different experimental liver models: in vitro, to evaluate the influence of lycopene on reactive oxygen species (ROS) production mediated by the PKC pathway and in vivo, to evaluate the protective effects of lycopene in an experimental model of hepatotoxicity. The in vitro study assessed the lycopene antioxidant potential by the quantification of ROS production in SK-Hep-1 cells unstimulated or stimulated by an activator of the PKC pathway. The role of NADPH oxidase was evaluated by measuring its inhibition potential using an inhibitor of this enzyme. In the in vivo study, male C57BL/6 mice received lycopene (10 or 100 mg/kg by oral gavage) and 1 h later, acetaminophen (APAP) (500 mg/kg) was administrated. Lycopene decreased ROS production in SK-Hep-1 cells through inhibition of NADPH oxidase, brought about in the PKC pathway. Lycopene improved hepatotoxicity acting as an antioxidant, reduced GSSG and regulated tGSH and CAT levels, reduced oxidative damage primarily by decreasing protein carbonylation, promoted the downregulation of MMP-2 and reduced areas of necrosis improving the general appearance of the lesion in C57BL/6 mice. Lycopene is a natural compound that was able to inhibit the production of ROS in vitro and mitigate the damage caused by APAP overdose in vivo. Copyright © 2016 Elsevier Ireland Ltd. All rights reserved.

  15. Microvascular Endothelial Dysfunction in Sedentary, Obese Humans is mediated by NADPH Oxidase; Influence of Exercise Training

    PubMed Central

    La Favor, Justin D.; Dubis, Gabriel S.; Yan, Huimin; White, Joseph D.; Nelson, Margaret A.M.; Anderson, Ethan J.; Hickner, Robert C.

    2016-01-01

    Objective The objectives of this study were to determine the impact of in vivo reactive oxygen species (ROS) on microvascular endothelial function in obese human subjects and to determine the efficacy of an aerobic exercise intervention on alleviating obesity-associated dysfunctionality. Approach and Results Young, sedentary men and women were divided into lean (BMI 18–25; n=14), intermediate (BMI 28–32.5; n=13), and obese (BMI 33–40; n=15) groups. A novel microdialysis technique was utilized to detect elevated interstitial hydrogen peroxide (H2O2) and superoxide levels in the vastus lateralis of obese compared to both lean and intermediate subjects. Nutritive blood flow was monitored in the vastus lateralis via the microdialysis-ethanol technique. A decrement in acetylcholine-stimulated blood flow revealed impaired microvascular endothelial function in the obese subjects. Perfusion of apocynin, an NADPH oxidase (Nox) inhibitor, lowered (normalized) H2O2 and superoxide levels and reversed microvascular endothelial dysfunction in obese subjects. Following 8-weeks of exercise, H2O2 levels were decreased in the obese subjects and microvascular endothelial function in these subjects was restored to levels similar to lean subjects. Skeletal muscle protein expression of the Nox subunits p22phox, p47phox, and p67phox were increased in obese relative to lean subjects, where p22phox and p67phox expression was attenuated by exercise training in obese subjects. Conclusions This study implicates Nox as a source of excessive ROS production in skeletal muscle of obese individuals, and links excessive Nox derived ROS to microvascular endothelial dysfunction in obesity. Furthermore, aerobic exercise training proved to be an effective strategy for alleviating these maladies. PMID:27765769

  16. NADPH oxidase-mediated redox signal contributes to lipoteichoic acid-induced MMP-9 upregulation in brain astrocytes

    PubMed Central

    2012-01-01

    Background Lipoteichoic acid (LTA) is a component of gram-positive bacterial cell walls and may be elevated in the cerebrospinal fluid of patients suffering from meningitis. Among matrix metalloproteinases (MMPs), MMP-9 has been observed in patients with brain inflammatory diseases and may contribute to the pathology of brain diseases. Moreover, several studies have suggested that increased oxidative stress is implicated in the pathogenesis of brain inflammation and injury. However, the molecular mechanisms underlying LTA-induced redox signal and MMP-9 expression in brain astrocytes remain unclear. Objective Herein we explored whether LTA-induced MMP-9 expression was mediated through redox signals in rat brain astrocytes (RBA-1 cells). Methods Upregulation of MMP-9 by LTA was evaluated by zymographic and RT-PCR analyses. Next, the MMP-9 regulatory pathways were investigated by pretreatment with pharmacological inhibitors or transfection with small interfering RNAs (siRNAs), Western blotting, and chromatin immunoprecipitation (ChIP)-PCR and promoter activity reporter assays. Moreover, we determined the cell functional changes by migration assay. Results These results showed that LTA induced MMP-9 expression via a PKC(α)-dependent pathway. We further demonstrated that PKCα stimulated p47phox/NADPH oxidase 2 (Nox2)-dependent reactive oxygen species (ROS) generation and then activated the ATF2/AP-1 signals. The activated-ATF2 bound to the AP-1-binding site of MMP-9 promoter, and thereby turned on MMP-9 gene transcription. Additionally, the co-activator p300 also contributed to these responses. Functionally, LTA-induced MMP-9 expression enhanced astrocytic migration. Conclusion These results demonstrated that in RBA-1 cells, activation of ATF2/AP-1 by the PKC(α)-mediated Nox(2)/ROS signals is essential for upregulation of MMP-9 and cell migration enhanced by LTA. PMID:22643046

  17. Effects of stevia on synaptic plasticity and NADPH oxidase level of CNS in conditions of metabolic disorders caused by fructose.

    PubMed

    Chavushyan, V A; Simonyan, K V; Simonyan, R M; Isoyan, A S; Simonyan, G M; Babakhanyan, M A; Hovhannisyian, L E; Nahapetyan, Kh H; Avetisyan, L G; Simonyan, M A

    2017-12-19

    Excess dietary fructose intake associated with metabolic syndrome and insulin resistance and increased risk of developing type 2 diabetes. Previous animal studies have reported that diabetic animals have significantly impaired behavioural and cognitive functions, pathological synaptic function and impaired expression of glutamate receptors. Correction of the antioxidant status of laboratory rodents largely prevents the development of fructose-induced plurimetabolic changes in the nervous system. We suggest a novel concept of efficiency of Stevia leaves for treatment of central diabetic neuropathy. By in vivo extracellular studies induced spike activity of hippocampal neurons during high frequency stimulation of entorhinal cortex, as well as neurons of basolateral amygdala to high-frequency stimulation of the hippocampus effects of Stevia rebaudiana Bertoni plant evaluated in synaptic activity in the brain of fructose-enriched diet rats. In the conditions of metabolic disorders caused by fructose, antioxidant activity of Stevia rebaudiana was assessed by measuring the NOX activity of the hippocampus, amygdala and spinal cord. In this study, the characteristic features of the metabolic effects of dietary fructose on synaptic plasticity in hippocampal neurons and basolateral amygdala and the state of the NADPH oxidase (NOX) oxidative system of these brain formations are revealed, as well as the prospects for development of multitarget and polyfunctional phytopreparations (with adaptogenic, antioxidant, antidiabetic, nootropic activity) from native raw material of Stevia rebaudiana. Stevia modulates degree of expressiveness of potentiation/depression (approaches but fails to achieve the norm) by shifting the percentage balance in favor of depressor type of responses during high-frequency stimulation, indicating its adaptogenic role in plasticity of neural networks. Under the action of fructose an increase (3-5 times) in specific quantity of total fraction of NOX

  18. Paroxetine prevents loss of nigrostriatal dopaminergic neurons by inhibiting brain inflammation and oxidative stress in an experimental model of Parkinson's disease.

    PubMed

    Chung, Young C; Kim, Sang R; Jin, Byung K

    2010-07-15

    The present study examined whether the antidepressant paroxetine promotes the survival of nigrostriatal dopaminergic (DA) neurons in the 1-methyl-4-phenyl-1,2,3,6-tetrahydropyridine (MPTP) mouse model of Parkinson's disease. MPTP induced degeneration of nigrostriatal DA neurons and glial activation as visualized by tyrosine hydroxylase, macrophage Ag complex-1, and/or glial fibrillary acidic protein immunoreactivity. Real-time PCR, Western blotting, and immunohistochemistry showed upregulation of proinflammatory cytokines, activation of microglial NADPH oxidase and astroglial myeloperoxidase, and subsequent reactive oxygen species production and oxidative DNA damage in the MPTP-treated substantia nigra. Treatment with paroxetine prevented degeneration of nigrostriatal DA neurons, increased striatal dopamine levels, and improved motor function. This neuroprotection afforded by paroxetine was associated with the suppression of astroglial myeloperoxidase expression and/or NADPH oxidase-derived reactive oxygen species production and reduced expression of proinflammatory cytokines, including IL-1beta, TNF-alpha, and inducible NO synthase, by activated microglia. The present findings show that paroxetine may possess anti-inflammatory properties and inhibit glial activation-mediated oxidative stress, suggesting that paroxetine and its analogues may have therapeutic value in the treatment of aspects of Parkinson's disease related to neuroinflammation.

  19. Constitutive NADPH-dependent electron transferase activity of the Nox4 dehydrogenase domain.

    PubMed

    Nisimoto, Yukio; Jackson, Heather M; Ogawa, Hisamitsu; Kawahara, Tsukasa; Lambeth, J David

    2010-03-23

    NADPH oxidase 4 (Nox4) is constitutively active, while Nox2 requires the cytosolic regulatory subunits p47(phox) and p67(phox) and activated Rac with activation by phorbol 12-myristate 13-acetate (PMA). This study was undertaken to identify the domain on Nox4 that confers constitutive activity. Lysates from Nox4-expressing cells exhibited constitutive NADPH- but not NADH-dependent hydrogen peroxide production with a K(m) for NADPH of 55 +/- 10 microM. The concentration of Nox4 in cell lysates was estimated using Western blotting and allowed calculation of a turnover of approximately 200 mol of H(2)O(2) min(-1) (mol of Nox4)(-1). A chimeric protein (Nox2/4) consisting of the Nox2 transmembrane (TM) domain and the Nox4 dehydrogenase (DH) domain showed H(2)O(2) production in the absence of cytosolic regulatory subunits. In contrast, chimera Nox4/2, consisting of the Nox4 TM and Nox2 DH domains, exhibited PMA-dependent activation that required coexpression of regulatory subunits. Nox DH domains from several Nox isoforms were purified and evaluated for their electron transferase activities. Nox1 DH, Nox2 DH, and Nox5 DH domains exhibited barely detectable activities toward artificial electron acceptors, while the Nox4 DH domain exhibited significant rates of reduction of cytochrome c (160 min(-1), largely superoxide dismutase-independent), ferricyanide (470 min(-1)), and other electron acceptors (artificial dyes and cytochrome b(5)). Rates were similar to those observed for H(2)O(2) production by the Nox4 holoenzyme in cell lysates. The activity required added FAD and was seen with NADPH but not NADH. These results indicate that the Nox4 DH domain exists in an intrinsically activated state and that electron transfer from NADPH to FAD is likely to be rate-limiting in the NADPH-dependent reduction of oxygen by holo-Nox4.

  20. A comparison of cell proliferation in normal and neoplastic intestinal epithelia following either biogenic amine depletion or monoamine oxidase inhibition.

    PubMed

    Tutton, P J; Barkla, D H

    1976-08-11

    Epithelial cell proliferation was studied in the jejunum and in the colon of normal rats, in the colon of dimethylhydrazine-treated rats and in dimethylhydrazine-induced adenocarcinoma of the colon using a stathmokinetic technique. Estimates of cell proliferation rates in these four tissues were then repeated in animals which had been depleted of biogenic animes by treatment with reserpine and in animals whose monoamine oxidase was inhibited by treatment with nialamide. In amine-depleted animals cell proliferation essentially ceased in all four tissues examined. Inhibition of monoamine oxidase did not significantly influence cell proliferation in nonmalignant tissues but accelerated cell division in colonic tumours.

  1. Isolation, Identification, and Xanthine Oxidase Inhibition Activity of Alkaloid Compound from Peperomia pellucida

    NASA Astrophysics Data System (ADS)

    Fachriyah, E.; Ghifari, M. A.; Anam, K.

    2018-04-01

    The research of the isolation and xanthine oxidation inhibition activity of alkaloid compound from Peperomia pellucida has been carried out. Alkaloid extract is isolated by column chromatography and preparative TLC. Alkaloid isolate is identified spectroscopically by UV-Vis spectrophotometer, FT-IR, and LC-MS/MS. Xanthine oxidase inhibition activity is carried out by in vitro assay. The result showed that the alkaloid isolated probably has piperidine basic structure. The alkaloid isolate has N-H, C-H, C = C, C = O, C-N, C-O-C groups and the aromatic ring. The IC50 values of ethanol and alkaloid extract are 71.6658 ppm and 76.3318 ppm, respectively. Alkaloid extract of Peperomia pellucida showed higher activity than ethanol extract.

  2. Safflor yellow B suppresses angiotensin II-mediated human umbilical vein cell injury via regulation of Bcl-2/p22{sup phox} expression

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

    Wang, Chaoyun; He, Yanhao; Department of Pharmacology, Xi'an Jiaotong University School of Medicine, Key Laboratory of Environment and Genes Related to Disease, Ministry of Education, Xi'an, Shaanxi 710061

    Intracellular reactive oxygen species (ROS) are derived from nicotinamide adenine dinucleotide phosphate (NADPH) oxidase. Angiotensin II (Ang II) can cause endothelial dysfunction by promoting intracellular ROS generation. Safflor yellow B (SYB) effectively inhibits ROS generation by upregulating Bcl-2 expression. In this study, we examined the effects of SYB on Ang II-induced injury to human umbilical vein endothelial cells (HUVECs), and elucidated the roles of NADPH oxidase and Bcl-2. We treated cultured HUVECs with Ang II, SYB, and Bcl-2 siRNA, and determined NADPH oxidase activity and ROS levels. Furthermore, cellular and mitochondrial physiological states were evaluated, and the expression levels ofmore » target proteins were analyzed. Ang II significantly enhanced intracellular ROS levels, caused mitochondrial membrane dysfunction, and decreased cell viability, leading to apoptosis. This was associated with increased expression of AT1R and p22{sup phox}, increased NADPH oxidase activity, and an increased ratio of Bax/Bcl-2, leading to decreases in antioxidant enzyme activities, which were further strengthened after blocking Bcl-2. Compared to Ang II treatment alone, co-treatment with SYB significantly reversed HUVEC injury. Taken together, these results demonstrate that SYB could significantly protect endothelial cells from Ang II-induced cell damage, and that it does so by upregulating Bcl-2 expression and inhibiting ROS generation. - Highlights: • Angiotensin II depresses mitochondria physiological function. • Angiotensin II activates NADPH oxidase via up-regulating expresion of p22{sup phox}. • Bcl-2 plays a pivotal role in improving mitochondria function and regulates ROS level. • Inhibitor of Bcl-2 promotes angiotensin II mediated HUVEC injury. • SYB attenuates angiotensin II mediated HUVEC injury via up regulating Bcl-2 expression.« less

  3. Glucose-6-phosphate dehydrogenase and NADPH redox regulates cardiac myocyte L-type calcium channel activity and myocardial contractile function.

    PubMed

    Rawat, Dhwajbahadur K; Hecker, Peter; Watanabe, Makino; Chettimada, Sukrutha; Levy, Richard J; Okada, Takao; Edwards, John G; Gupte, Sachin A

    2012-01-01

    We recently demonstrated that a 17-ketosteroid, epiandrosterone, attenuates L-type Ca(2+) currents (I(Ca-L)) in cardiac myocytes and inhibits myocardial contractility. Because 17-ketosteroids are known to inhibit glucose-6-phosphate dehydrogenase (G6PD), the rate-limiting enzyme in the pentose phosphate pathway, and to reduce intracellular NADPH levels, we hypothesized that inhibition of G6PD could be a novel signaling mechanism which inhibit I(Ca-L) and, therefore, cardiac contractile function. We tested this idea by examining myocardial function in isolated hearts and Ca(2+) channel activity in isolated cardiac myocytes. Myocardial function was tested in Langendorff perfused hearts and I(Ca-L) were recorded in the whole-cell patch configuration by applying double pulses from a holding potential of -80 mV and then normalized to the peak amplitudes of control currents. 6-Aminonicotinamide, a competitive inhibitor of G6PD, increased pCO(2) and decreased pH. Additionally, 6-aminonicotinamide inhibited G6PD activity, reduced NADPH levels, attenuated peak I(Ca-L) amplitudes, and decreased left ventricular developed pressure and ±dp/dt. Finally, dialyzing NADPH into cells from the patch pipette solution attenuated the suppression of I(Ca-L) by 6-aminonicotinamide. Likewise, in G6PD-deficient mice, G6PD insufficiency in the heart decreased GSH-to-GSSG ratio, superoxide, cholesterol and acetyl CoA. In these mice, M-mode echocardiographic findings showed increased diastolic volume and end-diastolic diameter without changes in the fraction shortening. Taken together, these findings suggest that inhibiting G6PD activity and reducing NADPH levels alters metabolism and leads to inhibition of L-type Ca(2+) channel activity. Notably, this pathway may be involved in modulating myocardial contractility under physiological and pathophysiological conditions during which the pentose phosphate pathway-derived NADPH redox is modulated (e.g., ischemia-reperfusion and heart failure).

  4. Renal denervation attenuates NADPH oxidase-mediated oxidative stress and hypertension in rats with hydronephrosis.

    PubMed

    Peleli, Maria; Al-Mashhadi, Ammar; Yang, Ting; Larsson, Erik; Wåhlin, Nils; Jensen, Boye L; G Persson, A Erik; Carlström, Mattias

    2016-01-01

    Hydronephrosis is associated with the development of salt-sensitive hypertension. Studies have suggested that increased sympathetic nerve activity and oxidative stress play important roles in hypertension and the modulation of salt sensitivity. The present study primarily aimed to examine the role of renal sympathetic nerve activity in the development of hypertension in rats with hydronephrosis. In addition, we aimed to investigate if NADPH oxidase (NOX) function could be affected by renal denervation. Partial unilateral ureteral obstruction (PUUO) was created in 3-wk-old rats to induce hydronephrosis. Sham surgery or renal denervation was performed at the same time. Blood pressure was measured during normal, high-, and low-salt diets. The renal excretion pattern, NOX activity, and expression as well as components of the renin-angiotensin-aldosterone system were characterized after treatment with the normal salt diet. On the normal salt diet, rats in the PUUO group had elevated blood pressure compared with control rats (115 ± 3 vs. 87 ± 1 mmHg, P < 0.05) and displayed increased urine production and lower urine osmolality. The blood pressure change in response to salt loading (salt sensitivity) was more pronounced in the PUUO group compared with the control group (15 ± 2 vs. 5 ± 1 mmHg, P < 0.05). Renal denervation in PUUO rats attenuated both hypertension (97 ± 3 mmHg) and salt sensitivity (5 ± 1 mmHg, P < 0.05) and normalized the renal excretion pattern, whereas the degree of renal fibrosis and inflammation was not changed. NOX activity and expression as well as renin and ANG II type 1A receptor expression were increased in the renal cortex from PUUO rats and normalized by denervation. Plasma Na(+) and K(+) levels were elevated in PUUO rats and normalized after renal denervation. Finally, denervation in PUUO rats was also associated with reduced NOX expression, superoxide production, and fibrosis in the heart. In conclusion, renal denervation attenuates

  5. Depletion of NADP(H) due to CD38 activation triggers endothelial dysfunction in the postischemic heart.

    PubMed

    Reyes, Levy A; Boslett, James; Varadharaj, Saradhadevi; De Pascali, Francesco; Hemann, Craig; Druhan, Lawrence J; Ambrosio, Giuseppe; El-Mahdy, Mohamed; Zweier, Jay L

    2015-09-15

    In the postischemic heart, coronary vasodilation is impaired due to loss of endothelial nitric oxide synthase (eNOS) function. Although the eNOS cofactor tetrahydrobiopterin (BH4) is depleted, its repletion only partially restores eNOS-mediated coronary vasodilation, indicating that other critical factors trigger endothelial dysfunction. Therefore, studies were performed to characterize the unidentified factor(s) that trigger endothelial dysfunction in the postischemic heart. We observed that depletion of the eNOS substrate NADPH occurs in the postischemic heart with near total depletion from the endothelium, triggering impaired eNOS function and limiting BH4 rescue through NADPH-dependent salvage pathways. In isolated rat hearts subjected to 30 min of ischemia and reperfusion (I/R), depletion of the NADP(H) pool occurred and was most marked in the endothelium, with >85% depletion. Repletion of NADPH after I/R increased NOS-dependent coronary flow well above that with BH4 alone. With combined NADPH and BH4 repletion, full restoration of NOS-dependent coronary flow occurred. Profound endothelial NADPH depletion was identified to be due to marked activation of the NAD(P)ase-activity of CD38 and could be prevented by inhibition or specific knockdown of this protein. Depletion of the NADPH precursor, NADP(+), coincided with formation of 2'-phospho-ADP ribose, a CD38-derived signaling molecule. Inhibition of CD38 prevented NADP(H) depletion and preserved endothelium-dependent relaxation and NO generation with increased recovery of contractile function and decreased infarction in the postischemic heart. Thus, CD38 activation is an important cause of postischemic endothelial dysfunction and presents a novel therapeutic target for prevention of this dysfunction in unstable coronary syndromes.

  6. Protein-bound NAD(P)H Lifetime is Sensitive to Multiple Fates of Glucose Carbon.

    PubMed

    Sharick, Joe T; Favreau, Peter F; Gillette, Amani A; Sdao, Sophia M; Merrins, Matthew J; Skala, Melissa C

    2018-04-03

    While NAD(P)H fluorescence lifetime imaging (FLIM) can detect changes in flux through the TCA cycle and electron transport chain (ETC), it remains unclear whether NAD(P)H FLIM is sensitive to other potential fates of glucose. Glucose carbon can be diverted from mitochondria by the pentose phosphate pathway (via glucose 6-phosphate dehydrogenase, G6PDH), lactate production (via lactate dehydrogenase, LDH), and rejection of carbon from the TCA cycle (via pyruvate dehydrogenase kinase, PDK), all of which can be upregulated in cancer cells. Here, we demonstrate that multiphoton NAD(P)H FLIM can be used to quantify the relative concentrations of recombinant LDH and malate dehydrogenase (MDH) in solution. In multiple epithelial cell lines, NAD(P)H FLIM was also sensitive to inhibition of LDH and PDK, as well as the directionality of LDH in cells forced to use pyruvate versus lactate as fuel sources. Among the parameters measurable by FLIM, only the lifetime of protein-bound NAD(P)H (τ 2 ) was sensitive to these changes, in contrast to the optical redox ratio, mean NAD(P)H lifetime, free NAD(P)H lifetime, or the relative amount of free and protein-bound NAD(P)H. NAD(P)H τ 2 offers the ability to non-invasively quantify diversions of carbon away from the TCA cycle/ETC, which may support mechanisms of drug resistance.

  7. Lipid-free apolipoprotein A-I and discoidal reconstituted high-density lipoproteins differentially inhibit glucose-induced oxidative stress in human macrophages.

    PubMed

    Tabet, Fatiha; Lambert, Gilles; Cuesta Torres, Luisa F; Hou, Liming; Sotirchos, Irene; Touyz, Rhian M; Jenkins, Alicia J; Barter, Philip J; Rye, Kerry-Anne

    2011-05-01

    The goal of this study was to investigate the mechanisms by which apolipoprotein (apo) A-I, in the lipid-free form or as a constituent of discoidal reconstituted high-density lipoproteins ([A-I]rHDL), inhibits high-glucose-induced redox signaling in human monocyte-derived macrophages (HMDM). HMDM were incubated under normal (5.8 mmol/L) or high-glucose (25 mmol/L) conditions with native high-density lipoproteins (HDL) lipid-free apoA-I from normal subjects and from subjects with type 2 diabetes (T2D) or (A-I)rHDL. Superoxide (O2-) production was measured using dihydroethidium fluorescence. NADPH oxidase activity was assessed using lucigenin-derived chemiluminescence and a cyotochrome c assay. p47phox translocation to the plasma membrane, Nox2, superoxide dismutase 1 (SOD1), and SOD2 mRNA and protein levels were determined by real-time polymerase chain reaction and Western blotting. Native HDL induced a time-dependent inhibition of O2- generation in HMDM incubated with 25 mmol/L glucose. Lipid-free apoA-I and (A-I)rHDL increased SOD1 and SOD2 levels and attenuated 25 mmol/L glucose-mediated increases in cellular O2-, NADPH oxidase activity, p47 translocation, and Nox2 expression. Lipid-free apoA-I mediated its effects on Nox2, SOD1, and SOD2 via ABCA1. (A-I)rHDL-mediated effects were via ABCG1 and scavenger receptor BI. Lipid-free apoA-I from subjects with T2D inhibited reactive oxygen species generation less efficiently than normal apoA-I. Native HDL, lipid-free apoA-I and (A-I)rHDL inhibit high-glucose-induced redox signaling in HMDM. The antioxidant properties of apoA-I are attenuated in T2D.

  8. Interactions of Monoamine Oxidases with the Antiepileptic Drug Zonisamide: Specificity of Inhibition and Structure of the Human Monoamine oxidase B Complex

    PubMed Central

    Binda, Claudia; Aldeco, Milagros; Mattevi, Andrea; Edmondson, Dale E.

    2010-01-01

    The binding of zonisamide to purified, recombinant monoamine oxidases (MAOs) has been investigated. It is a competitive inhibitor of human MAO B (Ki = 3.1 ± 0.3 μM), of rat MAO B (Ki = 2.9 ± 0.5 μM), and of zebrafish MAO (Ki = 30.8 ± 5.3 μM). No inhibition is observed with purified human or rat MAO A. The 1.8 Å structure of the MAO B complex demonstrates that it binds within the substrate cavity. PMID:21175212

  9. Structure and function of NADPH-cytochrome P450 reductase and nitric oxide synthase reductase domain

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

    Iyanagi, Takashi

    2005-12-09

    NADPH-cytochrome P450 reductase (CPR) and the nitric oxide synthase (NOS) reductase domains are members of the FAD-FMN family of proteins. The FAD accepts two reducing equivalents from NADPH (dehydrogenase flavin) and FMN acts as a one-electron carrier (flavodoxin-type flavin) for the transfer from NADPH to the heme protein, in which the FMNH {sup {center_dot}}/FMNH{sub 2} couple donates electrons to cytochrome P450 at constant oxidation-reduction potential. Although the interflavin electron transfer between FAD and FMN is not strictly regulated in CPR, electron transfer is activated in neuronal NOS reductase domain upon binding calmodulin (CaM), in which the CaM-bound activated form canmore » function by a similar mechanism to that of CPR. The oxygenated form and spin state of substrate-bound cytochrome P450 in perfused rat liver are also discussed in terms of stepwise one-electron transfer from CPR. This review provides a historical perspective of the microsomal mixed-function oxidases including CPR and P450. In addition, a new model for the redox-linked conformational changes during the catalytic cycle for both CPR and NOS reductase domain is also discussed.« less

  10. The inhibition of monoamine oxidase by phenformin and pentamidine.

    PubMed

    Barkhuizen, M; Petzer, A; Petzer, J P

    2014-09-01

    A computational study has suggested that phenformin, an oral hypoglycaemic drug, may bind to the active sites of the monoamine oxidase (MAO) A and B enzymes. The present study therefore investigates the MAO inhibitory properties of phenformin. Pentamidine, a structurally related diamidine compound, has previously been reported to be a MAO inhibitor and was included in this study as a reference compound. Using recombinant human MAO-A and MAO-B, this study finds that phenformin acts as a moderately potent MAO-A selective inhibitor with an IC50 value of 41 µM. Pentamidine, on the other hand, potently inhibits both MAO-A and MAO-B with IC50 values of 0.61 μM and 0.22 μM, respectively. An examination of the recoveries of the enzymatic activities after dilution and dialysis of the enzyme-inhibitor complexes shows that both compounds interact reversibly with the MAO enzymes. A kinetic analysis suggests that pentamidine acts as a competitive inhibitor with estimated Ki values of 0.41 μM and 0.22 μM for the inhibition of MAO-A and MAO-B, respectively. Phenformin also exhibited a competitive mode of MAO-A inhibition with an estimated Ki value of 65 µM. This study concludes that biguanide and amidine functional groups are most likely important structural features for the inhibition of the MAOs by phenformin and pentamidine, and compounds containing these and closely related functional groups should be considered as potential MAO inhibitors. Furthermore, the biguanide and amidine functional groups may act as useful moieties in the future design of MAO inhibitors. © Georg Thieme Verlag KG Stuttgart · New York.

  11. Differential dose- and time-dependent effects of molindone on dopamine neurons of rat brain: mediation by irreversible inhibition of monoamine oxidase.

    PubMed

    Meller, E; Friedman, E

    1982-03-01

    The effects of molindone (2.5, 10 and 40 mg/kg) on striatal tyrosine hydroxylase activity and dopamine (DA), 3,4-dihydroxyphenylacetic acid and homovanillic acid levels were measured as a function of time (0-72 hr). Whereas a dose of 2.5 mg/kg produced effects typical of DA receptor blockade (activation of synaptosomal tyrosine hydroxylase, increased DA metabolite levels and unchanged DA levels), a dose of 40 mg/kg produced opposite effects (decreased tyrosine hydroxylase activity and metabolite concentrations and elevated DA levels). A dose of 10 mg/kg elicited intermediate effects. The atypical effects of both higher doses were long-lasting (less than 72 hr). Molindone at doses of 10 or 40 mg/kg, but nor 2.5 mg/kg, selectively, irreversibly and dose-dependently inhibited type A monoamine oxidase. This inhibition appeared to be due to a metabolite, inasmuch as the drug itself inhibited monoamine oxidase (reversibly) only at high concentrations (less than or equal to 10(-4) M). The heretofore unsuspected inhibition of monoamine oxidase by molindone provided a consistent mechanistic interpretation of the differential dose- and time-dependent effects of the drug on dopaminergic neuronal activity. This mechanism may also serve to explain the reported efficacy of molindone in animal tests for antidepressant activity as well as its inability to produce increased DA receptor binding after chronic treatment.

  12. NADPH-dependent coenzyme Q reductase is the main enzyme responsible for the reduction of non-mitochondrial CoQ in cells.

    PubMed

    Takahashi, Takayuki; Okuno, Masaaki; Okamoto, Tadashi; Kishi, Takeo

    2008-01-01

    We purified an NADPH-dependent coenzyme Q reductase (NADPH-CoQ reductase) in rat liver cytosol and compared its enzymatic properties with those of the other CoQ10 reductases such as NADPH: quinone acceptor oxidoreductase 1 (NQO1), lipoamide dehydrogenase, thioredoxine reductase and glutathione reductase. NADPH-CoQ reductase was the only enzyme that preferred NADPH to NADH as an electron donor and was also different from the other CoQ10 reductases in the sensitivities to its inhibitors and stimulators. Especially, Zn2+ was the most powerful inhibitor for NADPH-CoQ reductase, but CoQ10 reduction by the other CoQ10 reductases could not be inhibited by Zn2+. Furthermore, the reduction of the CoQ9 incorporated into HeLa cells was also inhibited by Zn2+ in the presence of pyrithione, a zinc ionophore. Moreover, NQO1 gene silencing in HeLa cells by transfection of a small interfering RNA resulted in lowering of both the NQO1 protein level and the NQO1 activity by about 75%. However, this transfection did not affect the NADPH-CoQ reductase activity and the reduction of CoQ9 incorporated into the cells. These results suggest that the NADPH-CoQ reductase located in cytosol may be the main enzyme responsible for the reduction of non-mitochondrial CoQ in cells.

