Redox system and phospholipid metabolism in the kidney of hypertensive rats after FAAH inhibitor URB597 administration.

PubMed

Biernacki, Michał; Ambrożewicz, Ewa; Gęgotek, Agnieszka; Toczek, Marek; Bielawska, Katarzyna; Skrzydlewska, Elżbieta

2018-05-01

Primary and secondary hypertension is associated with kidney redox imbalance resulting in enhanced reactive oxygen species (ROS) and enzymes dependent phospholipid metabolism. The fatty acid amide hydrolase inhibitor, URB597, modulates the levels of endocannabinoids, particularly of anandamide, which is responsible for controlling blood pressure and regulating redox balance. Therefore, this study aimed to compare the effects of chronic URB597 administration to spontaneously hypertensive rats (SHR) and rats with secondary hypertension (DOCA-salt rats) on the kidney metabolism associated with the redox and endocannabinoid systems. It was shown fatty acid amide hydrolase (FAAH) inhibitor decreased the activity of ROS-generated enzymes what resulted in a reduction of ROS level. Moreover varied changes in antioxidant parameters were observed with tendency to improve antioxidant defense in SHR kidney. Moreover, URB597 administration to hypertensive rats decreased pro-inflammatory response, particularly in the kidneys of DOCA-salt hypertensive rats. URB597 had tendency to enhance ROS-dependent phospholipid oxidation, estimated by changes in neuroprostanes in the kidney of SHR and reactive aldehydes (4-hydroxynonenal and malondialdehyde) in DOCA-salt rats, in particular. The administration of FAAH inhibitor resulted in increased level of endocannabinoids in kidney of both groups of hypertensive rats led to enhanced expression of the cannabinoid receptors type 1 and 2 in SHR as well as vanilloid receptor 1 receptors in DOCA-salt rats. URB597 given to normotensive rats also affected kidney oxidative metabolism, resulting in enhanced level of neuroprostanes in Wistar Kyoto rats and reactive aldehydes in Wistar rats. Moreover, the level of endocannabinoids and cannabinoid receptors were significantly higher in both control groups of rats after URB597 administration. In conclusion, because URB597 disturbed the kidney redox system and phospholipid ROS-dependent and enzymatic-dependent metabolism, the administration of this inhibitor may enhance kidney disorders depending on model of hypertension, but may also cause kidney disturbances in control rats. Therefore, further studies are warranted. Copyright © 2017 The Authors. Published by Elsevier B.V. All rights reserved.

Extract from Edible Red Seaweed (Gelidium amansii) Inhibits Lipid Accumulation and ROS Production during Differentiation in 3T3-L1 Cells.

PubMed

Seo, Min-Jung; Lee, Ok-Hwan; Choi, Hyeon-Son; Lee, Boo-Yong

2012-06-01

Gelidium (G.) amansii is a red alga widely distributed in the shallow waters around East Asian countries. We investigated the effect of G. amansii on lipid accumulation and ROS (Reactive Oxygen Species) production in 3T3-L1 cells. G. amansii extracts dose-dependently inhibited lipid formation and ROS generation in cultured cells. Our results showed that anti-adipogenic effect of G. amansii was due to the reduction in mRNA expressions of PPARγ peroxisome proliferator-activated receptor-γ and aP2 (adipocyte protein 2). G. amansii extracts significantly decreased mRNA levels of a ROS-generator, NOX4 (nicotinamide adenine dinucleotide phosphate hydrogen oxidase 4), and increased the protein levels of antioxidant enzymes including SOD1/2 (superoxide dis-mutases), Gpx (glutathione peroxidase), and GR (glutathione reductase), which can lead to the reduction of ROS in the cell. In addition, the G. amansii extract enhanced mRNA levels of adiponectin, one of the adipokines secreted from adipocytes, and GLUT4, glucose uptake protein. Taken together, our study shows that G. amansii extract inhibited lipid accumulation and ROS production by controlling adipogenic signals and ROS regulating genes.

Extract from Edible Red Seaweed (Gelidium amansii) Inhibits Lipid Accumulation and ROS Production during Differentiation in 3T3-L1 Cells

PubMed Central

Seo, Min-Jung; Lee, Ok-Hwan; Choi, Hyeon-Son; Lee, Boo-Yong

2012-01-01

Gelidium (G.) amansii is a red alga widely distributed in the shallow waters around East Asian countries. We investigated the effect of G. amansii on lipid accumulation and ROS (Reactive Oxygen Species) production in 3T3-L1 cells. G. amansii extracts dose-dependently inhibited lipid formation and ROS generation in cultured cells. Our results showed that anti-adipogenic effect of G. amansii was due to the reduction in mRNA expressions of PPARγ peroxisome proliferator-activated receptor-γ and aP2 (adipocyte protein 2). G. amansii extracts significantly decreased mRNA levels of a ROS-generator, NOX4 (nicotinamide adenine dinucleotide phosphate hydrogen oxidase 4), and increased the protein levels of antioxidant enzymes including SOD1/2 (superoxide dis-mutases), Gpx (glutathione peroxidase), and GR (glutathione reductase), which can lead to the reduction of ROS in the cell. In addition, the G. amansii extract enhanced mRNA levels of adiponectin, one of the adipokines secreted from adipocytes, and GLUT4, glucose uptake protein. Taken together, our study shows that G. amansii extract inhibited lipid accumulation and ROS production by controlling adipogenic signals and ROS regulating genes. PMID:24471074

Reactive Oxygen Species Generation-Scavenging and Signaling during Plant-Arbuscular Mycorrhizal and Piriformospora indica Interaction under Stress Condition.

PubMed

Nath, Manoj; Bhatt, Deepesh; Prasad, Ram; Gill, Sarvajeet S; Anjum, Naser A; Tuteja, Narendra

2016-01-01

A defined balance between the generation and scavenging of reactive oxygen species (ROS) is essential to utilize ROS as an adaptive defense response of plants under biotic and abiotic stress conditions. Moreover, ROS are not only a major determinant of stress response but also act as signaling molecule that regulates various cellular processes including plant-microbe interaction. In particular, rhizosphere constitutes the biologically dynamic zone for plant-microbe interactions which forms a mutual link leading to reciprocal signaling in both the partners. Among plant-microbe interactions, symbiotic associations of arbuscular mycorrhizal fungi (AMF) and arbuscular mycorrhizal-like fungus especially Piriformospora indica with plants are well known to improve plant growth by alleviating the stress-impacts and consequently enhance the plant fitness. AMF and P. indica colonization mainly enhances ROS-metabolism, maintains ROS-homeostasis, and thereby averts higher ROS-level accrued inhibition in plant cellular processes and plant growth and survival under stressful environments. This article summarizes the major outcomes of the recent reports on the ROS-generation, scavenging and signaling in biotic-abiotic stressed plants with AMF and P. indica colonization. Overall, a detailed exploration of ROS-signature kinetics during plant-AMF/ P. indica interaction can help in designing innovative strategies for improving plant health and productivity under stress conditions.

Enhancement of ε-poly-L-lysine synthesis in Streptomyces by exogenous glutathione.

PubMed

Yan, Peng; Sun, Haoben; Lu, Pengqi; Liu, Haili; Tang, Lei

2018-01-01

Our previous work indicated that the vigor of Streptomyces decreased at the later stage of ε-poly-L-lysine (ε-PL) fermentation. In this study, we observed that the level of reactive oxygen species (ROS) in vivo increased sharply after 24 h, and the addition of an antioxidant glutathione (GSH) before this increase in ROS stimulated ε-PL synthesis in shake-flask fermentation. The enhancement of ε-PL production by GSH was further verified in batch and fed-batch fermentations. On a 5-l fermenter scale, the highest increasement was 68.8% in batch fermentation and the highest ε-PL level was 46.5 g l - 1 in fed-batch fermentation. The RT-qPCR analysis showed that the transcriptional level of the catalase gene was down-regulated, and the decrease in cell activity was alleviated by the addition of GSH. The results revealed that exogenous antioxidant might maintain the cell vigor by reducing the excess ROS which provided a novel approach to regulate ε-PL synthesis.

Impressive Suppression of Colon Cancer Growth by Triple Combination SN38/EF24/Melatonin: "Oncogenic" Versus "Onco-Suppressive" Reactive Oxygen Species.

PubMed

Bakalova, Rumiana; Zhelev, Zhivko; Shibata, Sayaka; Nikolova, Biliana; Aoki, Ichio; Higashi, Tatsuya

2017-10-01

The study aimed to investigate the effect of multi-targeted combinations (SN38/EF24; SN38/EF24/melatonin) on the growth of colon cancer in experimental animals and their impact on the ratio "oncogenic"/"onco-suppressive" reactive oxygen species (ROS) - a crucial factor for triggering carcinogenesis, as well as for development of effective therapeutic strategies. The experiments were conducted on colon cancer-grafted mice - non-treated, SN38/EF24-treated and SN38/EF24/melatonin-treated within 22 days. The balance between different types of ROS was measured in vivo by nitroxide-enhanced magnetic resonance imaging (MRI), as well as on isolated tissue specimens by conventional analytical tests. Both combinations significantly suppressed the tumor growth. Impressive anticancer effect was observed in SN38/EF24/melatonin-treated mice - almost complete destruction of the tumor. Both types of ROS (superoxide and hydroperoxides) were elevated in cancer, but the MRI data suggest that the ratio between them tends towards superoxide. SN38/EF24 decreased the level of superoxide, but did not affect the level of hydroperoxides in the cancerous tissue, while SN38/EF24/melatonin decreased the level of superoxide below the control and increased significantly the level of hydroperoxides. The most important observations are that: (i) colon cancer was characterized by a vicious cycle, that ensures a permanent domination of "oncogenic" ROS (as superoxide) over "onco-suppressive" ROS (as hydrogen peroxide); (ii) the anticancer effect of the triple combination EF24/SN38/melatonin was accompanied by decreasing "oncogenic" and increasing "onco-suppressive" ROS; (iii) the ratio between both types of ROS could be a new onco-target for combined therapy; and (iv) nitroxide-enhanced MRI is a valuable tool for analyzing of this ratio. Copyright© 2017, International Institute of Anticancer Research (Dr. George J. Delinasios), All rights reserved.

Docosahexaenoic acid prevents paraquat-induced reactive oxygen species production in dopaminergic neurons via enhancement of glutathione homeostasis

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

Lee, Hyoung Jun; Han, Jeongsu; Jang, Yunseon

Highlights: • DHA prevents PQ-induced dopaminergic neuronal loss via decreasing of excessive ROS. • DHA increases GR and GCLm derivate GSH pool by enhancement of Nrf2 expression. • Protective mechanism is removal of PQ-induced ROS via DHA-dependent GSH pool. • DHA may be a good preventive strategy for Parkinson’s disease (PD) therapy. - Abstract: Omega-3 polyunsaturated fatty acid levels are reduced in the substantia nigra area in Parkinson’s disease patients and animal models, implicating docosahexaenoic acid (DHA) as a potential treatment for preventing Parkinson’s disease and suggesting the need for investigations into how DHA might protect against neurotoxin-induced dopaminergic neuronmore » loss. The herbicide paraquat (PQ) induces dopaminergic neuron loss through the excessive production of reactive oxygen species (ROS). We found that treatment of dopaminergic SN4741 cells with PQ reduced cell viability in a dose-dependent manner, but pretreatment with DHA ameliorated the toxic effect of PQ. To determine the toxic mechanism of PQ, we measured intracellular ROS content in different organelles with specific dyes. As expected, all types of ROS were increased by PQ treatment, but DHA pretreatment selectively decreased cytosolic hydrogen peroxide content. Furthermore, DHA treatment-induced increases in glutathione reductase and glutamate cysteine ligase modifier subunit (GCLm) mRNA expression were positively correlated with glutathione (GSH) content. Consistent with this increase in GCLm mRNA levels, Western blot analysis revealed that DHA pretreatment increased nuclear factor-erythroid 2 related factor 2 (Nrf2) protein levels. These findings indicate that DHA prevents PQ-induced neuronal cell loss by enhancing Nrf2-regulated GSH homeostasis.« less

PO2 cycling reduces diaphragm fatigue by attenuating ROS formation.

PubMed

Zuo, Li; Diaz, Philip T; Chien, Michael T; Roberts, William J; Kishek, Juliana; Best, Thomas M; Wagner, Peter D

2014-01-01

Prolonged muscle exposure to low PO2 conditions may cause oxidative stress resulting in severe muscular injuries. We hypothesize that PO2 cycling preconditioning, which involves brief cycles of diaphragmatic muscle exposure to a low oxygen level (40 Torr) followed by a high oxygen level (550 Torr), can reduce intracellular reactive oxygen species (ROS) as well as attenuate muscle fatigue in mouse diaphragm under low PO2. Accordingly, dihydrofluorescein (a fluorescent probe) was used to monitor muscular ROS production in real time with confocal microscopy during a lower PO2 condition. In the control group with no PO2 cycling, intracellular ROS formation did not appear during the first 15 min of the low PO2 period. However, after 20 min of low PO2, ROS levels increased significantly by ∼30% compared to baseline, and this increase continued until the end of the 30 min low PO2 condition. Conversely, muscles treated with PO2 cycling showed a complete absence of enhanced fluorescence emission throughout the entire low PO2 period. Furthermore, PO2 cycling-treated diaphragm exhibited increased fatigue resistance during prolonged low PO2 period compared to control. Thus, our data suggest that PO2 cycling mitigates diaphragm fatigue during prolonged low PO2. Although the exact mechanism for this protection remains to be elucidated, it is likely that through limiting excessive ROS levels, PO2 cycling initiates ROS-related antioxidant defenses.

Nutritional Countermeasures Targeting Reactive Oxygen Species in Cancer: From Mechanisms to Biomarkers and Clinical Evidence

PubMed Central

Samoylenko, Anatoly; Hossain, Jubayer Al; Mennerich, Daniela; Kellokumpu, Sakari; Hiltunen, Jukka Kalervo

2013-01-01

Abstract Reactive oxygen species (ROS) exert various biological effects and contribute to signaling events during physiological and pathological processes. Enhanced levels of ROS are highly associated with different tumors, a Western lifestyle, and a nutritional regime. The supplementation of food with traditional antioxidants was shown to be protective against cancer in a number of studies both in vitro and in vivo. However, recent large-scale human trials in well-nourished populations did not confirm the beneficial role of antioxidants in cancer, whereas there is a well-established connection between longevity of several human populations and increased amount of antioxidants in their diets. Although our knowledge about ROS generators, ROS scavengers, and ROS signaling has improved, the knowledge about the direct link between nutrition, ROS levels, and cancer is limited. These limitations are partly due to lack of standardized reliable ROS measurement methods, easily usable biomarkers, knowledge of ROS action in cellular compartments, and individual genetic predispositions. The current review summarizes ROS formation due to nutrition with respect to macronutrients and antioxidant micronutrients in the context of cancer and discusses signaling mechanisms, used biomarkers, and its limitations along with large-scale human trials. Antioxid. Redox Signal. 19, 2157–2196. PMID:23458328

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

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

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

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

Sodium dithionite-enhanced quality of radix scutellariae through modification of secondary metabolism

PubMed Central

Huimin, Guo; Xiaoying, Fu; Hongwei, Du; Wei, Cong; Xiangcai, Meng

2016-01-01

Introduction: The quality of radix scutellariae is particularly associated with environmental stresses, but detailed mechanisms remained unclear. Plant under unfavorable situation generates redundant reactive oxygen species (ROS), and ROS can modify the secondary metabolism. The varied quality of radix scutellariae could be explained by ROS. Materials and Methods: .004, 0.4, and 40 μmol/L of sodium dithionite (Na2S2O4), a material producing ROS, were applied to Scutellaria baicalensis to mimic unfavorable situation. The relationship between ROS, antioxidant enzymes activity, and secondary metabolite was investigated. Results: ROS level fails to rise due to both the antioxidase and the secondary metabolites. The activities of both superoxide dismutase and catalase in the roots of S. baicalensis showed a moderately improvement, meanwhile the phenylalanine ammonia lyase was strongly expressed, and the biosynthesis of flavonoids was heavily elevated. Although the glycosides such as baicalin and wogonoside changed little, the aglycones with the highest effective, such as baicalein and wogonin, were increased by approximately 50%-100%. Conclusion: This is very valuable in insight into the stress physiology and provides a strong tool to enhance the quality of radix scutellariae. PMID:28123992

GS-2, a pyrazolo[1,5-a]indole derivative with inhibitory activity of topoisomerases, exerts its potent cytotoxic activity by ROS generation.

PubMed

Ji, Yuan Yuan; Zhu, Yong Ming; Wang, Jian Wen

2013-11-01

Pyrazolo[1,5-a]indole derivatives, a new type of topoisomerase (topo) inhibitor, demonstrate a broad spectrum of antitumor activities. However, the mechanism underlying the induced cytotoxicity remains unclear. In this study, we investigated whether GS-2, one of the derivatives, altered the levels of ROS in breast cancer MDA-231 cells and whether these ROS contributed to the observed antitumoral activity. Our data revealed that GS-2 caused a time- and dose-dependent elevation of intracellular ROS level in MDA-231 cells. GS-2 subsequently elicited notable inhibition on the expression of topos, DNA damage, activation of caspase-3, -9. The loss of mitochondrial membrane potential (MMP) was observed during the induction. The addition of N-acetyl cysteine (NAC, a well-known antioxidant) could effectively attenuate the GS-2-induced ROS enhancement and subsequent apoptosis. NAC attenuated the induced inhibition on expression of topos, indicating that topos might be the target of GS-2-induced ROS. The finding of the induced ROS provides new evidence for the molecular mechanisms of antitumor activity of pyrazolo[1,5-a]indole derivatives. Copyright © 2013 Elsevier B.V. All rights reserved.

Contribution of reactive oxygen species to the anticancer activity of aminoalkanol derivatives of xanthone.

PubMed

Sypniewski, Daniel; Szkaradek, Natalia; Loch, Tomasz; Waszkielewicz, Anna M; Gunia-Krzyżak, Agnieszka; Matczyńska, Daria; Sołtysik, Dagna; Marona, Henryk; Bednarek, Ilona

2018-06-01

Reactive oxygen species (ROS) are critically involved in the action of anticancer agents. In this study, we investigated the role of ROS in the anticancer mechanism of new aminoalkanol derivatives of xanthone. Most xanthones used in the study displayed significant pro-oxidant effects similar to those of gambogic acid, one of the most active anticancer xanthones. The pro-oxidant activity of our xanthones was shown both directly (by determination of ROS induction, effects on the levels of intracellular antioxidants, and expression of antioxidant enzymes) and indirectly by demonstrating that the overexpression of manganese superoxide dismutase decreases ROS-mediated cell senescence. We also observed that mitochondrial dysfunction and cellular apoptosis enhancement correlated with xanthone-induced oxidative stress. Finally, we showed that the use of the antioxidant N-acetyl-L-cysteine partly reversed these effects of aminoalkanol xanthones. Our results demonstrated that novel aminoalkanol xanthones mediated their anticancer activity primarily through ROS elevation and enhanced oxidative stress, which led to mitochondrial cell death stimulation; this mechanism was similar to the activity of gambogic acid.

Opposing effects of TIGAR- and RAC1-derived ROS on Wnt-driven proliferation in the mouse intestine

PubMed Central

Cheung, Eric C.; Lee, Pearl; Ceteci, Fatih; Nixon, Colin; Blyth, Karen; Sansom, Owen J.; Vousden, Karen H.

2016-01-01

Reactive oxygen species (ROS) participate in numerous cell responses, including proliferation, DNA damage, and cell death. Based on these disparate activities, both promotion and inhibition of ROS have been proposed for cancer therapy. However, how the ROS response is determined is not clear. We examined the activities of ROS in a model of Apc deletion, where loss of the Wnt target gene Myc both rescues APC loss and prevents ROS accumulation. Following APC loss, Myc has been shown to up-regulate RAC1 to promote proliferative ROS through NADPH oxidase (NOX). However, APC loss also increased the expression of TIGAR, which functions to limit ROS. To explore this paradox, we used three-dimensional (3D) cultures and in vivo models to show that deletion of TIGAR increased ROS damage and inhibited proliferation. These responses were suppressed by limiting damaging ROS but enhanced by lowering proproliferative NOX-derived ROS. Despite having opposing effects on ROS levels, loss of TIGAR and RAC1 cooperated to suppress intestinal proliferation following APC loss. Our results indicate that the pro- and anti-proliferative effects of ROS can be independently modulated in the same cell, with two key targets in the Wnt pathway functioning to integrate the different ROS signals for optimal cell proliferation. PMID:26679840

A Permeable Cuticle Is Associated with the Release of Reactive Oxygen Species and Induction of Innate Immunity

PubMed Central

L'Haridon, Floriane; Besson-Bard, Angélique; Binda, Matteo; Serrano, Mario; Abou-Mansour, Eliane; Balet, Francine; Schoonbeek, Henk-Jan; Hess, Stephane; Mir, Ricardo; Léon, José; Lamotte, Olivier; Métraux, Jean-Pierre

2011-01-01

Wounded leaves of Arabidopsis thaliana show transient immunity to Botrytis cinerea, the causal agent of grey mould. Using a fluorescent probe, histological staining and a luminol assay, we now show that reactive oxygen species (ROS), including H2O2 and O2 −, are produced within minutes after wounding. ROS are formed in the absence of the enzymes Atrboh D and F and can be prevented by diphenylene iodonium (DPI) or catalase. H2O2 was shown to protect plants upon exogenous application. ROS accumulation and resistance to B. cinerea were abolished when wounded leaves were incubated under dry conditions, an effect that was found to depend on abscisic acid (ABA). Accordingly, ABA biosynthesis mutants (aba2 and aba3) were still fully resistant under dry conditions even without wounding. Under dry conditions, wounded plants contained higher ABA levels and displayed enhanced expression of ABA-dependent and ABA-reporter genes. Mutants impaired in cutin synthesis such as bdg and lacs2.3 are already known to display a high level of resistance to B. cinerea and were found to produce ROS even when leaves were not wounded. An increased permeability of the cuticle and enhanced ROS production were detected in aba2 and aba3 mutants as described for bdg and lacs2.3. Moreover, leaf surfaces treated with cutinase produced ROS and became more protected to B. cinerea. Thus, increased permeability of the cuticle is strongly linked with ROS formation and resistance to B. cinerea. The amount of oxalic acid, an inhibitor of ROS secreted by B. cinerea could be reduced using plants over expressing a fungal oxalate decarboxylase of Trametes versicolor. Infection of such plants resulted in a faster ROS accumulation and resistance to B. cinerea than that observed in untransformed controls, demonstrating the importance of fungal suppression of ROS formation by oxalic acid. Thus, changes in the diffusive properties of the cuticle are linked with the induction ROS and attending innate defenses. PMID:21829351

Parkin clearance of dysfunctional mitochondria regulates ROS levels and increases survival of human chondrocytes.

PubMed

Ansari, M Y; Khan, N M; Ahmad, I; Haqqi, T M

2017-08-08

Mitochondrial dysfunction, oxidative stress and chondrocyte death are important contributors to the development and pathogenesis of osteoarthritis (OA). In this study, we determined the expression and role of Parkin in the clearance of damaged/dysfunctional mitochondria, regulation of reactive oxygen species (ROS) levels and chondrocyte survival under pathological conditions. Human chondrocytes were from the unaffected area of knee OA cartilage (n = 12) and were stimulated with IL-1β to mimic pathological conditions. Mitochondrial membrane depolarization and ROS levels were determined using specific dyes and flow cytometry. Autophagy was determined by Western blotting for ATG5, Beclin1, immunofluorescence staining and confocal microscopy. Gene expression was determined by RT-qPCR. siRNA, wild-type and mutant Parkin plasmids were transfected using Amaxa system. Apoptosis was determined by PI staining of chondrocytes and TUNEL assay. IL-1β-stimulated OA chondrocytes showed high levels of ROS generation, mitochondrial membrane damage, accumulation of damaged mitochondria and higher incidence of apoptosis. IL-1β stimulation of chondrocytes with depleted Parkin expression resulted in sustained high levels of ROS, accumulation of damaged/dysfunctional mitochondria and enhanced apoptosis. Parkin translocation to depolarized/damaged mitochondria and recruitment of p62/SQSTM1 was required for the elimination of damaged/dysfunctional mitochondria in IL-1β-stimulated OA chondrocytes. Importantly we demonstrate that Parkin elimination of depolarized/damaged mitochondria required the Parkin ubiquitin ligase activity and resulted in reduced ROS levels and inhibition of apoptosis in OA chondrocytes under pathological conditions. Our data demonstrates that Parkin functions to eliminate depolarized/damaged mitochondria in chondrocytes which is necessary for mitochondrial quality control, regulation of ROS levels and chondrocyte survival under pathological conditions. Copyright © 2017 Osteoarthritis Research Society International. Published by Elsevier Ltd. All rights reserved.

Stabilization of superoxide dismutase by acetyl-l-carnitine in human brain endothelium during alcohol exposure: novel protective approach.

PubMed

Haorah, James; Floreani, Nicholas A; Knipe, Bryan; Persidsky, Yuri

2011-10-15

Oxidative damage of the endothelium disrupts the integrity of the blood-brain barrier (BBB). We have shown before that alcohol exposure increases the levels of reactive oxygen species (ROS; superoxide and hydroxyl radical) and nitric oxide (NO) in brain endothelial cells by activating NADPH oxidase and inducible nitric oxide synthase. We hypothesize that impairment of antioxidant systems, such as a reduction in catalase and superoxide dismutase (SOD) activity, by ethanol exposure may elevate the levels of ROS/NO in endothelium, resulting in BBB damage. This study examines whether stabilization of antioxidant enzyme activity results in suppression of ROS levels by anti-inflammatory agents. To address this idea, we determined the effects of ethanol on the kinetic profile of SOD and catalase activity and ROS/NO generation in primary human brain endothelial cells (hBECs). We observed an enhanced production of ROS and NO levels due to the metabolism of ethanol in hBECs. Similar increases were found after exposure of hBECs to acetaldehyde, the major metabolite of ethanol. Ethanol simultaneously augmented ROS generation and the activity of antioxidative enzymes. SOD activity was increased for a much longer period of time than catalase activity. A decline in SOD activity and protein levels preceded elevation of oxidant levels. SOD stabilization by the antioxidant and mitochondria-protecting agent acetyl-L-carnitine (ALC) and the anti-inflammatory agent rosiglitazone suppressed ROS levels, with a marginal increase in NO levels. Mitochondrial membrane protein damage and decreased membrane potential after ethanol exposure indicated mitochondrial injury. These changes were prevented by ALC. Our findings suggest the counteracting mechanisms of oxidants and antioxidants during alcohol-induced oxidative stress at the BBB. The presence of enzymatic stabilizers favors the ROS-neutralizing antioxidant redox of the BBB, suggesting an underlying protective mechanism of NO for brain vascular tone and vasodilation. Published by Elsevier Inc.

Hematopoietic Stem Cell Regeneration Enhanced by Ectopic Expression of ROS-detoxifying Enzymes in Transplant Mice

PubMed Central

Miao, Weimin; XuFeng, Richard; Park, Moo-Rim; Gu, Haihui; Hu, Linping; Kang, Jin Wook; Ma, Shihui; Liang, Paulina H; Li, Yanxin; Cheng, Haizi; Yu, Hui; Epperly, Michael; Greenberger, Joel; Cheng, Tao

2013-01-01

High levels of reactive oxygen species (ROS) can exhaust hematopoietic stem cells (HSCs). Thus, maintaining a low state of redox in HSCs by modulating ROS-detoxifying enzymes may augment the regeneration potential of HSCs. Our results show that basal expression of manganese superoxide dismutase (MnSOD) and catalase were at low levels in long-term and short-term repopulating HSCs, and administration of a MnSOD plasmid and lipofectin complex (MnSOD-PL) conferred radiation protection on irradiated recipient mice. To assess the intrinsic role of elevated MnSOD or catalase in HSCs and hematopoietic progenitor cells, the MnSOD or catalase gene was overexpressed in mouse hematopoietic cells via retroviral transduction. The impact of MnSOD and catalase on hematopoietic progenitor cells was mild, as measured by colony-forming units (CFUs). However, overexpressed catalase had a significant beneficial effect on long-term engraftment of transplanted HSCs, and this effect was further enhanced after an insult of low-dose γ-irradiation in the transplant mice. In contrast, overexpressed MnSOD exhibited an insignificant effect on long-term engraftment of transplanted HSCs, but had a significant beneficial effect after an insult of sublethal irradiation. Taken together, these results demonstrate that HSC function can be enhanced by ectopic expression of ROS-detoxifying enzymes, especially after radiation exposure in vivo. PMID:23295952

2-Deoxy-D-glucose Sensitizes Cancer Cells to Barasertib and Everolimus by ROS-independent Mechanism(s).

PubMed

Zhelev, Zhivko; Ivanova, Donika; Aoki, Ichio; Saga, Tsuneo; Bakalova, Rumiana

2015-12-01

The aim of the present study was to investigate: (i) the possibility of sensitizing cancer cells to anticancer drugs using the redox modulator 2-deoxy-D-glucose (2-DDG); (ii) to find such combinations with synergistic cytotoxic effect; (iii) and to clarify the role of reactive oxygen species (ROS) for induction of apoptosis and cytotoxicity through these combinations. The study covers 15 anticancer drugs--both conventional and new-generation. Four parameters were analyzed simultaneously in Jurkat leukemia cells, treated by drugs or 2-DDG (separately or in combination): cell viability, induction of apoptosis, levels of ROS, and level of protein-carbonyl products. Very well-expressed synergistic cytotoxic effects were found after 48-h treatment of Jurkat cells with 2-DDG in combination with: palbociclib, everolimus, lonafarnib, bortezomib, and barasertib. The synergistic cytotoxic effect of everolimus with 2-DDG was accompanied by very strong induction of apoptosis in cells, but a very strong reduction of ROS level. Changes in the levels of protein-carbonyl products were not detected. The synergistic cytotoxic effect of barasertib with 2-DDG was accompanied by very strong induction of apoptosis in cells, without any increase of ROS levels, but with an enhancement of protein-carbonyl products. Copyright© 2015 International Institute of Anticancer Research (Dr. John G. Delinassios), All rights reserved.

Enhanced oxidative stress in workers with a standing occupation

PubMed Central

Flore, R; Gerardino, L; Santoliquido, A; Pola, R; Flex, A; Di, C; Pola, P; Tondi, P

2004-01-01

Aims and Methods: To evaluate venous pressure of the lower limbs and reactive oxygen species (ROS) before and after work in 62 workers with a standing occupation (surgery room nurses) and 65 outpatient department nurses who can walk during their working time. Results: After work, a statistically significant increase of venous pressure of the lower limbs levels was observed in both the study group and controls. Standing workers showed significantly higher mean levels of ROS after work. PMID:15150396

Tryptophan depletion under conditions that imitate insulin resistance enhances fatty acid oxidation and induces endothelial dysfunction through reactive oxygen species-dependent and independent pathways.

PubMed

Eleftheriadis, Theodoros; Pissas, Georgios; Sounidaki, Maria; Antoniadi, Georgia; Rountas, Christos; Liakopoulos, Vassilios; Stefanidis, Loannis

2017-04-01

In atherosclerosis-associated pathologic entities characterized by malnutrition and inflammation, L-tryptophan (TRP) levels are low. Insulin resistance is an independent cardiovascular risk factor and induces endothelial dysfunction by increasing fatty acid oxidation. It is also associated with inflammation and low TRP levels. Low TRP levels have been related to worse cardiovascular outcome. This study evaluated the effect of TRP depletion on endothelial dysfunction under conditions that imitate insulin resistance. Fatty acid oxidation, harmful pathways due to increased fatty acid oxidation, and endothelial dysfunction were assessed in primary human aortic endothelial cells cultured under normal glucose, low insulin conditions in the presence or absence of TRP. TRP depletion activated general control non-derepressible 2 kinase and inhibited aryl hydrocarbon receptor. It increased fatty acid oxidation by increasing expression and activity of carnitine palmitoyltransferase 1. Elevated fatty acid oxidation increased the formation of reactive oxygen species (ROS) triggering the polyol and hexosamine pathways, and enhancing protein kinase C activity and methylglyoxal production. TRP absence inhibited nitric oxide synthase activity in a ROS-dependent way, whereas it increased the expression of ICAM-1 and VCAM-1 in a ROS independent and possibly p53-dependent manner. Thus, TRP depletion, an amino acid whose low levels have been related to worse cardiovascular outcome and to inflammatory atherosclerosis-associated pathologic entities, under conditions that imitate insulin resistance enhances fatty acid oxidation and induces endothelial dysfunction through ROS-dependent and independent pathways. These findings may offer new insights at the molecular mechanisms involved in accelerated atherosclerosis that frequently accompanies malnutrition and inflammation.

Magmas functions as a ROS regulator and provides cytoprotection against oxidative stress-mediated damages

PubMed Central

Srivastava, S; Sinha, D; Saha, P P; Marthala, H; D'Silva, P

2014-01-01

Redox imbalance generates multiple cellular damages leading to oxidative stress-mediated pathological conditions such as neurodegenerative diseases and cancer progression. Therefore, maintenance of reactive oxygen species (ROS) homeostasis is most important that involves well-defined antioxidant machinery. In the present study, we have identified for the first time a component of mammalian protein translocation machinery Magmas to perform a critical ROS regulatory function. Magmas overexpression has been reported in highly metabolically active tissues and cancer cells that are prone to oxidative damage. We found that Magmas regulates cellular ROS levels by controlling its production as well as scavenging. Magmas promotes cellular tolerance toward oxidative stress by enhancing antioxidant enzyme activity, thus preventing induction of apoptosis and damage to cellular components. Magmas enhances the activity of electron transport chain (ETC) complexes, causing reduced ROS production. Our results suggest that J-like domain of Magmas is essential for maintenance of redox balance. The function of Magmas as a ROS sensor was found to be independent of its role in protein import. The unique ROS modulatory role of Magmas is highlighted by its ability to increase cell tolerance to oxidative stress even in yeast model organism. The cytoprotective capability of Magmas against oxidative damage makes it an important candidate for future investigation in therapeutics of oxidative stress-related diseases. PMID:25165880

Reductions in the mitochondrial enzyme α-ketoglutarate dehydrogenase complex in neurodegenerative disease - beneficial or detrimental?

PubMed

Chen, Huanlian; Denton, Travis T; Xu, Hui; Calingasan, Noel; Beal, M Flint; Gibson, Gary E

2016-12-01

Reductions in metabolism and excess oxidative stress are prevalent in multiple neurodegenerative diseases. The activity of the mitochondrial enzyme α-ketoglutarate dehydrogenase complex (KGDHC) appears central to these abnormalities. KGDHC is diminished in multiple neurodegenerative diseases. KGDHC can not only be rate limiting for NADH production and for substrate level phosphorylation, but is also a source of reactive oxygen species (ROS). The goal of these studies was to determine how changes in KGDHC modify baseline ROS, the ability to buffer ROS, baseline glutathionylation, calcium modulation and cell death in response to external oxidants. In vivo, reducing KGDHC with adeno virus diminished neurogenesis and increased oxidative stress. In vitro, treatments of short duration increased ROS and glutathionylation and enhanced the ability of the cells to diminish the ROS from added oxidants. However, long-term reductions lessened the ability to diminish ROS, diminished glutathionylation and exaggerated oxidant-induced changes in calcium and cell death. Increasing KGDHC enhanced the ability of the cells to diminish externally added ROS and protected against oxidant-induced changes in calcium and cell death. The results suggest that brief periods of diminished KGDHC are protective, while prolonged reductions are harmful. Furthermore, elevated KGDHC activities are protective. Thus, mitogenic therapies that increase KGDHC may be beneficial in neurodegenerative diseases. Read the Editorial Highlight for this article on Page 689. © 2016 International Society for Neurochemistry.

Reactive Oxygen Species Tune Root Tropic Responses1[OPEN

PubMed Central

Krieger, Gat

2016-01-01

The default growth pattern of primary roots of land plants is directed by gravity. However, roots possess the ability to sense and respond directionally to other chemical and physical stimuli, separately and in combination. Therefore, these root tropic responses must be antagonistic to gravitropism. The role of reactive oxygen species (ROS) in gravitropism of maize and Arabidopsis (Arabidopsis thaliana) roots has been previously described. However, which cellular signals underlie the integration of the different environmental stimuli, which lead to an appropriate root tropic response, is currently unknown. In gravity-responding roots, we observed, by applying the ROS-sensitive fluorescent dye dihydrorhodamine-123 and confocal microscopy, a transient asymmetric ROS distribution, higher at the concave side of the root. The asymmetry, detected at the distal elongation zone, was built in the first 2 h of the gravitropic response and dissipated after another 2 h. In contrast, hydrotropically responding roots show no transient asymmetric distribution of ROS. Decreasing ROS levels by applying the antioxidant ascorbate, or the ROS-generation inhibitor diphenylene iodonium attenuated gravitropism while enhancing hydrotropism. Arabidopsis mutants deficient in Ascorbate Peroxidase 1 showed attenuated hydrotropic root bending. Mutants of the root-expressed NADPH oxidase RBOH C, but not rbohD, showed enhanced hydrotropism and less ROS in their roots apices (tested in tissue extracts with Amplex Red). Finally, hydrostimulation prior to gravistimulation attenuated the gravistimulated asymmetric ROS and auxin signals that are required for gravity-directed curvature. We suggest that ROS, presumably H2O2, function in tuning root tropic responses by promoting gravitropism and negatively regulating hydrotropism. PMID:27535793

Modulation of Rho-ROCK Signaling Pathway Protects Oligodendrocytes Against Cytokine Toxicity via PPAR-α-Dependent Mechanism

PubMed Central

Singh, Avtar K.; Singh, Inderjit

2013-01-01

We earlier documented that lovastatin (LOV)-mediated inhibition of small Rho GTPases activity protects vulnerable oligodendrocytes (OLs) in mixed glial cell cultures stimulated with Th1 cytokines and in a murine model of multiple sclerosis (MS). However, the precise mechanism of OL protection remains unclear. We here employed genetic and biochemical approaches to elucidate the underlying mechanism that protects LOV treated OLs from Th1 (tumor necrosis factor-α) and Th17 (interleukin-17) cytokines toxicity in in vitro. Cytokines enhanced the reactive oxygen species (ROS) generation and mitochondrial membrane depolarization with corresponding lowering of glutathione (reduced) level in OLs and that were reverted by LOV. In addition, the expression of ROS detoxifying enzymes (catalase and superoxide-dismutase 2) and the transactivation of peroxisome proliferators-activated receptor (PPAR)-α/-β/-γ including PPAR-γ coactivator-1α were enhanced by LOV in similarly treated OLs. Interestingly, LOV-mediated inhibition of small Rho GTPases, i.e., RhoA and cdc42, and Rho-associated kinase (ROCK) activity enhanced the levels of PPAR ligands in OLs via extracellular signal regulated kinase (1/2)/p38 mitogen-activated protein kinase/cytoplasmic phospholipase 2/cyclooxygenase-2 signaling cascade activation. Small hairpin RNA transfection-based studies established that LOV mainly enhances PPAR-α and less so of PPAR-β and PPAR-γ transactivation that enhances ROS detoxifying defense in OLs. In support of this, the observed LOV-mediated protection was lacking in PPAR-α-deficient OLs exposed to cytokines. Collectively, these data provide unprecedented evidence that LOV-mediated inhibition of the Rho–ROCK signaling pathway boosts ROS detoxifying defense in OLs via PPAR-α-dependent mechanism that has implication in neurodegenerative disorders including MS. PMID:23839981

Restraining reactive oxygen species in Listeria monocytogenes promotes the apoptosis of glial cells.

PubMed

Li, Sen; Li, Yixuan; Chen, Guowei; Zhang, Jingchen; Xu, Fei; Wu, Man

2017-07-01

Listeria monocytogenes is a facultative anaerobic foodborne pathogen that can traverse the blood-brain barrier and cause brain infection. L. monocytogenes infection induces host cell apoptosis in several cell types. In this study, we investigated the apoptosis of human glioma cell line U251 invaded by L. monocytogenes and evaluated the function of bacterial reactive oxygen species (ROS) during infection. Bacterial ROS level was reduced by carrying out treatment with N-acetyl cysteine (NAC) and diphenyleneiodonium chloride (DPI). After infection, the apoptosis of U251 cells was examined by flow cytometry assay and propidium iodide staining. DPI and NAC efficiently decreased ROS level in L. monocytogenes without affecting bacterial growth. Moreover, the apoptosis of glial cells was enhanced upon invasion of DPI- and NAC-pretreated L. monocytogenes. Results indicate that the apoptosis of glial cells can be induced by L. monocytogenes, and that the inhibition of bacterial ROS increases the apoptosis of host cells.

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

Sirt1 protects against oxidative stress-induced renal tubular cell apoptosis by the bidirectional regulation of catalase expression

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

Hasegawa, Kazuhiro; Wakino, Shu; Yoshioka, Kyoko

2008-07-18

NAD{sup +}-dependent protein deacetylase Sirt1 regulates cellular apoptosis. We examined the role of Sirt1 in renal tubular cell apoptosis by using HK-2 cells, proximal tubular cell lines with or without reactive oxygen species (ROS), H{sub 2}O{sub 2}. Without any ROS, Sirt1 inhibitors enhanced apoptosis and the expression of ROS scavenger, catalase, and Sirt1 overexpression downregulated catalase. When apoptosis was induced with H{sub 2}O{sub 2}, Sirt1 was upregulated with the concomitant increase in catalase expression. Sirt1 overexpression rescued H{sub 2}O{sub 2}-induced apoptosis through the upregulation of catalase. H{sub 2}O{sub 2} induced the nuclear accumulation of forkhead transcription factor, FoxO3a and themore » gene silencing of FoxO3a enhanced H{sub 2}O{sub 2}-induced apoptosis. In conclusion, endogenous Sirt1 maintains cell survival by regulating catalase expression and by preventing the depletion of ROS required for cell survival. In contrast, excess ROS upregulates Sirt1, which activates FoxO3a and catalase leading to rescuing apoptosis. Thus, Sirt1 constitutes a determinant of renal tubular cell apoptosis by regulating cellular ROS levels.« less

Enhanced Mitochondrial Transient Receptor Potential Channel, Canonical Type 3-Mediated Calcium Handling in the Vasculature From Hypertensive Rats.

PubMed

Wang, Bin; Xiong, Shiqiang; Lin, Shaoyang; Xia, Weijie; Li, Qiang; Zhao, Zhigang; Wei, Xing; Lu, Zongshi; Wei, Xiao; Gao, Peng; Liu, Daoyan; Zhu, Zhiming

2017-07-15

Mitochondrial Ca 2+ homeostasis is fundamental to the regulation of mitochondrial reactive oxygen species (ROS) generation and adenosine triphosphate production. Recently, transient receptor potential channel, canonical type 3 (TRPC3), has been shown to localize to the mitochondria and to play a role in maintaining mitochondrial calcium homeostasis. Inhibition of TRPC3 attenuates vascular calcium influx in spontaneously hypertensive rats (SHRs). However, it remains elusive whether mitochondrial TRPC3 participates in hypertension by increasing mitochondrial calcium handling and ROS production. In this study we demonstrated increased TRPC3 expression in purified mitochondria in the vasculature from SHRs, which facilitates enhanced mitochondrial calcium uptake and ROS generation compared with Wistar-Kyoto rats. Furthermore, inhibition of TRPC3 by its specific inhibitor, Pyr3, significantly decreased the vascular mitochondrial ROS production and H 2 O 2 synthesis and increased adenosine triphosphate content. Administration of telmisartan can improve these abnormalities. This beneficial effect was associated with improvement of the mitochondrial respiratory function through recovering the activity of pyruvate dehydrogenase in the vasculature of SHRs. In vivo, chronic administration of telmisartan suppressed TRPC3-mediated excessive mitochondrial ROS generation and vasoconstriction in the vasculature of SHRs. More importantly, TRPC3 knockout mice exhibited significantly ameliorated hypertension through reduction of angiotensin II-induced mitochondrial ROS generation. Together, we give experimental evidence for a potential mechanism by which enhanced TRPC3 activity at the cytoplasmic and mitochondrial levels contributes to redox signaling and calcium dysregulation in the vasculature from SHRs. Angiotensin II or telmisartan can regulate [Ca 2+ ] mito , ROS production, and mitochondrial energy metabolism through targeting TRPC3. © 2017 The Authors. Published on behalf of the American Heart Association, Inc., by Wiley.

Emodin enhances the chemosensitivity of endometrial cancer by inhibiting ROS-mediated Cisplatin-resistance.

PubMed

Ding, Ning; Zhang, Hong; Su, Shan; Ding, Yumei; Yu, Xiaohui; Tang, Yujie; Wang, Qingfang; Liu, Peishu

2017-12-18

Background Endometrial cancer is a common cause of death in gynecological malignancies. Cisplatin is a clinically chemotherapeutic agent. However, drug-resistance is the primary cause of treatment failure. Objective Emodin is commonly used clinically to increase the sensitivity of chemotherapeutic agents, yet whether Emodin promotes the role of Cisplatin in the treatment of endometrial cancer has not been studied. Method CCK-8 kit was utilized to determine the growth of two endometrial cancer cell lines, Ishikawa and HEC-IB. The apoptosis level of Ishikawa and HEC-IB cells was detected by Annexin V / propidium iodide double-staining assay. ROS level was detected by DCFH-DA and NADPH oxidase expression. Expressions of drug-resistant genes were examined by real-time PCR and Western blotting. Results Emodin combined with Cisplatin reduced cell growth and increased the apoptosis of endometrial cancer cells. Co-treatment of Emodin and Cisplatin increased chemosensitivity by inhibiting the expression of drug-resistant genes through reducing the ROS levels in endometrial cancer cells. In an endometrial cancer xenograft murine model, the tumor size was reduced and animal survival time was increased by co-treatment of Emodin and Cisplatin. Conclusion This study demonstrates that Emodin enhances the chemosensitivity of Cisplatin on endometrial cancer by inhibiting ROS-mediated expression of drug-resistance genes. Copyright© Bentham Science Publishers; For any queries, please email at epub@benthamscience.org.

Dietary thiols in exercise: oxidative stress defence, exercise performance, and adaptation.

PubMed

McLeay, Yanita; Stannard, Stephen; Houltham, Stuart; Starck, Carlene

2017-01-01

Endurance athletes are susceptible to cellular damage initiated by excessive levels of aerobic exercise-produced reactive oxygen species (ROS). Whilst ROS can contribute to the onset of fatigue, there is increasing evidence that they play a crucial role in exercise adaptations. The use of antioxidant supplements such as vitamin C and E in athletes is common; however, their ability to enhance performance and facilitate recovery is controversial, with many studies suggesting a blunting of training adaptations with supplementation. The up-regulation of endogenous antioxidant systems brought about by exercise training allows for greater tolerance to subsequent ROS, thus, athletes may benefit from increasing these systems through dietary thiol donors. Recent work has shown supplementation with a cysteine donor (N-acetylcysteine; NAC) improves antioxidant capacity by augmenting glutathione levels and reducing markers of oxidative stress, as well as ergogenic potential through association with delayed fatigue in numerous experimental models. However, the use of this, and other thiol donors may have adverse physiological effects. A recent discovery for the use of a thiol donor food source, keratin, to potentially enhance endogenous antioxidants may have important implications for endurance athletes hoping to enhance performance and recovery without blunting training adaptations.

Hypoxia-Induced Mesenchymal Stromal Cells Exhibit an Enhanced Therapeutic Effect on Radiation-Induced Lung Injury in Mice due to an Increased Proliferation Potential and Enhanced Antioxidant Ability.

PubMed

Li, Bailong; Li, Cheng; Zhu, Mo; Zhang, Youjun; Du, Jicong; Xu, Yang; Liu, Bin; Gao, Fu; Liu, Hu; Cai, Jianming; Yang, Yanyong

2017-01-01

Radiation therapy is an important treatment for thoracic cancer; however, side effects accompanied with radiotherapy lead to limited tumor control and a decline in patient quality of life. Among these side effects, radiation-induced lung injury (RILI) is the most serious and common. Hence, an effective remedy for RILI is needed. Mesenchymal stromal cells (MSCs) are multipotent adult stem cells that have been demonstrated to be an effective treatment in some disease caused by tissue damage. However, unlike other injuries, RILI received limited therapeutic effects from implanted MSCs due to local hypoxia and extensive reactive oxygen species (ROS) in irradiated lungs. Since the poor survival of MSCs is primarily due to hypoxia and ROS generation, we hypothesize that persistent and adaptive hypoxia treatment induces enhanced resistance to hypoxic stress in implanted MSC. The aim of this study is to investigate whether persistent and adaptive hypoxia treatment of bmMSCs prior to their transplantation in injured mice enhanced survival and improved curative effects in RILI. Primary bmMSCs were obtained from the marrow of six-week-old male C57BL6/J mice and were cultured either under normoxic conditions (21% O2) or hypoxic conditions (2.5% O2). Mice were injected with normoxia/hypoxia MSCs after thoracic irradiation (20 Gy). The therapeutic effects of MSCs on RILI were assessed by pathological examinations that included H&E staining, Masson staining and α-SMA staining; meanwhile, inflammatory factors were measured using an ELISA. The morphology of MSCs in vitro was recorded using a microscope and identified by flow cytometry, cell viability was measured using the CCK-8 assay, the potential for proliferation was detected by the EdU assay, and ROS levels were measured using a ROS fluorogenic probe. In addition, HIF-1α and several survival pathway proteins (Akt, p-Akt, Caspase-3) were also detected by western blotting. Implanted MSCs alleviated both early radiation-induced pneumonia and late pulmonary fibrosis. However, hypoxia MSCs displayed a more pronounced therapeutic effect compared to normoxia MSCs. Compared to normoxia MSCs, the hypoxia MSCs demonstrated greater cell viability, an enhanced proliferation potential, decreased ROS levels and increased resistance to hypoxia and ROS stress. In addition, hypoxia MSCs achieved higher activation levels of HIF-1α and Akt, and HIF-1α played a critical role in the development of resistance. Hypoxia enhances the therapeutic effect of mesenchymal stromal cells on radiation-induced lung injury by promoting MSC proliferation and improving their antioxidant ability, mediated by HIF-1α. © 2017 The Author(s). Published by S. Karger AG, Basel.

Deficiency of NPGPx, an oxidative stress sensor, leads to obesity in mice and human

PubMed Central

Chang, Yi-Cheng; Yu, Yu-Hsiang; Shew, Jin-Yuh; Lee, Wei-Jei; Hwang, Juey-Jen; Chen, Yen-Hui; Chen, Yet-Ran; Wei, Pei-Chi; Chuang, Lee-Ming; Lee, Wen-Hwa

2013-01-01

Elevated oxidative stress is closely associated with obesity. Emerging evidence shows that instead of being a consequence of obesity, oxidative stress may also contribute to fat formation. Nonselenocysteine-containing phospholipid hydroperoxide glutathione peroxidase (NPGPx) is a conserved oxidative stress sensor/transducer and deficiency of NPGPx causes accumulation of reactive oxygen species (ROS). In this communication, we show that NPGPx was highly expressed in preadipocytes of adipose tissue. Deficiency of NPGPx promoted preadipocytes to differentiate to adipocytes via ROS-dependent dimerization of protein kinase A regulatory subunits and activation of CCAAT/enhancer-binding protein beta (C/EBPβ). This enhanced adipogenesis was alleviated by antioxidant N-acetylcysteine (NAC). Consistently, NPGPx-deficient mice exhibited markedly increased fat mass and adipocyte hypertrophy, while treatment with NAC ablated these phenotypes. Furthermore, single nucleotide polymorphisms (SNPs) in human NPGPx gene, which correlated with lower NPGPx expression level in adipose tissue, were associated with higher body mass index (BMI) in several independent human populations. These results indicate that NPGPx protects against fat accumulation in mice and human via modulating ROS, and highlight the importance of targeting redox homeostasis in obesity management. Deficiency of the glutathione peroxidase NPGPx increases ROS levels in preadipocytes and promotes adipocyte differentiation via increasing oxidative stress and consequent increased fat mass and adipocyte hypertrophy. PMID:23828861

Ionizing radiation induces mitochondrial reactive oxygen species production accompanied by upregulation of mitochondrial electron transport chain function and mitochondrial content under control of the cell cycle checkpoint.

PubMed

Yamamori, Tohru; Yasui, Hironobu; Yamazumi, Masayuki; Wada, Yusuke; Nakamura, Yoshinari; Nakamura, Hideo; Inanami, Osamu

2012-07-15

Whereas ionizing radiation (Ir) instantaneously causes the formation of water radiolysis products that contain some reactive oxygen species (ROS), ROS are also suggested to be released from biological sources in irradiated cells. It is now becoming clear that these ROS generated secondarily after Ir have a variety of biological roles. Although mitochondria are assumed to be responsible for this Ir-induced ROS production, it remains to be elucidated how Ir triggers it. Therefore, we conducted this study to decipher the mechanism of Ir-induced mitochondrial ROS production. In human lung carcinoma A549 cells, Ir (10 Gy of X-rays) induced a time-dependent increase in the mitochondrial ROS level. Ir also increased mitochondrial membrane potential, mitochondrial respiration, and mitochondrial ATP production, suggesting upregulation of the mitochondrial electron transport chain (ETC) function after Ir. Although we found that Ir slightly enhanced mitochondrial ETC complex II activity, the complex II inhibitor 3-nitropropionic acid failed to reduce Ir-induced mitochondrial ROS production. Meanwhile, we observed that the mitochondrial mass and mitochondrial DNA level were upregulated after Ir, indicating that Ir increased the mitochondrial content of the cell. Because irradiated cells are known to undergo cell cycle arrest under control of the checkpoint mechanisms, we examined the relationships between cell cycle and mitochondrial content and cellular oxidative stress level. We found that the cells in the G2/M phase had a higher mitochondrial content and cellular oxidative stress level than cells in the G1 or S phase, regardless of whether the cells were irradiated. We also found that Ir-induced accumulation of the cells in the G2/M phase led to an increase in cells with a high mitochondrial content and cellular oxidative stress level. This suggested that Ir upregulated mitochondrial ETC function and mitochondrial content, resulting in mitochondrial ROS production, and that Ir-induced G2/M arrest contributed to the increase in the mitochondrial ROS level by accumulating cells in the G2/M phase. Copyright © 2012 Elsevier Inc. All rights reserved.

Abscisic acid synergizes with rosiglitazone to improve glucose tolerance, down-modulate macrophage accumulation in adipose tissue: possible action of the cAMP/PKA/PPAR γ axis

PubMed Central

Guri, Amir J; Hontecillas, Raquel; Bassaganya-Riera, Josep

2010-01-01

Background & Aims Abscisic acid (ABA) is effective in preventing insulin resistance and obesity-related inflammation through a PPAR γ-dependent mechanism. The objective of this study was to assess the efficacy ABA in improving glucose homeostasis and suppress inflammation when administered in combination with rosiglitazone (Ros) and to determine whether PPAR γ activation by ABA is initiated via cAMP/protein kinase A (PKA) signaling. Methods Obese db/db mice were fed high-fat diets containing 0, 10, or 70 mg/kg Ros with and without racemic ABA (100 mg/kg) for 60 days. Glucose tolerance and fasting insulin levels were assessed at 6 and 8 weeks, respectively, and adipose tissue macrophage (ATM) infiltration was examined by flow cytometry. Gene expression was examined on white adipose tissue (WAT) and stromal vascular cells (SVCs) cultured with ABA, Ros, or an ABA/Ros combination. Results Both Ros and ABA improved glucose tolerance, and ABA decreased plasma insulin levels while having no effect on Ros-induced weight gain. ABA in combination with low-dose Ros (10 mg/kg; Roslo) synergistically inhibited ATM infiltration. Treatment of SVCs with Ros, ABA or ABA/Ros suppressed expression of the M1 marker CCL17. ABA and Ros synergistically increased PPAR γ activity and pretreatment with a cAMP-inhibitor or a PKA-inhibitor abrogated ABA-induced PPAR γ activation. Conclusions ABA and Ros act synergistically to modulate PPAR γ activity and macrophage accumulation in WAT and ABA enhances PPAR γ activity through a membrane-initiated mechanism dependent on cAMP/PKA signaling. PMID:20207056

Abscisic acid synergizes with rosiglitazone to improve glucose tolerance and down-modulate macrophage accumulation in adipose tissue: possible action of the cAMP/PKA/PPAR γ axis.

PubMed

Guri, Amir J; Hontecillas, Raquel; Bassaganya-Riera, Josep

2010-10-01

Abscisic acid (ABA) is effective in preventing insulin resistance and obesity-related inflammation through a PPAR γ-dependent mechanism. The objective of this study was to assess the efficacy ABA in improving glucose homeostasis and suppress inflammation when administered in combination with rosiglitazone (Ros) and to determine whether PPAR γ activation by ABA is initiated via cAMP/protein kinase A (PKA) signaling. Obese db/db mice were fed high-fat diets containing 0, 10, or 70 mg/kg Ros with and without racemic ABA (100 mg/kg) for 60 days. Glucose tolerance and fasting insulin levels were assessed at 6 and 8 weeks, respectively, and adipose tissue macrophage (ATM) infiltration was examined by flow cytometry. Gene expression was examined on white adipose tissue (WAT) and stromal vascular cells (SVCs) cultured with ABA, Ros, or an ABA/Ros combination. Both Ros and ABA improved glucose tolerance, and ABA decreased plasma insulin levels while having no effect on Ros-induced weight gain. ABA in combination with low-dose Ros (10 mg/kg; Roslo) synergistically inhibited ATM infiltration. Treatment of SVCs with Ros, ABA or ABA/Ros suppressed expression of the M1 marker CCL17. ABA and Ros synergistically increased PPAR γ activity and pretreatment with a cAMP-inhibitor or a PKA-inhibitor abrogated ABA-induced PPAR γ activation. ABA and Ros act synergistically to modulate PPAR γ activity and macrophage accumulation in WAT and ABA enhances PPAR γ activity through a membrane-initiated mechanism dependent on cAMP/PKA signaling. Copyright © 2010 Elsevier Ltd and European Society for Clinical Nutrition and Metabolism. All rights reserved.

Mitochondrial uncoupling in skeletal muscle by UCP1 augments energy expenditure and glutathione content while mitigating ROS production.

PubMed

Adjeitey, Cyril Nii-Klu; Mailloux, Ryan J; Dekemp, Robert A; Harper, Mary-Ellen

2013-08-01

Enhancement of proton leaks in muscle tissue represents a potential target for obesity treatment. In this study, we examined the bioenergetic and physiological implications of increased proton leak in skeletal muscle. To induce muscle-specific increases in proton leak, we used mice that selectively express uncoupling protein-1 (UCP1) in skeletal muscle tissue. UCP1 expression in muscle mitochondria was ∼13% of levels in brown adipose tissue (BAT) mitochondria and caused increased GDP-sensitive proton leak. This was associated with an increase in whole body energy expenditure and a decrease in white adipose tissue content. Muscle UCP1 activity had divergent effects on mitochondrial ROS emission and glutathione levels compared with BAT. UCP1 in muscle increased total mitochondrial glutathione levels ∼7.6 fold. Intriguingly, unlike in BAT mitochondria, leak through UCP1 in muscle controlled mitochondrial ROS emission. Inhibition of UCP1 with GDP in muscle mitochondria increased ROS emission ∼2.8-fold relative to WT muscle mitochondria. GDP had no impact on ROS emission from BAT mitochondria from either genotype. Collectively, these findings indicate that selective induction of UCP1-mediated proton leak in muscle can increase whole body energy expenditure and decrease adiposity. Moreover, ectopic UCP1 expression in skeletal muscle can control mitochondrial ROS emission, while it apparently plays no such role in its endogenous tissue, brown fat.

Mitochondrial uncoupling in skeletal muscle by UCP1 augments energy expenditure and glutathione content while mitigating ROS production

PubMed Central

Adjeitey, Cyril Nii-Klu; Mailloux, Ryan J.; deKemp, Robert A.

2013-01-01

Enhancement of proton leaks in muscle tissue represents a potential target for obesity treatment. In this study, we examined the bioenergetic and physiological implications of increased proton leak in skeletal muscle. To induce muscle-specific increases in proton leak, we used mice that selectively express uncoupling protein-1 (UCP1) in skeletal muscle tissue. UCP1 expression in muscle mitochondria was ∼13% of levels in brown adipose tissue (BAT) mitochondria and caused increased GDP-sensitive proton leak. This was associated with an increase in whole body energy expenditure and a decrease in white adipose tissue content. Muscle UCP1 activity had divergent effects on mitochondrial ROS emission and glutathione levels compared with BAT. UCP1 in muscle increased total mitochondrial glutathione levels ∼7.6 fold. Intriguingly, unlike in BAT mitochondria, leak through UCP1 in muscle controlled mitochondrial ROS emission. Inhibition of UCP1 with GDP in muscle mitochondria increased ROS emission ∼2.8-fold relative to WT muscle mitochondria. GDP had no impact on ROS emission from BAT mitochondria from either genotype. Collectively, these findings indicate that selective induction of UCP1-mediated proton leak in muscle can increase whole body energy expenditure and decrease adiposity. Moreover, ectopic UCP1 expression in skeletal muscle can control mitochondrial ROS emission, while it apparently plays no such role in its endogenous tissue, brown fat. PMID:23757405

Redox environment in stem and differentiated cells: A quantitative approach.

PubMed

Lyublinskaya, O G; Ivanova, Ju S; Pugovkina, N A; Kozhukharova, I V; Kovaleva, Z V; Shatrova, A N; Aksenov, N D; Zenin, V V; Kaulin, Yu A; Gamaley, I A; Nikolsky, N N

2017-08-01

Stem cells are believed to maintain a specific intracellular redox status through a combination of enhanced removal capacity and limited production of ROS. In the present study, we challenge this assumption by developing a quantitative approach for the analysis of the pro- and antioxidant ability of human embryonic stem cells in comparison with their differentiated descendants, as well as adult stem and non-stem cells. Our measurements showed that embryonic stem cells are characterized by low ROS level, low rate of extracellular hydrogen peroxide removal and low threshold for peroxide-induced cytotoxicity. However, biochemical normalization of these parameters to cell volume/protein leads to matching of normalized values in stem and differentiated cells and shows that tested in the present study cells (human embryonic stem cells and their fibroblast-like progenies, adult mesenchymal stem cells, lymphocytes, HeLa) maintain similar intracellular redox status. Based on these observations, we propose to use ROS concentration averaged over the cell volume instead of ROS level as a measure of intracellular redox balance. We show that attempts to use ROS level for comparative analysis of redox status of morphologically different cells could lead to false conclusions. Methods for the assessment of ROS concentration based on flow cytometry analysis with the use of H 2 DCFDA dye and HyPer, genetically encoded probe for hydrogen peroxide, are discussed. Copyright © 2017 The Authors. Published by Elsevier B.V. All rights reserved.

Genotype differences in anxiety and fear learning and memory of WT and ApoE4 mice associated with enhanced generation of hippocampal reactive oxygen species.

PubMed

Villasana, Laura E; Weber, Sydney; Akinyeke, Tunde; Raber, Jacob

2016-09-01

Apolipoprotein E (apoE), involved in cholesterol and lipid metabolism, also influences cognitive function and injury repair. In humans, apoE is expressed in three isoforms. E4 is a risk factor for age-related cognitive decline and Alzheimer's disease, particularly in women. E4 might also be a risk factor for developing behavioral and cognitive changes following (56) Fe irradiation, a component of the space environment astronauts are exposed to during missions. These changes might be related to enhanced generation of reactive oxygen species (ROS). In this study, we compared the behavioral and cognitive performance of sham-irradiated and irradiated wild-type (WT) mice and mice expressing the human E3 or E4 isoforms, and assessed the generation of ROS in hippocampal slices from these mice. E4 mice had greater anxiety-like and conditioned fear behaviors than WT mice, and these genotype differences were associated with greater levels of ROS in E4 than WT mice. The greater generation of ROS in the hippocampus of E4 than WT mice might contribute to their higher anxiety levels and enhanced fear conditioning. In E4, but not WT, mice, phorbol-12-myristate-13-acetate-treated hippocampal slices showed more dihydroxy ethidium oxidation in sham-irradiated than irradiated mice and hippocampal heme oxygenase-1 levels were higher in irradiated than sham-irradiated E4 mice. Mice with apolipoprotein E4 (E4), a risk factor for Alzheimer's disease, have greater anxiety-like and conditioned fear behaviors than wild-type (WT) mice. Generation of reactive oxygen species (ROS, in red) 3 months following (56) Fe irradiation, a component of the space environment astronauts are exposed to, is more pronounced in the hippocampus of E4 than WT mice. In E4, but not WT, mice, hippocampal levels of the oxidative stress-relevant marker heme oxygenase-1 are higher in irradiated than sham-irradiated E4 mice. © 2016 International Society for Neurochemistry.