  13. Selective inhibition of extracellular oxidants liberated from human neutrophils--A new mechanism potentially involved in the anti-inflammatory activity of hydroxychloroquine.

    PubMed

    Jančinová, Viera; Pažoureková, Silvia; Lucová, Marianna; Perečko, Tomáš; Mihalová, Danica; Bauerová, Katarína; Nosáľ, Radomír; Drábiková, Katarína

    2015-09-01

    Hydroxychloroquine is used in the therapy of rheumatoid arthritis or lupus erythematosus. Although these diseases are often accompanied by activation of neutrophils, there are still few data relating to the impact of hydroxychloroquine on these cells. We investigated the effect of orally administered hydroxychloroquine on neutrophil oxidative burst in rats with adjuvant arthritis. In human neutrophils, extra- and intracellular formation of oxidants, mobilisation of intracellular calcium and the phosphorylation of proteins regulating NADPH oxidase assembly were analysed. Administration of hydroxychloroquine decreased the concentration of oxidants in blood of arthritic rats. The inhibition was comparable with the reference drug methotrexate, yet it was not accompanied by a reduction in neutrophil count. When both drugs were co-applied, the effect became more pronounced. In isolated human neutrophils, treatment with hydroxychloroquine resulted in reduced mobilisation of intracellular calcium, diminished concentration of external oxidants and in decreased phosphorylation of Ca(2+)-dependent protein kinase C isoforms PKCα and PKCβII, which regulate activation of NADPH oxidase on plasma membrane. On the other hand, no reduction was observed in intracellular oxidants or in the phosphorylation of p40(phox) and PKCδ, two proteins directing the oxidase assembly to intracellular membranes. Hydroxychloroquine reduced neutrophil-derived oxidants potentially involved in tissue damage and protected those capable to suppress inflammation. The observed effects may represent a new mechanism involved in the anti-inflammatory activity of this drug. Copyright © 2015 Elsevier B.V. All rights reserved.

  14. Structural analysis of NADPH depleted bovine liver catalase and its inhibitor complexes

    PubMed Central

    Sugadev, Ragumani; Ponnuswamy, M.N.; Sekar, K.

    2011-01-01

    To study the functional role of NADPH during mammalian catalase inhibition, the X-ray crystal structures of NADPH-depleted bovine liver catalase and its inhibitor complexes, cyanide and azide, determined at 2.8Å resolution. From the complex structures it is observed that subunits with and without an inhibitor/catalytic water molecule are linked by N-terminal domain swapping. Comparing mammalian- and fungal- catalases, we speculate that NADPH-depleted mammalian catalases may function as a domain-swapped dimer of dimers, especially during inactivation by inhibitors like cyanide and azide. We further speculate that in mammalian catalases the N-terminal hinge-loop region and α-helix is the structural element that senses NADPH binding. Although the above arguments are speculative and need further verification, as a whole our studies have opened up a new possibility, viz. that mammalian catalase acts as a domain-swapped dimer of dimers, especially during inhibitor binding. To generalize this concept to the formation of the inactive state in mammalian catalases in the absence of tightly bound NADPH molecules needs further exploration. The present study adds one more intriguing fact to the existing mysteries of mammalian catalases. PMID:21968615

  15. Adipocyte-specific deficiency of NADPH oxidase 4 delays the onset of insulin resistance and attenuates adipose tissue inflammation in obesity

    PubMed Central

    Den Hartigh, Laura J.; Omer, Mohamed; Goodspeed, Leela; Wang, Shari; Wietecha, Tomasz; O’Brien, Kevin D.; Han, Chang Yeop

    2017-01-01

    Objective Obesity is associated with insulin resistance and adipose tissue inflammation. Reactive oxygen species (ROS) increase in adipose tissue during the development of obesity. We previously showed that in response to excess nutrients like glucose and palmitate, adipocytes generated ROS via NADPH oxidase (NOX) 4, the major adipocyte isoform, instead of using mitochondrial oxidation. However, the role of NOX4-derived ROS in the development of whole body insulin resistance, adipocyte inflammation, and recruitment of macrophages to adipose tissue during the development of obesity is unknown. Approach and Results In this study, control C57BL/6 mice and mice in which NOX4 has been deleted specifically in adipocytes were fed a high fat, high sucrose (HFHS) diet. During the development of obesity in control mice, adipocyte NOX4 and PPP activity were transiently increased. Primary adipocytes differentiated form mice with adipocytes deficient in NOX4 showed resistance against high glucose or palmitate-induced adipocyte inflammation. Mice with adipocytes deficient in NOX4 showed a delayed onset of insulin resistance during the development of obesity, with an initial reduction in adipose tissue inflammation that normalized with prolonged HFHS feeding. Conclusions These findings imply that NOX4-derived ROS may play a role in the onset of insulin resistance and adipose tissue inflammation. As such, therapeutics targeting NOX4-mediated ROS production could be effective in preventing obesity-associated conditions such as insulin resistance. PMID:28062496

  16. Adipocyte-Specific Deficiency of NADPH Oxidase 4 Delays the Onset of Insulin Resistance and Attenuates Adipose Tissue Inflammation in Obesity.

    PubMed

    Den Hartigh, Laura J; Omer, Mohamed; Goodspeed, Leela; Wang, Shari; Wietecha, Tomasz; O'Brien, Kevin D; Han, Chang Yeop

    2017-03-01

    Obesity is associated with insulin resistance and adipose tissue inflammation. Reactive oxygen species (ROS) increase in adipose tissue during the development of obesity. We previously showed that in response to excess nutrients like glucose and palmitate, adipocytes generated ROS via NADPH oxidase (NOX) 4, the major adipocyte isoform, instead of using mitochondrial oxidation. However, the role of NOX4-derived ROS in the development of whole body insulin resistance, adipocyte inflammation, and recruitment of macrophages to adipose tissue during the development of obesity is unknown. In this study, control C57BL/6 mice and mice in which NOX4 has been deleted specifically in adipocytes were fed a high-fat, high-sucrose diet. During the development of obesity in control mice, adipocyte NOX4 and pentose phosphate pathway activity were transiently increased. Primary adipocytes differentiated from mice with adipocytes deficient in NOX4 showed resistance against high glucose or palmitate-induced adipocyte inflammation. Mice with adipocytes deficient in NOX4 showed a delayed onset of insulin resistance during the development of obesity, with an initial reduction in adipose tissue inflammation that normalized with prolonged high-fat, high-sucrose feeding. These findings imply that NOX4-derived ROS may play a role in the onset of insulin resistance and adipose tissue inflammation. As such, therapeutics targeting NOX4-mediated ROS production could be effective in preventing obesity-associated conditions, such as insulin resistance. © 2016 American Heart Association, Inc.

  17. Roothairless5, which functions in maize (Zea mays L.) root hair initiation and elongation encodes a monocot-specific NADPH oxidase.

    PubMed

    Nestler, Josefine; Liu, Sanzhen; Wen, Tsui-Jung; Paschold, Anja; Marcon, Caroline; Tang, Ho Man; Li, Delin; Li, Li; Meeley, Robert B; Sakai, Hajime; Bruce, Wesley; Schnable, Patrick S; Hochholdinger, Frank

    2014-09-01

    Root hairs are instrumental for nutrient uptake in monocot cereals. The maize (Zea mays L.) roothairless5 (rth5) mutant displays defects in root hair initiation and elongation manifested by a reduced density and length of root hairs. Map-based cloning revealed that the rth5 gene encodes a monocot-specific NADPH oxidase. RNA-Seq, in situ hybridization and qRT-PCR experiments demonstrated that the rth5 gene displays preferential expression in root hairs but also accumulates to low levels in other tissues. Immunolocalization detected RTH5 proteins in the epidermis of the elongation and differentiation zone of primary roots. Because superoxide and hydrogen peroxide levels are reduced in the tips of growing rth5 mutant root hairs as compared with wild-type, and Reactive oxygen species (ROS) is known to be involved in tip growth, we hypothesize that the RTH5 protein is responsible for establishing the high levels of ROS in the tips of growing root hairs required for elongation. Consistent with this hypothesis, a comparative RNA-Seq analysis of 6-day-old rth5 versus wild-type primary roots revealed significant over-representation of only two gene ontology (GO) classes related to the biological functions (i.e. oxidation/reduction and carbohydrate metabolism) among 893 differentially expressed genes (FDR <5%). Within these two classes the subgroups 'response to oxidative stress' and 'cellulose biosynthesis' were most prominently represented. © 2014 The Authors The Plant Journal © 2014 John Wiley & Sons Ltd.

  18. Inhibition of xanthine oxidase reduces oxidative stress and improves skeletal muscle function in response to electrically stimulated isometric contractions in aged mice

    PubMed Central

    Ryan, Michael J.; Jackson, Janna R.; Hao, Yanlei; Leonard, Stephen S.; Alway, Stephen E.

    2012-01-01

    Oxidative stress is a putative factor responsible for reducing function and increasing apoptotic signaling in skeletal muscle with aging. This study examined the contribution and functional significance of the xanthine oxidase enzyme as a potential source of oxidant production in aged skeletal muscle during repetitive in situ electrically stimulated isometric contractions. Xanthine oxidase activity was inhibited in young adult and aged mice via a subcutaneously placed time release (2.5 mg/day) allopurinol pellet, 7 days prior to the start of in situ electrically stimulated isometric contractions. Gastrocnemius muscles were electrically activated with 20 maximal contractions for three consecutive days. Xanthine oxidase activity was 65% greater in the gastrocnemius muscle of aged mice compared to young mice. Xanthine oxidase activity also increased after in situ electrically stimulated isometric contractions in muscles from both young (33%) and aged (28%) mice, relative to contralateral non-contracted muscles. Allopurinol attenuated the exercise-induced increase in oxidative stress, but it did not affect the elevated basal levels of oxidative stress that was associated with aging. In addition, inhibition of xanthine oxidase activity decreased caspase 3 activity, but it had no effect on other markers of mitochondrial associated apoptosis. Our results show that compared to control conditions, suppression of xanthine oxidase activity by allopurinol reduced xanthine oxidase activity, H2O2 levels, lipid peroxidation and caspase-3 activity, prevented the in situ electrically stimulated isometric contraction-induced loss of glutathione, prevented the increase of catalase and copper-zinc superoxide dismutase activities, and increased maximal isometric force in the plantar flexor muscles of aged mice after repetitive electrically evoked contractions. PMID:21530649

  19. Eugenol and its structural analogs inhibit monoamine oxidase A and exhibit antidepressant-like activity.

    PubMed

    Tao, Guoxin; Irie, Yoshifumi; Li, Dian-Jun; Keung, Wing Ming

    2005-08-01

    Eugenol (1) is an active principle of Rhizoma acori graminei, a medicinal herb used in Asia for the treatment of symptoms reminiscent of Alzheimer's disease (AD). It has been shown to protect neuronal cells from the cytotoxic effect of amyloid beta peptides (Abetas) in cell cultures and exhibit antidepressant-like activity in mice. Results from this study show that eugenol inhibits monoamine oxidase A (MAOA) preferentially with a K(i)=26 microM. It also inhibits MAOB but at much higher concentrations (K(i)=211 microM). In both cases, inhibition is competitive with respect to the monoamine substrate. Survey of compounds structurally related to eugenol has identified a few that inhibit MAOs more potently. Structure activity relationship reveals structural features important for MAOA and MAOB inhibition. Molecular docking experiments were performed to help explain the SAR outcomes. Four of these compounds, two (1, 24) inhibiting MAOA selectively and the other two (19, 21) inhibiting neither MAOA nor MAOB, were tested for antidepressant-like activity using the forced swim test in mice. Results suggest a potential link between the antidepressant activity of eugenol and its MAOA inhibitory activity.

  20. A ROS-Assisted Calcium Wave Dependent on the AtRBOHD NADPH Oxidase and TPC1 Cation Channel Propagates the Systemic Response to Salt Stress.

    PubMed

    Evans, Matthew J; Choi, Won-Gyu; Gilroy, Simon; Morris, Richard J

    2016-07-01

    Plants exhibit rapid, systemic signaling systems that allow them to coordinate physiological and developmental responses throughout the plant body, even to highly localized and quickly changing environmental stresses. The propagation of these signals is thought to include processes ranging from electrical and hydraulic networks to waves of reactive oxygen species (ROS) and cytoplasmic Ca(2+) traveling throughout the plant. For the Ca(2+) wave system, the involvement of the vacuolar ion channel TWO PORE CHANNEL1 (TPC1) has been reported. However, the precise role of this channel and the mechanism of cell-to-cell propagation of the wave have remained largely undefined. Here, we use the fire-diffuse-fire model to analyze the behavior of a Ca(2+) wave originating from Ca(2+) release involving the TPC1 channel in Arabidopsis (Arabidopsis thaliana). We conclude that a Ca(2+) diffusion-dominated calcium-induced calcium-release mechanism is insufficient to explain the observed wave transmission speeds. The addition of a ROS-triggered element, however, is able to quantitatively reproduce the observed transmission characteristics. The treatment of roots with the ROS scavenger ascorbate and the NADPH oxidase inhibitor diphenyliodonium and analysis of Ca(2+) wave propagation in the Arabidopsis respiratory burst oxidase homolog D (AtrbohD) knockout background all led to reductions in Ca(2+) wave transmission speeds consistent with this model. Furthermore, imaging of extracellular ROS production revealed a systemic spread of ROS release that is dependent on both AtRBOHD and TPC1 These results suggest that, in the root, plant systemic signaling is supported by a ROS-assisted calcium-induced calcium-release mechanism intimately involving ROS production by AtRBOHD and Ca(2+) release dependent on the vacuolar channel TPC1. © 2016 American Society of Plant Biologists. All Rights Reserved.

  1. A pathogenesis assay using Saccharomyces cerevisiae and Caenorhabditis elegans reveals novel roles for yeast AP-1, Yap1, and host dual oxidase BLI-3 in fungal pathogenesis.

    PubMed

    Jain, Charu; Yun, Meijiang; Politz, Samuel M; Rao, Reeta Prusty

    2009-08-01

    Treatment of systemic fungal infections is difficult because of the limited number of antimycotic drugs available. Thus, there is an immediate need for simple and innovative systems to assay the contribution of individual genes to fungal pathogenesis. We have developed a pathogenesis assay using Caenorhabditis elegans, an established model host, with Saccharomyces cerevisiae as the invading fungus. We have found that yeast infects nematodes, causing disease and death. Our data indicate that the host produces reactive oxygen species (ROS) in response to fungal infection. Yeast mutants sod1Delta and yap1Delta, which cannot withstand ROS, fail to cause disease, except in bli-3 worms, which carry a mutation in a dual oxidase gene. Chemical inhibition of the NADPH oxidase activity abolishes ROS production in worms exposed to yeast. This pathogenesis assay is useful for conducting systematic, whole-genome screens to identify fungal virulence factors as alternative targets for drug development and exploration of host responses to fungal infections.

  2. Mechanistic insights into the inhibition of quercetin on xanthine oxidase.

    PubMed

    Zhang, Cen; Wang, Rui; Zhang, Guowen; Gong, Deming

    2018-06-01

    Quercetin, one of the most abundant flavonoid in the daily diet, was found to reversibly inhibit the generation of uric acid and superoxide radicals (O 2 - )catalyzed by xanthine oxidase (XOD) in a mixed-type manner with IC 50 values of (2.74±0.04)×10 -6 and (2.90±0.03)×10 -6 molL -1 , respectively, and the inhibition of quercetin on O 2 - generation may be ascribed to the reduced form of XOD by a ping-pong mechanism. XOD had one high affinity binding site for quercetin with a binding constant of 4.28×10 4 Lmol -1 at 298K, and the binding process was predominately driven by van der Waals forces and hydrogen bonds on account of the negative enthalpy and entropy changes. Moreover, molecular docking confirmed that the binding site for quercetin located in the isoalloxazine ring of the flavin adenine dinucleotide (FAD) domain of XOD, then the diffusion of O 2 - out of the FAD site was blocked in favor of another electron transferred from FADH 2 to O 2 - to form hydrogen peroxide (H 2 O 2 ). This study may clarify the role of quercetin on inhibiting XOD catalysis and provide a potential nutritional supplement for preventing gout and peroxidative damage. Copyright © 2018 Elsevier B.V. All rights reserved.

  3. Silica particles cause NADPH oxidase–independent ROS generation and transient phagolysosomal leakage

    PubMed Central

    Joshi, Gaurav N.; Goetjen, Alexandra M.; Knecht, David A.

    2015-01-01

    Chronic inhalation of silica particles causes lung fibrosis and silicosis. Silica taken up by alveolar macrophages causes phagolysosomal membrane damage and leakage of lysosomal material into the cytoplasm to initiate apoptosis. We investigated the role of reactive oxygen species (ROS) in this membrane damage by studying the spatiotemporal generation of ROS. In macrophages, ROS generated by NADPH oxidase 2 (NOX2) was detected in phagolysosomes containing either silica particles or nontoxic latex particles. ROS was only detected in the cytoplasm of cells treated with silica and appeared in parallel with an increase in phagosomal ROS, as well as several hours later associated with mitochondrial production of ROS late in apoptosis. Pharmacological inhibition of NOX activity did not prevent silica-induced phagolysosomal leakage but delayed it. In Cos7 cells, which do not express NOX2, ROS was detected in silica-containing phagolysosomes that leaked. ROS was not detected in phagolysosomes containing latex particles. Leakage of silica-containing phagolysosomes in both cell types was transient, and after resealing of the membrane, endolysosomal fusion continued. These results demonstrate that silica particles can generate phagosomal ROS independent of NOX activity, and we propose that this silica-generated ROS can cause phagolysosomal leakage to initiate apoptosis. PMID:26202463

  4. Coupling Drosophila melanogaster Cryptochrome Light Activation and Oxidation of the Kvβ Subunit Hyperkinetic NADPH Cofactor.

    PubMed

    Hong, Gongyi; Pachter, Ruth; Ritz, Thorsten

    2018-06-28

    Motivated by the observations on the involvement of light-induced processes in the Drosophila melanogaster cryptochrome (DmCry) in regulation of the neuronal firing rate, which is achieved by a redox-state change of its voltage-dependent K + channel Kvβ subunit hyperkinetic (Hk) reduced nicotinamide adenine dinucleotide phosphate (NADPH) cofactor, we propose in this work two hypothetical pathways that may potentially enable such coupling. In the first pathway, triggered by blue-light-induced formation of a radical pair [FAD •- TRP •+ ] in DmCry, the hole (TRP •+ ) may hop to Hk, for example, through a tryptophan chain and oxidize NADPH, possibly leading to inhibition of the N-terminus inactivation in the K + channel. In a second possible pathway, DmCry's FAD •- is reoxidized by molecular oxygen, producing H 2 O 2 , which then diffuses to Hk and oxidizes NADPH. In this work, by applying a combination of quantum and empirical-based methods for free-energy calculations, we find that the oxidation of NADPH by TRP •+ or H 2 O 2 and the reoxidation of FAD •- by O 2 are thermodynamically feasible. Our results may have an implication in identifying a magnetic sensing signal transduction pathway, specifically upon Drosophila's Hk NADPH cofactor oxidation, with a subsequent inhibition of the K + channel N-terminus inactivation gate, permitting K + flux.

  5. α4-Integrin Mediates Neutrophil-Induced Free Radical Injury to Cardiac Myocytes

    PubMed Central

    Poon, Betty Y.; Ward, Christopher A.; Cooper, Conan B.; Giles, Wayne R.; Burns, Alan R.; Kubes, Paul

    2001-01-01

    Previous work has demonstrated that circulating neutrophils (polymorphonuclear leukocytes [PMNs]) adhere to cardiac myocytes via β2-integrins and cause cellular injury via the nicotinamide adenine dinucleotide phosphate (NADPH) oxidase enzyme system. Since PMNs induced to leave the vasculature (emigrated PMNs) express the α4-integrin, we asked whether (a) these PMNs also induce myocyte injury via NADPH oxidase; (b) β2-integrins (CD18) still signal oxidant production, or if this process is now coupled to the α4-integrin; and (c) dysfunction is superoxide dependent within the myocyte or at the myocyte–PMN interface. Emigrated PMNs exposed to cardiac myocytes quickly induced significant changes in myocyte function. Myocyte shortening was decreased by 30–50% and rates of contraction and relaxation were reduced by 30% within the first 10 min. Both α4-integrin antibody (Ab)-treated PMNs and NADPH oxidase–deficient PMNs were unable to reduce myocyte shortening. An increased level of oxidative stress was detected in myocytes within 5 min of PMN adhesion. Addition of an anti–α4-integrin Ab, but not an anti-CD18 Ab, prevented oxidant production, suggesting that in emigrated PMNs the NADPH oxidase system is uncoupled from CD18 and can be activated via the α4-integrin. Addition of exogenous superoxide dismutase (SOD) inhibited all parameters of dysfunction measured, whereas overexpression of intracellular SOD within the myocytes did not inhibit the oxidative stress or the myocyte dysfunction caused by the emigrated PMNs. These findings demonstrate that profound molecular changes occur within PMNs as they emigrate, such that CD18 and associated intracellular signaling pathways leading to oxidant production are uncoupled and newly expressed α4-integrin functions as the ligand that signals oxidant production. The results also provide pathological relevance as the emigrated PMNs have the capacity to injure cardiac myocytes through the α4-integrin–coupled NADPH

  6. Alzheimer's disease: a gas model. The NADPH oxidase-Nitric Oxide system as an antibubble biomachinery.

    PubMed

    Denis, Pierre A

    2013-12-01

    Alzheimer's disease (AD) is a neurodegenerative disease of unknown origin. The pathological lesions that define AD would be linked to the insidious accumulation of nitrogen, having invaded the brain interstitial fluid (ISF) from the blood via the physiological cycling pool of vascular glucose transporters (GLUT-1). According to this hypothesis, the nitrogen nanobubbles, being chemically inert and actually indestructible for human beings, can not escape from the ISF anymore. They would exert a huge and deleterious pressure against cellular components, especially in microglia and in astrocytes. They could enhance the existing cell oxygen anisotropy, which might enhance the natural bubble nucleation of O2-2O2 in cells or in mitochondria. Indeed, with the help of a new symbolic representation for gas nuclei in chemical reactions, the NADPH oxidase-NO system is identified for the first time, as an antibubble biomachinery, able to break O2-2O2 bubbles up as it releases superoxide O2-. Superoxide is considered as a quantum bubble, which collapses through the reactivity of the gaseous NO radical. Their combination in soluble peroxinitrite provides the change from one state of matter to another, avoiding any risk of a bubble enlargement, and finally avoiding the risk of enzyme crowding or of a bulk pressure variation. However, a bubble is expected to entrap Nitric Oxide (NO), which leads theoretically to a decrease in its bioavailability, and is expected to trigger a guanylyl-cyclase-mediated inflammatory cascade, that could explain the inflammation in AD. In vitro, any increase in the hydrostatic pressure has already been linked to the microtubule disorganization. The amyloid deposits, also known as senile plaques, would behave as a sponge toward ISF nitrogen; Aβ is considered as a foam-stabilizing agent. By taking the shape of cerebral amyloid angiopathy, the amyloid could confine the nitrogen leak from the blood, and progressively insulate the Blood-Brain Barrier

  7. Fructose suppresses uric acid excretion to the intestinal lumen as a result of the induction of oxidative stress by NADPH oxidase activation.

    PubMed

    Kaneko, Chihiro; Ogura, Jiro; Sasaki, Shunichi; Okamoto, Keisuke; Kobayashi, Masaki; Kuwayama, Kaori; Narumi, Katsuya; Iseki, Ken

    2017-03-01

    A high intake of fructose increases the risk for hyperuricemia. It has been reported that long-term fructose consumption suppressed renal uric acid excretion and increased serum uric acid level. However, the effect of single administration of fructose on excretion of uric acid has not been clarified. We used male Wistar rats, which were orally administered fructose (5g/kg). Those rats were used in each experiment at 12h after administration. Single administration of fructose suppressed the function of ileal uric acid excretion and had no effect on the function of renal uric acid excretion. Breast cancer resistance protein (BCRP) predominantly contributes to intestinal excretion of uric acid as an active homodimer. Single administration of fructose decreased BCRP homodimer level in the ileum. Moreover, diphenyleneiodonium (DPI), an inhibitor of nicotinamide adenine dinucleotide phosphate (NADPH) oxidase (Nox), recovered the suppression of the function of ileal uric acid excretion and the Bcrp homodimer level in the ileum of rats that received single administration of fructose. Single administration of fructose decreases in BCRP homodimer level, resulting in the suppression the function of ileal uric acid excretion. The suppression of the function of ileal uric acid excretion by single administration of fructose is caused by the activation of Nox. The results of our study provide a new insight into the mechanism of fructose-induced hyperuricemia. Copyright © 2016 Elsevier B.V. All rights reserved.

  8. Inhibition of S-adenosylmethionine decarboxylase and diamine oxidase activities by analogues of methylglyoxal bis(guanylhydrazone) and their cellular uptake during lymphocyte activation.

    PubMed Central

    Jänne, J; Morris, D R

    1984-01-01

    Several congeners of methylglyoxal bis(guanylhydrazone) were tested for their ability to inhibit eukaryotic putrescine-activated S-adenosylmethionine decarboxylase (EC 4.1.1.50) and intestinal diamine oxidase (EC 1.4.3.6). All the compounds tested, namely methylglyoxal bis(guanylhydrazone), ethylglyoxal bis(guanylhydrazone), dimethylglyoxal bis(guanylhydrazone) and the di-N"-methyl derivative of methylglyoxal bis(guanylhydrazone), were strong inhibitors of both yeast and mouse liver adenosylmethionine decarboxylase activity in vitro. The enzyme from both sources was most powerfully inhibited by ethylglyoxal bis(guanylhydrazone). All the diguanidines likewise inhibited diamine oxidase activity in vitro. The maximum intracellular concentrations of the ethyl and dimethylated analogues achieved in activated lymphocytes were only about one-fifth of that of the parent compound. However, both derivatives appeared to utilize the polyamine-carrier system, as indicated by competition experiments with spermidine. PMID:6426466

  9. Inhibition of S-adenosylmethionine decarboxylase and diamine oxidase activities by analogues of methylglyoxal bis(guanylhydrazone) and their cellular uptake during lymphocyte activation.

    PubMed

    Jänne, J; Morris, D R

    1984-03-15

    Several congeners of methylglyoxal bis(guanylhydrazone) were tested for their ability to inhibit eukaryotic putrescine-activated S-adenosylmethionine decarboxylase (EC 4.1.1.50) and intestinal diamine oxidase (EC 1.4.3.6). All the compounds tested, namely methylglyoxal bis(guanylhydrazone), ethylglyoxal bis(guanylhydrazone), dimethylglyoxal bis(guanylhydrazone) and the di-N"-methyl derivative of methylglyoxal bis(guanylhydrazone), were strong inhibitors of both yeast and mouse liver adenosylmethionine decarboxylase activity in vitro. The enzyme from both sources was most powerfully inhibited by ethylglyoxal bis(guanylhydrazone). All the diguanidines likewise inhibited diamine oxidase activity in vitro. The maximum intracellular concentrations of the ethyl and dimethylated analogues achieved in activated lymphocytes were only about one-fifth of that of the parent compound. However, both derivatives appeared to utilize the polyamine-carrier system, as indicated by competition experiments with spermidine.

  10. Inhibition of NF-κB activity in the hypothalamic paraventricular nucleus attenuates hypertension and cardiac hypertrophy by modulating cytokines and attenuating oxidative stress

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

    Yu, Xiao-Jing; Zhang, Dong-Mei; Jia, Lin-Lin

    We hypothesized that chronic inhibition of NF-κB activity in the hypothalamic paraventricular nucleus (PVN) delays the progression of hypertension and attenuates cardiac hypertrophy by up-regulating anti-inflammatory cytokines, reducing pro-inflammatory cytokines (PICs), attenuating nuclear factor-κB (NF-κB) p65 and NAD(P)H oxidase in the PVN of young spontaneously hypertensive rats (SHR). Young normotensive Wistar–Kyoto (WKY) and SHR rats received bilateral PVN infusions with NF–κB inhibitor pyrrolidine dithiocarbamate (PDTC) or vehicle for 4 weeks. SHR rats had higher mean arterial pressure and cardiac hypertrophy as indicated by increased whole heart weight/body weight ratio, whole heart weight/tibia length ratio, left ventricular weight/tibia length ratio, cardiomyocytemore » diameters of the left cardiac ventricle, and mRNA expressions of cardiac atrial natriuretic peptide (ANP) and beta-myosin heavy chain (β-MHC). These SHR rats had higher PVN levels of proinflammatory cytokines (PICs), reactive oxygen species (ROS), the chemokine monocyte chemoattractant protein-1 (MCP-1), NAD(P)H oxidase activity, mRNA expression of NOX-2 and NOX-4, and lower PVN IL-10, and higher plasma levels of PICs and NE, and lower plasma IL-10. PVN infusion of NF-κB inhibitor PDTC attenuated all these changes. These findings suggest that NF-κB activation in the PVN increases sympathoexcitation and hypertensive response, which are associated with the increases of PICs and oxidative stress in the PVN; PVN inhibition of NF-κB activity attenuates PICs and oxidative stress in the PVN, thereby attenuates hypertension and cardiac hypertrophy. - Highlights: • Spontaneously hypertensive rats exhibit neurohormonal excitation in the PVN. • PVN inhibition of NF-κB attenuates hypertension-induced cardiac hypertrophy. • PVN inhibition of NF-κB attenuates hypertension-induced neurohormonal excitation. • PVN inhibition of NF-κB attenuates hypertension-induced imbalance of

  11. Cross talk between MMP2-Spm-Cer-S1P and ERK1/2 in proliferation of pulmonary artery smooth muscle cells under angiotensin II stimulation.

    PubMed

    Chowdhury, Animesh; Sarkar, Jaganmay; Pramanik, Pijush Kanti; Chakraborti, Tapati; Chakraborti, Sajal

    2016-08-01

    The aim of the present study is to establish the mechanism associated with the proliferation of PASMCs under ANG II stimulation. The results showed that treatment of PASMCs with ANG II induces an increase in cell proliferation and 100 nM was the optimum concentration for maximum increase in proliferation of the cells. Pretreatment of the cells with AT1, but not AT2, receptor antagonist inhibited ANG II induced cell proliferation. Pretreatment with pharmacological and genetic inhibitors of sphingomyelinase (SMase) and sphingosine kinase (SPHK) prevented ANG II-induced cell proliferation. ANG II has also been shown to induce SMase activity, SPHK phosphorylation and S1P production. In addition, ANG II caused an increase in proMMP-2 expression and activation, ERK1/2 phosphorylation and NADPH oxidase activation. Upon inhibition of MMP-2, SMase activity and S1P level were curbed leading to inhibition of cell proliferation. SPHK was phosphorylated by ERK1/2 during ET-1 stimulation of the cells. ANG II-induced ERK1/2 phosphorylation and proMMP-2 expression and activation in the cells were abrogated upon inhibition of NADPH oxidase activity. Overall, NADPH oxidase plays an important role in proMMP-2 expression and activation and that MMP-2 mediated SMC proliferation occurs through the involvement of Spm-Cer-S1P signaling axis under ANG II stimulation of PASMCs. Copyright © 2016 Elsevier Inc. All rights reserved.

  12. 15-Deoxy-∆12,14-PGJ 2, by activating peroxisome proliferator-activated receptor-gamma, suppresses p22phox transcription to protect brain endothelial cells against hypoxia-induced apoptosis.

    PubMed

    Wu, Jui-Sheng; Tsai, Hsin-Da; Huang, Chien-Yu; Chen, Jin-Jer; Lin, Teng-Nan

    2014-08-01

    15-Deoxy-∆(12,14)-PGJ(2) (15d-PGJ(2)) and thiazolidinedione attenuate reactive oxygen species (ROS) production via a peroxisome proliferator-activated receptor-gamma (PPAR-γ)-dependent pathway. Nonetheless, how PPAR-γ mediates ROS production to ameliorate ischemic brain injury is not clear. Recent studies indicated that nicotinamide adenine dinucleotide phosphate (NADPH) oxidase is the major source of ROS in the vascular system. In the present study, we used an in vitro oxygen-glucose deprivation and reoxygenation (hypoxia reoxygenation [HR]) paradigm to study whether PPAR-γ interacts with NADPH oxidase, thereby regulating ROS formation in cerebral endothelial cells (CECs). With pharmacological (PPAR-γ antagonist GW9662), loss-of-function (PPAR-γ siRNA), and gain-of-function (Ad-PPAR-γ) approaches, we first demonstrated that 15d-PGJ(2) protected HR-treated CECs against ROS-induced apoptosis in a PPAR-γ-dependent manner. Results of promoter and subcellular localization analyses further revealed that 15d-PGJ(2), by activating PPAR-γ, blocked HR-induced NF-κB nuclear translocation, which led to inhibited transcription of the NADPH oxidase subunit p22phox. In summary, we report a novel transrepression mechanism whereby PPAR-γ downregulates hypoxia-activated p22phox transcription and the subsequent NADPH oxidase activation, ROS formation, and CEC apoptosis.

  13. Elevated concentrations of nonesterified fatty acids increase monocyte expression of CD11b and adhesion to endothelial cells.

    PubMed

    Zhang, Wei-Yang; Schwartz, Eric; Wang, Yingjie; Attrep, Jeanne; Li, Zhi; Reaven, Peter

    2006-03-01

    Monocyte proinflammatory activity has been demonstrated in obesity, insulin resistance, and type 2 diabetes, metabolic conditions that are frequently associated with elevated levels of nonesterified fatty acids (NEFA). We therefore tested the hypothesis that NEFA may induce monocyte inflammation. Monocytes exposed to NEFA for 2 days demonstrated a dose-related increase in intracellular reactive oxygen species (ROS) formation and adhesion to endothelial cells. All of these effects were inhibited by the coaddition of antioxidants such as glutathione or butylated hydroxytoluene, by inhibition of ROS generation by NADPH oxidase inhibitors, and by inhibition of protein kinase C, a recognized stimulator of NAPDH oxidase. Monocytes exposed to NEFA also demonstrated a significant increase in CD11b message expression. Stimulation of monocyte adhesion to endothelial cells by NEFA was inhibited by addition of neutralizing antibodies to either CD11b or CD18. Finally, surface expression of CD11b increased significantly on monocytes as measured by flow cytometry, after their incubation with NEFA. These studies indicate that elevated concentrations of NEFA may enhance integrin facilitated monocyte adhesion to endothelial cells and these effects appear mediated, in part, through activation of NADPH oxidase and oxidative stress.

  14. Colorimetric assay of heparin in plasma based on the inhibition of oxidase-like activity of citrate-capped platinum nanoparticles.

    PubMed

    You, Jyun-Guo; Liu, Yao-Wen; Lu, Chi-Yu; Tseng, Wei-Lung; Yu, Cheng-Ju

    2017-06-15

    We report citrate-capped platinum nanoparticles (Pt NPs) as oxidase mimetics for effectively catalyzing the oxidation of 3,3',5,5'-tetramethylbenzidine (TMB), 2,2'-azino-bis (3-ethylbenzthiazoline-6-sulfonic acid), dopamine, and methylene blue in the presence of O 2 . To confirm oxidase-like activity of citrate-capped Pt NPs, their activity toward oxygen reduction reaction was studied using cyclic voltammetry and rotating ring-disk electrode method. The results obtained showed that Pt NP NPs can catalyze the oxidation of organic substrates to the colored product and the reduction of oxygen to water through a four-electron exchange process. Because the aggregation of Pt NPs can inhibit their oxidase-like activity and protamine can recognize heparin, we prepared the protamine-modified Pt NPs through direct adsorption on the surface of citrate-capped Pt NPs. The electrostatic attraction between heparin and protamine-stabilized Pt NPs induced nanoparticle aggregation, inhibiting their catalytic activity. Therefore, the lowest detectable heparin concentrations through UV-vis absorption and by the naked eye were estimated to be 0.3 and 60nM, respectively. Moreover, the proposed system enabled the determination of the therapeutic heparin concentration in a single drop of blood. Copyright © 2016 Elsevier B.V. All rights reserved.

  15. Ascorbate protects endothelial barrier function during septic insult: Role of protein phosphatase type 2A.

    PubMed

    Han, Min; Pendem, Suresh; Teh, Suet Ling; Sukumaran, Dinesh K; Wu, Feng; Wilson, John X

    2010-01-01

    Endothelial barrier dysfunction contributes to morbidity in sepsis. We tested the hypothesis that raising the intracellular ascorbate concentration protects the endothelial barrier from septic insult by inhibiting protein phosphatase type 2A. Monolayer cultures of microvascular endothelial cells were incubated with ascorbate, dehydroascorbic acid (DHAA), the NADPH oxidase inhibitors apocynin and diphenyliodonium, or the PP2A inhibitor okadaic acid and then were exposed to septic insult (lipopolysaccharide and interferon-gamma). Under standard culture conditions that depleted intracellular ascorbate, septic insult stimulated oxidant production and PP2A activity, dephosphorylated phosphoserine and phosphothreonine residues in the tight junction-associated protein occludin, decreased the abundance of occludin at cell borders, and increased monolayer permeability to albumin. NADPH oxidase inhibitors prevented PP2A activation and monolayer leak, showing that these changes required reactive oxygen species. Okadaic acid, at a concentration that inhibited PP2A activity and monolayer leak, prevented occludin dephosphorylation and redistribution, implicating PP2A in the response of occludin to septic insult. Incubation with ascorbate or DHAA raised intracellular ascorbate concentrations and mitigated the effects of septic insult. In conclusion, ascorbate acts within microvascular endothelial cells to inhibit septic stimulation of oxidant production by NADPH oxidase and thereby prevents PP2A activation, PP2A-dependent dephosphorylation and redistribution of occludin, and disruption of the endothelial barrier. Copyright 2009 Elsevier Inc. All rights reserved.

  16. AO 1535 inhibits O2- production by human macrophages.

    PubMed

    Spampinato, G; Messina, L; Malaguarnera, L; Arcidiacono, A; Giuffrida, M A; Guarniera, E; Geremia, E; Rastrelli, A; Messina, A

    1992-01-01

    AO 1535 is a semisynthetic monoglycosylceramide derived from O-glycosilated sphingosine, with a chemical structure similar to the glycolipids present in many mammalian tissues. In the epidermis monoglycosylceramides contribute to consolidate the structure of cutaneous layers. It has been recently shown that sphingosine and its derivatives are potent inhibitors of Protein kinase C, and block the 'respiratory burst' of phagocitic cells. In macrophages, like in neutrophils, the reactive oxygen intermediates are produced by a membrane associated enzymatic complex, NADPH-oxidase, which is activated by Protein kinase C. This study demonstrates that AO 1535 is able to inhibit the production of reactive oxygen intermediates in human monocytes and macrophages stimulated by phorbol ester and chemotactic tetrapeptide, suggesting a potential clinical application of AO 1535 in the treatment of inflammatory dermatoses.

  17. Mitochondrial Impairment May Increase Cellular NAD(P)H: Resazurin Oxidoreductase Activity, Perturbing the NAD(P)H-Based Viability Assays.

    PubMed

    Aleshin, Vasily A; Artiukhov, Artem V; Oppermann, Henry; Kazantsev, Alexey V; Lukashev, Nikolay V; Bunik, Victoria I

    2015-08-21

    Cellular NAD(P)H-dependent oxidoreductase activity with artificial dyes (NAD(P)H-OR) is an indicator of viability, as the cellular redox state is important for biosynthesis and antioxidant defense. However, high NAD(P)H due to impaired mitochondrial oxidation, known as reductive stress, should increase NAD(P)H-OR yet perturb viability. To better understand this complex behavior, we assayed NAD(P)H-OR with resazurin (Alamar Blue) in glioblastoma cell lines U87 and T98G, treated with inhibitors of central metabolism, oxythiamin, and phosphonate analogs of 2-oxo acids. Targeting the thiamin diphosphate (ThDP)-dependent enzymes, the inhibitors are known to decrease the NAD(P)H production in the pentose phosphate shuttle and/or upon mitochondrial oxidation of 2-oxo acids. Nevertheless, the inhibitors elevated NAD(P)H-OR with resazurin in a time- and concentration-dependent manner, suggesting impaired NAD(P)H oxidation rather than increased viability. In particular, inhibition of the ThDP-dependent enzymes affects metabolism of malate, which mediates mitochondrial oxidation of cytosolic NAD(P)H. We showed that oxythiamin not only inhibited mitochondrial 2-oxo acid dehydrogenases, but also induced cell-specific changes in glutamate and malate dehydrogenases and/or malic enzyme. As a result, inhibition of the 2-oxo acid dehydrogenases compromises mitochondrial metabolism, with the dysregulated electron fluxes leading to increases in cellular NAD(P)H-OR. Perturbed mitochondrial oxidation of NAD(P)H may thus complicate the NAD(P)H-based viability assay.

  18. Crosstalk of mitochondria with NADPH oxidase via reactive oxygen and nitrogen species signalling and its role for vascular function

    PubMed Central

    Di Lisa, Fabio; Oelze, Matthias; Kröller‐Schön, Swenja; Steven, Sebastian; Schulz, Eberhard; Münzel, Thomas

    2016-01-01

    Abstract Cardiovascular diseases are associated with and/or caused by oxidative stress. This concept has been proven by using the approach of genetic deletion of reactive species producing (pro‐oxidant) enzymes as well as by the overexpression of reactive species detoxifying (antioxidant) enzymes leading to a marked reduction of reactive oxygen and nitrogen species (RONS) and in parallel to an amelioration of the severity of diseases. Likewise, the development and progression of cardiovascular diseases is aggravated by overexpression of RONS producing enzymes as well as deletion of antioxidant RONS detoxifying enzymes. Thus, the consequences of the interaction (redox crosstalk) of superoxide/hydrogen peroxide produced by mitochondria with other ROS producing enzymes such as NADPH oxidases (Nox) are of outstanding importance and will be discussed including the consequences for endothelial nitric oxide synthase (eNOS) uncoupling as well as the redox regulation of the vascular function/tone in general (soluble guanylyl cyclase, endothelin‐1, prostanoid synthesis). Pathways and potential mechanisms leading to this crosstalk will be analysed in detail and highlighted by selected examples from the current literature including hypoxia, angiotensin II‐induced hypertension, nitrate tolerance, aging and others. The general concept of redox‐based activation of RONS sources via “kindling radicals” and enzyme‐specific “redox switches” will be discussed providing evidence that mitochondria represent key players and amplifiers of the burden of oxidative stress. Linked Articles This article is part of a themed section on Redox Biology and Oxidative Stress in Health and Disease. To view the other articles in this section visit http://onlinelibrary.wiley.com/doi/10.1111/bph.v174.12/issuetoc PMID:26660451

  19. Effects of losartan on hepatic expression of nonphagocytic NADPH oxidase and fibrogenic genes in patients with chronic hepatitis C.

    PubMed

    Colmenero, Jordi; Bataller, Ramón; Sancho-Bru, Pau; Domínguez, Marlene; Moreno, Montserrat; Forns, Xavier; Bruguera, Miquel; Arroyo, Vicente; Brenner, David A; Ginès, Pere

    2009-10-01

    Angiotensin II promotes liver fibrogenesis by stimulating nonphagocytic NADPH oxidase (NOX)-induced oxidative stress. Angiotensin II type 1 (AT1) receptor blockers attenuate experimental liver fibrosis, yet their effects in human liver fibrosis are unknown. We investigated the effects of losartan on hepatic expression of fibrogenic, inflammatory, and NOX genes in patients with chronic hepatitis C (CHC). Fourteen patients with CHC and liver fibrosis received oral losartan (50 mg/day) for 18 mo. Liver biopsies were performed at baseline and after treatment. The degree of inflammation and fibrosis was evaluated by histological analysis (METAVIR). Collagen content was measured by morphometric quantification of Sirius red staining. Overall collagen content and fibrosis stage remained stable in the whole series, yet the fibrosis stage decreased in seven patients. Inflammatory activity improved in seven patients. The effect of losartan on hepatic expression of 31 profibrogenic and inflammatory genes and components of the NOX complex was assessed by quantitative PCR. Losartan treatment was associated with a significant decrease in the expression of several profibrogenic and NOX genes including procollagen alpha1(I) and alpha1(IV), urokinase-type plasminogen activator, metalloproteinase type 2, NOX activator 1 (NOXA-1) and organizer 1 (NOXO-1), and Rac-1. Losartan was well tolerated in all patients and was effective in attenuating the activity of the systemic renin-angiotensin system. No effects on serum liver tests or viral load were observed. We conclude that prolonged administration of losartan, an oral AT1 receptor blocker, is associated with downregulation of NOX components and fibrogenic genes in patients with CHC. Controlled studies are warranted to assess the effect of AT1 receptor blockers in chronic liver injury.

  20. Phycocyanin and phycocyanobilin from Spirulina platensis protect against diabetic nephropathy by inhibiting oxidative stress.

    PubMed

    Zheng, Jing; Inoguchi, Toyoshi; Sasaki, Shuji; Maeda, Yasutaka; McCarty, Mark F; Fujii, Masakazu; Ikeda, Noriko; Kobayashi, Kunihisa; Sonoda, Noriyuki; Takayanagi, Ryoichi

    2013-01-15

    We and other investigators have reported that bilirubin and its precursor biliverdin may have beneficial effects on diabetic vascular complications, including nephropathy, via its antioxidant effects. Here, we investigated whether phycocyanin derived from Spirulina platensis, a blue-green algae, and its chromophore phycocyanobilin, which has a chemical structure similar to that of biliverdin, protect against oxidative stress and renal dysfunction in db/db mice, a rodent model for Type 2 diabetes. Oral administration of phycocyanin (300 mg/kg) for 10 wk protected against albuminuria and renal mesangial expansion in db/db mice, and normalized tumor growth factor-β and fibronectin expression. Phycocyanin also normalized urinary and renal oxidative stress markers and the expression of NAD(P)H oxidase components. Similar antioxidant effects were observed following oral administration of phycocyanobilin (15 mg/kg) for 2 wk. Phycocyanobilin, bilirubin, and biliverdin also inhibited NADPH dependent superoxide production in cultured renal mesangial cells. In conclusion, oral administration of phycocyanin and phycocyanobilin may offer a novel and feasible therapeutic approach for preventing diabetic nephropathy.

  1. Vascular lysyl oxidase over-expression alters extracellular matrix structure and induces oxidative stress.

    PubMed

    Varona, Saray; García-Redondo, Ana B; Martínez-González, Jose; Salaices, Mercedes; Briones, Ana M; Rodríguez, Cristina

    Lysyl oxidase (LOX) participates in the assembly of collagen and elastin fibres. The impact of vascular LOX over-expression on extracellular matrix (ECM) structure and its contribution to oxidative stress has been analysed. Studies were conducted on mice over-expressing LOX (Tg), specifically in smooth muscle cells (VSMC). Gene expression was assessed by real-time PCR analysis. Sirius Red staining, H 2 O 2 production and NADPH oxidase activity were analysed in different vascular beds. The size and number of fenestra of the internal elastic lamina were determined by confocal microscopy. LOX activity was up-regulated in VSMC of transgenic mice compared with cells from control animals. At the same time, transgenic cells deposited more organised elastin fibres and their supernatants induced a stronger collagen assembly in in vitro assays. Vascular collagen cross-linking was also higher in Tg mice, which showed a decrease in the size of fenestrae and an enhanced expression of Fibulin-5. Interestingly, higher H 2 O 2 production and NADPH oxidase activity was detected in the vascular wall from transgenic mice. The H 2 O 2 scavenger catalase attenuated the stronger deposition of mature elastin fibres induced by LOX transgenesis. LOX over-expression in VSMC was associated with a change in the structure of collagen and elastin fibres. LOX could constitute a novel source of oxidative stress that might participate in elastin changes and contribute to vascular remodelling. Copyright © 2017 Sociedad Española de Arteriosclerosis. Publicado por Elsevier España, S.L.U. All rights reserved.

  2. Monoamine oxidase B (MAO-B) inhibition by active principles from Uncaria rhynchophylla.

    PubMed

    Hou, Wen-Chi; Lin, Rong-Dih; Chen, Cheng-Tang; Lee, Mei-Hsien

    2005-08-22

    Attenuation of monoamine oxidase B (MAO-B) activity may provide protection against oxidative neurodegeneration. For this reason, inhibition of MAO-B activity is used as part of the treatment of Parkinson's and Alzheimer's patients. The hook of Uncaria rhynchophylla (Miq.) Jacks. (Rubiaceae) is a traditional Chinese herbal drug that is generally used to treat convulsive disorders. In this study, the fractionation and purification of Uncaria rhynchophylla extracts using a bioguided assay isolated two known compounds, (+)-catechin and (-)-epicatechin. The compounds inhibited MAO-B, as measured by an assay of rat brain MAO-B separated by electrophoresis on a 7.5% native polyacrylamide gel. The IC(50) values of (+)-catechin and (-)-epicatechin were 88.6 and 58.9 microM, respectively, and inhibition occurred in a dose-dependent manner, as measured by the fluorescence method. The Lineweaver-Burk plot revealed K(i) values for (+)-catechin and (-)-epicatechin of 74 and 21 microM, respectively. This suggests that these two compounds, isolated here for the first time from Uncaria rhynchophylla, might be able to protect against neurodegeneration in vitro, and, therefore, the molecular mechanism deserves further study. This finding may also increase interest in the health benefits of Uncaria rhynchophylla.

  3. Ethers and esters derived from apocynin avoid the interaction between p47phox and p22phox subunits of NADPH oxidase: evaluation in vitro and in silico.

    PubMed

    Macías-Pérez, Martha Edith; Martínez-Ramos, Federico; Padilla-Martínez, Itzia Irene; Correa-Basurto, José; Kispert, Lowell; Mendieta-Wejebe, Jessica Elena; Rosales-Hernández, Martha Cecilia

    2013-08-02

    NOX (NADPH oxidase) plays an important role during several pathologies because it produces the superoxide anion (O2•-), which reacts with NO (nitric oxide), diminishing its vasodilator effect. Although different isoforms of NOX are expressed in ECs (endothelial cells) of blood vessels, the NOX2 isoform has been considered the principal therapeutic target for vascular diseases because it can be up-regulated by inhibiting the interaction between its p47phox (cytosolic protein) and p22phox (transmembrane protein) subunits. In this research, two ethers, 4-(4-acetyl-2-methoxy-phenoxy)-acetic acid (1) and 4-(4-acetyl-2-methoxy-phenoxy)-butyric acid (2) and two esters, pentanedioic acid mono-(4-acetyl-2-methoxy-phenyl) ester (3) and heptanedioic acid mono-(4-acetyl-2-methoxy-phenyl) ester (4), which are apocynin derivatives were designed, synthesized and evaluated as NOX inhibitors by quantifying O2•- production using EPR (electron paramagnetic resonance) measurements. In addition, the antioxidant activity of apocynin and its derivatives were determined. A docking study was used to identify the interactions between the NOX2's p47phox subunit and apocynin or its derivatives. The results showed that all of the compounds exhibit inhibitory activity on NOX, being 4 the best derivative. However, neither apocynin nor its derivatives were free radical scavengers. On the other hand, the in silico studies demonstrated that the apocynin and its derivatives were recognized by the polybasic SH3A and SH3B domains, which are regions of p47phox that interact with p22phox. Therefore this experimental and theoretical study suggests that compound 4 could prevent the formation of the complex between p47phox and p22phox without needing to be activated by MPO (myeloperoxidase), this being an advantage over apocynin.

  4. Marked and variable inhibition by chemical fixation of cytochrome oxidase and succinate dehydrogenase in single motoneurons

    NASA Technical Reports Server (NTRS)

    Chalmers, G. R.; Edgerton, V. R.

    1989-01-01

    The effect of tissue fixation on succinate dehydrogenase and cytochrome oxidase activity in single motoneurons of the rat was demonstrated using a computer image processing system. Inhibition of enzyme activity by chemical fixation was variable, with some motoneurons being affected more than others. It was concluded that quantification of enzymatic activity in chemically fixed tissue provides an imprecise estimate of enzyme activities found in fresh-frozen tissues.

  5. Monoamine oxidase-B inhibition in the treatment of Parkinson's disease.

    PubMed

    Fernandez, Hubert H; Chen, Jack J

    2007-12-01

    Inhibitors of monoamine oxidase (MAO) with selectivity and specificity for MAO type B prolong the activity of both endogenously and exogenously derived dopamine, making them an option either as monotherapy in early Parkinson's disease or as adjunctive therapy in patients treated with levodopa who are experiencing motor complications. In addition to symptomatic benefits, experimental data suggest that MAO-B inhibitors may be neuroprotective through MAO-B inhibition and other mechanisms that have yet to be clearly defined. The two available MAO-B inhibitors approved for use in the United States, rasagiline and selegiline, each provide symptomatic relief as monotherapy and as adjunctive therapy, and have shown potential disease-modifying effects in experimental models and clinical studies. Selegiline in a conventional tablet formulation is less bioavailable than rasagiline, resulting in limited potency. It also has amphetamine metabolites that may produce adverse effects and interfere with any putative disease-modifying effects. The oral disintegrating tablet formulation of selegiline allows pregastric absorption, minimizing first-pass metabolism, thereby increasing selegiline bioavailability and reducing the concentration of amphetamine metabolites. Rasagiline, more potent than selegiline, exhibits disease-modifying effects in experimental models and lacks amphetamine metabolites. Both the symptomatic and potential disease-modifying effects of rasagiline are under investigation. A third agent with MAO-B inhibition properties, safinamide, is in phase III development. Although not yet approved, safinamide may offer the added advantage of combined MAO-B and dopamine reuptake inhibition.

  6. Indicaxanthin inhibits NADPH oxidase (NOX)-1 activation and NF-κB-dependent release of inflammatory mediators and prevents the increase of epithelial permeability in IL-1β-exposed Caco-2 cells.

    PubMed

    Tesoriere, L; Attanzio, A; Allegra, M; Gentile, C; Livrea, M A

    2014-02-01

    Dietary redox-active/antioxidant phytochemicals may help control or mitigate the inflammatory response in chronic inflammatory bowel disease (IBD). In the present study, the anti-inflammatory activity of indicaxanthin (Ind), a pigment from the edible fruit of cactus pear (Opuntia ficus-indica, L.), was shown in an IBD model consisting of a human intestinal epithelial cell line (Caco-2 cells) stimulated by IL-1β, a cytokine known to play a major role in the initiation and amplification of inflammatory activity in IBD. The exposure of Caco-2 cells to IL-1β brought about the activation of NADPH oxidase (NOX-1) and the generation of reactive oxygen species (ROS) to activate intracellular signalling leading to the activation of NF-κB, with the over-expression of inflammatory enzymes and release of pro-inflammatory mediators. The co-incubation of the cells with Ind, at a nutritionally relevant concentration (5-25 μM), and IL-1β prevented the release of the pro-inflammatory cytokines IL-6 and IL-8, PGE2 and NO, the formation of ROS and the loss of thiols in a dose-dependent manner. The co-incubation of the cells with Ind and IL-1β also prevented the IL-1β-induced increase of epithelial permeability. It was also shown that the activation of NOX-1 and NF-κB was prevented by Ind and the expression of COX-2 and inducible NO synthase was reduced. The uptake of Ind in Caco-2 cell monolayers appeared to be unaffected by the inflamed state of the cells. In conclusion, our findings suggest that the dietary pigment Ind may have the potential to modulate inflammatory processes at the intestinal level.

  7. SPERMINE OXIDASE: AN AMINE OXIDASE WITH SPECIFICITY FOR SPERMINE AND SPERMIDINE

    PubMed Central

    Hirsch, James G.

    1953-01-01

    Sheep serum and bovine serum contain an enzyme which brings about a rapid oxidative deamination of certain biological amines. This enzyme differs from previously described amine oxidases in several regards and especially in its substrate specificity. Studies thus far indicate that only spermine and the closely related compound spermidine serve as substrates for the enzyme in sheep serum. For this reason, the enzyme has been named spermine oxidase. Spermine oxidase is active in a variety of fluids of various ionic strength and buffer composition. The reaction takes place between pH 6.0 and pH 8.0 with an optimal rate in the vicinity of neutrality. Under certain conditions, the rate of oxygen consumption during the initial phase of the reaction is independent of the concentration of substrate. The diminution in rate observed during the latter phase of the enzymatic attack appears to be due to an alteration in the kinetics at low concentrations of substrate, or to competitive inhibition by a product of the reaction. Carbonyl reagents almost completely block the action of spermine oxidase, while certain amines and the cyanide ion bring about partial inhibition. Thiol reagents and sequestering compounds do not alter the course of the oxidative process. In the presence of low concentrations of mercuric chloride, the sheep serum-spermine system consumes approximately twice as much oxygen as controls containing no mercuric ion. The mechanism by which the mercuric ion stimulates additional oxygen uptake is obscure. PMID:13052805

  8. Time-dependent slowly-reversible inhibition of monoamine oxidase A by N-substituted 1,2,3,6-tetrahydropyridines.

    PubMed

    Wichitnithad, Wisut; O'Callaghan, James P; Miller, Diane B; Train, Brian C; Callery, Patrick S

    2011-12-15

    A novel class of N-substituted tetrahydropyridine derivatives was found to have multiple kinetic mechanisms of monoamine oxidase A inhibition. Eleven structurally similar tetrahydropyridine derivatives were synthesized and evaluated as inhibitors of MAO-A and MAO-B. The most potent MAO-A inhibitor in the series, 2,4-dichlorophenoxypropyl analog 12, displayed time-dependent mixed noncompetitive inhibition. The inhibition was reversed by dialysis, indicating reversible enzyme inhibition. Evidence that the slow-binding inhibition of MAO-A with 12 involves a covalent bond was gained from stabilizing a covalent reversible intermediate product by reduction with sodium borohydride. The reduced enzyme complex was not reversible by dialysis. The results are consistent with slowly reversible, mechanism-based inhibition. Two tetrahydropyridine analogs that selectively inhibited MAO-A were characterized by kinetic mechanisms differing from the kinetic mechanism of 12. As reversible inhibitors of MAO-A, tetrahydropyridine analogs are at low risk of having an adverse effect of tyramine-induced hypertension. Copyright © 2011 Elsevier Ltd. All rights reserved.

  9. Glucose-6-phosphate dehydrogenase, NADPH, and cell survival.

    PubMed

    Stanton, Robert C

    2012-05-01

    Glucose-6-phosphate dehydrogenase (G6PD) is the rate-limiting enzyme of the pentose phosphate pathway. Many scientists think that the roles and regulation of G6PD in physiology and pathophysiology have been well established as the enzyme was first identified 80 years ago. And that G6PD has been extensively studied especially with respect to G6PD deficiency and its association with hemolysis, and with respect to the role G6PD plays in lipid metabolism. But there has been a growing understanding of the central importance of G6PD to cellular physiology as it is a major source of NADPH that is required by many essential cellular systems including the antioxidant pathways, nitric oxide synthase, NADPH oxidase, cytochrome p450 system, and others. Indeed G6PD is essential for cell survival. It has also become evident that G6PD is highly regulated by many signals that affect transcription, post-translation, intracellular location, and interactions with other protein. Pathophysiologic roles for G6PD have also been identified in such disease processes as diabetes, aldosterone-induced endothelial dysfunction, cancer, and others. It is now clear that G6PD is under complex regulatory control and of central importance to many cellular processes. In this review the biochemistry, regulatory signals, physiologic roles, and pathophysiologic roles for G6PD that have been elucidated over the past 20 years are discussed. Copyright © 2012 Wiley Periodicals, Inc.

  10. A novel amperometric enzyme inhibition biosensor based on xanthine oxidase immobilised onto glassy carbon electrodes for bisphenol A determination.

    PubMed

    Ben Messaoud, Najib; Ghica, Mariana Emilia; Dridi, Cherif; Ben Ali, Mounir; Brett, Christopher M A

    2018-07-01

    A novel and simple biosensor for the determination of bisphenol A (BPA) based on xanthine oxidase (XOD) enzymatic inhibition has been developed. The biosensor was prepared from xanthine oxidase immobilised by crosslinking with glutaraldehyde, with hypoxanthine as enzyme substrate, and was successfully applied to the determination of BPA using fixed potential amperometry. Biosensor performance was optimised with respect to the applied potential, influence of pH of the electrolyte solution, XOD loading and the substrate concentration. The enzyme inhibition mechanism was evaluated from Cornish-Bowden plus Dixon plots and was found to be reversible and competitive with an apparent inhibition constant of 8.15 nM. Under optimised conditions, the determination of BPA can be achieved in the linear range up to 41 nM with a detection limit of 1.0 nM, which is equal to the lowest reported in the literature, with very good repeatability and reproducibility. The selectivity of the biosensor was evaluated by performing an interference study and found to be excellent; and stability was investigated. It was successfully applied to the detection of BPA in mineral water and in river water. Copyright © 2018 Elsevier B.V. All rights reserved.

  11. Hypoxia/oxidative stress alters the pharmacokinetics of CPU86017-RS through mitochondrial dysfunction and NADPH oxidase activation.