Insertion of transposon in the vicinity of SSK2 confers enhanced tolerance to furfural in Saccharomyces cerevisiae.

PubMed

Kim, Hyun-Soo; Kim, Na-Rae; Kim, Wankee; Choi, Wonja

2012-07-01

Furfural is one of the major inhibitors generated during sugar production from cellulosic materials and, as an aldehyde, inhibits various cellular activities of microorganisms used, leading to prolonged lag time during ethanologenic fermentation. Since Saccharomyces cerevisiae strains tolerant to furfural are of great economic benefit in producing bioethanol, much effort to obtain more efficient strains continues to be made. In this study, we examined the furfural tolerance of transposon mutant strains (Tn 1-5) with enhanced ethanol tolerance and found that one of them (Tn 2), in which SSK2 is downregulated at the transcriptional level, displayed improved furfural tolerance. Such phenotype was abolished by complementation of the entire open reading frame of SSK2, which encodes a mitogen-activated protein (MAP) kinase kinase kinase of the high osmolarity glycerol (HOG) signaling pathway, suggesting an inhibitory effect of SSK2 in coping with furfural stress. Tn 2 showed a significant decrease in the intracellular level of reactive oxygen species (ROS) and early and high activation of Hog1p, a MAP kinase integral to the HOG pathway in response to furfural. The transcriptional levels of CTT1 and GLR1, two of known Hog1p downstream target genes whose protein products are involved in reducing ROS, were increased by 43 % and 56 % respectively compared with a control strain, probably resulting in the ROS decrease. Tn 2 also showed a shortened lag time during fermentation in the presence of furfural, resulting from efficient conversion of furfural to non-toxic (or less toxic) furfuryl alcohol. Taken together, the enhanced furfural tolerance of Tn 2 is suggested to be conferred by the combined effect of an early event of less ROS accumulation and a late event of efficient detoxification of furfural.

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

Singlet oxygen and ROS in a new light: low-dose subcellular photodynamic treatment enhances proliferation at the single cell level.

PubMed

Blázquez-Castro, Alfonso; Breitenbach, Thomas; Ogilby, Peter R

2014-09-01

Two-photon excitation of a sensitizer with a focused laser beam was used to create a spatially-localized subcellular population of reactive oxygen species, ROS, in single HeLa cells. The sensitizer used was protoporphyrin IX, PpIX, endogenously derived from 5-aminolevulinic acid delivered to the cells. Although we infer that singlet oxygen, O2(a(1)Δg), is one ROS produced upon irradiation of PpIX under these conditions, it is possible that the superoxide ion, O2(-˙), may also play a role in this system. With a "high" dose of PpIX-sensitized ROS, the expected death of the cell was observed. However, under "low dose" conditions, clear signs of cell proliferation were observed. The present results facilitate studies of ROS-mediated signalling in imaging-based single cell experiments.

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

Protective properties of ginsenoside Rb1 against UV-B radiation-induced oxidative stress in human dermal keratinocytes.

PubMed

Oh, Sun-Joo; Kim, Kyunghoon; Lim, Chang-Jin

2015-06-01

Ginsenosides, also known as ginseng saponins, are responsible for most pharmacological effect of ginseng. Ginsenoside Rb1 (Rb1) exerts a variety of pharmacological properties, including anti-inflammatory, antistress, anti-aging and anti-neurodegenerative activities. The aim of the present work was to assess the skin anti-photoaging properties of Rb1 in human dermal keratinocyte HaCaT cells. The anti-photoaging activity was evaluated by analyzing the levels of reactive oxygen species (ROS) and matrix metalloproteinases (MMPs) as well as cell viability for HaCaT cells under UV-B irradiation. Rb1 was able to suppress the ROS levels which were elevated under UV-B irradiation, and unable to influence cellular survival in UV-B-irradiated HaCaT cells. Rb1 diminished the enhancement of MMP-2 gelatinolytic activity in conditioned medium, which corresponded with the decreased MMP-2 protein levels in both conditioned medium and cellular lysate prepared from UV-B-irradiated HaCaT cultures. Rb1 could restore the total glutathione (GSH) and superoxide dismutase (SOD) activity diminished in UV-B-irradiated HaCaT cells. Ginsenoside Rb1 possesses skin anti-photoaging properties through scavenging ROS and decreasing MMP-2 levels possibly by enhancing antioxidant activity in keratinocytes under UV-B irradiation.

Involvement of CAT in the detoxification of HT-induced ROS burst in rice anther and its relation to pollen fertility.

PubMed

Zhao, Qian; Zhou, Lujian; Liu, Jianchao; Cao, Zhenzhen; Du, Xiaoxia; Huang, Fudeng; Pan, Gang; Cheng, Fangmin

2018-05-01

HT-induced ROS burst in developing anther is closely related to the lowered CAT activity as the result of the markedly suppressed OsCATB transcript, thereby causing severe fertility injury for rice plants exposed to HT at meiosis stage. The reproductive stage of rice plants is highly sensitive to heat stress. In this paper, different rice cultivars were used to investigate the relationship of HT-induced floret sterility with reactive oxygen species (ROS) detoxification in rice anthers under well-controlled climatic conditions. Results showed that high temperature (HT) exposure significantly enhanced the ROS level and malondialdehyde (MDA) content in developing anther, and the increase in ROS amount in rice anther under HT exposure was closely associated with HT-induced decline in the activities of several antioxidant enzymes. For various antioxidant enzymes, SOD and CAT were more susceptible to the ROS burst in rice anther induced by HT exposure than APX and POD, in which SOD and CAT activity in developing anther decreased significantly by HT exposure, whereas APX activity was relatively stable among different temperature regimes. HT-induced decrease in CAT activity was attributable to the suppressed transcript of OsCATB. This occurrence was strongly responsible for HT-induced increase in ROS level and oxidative-damage in rice anther, thereby it finally caused significant reduction in pollen viability and floret fertility for the rice plants exposed to HT during meiosis. Exogenous application of 1000 µM salicylic acid (SA) may alleviate HT-induced reduction in pollen viability and floret fertility, concomitantly with the increased CAT activity and reduced ROS level in rice anther.

Quercetin manipulates the expression of genes involved in the reactive oxygen species (ROS) processin chicken heterophils.

PubMed

Nambooppha, Boondarika; Photichai, Kornravee; Wongsawan, Kanreuthai; Chuammitri, Phongsakorn

2018-06-06

Chicken heterophils generate reactive oxygen species (ROS) molecules to defend against invading pathogens. The present study examined effects of quercetin on chicken heterophils. Heterophils were stimulated with PBS, 50 μM quercetin (QH), PMA or Escherichia coli (EC) and the resulting intracellular ROS molecules were determined. Flow cytometry results showed that cells stimulated with QH, PMA and EC had a higher ROS production. Increases in intracellular ROS molecules were identified in all treatment groups by fluorescence microscopy. Determination of the ability of quercetin to manipulate mRNA expression of ROS subunits was assessed using real-time RT-PCR. Quercetin and other stimulants up-regulated the majority of genes involved in ROS production: CYBB (NOX2), NCF1 (p47 phox ), NCF2 (p67 phox ), NOX1 and RAC2. The antioxidant property of QH was explored by measuring mRNA expression of CAT and SOD1. The data indicate increased levels of CAT with all treatments; however, only QH attenuated the expression ofthe SOD1 gene. To further investigate the effects of ROS-driven inflammation or cell death, IL6, CASP8, and MCL1 genes were preferentially tested. The inflammatory gene (IL6) was profoundly down-regulated in the QH- and PMA-treated groups while EC induced a strikingly high IL6 expression level. Investigation of the known apoptotic (CASP8) and anti-apoptotic (MCL1) genes found down-regulation of CASP8 in the QH- and PMA-treated groups which were contradicted to the MCL1 gene. In conclusion, quercetin can enhance ROS production by regulating the expression of genes involved in ROS production as well as in subsequent processes.

Fetal oxidative stress mechanisms of neurodevelopmental deficits and exacerbation by ethanol and methamphetamine.

PubMed

Wells, Peter G; Bhatia, Shama; Drake, Danielle M; Miller-Pinsler, Lutfiya

2016-06-01

In utero exposure of mouse progeny to alcohol (ethanol, EtOH) and methamphetamine (METH) causes substantial postnatal neurodevelopmental deficits. One emerging pathogenic mechanism underlying these deficits involves fetal brain production of reactive oxygen species (ROS) that alter signal transduction, and/or oxidatively damage cellular macromolecules like lipids, proteins, and DNA, the latter leading to altered gene expression, likely via non-mutagenic mechanisms. Even physiological levels of fetal ROS production can be pathogenic in biochemically predisposed progeny, and ROS formation can be enhanced by drugs like EtOH and METH, via activation/induction of ROS-producing NADPH oxidases (NOX), drug bioactivation to free radical intermediates by prostaglandin H synthases (PHS), and other mechanisms. Antioxidative enzymes, like catalase in the fetal brain, while low, provide critical protection. Oxidatively damaged DNA is normally rapidly repaired, and fetal deficiencies in several DNA repair proteins, including oxoguanine glycosylase 1 (OGG1) and breast cancer protein 1 (BRCA1), enhance the risk of drug-initiated postnatal neurodevelopmental deficits, and in some cases deficits in untreated progeny, the latter of which may be relevant to conditions like autism spectrum disorders (ASD). Risk is further regulated by fetal nuclear factor erythroid 2-related factor 2 (Nrf2), a ROS-sensing protein that upregulates an array of proteins, including antioxidative enzymes and DNA repair proteins. Imbalances between conceptal pathways for ROS formation, versus those for ROS detoxification and DNA repair, are important determinants of risk. Birth Defects Research (Part C) 108:108-130, 2016. © 2016 Wiley Periodicals, Inc. © 2016 Wiley Periodicals, Inc.

Increased reactive oxygen species production during reductive stress: The roles of mitochondrial glutathione and thioredoxin reductases.

PubMed

Korge, Paavo; Calmettes, Guillaume; Weiss, James N

2015-01-01

Both extremes of redox balance are known to cause cardiac injury, with mounting evidence revealing that the injury induced by both oxidative and reductive stress is oxidative in nature. During reductive stress, when electron acceptors are expected to be mostly reduced, some redox proteins can donate electrons to O2 instead, which increases reactive oxygen species (ROS) production. However, the high level of reducing equivalents also concomitantly enhances ROS scavenging systems involving redox couples such as NADPH/NADP+ and GSH/GSSG. Here our objective was to explore how reductive stress paradoxically increases net mitochondrial ROS production despite the concomitant enhancement of ROS scavenging systems. Using recombinant enzymes and isolated permeabilized cardiac mitochondria, we show that two normally antioxidant matrix NADPH reductases, glutathione reductase and thioredoxin reductase, generate H2O2 by leaking electrons from their reduced flavoprotein to O2 when electron flow is impaired by inhibitors or because of limited availability of their natural electron acceptors, GSSG and oxidized thioredoxin. The spillover of H2O2 under these conditions depends on H2O2 reduction by peroxiredoxin activity, which may regulate redox signaling in response to endogenous or exogenous factors. These findings may explain how ROS production during reductive stress overwhelms ROS scavenging capability, generating the net mitochondrial ROS spillover causing oxidative injury. These enzymes could potentially be targeted to increase cancer cell death or modulate H2O2-induced redox signaling to protect the heart against ischemia/reperfusion damage. Copyright © 2015 Elsevier B.V. All rights reserved.

MYB and bHLH transcription factor transgenes increase anthocyanin pigmentation in petunia and lisianthus plants, and the petunia phenotypes are strongly enhanced under field conditions

PubMed Central

Schwinn, Kathy E.; Boase, Murray R.; Bradley, J. Marie; Lewis, David H.; Deroles, Simon C.; Martin, Cathie R.; Davies, Kevin M.

2014-01-01

Petunia line Mitchell [MP, Petunia axillaris × (P. axillaris × P. hybrida)] and Eustoma grandiflorum (lisianthus) plants were produced containing a transgene for over-expression of the R2R3-MYB transcription factor [TF; ROSEA1 (ROS1)] that up-regulates flavonoid biosynthesis in Antirrhinum majus. The petunia lines were also crossed with previously produced MP lines containing a Zea mays flavonoid-related basic helix-loop-helix TF transgene (LEAF COLOR, LC), which induces strong vegetative pigmentation when these 35S:LC plants are exposed to high-light levels. 35S:ROS1 lisianthus transgenics had limited changes in anthocyanin pigmentation, specifically, precocious pigmentation of flower petals and increased pigmentation of sepals. RNA transcript levels for two anthocyanin biosynthetic genes, chalcone synthase and anthocyanidin synthase, were increased in the 35S:ROS1 lisianthus petals compared to those of control lines. With MP, the 35S:ROS1 calli showed novel red pigmentation in culture, but this was generally not seen in tissue culture plantlets regenerated from the calli or young plants transferred to soil in the greenhouse. Anthocyanin pigmentation was enhanced in the stems of mature 35S:ROS1 MP plants, but the MP white-flower phenotype was not complemented. Progeny from a 35S:ROS1 × 35S:LC cross had novel pigmentation phenotypes that were not present in either parental line or MP. In particular, there was increased pigment in the petal throat region, and the anthers changed from yellow to purple pigmentation. An outdoor field trial was conducted with the 35S:ROS1, 35S:LC, 35S:ROS1 × 35S:LC and control MP lines. Field conditions rapidly induced intense foliage pigmentation in 35S:LC plants, a phenotype not observed in control MP or equivalent 35S:LC plants maintained in a greenhouse. No difference in plant stature, seed germination, or plant survival was observed between transgenic and control plants. PMID:25414715

MYB and bHLH transcription factor transgenes increase anthocyanin pigmentation in petunia and lisianthus plants, and the petunia phenotypes are strongly enhanced under field conditions.

PubMed

Schwinn, Kathy E; Boase, Murray R; Bradley, J Marie; Lewis, David H; Deroles, Simon C; Martin, Cathie R; Davies, Kevin M

2014-01-01

Petunia line Mitchell [MP, Petunia axillaris × (P. axillaris × P. hybrida)] and Eustoma grandiflorum (lisianthus) plants were produced containing a transgene for over-expression of the R2R3-MYB transcription factor [TF; ROSEA1 (ROS1)] that up-regulates flavonoid biosynthesis in Antirrhinum majus. The petunia lines were also crossed with previously produced MP lines containing a Zea mays flavonoid-related basic helix-loop-helix TF transgene (LEAF COLOR, LC), which induces strong vegetative pigmentation when these 35S:LC plants are exposed to high-light levels. 35S:ROS1 lisianthus transgenics had limited changes in anthocyanin pigmentation, specifically, precocious pigmentation of flower petals and increased pigmentation of sepals. RNA transcript levels for two anthocyanin biosynthetic genes, chalcone synthase and anthocyanidin synthase, were increased in the 35S:ROS1 lisianthus petals compared to those of control lines. With MP, the 35S:ROS1 calli showed novel red pigmentation in culture, but this was generally not seen in tissue culture plantlets regenerated from the calli or young plants transferred to soil in the greenhouse. Anthocyanin pigmentation was enhanced in the stems of mature 35S:ROS1 MP plants, but the MP white-flower phenotype was not complemented. Progeny from a 35S:ROS1 × 35S:LC cross had novel pigmentation phenotypes that were not present in either parental line or MP. In particular, there was increased pigment in the petal throat region, and the anthers changed from yellow to purple pigmentation. An outdoor field trial was conducted with the 35S:ROS1, 35S:LC, 35S:ROS1 × 35S:LC and control MP lines. Field conditions rapidly induced intense foliage pigmentation in 35S:LC plants, a phenotype not observed in control MP or equivalent 35S:LC plants maintained in a greenhouse. No difference in plant stature, seed germination, or plant survival was observed between transgenic and control plants.

Comparison of the Protective Effects of Melatonin and Silymarin Against Gentamicin-Induced Nephrotoxicity in Rats.

PubMed

Ghaznavi, Habib; Mehrzadi, Saeed; Dormanesh, Banafshe; Tabatabaei, Seyyed Mohammad Taghi Hosseini; Vahedi, Habib; Hosseinzadeh, Azam; Pazoki-Toroudi, HamidReza; Rashidian, Amir

2016-10-01

This study compared the possible protective effects of silymarin and melatonin against gentamicin (GEN)-induced nephrotoxicity in rats. Rats were allocated to 6 groups: Group I, control group; Groups II and III, administered with silymarin or melatonin; Group IV, injected with GEN; and Groups V and VI, administered with silymarin or melatonin, and then injected with GEN. Compared with the rats in the control group, all rats injected with GEN significantly presented elevated levels of serum creatinine and urea that was accompanied by an increase in relative kidney weight, increase in renal reactive oxygen species (ROS) and malondialdehyde (MDA) levels, and reduction in renal glutathione (GSH) level and superoxide dismutase (SOD) activity. Silymarin and melatonin pretreatment significantly lowered the elevated serum urea and creatinine concentration, kidney weight, and renal ROS and MDA levels. In addition, silymarin and melatonin significantly enhanced renal GSH level and SOD activity. This study indicates that silymarin and melatonin can attenuate renal injury in rats treated with GEN possibly by reducing the ROS level. © The Author(s) 2015.

Low testosterone levels are related to oxidative stress, mitochondrial dysfunction and altered subclinical atherosclerotic markers in type 2 diabetic male patients.

PubMed

Rovira-Llopis, Susana; Bañuls, Celia; de Marañon, Aranzazu M; Diaz-Morales, Noelia; Jover, Ana; Garzon, Sandra; Rocha, Milagros; Victor, Victor M; Hernandez-Mijares, Antonio

2017-07-01

Low testosterone levels in men are associated with type 2 diabetes and cardiovascular risk. However, the role of testosterone in mitochondrial function and leukocyte-endothelium interactions is unknown. Our aim was to evaluate the relationship between testosterone levels, metabolic parameters, oxidative stress, mitochondrial function, inflammation and leukocyte-endothelium interactions in type 2 diabetic patients. The study was performed in 280 male type 2 diabetic patients and 50 control subjects. Anthropometric and metabolic parameters, testosterone levels, reactive oxygen species (ROS) production, mitochondrial membrane potential, TNFα, adhesion molecules and leukocyte-endothelium cell interactions were evaluated. Testosterone levels were lower in diabetic patients. Total and mitochondrial ROS were increased and mitochondrial membrane potential, SOD and GSR expression levels were reduced in diabetic patients. TNFα, ICAM-1 and VCAM-1 levels, leukocyte rolling flux and adhesion were all enhanced in diabetic patients, while rolling velocity was reduced. Testosterone levels correlated negatively with glucose, HOMA-IR, HbA1c, triglycerides, nonHDL-c, ApoB, hs-CRP and AIP, and positively with HDL-c and ApoA1. The multivariable regression model showed that HDL-c, HOMA-IR and age were independently associated with testosterone. Furthermore, testosterone levels correlated positively with membrane potential and rolling velocity and negatively with ROS production, VCAM-1, rolling flux and adhesion. Our data highlight that low testosterone levels in diabetic men are related to impaired metabolic profile and mitochondrial function and enhanced inflammation and leukocyte-endothelium cell interaction, which leaves said patients at risk of cardiovascular events. Copyright © 2017 Elsevier Inc. All rights reserved.

Skeletal Cell Differentiation Is Enhanced by Atmospheric Dielectric Barrier Discharge Plasma Treatment

PubMed Central

Zhang, Jun; Kurpad, Deepa S.; Fridman, Gregory; Fridman, Alexander; Freeman, Theresa A.

2013-01-01

Enhancing chondrogenic and osteogenic differentiation is of paramount importance in providing effective regenerative therapies and improving the rate of fracture healing. This study investigated the potential of non-thermal atmospheric dielectric barrier discharge plasma (NT-plasma) to enhance chondrocyte and osteoblast proliferation and differentiation. Although the exact mechanism by which NT-plasma interacts with cells is undefined, it is known that during treatment the atmosphere is ionized generating extracellular reactive oxygen and nitrogen species (ROS and RNS) and an electric field. Appropriate NT-plasma conditions were determined using lactate-dehydrogenase release, flow cytometric live/dead assay, flow cytometric cell cycle analysis, and Western blots to evaluate DNA damage and mitochondrial integrity. We observed that specific NT-plasma conditions were required to prevent cell death, and that loss of pre-osteoblastic cell viability was dependent on intracellular ROS and RNS production. To further investigate the involvement of intracellular ROS, fluorescent intracellular dyes Mitosox (superoxide) and dihydrorhodamine (peroxide) were used to assess onset and duration after NT-plasma treatment. Both intracellular superoxide and peroxide were found to increase immediately post NT-plasma treatment. These increases were sustained for one hour but returned to control levels by 24 hr. Using the same treatment conditions, osteogenic differentiation by NT-plasma was assessed and compared to peroxide or osteogenic media containing β-glycerolphosphate. Although both NT-plasma and peroxide induced differentiation-specific gene expression, neither was as effective as the osteogenic media. However, treatment of cells with NT-plasma after 24 hr in osteogenic or chondrogenic media significantly enhanced differentiation as compared to differentiation media alone. The results of this study show that NT-plasma can selectively initiate and amplify ROS signaling to enhance differentiation, and suggest this technology could be used to enhance bone fusion and improve healing after skeletal injury. PMID:24349203

Skeletal cell differentiation is enhanced by atmospheric dielectric barrier discharge plasma treatment.

PubMed

Steinbeck, Marla J; Chernets, Natalie; Zhang, Jun; Kurpad, Deepa S; Fridman, Gregory; Fridman, Alexander; Freeman, Theresa A

2013-01-01

Enhancing chondrogenic and osteogenic differentiation is of paramount importance in providing effective regenerative therapies and improving the rate of fracture healing. This study investigated the potential of non-thermal atmospheric dielectric barrier discharge plasma (NT-plasma) to enhance chondrocyte and osteoblast proliferation and differentiation. Although the exact mechanism by which NT-plasma interacts with cells is undefined, it is known that during treatment the atmosphere is ionized generating extracellular reactive oxygen and nitrogen species (ROS and RNS) and an electric field. Appropriate NT-plasma conditions were determined using lactate-dehydrogenase release, flow cytometric live/dead assay, flow cytometric cell cycle analysis, and Western blots to evaluate DNA damage and mitochondrial integrity. We observed that specific NT-plasma conditions were required to prevent cell death, and that loss of pre-osteoblastic cell viability was dependent on intracellular ROS and RNS production. To further investigate the involvement of intracellular ROS, fluorescent intracellular dyes Mitosox (superoxide) and dihydrorhodamine (peroxide) were used to assess onset and duration after NT-plasma treatment. Both intracellular superoxide and peroxide were found to increase immediately post NT-plasma treatment. These increases were sustained for one hour but returned to control levels by 24 hr. Using the same treatment conditions, osteogenic differentiation by NT-plasma was assessed and compared to peroxide or osteogenic media containing β-glycerolphosphate. Although both NT-plasma and peroxide induced differentiation-specific gene expression, neither was as effective as the osteogenic media. However, treatment of cells with NT-plasma after 24 hr in osteogenic or chondrogenic media significantly enhanced differentiation as compared to differentiation media alone. The results of this study show that NT-plasma can selectively initiate and amplify ROS signaling to enhance differentiation, and suggest this technology could be used to enhance bone fusion and improve healing after skeletal injury.

Effect of density gradient centrifugation on reactive oxygen species in human semen.

PubMed

Takeshima, Teppei; Yumura, Yasushi; Kuroda, Shinnosuke; Kawahara, Takashi; Uemura, Hiroji; Iwasaki, Akira

2017-06-01

Density gradient centrifugation can separate motile sperm from immotile sperm and other cells for assisted reproduction, but may also remove antioxidants from seminal plasma, resulting in oxidative stress. Therefore, we investigated reactive oxygen species (ROS) concentrations and distribution in semen before and after density gradient centrifugation. We assessed semen volume, sperm concentration, sperm motility, and ROS levels before and after density gradient centrifugation (300 x g for 20 minutes) in 143 semen samples from 118 patients. The ROS removal rate was evaluated in ROS-positive samples and ROS formation rate in ROS-negative samples. Thirty-eight of 143 untreated samples (26.6%) were ROS-positive; sperm motility was significantly lower in these samples than in ROS-negative samples (p < 0.05). After density gradient centrifugation, only seven of the 38 ROS-positive samples (18.42%) exhibited a ROS-positive lower layer (containing motile sperm) with a ROS removal rate of 81.58%, whereas the upper layer was ROS-positive in 24 samples (63.16%). In the ROS-negative group (n = 105), ROS was detected in 19 samples after centrifugation (18.10%, ROS generation rate), of which 18 were ROS-positive only in the upper layer or interface and the other was ROS-positive in both layers. Density gradient centrifugation can separate motile sperm from immotile sperm as well as remove ROS (including newly generated ROS). This data supports the view that density gradient centrifugation can select motile spermatozoa without enhancing oxidative stress. ROS: reactive oxygen species; SOD: superoxide dismutase; GPx: glutathione peroxidase; DNA: deoxyribonucleic acid; DGC: density gradient centrifugation; IUI: intrauterine insemination; IVF: in vitro fertilization; HEPES: 4-(2-hydroxyethyl)-1-piperazineethanesulfonic acid; EDTA: ethylenediaminetetraacetic acid; HTF: HEPES-buffered human tubal fluid; IMSI: intracytoplasmic morphologically selected sperm injection; SMAS: sperm motility analyzing system; CASA: computer-assisted semen analyzer; WHO: World Health Organization.

Colloidal silver nanoparticles improve anti-leukemic drug efficacy via amplification of oxidative stress.

PubMed

Guo, Dawei; Zhang, Junren; Huang, Zhihai; Jiang, Shanxiang; Gu, Ning

2015-02-01

Recently, increased reactive oxygen species (ROS) levels and altered redox status in cancer cells have become a novel therapeutic strategy to improve cancer selectivity over normal cells. It has been known that silver nanoparticles (AgNPs) display anti-leukemic activity via ROS overproduction. Hence, we hypothesized that AgNPs could improve therapeutic efficacy of ROS-generating agents against leukemia cells. In the current study, N-(4-hydroxyphenyl)retinamide (4-HPR), a synthetic retinoid, was used as a drug model of ROS induction to investigate its synergistic effect with AgNPs. The data exhibited that AgNPs with uniform size prepared by an electrochemical method could localize in the lysosomes, mitochondria and cytoplasm of SHI-1 cells. More importantly, AgNPs together with 4-HPR could exhibit more cytotoxicity and apoptosis via overproduction of ROS in comparison with that alone. Taken together, these results reveal that AgNPs combined with ROS-generating drugs could potentially enhance therapeutic efficacy against leukemia cells, thereby providing a novel strategy for AgNPs in leukemia therapy. Copyright © 2015. Published by Elsevier B.V.

Chronic administration of thiamine pyrophosphate decreases age-related histological atrophic testicular changes and improves sexual behavior in male Wistar rats.

PubMed

Hernández-Montiel, H L; Vásquez López, C M; González-Loyola, J G; Vega-Anaya, G C; Villagrán-Herrera, M E; Gallegos-Corona, M A; Saldaña, C; Ramos Gómez, M; García Horshman, P; García Solís, P; Solís-S, J C; Robles-Osorio, M L; Ávila Morales, J; Varela-Echavarría, A; Paredes Guerrero, R

2014-06-01

Aging is a multifactorial universal process and constitutes the most important risk factor for chronic-degenerative diseases. Although it is a natural process, pathological aging arises when these changes occur quickly and the body is not able to adapt. This is often associated with the generation of reactive oxygen species (ROS), inflammation, and a decrease in the endogenous antioxidant systems, constituting a physiopathological state commonly found in chronic-degenerative diseases. At the testicular level, aging is associated with tissue atrophy, decreased steroidogenesis and spermatogenesis, and sexual behavior disorders. This situation, in addition to the elevated generation of ROS in the testicular steroidogenesis, provides a critical cellular environment causing oxidative damage at diverse cellular levels. To assess the effects of a reduction in the levels of ROS, thiamine pyrophosphate (TPP) was chronically administered in senile Wistar rats. TPP causes an activation of intermediate metabolism routes, enhancing cellular respiration and decreasing the generation of ROS. Our results show an overall decrease of atrophic histological changes linked to aging, with higher levels of serum testosterone, sexual activity, and an increase in the levels of endogenous antioxidant enzymes in TPP-treated animals. These results suggest that TPP chronic administration decreases the progression of age-related atrophic changes by improving the intermediate metabolism, and by increasing the levels of antioxidant enzymes.

Role of S100A1 in hypoxia-induced inflammatory response in cardiomyocytes via TLR4/ROS/NF-κB pathway.

PubMed

Yu, Jiangkun; Lu, Yanyu; Li, Yapeng; Xiao, Lili; Xing, Yu; Li, Yanshen; Wu, Leiming

2015-09-01

S100A1 plays a crucial role in hypoxia-induced inflammatory response in cardiomyocytes. However, the role of S100A1 in hypoxia-induced inflammatory response in cardiomyocytes is still unknown. enzyme-linked immunosorbent assay (ELISA) was performed for the determination of inflammatory cytokines. Immunocytochemistry and immunofluorescence, Western blot analysis and Real-time polymerase chain reaction (RT-PCR) were conducted to assess protein or mRNA expressions. Fluorogenic probe dihydroethidium (DHE) was used to evaluate the generation of reactive oxygen species (ROS) while Hoechst 33342 staining for apoptosis. Small interfering RNA (siRNA) for S100A1 was used to evaluate the role of S100A1. The levels of ROS and inflammatory cytokine including tumor necrosis factor (TNF)-α, interleukin (IL)-1β, IL-6 and IL-8 in H9c2 cells were increased remarkably by hypoxia. However, IL-37 protein or mRNA levels were decreased significantly. Both Toll-like receptor 4 (TLR4) inhibitor Ethyl (6R)-6-[N-(2-Chloro-4fluorophenyl)sulfamoyl]cyclohex-1-ene-1-carboxylate (TAK-242) treatment or siRNA S100A1 downregulated TLR4 expression and inflammatory cytokine level and mRNA in H9c2 cells, as well as weakening ROS and phospho-p65 Nuclear factor (NF)-κB levels. Further, S100A1 treatment significantly reduced TNF-α protein or mRNA level whereas enhanced IL-37 protein or mRNA level, and could attenuate ROS and phospho-p65 NF-κB levels. Our results demonstrate that S100A1 can regulate the inflammatory response and oxidative stress in H9C2 cells via TLR4/ROS/NF-κB pathway. These findings provide an interesting strategy for protecting cardiomyocytes from hypoxia-induced inflammatory response. © 2015 Royal Pharmaceutical Society.

[Blocking 1800 MHz mobile phone radiation-induced reactive oxygen species production and DNA damage in lens epithelial cells by noise magnetic fields].

PubMed

Wu, Wei; Yao, Ke; Wang, Kai-jun; Lu, De-qiang; He, Ji-liang; Xu, Li-hong; Sun, Wen-jun

2008-01-01

To investigate whether the exposure to the electromagnetic noise can block reactive oxygen species (ROS) production and DNA damage of lens epithelial cells induced by 1800 MHz mobile phone radiation. The DCFH-DA method and comet assay were used respectively to detect the intracellular ROS and DNA damage of cultured human lens epithelial cells induced by 4 W/kg 1800 MHz mobile phone radiation or/and 2 muT electromagnetic noise for 24 h intermittently. 1800 MHz mobile phone radiation at 4 W/kg for 24 h increased intracellular ROS and DNA damage significantly (P<0.05). However, the ROS level and DNA damage of mobile phone radiation plus noise group were not significant enhanced (P>0.05) as compared to sham exposure group. Electromagnetic noise can block intracellular ROS production and DNA damage of human lens epithelial cells induced by 1800 MHz mobile phone radiation.

Crosstalk between Oxidative Stress and SIRT1: Impact on the Aging Process

PubMed Central

Salminen, Antero; Kaarniranta, Kai; Kauppinen, Anu

2013-01-01

Increased oxidative stress has been associated with the aging process. However, recent studies have revealed that a low-level oxidative stress can even extend the lifespan of organisms. Reactive oxygen species (ROS) are important signaling molecules, e.g., being required for autophagic degradation. SIRT1, a class III protein deacetylase, is a crucial cellular survival protein, which is also involved in combatting oxidative stress. For instance, SIRT1 can stimulate the expression of antioxidants via the FoxO pathways. Moreover, in contrast to ROS, SIRT1 inhibits NF-κB signaling which is a major inducer of inflammatory responses, e.g., with inflammasome pathway. Recent studies have demonstrated that an increased level of ROS can both directly and indirectly control the activity of SIRT1 enzyme. For instance, ROS can inhibit SIRT1 activity by evoking oxidative modifications on its cysteine residues. Decreased activity of SIRT1 enhances the NF-κB signaling, which supports inflammatory responses. This crosstalk between the SIRT1 and ROS signaling provokes in a context-dependent manner a decline in autophagy and a low-grade inflammatory phenotype, both being common hallmarks of ageing. We will review the major mechanisms controlling the signaling balance between the ROS production and SIRT1 activity emphasizing that this crosstalk has a crucial role in the regulation of the aging process. PMID:23434668

Effect of hypoxia mimetic cobalt chloride on the expression of extracellular-superoxide dismutase in retinal pericytes.

PubMed

Adachi, Tetsuo; Aida, Kazunari; Nishihara, Hiroko; Kamiya, Tetsuro; Hara, Hirokazu

2011-01-01

The initial clinical stage of diabetic retinopathy (DR) is characterized by the development of intraretinal microvascular abnormalities. The increased formation of reactive oxygen species (ROS) is thought to be a key event in the pathogenesis of DR. Extracellular-superoxide dismutase (EC-SOD) is an anti-inflammatory enzyme that is distributed mainly in vascular cells and protects cells from ROS by scavenging superoxide anion. Treatment with cobalt chloride (CoCl(2)) decreased the expression of EC-SOD but not other SOD isozymes in pericytes accompanied with an increase of intracellular ROS production. Pre-treatment with N-acetylcysteine (NAC) significantly suppressed the ROS production and down-regulation of EC-SOD. We observed the activation of caspase-3 and DNA fragmentation as signs of apoptotic process by CoCl(2) treatment. In addition, these phenomena were significantly inhibited by pre-treatment with NAC. EC-SOD enhancer 4-phenyl butyric acid also suppressed the caspase-3 activation. It is known that the presence of a high level of EC-SOD throughout the vessel walls might have an important protective role against superoxide in the vascular system. The decrease in EC-SOD expression accompanied with elevation of ROS level in pericytes under hypoxia might induce and/or promote the ROS-triggered apoptosis of pericytes and the development of pathogenesis in DR.

ROS inhibitor N-acetyl-L-cysteine antagonizes the activity of proteasome inhibitors.

PubMed

Halasi, Marianna; Wang, Ming; Chavan, Tanmay S; Gaponenko, Vadim; Hay, Nissim; Gartel, Andrei L

2013-09-01

NAC (N-acetyl-L-cysteine) is commonly used to identify and test ROS (reactive oxygen species) inducers, and to inhibit ROS. In the present study, we identified inhibition of proteasome inhibitors as a novel activity of NAC. Both NAC and catalase, another known scavenger of ROS, similarly inhibited ROS levels and apoptosis associated with H₂O₂. However, only NAC, and not catalase or another ROS scavenger Trolox, was able to prevent effects linked to proteasome inhibition, such as protein stabilization, apoptosis and accumulation of ubiquitin conjugates. These observations suggest that NAC has a dual activity as an inhibitor of ROS and proteasome inhibitors. Recently, NAC was used as a ROS inhibitor to functionally characterize a novel anticancer compound, piperlongumine, leading to its description as a ROS inducer. In contrast, our own experiments showed that this compound depicts features of proteasome inhibitors including suppression of FOXM1 (Forkhead box protein M1), stabilization of cellular proteins, induction of ROS-independent apoptosis and enhanced accumulation of ubiquitin conjugates. In addition, NAC, but not catalase or Trolox, interfered with the activity of piperlongumine, further supporting that piperlongumine is a proteasome inhibitor. Most importantly, we showed that NAC, but not other ROS scavengers, directly binds to proteasome inhibitors. To our knowledge, NAC is the first known compound that directly interacts with and antagonizes the activity of proteasome inhibitors. Taken together, the findings of the present study suggest that, as a result of the dual nature of NAC, data interpretation might not be straightforward when NAC is utilized as an antioxidant to demonstrate ROS involvement in drug-induced apoptosis.

High-Dose Nicotinamide Suppresses ROS Generation and Augments Population Expansion during CD8(+) T Cell Activation.

PubMed

Choi, Ho Jin; Jang, So-Young; Hwang, Eun Seong

2015-10-01

During T cell activation, mitochondrial content increases to meet the high energy demand of rapid cell proliferation. With this increase, the level of reactive oxygen species (ROS) also increases and causes the rapid apoptotic death of activated cells, thereby facilitating T cell homeostasis. Nicotinamide (NAM) has previously been shown to enhance mitochondria quality and extend the replicative life span of human fibroblasts. In this study, we examined the effect of NAM on CD8(+) T cell activation. NAM treatment attenuated the increase of mitochondrial content and ROS in T cells activated by CD3/CD28 antibodies. This was accompanied by an accelerated and higher-level clonal expansion resulting from attenuated apoptotic death but not increased division of the activated cells. Attenuation of ROS-triggered pro-apoptotic events and upregulation of Bcl-2 expression appeared to be involved. Although cells activated in the presence of NAM exhibited compromised cytokine gene expression, our results suggest a means to augment the size of T cell expansion during activation without consuming their limited replicative potential.

Impact of trans-resveratrol-sulfates and -glucuronides on endothelial nitric oxide synthase activity, nitric oxide release and intracellular reactive oxygen species.

PubMed

Ladurner, Angela; Schachner, Daniel; Schueller, Katharina; Pignitter, Marc; Heiss, Elke H; Somoza, Veronika; Dirsch, Verena M

2014-10-17

Resveratrol (3,5,4'-trihydroxy-trans-stilbene) is a polyphenolic natural product mainly present in grape skin, berries and peanuts. In the vasculature resveratrol is thought to boost endothelial function by increasing endothelial nitric oxide synthase (eNOS) expression, by enhancing eNOS activity, and by reduction of reactive oxygen species (ROS) levels. Recent studies show that dietary resveratrol is metabolized in the liver and intestine into resveratrol-sulfate and -glucuronide derivatives questioning the relevance of multiple reported mechanistic in vitro data on resveratrol. In this study, we compare side by side different physiologically relevant resveratrol metabolites (resveratrol sulfates- and -glucuronides) and their parent compound in their influence on eNOS enzyme activity, endothelial NO release, and intracellular ROS levels. In contrast to resveratrol, none of the tested resveratrol metabolites elevated eNOS enzyme activity and endothelial NO release or affected intracellular ROS levels, leaving the possibility that not tested metabolites are active and able to explain in vivo findings.

Pioglitazone restores phagocyte mitochondrial oxidants and bactericidal capacity in Chronic Granulomatous Disease

PubMed Central

Fernandez-Boyanapalli, Ruby F.; Frasch, S. Courtney; Thomas, Stacey M.; Malcolm, Kenneth C.; Nicks, Michael; Harbeck, Ronald J.; Jakubzick, Claudia V.; Nemenoff, Raphael; Henson, Peter M.; Holland, Steven M.; Bratton, Donna L.

2015-01-01

Background Deficient production of reactive oxygen species (ROS) by the phagocyte NADPH oxidase in Chronic Granulomatous Disease (CGD) results in susceptibility to certain pathogens secondary to impaired oxidative killing and mobilization of other phagocyte defenses. PPARγ agonists including pioglitazone (Pio), approved for Type 2 diabetes therapy, alter cellular metabolism and can heighten ROS production. It was hypothesized that Pio treatment of gp91phox−/− mice, a murine model of human CGD, would enhance phagocyte oxidant production and killing of S. aureus, a significant pathogen in this disorder. Objectives We sought to determine if Pio treatment of gp91phox−/− mice enhanced phagocyte oxidant production and host defense. Methods Wild type (WT) and gp91phox−/− mice were treated with the PPARγ agonist Pio, and phagocyte ROS and killing of S. aureus investigated. Results As demonstrated by three different ROS sensing probes, short-term treatment of gp91phox−/− mice with Pio enhanced stimulated ROS production in neutrophils and monocytes from blood and neutrophils and inflammatory macrophages recruited to tissues. Mitochondria were identified as the source of ROS (mtROS). Findings were replicated in human CGD monocytes following ex vivo Pio treatment. Importantly, while mtROS were deficient in gp91phox−/− phagocytes, their restoration with treatment significantly enabled killing of S. aureus both ex vivo and in vivo. Conclusions Together, the data support the hypothesis that signaling from the NADPH oxidase under normal circumstances governs phagocyte mtROS production, and that such signaling is lacking in the absence of a functioning phagocyte oxidase. PPARγ agonism appears to bypass the need for the NADPH oxidase for enhanced mtROS production and partially restores host defense in CGD. PMID:25498313

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

Sarwar, Tarique; Zafaryab, Md; Husain, Mohammed Amir

Ferulic acid (FA) is a plant polyphenol showing diverse therapeutic effects against cancer, diabetes, cardiovascular and neurodegenerative diseases. FA is a known antioxidant at lower concentrations, however at higher concentrations or in the presence of metal ions such as copper, it may act as a pro-oxidant. It has been reported that copper levels are significantly raised in different malignancies. Cancer cells are under increased oxidative stress as compared to normal cells. Certain therapeutic substances like polyphenols can further increase this oxidative stress and kill cancer cells without affecting the proliferation of normal cells. Through various in vitro experiments we havemore » shown that the pro-oxidant properties of FA are enhanced in the presence of copper. Comet assay demonstrated the ability of FA to cause oxidative DNA breakage in human peripheral lymphocytes which was ameliorated by specific copper-chelating agent such as neocuproine and scavengers of ROS. This suggested the mobilization of endogenous copper in ROS generation and consequent DNA damage. These results were further validated through cytotoxicity experiments involving different cell lines. Thus, we conclude that such a pro-oxidant mechanism involving endogenous copper better explains the anticancer activities of FA. This would be an alternate non-enzymatic, and copper-mediated pathway for the cytotoxic activities of FA where it can selectively target cancer cells with elevated levels of copper and ROS. - Highlights: • Pro-oxidant properties of ferulic acid are enhanced in presence of copper. • Ferulic acid causes oxidative DNA damage in lymphocytes as observed by comet assay. • DNA damage was ameliorated by copper chelating agent neocuproine and ROS scavengers. • Endogenous copper is involved in ROS generation causing DNA damage. • Ferulic acid exerts cancer cell specific cytotoxicity as observed by MTT assay.« less

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.

Antioxidant effects of Cirsium setidens extract on oxidative stress in human mesenchymal stem cells.

PubMed

Lee, Jun Hee; Jung, Ho Kyung; Han, Yong-Seok; Yoon, Yeo Min; Yun, Chul Won; Sun, Hwa Yeon; Cho, Hyun Woo; Lee, Sang Hun

2016-10-01

Human mesenchymal stem cells (MSCs) may be used in cell-based therapy to promote neovascularization for the treatment of ischemic diseases. However, high levels of reactive oxygen species (ROS) derived from the pathophysiological ischemic environment induce senescence and apoptosis of MSCs, resulting in reduced functionality and defective neovascularization. Therefore, the present study aimed to determine the protective effects of Cirsium setidens, a natural product, on oxidative stress‑induced apoptosis in MSCs. The present study investigated for the change of ROS levels in MSCs using ROS assays. In addition, cell viability determined by MTT and TUNEL assays. Western blot analysis was performed to investigate the change of apoptosis‑associated proteins in MSCs. Treatment of MSCs with hydrogen peroxide (H2O2; 200 µM) significantly increased intracellular ROS levels and cell death; however, pretreatment with C. setidens (100 µg/ml) suppressed H2O2‑induced ROS generation and increased the survival of MSCs. H2O2‑induced ROS production increased the levels of phosphorylated‑p38 mitogen activated protein kinase, c‑Jun N‑terminal kinase, ataxia telangiectasia mutated and p53; these increases were inhibited by pretreatment with C. setidens. In addition, C. setidens inhibited ROS‑induced apoptosis of MSCs by increasing the expression levels of the anti‑apoptotic protein B‑cell lymphoma 2 (BCL‑2), and decreasing the expression levels of the proapoptotic protein BCL‑2‑associated X protein. These findings indicated that pretreatment of MSCs with C. setidens may prevent ROS‑induced oxidative injury by regulating the oxidative stress‑associated signaling pathway, and suppressing the apoptosis‑associated signal pathway. Therefore, C. setidens may be developed as a beneficial broad‑spectrum agent for enhancing the effectiveness of MSC transplantation in the treatment of ischemic diseases.

Emodin enhances cisplatin-induced cytotoxicity in human bladder cancer cells through ROS elevation and MRP1 downregulation.

PubMed

Li, Xinxing; Wang, Haolu; Wang, Juan; Chen, Yuying; Yin, Xiaobin; Shi, Guiying; Li, Hui; Hu, Zhiqian; Liang, Xiaowen

2016-08-02

Chemoresistance is one of the most leading causes for tumor progression and recurrence of bladder cancer. Reactive oxygen species (ROS) plays a key role in the chemosensitivity of cancer cells. In the present study, emodin (1,3,8-trihydroxy-6-methylanthraquinone) was applied as a ROS generator in combination with cisplatin in T24 and J82 human bladder cancer cells. Cell viability and apoptosis rate of different treatment groups were detected by 3-(4,5-dimethylthiazol-2-yl)-2, 5-diphenyltetrazolium bromide (MTT) and flow cytometry (FCM). The expression of transporters was measured at both the transcription and translation levels using PCR and western blotting. In vitro findings were confirmed by in vivo experiments using tumor-bearing mice. The expression of multidrug resistance-associated protein 1 (MRP1) in tumour tissue was measured using immunohistochemistry and side effects of the emodin/cisplatin co-treatment were investigated by histological examination. Emodin increased the cellular ROS level and effectively enhanced the cisplatin-induced cytotoxicity of T24 and J82 human bladder cancer cells through decreasing glutathione-cisplatin (GSH-cisplatin) conjugates. It blocked the chemoresistance of T24 and J82 cells to cisplatin through suppressing the expression of MRP1. This effect was specific in T24 and J82 cells but not in HCV-29 normal bladder epithelial cells. Consistent with in vitro experiments, emodin/cisplatin co-treatment increased the cell apoptosis and repressed the MRP1 expression in xenograft tumors, and without obvious systemic toxicity. This study revealed that emodin could increase the cisplatin-induced cytotoxicity against T24 and J82 cells via elevating the cellular ROS level and downregulating MRP1 expression. We suggest that emodin could serve as an effective adjuvant agent for the cisplatin-based chemotherapy of bladder cancer.

IGF-I enhances cellular senescence via the reactive oxygen species-p53 pathway

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

Handayaningsih, Anastasia-Evi; Takahashi, Michiko; Fukuoka, Hidenori

2012-08-24

Highlights: Black-Right-Pointing-Pointer Cellular senescence plays an important role in tumorigenesis and aging process. Black-Right-Pointing-Pointer We demonstrated IGF-I enhanced cellular senescence in primary confluent cells. Black-Right-Pointing-Pointer IGF-I enhanced cellular senescence in the ROS and p53-dependent manner. Black-Right-Pointing-Pointer These results may explain the underlying mechanisms of IGF-I involvement in tumorigenesis and in regulation of aging. -- Abstract: Cellular senescence is characterized by growth arrest, enlarged and flattened cell morphology, the expression of senescence-associated {beta}-galactosidase (SA-{beta}-gal), and by activation of tumor suppressor networks. Insulin-like growth factor-I (IGF-I) plays a critical role in cellular growth, proliferation, tumorigenesis, and regulation of aging. In the presentmore » study, we show that IGF-I enhances cellular senescence in mouse, rat, and human primary cells in the confluent state. IGF-I induced expression of a DNA damage marker, {gamma}H2AX, the increased levels of p53 and p21 proteins, and activated SA-{beta}-gal. In the confluent state, an altered downstream signaling of IGF-I receptor was observed. Treatment with a reactive oxygen species (ROS) scavenger, N-acetylcystein (NAC) significantly suppressed induction of these markers, indicating that ROS are involved in the induction of cellular senescence by IGF-I. In p53-null mouse embryonic fibroblasts, the IGF-I-induced augmentation of SA-{beta}-gal and p21 was inhibited, demonstrating that p53 is required for cellular senescence induced by IGF-I. Thus, these data reveal a novel pathway whereby IGF-I enhances cellular senescence in the ROS and p53-dependent manner and may explain the underlying mechanisms of IGF-I involvement in tumorigenesis and in regulation of aging.« less

Hydroxychavicol, a betel leaf component, inhibits prostate cancer through ROS-driven DNA damage and apoptosis.

PubMed

Gundala, Sushma Reddy; Yang, Chunhua; Mukkavilli, Rao; Paranjpe, Rutugandha; Brahmbhatt, Meera; Pannu, Vaishali; Cheng, Alice; Reid, Michelle D; Aneja, Ritu

2014-10-01

Dietary phytochemicals are excellent ROS-modulating agents and have been shown to effectively enhance ROS levels beyond toxic threshold in cancer cells to ensure their selective killing while leaving normal cells unscathed. Here we demonstrate that hydroxychavicol (HC), extracted and purified from Piper betel leaves, significantly inhibits growth and proliferation via ROS generation in human prostate cancer, PC-3 cells. HC perturbed cell-cycle kinetics and progression, reduced clonogenicity and mediated cytotoxicity by ROS-induced DNA damage leading to activation of several pro-apoptotic molecules. In addition, HC treatment elicited a novel autophagic response as evidenced by the appearance of acidic vesicular organelles and increased expression of autophagic markers, LC3-IIb and beclin-1. Interestingly, quenching of ROS with tiron, an antioxidant, offered significant protection against HC-induced inhibition of cell growth and down regulation of caspase-3, suggesting the crucial role of ROS in mediating cell death. The collapse of mitochondrial transmembrane potential by HC further revealed the link between ROS generation and induction of caspase-mediated apoptosis in PC-3 cells. Our data showed remarkable inhibition of prostate tumor xenografts by ~72% upon daily oral administration of 150mg/kg bw HC by quantitative tumor volume measurements and non-invasive real-time bioluminescent imaging. HC was well-tolerated at this dosing level without any observable toxicity. This is the first report to demonstrate the anti-prostate cancer efficacy of HC in vitro and in vivo, which is perhaps attributable to its selective prooxidant activity to eliminate cancer cells thus providing compelling grounds for future preclinical studies to validate its potential usefulness for prostate cancer management. Copyright © 2014 Elsevier Inc. All rights reserved.

Inhibition of biphasic ethylene production enhances tolerance to abiotic stress by reducing the accumulation of reactive oxygen species in Nicotiana tabacum.

PubMed

Wi, Soo Jin; Jang, Su Jin; Park, Ky Young

2010-07-01

Reactive oxygen species (ROS), such as H(2)O(2), are important plant cell signaling molecules involved in responses to biotic and abiotic stresses and in developmental and physiological processes. Despite the well-known physiological functions of ethylene production and stress signaling via ROS during stresses, whether ethylene acts alone or in conjunction with ROS has not yet been fully elucidated. Therefore, we investigated the relationship between ethylene production and ROS accumulation during the response to abiotic stress. We used three independent transgenic tobacco lines, CAS-AS-2, -3 and -4, in which an antisense transcript of the senescence-related ACC synthase (ACS) gene from carnation flower (CARACC, Gen-Bank accession No. M66619) was expressed heterologously. Biphasic ethylene biosynthesis was reduced significantly in these transgenic plants, with or without H(2)O(2) treatment. These plants exhibited significantly reduced H(2)O(2)-induced gene-specific expression of ACS members, which were regulated in a time-dependent manner. The higher levels of NtACS1 expression in wild-type plants led to a second peak in ethylene production, which resulted in a more severe level of necrosis and cell death, as determined by trypan blue staining. In the transgenic lines, upregulated transcription of CAB, POR1 and RbcS resulted in increased photosynthetic performance following salt stress. This stress tolerance of H(2)O(2)-treated transgenic plants resulted from reduced ethylene biosynthesis, which decreased ROS accumulation via increased gene expression and activity of ROS-detoxifying enzymes, including MnSOD, CuZnSOD, and catalase. Therefore, it is suggested that ethylene plays a potentially critical role as an amplifier for ROS accumulation, implying a synergistic effect between biosynthesis of ROS and ethylene.

Antioxidative capacity and enzyme activity in Haematococcus pluvialis cells exposed to superoxide free radicals

NASA Astrophysics Data System (ADS)

Liu, Jianguo; Zhang, Xiaoli; Sun, Yanhong; Lin, Wei

2010-01-01

The antioxidative capacity of astaxanthin and enzyme activity of reactive oxygen eliminating enzymes such as superoxide dismutase (SOD), peroxidase (POD), catalase (CAT) and ascorbate peroxidase (APX) were studied in three cell types of Haematococcus pluvialis exposed to high concentrations of a superoxide anion radical (O{2/-}). The results show that defensive enzymes and astaxanthin-related mechanisms were both active in H. pluvialis during exposure to reactive oxygen species (ROS) such as O{2/-}. Astaxanthin reacted with ROS much faster than did the protective enzymes, and had the strongest antioxidative capacity to protect against lipid peroxidation. The defensive mechanisms varied significantly between the three cell types and were related to the level of astaxanthin that had accumulated in those cells. Astaxanthin-enriched red cells had the strongest antioxidative capacity, followed by brown cells, and astaxanthin-deficient green cells. Although there was no significant increase in expression of protective enzymes, the malondialdehyde (MDA) content in red cells was sustained at a low level because of the antioxidative effect of astaxanthin, which quenched O{2/-} before the protective enzymes could act. In green cells, astaxanthin is very low or absent; therefore, scavenging of ROS is inevitably reliant on antioxidative enzymes. Accordingly, in green cells, these enzymes play the leading role in scavenging ROS, and the expression of these enzymes is rapidly increased to reduce excessive ROS. However, because ROS were constantly increased in this study, the enhance enzyme activity in the green cells was not able to repair the ROS damage, leading to elevated MDA content. Of the four defensive enzymes measured in astaxanthin-deficient green cells, SOD eliminates O{2/-}, POD eliminates H2O2, which is a by-product of SOD activity, and APX and CAT are then initiated to scavenge excessive ROS.

Hydroxychavicol, a betel leaf component, inhibits prostate cancer through ROS-driven DNA damage and apoptosis

PubMed Central

Gundala, Sushma Reddy; Yang, Chunhua; Mukkavilli, Rao; Paranjpe, Rutugandha; Brahmbhatt, Meera; Pannu, Vaishali; Cheng, Alice; Reid, Michelle D.; Aneja, Ritu

2015-01-01

Dietary phytochemicals are excellent ROS-modulating agents and have been shown to effectively enhance ROS levels beyond toxic threshold in cancer cells to ensure their selective killing while leaving normal cells unscathed. Here we demonstrate that hydroxychavicol (HC), extracted and purified from Piper betel leaves, significantly inhibits growth and proliferation via ROS generation in human prostate cancer, PC-3 cells. HC perturbed cell-cycle kinetics and progression, reduced clonogenicity and mediated cytotoxicity by ROS-induced DNA damage leading to activation of several pro-apoptotic molecules. In addition, HC treatment elicited a novel autophagic response as evidenced by the appearance of acidic vesicular organelles and increased expression of autophagic markers, LC3-IIb and beclin-1. Interestingly, quenching of ROS with tiron, an antioxidant, offered significant protection against HC-induced inhibition of cell growth and down regulation of caspase-3, suggesting the crucial role of ROS in mediating cell death. The collapse of mitochondrial transmembrane potential by HC further revealed the link between ROS generation and induction of caspase-mediated apoptosis in PC-3 cells. Our data showed remarkable inhibition of prostate tumor xenografts by ~72% upon daily oral administration of 150 mg/kg bw HC by quantitative tumor volume measurements and non-invasive real-time bioluminescent imaging. HC was well-tolerated at this dosing level without any observable toxicity. This is the first report to demonstrate the anti-prostate efficacy of HC in vitro and in vivo, which is perhaps attributable to its selective prooxidant activity to eliminate cancer cells thus providing compelling grounds for future preclinical studies to validate its potential usefulness for prostate cancer management. PMID:25064160

Nmdmc overexpression extends Drosophila lifespan and reduces levels of mitochondrial reactive oxygen species

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

Yu, Suyeun; Jang, Yeogil; Paik, Donggi

NAD-dependent methylenetetrahydrofolate dehydrogenase-methenyltetrahydrofolate cyclohydrolase (NMDMC) is a bifunctional enzyme involved in folate-dependent metabolism and highly expressed in rapidly proliferating cells. However, Nmdmc physiological roles remain unveiled. We found that ubiquitous Nmdmc overexpression enhanced Drosophila lifespan and stress resistance. Interestingly, Nmdmc overexpression in the fat body was sufficient to increase lifespan and tolerance against oxidative stress. In addition, these conditions coincided with significant decreases in the levels of mitochondrial ROS and Hsp22 as well as with a significant increase in the copy number of mitochondrial DNA. These results suggest that Nmdmc overexpression should be beneficial for mitochondrial homeostasis and increasing lifespan.more » - Highlights: • Ubiquitous Nmdmc overexpression enhanced lifespan and stress tolerance. • Nmdmc overexpression in the fat body extended longevity. • Fat body-specific Nmdmc overexpression increased oxidative stress resistance. • Nmdmc overexpression decreased Hsp22 transcript levels and ROS. • Nmdmc overexpression increased mitochondrial DNA copy number.« less

Effects of chlorogenic acid on capacity of free radicals scavenging and proteomic changes in postharvest fruit of nectarine.

PubMed

Xi, Yu; Jiao, Wenxiao; Cao, Jiankang; Jiang, Weibo

2017-01-01

To study how chlorogenic acid affects changes of reactive oxygen species (ROS) and the proteins involved in ROS scavenging of nectarine during storage time, the fruits were treated with chlorogenic acid (CHA) then stored at 25°C for further studies. The CHA-treatment significantly reduced O2-· production rate, H2O2 content, and membrane permeability of nectarine fruit during storage. The key proteins related the nectarine fruit senescence during storage were identified by two-dimensional electrophoresis and MALDI-TOF/TOF. Level and enzymatic activity of peroxidase were reduced, while both the protein levels and the enzymatic activities of superoxide dismutase, glutathione reductase, glutathione-s-transferase and monodehydroascorbate reductase were enhanced in nectarine fruit treated with CHA. In addition, levels of several pathogen-related proteins were also enhanced by CHA-treatment. Taking together, the present study showed that CHA could influence changes in defense related proteins and reduced oxidative damage in nectarine fruit during postharvest ripening.

High hydrostatic pressure leads to free radicals accumulation in yeast cells triggering oxidative stress.

PubMed

Bravim, Fernanda; Mota, Mainã M; Fernandes, A Alberto R; Fernandes, Patricia M B

2016-08-01

Saccharomyces cerevisiae is a unicellular organism that during the fermentative process is exposed to a variable environment; hence, resistance to multiple stress conditions is a desirable trait. The stress caused by high hydrostatic pressure (HHP) in S. cerevisiae resembles the injuries generated by other industrial stresses. In this study, it was confirmed that gene expression pattern in response to HHP displays an oxidative stress response profile which is expanded upon hydrostatic pressure release. Actually, reactive oxygen species (ROS) concentration level increased in yeast cells exposed to HHP treatment and an incubation period at room pressure led to a decrease in intracellular ROS concentration. On the other hand, ethylic, thermic and osmotic stresses did not result in any ROS accumulation in yeast cells. Microarray analysis revealed an upregulation of genes related to methionine metabolism, appearing to be a specific cellular response to HHP, and not related to other stresses, such as heat and osmotic stresses. Next, we investigated whether enhanced oxidative stress tolerance leads to enhanced tolerance to HHP stress. Overexpression of STF2 is known to enhance tolerance to oxidative stress and we show that it also leads to enhanced tolerance to HHP stress. © FEMS 2016. All rights reserved. For permissions, please e-mail: journals.permissions@oup.com.

The calcium sensor GhCaM7 promotes cotton fiber elongation by modulating reactive oxygen species (ROS) production.

PubMed

Tang, Wenxin; Tu, Lili; Yang, Xiyan; Tan, Jiafu; Deng, Fenglin; Hao, Juan; Guo, Kai; Lindsey, Keith; Zhang, Xianlong

2014-04-01

Fiber elongation is the key determinant of fiber quality and output in cotton (Gossypium hirsutum). Although expression profiling and functional genomics provide some data, the mechanism of fiber development is still not well understood. Here, a gene encoding a calcium sensor, GhCaM7, was isolated based on its high expression level relative to other GhCaMs in fiber cells at the fast elongation stage. The level of expression of GhCaM7 in the wild-type and the fuzzless/lintless mutant correspond to the presence and absence, respectively, of fiber initials. Overexpressing GhCaM7 promotes early fiber elongation, whereas GhCaM7 suppression by RNAi delays fiber initiation and inhibits fiber elongation. Reactive oxygen species (ROS) play important roles in early fiber development. ROS induced by exogenous hydrogen peroxide (H2 O2 ) and Ca(2+) starvation promotes early fiber elongation. GhCaM7 overexpression fiber cells show increased ROS concentrations compared with the wild-type, while GhCaM7 RNAi fiber cells have reduced concentrations. Furthermore, we show that H2 O2 enhances Ca(2+) influx into the fiber and feedback-regulates the expression of GhCaM7. We conclude that GhCaM7, Ca(2+) and ROS are three important regulators involved in early fiber elongation. GhCaM7 might modulate ROS production and act as a molecular link between Ca(2+) and ROS signal pathways in early fiber development. © 2014 The Authors. New Phytologist © 2014 New Phytologist Trust.

MRP8/14 Enhances Corneal Susceptibility to Pseudomonas aeruginosa Infection by Amplifying Inflammatory Responses

PubMed Central

Deng, Qiuchan; Sun, Mingxia; Yang, Kun; Zhu, Min; Chen, Kang; Yuan, Jin; Wu, Minhao; Huang, Xi

2013-01-01

Purpose. We explored the role of myeloid-related protein 8 and 14 (MRP8/14) in Pseudomonas aeruginosa (PA) keratitis. Methods. MRP8/14 mRNA levels in human corneal scrapes and mouse corneas infected by PA were tested using real-time PCR. MRP8/14 protein expression in C57BL/6 (B6) corneas was confirmed using Western blot assay and immunohistochemistry. B6 mice were injected subconjunctivally with siRNA for MRP8/14, and then infected with PA. Bacterial plate counts and myeloperoxidase assays were used to determine the bacterial load and polymorphonuclear neutrophil (PMN) infiltration in infected B6 corneas. Pro-inflammatory cytokine levels in vivo and in vitro were examined with PCR and ELISA. In murine macrophage-like RAW264.7 cells, phagocytosis and bacterial killing were assessed using plate count assays, and reactive oxygen species (ROS) and nitric oxide (NO) levels were tested with flow cytometry and Griess assay, respectively. Results. MRP8/14 expression levels were increased significantly in human corneal scrapes and B6 corneas after PA infection. Silencing of MRP8/14 in B6 corneas significantly reduced the severity of corneal disease, bacterial clearance, PMN infiltration, and pro-inflammatory cytokine expression after PA infection. In vitro studies demonstrated further that silencing of MRP8/14 suppressed pro-inflammatory cytokine production, bacterial killing, and ROS production, but not phagocytosis or NO production. Conclusions. Our study demonstrated a dual role for MRP8/14 in bacterial keratitis. Although MRP8/14 promotes bacterial clearance by enhancing ROS production, it functions more importantly as an inflammatory amplifier at the ocular surface by enhancing pro-inflammatory cytokine expression, thus contributing to the corneal susceptibility. PMID:23299480

Precise Regulation of miR-210 Is Critical for the Cellular Homeostasis Maintenance and Transplantation Efficacy Enhancement of Mesenchymal Stem Cells in Acute Liver Failure Therapy.

PubMed

Liu, Yingxia; Xiong, Yongjia; Xing, Feiyue; Gao, Hao; Wang, Xiaogang; He, Liumin; Ren, Chaoran; Liu, Lei; So, Kwok-Fai; Xiao, Jia

2017-05-09

Stem cell transplantation is a promising clinical strategy to cure acute liver failure. However, a low cell survival ratio after transplantation significantly impairs its therapeutic efficacy. This is partly due to insufficient resistance of transplanted stem cells to severe oxidative and inflammatory stress at the injury sites. In the current study, we demonstrated that a small molecule zeaxanthin dipalmitate (ZD) could enhance the defensive abilities against adverse stresses of human adipose-derived mesenchymal stem cells (hADMSCs) in vitro and increase their therapeutic outcomes of acute liver failure after transplantation in vivo. Treatment with ZD dramatically improved cell survival and suppressed apoptosis, inflammation, and reactive oxygen species (ROS) production of hADMSCs through the PKC/Raf-1/MAPK/NF-κB pathway to maintain a reasonably high expression level of microRNA-210 (miR-210). The regulation loop between miR-210 and cellular/mitochondrial ROS production was found to be linked by the ROS inhibitor iron-sulfur cluster assembly proteins (ISCU). Pretreatment with ZD and stable knockdown of miR-210 significantly improved and impaired the stem cell transplantation efficacy through the alteration of hepatic cell expansion and injury amelioration, respectively. Vehicle treatment with ZD did not pose any adverse effect on cell homeostasis or healthy animal. In conclusion, elevating endogenous antioxidant level of hADMSCs with ZD significantly enhances their hepatic tissue-repairing capabilities. Maintenance of a physiological level of miR-210 is critical for hADMSC homeostasis.

Activation of apurinic/apyrimidinic endonuclease in human cells by reactive oxygen species and its correlation with their adaptive response to genotoxicity of free radicals

PubMed Central

Ramana, Chilakamarti V.; Boldogh, Istvan; Izumi, Tadahide; Mitra, Sankar

1998-01-01

Apurinic/apyrimidinic (AP) endonuclease (APE; EC 4.2.99.18) plays a central role in repair of DNA damage due to reactive oxygen species (ROS) because its DNA 3′-phosphoesterase activity removes 3′ blocking groups in DNA that are generated by DNA glycosylase/AP-lyases during removal of oxidized bases and by direct ROS reaction with DNA. The major human APE (APE-1) gene is activated selectively by sublethal levels of a variety of ROS and ROS generators, including ionizing radiation, but not by other genotoxicants—e.g., UV light and alkylating agents. Increased expression of APE mRNA and protein was observed both in the HeLa S3 tumor line and in WI 38 primary fibroblasts, and it was accompanied by translocation of the endonuclease to the nucleus. ROS-treated cells showed a significant increase in resistance to the cytotoxicity of such ROS generators as H2O2 and bleomycin, but not to UV light. This “adaptive response” appears to result from enhanced repair of cytotoxic DNA lesions due to an increased activity of APE-1, which may be limiting in the base excision repair process for ROS-induced toxic lesions. PMID:9560228

Glutathionylation state of uncoupling protein-2 and the control of glucose-stimulated insulin secretion.

PubMed

Mailloux, Ryan J; Fu, Accalia; Robson-Doucette, Christine; Allister, Emma M; Wheeler, Michael B; Screaton, Robert; Harper, Mary-Ellen

2012-11-16

The role of reactive oxygen species (ROS) in glucose-stimulated insulin release remains controversial because ROS have been shown to both amplify and impede insulin release. In regard to preventing insulin release, ROS activates uncoupling protein-2 (UCP2), a mitochondrial inner membrane protein that negatively regulates glucose-stimulated insulin secretion (GSIS) by uncoupling oxidative phosphorylation. With our recent discovery that the UCP2-mediated proton leak is modulated by reversible glutathionylation, a process responsive to small changes in ROS levels, we resolved to determine whether glutathionylation is required for UCP2 regulation of GSIS. Using Min6 cells and pancreatic islets, we demonstrate that induction of glutathionylation not only deactivates UCP2-mediated proton leak but also enhances GSIS. Conversely, an increase in mitochondrial matrix ROS was found to deglutathionylate and activate UCP2 leak and impede GSIS. Glucose metabolism also decreased the total amount of cellular glutathionylated proteins and increased the cellular glutathione redox ratio (GSH/GSSG). Intriguingly, the provision of extracellular ROS (H(2)O(2), 10 μM) amplified GSIS and also activated UCP2. Collectively, our findings indicate that the glutathionylation status of UCP2 contributes to the regulation of GSIS, and different cellular sites and inducers of ROS can have opposing effects on GSIS, perhaps explaining some of the controversy surrounding the role of ROS in GSIS.

Glutathionylation State of Uncoupling Protein-2 and the Control of Glucose-stimulated Insulin Secretion*

PubMed Central

Mailloux, Ryan J.; Fu, Accalia; Robson-Doucette, Christine; Allister, Emma M.; Wheeler, Michael B.; Screaton, Robert; Harper, Mary-Ellen

2012-01-01

The role of reactive oxygen species (ROS) in glucose-stimulated insulin release remains controversial because ROS have been shown to both amplify and impede insulin release. In regard to preventing insulin release, ROS activates uncoupling protein-2 (UCP2), a mitochondrial inner membrane protein that negatively regulates glucose-stimulated insulin secretion (GSIS) by uncoupling oxidative phosphorylation. With our recent discovery that the UCP2-mediated proton leak is modulated by reversible glutathionylation, a process responsive to small changes in ROS levels, we resolved to determine whether glutathionylation is required for UCP2 regulation of GSIS. Using Min6 cells and pancreatic islets, we demonstrate that induction of glutathionylation not only deactivates UCP2-mediated proton leak but also enhances GSIS. Conversely, an increase in mitochondrial matrix ROS was found to deglutathionylate and activate UCP2 leak and impede GSIS. Glucose metabolism also decreased the total amount of cellular glutathionylated proteins and increased the cellular glutathione redox ratio (GSH/GSSG). Intriguingly, the provision of extracellular ROS (H2O2, 10 μm) amplified GSIS and also activated UCP2. Collectively, our findings indicate that the glutathionylation status of UCP2 contributes to the regulation of GSIS, and different cellular sites and inducers of ROS can have opposing effects on GSIS, perhaps explaining some of the controversy surrounding the role of ROS in GSIS. PMID:23035124

Glutathione depletion prevents diet-induced obesity and enhances insulin sensitivity.

PubMed

Findeisen, Hannes M; Gizard, Florence; Zhao, Yue; Qing, Hua; Jones, Karrie L; Cohn, Dianne; Heywood, Elizabeth B; Bruemmer, Dennis

2011-12-01

Excessive accumulation of reactive oxygen species (ROS) in adipose tissue has been implicated in the development of insulin resistance and type 2 diabetes. However, emerging evidence suggests a physiologic role of ROS in cellular signaling and insulin sensitivity. In this study, we demonstrate that pharmacologic depletion of the antioxidant glutathione in mice prevents diet-induced obesity, increases energy expenditure and locomotor activity, and enhances insulin sensitivity. These observations support a beneficial role of ROS in glucose homeostasis and warrant further research to define the regulation of metabolism and energy balance by ROS.

Hyperoxia activates ATM independent from mitochondrial ROS and dysfunction.

PubMed

Resseguie, Emily A; Staversky, Rhonda J; Brookes, Paul S; O'Reilly, Michael A

2015-08-01

High levels of oxygen (hyperoxia) are often used to treat individuals with respiratory distress, yet prolonged hyperoxia causes mitochondrial dysfunction and excessive reactive oxygen species (ROS) that can damage molecules such as DNA. Ataxia telangiectasia mutated (ATM) kinase is activated by nuclear DNA double strand breaks and delays hyperoxia-induced cell death through downstream targets p53 and p21. Evidence for its role in regulating mitochondrial function is emerging, yet it has not been determined if mitochondrial dysfunction or ROS activates ATM. Because ATM maintains mitochondrial homeostasis, we hypothesized that hyperoxia induces both mitochondrial dysfunction and ROS that activate ATM. In A549 lung epithelial cells, hyperoxia decreased mitochondrial respiratory reserve capacity at 12h and basal respiration by 48 h. ROS were significantly increased at 24h, yet mitochondrial DNA double strand breaks were not detected. ATM was not required for activating p53 when mitochondrial respiration was inhibited by chronic exposure to antimycin A. Also, ATM was not further activated by mitochondrial ROS, which were enhanced by depleting manganese superoxide dismutase (SOD2). In contrast, ATM dampened the accumulation of mitochondrial ROS during exposure to hyperoxia. Our findings suggest that hyperoxia-induced mitochondrial dysfunction and ROS do not activate ATM. ATM more likely carries out its canonical response to nuclear DNA damage and may function to attenuate mitochondrial ROS that contribute to oxygen toxicity. Copyright © 2015 The Authors. Published by Elsevier B.V. All rights reserved.

Gingerol sensitizes TRAIL-induced apoptotic cell death of glioblastoma cells

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

Lee, Dae-Hee, E-mail: leedneo@gmail.com; Kim, Dong-Wook; Jung, Chang-Hwa

Glioblastoma multiforme (GBM) is the most lethal and aggressive astrocytoma of primary brain tumors in adults. Although there are many clinical trials to induce the cell death of glioblastoma cells, most glioblastoma cells have been reported to be resistant to TRAIL-induced apoptosis. Here, we showed that gingerol as a major component of ginger can induce TRAIL-mediated apoptosis of glioblastoma. Gingerol increased death receptor (DR) 5 levels in a p53-dependent manner. Furthermore, gingerol decreased the expression level of anti-apoptotic proteins (survivin, c-FLIP, Bcl-2, and XIAP) and increased pro-apoptotic protein, Bax and truncate Bid, by generating reactive oxygen species (ROS). We alsomore » found that the sensitizing effects of gingerol in TRAIL-induced cell death were blocked by scavenging ROS or overexpressing anti-apoptotic protein (Bcl-2). Therefore, we showed the functions of gingerol as a sensitizing agent to induce cell death of TRAIL-resistant glioblastoma cells. This study gives rise to the possibility of applying gingerol as an anti-tumor agent that can be used for the purpose of combination treatment with TRAIL in TRAIL-resistant glioblastoma tumor therapy. - Highlights: • Most GBM cells have been reported to be resistant to TRAIL-induced apoptosis. • Gingerol enhances the expression level of anti-apoptotic proteins by ROS. • Gingerol enhances TRAIL-induced apoptosis through actions on the ROS–Bcl2 pathway.« less

PtrA/NINV, an alkaline/neutral invertase gene of Poncirus trifoliata, confers enhanced tolerance to multiple abiotic stresses by modulating ROS levels and maintaining photosynthetic efficiency.

PubMed

Dahro, Bachar; Wang, Fei; Peng, Ting; Liu, Ji-Hong

2016-03-29

Alkaline/neutral invertase (A/N-INV), an enzyme that hydrolyzes sucrose irreversibly into glucose and fructose, is essential for normal plant growth,development, and stress tolerance. However, the physiological and/or molecular mechanism underpinning the role of A/N-INV in abiotic stress tolerance is poorly understood. In this report, an A/N-INV gene (PtrA/NINV) was isolated from Poncirus trifoliata, a cold-hardy relative of citrus, and functionally characterized. PtrA/NINV expression levels were induced by cold, salt, dehydration, sucrose, and ABA, but decreased by glucose. PtrA/NINV was found to localize in both chloroplasts and mitochondria. Overexpression of PtrA/NINV conferred enhanced tolerance to multiple stresses, including cold, high salinity, and drought, as supported by lower levels of reactive oxygen species (ROS), reduced oxidative damages, decreased water loss rate, and increased photosynthesis efficiency, relative to wild-type (WT). The transgenic plants exhibited higher A/N-INV activity and greater reducing sugar content under normal and stress conditions. PtrA/NINV is an important gene implicated in sucrose decomposition, and plays a positive role in abiotic stress tolerance by promoting osmotic adjustment, ROS detoxification and photosynthesis efficiency. Thus, PtrA/NINV has great potential to be used in transgenic breeding for improvement of stress tolerance.

Intracellular redox status controls membrane localization of pro- and anti-migratory signaling molecules.

PubMed

Hempel, Nadine; Melendez, J Andres

2014-01-01

Shifts in intracellular Reactive Oxygen Species (ROS) have been shown to contribute to carcinogenesis and to tumor progression. In addition to DNA and cell damage by surges in ROS, sub-lethal increases in ROS are implicated in regulating cellular signaling that enhances pro-metastatic behavior. We previously showed that subtle increases in endogenous H2O2 regulate migratory and invasive behavior of metastatic bladder cancer cells through phosphatase inhibition and consequential phosphorylation of p130cas, an adapter of the FAK signaling pathway. We further showed that enhanced redox status contributed to enhanced localization of p130cas to the membrane of metastatic cells. Here we show that this signaling complex can similarly be induced in a redox-engineered cell culture model that enables regulation of intracellular steady state H2O2 level by enforced expression of superoxide dismutase 2 (Sod2) and catalase. Expression of Sod2 leads to enhanced p130cas phosphorylation in HT-1080 fibrosarcoma and UM-UC-6 bladder cancer cells. These changes are mediated by H2O2, as co-expression of Catalase abrogates p130cas phosphorylation and its interaction with the adapter protein Crk. Importantly, we establish that the redox environment influence the localization of the tumor suppressor and phosphatase PTEN, in both redox-engineered and metastatic bladder cancer cells that display endogenous increases in H2O2. Importantly, PTEN oxidation leads to its dissociation from the plasma membrane. This indicates that oxidation of PTEN not only influences its activity, but also regulates its cellular localization, effectively removing it from its primary site of lipid phosphatase activity. These data introduce hitherto unappreciated paradigms whereby ROS can reciprocally regulate the cellular localization of pro- and anti-migratory signaling molecules, p130cas and PTEN, respectively. These data further confirm that altering antioxidant status and the intracellular ROS environment can have profound effects on pro-metastatic signaling pathways.

Epidermal fatty acid-binding protein protects nerve growth factor-differentiated PC12 cells from lipotoxic injury

PubMed Central

Liu, Jo-Wen; Montero, Manuel; Bu, Liming; De Leon, Marino

2015-01-01

Epidermal fatty acid-binding protein (E-FABP/FABP5/DA11) binds and transport long-chain fatty acids in the cytoplasm and may play a protecting role during neuronal injury. We examined whether E-FABP protects nerve growth factor-differentiated PC12 cells (NGFDPC12 cells) from lipotoxic injury observed after palmitic acid (C16:0; PAM) overload. NGFDPC12 cells cultures treated with PAM/bovine serum albumin at 0.3 mM/0.15 mM show PAM-induced lipotoxicity (PAM-LTx) and apoptosis. The apoptosis was preceded by a cellular accumulation of reactive oxygen species (ROS) and higher levels of E-FABP. Antioxidants MCI-186 and N-acetyl cysteine prevented E-FABP's induction in expression by PAM-LTx, while tert-butyl hydroperoxide increased ROS and E-FABP expression. Non-metabolized methyl ester of PAM, methyl palmitic acid (mPAM), failed to increase cellular ROS, E-FABP gene expression, or trigger apoptosis. Treatment of NGFDPC12 cultures with siE-FABP showed reduced E-FABP levels correlating with higher accumulation of ROS and cell death after exposure to PAM. In contrast, increasing E-FABP cellular levels by pre-loading the cells with recombinant E-FABP diminished the PAM-induced ROS and cell death. Finally, agonists for PPARβ (GW0742) or PPARγ (GW1929) increased E-FABP expression and enhanced the resistance of NGFDPC12 cells to PAM-LTx. We conclude that E-FABP protects NGFDPC12 cells from lipotoxic injury through mechanisms that involve reduction of ROS. Epidermal fatty acid-binding protein (E-FABP) may protect nerve cells from the damaging exposure to high levels of free fatty acids (FA). We show that E-FABP can neutralize the effects of reactive oxygen species (ROS) generated by the high levels of FA in the cell and protect PC12 cells from lipotoxic injuries common in Type 2 diabetes neuropathy. Potentially, E-FABP gene up-regulation may be mediated through the NFkB pathway and future studies are needed to further evaluate this proposition. PMID:25147052

Hydroxychavicol, a betel leaf component, inhibits prostate cancer through ROS-driven DNA damage and apoptosis

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

Gundala, Sushma Reddy; Yang, Chunhua; Mukkavilli, Rao

Dietary phytochemicals are excellent ROS-modulating agents and have been shown to effectively enhance ROS levels beyond toxic threshold in cancer cells to ensure their selective killing while leaving normal cells unscathed. Here we demonstrate that hydroxychavicol (HC), extracted and purified from Piper betel leaves, significantly inhibits growth and proliferation via ROS generation in human prostate cancer, PC-3 cells. HC perturbed cell-cycle kinetics and progression, reduced clonogenicity and mediated cytotoxicity by ROS-induced DNA damage leading to activation of several pro-apoptotic molecules. In addition, HC treatment elicited a novel autophagic response as evidenced by the appearance of acidic vesicular organelles and increasedmore » expression of autophagic markers, LC3-IIb and beclin-1. Interestingly, quenching of ROS with tiron, an antioxidant, offered significant protection against HC-induced inhibition of cell growth and down regulation of caspase-3, suggesting the crucial role of ROS in mediating cell death. The collapse of mitochondrial transmembrane potential by HC further revealed the link between ROS generation and induction of caspase-mediated apoptosis in PC-3 cells. Our data showed remarkable inhibition of prostate tumor xenografts by ∼ 72% upon daily oral administration of 150 mg/kg bw HC by quantitative tumor volume measurements and non-invasive real-time bioluminescent imaging. HC was well-tolerated at this dosing level without any observable toxicity. This is the first report to demonstrate the anti-prostate cancer efficacy of HC in vitro and in vivo, which is perhaps attributable to its selective prooxidant activity to eliminate cancer cells thus providing compelling grounds for future preclinical studies to validate its potential usefulness for prostate cancer management. - Highlights: • HC perturbs cell-cycle progression by induction of reactive oxygen species (ROS). • HC mediated cytotoxicity by ROS-induced DNA damage leading to apoptosis. • HC induced ROS-mediated autophagic response. • It inhibited prostate tumor growth by ∼ 72% without any observable toxicity. • Its anticancer efficacy is likely due to its selective prooxidant activity.« less

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.

ROS production, intracellular HSP70 levels and their relationship in human neutrophils: effects of age.

PubMed

Kovalenko, Elena I; Boyko, Anna A; Semenkov, Victor F; Lutsenko, Gennady V; Grechikhina, Maria V; Kanevskiy, Leonid M; Azhikina, Tatyana L; Telford, William G; Sapozhnikov, Alexander M

2014-12-15

ROS production and intracellular HSP70 levels were measured in human neutrophils for three age groups: young (20-59 years), elders (60-89 years) and nonagenarians (90 years and older). Elders showed higher levels of spontaneous intracellular ROS content compared with young and nonagenarian groups, which had similar intracellular ROS levels. Zymosan-induced (non-spontaneous) extracellular ROS levels were also similar for young and nonagenarians but were lower in elders. However, spontaneous extracellular ROS production increased continuously with age. Correlation analysis revealed positive relationships between HSP70 levels and zymosan-stimulated ROS production in the elder group. This was consistent with a promoting role for HSP70 in ROS-associated neutrophils response to pathogens. No positive correlation between ROS production and intracellular HSP70 levels was found for groups of young people and nonagenarians. In contrast, significant negative correlations of some ROS and HSP70 characteriscics were found for neutrophils from young people and nonagenarians. The observed difference in ROS and HSP70 correlations in elders and nonagenarians might be associated with an increased risk of mortality in older individuals less than 90 years old.

Curcumin enhances the effects of irinotecan on colorectal cancer cells through the generation of reactive oxygen species and activation of the endoplasmic reticulum stress pathway.

PubMed

Huang, Yan-Feng; Zhu, Da-Jian; Chen, Xiao-Wu; Chen, Qi-Kang; Luo, Zhen-Tao; Liu, Chang-Chun; Wang, Guo-Xin; Zhang, Wei-Jie; Liao, Nv-Zhu

2017-06-20

Although initially effective against metastatic colorectal cancer (CRC), irinotecan-based chemotherapy leads to resistance and adverse toxicity. Curcumin is well known for its anti-cancer effects in many cancers, including CRC. Here, we describe reactive oxygen species (ROS) generation and endoplasmic reticulum (ER) stress as important mechanisms by which curcumin enhances irinotecan's effects on CRC cells. CRC cell lines were treated with curcumin and/or irinotecan for 24 h, and then evaluated using cell proliferation assays, cell apoptosis assays, cell cycle analysis, intracellular Ca2+ measurements, ROS measurements and immunoblotting for key ER stress-related proteins. We found that cell viability was inhibited and apoptosis was increased, accompanied by ROS generation and ER stress activation in CRC cells treated with curcumin alone or in combination with irinotecan. Blocking ROS production attenuated the expression of two markers of ER stress: binding of immunoglobulin protein (BIP) and CCAAT/enhancer-binding protein homologous protein (CHOP). Blocking CHOP expression using RNA interference also inhibited ROS generation. These results demonstrated that curcumin could enhance the effects of irinotecan on CRC cells by inhibiting cell viability and inducing cell cycle arrest and apoptosis, and that these effects may be mediated, in part, by ROS generation and activation of the ER stress pathway.

Reduction of oxidative stress by compression stockings in standing workers.

PubMed

Flore, Roberto; Gerardino, Laura; Santoliquido, Angelo; Catananti, Cesare; Pola, Paolo; Tondi, Paolo

2007-08-01

Healthy workers who stand for prolonged periods show enhanced production of reactive oxygen species (ROS) in their systemic circulation. Oxidative stress is thought to be a risk factor for chronic venous insufficiency and other systemic diseases. To evaluate the effectiveness of compression stockings in the prevention of oxidative stress at work. ROS and venous pressure of the lower limbs were measured in 55 theatre nurses who stood in the operating theatre for >6 h, 23 industrial ironers who stood for up to 5 h during their shift and 65 outpatient department nurses and 35 laundry workers who acted as controls. Subjects and controls were examined on two consecutive days before and after work and with and without compression stockings. Without compression stockings, lower limb venous pressure increased significantly after work in all subjects and controls (P < 0.001), while only operating theatre nurses showed significantly higher mean levels of ROS (P < 0.001). There was no significant difference in venous pressures and ROS levels after work in subjects or controls when wearing compression stockings. Our data suggest a preventive role of compression stockings against oxidative stress in healthy workers with a standing occupation.

Euphorbia milii-native bacteria interactions under airborne formaldehyde stress: Effect of epiphyte and endophyte inoculation in relation to IAA, ethylene and ROS levels.

PubMed

Khaksar, Gholamreza; Treesubsuntorn, Chairat; Thiravetyan, Paitip

2017-02-01

Better understanding of plant-bacteria interactions under stress is of the prime importance for enhancing airborne pollutant phytoremediation. No studies have investigated plant-epiphyte interactions compared to plant-endophyte interactions under airborne formaldehyde stress in terms of plant Indole-3-acetic acid (IAA), ethylene, reactive oxygen species (ROS) levels and pollutant removal efficiency. Euphorbia milii was inoculated with native plant growth-promoting (PGP) endophytic and epiphytic isolates individually to investigate plant-endophyte compared to plant-epiphyte interactions under continuous formaldehyde fumigation. Under airborne formaldehyde stress, endophyte interacts with its host plant closely and provides higher levels of IAA which protected the plant against formaldehyde phytotoxicity by lowering intracellular ROS, ethylene levels and maintaining shoot epiphytic community; hence, higher pollutant removal. However, plant-epiphyte interactions could not provide enough IAA to confer protection against formaldehyde stress; thus, increased ROS and ethylene levels, large decrease in shoot epiphytic population and lower pollutant removal although epiphyte contacts with airborne pollutant directly (has greater access to gaseous formaldehyde). Endophyte-inoculated plant synthesized more tryptophan as a signaling molecule for its associated bacteria to produce IAA compared to the epiphyte-inoculated one. Under stress, PGP endophyte interacts with its host closely; thus, better protection against stress and higher pollutant removal compared to epiphyte which has limited interactions with the host plant; hence, lower pollutant removal. Copyright © 2016 Elsevier Masson SAS. All rights reserved.

Impact of Trans-Resveratrol-Sulfates and -Glucuronides on Endothelial Nitric Oxide Synthase Activity, Nitric Oxide Release and Intracellular Reactive Oxygen Species

PubMed Central

Ladurner, Angela; Schachner, Daniel; Schueller, Katharina; Pignitter, Marc; Heiss, Elke H.; Somoza, Veronika; Dirsch, Verena M.

2015-01-01

Resveratrol (3,5,4′-trihydroxy-trans-stilbene) is a polyphenolic natural product mainly present in grape skin, berries and peanuts. In the vasculature resveratrol is thought to boost endothelial function by increasing endothelial nitric oxide synthase (eNOS) expression, by enhancing eNOS activity, and by reduction of reactive oxygen species (ROS) levels. Recent studies show that dietary resveratrol is metabolized in the liver and intestine into resveratrol-sulfate and -glucuronide derivatives questioning the relevance of multiple reported mechanistic in vitro data on resveratrol. In this study, we compare side by side different physiologically relevant resveratrol metabolites (resveratrol sulfates- and -glucuronides) and their parent compound in their influence on eNOS enzyme activity, endothelial NO release, and intracellular ROS levels. In contrast to resveratrol, none of the tested resveratrol metabolites elevated eNOS enzyme activity and endothelial NO release or affected intracellular ROS levels, leaving the possibility that not tested metabolites are active and able to explain in vivo findings. PMID:25329867

Effect of calcium, bicarbonate, and albumin on capacitation-related events in equine sperm.

PubMed

Macías-García, B; González-Fernández, L; Loux, S C; Rocha, A M; Guimarães, T; Peña, F J; Varner, D D; Hinrichs, K

2015-01-01

Repeatable methods for IVF have not been established in the horse, reflecting the failure of standard capacitating media to induce changes required for fertilization capacity in equine sperm. One important step in capacitation is membrane cholesterol efflux, which in other species is triggered by cholesterol oxidation and is typically enhanced using albumin as a sterol acceptor. We incubated equine sperm in the presence of calcium, BSA, and bicarbonate, alone or in combination. Bicarbonate induced an increase in reactive oxygen species (ROS) that was abolished by the addition of calcium or BSA. Bicarbonate induced protein tyrosine phosphorylation (PY), even in the presence of calcium or BSA. Incubation at high pH enhanced PY but did not increase ROS production. Notably, no combination of these factors was associated with significant cholesterol efflux, as assessed by fluorescent quantitative cholesterol assay and confirmed by filipin staining. By contrast, sperm treated with methyl-β-cyclodextrin showed a significant reduction in cholesterol levels, but no significant increase in PY or ROS. Presence of BSA increased sperm binding to bovine zonae pellucidae in all three stallions. These results show that presence of serum albumin is not associated with a reduction in membrane cholesterol levels in equine sperm, highlighting the failure of equine sperm to exhibit core capacitation-related changes in a standard capacitating medium. These data indicate an atypical relationship among cholesterol efflux, ROS production, and PY in equine sperm. Our findings may help to elucidate factors affecting failure of equine IVF under standard conditions. © 2015 Society for Reproduction and Fertility.

Cigarette smokers develop altered erythrocyte membrane composition: an investigation unmasking the role of membrane bound integral protein GLUT 1.

PubMed

Sikdar, Jyotirmoy; Seal, Paromita; Roy, Amartya; Haldar, Rajen

2017-04-01

Erythrocytes in cigarette smokers are prone to oxidative damage. Here, we sought to elucidate the facts behind modifications and possible defense system developed in erythrocyte of cigarette smokers. We observed significant increase in stomatocytes and spherocytes, and osmotic fragility of erythrocyte, along with reduced level of protein thiol and increased fluorescence anisotropy in isolated membrane. Denaturing gel electrophoresis indicated alterations in band 3, band 4.2 and band 4.5. Among those, Glut 1 (i.e. band 4.5), which transports glucose (insulin independent) and dehydroascorbate (DHA), was selectively chosen for its long history in reducing reactive oxygen species (ROS). The increased Glut 1 level in smokers was confirmed by immunoblotting and immunocytochemistry. Furthermore, smokers showed significantly higher glucose uptake in whole blood. The intracellular (Ic) ROS (as indicated by 2',7'-dichlorofluorescin) was significantly higher in smokers as evidenced by flow cytometric assay. Glucose and DHA alone or together significantly reduced IcROS at higher rate in smokers. However, in presence of Glut 1 specific blocker, phloretin, neither glucose nor DHA could reduce IcROS in both non-smokers and smokers. This confirms that Glut 1 by transporting glucose or DHA attenuates IcROS. Therefore, we conclude that erythrocytes, although altered morphologically, also develop a defense system by upregulating Glut 1 to combat with enhanced Ic oxidative insult in cigarette smokers.

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

PubMed Central

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

2017-01-01

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

Chemical exposure-response relationship between air pollutants and reactive oxygen species in the human respiratory tract

NASA Astrophysics Data System (ADS)

Lakey, Pascale S. J.; Berkemeier, Thomas; Tong, Haijie; Arangio, Andrea M.; Lucas, Kurt; Pöschl, Ulrich; Shiraiwa, Manabu

2016-09-01

Air pollution can cause oxidative stress and adverse health effects such as asthma and other respiratory diseases, but the underlying chemical processes are not well characterized. Here we present chemical exposure-response relations between ambient concentrations of air pollutants and the production rates and concentrations of reactive oxygen species (ROS) in the epithelial lining fluid (ELF) of the human respiratory tract. In highly polluted environments, fine particulate matter (PM2.5) containing redox-active transition metals, quinones, and secondary organic aerosols can increase ROS concentrations in the ELF to levels characteristic for respiratory diseases. Ambient ozone readily saturates the ELF and can enhance oxidative stress by depleting antioxidants and surfactants. Chemical exposure-response relations provide a quantitative basis for assessing the relative importance of specific air pollutants in different regions of the world, showing that aerosol-induced epithelial ROS levels in polluted megacity air can be several orders of magnitude higher than in pristine rainforest air.

Trichostatin A inhibits radiation-induced epithelial-to-mesenchymal transition in the alveolar epithelial cells

PubMed Central

Nagarajan, Devipriya; Wang, Lei; Zhao, Weiling; Han, Xiaochen

2017-01-01

Radiation-induced pneumonitis and fibrosis are major complications following thoracic radiotherapy. Epithelial-to-mesenchymal transition (EMT) plays an important role in tissue injury leading to organ fibrosis, including lung. Our previous studies have reported that radiation can induce EMT in the type II alveolar epithelial cells in both in vitro and in vivo. HDAC inhibitors are a new family of anti-cancer agents currently being used in several clinical trials. In addition to their intrinsic anti-tumor properties, HDAC inhibition is also important in other human diseases, including fibrosis and radiation-induced damage. In this study, we evaluated the effect of Trichostatin A (TSA), a HDAC inhibitor, on radiation-induced EMT in type II alveolar epithelial cells (RLE-6TN). Pre-treatment of RLE-6TN cells with TSA inhibited radiation-induced EMT-like morphological alterations including elevated protein level of α-SMA and Snail, reduction of E-cadherin expression, enhanced phosphorylation of GSK3β and ERK1/2, increased generation of ROS. Radiation enhanced the protein level of TGF-β1, which was blocked by N-acetylcysteine, an antioxidant. Treating cells with SB-431542, TGF-β1 type I receptor inhibitor, diminished radiation-induced alterations in the protein levels of p-GSK-3β, Snail-1 and α-SMA, suggesting a regulatory role of TGF-β1 in EMT. Pre-incubation of cells with TSA showed significant decrease in the level of TGF-β1 compared to radiation control. Collectively, these results demonstrate that i] radiation-induced EMT in RLE-6TN cells is mediated by ROS/MEK/ERK and ROS/TGF-β1 signaling pathways and ii] the inhibitory role of TSA in radiation-induced EMT appears to be due, at least in part, to its action of blocking ROS and TGF-β1 signaling. PMID:29254201

Lack of a Cytoplasmic RLK, Required for ROS Homeostasis, Induces Strong Resistance to Bacterial Leaf Blight in Rice.

PubMed

Yoo, Youngchul; Park, Jong-Chan; Cho, Man-Ho; Yang, Jungil; Kim, Chi-Yeol; Jung, Ki-Hong; Jeon, Jong-Seong; An, Gynheung; Lee, Sang-Won

2018-01-01

Many scientific findings have been reported on the beneficial function of reactive oxygen species (ROS) in various cellular processes, showing that they are not just toxic byproducts. The double-edged role of ROS shows the importance of the regulation of ROS level. We report a gene, rrsRLK (required for ROS-scavenging receptor-like kinase), that encodes a cytoplasmic RLK belonging to the non-RD kinase family. The gene was identified by screening rice RLK mutant lines infected with Xanthomonas oryzae pv. oryzae ( Xoo ), an agent of bacterial leaf blight of rice. The mutant (Δ rrsRLK ) lacking the Os01g02290 gene was strongly resistant to many Xoo strains, but not to the fungal pathogen Magnaporthe grisea . Δ rrsRLK showed significantly higher expression of OsPR1a , OsPR1b , OsLOX , RBBTI4 , and jasmonic acid-related genes than wild type. We showed that rrsRLK protein interacts with OsVOZ1 (vascular one zinc-finger 1) and OsPEX11 (peroxisomal biogenesis factor 11). In the further experiments, abnormal biogenesis of peroxisomes, hydrogen peroxide (H 2 O 2 ) accumulation, and reduction of activity of ROS-scavenging enzymes were investigated in Δ rrsRLK . These results suggest that the enhanced resistance in Δ rrsRLK is due to H 2 O 2 accumulation caused by irregular ROS-scavenging mechanism, and rrsRLK is most likely a key regulator required for ROS homeostasis in rice.

Ganoderma atrum polysaccharide ameliorates ROS generation and apoptosis in spleen and thymus of immunosuppressed mice.

PubMed

Li, Wen-Juan; Li, Lu; Zhen, Weng-Ya; Wang, Le-Feng; Pan, Meng; Lv, Jia-Qian; Wang, Fan; Yao, Yu-Fei; Nie, Shao-Ping; Xie, Ming-Yong

2017-01-01

Ganoderma atrum polysaccharide (PSG-1) is a bioactive compound with antioxidant and immunomodulatory activities. The aim of this study was to determine the effect of PSG-1 on reactive oxygen species (ROS) generation and apoptosis in spleen and thymus of cyclophosphamide (CTX)-induced immunosuppressed mice. The results showed that PSG-1 protected mice against CTX-mediated immunosuppression, as evidenced by enhancing the ratios of thymus and spleen weights to body weight, promoting T cell and B cell survival, and increasing levels of TNF-α and IL-2. Apoptosis, ROS generation and lipid peroxidation in the immune organs of the immunosuppressed animals were ameliorated by PSG-1. The immune benefits of PSG-1 were associated with the enhancement of the activities of glutathione peroxidase, superoxide dismutase and catalase in the immune organs, implying that antioxidant activities of PSG-1 may play an important role in PSG-1-evoked immune protection. Taken together, these findings have demonstrated that PSG-1 may ameliorate CTX-induced immunosuppression through reducing apoptosis and oxidative damage in immunological system. Copyright © 2016. Published by Elsevier Ltd.

The evolution of a mechanism of cell suicide.

PubMed

Blackstone, N W; Green, D R

1999-01-01

In the vertebrates, programmed cell death or apoptosis frequently involves the relocalization of mitochondrial cytochrome c to the cytoplasm. This prominent role in the regulation of apoptosis is in addition to the primary function of cytochrome c in the mitochondrial electron transport chain. These seemingly divergent roles become plausible when considering the symbiotic origin of the mitochondrion. Symbiosis involves conflicts between levels of selection, in this case between the primitive host cell and the protomitochondria. In an aerobic environment, selection on the protomitochondria may have favored routine manipulations of the host cell's phenotype using products and by-products of oxidative phosphorylation, in particular reactive oxygen species (ROS). Blocking the mitochondrial electron transport chain by removing cytochrome c enhances the production of ROS; thus cytochrome c release by protomitochondria may have altered the host cell's phenotype via enhanced ROS production. Subsequently, this signaling pathway may have been refined by selection so that cytochrome c itself became the trigger for changes in the host's phenotype. A mechanism of apoptosis in metazoans may thus be a vestige of evolutionary conflicts within the eukaryotic cell.

Seawater inhalation induces acute lung injury via ROS generation and the endoplasmic reticulum stress pathway

PubMed Central

Li, Cong-Cong; Lu, Xi; Qian, Wei-Sheng; Li, Yu-Juan; Jin, Fa-Guang; Mu, De-Guang

2018-01-01

Seawater (SW) inhalation can induce acute lung injury (ALI) and acute respiratory distress syndrome (ARDS). In the present study, SW induced apoptosis of rat alveolar epithelial cells and histopathological alterations to lung tissue. Furthermore, SW administration increased generation of reactive oxygen species (ROS), whereas pretreatment with the ROS scavenger, N-acetyl-L-cysteine (NAC), significantly decreased ROS generation, apoptosis and histopathological alterations. In addition, SW exposure upregulated the expression levels of glucose-regulated protein 78 (GRP78) and CCAAT/enhancer binding protein homologous protein (CHOP), which are critical proteins in the endoplasmic reticulum (ER) stress response, thus indicating that SW may activate ER stress. Conversely, blocking ER stress with 4-phenylbutyric acid (4-PBA) significantly improved SW-induced apoptosis and histopathological alterations, whereas an ER stress inducer, thapsigargin, had the opposite effect. Furthermore, blocking ROS with NAC inhibited SW-induced ER stress, as evidenced by the downregulation of GRP78, phosphorylated (p)-protein kinase R-like ER kinase (PERK), p-inositol-requiring kinase 1α (IRE1α), p-50 activating transcription factor 6α and CHOP. In addition, blocking ER stress with 4-PBA decreased ROS generation. In conclusion, the present study indicated that ROS and ER stress pathways, which are involved in alveolar epithelial cell apoptosis, are important in the pathogenesis of SW-induced ALI. PMID:29436612

The Glutaminase-1 Inhibitor 968 Enhances Dihydroartemisinin-Mediated Antitumor Efficacy in Hepatocellular Carcinoma Cells

PubMed Central

Zheng, Meihong; Zhang, Yonghui; Chen, Aiping; Wu, Junhua; Wei, Jiwu

2016-01-01

Reprogrammed metabolism and redox homeostasis are potential targets of cancer therapy. Our previous study demonstrated that the kidney form of glutaminase (GLS1) is highly expressed in hepatocellular carcinoma (HCC) cells and can be used as a target for effective anticancer therapy. Dihydroartemisinin (DHA) increases intracellular reactive oxygen species (ROS) levels leading to cytotoxicity in cancer cells. However, the heterogeneity of cancer cells often leads to differing responses to oxidative lesions. For instance, cancer cells with high ratio of GSH/GSSG, a critical ROS scavenger, are resistant to ROS-induced cytotoxicity. We postulate that a combinatorial strategy firstly disrupting redox homeostasis followed by DHA might yield a profound antitumor efficacy. In this study, when HCC cells were treated with a GLS1 inhibitor 968, the ROS elimination capacity was significantly reduced in HCC cells, which rendered HCC cells but not normal endothelial cells more sensitive to DHA-mediated cytotoxicity. We further confirmed that this synergistic antitumor efficacy was mediated by excessive ROS generation in HCC cells. NAC, a ROS inhibitor, partly rescued the combinatorial cytotoxic effect of 968 and DHA. Given that GLS1 is a potential antitumor target and DHA has been safely used in clinic, our findings provide new insight into liver cancer therapy targeting glutamine metabolism combined with the ROS generator DHA, which can be readily translated into cancer clinical trials. PMID:27835669

Radio-sensitization by Piper longumine of human breast adenoma MDA-MB-231 cells in vitro.

PubMed

Yao, Jian-Xin; Yao, Zhi-Feng; Li, Zhan-Feng; Liu, Yong-Biao

2014-01-01

The current study investigated the effects of Piper longumine on radio-sensitization of human breast cancer MDA-MB-231 cells and underlying mechanisms. Human breast cancer MDA-MB-231 cells were cultured in vitro and those in logarithmic growth phase were selected for experiments divided into four groups: control, X-ray exposed, Piper longumine, and Piper longumine combined with X-rays. Conogenic assays were performed to determine the radio-sensitizing effects. Cell survival curves were fitted by single-hit multi-target model and then the survival fraction (SF), average lethal dose (D0), quasi-threshold dose (Dq) and sensitive enhancement ratio (SER) were calculated. Cell apoptosis was analyzed by flow cytometry (FCM).Western blot assays were employed for expression of apoptosis-related proteins (Bc1-2 and Bax) after treatment with Piper longumine and/or X-ray radiation. The intracellular reactive oxygen species (ROS) level was detected by FCM with a DCFH-DA probe. The cloning formation capacity was decreased in the group of piperlongumine plus radiation, which displayed the values of SF2, D0, Dq significantly lower than those of radiation alone group and the sensitive enhancement ratio (SER) of D0 was1.22 and 1.29, respectively. The cell apoptosis rate was increased by the combination treatment of Piper longumine and radiation. Piper longumine increased the radiation-induced intracellular levels of ROS. Compared with the control group and individual group, the combination group demonstrated significantly decreased expression of Bcl-2 with increased Bax. Piper longumine at a non-cytotoxic concentration can enhance the radio-sensitivity of MDA- MB-231cells, which may be related to its regulation of apoptosis-related protein expression and the increase of intracellular ROS level, thus increasing radiation-induced apoptosis.

Cadmium toxicity in Maize (Zea mays L.): consequences on antioxidative systems, reactive oxygen species and cadmium accumulation.

PubMed

Anjum, Shakeel Ahmad; Tanveer, Mohsin; Hussain, Saddam; Bao, Mingchen; Wang, Longchang; Khan, Imran; Ullah, Ehsan; Tung, Shahbaz Atta; Samad, Rana Abdul; Shahzad, Babar

2015-11-01

Increased cadmium (Cd) accumulation in soils has led to tremendous environmental problems, with pronounced effects on agricultural productivity. Present study investigated the effects of Cd stress imposed at various concentrations (0, 75, 150, 225, 300, 375 μM) on antioxidant activities, reactive oxygen species (ROS), Cd accumulation, and productivity of two maize (Zea mays L.) cultivars viz., Run Nong 35 and Wan Dan 13. Considerable variations in Cd accumulation and in behavior of antioxidants and ROS were observed under Cd stress in both maize cultivars, and such variations governed by Cd were concentration dependent. Exposure of plant to Cd stress considerably increased Cd concentration in all plant parts particularly in roots. Wan Dan 13 accumulated relatively higher Cd in root, stem, and leaves than Run Nong 35; however, in seeds, Run Nong 35 recorded higher Cd accumulation. All the Cd toxicity levels starting from 75 μM enhanced H2O2 and MDA concentrations and triggered electrolyte leakage in leaves of both cultivars, and such an increment was more in Run Nong 35. The ROS were scavenged by the enhanced activities of superoxide dismutase, peroxidase, catalase, ascorbate peroxidase, and glutathione peroxidase in response to Cd stress, and these antioxidant activities were higher in Wan Dan 13 compared with Run Nong 35 at all Cd toxicity levels. The grain yield of maize was considerably reduced particularly for Run Nong 35 under different Cd toxicity levels as compared with control. The Wan Dan 13 was better able to alleviate Cd-induced oxidative damage which was attributed to more Cd accumulation in roots and higher antioxidant activities in this cultivar, suggesting that manipulation of these antioxidants and enhancing Cd accumulation in roots may lead to improvement in Cd stress tolerance.

The orally active pterocarpanquinone LQB-118 exhibits cytotoxicity in prostate cancer cell and tumor models through cellular redox stress.

PubMed

Martino, Thiago; Kudrolli, Tarana A; Kumar, Binod; Salviano, Isis; Mencalha, André; Coelho, Marsen Garcia P; Justo, Graça; Costa, Paulo R Ribeiro; Sabino, Kátia C Carvalho; Lupold, Shawn E

2018-02-01

The targeted induction of reactive oxygen species (ROS) is a developing mechanism for cancer therapy. LQB-118 is a pterocarpanquinone and ROS-inducing agent with proven antineoplastic activity. Here, LQB-118 efficacy and mechanism of activity, were examined in Prostate Cancer (PCa) cell and tumor models. PC3, LNCaP, and LAPC4 PCa cells were applied. Dicoumarol treatment was used to inhibit quinone reductase activity. N-acetylcysteine (NAC) was applied as a ROS scavenger. ROS production was quantified by H 2 DCFDA flow cytometry. LQB-118 treated cells were evaluated for changes in lipid peroxidation, viability, and apoptosis. Treatment-induced gene expression was measured by RT-qPCR and Western Blot. SOD1 knockdown was achieved with siRNA or miRNA mimic transfection. MicroRNA specificity was determined by 3'UTR reporter assay. Oral LQB-118 treatment (10 mg/kg/day) efficacy was determined in athymic male nude mice bearing subcutaneous PC3 xenograft tumors. LQB-118 treatment triggered PCa cell death and apoptosis. Therapeutic activity was at least partially dependent upon quinone reduction and ROS generation. LQB-118 treatment caused an increase in cellular ROS and lipid peroxidation. Treated cells exhibited elevated levels of NQO1, Nrf2, and SOD1. The miRNAs miR-206, miR-1, and miR-101 targeted and reduced SOD1 expression. The knockdown of SOD1, by siRNA or miRNA, enhanced LQB-118 cytotoxicity. Orally administered LQB-118 treatment significantly reduced the growth of established PCa xenograft tumors. LQB-118 is a developing and orally active pterocarpanquinone agent that effectively kills PCa cells through quinone reduction and ROS generation. The inhibition SOD1 expression enhances LQB-118 activity, presumably by impairing the cellular antioxidant response. © 2017 Wiley Periodicals, Inc.

Salmonella utilizes zinc to subvert anti-microbial host defense of macrophages via modulation of NF-κB signaling.

PubMed

Wu, Aimin; Tymoszuk, Piotr; Haschka, David; Heeke, Simon; Dichtl, Stefanie; Petzer, Verena; Seifert, Markus; Hilbe, Richard; Sopper, Sieghart; Talasz, Heribert; Bumann, Dirk; Lass-Flörl, Cornelia; Theurl, Igor; Zhang, Keying; Weiss, Guenter

2017-09-05

Zinc sequestration by macrophages is considered a crucial host defense strategy against infection with the intracellular bacterium Salmonella Typhimurium. However, the underlying mechanisms remain elusive. In this study we found zinc to favor pathogen survival within macrophages. Salmonella -hosting macrophages contained higher free zinc levels than uninfected macrophages and cells that successfully eliminated bacteria, which was paralleled by impaired production of reactive oxygen (ROS) and nitrogen (RNS) species in bacteria-harboring cells. A profound, zinc-mediated inhibition of NF-κB p65 transcriptional activity affecting expression of the ROS- and RNS-forming enzymes phos47 and iNOS provided a mechanistic explanation for this phenomenon. Macrophages responded to infection by enhanced expression of zinc scavenging methallothioneins-1 and 2, whose genetic deletion caused a rise of free zinc levels, reduced ROS and RNS production and increased survival of Salmonella Our data suggest that Salmonella invasion of macrophages results in a bacteria-driven rise of intracellular zinc levels which weakens anti-microbial defense and the ability of macrophages to eradicate the pathogen. Thus, limitation of cytoplasmic zinc levels may help to control infection with intracellular bacteria. Copyright © 2017 Wu et al.

Quercetin attenuates mitochondrial dysfunction and biogenesis via upregulated AMPK/SIRT1 signaling pathway in OA rats.

PubMed

Qiu, Linan; Luo, Yuju; Chen, Xiaojuan

2018-07-01

Despite the severity of osteoarthritis (OA), current medical therapy strategies for OA aim at symptom control and pain reduction, as there is no ideal drug for effective OA treatment. OA rat model was used to explore the therapeutic function of quercetin on remission of OA, by determining the reactive oxygen species (ROS) levels, mitochondrial function and extracellular matrix integrity. Quercetin could attenuate ROS generation and augment the glutathione (GSH) and glutathione peroxidase (GPx) expression levels in OA rat. Quercetin not only enhanced mitochondrial membrane potential, oxygen consumption, adenosine triphosphate (ATP) levels in mitochondria, but also increased the mitochondrial copy number. Furthermore, the interlukin (IL)-1β-induced accumulation of nitric oxide (NO), matrixmetalloproteinase (MMP)-3) and MMP-13 could be suppressed by quercetin. Finally, we confirmed that the therapeutic properties of quercetin on OA might function through the adenosine monophosphate-activated protein kinase/sirtuin 1 (AMPK/SIRT1) signaling pathway. In summary, quercetin could alleviate OA through attenuating the ROS levels, reversing the mitochondrial dysfunction and keeping the integrality of extracellular matrix of joint cartilage. The underlying mechanism might involve the regulation of AMPK/SIRT1 signaling pathway. Copyright © 2018 Elsevier Masson SAS. All rights reserved.

Role of reactive oxygen species in arsenic-induced transformation of human lung bronchial epithelial (BEAS-2B) cells

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

Zhang, Zhuo, E-mail: zhuo.zhang@uky.edu; Pratheeshkumar, Poyil; Budhraja, Amit

Highlights: • Short term exposure of cells to arsenic causes ROS generation. • Chronical exposure of cells to arsenic causes malignant cell transformation. • Inhibition of ROS generation reduces cell transformation by arsenic. • Arsenic-transformed cells exhibit reduced capacity of generating ROS. • Arsenic-transformed cells exhibit increased levels of antioxidants. - Abstract: Arsenic is an environmental carcinogen, its mechanisms of carcinogenesis remain to be investigated. Reactive oxygen species (ROS) are considered to be important. A previous study (Carpenter et al., 2011) has measured ROS level in human lung bronchial epithelial (BEAS-2B) cells and arsenic-transformed BEAS-2B cells and found that ROSmore » levels were higher in transformed cells than that in parent normal cells. Based on these observations, the authors concluded that cell transformation induced by arsenic is mediated by increased cellular levels of ROS. This conclusion is problematic because this study only measured the basal ROS levels in transformed and parent cells and did not investigate the role of ROS in the process of arsenic-induced cell transformation. The levels of ROS in arsenic-transformed cells represent the result and not the cause of cell transformation. Thus question concerning whether ROS are important in arsenic-induced cell transformation remains to be answered. In the present study, we used expressions of catalase (antioxidant against H{sub 2}O{sub 2}) and superoxide dismutase 2 (SOD2, antioxidant against O{sub 2}{sup ·−}) to decrease ROS level and investigated their role in the process of arsenic-induced cell transformation. Our results show that inhibition of ROS by antioxidant enzymes decreased arsenic-induced cell transformation, demonstrating that ROS are important in this process. We have also shown that in arsenic-transformed cells, ROS generation was lower and levels of antioxidants are higher than those in parent cells, in a disagreement with the previous report. The present study has also shown that the arsenic-transformed cells acquired apoptosis resistance. The inhibition of catalase to increase ROS level restored apoptosis capability of arsenic-transformed BEAS-2B cells, further showing that ROS levels are low in these cells. The apoptosis resistance due to the low ROS levels may increase cells proliferation, providing a favorable environment for tumorigenesis of arsenic-transformed cells.« less

Literature-based discovery of diabetes- and ROS-related targets

PubMed Central

2010-01-01

Background Reactive oxygen species (ROS) are known mediators of cellular damage in multiple diseases including diabetic complications. Despite its importance, no comprehensive database is currently available for the genes associated with ROS. Methods We present ROS- and diabetes-related targets (genes/proteins) collected from the biomedical literature through a text mining technology. A web-based literature mining tool, SciMiner, was applied to 1,154 biomedical papers indexed with diabetes and ROS by PubMed to identify relevant targets. Over-represented targets in the ROS-diabetes literature were obtained through comparisons against randomly selected literature. The expression levels of nine genes, selected from the top ranked ROS-diabetes set, were measured in the dorsal root ganglia (DRG) of diabetic and non-diabetic DBA/2J mice in order to evaluate the biological relevance of literature-derived targets in the pathogenesis of diabetic neuropathy. Results SciMiner identified 1,026 ROS- and diabetes-related targets from the 1,154 biomedical papers (http://jdrf.neurology.med.umich.edu/ROSDiabetes/). Fifty-three targets were significantly over-represented in the ROS-diabetes literature compared to randomly selected literature. These over-represented targets included well-known members of the oxidative stress response including catalase, the NADPH oxidase family, and the superoxide dismutase family of proteins. Eight of the nine selected genes exhibited significant differential expression between diabetic and non-diabetic mice. For six genes, the direction of expression change in diabetes paralleled enhanced oxidative stress in the DRG. Conclusions Literature mining compiled ROS-diabetes related targets from the biomedical literature and led us to evaluate the biological relevance of selected targets in the pathogenesis of diabetic neuropathy. PMID:20979611

Sulfasalazine attenuates evading anticancer response of CD133-positive hepatocellular carcinoma cells.

PubMed

Song, Yeonhwa; Jang, Jaewoo; Shin, Tae-Hoon; Bae, Sang Mun; Kim, Jin-Sun; Kim, Kang Mo; Myung, Seung-Jae; Choi, Eun Kyung; Seo, Haeng Ran

2017-03-03

CD133-positive cells in hepatocellular carcinoma (HCC) exhibit cancer stem cell (CSC)-like properties as well as resistance to chemotherapeutic agents and ionizing radiation; however, their function remains unknown. In this paper, we identified a hitherto unknown mechanism to overcome CD133-induced resistance to anticancer therapy. We applied an alternative approach to enrich the CD133-positive HCC population by manipulating 3D culture conditions. Defense mechanisms against reactive oxygen species (ROS) in CSC spheroids were evaluated by fluorescence image-based phenotypic screening system. Further, we studied the effect of sulfasalazine on ROS defense system and synergistic therapeutic efficacy of anticancer therapies both in culture and in vivo HCC xenograft mouse model. Here, we found that oxidative stress increase CD133 expression in HCC and increased CD133 expression enhanced the capacity of the defense system against ROS, and thereby play a central role in resistance to liver cancer therapy. Moreover, ablation of CD133 attenuated not only the capacity for defense against ROS, but also chemoresistance, in HCC through decreasing glutathione (GSH) levels in vitro. Sulfasalazine, a potent xCT inhibitor that plays an important role in maintaining GSH levels, impaired the ROS defense system and increased the therapeutic efficacy of anticancer therapies in CD133-positive HCC but not CD133-negative HCC in vivo and in vitro. These results strongly indicate functional roles for CD133 in ROS defense and in evading anticancer therapies in HCC, and suggest that sulfasalazine, administered in combination with conventional chemotherapy, might be an effective strategy against CD133-positive HCC cells.

Activation of PPARδ counteracts angiotensin II-induced ROS generation by inhibiting rac1 translocation in vascular smooth muscle cells.

PubMed

Lee, Hanna; Ham, Sun Ah; Kim, Min Young; Kim, Jae-Hwan; Paek, Kyung Shin; Kang, Eun Sil; Kim, Hyo Jung; Hwang, Jung Seok; Yoo, Taesik; Park, Chankyu; Kim, Jin-Hoi; Lim, Dae-Seog; Han, Chang Woo; Seo, Han Geuk

2012-07-01

Angiotensin II (Ang II)-mediated modification of the redox milieu of vascular smooth muscle cells (VSMCs) has been implicated in several pathophysiological processes, including cell proliferation, migration and differentiation. In this study, we demonstrate that the peroxisome proliferator-activated receptor (PPAR) δ counteracts Ang II-induced production of reactive oxygen species (ROS) in VSMCs. Activation of PPARδ by GW501516, a specific ligand for PPARδ, significantly reduced Ang II-induced ROS generation in VSMCs. This effect was, however, reversed in the presence of small interfering (si)RNA against PPARδ. The marked increase in ROS levels induced by Ang II was also eliminated by the inhibition of phosphatidylinositol 3-kinase (PI3K) but not of protein kinase C, suggesting the involvement of the PI3K/Akt signalling pathway in this process. Accordingly, ablation of Akt with siRNA further enhanced the inhibitory effects of GW501516 in Ang II-induced superoxide production. Ligand-activated PPARδ also blocked Ang II-induced translocation of Rac1 to the cell membrane, inhibiting the activation of NADPH oxidases and consequently ROS generation. These results indicate that ligand-activated PPARδ plays an important role in the cellular response to oxidative stress by decreasing ROS generated by Ang II in vascular cells.

Alteration of respiration capacity and transcript accumulation level of alternative oxidase genes in necrosis lines of common wheat.

PubMed

Sugie, Atsushi; Murai, Koji; Takumi, Shigeo

2007-06-01

Mitochondrial alternative oxidase (AOX) is the terminal oxidase responsible for cyanide-insensitive and salicylhydroxamic acid-sensitive respiration in plants. AOX is a key enzyme of the alternative respiration pathway. To study the effects of necrotic cell death on the mitochondrial function, production of reactive oxygen species (ROS), respiration capacities and accumulation patterns of mitochondria-targeted protein-encoding gene transcripts were compared between wild-type, lesion-mimic mutant and hybrid necrosis wheat plants. Around cells with the necrosis symptom, ROS accumulated abundantly in the intercellular spaces. The ratio of the alternative pathway to the cytochrome pathway was markedly enhanced in the necrotic leaves. Transcripts of a wheat AOX gene, Waox1a, were more abundant in a novel lesion-mimic mutant of common wheat than in the wild-type plants. An increased level of the Waox1a transcripts was also observed in hybrid plants containing Ne1 and Ne2 genes. These results indicated that an increase of the wheat AOX transcript level resulted in enhancement of respiration capacity of the alternative pathway in the necrotic cells.

Mitochondrial dysfunction enhances cisplatin resistance in human gastric cancer cells via the ROS-activated GCN2-eIF2α-ATF4-xCT pathway

PubMed Central

Wang, Sheng-Fan; Chen, Meng-Shian; Chou, Yueh-Ching; Ueng, Yune-Fang; Yin, Pen-Hui; Yeh, Tien-Shun; Lee, Hsin-Chen

2016-01-01

Mitochondrial DNA mutations and defects in mitochondrial enzymes have been identified in gastric cancers, and they might contribute to cancer progression. In previous studies, mitochondrial dysfunction was induced by oligomycin-enhanced chemoresistance to cisplatin. Herein, we dissected the regulatory mechanism for mitochondrial dysfunction-enhanced cisplatin resistance in human gastric cancer cells. Repeated cisplatin treatment-induced cisplatin-resistant cells exhibited high SLC7A11 (xCT) expression, and xCT inhibitors (sulfasalazine or erastin), xCT siRNA, or a GSH synthesis inhibitor (buthionine sulphoximine, BSO) could sensitize these cells to cisplatin. Clinically, the high expression of xCT was associated with a poorer prognosis for gastric cancer patients under adjuvant chemotherapy. Moreover, we found that mitochondrial dysfunction enhanced cisplatin resistance and up-regulated xCT expression, as well as intracellular glutathione (GSH). The xCT inhibitors, siRNA against xCT or BSO decreased mitochondrial dysfunction-enhanced cisplatin resistance. We further demonstrated that the upregulation of the eIF2α-ATF4 pathway contributed to mitochondrial dysfunction-induced xCT expression, and activated eIF2α kinase GCN2, but not PERK, stimulated the eIF2α-ATF4-xCT pathway in response to mitochondrial dysfunction-increased reactive oxygen species (ROS) levels. In conclusion, our results suggested that the ROS-activated GCN2-eIF2α-ATF4-xCT pathway might contribute to mitochondrial dysfunction-enhanced cisplatin resistance and could be a potential target for gastric cancer therapy. PMID:27708226

Mitochondrial dysfunction enhances cisplatin resistance in human gastric cancer cells via the ROS-activated GCN2-eIF2α-ATF4-xCT pathway.

PubMed

Wang, Sheng-Fan; Chen, Meng-Shian; Chou, Yueh-Ching; Ueng, Yune-Fang; Yin, Pen-Hui; Yeh, Tien-Shun; Lee, Hsin-Chen

2016-11-08

Mitochondrial DNA mutations and defects in mitochondrial enzymes have been identified in gastric cancers, and they might contribute to cancer progression. In previous studies, mitochondrial dysfunction was induced by oligomycin-enhanced chemoresistance to cisplatin. Herein, we dissected the regulatory mechanism for mitochondrial dysfunction-enhanced cisplatin resistance in human gastric cancer cells. Repeated cisplatin treatment-induced cisplatin-resistant cells exhibited high SLC7A11 (xCT) expression, and xCT inhibitors (sulfasalazine or erastin), xCT siRNA, or a GSH synthesis inhibitor (buthionine sulphoximine, BSO) could sensitize these cells to cisplatin. Clinically, the high expression of xCT was associated with a poorer prognosis for gastric cancer patients under adjuvant chemotherapy. Moreover, we found that mitochondrial dysfunction enhanced cisplatin resistance and up-regulated xCT expression, as well as intracellular glutathione (GSH). The xCT inhibitors, siRNA against xCT or BSO decreased mitochondrial dysfunction-enhanced cisplatin resistance. We further demonstrated that the upregulation of the eIF2α-ATF4 pathway contributed to mitochondrial dysfunction-induced xCT expression, and activated eIF2α kinase GCN2, but not PERK, stimulated the eIF2α-ATF4-xCT pathway in response to mitochondrial dysfunction-increased reactive oxygen species (ROS) levels. In conclusion, our results suggested that the ROS-activated GCN2-eIF2α-ATF4-xCT pathway might contribute to mitochondrial dysfunction-enhanced cisplatin resistance and could be a potential target for gastric cancer therapy.

Hyperglycemic Conditions Prime Cells for RIP1-dependent Necroptosis*

PubMed Central

LaRocca, Timothy J.; Sosunov, Sergey A.; Shakerley, Nicole L.; Ten, Vadim S.; Ratner, Adam J.

2016-01-01

Necroptosis is a RIP1-dependent programmed cell death (PCD) pathway that is distinct from apoptosis. Downstream effector pathways of necroptosis include formation of advanced glycation end products (AGEs) and reactive oxygen species (ROS), both of which depend on glycolysis. This suggests that increased cellular glucose may prime necroptosis. Here we show that exposure to hyperglycemic levels of glucose enhances necroptosis in primary red blood cells (RBCs), Jurkat T cells, and U937 monocytes. Pharmacologic or siRNA inhibition of RIP1 prevented the enhanced death, confirming it as RIP1-dependent necroptosis. Hyperglycemic enhancement of necroptosis depends upon glycolysis with AGEs and ROS playing a role. Total levels of RIP1, RIP3, and mixed lineage kinase domain-like (MLKL) proteins were increased following treatment with high levels of glucose in Jurkat and U937 cells and was not due to transcriptional regulation. The observed increase in RIP1, RIP3, and MLKL protein levels suggests a potential positive feedback mechanism in nucleated cell types. Enhanced PCD due to hyperglycemia was specific to necroptosis as extrinsic apoptosis was inhibited by exposure to high levels of glucose. Hyperglycemia resulted in increased infarct size in a mouse model of brain hypoxia-ischemia injury. The increased infarct size was prevented by treatment with nec-1s, strongly suggesting that increased necroptosis accounts for exacerbation of this injury in conditions of hyperglycemia. This work reveals that hyperglycemia represents a condition in which cells are extraordinarily susceptible to necroptosis, that local glucose levels alter the balance of PCD pathways, and that clinically relevant outcomes may depend on glucose-mediated effects on PCD. PMID:27129772

Pioglitazone restores phagocyte mitochondrial oxidants and bactericidal capacity in chronic granulomatous disease.