    PubMed

    Gao, Jie; Ding, Xuan-sheng; Zhang, Yu-mao; Dai, De-zai; Liu, Mei; Zhang, Can; Dai, Yin

    2013-12-01

    Hypoxia/oxidative stress can alter the pharmacokinetics (PK) of CPU86017-RS, a novel antiarrhythmic agent. The aim of this study was to investigate the mechanisms underlying the alteration of PK of CPU86017-RS by hypoxia/oxidative stress. Male SD rats exposed to normal or intermittent hypoxia (10% O2) were administered CPU86017-RS (20, 40 or 80 mg/kg, ig) for 8 consecutive days. The PK parameters of CPU86017-RS were examined on d 8. In a separate set of experiments, female SD rats were injected with isoproterenol (ISO) for 5 consecutive days to induce a stress-related status, then CPU86017-RS (80 mg/kg, ig) was administered, and the tissue distributions were examined. The levels of Mn-SOD (manganese containing superoxide dismutase), endoplasmic reticulum (ER) stress sensor proteins (ATF-6, activating transcription factor 6 and PERK, PRK-like ER kinase) and activation of NADPH oxidase (NOX) were detected with Western blotting. Rat liver microsomes were incubated under N2 for in vitro study. The Cmax, t1/2, MRT (mean residence time) and AUC (area under the curve) of CPU86017-RS were significantly increased in the hypoxic rats receiving the 3 different doses of CPU86017-RS. The hypoxia-induced alteration of PK was associated with significantly reduced Mn-SOD level, and increased ATF-6, PERK and NOX levels. In ISO-treated rats, the distributions of CPU86017-RS in plasma, heart, kidney, and liver were markedly increased, and NOX levels in heart, kidney, and liver were significantly upregulated. Co-administration of the NOX blocker apocynin eliminated the abnormalities in the PK and tissue distributions of CPU86017-RS induced by hypoxia/oxidative stress. The metabolism of CPU86017-RS in the N2-treated liver microsomes was significantly reduced, addition of N-acetylcysteine (NAC), but not vitamin C, effectively reversed this change. The altered PK and metabolism of CPU86017-RS induced by hypoxia/oxidative stress are produced by mitochondrial abnormalities, NOX activation

  12. Activation of the Small GTPase Rap1 Inhibits Choroidal Neovascularization by Regulating Cell Junctions and ROS Generation in Rats.

    PubMed

    Li, Jiajia; Zhang, Rong; Wang, Caixia; Wang, Xin; Xu, Man; Ma, Jingxue; Shang, Qingli

    2018-03-30

    Choroidal neovascularization (CNV) is a common vision-threatening complication associated with many  fundus diseases. The retinal pigment epithelial (RPE) cell junction barrier has critical functions in preventing CNV, and oxidative stress can cause compromise of barrier integrity and induce angiogenesis. Rap1, a small guanosine triphosphatase (GTPase), is involved in regulating endothelial and epithelial cell junctions. In this work, we explored the function and mechanism of Rap1 in CNV in vivo. A laser-induced rat CNV model was developed. Rap1 was activated through intravitreal injection of the Rap1 activator 8CPT-2'-O-Me-cAMP (8CPT). At 14 days after laser treatment, CNV size in RPE/choroid flat mounts was measured by fluorescein isothiocyanate-dextran staining. Expression of vascular endothelial growth factor (VEGF) and cell junction proteins in RPE/choroid tissues were analyzed by western blots and quantitative real-time PCR assays. Reactive oxygen species (ROS) in RPE cells were detectedbydichloro-dihydro-fluorescein diacetate assays. The antioxidant apocynin was intraperitoneally injected into rats. Activating Rap1 by 8CPT significantly reduced CNV size and VEGF expression in the rat CNV model. Rap1 activation enhanced protein and mRNA levels of ZO-1 and occludin, two tight junction proteins in the RPE barrier. In addition, reducing ROS generation by injection of apocynin, a NADPH oxidase inhibitor, inhibited CNV formation. Rap1 activation reduced ROS generation and expression of NADPH oxidase 4. Rap1 activation inhibits CNV through regulating barrier integrity and ROS generation of RPE in vivo, and selectively activating Rap1 may be a way to reduce vision loss from CNV.

  13. Role of endoplasmic reticulum stress in 12/15-lipoxygenase-induced retinal microvascular dysfunction in a mouse model of diabetic retinopathy.

    PubMed

    Elmasry, Khaled; Ibrahim, Ahmed S; Saleh, Heba; Elsherbiny, Nehal; Elshafey, Sally; Hussein, Khaled A; Al-Shabrawey, Mohamed

    2018-05-01

    Our earlier studies have established the role of 12/15-lipoxygenase (LO) in mediating the inflammatory reaction in diabetic retinopathy. However, the exact mechanism is still unclear. The goal of the current study was to identify the potential role of endoplasmic reticulum (ER) stress as a major cellular stress response in the 12/15-LO-induced retinal changes in diabetic retinopathy. We used in vivo and in vitro approaches. For in vivo studies, experimental diabetes was induced in wild-type (WT) mice and 12/15-Lo (also known as Alox15) knockout mice (12/15-Lo -/- ); ER stress was then evaluated after 12-14 weeks of diabetes. We also tested the effect of intravitreal injection of 12-hydroxyeicosatetraenoic acid (HETE) on retinal ER stress in WT mice and in mice lacking the catalytic subunit of NADPH oxidase, encoded by Nox2 (also known as Cybb) (Nox2 -/- mice). In vitro studies were performed using human retinal endothelial cells (HRECs) treated with 15-HETE (0.1 μmol/l) or vehicle, with or without ER stress or NADPH oxidase inhibitors. This was followed by evaluation of ER stress response, NADPH oxidase expression/activity and the levels of phosphorylated vascular endothelial growth factor receptor-2 (p-VEGFR2) by western blotting and immunoprecipitation assays. Moreover, real-time imaging of intracellular calcium (Ca 2+ ) release in HRECs treated with or without 15-HETE was performed using confocal microscopy. Deletion of 12/15-Lo significantly attenuated diabetes-induced ER stress in mouse retina. In vitro, 15-HETE upregulated ER stress markers such as phosphorylated RNA-dependent protein kinase-like ER-regulated kinase (p-PERK), activating transcription factor 6 (ATF6) and protein disulfide isomerase (PDI) in HRECs. Inhibition of ER stress reduced 15-HETE-induced-leucocyte adhesion, VEGFR2 phosphorylation and NADPH oxidase expression/activity. However, inhibition of NADPH oxidase or deletion of Nox2 had no effect on ER stress induced by the 12/15-LO

  14. Mitochondrial Impairment May Increase Cellular NAD(P)H: Resazurin Oxidoreductase Activity, Perturbing the NAD(P)H-Based Viability Assays

    PubMed Central

    Aleshin, Vasily A.; Artiukhov, Artem V.; Oppermann, Henry; Kazantsev, Alexey V.; Lukashev, Nikolay V.; Bunik, Victoria I.

    2015-01-01

    Cellular NAD(P)H-dependent oxidoreductase activity with artificial dyes (NAD(P)H-OR) is an indicator of viability, as the cellular redox state is important for biosynthesis and antioxidant defense. However, high NAD(P)H due to impaired mitochondrial oxidation, known as reductive stress, should increase NAD(P)H-OR yet perturb viability. To better understand this complex behavior, we assayed NAD(P)H-OR with resazurin (Alamar Blue) in glioblastoma cell lines U87 and T98G, treated with inhibitors of central metabolism, oxythiamin, and phosphonate analogs of 2-oxo acids. Targeting the thiamin diphosphate (ThDP)-dependent enzymes, the inhibitors are known to decrease the NAD(P)H production in the pentose phosphate shuttle and/or upon mitochondrial oxidation of 2-oxo acids. Nevertheless, the inhibitors elevated NAD(P)H-OR with resazurin in a time- and concentration-dependent manner, suggesting impaired NAD(P)H oxidation rather than increased viability. In particular, inhibition of the ThDP-dependent enzymes affects metabolism of malate, which mediates mitochondrial oxidation of cytosolic NAD(P)H. We showed that oxythiamin not only inhibited mitochondrial 2-oxo acid dehydrogenases, but also induced cell-specific changes in glutamate and malate dehydrogenases and/or malic enzyme. As a result, inhibition of the 2-oxo acid dehydrogenases compromises mitochondrial metabolism, with the dysregulated electron fluxes leading to increases in cellular NAD(P)H-OR. Perturbed mitochondrial oxidation of NAD(P)H may thus complicate the NAD(P)H-based viability assay. PMID:26308058

  15. Resveratrol prevents angiotensin II-induced hypertrophy of vascular smooth muscle cells through the transactivation of growth factor receptors.

    PubMed

    Hossain, Ekhtear; Anand-Srivastava, Madhu B

    2017-08-01

    We previously showed that augmented levels of endogenous angiotensin II (AngII) contribute to vascular smooth muscle cell (VSMC) hypertrophy through the transactivation of growth factor receptors in spontaneously hypertensive rats. Resveratrol (RV), a polyphenolic component of red wine, has also been shown to attenuate AngII-evoked VSMC hypertrophy; however, the molecular mechanism mediating this response is obscure. The present study was therefore undertaken to examine whether RV could prevent AngII-induced VSMC hypertrophy through the transactivation of growth factor receptor and associated signaling pathways. AngII treatment of VSMC enhanced the protein synthesis that was attenuated towards control levels by RV pretreatment as well as by the inhibitors of NADPH oxidase, c-Src, and growth factor receptors. Furthermore, RV pretreatment also inhibited enhanced levels of superoxide anion, NADPH oxidase activity, increased expression of NADPH oxidase subunits, and phosphorylation of c-Src, EGF-R, PDGE-R, ERK1/2, and AKT1/2. In conclusion, these results indicate that RV attenuates AngII-induced VSMC hypertrophy through the inhibition of enhanced oxidative stress and activation of c-Src, growth factor receptors, and MAPK/AKT signaling. We suggest that RV could be used as a therapeutic agent in the treatment of vascular complications associated with hypertension and hypertrophy.

  16. Inhibition of acetylcholinesterase and cytochrome oxidase activity in Fasciola gigantica cercaria by phytoconstituents.

    PubMed

    Sunita, Kumari; Habib, Maria; Kumar, P; Singh, Vinay Kumar; Husain, Syed Akhtar; Singh, D K

    2016-02-01

    Fasciolosis is an important cattle and human disease caused by Fasciola hepatica and Fasciola gigantica. One of the possible methods to control this problem is to interrupt the life cycle of Fasciola by killing its larva (redia and cercaria) in host snail. Molecular identification of cercaria larva of F. gigantica was done by comparing the nucleotide sequencing with adult F. gigantica. It was noted that nucleotide sequencing of cercaria larva and adult F. gigantica were 99% same. Every month during the year 2011-2012, in vivo treatment with 60% of 4 h LC50 of phyto cercaricides citral, ferulic acid, umbelliferone, azadirachtin and allicin caused significant inhibition of acetylcholinesterase (AChE) and cytochrome oxidase activity in the treated cercaria larva of F. gigantica. Whereas, activity of both enzymes were not significantly altered in the nervous tissues of vector snail Lymnaea acuminata exposed to same treatments. Maximum reduction in AChE (1.35% of control in month of June) and cytochrome oxidase (3.71% of control in the month of July) activity were noted in the cercaria exposed to 60% of 4 h LC50 of azadirachtin and allicin, respectively. Copyright © 2015 Elsevier B.V. All rights reserved.

  17. Contrasting Influence of NADPH and a NADPH-Regenerating System on the Metabolism of Carbonyl-Containing Compounds in Hepatic Microsomes

    EPA Science Inventory

    Carbonyl containing xenobiotics may be susceptible to NADPH-dependent cytochrome P450 (P450) and carbonyl-reduction reactions. In vitro hepatic microsome assays are routinely supplied NADPH either by direct addition of NADPH or via an NADPH-regenerating system (NRS). In contrast ...

  18. Effects of Monoamine Oxidase Inhibition on the Reinforcing Properties of Low-Dose Nicotine.

    PubMed

    Smith, Tracy T; Rupprecht, Laura E; Cwalina, Samantha N; Onimus, Matthew J; Murphy, Sharon E; Donny, Eric C; Sved, Alan F

    2016-08-01

    The Food and Drug Administration (FDA) has the authority to regulate cigarette smoke constituents, and a reduction in nicotine content might benefit public health by reducing the prevalence of smoking. Research suggests that cigarette smoke constituents that inhibit monoamine oxidase (MAO) may increase the reinforcing value of low doses of nicotine. The aim of the present experiments was to further characterize the impact of MAO inhibition on the primary reinforcing and reinforcement enhancing effects of nicotine in rats. In a series of experiments, rats responded for intravenous nicotine infusions or a moderately-reinforcing visual stimulus in daily 1-h sessions. Rats received pre-session injections of known MAO inhibitors. The results show that (1) tranylcypromine (TCP), a known MAO inhibitor, increases sensitivity to the primary reinforcing effects of nicotine, shifting the dose-response curve for nicotine to the left, (2) inhibition of MAO-A, but not MAO-B, increases low-dose nicotine self-administration, (3) partial MAO-A inhibition, to the degree observed in chronic cigarette smokers, also increases low-dose nicotine self-administration, and (4) TCP decreases the threshold nicotine dose required for reinforcement enhancement. The results of the present experiments suggest cigarette smoke constituents that inhibit MAO-A, in the range seen in chronic smokers, are likely to increase the primary reinforcing and reinforcement enhancing effects of low doses of nicotine. If the FDA reduces the nicotine content of cigarettes, then variability in constituents that inhibit MAO-A could impact smoking.

  19. Mechanism and characteristics of stimuli-dependent ROS generation in undifferentiated HL-60 cells.

    PubMed

    Muranaka, Shikibu; Fujita, Hirofumi; Fujiwara, Takuzo; Ogino, Tetsuya; Sato, Eisuke F; Akiyama, Jitsuo; Imada, Isuke; Inoue, Masayasu; Utsumi, Kozo

    2005-01-01

    It has been widely believed that undifferentiated human promyelocytic leukemia cells (HL-60) have no ability to generate reactive oxygen species (ROS) responding to stimuli. We report here that undifferentiated HL-60 cells possess NADPH oxidase and that generation of superoxide can be measured using a highly sensitive chemiluminescence dye, L-012. Five subunits of NADPH oxidase, namely, gp91(phox), p22(phox), p67(phox), p47(phox), and Rac 2, were detected in undifferentiated HL-60 cells by immunoblotting analysis. The contents of these NADPH oxidase components in the cells were increased with the differentiation induced by phorbol myristate acetate (PMA), except for p22(phox). Messenger RNAs of these subunits were also detected by the RT-PCR method, and their expressions increased except that of p22(phox) with the differentiation induced by PMA. Kinetic analysis using L-012 revealed that HL-60 cells generated substantial amounts of ROS by various stimulants, including formylmethionyl-leucyl-phenylalanine, PMA, myristic acid, and a Ca2+ ionophore, A23187. Both diphenyleneiodonium (an inhibitor of FAD-dependent oxidase) and apocynin (a specific inhibitor of NADPH oxidase) suppressed this stimuli-dependent ROS generation. Genistein, staurosporine, uric acid, and sodium azide inhibited the ROS generation in undifferentiated HL-60 cells in a similar way to that in undifferentiated neutrophils. These results suggested that the mechanism of ROS generation in undifferentiated HL-60 cells is the same as that in primed neutrophils.

  20. Fructose increases corticosterone production in association with NADPH metabolism alterations in rat epididymal white adipose tissue.

    PubMed

    Prince, Paula D; Santander, Yanina A; Gerez, Estefania M; Höcht, Christian; Polizio, Ariel H; Mayer, Marcos A; Taira, Carlos A; Fraga, Cesar G; Galleano, Monica; Carranza, Andrea

    2017-08-01

    Metabolic syndrome is an array of closely metabolic disorders that includes glucose intolerance/insulin resistance, central obesity, dyslipidemia, and hypertension. Fructose, a highly lipogenic sugar, has profound metabolic effects in adipose tissue, and has been associated with the etiopathology of many components of the metabolic syndrome. In adipocytes, the enzyme 11 β-HSD1 amplifies local glucocorticoid production, being a key player in the pathogenesis of central obesity and metabolic syndrome. 11 β-HSD1 reductase activity is dependent on NADPH, a cofactor generated by H6PD inside the endoplasmic reticulum. Our focus was to explore the effect of fructose overload on epididymal white adipose tissue (EWAT) machinery involved in glucocorticoid production and NADPH and oxidants metabolism. Male Sprague-Dawley rats fed with a fructose solution (10% (w/v) in tap water) during 9 weeks developed some characteristic features of metabolic syndrome, such as hypertriglyceridemia, and hypertension. In addition, high levels of plasma and EWAT corticosterone were detected. Activities and expressions of H6PD and 11 β-HSD1, NAPDH content, superoxide anion production, expression of NADPH oxidase 2 subunits, and indicators of oxidative metabolism were measured. Fructose overloaded rats showed an increased potential in oxidant production respect to control rats. In parallel, in EWAT from fructose overloaded rats we found higher expression/activity of H6PD and 11 β-HSD1, and NADPH/NADP + ratio. Our in vivo results support that fructose overload installs in EWAT conditions favoring glucocorticoid production through higher H6PD expression/activity supplying NADPH for enhanced 11 β-HSD1 expression/activity, becoming this tissue a potential extra-adrenal source of corticosterone under these experimental conditions. Copyright © 2017 Elsevier Inc. All rights reserved.

  1. NADPH oxidase 2-derived reactive oxygen species signal contributes to bradykinin-induced matrix metalloproteinase-9 expression and cell migration in brain astrocytes

    PubMed Central

    2012-01-01

    Background Matrix metalloproteinase-9 (MMP-9) plays a crucial role in pathological processes of brain inflammation, injury, and neurodegeneration. Moreover, bradykinin (BK) induces the expression of several inflammatory proteins in brain astrocytes. Recent studies have suggested that increased oxidative stress is implicated in the brain inflammation and injury. However, whether BK induced MMP-9 expression mediated through oxidative stress remains virtually unknown. Herein we investigated the role of redox signals in BK-induced MMP-9 expression in rat brain astrocytes (RBA-1 cells). Results In the study, we first demonstrated that reactive oxygen species (ROS) plays a crucial role in BK-induced MMP-9 expression in cultured brain astrocytes (in vitro) and animal brain tissue (in vivo) models. Next, BK-induced MMP-9 expression is mediated through a Ca2+-mediated PKC-α linking to p47phox/NADPH oxidase 2 (Nox2)/ROS signaling pathway. Nox2-dependent ROS generation led to activation and up-regulation of the downstream transcriptional factor AP-1 (i.e. c-Fos and c-Jun), which bound to MMP-9 promoter region, and thereby turned on transcription of MMP-9 gene. Functionally, BK-induced MMP-9 expression enhanced astrocytic migration. Conclusions These results demonstrated that in RBA-1 cells, activation of AP-1 (c-Fos/c-Jun) by the PKC-α-mediated Nox2/ROS signals is essential for up-regulation of MMP-9 and cell migration enhanced by BK. PMID:23176293

  2. Coadministration of VDR and RXR agonists synergistically alleviates atherosclerosis through inhibition of oxidative stress: An in vivo and in vitro study.

    PubMed

    Lin, L M; Peng, F; Liu, Y P; Chai, D J; Ning, R B; Xu, C S; Lin, J X

    2016-08-01

    Diabetes contributes to atherosclerosis partially through induction of oxidative stress. Both vitamin D receptor (VDR) and retinoid X receptor (RXR) agonists exhibit anti-atherogenic effects. We explored the effects of combination treatment with VDR and RXR agonists (represented by calcitriol and bexarotene, respectively) on atherosclerosis progression and the mechanisms involved, using a diabetes model of mice. The animals were intragastrically fed calcitriol (200 ng/kg, twice-a-week), bexarotene (10 mg/kg, once-daily) either alone or in combination for 12 weeks. VDR and RXR agonists delayed atherosclerosis progression independent of serum lipid and glucose levels, and significantly reduced the protein expression of nicotinamide adenine dinucleotide phosphate (NADPH) oxidase subunit gp91phox and nuclear factor-kappa B (NF-κB) subunit p65, as well as plasma biomarkers of oxidative stress and inflammation. Combination therapy alleviated atherosclerosis and inhibited indexes of oxidative stress and inflammation to a greater extent than either monotherapy. In the in vitro study, naturally occurring VDR ligand 1α,25-dihydroxyvitamin D3 (1,25[OH]2D3) and RXR ligand 9-cis retinoic acid (9-cis-RA), both significantly inhibited high-glucose-induced endothelial cell apoptosis. Co-administration of VDR and RXR ligands produced synergistic protection against endothelial apoptosis by antagonizing the protein kinase C /NADPH oxidase/reactive oxygen species pathway. The inhibitory effects of 9-cis-RA on oxidative stress was attenuated when VDR was downregulated by VDR siRNA; however, downregulation of RXR by RXR siRNA imposed no influence on the effects of 1,25(OH)2D3. Combination treatment with VDR and RXR agonists synergistically alleviated diabetic atherosclerosis through inhibition of oxidative stress, and the preventive effects of RXR agonist may partially depend on VDR activation. Copyright © 2016. Published by Elsevier Ireland Ltd.

  3. Purification of the Alpha Glycerophosphate Oxidase from African Trypanosomes

    DTIC Science & Technology

    1987-02-02

    oxidase (GPO). This enzyme has not been purified or characterize in detail. Inhibition of this enzyme coupled with inhibition of the anaerobic...more manageable afterwards and remained in the procedure although it only slightly increased the yield. The stability of the solubilized enzyme was...whether the detergent was added during the assay or in the solubilization procedure. However, the successful assay for the enzyme was ubiquinol oxidase

  4. Monoamine Oxidase-A Inhibition and Associated Antioxidant Activity in Plant Extracts with Potential Antidepressant Actions

    PubMed Central

    Guillén, Hugo

    2018-01-01

    Monoamine oxidase (MAO) catalyzes the oxidative deamination of amines and neurotransmitters and is involved in mood disorders, depression, oxidative stress, and adverse pharmacological reactions. This work studies the inhibition of human MAO-A by Hypericum perforatum, Peganum harmala, and Lepidium meyenii, which are reported to improve and affect mood and mental conditions. Subsequently, the antioxidant activity associated with the inhibition of MAO is determined in plant extracts for the first time. H. perforatum inhibited human MAO-A, and extracts from flowers gave the highest inhibition (IC50 of 63.6 μg/mL). Plant extracts were analyzed by HPLC-DAD-MS and contained pseudohypericin, hypericin, hyperforin, adhyperforin, hyperfirin, and flavonoids. Hyperforin did not inhibit human MAO-A and hypericin was a poor inhibitor of this isoenzyme. Quercetin and flavonoids significantly contributed to MAO-A inhibition. P. harmala seed extracts highly inhibited MAO-A (IC50 of 49.9 μg/L), being a thousand times more potent than H. perforatum extracts owing to its content of β-carboline alkaloids (harmaline and harmine). L. meyenii root (maca) extracts did not inhibit MAO-A. These plants may exert protective actions related to antioxidant effects. Results in this work show that P. harmala and H. perforatum extracts exhibit antioxidant activity associated with the inhibition of MAO (i.e., lower production of H2O2). PMID:29568754

  5. The monoamine oxidase inhibition properties of selected structural analogues of methylene blue.

    PubMed

    Delport, Anzelle; Harvey, Brian H; Petzer, Anél; Petzer, Jacobus P

    2017-06-15

    The thionine dye, methylene blue (MB), is a potent inhibitor of monoamine oxidase (MAO) A, a property that may, at least in part, mediate its antidepressant effects in humans and animals. The central inhibition of MAO-A by MB has also been linked to serotonin toxicity (ST) which may arise when MB is used in combination with serotonergic drugs. Structural analogues and the principal metabolite of MB, azure B, have also been reported to inhibit the MAO enzymes, with all compounds exhibiting specificity for the MAO-A isoform. To expand on the structure-activity relationships (SARs) of MAO inhibition by MB analogues, the present study investigates the human MAO inhibition properties of five MB analogues: neutral red, Nile blue, new methylene blue, cresyl violet and 1,9-dimethyl methylene blue. Similar to MB, these analogues also are specific MAO-A inhibitors with cresyl violet (IC 50 =0.0037μM), Nile blue (IC 50 =0.0077μM) and 1,9-dimethyl methylene blue (IC 50 =0.018μM) exhibiting higher potency inhibition compared to MB (IC 50 =0.07μM). Nile blue also represents a potent MAO-B inhibitor with an IC 50 value of 0.012μM. From the results it may be concluded that non-thionine MB analogues (e.g. cresyl violet and Nile blue) also may exhibit potent MAO inhibition, a property which should be considered when using these compounds in pharmacological studies. Benzophenoxazines such as cresyl violet and Nile blue are, similar to phenothiazines (e.g. MB), representative of high potency MAO-A inhibitors with a potential risk of ST. Copyright © 2017 Elsevier Inc. All rights reserved.

  6. Quantitative Protein Sulfenic Acid Analysis Identifies Platelet Releasate-Induced Activation of Integrin β2 on Monocytes via NADPH Oxidase.

    PubMed

    Li, Ru; Klockenbusch, Cordula; Lin, Liwen; Jiang, Honghui; Lin, Shujun; Kast, Juergen

    2016-12-02

    Physiological stimuli such as thrombin, or pathological stimuli such as lysophosphatidic acid (LPA), activate platelets. The activated platelets bind to monocytes through P-selectin-PSGL-1 interactions but also release the contents of their granules, commonly called "platelet releasate". It is known that monocytes in contact with platelet releasate produce reactive oxygen species (ROS). Reversible cysteine oxidation by ROS is considered to be a potential regulator of protein function. In a previous study, we used THP-1 monocytic cells exposed to LPA- or thrombin-induced platelet releasate and a modified biotin switch assay to unravel the biological processes that are influenced by reversible cysteine oxidation. To gain a better understanding of the redox regulation of monocytes in atherosclerosis, we have now altered the modified biotin switch to selectively quantify protein sulfenic acid, a subpopulation of reversible cysteine oxidation. Using arsenite as reducing agent in the modified biotin switch assay, we were able to quantify 1161 proteins, in which more than 100 sulfenic acid sites were identified. Bioinformatics analysis of the quantified sulfenic acid sites highlighted the relevant, previously missed biological process of monocyte transendothelial migration, which included integrin β 2 . Flow cytometry validated the activation of LFA-1 (α L β 2 ) and Mac-1 (α M β 2 ), two subfamilies of integrin β 2 complexes, on human primary monocytes following platelet releasate treatment. The activation of LFA-1 was mediated by ROS from NADPH oxidase (NOX) activation. Production of ROS and activation of LFA-1 in human primary monocytes were independent of P-selectin-PSGL-1 interaction. Our results proved the modified biotin switch assay to be a powerful tool with the ability to reveal new regulatory mechanisms and identify new therapeutic targets.

  7. Apocynin protects against ethanol-induced gastric ulcer in rats by attenuating the upregulation of NADPH oxidases 1 and 4.

    PubMed

    El-Naga, Reem N

    2015-12-05

    Gastric ulcer is a common gastrointestinal disorder affecting many people all over the world. Absolute ethanol (5 ml/kg) was used to induce gastric ulceration in rats. Apocynin (50 mg/kg) was given orally one hour before the administration of absolute ethanol. Omeprazole (20 mg/kg) was used as a standard. Interestingly, apocynin pre-treatment provided 93.5% gastroprotection against ethanol-induced ulceration. Biochemically, gastric mucin content was significantly increased with apocynin pre-treatment. This finding was further supported by alcian blue staining of stomach sections obtained from the different treated groups. Also, gastric juice volume and acidity were significantly reduced. Apocynin significantly ameliorated ethanol-induced oxidative stress by replenishing reduced glutathione and superoxide dismutase levels as well as reducing elevated malondialdehyde levels in gastric tissues. Besides, ethanol-induced pro-inflammatory response was significantly decreased by apocynin pre-treatment via reducing elevated levels of pro-inflammatory markers; interleukin-1β, tumor necrosis factor-α, cyclooxygenase-2 and inducible nitric oxide synthase. Additionally, caspase-3 tissue level was significantly reduced in apocynin pre-treated group. Interestingly, NADPH oxidase-1 (NOX-1) and NOX-4 up-regulation was shown to be partially involved in the pathogenesis of ethanol-induced gastric ulceration and was significantly reversed by apocynin pre-treatment. Gastroprotective properties of apocynin were confirmed by histopathological examination. It is worth mentioning that apocynin was superior in all aspects except gastric mucin content parameter where it was significantly increased by 13.5 folds in the omeprazole pre-treated group. This study was the first to show that apocynin is a promising gastroprotective agent against ethanol-induced gastric ulceration, partially via its anti-oxidant, anti-inflammatory, anti-apoptotic effects as well as down-regulating NOX-1 and NOX-4

  8. Rac1 Is Required for Cardiomyocyte Apoptosis During Hyperglycemia

    PubMed Central

    Shen, E.; Li, Yanwen; Li, Ying; Shan, Limei; Zhu, Huaqing; Feng, Qingping; Arnold, J. Malcolm O.; Peng, Tianqing

    2009-01-01

    OBJECTIVE Hyperglycemia induces reactive oxygen species (ROS) and apoptosis in cardiomyocytes, which contributes to diabetic cardiomyopathy. The present study was to investigate the role of Rac1 in ROS production and cardiomyocyte apoptosis during hyperglycemia. RESEARCH DESIGN AND METHODS Mice with cardiomyocyte-specific Rac1 knockout (Rac1-ko) were generated. Hyperglycemia was induced in Rac1-ko mice and their wild-type littermates by injection of streptozotocin (STZ). In cultured adult rat cardiomyocytes, apoptosis was induced by high glucose. RESULTS The results showed a mouse model of STZ-induced diabetes, 7 days of hyperglycemia-upregulated Rac1 and NADPH oxidase activation, elevated ROS production, and induced apoptosis in the heart. These effects of hyperglycemia were significantly decreased in Rac1-ko mice or wild-type mice treated with apocynin. Interestingly, deficiency of Rac1 or apocynin treatment significantly reduced hyperglycemia-induced mitochondrial ROS production in the heart. Deficiency of Rac1 also attenuated myocardial dysfunction after 2 months of STZ injection. In cultured cardiomyocytes, high glucose upregulated Rac1 and NADPH oxidase activity and induced apoptotic cell death, which were blocked by overexpression of a dominant negative mutant of Rac1, knockdown of gp91phox or p47phox, or NADPH oxidase inhibitor. In type 2 diabetic db/db mice, administration of Rac1 inhibitor, NSC23766, significantly inhibited NADPH oxidase activity and apoptosis and slightly improved myocardial function. CONCLUSIONS Rac1 is pivotal in hyperglycemia-induced apoptosis in cardiomyocytes. The role of Rac1 is mediated through NADPH oxidase activation and associated with mitochondrial ROS generation. Our study suggests that Rac1 may serve as a potential therapeutic target for cardiac complications of diabetes. PMID:19592621

  9. Hydrogen sulfide protects endothelial nitric oxide function under conditions of acute oxidative stress in vitro.

    PubMed

    Al-Magableh, Mohammad R; Kemp-Harper, Barbara K; Ng, Hooi H; Miller, Alyson A; Hart, Joanne L

    2014-01-01

    The aim of this study was to examine the ability of H2S, released from NaHS to protect vascular endothelial function under conditions of acute oxidative stress by scavenging superoxide anions (O2(-)) and suppressing vascular superoxide anion production. O2(-) was generated in Krebs' solution by reacting hypoxanthine with xanthine oxidase (Hx-XO) or with the O2(-) generator pyrogallol to model acute oxidative stress in vitro. O2(-) generation was measured by lucigenin-enhanced chemiluminescence. Functional responses in mouse aortic rings were assessed using a small vessel myograph. NaHS scavenged O2(-) in a concentration-dependent manner. Isolated aortic rings exposed to either Hx-XO or pyrogallol displayed significantly attenuated maximum vasorelaxation responses to the endothelium-dependent vasodilator acetylcholine, and significantly reduced NO bioavailability, which was completely reversed if vessels were pre-incubated with NaHS (100 μM). NADPH-stimulated aortic O2(-) production was significantly attenuated by the NADPH oxidase inhibitor diphenyl iodonium. Prior treatment of vessels with NaHS (100 nM-100 μM; 30 min) inhibited NADPH-stimulated aortic O2(-) production in a concentration-dependent manner. This effect persisted when NaHS was washed out prior to measuring NADPH-stimulated O2(-) production. These data show for the first time that NaHS directly scavenges O2(-) and suppresses vascular NADPH oxidase-derived O2(-) production in vitro. Furthermore, these properties protect endothelial function and NO bioavailability in an in vitro model of acute oxidative stress. These results suggest that H2S can elicit vasoprotection by both scavenging O2(-) and by reducing vascular NADPH oxidase-derived O2(-) production.