PubMed

Fernandez-Boyanapalli, Ruby F; Frasch, S Courtney; Thomas, Stacey M; Malcolm, Kenneth C; Nicks, Michael; Harbeck, Ronald J; Jakubzick, Claudia V; Nemenoff, Raphael; Henson, Peter M; Holland, Steven M; Bratton, Donna L

2015-02-01

Deficient production of reactive oxygen species (ROS) by the phagocyte nicotinamide adenine dinucleotide (NADPH) oxidase in patients with chronic granulomatous disease (CGD) results in susceptibility to certain pathogens secondary to impaired oxidative killing and mobilization of other phagocyte defenses. Peroxisome proliferator-activated receptor (PPAR) γ agonists, including pioglitazone, approved for type 2 diabetes therapy alter cellular metabolism and can heighten ROS production. It was hypothesized that pioglitazone treatment of gp91(phox-/-) mice, a murine model of human CGD, would enhance phagocyte oxidant production and killing of Staphylococcus aureus, a significant pathogen in patients with this disorder. We sought to determine whether pioglitazone treatment of gp91(phox-/-) mice enhanced phagocyte oxidant production and host defense. Wild-type and gp91(phox-/-) mice were treated with the PPARγ agonist pioglitazone, and phagocyte ROS and killing of S aureus were investigated. As demonstrated by 3 different ROS-sensing probes, short-term treatment of gp91(phox-/-) mice with pioglitazone enhanced stimulated ROS production in neutrophils and monocytes from blood and neutrophils and inflammatory macrophages recruited to tissues. Mitochondria were identified as the source of ROS. Findings were replicated in human monocytes from patients with CGD after ex vivo pioglitazone treatment. Importantly, although mitochondrial (mt)ROS were deficient in gp91(phox-/-) phagocytes, their restoration with treatment significantly enabled killing of S aureus both ex vivo and in vivo. Together, the data support the hypothesis that signaling from the NADPH oxidase under normal circumstances governs phagocyte mtROS production and that such signaling is lacking in the absence of a functioning phagocyte oxidase. PPARγ agonism appears to bypass the need for the NADPH oxidase for enhanced mtROS production and partially restores host defense in CGD. Copyright © 2014 American Academy of Allergy, Asthma & Immunology. Published by Elsevier Inc. All rights reserved.

Arabidopsis MLO2 is a negative regulator of sensitivity to extracellular reactive oxygen species.

PubMed

Cui, Fuqiang; Wu, Hongpo; Safronov, Omid; Zhang, Panpan; Kumar, Rajeev; Kollist, Hannes; Salojärvi, Jarkko; Panstruga, Ralph; Overmyer, Kirk

2018-04-01

The atmospheric pollutant ozone (O 3 ) is a strong oxidant that causes extracellular reactive oxygen species (ROS) formation, has significant ecological relevance, and is used here as a non-invasive ROS inducer to study plant signalling. Previous genetic screens identified several mutants exhibiting enhanced O 3 sensitivity, but few with enhanced tolerance. We found that loss-of-function mutants in Arabidopsis MLO2, a gene implicated in susceptibility to powdery mildew disease, exhibit enhanced dose-dependent tolerance to O 3 and extracellular ROS, but a normal response to intracellular ROS. This phenotype is increased in a mlo2 mlo6 mlo12 triple mutant, reminiscent of the genetic redundancy of MLO genes in powdery mildew resistance. Stomatal assays revealed that enhanced O 3 tolerance in mlo2 mutants is not caused by altered stomatal conductance. We explored modulation of the mlo2-associated O 3 tolerance, powdery mildew resistance, and early senescence phenotypes by genetic epistasis analysis, involving mutants with known effects on ROS sensitivity or antifungal defence. Mining of publicly accessible microarray data suggests that these MLO proteins regulate accumulation of abiotic stress response transcripts, and transcript accumulation of MLO2 itself is O 3 responsive. In summary, our data reveal MLO2 as a novel negative regulator in plant ROS responses, which links biotic and abiotic stress response pathways. © 2018 John Wiley & Sons Ltd.

Oxidative changes and apoptosis induced by 1800-MHz electromagnetic radiation in NIH/3T3 cells.

PubMed

Hou, Qingxia; Wang, Minglian; Wu, Shuicai; Ma, Xuemei; An, Guangzhou; Liu, Huan; Xie, Fei

2015-03-01

To investigate the potential adverse effects of mobile phone radiation, we studied reactive oxygen species (ROS), DNA damage and apoptosis in mouse embryonic fibroblasts (NIH/3T3) after intermittent exposure (5 min on/10 min off, for various durations from 0.5 to 8 h) to an 1800-MHz GSM-talk mode electromagnetic radiation (EMR) at an average specific absorption rate of 2 W/kg. A 2',7'-dichlorofluorescin diacetate fluorescence probe was used to detect intracellular ROS levels, immunofluorescence was used to detect γH2AX foci as a marker for DNA damage, and flow cytometry was used to measure apoptosis. Our results showed a significant increase in intracellular ROS levels after EMR exposure and it reached the highest level at an exposure time of 1 h (p < 0.05) followed by a slight decrease when the exposure continued for as long as 8 h. No significant effect on the number of γH2AX was detected after EMR exposure. The percentage of late-apoptotic cells in the EMR-exposed group was significantly higher than that in the sham-exposed groups (p < 0.05). These results indicate that an 1800-MHz EMR enhances ROS formation and promotes apoptosis in NIH/3T3 cells.

Responses of Solid Tumor Cells in DMEM to Reactive Oxygen Species Generated by Non-Thermal Plasma and Chemically Induced ROS Systems

PubMed Central

Kaushik, Neha; Uddin, Nizam; Sim, Geon Bo; Hong, Young June; Baik, Ku Youn; Kim, Chung Hyeok; Lee, Su Jae; Kaushik, Nagendra Kumar; Choi, Eun Ha

2015-01-01

In this study, we assessed the role of different reactive oxygen species (ROS) generated by soft jet plasma and chemical-induced ROS systems with regard to cell death in T98G, A549, HEK293 and MRC5 cell lines. For a comparison with plasma, we generated superoxide anion (O2−), hydroxyl radical (HO·), and hydrogen peroxide (H2O2) with chemicals inside an in vitro cell culture. Our data revealed that plasma decreased the viability and intracellular ATP values of cells and increased the apoptotic population via a caspase activation mechanism. Plasma altered the mitochondrial membrane potential and eventually up-regulated the mRNA expression levels of BAX, BAK1 and H2AX gene but simultaneously down-regulated the levels of Bcl-2 in solid tumor cells. Moreover, a western blot analysis confirmed that plasma also altered phosphorylated ERK1/2/MAPK protein levels. At the same time, using ROS scavengers with plasma, we observed that scavengers of HO· (mannitol) and H2O2 (catalase and sodium pyruvate) attenuated the activity of plasma on cells to a large extent. In contrast, radicals generated by specific chemical systems enhanced cell death drastically in cancer as well as normal cell lines in a dose-dependent fashion but not specific with regard to the cell type as compared to plasma. PMID:25715710

Responses of Solid Tumor Cells in DMEM to Reactive Oxygen Species Generated by Non-Thermal Plasma and Chemically Induced ROS Systems

NASA Astrophysics Data System (ADS)

Kaushik, Neha; Uddin, Nizam; Sim, Geon Bo; Hong, Young June; Baik, Ku Youn; Kim, Chung Hyeok; Lee, Su Jae; Kaushik, Nagendra Kumar; Choi, Eun Ha

2015-02-01

In this study, we assessed the role of different reactive oxygen species (ROS) generated by soft jet plasma and chemical-induced ROS systems with regard to cell death in T98G, A549, HEK293 and MRC5 cell lines. For a comparison with plasma, we generated superoxide anion (O2-), hydroxyl radical (HO.), and hydrogen peroxide (H2O2) with chemicals inside an in vitro cell culture. Our data revealed that plasma decreased the viability and intracellular ATP values of cells and increased the apoptotic population via a caspase activation mechanism. Plasma altered the mitochondrial membrane potential and eventually up-regulated the mRNA expression levels of BAX, BAK1 and H2AX gene but simultaneously down-regulated the levels of Bcl-2 in solid tumor cells. Moreover, a western blot analysis confirmed that plasma also altered phosphorylated ERK1/2/MAPK protein levels. At the same time, using ROS scavengers with plasma, we observed that scavengers of HO. (mannitol) and H2O2 (catalase and sodium pyruvate) attenuated the activity of plasma on cells to a large extent. In contrast, radicals generated by specific chemical systems enhanced cell death drastically in cancer as well as normal cell lines in a dose-dependent fashion but not specific with regard to the cell type as compared to plasma.

Targeting human 8-oxoguanine DNA glycosylase to mitochondria protects cells from high glucose-induced apoptosis.

PubMed

Zou, Yu-Ling; Luo, Wen-Bin; Xie, Lin; Mao, Xin-Bang; Wu, Chao; You, Zhi-Peng

2018-06-01

Diabetic retinopathy (DR) is a major vision threatening disease mainly induced by high glucose. Despite great efforts were made to explore the etiology of DR, the exact mechanism responsible for its pathogenesis remains elusive. In our study, we constructed diabetic rats via Streptozotocin (STZ) injection. TUNEL assay was employed to examine retinal cell apoptosis. The levels of mitochondrial membrane potential (MMP) and reactive oxygen species (ROS) were analyzed via flow cytometry. The mRNA and protein levels of mitochondrial respiratory chain were investigated by RT-qPCR and western blot. Compared with normal rats, the retinal cell apoptosis rate in diabetic rats was significantly upregulated. What's more, the signals of 8-OHdG and the levels of Cytochrome C in diabetic rats were enhanced; however, the MnSOD signals and NADPH-1 levels were reduced. We investigated the effect of mitochondrialy targeted hOGG1 (MTS-hOGG1) on the primary rRECs under high glucose. Compared with vector-transfected cells, MTS-hOGG1-expressing cells blocked high glucose-induced cell apoptosis, the loss of MMP and the overproduction of ROS. In addition, under high glucose, MTS-hOGG1 transfection blocked the expression of Cytochrome C, but enhanced the expression of cytochrome c oxidase subunit 1 and NADPH-1. These findings indicated that high glucose induced cell apoptosis by causing the loss of MMP, the overproduction of ROS and mtDNA damage. Targeting DNA repair enzymes hOGG1 in mitochondria partly mitigated the high glucose-induced consequences, which shed new light for DR therapy.

Hydrogen cyanamide breaks grapevine bud dormancy in the summer through transient activation of gene expression and accumulation of reactive oxygen and nitrogen species.

PubMed

Sudawan, Boonyawat; Chang, Chih-Sheng; Chao, Hsiu-Fung; Ku, Maurice S B; Yen, Yung-Fu

2016-09-15

Hydrogen cyanamide (HC) and pruning (P) have frequently been used to break dormancy in grapevine floral buds. However, the exact underlying mechanism remains elusive. This study aimed to address the early mode of action of these treatments on accumulation of reactive oxygen species (ROS) and reactive nitrogen species (RNS) and expression of related genes in the dormancy breaking buds of grapevine in the summer. The budbreak rates induced by pruning (P), hydrogen cyanamide (HC), pruning plus hydrogen cyanamide (PHC) and water (control) after 8 days were 33, 53, 95, and 0 %, respectively. Clearly, HC was more effective in stimulating grapevine budbreak and P further enhanced its potency. In situ staining of longitudinal bud sections after 12 h of treatments detected high levels of ROS and nitric oxide (NO) accumulated in the buds treated with PHC, compared with HC or P alone. The amounts of ROS and NO accumulated were highly correlated with the rates of budbreak among these treatments, highlighting the importance of a rapid, transient accumulation of sublethal levels of ROS and RNS in dormancy breaking. Microarray analysis revealed specific alterations in gene expression in dormancy breaking buds induced by P, HC and PHC after 24 h of treatment. Relative to control, PHC altered the expression of the largest number of genes, while P affected the expression of the least number of genes. PHC also exerted a greater intensity in transcriptional activation of these genes. Gene ontology (GO) analysis suggests that alteration in expression of ROS related genes is the major factor responsible for budbreak. qRT-PCR analysis revealed the transient expression dynamics of 12 specific genes related to ROS generation and scavenge during the 48 h treatment with PHC. Our results suggest that rapid accumulation of ROS and NO at early stage is important for dormancy release in grapevine in the summer, and the identification of the commonly expressed specific genes among the treatments allowed the construction of the signal transduction pathway related to ROS/RNS metabolism during dormancy release. The rapid accumulation of a sublethal level of ROS/RNS subsequently induces cell wall loosening and expansion for bud sprouting.

Suppression of coenzyme Q₁₀ levels and the induction of multiple PDSS and COQ genes in human cells following oligomycin treatment.

PubMed

Yen, H-C; Liu, C-C; Kan, C-C; Chen, C-S; Wei, H-R

2014-09-01

Endogenous coenzyme Q10 (CoQ10) is a lipid-soluble antioxidant and essential for the electron transport chain. We previously demonstrated that hydrogen peroxide enhanced CoQ10 levels, whereas disruption of mitochondrial membrane potential by a chemical uncoupler suppressed CoQ10 levels, in human 143B cells. In this study, we investigated how CoQ10 levels and expression of two PDSS and eight COQ genes were affected by oligomycin, which inhibited ATP synthesis at Complex V without uncoupling the mitochondria. We confirmed that oligomycin increased the production of reactive oxygen species (ROS) and decreased mitochondria-dependent ATP production in 143B cells. We also demonstrated that CoQ10 levels were decreased by oligomycin after 42 or 48 h of treatment, but not at earlier time points. Expression of PDSS2 and COQ2-COQ9 were up-regulated after 18-hour oligomycin treatment, and the expression of PPARGC1A (PGC1-1α) elevated concurrently. Knockdown of PPARGC1A down-regulated the basal mRNA levels of PDSS2 and five COQ genes and suppressed the induction of COQ8 and COQ9 genes by oligomycin, but did not affect CoQ10 levels under these conditions. N-acetylcysteine suppressed the augmentation of ROS levels and the enhanced expression of COQ2, COQ4, COQ7, and COQ9 induced by oligomycin, but did not modulate the changes in CoQ10 levels. These results suggested that the condition of mitochondrial dysfunction induced by oligomycin decreased CoQ10 levels independent of oxidative stress. Up-regulation of PDSS2 and several COQ genes by oligomycin might be regulated by multiple mechanisms, including the signaling pathways mediated by PGC-1α and ROS, but it would not restore CoQ10 levels.

Hv1 proton channel facilitates production of ROS and pro-inflammatory cytokines in microglia and enhances oligodendrocyte progenitor cells damage from oxygen-glucose deprivation in vitro.

PubMed

Yu, Ying; Yu, Zhiyuan; Xie, Minjie; Wang, Wei; Luo, Xiang

2018-03-25

The contribution of microglial activation to oligodendrocyte precursor cell (OPC) damage in the brain is considered to be a principal pathophysiological feature of periventricular leukomalacia (PVL). Nicotinamide adenine dinucleotide phosphate oxidase (NOX)-dependent reactive oxygen species (ROS) produced in microglia has been shown to be significantly toxic to OPCs. The voltage-gated proton channel Hv1 is selectively expressed in microglia and is essential for NOX-dependent ROS production in the central nervous system. This study aimed to investigate the effects of microglial Hv1 deficiency on the protection of OPCs from oxygen-glucose deprivation (OGD)-induced injury in vitro. In the present study, the levels of OGD-induced ROS and pro-inflammatory cytokine production were dramatically lower in Hv1-deficient microglia (Hv1 -/- ) than in wild-type (WT) microglia. Following OGD, OPCs co-cultured with WT microglia had increased apoptosis and decreased proliferation and maturation, while those co-cultured with Hv1 -/- microglia had attenuated apoptosis and greater proliferation and differentiation. Furthermore, the attenuated damage and enhanced regeneration of OPCs were associated with decreases in extracellular signal-regulated kinase 1/2 and p38 mitogen-activated protein kinase phosphorylation. These results indicate that the protective effects of Hv1 deficiency on OPCs are due to the suppression of ROS and pro-inflammatory cytokine production in microglia. We thus suggest that the microglial proton channel Hv1 may be a potential therapeutic target in PVL. Copyright © 2017 Elsevier Inc. All rights reserved.

Human Mut T Homolog 1 (MTH1): a roadblock for the tumor-suppressive effects of oncogenic RAS-induced ROS.

PubMed

Rai, Priyamvada

2012-01-01

Oncogenic RAS-induced reactive oxygen species (ROS) trigger barriers to cell transformation and cancer progression through tumor-suppressive responses such as cellular senescence or cell death. We have recently shown that oncogenic RAS-induced DNA damage and attendant premature senescence can be prevented by overexpressing human MutT Homolog 1 (MTH1), the major mammalian detoxifier of the oxidized DNA precursor, 8-oxo-dGTP. Paradoxically, RAS-induced ROS are also able to participate in tumor progression via transformative processes such as mitogenic signaling, the epithelial-mesenchymal transition (EMT), anoikis inhibition, and PI3K/Akt-mediated survival signaling. Here we provide a preliminary insight into the influence of MTH1 levels on the EMT phenotype and Akt activation in RAS-transformed HMLE breast epithelial cells. Within this context, we will discuss the implications of MTH1 upregulation in oncogenic RAS-sustaining cells as a beneficial adaptive change that inhibits ROS-mediated cell senescence and participates in the maintenance of ROS-associated tumor-promoting mechanisms. Accordingly, targeting MTH1 in RAS-transformed tumor cells will not only induce proliferative defects but also potentially enhance therapeutic cytotoxicity by shifting cellular response away from pro-survival mechanisms.

Dynamin-related protein inhibitor downregulates reactive oxygen species levels to indirectly suppress high glucose-induced hyperproliferation of vascular smooth muscle cells

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

Maimaitijiang, Alimujiang; Zhuang, Xinyu; Jiang, Xiaofei

Hyperproliferation of vascular smooth muscle cells is a pathogenic mechanism common in diabetic vascular complications and is a putatively important therapeutic target. This study investigated multiple levels of biology, including cellular and organellar changes, as well as perturbations in protein synthesis and morphology. Quantitative and qualitative analysis was utilized to assess the effect of mitochondrial dynamic changes and reactive oxygen species(ROS) levels on high-glucose-induced hyperproliferation of vascular smooth muscle cells. The data demonstrated that the mitochondrial fission inhibitor Mdivi-1 and downregulation of ROS levels both effectively inhibited the high-glucose-induced hyperproliferation of vascular smooth muscle cells. Downregulation of ROS levels playedmore » a more direct role and ROS levels were also regulated by mitochondrial dynamics. Increased ROS levels induced excessive mitochondrial fission through dynamin-related protein (Drp 1), while Mdivi-1 suppressed the sensitivity of Drp1 to ROS levels, thus inhibiting excessive mitochondrial fission under high-glucose conditions. This study is the first to propose that mitochondrial dynamic changes and ROS levels interact with each other and regulate high-glucose-induced hyperproliferation of vascular smooth muscle cells. This finding provides novel ideas in understanding the pathogenesis of diabetic vascular remodeling and intervention. - Highlights: • Mdivi-1 inhibits VSMC proliferation by lowering ROS level in high-glucose condition. • ROS may be able to induce mitochondrial fission through Drp1 regulation. • Mdivi-1 can suppress the sensitivity of Drp1 to ROS.« less

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

PubMed Central

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

2014-01-01

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

Different effects of two cyclic chalcone analogues on redox status of Jurkat T cells.

PubMed

Rozmer, Zsuzsanna; Berki, Tímea; Maász, Gábor; Perjési, Pál

2014-12-01

Chalcones are intermediary compounds of the biosynthetic pathway of the naturally flavonoids. Previous studies have demonstrated that chalcones and their conformationally rigid cyclic analogues have tumour cell cytotoxic and chemopreventive effects. It has been shown that equitoxic doses of the two cyclic chalcone analogues (E)-2-(4'-methoxybenzylidene)-(2) and (E)-2-(4'-methylbenzylidene)-1-benzosuberone (3) have different effect on cell cycle progress of the investigated Jurkat cells. It was also found that the compounds affect the cellular thiol status of the treated cells and show intrinsic (non-enzyme-catalyzed) reactivity towards GSH under cell-free conditions. In order to gain new insights into the cytotoxic mechanism of the compounds, effects on the redox status and glutathione level of Jurkat cells were investigated. Detection of intracellular ROS level in Jurkat cells exposed to 2 and 3 was performed using the dichlorofluorescein-assay. Compound 2 did not influence ROS activity either on 1 or 4h exposure; in contrast, chalcone 3 showed to reduce ROS level at both timepoints. The two compounds had different effects on cellular glutathione status as well. Compound 2 significantly increased the oxidized glutathione (GSSG) level showing an interference with the cellular antioxidant defence. On the contrary, chalcone 3 enhanced the reduced glutathione level, indicating enhanced cellular antioxidant activity. To investigate the chalcone-GSH conjugation reactions under cellular conditions, a combination of a RP-HPLC method with electrospray ionization mass spectrometry (ESI-MS) was performed. Chalcone-GSH adducts could not be observed either in the cell supernatant or the cell sediment after deproteinization. The investigations provide further details of dual - cytotoxic and chemopreventive - effects of the cyclic chalcone analogues. Copyright © 2014 Elsevier Ltd. All rights reserved.

Apigenin induces both intrinsic and extrinsic pathways of apoptosis in human colon carcinoma HCT-116 cells.

PubMed

Wang, Bo; Zhao, Xin-Huai

2017-02-01

Apigenin is one of the plant-originated flavones with anticancer activities. In this study, apigenin was assessed for its in vitro effects on a human colon carcinoma line (HCT‑116 cells) in terms of anti-proliferation, cell cycle progression arrest, apoptosis and intracellular reactive oxygen species (ROS) generation, and then outlined its possible apoptotic mechanism for the cells. Apigenin exerted cytotoxic effect on the cells via inhibiting cell growth in a dose-time-dependent manner and causing morphological changes, arrested cell cycle progression at G0/G1 phase, and decreased mitochondrial membrane potential of the treated cells. Apigenin increased respective ROS generation and Ca2+ release and thereby, caused ER stress in the treated cells. Apigenin shows apoptosis induction towards the cells, resulting in enhanced portion of apoptotic cells. A mechanism involved ROS generation and endoplasmic reticulum stress was outlined for the apigenin-mediated apoptosis via both intrinsic mitochondrial and extrinsic pathways, based on the assayed mRNA and protein expression levels in the cells. With this mechanism, apigenin resulted in the HCT-116 cells with enhanced intracellular ROS generation and Ca2+ release together with damaged mitochondrial membrane, and upregulated protein expression of CHOP, DR5, cleaved BID, Bax, cytochrome c, cleaved caspase-3, cleaved caspase-8 and cleaved caspase-9, which triggered apoptosis of the cells.

Activation of ethylene signaling pathways enhances disease resistance by regulating ROS and phytoalexin production in rice.

PubMed

Yang, Chao; Li, Wen; Cao, Jidong; Meng, Fanwei; Yu, Yongqi; Huang, Junkai; Jiang, Lan; Liu, Muxing; Zhang, Zhengguang; Chen, Xuewei; Miyamoto, Koji; Yamane, Hisakazu; Zhang, Jinsong; Chen, Shouyi; Liu, Jun

2017-01-01

Ethylene plays diverse roles in plant growth, development and stress responses. However, the roles of ethylene signaling in immune responses remain largely unknown. In this study, we showed that the blast fungus Magnaporthe oryzae infection activated ethylene biosynthesis in rice. Resistant rice cultivars accumulated higher levels of ethylene than susceptible ones. Ethylene signaling components OsEIN2 and the downstream transcription factor OsEIL1 positively regulated disease resistance. Mutation of OsEIN2 led to enhanced disease susceptibility. Whole-genome transcription analysis revealed that responsive genes of ethylene, jasmonates (JAs) and reactive oxygen species (ROS) signaling as well as phytoalexin biosynthesis genes were remarkably induced. Transcription of OsrbohA/B, which encode NADPH oxidases, and OsOPRs, the JA biosynthesis genes, were induced by M. oryzae infection. Furthermore, we demonstrated that OsEIL1 binds to the promoters of OsrbohA/OsrbohB and OsOPR4 to activate their expression. These data suggest that OsEIN2-mediated OsrbohA/OsrbohB and OsOPR transcription may play essential roles in ROS generation, JA biosynthesis and the subsequent phytoalexin accumulation. Therefore, the involvement of ethylene signaling in disease resistance is probably by activation of ROS and phytoalexin production in rice during M. oryzae infection. © 2016 The Authors The Plant Journal © 2016 John Wiley & Sons Ltd.

Mitochondrial reactive oxygen species (ROS) as signaling molecules of intracellular pathways triggered by the cardiac renin-angiotensin II-aldosterone system (RAAS)

PubMed Central

De Giusti, V. C.; Caldiz, C. I.; Ennis, I. L.; Pérez, N. G.; Cingolani, H. E.; Aiello, E. A.

2013-01-01

Mitochondria represent major sources of basal reactive oxygen species (ROS) production of the cardiomyocyte. The role of ROS as signaling molecules that mediate different intracellular pathways has gained increasing interest among physiologists in the last years. In our lab, we have been studying the participation of mitochondrial ROS in the intracellular pathways triggered by the renin-angiotensin II-aldosterone system (RAAS) in the myocardium during the past few years. We have demonstrated that acute activation of cardiac RAAS induces mitochondrial ATP-dependent potassium channel (mitoKATP) opening with the consequent enhanced production of mitochondrial ROS. These oxidant molecules, in turn, activate membrane transporters, as sodium/hydrogen exchanger (NHE-1) and sodium/bicarbonate cotransporter (NBC) via the stimulation of the ROS-sensitive MAPK cascade. The stimulation of such effectors leads to an increase in cardiac contractility. In addition, it is feasible to suggest that a sustained enhanced production of mitochondrial ROS induced by chronic cardiac RAAS, and hence, chronic NHE-1 and NBC stimulation, would also result in the development of cardiac hypertrophy. PMID:23755021

Mitochondrial reactive oxygen species (ROS) as signaling molecules of intracellular pathways triggered by the cardiac renin-angiotensin II-aldosterone system (RAAS).

PubMed

De Giusti, V C; Caldiz, C I; Ennis, I L; Pérez, N G; Cingolani, H E; Aiello, E A

2013-01-01

Mitochondria represent major sources of basal reactive oxygen species (ROS) production of the cardiomyocyte. The role of ROS as signaling molecules that mediate different intracellular pathways has gained increasing interest among physiologists in the last years. In our lab, we have been studying the participation of mitochondrial ROS in the intracellular pathways triggered by the renin-angiotensin II-aldosterone system (RAAS) in the myocardium during the past few years. We have demonstrated that acute activation of cardiac RAAS induces mitochondrial ATP-dependent potassium channel (mitoKATP) opening with the consequent enhanced production of mitochondrial ROS. These oxidant molecules, in turn, activate membrane transporters, as sodium/hydrogen exchanger (NHE-1) and sodium/bicarbonate cotransporter (NBC) via the stimulation of the ROS-sensitive MAPK cascade. The stimulation of such effectors leads to an increase in cardiac contractility. In addition, it is feasible to suggest that a sustained enhanced production of mitochondrial ROS induced by chronic cardiac RAAS, and hence, chronic NHE-1 and NBC stimulation, would also result in the development of cardiac hypertrophy.

Biophysical characterization of functionalized titania nanoparticles and their application in dental adhesives.

PubMed

Sun, Jirun; Petersen, Elijah J; Watson, Stephanie S; Sims, Christopher M; Kassman, Alexander; Frukhtbeyn, Stanislav; Skrtic, Drago; Ok, Meryem T; Jacobs, Debbie S; Reipa, Vytas; Ye, Qiang; Nelson, Bryant C

2017-04-15

It is demonstrated that carboxylic acid-functionalized titanium dioxide (TiO 2 ) NPs produce significantly higher levels of reactive oxygen species (ROS) after visible light irradiation (400-800nm, 1600mW/cm 2 ) in comparison to nonfunctionalized TiO 2 NPs. The level of ROS produced under these irradiation conditions was not capable of generating oxidatively induced DNA damage in a cell-free system for TiO 2 concentrations of 0.5mg/L or 5mg/L. In addition, specific incorporation of the acrylic acid-functionalized TiO 2 NPs into dental composites allowed us to utilize the generated ROS to enhance photopolymerization (curing and degree of vinyl conversion (DC)) of resin adhesives and create mechanically superior and biocompatible materials for dental applications. Incorporation of the TiO 2 NPs into selected dental composites increased the mean DC values by ≈7%. The modified TiO 2 materials and dental composite materials were extensively characterized using thermogravimetric analysis, electron microscopy, Fourier transform infrared spectroscopy, and electron paramagnetic resonance. Notably, dental adhesives incorporated with acrylic acid-functionalized TiO 2 NPs produced stronger bonds to human teeth following visible light curing in comparison to traditional dental adhesives not containing NPs with an increase in the shear bond strength of ≈29%. In addition, no leaching of the incorporated NPs was detectable from the dental adhesives after 2500 thermal cycles using inductively coupled plasma-optical emission spectroscopy, indicating that biocompatibility of the adhesives was not compromised after extensive aging. These findings suggest that NP-induced ROS may be useful to produce enhanced nanocomposite materials for selected applications in the medical device field. Titanium dioxide nanoparticles (TiO 2 NPs) have unique photocatalytic, antibacterial and UV-absorbing properties that make them beneficial additives in adhesives and composites. However, there is concern that the reactive oxygen species (ROS) produced by photoactivated TiO 2 NPs might pose toxicological risks. We demonstrate that it is possible to incorporate acid-functionalized TiO 2 NPs into dental resins which can be applied as dental adhesives to human teeth. The ROS generated by these NPs through visible-light irradiation may be utilized to increase the degree of vinyl conversion of resins, leading to adhesives that have an enhanced shear-bond strength to human teeth. Investigation into the potential genotoxicity of the NPs and their potential for release from dental composites indicated a low risk of genotoxic effects. Published by Elsevier Ltd.

Whey protein enhances normal inflammatory responses during cutaneous wound healing in diabetic rats

PubMed Central

2011-01-01

Background Prolonged wound healing is a complication of diabetes that contributes to mortality. Impaired wound healing occurs as a consequence of excessive reactive oxygen species (ROS) production. Whey protein (WP) is able to reduce the oxygen radicals and increase the levels of the antioxidant glutathione. Thus, the aim of this study was to determine whether dietary supplementation with WP could enhance normal inflammatory responses during wound healing in diabetic rats. Animals were assigned into a wounded control group (WN), a wounded diabetic group (WD) and a wounded diabetic group orally supplemented with whey protein (WDWP) at a dose of 100 mg/kg body weight. Results Whey protein was found to significantly decrease the levels of malondialdehyde (MDA), nitric oxide (NO) and ROS. A significant restoration of the glutathione level was observed in WDWP rats. During the early wound healing stage, IL-1β, TNF-α, IL-6, IL-4 and neutrophil infiltration were significantly decreased in WD mice. WP supplementation was found to restore the levels of these inflammatory markers to the levels observed in control animals. In addition, the time required for wound healing was significantly prolonged in diabetic rats. WP was found to significantly decrease the time required for wound healing in WDWP rats. Conclusion In conclusion, dietary supplementation with WP enhances the normal inflammatory responses during wound healing in diabetic mice by restoring the levels of oxidative stress and inflammatory cytokines. PMID:22168406

Light irradiation helps magnetotactic bacteria eliminate intracellular reactive oxygen species.

PubMed

Li, Kefeng; Wang, Pingping; Chen, Chuanfang; Chen, Changyou; Li, Lulu; Song, Tao

2017-09-01

Magnetotactic bacteria (MTB) demonstrate photoresponse. However, little is known about the biological significance of this behaviour. Magnetosomes exhibit peroxidase-like activity and can scavenge reactive oxygen species (ROS). Magnetosomes extracted from the Magnetospirillum magneticum strain AMB-1 show enhanced peroxidase-like activity under illumination. The present study investigated the effects of light irradiation on nonmagnetic (without magnetosomes) and magnetic (with magnetosomes) AMB-1 cells. Results showed that light irradiation did not affect the growth of nonmagnetic and magnetic cells but significantly increased magnetosome synthesis and reduced intracellular ROS level in magnetic cells. Quantitative reverse transcription polymerase chain reaction (qRT-PCR) was performed to analyse the expression level of magnetosome formation-associated genes (mamA, mms6, mms13 and mmsF) and stress-related genes (recA, oxyR, SOD, amb0664 and amb2684). Results showed that light irradiation upregulated the expression of mms6, mms13 and mmsF. Furthermore, light irradiation upregulated the expression of stress-related genes in nonmagnetic cells but downregulated them in magnetic cells. Additionally, magnetic cells exhibited stronger phototactic behaviour than nonmagnetic ones. These results suggested that light irradiation could heighten the ability of MTB to eliminate intracellular ROS and help them adapt to lighted environments. This phenomenon may be related to the enhanced peroxidase-like activity of magnetosomes under light irradiation. © 2017 Society for Applied Microbiology and John Wiley & Sons Ltd.

The Induction of Pattern-Recognition Receptor Expression against Influenza A Virus through Duox2-Derived Reactive Oxygen Species in Nasal Mucosa.

PubMed

Kim, Hyun Jik; Kim, Chang-Hoon; Kim, Min-Ji; Ryu, Ji-Hwan; Seong, Sang Yeop; Kim, Sujin; Lim, Su Jin; Holtzman, Michael J; Yoon, Joo-Heon

2015-10-01

We studied the relative roles of Duox2-derived reactive oxygen species (ROS) in host defense against influenza A virus (IAV) infection in normal human nasal epithelial cells and mouse nasal mucosa. We found that Duox2 primarily generated ROS rapidly after IAV infection in normal human nasal epithelial cells and that knockdown of Duox2 aggravated IAV infection. In addition, Duox2-derived ROS enhancement significantly suppressed IAV infection in nasal epithelium. In particular, Duox2-derived ROS were required for the induction of retinoic acid-inducible gene (RIG)-I and melanoma differentiation-associated protein 5 (MDA5) transcription. After intranasal IAV inoculation into mice, viral infection was significantly aggravated from 3 days postinoculation (dpi) in the nasal mucosa, and the IAV viral titer was highest at 7 dpi. Both RIG-I and MDA5 messenger RNA levels increased dominantly in mouse nasal mucosa from 3 dpi; consistent with this, RIG-I and MDA5 proteins were also induced after IAV infection. RIG-I and MDA5 messenger RNA levels were induced to a lower extent in the nasal mucosa of the mice that were inoculated with Duox2 short hairpin RNA, and the IAV viral titer was significantly higher in nasal lavage. Taken together, Duox2-derived ROS are necessary for the innate immune response and trigger the induction of RIG-I and MDA5 to resist IAV infection in human nasal epithelium and mouse nasal mucosa.

Opposite effects of statins on mitochondria of cardiac and skeletal muscles: a ‘mitohormesis’ mechanism involving reactive oxygen species and PGC-1

PubMed Central

Bouitbir, Jamal; Charles, Anne-Laure; Echaniz-Laguna, Andoni; Kindo, Michel; Daussin, Frédéric; Auwerx, Johan; Piquard, François; Geny, Bernard; Zoll, Joffrey

2012-01-01

Aims Statins protect against cardiovascular-related mortality but induce skeletal muscle toxicity. To investigate mechanisms of statins, we tested the hypothesis that statins optimized cardiac mitochondrial function but impaired vulnerable skeletal muscle by inducing different level of reactive oxygen species (ROS). Methods and results In atrium of patients treated with statins, ROS production was decreased and oxidative capacities were enhanced together with an extensive augmentation of mRNAs expression of peroxisome proliferator-activated receptor gamma co-activator (PGC-1) family. However, in deltoid biopsies from patients with statin-induced muscular myopathy, oxidative capacities were decreased together with ROS increase and a collapse of PGC-1 mRNA expression. Several animal and cell culture experiments were conducted and showed by using ROS scavengers that ROS production was the triggering factor responsible of atorvastatin-induced activation of mitochondrial biogenesis pathway and improvement of antioxidant capacities in heart. Conversely, in skeletal muscle, the large augmentation of ROS production following treatment induced mitochondrial impairments, and reduced mitochondrial biogenesis mechanisms. Quercetin, an antioxidant molecule, was able to counteract skeletal muscle deleterious effects of atorvastatin in rat. Conclusion Our findings identify statins as a new activating factor of cardiac mitochondrial biogenesis and antioxidant capacities, and suggest the importance of ROS/PGC-1 signalling pathway as a key element in regulation of mitochondrial function in cardiac as well as skeletal muscles. PMID:21775390

Seawater inhalation induces acute lung injury via ROS generation and the endoplasmic reticulum stress pathway.

PubMed

Li, Peng-Cheng; Wang, Bo-Rong; Li, Cong-Cong; Lu, Xi; Qian, Wei-Sheng; Li, Yu-Juan; Jin, Fa-Guang; Mu, De-Guang

2018-05-01

Seawater (SW) inhalation can induce acute lung injury (ALI) and acute respiratory distress syndrome (ARDS). In the present study, SW induced apoptosis of rat alveolar epithelial cells and histopathological alterations to lung tissue. Furthermore, SW administration increased generation of reactive oxygen species (ROS), whereas pretreatment with the ROS scavenger, N‑acetyl‑L‑cysteine (NAC), significantly decreased ROS generation, apoptosis and histopathological alterations. In addition, SW exposure upregulated the expression levels of glucose‑regulated protein 78 (GRP78) and CCAAT/enhancer binding protein homologous protein (CHOP), which are critical proteins in the endoplasmic reticulum (ER) stress response, thus indicating that SW may activate ER stress. Conversely, blocking ER stress with 4‑phenylbutyric acid (4‑PBA) significantly improved SW‑induced apoptosis and histopathological alterations, whereas an ER stress inducer, thapsigargin, had the opposite effect. Furthermore, blocking ROS with NAC inhibited SW‑induced ER stress, as evidenced by the downregulation of GRP78, phosphorylated (p)‑protein kinase R‑like ER kinase (PERK), p‑inositol‑requiring kinase 1α (IRE1α), p‑50 activating transcription factor 6α and CHOP. In addition, blocking ER stress with 4‑PBA decreased ROS generation. In conclusion, the present study indicated that ROS and ER stress pathways, which are involved in alveolar epithelial cell apoptosis, are important in the pathogenesis of SW‑induced ALI.

Reactive oxygen species enhance insulin sensitivity

PubMed Central

Loh, Kim; Deng, Haiyang; Fukushima, Atsushi; Cai, Xiaochu; Boivin, Benoit; Galic, Sandra; Bruce, Clinton; Shields, Benjamin J.; Skiba, Beata; Ooms, Lisa M.; Stepto, Nigel; Wu, Ben; Mitchell, Christina A.; Tonks, Nicholas K.; Watt, Matthew J.; Febbraio, Mark A.; Crack, Peter J.; Andrikopoulos, Sofianos; Tiganis, Tony

2010-01-01

SUMMARY Chronic reactive oxygen species (ROS) production by mitochondria may contribute to the development of insulin resistance, a primary feature of type 2 diabetes. In recent years it has become apparent that ROS generation in response to physiological stimuli such as insulin may also facilitate signaling by reversibly oxidizing and inhibiting protein tyrosine phosphatases (PTPs). Here we report that mice lacking one of the key enzymes involved in the elimination of physiological ROS, glutathione peroxidase 1 (Gpx1), were protected from high fat diet-induced insulin resistance. The increased insulin sensitivity in Gpx1−/− mice was attributed to insulin-induced phosphatidylinositol-3-kinase/Akt signaling and glucose uptake in muscle and could be reversed by the anti-oxidant N-acetylcysteine. Increased insulin signaling correlated with enhanced oxidation of the PTP family member PTEN, which terminates signals generated by phosphatidylinositol-3-kinase. These studies provide causal evidence for the enhancement of insulin signaling by ROS in vivo. PMID:19808019

Apolipoprotein E Genotype-Dependent Paradoxical Short-Term Effects of {sup 56}Fe Irradiation on the Brain

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

Haley, Gwendolen E.; Division of Neuroscience, Oregon National Primate Research Center, Beaverton, OR; Villasana, Laura

2012-11-01

Purpose: In humans, apolipoprotein E (apoE) is encoded by three major alleles ({epsilon}2, {epsilon}3, and {epsilon}4) and, compared to apoE3, apoE4 increases the risk of developing Alzheimer disease and cognitive impairments following various environmental challenges. Exposure to irradiation, including that of {sup 56}Fe, during space missions poses a significant risk to the central nervous system, and apoE isoform might modulate this risk. Methods and Materials: We investigated whether apoE isoform modulates hippocampus-dependent cognitive performance starting 2 weeks after {sup 56}Fe irradiation. Changes in reactive oxygen species (ROS) can affect cognition and are induced by irradiation. Therefore, after cognitive testing, wemore » assessed hippocampal ROS levels in ex vivo brain slices, using the ROS-sensitive fluorescent probe, dihydroethidium (DHE). Brain levels of 3-nitrotyrosine (3-NT), CuZn superoxide dismutase (CuZnSOD), extracellular SOD, and apoE were assessed using Western blotting analysis. Results: In the water maze, spatial memory retention was impaired by irradiation in apoE2 and apoE4 mice but enhanced by irradiation in apoE3 mice. Irradiation reduced DHE-oxidation levels in the enclosed blade of the dentate gyrus and levels of 3-NT and CuZnSOD in apoE2 but not apoE3 or apoE4 mice. Finally, irradiation increased apoE levels in apoE3 but not apoE2 or apoE4 mice. Conclusions: The short-term effects of {sup 56}Fe irradiation on hippocampal ROS levels and hippocampus-dependent spatial memory retention are apoE isoform-dependent.« less

Insulin Resistance in PCOS Patients Enhances Oxidative Stress and Leukocyte Adhesion: Role of Myeloperoxidase

PubMed Central

Victor, Victor M.; Rovira-Llopis, Susana; Bañuls, Celia; Diaz-Morales, Noelia; Martinez de Marañon, Arantxa; Rios-Navarro, Cesar; Alvarez, Angeles; Gomez, Marcelino; Rocha, Milagros; Hernández-Mijares, Antonio

2016-01-01

Cardiovascular diseases and oxidative stress are related to polycystic ovary syndrome (PCOS) and insulin resistance (IR). We have evaluated the relationship between myeloperoxidase (MPO) and leukocyte activation in PCOS patients according to homeostatic model assessment of IR (HOMA-IR), and have explored a possible correlation between these factors and endocrine and inflammatory parameters. This was a prospective controlled study conducted in an academic medical center. The study population consisted of 101 PCOS subjects and 105 control subjects. We divided PCOS subjects into PCOS non-IR (HOMA-IR<2.5) and PCOS IR (HOMA-IR>2.5). Metabolic and anthropometric parameters, total and mitochondrial reactive oxygen species (ROS) production, MPO levels, interactions between human umbilical vein endothelial cells and leukocytes, adhesion molecules (E-selectin, ICAM-1 and VCAM-1) and proinflammatory cytokines (IL-6 and TNF-α) were evaluated. Oxidative stress was observed in PCOS patients, in whom there was an increase in total and mitochondrial ROS production and MPO levels. Enhanced rolling flux and adhesion, and a decrease in polymorphonuclear cell rolling velocity were also detected in PCOS subjects. Increases in IL-6 and TNF-α and adhesion molecules (E-selectin, ICAM-1 and VCAM-1) were also observed, particularly in the PCOS IR group, providing evidence that inflammation and oxidative stress are related in PCOS patients. HOMA-IR was positively correlated with hsCRP (p<0.001, r = 0.304), ROS production (p<0.01, r = 0.593), leukocyte rolling flux (p<0.05, r = 0.446), E-selectin (p<0.01, r = 0.436) and IL-6 (p<0.001, r = 0.443). The results show an increase in the rate of ROS and MPO levels in PCOS patients in general, and particularly in those with IR. Inflammation in PCOS induces leukocyte-endothelium interactions and a simultaneous increase in IL-6, TNF-α, E-selectin, ICAM-1 and VCAM-1. These conditions are aggravated by the presence of IR. PMID:27007571

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.

In vitro acute exposure to DEHP affects oocyte meiotic maturation, energy and oxidative stress parameters in a large animal model.

PubMed

Ambruosi, Barbara; Uranio, Manuel Filioli; Sardanelli, Anna Maria; Pocar, Paola; Martino, Nicola Antonio; Paternoster, Maria Stefania; Amati, Francesca; Dell'Aquila, Maria Elena

2011-01-01

Phthalates are ubiquitous environmental contaminants because of their use in plastics and other common consumer products. Di-(2-ethylhexyl) phthalate (DEHP) is the most abundant phthalate and it impairs fertility by acting as an endocrine disruptor. The aim of the present study was to analyze the effects of in vitro acute exposure to DEHP on oocyte maturation, energy and oxidative status in the horse, a large animal model. Cumulus cell (CC) apoptosis and oxidative status were also investigated. Cumulus-oocyte complexes from the ovaries of slaughtered mares were cultured in vitro in presence of 0.12, 12 and 1200 µM DEHP. After in vitro maturation (IVM), CCs were removed and evaluated for apoptosis (cytological assessment and TUNEL) and intracellular reactive oxygen species (ROS) levels. Oocytes were evaluated for nuclear chromatin configuration. Matured (Metaphase II stage; MII) oocytes were further evaluated for cytoplasmic energy and oxidative parameters. DEHP significantly inhibited oocyte maturation when added at low doses (0.12 µM; P<0.05). This effect was related to increased CC apoptosis (P<0.001) and reduced ROS levels (P<0.0001). At higher doses (12 and 1200 µM), DEHP induced apoptosis (P<0.0001) and ROS increase (P<0.0001) in CCs without affecting oocyte maturation. In DEHP-exposed MII oocytes, mitochondrial distribution patterns, apparent energy status (MitoTracker fluorescence intensity), intracellular ROS localization and levels, mt/ROS colocalization and total SOD activity did not vary, whereas increased ATP content (P<0.05), possibly of glycolytic origin, was found. Co-treatment with N-Acetyl-Cysteine reversed apoptosis and efficiently scavenged excessive ROS in DEHP-treated CCs without enhancing oocyte maturation. In conclusion, acute in vitro exposure to DEHP inhibits equine oocyte maturation without altering ooplasmic energy and oxidative stress parameters in matured oocytes which retain the potential to be fertilized and develop into embryos even though further studies are necessary to confirm this possibility.

In Vitro Acute Exposure to DEHP Affects Oocyte Meiotic Maturation, Energy and Oxidative Stress Parameters in a Large Animal Model

PubMed Central

Sardanelli, Anna Maria; Pocar, Paola; Martino, Nicola Antonio; Paternoster, Maria Stefania; Amati, Francesca; Dell'Aquila, Maria Elena

2011-01-01

Phthalates are ubiquitous environmental contaminants because of their use in plastics and other common consumer products. Di-(2-ethylhexyl) phthalate (DEHP) is the most abundant phthalate and it impairs fertility by acting as an endocrine disruptor. The aim of the present study was to analyze the effects of in vitro acute exposure to DEHP on oocyte maturation, energy and oxidative status in the horse, a large animal model. Cumulus cell (CC) apoptosis and oxidative status were also investigated. Cumulus-oocyte complexes from the ovaries of slaughtered mares were cultured in vitro in presence of 0.12, 12 and 1200 µM DEHP. After in vitro maturation (IVM), CCs were removed and evaluated for apoptosis (cytological assessment and TUNEL) and intracellular reactive oxygen species (ROS) levels. Oocytes were evaluated for nuclear chromatin configuration. Matured (Metaphase II stage; MII) oocytes were further evaluated for cytoplasmic energy and oxidative parameters. DEHP significantly inhibited oocyte maturation when added at low doses (0.12 µM; P<0.05). This effect was related to increased CC apoptosis (P<0.001) and reduced ROS levels (P<0.0001). At higher doses (12 and 1200 µM), DEHP induced apoptosis (P<0.0001) and ROS increase (P<0.0001) in CCs without affecting oocyte maturation. In DEHP-exposed MII oocytes, mitochondrial distribution patterns, apparent energy status (MitoTracker fluorescence intensity), intracellular ROS localization and levels, mt/ROS colocalization and total SOD activity did not vary, whereas increased ATP content (P<0.05), possibly of glycolytic origin, was found. Co-treatment with N-Acetyl-Cysteine reversed apoptosis and efficiently scavenged excessive ROS in DEHP-treated CCs without enhancing oocyte maturation. In conclusion, acute in vitro exposure to DEHP inhibits equine oocyte maturation without altering ooplasmic energy and oxidative stress parameters in matured oocytes which retain the potential to be fertilized and develop into embryos even though further studies are necessary to confirm this possibility. PMID:22076161

Paradoxical effects of 137Cs irradiation on pharmacological stimulation of reactive oxygen species in hippocampal slices from apoE2 and apoE4 mice.

PubMed

Villasana, Laura E; Akinyeke, Tunde; Weber, Sydney; Raber, Jacob

2017-09-29

In humans, apoE, which plays a role in repair, is expressed in three isoforms: E2, E3, and E4. E4 is a risk factor for age-related cognitive decline (ACD) and Alzheimer's disease (AD), particularly in women. In contrast, E2 is a protective factor for ACD and AD. E2 and E4 might also differ in their response to cranial 137 Cs irradiation, a form of radiation typically used in a clinical setting for the treatment of cancer. This might be mediated by reactive oxygen species (ROS) in an-apoE isoform-dependent fashion. E2 and E4 female mice received sham-irradiation or cranial irradiation at 8 weeks of age and a standard mouse chow or a diet supplemented with the antioxidant alpha-lipoic acid (ALA) starting at 6 weeks of age. Behavioral and cognitive performance of the mice were assessed 12 weeks later. Subsequently, the generation of ROS in hippocampal slices was analyzed. Compared to sham-irradiated E4 mice, irradiated E4 mice showed enhanced spatial memory in the water maze. This was associated with increased hippocampal PMA-induction of ROS. Similar effects were not seen in E2 mice. Irradiation increased endogenous hippocampal ROS levels in E2 mice while decreasing those in E4 mice. NADPH activity and MnSOD levels were higher in sham-irradiated E2 than E4 mice. Irradiation increased NADPH activity and MnSOD levels in hemi brains of E4 mice but not in those of E2 mice. ALA did not affect behavioral and cognitive performance or hippocampal formation of ROS in either genotype. Thus, apoE isoforms modulate the radiation response.

Hyperglycemic Conditions Prime Cells for RIP1-dependent Necroptosis.

PubMed

LaRocca, Timothy J; Sosunov, Sergey A; Shakerley, Nicole L; Ten, Vadim S; Ratner, Adam J

2016-06-24

Necroptosis is a RIP1-dependent programmed cell death (PCD) pathway that is distinct from apoptosis. Downstream effector pathways of necroptosis include formation of advanced glycation end products (AGEs) and reactive oxygen species (ROS), both of which depend on glycolysis. This suggests that increased cellular glucose may prime necroptosis. Here we show that exposure to hyperglycemic levels of glucose enhances necroptosis in primary red blood cells (RBCs), Jurkat T cells, and U937 monocytes. Pharmacologic or siRNA inhibition of RIP1 prevented the enhanced death, confirming it as RIP1-dependent necroptosis. Hyperglycemic enhancement of necroptosis depends upon glycolysis with AGEs and ROS playing a role. Total levels of RIP1, RIP3, and mixed lineage kinase domain-like (MLKL) proteins were increased following treatment with high levels of glucose in Jurkat and U937 cells and was not due to transcriptional regulation. The observed increase in RIP1, RIP3, and MLKL protein levels suggests a potential positive feedback mechanism in nucleated cell types. Enhanced PCD due to hyperglycemia was specific to necroptosis as extrinsic apoptosis was inhibited by exposure to high levels of glucose. Hyperglycemia resulted in increased infarct size in a mouse model of brain hypoxia-ischemia injury. The increased infarct size was prevented by treatment with nec-1s, strongly suggesting that increased necroptosis accounts for exacerbation of this injury in conditions of hyperglycemia. This work reveals that hyperglycemia represents a condition in which cells are extraordinarily susceptible to necroptosis, that local glucose levels alter the balance of PCD pathways, and that clinically relevant outcomes may depend on glucose-mediated effects on PCD. © 2016 by The American Society for Biochemistry and Molecular Biology, Inc.

Study on the effect of reactive oxygen species-mediated oxidative stress on the activation of mitochondrial apoptosis and the tenderness of yak meat.

PubMed

Wang, Lin-Lin; Yu, Qun-Li; Han, Ling; Ma, Xiu-Li; Song, Ren-De; Zhao, Suo-Nan; Zhang, Wen-Hua

2018-04-01

This study investigated the effect of reactive oxygen species-mediated oxidative stress on activation of mitochondrial apoptosis and tenderness of yak meat during postmortem ageing. Oxidative stress degree, Ca 2+ levels, membrane permeability transition pore opening, mitochondrial membrane potential, apoptotic factors and the shear force were examined. Results showed that the ROS generated by H 2 O 2 significantly increased mitochondrial oxidative stress by decreasing the activities of superoxide dismutase, catalase and glutathione peroxidase, and increasing lipid peroxidation. Furthermore, oxidative stress enhanced Ca 2+ production and cytochrome c release, changed the levels of Bcl-2 family proteins and activated caspase-9 and -3 activities. Ultimately, oxidative stress increased the apoptosis rate and tenderness of yak meat. These observations confirmed that ROS-mediated oxidative stress participates in the activation of the apoptotic cascade reaction involving Ca 2+ and Bcl-2 family proteins. The results further suggested that ROS-mediated oxidative stress plays a significant role in meat tenderization through the mitochondrial apoptotic pathway. Copyright © 2017. Published by Elsevier Ltd.

Effect of oxidant stressors and phenolic antioxidants on the ochratoxigenic fungus Aspergillus carbonarius.

PubMed

Crespo-Sempere, Ana; Selma-Lázaro, Cristina; Palumbo, Jeffrey D; González-Candelas, Luis; Martínez-Culebras, Pedro V

2016-01-15

There are few studies dealing with the relationship between oxidative stress and ochratoxin A (OTA) biosynthesis. In this work, we analyzed the effect of the oxidant stressor menadione and the antioxidants 3,5-di-tert-butyl-4-hydroxytoluene (BHT), catechin, resveratrol and a polyphenolic extract on growth, generation of reactive oxygen species (ROS), OTA production and gene expression of antioxidant enzymes of Aspergillus carbonarius. Exposure to menadione concentrations higher than 20 µmol L(-1) led to increases in ROS and OTA levels and a decrease in growth rate. Exposure to 2.5-10 mmol L(-1) BHT also led to higher ROS and OTA levels, although growth rate was only affected above 5 mmol L(-1). Naturally occurring concentrations of catechin, resveratrol and polyphenolic extract barely affected growth rate, but they produced widely different effects on OTA production level depending on the antioxidant concentration used. In general, gene expression of antioxidant enzymes superoxide dismutase (SOD) and peroxiredoxin (PRX) was downregulated after exposure to oxidant and antioxidant concentrations that enhanced OTA production level. Aspergillus carbonarius responds to oxidative stress, increasing OTA production. Nevertheless, the use of naturally occurring concentrations of antioxidant phenolic compounds to reduce oxidative stress is not a valid approach by itself for OTA contamination control in grapes. © 2015 Society of Chemical Industry.

Salmonella Utilizes Zinc To Subvert Antimicrobial Host Defense of Macrophages via Modulation of NF-κB Signaling

PubMed Central

Wu, Aimin; Haschka, David; Heeke, Simon; Dichtl, Stefanie; Petzer, Verena; Seifert, Markus; Hilbe, Richard; Sopper, Sieghart; Talasz, Heribert; Bumann, Dirk; Lass-Flörl, Cornelia; Theurl, Igor; Zhang, Keying

2017-01-01

ABSTRACT Zinc sequestration by macrophages is considered a crucial host defense strategy against infection by the intracellular bacterium Salmonella enterica serovar Typhimurium. However, the underlying mechanisms remain elusive. In this study, we found that zinc favors pathogen survival within macrophages. Salmonella-hosting macrophages contained higher free zinc levels than did uninfected macrophages and cells that successfully eliminated bacteria, which was paralleled by the impaired production of reactive oxygen species (ROS) and reactive nitrogen species (RNS) in bacterium-harboring cells. A profound, zinc-mediated inhibition of NF-κB p65 transcriptional activity affecting the expression of the ROS- and RNS-forming enzymes phos47 and inducible nitric oxide synthase (iNOS) provided a mechanistic explanation for this phenomenon. Macrophages responded to infection by enhancing the expression of zinc-scavenging metallothioneins 1 and 2, whose genetic deletion caused increased free zinc levels, reduced ROS and RNS production, and increased the survival of Salmonella. Our data suggest that Salmonella invasion of macrophages results in a bacterium-driven increase in the intracellular zinc level, which weakens antimicrobial defense and the ability of macrophages to eradicate the pathogen. Thus, limitation of cytoplasmic zinc levels may help to control infection by intracellular bacteria. PMID:28874447

Oxidative Stress and Heart Failure in Altered Thyroid States

PubMed Central

Mishra, Pallavi; Samanta, Luna

2012-01-01

Increased or reduced action of thyroid hormone on certain molecular pathways in the heart and vasculature causes relevant cardiovascular derangements. It is well established that hyperthyroidism induces a hyperdynamic cardiovascular state, which is associated with a faster heart rate, enhanced left ventricular systolic and diastolic function whereas hypothyroidism is characterized by the opposite changes. Hyperthyroidism and hypothyroidism represent opposite clinical conditions, albeit not mirror images. Recent experimental and clinical studies have suggested the involvement of ROS tissue damage under altered thyroid status. Altered-thyroid state-linked changes in heart modify their susceptibility to oxidants and the extent of the oxidative damage they suffer following oxidative challenge. Chronic increase in the cellular levels of ROS can lead to a catastrophic cycle of DNA damage, mitochondrial dysfunction, further ROS generation and cellular injury. Thus, these cellular events might play an important role in the development and progression of myocardial remodeling and heart failure in altered thyroid states (hypo- and hyper-thyroidism). The present review aims at elucidating the various signaling pathways mediated via ROS and their modulation under altered thyroid state and the possibility of antioxidant therapy. PMID:22649319

ROS-mediated iron overload injures the hematopoiesis of bone marrow by damaging hematopoietic stem/progenitor cells in mice

PubMed Central

Chai, Xiao; Li, Deguan; Cao, Xiaoli; Zhang, Yuchen; Mu, Juan; Lu, Wenyi; Xiao, Xia; Li, Chengcheng; Meng, Juanxia; Chen, Jie; Li, Qing; Wang, Jishi; Meng, Aimin; Zhao, Mingfeng

2015-01-01

Iron overload, caused by hereditary hemochromatosis or repeated blood transfusions in some diseases, such as beta thalassemia, bone marrow failure and myelodysplastic syndrome, can significantly induce injured bone marrow (BM) function as well as parenchyma organ dysfunctions. However, the effect of iron overload and its mechanism remain elusive. In this study, we investigated the effects of iron overload on the hematopoietic stem and progenitor cells (HSPCs) from a mouse model. Our results showed that iron overload markedly decreased the ratio and clonogenic function of murine HSPCs by the elevation of reactive oxygen species (ROS). This finding is supported by the results of NAC or DFX treatment, which reduced ROS level by inhibiting NOX4 and p38MAPK and improved the long-term and multi-lineage engrafment of iron overload HSCs after transplantation. Therefore, all of these data demonstrate that iron overload injures the hematopoiesis of BM by enhancing ROS through NOX4 and p38MAPK. This will be helpful for the treatment of iron overload in patients with hematopoietic dysfunction. PMID:25970748

Vitamin C and sodium bicarbonate enhance the antioxidant ability of H9C2 cells and induce HSPs to relieve heat stress.

PubMed

Yin, Bin; Tang, Shu; Sun, Jiarui; Zhang, Xiaohui; Xu, Jiao; Di, Liangjiao; Li, Zhihong; Hu, Yurong; Bao, Endong

2018-02-13

Heat stress is exacerbated by global warming and affects human and animal health, leading to heart damage caused by imbalances in reactive oxygen species (ROS) and the antioxidant system, acid-base chemistry, electrolytes and respiratory alkalosis. Vitamin C scavenges excess ROS, and sodium bicarbonate maintains acid-base and electrolyte balance, and alleviates respiratory alkalosis. Herein, we explored the ability of vitamin C alone and in combination with equimolar sodium bicarbonate (Vitamin C-Na) to stimulate endogenous antioxidants and heat shock proteins (HSPs) to relieve heat stress in H9C2 cells. Control, vitamin C (20 μg/ml vitamin C for 16 h) and vitamin C-Na (20 μg/ml vitamin C-Na for 16 h) groups were heat-stressed for 1, 3 or 5 h. Granular and vacuolar degeneration, karyopyknosis and damage to nuclei and mitochondria were clearly reduced in treatment groups, as were apoptosis, lactate dehydrogenase activity and ROS and malondialdehyde levels, while superoxide dismutase activity was increased. Additionally, CRYAB, Hsp27, Hsp60 and Hsp70 mRNA levels were upregulated at 3 h (p < 0.01), and protein levels were increased for CRYAB at 0 h (p < 0.05) and 1 h (p < 0.01), and for Hsp70 at 3 and 5 h (p < 0.01). Thus, pre-treatment with vitamin C or vitamin C-Na might protect H9C2 cells against heat damage by enhancing the antioxidant ability and upregulating CRYAB and Hsp70.

Redox interventions to increase exercise performance

PubMed Central

2015-01-01

Abstract Skeletal muscle continually produces reactive oxygen species (ROS) and nitric oxide (NO) derivatives. Both oxidant cascades have complex effects on muscle contraction, metabolic function and tissue perfusion. Strenuous exercise increases oxidant production by muscle, limiting performance during endurance exercise tasks. Conversely, redox interventions that modulate ROS or NO activity have the potential to improve performance. Antioxidants have long been known to buffer ROS activity and lessen oxidative perturbations during exercise. The capacity to enhance human performance varies among antioxidant categories. Vitamins, provitamins and nutriceuticals often blunt oxidative changes at the biochemical level but do not enhance performance. In contrast, reduced thiol donors have been shown to delay fatigue or increase endurance under a variety of experimental conditions. Dietary nitrate supplementation has recently emerged as a second redox strategy for increasing endurance. Purified nitrate salts and nitrate‐rich foods, notably beetroot and beetroot juice, are reported to lessen the oxygen cost of exercise, increase efficiency, and enhance performance during endurance tasks. These findings are exciting but enigmatic since nitrate per se has little bioactivity and cannot be converted to NO by mammalian cells. Overall, the available data suggest exercise endurance can be augmented by redox‐active supplements, either reduced thiol donors or dietary nitrates. These findings have clear implications for athletes seeking a competitive edge. More importantly, interventions that increase endurance may benefit individuals whose physical activity is limited by illness, ageing, or frailty. PMID:26584644

Chloroplastic biosynthesis of melatonin and its involvement in protection of plants from salt stress

PubMed Central

Zheng, Xiaodong; Tan, Dun X.; Allan, Andrew C.; Zuo, Bixiao; Zhao, Yu; Reiter, Russel J.; Wang, Lin; Wang, Zhi; Guo, Yan; Zhou, Jingzhe; Shan, Dongqian; Li, Qingtian; Han, Zhenhai; Kong, Jin

2017-01-01

Within the chloroplasts reactive oxygen species (ROS) are generated during photosynthesis and stressful conditions. Excessive ROS damages chloroplasts and reduces photosynthesis if not properly detoxified. In this current study, we document that chloroplasts produce melatonin, a recently-discovered plant antioxidant molecule. When N-acetylserotonin, a substrate for melatonin synthesis, was fed to purified chloroplasts, they produced melatonin in a dose-response manner. To further confirm this function of chloroplasts, the terminal enzyme for melatonin synthesis, N-acetylserotonin-O-methyltransferase (ASMT), was cloned from apple rootstock, Malus zumi. The in vivo fluorescence observations and Western blots confirmed MzASMT9 was localized in the chloroplasts. A study of enzyme kinetics revealed that the Km and Vmax of the purified recombinant MzASMT9 protein for melatonin synthesis were 500 μM and 12 pmol/min·mg protein, respectively. Arabidopsis ectopically-expressing MzASMT9 possessed improved melatonin level. Importantly, the MzASMT9 gene was found to be upregulated by high light intensity and salt stress. Increased melatonin due to the highly-expressed MzASMT9 resulted in Arabidopsis lines with enhanced salt tolerance than wild type plants, as indicated by reduced ROS, lowered lipid peroxidation and enhanced photosynthesis. These findings have agricultural applications for the genetic enhancement of melatonin-enriched plants for increasing crop production under a variety of unfavorable environmental conditions. PMID:28145449

Autophagy is induced through the ROS-TP53-DRAM1 pathway in response to mitochondrial protein synthesis inhibition.

PubMed

Xie, Xiaolei; Le, Li; Fan, Yanxin; Lv, Lin; Zhang, Junjie

2012-07-01

Mitoribosome in mammalian cells is responsible for synthesis of 13 mtDNA-encoded proteins, which are integral parts of four mitochondrial respiratory chain complexes (I, III, IV and V). ERAL1 is a nuclear-encoded GTPase important for the formation of the 28S small mitoribosomal subunit. Here, we demonstrate that knockdown of ERAL1 by RNA interference inhibits mitochondrial protein synthesis and promotes reactive oxygen species (ROS) generation, leading to autophagic vacuolization in HeLa cells. Cells that lack ERAL1 expression showed a significant conversion of LC3-I to LC3-II and an enhanced accumulation of autophagic vacuoles carrying the LC3 marker, all of which were blocked by the autophagy inhibitor 3-MA as well as by the ROS scavenger NAC. Inhibition of mitochondrial protein synthesis either by ERAL1 siRNA or chloramphenicol (CAP), a specific inhibitor of mitoribosomes, induced autophagy in HTC-116 TP53 (+/+) cells, but not in HTC-116 TP53 (-/-) cells, indicating that tumor protein 53 (TP53) is essential for the autophagy induction. The ROS elevation resulting from mitochondrial protein synthesis inhibition induced TP53 expression at transcriptional levels by enhancing TP53 promoter activity, and increased TP53 protein stability by suppressing TP53 ubiquitination through MAPK14/p38 MAPK-mediated TP53 phosphorylation. Upregulation of TP53 and its downstream target gene DRAM1, but not CDKN1A/p21, was required for the autophagy induction in ERAL1 siRNA or CAP-treated cells. Altogether, these data indicate that autophagy is induced through the ROS-TP53-DRAM1 pathway in response to mitochondrial protein synthesis inhibition.

Curcumin abates hypoxia-induced oxidative stress based-ER stress-mediated cell death in mouse hippocampal cells (HT22) by controlling Prdx6 and NF-κB regulation

PubMed Central

Chhunchha, Bhavana; Fatma, Nigar; Kubo, Eri; Rai, Prerana; Singh, Sanjay P.

2013-01-01

Oxidative stress and endoplasmic reticulum (ER) stress are emerging as crucial events in the etiopathology of many neurodegenerative diseases. While the neuroprotective contributions of the dietary compound curcumin has been recognized, the molecular mechanisms underlying curcumin's neuroprotection under oxidative and ER stresses remains elusive. Herein, we show that curcumin protects HT22 from oxidative and ER stresses evoked by the hypoxia (1% O2 or CoCl2 treatment) by enhancing peroxiredoxin 6 (Prdx6) expression. Cells exposed to CoCl2 displayed reduced expression of Prdx6 with higher reactive oxygen species (ROS) expression and activation of NF-κB with IκB phosphorylation. When NF-κB activity was blocked by using SN50, an inhibitor of NF-κB, or cells treated with curcumin, the repression of Prdx6 expression was restored, suggesting the involvement of NF-κB in modulating Prdx6 expression. These cells were enriched with an accumulation of ER stress proteins, C/EBP homologous protein (CHOP), GRP/78, and calreticulin, and had activated states of caspases 12, 9, and 3. Reinforced expression of Prdx6 in HT22 cells by curcumin reestablished survival signaling by reducing propagation of ROS and blunting ER stress signaling. Intriguingly, knockdown of Prdx6 by antisense revealed that loss of Prdx6 contributed to cell death by sustaining enhanced levels of ER stress-responsive proapoptotic proteins, which was due to elevated ROS production, suggesting that Prdx6 deficiency is a cause of initiation of ROS-mediated ER stress-induced apoptosis. We propose that using curcumin to reinforce the naturally occurring Prdx6 expression and attenuate ROS-based ER stress and NF-κB-mediated aberrant signaling improves cell survival and may provide an avenue to treat and/or postpone diseases associated with ROS or ER stress. PMID:23364261

Impact of endophytic colonization patterns on Zamioculcas zamiifolia stress response and in regulating ROS, tryptophan and IAA levels under airborne formaldehyde and formaldehyde-contaminated soil conditions.

PubMed

Khaksar, Gholamreza; Treesubsuntorn, Chairat; Thiravetyan, Paitip

2017-05-01

Deeper understanding of plant-endophyte interactions under abiotic stress would provide new insights into phytoprotection and phytoremediation enhancement. Many studies have investigated the positive role of plant-endophyte interactions in providing protection to the plant against pollutant stress through auxin (indole-3-acetic acid (IAA)) production. However, little is known about the impact of endophytic colonization patterns on plant stress response in relation to reactive oxygen species (ROS) and IAA levels. Moreover, the possible effect of pollutant phase on plant stress response is poorly understood. Here, we elucidated the impact of endophytic colonization patterns on plant stress response under airborne formaldehyde compared to formaldehyde-contaminated soil. ROS, tryptophan and IAA levels in the roots and shoots of endophyte-inoculated and non-inoculated plants in the presence and absence of formaldehyde were measured. Strain-specific quantitative polymerase chain reaction (qPCR) was used to investigate dynamics of endophyte colonization. Under the initial exposure to airborne formaldehyde, non-inoculated plants accumulated more tryptophan in the shoots (compared to the roots) to synthesize IAA. However, endophyte-inoculated plants behaved differently as they synthesized and accumulated more tryptophan in the roots and, hence, higher levels of IAA accumulation and exudation within roots which might act as a signaling molecule to selectively recruit B. cereus ERBP. Under continuous airborne formaldehyde stress, higher levels of ROS accumulation in the shoots pushed the plant to synthesize more tryptophan and IAA in the shoots (compared to the roots). Higher levels of IAA in the shoots might act as the potent driving force to relocalize B. cereus ERBP from roots to the shoots. In contrast, under formaldehyde-contaminated soil, B. cereus ERBP colonized root tissues without moving to the shoots since there was a sharp increase in ROS, tryptophan and IAA levels of the roots without any significant increase in the shoots. Pollutant phase affected endophytic colonization patterns and plant stress responses differently. Copyright © 2017 Elsevier Masson SAS. All rights reserved.

Reactive oxygen species-mediated breast cell carcinogenesis enhanced by multiple carcinogens and intervened by dietary ergosterol and mimosine.

PubMed

Pluchino, Lenora Ann; Liu, Amethyst Kar-Yin; Wang, Hwa-Chain Robert

2015-03-01

Most breast cancers occur sporadically due to long-term exposure to low-dose carcinogens in the diet and the environment. Specifically, smoke, polluted air, and high-temperature cooked meats comprise multiple carcinogens, such as 4-(methylnitrosamino)-1-(3-pyridyl)-1-butanone (NNK), benzo[α]pyrene (B[α]P), and 2-amino-1-methyl-6-phenylimidazo[4,5-b]pyridine (PhIP). We sought to determine if these carcinogens act together to induce breast cell carcinogenesis, and if so, whether noncytotoxic dietary agents could intervene. We demonstrated that coexposure to physiologically achievable doses of NNK, B[α]P, and PhIP (NBP) holistically enhanced initiation and progression of breast cell carcinogenesis. Reactive oxygen species (ROS) and activation of the ERK pathway were transiently induced by NBP in each exposure, and cross talk between reinforced ROS elevation and ERK activation played an essential role in increased DNA oxidation and damage. After cumulative exposures to NBP, this cross talk contributed to enhanced initiation of cellular carcinogenesis and led to enhanced acquisition of cancer-associated properties. Using NBP-induced transient changes, such as ROS elevation and ERK pathway activation, and cancer-associated properties as targeted endpoints, we revealed, for the first time, that two less-studied dietary compounds, ergosterol and mimosine, at physiologically achievable noncytotoxic levels, were highly effective in intervention of NBP-induced cellular carcinogenesis. Combined ergosterol and mimosine were more effective than individual agents in blocking NBP-induced transient endpoints, including ROS-mediated DNA oxidation, which accounted for their preventive ability to suppress progression of NBP-induced cellular carcinogenesis. Thus, dietary components, such as mushrooms containing ergosterol and legumes containing mimosine, should be considered for affordable prevention of sporadic breast cancer associated with long-term exposure to environmental and dietary carcinogens. Copyright © 2014 Elsevier Inc. All rights reserved.

Reactive oxygen species (ROS) and the heat stress response of Daphnia pulex: ROS-mediated activation of hypoxia-inducible factor 1 (HIF-1) and heat shock factor 1 (HSF-1) and the clustered expression of stress genes.

PubMed

Klumpen, Eva; Hoffschröer, Nadine; Zeis, Bettina; Gigengack, Ulrike; Dohmen, Elias; Paul, Rüdiger J

2017-01-01

Heat stress in ectotherms involves direct (e.g. protein damage) and/or indirect effects (temperature-induced hypoxia and ROS formation), which cause activation of the transcription factors (TF) heat shock factor 1 (HSF-1) and/or hypoxia-inducible factor 1 (HIF-1). The present study focused on the links between stress (ROS) signals, nuclear (n) and cytoplasmic (c) HSF-1/HIF-1 levels, and stress gene expression on mRNA and protein levels (e.g. heat-shock protein 90, HSP90) upon acute heat and ROS (H 2 O 2 ) stress. Acute heat stress (30°C) evoked fluctuations in ROS level. Different feeding regimens, which affected the glutathione (GSH) level, allowed altering the frequency of ROS fluctuations. Other data showed fluctuation frequency to depend also on ROS production rate. The heat-induced slow or fast ROS fluctuations (at high or low GSH levels) evoked slow or fast fluctuations in the levels of nHIF-1α, nHSF-1 and gene products (mRNAs and protein), albeit after different time delays. Time delays to ROS fluctuations were, for example,shorter for nHIF-1α than for nHSF-1 fluctuations, and nHIF-1α fluctuations preceded and nHSF-1 fluctuations followed fluctuations in HSP90 mRNA level. Cytoplasmic TF levels either changed little (cHIF-1α) or showed a steady increase (cHSF-1). Applying acute H 2 O 2 stress (at 20°C) revealed effects on nHIF-1α and mRNA levels, but no significant effects on nHSF-1 level. Transcriptome data additionally showed coordinated fluctuations of mRNA levels upon acute heat stress, involving mRNAs for HSPs and other stress proteins, with all corresponding genes carrying DNA binding motifs for HIF-1 and HSF-1. This study provided evidence for promoting effects of ROS and HIF-1 on early haemoglobin, HIF-1α and HSP90 mRNA expressions upon heat or ROS stress. The increasing cHSF-1 level likely affected nHSF-1 level and later HSP90 mRNA expression. Heat stress evoked ROS fluctuations, with this stress signal forwarded via nHIF-1 and nHSF-1 fluctuations to stress gene expression. The frequency of ROS fluctuations seemed to integrate information about ROS productionrate and GSH antioxidant buffer capacity, resulting in stress protein expression of different speed. Results of this study suggest ROS as early (pre-damage) and protein defects as later (post-damage) stress signals to trigger heat stress responses. © 2016 Société Française des Microscopies and Société de Biologie Cellulaire de France. Published by John Wiley & Sons Ltd.

Ascorbic acid alters cell fate commitment of human neural progenitors in a WNT/β-catenin/ROS signaling dependent manner.

PubMed

Rharass, Tareck; Lantow, Margareta; Gbankoto, Adam; Weiss, Dieter G; Panáková, Daniela; Lucas, Stéphanie

2017-10-16

Improving the neuronal yield from in vitro cultivated neural progenitor cells (NPCs) is an essential challenge in transplantation therapy in neurological disorders. In this regard, Ascorbic acid (AA) is widely used to expand neurogenesis from NPCs in cultures although the mechanisms of its action remain unclear. Neurogenesis from NPCs is regulated by the redox-sensitive WNT/β-catenin signaling pathway. We therefore aimed to investigate how AA interacts with this pathway and potentiates neurogenesis. Effects of 200 μM AA were compared with the pro-neurogenic reagent and WNT/β-catenin signaling agonist lithium chloride (LiCl), and molecules with antioxidant activities i.e. N-acetyl-L-cysteine (NAC) and ruthenium red (RuR), in differentiating neural progenitor ReNcell VM cells. Cells were supplemented with reagents for two periods of treatment: a full period encompassing the whole differentiation process versus an early short period that is restricted to the cell fate commitment stage. Intracellular redox balance and reactive oxygen species (ROS) metabolism were examined by flow cytometry using redox and ROS sensors. Confocal microscopy was performed to assess cell viability, neuronal yield, and levels of two proteins: Nucleoredoxin (NXN) and the WNT/β-catenin signaling component Dishevelled 2 (DVL2). TUBB3 and MYC gene responses were evaluated by quantitative real-time PCR. DVL2-NXN complex dissociation was measured by fluorescence resonance energy transfer (FRET). In contrast to NAC which predictably exhibited an antioxidant effect, AA treatment enhanced ROS metabolism with no cytotoxic induction. Both drugs altered ROS levels only at the early stage of the differentiation as no changes were held beyond the neuronal fate commitment stage. FRET studies showed that AA treatment accelerated the redox-dependent release of the initial pool of DVL2 from its sequestration by NXN, while RuR treatment hampered the dissociation of the two proteins. Accordingly, AA increased WNT/β-catenin signaling output i.e. MYC mRNA level, whereas RuR attenuated it. Moreover, AA improved neurogenesis as much as LiCl as both TUBB3-positive cell yield and TUBB3 mRNA level increased, while NAC or RuR attenuated neurogenesis. Markedly, the neurogenesis outputs between the short and the full treatment with either NAC or AA were found unchanged, supporting our model that neuronal yield is altered by events taking place at the early phase of differentiation. Our findings demonstrate that AA treatment elevates ROS metabolism in a non-lethal manner prior to the NPCs commitment to their neuronal fate. Such effect stimulates the redox-sensitive DVL2 activation and WNT/β-catenin signaling response that would enhance the ensuing neuronal cell differentiation.

Reactive oxygen species-based measurement of the dependence of the Coulomb nanoradiator effect on proton energy and atomic Z value.

PubMed

Seo, Seung-Jun; Jeon, Jae-Kun; Han, Sung-Mi; Kim, Jong-Ki

2017-11-01

The Coulomb nanoradiator (CNR) effect produces the dose enhancement effects from high-Z nanoparticles under irradiation with a high-energy ion beam. To gain insight into the radiation dose and biological significance of the CNR effect, the enhancement of reactive oxygen species (ROS) production from iron oxide or gold NPs (IONs or AuNPs, respectively) in water was investigated using traversing proton beams. The dependence of nanoradiator-enhanced ROS production on the atomic Z value and proton energy was investigated. Two biologically important ROS species were measured using fluorescent probes specific to •OH or [Formula: see text] in a series of water phantoms containing either AuNPs or IONs under irradiation with a 45- or 100-MeV proton beam. The enhanced generation of hydroxyl radicals (•OH) and superoxide anions ([Formula: see text]) was determined to be caused by the dependence on the NP concentration and proton energy. The proton-induced Au or iron oxide nanoradiators exhibited different ROS enhancement rates depending on the proton energy, suggesting that the CNR radiation varied. The curve of the superoxide anion production from the Au-nanoradiator showed strong non-linearity, unlike the linear behavior observed for hydroxyl radical production and the X-ray photoelectric nanoradiator. In addition, the 45-MeV proton-induced Au nanoradiator exhibited an ROS enhancement ratio of 8.54/1.50 ([Formula: see text] / •OH), similar to that of the 100-KeV X-ray photoelectric Au nanoradiator (7.68/1.46). The ROS-based detection of the CNR effect revealed its dependence on the proton beam energy, dose and atomic Z value and provided insight into the low-linear energy transfer (LET) CNR radiation, suggesting that these factors may influence the therapeutic efficacy via chemical reactivities, transport behaviors, and intracellular oxidative stress.

CUL4B impedes stress-induced cellular senescence by dampening a p53-reactive oxygen species positive feedback loop.

PubMed

Wei, Zhao; Guo, Haiyang; Liu, Zhaojian; Zhang, Xiyu; Liu, Qiao; Qian, Yanyan; Gong, Yaoqin; Shao, Changshun

2015-02-01

Tumor suppressor p53 is known to regulate the level of intracellular reactive oxygen species (ROS). It can either alleviate oxidative stress under physiological and mildly stressed conditions or exacerbate oxidative stress under highly stressed conditions. We here report that a p53-ROS positive feedback loop drives a senescence program in normal human fibroblasts (NHFs) and this senescence-driving loop is negatively regulated by CUL4B. CUL4B, which can assemble various ubiquitin E3 ligases, was found to be downregulated in stress-induced senescent cells, but not in replicative senescent cells. We observed that p53-dependent ROS production was significantly augmented and stress-induced senescence was greatly enhanced when CUL4B was absent or depleted. Ectopic expression of CUL4B, on the other hand, blunted p53 activation, reduced ROS production, and attenuated cellular senescence in cells treated with H2O2. CUL4B was shown to promote p53 ubiquitination and proteosomal degradation in NHFs exposed to oxidative stress, thus dampening the p53-dependent cellular senescence. Together, our results established a critical role of CUL4B in negatively regulating the p53-ROS positive feedback loop that drives cellular senescence. Copyright © 2014 Elsevier Inc. All rights reserved.

ACE inhibition with captopril retards the development of signs of neurodegeneration in an animal model of Alzheimer's disease.

PubMed

AbdAlla, Said; Langer, Andreas; Fu, Xuebin; Quitterer, Ursula

2013-08-16

Increased generation of reactive oxygen species (ROS) is a significant pathological feature in the brains of patients with Alzheimer's disease (AD). Experimental evidence indicates that inhibition of brain ROS could be beneficial in slowing the neurodegenerative process triggered by amyloid-beta (Abeta) aggregates. The angiotensin II AT1 receptor is a significant source of brain ROS, and AD patients have an increased brain angiotensin-converting enzyme (ACE) level, which could account for an excessive angiotensin-dependent AT1-induced ROS generation. Therefore, we analyzed the impact of ACE inhibition on signs of neurodegeneration of aged Tg2576 mice as a transgenic animal model of AD. Whole genome microarray gene expression profiling and biochemical analyses demonstrated that the centrally active ACE inhibitor captopril normalized the excessive hippocampal ACE activity of AD mice. Concomitantly, the development of signs of neurodegeneration was retarded by six months of captopril treatment. The neuroprotective profile triggered by captopril was accompanied by reduced amyloidogenic processing of the amyloid precursor protein (APP), and decreased hippocampal ROS, which is known to enhance Abeta generation by increased activation of beta- and gamma-secretases. Taken together, our data present strong evidence that ACE inhibition with a widely used cardiovascular drug could interfere with Abeta-dependent neurodegeneration.

ACE Inhibition with Captopril Retards the Development of Signs of Neurodegeneration in an Animal Model of Alzheimer’s Disease

PubMed Central

AbdAlla, Said; Langer, Andreas; Fu, Xuebin; Quitterer, Ursula

2013-01-01

Increased generation of reactive oxygen species (ROS) is a significant pathological feature in the brains of patients with Alzheimer’s disease (AD). Experimental evidence indicates that inhibition of brain ROS could be beneficial in slowing the neurodegenerative process triggered by amyloid-beta (Abeta) aggregates. The angiotensin II AT1 receptor is a significant source of brain ROS, and AD patients have an increased brain angiotensin-converting enzyme (ACE) level, which could account for an excessive angiotensin-dependent AT1-induced ROS generation. Therefore, we analyzed the impact of ACE inhibition on signs of neurodegeneration of aged Tg2576 mice as a transgenic animal model of AD. Whole genome microarray gene expression profiling and biochemical analyses demonstrated that the centrally active ACE inhibitor captopril normalized the excessive hippocampal ACE activity of AD mice. Concomitantly, the development of signs of neurodegeneration was retarded by six months of captopril treatment. The neuroprotective profile triggered by captopril was accompanied by reduced amyloidogenic processing of the amyloid precursor protein (APP), and decreased hippocampal ROS, which is known to enhance Abeta generation by increased activation of beta- and gamma-secretases. Taken together, our data present strong evidence that ACE inhibition with a widely used cardiovascular drug could interfere with Abeta-dependent neurodegeneration. PMID:23959119

N-n-butyl haloperidol iodide ameliorates hypoxia/reoxygenation injury through modulating the LKB1/AMPK/ROS pathway in cardiac microvascular endothelial cells.

PubMed

Lu, Binger; Wang, Bin; Zhong, Shuping; Zhang, Yanmei; Gao, Fenfei; Chen, Yicun; Zheng, Fuchun; Shi, Ganggang

2016-06-07

Endothelial cells are highly sensitive to hypoxia and contribute to myocardial ischemia/reperfusion injury. We have reported that N-n-butyl haloperidol iodide (F2) can attenuate hypoxia/reoxygenation (H/R) injury in cardiac microvascular endothelial cells (CMECs). However, the molecular mechanisms remain unclear. Neonatal rat CMECs were isolated and subjected to H/R. Pretreatment of F2 leads to a reduction in H/R injury, as evidenced by increased cell viability, decreased lactate dehydrogenase (LDH) leakage and apoptosis, together with enhanced AMP-activated protein kinase (AMPK) and liver kinase B1 (LKB1) phosphorylation in H/R ECs. Blockade of AMPK with compound C reversed F2-induced inhibition of H/R injury, as evidenced by decreased cell viability, increased LDH release and apoptosis. Moreover, compound C also blocked the ability of F2 to reduce H/R-induced reactive oxygen species (ROS) generation. Supplementation with the ROS scavenger N-acetyl-L-cysteine (NAC) reduced ROS levels, increased cell survival rate, and decreased both LDH release and apoptosis after H/R. In conclusion, our data indicate that F2 may mitigate H/R injury by stimulating LKB1/AMPK signaling pathway and subsequent suppression of ROS production in CMECs.

Prostaglandin E2 promotes proliferation of skeletal muscle myoblasts via EP4 receptor activation.

PubMed

Mo, Chenglin; Zhao, Ruonan; Vallejo, Julian; Igwe, Orisa; Bonewald, Lynda; Wetmore, Lori; Brotto, Marco

2015-01-01

We recently demonstrated that conditioned media (CM) from osteocytes enhances myogenic differentiation of myoblasts, suggesting that signaling from bone may be important for skeletal muscle myogenesis. The effect of CM was closely mimicked by prostaglandin E2 (PGE2), a bioactive lipid mediator in various physiological or pathological conditions. PGE2 is secreted at high levels by osteocytes and such secretion is further enhanced under loading conditions. Although four types of receptors, EP1 to EP4, mediate PGE2 signaling, it is unknown whether these receptors play a role in myogenesis. Therefore, in this study, the expression of EPs in mouse primary myoblasts was characterized, followed by examination of their roles in myoblast proliferation by treating myoblasts with PGE2 or specific agonists. All four PGE2 receptor mRNAs were detectable by quantitative real-time PCR (qPCR), but only PGE2 and EP4 agonist CAY 10598 significantly enhance myoblast proliferation. EP1/EP3 agonist 17-phenyl trinor PGE2 (17-PT PGE2) and EP2 agonist butaprost did not have any significant effects. Moreover, treatment with EP4 antagonist L161,982 dose-dependently inhibited myoblast proliferation. These results were confirmed by cell cycle analysis and the gene expression of cell cycle regulators. Concomitant with the inhibition of myoblast proliferation, treatment with L161,982 significantly increased intracellular reactive oxygen species (ROS) levels. Cotreatment with antioxidant N-acetyl cysteine (NAC) or sodium ascorbate (SA) successfully reversed the inhibition of myoblast proliferation and ROS overproduction caused by L161,982. Therefore, PGE2 signaling via the EP4 receptor regulates myogenesis by promoting myoblast proliferation and blocking this receptor results in increased ROS production in myoblasts.

Prostaglandin E2 promotes proliferation of skeletal muscle myoblasts via EP4 receptor activation

PubMed Central

Mo, Chenglin; Zhao, Ruonan; Vallejo, Julian; Igwe, Orisa; Bonewald, Lynda; Wetmore, Lori; Brotto, Marco

2015-01-01

We recently demonstrated that conditioned media (CM) from osteocytes enhances myogenic differentiation of myoblasts, suggesting that signaling from bone may be important for skeletal muscle myogenesis. The effect of CM was closely mimicked by prostaglandin E2 (PGE2), a bioactive lipid mediator in various physiological or pathological conditions. PGE2 is secreted at high levels by osteocytes and such secretion is further enhanced under loading conditions. Although four types of receptors, EP1 to EP4, mediate PGE2 signaling, it is unknown whether these receptors play a role in myogenesis. Therefore, in this study, the expression of EPs in mouse primary myoblasts was characterized, followed by examination of their roles in myoblast proliferation by treating myoblasts with PGE2 or specific agonists. All four PGE2 receptor mRNAs were detectable by quantitative real-time PCR (qPCR), but only PGE2 and EP4 agonist CAY 10598 significantly enhance myoblast proliferation. EP1/EP3 agonist 17-phenyl trinor PGE2 (17-PT PGE2) and EP2 agonist butaprost did not have any significant effects. Moreover, treatment with EP4 antagonist L161,982 dose-dependently inhibited myoblast proliferation. These results were confirmed by cell cycle analysis and the gene expression of cell cycle regulators. Concomitant with the inhibition of myoblast proliferation, treatment with L161,982 significantly increased intracellular reactive oxygen species (ROS) levels. Cotreatment with antioxidant N-acetyl cysteine (NAC) or sodium ascorbate (SA) successfully reversed the inhibition of myoblast proliferation and ROS overproduction caused by L161,982. Therefore, PGE2 signaling via the EP4 receptor regulates myogenesis by promoting myoblast proliferation and blocking this receptor results in increased ROS production in myoblasts. PMID:25785867

Impact of solar UV radiation on toxicity of ZnO nanoparticles through photocatalytic reactive oxygen species (ROS) generation and photo-induced dissolution.

PubMed

Ma, Hongbo; Wallis, Lindsay K; Diamond, Steve; Li, Shibin; Canas-Carrell, Jaclyn; Parra, Amanda

2014-10-01

The present study investigated the impact of solar UV radiation on ZnO nanoparticle toxicity through photocatalytic ROS generation and photo-induced dissolution. Toxicity of ZnO nanoparticles to Daphnia magna was examined under laboratory light versus simulated solar UV radiation (SSR). Photocatalytic ROS generation and particle dissolution were measured on a time-course basis. Two toxicity mitigation assays using CaCl2 and N-acetylcysteine were performed to differentiate the relative importance of these two modes of action. Enhanced ZnO nanoparticle toxicity under SSR was in parallel with photocatalytic ROS generation and enhanced particle dissolution. Toxicity mitigation by CaCl2 to a less extent under SSR than under lab light demonstrates the role of ROS generation in ZnO toxicity. Toxicity mitigation by N-acetylcysteine under both irradiation conditions confirms the role of particle dissolution and ROS generation. These findings demonstrate the importance of considering environmental solar UV radiation when assessing ZnO nanoparticle toxicity and risk in aquatic systems. Copyright © 2014 Elsevier Ltd. All rights reserved.

The anthocyanin cyanidin-3-O-β-glucoside, a flavonoid, increases hepatic glutathione synthesis and protects hepatocytes against reactive oxygen species during hyperglycemia: Involvement of a cAMP-PKA-dependent signaling pathway.

PubMed

Zhu, Wei; Jia, Qianju; Wang, Yun; Zhang, Yuhua; Xia, Min

2012-01-15

Enhanced oxidative stress due to high glucose contributes to pathological changes in diabetes-related liver complications. Reducing oxidative stress may alleviate these pathogenic processes. Anthocyanin, a natural antioxidant, has been reported to reduce intracellular reactive oxygen species (ROS) levels but the mechanism of this reduction is not fully understood. The glutathione (GSH) antioxidant system is critical for counteracting oxidative stress-induced intracellular injury. In this study, we evaluated the mechanism of the anthocyanin-mediated regulation of GSH synthesis and reduction in intracellular ROS levels. We observed that treatment of human HepG2 cells with the anthocyanin C3G significantly reduced ROS levels induced by high glucose. C3G incubation increased glutamate-cysteine ligase expression, which in turn mediated the reduction in ROS levels. However, the upregulation of glutamate-cysteine ligase catalytic subunit (Gclc) expression by C3G occurred independent of the Nrf1/2 transcription factors. Notably, the cAMP-response element binding protein (CREB) was identified as the target transcription factor involved in the C3G-mediated upregulation of Gclc expression. C3G increased phosphorylation of CREB through protein kinase A (PKA) activation, which induced a CREB-mediated upregulation of Gclc transcription. In vivo, treatment with C3G increased the GSH synthesis in the liver of diabetic db/db mice through PKA-CREB-dependent induction of Gclc expression. Finally, oxidative stress determined by lipid peroxidation, neutrophil infiltration, and hepatic steatosis was attenuated in C3G-treated db/db mice. Our results demonstrate that the anthocyanin C3G has an effect of activating GSH synthesis through a novel antioxidant defense mechanism against excessive ROS production, contributing to the prevention of hyperglycemia-induced hepatic oxidative damage. Crown Copyright © 2011. Published by Elsevier Inc. All rights reserved.

High level of reactive oxygen species impaired mesenchymal stem cell migration via overpolymerization of F-actin cytoskeleton in systemic lupus erythematosus.

PubMed

Shi, D; Li, X; Chen, H; Che, N; Zhou, S; Lu, Z; Shi, S; Sun, L

2014-12-01

Some lines of evidence have demonstrated abnormalities of bone marrow mesenchymal stem cells (MSCs) in systemic lupus erythematosus (SLE) patients, characterized by defective phenotype of MSCs and slower growth with enhanced apoptosis and senescence. However, whether SLE MSCs demonstrate aberrant migration capacity or abnormalities in cytoskeleton are issues that remain poorly understood. In this study, we found that MSCs from SLE patients did show impairment in migration capacity as well as abnormalities in F-actin cytoskeleton, accompanied by a high level of intracellular reactive oxygen species (ROS). When normal MSCs were treated in vitro with H2O2, which increases intracellular ROS level as an oxidant, both reorganization of F-actin cytoskeleton and impairment of migration capability were observed. On the other hand, treatment with N-acetylcysteine (NAC), as an exogenous antioxidant, made F-actin more orderly and increased migration ratio in SLE MSCs. In addition, oral administration of NAC markedly reduced serum autoantibody levels and ameliorated lupus nephritis (LN) in MRL/lpr mice, partially reversing the abnormalities of MSCs. These results indicate that overpolymerization of F-actin cytoskeleton, which may be associated with high levels of ROS, causes impairment in the migration capacity of SLE MSCs and that oral administration of NAC may have potential therapeutic effects on MRL/lpr mice. Copyright © 2014 Elsevier Masson SAS. All rights reserved.

Endoplasmic reticulum-derived reactive oxygen species (ROS) is involved in toxicity of cell wall stress to Candida albicans.

PubMed

Yu, Qilin; Zhang, Bing; Li, Jianrong; Zhang, Biao; Wang, Honggang; Li, Mingchun

2016-10-01

The cell wall is an important cell structure in both fungi and bacteria, and hence becomes a common antimicrobial target. The cell wall-perturbing agents disrupt synthesis and function of cell wall components, leading to cell wall stress and consequent cell death. However, little is known about the detailed mechanisms by which cell wall stress renders fungal cell death. In this study, we found that ROS scavengers drastically attenuated the antifungal effect of cell wall-perturbing agents to the model fungal pathogen Candida albicans, and these agents caused remarkable ROS accumulation and activation of oxidative stress response (OSR) in this fungus. Interestingly, cell wall stress did not cause mitochondrial dysfunction and elevation of mitochondrial superoxide levels. Furthermore, the iron chelator 2,2'-bipyridyl (BIP) and the hydroxyl radical scavengers could not attenuate cell wall stress-caused growth inhibition and ROS accumulation. However, cell wall stress up-regulated expression of unfold protein response (UPR) genes, enhanced protein secretion and promoted protein folding-related oxidation of Ero1, an important source of ROS production. These results indicated that oxidation of Ero1 in the endoplasmic reticulum (ER), rather than mitochondrial electron transport and Fenton reaction, contributed to cell wall stress-related ROS accumulation and consequent growth inhibition. Our findings uncover a novel link between cell wall integrity (CWI), ER function and ROS production in fungal cells, and shed novel light on development of strategies promoting the antifungal efficacy of cell wall-perturbing agents against fungal infections. Copyright © 2016 Elsevier Inc. All rights reserved.

Rosmarinic acid induces rabbit articular chondrocyte differentiation by decreases matrix metalloproteinase-13 and inflammation by upregulating cyclooxygenase-2 expression.

PubMed

Eo, Seong-Hui; Kim, Song Ja

2017-09-18

Matrix metalloproteinases (MMPs) are known to play an important role in the degradation of the extracellular matrix and the pathological progression of osteoarthritis (OA). The natural polyphenolic compound rosmarinic acid (Ros. A) has been shown to suppress the inhibitory activity of matrix metalloproteinases (MMPs). However, the effects of Ros. A on OA have not been investigated. In the current study, primary articular chondrocytes were cultured from rabbit articular cartilage and treated with Ros. A. Phenotypic characterization was performed by western blotting to assess specific markers, prostaglandin E 2 (PGE 2 ) assays, and alcian blue staining to measure sulfated-proteoglycan production. We report that in rabbit articular chondrocytes, Ros. A increased type II collagen, sulfated-proteoglycan, cyclooxygenase-2 (COX-2), and PGE 2 production in a dose- and time-dependent manner. Furthermore, Ros. A suppressed the expression of MMP-13. In addition, treatment with Ros A activated extracellular signal-regulated kinase (ERK)-1/2 and p38 kinase signaling pathways. Inhibition of MMP-13 enhanced Ros. A-induced type II collagen expression and sulfated-proteoglycan synthesis but COX-2 and PGE 2 production were unchanged. Ros. A-mediated up-regulation of ERK phosphorylation was abolished by the MEK inhibitor, PD98059, which prevented induction of the associated inflammatory response. Inhibition of p38 kinase with SB203580 enhanced the increase in type II collagen expression via Ros. A-mediated down-regulation of MMP-13. Results suggest that ERK-1/2 regulates Ros. A-induced inflammation and that p38 regulates differentiation by inhibiting MMP-13 in rabbit articular chondrocytes.

Neuroprotective Effects of Reactive Oxygen Species Mediated by BDNF-Independent Activation of TrkB

PubMed Central

Huang, Yang Zhong; McNamara, James O.

2012-01-01

Reactive oxygen species (ROS) have diverse biological consequences in the mammalian CNS, but the molecular targets mediating these pleiotropic effects are incompletely understood. Like ROS, the neurotrophin receptor, TrkB receptor tyrosine kinase, has diverse effects in the developing and mature mammalian brain. Our discovery that zinc can transactivate TrkB, together with the finding that ROS can trigger zinc release from cytosolic zinc binding proteins, led us to hypothesize that ROS can transactivate TrkB in CNS neurons by a zinc-dependent mechanism. We found that both exogenous H2O2 and endogenous ROS activate TrkB signaling by a Src family kinase-dependent but brain-derived neurotrophic factor-independent mechanism in cultured rat cortical neurons. Exogenous H2O2 enhances cytosolic zinc content in a metallothionein-3 (MT-3)-requiring manner. Both exogenous H2O2 and endogenous ROS mediated transactivation of TrkB requires intracellular zinc and MT-3. The ROS-triggered transactivation of TrkB exerts neuroprotective effects, because inhibition of TrkB kinase activity or uncoupling Shc signaling from TrkB exacerbates neuronal cell death induced by H2O2. Thus, we propose a molecular signaling event whereby ROS induce release of zinc from cytosolic MT-3, the increased cytosolic zinc transactivates TrkB, and the enhanced Shc signaling downstream from TrkB promotes prosurvival effects. We suggest that such neuroprotective effects mediated by ROS are operative in diverse acute and chronic neurological disorders. PMID:23115189

A ROS-responsive polymeric micelle with a π-conjugated thioketal moiety for enhanced drug loading and efficient drug delivery.

PubMed

Sun, Changzhen; Liang, Yan; Hao, Na; Xu, Long; Cheng, Furong; Su, Ting; Cao, Jun; Gao, Wenxia; Pu, Yuji; He, Bin

2017-11-07

As the implications of reactive oxygen species (ROS) are elucidated in many diseases, ROS-responsive nanoparticles are attracting great interest from researchers. In this work, a ROS sensitive thioketal (TK) moiety with a π-conjugated structure was introduced into biodegradable methoxy poly(ethylene glycol)-thioketal-poly(ε-caprolactone)mPEG-TK-PCL micelles as a linker, which was designed to speed up the drug release and thus enhance the therapeutic efficacy. The micelle showed a high drug loading content of 12.8% and excellent stability under physiological conditions because of the evocation of π-π stacking and hydrophobic interactions with the anticancer drug doxorubicin (DOX). The polymeric micelle presented a better drug carrier capacity and higher in vitro anticancer efficacy towards cancer cells. The in vivo study showed that DOX-loaded mPEG-TK-PCL micelles displayed lower toxicity towards normal cells and remarkably enhanced antitumor efficacy. This research provides a way to design potential drug carriers for efficient cancer chemotherapy.

Activation of antioxidant pathways in ras-mediated oncogenic transformation of human surface ovarian epithelial cells revealed by functional proteomics and mass spectrometry.

PubMed

Young, Travis W; Mei, Fang C; Yang, Gong; Thompson-Lanza, Jennifer A; Liu, Jinsong; Cheng, Xiaodong

2004-07-01

Cellular transformation is a complex process involving genetic alterations associated with multiple signaling pathways. Development of a transformation model using defined genetic elements has provided an opportunity to elucidate the role of oncogenes and tumor suppressor genes in the initiation and development of ovarian cancer. To study the cellular and molecular mechanisms of Ras-mediated oncogenic transformation of ovarian epithelial cells, we used a proteomic approach involving two-dimensional electrophoresis and mass spectrometry to profile two ovarian epithelial cell lines, one immortalized with SV40 T/t antigens and the human catalytic subunit of telomerase and the other transformed with an additional oncogenic ras(V12) allele. Of approximately 2200 observed protein spots, we have identified >30 protein targets that showed significant changes between the immortalized and transformed cell lines using peptide mass fingerprinting. Among these identified targets, one most notable group of proteins altered significantly consists of enzymes involved in cellular redox balance. Detailed analysis of these protein targets suggests that activation of Ras-signaling pathways increases the threshold of reactive oxidative species (ROS) tolerance by up-regulating the overall antioxidant capacity of cells, especially in mitochondria. This enhanced antioxidant capacity protects the transformed cells from high levels of ROS associated with the uncontrolled growth potential of tumor cells. It is conceivable that an enhanced antioxidation capability may constitute a common mechanism for tumor cells to evade apoptosis induced by oxidative stresses at high ROS levels.

Involvement of histone H3 phosphorylation via the activation of p38 MAPK pathway and intracellular redox status in cytotoxicity of HL-60 cells induced by Vitex agnus-castus fruit extract.

PubMed

Kikuchi, Hidetomo; Yuan, Bo; Yuhara, Eisuke; Imai, Masahiko; Furutani, Ryota; Fukushima, Shin; Hazama, Shingo; Hirobe, Chieko; Ohyama, Kunio; Takagi, Norio; Toyoda, Hiroo

2014-08-01

We have demonstrated that an extract from the ripe fruit of Vitex angus-castus (Vitex), might be a promising anticancer candidate. In order to further provide a molecular rationale for clinical development in anticancer therapy, a detailed mechanism underlying the efficacy of Vitex against HL-60 cells was investigated. Vitex induced a dose- and time-dependent decrease in cell viability associated with induction of apoptosis and G(2)/M cell cycle arrest, both of which were suppressed by the addition of SB203580, an inhibitor for p38 MAPK. Furthermore, SB203580 significantly suppressed Vitex-induced phosphorylation of histone H3, a downstream molecule of p38 MAPK known to be involved in apoptosis induction in tumor cells. Notably, Vitex induced upregulation of intracellular ATP, known to bind its binding pocket inside activated p38 MAPK and to be required for the activation of p38 MAPK pathway. These results, thus, suggest that upregulation of intracellular ATP and phosphorylation of histone H3 are closely associated with the activation of p38 MAPK pathway, consequently contributing to Vitex-mediated cytotoxicity. Intriguingly, a significant decrease of intracellular ROS levels and downregulation of expression level of gp91(phox), an important component of NADPH oxidase, were observed in Vitex-treated cells. A greater decline in ROS levels along with enhanced apoptosis was observed after treatment with Vitex in combination with SnPP, an inhibitor specific for HO-1. Since NADPH oxidase and HO-1 are closely correlated to redox status associated with intracellular ROS levels, the two enzymes are suggested to be implicated in Vitex-mediated cytotoxicity in HL-60 cells by regulating ROS generation. We also suggest that activation of the p38 MAPK pathway may be dependent on the alterations of intracellular ATP levels, rather than that of intracellular ROS levels. These results may have important implications for appropriate clinical uses of Vitex and provide novel insights into the interaction between Vitex and other conventional drugs capable of affecting intracellular redox status.

Proteomic analysis of the response of α-ketoglutarate-producer Yarrowia lipolytica WSH-Z06 to environmental pH stimuli.

PubMed

Guo, Hongwei; Wan, Hui; Chen, Hongwen; Fang, Fang; Liu, Song; Zhou, Jingwen

2016-10-01

During bioproduction of short-chain carboxylates, a shift in pH is a common strategy for enhancing the biosynthesis of target products. Based on two-dimensional gel electrophoresis, comparative proteomics analysis of general and mitochondrial protein samples was used to investigate the cellular responses to environmental pH stimuli in the α-ketoglutarate overproducer Yarrowia lipolytica WSH-Z06. The lower environmental pH stimuli tensioned intracellular acidification and increased the level of reactive oxygen species (ROS). A total of 54 differentially expressed protein spots were detected, and 11 main cellular processes were identified to be involved in the cellular response to environmental pH stimuli. Slight decrease in cytoplasmic pH enhanced the cellular acidogenicity by elevating expression level of key enzymes in tricarboxylic acid cycle (TCA cycle). Enhanced energy biosynthesis, ROS elimination, and membrane potential homeostasis processes were also employed as cellular defense strategies to compete with environmental pH stimuli. Owing to its antioxidant role of α-ketoglutarate, metabolic flux shifted to α-ketoglutarate under lower pH by Y. lipolytica in response to acidic pH stimuli. The identified differentially expressed proteins provide clues for understanding the mechanisms of the cellular responses and for enhancing short-chain carboxylate production through metabolic engineering or process optimization strategies in combination with manipulation of environmental conditions.

Din7 and Mhr1 expression levels regulate double-strand-break-induced replication and recombination of mtDNA at ori5 in yeast.

PubMed

Ling, Feng; Hori, Akiko; Yoshitani, Ayako; Niu, Rong; Yoshida, Minoru; Shibata, Takehiko

2013-06-01

The Ntg1 and Mhr1 proteins initiate rolling-circle mitochondrial (mt) DNA replication to achieve homoplasmy, and they also induce homologous recombination to maintain mitochondrial genome integrity. Although replication and recombination profoundly influence mitochondrial inheritance, the regulatory mechanisms that determine the choice between these pathways remain unknown. In Saccharomyces cerevisiae, double-strand breaks (DSBs) introduced by Ntg1 at the mitochondrial replication origin ori5 induce homologous DNA pairing by Mhr1, and reactive oxygen species (ROS) enhance production of DSBs. Here, we show that a mitochondrial nuclease encoded by the nuclear gene DIN7 (DNA damage inducible gene) has 5'-exodeoxyribonuclease activity. Using a small ρ(-) mtDNA bearing ori5 (hypersuppressive; HS) as a model mtDNA, we revealed that DIN7 is required for ROS-enhanced mtDNA replication and recombination that are both induced at ori5. Din7 overproduction enhanced Mhr1-dependent mtDNA replication and increased the number of residual DSBs at ori5 in HS-ρ(-) cells and increased deletion mutagenesis at the ori5 region in ρ(+) cells. However, simultaneous overproduction of Mhr1 suppressed all of these phenotypes and enhanced homologous recombination. Our results suggest that after homologous pairing, the relative activity levels of Din7 and Mhr1 modulate the preference for replication versus homologous recombination to repair DSBs at ori5.

Antioxidant N-acetyltransferase Mpr1/2 of industrial baker's yeast enhances fermentation ability after air-drying stress in bread dough.

PubMed

Sasano, Yu; Takahashi, Shunsuke; Shima, Jun; Takagi, Hiroshi

2010-03-31

During bread-making processes, yeast cells are exposed to multiple stresses. Air-drying stress is one of the most harmful stresses by generation of reactive oxygen species (ROS). Previously, we discovered that the novel N-acetyltransferase Mpr1/2 confers oxidative stress tolerance by reducing intracellular ROS level in Saccharomyces cerevisiae Sigma1278b strain. In this study, we revealed that Japanese industrial baker's yeast possesses one MPR gene. The nucleotide sequence of the MPR gene in industrial baker's yeast was identical to the MPR2 gene in Sigma1278b strain. Gene disruption analysis showed that the MPR2 gene in industrial baker's yeast is involved in air-drying stress tolerance by reducing the intracellular oxidation levels. We also found that expression of the Lys63Arg and Phe65Leu variants with enhanced enzymatic activity and stability, respectively, increased the fermentation ability of bread dough after exposure to air-drying stress compared with the wild-type Mpr1. In addition, our recent study showed that industrial baker's yeast cells accumulating proline exhibited enhanced freeze tolerance in bread dough. Proline accumulation also enhanced the fermentation ability after air-drying stress treatment in industrial baker's yeast. Hence, the antioxidant enzyme Mpr1/2 could be promising for breeding novel yeast strains that are tolerant to air-drying stress. Copyright 2010 Elsevier B.V. All rights reserved.

Indoxyl sulfate enhances IL-1β-induced E-selectin expression in endothelial cells in acute kidney injury by the ROS/MAPKs/NFκB/AP-1 pathway.

PubMed

Shen, Wen-Ching; Liang, Chan-Jung; Huang, Tao-Ming; Liu, Chen-Wei; Wang, Shu-Huei; Young, Guang-Huar; Tsai, Jaw-Shiun; Tseng, Ying-Chin; Peng, Yu-Sen; Wu, Vin-Cent; Chen, Yuh-Lien

2016-11-01

Uremic toxins are considered a risk factor for cardiovascular disorders in kidney diseases, but it is not known whether, under inflammatory conditions, they affect adhesion molecule expression on endothelial cells, which may play a critical role in acute kidney injury (AKI). In the present study, in cardiovascular surgery-related AKI patients, who are known to have high plasma levels of the uremic toxin indoxyl sulfate (IS), plasma levels of IL-1β were found to be positively correlated with plasma levels of the adhesion molecule E-selectin. In addition, high E-selectin and IL-1β expression were seen in the kidney of ischemia/reperfusion mice in vivo. We also examined the effects of IS on E-selectin expression by IL-1β-treated human umbilical vein endothelial cells (HUVECs) and the underlying mechanism. IS pretreatment of HUVECs significantly increased IL-1β-induced E-selectin expression, monocyte adhesion, and the phosphorylation of mitogen-activated protein kinases (ERK, p38, and JNK) and transcription factors (NF-κB and AP-1), and phosphorylation was decreased by pretreatment with inhibitors of ERK1/2 (PD98059), p38 MAPK (SB202190), and JNK (SP600125). Furthermore, IS increased IL-1β-induced reactive oxygen species (ROS) production and this effect was inhibited by pretreatment with N-acetylcysteine (a ROS scavenger) or apocynin (a NADPH oxidase inhibitor). Gel shift assays and ChIP-PCR demonstrated that IS enhanced E-selectin expression in IL-1-treated HUVECs by increasing NF-κB and AP-1 DNA-binding activities. Moreover, IS-enhanced E-selectin expression in IL-1β-treated HUVECs was inhibited by Bay11-7082, a NF-κB inhibitor. Thus, IS may play an important role in the development of cardiovascular disorders in kidney diseases during inflammation by increasing endothelial expression of E-selectin.

Modulation of ROS levels in fibroblasts by altering mitochondria regulates the process of wound healing.

PubMed

Janda, Jaroslav; Nfonsam, Valentine; Calienes, Fernanda; Sligh, James E; Jandova, Jana

2016-05-01

Mitochondria are the major source of reactive oxygen species (ROS) in fibroblasts which are thought to be crucial regulators of wound healing with a potential to affect the expression of nuclear genes involved in this process. ROS generated by mitochondria are involved in all stages of tissue repair process but the regulation of ROS-generating system in fibroblasts still remains poorly understood. The purpose of this study was to better understand molecular mechanisms of how the regulation of ROS levels generated by mitochondria may influence the process of wound repair. Cybrid model system of mtDNA variations was used to study the functional consequences of altered ROS levels on wound healing responses in a uniform nuclear background of cultured ρ(0) fibroblasts. Mitochondrial ROS in cybrids were modulated by antioxidants that quench ROS to examine their ability to close the wound. Real-time PCR arrays were used to investigate whether ROS generated by specific mtDNA variants have the ability to alter expression of some key nuclear-encoded genes central to the wound healing response and oxidative stress. Our data suggest levels of mitochondrial ROS affect expression of some nuclear encoded genes central to wound healing response and oxidative stress and modulation of mitochondrial ROS by antioxidants positively affects in vitro process of wound closure. Thus, regulation of mitochondrial ROS-generating system in fibroblasts can be used as effective natural redox-based strategy to help treat non-healing wounds.

MiR-200c regulates ROS-induced apoptosis in murine BV-2 cells by targeting FAP-1.

PubMed

Yu, D S; Lv, G; Mei, X F; Cao, Y; Wang, Y F; Wang, Y S; Bi, Y L

2014-12-02

Objective:Reactive oxygen species (ROS) are significantly upregulated after spinal cord injury (SCI). MicroRNAs (miRNAs) are reported to be widely involved in regulating gene expression. This paper aims to explore the correlation between ROS-induced cell apoptosis and abnormal miRNA expression after SCI.Methods:To profile the expression of miRNAs after SCI, miRNA microarray was applied and the result was verified by reverse transcription quantitative PCR (RT-qPCR). ROS production following H 2 O 2 stimulation was examined using dihydroethidium staining and flow cytometry. The levels of miR-200c after H 2 O 2 treatment were determined using RT-qPCR. Cell viability and apoptosis were examined in murine BV-2 cells transfected with miR-200c mimics, inhibitor or negative control. Immunofluorescence and western blot were used to further explore the effects of miR-200c on Fas-associated phosphatase-1 (FAP-1) expression.Results:MiR-200c was showed to be significantly increased after SCI by miRNA microassay and RT-qPCR. ROS production enhanced miR-200c expression in a dose-dependent manner and induced significant apoptosis in BV-2 cells. The upregulation of miR-200c reduced cell viability and induced BV-2 cell apoptosis. MiR-200c negatively regulated the expression of FAP-1, thereby inducing FAS signaling-induced apoptosis. RT-qPCR analysis showed that the FAP-1-targeting small interfering RNA (siRNA) did not affect the level of miR-200c in murine BV-2 cells. In addition, suppression of FAP-1 by siRNA promoted apoptosis, even in cells that were co-transfected with the miR-200c inhibitor.Conclusions:The current data suggested that miR-200c contributes to apoptosis in murine BV-2 cells by regulating the expression of FAP-1. This proposes a therapeutic target for enhancing neural cell functional recovery after SCI.Spinal Cord advance online publication, 2 December 2014; doi:10.1038/sc.2014.185.

6-Shogaol enhances renal carcinoma Caki cells to TRAIL-induced apoptosis through reactive oxygen species-mediated cytochrome c release and down-regulation of c-FLIP(L) expression.

PubMed

Han, Min Ae; Woo, Seon Min; Min, Kyoung-jin; Kim, Shin; Park, Jong-Wook; Kim, Dong Eun; Kim, Sang Hyun; Choi, Yung Hyun; Kwon, Taeg Kyu

2015-02-25

6-Shogaol, a potent bioactive compound in ginger (Zingiber officinale Roscoe), has been reported for anti-inflammatory and anti-cancer activity. In this study, we investigated the effect of 6-shogaol to enhance tumor necrosis factor-related apoptosis-inducing ligand (TRAIL)-mediated apoptosis. The combined treatment with 6-shogaol and TRAIL markedly induces apoptosis in various cancer cells (renal carcinoma Caki cells, breast carcinoma MDA-MB-231 cells and glioma U118MG cells), but not in normal mesangial cells and normal mouse kidney cells. 6-Shogaol reduced the mitochondrial membrane potential (MMP) and released cytochrome c from mitochondria to cytosol via Bax activation. Furthermore, we found that 6-shogaol induced down-regulation of c-FLIP(L) expression at the post-translational levels and the overexpression of c-FLIP(L) markedly inhibited 6-shogaol plus TRAIL-induced apoptosis. Moreover, 6-shogaol increased reactive oxygen species (ROS) production in Caki cells. Pretreatment with ROS scavengers attenuated 6-shogaol plus TRAIL-induced apoptosis through inhibition of MMP reduction and down-regulation of c-FLIP(L) expression. In addition, 6-gingerol, another phenolic alkanone isolated from ginger, did not enhance TRAIL-induced apoptosis and down-regulate c-FLIP(L) expression. Taken together, our results demonstrated that 6-shogaol enhances TRAIL-mediated apoptosis in renal carcinoma Caki cells via ROS-mediated cytochrome c release and down-regulation of c-FLIP(L) expression. Copyright © 2015 Elsevier Ireland Ltd. All rights reserved.

Hafnium-doped hydroxyapatite nanoparticles with ionizing radiation for lung cancer treatment.

PubMed

Chen, Min-Hua; Hanagata, Nobutaka; Ikoma, Toshiyuki; Huang, Jian-Yuan; Li, Keng-Yuan; Lin, Chun-Pin; Lin, Feng-Huei

2016-06-01

Recently, photodynamic therapy (PDT) is one of the new clinical options by generating cytotoxic reactive oxygen species (ROS) to kill cancer cells. However, the optical approach of PDT is limited by tissue penetration depth of visible light. In this study, we propose that a ROS-enhanced nanoparticle, hafnium-doped hydroxyapatite (Hf:HAp), which is a material to yield large quantities of ROS inside the cells when the nanoparticles are bombarded with high penetrating power of ionizing radiation. Hf:HAp nanoparticles are generated by wet chemical precipitation with total doping concentration of 15mol% Hf(4+) relative to Ca(2+) in HAp host material. The results show that the HAp particles could be successfully doped with Hf ions, resulted in the formation of nano-sized rod-like shape and with pH-dependent solubility. The impact of ionizing radiation on Hf:HAp nanoparticles is assessed by using in-vitro and in-vivo model using A549 cell line. The 2',7'-dichlorofluorescein diacetate (DCFH-DA) results reveal that after being exposed to gamma rays, Hf:HAp could significantly lead to the formation of ROS in cells. Both cell viability (WST-1) and cytotoxicity (LDH) assay show the consistent results that A549 lung cancer cell lines are damaged with changes in the cells' ROS level. The in-vivo studies further demonstrate that the tumor growth is inhibited owing to the cells apoptosis when Hf:HAp nanoparticles are bombarded with ionizing radiation. This finding offer a new therapeutic method of interacting with ionizing radiation and demonstrate the potential of Hf:HAp nanoparticles in tumor treatment, such as being used in a palliative treatment after lung surgical procedure. Photodynamic therapy (PDT) is one of the new clinical options by generating cytotoxic reactive oxygen species (ROS) to kill cancer cells. Unfortunately, the approach of PDT is usually limited to the treatment of systemic disease and deeper tumor, due to the limited tissue penetration depth of visible light (620-690nm). Here we report a ROS-enhanced nanoparticle, hafnium-doped hydroxyapatite (Hf:HAp), which can trigger ROS when particles are irradiated with high penetrating power of ionizing radiation. The present study provides quantitative data relating ROS generation and the therapeutic effect of Hf:HAp nanoparticles in lung cancer cells. As such, this material has opened an innovative window for deeper tumor and systemic disease treatment. Copyright © 2016 Acta Materialia Inc. Published by Elsevier Ltd. All rights reserved.

A reactive oxygen species activation mechanism contributes to JS-K-induced apoptosis in human bladder cancer cells.

PubMed

Qiu, Mingning; Chen, Lieqian; Tan, Guobin; Ke, Longzhi; Zhang, Sai; Chen, Hege; Liu, Jianjun

2015-10-13

Reactive oxygen species (ROS) and cellular oxidant stress are regulators of cancer cells. The alteration of redox status, which is induced by increased generation of ROS, results in increased vulnerability to oxidative stress. The aim of this study is to investigate the influence of O2-(2,4-dinitrophenyl) 1-[(4-ethoxycarbonyl)piperazin-1-yl]diazen-1-ium-1,2-diolate (JS-K, C13H16N6O8) on proliferation and apoptosis in bladder cancer cells and explored possible ROS-related mechanisms. Our results indicated that JS-K could suppress bladder cancer cell proliferation in a concentration- and time-dependent manner and induce apoptosis and ROS accumulation in a concentration-dependent manner. With increasing concentrations of JS-K, expression of proteins that are involved in cell apoptosis increased in a concentration-dependent manner. Additionally, the antioxidant N-acetylcysteine (NAC) reversed JS-K-induced cell apoptosis; conversely, the prooxidant oxidized glutathione (GSSG) exacerbated JS-K-induced cell apoptosis. Furthermore, we found that nitrites, which were generated from the oxidation of JS-K-released NO, induced apoptosis in bladder cancer cells to a lower extent through the ROS-related pathway. In addition, JS-K was shown to enhance the chemo-sensitivity of doxorubicin in bladder cancer cells. Taken together, the data suggest that JS-K-released NO induces bladder cancer cell apoptosis by increasing ROS levels, and nitrites resulting from oxidation of NO have a continuous apoptosis-inducing effect.

A reactive oxygen species activation mechanism contributes to JS-K-induced apoptosis in human bladder cancer cells

PubMed Central

Qiu, Mingning; Chen, Lieqian; Tan, Guobin; Ke, Longzhi; Zhang, Sai; Chen, Hege; Liu, Jianjun

2015-01-01

Reactive oxygen species (ROS) and cellular oxidant stress are regulators of cancer cells. The alteration of redox status, which is induced by increased generation of ROS, results in increased vulnerability to oxidative stress. The aim of this study is to investigate the influence of O2-(2,4-dinitrophenyl) 1-[(4-ethoxycarbonyl)piperazin-1-yl]diazen-1-ium-1,2-diolate (JS-K, C13H16N6O8) on proliferation and apoptosis in bladder cancer cells and explored possible ROS-related mechanisms. Our results indicated that JS-K could suppress bladder cancer cell proliferation in a concentration- and time-dependent manner and induce apoptosis and ROS accumulation in a concentration-dependent manner. With increasing concentrations of JS-K, expression of proteins that are involved in cell apoptosis increased in a concentration-dependent manner. Additionally, the antioxidant N-acetylcysteine (NAC) reversed JS-K-induced cell apoptosis; conversely, the prooxidant oxidized glutathione (GSSG) exacerbated JS-K-induced cell apoptosis. Furthermore, we found that nitrites, which were generated from the oxidation of JS-K-released NO, induced apoptosis in bladder cancer cells to a lower extent through the ROS-related pathway. In addition, JS-K was shown to enhance the chemo-sensitivity of doxorubicin in bladder cancer cells. Taken together, the data suggest that JS-K-released NO induces bladder cancer cell apoptosis by increasing ROS levels, and nitrites resulting from oxidation of NO have a continuous apoptosis-inducing effect. PMID:26458509

Overexpressing Ferredoxins in Chlamydomonas reinhardtii Increase Starch and Oil Yields and Enhance Electric Power Production in a Photo Microbial Fuel Cell

PubMed Central

Huang, Li-Fen; Lin, Ji-Yu; Pan, Kui-You; Huang, Chun-Kai; Chu, Ying-Kai

2015-01-01

Ferredoxins (FDX) are final electron carrier proteins in the plant photosynthetic pathway, and function as major electron donors in diverse redox-driven metabolic pathways. We previously showed that overexpression of a major constitutively expressed ferredoxin gene PETF in Chlamydomonas decreased the reactive oxygen species (ROS) level and enhanced tolerance to heat stress. In addition to PETF, an endogenous anaerobic induced FDX5 was overexpressed in transgenic Chlamydomonas lines here to address the possible functions of FDX5. All the independent FDX transgenic lines showed decreased cellular ROS levels and enhanced tolerance to heat and salt stresses. The transgenic Chlamydomonas lines accumulated more starch than the wild-type line and this effect increased almost three-fold in conditions of nitrogen depletion. Furthermore, the lipid content was higher in the transgenic lines than in the wild-type line, both with and without nitrogen depletion. Two FDX-overexpressing Chlamydomonas lines were assessed in a photo microbial fuel cell (PMFC); power density production by the transgenic lines was higher than that of the wild-type cells. These findings suggest that overexpression of either PETF or FDX5 can confer tolerance against heat and salt stresses, increase starch and oil production, and raise electric power density in a PMFC. PMID:26287179

N-Acetyl-L-cysteine protects thyroid cells against DNA damage induced by external and internal irradiation.

PubMed

Kurashige, Tomomi; Shimamura, Mika; Nagayama, Yuji

2017-11-01

We evaluated the effect of the antioxidant N-acetyl-L-cysteine (NAC) on the levels of reactive oxygen species (ROS), DNA double strand breaks (DSB) and micronuclei (MN) induced by internal and external irradiation using a rat thyroid cell line PCCL3. In internal irradiation experiments, ROS and DSB levels increased immediately after 131 I addition and then gradually declined, resulting in very high levels of MN at 24 and 48 h. NAC administration both pre- and also post- 131 I addition suppressed ROS, DSB and MN. In external irradiation experiments with a low dose (0.5 Gy), ROS and DSB increased shortly and could be prevented by NAC administration pre-, but not post-irradiation. In contrast, external irradiation with a high dose (5 Gy) increased ROS and DSB in a bimodal way: ROS and DSB levels increased immediately after irradiation, quickly returned to the basal levels and gradually rose again after >24 h. The second phase was in parallel with an increase in 4-hydroxy-2-nonenal. The number of MN induced by the second wave of ROS/DSB elevations was much higher than that by the first peak. In this situation, NAC administered pre- and post-irradiation comparably suppressed MN induced by a delayed ROS elevation. In conclusion, a prolonged ROS increase during internal irradiation and a delayed ROS increase after external irradiation with a high dose caused serious DNA damage, which were efficiently prevented by NAC. Thus, NAC administration even both after internal or external irradiation prevents ROS increase and eventual DNA damage.

OxLDL enhances L-type Ca2+ currents via lysophosphatidylcholine-induced mitochondrial reactive oxygen species (ROS) production.