  10. Cytochrome c oxidase inhibition by calcium at physiological ionic composition of the medium: Implications for physiological significance of the effect.

    PubMed

    Vygodina, Tatiana V; Mukhaleva, Elizaveta; Azarkina, Natalia V; Konstantinov, Alexander A

    2017-12-01

    Cytochrome c oxidase (CcO) from mammalian mitochondria binds Ca 2+ and Na + in a special cation binding site. Binding of Ca 2+ brings about partial inhibition of the enzyme while Na + competes with Ca 2+ for the binding site and protects the enzyme from the inhibition [Vygodina, T., Kirichenko, A. and Konstantinov, A.A. (2013). Direct Regulation of Cytochrome c oxidase by Calcium Ions. PLoS One 8(9): e74436]. In the original studies, the inhibition was found to depend significantly on the ionic composition of the buffer. Here we describe inhibition of CcO by Ca 2+ in media containing the main ionic components of cytoplasm (150mM KCl, 12mM NaCl and 1mM MgCl 2 ). Under these conditions, Ca 2+ inhibits CcO with effective K i of 20-26μM, that is an order of magnitude higher than determined earlier in the absence of Na + . At physiological value of ionic strength, the inhibition can be observed at any turnover number of CcO, rather than only at low TN (<10s -1 ) as found previously. The inhibition requires partially oxidized state of cytochrome c and is favored by high ionic strength with a sharp transition at 0.1-0.2M. The high K i =20-26μM found for CcO inhibition by calcium matches closely the known value of "K m " for Ca 2+ -induced activation of the mitochondrial calcium uniporter. The inhibition of CcO by Ca 2+ is proposed to modulate mitochondrial Ca 2+ -uptake via the mitochondrial calcium uniporter, promote permeability transition pore opening and induce reduction of Mia40 in the mitochondrial intermembrane space. Copyright © 2017 Elsevier B.V. All rights reserved.

  11. Contrasting influence of NADPH and a NADPH-regenerating system on the metabolism of carbonyl-containing compounds in hepatic microsomes.

    PubMed

    Mazur, Christopher S; Kenneke, John F; Goldsmith, Michael-Rock; Brown, Cather

    2009-09-01

    Carbonyl containing xenobiotics may be susceptible to NADPH-dependent cytochrome P450 (P450) and carbonyl-reduction reactions. In vitro hepatic microsome assays are routinely supplied NADPH either by direct addition of NADPH or via an NADPH-regenerating system (NRS). In contrast to oxidative P450 transformations, which occur on the periphery of a microsome vesicle, intraluminal carbonyl reduction depends on transport of cofactors across the endoplasmic reticulum (ER) membrane into the lumen. Glucose 6-phosphate, a natural cofactor and component of the NRS matrix, is readily transported across the ER membrane and facilitates intraluminal NADPH production, whereas direct addition of NADPH has limited access to the lumen. In this study, we compared the effects of direct addition of NADPH and use of an NRS on the P450-mediated transformation of propiconazole and 11 beta-hydroxysteroid dehydrogenase type 1 (HSD1) carbonyl reduction of cortisone and the xenobiotic triadimefon in hepatic microsomes. Our results demonstrate that the use of NADPH rather than NRS can underestimate the kinetic rates of intraluminal carbonyl reduction, whereas P450-mediated transformations were unaffected. Therefore, in vitro depletion rates measured for a carbonyl-containing xenobiotic susceptible to both intraluminal carbonyl reduction and P450 processes may not be properly assessed with direct addition of NADPH. In addition, we used in silico predictions as follows: 1) to show that 11 beta-HSD1 carbonyl reduction was energetically more favorable than oxidative P450 transformation; and 2) to calculate chemical binding score and the distance between the carbonyl group and the hydride to be transferred by NADPH to identify other 11 beta-HSD1 substrates for which reaction kinetics may be underestimated by direct addition of NADPH.

  12. Omethoate treatment mitigates high salt stress inhibited maize seed germination.

    PubMed

    Yang, Kejun; Zhang, Yifei; Zhu, Lianhua; Li, Zuotong; Deng, Benliang

    2018-01-01

    Omethoate (OM) is a highly toxic organophophate insecticide, which is resistant to biodegradation in the environment and is widely used for pest control in agriculture. The effect of OM on maize seed germination was evaluated under salt stress. Salt (800mM) greatly reduced germination of maize seed and this could be reversed by OM. Additionally, H 2 O 2 treatment further improved the effect of OM on seed germination. Higher H 2 O 2 content was measured in OM treated seed compared to those with salt stress alone. Dimethylthiourea (DTMU), a specific scavenger of reactive oxygen species (ROS), inhibited the effect of OM on seed germination, as did IMZ (imidazole), an inhibitor of NADPH oxidase. Abscisic acid (ABA) inhibited the effect of OM on seed germination, whereas fluridone, a specific inhibitor of ABA biosynthesis, enhanced the effect of OM. Taken together, these findings suggest a role of ROS and ABA in the promotion of maize seed germination by OM under salt stress. Copyright © 2017 Elsevier Inc. All rights reserved.

  13. NADPH-generating systems in bacteria and archaea

    PubMed Central

    Spaans, Sebastiaan K.; Weusthuis, Ruud A.; van der Oost, John; Kengen, Servé W. M.

    2015-01-01

    Reduced nicotinamide adenine dinucleotide phosphate (NADPH) is an essential electron donor in all organisms. It provides the reducing power that drives numerous anabolic reactions, including those responsible for the biosynthesis of all major cell components and many products in biotechnology. The efficient synthesis of many of these products, however, is limited by the rate of NADPH regeneration. Hence, a thorough understanding of the reactions involved in the generation of NADPH is required to increase its turnover through rational strain improvement. Traditionally, the main engineering targets for increasing NADPH availability have included the dehydrogenase reactions of the oxidative pentose phosphate pathway and the isocitrate dehydrogenase step of the tricarboxylic acid (TCA) cycle. However, the importance of alternative NADPH-generating reactions has recently become evident. In the current review, the major canonical and non-canonical reactions involved in the production and regeneration of NADPH in prokaryotes are described, and their key enzymes are discussed. In addition, an overview of how different enzymes have been applied to increase NADPH availability and thereby enhance productivity is provided. PMID:26284036

  14. R1, a novel repressor of the human monoamine oxidase A.

    PubMed

    Chen, Kevin; Ou, Xiao-Ming; Chen, Gao; Choi, Si Ho; Shih, Jean C

    2005-03-25

    Monoamine oxidase catalyzes the oxidative deamination of a number of neurotransmitters. A deficiency in monoamine oxidase A results in aggressive behavior in both humans and mice. Studies on the regulation of monoamine oxidase A gene expression have shown that the Sp1 family is important for monoamine oxidase A expression. To search for novel transcription factors, the sequences of three Sp1 sites in the monoamine oxidase A core promoter were used in the yeast one-hybrid system to screen a human cDNA library. A novel repressor, R1 (RAM2), has been cloned. The R1 cDNA encodes a protein with 454 amino acids and an open reading frame at the 5'-end. The transfection of R1 in a human neuroblastoma cell line, SK-N-BE (2)-C, inhibited the monoamine oxidase A promoter and enzymatic activity. The degree of inhibition of monoamine oxidase A by R1 correlated with the level of R1 protein expression. R1 was also found to repress monoamine oxidase A promoter activity within a natural chromatin environment. A gel-shift assay indicated that the endogenous R1 protein in SK-N-BE (2)-C cells interacted with the R1 binding sequence. R1 also bound directly to the natural monoamine oxidase A promoter in vivo as shown by chromatin immunoprecipitation assay. Immunocytochemical analysis showed that R1 was expressed in both cytosol and nucleus, which suggested a role for R1 in transcriptional regulation. Northern blot analysis revealed the presence of endogenous R1 mRNA in human brain and peripheral tissues. Taken together, this study shows that R1 is a novel repressor that inhibits monoamine oxidase A gene expression.

  15. Toll-like receptor 4 signaling is associated with upregulated NADPH oxidase expression in peripheral T cells of children with autism.

    PubMed

    Nadeem, Ahmed; Ahmad, Sheikh F; Bakheet, Saleh A; Al-Harbi, Naif O; Al-Ayadhi, Laila Y; Attia, Sabry M; Zoheir, Khairy M A

    2017-03-01

    Autism spectrum disorders (ASD) affect millions of children worldwide, and are characterized by impairment in social interaction and communication, and specific repetitive behavioral patterns. Growing evidence highlights a role of toll-like receptors (TLRs) in the pathogenesis of ASD. Specifically, TLR-4 activation has been shown to be associated with increased pro-inflammatory cytokines as well as autistic symptoms in offspring. NADPH oxidase (NOX-2) derived reactive oxygen species (ROS) have also been shown to play pathogenic role under inflammatory conditions. However, the role of TLR-4 in the regulation of NOX-2 derived ROS has not been explored in ASD, particularly in T cells. Therefore, this study explored TLR-4 and NOX-2 related signaling in peripheral T cells of ASD patients (n=35) and age-matched typically developing children (n=30). In this study, we find that ASD individuals have increased TLR-4 expression on T cells which is associated with increased NOX-2 expression and ROS generation as compared to typically developing children. Moreover, activation of TLR-4 on T cells by lipopolysaccharide (LPS) in vitro leads to enhanced generation of NOX-2 derived ROS via nuclear factor kappa-light-chain-enhancer of activated B cells (NFκB) pathway. These data support a link between T cell TLR-4 activation and NOX-2/ROS upregulation in ASD patients. Our study has implications in the context of neuroinflammation observed in ASD patients as ROS may lead to amplification and perpetuation of inflammation both in the periphery and central nervous system. Our data also suggest that therapeutic targeting of TLR-4 signaling may lead to reduction in inflammation of ASD patients. Copyright © 2016 Elsevier Inc. All rights reserved.

  16. The NADPH Oxidases DUOX1 and NOX2 Play Distinct Roles in Redox Regulation of Epidermal Growth Factor Receptor Signaling.

    PubMed

    Heppner, David E; Hristova, Milena; Dustin, Christopher M; Danyal, Karamatullah; Habibovic, Aida; van der Vliet, Albert

    2016-10-28

    The epidermal growth factor receptor (EGFR) plays a critical role in regulating airway epithelial homeostasis and responses to injury. Activation of EGFR is regulated by redox-dependent processes involving reversible cysteine oxidation by reactive oxygen species (ROS) and involves both ligand-dependent and -independent mechanisms, but the precise source(s) of ROS and the molecular mechanisms that control tyrosine kinase activity are incompletely understood. Here, we demonstrate that stimulation of EGFR activation by ATP in airway epithelial cells is closely associated with dynamic reversible oxidation of cysteine residues via sequential sulfenylation and S-glutathionylation within EGFR and the non-receptor-tyrosine kinase Src. Moreover, the intrinsic kinase activity of recombinant Src or EGFR was in both cases enhanced by H 2 O 2 but not by GSSG, indicating that the intermediate sulfenylation is the activating modification. H 2 O 2 -induced increase in EGFR tyrosine kinase activity was not observed with the C797S variant, confirming Cys-797 as the redox-sensitive cysteine residue that regulates kinase activity. Redox-dependent regulation of EGFR activation in airway epithelial cells was found to strongly depend on activation of either the NADPH oxidase DUOX1 or the homolog NOX2, depending on the activation mechanism. Whereas DUOX1 and Src play a primary role in EGFR transactivation by wound-derived signals such as ATP, direct ligand-dependent EGFR activation primarily involves NOX2 with a secondary role for DUOX1 and Src. Collectively, our findings establish that redox-dependent EGFR kinase activation involves a dynamic and reversible cysteine oxidation mechanism and that this activation mechanism variably involves DUOX1 and NOX2. © 2016 by The American Society for Biochemistry and Molecular Biology, Inc.

  17. Inhibition of monoamine oxidase A increases recovery after experimental cardiac arrest.

    PubMed

    Vuohelainen, Vilma; Hämäläinen, Mari; Paavonen, Timo; Karlsson, Sari; Moilanen, Eeva; Mennander, Ari

    2015-10-01

    Perioperative myocardial infarction (MI) with ischaemia-reperfusion injury (IRI) is a devastating entity occurring in 1-2% of patients after cardiac surgery. The molecular pathway leading to myocardial cellular destruction after MI may include monoamine oxidases. We experimentally investigated whether moclobemide, a monoamine oxidase inhibitor, enhances myocardial recovery after cardiac arrest and MI. Fifty-six syngeneic Fischer rats underwent heterotopic cardiac transplantation to induce reversible IRI after cardiac arrest. Twenty-eight rats also underwent permanent ligation of the left anterior descending coronary artery to induce MI after cardiac arrest. Twenty-eight rats with or without MI were treated with subcutaneous moclobemide 10 mg/kg/day. Methods used to study myocardial recovery were microdialysis for intramyocardial metabolism, histology and quantitative reverse-transcription polymerase chain reaction for high-mobility group box-1 (HMGB1), haeme oxygenase-1 (HO-1), interleukin-6, hypoxia-inducible factor 1α and macrophages (CD68). Pyruvate increased in MI treated with moclobemide versus IRI with moclobemide (29.19 ± 7.64 vs 13.86 ± 8.49 µM, P = 0.028), reflecting metabolic activity after cardiac arrest and reperfusion. Myocardial inflammation increased in MI compared with IRI after 1 h (0.80 ± 0.56 vs 0, point score units [PSUs], P = 0.003), but decreased after 5 days in MI treated with moclobemide versus MI alone (0.80 ± 0.83 vs 2.00 ± 0.70, PSU, P = 0.033). Expressions of HMGB1, CD68 and HO-1 decreased in MI treated with moclobemide versus MI alone (1.33 ± 0.20 vs 1.75 ± 0.24, fold changes [FCs], P = 0.028; 5.15 ± 1.10 vs 9.59 ± 2.75, FC, P = 0.050; 10.41 ± 4.17 vs 21.28 ± 10.01, FC, P = 0.047), indicating myocardial recovery and increased cellularity of remote intramyocardial arteries. Moclobemide enhances myocardial recovery after cardiac arrest and MI; inhibition of remote myocardial changes may be achieved by targeting treatment

  18. Increasing Glucose 6-Phosphate Dehydrogenase Activity Restores Redox Balance in Vascular Endothelial Cells Exposed to High Glucose

    PubMed Central

    Zhu, Bo; Hu, Ji; Liew, Chong Wee; Zhang, Yingyi; Leopold, Jane A.; Handy, Diane E.; Loscalzo, Joseph; Stanton, Robert C.

    2012-01-01

    Previous studies have shown that high glucose increases reactive oxygen species (ROS) in endothelial cells that contributes to vascular dysfunction and atherosclerosis. Accumulation of ROS is due to dysregulated redox balance between ROS-producing systems and antioxidant systems. Previous research from our laboratory has shown that high glucose decreases the principal cellular reductant, NADPH by impairing the activity of glucose 6-phosphate dehydrogenase (G6PD). We and others also have shown that the high glucose-induced decrease in G6PD activity is mediated, at least in part, by cAMP-dependent protein kinase A (PKA). As both the major antioxidant enzymes and NADPH oxidase, a major source of ROS, use NADPH as substrate, we explored whether G6PD activity was a critical mediator of redox balance. We found that overexpression of G6PD by pAD-G6PD infection restored redox balance. Moreover inhibition of PKA decreased ROS accumulation and increased redox enzymes, while not altering the protein expression level of redox enzymes. Interestingly, high glucose stimulated an increase in NADPH oxidase (NOX) and colocalization of G6PD with NOX, which was inhibited by the PKA inhibitor. Lastly, inhibition of PKA ameliorated high glucose mediated increase in cell death and inhibition of cell growth. These studies illustrate that increasing G6PD activity restores redox balance in endothelial cells exposed to high glucose, which is a potentially important therapeutic target to protect ECs from the deleterious effects of high glucose. PMID:23185302

  19. NADPH Oxidase-1 Plays a Key Role in Keratinocyte Responses to UV Radiation and UVB-Induced Skin Carcinogenesis.

    PubMed

    Raad, Houssam; Serrano-Sanchez, Martin; Harfouche, Ghida; Mahfouf, Walid; Bortolotto, Doriane; Bergeron, Vanessa; Kasraian, Zeinab; Dousset, Lea; Hosseini, Mohsen; Taieb, Alain; Rezvani, Hamid Reza

    2017-06-01

    The nicotinamide adenine dinucleotide phosphate oxidase (NOX) family enzymes are involved in several physiological functions. However, their roles in keratinocyte responses to UV radiation have not been clearly elucidated. This study shows that, among other NOX family members, UVB irradiation results in a biphasic activation of NOX1 that plays a critical role in defining keratinocyte fate through the modulation of the DNA damage response network. Indeed, suppression of both bursts of UVB-induced NOX1 activation by using a specific peptide inhibitor of NOX1 (InhNOX1) is associated with increased nucleotide excision repair efficiency and reduction of apoptosis, which is finally translated into decreased photocarcinogenesis. On the contrary, when only the second peak of UVB-induced NOX1 activation is blocked, both nucleotide excision repair efficiency and apoptosis are decreased. Our results show that inhibition of NOX1 activation could be a promising target for the prevention and treatment of UVB-induced skin cancer in nucleotide excision repair-proficient and -deficient patients. Copyright © 2017 The Authors. Published by Elsevier Inc. All rights reserved.

  20. The monoamine oxidase inhibition properties of selected structural analogues of methylene blue

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

    Delport, Anzelle

    The thionine dye, methylene blue (MB), is a potent inhibitor of monoamine oxidase (MAO) A, a property that may, at least in part, mediate its antidepressant effects in humans and animals. The central inhibition of MAO-A by MB has also been linked to serotonin toxicity (ST) which may arise when MB is used in combination with serotonergic drugs. Structural analogues and the principal metabolite of MB, azure B, have also been reported to inhibit the MAO enzymes, with all compounds exhibiting specificity for the MAO-A isoform. To expand on the structure-activity relationships (SARs) of MAO inhibition by MB analogues, themore » present study investigates the human MAO inhibition properties of five MB analogues: neutral red, Nile blue, new methylene blue, cresyl violet and 1,9-dimethyl methylene blue. Similar to MB, these analogues also are specific MAO-A inhibitors with cresyl violet (IC{sub 50} = 0.0037 μM), Nile blue (IC{sub 50} = 0.0077 μM) and 1,9-dimethyl methylene blue (IC{sub 50} = 0.018 μM) exhibiting higher potency inhibition compared to MB (IC{sub 50} = 0.07 μM). Nile blue also represents a potent MAO-B inhibitor with an IC{sub 50} value of 0.012 μM. From the results it may be concluded that non-thionine MB analogues (e.g. cresyl violet and Nile blue) also may exhibit potent MAO inhibition, a property which should be considered when using these compounds in pharmacological studies. Benzophenoxazines such as cresyl violet and Nile blue are, similar to phenothiazines (e.g. MB), representative of high potency MAO-A inhibitors with a potential risk of ST. - Highlights: • MB analogues, cresyl violet and Nile blue, are high potency MAO-A inhibitors. • Nile blue also represents a potent MAO-B inhibitor. • Potent MAO-A inhibition should alert to potential serotonin toxicity.« less

  1. The separate and combined effects of monoamine oxidase A inhibition and nicotine on resting state EEG.

    PubMed

    Smith, Dylan M; Fisher, Derek; Blier, Pierre; Ilivitsky, Vadim; Knott, Verner

    2016-01-01

    While nicotine is often associated with the neuropsychological effects of tobacco smoke, the robust monoamine oxidase (MAO) inhibition observed in chronic smokers is also likely to play a role. Electroencephalographically-indexed alterations in baseline neural oscillations by nicotine have previously been reported in both smokers and non-smokers, however, little is known about the effects of MAO inhibition in combination with nicotine on resting state EEG. In a sample of 24 healthy non-smoking males, the effects of 6 mg nicotine gum, as well as MAO-A inhibition via 75 mg moclobemide, were investigated in separate and combined conditions over four separate test sessions. Drug effects were observed in the alpha2, beta2, and theta band frequencies. Nicotine increased alpha2 power, and moclobemide decreased beta2 power. Theta power was decreased most robustly by the combination of both drugs. Therefore, this study demonstrated that the nicotinic and MAO inhibiting properties of tobacco may differentially influence fast-wave oscillations (alpha2 and beta2), while acting in synergy to influence theta oscillations. © The Author(s) 2015.

  2. Immunological comparison of sulfite oxidase

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

    Pollock, V.; Barber, M.J.

    1991-03-11

    Polyclonal antibodies (rabbit), elicited against FPLC-purified chicken and rat liver sulfite oxidase (SO), have been examined for inhibition and binding to purified chicken (C), rat (R), bovine (B), alligator (A) and shark (S) liver enzymes. Anti-CSO IgG cross-reacted with all five enzymes, with varying affinities, in the order CSO=ASO{gt}RSO{gt}BSO{gt}SSO. Anti-ROS IgG also cross-reacted with all five enzymes in the order RSO{gt}CSO=ASO{gt}BSO{gt}SSO. Anti-CSO IgG inhibited sulfite:cyt. c reductase (S:CR), sulfite:ferricyanide reductase (S:FR) and sulfite:dichlorophenolindophenol reductase (S:DR) activities of CSO to different extents (S:CR{gt}S:FR=S:DR). Similar differential inhibition was found for anti-ROS IgG and RSO S:CR, S:FR and S:DR activities. Anti-CSO IgG inhibitedmore » S:CR activities in the order CSO=ASO{much gt}SSO{gt}BSO. RSO was uninhibited. For anti-RSO IgG the inhibition order was RSO{gt}SSO{gt}BSO{gt}ASO. CSO was uninhibited. Anti-CSO and RSO IgGs partially inhibited Chlorella nitrate reductase (NR). Minor cross-reactivity was found for xanthine oxidase. Common antigenic determinants for all five SO's and NR are indicated.« less

  3. Reactive oxygen species are involved in regulating alpha1-adrenoceptor-activated vascular smooth muscle contraction.

    PubMed

    Tsai, Ming-Ho; Jiang, Meei Jyh

    2010-08-23

    Reactive oxygen species (ROS) were shown to mediate aberrant contractility in hypertension, yet the physiological roles of ROS in vascular smooth muscle contraction have remained elusive. This study aimed to examine whether ROS regulate alpha1-adrenoceptor-activated contraction by altering myosin phosphatase activities. Using endothelium-denuded rat tail artery (RTA) strips, effects of anti-oxidants on isometric force, ROS production, phosphorylation of the 20-kDa myosin light chain (MLC20), and myosin phosphatase stimulated by alpha1-adrenoceptor agonist phenylephrine were examined. An antioxidant, N-acetyl-L-cysteine (NAC), and two NADPH oxidase inhibitors, apocynin and VAS2870, dose-dependently inhibited contraction activated by phenylephrine. Phenylephrine stimulated superoxide anion production that was diminished by the pretreatment of apocynin, VAS2870, superoxide scavenger tiron or mitochondria inhibitor rotenone, but not by xanthine oxidase inhibitor allopurinol or cyclooxygenase inhibitor indomethacin. Concurrently, NADPH oxidase activity in RTA homogenates increased within 1 min upon phenylephrine stimulation, sustained for 10 min, and was abolished by the co-treatment with apocynin, but not allopurinol or rotenone. Phenylephrine-induced MLC20 phosphorylation was dose-dependently decreased by apocynin. Furthermore, apocynin inhibited phenylephrine-stimulated RhoA translocation to plasma membrane and phosphorylation of both myosin phosphatase regulatory subunit MYPT1Thr855 and myosin phosphatase inhibitor CPI-17Thr38. ROS, probably derived from NADPH oxidase and mitochondria, partially regulate alpha1-adrenoceptor-activated smooth muscle contraction by altering myosin phosphatase-mediated MLC20 phosphorylation through both RhoA/Rho kinase- and CPI-17-dependent pathways.

  4. Functional Analysis of the Trichoderma harzianum nox1 Gene, Encoding an NADPH Oxidase, Relates Production of Reactive Oxygen Species to Specific Biocontrol Activity against Pythium ultimum▿†

    PubMed Central

    Montero-Barrientos, M.; Hermosa, R.; Cardoza, R. E.; Gutiérrez, S.; Monte, E.

    2011-01-01

    The synthesis of reactive oxygen species (ROS) is one of the first events following pathogenic interactions in eukaryotic cells, and NADPH oxidases are involved in the formation of such ROS. The nox1 gene of Trichoderma harzianum was cloned, and its role in antagonism against phytopathogens was analyzed in nox1-overexpressed transformants. The increased levels of nox1 expression in these transformants were accompanied by an increase in ROS production during their direct confrontation with Pythium ultimum. The transformants displayed an increased hydrolytic pattern, as determined by comparing protease, cellulase, and chitinase activities with those for the wild type. In confrontation assays against P. ultimum the nox1-overexpressed transformants were more effective than the wild type, but not in assays against Botrytis cinerea or Rhizoctonia solani. A transcriptomic analysis using a Trichoderma high-density oligonucleotide (HDO) microarray also showed that, compared to gene expression for the interaction of wild-type T. harzianum and P. ultimum, genes related to protease, cellulase, and chitinase activities were differentially upregulated in the interaction of a nox1-overexpressed transformant with this pathogen. Our results show that nox1 is involved in T. harzianum ROS production and antagonism against P. ultimum. PMID:21421791

  5. Silencing C19-GA 2-oxidases induces parthenocarpic development and inhibits lateral branching in tomato plants

    PubMed Central

    Martínez-Bello, Liliam; Moritz, Thomas; López-Díaz, Isabel

    2015-01-01

    Gibberellins (GAs) are phytohormones that regulate a wide range of developmental processes in plants. Levels of active GAs are regulated by biosynthetic and catabolic enzymes like the GA 2-oxidases (GA2oxs). In tomato (Solanum lycopersicum L.) C19 GA2oxs are encoded by a small multigenic family of five members with some degree of redundancy. In order to investigate their roles in tomato, the silencing of all five genes in transgenic plants was induced. A significant increase in active GA4 content was found in the ovaries of transgenic plants. In addition, the transgenic unfertilized ovaries were much bigger than wild-type ovaries (about 30 times) and a certain proportion (5–37%) were able to develop parthenocarpically. Among the GA2ox family, genes GA2ox1 and -2 seem to be the most relevant for this phenotype since their expression was induced in unfertilized ovaries and repressed in developing fruits, inversely correlating with ovary growth. Interestingly, transgenic lines exhibited a significant inhibition of branching and a higher content of active GA4 in axillary buds. This phenotype was reverted, in transgenic plants, by the application of paclobutrazol, a GA biosynthesis inhibitor, suggesting a role for GAs as repressors of branching. In summary, this work demonstrates that GA 2-oxidases regulate gibberellin levels in ovaries and axillary buds of tomato plants and their silencing is responsible for parthenocarpic fruit growth and branching inhibition. PMID:26093022

  6. IFNβ/TNFα synergism induces a non-canonical STAT2/IRF9-dependent pathway triggering a novel DUOX2 NADPH Oxidase-mediated airway antiviral response

    PubMed Central

    Fink, Karin; Martin, Lydie; Mukawera, Esperance; Chartier, Stéfany; De Deken, Xavier; Brochiero, Emmanuelle; Miot, Françoise; Grandvaux, Nathalie

    2013-01-01

    Airway epithelial cells are key initial innate immune responders in the fight against respiratory viruses, primarily via the secretion of antiviral and proinflammatory cytokines that act in an autocrine/paracrine fashion to trigger the establishment of an antiviral state. It is currently thought that the early antiviral state in airway epithelial cells primarily relies on IFNβ secretion and the subsequent activation of the interferon-stimulated gene factor 3 (ISGF3) transcription factor complex, composed of STAT1, STAT2 and IRF9, which regulates the expression of a panoply of interferon-stimulated genes encoding proteins with antiviral activities. However, the specific pathways engaged by the synergistic action of different cytokines during viral infections, and the resulting physiological outcomes are still ill-defined. Here, we unveil a novel delayed antiviral response in the airways, which is initiated by the synergistic autocrine/paracrine action of IFNβ and TNFα, and signals through a non-canonical STAT2- and IRF9-dependent, but STAT1-independent cascade. This pathway ultimately leads to the late induction of the DUOX2 NADPH oxidase expression. Importantly, our study uncovers that the development of the antiviral state relies on DUOX2-dependent H2O2 production. Key antiviral pathways are often targeted by evasion strategies evolved by various pathogenic viruses. In this regard, the importance of the novel DUOX2-dependent antiviral pathway is further underlined by the observation that the human respiratory syncytial virus is able to subvert DUOX2 induction. PMID:23545780

  7. Effect of contraceptive steroids on monoamine oxidase activity

    PubMed Central

    Southgate, Jennifer; Collins, G. G. S.; Pryse-Davies, J.; Sandler, M.

    1969-01-01

    Cyclical variations in monoamine oxidase activity during the human menstrual cycle, specific to the endometrium and modified in women undergoing contraceptive steroid treatment, may reflect changes in hormonal environment. Treatment of rats with individual constituents of the contraceptive pill causes analogous changes: oestrogens inhibit and progestogens potentiate uterine monoamine oxidase activity. ImagesFig. 2Fig. 3

  8. Class IA phosphoinositide 3-kinase β and δ regulate neutrophil oxidase activation in response to Aspergillus fumigatus hyphae.