PubMed

Fearon, Ian M

2006-03-01

To examine the mechanisms underlying oxidised LDL- (oxLDL)-induced alterations in Ca(2+) currents, an effect which underlies altered vascular contractility and cardiac myocyte function. Ca(2+) currents (I(Ca)) were recorded by whole-cell patch-clamp in HEK293 cells expressing L-type Ca(2+) channel alpha(1C) subunits or isolated rat ventricular myocytes. oxLDL (but not native LDL) significantly enhanced recombinant I(Ca), an effect mimicked by 1 microM lysophosphatidylcholine (LPC). LPC failed to enhance I(Ca) either in mitochondrial electron transport chain-depleted rho(0) cells, or in the presence of rotenone (1 microM), or MPP(+) (10 microM). The LPC response was similarly ablated by ascorbate (200 microM) or TROLOX (500 microM) and by the mitochondria-targeted antioxidant, MitoQ (250 nM). In myocytes, enhancement of I(Ca) due to LPC was similarly abrogated with rotenone and MitoQ. These data suggest that LPC enhanced recombinant Ca(2+) currents due to increased mitochondrial ROS production. In support with this, LPC enhanced fluorescence in HEK293 cells and cardiac myocytes loaded with a ROS-sensitive mitochondrial dye, reduced mitotracker red. LPC up-regulates L-type Ca(2+) currents due to altered mitochondrial ROS production, an effect which mediates the response of the native I(Ca) in cardiac myocytes to oxLDL.

Knockdown of ferroportin accelerates erastin-induced ferroptosis in neuroblastoma cells.

PubMed

Geng, N; Shi, B-J; Li, S-L; Zhong, Z-Y; Li, Y-C; Xua, W-L; Zhou, H; Cai, J-H

2018-06-01

Ferroptosis is a new-found iron-dependent form of non-apoptotic regulated cell death (RCD), which is activated on therapy with several antitumor agents, but the potential mechanism remains unclear. Erastin, exhibiting selectivity for RAS-mutated cancer cells, induces ferroptosis by increasing iron and lipid reactive oxygen species (ROS) levels in cell. Ferroportin (Fpn), the sole iron export protein, participates in the regulation of intracellular iron concentration. In this study, we investigated the role of Fpn on ferroptosis induced by erastin in SH-SY5Y cells. The cell viability was determined by CellTiter 96® AQueous Non-Radioactive Cell Proliferation Assay kit. The activity of caspase-3 was measured by ELISA kit. qRT-PCR was performed to examine the mRNA expression of Fpn. Western blot assay was conducted to examine the expression level of marker proteins. Specific commercial kits were used to examine the levels of MDA, ROS and iron in cells, respectively. Ferroptosis was evaluated by intracellular lipid ROS level and iron concentration. Hepcidin could prevent erastin-induced ferroptosis by degrading Fpn. Erastin (5 μg/mL) was observed to induce ferroptosis in neuroblastoma cells at 6 hours, which was promoted by knockdown of Fpn. The expression of Fpn gene and protein was decreased in SH-SY5Y cells treated with erastin. After treatment with erastin, Fpn siRNA transfection in SH-SY5Y cells was able to accelerate ferroptosis-associated phenotypic changes. Fpn acted as a negative regulator of ferroptosis by reducing intracellular iron concentration. Knockdown of Fpn enhanced anticancer activity of erastin. These results suggested that knockdown of Fpn accelerated erastin-induced ferroptosis by increasing iron-dependent lipid ROS accumulation, highlighting Fpn as a potential therapeutic target site for neuroblastoma. Thus, Fpn inhibitors may provide new access for chemosensitization of neuroblastoma.

[Exploration of relationship between the expression level of DNA polymerase beta and 60Co gamma-ray radiosensitivity].

PubMed

Cui, Jie; Xu, Xin; Yang, Mo; Chen, Chen; Zhao, Wei; Wu, Mei; Zhang, Zun-zhen

2011-11-01

To explore the relationship between the expression level of DNA polymerase beta (pol beta) and 60Co gamma-ray radiosensitivity and provide a basis on improving the efficiency of radiotherapy theoretically. pol beta wild-type cells (pol beta +/+), pol beta null cells (pol beta -/-) and pol beta overexpressed cells (polp beta oe) were applied as a model system. The radiosensitivity of 60Co gamma-ray on the cell was detected by MTT assay and clone formation assay. The DCFH-DA fluorescent probe was used to examine the cellular ROS after 60Co gamma-rays radiation. MTT assay showed that after radiation by 60Co gamma-rays followed with 72 h incubation, the cell viabilities in the three kinds of cells decreased significantly with a dose-response relationship (r-/+ = -0.976, r-/- = -0.977, r(oe) = -0.982, P<0.05). In addition, the viability of pol beta -/- cell was lower than those of other two kinds of cells at the same dose (P<0.05). Likewise, the colony number and colony formation rate in all tested cells also decreased after exposure to 60Co gamma-rays. The ROS level in the three kinds of cells was enhanced after treatment with 60Co gamma-ray, and the ROS level in pol beta -/- cells was much higher than that in the other two kinds of cells (P<0.05). Cell death caused by 60Co gamma-ray may associated with the DNA oxidative damage mediated by ROS; Overexpression of pol beta could protect against oxidative DNA damage, thus the cell apoptosis/death, thereby leading to reducing the radiosensitivity of 60Co gamma-rays, while null of DNA pol beta could increase radiosensitivity of 60Co gamma-rays by compromising the DNA repair.

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.

COX-2 is involved in vascular oxidative stress and endothelial dysfunction of renal interlobar arteries from obese Zucker rats.

PubMed

Muñoz, Mercedes; Sánchez, Ana; Pilar Martínez, María; Benedito, Sara; López-Oliva, Maria-Elvira; García-Sacristán, Albino; Hernández, Medardo; Prieto, Dolores

2015-07-01

Obesity is related to vascular dysfunction through inflammation and oxidative stress and it has been identified as a risk factor for chronic renal disease. In the present study, we assessed the specific relationships among reactive oxygen species (ROS), cyclooxygenase 2 (COX-2), and endothelial dysfunction in renal interlobar arteries from a genetic model of obesity/insulin resistance, the obese Zucker rats (OZR). Relaxations to acetylcholine (ACh) were significantly reduced in renal arteries from OZR compared to their counterpart, the lean Zucker rat (LZR), suggesting endothelial dysfunction. Blockade of COX with indomethacin and with the selective blocker of COX-2 restored the relaxations to ACh in obese rats. Selective blockade of the TXA2/PGH2 (TP) receptor enhanced ACh relaxations only in OZR, while inhibition of the prostacyclin (PGI2) receptor (IP) enhanced basal tone and inhibited ACh vasodilator responses only in LZR. Basal production of superoxide was increased in arteries of OZR and involved NADPH and xanthine oxidase activation and NOS uncoupling. Under conditions of NOS blockade, ACh induced vasoconstriction and increased ROS generation that were augmented in arteries from OZR and blunted by COX-2 inhibition and by the ROS scavenger tempol. Hydrogen peroxide (H2O2) evoked both endothelium- and vascular smooth muscle (VSM)-dependent contractions, as well as ROS generation that was reduced by COX-2 inhibition. In addition, COX-2 expression was enhanced in both VSM and endothelium of renal arteries from OZR. These results suggest that increased COX-2-dependent vasoconstriction contributes to renal endothelial dysfunction through enhanced (ROS) generation in obesity. COX-2 activity is in turn upregulated by ROS. Copyright © 2015 Elsevier Inc. All rights reserved.

Endogenous lycopene improves ethanol production under acetic acid stress in Saccharomyces cerevisiae.

PubMed

Pan, Shuo; Jia, Bin; Liu, Hong; Wang, Zhen; Chai, Meng-Zhe; Ding, Ming-Zhu; Zhou, Xiao; Li, Xia; Li, Chun; Li, Bing-Zhi; Yuan, Ying-Jin

2018-01-01

Acetic acid, generated from the pretreatment of lignocellulosic biomass, is a significant obstacle for lignocellulosic ethanol production. Reactive oxidative species (ROS)-mediated cell damage is one of important issues caused by acetic acid. It has been reported that decreasing ROS level can improve the acetic acid tolerance of Saccharomyces cerevisiae . Lycopene is known as an antioxidant. In the study, we investigated effects of endogenous lycopene on cell growth and ethanol production of S. cerevisiae in acetic acid media. By accumulating endogenous lycopene during the aerobic fermentation of the seed stage, the intracellular ROS level of strain decreased to 1.4% of that of the control strain during ethanol fermentation. In the ethanol fermentation system containing 100 g/L glucose and 5.5 g/L acetic acid, the lag phase of strain was 24 h shorter than that of control strain. Glucose consumption rate and ethanol titer of yPS002 got to 2.08 g/L/h and 44.25 g/L, respectively, which were 2.6- and 1.3-fold of the control strain. Transcriptional changes of INO1 gene and CTT1 gene confirmed that endogenous lycopene can decrease oxidative stress and improve intracellular environment. Biosynthesis of endogenous lycopene is first associated with enhancing tolerance to acetic acid in S. cerevisiae . We demonstrate that endogenous lycopene can decrease intracellular ROS level caused by acetic acid, thus increasing cell growth and ethanol production. This work innovatively   puts forward a new strategy for second generation bioethanol production during lignocellulosic fermentation.

Production of ozone and reactive oxygen species after welding.

PubMed

Liu, H H; Wu, Y C; Chen, H L

2007-11-01

Many toxic substances including heavy metals, ozone, carbon monoxide, carbon dioxide, and nitrogen oxides are generated during welding. Ozone (O(3)) is a strong oxidant that generates reactive oxygen species (ROS) in tissue, and ambient ROS exposure associated with particles has been determined to cause DNA damage. Ozone is produced within 30 seconds during welding. However, the length of time that O(3) remains in the air after welding is completed (post-welding) is unknown. The current study aimed to assess the distributions of ambient ROS and O(3) before the start of welding (pre-welding), during welding, and after welding. The highest O(3) levels, equal to 195 parts per billion (ppb), appeared during welding. Ozone levels gradually decreased to 60 ppb 10 minutes after the welding was completed. The highest ROS level was found in samples taken during welding, followed by samples taken after the welding was completed. The lowest ROS level was found in samples taken before the welding had started. Ozone and ROS levels were poorly correlated, but a similar trend was found for O(3) and ROS levels in particles (microM/mg). Although particles were not generated after welding, ROS and O(3) still persisted for more than 10 minutes. Meanwhile, because O(3) continues after welding, how long the occupational protective system should be used depends on the welding materials and the methods used. In addition, the relationship between metal fumes and ROS generation during the welding process should be further investigated.

Enhanced oxidative stress in the jasmonic acid-deficient tomato mutant def-1 exposed to NaCl stress.

PubMed

Abouelsaad, Ibrahim; Renault, Sylvie

2018-04-21

Jasmonic acid (JA) has been mostly studied in responses to biotic stresses, such as herbivore attack and pathogenic infection. More recently, the involvement of JA in abiotic stresses including salinity was highlighted; yet, its role in salt stress remained unclear. In the current study, we compared the physiological and biochemical responses of wild-type (WT) tomato (Solanum lycopersicum) cv Castlemart and its JA-deficient mutant defenseless-1 (def-1) under salt stress to investigate the role of JA. Plant growth, photosynthetic pigment content, ion accumulation, oxidative stress-related parameters, proline accumulation and total phenolic compounds, in addition to both enzymatic and non-enzymatic antioxidant activities, were measured in both genotypes after 14 days of 100 mM NaCl treatment. Although we observed in both genotypes similar growth pattern and sodium, calcium and potassium levels in leaves under salt stress, def-1 plants exhibited a more pronounced decrease of nitrogen content in both leaves and roots and a slightly higher level of sodium in roots compared to WT plants. In addition, def-1 plants exposed to salt stress showed reactive oxygen species (ROS)-associated injury phenotypes. These oxidative stress symptoms in def-1 were associated with lower activity of both enzymatic antioxidants and non-enzymatic antioxidants. Furthermore, the levels of the non-enzymatic ROS scavengers proline and total phenolic compounds increased in both genotypes exposed to salt stress, with a higher amount of proline in the WT plants. Overall the results of this study suggest that endogenous JA mainly enhanced tomato salt tolerance by maintaining ROS homeostasis. Copyright © 2018 Elsevier GmbH. All rights reserved.

Mitochondrial Reactive Oxygen Species (ROS) and ROS-Induced ROS Release

PubMed Central

Zorov, Dmitry B.; Juhaszova, Magdalena; Sollott, Steven J.

2014-01-01

Byproducts of normal mitochondrial metabolism and homeostasis include the buildup of potentially damaging levels of reactive oxygen species (ROS), Ca2+, etc., which must be normalized. Evidence suggests that brief mitochondrial permeability transition pore (mPTP) openings play an important physiological role maintaining healthy mitochondria homeostasis. Adaptive and maladaptive responses to redox stress may involve mitochondrial channels such as mPTP and inner membrane anion channel (IMAC). Their activation causes intra- and intermitochondrial redox-environment changes leading to ROS release. This regenerative cycle of mitochondrial ROS formation and release was named ROS-induced ROS release (RIRR). Brief, reversible mPTP opening-associated ROS release apparently constitutes an adaptive housekeeping function by the timely release from mitochondria of accumulated potentially toxic levels of ROS (and Ca2+). At higher ROS levels, longer mPTP openings may release a ROS burst leading to destruction of mitochondria, and if propagated from mitochondrion to mitochondrion, of the cell itself. The destructive function of RIRR may serve a physiological role by removal of unwanted cells or damaged mitochondria, or cause the pathological elimination of vital and essential mitochondria and cells. The adaptive release of sufficient ROS into the vicinity of mitochondria may also activate local pools of redox-sensitive enzymes involved in protective signaling pathways that limit ischemic damage to mitochondria and cells in that area. Maladaptive mPTP- or IMAC-related RIRR may also be playing a role in aging. Because the mechanism of mitochondrial RIRR highlights the central role of mitochondria-formed ROS, we discuss all of the known ROS-producing sites (shown in vitro) and their relevance to the mitochondrial ROS production in vivo. PMID:24987008

Role of membrane cholesterol in spontaneous exocytosis at frog neuromuscular synapses: reactive oxygen species–calcium interplay

PubMed Central

Petrov, Alexey M; Yakovleva, Anastasiya A; Zefirov, Andrey L

2014-01-01

Using electrophysiological and optical techniques, we studied the mechanisms by which cholesterol depletion stimulates spontaneous transmitter release by exocytosis at the frog neuromuscular junction. We found that methyl-β-cyclodextrin (MCD, 10 mm)-mediated exhaustion of cholesterol resulted in the enhancement of reactive oxygen species (ROS) production, which was prevented by the antioxidant N-acetyl cysteine (NAC) and the NADPH oxidase inhibitor apocynin. An increase in ROS levels occurred both extra- and intracellularly, and it was associated with lipid peroxidation in synaptic regions. Cholesterol depletion provoked a rise in the intracellular Ca2+ concentration, which was diminished by NAC and transient receptor potential vanilloid (TRPV) channel blockers (ruthenium red and capsazepine). By contrast, the MCD-induced rise in [Ca2+]i remained unaffected if Ca2+ release from endoplasmic stores was blocked by TMB8 (8-(diethylamino)octyl-3,4,5-trimethoxybenzoate hydrochloride). The effects of cholesterol depletion on spontaneous release and exocytosis were significantly reduced by the antioxidant, intracellular Ca2+ chelation with BAPTA-AM and blockers of TRPV channels. Bath application of the calcineurin antagonist cyclosporine A blocked MCD-induced enhancement of spontaneous release/exocytosis, whereas okadaic acid, an inhibitor of phosphatases PP1 and PP2A, had no effect. Thus, our findings indicate that enhancement of spontaneous exocytosis induced by cholesterol depletion may depend on ROS generation, leading to an influx of Ca2+ via TRPV channels and, subsequently, activation of calcineurin. PMID:25326454

Cell Intrinsic Galectin-3 Attenuates Neutrophil ROS-Dependent Killing of Candida by Modulating CR3 Downstream Syk Activation

PubMed Central

Wu, Sheng-Yang; Huang, Juin-Hua; Chen, Wen-Yu; Chan, Yi-Chen; Lin, Chun-Hung; Chen, Yee-Chun; Liu, Fu-Tong; Wu-Hsieh, Betty A.

2017-01-01

Invasive candidiasis is a leading cause of nosocomial bloodstream infection. Neutrophils are the important effector cells in host resistance to candidiasis. To investigate the modulation of neutrophil fungicidal function will advance our knowledge on the control of candidiasis. While recombinant galectin-3 enhances neutrophil phagocytosis of Candida, we found that intracellular galectin-3 downregulates neutrophil fungicidal functions. Co-immunoprecipitation and immunofluorescence staining reveal that cytosolic gal3 physically interacts with Syk in neutrophils after Candida stimulation. Gal3−/− neutrophils have higher level of Syk activation as well as greater abilities to generate reactive oxygen species (ROS) and kill Candida than gal3+/+ cells. While galectin-3 deficiency modulates neutrophil and macrophage activation and the recruitment of monocytes and dendritic cells, the deficiency does not affect the numbers of infiltrating neutrophils or macrophages. Galectin-3 deficiency ameliorates systemic candidiasis by reducing fungal burden, renal pathology, and mortality. Adoptive transfer experiments demonstrate that cell intrinsic galectin-3 negatively regulates neutrophil effector functions against candidiasis. Reducing galectin-3 expression or activity by siRNA or gal3 inhibitor TD139 enhances human neutrophil ROS production. Mice treated with TD139 have enhanced ability to clear the fungus. Our work unravels the mechanism by which galectin-3 regulates Syk-dependent neutrophil fungicidal functions and raises the possibility that blocking gal3 in neutrophils may be a promising therapeutic strategy for treating systemic candidiasis. PMID:28217127

Multifunctional Gadolinium-Doped Mesoporous TiO2 Nanobeads: Photoluminescence, Enhanced Spin Relaxation, and Reactive Oxygen Species Photogeneration, Beneficial for Cancer Diagnosis and Treatment.

PubMed

Imani, Roghayeh; Dillert, Ralf; Bahnemann, Detlef W; Pazoki, Meysam; Apih, Tomaž; Kononenko, Veno; Repar, Neža; Kralj-Iglič, Veronika; Boschloo, Gerrit; Drobne, Damjana; Edvinsson, Tomas; Iglič, Aleš

2017-05-01

Materials with controllable multifunctional abilities for optical imaging (OI) and magnetic resonant imaging (MRI) that also can be used in photodynamic therapy are very interesting for future applications. Mesoporous TiO 2 sub-micrometer particles are doped with gadolinium to improve photoluminescence functionality and spin relaxation for MRI, with the added benefit of enhanced generation of reactive oxygen species (ROS). The Gd-doped TiO 2 exhibits red emission at 637 nm that is beneficial for OI and significantly improves MRI relaxation times, with a beneficial decrease in spin-lattice and spin-spin relaxation times. Density functional theory calculations show that Gd 3+ ions introduce impurity energy levels inside the bandgap of anatase TiO 2 , and also create dipoles that are beneficial for charge separation and decreased electron-hole recombination in the doped lattice. The Gd-doped TiO 2 nanobeads (NBs) show enhanced ability for ROS monitored via • OH radical photogeneration, in comparison with undoped TiO 2 nanobeads and TiO 2 P25, for Gd-doping up to 10%. Cellular internalization and biocompatibility of TiO 2 @xGd NBs are tested in vitro on MG-63 human osteosarcoma cells, showing full biocompatibility. After photoactivation of the particles, anticancer trace by means of ROS photogeneration is observed just after 3 min irradiation. © 2017 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Endothelial Cells Derived from the Blood-Brain Barrier and Islets of Langerhans Differ in their Response to the Effects of Bilirubin on Oxidative Stress Under Hyperglycemic Conditions.

PubMed

Kapitulnik, Jaime; Benaim, Clara; Sasson, Shlomo

2012-01-01

Unconjugated bilirubin (UCB) is a neurotoxic degradation product of heme. Its toxic effects include induction of apoptosis, and ultimately neuronal cell death. However, at low concentrations, UCB is a potent antioxidant that may protect cells and tissues against oxidative stress by neutralizing toxic metabolites such as reactive oxygen species (ROS). High glucose levels (hyperglycemia) generate reactive metabolites. Endothelial cell dysfunction, an early vascular complication in diabetes, has been associated with hyperglycemia-induced oxidative stress. Both glucose and UCB are substrates for transport proteins in microvascular endothelial cells of the blood-brain barrier (BBB). In the current study we show that UCB (1-40 μM) induces apoptosis and reduces survival of bEnd3 cells, a mouse brain endothelial cell line which serves as an in vitro model of the BBB. These deleterious effects of UCB were enhanced in the presence of high glucose (25 mM) levels. Interestingly, the bEnd3 cells exhibited an increased sensitivity to the apoptotic effects of UCB when compared to the MS1 microcapillary endothelial cell line. MS1 cells originate from murine pancreatic islets of Langerhans, and are devoid of the barrier characteristics of BBB-derived endothelial cells. ROS production was increased in both bEnd3 and MS1 cells exposed to high glucose, as compared with cells exposed to normal (5.5 mM) glucose levels. While UCB (0.1-40 μM) did not alter ROS production in cells exposed to normal glucose, relatively low ("physiological") UCB concentrations (0.1-5 μM) attenuated ROS generation in both cell lines exposed to high glucose levels. Most strikingly, higher UCB concentrations (20-40 μM) increased ROS generation in bEnd3 cells exposed to high glucose, but not in similarly treated MS1 cells. These results may be of critical importance for understanding the vulnerability of the BBB endothelium upon exposure to increasing UCB levels under hyperglycemic conditions.

Endothelial Cells Derived from the Blood-Brain Barrier and Islets of Langerhans Differ in their Response to the Effects of Bilirubin on Oxidative Stress Under Hyperglycemic Conditions

PubMed Central

Kapitulnik, Jaime; Benaim, Clara; Sasson, Shlomo

2012-01-01

Unconjugated bilirubin (UCB) is a neurotoxic degradation product of heme. Its toxic effects include induction of apoptosis, and ultimately neuronal cell death. However, at low concentrations, UCB is a potent antioxidant that may protect cells and tissues against oxidative stress by neutralizing toxic metabolites such as reactive oxygen species (ROS). High glucose levels (hyperglycemia) generate reactive metabolites. Endothelial cell dysfunction, an early vascular complication in diabetes, has been associated with hyperglycemia-induced oxidative stress. Both glucose and UCB are substrates for transport proteins in microvascular endothelial cells of the blood-brain barrier (BBB). In the current study we show that UCB (1–40 μM) induces apoptosis and reduces survival of bEnd3 cells, a mouse brain endothelial cell line which serves as an in vitro model of the BBB. These deleterious effects of UCB were enhanced in the presence of high glucose (25 mM) levels. Interestingly, the bEnd3 cells exhibited an increased sensitivity to the apoptotic effects of UCB when compared to the MS1 microcapillary endothelial cell line. MS1 cells originate from murine pancreatic islets of Langerhans, and are devoid of the barrier characteristics of BBB-derived endothelial cells. ROS production was increased in both bEnd3 and MS1 cells exposed to high glucose, as compared with cells exposed to normal (5.5 mM) glucose levels. While UCB (0.1–40 μM) did not alter ROS production in cells exposed to normal glucose, relatively low (“physiological”) UCB concentrations (0.1–5 μM) attenuated ROS generation in both cell lines exposed to high glucose levels. Most strikingly, higher UCB concentrations (20–40 μM) increased ROS generation in bEnd3 cells exposed to high glucose, but not in similarly treated MS1 cells. These results may be of critical importance for understanding the vulnerability of the BBB endothelium upon exposure to increasing UCB levels under hyperglycemic conditions. PMID:22811666

DUOX enzyme activity promotes AKT signalling in prostate cancer cells.

PubMed

Pettigrew, Christopher A; Clerkin, John S; Cotter, Thomas G

2012-12-01

Reactive oxygen species (ROS) and oxidative stress are related to tumour progression, and high levels of ROS have been observed in prostate tumours compared to normal prostate. ROS can positively influence AKT signalling and thereby promote cell survival. The aim of this project was to establish whether the ROS generated in prostate cancer cells positively regulate AKT signalling and enable resistance to apoptotic stimuli. In PC3 cells, dual oxidase (DUOX) enzymes actively generate ROS, which inactivate phosphatases, thereby maintaining AKT phosphorylation. Inhibition of DUOX by diphenylene iodium (DPI), intracellular calcium chelation and small-interfering RNA (siRNA) resulted in lower ROS levels, lower AKT and glycogen synthase kinase 3β (GSK3β) phosphorylation, as well as reduced cell viability and increased susceptibility to apoptosis stimulating fragment (FAS) induced apoptosis. This report shows that ROS levels in PC3 cells are constitutively maintained by DUOX enzymes, and these ROS positively regulate AKT signalling through inactivating phosphatases, leading to increased resistance to apoptosis.

Mitochondria-Targeted Antioxidant Prevents Cardiac Dysfunction Induced by Tafazzin Gene Knockdown in Cardiac Myocytes

PubMed Central

He, Quan; Harris, Nicole; Ren, Jun; Han, Xianlin

2014-01-01

Tafazzin, a mitochondrial acyltransferase, plays an important role in cardiolipin side chain remodeling. Previous studies have shown that dysfunction of tafazzin reduces cardiolipin content, impairs mitochondrial function, and causes dilated cardiomyopathy in Barth syndrome. Reactive oxygen species (ROS) have been implicated in the development of cardiomyopathy and are also the obligated byproducts of mitochondria. We hypothesized that tafazzin knockdown increases ROS production from mitochondria, and a mitochondria-targeted antioxidant prevents tafazzin knockdown induced mitochondrial and cardiac dysfunction. We employed cardiac myocytes transduced with an adenovirus containing tafazzin shRNA as a model to investigate the effects of the mitochondrial antioxidant, mito-Tempo. Knocking down tafazzin decreased steady state levels of cardiolipin and increased mitochondrial ROS. Treatment of cardiac myocytes with mito-Tempo normalized tafazzin knockdown enhanced mitochondrial ROS production and cellular ATP decline. Mito-Tempo also significantly abrogated tafazzin knockdown induced cardiac hypertrophy, contractile dysfunction, and cell death. We conclude that mitochondria-targeted antioxidant prevents cardiac dysfunction induced by tafazzin gene knockdown in cardiac myocytes and suggest mito-Tempo as a potential therapeutic for Barth syndrome and other dilated cardiomyopathies resulting from mitochondrial oxidative stress. PMID:25247053

Durum wheat dehydrin (DHN-5) confers salinity tolerance to transgenic Arabidopsis plants through the regulation of proline metabolism and ROS scavenging system.

PubMed

Saibi, Walid; Feki, Kaouthar; Ben Mahmoud, Rihem; Brini, Faiçal

2015-11-01

The wheat dehydrin (DHN-5) gives birth to salinity tolerance to transgenic Arabidopsis plants by the regulation of proline metabolism and the ROS scavenging system. Dehydrins (DHNs) are involved in plant abiotic stress tolerance. In this study, we reported that salt tolerance of transgenic Arabidopsis plants overexpressing durum wheat dehydrin (DHN-5) was closely related to the activation of the proline metabolism enzyme (P5CS) and some antioxidant biocatalysts. Indeed, DHN-5 improved P5CS activity in the transgenic plants generating a significant proline accumulation. Moreover, salt tolerance of Arabidopsis transgenic plants was accompanied by an excellent activation of antioxidant enzymes like catalase (CAT), superoxide dismutase (SOD) and peroxide dismutase (POD) and generation of a lower level of hydrogen peroxide (H2O2) in leaves compared to the wild-type plants. The enzyme activities were enhanced in these transgenic plants in the presence of exogenous proline. Nevertheless, proline accumulation was slightly reduced in transgenic plants promoting chlorophyll levels. All these results suggest the crucial role of DHN-5 in response to salt stress through the activation of enzymes implicated in proline metabolism and in ROS scavenging enzymes.

Ketones prevent synaptic dysfunction induced by mitochondrial respiratory complex inhibitors

PubMed Central

Kim, Do Young; Vallejo, Johana; Rho, Jong M

2010-01-01

Abstract Ketones have previously shown beneficial effects in models of neurodegenerative disorders, particularly against associated mitochondrial dysfunction and cognitive impairment. However, evidence of a synaptic protective effect of ketones remains lacking. We tested the effects of ketones on synaptic impairment induced by mitochondrial respiratory complex (MRC) inhibitors using electrophysiological, reactive oxygen species (ROS) imaging and biochemical techniques. MRC inhibitors dose-dependently suppressed both population spike (PS) and field potential amplitudes in the CA1 hippocampus. Pre-treatment with ketones strongly prevented changes in the PS, whereas partial protection was seen in the field potential. Rotenone (Rot; 100 nmol/L), a MRC I inhibitor, suppressed synaptic function without altering ROS levels and PS depression by Rot was unaffected by antioxidants. In contrast, antioxidant-induced PS recovery against the MRC II inhibitor 3-nitropropionic acid (3-NP; 1 mmol/L) was similar to the synaptic protective effects of ketones. Ketones also suppressed ROS generation induced by 3-NP. Finally, ketones reversed the decreases in ATP levels caused by Rot and 3-NP. In summary, our data demonstrate that ketones can preserve synaptic function in CA1 hippocampus induced by MRC dysfunction, likely through an antioxidant action and enhanced ATP generation. PMID:20374433

Dietary resveratrol confers apoptotic resistance to oxidative stress in myoblasts.

PubMed

Haramizu, Satoshi; Asano, Shinichi; Butler, David C; Stanton, David A; Hajira, Ameena; Mohamed, Junaith S; Alway, Stephen E

2017-12-01

High levels of reactive oxygen species (ROS) contribute to muscle cell death in aging and disuse. We have previously found that resveratrol can reduce oxidative stress in response to aging and hindlimb unloading in rodents in vivo, but it was not known if resveratrol would protect muscle stem cells during repair or regeneration when oxidative stress is high. To test the protective role of resveratrol on muscle stem cells directly, we treated the C2C12 mouse myoblast cell line with moderate (100 μM) or very high (1 mM) levels of H 2 O 2 in the presence or absence of resveratrol. The p21 promoter activity declined in myoblasts in response to high ROS, and this was accompanied a greater nuclear to cytoplasmic translocation of p21 in a dose-dependent matter in myoblasts as compared to myotubes. Apoptosis, as indicated by TdT-mediated dUTP nick-end labeling, was greater in C2C12 myoblasts as compared to myotubes (P<.05) after treatment with H 2 O 2 . Caspase-9, -8 and -3 activities were elevated significantly (P<.05) in myoblasts treated with H 2 O 2 . Myoblasts were more susceptible to ROS-induced oxidative stress than myotubes. We treated C2C12 myoblasts with 50 μM of resveratrol for periods up to 48 h to determine if myoblasts could be rescued from high-ROS-induced apoptosis by resveratrol. Resveratrol reduced the apoptotic index and significantly reduced the ROS-induced caspase-9, -8 and -3 activity in myoblasts. Furthermore, Bcl-2 and the Bax/Bcl-2 ratio were partially rescued in myoblasts by resveratrol treatment. Similarly, muscle stem cells isolated from mouse skeletal muscles showed reduced Sirt1 protein abundance with H 2 O 2 treatment, but this could be reversed by resveratrol. Reduced apoptotic susceptibility in myoblasts as compared to myotubes to ROS is regulated, at least in part, by enhanced p21 promoter activity and nuclear p21 location in myotubes. Resveratrol confers further protection against ROS by improving Sirt1 levels and increasing antioxidant production, which reduces mitochondrial associated apoptotic signaling, and cell death in myoblasts. Copyright © 2017 Elsevier Inc. All rights reserved.

Genomic evidence of reactive oxygen species elevation in papillary thyroid carcinoma with Hashimoto thyroiditis.

PubMed

Yi, Jin Wook; Park, Ji Yeon; Sung, Ji-Youn; Kwak, Sang Hyuk; Yu, Jihan; Chang, Ji Hyun; Kim, Jo-Heon; Ha, Sang Yun; Paik, Eun Kyung; Lee, Woo Seung; Kim, Su-Jin; Lee, Kyu Eun; Kim, Ju Han

2015-01-01

Elevated levels of reactive oxygen species (ROS) have been proposed as a risk factor for the development of papillary thyroid carcinoma (PTC) in patients with Hashimoto thyroiditis (HT). However, it has yet to be proven that the total levels of ROS are sufficiently increased to contribute to carcinogenesis. We hypothesized that if the ROS levels were increased in HT, ROS-related genes would also be differently expressed in PTC with HT. To find differentially expressed genes (DEGs) we analyzed data from the Cancer Genomic Atlas, gene expression data from RNA sequencing: 33 from normal thyroid tissue, 232 from PTC without HT, and 60 from PTC with HT. We prepared 402 ROS-related genes from three gene sets by genomic database searching. We also analyzed a public microarray data to validate our results. Thirty-three ROS related genes were up-regulated in PTC with HT, whereas there were only nine genes in PTC without HT (Chi-square p-value < 0.001). Mean log2 fold changes of up-regulated genes was 0.562 in HT group and 0.252 in PTC without HT group (t-test p-value = 0.001). In microarray data analysis, 12 of 32 ROS-related genes showed the same differential expression pattern with statistical significance. In gene ontology analysis, up-regulated ROS-related genes were related with ROS metabolism and apoptosis. Immune function-related and carcinogenesis-related gene sets were enriched only in HT group in Gene Set Enrichment Analysis. Our results suggested that ROS levels may be increased in PTC with HT. Increased levels of ROS may contribute to PTC development in patients with HT.

Zinc and calcium alter the relationship between mitochondrial respiration, ROS and membrane potential in rainbow trout (Oncorhynchus mykiss) liver mitochondria.

PubMed

Sharaf, Mahmoud S; Stevens, Don; Kamunde, Collins

2017-08-01

At excess levels, zinc (Zn) disrupts mitochondrial functional integrity and induces oxidative stress in aquatic organisms. Although much is known about the modulation of Zn toxicity by calcium (Ca) in fish, their interactions at the mitochondrial level have scarcely been investigated. Here we assessed the individual and combined effects of Zn and Ca on the relationship between mitochondrial respiration, ROS and membrane potential (ΔΨ mt ) in rainbow trout liver mitochondria. We tested if cation uptake through the mitochondrial calcium uniporter (MCU) is a prerequisite for Zn- and/or Ca-induced alteration of mitochondrial function. Furthermore, using our recently developed real-time multi-parametric method, we investigated the changes in respiration, ΔΨ mt , and reactive oxygen species (ROS, as hydrogen peroxide (H 2 O 2 )) release associated with Ca-induced mitochondrial depolarization imposed by transient and permanent openings of the mitochondrial permeability transition pore (mPTP). We found that independent of the MCU, Zn precipitated an immediate depolarization of the ΔΨ mt that was associated with relatively slow enhancement of H 2 O 2 release, inhibition of respiration and reversal of the positive correlation between ROS and ΔΨ mt . In contrast, an equitoxic dose of Ca caused transient depolarization, and stimulation of both respiration and H 2 O 2 release, effects that were completely abolished when the MCU was blocked. Contrary to our expectation that mitochondrial transition ROS Spike (mTRS) would be sensitive to both Zn and Ca, only Ca suppressed it. Moreover, Zn and Ca in combination immediately depolarized the ΔΨ mt , and caused transient and sustained stimulation of respiration and H 2 O 2 release, respectively. Lastly, we uncovered and characterized an mPTP-independent Ca-induced depolarization spike that was associated with exposure to moderately elevated levels of Ca. Importantly, we showed the stimulation of ROS release associated with highly elevated but not unrealistic Ca loads was not the cause but a result of mPTP opening in the high conductance mode. Copyright © 2017 Elsevier B.V. All rights reserved.

Effect of CoQ homologues on reactive oxygen generation by mitochondria.

PubMed

Imada, Isuke; Sato, Eisuke F; Kira, Yukimi; Inoue, Masayasu

2008-01-01

Effect of CoQ compounds (Qs) on reactive oxygen (ROS) generation by mitochondrial complex I was studied using rat liver mitochondria and chemiluminescence probe L012. Kinetic analysis revealed that short chain Qs, such as Q2 and idebenone enhanced ROS generation by mitochondrial NADH oxidase system by a succinate-inhibitable mechanism. Lipid peroxidation in mitochondrial membranes induced by NADH and iron was inhibited by short chain Qs. The inhibitory activity was enhanced by co-oxidation of succinate as determined by chemiluminescence method and by electron spin resonance spectroscopy. These results suggested that the reduced form of short chain Qs inhibited mitochondrial ROS generation and lipid peroxidation.

Abrus agglutinin promotes irreparable DNA damage by triggering ROS generation followed by ATM-p73 mediated apoptosis in oral squamous cell carcinoma.

PubMed

Sinha, Niharika; Panda, Prashanta K; Naik, Prajna P; Das, Durgesh N; Mukhopadhyay, Subhadip; Maiti, Tapas K; Shanmugam, Muthu K; Chinnathambi, Arunachalam; Zayed, M E; Alharbi, Sulaiman A; Sethi, Gautam; Agarwal, Rajesh; Bhutia, Sujit K

2017-11-01

Oral cancer, a type of head and neck cancer, is ranked as one of the top most malignancies in India. Herein, we evaluated the anticancer efficacy of Abrus agglutinin (AGG), a plant lectin, in oral squamous cell carcinoma. AGG selectively inhibited cell growth, and caused cell cycle arrest and mitochondrial apoptosis through a reactive oxygen species (ROS)-mediated ATM-p73 dependent pathway in FaDu cells. AGG-induced ROS accumulation was identified as the major mechanism regulating apoptosis, DNA damage and DNA-damage response, which were significantly reversed by ROS scavenger N-acetylcysteine (NAC). Moreover, AGG was found to interact with mitochondrial manganese-dependent superoxide dismutase that might inhibit its activity and increase ROS in FaDu cells. In oral cancer p53 is mutated, thus we focused on p73; AGG resulted in p73 upregulation and knock down of p73 caused a decrease in AGG-induced apoptosis. Interestingly, AGG-dependent p73 expression was found to be regulated by ROS, which was reversed by NAC treatment. A reduction in the level of p73 in AGG-treated shATM cells was found to be associated with a decreased apoptosis. Moreover, administration of AGG (50 μg/kg body weight) significantly inhibited the growth of FaDu xenografts in athymic nude mice. In immunohistochemical analysis, the xenografts from AGG-treated mice displayed a decrease in PCNA expression and an increase in caspase-3 activation as compared to the controls. In conclusion, we established a connection among ROS, ATM and p73 in AGG-induced apoptosis, which might be useful in enhancing the therapeutic targeting of p53 deficient oral squamous cell carcinoma. © 2017 Wiley Periodicals, Inc.

Hexavalent chromium targets mitochondrial respiratory chain complex I to induce reactive oxygen species-dependent caspase-3 activation in L-02 hepatocytes.

PubMed

Xiao, Fang; Li, Yanhong; Dai, Lu; Deng, Yuanyuan; Zou, Yue; Li, Peng; Yang, Yuan; Zhong, Caigao

2012-09-01

Hexavalent chromium [Cr(VI)], which is used for various industrial applications, such as leather tanning and chroming, can cause a number of human diseases including inflammation and cancer. Cr(VI) exposure leads to severe damage to the liver, but the mechanisms involved in Cr(VI)-mediated toxicity in the liver are unclear. The present study provides evidence that Cr(VI) enhances reactive oxygen species (ROS) accumulation by inhibiting the mitochondrial respiratory chain complex (MRCC) I. Cr(VI) did not affect the expression levels of antioxidative proteins such as superoxide dismutase (SOD), catalase and thioredoxin (Trx), indicating that the antioxidative system was not involved in Cr(VI)-induced ROS accumulation. We found that ROS mediated caspase-3 activation partially depends on the downregulation of the heat shock protein (HSP) 70 and 90. In order to confirm our hypothesis that ROS plays a key role in Cr(VI)-mediated cytotoxicity, we used N-acetylcysteine (NAC) to inhibit the accumulation of ROS. NAC successfully blocked the inhibition of HSP70 and HSP90 as well as the activation of caspase-3, suggesting that ROS is essential in Cr(VI)-induced caspase-3 activation. By applying different MRCC substrates as electron donors, we also confirmed that Cr(VI) could accept the electrons leaked from MRCC I and the reduction occurs at MRCC I. In conclusion, the present study demonstrates that Cr(VI) induces ROS-dependent caspase-3 activation by inhibiting MRCC I activity, and MRCC I has been identified as a new target and a new mechanism for the apoptosis-inducing activity displayed by Cr(VI).

Metabolic syndrome enhances endoplasmic reticulum, oxidative stress and leukocyte-endothelium interactions in PCOS.

PubMed

Bañuls, Celia; Rovira-Llopis, Susana; Martinez de Marañon, Aranzazu; Veses, Silvia; Jover, Ana; Gomez, Marcelino; Rocha, Milagros; Hernandez-Mijares, Antonio; Victor, Victor M

2017-06-01

Polycystic ovary syndrome (PCOS) is associated with insulin resistance, which can lead to metabolic syndrome (MetS). Oxidative stress and leukocyte-endothelium interactions are related to PCOS. Our aim was to evaluate whether the presence of MetS in PCOS patients can influence endoplasmic reticulum (ER) and oxidative stress and leukocyte-endothelium interactions. This was a prospective controlled study conducted in an academic medical center. The study population consisted of 148 PCOS women (116 without/32 with MetS) and 112 control subjects (87 without / 25 with MetS). Metabolic parameters, reactive oxygen species (ROS) production, ER stress markers (GRP78, sXBP1, ATF6), leukocyte-endothelium interactions, adhesion molecules (VCAM-1, ICAM-1, E-Selectin), TNF-α and IL-6 were determined. Total ROS, inflammatory parameters and adhesion molecules were enhanced in the presence of MetS (p<0.05), and the PCOS+MetS group showed higher levels of IL-6 and ICAM-1 than controls (p<0.05). Increased adhesion and leukocyte rolling flux were observed in PCOS and PCOS+MetS groups vs their respective controls (p<0.05). GRP78 protein expression was higher in the PCOS groups (p<0.05 vs controls) and sXBP1 was associated with the presence of MetS (p<0.05 vs controls without MetS). Furthermore, PCOS+MetS patients exhibited higher GRP78 and ATF6 levels than controls and PCOS patients without MetS (p<0.05). In PCOS women, HOMA-IR was positively correlated with ICAM-1 (r=0.501; p<0.01), ROS (r=0.604; p<0.01), rolling flux (r=0.455;p<0.05) and GRP78 (r=0.574; p<0.001). Our findings support the hypothesis of an association between altered metabolic status, increased ROS production, ER stress and leukocyte-endothelium interactions in PCOS, all of which are related to vascular complications. Copyright © 2017 Elsevier Inc. All rights reserved.

Reactive Oxygen Species Function to Mediate the Fe Deficiency Response in an Fe-Efficient Apple Genotype: An Early Response Mechanism for Enhancing Reactive Oxygen Production.

PubMed

Sun, Chaohua; Wu, Ting; Zhai, Longmei; Li, Duyue; Zhang, Xinzhong; Xu, Xuefeng; Ma, Huiqin; Wang, Yi; Han, Zhenhai

2016-01-01

Reactive oxygen species (ROS) are important signaling molecules in plants that contribute to stress acclimation. This study demonstrated that ROS play a critical role in Fe deficiency-induced signaling at an early stage in Malus xiaojinensis . Once ROS production has been initiated, prolonged Fe starvation leads to activation of ROS scavenging mechanisms. Further, we demonstrated that ROS scavengers are involved in maintaining the cellular redox homeostasis during prolonged Fe deficiency treatment. Taken together, our results describe a feedback repression loop for ROS to preserve redox homeostasis and maintain a continuous Fe deficiency response in the Fe-efficient woody plant M. xiaojinensis . More broadly, this study reveals a new mechanism in which ROS mediate both positive and negative regulation of plant responses to Fe deficiency stress.

Multifunctional nanoplatform for enhanced photodynamic cancer therapy and magnetic resonance imaging.

PubMed

Hao, Yongwei; Zhang, Bingxiang; Zheng, Cuixia; Niu, Mengya; Guo, Haochen; Zhang, Hongling; Chang, Junbiao; Zhang, Zhenzhong; Wang, Lei; Zhang, Yun

2017-03-01

Co-delivery of photosensitizers and synergistic agents by one single nanoplatform is interesting for enhancing photodynamic therapy (PDT) of cancer. Here, a multifunctional nanoplatform for enhanced photodynamic therapy and magnetic resonance imaging of cancer was constructed. The poly (lactide-co-glycolide) (PLGA) nanoparticles (NPs) loaded with hematoporphyrin monomethyl ether (HMME) were coated with multifunctional manganese dioxide (MnO 2 ) shells, which were designed as PLGA/HMME@MnO 2 NPs. Once the NPs were effectively taken up by tumor cells, the intracellular H 2 O 2 was catalysed by the MnO 2 shells to generate O 2 . Meanwhile, the higher glutathione (GSH) promoted the degradation of MnO 2 into Mn 2+ ions with the ability of magnetic resonance (MR) imaging. After the degradation of outer layer, the release of photosensitizer was promoted. Under irradiation, the released HMME produced cytotoxic reactive oxygen species (ROS) to damage the tumor cells when the O 2 was generated in the hypoxic tumor site. Furthermore, the decreased GSH level further inhibited the consumption of the produced ROS, which greatly enhanced the PDT efficacy. Therefore, this study suggested that this multifunctional system has the potential for enhanced photodynamic therapy and magnetic resonance imaging. Copyright © 2016 Elsevier B.V. All rights reserved.

Hypericin-mediated sonodynamic therapy induces autophagy and decreases lipids in THP-1 macrophage by promoting ROS-dependent nuclear translocation of TFEB.

PubMed

Li, Xuesong; Zhang, Xin; Zheng, Longbin; Kou, Jiayuan; Zhong, Zhaoyu; Jiang, Yueqing; Wang, Wei; Dong, Zengxiang; Liu, Zhongni; Han, Xiaobo; Li, Jing; Tian, Ye; Zhao, Yajun; Yang, Liming

2016-12-22

Lipid catabolism disorder is the primary cause of atherosclerosis. Transcription factor EB (TFEB) prevents atherosclerosis by activating macrophage autophagy to promote lipid degradation. Hypericin-mediated sonodynamic therapy (HY-SDT) has been proved non-invasively inducing THP-1-derived macrophage apoptosis; however, it is unknown whether macrophage autophagy could be triggered by HY-SDT to influence cellular lipid catabolism via regulating TFEB. Here, we report that HY-SDT resulted in the time-dependent THP-1-derived macrophage autophagy activation through AMPK/AKT/mTOR pathway. Besides, TFEB nuclear translocation in macrophage was triggered by HY-SDT to promote autophagy activation and lysosome regeneration which enhanced lipid degradation in response to atherogenic lipid stressors. Moreover, following HY-SDT, the ABCA1 expression level was increased to promote lipid efflux in macrophage, and the expression levels of CD36 and SR-A were decreased to inhibit lipid uptake, both of which were prevented by TFEB knockdown. These results indicated that TFEB nuclear translocation activated by HY-SDT was not only the key regulator of autophagy activation and lysosome regeneration in macrophage to promote lipolysis, but also had a crucial role in reverse cholesterol transporters to decrease lipid uptake and increase lipid efflux. Reactive oxygen species (ROS) were adequately generated in macrophage by HY-SDT. Further, ROS scavenger N-acetyl-l-cysteine abolished HY-SDT-induced TFEB nuclear translocation and autophagy activation, implying that ROS were the primary upstream factors responsible for these effects during HY-SDT. In summary, our data indicate that HY-SDT decreases lipid content in macrophage by promoting ROS-dependent nuclear translocation of TFEB to influence consequent autophagy activation and cholesterol transporters. Thus, HY-SDT may be beneficial for atherosclerosis via TFEB regulation to ameliorate lipid overload in atherosclerotic plaques.

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

Kwak, Geun-Hee; Kim, Ki Young; Kim, Hwa-Young, E-mail: hykim@ynu.ac.kr

Methionine sulfoxide reductase B3 (MsrB3), which is primarily found in the endoplasmic reticulum (ER), is an important protein repair enzyme that stereospecifically reduces methionine-R-sulfoxide residues. We previously found that MsrB3 deficiency arrests the cell cycle at the G{sub 1}/S stage through up-regulation of p21 and p27. In this study, we report a critical role of MsrB3 in gene expression of heme oxygenase-1 (HO-1), which has an anti-proliferative effect associated with p21 up-regulation. Depletion of MsrB3 elevated HO-1 expression in mammalian cells, whereas MsrB3 overexpression had no effect. MsrB3 deficiency increased cellular reactive oxygen species (ROS), particularly in the mitochondria. ERmore » stress, which is associated with up-regulation of HO-1, was also induced by depletion of MsrB3. Treatment with N-acetylcysteine as an ROS scavenger reduced augmented HO-1 levels in MsrB3-depleted cells. MsrB3 deficiency activated Nrf2 transcription factor by enhancing its expression and nuclear import. The activation of Nrf2 induced by MsrB3 depletion was confirmed by increased expression levels of its other target genes, such as γ-glutamylcysteine ligase. Taken together, these data suggest that MsrB3 attenuates HO-1 induction by inhibiting ROS production, ER stress, and Nrf2 activation. -- Highlights: •MsrB3 depletion induces HO-1 expression. •MsrB3 deficiency increases cellular ROS and ER stress. •MsrB3 deficiency activates Nrf2 by increasing its expression and nuclear import. •MsrB3 attenuates HO-1 induction by inhibiting ROS production and Nrf2 activation.« less

CD44 variant-dependent redox status regulation in liver fluke-associated cholangiocarcinoma: A target for cholangiocarcinoma treatment.

PubMed

Thanee, Malinee; Loilome, Watcharin; Techasen, Anchalee; Sugihara, Eiji; Okazaki, Shogo; Abe, Shinya; Ueda, Shiho; Masuko, Takashi; Namwat, Nisana; Khuntikeo, Narong; Titapun, Attapol; Pairojkul, Chawalit; Saya, Hideyuki; Yongvanit, Puangrat

2016-07-01

Expression of CD44, especially the variant isoforms (CD44v) of this major cancer stem cell marker, contributes to reactive oxygen species (ROS) defense through stabilizing xCT (a cystine-glutamate transporter) and promoting glutathione synthesis. This enhances cancer development and increases chemotherapy resistance. We investigate the role of CD44v in the regulation of the ROS defense system in cholangiocarcinoma (CCA). Immunohistochemical staining of CD44v and p38(MAPK) (a major ROS target) expression in Opisthorchis viverrini-induced hamster CCA tissues (at 60, 90, 120, and 180 days) reveals a decreased phospho-p38(MAPK) signal, whereas the CD44v signal was increased during bile duct transformation. Patients with CCA showed CD44v overexpression and negative-phospho-p38(MAPK) patients a significantly shorter survival rate than the low CD44v signal and positive-phospho-p38(MAPK) patients (P = 0.030). Knockdown of CD44 showed that xCT and glutathione levels were decreased, leading to a high level of ROS. We examined xCT-targeted CD44v cancer stem cell therapy using sulfasalazine. Glutathione decreased and ROS increased after the treatment, leading to inhibition of cell proliferation and induction of cell death. Thus, the accumulation of CD44v leads to the suppression of p38(MAPK) in transforming bile duct cells. The redox status regulation of CCA cells depends on the expression of CD44v to contribute the xCT function and is a link to the poor prognosis of patients. Thus, an xCT inhibitor could inhibit cell growth and activate cell death. This suggests that an xCT-targeting drug may improve CCA therapy by sensitization to the available drug (e.g. gemcitabine) by blocking the mechanism of the cell's ROS defensive system. © 2016 The Authors. Cancer Science published by John Wiley & Sons Australia, Ltd on behalf of Japanese Cancer Association.

Synergistic antitumor activity of rapamycin and EF24 via increasing ROS for the treatment of gastric cancer.

PubMed

Chen, Weiqian; Zou, Peng; Zhao, Zhongwei; Chen, Xi; Fan, Xiaoxi; Vinothkumar, Rajamanickam; Cui, Ri; Wu, Fazong; Zhang, Qianqian; Liang, Guang; Ji, Jiansong

2016-12-01

Mechanistic/mammalian target of rapamycin (mTOR) has emerged as a new potential therapeutic target for gastric cancer. Rapamycin and rapamycin analogs are undergoing clinical trials and have produced clinical responses in a subgroup of cancer patients. However, monotherapy with rapamycin at safe dosage fails to induce cell apoptosis and tumor regression which has hampered its clinical application. This has led to the exploration of more effective combinatorial regimens to enhance the effectiveness of rapamycin. In our present study, we have investigated the combination of rapamycin and a reactive oxygen species (ROS) inducer EF24 in gastric cancer. We show that rapamycin increases intracellular ROS levels and displays selective synergistic antitumor activity with EF24 in gastric cancer cells. This activity was mediated through the activation of c-Jun N terminal kinase and endoplasmic reticulum stress (ER) pathways in cancer cells. We also show that inhibiting ROS accumulation reverses ER stress and prevents apoptosis induced by the combination of rapamycin and EF24. These mechanisms were confirmed using human gastric cancer xenografts in immunodeficient mice. Taken together, our work provides a novel therapeutic strategy for the treatment of gastric cancer. The work reveals that ROS generation could be an important target for the development of new combination therapies for cancer treatment. Copyright © 2016 The Authors. Published by Elsevier B.V. All rights reserved.

Low-level laser therapy (LLLT) reduces oxidative stress in primary cortical neurons in vitro.

PubMed

Huang, Ying-Ying; Nagata, Kazuya; Tedford, Clark E; McCarthy, Thomas; Hamblin, Michael R

2013-10-01

Low-level laser (light) therapy (LLLT) involves absorption of photons being in the mitochondria of cells leading to improvement in electron transport, increased mitochondrial membrane potential (MMP), and greater ATP production. Low levels of reactive oxygen species (ROS) are produced by LLLT in normal cells that are beneficial. We exposed primary cultured murine cortical neurons to oxidative stressors: hydrogen peroxide, cobalt chloride and rotenone in the presence or absence of LLLT (3 J/cm², CW, 810 nm wavelength laser, 20 mW/cm²). Cell viability was determined by Prestoblue™ assay. ROS in mitochondria was detected using Mito-sox, while ROS in cytoplasm was detected with CellRox™. MMP was measured with tetramethylrhodamine. In normal neurons LLLT elevated MMP and increased ROS. In oxidatively-stressed cells LLLT increased MMP but reduced high ROS levels and protected cultured cortical neurons from death. Although LLLT increases ROS in normal neurons, it reduces ROS in oxidatively-stressed neurons. In both cases MMP is increased. These data may explain how LLLT can reduce clinical oxidative stress in various lesions while increasing ROS in cells in vitro. Copyright © 2013 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Metformin induces oxidative stress in white adipocytes and raises uncoupling protein 2 levels.

PubMed

Anedda, Andrea; Rial, Eduardo; González-Barroso, M Mar

2008-10-01

Metformin is a drug widely used to treat type 2 diabetes. It enhances insulin sensitivity by improving glucose utilization in tissues like liver or muscle. Metformin inhibits respiration, and the decrease in cellular energy activates the AMP-activated protein kinase that in turn switches on catabolic pathways. Moreover, metformin increases lipolysis and beta-oxidation in white adipose tissue, thereby reducing the triglyceride stores. The uncoupling proteins (UCPs) are transporters that lower the efficiency of mitochondrial oxidative phosphorylation. UCP2 is thought to protect against oxidative stress although, alternatively, it could play an energy dissipation role. The aim of this work was to analyse the involvement of UCP2 on the effects of metformin in white adipocytes. We studied the effect of this drug in differentiating 3T3-L1 adipocytes and found that metformin causes oxidative stress since it increases the levels of reactive oxygen species (ROS) and lowers the aconitase activity. Variations in UCP2 protein levels parallel those of ROS. Metformin also increases lipolysis in these cells although only when the levels of ROS and UCP2 have decreased. Hence, UCP2 does not appear to be needed to facilitate fatty acid oxidation. Furthermore, treatment of C57BL/6 mice with metformin also augmented the levels of UCP2 in epididymal white adipose tissue. We conclude that metformin treatment leads to the overexpression of UCP2 in adipocytes to minimize the oxidative stress that is probably due to the inhibition of respiration caused by the drug.

Loss of Sirt1 Promotes Prostatic Intraepithelial Neoplasia, Reduces Mitophagy, and Delays Park2 Translocation to Mitochondria

PubMed Central

Di Sante, Gabriele; Pestell, Timothy G.; Casimiro, Mathew C.; Bisetto, Sara; Powell, Michael J.; Lisanti, Michael P.; Cordon-Cardo, Carlos; Castillo-Martin, Mireia; Bonal, Dennis M.; Debattisti, Valentina; Chen, Ke; Wang, Liping; He, Xiaohong; McBurney, Michael W.; Pestell, Richard G.

2016-01-01

Prostatic intraepithelial neoplasia is a precursor to prostate cancer. Herein, deletion of the NAD+-dependent histone deacetylase Sirt1 induced histological features of prostatic intraepithelial neoplasia at 7 months of age; these features were associated with increased cell proliferation and enhanced mitophagy. In human prostate cancer, lower Sirt1 expression in the luminal epithelium was associated with poor prognosis. Genetic deletion of Sirt1 increased mitochondrial superoxide dismutase 2 (Sod2) acetylation of lysine residue 68, thereby enhancing reactive oxygen species (ROS) production and reducing SOD2 activity. The PARK2 gene, which has several features of a tumor suppressor, encodes an E3 ubiquitin ligase that participates in removal of damaged mitochondria via mitophagy. Increased ROS in Sirt1−/− cells enhanced the recruitment of Park2 to the mitochondria, inducing mitophagy. Sirt1 restoration inhibited PARK2 translocation and ROS production requiring the Sirt1 catalytic domain. Thus, the NAD+-dependent inhibition of SOD2 activity and ROS by SIRT1 provides a gatekeeper function to reduce PARK2-mediated mitophagy and aberrant cell survival. PMID:25529796

Feedback regulation via AMPK and HIF-1 mediates ROS-dependent longevity in Caenorhabditis elegans

PubMed Central

Hwang, Ara B.; Ryu, Eun-A; Artan, Murat; Chang, Hsin-Wen; Kabir, Mohammad Humayun; Nam, Hyun-Jun; Lee, Dongyeop; Yang, Jae-Seong; Kim, Sanguk; Mair, William B.; Lee, Cheolju; Lee, Siu Sylvia; Lee, Seung-Jae

2014-01-01

Mild inhibition of mitochondrial respiration extends the lifespan of many species. In Caenorhabditis elegans, reactive oxygen species (ROS) promote longevity by activating hypoxia-inducible factor 1 (HIF-1) in response to reduced mitochondrial respiration. However, the physiological role and mechanism of ROS-induced longevity are poorly understood. Here, we show that a modest increase in ROS increases the immunity and lifespan of C. elegans through feedback regulation by HIF-1 and AMP-activated protein kinase (AMPK). We found that activation of AMPK as well as HIF-1 mediates the longevity response to ROS. We further showed that AMPK reduces internal levels of ROS, whereas HIF-1 amplifies the levels of internal ROS under conditions that increase ROS. Moreover, mitochondrial ROS increase resistance to various pathogenic bacteria, suggesting a possible association between immunity and long lifespan. Thus, AMPK and HIF-1 may control immunity and longevity tightly by acting as feedback regulators of ROS. PMID:25288734

NtLTP4, a lipid transfer protein that enhances salt and drought stresses tolerance in Nicotiana tabacum.

PubMed

Xu, Yang; Zheng, Xinxin; Song, Yunzhi; Zhu, Lifei; Yu, Zipeng; Gan, Liming; Zhou, Shumei; Liu, Hongmei; Wen, Fujiang; Zhu, Changxiang

2018-06-11

Lipid transfer proteins (LTPs), a class of small, ubiquitous proteins, play critical roles in various environmental stresses. However, their precise biological functions remain unknown. Here we isolated an extracellular matrix-localised LTP, NtLTP4, from Nicotiana tabacum. The overexpression of NtLTP4 in N. tabacum enhanced resistance to salt and drought stresses. Upon exposure to high salinity, NtLTP4-overexpressing lines (OE lines) accumulated low Na + levels. Salt-responsive genes, including Na + /H + exchangers (NHX1) and high-affinity K + transporter1 (HKT1), were dramatically higher in OE lines than in wild-type lines. NtLTP4 might regulate transcription levels of NHX1 and HKT1 to alleviate the toxicity of Na + . Interestingly, OE lines enhanced the tolerance of N. tabacum to drought stress by reducing the transpiration rate. Moreover, NtLTP4 could increase reactive oxygen species (ROS)-scavenging enzyme activity and expression levels to scavenge excess ROS under drought and high salinity conditions. We used a two-hybrid yeast system and screened seven putative proteins that interact with NtLTP4 in tobacco. An MAPK member, wound-induced protein kinase, was confirmed to interact with NtLTP4 via co-immunoprecipitation and a firefly luciferase complementation imaging assay. Taken together, this is the first functional analysis of NtLTP4, and proves that NtLTP4 positively regulates salt and drought stresses in N. tabacum.

Anti-apoptotic effect of esculin on dopamine-induced cytotoxicity in the human neuroblastoma SH-SY5Y cell line.

PubMed

Zhao, Da-Long; Zou, Li-Bo; Lin, Sheng; Shi, Jian-Gong; Zhu, Hai-Bo

2007-11-01

Dopamine (DA), as a neurotoxin, can elicit severe Parkinson's disease-like syndrome by elevating intracellular reactive oxygen species (ROS) levels and apoptotic activity. In this study, we examined the effect of esculin, which was extracted from Fraxinus sielboldiana blume, on DA-induced cytotoxicity and the underlying mechanism in human neuroblastoma SH-SY5Y cells. Our results suggest that the protective effects of esculin (10(-7), 10(-6) and 10(-5) M) on DA-induced cytotoxicity may be ascribed to its anti-oxidative properties by reducing ROS level, and its anti-apoptotic effect via protecting mitochondrion membrane potential (DeltaPsim), enhancing superoxide dismutaese (SOD) activity and reduced glutathione (GSH) levels, and regulating P53, Bax and Bcl-2 expression. In addition, esculin inhibited the release of cytochrome c and apoptosis-inducing factor (AIF), and the protein expression of activated caspase 3. These data indicate that esculin may provide a useful therapeutic strategy for the treatment of progressive neurodegenerative diseases such as Parkinson's disease (PD).

Caloric Restriction-Induced Extension of Chronological Lifespan Requires Intact Respiration in Budding Yeast.

PubMed

Kwon, Young-Yon; Lee, Sung-Keun; Lee, Cheol-Koo

2017-04-01

Caloric restriction (CR) has been shown to extend lifespan and prevent cellular senescence in various species ranging from yeast to humans. Many effects of CR may contribute to extend lifespan. Specifically, CR prevents oxidative damage from reactive oxygen species (ROS) by enhancing mitochondrial function. In this study, we characterized 33 single electron transport chain (ETC) gene-deletion strains to identify CR-induced chronological lifespan (CLS) extension mechanisms. Interestingly, defects in 17 of these 33 ETC gene-deleted strains showed loss of both respiratory function and CR-induced CLS extension. On the contrary, the other 16 respiration-capable mutants showed increased CLS upon CR along with increased mitochondrial membrane potential (MMP) and intracellular adenosine triphosphate (ATP) levels, with decreased mitochondrial superoxide generation. We measured the same parameters in the 17 non-respiratory mutants upon CR. CR simultaneously increased MMP and mitochondrial superoxide generation without altering intracellular ATP levels. In conclusion, respiration is essential for CLS extension by CR and is important for balancing MMP, ROS, and ATP levels.

Lead tolerance in plants: strategies for phytoremediation.