    PubMed

    Boyle, Keith B; Gyori, David; Sindrilaru, Anca; Scharffetter-Kochanek, Karin; Taylor, Philip R; Mócsai, Attila; Stephens, Len R; Hawkins, Phillip T

    2011-03-01

    An effective immune response to the ubiquitous fungus Aspergillus fumigatus is dependent upon production of reactive oxygen species (ROS) by the NADPH oxidase. This is evidenced by the acute sensitivity of oxidase-deficient humans and mice to invasive aspergillosis. Neutrophils are recruited to the lungs shortly postinfection and respond by phagocytosing conidia and mediating extracellular killing of germinated hyphae in a ROS-dependent manner. However, the signaling mechanisms regulating the generation of ROS in response to hyphae are poorly understood. PI3Ks are important regulators of numerous cellular processes, with much recent work describing unique roles for the different class I PI3K isoforms. We showed by live-cell imaging that the lipid products of class I PI3Ks accumulated at the hyphal-bound neutrophil plasma membrane. Further, we used pharmacological and genetic approaches to demonstrate essential, but overlapping, roles for PI3Kβ and PI3Kδ in the ROS and spreading responses of murine neutrophils to Aspergillus hyphae. Hyphal-induced ROS responses were substantially inhibited by deletion of the common β2-integrin subunit CD18, with only a minor, redundant role for Dectin-1. However, addition of soluble algal glucans plus the genetic deletion of CD18 were required to significantly inhibit activation of the PI3K-effector protein kinase B. Hyphal ROS responses were also totally dependent on the presence of Syk, but not its ITAM-containing adaptor proteins FcRγ or DAP12, and the Vav family of Rac-guanine nucleotide exchange factors. These results start to define the signaling network controlling neutrophil ROS responses to A. fumigatus hyphae.

  9. Sildenafil citrate and sildenafil nitrate (NCX 911) are potent inhibitors of superoxide formation and gp91phox expression in porcine pulmonary artery endothelial cells.

    PubMed

    Muzaffar, Saima; Shukla, Nilima; Srivastava, Amit; Angelini, Gianni D; Jeremy, Jamie Y

    2005-09-01

    Acute respiratory distress syndrome (ARDS) is associated with increased superoxide (O(2)(*-)) formation in the pulmonary vasculature and negation of the bioavailability of nitric oxide (NO). Since NO inhibits NADPH oxidase expression through a cyclic GMP-mediated mechanism, sildenafil, a type V phosphodiesterase inhibitor, may be therapeutically effective in ARDS through an augmentation of NO-mediated inhibition of NADPH oxidase. Therefore, the effect of sildenafil citrate and NO-donating sildenafil (NCX 911) on O(2)(*-) formation and gp91(phox) (active catalytic subunit of NADPH oxidase) expression was investigated in cultured porcine pulmonary artery endothelial cells (PAECs). PAECs were incubated with 10 nM TXA(2) analogue, 9,11-dideoxy-9alpha,11alpha-methanoepoxy-prostaglandin F(2alpha) (U46619) (+/-sildenafil or NCX 911), for 16 h and O(2)(*-) formation measured spectrophometrically and gp91(phox) using Western blotting. The role of the NO-cGMP axis was studied using morpholinosydnonimine hydrochloride (SIN-1), the diethylamine/NO complex (DETA-NONOate), the guanylyl cyclase inhibitor, 1H-{1,2,4}oxadiazolo{4,3-a}quinoxalin-1-one (ODQ), and the protein kinase G inhibitor, 8-bromoguanosine-3',5'-cyclic monophosphorothioate, Rp-isomer (Rp-8-Br-cGMPS). NO release was studied using a fluorescence assay and O(2)(*-)-NO interactions by measuring nitrites. After a 16-h incubation with 10 nM U46619, both NCX 911 and sildenafil elicited a concentration-dependent inhibition of O(2)(*-) formation and gp91(phox) expression, NCX 911 being more potent (IC(50); 0.26 nM) than sildenafil citrate (IC(50); 1.85 nM). These inhibitory effects were reversed by 1 microM ODQ and 10 microM Rp-8-Br-cGMPS. NCX 911 stimulated the formation of cGMP in PAECs and generated NO in a cell-free system to a greater degree than sildenafil citrate. The inhibitory effect of sildenafil was augmented by 1 muM SIN-1 and blocked partially by the eNOS inhibitor 10 microM N(5)-(1-iminoethyl)-ornithine (L

  10. Cytochrome P450 Monooxygenase Activity in the Dark Southern Subterranean Termite (Isoptera: Rhinotermitidae)

    Treesearch

    Steven M. Valles; Weste L.A. Osbrink; Faith M. Oi; Richard J. Brenner; Janine E. Powell

    1998-01-01

    Microsomal oxidases were characterized using surrogate substrates in the economically important dark southern subterranean termite, Reticulitermes virginicus (Banks). Aldrin epoxitlase activity required NADPH and was inhibited by carbon monoxide and piperonyl butoxide (I50 = 4.72 (+,-) 0.31 X 1O-10 M), indicating that...

  11. The Tick Salivary Protein Sialostatin L2 Inhibits Caspase-1-Mediated Inflammation during Anaplasma phagocytophilum Infection

    PubMed Central

    Chen, Gang; Wang, Xiaowei; Severo, Maiara S.; Sakhon, Olivia S.; Sohail, Mohammad; Brown, Lindsey J.; Sircar, Mayukh; Snyder, Greg A.; Sundberg, Eric J.; Ulland, Tyler K.; Olivier, Alicia K.; Andersen, John F.; Zhou, Yi; Shi, Guo-Ping; Sutterwala, Fayyaz S.; Kotsyfakis, Michail

    2014-01-01

    Saliva from arthropod vectors facilitates blood feeding by altering host inflammation. Whether arthropod saliva counters inflammasome signaling, a protein scaffold that regulates the activity of caspase-1 and cleavage of interleukin-1β (IL-1β) and IL-18 into mature molecules, remains elusive. In this study, we provide evidence that a tick salivary protein, sialostatin L2, inhibits inflammasome formation during pathogen infection. We show that sialostatin L2 targets caspase-1 activity during host stimulation with the rickettsial agent Anaplasma phagocytophilum. A. phagocytophilum causes macrophage activation and hemophagocytic syndrome features. The effect of sialostatin L2 in macrophages was not due to direct caspase-1 enzymatic inhibition, and it did not rely on nuclear factor κB or cathepsin L signaling. Reactive oxygen species from NADPH oxidase and the Loop2 domain of sialostatin L2 were important for the regulatory process. Altogether, our data expand the knowledge of immunoregulatory pathways of tick salivary proteins and unveil an important finding in inflammasome biology. PMID:24686067

  12. Correlation of enteric NADPH-d positive cell counts with the duration of incubation period in NADPH-d histochemistry.

    PubMed

    Cserni, Tamas; O' Donnel, Annemarie; Paran, Sri; Puri, Prem

    2009-03-01

    Nicotinamide adenine dinucleotide phosphate-diaphorase (NADPH-d) staining can be used in the enteric nervous system to determine nitrergic neuronal counts, critical in motility disorders such as intestinal neuronal dysplasia and hypoganglionosis. The reported incubation periods of specimens with NADPH-d staining solution has varied from 2 to 24 h. The aim of this study is to investigate the impact of the incubation period on the overall NADPH-d positive cell counts in porcine rectal submucosal plexus. The submucosal plexus of rectal specimens from 12-week-old pigs (n = 5) were studied. Conventional frozen sections were used to identify nitrergic neurons while whole-mount preparations were used to quantify the effect of prolonged duration of incubation on positively identified ganglion cells with NADPH-d histochemistry. The same submucosal ganglia on the conventional sections, and a minimum of 12 ganglia per whole-mount preparation specimen were photographed sequentially at 2, 6, and 24 h and used to count the number of nitrergic cells per ganglion. The same staining solution was used throughout the experiment. Results were analysed using a one-way ANOVA test. Prolonged incubation with the staining solution revealed new NADPH-d positive cells in the ganglia on the conventional sections. The total number of neurons counted in the 12 adjacent ganglia in the whole-mount specimens was 180 +/- 55, the mean neuronal cell per ganglion was 15 +/- 8 after 2 h of incubation. This increased to 357 +/- 17, and to 29 +/- 12 after 6 h (p < 0.05). A further increase was observed of 515 +/- 19 and 43 +/- 17 after 24 h (p < 0.05). When the photomicrographs were retrospectively analysed, not even the outline of the neuronal cells that stained with prolonged incubation was evident at the earlier time points. NADPH-d positive cell counts increase in proportion to the duration of incubation in NADPH-d histochemistry. Comparative studies attempting to quantify nitrergic cell counts in

  13. Naringin Attenuates Cerebral Ischemia-Reperfusion Injury Through Inhibiting Peroxynitrite-Mediated Mitophagy Activation.

    PubMed

    Feng, Jinghan; Chen, Xingmiao; Lu, Shengwen; Li, Wenting; Yang, Dan; Su, Weiwei; Wang, Xijun; Shen, Jiangang

    2018-04-07

    Excessive autophagy/mitophagy plays important roles during cerebral ischemia-reperfusion (I/R) injury. Peroxynitrite (ONOO - ), a representative reactive nitrogen species, mediates excessive mitophagy activation and exacerbates cerebral I/R injury. In the present study, we tested the hypothesis that naringin, a natural antioxidant, could inhibit ONOO - -mediated mitophagy activation and attenuate cerebral I/R injury. Firstly, we demonstrated that naringin possessed strong ONOO - scavenging capability and also inhibited the production of superoxide and nitric oxide in SH-SY5Y cells exposed to 10 h oxygen-glucose-deprivation plus 14 h of reoxygenation or ONOO - donor 3-morpholinosydnonimine conditions. Naringin also inhibited the expression of NADPH oxidase subunits and iNOS in rat brains subjected to 2 h ischemia plus 22 h reperfusion. Next, we found that naringin was able to cross the blood-brain barrier, and naringin decreased neurological deficit score, reduced infarct size, and attenuated apoptotic cell death in the ischemia-reperfused rat brains. Furthermore, naringin reduced 3-nitrotyrosine formation, decreased the ratio of LC3-II to LC3-I in mitochondrial fraction, and inhibited the translocation of Parkin to the mitochondria. Taken together, naringin could be a potential therapeutic agent to prevent the brain from I/R injury via attenuating ONOO - -mediated excessive mitophagy.

  14. Ubiquinol-binding site in the alternative oxidase: mutagenesis reveals features important for substrate binding and inhibition.

    PubMed

    Albury, Mary S; Elliott, Catherine; Moore, Anthony L

    2010-12-01

    The alternative oxidase (AOX) is a non-protonmotive ubiquinol oxidase that is found in all plants, some fungi, green algae, bacteria and pathogenic protozoa. The lack of AOX in the mammalian host renders this protein an important potential therapeutic target in the treatment of pathogenic protozoan infections. Bioinformatic searches revealed that, within a putative ubiquinol-binding crevice in AOX, Gln242, Asn247, Tyr253, Ser256, His261 and Arg262 were highly conserved. To confirm that these amino-acid residues are important for ubiquinol-binding and hence activity substitution mutations were generated and characterised. Assessment of AOX activity in isolated Schizosaccharomyces pombe mitochondria revealed that mutation of either Gln242, Ser256, His261 and Arg262 resulted in >90% inhibition of antimycin A-insensitive respiration suggesting that hydroxyl, guanidino, imidazole groups, polar and charged residues in addition to the size of the amino-acid chain are important for ubiquinone-binding. Substitution of Asn247 with glutamine or Tyr253 with phenylalanine had little effect upon the respiratory rate indicating that these residues are not critical for AOX activity. However replacement of Tyr253 by alanine resulted in a 72% loss of activity suggesting that the benzoquinone group and not hydroxyl group is important for quinol binding. These results provide important new insights into the ubiquinol-binding site of the alternative oxidase, the identity of which maybe important for future rational drug design. Copyright © 2010 Elsevier B.V. All rights reserved.

  15. A Mycobacterium tuberculosis Cytochrome bd Oxidase Mutant Is Hypersensitive to Bedaquiline

    PubMed Central

    Hartman, Travis E.

    2014-01-01

    ABSTRACT The new medicinal compound bedaquiline (BDQ) kills Mycobacterium tuberculosis by inhibiting F1Fo-ATP synthase. BDQ is bacteriostatic for 4 to 7 days and kills relatively slowly compared to other frontline tuberculosis (TB) drugs. Here we show that killing with BDQ can be improved significantly by inhibiting cytochrome bd oxidase, a non-proton-pumping terminal oxidase. BDQ was instantly bactericidal against a cytochrome bd oxidase null mutant of M. tuberculosis, and the rate of killing was increased by more than 50%. We propose that this exclusively bacterial enzyme should be a high-priority target for new drug discovery. PMID:25028424

  16. Quantitative flux analysis reveals folate-dependent NADPH production

    NASA Astrophysics Data System (ADS)

    Fan, Jing; Ye, Jiangbin; Kamphorst, Jurre J.; Shlomi, Tomer; Thompson, Craig B.; Rabinowitz, Joshua D.

    2014-06-01

    ATP is the dominant energy source in animals for mechanical and electrical work (for example, muscle contraction or neuronal firing). For chemical work, there is an equally important role for NADPH, which powers redox defence and reductive biosynthesis. The most direct route to produce NADPH from glucose is the oxidative pentose phosphate pathway, with malic enzyme sometimes also important. Although the relative contribution of glycolysis and oxidative phosphorylation to ATP production has been extensively analysed, similar analysis of NADPH metabolism has been lacking. Here we demonstrate the ability to directly track, by liquid chromatography-mass spectrometry, the passage of deuterium from labelled substrates into NADPH, and combine this approach with carbon labelling and mathematical modelling to measure NADPH fluxes. In proliferating cells, the largest contributor to cytosolic NADPH is the oxidative pentose phosphate pathway. Surprisingly, a nearly comparable contribution comes from serine-driven one-carbon metabolism, in which oxidation of methylene tetrahydrofolate to 10-formyl-tetrahydrofolate is coupled to reduction of NADP+ to NADPH. Moreover, tracing of mitochondrial one-carbon metabolism revealed complete oxidation of 10-formyl-tetrahydrofolate to make NADPH. As folate metabolism has not previously been considered an NADPH producer, confirmation of its functional significance was undertaken through knockdown of methylenetetrahydrofolate dehydrogenase (MTHFD) genes. Depletion of either the cytosolic or mitochondrial MTHFD isozyme resulted in decreased cellular NADPH/NADP+ and reduced/oxidized glutathione ratios (GSH/GSSG) and increased cell sensitivity to oxidative stress. Thus, although the importance of folate metabolism for proliferating cells has been long recognized and attributed to its function of producing one-carbon units for nucleic acid synthesis, another crucial function of this pathway is generating reducing power.

  17. Tempol, an intracellular antioxidant, inhibits tissue factor expression, attenuates dendritic cell function, and is partially protective in a murine model of cerebral malaria.

    PubMed

    Francischetti, Ivo M B; Gordon, Emile; Bizzarro, Bruna; Gera, Nidhi; Andrade, Bruno B; Oliveira, Fabiano; Ma, Dongying; Assumpção, Teresa C F; Ribeiro, José M C; Pena, Mirna; Qi, Chen-Feng; Diouf, Ababacar; Moretz, Samuel E; Long, Carole A; Ackerman, Hans C; Pierce, Susan K; Sá-Nunes, Anderson; Waisberg, Michael

    2014-01-01

    The role of intracellular radical oxygen species (ROS) in pathogenesis of cerebral malaria (CM) remains incompletely understood. We undertook testing Tempol--a superoxide dismutase (SOD) mimetic and pleiotropic intracellular antioxidant--in cells relevant to malaria pathogenesis in the context of coagulation and inflammation. Tempol was also tested in a murine model of CM induced by Plasmodium berghei Anka infection. Tempol was found to prevent transcription and functional expression of procoagulant tissue factor in endothelial cells (ECs) stimulated by lipopolysaccharide (LPS). This effect was accompanied by inhibition of IL-6, IL-8, and monocyte chemoattractant protein (MCP-1) production. Tempol also attenuated platelet aggregation and human promyelocytic leukemia HL60 cells oxidative burst. In dendritic cells, Tempol inhibited LPS-induced production of TNF-α, IL-6, and IL-12p70, downregulated expression of co-stimulatory molecules, and prevented antigen-dependent lymphocyte proliferation. Notably, Tempol (20 mg/kg) partially increased the survival of mice with CM. Mechanistically, treated mice had lowered plasma levels of MCP-1, suggesting that Tempol downmodulates EC function and vascular inflammation. Tempol also diminished blood brain barrier permeability associated with CM when started at day 4 post infection but not at day 1, suggesting that ROS production is tightly regulated. Other antioxidants-such as α-phenyl N-tertiary-butyl nitrone (PBN; a spin trap), MnTe-2-PyP and MnTBAP (Mn-phorphyrin), Mitoquinone (MitoQ) and Mitotempo (mitochondrial antioxidants), M30 (an iron chelator), and epigallocatechin gallate (EGCG; polyphenol from green tea) did not improve survival. By contrast, these compounds (except PBN) inhibited Plasmodium falciparum growth in culture with different IC50s. Knockout mice for SOD1 or phagocyte nicotinamide adenine dinucleotide phosphate (NADPH) oxidase (gp91(phox-/-)) or mice treated with inhibitors of SOD (diethyldithiocarbamate

  18. Mucosal reactive oxygen species decrease virulence by disrupting Campylobacter jejuni phosphotyrosine signaling

    PubMed Central

    Corcionivoschi, Nicolae; Alvarez, Luis A.; Sharp, Thomas H.; Strengert, Monika; Alemka, Abofu; Mantell, Judith; Verkade, Paul; Knaus, Ulla G.; Bourke, Billy

    2013-01-01

    Summary Reactive oxygen species (ROS) play key roles in mucosal defense, yet how they are induced and the consequences for pathogens are unclear. We report that ROS generated by epithelial NADPH oxidases (Nox1/Duox2) during Campylobacter jejuni infection impair bacterial capsule formation and virulence by altering bacterial signal transduction. Upon C. jejuni invasion, ROS released from the intestinal mucosa inhibit the bacterial phosphotyrosine network that is regulated by the outer membrane tyrosine kinase Cjtk (Cj1170/OMP50). ROS-mediated Cjtk inactivation results in an overall decrease in the phosphorylation of C. jejuni outer membrane / periplasmic proteins including UDP-GlcNAc/Glc 4-epimerase (Gne), an enzyme required for N-glycosylation and capsule formation. Cjtk positively regulates Gne by phosphorylating an active site tyrosine, while loss of Cjtk or ROS treatment inhibits Gne activity, causing altered polysaccharide synthesis. Thus, epithelial NADPH oxidases are an early antibacterial defense system in the intestinal mucosa that modifies virulence by disrupting bacterial signaling. PMID:22817987

  19. Inhibition and oxygen activation in copper amine oxidases.

    PubMed

    Shepard, Eric M; Dooley, David M

    2015-05-19

    Copper-containing amine oxidases (CuAOs) use both copper and 2,4,5-trihydroxyphenylalanine quinone (TPQ) to catalyze the oxidative deamination of primary amines. The CuAO active site is highly conserved and comprised of TPQ and a mononuclear type II copper center that exhibits five-coordinate, distorted square pyramidal coordination geometry with histidine ligands and equatorially and axially bound water in the oxidized, resting state. The active site is buried within the protein, and CuAOs from various sources display remarkable diversity with respect to the composition of the active site channel and cofactor accessibility. Structural and mechanistic factors that influence substrate preference and inhibitor sensitivity and selectivity have been defined. This Account summarizes the strategies used to design selective CuAO inhibitors based on active site channel characteristics, leading to either enhanced steric fits or the trapping of reactive electrophilic products. These findings provide a framework to support the future development of candidate molecules aimed at minimizing the negative side effects associated with drugs containing amine functionalities. This is vital given the existence of human diamine oxidase and vascular adhesion protein-1, which have distinct amine substrate preferences and are associated with different metabolic processes. Inhibition of these enzymes by antifungal or antiprotozoal agents, as well as classic monoamine oxidase (MAO) inhibitors, may contribute to the adverse side effects associated with drug treatment. These observations provide a rationale for the limited clinical value associated with certain amine-containing pharmaceuticals and emphasize the need for more selective AO inhibitors. This Account also discusses the novel roles of copper and TPQ in the chemistry of O2 activation and substrate oxidation. Reduced CuAOs exist in a redox equilibrium between the Cu(II)-TPQAMQ (aminoquinol) and Cu(I)-TPQSQ (semiquinone). Elucidating

  20. Inhibition of monoamine oxidase isoforms modulates nicotine withdrawal syndrome in the rat.

    PubMed

    Malin, D H; Moon, W D; Goyarzu, P; Barclay, E; Magallanes, N; Vela, A J; Negrete, A P; Mathews, H; Stephens, B; Mills, W R

    2013-10-06

    There have been many reports of monoamine oxidase (MAO) inhibition by non-nicotine ingredients in tobacco smoke, persisting for days after smoking cessation. This study determined the effect of inhibiting MAO and its isoforms on nicotine withdrawal syndrome. Rats were rendered nicotine-dependent by seven days of subcutaneous (s.c.) 9 mg/kg/day infusion of nicotine bitartrate. Twenty-two hours after termination of infusion, they were observed over 20 min for somatically expressed nicotine withdrawal signs. Three hours before observation, rats were injected intraperitoneally (i.p.) with 4 mg/kg each of the MAO A antagonist clorgyline and the MAO B antagonist deprenyl, or with saline alone. A similar experiment was performed with non-dependent, saline-infused rats. Another experiment compared nicotine-dependent rats that received injections of either saline or 4 mg/kg clorgyline alone. A further experiment compared rats receiving either saline or 4 mg/kg deprenyl alone. Combined treatment with both MAO inhibitors markedly and significantly exacerbated somatically expressed nicotine withdrawal signs in nicotine infused rats, while having no significant effects in saline-infused rats. Rats injected s.c. with 4 mg/kg clorgyline alone had significantly more withdrawal signs than saline-injected rats, while deprenyl-injected rats had significantly fewer signs than saline controls. Assays confirmed that clorgyline thoroughly reduced MAO A enzymatic activity and deprenyl thoroughly reduced MAO B activity. The results suggest that inhibition of MAO A may contribute to the intensity of withdrawal syndrome in smoking cessation. © 2013 Elsevier Inc. All rights reserved.

  1. Putting together a plasma membrane NADH oxidase: a tale of three laboratories.

    PubMed

    Löw, Hans; Crane, Frederick L; Morré, D James

    2012-11-01

    The observation that high cellular concentrations of NADH were associated with low adenylate cyclase activity led to a search for the mechanism of the effect. Since cyclase is in the plasma membrane, we considered the membrane might have a site for NADH action, and that NADH might be oxidized at that site. A test for NADH oxidase showed very low activity, which could be increased by adding growth factors. The plasma membrane oxidase was not inhibited by inhibitors of mitochondrial NADH oxidase such as cyanide, rotenone or antimycin. Stimulation of the plasma membrane oxidase by iso-proterenol or triiodothyronine was different from lack of stimulation in endoplasmic reticulum. After 25 years of research, three components of a trans membrane NADH oxidase have been discovered. Flavoprotein NADH coenzyme Q reductases (NADH cytochrome b reductase) on the inside, coenzyme Q in the middle, and a coenzyme Q oxidase on the outside as a terminal oxidase. The external oxidase segment is a copper protein with unique properties in timekeeping, protein disulfide isomerase and endogenous NADH oxidase activity, which affords a mechanism for control of cell growth by the overall NADH oxidase and the remarkable inhibition of oxidase activity and growth of cancer cells by a wide range of anti-tumor drugs. A second trans plasma membrane electron transport system has been found in voltage dependent anion channel (VDAC), which has NADH ferricyanide reductase activity. This activity must be considered in relation to ferricyanide stimulation of growth and increased VDAC antibodies in patients with autism. Copyright © 2012 Elsevier Ltd. All rights reserved.

  2. Rat striatal monoamine oxidase-B inhibition by l-deprenyl and rasagiline: its relationship to 2-phenylethylamine-induced stereotypy and Parkinson's disease.

    PubMed

    Youdim, M B H; Tipton, K F

    2002-03-01

    Rats were injected intraperitoneally with varying doses of l-deprenyl (selegiline) followed 2h later by 30 mg kg(-1) 2-phenylethylamine (PEA), administered in the same way, and the stereotypic behavioural response elicited was assessed. l-Deprenyl alone at doses of up to 5 mg kg(-1) caused no significant behavioural response. Administration of PEA without prior l-deprenyl treatment resulted in only a modest increase in stereotypic behaviour and this was not significantly enhanced by the prior administration 1 mg kg(-1) l-deprenyl. When the administered dose of l-deprenyl was increased to 2.5 or 5 mgkg(-1), however, the stereotypic behavioural response to PEA was greatly potentiated and in the latter case persisted for 60 min. A dose of 2.5 mg kg(-1) l-deprenyl and 1 mg kg(-1) rasagiline was shown to result in over 90% inhibition of the monoamine oxidase (MAO)-B from rat liver and striatum, whereas the inhibition of MAO-A was about 60 and 40% in liver and striatum, respectively. The recovery of MAO-B activity in rat striatum and liver following a single i.p. injection of 5 mg kg(-1) l-deprenyl gave first-order rate constants of 1.80 and 7.15 h(-1), respectively, which corresponded to half-lives of 9.23 and 2.33 days. Similar results were obtained with rasagiline. The corresponding indices of stereotypic response to PEA (30 mg kg(-1); i.p.) during recovery from the single dose of l-deprenyl were initially high, but had started to decline by the third day after l-deprenyl treatment and was not significant after day 4. At that time, less than 20% of the striatal monoamine oxidase-B activity had been regained, whereas the recovery of the liver enzyme was about 65%. These data are discussed in terms of the suggested involvement of PEA potentiation in the anti-parkinsonian actions of l-deprenyl and rasagiline and the duration of the 'wash-out' period used in studies on the effects of l-deprenyl on patients with Parkinson's disease. The longer duration of the recovery of

  3. Seasonal superoxide overproduction and endothelial activation in guinea-pig heart; seasonal oxidative stress in rats and humans.

    PubMed

    Konior, Anna; Klemenska, Emilia; Brudek, Magdalena; Podolecka, Ewa; Czarnowska, Elżbieta; Beręsewicz, Andrzej

    2011-04-01

    Seasonality in endothelial dysfunction and oxidative stress was noted in humans and rats, suggesting it is a common phenomenon of a potential clinical relevance. We aimed at studying (i) seasonal variations in cardiac superoxide (O(2)(-)) production in rodents and in 8-isoprostane urinary excretion in humans, (ii) the mechanism of cardiac O(2)(-) overproduction occurring in late spring/summer months in rodents, (iii) whether this seasonal O(2)(-)-overproduction is associated with a pro-inflammatory endothelial activation, and (iv) how the summer-associated changes compare to those caused by diabetes, a classical cardiovascular risk factor. Langendorff-perfused guinea-pig and rat hearts generated ~100% more O(2)(-), and human subjects excreted 65% more 8-isoprostane in the summer vs. other seasons. Inhibitors of NADPH oxidase, xanthine oxidase, and NO synthase inhibited the seasonal O(2)(-)-overproduction. In the summer vs. other seasons, cardiac NADPH oxidase and xanthine oxidase activity, and protein expression were increased, the endothelial NO synthase and superoxide dismutases were downregulated, and, in guinea-pig hearts, adhesion molecules upregulation and the endothelial glycocalyx destruction associated these changes. In guinea-pig hearts, the summer and a streptozotocin-induced diabetes mediated similar changes, yet, more severe endothelial activation associated the diabetes. These findings suggest that the seasonal oxidative stress is a common phenomenon, associated, at least in guinea-pigs, with the endothelial activation. Nonetheless, its biological meaning (regulatory vs. deleterious) remains unclear. Upregulated NADPH oxidase and xanthine oxidase and uncoupled NO synthase are the sources of the seasonal O(2)(-)-overproduction. Copyright © 2010 Elsevier Ltd. All rights reserved.

  4. The protein inhibitor of nNOS (PIN/DLC1/LC8) binding does not inhibit the NADPH-dependent heme reduction in nNOS, a key step in NO synthesis

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

    Parhad, Swapnil S.; Jaiswal, Deepa; TIFR Centre for Interdisciplinary Sciences, 21 Brundavan Colony, Narsingi, Hyderabad 500075

    The neuronal nitric oxide synthase (nNOS) is an essential enzyme involved in the synthesis of nitric oxide (NO), a potent neurotransmitter. Although previous studies have indicated that the dynein light chain 1 (DLC1) binding to nNOS could inhibit the NO synthesis, the claim is challenged by contradicting reports. Thus, the mechanism of nNOS regulation remained unclear. nNOS has a heme-bearing, Cytochrome P450 core, and the functional enzyme is a dimer. The electron flow from NADPH to Flavin, and finally to the heme of the paired nNOS subunit within a dimer, is facilitated upon calmodulin (CaM) binding. Here, we show thatmore » DLC1 binding to nNOS-CaM complex does not affect the electron transport from the reductase to the oxygenase domain. Therefore, it cannot inhibit the rate of NADPH-dependent heme reduction in nNOS, which results in L-Arginine oxidation. Also, the NO release activity does not decrease with increasing DLC1 concentration in the reaction mix, which further confirmed that DLC1 does not inhibit nNOS activity. These findings suggest that the DLC1 binding may have other implications for the nNOS function in the cell. - Highlights: • The effect of interaction of nNOS with DLC1 has been debatable with contradicting reports in literature. • Purified DLC1 has no effect on electron transport between reductase and oxygenase domain of purified nNOS-CaM. • The NO release activity of nNOS was not altered by DLC1, supporting that DLC1 does not inhibit the enzyme. • These findings suggest that the DLC1 binding may have other implications for the nNOS function in the cell.« less

  5. Ginsenoside Re protects against phencyclidine-induced behavioral changes and mitochondrial dysfunction via interactive modulation of glutathione peroxidase-1 and NADPH oxidase in the dorsolateral cortex of mice.

    PubMed

    Tran, The-Vinh; Shin, Eun-Joo; Dang, Duy-Khanh; Ko, Sung Kwon; Jeong, Ji Hoon; Nah, Seung-Yeol; Jang, Choon-Gon; Lee, Yu Jeung; Toriumi, Kazuya; Nabeshima, Toshitaka; Kim, Hyoung-Chun

    2017-12-01

    We investigated whether ginsenoside Re (Re) modulates phencyclidine (PCP)-induced sociability deficits and recognition memory impairments to extend our recent finding. We examined the role of GPx-1 gene in the pharmacological activity of Re against mitochondrial dysfunction induced by PCP in the dorsolateral cortex of mice. Since mitochondrial oxidative stress activates NADPH oxidase (PHOX), we applied PHOX inhibitor apocynin for evaluating interactive modulation between GPx-1 and PHOX against PCP neurotoxicity. Sociability deficits and recognition memory impairments induced by PCP were more pronounced in GPx-1 knockout (KO) than in wild type (WT) mice. PCP-induced mitochondrial oxidative stress, mitochondrial dysfunction, and membrane translocation of p47phox were more evident in GPx-1 KO than in WT. Re treatment significantly attenuated PCP-induced neurotoxic changes. Re also significantly attenuated PCP-induced sociability deficits and recognition memory impairments. The attenuation by Re was comparable to that by apocynin. The attenuation was more obvious in GPx-1 KO than in WT. Importantly, apocynin did not show any additional positive effects on the neuroprotective activity of Re, indicating that PHOX is a molecular target for therapeutic activity of Re. Our results suggest that Re requires interactive modulation between GPx activity and PHOX (p47phox) to exhibit neuroprotective potentials against PCP insult. Copyright © 2017 Elsevier Ltd. All rights reserved.