PubMed

Gupta, D K; Huang, H G; Corpas, F J

2013-04-01

Lead (Pb) is naturally occurring element whose distribution in the environment occurs because of its extensive use in paints, petrol, explosives, sludge, and industrial wastes. In plants, Pb uptake and translocation occurs, causing toxic effects resulting in decrease of biomass production. Commonly plants may prevent the toxic effect of heavy metals by induction of various celular mechanisms such as adsorption to the cell wall, compartmentation in vacuoles, enhancement of the active efflux, or induction of higher levels of metal chelates like a protein complex (metallothioneins and phytochelatins), organic (citrates), and inorganic (sulphides) complexes. Phyotochelains (PC) are synthesized from glutathione (GSH) and such synthesis is due to transpeptidation of γ-glutamyl cysteinyl dipeptides from GSH by the action of a constitutively present enzyme, PC synthase. Phytochelatin binds to Pb ions leading to sequestration of Pb ions in plants and thus serves as an important component of the detoxification mechanism in plants. At cellular level, Pb induces accumulation of reactive oxygen species (ROS), as a result of imbalanced ROS production and ROS scavenging processes by imposing oxidative stress. ROS include superoxide radical (O2(.-)), hydrogen peroxide (H2O2) and hydroxyl radical ((·)OH), which are necessary for the correct functioning of plants; however, in excess they caused damage to biomolecules, such as membrane lipids, proteins, and nucleic acids among others. To limit the detrimental impact of Pb, efficient strategies like phytoremediation are required. In this review, it will discuss recent advancement and potential application of plants for lead removal from the environment.

Effect of excess iron on oxidative stress and gluconeogenesis through hepcidin during mitochondrial dysfunction.

PubMed

Lee, Hyo Jung; Choi, Joo Sun; Lee, Hye Ja; Kim, Won-Ho; Park, Sang Ick; Song, Jihyun

2015-12-01

Excessive tissue iron levels are a risk factor for insulin resistance and type 2 diabetes, which are associated with alterations in iron metabolism. However, the mechanisms underlying this association are not well understood. This study used human liver SK-HEP-1 cells to examine how excess iron induces mitochondrial dysfunction and how hepcidin controls gluconeogenesis. Excess levels of reactive oxygen species (ROS) and accumulated iron due to iron overload induced mitochondrial dysfunction, leading to a decrease in cellular adenosine triphosphate content and cytochrome c oxidase III expression, with an associated increase in gluconeogenesis. Disturbances in mitochondrial function caused excess iron deposition and unbalanced expression of iron metabolism-related proteins such as hepcidin, ferritin H and ferroportin during the activation of p38 mitogen-activated protein kinase (MAPK) and CCAAT/enhancer-binding protein alpha (C/EBPα), which are responsible for increased phosphoenolpyruvate carboxykinase expression. Desferoxamine and n-acetylcysteine ameliorated these deteriorations by inhibiting p38 MAPK and C/EBPα activity through iron chelation and ROS scavenging activity. Based on experiments using hepcidin shRNA and hepcidin overexpression, the activation of hepcidin affects ROS generation and iron deposition, which disturbs mitochondrial function and causes an imbalance in iron metabolism and increased gluconeogenesis. Repression of hepcidin activity can reverse these changes. Our results demonstrate that iron overload is associated with mitochondrial dysfunction and that together they can cause abnormal hepatic gluconeogenesis. Hepcidin expression may modulate this disorder by regulating ROS generation and iron deposition. Copyright © 2015 Elsevier Inc. All rights reserved.

Participation of reactive oxygen species in diabetes-induced endothelial dysfunction.

PubMed

Zúrová-Nedelcevová, Jana; Navarová, Jana; Drábiková, Katarína; Jancinová, Viera; Petríková, Margita; Bernátová, Iveta; Kristová, Viera; Snirc, Vladimír; Nosál'ová, Viera; Sotníková, Ruzena

2006-12-01

In the present study, the relationship between diabetes-induced hyperglycemia, reactive oxygen species production and endothelium-mediated arterial function was examined. The effect of antioxidant on the reactive oxygen species induced damage was tested. Diabetes was induced by streptozotocin (STZ), 3 x 30 mg/kg i.p., administered on three consecutive days. After 10 weeks of diabetes, the functional state of the endothelium of the aorta was tested, endothelemia evaluation was performed and systolic blood pressure was measured. Reactive oxygen species (ROS) formation in blood and the aorta was measured using luminol-enhanced chemiluminescence (CL). Levels of reduced glutathione (GSH) were determined in the aorta, kidney, and plasma. To study the involvement of hyperglycemia in functional impairment of the endothelium, aortal rings incubated in solution with high glucose concentration were tested in in vitro experiments. After 10 weeks of diabetes, endothelial injury was observed, exhibited by diminished endothelium-dependent relaxation of the aorta, increased endothelemia and by elevated systolic blood pressure. Using luminol-enhanced CL, a significant increase of ROS production was found in arterial tissue and blood. GSH levels were significantly increased in the kidney, while there were no GSH changes in plasma and the aorta. Incubation of aortic rings in solution with high glucose concentration led to impairment of endothelium-dependent relaxation. The synthetic antioxidant SMe1EC2 was able to restore reduced endothelium-mediated relaxation. Our results suggest an important role of hyperglycemia-induced ROS production in mediating endothelial dysfunction in experimental diabetes, confirmed by CL and the protective effect of the antioxidant SMe1EC2.

Iron overload promotes mitochondrial fragmentation in mesenchymal stromal cells from myelodysplastic syndrome patients through activation of the AMPK/MFF/Drp1 pathway.

PubMed

Zheng, Qingqing; Zhao, Youshan; Guo, Juan; Zhao, Sida; Fei, Chengming; Xiao, Chao; Wu, Dong; Wu, Lingyun; Li, Xiao; Chang, Chunkang

2018-05-03

Iron overload (IO) has been reported to contribute to mesenchymal stromal cell (MSC) damage, but the precise mechanism has yet to be clearly elucidated. In this study, we found that IO increased cell apoptosis and lowered cell viability in MSCs, accompanied by extensive mitochondrial fragmentation and autophagy enhancement. All these effects were reactive oxygen species (ROS) dependent. In MSCs with IO, the ATP concentrations were significantly reduced due to high ROS levels and low electron respiratory chain complex (ETC) II/III activity. Reduced ATP phosphorylated AMP-activated protein kinase (AMPK). Activation of AMPK kinase complexes triggered mitochondrial fission. Moreover, gene knockout of AMPK via CRISPR/Cas9 reduced cell apoptosis, enhanced cell viability and attenuated mitochondrial fragmentation and autophagy caused by IO in MSCs. Further, AMPK-induced mitochondrial fragmentation of MSCs with IO was mediated via phosphorylation of mitochondrial fission factor (MFF), a mitochondrial outer-membrane receptor for the GTPase dynamin-related protein 1 (Drp1). Gene knockdown of MFF reversed AMPK-induced mitochondrial fragmentation in MSCs with IO. In addition, MSCs from IO patients with myelodysplastic syndrome (MDS) showed increased cell apoptosis, decreased cell viability, higher ROS levels, lower ATP concentrations and increased mitochondrial fragmentation compared with MSCs from non-IO patients. In addition, iron chelation or antioxidant weakened the activity of the AMPK/MFF/Drp1 pathway in MDS-MSCs with IO from several patients, accompanied by attenuation of mitochondrial fragmentation and autophagy. Taken together, the AMPK/MFF/Drp1 pathway has an important role in the damage to MDS-MSCs caused by IO.

Decursin enhances TRAIL-induced apoptosis through oxidative stress mediated- endoplasmic reticulum stress signalling in non-small cell lung cancers.

PubMed

Kim, Jaekwang; Yun, Miyong; Kim, Eun-Ok; Jung, Deok-Beom; Won, Gunho; Kim, Bonglee; Jung, Ji Hoon; Kim, Sung-Hoon

2016-03-01

The TNF-related apoptosis-inducing ligand (TRAIL) is a promising anticancer agent due to its remarkable ability to selectively kill tumour cells. However, because most tumours exhibit resistance to TRAIL-induced apoptosis, the development of combination therapies to overcome resistance to TRAIL is required for effective cancer therapy. Cell viability and possible synergy between the plant pyranocoumarin decursin and TRAIL was measured by MTT assay and calcusyn software. Reactive oxygen species (ROS) and apoptosis were measured using dichlorodihydrofluorescein and annexin/propidium iodide in cell flow cytometry. Changes in protein levels were assessed with Western blotting. Combining decursin and TRAIL markedly decreased cell viability and increased apoptosis in TRAIL-resistant non-small-cell lung cancer (NSCLC) cell lines. Decursin induced expression of the death receptor 5 (DR5). Inhibition of DR5 attenuated apoptotic cell death in decursin + TRAIL treated NSCLC cell lines. Interestingly, induction of DR5 and CCAAT/enhancer-binding protein homologues protein by decursin was mediated through selective induction of the pancreatic endoplasmic reticulum kinase (PERK)/activating transcription factor 4 (ATF4) branch of the endoplasmic reticulum stress response pathway. Furthermore, enhancement of PERK/ATF4 signalling by decursin was mediated by ROS generation in NSCLC cell lines, but not in normal human lung cells. Decursin also markedly down-regulated expression of survivin and Bcl-xL in TRAIL-resistant NSCLC cells. ROS generation by decursin selectively activated the PERK/ATF4 axis of the endoplasmic reticulum stress signalling pathway, leading to enhanced TRAIL sensitivity in TRAIL-resistant NSCLC cell lines, partly via up-regulation of DR5. © 2015 The British Pharmacological Society.

Po2 cycling protects diaphragm function during reoxygenation via ROS, Akt, ERK, and mitochondrial channels.

PubMed

Zuo, Li; Pannell, Benjamin K; Re, Anthony T; Best, Thomas M; Wagner, Peter D

2015-12-01

Po2 cycling, often referred to as intermittent hypoxia, involves exposing tissues to brief cycles of low oxygen environments immediately followed by hyperoxic conditions. After experiencing long-term hypoxia, muscle can be damaged during the subsequent reintroduction of oxygen, which leads to muscle dysfunction via reperfusion injury. The protective effect and mechanism behind Po2 cycling in skeletal muscle during reoxygenation have yet to be fully elucidated. We hypothesize that Po2 cycling effectively increases muscle fatigue resistance through reactive oxygen species (ROS), protein kinase B (Akt), extracellular signal-regulated kinase (ERK), and certain mitochondrial channels during reoxygenation. Using a dihydrofluorescein fluorescent probe, we detected the production of ROS in mouse diaphragmatic skeletal muscle in real time under confocal microscopy. Muscles treated with Po2 cycling displayed significantly attenuated ROS levels (n = 5; P < 0.001) as well as enhanced force generation compared with controls during reperfusion (n = 7; P < 0.05). We also used inhibitors for signaling molecules or membrane channels such as ROS, Akt, ERK, as well as chemical stimulators to close mitochondrial ATP-sensitive potassium channel (KATP) or open mitochondrial permeability transition pore (mPTP). All these blockers or stimulators abolished improved muscle function with Po2 cycling treatment. This current investigation has discovered a correlation between KATP and mPTP and the Po2 cycling pathway in diaphragmatic skeletal muscle. Thus we have identified a unique signaling pathway that may involve ROS, Akt, ERK, and mitochondrial channels responsible for Po2 cycling protection during reoxygenation conditions in the diaphragm. Copyright © 2015 the American Physiological Society.

Oxidant Mechanisms in Renal Injury and Disease

PubMed Central

Ratliff, Brian B.; Abdulmahdi, Wasan; Pawar, Rahul

2016-01-01

Abstract Significance: A common link between all forms of acute and chronic kidney injuries, regardless of species, is enhanced generation of reactive oxygen species (ROS) and reactive nitrogen species (RNS) during injury/disease progression. While low levels of ROS and RNS are required for prosurvival signaling, cell proliferation and growth, and vasoreactivity regulation, an imbalance of ROS and RNS generation and elimination leads to inflammation, cell death, tissue damage, and disease/injury progression. Recent Advances: Many aspects of renal oxidative stress still require investigation, including clarification of the mechanisms which prompt ROS/RNS generation and subsequent renal damage. However, we currently have a basic understanding of the major features of oxidative stress pathology and its link to kidney injury/disease, which this review summarizes. Critical Issues: The review summarizes the critical sources of oxidative stress in the kidney during injury/disease, including generation of ROS and RNS from mitochondria, NADPH oxidase, and inducible nitric oxide synthase. The review next summarizes the renal antioxidant systems that protect against oxidative stress, including superoxide dismutase and catalase, the glutathione and thioredoxin systems, and others. Next, we describe how oxidative stress affects kidney function and promotes damage in every nephron segment, including the renal vessels, glomeruli, and tubules. Future Directions: Despite the limited success associated with the application of antioxidants for treatment of kidney injury/disease thus far, preventing the generation and accumulation of ROS and RNS provides an ideal target for potential therapeutic treatments. The review discusses the shortcomings of antioxidant treatments previously used and the potential promise of new ones. Antioxid. Redox Signal. 25, 119–146. PMID:26906267

Substance P influenced gelatinolytic activity via reactive oxygen species in human pulp cells.

PubMed

Wang, F-M; Hu, T; Cheng, R; Tan, H; Zhou, X-D

2008-10-01

To investigate the effects of substance P (SP) on gelatinolytic activity of matrix metalloproteinases (MMPs) in human pulp cells. Human dental pulp cells were isolated and cultured. Subconfluent cells, between the third and sixth passages, were maintained under serum deprivation for 18 h followed by the treatment of varying doses of SP (1 pmol L(-1), 100 pmol L(-1), 10 nmol L(-1), 1 micromol L(-1) and 100 micromol L(-1)). Conditioned media were then subjected to gelatin zymography using 8% sodium dodecyl sulphate polyacrylamide gel electrophoresis minigels containing 1.5 g L(-1) gelatin. The effect of SP on intracellular reactive oxygen species (ROS) was also examined by confocal microscopy. ROS scavenger N-Acetyl-L-cysteine (NAC, 5 mmol L(-1)) was utilized to evaluate the roles of ROS pathway in mediating the impact of SP on cellular gelatinolytic activity. Data were analysed using analysis of variance with Bonferroni correction for multiple comparisons or an unpaired Student's t-test. Substance P, at levels above 1 micromol L(-1), remarkably enhanced MMP-2 activity reflected by the band migrating at 66 kDa (P < 0.05). A gelatinolytic band at approximately 44 kDa appeared to be intensified in a SP dose-dependent manner. In addition, it was demonstrated that SP could induce ROS production in pulp cells and ROS scavenger NAC was further found to significantly reduce MMP-2 activity (P < 0.05), as well as other bands of gelatinolytic proteinases. Substance P can influence gelatinolytic activity in human pulp cells via ROS pathway.

Din7 and Mhr1 expression levels regulate double-strand-break–induced replication and recombination of mtDNA at ori5 in yeast

PubMed Central

Ling, Feng; Hori, Akiko; Yoshitani, Ayako; Niu, Rong; Yoshida, Minoru; Shibata, Takehiko

2013-01-01

The Ntg1 and Mhr1 proteins initiate rolling-circle mitochondrial (mt) DNA replication to achieve homoplasmy, and they also induce homologous recombination to maintain mitochondrial genome integrity. Although replication and recombination profoundly influence mitochondrial inheritance, the regulatory mechanisms that determine the choice between these pathways remain unknown. In Saccharomyces cerevisiae, double-strand breaks (DSBs) introduced by Ntg1 at the mitochondrial replication origin ori5 induce homologous DNA pairing by Mhr1, and reactive oxygen species (ROS) enhance production of DSBs. Here, we show that a mitochondrial nuclease encoded by the nuclear gene DIN7 (DNA damage inducible gene) has 5′-exodeoxyribonuclease activity. Using a small ρ− mtDNA bearing ori5 (hypersuppressive; HS) as a model mtDNA, we revealed that DIN7 is required for ROS-enhanced mtDNA replication and recombination that are both induced at ori5. Din7 overproduction enhanced Mhr1-dependent mtDNA replication and increased the number of residual DSBs at ori5 in HS-ρ− cells and increased deletion mutagenesis at the ori5 region in ρ+ cells. However, simultaneous overproduction of Mhr1 suppressed all of these phenotypes and enhanced homologous recombination. Our results suggest that after homologous pairing, the relative activity levels of Din7 and Mhr1 modulate the preference for replication versus homologous recombination to repair DSBs at ori5. PMID:23598996

Effect of mitochondrial dysfunction and oxidative stress on endogenous levels of coenzyme Q(10) in human cells.

PubMed

Yen, Hsiu-Chuan; Chen, Feng-Yuan; Chen, Shih-Wei; Huang, Yu-Hsiang; Chen, Yun-Ru; Chen, Chih-Wei

2011-01-01

Little is known about the regulation of endogenous CoQ(10) levels in response to mitochondrial dysfunction or oxidative stress although exogenous CoQ(10) has been extensively used in humans. In this study, we first demonstrated that acute treatment of antimycin A, an inhibitor of mitochondrial complex III, and the absence of mitochondrial DNA suppressed CoQ(10) levels in human 143B cells. Because these two conditions also enhanced formation of reactive oxygen species (ROS), we further investigated whether oxidative stress or mitochondrial dysfunction primarily contributed to the decrease of CoQ(10) levels. Results showed that H(2)O(2) augmented CoQ(10) levels, but carbonyl cyanide-p-trifluoromethoxyphenylhydrazone (FCCP), a chemical uncoupler, decreased CoQ(10) levels in 143B cells. However, H(2)O(2) and FCCP both increased mRNA levels of multiple COQ genes for biosynthesis of CoQ(10) . Our findings suggest that ROS induced CoQ(10) biosynthesis, whereas mitochondrial energy deficiency caused secondary suppression of CoQ(10) levels possibly due to impaired import of COQ proteins into mitochondria. Copyright © 2011 Wiley Periodicals, Inc.

SMG-1 kinase attenuates mitochondrial ROS production but not cell respiration deficits during hyperoxia.

PubMed

Resseguie, Emily A; Brookes, Paul S; O'Reilly, Michael A

Supplemental oxygen (hyperoxia) used to treat individuals in respiratory distress causes cell injury by enhancing the production of toxic reactive oxygen species (ROS) and inhibiting mitochondrial respiration. The suppressor of morphogenesis of genitalia (SMG-1) kinase is activated during hyperoxia and promotes cell survival by phosphorylating the tumor suppressor p53 on serine 15. Here, we investigate whether SMG-1 and p53 blunt this vicious cycle of progressive ROS production and decline in mitochondrial respiration seen during hyperoxia. Human lung adenocarcinoma A549 and H1299 or colon carcinoma HCT116 cells were depleted of SMG-1, UPF-1, or p53 using RNA interference, and then exposed to room air (21% oxygen) or hyperoxia (95% oxygen). Immunoblotting was used to evaluate protein expression; a Seahorse Bioanalyzer was used to assess cellular respiration; and flow cytometry was used to evaluate fluorescence intensity of cells stained with mitochondrial or redox sensitive dyes. Hyperoxia increased mitochondrial and cytoplasmic ROS and suppressed mitochondrial respiration without changing mitochondrial mass or membrane potential. Depletion of SMG-1 or its cofactor, UPF1, significantly enhanced hyperoxia-induced mitochondrial but not cytosolic ROS abundance. They did not affect mitochondrial mass, membrane potential, or hyperoxia-induced deficits in mitochondrial respiration. Genetic depletion of p53 in A549 cells and ablation of the p53 gene in H1299 or HCT116 cells revealed that SMG-1 influences mitochondrial ROS through activation of p53. Our findings show that hyperoxia does not promote a vicious cycle of progressive mitochondrial ROS and dysfunction because SMG-1-p53 signaling attenuates production of mitochondrial ROS without preserving respiration. This suggests antioxidant therapies that blunt ROS production during hyperoxia may not suffice to restore cellular respiration.

Secretion pathway of liver IGF-1 via JAK2/STAT3 in chick embryo under the monochromatic light.

PubMed

Wang, Tuanjie; Dong, Yulan; Wang, Zixu; Cao, Jing; Chen, Yaoxing

2016-02-01

This study reveals mechanism of monochromatic light on the IGF-1 secretion of chick embryo liver. The chick embryos were incubated and exposed to continuous red, green, blue light or a dark environment. Compared to other light-treated groups, green light increased IGF-1 and melatonin concentrations both in plasma and liver, and Mel1a, Mel1b and Mel1c receptors expressions in liver but decreased p-JAK2, p-STAT3 and ROS in liver. IGF-1 had a positive correlation with melatonin, but a negative relevance with p-JAK2 and p-STAT3. In vitro, the IGF-1 level in the hepatocyte supernatant was enhanced by melatonin with lower p-JAK2/p-STAT3 and ROS levels, which was suppressed by Mel1c antagonist but not Mel1a/Mel1b or Mel1b antagonists. AG490 (JAK/STAT inhibitor) promoted role of melatonin-Mel1c modulated IGF-1 secretion. These results suggest the antioxidant effect of melatonin mediated the green light-enhanced IGF-1 secretion of chick embryo liver through Mel1c receptor to inhibit the JAK2/STAT3 pathway.

Overexpression of Soybean Isoflavone Reductase (GmIFR) Enhances Resistance to Phytophthora sojae in Soybean

PubMed Central

Cheng, Qun; Li, Ninghui; Dong, Lidong; Zhang, Dayong; Fan, Sujie; Jiang, Liangyu; Wang, Xin; Xu, Pengfei; Zhang, Shuzhen

2015-01-01

Isoflavone reductase (IFR) is an enzyme involved in the biosynthetic pathway of isoflavonoid phytoalexin in plants. IFRs are unique to the plant kingdom and are considered to have crucial roles in plant response to various biotic and abiotic environmental stresses. Here, we report the characterization of a novel member of the soybean isoflavone reductase gene family GmIFR. Overexpression of GmIFR transgenic soybean exhibited enhanced resistance to Phytophthora sojae. Following stress treatments, GmIFR was significantly induced by P. sojae, ethephon (ET), abscisic acid (placeCityABA), salicylic acid (SA). It is located in the cytoplasm when transiently expressed in soybean protoplasts. The daidzein levels reduced greatly for the seeds of transgenic plants, while the relative content of glyceollins in transgenic plants was significantly higher than that of non-transgenic plants. Furthermore, we found that the relative expression levels of reactive oxygen species (ROS) of transgenic soybean plants were significantly lower than those of non-transgenic plants after incubation with P. sojae, suggesting an important role of GmIFR might function as an antioxidant to reduce ROS in soybean. The enzyme activity assay suggested that GmIFR has isoflavone reductase activity. PMID:26635848

Overexpression of Soybean Isoflavone Reductase (GmIFR) Enhances Resistance to Phytophthora sojae in Soybean.

PubMed

Cheng, Qun; Li, Ninghui; Dong, Lidong; Zhang, Dayong; Fan, Sujie; Jiang, Liangyu; Wang, Xin; Xu, Pengfei; Zhang, Shuzhen

2015-01-01

Isoflavone reductase (IFR) is an enzyme involved in the biosynthetic pathway of isoflavonoid phytoalexin in plants. IFRs are unique to the plant kingdom and are considered to have crucial roles in plant response to various biotic and abiotic environmental stresses. Here, we report the characterization of a novel member of the soybean isoflavone reductase gene family GmIFR. Overexpression of GmIFR transgenic soybean exhibited enhanced resistance to Phytophthora sojae. Following stress treatments, GmIFR was significantly induced by P. sojae, ethephon (ET), abscisic acid (placeCityABA), salicylic acid (SA). It is located in the cytoplasm when transiently expressed in soybean protoplasts. The daidzein levels reduced greatly for the seeds of transgenic plants, while the relative content of glyceollins in transgenic plants was significantly higher than that of non-transgenic plants. Furthermore, we found that the relative expression levels of reactive oxygen species (ROS) of transgenic soybean plants were significantly lower than those of non-transgenic plants after incubation with P. sojae, suggesting an important role of GmIFR might function as an antioxidant to reduce ROS in soybean. The enzyme activity assay suggested that GmIFR has isoflavone reductase activity.

Reactive oxygen species' role in endothelial dysfunction by electron paramagnetic resonance

NASA Astrophysics Data System (ADS)

Wassall, Cynthia D.

The endothelium is a single layer of cells lining the arteries and is involved in many physiological reactions which are responsible for vascular tone. Free radicals are important participants in these chemical reactions in the endothelium. Here we quantify free radicals, ex vivo, in biological tissue with continuous wave electron paramagnetic resonance (EPR). In all of the experiments in this thesis, we use a novel EPR spin trapping technique that has been developed for tissue segments. EPR spin trapping is often considered the 'gold standard' in reactive oxygen species (ROS) detection because of its sensitivity and non-invasive nature. In all experiments, tissue was placed in physiological saline solution with 190-mM PBN (N-tert -butyl-α-phenylnitrone), 10% by volume dimethyl-sulphoxide (DMSO) for cryopreservation, and incubated in the dark for between 30 minutes up to 2 hours at 37°C while gently being stirred. Tissue and supernatant were then loaded into a syringe and frozen at -80°C until EPR analysis. In our experiments, the EPR spectra were normalized with respect to tissue volume. Conducting experiments at liquid nitrogen temperature leads to some experimental advantages. The freezing of the spin adducts renders them stable over a longer period, which allows ample time to analyze tissue samples for ROS. The dielectric constant of ice is greatly reduced over its liquid counterpart; this property of water enables larger sample volumes to be inserted into the EPR cavity without overloading it and leads to enhanced signal detection. Due to Maxwell-Boltzmann statistics, the population difference goes up as the temperature goes down, so this phenomenon enhances the signal intensity as well. With the 'gold standard' assertion in mind, we investigated whether slicing tissue to assay ROS that is commonly used in fluorescence experiments will show more free radical generation than tissue of a similar volume that remains unsliced. Sliced tissue exhibited a 76% increase in ROS generation; this implies that higher ROS concentrations in sliced tissue indicate extraneous ROS generation not associated with the ROS stimulus of interest. We also investigated the role of ROS in chronic flow overload (CFO). Elevation of shear stress that increases production of vascular ROS has not been well investigated. We hypothesize that CFO increases ROS production mediated in part by NADPH oxidase, which leads to endothelial dysfunction. ROS production increased threefold in response to CFO. The endothelium dependent vasorelaxation was compromised in the CFO group. Treatment with apocynin significantly reduced ROS production in the vessel wall, preserved endothelial function, and inhibited expressions of p22/p47phox and NOX2/NOX4. The present data implicate NADPH oxidase produced ROS and eNOS uncoupling in endothelial dysfunction at 1 wk of CFO. In further work, a swine right ventricular hypertrophy (RVH) model induced by pulmonary artery (PA) banding was used to study right coronary artery (RCA) endothelial function and ROS level. Endothelial function was compromised in RCA of RVH as attributed to insufficient endothelial nitric oxide synthase cofactor tetrahydrobiopterin. In conclusion, stretch due to outward remodeling of RCA during RVH (at constant wall shear stress), similar to vessel stretch in hypertension, appears to induce ROS elevation, endothelial dysfunction, and an increase in basal tone. Finally, although hypertension-induced vascular stiffness and dysfunction are well established in patients and animal models, we hypothesize that stretch or distension due to hypertension and outward expansion is the cause of endothelial dysfunction mediated by angiotensin II type 1 (AT1) receptor in coronary arteries. The expression and activation of AT1 receptor and the production of ROS were up regulated and endothelial function deteriorated in the RCA. The acute inhibition of AT1 receptor and NADPH oxidase partially restored the endothelial function. Stretch or distension activates the AT1 receptor which mediates ROS production; this collectively leads to endothelial dysfunction in coronary arteries.

Reactive Oxygen Species Function to Mediate the Fe Deficiency Response in an Fe-Efficient Apple Genotype: An Early Response Mechanism for Enhancing Reactive Oxygen Production

PubMed Central

Sun, Chaohua; Wu, Ting; Zhai, Longmei; Li, Duyue; Zhang, Xinzhong; Xu, Xuefeng; Ma, Huiqin; Wang, Yi; Han, Zhenhai

2016-01-01

Reactive oxygen species (ROS) are important signaling molecules in plants that contribute to stress acclimation. This study demonstrated that ROS play a critical role in Fe deficiency-induced signaling at an early stage in Malus xiaojinensis. Once ROS production has been initiated, prolonged Fe starvation leads to activation of ROS scavenging mechanisms. Further, we demonstrated that ROS scavengers are involved in maintaining the cellular redox homeostasis during prolonged Fe deficiency treatment. Taken together, our results describe a feedback repression loop for ROS to preserve redox homeostasis and maintain a continuous Fe deficiency response in the Fe-efficient woody plant M. xiaojinensis. More broadly, this study reveals a new mechanism in which ROS mediate both positive and negative regulation of plant responses to Fe deficiency stress. PMID:27899933

Ionized gas (plasma) delivery of reactive oxygen species (ROS) into artificial cells

NASA Astrophysics Data System (ADS)

Hong, Sung-Ha; Szili, Endre J.; Jenkins, A. Toby A.; Short, Robert D.

2014-09-01

This study was designed to enhance our understanding of how reactive oxygen species (ROS), generated ex situ by ionized gas (plasma), can affect the regulation of signalling processes within cells. A model system, comprising of a suspension of phospholipid vesicles (cell mimics) encapsulating a ROS reporter, was developed to study the plasma delivery of ROS into cells. For the first time it was shown that plasma unequivocally delivers ROS into cells over a sustained period and without compromising cell membrane integrity. An important consideration in cell and biological assays is the presence of serum, which significantly reduced the transfer efficiency of ROS into the vesicles. These results are key to understanding how plasma treatments can be tailored for specific medical or biotechnology applications. Further, the phospholipid vesicle ROS reporter system may find use in other studies involving the application of free radicals in biology and medicine.

OsACA6, a P-type IIB Ca²⁺ ATPase promotes salinity and drought stress tolerance in tobacco by ROS scavenging and enhancing the expression of stress-responsive genes.

PubMed

Huda, Kazi M K; Banu, M Sufara Akhter; Garg, Bharti; Tula, Suresh; Tuteja, Renu; Tuteja, Narendra

2013-12-01

Calcium (Ca²⁺) regulates several signalling pathways involved in growth, development and stress tolerance. Cellular Ca²⁺ homeostasis is achieved by the combined action of channels, pumps and antiporters, but direct evidence for a role of Ca²⁺ATPase pumps in stress tolerance is lacking. Here we report the characterization of a Ca²⁺ ATPase gene (OsACA6) from Oryza sativa, and elucidate its functions in stress tolerance. OsACA6 transcript levels are enhanced in response to salt, drought, abscisic acid and heat. In vivo localization identified plasma membranes as an integration site for the OsACA6-GFP fusion protein. Using transgenic tobacco lines, we demonstrate that over-expression of OsACA6 is triggered during salinity and drought stresses. The enhanced tolerance to these stresses was confirmed by changes in several physiological indices, including water loss rate, photosynthetic efficiency, cell membrane stability, germination, survival rate, malondialdehyde content, electrolyte leakage and increased proline accumulation. Furthermore, over-expressing lines also showed higher leaf chlorophyll and reduced accumulation of H₂O₂ and Na⁺ ions compared to the wild-type. Reduced accumulation of reactive oxygen species (ROS) was observed in transgenic lines. The increased proline accumulation and ROS scavenging enzyme activities in transgenic plants over-expressing OsACA6 efficiently modulate the ROS machinery and proline biosynthesis through an integrative mechanism. Transcriptional profiling of these plants revealed altered expression of genes encoding many transcription factors, stress- and disease-related proteins, as well as signalling components. These results suggest that Ca²⁺ ATPases have diverse roles as regulators of many stress signalling pathways, leading to plant growth, development and stress tolerance. © 2013 The Authors The Plant Journal © 2013 John Wiley & Sons Ltd.

Combined Effects of Rosuvastatin and Exercise on Gene Expression of Key Molecules Involved in Cholesterol Metabolism in Ovariectomized Rats

PubMed Central

Ngo Sock, Emilienne Tudor; Mayer, Gaétan; Lavoie, Jean-Marc

2016-01-01

The purpose of this study was to investigate the effects of three weeks of rosuvastatin (Ros) treatment alone and in combination with voluntary training (Tr) on expression of genes involved in cholesterol metabolism (LDLR, PCSK9, LRP-1, SREBP-2, IDOL, ACAT-2 and HMGCR) in the liver of eight week-old ovariectomized (Ovx) rats. Sprague Dawley rats were Ovx or sham-operated (Sham) and kept sedentary for 8 weeks under a standard diet. Thereafter, rats were transferred for three weeks in running wheel cages for Tr or kept sedentary (Sed) with or without Ros treatment (5mg/kg/day). Six groups were formed: Sham-Sed treated with saline (Sal) or Ros (Sham-Sed-Sal; Sham-Sed-Ros), Ovx-Sed treated with Sal or Ros (Ovx-Sed-Sal; Ovx-Sed-Ros), Ovx trained treated with Sal or Ros (Ovx-Tr-Sal; Ovx-Tr-Ros). Ovx-Sed-Sal rats depicted higher (P < 0.05) body weight, plasma total cholesterol (TC) and LDL-C, and liver TC content compared to Sham-Sed-Sal rats. In contrast, mRNA levels of liver PCSK9, LDLR, LRP-1 as well as plasma PCSK9 concentrations and protein levels of LRP-1 were reduced (P < 0.01) in Ovx-Sed-Sal compared to Sham-Sed-Sal rats. However, protein levels of LDLR increased (P < 0.05) in Ovx-Sed-Sal compared to Sham-Sed-Sal rats. Treatment of Ovx rats with Ros increased (P < 0.05) mRNA and protein levels of LRP-1 and PCSK9 but not mRNA levels of LDLR, while its protein abundance was reduced at the level of Sham rats. As a result, plasma LDL-C was not reduced. Exercise alone did not affect the expression of any of these markers in Ovx rats. Overall, Ros treatment corrected Ovx-induced decrease in gene expression of markers of cholesterol metabolism in liver of Ovx rats, but without reducing plasma LDL-C concentrations. Increased plasma PCSK9 levels could be responsible for the reduction of liver LDLR protein abundance and the absence of reduction of plasma LDL-C after Ros treatment. PMID:27442011

Fast, transient and specific intracellular ROS changes in living root hair cells responding to Nod factors (NFs).

PubMed

Cárdenas, Luis; Martínez, Adán; Sánchez, Federico; Quinto, Carmen

2008-12-01

The role of reactive oxygen species (ROS) in root-nodule development and metabolism has been extensively studied. However, there is limited evidence showing ROS changes during the earliest stages of the interaction between legumes and rhizobia. Herein, using ratio-imaging analysis, increasing and transient ROS levels were detected at the tips of actively growing root hair cells within seconds after addition of Nod factors (NFs). This transient response (which lasted up to 3 min) was Nod-factor-specific, as chitin oligomers (pentamers) failed to induce a similar response. When chitosan, a fungal elicitor, or ATP was used instead, a sustained increasing signal was observed. As ROS levels are transiently elevated after the perception of NFs, we propose that this ROS response is characteristic of the symbiotic interaction. Furthermore, we discuss the remarkable spatial and temporal coincidences between ROS and transiently increased calcium levels observed in root hair cells immediately after the detection of NFs.

The role of reactive oxygen species in methamphetamine self-administration and dopamine release in the nucleus accumbens.

PubMed

Jang, Eun Young; Yang, Chae Ha; Hedges, David M; Kim, Soo Phil; Lee, Jun Yeon; Ekins, Tyler G; Garcia, Brandon T; Kim, Hee Young; Nelson, Ashley C; Kim, Nam Jun; Steffensen, Scott C

2017-09-01

Methamphetamine (METH) markedly increases dopamine (DA) release in the mesolimbic DA system, which plays an important role in mediating the reinforcing effects of METH. METH-induced DA release results in the formation of reactive oxygen species (ROS), leading to oxidative damage. We have recently reported that ROS are implicated in behavior changes and DA release in the nucleus accumbens (NAc) following cocaine administration. The aim of this study was to evaluate the involvement of ROS in METH-induced locomotor activity, self-administration and enhancement of DA release in the NAc. Systemic administration of a non-specific ROS scavenger, N-tert-butyl-α-phenylnitrone (PBN; 0, 50 and 75 mg/kg, IP) or a superoxide-selective scavenger, 4-hydroxy-2,2,6,6-tetramethylpiperidine-1-oxyl (TEMPOL; 0, 50 and 100 mg/kg, IP), attenuated METH-induced locomotor activity without affecting generalized behavior in METH-naïve rats. PBN and TEMPOL significantly attenuated METH self-administration without affecting food intake. Increased oxidative stress was found in neurons, but not astrocytes, microglia or oligodendrocytes, in the NAc of METH self-administering rats. In addition, TEMPOL significantly decreased METH enhancement of DA release in the NAc. Taken together, these results suggest that enhancement of ROS in the NAc contributes to the reinforcing effect of METH. © 2016 Society for the Study of Addiction.

ROS-induced toxicity: exposure of 3T3, RAW264.7, and MCF7 cells to superparamagnetic iron oxide nanoparticles results in cell death by mitochondria-dependent apoptosis

NASA Astrophysics Data System (ADS)

Hsieh, Hui-Chen; Chen, Chung-Ming; Hsieh, Wen-Yuan; Chen, Ching-Yun; Liu, Chia-Ching; Lin, Feng-Huei

2015-02-01

Superparamagnetic nanoparticles (Fe3O4, SPIO) have been used as magnetic resonance imaging enhancers for years. However, bio-safety issues concerning nanoparticles remain largely unexplored. Of particular concern is the possible cellular impact of nanoparticles during SPIO uptake and subsequent oxidative stress. SPIO causes cell death by apoptosis via a little understood mitochondrial pathway. To more closely examine this process, three kinds of cells—3T3, RAW264.7, and MCF7—were treated with SPIO coated with polyethylene glycol (SPIO-PEG) and monitored by transmission electron microscopy (TEM), using cytotoxicity evaluation, mitochondrial activity, reactive oxygen species (ROS) generation, and Annexin V assay. TEM revealed that SPIO-PEG nanoparticles surrounded the cellular endosome membrane, creating a bulge in the endosome. Compared to 3T3 cells, greater numbers of SPIO-PEG nanoparticles infiltrated the mitochondria of RAW264.7 and MCF7 cells. SPIO-PEG residency is associated with boosted ROS, with elevated levels of mitochondrial activity, and advancement of cell apoptosis. Furthermore, correlation analysis showed that a polynomial model demonstrates a better fit than a linear model in MCF7, implying that cytotoxicity may have alternative impacts on cell death at different concentrations. Thus, we believe that MCF7 cell death results from the apoptosis pathway triggered by mitochondria, and we find lower cytotoxicity in 3T3. We propose that optimal levels of SPIO-PEG nanoparticles lead to increased levels of ROS and a resulting oxidative stress environment which will kill only cancer cells while sparing normal cells. This finding has great potential for use in cancer therapies in the future.

From Endoplasmic Reticulum to Mitochondria: Absence of the Arabidopsis ATP Antiporter Endoplasmic Reticulum Adenylate Transporter1 Perturbs Photorespiration[W

PubMed Central

Hoffmann, Christiane; Plocharski, Bartolome; Haferkamp, Ilka; Leroch, Michaela; Ewald, Ralph; Bauwe, Hermann; Riemer, Jan; Herrmann, Johannes M.; Neuhaus, H. Ekkehard

2013-01-01

The carrier Endoplasmic Reticulum Adenylate Transporter1 (ER-ANT1) resides in the endoplasmic reticulum (ER) membrane and acts as an ATP/ADP antiporter. Mutant plants lacking ER-ANT1 exhibit a dwarf phenotype and their seeds contain reduced protein and lipid contents. In this study, we describe a further surprising metabolic peculiarity of the er-ant1 mutants. Interestingly, Gly levels in leaves are immensely enhanced (26×) when compared with that of wild-type plants. Gly accumulation is caused by significantly decreased mitochondrial glycine decarboxylase (GDC) activity. Reduced GDC activity in mutant plants was attributed to oxidative posttranslational protein modification induced by elevated levels of reactive oxygen species (ROS). GDC activity is crucial for photorespiration; accordingly, morphological and physiological defects in er-ant1 plants were nearly completely abolished by application of high environmental CO2 concentrations. The latter observation demonstrates that the absence of ER-ANT1 activity mainly affects photorespiration (maybe solely GDC), whereas basic cellular metabolism remains largely unchanged. Since ER-ANT1 homologs are restricted to higher plants, it is tempting to speculate that this carrier fulfils a plant-specific function directly or indirectly controlling cellular ROS production. The observation that ER-ANT1 activity is associated with cellular ROS levels reveals an unexpected and critical physiological connection between the ER and other organelles in plants. PMID:23860249

The role of Hibiscus sabdariffa L. (Roselle) in maintenance of ex vivo murine bone marrow-derived hematopoietic stem cells.

PubMed

Abdul Hamid, Zariyantey; Lin Lin, Winnie Hii; Abdalla, Basma Jibril; Bee Yuen, Ong; Latif, Elda Surhaida; Mohamed, Jamaludin; Rajab, Nor Fadilah; Paik Wah, Chow; Wak Harto, Muhd Khairul Akmal; Budin, Siti Balkis

2014-01-01

Hematopoietic stem cells- (HSCs-) based therapy requires ex vivo expansion of HSCs prior to therapeutic use. However, ex vivo culture was reported to promote excessive production of reactive oxygen species (ROS), exposing HSCs to oxidative damage. Efforts to overcome this limitation include the use of antioxidants. In this study, the role of Hibiscus sabdariffa L. (Roselle) in maintenance of cultured murine bone marrow-derived HSCs was investigated. Aqueous extract of Roselle was added at varying concentrations (0-1000 ng/mL) for 24 hours to the freshly isolated murine bone marrow cells (BMCs) cultures. Effects of Roselle on cell viability, reactive oxygen species (ROS) production, glutathione (GSH) level, superoxide dismutase (SOD) activity, and DNA damage were investigated. Roselle enhanced the survival (P < 0.05) of BMCs at 500 and 1000 ng/mL, increased survival of Sca-1(+) cells (HSCs) at 500 ng/mL, and maintained HSCs phenotype as shown from nonremarkable changes of surface marker antigen (Sca-1) expression in all experimental groups. Roselle increased (P < 0.05) the GSH level and SOD activity but the level of reactive oxygen species (ROS) was unaffected. Moreover, Roselle showed significant cellular genoprotective potency against H2O2-induced DNA damage. Conclusively, Roselle shows novel property as potential supplement and genoprotectant against oxidative damage to cultured HSCs.

Folic acid protects against arsenic-mediated embryo toxicity by up-regulating the expression of Dvr1

PubMed Central

Ma, Yan; Zhang, Chen; Gao, Xiao-Bo; Luo, Hai-Yan; Chen, Yang; Li, Hui-hua; Ma, Xu; Lu, Cai-Ling

2015-01-01

As a nutritional factor, folic acid can prevent cardiac and neural defects during embryo development. Our previous study showed that arsenic impairs embryo development by down-regulating Dvr1/GDF1 expression in zebrafish. Here, we investigated whether folic acid could protect against arsenic-mediated embryo toxicity. We found that folic acid supplementation increases hatching and survival rates, decreases malformation rate and ameliorates abnormal cardiac and neural development of zebrafish embryos exposed to arsenite. Both real-time PCR analysis and whole in-mount hybridization showed that folic acid significantly rescued the decrease in Dvr1 expression caused by arsenite. Subsequently, our data demonstrated that arsenite significantly decreased cell viability and GDF1 mRNA and protein levels in HEK293ET cells, while folic acid reversed these effects. Folic acid attenuated the increase in subcellular reactive oxygen species (ROS) levels and oxidative adaptor p66Shc protein expression in parallel with the changes in GDF1 expression and cell viability. P66Shc knockdown significantly inhibited the production of ROS and the down-regulation of GDF1 induced by arsenite. Our data demonstrated that folic acid supplementation protected against arsenic-mediated embryo toxicity by up-regulating the expression of Dvr1/GDF1, and folic acid enhanced the expression of GDF1 by decreasing p66Shc expression and subcellular ROS levels. PMID:26537450

Oxidative stress response in SH-SY5Y cells exposed to short-term 1800 MHz radiofrequency radiation.

PubMed

Marjanovic Cermak, Ana Marija; Pavicic, Ivan; Trosic, Ivancica

2018-01-28

The exact mechanism that could explain the effects of radiofrequency (RF) radiation exposure at non-thermal level is still unknown. Increasing evidence suggests a possible involvement of reactive oxygen species (ROS) and development of oxidative stress. To test the proposed hypothesis, human neuroblastoma cells (SH-SY5Y) were exposed to 1800 MHz short-term RF exposure for 10, 30 and 60 minutes. Electric field strength within Gigahertz Transverse Electromagnetic cell (GTEM) was 30 V m -1 and specific absorption rate (SAR) was calculated to be 1.6 W kg -1 . Cellular viability was measured by MTT assay and level of ROS was determined by fluorescent probe 2',7'-dichlorofluorescin diacetate. Concentrations of malondialdehyde and protein carbonyls were used to assess lipid and protein oxidative damage and antioxidant activity was evaluated by measuring concentrations of total glutathione (GSH). After radiation exposure, viability of irradiated cells remained within normal physiological values. Significantly higher ROS level was observed for every radiation exposure time. After 60 min of exposure, the applied radiation caused significant lipid and protein damage. The highest GSH concentration was detected after 10 minute-exposure. The results of our study showed enhanced susceptibility of SH-SY5Y cells for development of oxidative stress even after short-term RF exposure.

The Role of Hibiscus sabdariffa L. (Roselle) in Maintenance of Ex Vivo Murine Bone Marrow-Derived Hematopoietic Stem Cells

PubMed Central

Abdul Hamid, Zariyantey; Lin Lin, Winnie Hii; Abdalla, Basma Jibril; Bee Yuen, Ong; Latif, Elda Surhaida; Mohamed, Jamaludin; Rajab, Nor Fadilah; Paik Wah, Chow; Budin, Siti Balkis

2014-01-01

Hematopoietic stem cells- (HSCs-) based therapy requires ex vivo expansion of HSCs prior to therapeutic use. However, ex vivo culture was reported to promote excessive production of reactive oxygen species (ROS), exposing HSCs to oxidative damage. Efforts to overcome this limitation include the use of antioxidants. In this study, the role of Hibiscus sabdariffa L. (Roselle) in maintenance of cultured murine bone marrow-derived HSCs was investigated. Aqueous extract of Roselle was added at varying concentrations (0–1000 ng/mL) for 24 hours to the freshly isolated murine bone marrow cells (BMCs) cultures. Effects of Roselle on cell viability, reactive oxygen species (ROS) production, glutathione (GSH) level, superoxide dismutase (SOD) activity, and DNA damage were investigated. Roselle enhanced the survival (P < 0.05) of BMCs at 500 and 1000 ng/mL, increased survival of Sca-1+ cells (HSCs) at 500 ng/mL, and maintained HSCs phenotype as shown from nonremarkable changes of surface marker antigen (Sca-1) expression in all experimental groups. Roselle increased (P < 0.05) the GSH level and SOD activity but the level of reactive oxygen species (ROS) was unaffected. Moreover, Roselle showed significant cellular genoprotective potency against H2O2-induced DNA damage. Conclusively, Roselle shows novel property as potential supplement and genoprotectant against oxidative damage to cultured HSCs. PMID:25405216

Inhibition of mTOR Prevents ROS Production Initiated by Ethidium Bromide-Induced Mitochondrial DNA Depletion

PubMed Central

Nacarelli, Timothy; Azar, Ashley; Sell, Christian

2014-01-01

The regulation of mitochondrial mass and DNA content involves a complex interaction between mitochondrial DNA replication machinery, functional components of the electron transport chain, selective clearance of mitochondria, and nuclear gene expression. In order to gain insight into cellular responses to mitochondrial stress, we treated human diploid fibroblasts with ethidium bromide at concentrations that induced loss of mitochondrial DNA over a period of 7 days. The decrease in mitochondrial DNA was accompanied by a reduction in steady state levels of the mitochondrial DNA binding protein, TFAM, a reduction in several electron transport chain protein levels, increased mitochondrial and total cellular ROS, and activation of p38 MAPK. However, there was an increase in mitochondrial mass and voltage dependent anion channel levels. In addition, mechanistic target of rapamycin (mTOR) activity, as judged by p70S6K targets, was decreased while steady state levels of p62/SQSTM1 and Parkin were increased. Treatment of cells with rapamycin created a situation in which cells were better able to adapt to the mitochondrial dysfunction, resulting in decreased ROS and increased cell viability but did not prevent the reduction in mitochondrial DNA. These effects may be due to a more efficient flux through the electron transport chain, increased autophagy, or enhanced AKT signaling, coupled with a reduced growth rate. Together, the results suggest that mTOR activity is affected by mitochondrial stress, which may be part of the retrograde signal system required for normal mitochondrial homeostasis. PMID:25104948

Production of reactive oxygen species in brain mitochondria: contribution by electron transport chain and non-electron transport chain sources.

PubMed

Adam-Vizi, Vera

2005-01-01

Overwhelming evidence has accumulated indicating that oxidative stress is a crucial factor in the pathogenesis of neurodegenerative diseases. The major site of production of superoxide, the primary reactive oxygen species (ROS), is considered to be the respiratory chain in the mitochondria, but the exact mechanism and the precise location of the physiologically relevant ROS generation within the respiratory chain have not been disclosed as yet. Studies performed with isolated mitochondria have located ROS generation on complex I and complex III, respectively, depending on the substrates or inhibitors used to fuel or inhibit respiration. A more "physiological" approach is to address ROS generation of in situ mitochondria, which are present in their normal cytosolic environment. Hydrogen peroxide formation in mitochondria in situ in isolated nerve terminals is enhanced when complex I, complex III, or complex IV is inhibited. However, to induce a significant increase in ROS production, complex III and complex IV have to be inhibited by >70%, which raises doubts as to the physiological importance of ROS generation by these complexes. In contrast, complex I inhibition to a small degree is sufficient to enhance ROS generation, indicating that inhibition of complex I by approximately 25-30% observed in postmortem samples of substantia nigra from patients suffering from Parkinson's disease could be important in inducing oxidative stress. Recently, it has been described that a key Krebs cycle enzyme, alpha-ketoglutarate dehydrogenase (alpha-KGDH), is also able to produce ROS. ROS formation by alpha-KGDH is regulated by the NADH/NAD+ ratio, suggesting that this enzyme could substantially contribute to generation of oxidative stress due to inhibition of complex I. As alpha-KGDH is not only a generator but also a target of ROS, it is proposed that alpha-KGDH is a key factor in a vicious cycle by which oxidative stress is induced and promoted in nerve terminals.

Application of glycerol as a foliar spray activates the defence response and enhances disease resistance of Theobroma cacao.

PubMed

Zhang, Yufan; Smith, Philip; Maximova, Siela N; Guiltinan, Mark J

2015-01-01

Previous work has implicated glycerol-3-phosphate (G3P) as a mobile inducer of systemic immunity in plants. We tested the hypothesis that the exogenous application of glycerol as a foliar spray might enhance the disease resistance of Theobroma cacao through the modulation of endogenous G3P levels. We found that exogenous application of glycerol to cacao leaves over a period of 4 days increased the endogenous level of G3P and decreased the level of oleic acid (18:1). Reactive oxygen species (ROS) were produced (a marker of defence activation) and the expression of many pathogenesis-related genes was induced. Notably, the effects of glycerol application on G3P and 18:1 fatty acid content, and gene expression levels, in cacao leaves were dosage dependent. A 100 mm glycerol spray application was sufficient to stimulate the defence response without causing any observable damage, and resulted in a significantly decreased lesion formation by the cacao pathogen Phytophthora capsici; however, a 500 mm glycerol treatment led to chlorosis and cell death. The effects of glycerol treatment on the level of 18:1 and ROS were constrained to the locally treated leaves without affecting distal tissues. The mechanism of the glycerol-mediated defence response in cacao and its potential use as part of a sustainable farming system are discussed. © 2014 BSPP AND JOHN WILEY & SONS LTD.

Triclosan activates aryl hydrocarbon receptor (AhR)-dependent apoptosis and affects Cyp1a1 and Cyp1b1 expression in mouse neocortical neurons.

PubMed

Szychowski, Konrad A; Wnuk, Agnieszka; Kajta, Małgorzata; Wójtowicz, Anna K

2016-11-01

Triclosan (TCS) is an antimicrobial agent that is used extensively in personal care and in sanitizing products, such as soaps, toothpastes, and hair products. A number of studies have revealed the presence of TCS in human tissues, such as fat, liver and brain, in addition to blood and breast milk. The aim of the present study was to investigate the impact of TCS on AhR and Cyp1a1/Cyp1b1 signaling in mouse neocortical neurons in primary cultures. In addition to the use of selective ligands and siRNAs, expression levels of mRNA and proteins as well as caspase-3 activity, reactive oxygen species (ROS) formation, and lactate dehydrogenase (LDH) release have been measured. We also studied the involvement of the AhR in TCS-induced LDH release and caspase-3 activation as well as the effect of TCS on ROS generation. Cultures of neocortical neurons were prepared from Swiss mouse embryos on day 15/16 of gestation. The cells were cultured in phenol red-free Neurobasal medium with B27 and glutamine, and the neurons were exposed to 1 and 10µM TCS. Our experiments showed that the expression of AhR and Cyp1a1 mRNA decreased in cells exposed to 10µM TCS for 3 or 6h. In the case of Cyp1b1, mRNA expression remained unchanged compared with the control group following 3h of exposure to TCS, but after 6h, the mRNA expression of Cyp1b1 was decreased. Our results confirmed that the AhR is involved in the TCS mechanism of action, and our data demonstrated that after the cells were transfected with AhR siRNA, the cytotoxic and pro-apoptotic properties of TCS were decreased. The decrease in Cyp1a1 mRNA and protein expression levels accompanied by a decrease in its activity. The stimulation of Cyp1a1 activity produced by the application of an AhR agonist (βNF) was attenuated by TCS, whereas the addition of AhR antagonist (αNF) reversed the inhibitory effects of TCS. In our experiments, TCS diminished Cyp1b1 mRNA and enhanced its protein expression. In case of Cyp1a1 we observed paradoxical effect of TCS action, which caused the decrease in activity and protein expression of Cyp1a1 and the increase in protein level of AhR. Therefore, we determined the effects of TCS on the production of ROS. Our results revealed that TCS increased the production of ROS and that this effect of TCS was reversed by 10µM N-acetyl-L-cysteine (NAC), the ROS scavenger. To confirm an involvement of ROS in TCS-induced neurotoxicity we measured AhR, Cyp1a1, and Cyp1b1 mRNA expression levels in cells co-treated with TCS and NAC. In the presence of NAC, TCS enhanced mRNA expression of the cytochromes and AhR at 3 and 6h, respectively. We postulate that TCS exhibits primary and secondary effects. The primary effects such as impairment of Cyp1a1 signaling are mediated by TCS-induced ROS production, whereas secondary effects of TCS are due to transcriptional activity of AhR and estrogenic properties of TCS. Copyright © 2016 Elsevier Inc. All rights reserved.

Antioxidant potential of CORM-A1 and resveratrol during TNF-α/cycloheximide-induced oxidative stress and apoptosis in murine intestinal epithelial MODE-K cells

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

Babu, Dinesh, E-mail: dinesh.babu@ugent.be; Leclercq, Georges; Goossens, Vera

2015-10-15

Targeting excessive production of reactive oxygen species (ROS) could be an effective therapeutic strategy to prevent oxidative stress-associated gastrointestinal inflammation. NADPH oxidase (NOX) and mitochondrial complexes (I and II) are the major sources of ROS production contributing to TNF-α/cycloheximide (CHX)-induced apoptosis in the mouse intestinal epithelial cell line, MODE-K. In the current study, the influence of a polyphenolic compound (resveratrol) and a water-soluble carbon monoxide (CO)-releasing molecule (CORM-A1) on the different sources of TNF-α/CHX-induced ROS production in MODE-K cells was assessed. This was compared with H{sub 2}O{sub 2}-, rotenone- or antimycin-A-induced ROS-generating systems. Intracellular total ROS, mitochondrial-derived ROS and mitochondrialmore » superoxide anion (O{sub 2}·{sup −}) production levels were assessed. Additionally, the influence on TNF-α/CHX-induced changes in mitochondrial membrane potential (Ψ{sub m}) and mitochondrial function was studied. In basal conditions, CORM-A1 did not affect intracellular total or mitochondrial ROS levels, while resveratrol increased intracellular total ROS but reduced mitochondrial ROS production. TNF-α/CHX- and H{sub 2}O{sub 2}-mediated increase in intracellular total ROS production was reduced by both resveratrol and CORM-A1, whereas only resveratrol attenuated the increase in mitochondrial ROS triggered by TNF-α/CHX. CORM-A1 decreased antimycin-A-induced mitochondrial O{sub 2}·{sup −} production without any influence on TNF-α/CHX- and rotenone-induced mitochondrial O{sub 2}·{sup −} levels, while resveratrol abolished all three effects. Finally, resveratrol greatly reduced and abolished TNF-α/CHX-induced mitochondrial depolarization and mitochondrial dysfunction, while CORM-A1 only mildly affected these parameters. These data indicate that the cytoprotective effect of resveratrol is predominantly due to mitigation of mitochondrial ROS, while CORM-A1 acts solely on NOX-derived ROS to protect MODE-K cells from TNF-α/CHX-induced cell death. This might explain the more pronounced cytoprotective effect of resveratrol. - Highlights: • In MODE-K IECs, TNF-α/CHX induces correlating ROS, mitochondrial O{sub 2}·{sup −} and cell death. • CORM-A1 does not influence basal intracellular ROS and mitochondrial O{sub 2}·{sup −} levels. • Resveratrol increases basal intracellular ROS but decreases mitochondrial O{sub 2}·{sup −} levels. • CORM-A1 acts solely on NOX-derived ROS to protect from cell death by TNF-α/CHX. • Cytoprotection by resveratrol is predominantly due to reduction of mitochondrial O{sub 2}·{sup −}.« less

Oxidative Stress, Bone Marrow Failure, and Genome Instability in Hematopoietic Stem Cells

PubMed Central

Richardson, Christine; Yan, Shan; Vestal, C. Greer

2015-01-01

Reactive oxygen species (ROS) can be generated by defective endogenous reduction of oxygen by cellular enzymes or in the mitochondrial respiratory pathway, as well as by exogenous exposure to UV or environmental damaging agents. Regulation of intracellular ROS levels is critical since increases above normal concentrations lead to oxidative stress and DNA damage. A growing body of evidence indicates that the inability to regulate high levels of ROS leading to alteration of cellular homeostasis or defective repair of ROS-induced damage lies at the root of diseases characterized by both neurodegeneration and bone marrow failure as well as cancer. That these diseases may be reflective of the dynamic ability of cells to respond to ROS through developmental stages and aging lies in the similarities between phenotypes at the cellular level. This review summarizes work linking the ability to regulate intracellular ROS to the hematopoietic stem cell phenotype, aging, and disease. PMID:25622253

Recent advances in intracellular and in vivo ROS sensing: focus on nanoparticle and nanotube applications.

PubMed

Uusitalo, Larissa M; Hempel, Nadine

2012-01-01

Reactive oxygen species (ROS) are increasingly being implicated in the regulation of cellular signaling cascades. Intracellular ROS fluxes are associated with cellular function ranging from proliferation to cell death. Moreover, the importance of subtle, spatio-temporal shifts in ROS during localized cellular signaling events is being realized. Understanding the biochemical nature of the ROS involved will enhance our knowledge of redox-signaling. An ideal intracellular sensor should therefore resolve real-time, localized ROS changes, be highly sensitive to physiologically relevant shifts in ROS and provide specificity towards a particular molecule. For in vivo applications issues such as bioavailability of the probe, tissue penetrance of the signal and signal-to-noise ratio also need to be considered. In the past researchers have heavily relied on the use of ROS-sensitive fluorescent probes and, more recently, genetically engineered ROS sensors. However, there is a great need to improve on current methods to address the above issues. Recently, the field of molecular sensing and imaging has begun to take advantage of the unique physico-chemical properties of nanoparticles and nanotubes. Here we discuss the recent advances in the use of these nanostructures as alternative platforms for ROS sensing, with particular emphasis on intracellular and in vivo ROS detection and quantification.

A crucial role for thiol antioxidants in estrogen-deficiency bone loss

PubMed Central

Lean, Jenny M.; Davies, Julie T.; Fuller, Karen; Jagger, Christopher J.; Kirstein, Barrie; Partington, Geoffrey A.; Urry, Zoë L.; Chambers, Timothy J.

2003-01-01

The mechanisms through which estrogen prevents bone loss are uncertain. Elsewhere, estrogen exerts beneficial actions by suppression of reactive oxygen species (ROS). ROS stimulate osteoclasts, the cells that resorb bone. Thus, estrogen might prevent bone loss by enhancing oxidant defenses in bone. We found that glutathione and thioredoxin, the major thiol antioxidants, and glutathione and thioredoxin reductases, the enzymes responsible for maintaining them in a reduced state, fell substantially in rodent bone marrow after ovariectomy and were rapidly normalized by exogenous 17-β estradiol. Moreover, administration of N-acetyl cysteine (NAC) or ascorbate, antioxidants that increase tissue glutathione levels, abolished ovariectomy-induced bone loss, while L-buthionine-(S,R)-sulphoximine (BSO), a specific inhibitor of glutathione synthesis, caused substantial bone loss. The 17-β estradiol increased glutathione and glutathione and thioredoxin reductases in osteoclast-like cells in vitro. Furthermore, in vitro NAC prevented osteoclast formation and NF-κB activation. BSO and hydrogen peroxide did the opposite. Expression of TNF-α, a target for NF-κB and a cytokine strongly implicated in estrogen-deficiency bone loss, was suppressed in osteoclasts by 17-β estradiol and NAC. These observations strongly suggest that estrogen deficiency causes bone loss by lowering thiol antioxidants in osteoclasts. This directly sensitizes osteoclasts to osteoclastogenic signals and entrains ROS-enhanced expression of cytokines that promote osteoclastic bone resorption. PMID:12975476

In vitro additive antitumor effects of dimethoxycurcumin and 5-fluorouracil in colon cancer cells.

PubMed

Zhao, Huiying; Liu, Qingchun; Wang, Saisai; Dai, Fang; Cheng, Xiaofei; Cheng, Xiaobin; Chen, Wenbin; Zhang, Min; Chen, Dong

2017-07-01

Dimethoxycurcumin (DMC) is a lipophilic analog of curcumin, an effective treatment for colon cancer, which has greater chemical and metabolic stability. Chemotherapy treatments, such as 5-fluorouracil (5-Fu), play a key role in the current management of colon cancer. In this study, we investigated the antitumor efficacy of DMC in combination with 5-Fu in SW480 and SW620 colon cancer cells. CCK-8 assay was used to evaluate the inhibitory effect of DMC and 5-Fu on cancer cells proliferation, and the combination index was calculated. The influence of DMC and 5-Fu on cell cycle, apoptosis, reactive oxygen species (ROS) production, and mitochondrial membrane potential in SW480 and SW620 cells was determined using flow cytometry, and the related signaling pathways were detected by western blot. Transmission electron microscopy was used to observe endoplasmic reticulum expansion. DMC- and/or 5-Fu-induced apoptosis, stimulated G0/G1 phase arrest, increased ROS levels, decreased mitochondrial membrane potential, and enhanced endoplasmic reticulum expansion. The induction of apoptosis is involved in the increasing of Bax and cytochrome c and decreasing of Bcl2 expressions. Increased production of ROS was accompanied by upregulation of CHOP and Noxa. Combination therapy of DMC and 5-Fu had increased efficacy on the above pathways compared with either drug alone. Based on the calculated IC 50 , combination treatment with DMC and 5-Fu had an additive antitumor effect in both cell lines. Combined treatment with DMC and 5-Fu led to an additive antitumor effect in colon cancer cells that was related to apoptosis induction, G0/G1 phase arrest, increased ROS production, decreased mitochondrial membrane potential, and enhanced endoplasmic reticulum expansion. © 2017 The Authors. Cancer Medicine published by John Wiley & Sons Ltd.

Hydrogen peroxide priming modulates abiotic oxidative stress tolerance: insights from ROS detoxification and scavenging

PubMed Central

Hossain, Mohammad A.; Bhattacharjee, Soumen; Armin, Saed-Moucheshi; Qian, Pingping; Xin, Wang; Li, Hong-Yu; Burritt, David J.; Fujita, Masayuki; Tran, Lam-Son P.