  6. A commercial mixture of the brominated flame retardant pentabrominated diphenyl ether (DE-71) induces respiratory burst in human neutrophil granulocytes in vitro.

    PubMed

    Reistad, Trine; Mariussen, Espen

    2005-09-01

    Polybrominated diphenyl ethers (PBDEs) are widely used brominated flame retardants (BFRs), which have become ubiquitous in the environment. This study investigates the effects of the pentabrominated diphenyl ether mixture, DE-71, on human neutrophil granulocytes in vitro. DE-71 enhanced production of reactive oxygen species (ROS) in a concentration-dependent manner measured as lucigenin-amplified chemiluminescence. Octabrominated diphenyl ether (OBDE), decabrominated diphenyl ether (DBDE), and the non-brominated diphenyl ether did not induce ROS formation at the concentrations tested. DPI (4 microM), an inhibitor of the NADPH oxidase completely inhibited DE-71 induced ROS formation, highlighting a role for NADPH oxidase activation. The protein kinase C inhibitor BIM (0.25 microM) and the selective chelator of intracellular calcium, BAPTA-AM (5 microM), also inhibited NADPH oxidase activation, indicating a calcium-dependent activation of PKC. ROS formation was also inhibited by the tyrosine kinase inhibitor tyrphostin (1 microM), the phospholipase C inhibitor ET-18-OCH3 (5 microM), and the phosphatidylinositol-3 kinase inhibitor LY294002 (25 microM). Alterations in intracellular calcium were measured using fura-2/AM, and a significant increase was measured after exposure to DE-71 both with and without extracellular calcium. The tetra brominated compound BDE-47 also enhanced ROS formation in a concentration dependent manner. The combination of DE-71 with the bacteria-derived N-formyl peptide fMLP and PCB153 induced an additive effect in the lucigenin assay. We suggest that tyrosine kinase mediated activation of PI3K could result in enhanced activation of calcium-dependent PKC by enhanced PLC activity, followed by intracellular calcium release leading to ROS formation in neutrophil granulocytes.

  7. Contribution of Monoamine Oxidase Inhibition to Tobacco Dependence: A Review of the Evidence.

    PubMed

    Hogg, Ron C

    2016-05-01

    There is a hypothesis that substances present in, or derived from, tobacco smoke inhibit monoamine oxidase (MAO) in the brains of smokers, reducing the degradation of catecholamine neurotransmitters involved in central reward pathways and acting synergistically with nicotine to increase its addictive effects. The objective of this review was to evaluate the evidence for a role of MAO inhibition by tobacco-derived substances in tobacco dependence. Relevant studies on the effects of tobacco use on MAO levels or activity in humans were identified by electronic searches. The identified data show a clear association between smoking and lower density of MAO-A and MAO-B binding sites in the brains of smokers and strong evidence that MAO is inhibited by a substance or substances in, or derived from, tobacco smoke. There was little evidence to support the hypothesis that low MAO levels/activity is a predictive factor for tobacco use. Substances that inhibit MAO in in vitro assays have been isolated from tobacco leaves and tobacco smoke; however, no single substance has been shown to be absorbed from tobacco smoke and to inhibit MAO in the brains of human smokers. Nevertheless, it is possible that MAO inhibition in smokers could result from additive or synergistic effects of several tobacco-derived substances. MAO inhibition potentiates the reinforcing effects of intravenous nicotine in rodents; however, no data were identified to support the hypothesis that MAO inhibitors in or derived from tobacco or tobacco additives affect tobacco dependence in human smokers. This comprehensive review describes the available evidence for the role of MAO inhibition in tobacco dependence and points the way for further research in this field. In view of the large number of MAO inhibitors identified in tobacco and tobacco smoke, identification of the putative inhibitors responsible for the lower level/activity of MAO in smokers may be impractical. Future studies must address whether the

  8. Spinal sigma-1 receptors activate NADPH oxidase 2 leading to the induction of pain hypersensitivity in mice and mechanical allodynia in neuropathic rats.

    PubMed

    Choi, Sheu-Ran; Roh, Dae-Hyun; Yoon, Seo-Yeon; Kang, Suk-Yun; Moon, Ji-Young; Kwon, Soon-Gu; Choi, Hoon-Seong; Han, Ho-Jae; Beitz, Alvin J; Oh, Seog-Bae; Lee, Jang-Hern

    2013-08-01

    We have recently demonstrated that spinal sigma-1 receptors (Sig-1Rs) mediate pain hypersensitivity in mice and neuropathic pain in rats. In this study, we examine the role of NADPH oxidase 2 (Nox2)-induced reactive oxygen species (ROS) on Sig-1R-induced pain hypersensitivity and the induction of chronic neuropathic pain. Neuropathic pain was produced by chronic constriction injury (CCI) of the right sciatic nerve in rats. Mechanical allodynia and thermal hyperalgesia were evaluated in mice and CCI-rats. Western blotting and dihydroethidium (DHE) staining were performed to assess the changes in Nox2 activation and ROS production in spinal cord, respectively. Direct activation of spinal Sig-1Rs with the Sig-1R agonist, PRE084 induced mechanical allodynia and thermal hyperalgesia, which were dose-dependently attenuated by pretreatment with the ROS scavenger, NAC or the Nox inhibitor, apocynin. PRE084 also induced an increase in Nox2 activation and ROS production, which were attenuated by pretreatment with the Sig-1R antagonist, BD1047 or apocynin. CCI-induced nerve injury produced an increase in Nox2 activation and ROS production in the spinal cord, all of which were attenuated by intrathecal administration with BD1047 during the induction phase of neuropathic pain. Furthermore, administration with BD1047 or apocynin reversed CCI-induced mechanical allodynia during the induction phase, but not the maintenance phase. These findings demonstrate that spinal Sig-1Rs modulate Nox2 activation and ROS production in the spinal cord, and ultimately contribute to the Sig-1R-induced pain hypersensitivity and the peripheral nerve injury-induced induction of chronic neuropathic pain. Copyright © 2013 Elsevier Ltd. All rights reserved.

  9. Characterization of the 1st and 2nd EF-hands of NADPH oxidase 5 by fluorescence, isothermal titration calorimetry, and circular dichroism

    PubMed Central

    2012-01-01

    Background Superoxide generated by non-phagocytic NADPH oxidases (NOXs) is of growing importance for physiology and pathobiology. The calcium binding domain (CaBD) of NOX5 contains four EF-hands, each binding one calcium ion. To better understand the metal binding properties of the 1st and 2nd EF-hands, we characterized the N-terminal half of CaBD (NCaBD) and its calcium-binding knockout mutants. Results The isothermal titration calorimetry measurement for NCaBD reveals that the calcium binding of two EF-hands are loosely associated with each other and can be treated as independent binding events. However, the Ca2+ binding studies on NCaBD(E31Q) and NCaBD(E63Q) showed their binding constants to be 6.5 × 105 and 5.0 × 102 M-1 with ΔHs of -14 and -4 kJ/mol, respectively, suggesting that intrinsic calcium binding for the 1st non-canonical EF-hand is largely enhanced by the binding of Ca2+ to the 2nd canonical EF-hand. The fluorescence quenching and CD spectra support a conformational change upon Ca2+ binding, which changes Trp residues toward a more non-polar and exposed environment and also increases its α-helix secondary structure content. All measurements exclude Mg2+-binding in NCaBD. Conclusions We demonstrated that the 1st non-canonical EF-hand of NOX5 has very weak Ca2+ binding affinity compared with the 2nd canonical EF-hand. Both EF-hands interact with each other in a cooperative manner to enhance their Ca2+ binding affinity. Our characterization reveals that the two EF-hands in the N-terminal NOX5 are Ca2+ specific. Graphical abstract PMID:22490336

  10. Intracellular NADPH Levels Affect the Oligomeric State of the Glucose 6-Phosphate Dehydrogenase

    PubMed Central

    Tramonti, Angela; Lanini, Claudio; Cialfi, Samantha; De Biase, Daniela; Falcone, Claudio

    2012-01-01

    In the yeast Kluyveromyces lactis, glucose 6-phosphate dehydrogenase (G6PDH) is detected as two differently migrating forms on native polyacrylamide gels. The pivotal metabolic role of G6PDH in K. lactis led us to investigate the mechanism controlling the two activities in respiratory and fermentative mutant strains. An extensive analysis of these mutants showed that the NAD+(H)/NADP+(H)-dependent cytosolic alcohol (ADH) and aldehyde (ALD) dehydrogenase balance affects the expression of the G6PDH activity pattern. Under fermentative/ethanol growth conditions, the concomitant activation of ADH and ALD activities led to cytosolic accumulation of NADPH, triggering an alteration in the oligomeric state of the G6PDH caused by displacement/release of the structural NADP+ bound to each subunit of the enzyme. The new oligomeric G6PDH form with faster-migrating properties increases as a consequence of intracellular redox unbalance/NADPH accumulation, which inhibits G6PDH activity in vivo. The appearance of a new G6PDH-specific activity band, following incubation of Saccharomyces cerevisiae and human cellular extracts with NADP+, also suggests that a regulatory mechanism of this activity through NADPH accumulation is highly conserved among eukaryotes. PMID:23064253

  11. A Mycobacterium tuberculosis cytochrome bd oxidase mutant is hypersensitive to bedaquiline.

    PubMed

    Berney, Michael; Hartman, Travis E; Jacobs, William R

    2014-07-15

    The new medicinal compound bedaquiline (BDQ) kills Mycobacterium tuberculosis by inhibiting F1Fo-ATP synthase. BDQ is bacteriostatic for 4 to 7 days and kills relatively slowly compared to other frontline tuberculosis (TB) drugs. Here we show that killing with BDQ can be improved significantly by inhibiting cytochrome bd oxidase, a non-proton-pumping terminal oxidase. BDQ was instantly bactericidal against a cytochrome bd oxidase null mutant of M. tuberculosis, and the rate of killing was increased by more than 50%. We propose that this exclusively bacterial enzyme should be a high-priority target for new drug discovery. Importance: A major drawback of current TB chemotherapy is its long duration. New drug regimens with rapid killing kinetics are desperately needed. Our study demonstrates that inhibition of a nonessential bacterial enzyme greatly improves the efficacy of the latest TB drug bedaquiline and emphasizes that screening for compounds with synergistic killing mechanisms is a promising strategy. Copyright © 2014 Berney et al.

  12. Cellular antioxidant effects of atorvastatin in vitro and in vivo.

    PubMed

    Wassmann, Sven; Laufs, Ulrich; Müller, Kirsten; Konkol, Christian; Ahlbory, Katja; Bäumer, Anselm T; Linz, Wolfgang; Böhm, Michael; Nickenig, Georg

    2002-02-01

    3-Hydroxy-3-methylglutaryl coenzyme A reductase inhibitors (statins) may exert direct effects on vascular cells and beneficially influence endothelial dysfunction. Because reactive oxygen species (ROS) may lead to vascular damage and dysfunction, we investigated the effect of atorvastatin on ROS production and the underlying mechanisms in vitro and in vivo. Cultured rat aortic vascular smooth muscle cells were incubated with 10 micromol/L atorvastatin. Angiotensin II-induced and epidermal growth factor-induced ROS production were significantly reduced by atorvastatin (dichlorofluorescein fluorescence laser microscopy). Atorvastatin downregulated mRNA expression of the NAD(P)H oxidase subunit nox1, whereas p22phox mRNA expression was not significantly altered (reverse transcription-polymerase chain reaction, Northern analysis). Membrane translocation of rac1 GTPase, which is required for the activation of NAD(P)H oxidase, was inhibited by atorvastatin (Western blot). mRNA expression of superoxide dismutase isoforms and glutathione peroxidase was not modified by atorvastatin, whereas catalase expression was upregulated at mRNA and protein levels, resulting in an increased enzymatic activity. Effects of atorvastatin on ROS production and nox1, rac1, and catalase expression were inhibited by L-mevalonate but not by 25-hydroxycholesterol. In addition, spontaneously hypertensive rats were treated with atorvastatin for 30 days. ROS production in aortic segments was significantly reduced in statin-treated rats (lucigenin chemiluminescence). Treatment with atorvastatin reduced vascular mRNA expression of p22phox and nox1 and increased aortic catalase expression. mRNA expression of superoxide dismutases, glutathione peroxidase, and NAD(P)H oxidase subunits gp91phox, p40phox, p47phox, and p67phox remained unchanged. Translocation of rac1 from the cytosol to the cell membrane was also reduced in vivo. Thus, atorvastatin exerts cellular antioxidant effects in cultured rat

  13. Acute intermittent hypoxia induced phrenic long-term facilitation despite increased SOD1 expression in a rat model of ALS

    PubMed Central

    Nichols, Nicole L.; Satriotomo, Irawan; Harrigan, Daniel J.; Mitchell, Gordon S.

    2015-01-01

    Amyotrophic lateral sclerosis (ALS) is a progressive and fatal neurodegenerative disease characterized by motor neuron death. Since most ALS patients succumb to ventilatory failure from loss of respiratory motor neurons, any effective ALS treatment must preserve and/or restore breathing capacity. In rats over-expressing mutated superoxide dismutase-1 (SOD1G93A), the capacity to increase phrenic motor output is decreased at disease end-stage, suggesting imminent ventilatory failure. Acute intermittent hypoxia (AIH) induces phrenic long-term facilitation (pLTF), a form of spinal respiratory motor plasticity with potential to restore phrenic motor output in clinical disorders that compromise breathing. Since pLTF requires NADPH oxidase activity and reactive oxygen species (ROS) formation, it is blocked by NADPH oxidase inhibition and SOD mimetics in normal rats. Thus, we hypothesized that SOD1G93A (mutant; MT) rats do not express AIH-induced pLTF due to over-expression of active mutant superoxide dismutase-1. AIH-induced pLTF and hypoglossal (XII) LTF were assessed in young, pre-symptomatic and end-stage anesthetized MT rats and age-matched wild-type littermates. Contrary to predictions, pLTF and XII LTF were observed in MT rats at all ages; at end-stage, pLTF was actually enhanced. SOD1 levels were elevated in young and pre-symptomatic MT rats, yet superoxide accumulation in putative phrenic motor neurons (assessed with dihydroethidium) was unchanged; however, superoxide accumulation significantly decreased at end-stage. Thus, compensatory mechanisms appear to maintain ROS homoeostasis until late in disease progression, preserving AIH-induced respiratory plasticity. Following intrathecal injections of an NADPH oxidase inhibitor (apocynin; 600µM; 12µL), pLTF was abolished in pre-symptomatic, but not end-stage MT rats, demonstrating that pLTF is NADPH oxidase dependent in pre-symptomatic, but NADPH oxidase independent in end-stage MT rats. Mechanisms preserving

  14. Determination of Monoamine Oxidase A and B Activity in Long-Term Treated Patients With Parkinson Disease.

    PubMed

    Müller, Thomas; Riederer, Peter; Grünblatt, Edna

    Biogenic amines and monoamine oxidase inhibitors influence peripheral monoamine oxidase enzyme activity in chronic levodopa/dopa decarboxylase inhibitor-treated patients with Parkinson disease. Rasagiline is an irreversible inhibitor of monoamine oxidase B. Safinamide blocks this isoenzyme in a reversible fashion. The aim of this study was to determine monoamine oxidase A (plasma) and B (platelets) enzyme activity in long-term levodopa-treated patients without and with additional oral intake of 50- or 100-mg safinamide or 1-mg rasagiline or first-time intake of rasagiline. Monoamine oxidase A enzyme activity did not differ between all groups. Patients on rasagiline or safinamide showed lower monoamine oxidase-B enzyme activity compared with patients without monoamine oxidase B inhibitor intake. No impact of the number of previous oral levodopa intakes was found. Rasagiline and safinamide did not essentially differ in terms of inhibition of monoamine oxidase B despite their different pharmacology regarding reversibility of monoamine oxidase B inhibition. In view of the observed, considerable heterogeneity of enzyme activities, we suggest to determine activities of monoamine oxidase A and B to reduce the risk for tyramine-induced hypertension and the serotonergic syndrome during chronic therapy with rasagiline or safinamide.

  15. BK channels in innate immune functions of neutrophils and macrophages

    PubMed Central

    Essin, Kirill; Gollasch, Maik; Rolle, Susanne; Weissgerber, Patrick; Sausbier, Matthias; Bohn, Erwin; Autenrieth, Ingo B.; Ruth, Peter; Luft, Friedrich C.; Kettritz, Ralph

    2009-01-01

    Oxygen-dependent antimicrobial activity of human polymorphonuclear leukocytes (PMNs) relies on the phagocyte nicotinamide adenine dinucleotide phosphate (NADPH) oxidase to generate oxidants. As the oxidase transfers electrons from NADPH the membrane will depolarize and concomitantly terminate oxidase activity, unless there is charge translocation to compensate. Most experimental data implicate proton channels as the effectors of this charge compensation, although large-conductance Ca2+-activated K+ (BK) channels have been suggested to be essential for normal PMN antimicrobial activity. To test this latter notion, we directly assessed the role of BK channels in phagocyte function, including the NADPH oxidase. PMNs genetically lacking BK channels (BK−/−) had normal intracellular and extracellular NADPH oxidase activity in response to both receptor-independent and phagocytic challenges. Furthermore, NADPH oxidase activity of human PMNs and macrophages was normal after treatment with BK channel inhibitors. Although BK channel inhibitors suppressed endotoxin-mediated tumor necrosis factor-α secretion by bone marrow-derived macrophages (BMDMs), BMDMs of BK−/− and wild-type mice responded identically and exhibited the same ERK, PI3K/Akt, and nuclear factor-κB activation. Based on these data, we conclude that the BK channel is not required for NADPH oxidase activity in PMNs or macrophages or for endotoxin-triggered tumor necrosis factor-α release and signal transduction BMDMs. PMID:19074007

  16. Induction by carrot allelochemicals of insecticide-metabolising enzymes in the southern armyworm (Spodoptera eridania).

    PubMed

    Brattsten, L B; Evans, C K; Bonetti, S; Zalkow, L H

    1984-01-01

    Carrot foliage monoterpenes induce cytochrome P-450 up to 2.9-fold, NADPH cytochrome c (P-450) reductase up to 1.6-fold, NADPH-oxidation up to 3.8-fold, aldrin epoxidation up to 1.5-fold in southern armyworm larval midgut tissues when incorporated in their diet at 0.2% for 3 days. Stigmasterol and ergosterol did not substantially induce microsomal oxidase activities and significantly inhibited GSH S-aryltransferase activity and sulfotransferase activity. Coumarin did not substantially affect microsomal oxidase and sulfotransferase activity but is the most potent inducer of GSH S-aryltransferase activity, increasing this activity 7-fold. None of the chemicals is acutely toxic to the sixth instar larvae or affect the larval weight gain except coumarin which significantly depressed the maximal body weight attained.

  17. Sildenafil citrate and sildenafil nitrate (NCX 911) are potent inhibitors of superoxide formation and gp91phox expression in porcine pulmonary artery endothelial cells

    PubMed Central

    Muzaffar, Saima; Shukla, Nilima; Srivastava, Amit; Angelini, Gianni D; Jeremy, Jamie Y

    2005-01-01

    Acute respiratory distress syndrome (ARDS) is associated with increased superoxide (O2•−) formation in the pulmonary vasculature and negation of the bioavailability of nitric oxide (NO). Since NO inhibits NADPH oxidase expression through a cyclic GMP-mediated mechanism, sildenafil, a type V phosphodiesterase inhibitor, may be therapeutically effective in ARDS through an augmentation of NO-mediated inhibition of NADPH oxidase. Therefore, the effect of sildenafil citrate and NO-donating sildenafil (NCX 911) on O2•− formation and gp91phox (active catalytic subunit of NADPH oxidase) expression was investigated in cultured porcine pulmonary artery endothelial cells (PAECs). PAECs were incubated with 10 nM TXA2 analogue, 9,11-dideoxy-9α,11α-methanoepoxy-prostaglandin F2α (U46619) (±sildenafil or NCX 911), for 16 h and O2•− formation measured spectrophometrically and gp91phox using Western blotting. The role of the NO-cGMP axis was studied using morpholinosydnonimine hydrochloride (SIN-1), the diethylamine/NO complex (DETA-NONOate), the guanylyl cyclase inhibitor, 1H-{1,2,4}oxadiazolo{4,3-a}quinoxalin-1-one (ODQ), and the protein kinase G inhibitor, 8-bromoguanosine-3′,5′-cyclic monophosphorothioate, Rp-isomer (Rp-8-Br-cGMPS). NO release was studied using a fluorescence assay and O2•−–NO interactions by measuring nitrites. After a 16-h incubation with 10 nM U46619, both NCX 911 and sildenafil elicited a concentration-dependent inhibition of O2•− formation and gp91phox expression, NCX 911 being more potent (IC50; 0.26 nM) than sildenafil citrate (IC50; 1.85 nM). These inhibitory effects were reversed by 1 μM ODQ and 10 μM Rp-8-Br-cGMPS. NCX 911 stimulated the formation of cGMP in PAECs and generated NO in a cell-free system to a greater degree than sildenafil citrate. The inhibitory effect of sildenafil was augmented by 1 μM SIN-1 and blocked partially by the eNOS inhibitor 10 μM N5-(1-iminoethyl)-ornithine (L

  18. Quantum chemical modeling of the inhibition mechanism of monoamine oxidase by oxazolidinone and analogous heterocyclic compounds.

    PubMed

    Erdem, Safiye Sağ; Özpınar, Gül Altınbaş; Boz, Ümüt

    2014-02-01

    Monoamine oxidase (MAO, EC 1.4.3.4) is responsible from the oxidation of a variety of amine neurotransmitters. MAO inhibitors are used for the treatment of depression or Parkinson's disease. They also inhibit the catabolism of dietary amines. According to one hypothesis, inactivation results from the formation of a covalent adduct to a cysteine residue in the enzyme. If the adduct is stable enough, the enzyme is inhibited for a long time. After a while, enzyme can turn to its active form as a result of adduct breakdown by β-elimination. In this study, the proposed inactivation mechanism was modeled and tested by quantum chemical calculations. Eight heterocyclic methylthioamine derivatives were selected to represent the proposed covalent adducts. Activation energies related to their β-elimination reactions were calculated using ab initio and density functional theory methods. Calculated activation energies were in good agreement with the relative stabilities of the hypothetical adducts predicted in the literature by enzyme inactivation measurements.

  19. Cancer-associated Isocitrate Dehydrogenase Mutations Inactivate NADPH-dependent Reductive Carboxylation*

    PubMed Central

    Leonardi, Roberta; Subramanian, Chitra; Jackowski, Suzanne; Rock, Charles O.

    2012-01-01

    Isocitrate dehydrogenase (IDH) is a reversible enzyme that catalyzes the NADP+-dependent oxidative decarboxylation of isocitrate (ICT) to α-ketoglutarate (αKG) and the NADPH/CO2-dependent reductive carboxylation of αKG to ICT. Reductive carboxylation by IDH1 was potently inhibited by NADP+ and, to a lesser extent, by ICT. IDH1 and IDH2 with cancer-associated mutations at the active site arginines were unable to carry out the reductive carboxylation of αKG. These mutants were also defective in ICT decarboxylation and converted αKG to 2-hydroxyglutarate using NADPH. These mutant proteins were thus defective in both of the normal reactions of IDH. Biochemical analysis of heterodimers between wild-type and mutant IDH1 subunits showed that the mutant subunit did not inactivate reductive carboxylation by the wild-type subunit. Cells expressing the mutant IDH are thus deficient in their capacity for reductive carboxylation and may be compromised in their ability to produce acetyl-CoA under hypoxia or when mitochondrial function is otherwise impaired. PMID:22442146

  20. Molecular characterization of the NADPH oxidase complex in the ergot fungus Claviceps purpurea: CpNox2 and CpPls1 are important for a balanced host-pathogen interaction.

    PubMed

    Schürmann, Janine; Buttermann, Dagmar; Herrmann, Andrea; Giesbert, Sabine; Tudzynski, Paul

    2013-10-01

    Reactive oxygen species producing NADPH oxidase (Nox) complexes are involved in defense reactions in animals and plants while they trigger infection-related processes in pathogenic fungi. Knowledge about the composition and localization of these complexes in fungi is limited; potential components identified thus far include two to three catalytical subunits, a regulatory subunit (NoxR), the GTPase Rac, the scaffold protein Bem1, and a tetraspanin-like membrane protein (Pls1). We showed that, in the biotrophic grass-pathogen Claviceps purpurea, the catalytical subunit CpNox1 is important for infection. Here, we present identification of major Nox complex partners and a functional analysis of CpNox2 and the tetraspanin CpPls1. We show that, as in other fungi, Nox complexes are important for formation of sclerotia; CpRac is, indeed, a complex partner because it interacts with CpNoxR, and CpNox1/2 and CpPls1 are associated with the endoplasmatic reticulum. However, unlike in all other fungi, Δcppls1 is more similar to Δcpnox1 than to Δcpnox2, and CpNox2 is not essential for infection. In contrast, Δcpnox2 shows even more pronounced disease symptoms, indicating that Cpnox2 controls the infection process and moderates damage to the host. These data confirm that fungal Nox complexes have acquired specific functions dependent of the lifestyle of the pathogen.

  1. Cytotoxicity of polyamines to Amoeba proteus: role of polyamine oxidase.

    PubMed

    Schenkel, E; Dubois, J G; Helson-Cambier, M; Hanocq, M

    1996-02-01

    It has been shown that oxidation of polyamines by polyamine oxidases can produce toxic compounds (H2O2, aldehydes, ammonia) and that the polyamine oxidase-polyamine system is implicated, in vitro, in the death of several parasites. Using Amoeba proteus as an in vitro model, we studied the cytotoxicity to these cells of spermine, spermidine, their acetyl derivatives, and their hypothetical precursors. Spermine and N1-acetylspermine were more toxic than emetine, an amoebicidal reference drug. Spermine presented a short-term toxicity, but a 48-h contact time was necessary for the high toxicity of spermidine. The uptake by Amoeba cells of the different polyamines tested was demonstrated. On the other hand, a high polyamine oxidase activity was identified in Amoeba proteus crude extract. Spermine (theoretical 100%) and N1-acetylspermine (64%) were the best substrates at pH 9.5, while spermidine, its acetyl derivatives, and putrescine were very poorly oxidized by this enzyme (3-20%). Spermine oxidase activity was inhibited by phenylhydrazine (nil) and isoniazid (approximately 50%). Mepacrine did not inhibit the enzyme activity at pH 8. Neither monoamine nor diamine oxidase activity (approximately 10%) was found. It must be emphasized that spermine, the best enzyme substrate, is the most toxic polyamine. This finding suggests that knowledge of polyamine oxidase specificity can be used to modulate the cytotoxicity of polyamine derivatives. Amoeba proteus was revealed as a simple model for investigation of the connection between cytotoxicity and enzyme activity.

  2. Gene Expression Patterns during Light and Dark Infection of Prochlorococcus by Cyanophage

    PubMed Central

    Chisholm, Sallie W.

    2016-01-01

    Cyanophage infecting the marine cyanobacteria Prochlorococcus and Synechococcus require light and host photosystem activity for optimal reproduction. Many cyanophages encode multiple photosynthetic electron transport (PET) proteins, which are presumed to maintain electron flow and produce ATP and NADPH for nucleotide biosynthesis and phage genome replication. However, evidence suggests phage augment NADPH production via the pentose phosphate pathway (PPP), thus calling into question the need for NADPH production by PET. Genes implicated in cyclic PET have since been identified in cyanophage genomes. It remains an open question which mode of PET, cyclic or linear, predominates in infected cyanobacteria, and thus whether the balance is towards producing ATP or NADPH. We sequenced transcriptomes of a cyanophage (P-HM2) and its host (Prochlorococcus MED4) throughout infection in the light or in the dark, and analyzed these data in the context of phage replication and metabolite measurements. Infection was robust in the light, but phage were not produced in the dark. Host gene transcripts encoding high-light inducible proteins and two terminal oxidases (plastoquinol terminal oxidase and cytochrome c oxidase)—implicated in protecting the photosynthetic membrane from light stress—were the most enriched in light but not dark infection. Among the most diminished transcripts in both light and dark infection was ferredoxin–NADP+ reductase (FNR), which uses the electron acceptor NADP+ to generate NADPH in linear photosynthesis. The phage gene for CP12, which putatively inhibits the Calvin cycle enzyme that receives NADPH from FNR, was highly expressed in light infection. Therefore, both PET production of NADPH and its consumption by carbon fixation are putatively repressed during phage infection in light. Transcriptomic evidence is thus consistent with cyclic photophosphorylation using oxygen as the terminal electron acceptor as the dominant mode of PET under infection

  3. The xanthine oxidase inhibitor Febuxostat reduces tissue uric acid content and inhibits injury-induced inflammation in the liver and lung

    PubMed Central

    Kataoka, Hiroshi; Yang, Ke; Rock, Kenneth L.

    2014-01-01

    Necrotic cell death in vivo induces a robust neutrophilic inflammatory response and the resulting inflammation can cause further tissue damage and disease. Dying cells induce this inflammation by releasing pro-inflammatory intracellular components, one of which is uric acid. Cells contain high levels of intracellular uric acid, which is produced when purines are oxidized by the enzyme xanthine oxidase. Here we test whether a non-nucleoside xanthine oxidase inhibitor, Febuxostat (FBX), can reduce intracellular uric acid levels and inhibit cell death-induced inflammation in two different murine tissue injury models; acid-induced acute lung injury and acetaminophen liver injury. Infiltration of inflammatory cells induced by acid injection into lungs or peritoneal administration of acetaminophen was evaluated by quantification with flow cytometry and tissue myeloperoxidase activity in the presence or absence of FBX treatment. Uric acid levels in serum and tissue were measured before giving the stimuli and during inflammation. The impact of FBX treatment on the peritoneal inflammation caused by the microbial stimulus, zymosan, was also analyzed to see whether FBX had a broad anti-inflammatory effect. We found that FBX reduced uric acid levels in acid-injured lung tissue and inhibited acute pulmonary inflammation triggered by lung injury. Similarly, FBX reduced uric acid levels in the liver and inhibited inflammation in response to acetaminophen-induced hepatic injury. In contrast, FBX did not reduce inflammation to zymosan, and therefore is not acting as a general anti-inflammatory agent. These results point to the potential of using agents like FBX to treat cell death-induced inflammation. PMID:25449036

  4. A Two-component NADPH Oxidase (NOX)-like System in Bacteria Is Involved in the Electron Transfer Chain to the Methionine Sulfoxide Reductase MsrP*

    PubMed Central

    Juillan-Binard, Céline; Picciocchi, Antoine; Andrieu, Jean-Pierre; Petit-Hartlein, Isabelle; Caux-Thang, Christelle; Vivès, Corinne; Nivière, Vincent

    2017-01-01

    MsrPQ is a newly identified methionine sulfoxide reductase system found in bacteria, which appears to be specifically involved in the repair of periplasmic proteins oxidized by hypochlorous acid. It involves two proteins: a periplasmic one, MsrP, previously named YedY, carrying out the Msr activity, and MsrQ, an integral b-type heme membrane-spanning protein, which acts as the specific electron donor to MsrP. MsrQ, previously named YedZ, was mainly characterized by bioinformatics as a member of the FRD superfamily of heme-containing membrane proteins, which include the NADPH oxidase proteins (NOX/DUOX). Here we report a detailed biochemical characterization of the MsrQ protein from Escherichia coli. We optimized conditions for the overexpression and membrane solubilization of an MsrQ-GFP fusion and set up a purification scheme allowing the production of pure MsrQ. Combining UV-visible spectroscopy, heme quantification, and site-directed mutagenesis of histidine residues, we demonstrated that MsrQ is able to bind two b-type hemes through the histidine residues conserved between the MsrQ and NOX protein families. In addition, we identify the E. coli flavin reductase Fre, which is related to the dehydrogenase domain of eukaryotic NOX enzymes, as an efficient cytosolic electron donor to the MsrQ heme moieties. Cross-linking experiments as well as surface Plasmon resonance showed that Fre interacts with MsrQ to form a specific complex. Taken together, these data support the identification of the first prokaryotic two-component protein system related to the eukaryotic NOX family and involved in the reduction of periplasmic oxidized proteins. PMID:28028176

  5. Reactive oxygen species produced by NADPH oxidase and mitochondrial dysfunction in lung after an acute exposure to Residual Oil Fly Ashes

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

    Magnani, Natalia D.; Marchini, Timoteo; Vanasco, Virginia

    2013-07-01

    Reactive O{sub 2} species production triggered by particulate matter (PM) exposure is able to initiate oxidative damage mechanisms, which are postulated as responsible for increased morbidity along with the aggravation of respiratory diseases. The aim of this work was to quantitatively analyse the major sources of reactive O{sub 2} species involved in lung O{sub 2} metabolism after an acute exposure to Residual Oil Fly Ashes (ROFAs). Mice were intranasally instilled with a ROFA suspension (1.0 mg/kg body weight), and lung samples were analysed 1 h after instillation. Tissue O{sub 2} consumption and NADPH oxidase (Nox) activity were evaluated in tissuemore » homogenates. Mitochondrial respiration, respiratory chain complexes activity, H{sub 2}O{sub 2} and ATP production rates, mitochondrial membrane potential and oxidative damage markers were assessed in isolated mitochondria. ROFA exposure was found to be associated with 61% increased tissue O{sub 2} consumption, a 30% increase in Nox activity, a 33% increased state 3 mitochondrial O{sub 2} consumption and a mitochondrial complex II activity increased by 25%. During mitochondrial active respiration, mitochondrial depolarization and a 53% decreased ATP production rate were observed. Neither changes in H{sub 2}O{sub 2} production rate, nor oxidative damage in isolated mitochondria were observed after the instillation. After an acute ROFA exposure, increased tissue O{sub 2} consumption may account for an augmented Nox activity, causing an increased O{sub 2}{sup ·−} production. The mitochondrial function modifications found may prevent oxidative damage within the organelle. These findings provide new insights to the understanding of the mechanisms involving reactive O{sub 2} species production in the lung triggered by ROFA exposure. - Highlights: • Exposure to ROFA alters the oxidative metabolism in mice lung. • The augmented Nox activity contributes to the high tissue O{sub 2} consumption. • Exposure to

  6. Recurrent/moderate hypoglycemia induces hippocampal dendritic injury, microglial activation, and cognitive impairment in diabetic rats

    PubMed Central

    2012-01-01

    Background Recurrent/moderate (R/M) hypoglycemia is common in type 1 diabetes. Although mild or moderate hypoglycemia is not life-threatening, if recurrent, it may cause cognitive impairment. In the present study, we sought to determine whether R/M hypoglycemia leads to neuronal death, dendritic injury, or cognitive impairment. Methods The experiments were conducted in normal and in diabetic rats. Rats were subjected to moderate hypoglycemia by insulin without anesthesia. Oxidative stress was evaluated by 4-Hydroxy-2-nonenal immunostaining and neuronal death was determined by Fluoro-Jade B staining 7 days after R/M hypoglycemia. To test whether oxidative injury caused by NADPH oxidase activation, an NADPH oxidase inhibitor, apocynin, was used. Cognitive function was assessed by Barnes maze and open field tests at 6 weeks after R/M hypoglycemia. Results The present study found that oxidative injury was detected in the dendritic area of the hippocampus after R/M hypoglycemia. Sparse neuronal death was found in the cortex, but no neuronal death was detected in the hippocampus. Significant cognitive impairment and thinning of the CA1 dendritic region was detected 6 weeks after hypoglycemia. Oxidative injury, cognitive impairment, and hippocampal thinning after R/M hypoglycemia were more severe in diabetic rats than in non-diabetic rats. Oxidative damage in the hippocampal CA1 dendritic area and microglial activation were reduced by the NADPH oxidase inhibitor, apocynin. Conclusion The present study suggests that oxidative injury of the hippocampal CA1 dendritic region by R/M hypoglycemia is associated with chronic cognitive impairment in diabetic patients. The present study further suggests that NADPH oxidase inhibition may prevent R/M hypoglycemia-induced hippocampal dendritic injury. PMID:22830525

  7. gp-91 mediates histone deacetylase inhibition-induced cardioprotection

    PubMed Central

    Zhao, Ting C; Zhang, Ling X; Cheng, Guangmao; Liu, Jun T

    2010-01-01

    We have recently shown that the inhibition of histone deacetylases (HDAC) protects the heart against ischemia and reperfusion (I/R) injury. The mechanism by which HDAC inhibition induces cardioprotection remains unknown. We sought to investigate whether the genetic disruption of gp-91, a subunit of NADPH-oxidase, would mitigate cardioprotection of HDAC inhibition. Wild-type and gp-91−/− mice were treated with a potent inhibitor of HDACs, trichostatin A (TSA, 0.1mg/kg, i.p.). Twenty-four hours later, the perfused hearts were subjected to 30 min of ischemia and 30 min of reperfusion. HDAC inhibition in wild-type mice produced marked improvements in ventricular functional recovery and the reduction of infarct size. TSA-induced cardioprotection was eliminated with genetic deletion of gp91. Notably, Western blot and immunostaining displayed a significant increase in gp-91 in myocardium following HDAC inhibition, which resulted in a mildly subsequent increase in the production of reactive oxygen species (ROS). The pretreatment of H9c2 cardiomyoblasts with TSA (50 nmol/L) decreased cell necrosis and increased viability in response to simulated ischemia (SI), which was abrogated by the transfection of cells with gp-91 siRNA, but not by scrambled siRNA. Furthermore, treatment of PLB-985 gp91+/+cells with TSA increased the resistance to SI, which also diminished with genetic disruption of gp91 in gp91phox-deficient PLB-985 cells. TSA treatment inhibited the increased active caspase-3 in H9c2 cardiomyoblasts and PLB-985 gp91+/+cells exposed to SI, which were prevented by knockdown of gp-91 by siRNA. These results suggest that a cascade consisting of gp-91 and HDAC inhibition plays an essential role in orchestrating the cardioprotective effect. PMID:20433879

  8. The dehydrogenase region of the NADPH oxidase component Nox2 acts as a protein disulfide isomerase (PDI) resembling PDIA3 with a role in the binding of the activator protein p67phox

    PubMed Central

    Bechor, Edna; Dahan, Iris; Fradin, Tanya; Berdichevsky, Yevgeny; Zahavi, Anat; Federman Gross, Aya; Rafalowski, Meirav; Pick, Edgar

    2015-01-01

    The superoxide (O·−2)-generating NADPH oxidase of phagocytes consists of a membrane component, cytochrome b558 (a heterodimer of Nox2 and p22phox), and four cytosolic components, p47phox, p67phox, p40phox, and Rac. The catalytic component, responsible for O·−2 generation, is Nox2. It is activated by the interaction of the dehydrogenase region (DHR) of Nox2 with the cytosolic components, principally with p67phox. Using a peptide-protein binding assay, we found that Nox2 peptides containing a 369CysGlyCys371 triad (CGC) bound p67phox with high affinity, dependent upon the establishment of a disulfide bond between the two cysteines. Serially truncated recombinant Nox2 DHR proteins bound p67phox only when they comprised the CGC triad. CGC resembles the catalytic motif (CGHC) of protein disulfide isomerases (PDIs). This led to the hypothesis that Nox2 establishes disulfide bonds with p67phox via a thiol-dilsulfide exchange reaction and, thus, functions as a PDI. Evidence for this was provided by the following: (1) Recombinant Nox2 protein, which contained the CGC triad, exhibited PDI-like disulfide reductase activity; (2) Truncation of Nox2 C-terminal to the CGC triad or mutating C369 and C371 to R, resulted in loss of PDI activity; (3) Comparison of the sequence of the DHR of Nox2 with PDI family members revealed three small regions of homology with PDIA3; (4) Two monoclonal anti-Nox2 antibodies, with epitopes corresponding to regions of Nox2/PDIA3 homology, reacted with PDIA3 but not with PDIA1; (5) A polyclonal anti-PDIA3 (but not an anti-PDIA1) antibody reacted with Nox2; (6) p67phox, in which all cysteines were mutated to serines, lost its ability to bind to a Nox2 peptide containing the CGC triad and had an impaired capacity to support oxidase activity in vitro. We propose a model of oxidase assembly in which binding of p67phox to Nox2 via disulfide bonds, by virtue of the intrinsic PDI activity of Nox2, stabilizes the primary interaction between the two

  9. The dehydrogenase region of the NADPH oxidase component Nox2 acts as a protein disulfide isomerase (PDI) resembling PDIA3 with a role in the binding of the activator protein p67phox

    NASA Astrophysics Data System (ADS)

    Bechor, Edna; Dahan, Iris; Fradin, Tanya; Berdichevsky, Yevgeny; Zahavi, Anat; Rafalowski, Meirav; Federman-Gross, Aya; Pick, Edgar

    2015-02-01

    The superoxide (O2.-)-generating NADPH oxidase of phagocytes consists of a membrane component, cytochrome b558 (a heterodimer of Nox2 and p22phox), and four cytosolic components, p47phox, p67phox, p40phox, and Rac. The catalytic component, responsible for O2.- generation, is Nox2. It is activated by the interaction of the dehydrogenase region (DHR) of Nox2 with the cytosolic components, principally with p67phox. Using a peptide-protein binding assay, we found that Nox2 peptides containing a 369CysGlyCys371 triad (CGC) bound p67phox with high affinity, dependent upon the establishment of a disulfide bond between the two cysteines. Serially truncated recombinant Nox2 DHR proteins bound p67phox only when they comprised the CGC triad. CGC resembles the catalytic motif (CGHC) of protein disulfide isomerases (PDIs). This led to the hypothesis that Nox2 establishes disulfide bonds with p67phox via a thiol-dilsulfide exchange reaction and, thus, functions as a PDI. Evidence for this was provided by the following: 1. Recombinant Nox2 protein, which contained the CGC triad, exhibited PDI-like disulfide reductase activity; 2. Truncation of Nox2 C-terminal to the CGC triad or mutating C369 and C371 to R, resulted in loss of PDI activity; 3. Comparison of the sequence of the DHR of Nox2 with PDI family members revealed three small regions of homology with PDIA3; 4. Two monoclonal anti-Nox2 antibodies, with epitopes corresponding to regions of Nox2/PDIA3 homology, reacted with PDIA3 but not with PDIA1; 5. A polyclonal anti-PDIA3 (but not an anti-PDIA1) antibody reacted with Nox2; 6. p67phox, in which all cysteines were mutated to serines, lost its ability to bind to a Nox2 peptide containing the CGC triad and had an impaired capacity to support oxidase activity in vitro. We propose a model of oxidase assembly in which binding of p67phox to Nox2 via disulfide bonds, by virtue of the intrinsic PDI activity of Nox2, stabilizes the primary interaction between the two components.

  10. Assessment of Enzyme Inhibition: A Review with Examples from the Development of Monoamine Oxidase and Cholinesterase Inhibitory Drugs.

    PubMed

    Ramsay, Rona R; Tipton, Keith F

    2017-07-15

    The actions of many drugs involve enzyme inhibition. This is exemplified by the inhibitors of monoamine oxidases (MAO) and the cholinsterases (ChE) that have been used for several pharmacological purposes. This review describes key principles and approaches for the reliable determination of enzyme activities and inhibition as well as some of the methods that are in current use for such studies with these two enzymes. Their applicability and potential pitfalls arising from their inappropriate use are discussed. Since inhibitor potency is frequently assessed in terms of the quantity necessary to give 50% inhibition (the IC 50 value), the relationships between this and the mode of inhibition is also considered, in terms of the misleading information that it may provide. Incorporation of more than one functionality into the same molecule to give a multi-target-directed ligands (MTDLs) requires careful assessment to ensure that the specific target effects are not significantly altered and that the kinetic behavior remains as favourable with the MTDL as it does with the individual components. Such factors will be considered in terms of recently developed MTDLs that combine MAO and ChE inhibitory functions.

  11. Cluster Differentiating 36 (CD36) Deficiency Attenuates Obesity-Associated Oxidative Stress in the Heart.

    PubMed

    Gharib, Mohamed; Tao, Huan; Fungwe, Thomas V; Hajri, Tahar

    2016-01-01

    Obesity is often associated with a state of oxidative stress and increased lipid deposition in the heart. More importantly, obesity increases lipid influx into the heart and induces excessive production of reactive oxygen species (ROS) leading to cell toxicity and metabolic dysfunction. Cluster differentiating 36 (CD36) protein is highly expressed in the heart and regulates lipid utilization but its role in obesity-associated oxidative stress is still not clear. The aim of this study was to determine the impact of CD36 deficiency on cardiac steatosis, oxidative stress and lipotoxicity associated with obesity. Studies were conducted in control (Lean), obese leptin-deficient (Lepob/ob) and leptin-CD36 double null (Lepob/obCD36-/-) mice. Compared to lean mice, cardiac steatosis, and fatty acid (FA) uptake and oxidation were increased in Lepob/ob mice, while glucose uptake and oxidation was reduced. Moreover, insulin resistance, oxidative stress markers and NADPH oxidase-dependent ROS production were markedly enhanced. This was associated with the induction of NADPH oxidase expression, and increased membrane-associated p47phox, p67phox and protein kinase C. Silencing CD36 in Lepob/ob mice prevented cardiac steatosis, increased insulin sensitivity and glucose utilization, but reduced FA uptake and oxidation. Moreover, CD36 deficiency reduced NADPH oxidase activity and decreased NADPH oxidase-dependent ROS production. In isolated cardiomyocytes, CD36 deficiency reduced palmitate-induced ROS production and normalized NADPH oxidase activity. CD36 deficiency prevented obesity-associated cardiac steatosis and insulin resistance, and reduced NADPH oxidase-dependent ROS production. The study demonstrates that CD36 regulates NADPH oxidase activity and mediates FA-induced oxidative stress.

  12. Protectin DX, a double lipoxygenase product of DHA, inhibits both ROS production in human neutrophils and cyclooxygenase activities

    PubMed Central

    Liu, Miao; Boussetta, Tarek; Makni-Maalej, Karama; Fay, Michèle; Driss, Fathi; El-Benna, Jamel; Lagarde, Michel; Guichardant, Michel

    2014-01-01

    Neutrophils play a major role in inflammation by releasing large amounts of reactive oxygen species (ROS) produced by NADPH oxidase (NOX) and myeloperoxidase (MPO). This ROS overproduction is mediated by phosphorylation of the NOX subunits with an uncontrolled manner. Therefore, targeting neutrophil subunits would represent a promising strategy to moderate NOX activity, lower ROS, and other inflammatory agents, such as cytokines and leukotrienes, produced by neutrophils. For this purpose, we investigated the effects of protectin DX (PDX) - a docosahexaenoic acid (DHA) di-hydroxylated product which inhibits blood platelet aggregation - on neutrophil activation in vitro. We found that PDX decreases ROS production, inhibits NOX activation and MPO release from neutrophils. We also confirm, that PDX is an anti-aggregatory and anti-inflammatory agent by inhibiting both cyclooxygenase-1 and -2 (COX-1 and COX-2, E.C. 1.14.99.1) as well as COX-2 in lipopolysaccharides (LPS)-treated human neutrophils. However, PDX has no effect on the 5-lipoxygenase pathway that produces the chemotactic agent leukotriene B4 (LTB4). Taken together, our results suggest that PDX could be a protective agent against neutrophil invasion in chronic inflammatory diseases. PMID:24254970

  13. Molecular Insights into Human Monoamine Oxidase B Inhibition by the Glitazone Antidiabetes Drugs

    PubMed Central

    2011-01-01

    The widely employed antidiabetic drug pioglitazone (Actos) is shown to be a specific and reversible inhibitor of human monoamine oxidase B (MAO B). The crystal structure of the enzyme–inhibitor complex shows that the R-enantiomer is bound with the thiazolidinedione ring near the flavin. The molecule occupies both substrate and entrance cavities of the active site, establishing noncovalent interactions with the surrounding amino acids. These binding properties differentiate pioglitazone from the clinically used MAO inhibitors, which act through covalent inhibition mechanisms and do not exhibit a high degree of MAO A versus B selectivity. Rosiglitazone (Avandia) and troglitazone, other members of the glitazone class, are less selective in that they are weaker inhibitors of both MAO A and MAO B. These results suggest that pioglitazone may have utility as a “repurposed” neuroprotectant drug in retarding the progression of disease in Parkinson's patients. They also provide new insights for the development of reversible isoenzyme-specific MAO inhibitors. PMID:22282722

  14. Inhibition of monoamine oxidase by moclobemide: effects on monoamine metabolism and secretion of anterior pituitary hormones and cortisol in healthy volunteers.

    PubMed Central

    Koulu, M; Scheinin, M; Kaarttinen, A; Kallio, J; Pyykkö, K; Vuorinen, J; Zimmer, R H

    1989-01-01

    1. Single oral doses (100, 200 and 300 mg) of moclobemide, a reversible inhibitor of monoamine oxidase (MAO) with predominant effects on the A-type of the enzyme, were administered to eight young, healthy male volunteers in a double-blind, random-order, placebo-controlled study. The investigation was thereafter continued in an open fashion by administering a single 10 mg dose of the MAO-B inhibitor deprenyl to the same subjects. 2. Deamination of catecholamines was powerfully and dose-dependently inhibited by moclobemide, as evidenced by up to 40% decreases in the urinary excretion of deaminated catecholamine metabolites, corresponding increases in the excretion of non-deaminated, methylated metabolites, and up to 79% average decreases in the plasma concentration of 3,4-dihydroxyphenylglycol (DHPG), a deaminated metabolite of noradrenaline (NA), and up to 75% average decreases in the plasma concentrations of 3,4-dihydroxyphenylacetic acid (DOPAC), a deaminated metabolite of dopamine. The urinary excretion of 5-hydroxyindoleacetic acid (5-HIAA) was only slightly reduced. In contrast, deprenyl, in a dose which almost totally inhibited MAO-B activity in blood platelets, did not appreciably affect the plasma concentrations of DHPG or DOPAC. 3. Due to the rapid, reversible, dose-dependent and MAO-A specific effect of moclobemide on plasma concentrations of DHPG, it is suggested that DHPG in plasma may be a useful indicator of the magnitude and duration of MAO-A inhibition in man. 4. Sympatho-adrenal function at rest was not significantly altered by moclobemide, as judged by unchanged plasma catecholamine concentrations and stable blood pressure and heart rate recordings. 5. Monoamine oxidase type B activity in blood platelets was slightly (less than 30%) and transiently inhibited after moclobemide. 6. The secretion of prolactin was dose-dependently stimulated by moclobemide, whereas the plasma concentrations of growth hormone (hGH) and cortisol remained unchanged. PMID

  15. Regulation of the nitric oxide oxidase activity of myeloperoxidase by pharmacological agents.

    PubMed

    Maiocchi, Sophie L; Morris, Jonathan C; Rees, Martin D; Thomas, Shane R

    2017-07-01

    The leukocyte-derived heme enzyme myeloperoxidase (MPO) is released extracellularly during inflammation and impairs nitric oxide (NO) bioavailability by directly oxidizing NO or producing NO-consuming substrate radicals. Here, structurally diverse pharmacological agents with activities as MPO substrates/inhibitors or antioxidants were screened for their effects on MPO NO oxidase activity in human plasma and physiological model systems containing endogenous MPO substrates/antioxidants (tyrosine, urate, ascorbate). Hydrazide-based irreversible/reversible MPO inhibitors (4-ABAH, isoniazid) or the sickle cell anaemia drug, hydroxyurea, all promoted MPO NO oxidase activity. This involved the capacity of NO to antagonize MPO inhibition by hydrazide-derived radicals and/or the ability of drug-derived radicals to stimulate MPO turnover thereby increasing NO consumption by MPO redox intermediates or NO-consuming radicals. In contrast, the mechanism-based irreversible MPO inhibitor 2-thioxanthine, potently inhibited MPO turnover and NO consumption. Although the phenolics acetaminophen and resveratrol initially increased MPO turnover and NO consumption, they limited the overall extent of NO loss by rapidly depleting H 2 O 2 and promoting the formation of ascorbyl radicals, which inefficiently consume NO. The vitamin E analogue trolox inhibited MPO NO oxidase activity in ascorbate-depleted fluids by scavenging NO-consuming tyrosyl and urate radicals. Tempol and related nitroxides decreased NO consumption in ascorbate-replete fluids by scavenging MPO-derived ascorbyl radicals. Indoles or apocynin yielded marginal effects. Kinetic analyses rationalized differences in drug activities and identified criteria for the improved inhibition of MPO NO oxidase activity. This study reveals that widely used agents have important implications for MPO NO oxidase activity under physiological conditions, highlighting new pharmacological strategies for preserving NO bioavailability during

  16. Purification and Characterization of Two Distinct NAD(P)H Dehydrogenases from Onion (Allium cepa L.) Root Plasma Membrane.

    PubMed Central

    Serrano, A.; Cordoba, F.; Gonzalez-Reyes, J. A.; Navas, P.; Villalba, J. M.

    1994-01-01

    Highly purified plasma membrane fractions were obtained from onion (Allium cepa L.) roots and used as a source for purification of redox proteins. Plasma membranes solubilized with Triton X-100 contained two distinct polypeptides showing NAD(P)H-dependent dehydrogenase activities. Dehydrogenase I was purified by gel filtration in Sephacryl S-300 HR, ion-exchange chromatography in DEAE-Sepharose CL-6B, and dye-ligand affinity chromatography in Blue-Sepharose CL-6B after biospecific elution with NADH. Dehydrogenase I consisted of a single polypeptide of about 27 kD and an isoelectric point of about 6. Dehydrogenase II was purified from the DEAE-unbound fraction by chromatography in Blue-Sepharose CL-6B and affinity elution with NADH. Dehydrogenase II consisted of a single polypeptide of about 31 kD and an isoelectric point of about 8. Purified dehydrogenase I oxidized both NADPH and NADH, although higher rates of electron transfer were obtained with NADPH. Maximal activity was achieved with NADPH as donor and juglone or coenzyme Q as acceptor. Dehydrogenase II was specific for NADH and exhibited maximal activity with ferricyanide. Optimal pH for both dehydrogenases was about 6. Dehydrogenase I was moderately inhibited by dicumarol, thenoyltrifluoroacetone, and the thiol reagent N-ethyl-maleimide. A strong inhibition of dehydrogenase II was obtained with dicumarol, thenoyltrifluoroacetone, and the thiol reagent p-hydroxymercuribenzoate. PMID:12232306

  17. Thioredoxin and NADPH-Dependent Thioredoxin Reductase C Regulation of Tetrapyrrole Biosynthesis.

    PubMed

    Da, Qingen; Wang, Peng; Wang, Menglong; Sun, Ting; Jin, Honglei; Liu, Bing; Wang, Jinfa; Grimm, Bernhard; Wang, Hong-Bin

    2017-10-01

    In chloroplasts, thioredoxin (TRX) isoforms and NADPH-dependent thioredoxin reductase C (NTRC) act as redox regulatory factors involved in multiple plastid biogenesis and metabolic processes. To date, less is known about the functional coordination between TRXs and NTRC in chlorophyll biosynthesis. In this study, we aimed to explore the potential functions of TRX m and NTRC in the regulation of the tetrapyrrole biosynthesis (TBS) pathway. Silencing of three genes, TRX m1 , TRX m2 , and TRX m4 ( TRX ms ), led to pale-green leaves, a significantly reduced 5-aminolevulinic acid (ALA)-synthesizing capacity, and reduced accumulation of chlorophyll and its metabolic intermediates in Arabidopsis ( Arabidopsis thaliana ). The contents of ALA dehydratase, protoporphyrinogen IX oxidase, the I subunit of Mg-chelatase, Mg-protoporphyrin IX methyltransferase (CHLM), and NADPH-protochlorophyllide oxidoreductase were decreased in triple TRX m- silenced seedlings compared with the wild type, although the transcript levels of the corresponding genes were not altered significantly. Protein-protein interaction analyses revealed a physical interaction between the TRX m isoforms and CHLM. 4-Acetoamido-4-maleimidylstilbene-2,2-disulfonate labeling showed the regulatory impact of TRX ms on the CHLM redox status. Since CHLM also is regulated by NTRC (Richter et al., 2013), we assessed the concurrent functions of TRX m and NTRC in the control of CHLM. Combined deficiencies of three TRX m isoforms and NTRC led to a cumulative decrease in leaf pigmentation, TBS intermediate contents, ALA synthesis rate, and CHLM activity. We discuss the coordinated roles of TRX m and NTRC in the redox control of CHLM stability with its corollary activity in the TBS pathway. © 2017 American Society of Plant Biologists. All Rights Reserved.

  18. Serotonin produces monoamine oxidase-dependent oxidative stress in human heart valves.

    PubMed

    Peña-Silva, Ricardo A; Miller, Jordan D; Chu, Yi; Heistad, Donald D

    2009-10-01

    Heart valve disease and pulmonary hypertension, in patients with carcinoid tumors and people who used the fenfluramine-phentermine combination for weight control, have been associated with high levels of serotonin in blood. The mechanism by which serotonin induces valvular changes is not well understood. We recently reported that increased oxidative stress is associated with valvular changes in aortic valve stenosis in humans and mice. In this study, we tested the hypothesis that serotonin induces oxidative stress in human heart valves, and examined mechanisms by which serotonin may increase reactive oxygen species. Superoxide (O2*.-) was measured in heart valves from explanted human hearts that were not used for transplantation. (O2*.-) levels (lucigenin-enhanced chemoluminescence) were increased in homogenates of cardiac valves and blood vessels after incubation with serotonin. A nonspecific inhibitor of flavin-oxidases (diphenyliodonium), or inhibitors of monoamine oxidase [MAO (tranylcypromine and clorgyline)], prevented the serotonin-induced increase in (O2*.-). Dopamine, another MAO substrate that is increased in patients with carcinoid syndrome, also increased (O2*.-) levels in heart valves, and this effect was attenuated by clorgyline. Apocynin [an inhibitor of NAD(P)H oxidase] did not prevent increases in (O2*.-) during serotonin treatment. Addition of serotonin to recombinant human MAO-A generated (O2*.-), and this effect was prevented by an MAO inhibitor. In conclusion, we have identified a novel mechanism whereby MAO-A can contribute to increased oxidative stress in human heart valves and pulmonary artery exposed to serotonin and dopamine.

  19. The potential antifibrotic impact of apocynin and alpha-lipoic acid in concanavalin A-induced liver fibrosis in rats: Role of NADPH oxidases 1 and 4.

    PubMed

    Fayed, Mostafa R; El-Naga, Reem N; Akool, El-Sayed; El-Demerdash, Ebtehal

    2018-01-01

    Liver fibrosis results from chronic inflammation that precipitates excessive accumulation of extracellular matrix. Oxidative stress is involved in its pathogenesis. This study aimed to elucidate the potential antifibrotic effect of the NADPH oxidase (NOX) inhibitor, apocynin against concanavalin A (ConA)-induced immunological model of liver fibrosis, and to investigate the ability of the antioxidant, alpha-lipoic acid (α-LA) to potentiate this effect. Rats were treated with apocynin and/or α-LA for six weeks. Hepatotoxicity indices, oxidative stress, insulin, NOXs, inflammatory and liver fibrosis markers were assessed. Treatment of animals with apocynin and α-LA significantly ameliorated the changes in liver functions and histopathological architecture induced by ConA. Liver fibrosis induced by ConA was evident where alpha-smooth muscle actin and transforming growth factor- beta1 were elevated, which was further confirmed by Masson's trichrome stain and increased hydroxyproline. Co-treatment with apocynin and α-LA significantly reduced their expression. Besides, apocynin and α-LA significantly ameliorated oxidative stress injury evoked by ConA, as evidenced by enhancing reduced glutathione content, antioxidant enzymes activities and decreasing lipid peroxides. ConA induced a significant elevation in serum insulin level and inflammatory markers; tumor necrosis factor-alpha, interleukin-6 and nuclear factor kappa b. Furthermore, the mRNA tissue expression of NOXs 1 and 4 was found to be elevated in the ConA group. All these elevations were significantly reduced by apocynin and α-LA co-treatment. These findings indicate that using apocynin and α-LA in combination possess marked antifibrotic effects, and that NOX enzymes are partially involved in the pathogenesis of ConA-induced liver fibrosis.

  20. PPAR{alpha} agonist fenofibrate protects the kidney from hypertensive injury in spontaneously hypertensive rats via inhibition of oxidative stress and MAPK activity

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

    Hou, Xiaoyang; Division of Cardiothoracic Surgery, The Michael E. DeBakey Department of Surgery, Baylor College of Medicine, BCM 390, One Baylor Plaza, Houston, TX 77030; Shen, Ying H.

    2010-04-09

    Oxidative stress has been shown to play an important role in the development of hypertensive renal injury. Peroxisome proliferator-activated receptors {alpha} (PPAR{alpha}) has antioxidant effect. In this study, we demonstrated that fenofibrate significantly reduced proteinuria, inflammatory cell recruitment and extracellular matrix (ECM) proteins deposition in the kidney of SHRs without apparent effect on blood pressure. To investigate the mechanisms involved, we found that fenofibrate treatment markedly reduced oxidative stress accompanied by reduced activity of renal NAD(P)H oxidase, increased activity of Cu/Zn SOD, and decreased phosphorylation of p38MAPK and JNK in the kidney of SHRs. Taken together, fenofibrate treatment can protectmore » against hypertensive renal injury without affecting blood pressure by inhibiting inflammation and fibrosis via suppression of oxidative stress and MAPK activity.« less