2015-01-01

Plants are constantly challenged by various abiotic stresses that negatively affect growth and productivity worldwide. During the course of their evolution, plants have developed sophisticated mechanisms to recognize external signals allowing them to respond appropriately to environmental conditions, although the degree of adjustability or tolerance to specific stresses differs from species to species. Overproduction of reactive oxygen species (ROS; hydrogen peroxide, H2O2; superoxide, O2⋅-; hydroxyl radical, OH⋅ and singlet oxygen, 1O2) is enhanced under abiotic and/or biotic stresses, which can cause oxidative damage to plant macromolecules and cell structures, leading to inhibition of plant growth and development, or to death. Among the various ROS, freely diffusible and relatively long-lived H2O2 acts as a central player in stress signal transduction pathways. These pathways can then activate multiple acclamatory responses that reinforce resistance to various abiotic and biotic stressors. To utilize H2O2 as a signaling molecule, non-toxic levels must be maintained in a delicate balancing act between H2O2 production and scavenging. Several recent studies have demonstrated that the H2O2-priming can enhance abiotic stress tolerance by modulating ROS detoxification and by regulating multiple stress-responsive pathways and gene expression. Despite the importance of the H2O2-priming, little is known about how this process improves the tolerance of plants to stress. Understanding the mechanisms of H2O2-priming-induced abiotic stress tolerance will be valuable for identifying biotechnological strategies to improve abiotic stress tolerance in crop plants. This review is an overview of our current knowledge of the possible mechanisms associated with H2O2-induced abiotic oxidative stress tolerance in plants, with special reference to antioxidant metabolism. PMID:26136756

Agmatine Reduces Lipopolysaccharide-Mediated Oxidant Response via Activating PI3K/Akt Pathway and Up-Regulating Nrf2 and HO-1 Expression in Macrophages

PubMed Central

Chai, Jianshen; Luo, Li; Hou, Fengyan; Fan, Xia; Yu, Jing; Ma, Wei; Tang, Wangqi; Yang, Xue; Zhu, Junyu; Kang, Wenyuan; Yan, Jun; Liang, Huaping

2016-01-01

Macrophages are key responders of inflammation and are closely related with oxidative stress. Activated macrophages can enhance oxygen depletion, which causes an overproduction of reactive oxygen species (ROS) and leads to further excessive inflammatory response and tissue damage. Agmatine, an endogenous metabolite of L-arginine, has recently been shown to have neuroprotective effects based on its antioxidant properties. However, the antioxidant effects of agmatine in peripheral tissues and cells, especially macrophages, remain unclear. In this study we explored the role of agmatine in mediating antioxidant effects in RAW 264.7 cells and studied its antioxidant mechanism. Our data demonstrate that agmatine is an activator of Nrf2 signaling that markedly enhances Nrf2 nuclear translocation, increases nuclear Nrf2 protein level, up-regulates the expression of the Nrf2 downstream effector HO-1, and attenuates ROS generation induced by Lipopolysaccharide (LPS). We further demonstrated that the agmatine-induced activation of Nrf2 is likely through the PI3K/Akt pathway. LY294002, a specific PI3K/Akt inhibitor, abolished agmatine-induced HO-1 up-regulation and ROS suppression significantly. Inhibiting HO-1 pathway significantly attenuated the antioxidant effect of agmatine which the products of HO-1 enzymatic activity contributed to. Furthermore, the common membrane receptors of agmatine were evaluated, revealing that α2-adrenoceptor, I1-imidazoline receptor or I2-imidazoline receptor are not required by the antioxidant properties of agmatine. Taken together, our findings revealed that agmatine has antioxidant activity against LPS-induced ROS accumulation in RAW 264.7 cells involving HO-1 expression induced by Nrf2 via PI3K/Akt pathway activation. PMID:27685463

Zurampic Protects Pancreatic β-Cells from High Uric Acid Induced-Damage by Inhibiting URAT1 and Inactivating the ROS/AMPK/ERK Pathways.

PubMed

Xin, Ying; Wang, Kun; Jia, Zhaotong; Xu, Tao; Xu, Qiang; Zhang, Chao; Liu, Jia; Chen, Rui; Du, Zhongcai; Sun, Jianjing

2018-05-25

Zurampic is a US FDA approved drug for treatment of gout. However, the influence of Zurampic on pancreatic β-cells remains unclear. The study aimed to evaluate the effects of Zurampic on high uric acid-induced damage of pancreatic β-cells and the possible underlying mechanisms. INS-1 cells and primary rat islets were stimulated with Zurampic and the mRNA expression of urate transporter 1 (URAT1) was assessed by qRT-PCR. Cells were stimulated with uric acid or uric acid plus Zurampic, and cell viability, apoptosis and ROS release were measured by MTT and flow cytometry assays. Western blot analysis was performed to evaluate the expressions of active Caspase-3 and phosphorylation of AMPK and ERK. Finally, cells were stimulated with uric acid or uric acid plus Zurampic at low/high level of glucose (2.8/16.7 mM glucose), and the insulin release was assessed by ELISA. mRNA expression of URAT1 was decreased by Zurampic in a dose-dependent manner. Uric acid decreased cell viability, promoted cell apoptosis and induced ROS release. Uric acid-induced alterations could be reversed by Zurampic. Activation of Caspase-3 and phosphorylation of AMPK and ERK were enhanced by uric acid, and the enhancements were reversed by Zurampic. Decreased phosphorylation of AMPK and ERK, induced by Zurampic, was further reduced by adding inhibitor of AMPK or ERK. Besides, uric acid inhibited high glucose-induced insulin secretion and the inhibition was rescued by Zurampic. Zurampic has a protective effect on pancreatic β-cells against uric acid induced-damage by inhibiting URAT1 and inactivating the ROS/AMPK/ERK pathway. © 2018 The Author(s). Published by S. Karger AG, Basel.

Escherichia coli Free Radical-Based Killing Mechanism Driven by a Unique Combination of Iron Restriction and Certain Antibiotics

PubMed Central

Ma, Li; Gao, Yongjun

2015-01-01

ABSTRACT Bacterial resistance to antibiotics is precipitating a medical crisis, and new antibacterial strategies are being sought. Hypothesizing that a growth-restricting strategy could be used to enhance the efficacy of antibiotics, we determined the effect of FDA-approved iron chelators and various antibiotic combinations on invasive and multidrug-resistant extraintestinal pathogenic Escherichia coli (ExPEC), the Gram-negative bacterium most frequently isolated from the bloodstreams of hospitalized patients. We report that certain antibiotics used at sublethal concentrations display enhanced growth inhibition and/or killing when combined with the iron chelator deferiprone (DFP). Inductively coupled plasma optical emission spectrometry reveals abnormally high levels of cell-associated iron under these conditions, a response that correlates with an iron starvation response and supraphysiologic levels of reactive oxygen species (ROS). The high ROS level is reversed upon the addition of antioxidants, which restores bacterial growth, suggesting that the cells are inhibited or killed by excessive free radicals. A model is proposed in which peptidoglycan-targeting antibiotics facilitate the entry of lethal levels of iron-complexed DFP into the bacterial cytoplasm, a process that drives the generation of ROS. This new finding suggests that, in addition to restriction of access to iron as a general growth-restricting strategy, targeting of cellular pathways or networks that selectively disrupt normal iron homeostasis can have potent bactericidal outcomes. IMPORTANCE The prospect that common bacteria will become resistant to all antibiotics is challenging the medical community. In addition to the development of next-generation antibiotics, new bacterial targets that display cytotoxic properties when altered need to be identified. Data presented here demonstrate that combining subinhibitory levels of both iron chelators and certain antibiotics kills pathogenic Escherichia coli. The mechanism of this effect is the production of supraphysiologic levels of reactive oxygen species, likely powered by the excessive import of iron. These findings were consistent for both clinically relevant and no longer clinically used antibiotics and may extend to Staphylococcus aureus as well. PMID:26391205

TIGAR contributes to ischemic tolerance induced by cerebral preconditioning through scavenging of reactive oxygen species and inhibition of apoptosis

PubMed Central

Zhou, Jun-Hao; Zhang, Tong-Tong; Song, Dan-Dan; Xia, Yun-Fei; Qin, Zheng-Hong; Sheng, Rui

2016-01-01

Previous study showed that TIGAR (TP53-induced glycolysis and apoptosis regulator) protected ischemic brain injury via enhancing pentose phosphate pathway (PPP) flux and preserving mitochondria function. This study was aimed to study the role of TIGAR in cerebral preconditioning. The ischemic preconditioning (IPC) and isoflurane preconditioning (ISO) models were established in primary cultured cortical neurons and in mice. Both IPC and ISO increased TIGAR expression in cortical neurons. Preconditioning might upregulate TIGAR through SP1 transcription factor. Lentivirus mediated knockdown of TIGAR significantly abolished the ischemic tolerance induced by IPC and ISO. ISO also increased TIGAR in mouse cortex and hippocampus and alleviated subsequent brain ischemia-reperfusion injury, while the ischemic tolerance induced by ISO was eliminated with TIGAR knockdown in mouse brain. ISO increased the production of NADPH and glutathione (GSH), and scavenged reactive oxygen species (ROS), while TIGAR knockdown decreased GSH and NADPH production and increased the level of ROS. Supplementation of ROS scavenger NAC and PPP product NADPH effectively rescue the neuronal injury caused by TIGAR deficiency. Notably, TIGAR knockdown inhibited ISO-induced anti-apoptotic effects in cortical neurons. These results suggest that TIGAR participates in the cerebral preconditioning through reduction of ROS and subsequent cell apoptosis. PMID:27256465

A Novel Mechanism of Mesenchymal Stromal Cell-Mediated Protection against Sepsis: Restricting Inflammasome Activation in Macrophages by Increasing Mitophagy and Decreasing Mitochondrial ROS

PubMed Central

Li, Shuang; Fan, Wensi; Zhang, Ran; Fan, Miaomiao; Huang, Yuesheng

2018-01-01

Sepsis, a systemic inflammatory response to infection, is the leading cause of death in the intensive care unit (ICU). Previous studies indicated that mesenchymal stromal cells (MSCs) might have therapeutic potential against sepsis. The current study was designed to investigate the effects of MSCs on sepsis and the underlying mechanisms focusing on inflammasome activation in macrophages. The results demonstrated that the bone marrow-derived mesenchymal stem cells (BMSCs) significantly increased the survival rate and organ function in cecal ligation and puncture (CLP) mice compared with the control-grouped mice. BMSCs significantly restricted NLRP3 inflammasome activation, suppressed the generation of mitochondrial ROS, and decreased caspase-1 and IL-1β activation when cocultured with bone marrow-derived macrophages (BMDMs), the effects of which could be abolished by Mito-TEMPO. Furthermore, the expression levels of caspase-1, IL-1β, and IL-18 in BMDMs were elevated after treatment with mitophagy inhibitor 3-MA. Thus, BMSCs exert beneficial effects on inhibiting NLRP3 inflammasome activation in macrophages primarily via both enhancing mitophagy and decreasing mitochondrial ROS. These findings suggest that restricting inflammasome activation in macrophages by increasing mitophagy and decreasing mitochondrial ROS might be a crucial mechanism for MSCs to combat sepsis. PMID:29636842

Antioxidant systems in supporting environmental and programmed adaptations to low temperatures.

PubMed

Blagojević, Dusko P

2007-01-01

Hetero and endothermic adaptive responses arising as a result of natural responses to environmental cues include antioxidant systems that support adaptations to environmental low temperatures in the broadest sense. These temperatures induce phase changes in energy production and consequently changes in the concentration of reactive oxygen species (ROS). The latter may lead to oxidative stress and the impairment of cellular homeostasis and antioxidant defence systems (ADS) scavenge the ROS so generated. In endotherms the ADS responds to oxidative pressure during acute cold stress conditions, this response is tissue specific and does not extend to prevent other oxidative damage. The early acute phase of cold exposure is accompanied by a significant depletion in redox equivalents. Under such conditions it is questionable if ADS has the capacity to neutralize elevated levels of ROS since there is also an increased energy demand and enhanced ATP consumption. Prolonged exposure to cold leads to ADS adaptation. Hibernators and freeze-tolerant species elevate their ADS before hibernation or freezing in order to prepare for and cope with re-awakening. The involvement of ROS and the role of the ADS in organisms subjected to low temperatures are features intercalated into physiological mechanisms of homestasis. The exact mechanisms for ADS regulation have not been fully defined and are the subject of many ongoing intriguing scientific investigations.

Knockdown of hepatoma-derived growth factor-related protein-3 induces apoptosis of H1299 cells via ROS-dependent and p53-independent NF-κB activation

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

Yun, Hong Shik; Department of Life Science, College of Natural Sciences, Hanyang University, Seoul 133-791; Baek, Jeong-Hwa

2014-07-11

Highlights: • HRP-3 is a radiation- and anticancer drug-responsive protein in H1299 cells. • Depletion of HRP-3 induces apoptosis of radio- and chemoresistant H1299 cells. • Depletion of HRP-3 promotes ROS generation via inhibition of the Nrf2/HO-1 pathway. • ROS generation enhances NF-κB activity, which acts as an upstream signal in the c-Myc/Noxa apoptotic pathway. - Abstract: We previously identified hepatoma-derived growth factor-related protein-3 (HRP-3) as a radioresistant biomarker in p53 wild-type A549 cells and found that p53-dependent induction of the PUMA pathway was a critical event in regulating the radioresistant phenotype. Here, we found that HRP-3 knockdown regulates themore » radioresistance of p53-null H1299 cells through a distinctly different molecular mechanism. HRP-3 depletion was sufficient to cause apoptosis of H1299 cells by generating substantial levels of reactive oxygen species (ROS) through inhibition of the Nrf2/HO-1 antioxidant pathway. Subsequent, ROS-dependent and p53-independent NF-κB activation stimulated expression of c-Myc and Noxa proteins, thereby inducing the apoptotic machinery. Our results thus extend the range of targets for the development of new drugs to treat both p53 wild-type or p53-null radioresistant lung cancer cells.« less

RbohB, a Phaseolus vulgaris NADPH oxidase gene, enhances symbiosome number, bacteroid size, and nitrogen fixation in nodules and impairs mycorrhizal colonization.

PubMed

Arthikala, Manoj-Kumar; Sánchez-López, Rosana; Nava, Noreide; Santana, Olivia; Cárdenas, Luis; Quinto, Carmen

2014-05-01

The reactive oxygen species (ROS) generated by respiratory burst oxidative homologs (Rbohs) are involved in numerous plant cell signaling processes, and have critical roles in the symbiosis between legumes and nitrogen-fixing bacteria. Previously, down-regulation of RbohB in Phaseolus vulgaris was shown to suppress ROS production and abolish Rhizobium infection thread (IT) progression, but also to enhance arbuscular mycorrhizal fungal (AMF) colonization. Thus, Rbohs function both as positive and negative regulators. Here, we assessed the effect of enhancing ROS concentrations, by overexpressing PvRbohB, on the P. vulgaris--rhizobia and P. vulgaris--AMF symbioses. We estimated superoxide concentrations in hairy roots overexpressing PvRbohB, determined the status of early and late events of both Rhizobium and AMF interactions in symbiont-inoculated roots, and analyzed the nodule ultrastructure of transgenic plants overexpressing PvRbohB. Overexpression of PvRbohB significantly enhanced ROS production, the formation of ITs, nodule biomass, and nitrogen-fixing activity, and increased the density of symbiosomes in nodules, and the density and size of bacteroides in symbiosomes. Furthermore, PvCAT, early nodulin, PvSS1, and PvGOGAT transcript abundances were elevated in these nodules. By contrast, mycorrhizal colonization was reduced in roots that overexpressed RbohB. Overexpression of PvRbohB augmented nodule efficiency by enhancing nitrogen fixation and delaying nodule senescence, but impaired AMF colonization. © 2014 The Authors. New Phytologist © 2014 New Phytologist Trust.

Enhancing Tumor Drug Delivery by Laser-Activated Vascular Barrier Disruption

DTIC Science & Technology

2006-12-01

increased, which leads to normal tissue toxicity . This delivery problem not only limits the clinical application of existing chemotherapeutics, but also...principles and uses photochemical reactions to generate biological effectors, such as reactive oxygen species (ROS), which cause oxidative damage to...liposomes, mi- celles, and biodegradable nanoparticles , or conju- gated with hydrophilic polymers.6 It is likely that although some level of

High level of chromosomal instability in circulating tumor cells of ROS1-rearranged non-small-cell lung cancer

PubMed Central

Pailler, E.; Auger, N.; Lindsay, C. R.; Vielh, P.; Islas-Morris-Hernandez, A.; Borget, I.; Ngo-Camus, M.; Planchard, D.; Soria, J.-C.; Besse, B.; Farace, F.

2015-01-01

Background Genetic aberrations affecting the c-ros oncogene 1 (ROS1) tyrosine kinase gene have been reported in a small subset of patients with non-small-cell lung cancer (NSCLC). We evaluated whether ROS1-chromosomal rearrangements could be detected in circulating tumor cells (CTCs) and examined tumor heterogeneity of CTCs and tumor biopsies in ROS1-rearranged NSCLC patients. Patients and methods Using isolation by size of epithelial tumor cells (ISET) filtration and filter-adapted-fluorescence in situ hybridization (FA-FISH), ROS1 rearrangement was examined in CTCs from four ROS1-rearranged patients treated with the ROS1-inhibitor, crizotinib, and four ROS1-negative patients. ROS1-gene alterations observed in CTCs at baseline from ROS1-rearranged patients were compared with those present in tumor biopsies and in CTCs during crizotinib treatment. Numerical chromosomal instability (CIN) of CTCs was assessed by DNA content quantification and chromosome enumeration. Results ROS1 rearrangement was detected in the CTCs of all four patients with ROS1 rearrangement previously confirmed by tumor biopsy. In ROS1-rearranged patients, median number of ROS1-rearranged CTCs at baseline was 34.5 per 3 ml blood (range, 24–55). In ROS1-negative patients, median background hybridization of ROS1-rearranged CTCs was 7.5 per 3 ml blood (range, 7–11). Tumor heterogeneity, assessed by ROS1 copy number, was significantly higher in baseline CTCs compared with paired tumor biopsies in the three patients experiencing PR or SD (P < 0.0001). Copy number in ROS1-rearranged CTCs increased significantly in two patients who progressed during crizotinib treatment (P < 0.02). CTCs from ROS1-rearranged patients had a high DNA content and gain of chromosomes, indicating high levels of aneuploidy and numerical CIN. Conclusion We provide the first proof-of-concept that CTCs can be used for noninvasive and sensitive detection of ROS1 rearrangement in NSCLC patients. CTCs from ROS1-rearranged patients show considerable heterogeneity of ROS1-gene abnormalities and elevated numerical CIN, a potential mechanism to escape ROS1-inhibitor therapy in ROS1-rearranged NSCLC tumors. PMID:25846554

Blue light irradiation-induced oxidative stress in vivo via ROS generation in rat gingival tissue.

PubMed

Yoshida, Ayaka; Shiotsu-Ogura, Yukako; Wada-Takahashi, Satoko; Takahashi, Shun-suke; Toyama, Toshizo; Yoshino, Fumihiko

2015-10-01

It has been reported that oxidative stress with reactive oxygen species (ROS) generation is induced by blue light irradiation to a living body. Only limited research has been reported in dental field on the dangers of blue light, mostly focusing on cytotoxicity associated with heat injury of dental pulp. We thus performed an in vivo study on oral tissue exposed to blue light. ROS generated upon blue light irradiation of flavin adenine dinucleotide were measured by electron spin resonance spectroscopy. After blue light irradiation, the palatal gingiva of Wistar rats were isolated. Collected samples were subjected to biochemical analysis of lipid peroxidation and glutathione. Singlet oxygen was generated by blue light irradiation, but was significantly quenched in an N-acetyl-L-cysteine (NAC) concentration-dependent manner. Blue light significantly accelerated oxidative stress and increased the oxidized glutathione levels in gingival tissue. These effects were also inhibited by NAC pre-administration. The results suggest that blue light irradiation at clinical levels of tooth bleaching treatment may enhance lipid peroxidation by the induction of oxidative stress and the consumption of a significant amount of intracellular glutathione. In addition, NAC might be an effective supplement for the protection of oral tissues against blue light irradiation-induced oxidative damage. Copyright © 2015 Elsevier B.V. All rights reserved.

Ergothioneine prevents endothelial dysfunction induced by mercury chloride.

PubMed

Gökçe, Göksel; Arun, Mehmet Zuhuri; Ertuna, Elif

2018-06-01

Exposure to mercury has detrimental effects on the cardiovascular system, particularly the vascular endothelium. The present study aimed to investigate the effects of ergothioneine (EGT) on endothelial dysfunction induced by low-dose mercury chloride (HgCl 2 ). Agonist-induced contractions and relaxations were evaluated in isolated aortic rings from 3-month-old male Wistar rats treated by intra-muscular injection to caudal hind leg muscle with HgCl 2 (first dose, 4.6 µg/kg; subsequent doses, 0.07 µg/kg/day for 15 days) and optionally with EGT (2 µg/kg for 30 days). Reactive oxygen species (ROS) in aortic rings were measured by means of lucigenin- and luminol-enhanced chemiluminescence. The protein level of endothelial nitric oxide synthase was evaluated by ELISA. Blood glutathione (GSH) and catalase levels, lipid peroxidation and total nitrite were measured spectrophotometrically. The results indicated that low-dose HgCl 2 administration impaired acetylcholine (ACh)-induced relaxation and potentiated phenylephrine- and serotonin-induced contractions in rat aortas. In addition, HgCl 2 significantly increased the levels of ROS in the aortic tissue. EGT prevented the loss of ACh-induced relaxations and the increase in contractile responses. These effects were accompanied by a significant decrease in ROS levels. EGT also improved the ratio of reduced GSH to oxidized GSH and catalase levels with a concomitant decrease in lipid peroxidation. In conclusion, to the best of our knowledge, the present study was the first to report that EGT prevents endothelial dysfunction induced by low-dose HgCl 2 administration. EGT may serve as a therapeutic tool to reduce mercury-associated cardiovascular complications via improving the antioxidant status.

Glaucarubinone sensitizes KB cells to paclitaxel by inhibiting ABC transporters via ROS-dependent and p53-mediated activation of apoptotic signaling pathways

PubMed Central

Karthikeyan, Subburayan; Hoti, Sugeerappa Laxmanappa; Nazeer, Yasin; Hegde, Harsha Vasudev

2016-01-01

Multidrug resistance (MDR) is considered to be the major contributor to failure of chemotherapy in oral squamous cell carcinoma (SCC). This study was aimed to explore the effects and mechanisms of glaucarubinone (GLU), one of the major quassinoids from Simarouba glauca DC, in potentiating cytotoxicity of paclitaxel (PTX), an anticancer drug in KB cells. Our data showed that the administration of GLU pre-treatment significantly enhanced PTX anti-proliferative effect in ABCB1 over-expressing KB cells. The Rh 123 drug efflux studies revealed that there was a significant transport function inhibition by GLU-PTX treatment. Interestingly, it was also found that this enhanced anticancer efficacy of GLU was associated with PTX-induced cell arrest in the G2/M phase of cell cycle. Further, the combined treatment of GLU-PTX had significant decrease in the expression levels of P-gp, MRPs, and BCRP in resistant KB cells at both mRNA and protein levels. Furthermore, the combination treatments showed significant reactive oxygen species (ROS) production, chromatin condensation and reduced mitochondrial membrane potential in resistant KB cells. The results from DNA fragmentation analysis also demonstrated the GLU induced apoptosis in KB cells and its synergy with PTX. Importantly, GLU and/or PTX triggered apoptosis through the activation of pro-apoptotic proteins such as p53, Bax, and caspase-9. Our findings demonstrated for the first time that GLU causes cell death in human oral cancer cells via the ROS-dependent suppression of MDR transporters and p53-mediated activation of the intrinsic mitochondrial pathway of apoptosis. Additionally, the present study also focussed on investigation of the protective effect of GLU and combination drugs in human normal blood lymphocytes. Normal blood lymphocytes assay indicated that GLU is able to induce selective toxicity in cancer cells and in silico molecular docking studies support the choice of GLU as ABC inhibitor to enhance PTX efficacy. Thus, GLU has the potential to enhance the activity of PTX and hence can be a good alternate treatment strategy for the reversal of PTX resistance. PMID:27304668

Mitochondrial and Cytoplasmic ROS Have Opposing Effects on Lifespan

PubMed Central

Schaar, Claire E.; Dues, Dylan J.; Spielbauer, Katie K.; Machiela, Emily; Cooper, Jason F.; Senchuk, Megan; Hekimi, Siegfried; Van Raamsdonk, Jeremy M.

2015-01-01

Reactive oxygen species (ROS) are highly reactive, oxygen-containing molecules that can cause molecular damage within the cell. While the accumulation of ROS-mediated damage is widely believed to be one of the main causes of aging, ROS also act in signaling pathways. Recent work has demonstrated that increasing levels of superoxide, one form of ROS, through treatment with paraquat, results in increased lifespan. Interestingly, treatment with paraquat robustly increases the already long lifespan of the clk-1 mitochondrial mutant, but not other long-lived mitochondrial mutants such as isp-1 or nuo-6. To genetically dissect the subcellular compartment in which elevated ROS act to increase lifespan, we deleted individual superoxide dismutase (sod) genes in clk-1 mutants, which are sensitized to ROS. We find that only deletion of the primary mitochondrial sod gene, sod-2 results in increased lifespan in clk-1 worms. In contrast, deletion of either of the two cytoplasmic sod genes, sod-1 or sod-5, significantly decreases the lifespan of clk-1 worms. Further, we show that increasing mitochondrial superoxide levels through deletion of sod-2 or treatment with paraquat can still increase lifespan in clk-1;sod-1 double mutants, which live shorter than clk-1 worms. The fact that mitochondrial superoxide can increase lifespan in worms with a detrimental level of cytoplasmic superoxide demonstrates that ROS have a compartment specific effect on lifespan – elevated ROS in the mitochondria acts to increase lifespan, while elevated ROS in the cytoplasm decreases lifespan. This work also suggests that both ROS-dependent and ROS-independent mechanisms contribute to the longevity of clk-1 worms. PMID:25671321

Reactive Oxygen Species and Oxidative Stress in Obesity-Recent Findings and Empirical Approaches.

PubMed

McMurray, Fiona; Patten, David A; Harper, Mary-Ellen

2016-11-01

High levels of reactive oxygen species (ROS) are intricately linked to obesity and associated pathologies, notably insulin resistance and type 2 diabetes. However, ROS are also thought to be important in intracellular signaling, which may paradoxically be required for insulin sensitivity. Many theories have been developed to explain this apparent paradox, which have broadened our understanding of these important small molecules. While many sites for intracellular ROS production have been described, mitochondrial generated ROS remain a major contributor in most cell types. Mitochondrial ROS generation is controlled by a number of factors described in this review. Moreover, these studies have established both a demand for novel sensitive approaches to measure ROS, as well as a need to standardize and review their suitability for different applications. To properly assess levels of ROS and mitochondrial ROS in the development of obesity and its complications, a growing number of tools have been developed. This paper reviews many of the common methods for the investigation of ROS in mitochondria, cell, animal, and human models. Available approaches can be generally divided into those that measure ROS-induced damage (e.g., DNA, lipid, and protein damage); those that measure antioxidant levels and redox ratios; and those that use novel biosensors and probes for a more direct measure of different forms of ROS (e.g., 2',7'-di-chlorofluorescein (DCF), dihydroethidium (DHE) and its mitochondrial targeted form (MitoSOX), Amplex Red, roGFP, HyPer, mt-cpYFP, ratiometric H 2 O 2 probes, and their derivatives). Moreover, this review provides caveats and strengths for the use of these techniques in different models. Advances in these techniques will undoubtedly advance the understanding of ROS in obesity and may help resolve unanswered questions in the field. © 2016 The Obesity Society.

Autophagy protects chondrocytes from glucocorticoids-induced apoptosis via ROS/Akt/FOXO3 signaling.

PubMed

Shen, C; Cai, G-Q; Peng, J-P; Chen, X-D

2015-12-01

Glucocorticoids (GCs) have been widely used in the management of osteoarthritis (OA) and rheumatoid arthritis (RA). Nevertheless, there has been some concern about their ability of increasing reactive oxygen species (ROS) in the cartilage. Forkhead-box class O (FOXO) transcription factors have been proved to have a protective role in chondrocytes through regulation of autophagy and defending oxidative stress. The objective of this study was to investigate the role of FOXO3 in Dex-induce up-regulation of ROS. Healthy cartilages debris from six patients were used for chondrocytes culture. After the treatment of dexamethasone (Dex), the ROS levels, autophagic flux, the expression of FOXO3 in chondrocytes were measured. RNA interference technique was also used to determine the role of FOXO3 in Dex-induced autophagy. The metabolism of the extra-cellular matrix was also investigated. Dex increased intracellular ROS level, the expression of Akt, FOXO3 as well as autophagy flux in human chondrocytes. The expression of aggrecanases also increased after the treatment of Dex. Catalase, the ROS scavenger, suppressed Dex-induced up-regulation of autophagy flux and expression of aggrecanases and Akt. MK-2206 and LY294002, the PI3K/Akt inhibitors, repressed Dex-induced up-regulation of FOXO3. Silencing FOXO3 resulted in down-regulation of Dex-induced autophagy. Moreover, knockdown of FOXO3 increased Dex-induced apoptosis as well as ROS levels in chondrocytes. In addition, up-regulation of autophagy by Rapamycin resulted in decreasing ROS level in chondrocytes. Dex could advance the degenerative process in cartilage. Autophagy was induced in response to Dex-induced up-regulation of ROS via ROS/Akt/FOXO3 signal pathway. Copyright © 2015 Osteoarthritis Research Society International. Published by Elsevier Ltd. All rights reserved.

ROS Produced by NOX2 Controls In Vitro Development of Cerebellar Granule Neurons Development

PubMed Central

Olguín-Albuerne, Mauricio

2015-01-01

Reactive oxygen species (ROS) act as signaling molecules that regulate nervous system physiology. ROS have been related to neural differentiation, neuritogenesis, and programmed cell death. Nevertheless, little is known about the mechanisms involved in the regulation of ROS during neuronal development. In this study, we evaluated the mechanisms by which ROS are regulated during neuronal development and the implications of these molecules in this process. Primary cultures of cerebellar granule neurons (CGN) were used to address these issues. Our results show that during the first 3 days of CGN development in vitro (days in vitro; DIV), the levels of ROS increased, reaching a peak at 2 and 3 DIV under depolarizing (25 mM KCl) and nondepolarizing (5 mM KCl) conditions. Subsequently, under depolarizing conditions, the ROS levels markedly decreased, but in nondepolarizing conditions, the ROS levels increased gradually. This correlated with the extent of CGN maturation. Also, antioxidants and NADPH-oxidases (NOX) inhibitors reduced the expression of Tau and MAP2. On the other hand, the levels of glutathione markedly increased at 1 DIV. We inferred that the ROS increase at this time is critical for cell survival because glutathione depletion leads to axonal degeneration and CGN death only at 2 DIV. During the first 3 DIV, NOX2 was upregulated and expressed in filopodia and growth cones, which correlated with the hydrogen peroxide (H2O2) distribution in the cell. Finally, NOX2 KO CGN showed shorter neurites than wild-type CGN. Taken together, these results suggest that the regulation of ROS is critical during the early stages of CGN development. PMID:25873309

Curcuminoid EF24 enhances the anti-tumour activity of Akt inhibitor MK-2206 through ROS-mediated endoplasmic reticulum stress and mitochondrial dysfunction in gastric cancer.

PubMed

Chen, Xi; Dai, Xuanxuan; Zou, Peng; Chen, Weiqian; Rajamanickam, Vinothkumar; Feng, Chen; Zhuge, Weishan; Qiu, Chenyu; Ye, Qingqing; Zhang, Xiaohua; Liang, Guang

2017-05-01

Gastric cancer is one of the leading causes of morbidity and mortality worldwide. Akt is an anti-apoptotic kinase that plays a dynamic role in cell survival and is implicated in the pathogenesis of gastric cancer. MK-2206, the first allosteric inhibitor of Akt, is in clinical trials for a number of cancers. Although preclinical studies showed promise, clinical trials reported it had no effect when given alone at tolerated doses. The aim of our study was to delineate the effects of MK-2206 on gastric cancer cells and explore the ability of combination treatments to enhance the anti-tumour activity of MK-2206. SGC-7901, BGC-823 cells and immunodeficient mice were chosen as a model to study the treatment effects. Changes in cell viability, apoptosis and ROS, endoplasmic reticulum stress and mitochondrial dysfunction in the cells were analysed by MTT assays, ROS imaging and FACSCalibur, electron microscopy, JC-1 staining and western blotting. MK-2206 induced apoptotic cell death through the generation of ROS. We utilized ROS production to target gastric cancer cells by combining MK-2206 and an ROS inducer EF24. Our in vitro and in vivo xenograft studies showed that combined treatment with MK-2206 and EF24 synergistically induced apoptosis in gastric cancer cells and caused cell cycle arrest. These activities were mediated through ROS generation and the induction of endoplasmic reticulum stress and mitochondrial dysfunction. Targeting ROS generation by using a combination of an Akt inhibitor and EF24 could have potential as a therapy for gastric cancer. © 2017 The British Pharmacological Society.

Oxidative stress provokes distinct transcriptional responses in the stress-tolerant atr7 and stress-sensitive loh2 Arabidopsis thaliana mutants as revealed by multi-parallel quantitative real-time PCR analysis of ROS marker and antioxidant genes.

PubMed

Mehterov, Nikolay; Balazadeh, Salma; Hille, Jacques; Toneva, Valentina; Mueller-Roeber, Bernd; Gechev, Tsanko

2012-10-01

The Arabidopsis thaliana atr7 mutant is tolerant to oxidative stress induced by paraquat (PQ) or the catalase inhibitor aminotriazole (AT), while its original background loh2 and wild-type plants are sensitive. Both, AT and PQ, which stimulate the intracellular formation of H₂O₂ or superoxide anions, respectively, trigger cell death in loh2 but do not lead to visible damage in atr7. To study gene expression during oxidative stress and ROS-induced programmed cell death, two platforms for multi-parallel quantitative real-time PCR (qRT-PCR) analysis of 217 antioxidant and 180 ROS marker genes were employed. The qRT-PCR analyses revealed AT- and PQ-induced expression of many ROS-responsive genes mainly in loh2, confirming that an oxidative burst plays a role in the activation of the cell death in this mutant. Some of the genes were specifically regulated by either AT or PQ, serving as markers for particular types of ROS. Genes significantly induced by both AT and PQ in loh2 included transcription factors (ANAC042/JUB1, ANAC102, DREB19, HSFA2, RRTF1, ZAT10, ZAT12, ethylene-responsive factors), signaling compounds, ferritins, alternative oxidases, and antioxidant enzymes. Many of these genes were upregulated in atr7 compared to loh2 under non-stress conditions at the first time point, indicating that higher basal levels of ROS and higher antioxidant capacity in atr7 are responsible for the enhanced tolerance to oxidative stress and suggesting a possible tolerance against multiple stresses of this mutant. Copyright © 2012 Elsevier Masson SAS. All rights reserved.

Micro-encapsulated sensors for in vivo assessment of the oxidative stress in aquatic organisms

NASA Astrophysics Data System (ADS)

Sadovoy, Anton; Teh, Cathleen; Escobar, Marco; Meglinski, Igor; Korzh, Vladimir

2011-10-01

Oxidative stress results from an imbalance between the production and detoxification of reactive oxygen spices (ROS). ROS are natural byproducts of normal metabolism of oxygen and have important roles in cell signaling and homeostasis. Many heart related diseases like heart failure and myocardial infarction develop as a result of oxidative stress. Current treatment cannot improve the progressive decline in heart function experienced by all patients. Therefore heart failure is the cause of around 25% of all deaths in the Asia Pacific region. Thus any step taken to address the oxidative stress problem is essential for enhancing human health and improve their quality of life. Current approach is dedicated to develop micron-size oxidation stress-sensor for in-vivo measuring level of ROS in KillerRed expressing transgenic zebrafish larvae. Central to our investigation is the light-inducible heart failure animal model we developed in zebrafish that expressed KillerRed in the heart. By utilizing the photosensitizer properties of KillerRed to produce ROS upon green light illumination, heart failure can be repeatedly induced in a non-invasive manner. Importantly, the use of this biological platform permits the development of physiologically sensitive ROS sensor and identifies efficient antioxidants that improve heart contractility. The biosensor approach is based on utilizing biocompatible polyelectrolyte microcapsules as a carry of fluorescent dyes sensitive to amount of reactive oxygen spices. Microcapsule prevents dye diffusion in tissue that makes use toxic dyes possible. Microcapsule's wall is permeable for environment with size less than 500 Da. The oxidation stress-sensors are injected directly in zebrafish pericardium with further circulation along blood system. Detecting of ROS is obtained by using laser scanning microscopy by illuminating oxidation stress-sensors and detecting changing excitation signal from the fluorescent dye.

Micro-encapsulated sensors for in vivo assessment of the oxidative stress in aquatic organisms

NASA Astrophysics Data System (ADS)

Sadovoy, Anton; Teh, Cathleen; Escobar, Marco; Meglinski, Igor; Korzh, Vladimir

2012-03-01

Oxidative stress results from an imbalance between the production and detoxification of reactive oxygen spices (ROS). ROS are natural byproducts of normal metabolism of oxygen and have important roles in cell signaling and homeostasis. Many heart related diseases like heart failure and myocardial infarction develop as a result of oxidative stress. Current treatment cannot improve the progressive decline in heart function experienced by all patients. Therefore heart failure is the cause of around 25% of all deaths in the Asia Pacific region. Thus any step taken to address the oxidative stress problem is essential for enhancing human health and improve their quality of life. Current approach is dedicated to develop micron-size oxidation stress-sensor for in-vivo measuring level of ROS in KillerRed expressing transgenic zebrafish larvae. Central to our investigation is the light-inducible heart failure animal model we developed in zebrafish that expressed KillerRed in the heart. By utilizing the photosensitizer properties of KillerRed to produce ROS upon green light illumination, heart failure can be repeatedly induced in a non-invasive manner. Importantly, the use of this biological platform permits the development of physiologically sensitive ROS sensor and identifies efficient antioxidants that improve heart contractility. The biosensor approach is based on utilizing biocompatible polyelectrolyte microcapsules as a carry of fluorescent dyes sensitive to amount of reactive oxygen spices. Microcapsule prevents dye diffusion in tissue that makes use toxic dyes possible. Microcapsule's wall is permeable for environment with size less than 500 Da. The oxidation stress-sensors are injected directly in zebrafish pericardium with further circulation along blood system. Detecting of ROS is obtained by using laser scanning microscopy by illuminating oxidation stress-sensors and detecting changing excitation signal from the fluorescent dye.

Lipid peroxidation and apoptotic response in rat brain areas induced by long-term administration of nandrolone: the mutual crosstalk between ROS and NF-kB.

PubMed

Turillazzi, Emanuela; Neri, Margherita; Cerretani, Daniela; Cantatore, Santina; Frati, Paola; Moltoni, Laura; Busardò, Francesco Paolo; Pomara, Cristoforo; Riezzo, Irene; Fineschi, Vittorio

2016-04-01

The aim of this study was to evaluate the played by oxidative stress in the apoptotic response in different brain areas of rats chronically treated with supra-physiological doses of nandrolone decanoate (ND). Immunohistochemical study and Western blot analysis were performed to evaluate cells' apoptosis and to measure the effects of expression of specific mediators, such as NF-κB (nuclear factor kappa-light-chain-enhancer of activated B cells), Bcl-2 (B-cell lymphoma 2), SMAC/DIABLO (second mitochondria-derived activator of caspases/direct IAP-binding protein with low PI) and VMAT2 (vesicular monoamine transporter 2) on apoptosis. The results of the present study indicate that a long-term administration of ND promotes oxidative injury in rat brain specific areas. A link between oxidative stress and NF-κB signalling pathways is supported by our results. In addition to high levels of oxidative stress, we consistently observed a strong immunopositivity to NF-κB. It has been argued that one of the pathways leading to the activation of NF-κB could be under reactive oxygen species (ROS)-mediated control. In fact, growing evidence suggests that although in limited doses, endogenous ROS may play an activating role in NF-κB signalling, while above a certain threshold, they may negatively impact upon this signalling. However, a mutual crosstalk between ROS and NF-κB exists and recent studies have shown that ROS activity is subject to negative feedback regulation by NF-κB, and that this negative regulation of ROS is the means through which NF-κB counters programmed cells. © 2016 The Authors. Journal of Cellular and Molecular Medicine published by John Wiley & Sons Ltd and Foundation for Cellular and Molecular Medicine.

Oxalate-curcumin-based probe for micro- and macroimaging of reactive oxygen species in Alzheimer's disease.

PubMed

Yang, Jian; Zhang, Xueli; Yuan, Peng; Yang, Jing; Xu, Yungen; Grutzendler, Jaime; Shao, Yihan; Moore, Anna; Ran, Chongzhao

2017-11-21

Alzheimer's disease (AD) is an irreversible neurodegenerative disorder that has a progression that is closely associated with oxidative stress. It has long been speculated that the reactive oxygen species (ROS) level in AD brains is much higher than that in healthy brains. However, evidence from living beings is scarce. Inspired by the "chemistry of glow stick," we designed a near-IR fluorescence (NIRF) imaging probe, termed CRANAD-61, for sensing ROS to provide evidence at micro- and macrolevels. In CRANAD-61, an oxalate moiety was utilized to react with ROS and to consequentially produce wavelength shifting. Our in vitro data showed that CRANAD-61 was highly sensitive and rapidly responsive to various ROS. On reacting with ROS, its excitation and emission wavelengths significantly shifted to short wavelengths, and this shifting could be harnessed for dual-color two-photon imaging and transformative NIRF imaging. In this report, we showed that CRANAD-61 could be used to identify "active" amyloid beta (Aβ) plaques and cerebral amyloid angiopathy (CAA) surrounded by high ROS levels with two-photon imaging (microlevel) and to provide relative total ROS concentrations in AD brains via whole-brain NIRF imaging (macrolevel). Lastly, we showed that age-related increases in ROS levels in AD brains could be monitored with our NIRF imaging method. We believe that our imaging with CRANAD-61 could provide evidence of ROS at micro- and macrolevels and could be used for monitoring ROS changes under various AD pathological conditions and during drug treatment.

Oxidative Stress Markers Correlate with Renal Dysfunction and Thrombocytopenia in Severe Leptospirosis

PubMed Central

Araújo, Alan M.; Reis, Eliana A. G.; Athanazio, Daniel A.; Ribeiro, Guilherme S.; Hagan, José E.; Araujo, Guilherme C.; Damião, Alcineia O.; Couto, Nicolli S.; Ko, Albert I.; Noronha-Dutra, Alberto; Reis, Mitermayer G.

2014-01-01

Leptospirosis is a zoonotic disease that causes severe manifestations such as Weil's disease and pulmonary hemorrhage syndrome. The aim of this study was to evaluate whether reactive oxygen species (ROS) production and antioxidant reduced glutathione (GSH) levels are related to complications in patients hospitalized with leptospirosis. The ROS production and GSH levels were measured in blood samples of 12 patients and nine healthy controls using chemiluminescence and absorbance assays. We found that ROS production was higher and GSH levels were lower in leptospirosis patients compared with healthy individuals. Among patients, GSH depletion was correlated with thrombocytopenia and elevated serum creatinine, whereas a strong positive correlation was observed between ROS production and elevated serum potassium. Additional investigation of the biological significance of ROS production and GSH levels is warranted as they may guide the development of novel adjuvant therapies for leptospirosis targeting oxidative stress. PMID:24493675

Manganese ions enhance mitochondrial H2O2 emission from Krebs cycle oxidoreductases by inducing permeability transition.

PubMed

Bonke, Erik; Siebels, Ilka; Zwicker, Klaus; Dröse, Stefan

2016-10-01

Manganese-induced toxicity has been linked to mitochondrial dysfunction and an increased generation of reactive oxygen species (ROS). We could recently show in mechanistic studies that Mn 2+ ions induce hydrogen peroxide (H 2 O 2 ) production from the ubiquinone binding site of mitochondrial complex II (II Q ) and generally enhance H 2 O 2 formation by accelerating the rate of superoxide dismutation. The present study with intact mitochondria reveals that manganese additionally enhances H 2 O 2 emission by inducing mitochondrial permeability transition (mPT). In mitochondria fed by NADH-generating substrates, the combination of Mn 2+ and different respiratory chain inhibitors led to a dynamically increasing H 2 O 2 emission which was sensitive to the mPT inhibitor cyclosporine A (CsA) as well as Ru-360, an inhibitor of the mitochondrial calcium uniporter (MCU). Under these conditions, flavin-containing enzymes of the mitochondrial matrix, e.g. the mitochondrial 2-oxoglutaratedehydrogenase (OGDH), were major sources of ROS. With succinate as substrate, Mn 2+ stimulated ROS production mainly at complex II, whereby the applied succinate concentration had a marked effect on the tendency for mPT. Also Ca 2+ increased the rate of H 2 O 2 emission by mPT, while no direct effect on ROS-production of complex II was observed. The present study reveals a complex scenario through which manganese affects mitochondrial H 2 O 2 emission: stimulating its production from distinct sites (e.g. site II Q ), accelerating superoxide dismutation and enhancing the emission via mPT which also leads to the loss of soluble components of the mitochondrial antioxidant systems and favors the ROS production from flavin-containing oxidoreductases of the Krebs cycle. Copyright © 2016 Elsevier Inc. All rights reserved.

Hemoglobin fructation promotes heme degradation through the generation of endogenous reactive oxygen species

NASA Astrophysics Data System (ADS)

Goodarzi, M.; Moosavi-Movahedi, A. A.; Habibi-Rezaei, M.; Shourian, M.; Ghourchian, H.; Ahmad, F.; Farhadi, M.; Saboury, A. A.; Sheibani, N.

2014-09-01

Protein glycation is a cascade of nonenzymatic reactions between reducing sugars and amino groups of proteins. It is referred to as fructation when the reducing monosaccharide is fructose. Some potential mechanisms have been suggested for the generation of reactive oxygen species (ROS) by protein glycation reactions in the presence of glucose. In this state, glucose autoxidation, ketoamine, and oxidative advance glycation end products (AGEs) formation are considered as major sources of ROS and perhaps heme degradation during hemoglobin glycation. However, whether fructose mediated glycation produces ROS and heme degradation is unknown. Here we report that ROS (H2O2) production occurred during hemoglobin fructation in vitro using chemiluminescence methods. The enhanced heme exposure and degradation were determined using UV-Vis and fluorescence spectrophotometry. Following accumulation of ROS, heme degradation products were accumulated reaching a plateau along with the detected ROS. Thus, fructose may make a significant contribution to the production of ROS, glycation of proteins, and heme degradation during diabetes.

Cells redox environment modulates BRCA1 expression and DNA homologous recombination repair.

PubMed

Wilson, Aaron; Yakovlev, Vasily A

2016-12-01

Cancer development and progression have been linked to oxidative stress, a condition characterized by unbalanced increase in ROS and RNS production. The main endogenous initiators of the redox imbalance in cancer cells are defective mitochondria, elevated NOX activity, and uncoupled NOS3. Traditionally, most attention has been paid to direct oxidative damage to DNA by certain ROS. However, increase in oxidative DNA lesions does not always lead to malignancy. Hence, additional ROS-dependent, pro-carcinogenic mechanisms must be important. Our recent study demonstrated that Tyr nitration of PP2A stimulates its activity and leads to downregulation of BRCA1 expression. This provides a mechanism for chromosomal instability essential for tumor progression. In the present work, we demonstrated that inhibition of ROS production by generating mitochondrial-electron-transport-deficient cell lines (ρ 0 cells) or by inhibition of NOX activity with a selective peptide inhibitor significantly reduced PP2A Tyr nitration and its activity in different cancer cell lines. As a result of the decreased PP2A activity, BRCA1 expression was restored along with a significantly enhanced level of DNA HRR. We used TCGA database to analyze the correlation between expressions of the NOX regulatory subunits, NOS isoforms, and BRCA1 in the 3 cancer research studies: breast invasive carcinoma, ovarian cystadenocarcinoma, and lung adenocarcinoma. TCGA database analysis demonstrated that the high expression levels of most of the NOX regulatory subunits responsible for stimulation of NOX1-NOX4 were associated with significant downregulation of BRCA1 expression. Copyright © 2016. Published by Elsevier Inc.

Retigeric acid B exerts antifungal effect through enhanced reactive oxygen species and decreased cAMP.

PubMed

Chang, Wen-Qiang; Wu, Xiu-Zhen; Cheng, Ai-Xia; Zhang, Li; Ji, Mei; Lou, Hong-Xiang

2011-05-01

Retigeric acid B (RAB), a triterpene acid isolated from Lobaria kurokawae exerts antifungal effect. The present study was designed to elucidate the underlying mechanisms by which RAB regulates the proliferation and cell death of Candida albicans. We measured the metabolic activity of C. albicans with WST1 Cell Proliferation and Cytotoxicity Assay Kit, analyzed the cell cycle by flow cytometry, visualized the ultrastructure by transmission electron microscopy (TEM) and investigated the apoptosis and necrosis induced by RAB using confocal microscopy. The reactive oxygen species (ROS) accumulation was determined by spectrophotometry, flow cytometry and fluorescent microscopy. The mtΔψ was detected using flow cytometry. And the levels of intracellular cAMP and ATP were measured with cAMP ELISA and ATP Assay Kits, respectively. The proliferation of the yeasts was blocked in G(2)/M phase by a low dose of RAB treatment and in G(1) phase at high concentration. When cultured in phosphate buffered saline (PBS) deprived of energy source, yeasts displayed the phenotype of death caused by accumulated ROS, mtΔψ hyperpolarization and dramatic decrease in ATP level in the presence of high dose of RAB. RAB inhibits the growth of C. albicans by stimulating ROS production and reducing intracellular cAMP. The ROS accumulation, mtΔψ hyperpolarization, ATP depletion and damaged plasma membrane integrity together mediate cell death of C. albicans induced by RAB. Our findings provide a novel molecular mechanism for exploring possible applications of lichen derived metabolites in fighting fungal infection in humans. Copyright © 2011 Elsevier B.V. All rights reserved.

Direct exposure to mild heat promotes proliferation and neuronal differentiation of neural stem/progenitor cells in vitro

PubMed Central

Hossain, Md Emon; Katakura, Masanori; Sugimoto, Naotoshi; Mamun, Abdullah Al; Islam, Rafiad; Hashimoto, Michio; Shido, Osamu

2017-01-01

Heat acclimation in rats is associated with enhanced neurogenesis in thermoregulatory centers of the hypothalamus. To elucidate the mechanisms for heat acclimation, we investigated the effects of direct mild heat exposure on the proliferation and differentiation of neural stem/progenitor cells (NSCs/NPCs). The NSCs/NPCs isolated from forebrain cortices of 14.5-day-old rat fetuses were propagated as neurospheres at either 37.0°C (control) or 38.5°C (mild heat exposure) for four days, and the effects on proliferation were investigated by MTS cell viability assay, measurement of neurosphere diameter, and counting the total number of cells. The mRNA expressions of heat shock proteins (HSPs) and brain-derived neurotrophic factor (BDNF), cAMP response element-binding (CREB) protein and Akt phosphorylation levels, and intracellular reactive oxygen species (ROS) levels were analyzed using real time PCR, Western blotting and CM-H2DCFDA assay respectively. Heat exposure under proliferation condition increased NSC/NPC viability, neurosphere diameter, and cell count. BDNF mRNA expression, CREB phosphorylation, and ROS level were also increased by heat exposure. Heat exposure increased HSP27 mRNA expression concomitant with enhanced p-Akt level. Moreover, treatment with LY294002 (a PI3K inhibitor) abolished the effects of heat exposure on NSC/NPC proliferation. Furthermore, heat exposure under differentiation conditions increased the proportion of cells positive for Tuj1 (a neuronal marker). These findings suggest that mild heat exposure increases NSC/NPC proliferation, possibly through activation of the Akt pathway, and also enhances neuronal differentiation. Direct effects of temperature on NSCs/NPCs may be one of the mechanisms involved in hypothalamic neurogenesis in heat-acclimated rats. Such heat-induced neurogenesis could also be an effective therapeutic strategy for neurodegenerative diseases. PMID:29287093

Activation of sperm EGFR by light irradiation is mediated by reactive oxygen species.

PubMed

Shahar, Shiran; Hillman, Pnina; Lubart, Rachel; Ickowicz, Debby; Breitbart, Haim

2014-01-01

To acquire fertilization competence, spermatozoa must undergo several biochemical and motility changes in the female reproductive tract, collectively called capacitation. Actin polymerization and the development of hyperactivated motility (HAM) are part of the capacitation process. In a recent study, we showed that irradiation of human sperm with visible light stimulates HAM through a mechanism involving reactive-oxygen-species (ROS), Ca(2+) influx, protein kinases A (PKA), and sarcoma protein kinase (Src). Here, we showed that this effect of light on HAM is mediated by ROS-dependent activation of the epidermal growth factor receptor (EGFR). Interestingly, ROS-mediated HAM even when the EGFR was activated by EGF, the physiological ligand of EGFR. Light irradiation stimulated ROS-dependent actin polymerization, and this effect was abrogated by PBP10, a peptide which activates the actin-severing protein, gelsolin, and causes actin-depolymerization in human sperm. Light-stimulated tyrosine phosphorylation of Src-dependent gelsolin, resulting in enhanced HAM. Thus, light irradiation stimulates HAM through a mechanism involving Src-mediated actin polymerization. Light-stimulated HAM and in vitro-fertilization (IVF) rate in mouse sperm, and these effects were mediated by ROS and EGFR. In conclusion, we show here that irradiation of sperm with visible light, enhances their fertilization capacity via a mechanism requiring ROS, EGFR and HAM. © 2014 The American Society of Photobiology.

Mitochondrial Redox Signaling and Tumor Progression.

PubMed

Chen, Yuxin; Zhang, Haiqing; Zhou, Huanjiao Jenny; Ji, Weidong; Min, Wang

2016-03-25

Cancer cell can reprogram their energy production by switching mitochondrial oxidative phosphorylation to glycolysis. However, mitochondria play multiple roles in cancer cells, including redox regulation, reactive oxygen species (ROS) generation, and apoptotic signaling. Moreover, these mitochondrial roles are integrated via multiple interconnected metabolic and redox sensitive pathways. Interestingly, mitochondrial redox proteins biphasically regulate tumor progression depending on cellular ROS levels. Low level of ROS functions as signaling messengers promoting cancer cell proliferation and cancer invasion. However, anti-cancer drug-initiated stress signaling could induce excessive ROS, which is detrimental to cancer cells. Mitochondrial redox proteins could scavenger basal ROS and function as "tumor suppressors" or prevent excessive ROS to act as "tumor promoter". Paradoxically, excessive ROS often also induce DNA mutations and/or promotes tumor metastasis at various stages of cancer progression. Targeting redox-sensitive pathways and transcriptional factors in the appropriate context offers great promise for cancer prevention and therapy. However, the therapeutics should be cancer-type and stage-dependent.

Tocotrienol Affects Oxidative Stress, Cholesterol Homeostasis and the Amyloidogenic Pathway in Neuroblastoma Cells: Consequences for Alzheimer’s Disease

PubMed Central

Grimm, Marcus O. W.; Regner, Liesa; Mett, Janine; Stahlmann, Christoph P.; Schorr, Pascal; Nelke, Christopher; Streidenberger, Olga; Stoetzel, Hannah; Winkler, Jakob; Zaidan, Shatha R.; Thiel, Andrea; Endres, Kristina; Grimm, Heike S.; Volmer, Dietrich A.; Hartmann, Tobias

2016-01-01

One of the characteristics of Alzheimer´s disease (AD) is an increased amyloid load and an enhanced level of reactive oxidative species (ROS). Vitamin E has known beneficial neuroprotective effects, and previously, some studies suggested that vitamin E is associated with a reduced risk of AD due to its antioxidative properties. However, epidemiological studies and nutritional approaches of vitamin E treatment are controversial. Here, we investigate the effect of α-tocotrienol, which belongs to the group of vitamin E, on AD-relevant processes in neuronal cell lines. In line with the literature, α-tocotrienol reduced the ROS level in SH-SY5Y cells. In the presence of tocotrienols, cholesterol and cholesterol esters, which have been shown to be risk factors in AD, were decreased. Besides the unambiguous positive effects of tocotrienol, amyloid-β (Aβ) levels were increased accompanied by an increase in the activity of enzymes responsible for Aβ production. Proteins and gene expression of the secretases and their components remained unchanged, whereas tocotrienol accelerates enzyme activity in cell-free assays. Besides enhanced Aβ production, tocotrienols inhibited Aβ degradation in neuro 2a (N2a)-cells. Our results might help to understand the controversial findings of vitamin E studies and demonstrate that besides the known positive neuroprotective properties, tocotrienols also have negative characteristics with respect to AD. PMID:27801864

Tocotrienol Affects Oxidative Stress, Cholesterol Homeostasis and the Amyloidogenic Pathway in Neuroblastoma Cells: Consequences for Alzheimer's Disease.

PubMed

Grimm, Marcus O W; Regner, Liesa; Mett, Janine; Stahlmann, Christoph P; Schorr, Pascal; Nelke, Christopher; Streidenberger, Olga; Stoetzel, Hannah; Winkler, Jakob; Zaidan, Shatha R; Thiel, Andrea; Endres, Kristina; Grimm, Heike S; Volmer, Dietrich A; Hartmann, Tobias

2016-10-29

One of the characteristics of Alzheimer´s disease (AD) is an increased amyloid load and an enhanced level of reactive oxidative species (ROS). Vitamin E has known beneficial neuroprotective effects, and previously, some studies suggested that vitamin E is associated with a reduced risk of AD due to its antioxidative properties. However, epidemiological studies and nutritional approaches of vitamin E treatment are controversial. Here, we investigate the effect of α-tocotrienol, which belongs to the group of vitamin E, on AD-relevant processes in neuronal cell lines. In line with the literature, α-tocotrienol reduced the ROS level in SH-SY5Y cells. In the presence of tocotrienols, cholesterol and cholesterol esters, which have been shown to be risk factors in AD, were decreased. Besides the unambiguous positive effects of tocotrienol, amyloid-β (Aβ) levels were increased accompanied by an increase in the activity of enzymes responsible for Aβ production. Proteins and gene expression of the secretases and their components remained unchanged, whereas tocotrienol accelerates enzyme activity in cell-free assays. Besides enhanced Aβ production, tocotrienols inhibited Aβ degradation in neuro 2a (N2a)-cells. Our results might help to understand the controversial findings of vitamin E studies and demonstrate that besides the known positive neuroprotective properties, tocotrienols also have negative characteristics with respect to AD.

Chemical screening identifies ROCK as a target for recovering mitochondrial function in Hutchinson-Gilford progeria syndrome.

PubMed

Kang, Hyun Tae; Park, Joon Tae; Choi, Kobong; Choi, Hyo Jei Claudia; Jung, Chul Won; Kim, Gyu Ree; Lee, Young-Sam; Park, Sang Chul

2017-06-01

Hutchinson-Gilford progeria syndrome (HGPS) constitutes a genetic disease wherein an aging phenotype manifests in childhood. Recent studies indicate that reactive oxygen species (ROS) play important roles in HGPS phenotype progression. Thus, pharmacological reduction in ROS levels has been proposed as a potentially effective treatment for patient with this disorder. In this study, we performed high-throughput screening to find compounds that could reduce ROS levels in HGPS fibroblasts and identified rho-associated protein kinase (ROCK) inhibitor (Y-27632) as an effective agent. To elucidate the underlying mechanism of ROCK in regulating ROS levels, we performed a yeast two-hybrid screen and discovered that ROCK1 interacts with Rac1b. ROCK activation phosphorylated Rac1b at Ser71 and increased ROS levels by facilitating the interaction between Rac1b and cytochrome c. Conversely, ROCK inactivation with Y-27632 abolished their interaction, concomitant with ROS reduction. Additionally, ROCK activation resulted in mitochondrial dysfunction, whereas ROCK inactivation with Y-27632 induced the recovery of mitochondrial function. Furthermore, a reduction in the frequency of abnormal nuclear morphology and DNA double-strand breaks was observed along with decreased ROS levels. Thus, our study reveals a novel mechanism through which alleviation of the HGPS phenotype is mediated by the recovery of mitochondrial function upon ROCK inactivation. © 2017 The Authors. Aging Cell published by the Anatomical Society and John Wiley & Sons Ltd.

Visualizing Oxidative Cellular Stress Induced by Nanoparticles in the Subcytotoxic Range Using Fluorescence Lifetime Imaging.

PubMed

Balke, Jens; Volz, Pierre; Neumann, Falko; Brodwolf, Robert; Wolf, Alexander; Pischon, Hannah; Radbruch, Moritz; Mundhenk, Lars; Gruber, Achim D; Ma, Nan; Alexiev, Ulrike

2018-06-01

Nanoparticles hold a great promise in biomedical science. However, due to their unique physical and chemical properties they can lead to overproduction of intracellular reactive oxygen species (ROS). As an important mechanism of nanotoxicity, there is a great need for sensitive and high-throughput adaptable single-cell ROS detection methods. Here, fluorescence lifetime imaging microscopy (FLIM) is employed for single-cell ROS detection (FLIM-ROX) providing increased sensitivity and enabling high-throughput analysis in fixed and live cells. FLIM-ROX owes its sensitivity to the discrimination of autofluorescence from the unique fluorescence lifetime of the ROS reporter dye. The effect of subcytotoxic amounts of cationic gold nanoparticles in J774A.1 cells and primary human macrophages on ROS generation is investigated. FLIM-ROX measures very low ROS levels upon gold nanoparticle exposure, which is undetectable by the conventional method. It is demonstrated that cellular morphology changes, elevated senescence, and DNA damage link the resulting low-level oxidative stress to cellular adverse effects and thus nanotoxicity. Multiphoton FLIM-ROX enables the quantification of spatial ROS distribution in vivo, which is shown for skin tissue as a target for nanoparticle exposure. Thus, this innovative method allows identifying of low-level ROS in vitro and in vivo and, subsequently, promotes understanding of ROS-associated nanotoxicity. © 2018 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Expression and rearrangement of the ROS1 gene in human glioblastoma cells

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

Birchmeier, C.; Sharma, S.; Wigler, M.

1987-12-01

The human ROS1 gene, which possibly encodes a growth factor receptor, was found to be expressed in human tumor cell lines. In a survey of 45 different human cell lines, the authors found ROS1 to be expressed in glioblastoma-derived cell lines at high levels and not to be expressed at all, or expressed at very low levels, in the remaining cell lines. The ROS1 gene was present in normal copy numbers in all cell lines that expressed the gene. However, in one particular glioblastoma line, they detected a potentially activating mutation at the ROS1 locus.

Magnetic nanoparticles: reactive oxygen species generation and potential therapeutic applications

NASA Astrophysics Data System (ADS)

Mai, Trang; Hilt, J. Zach

2017-07-01

Magnetic nanoparticles have been demonstrated to produce reactive oxygen species (ROS), which play a major role in various cellular pathways, via Fenton and Haber-Weiss reaction. ROS act as a double-edged sword inside the body. At normal conditions, the generation of ROS is in balance with their elimination by scavenger systems, and they can promote cell proliferation as well as differentiation. However, at an increased level, they can cause damages to protein, lead to cellular apoptosis, and contribute to many diseases including cancer. Many recent studies proposed a variety of strategies to either suppress toxicity of ROS generation or exploit the elevated ROS levels for cancer therapy.

The role of mitochondrial reactive oxygen species in pH regulation in articular chondrocytes.

PubMed

Milner, P I; Wilkins, R J; Gibson, J S

2007-07-01

To examine the effect of O(2) and the role, and source, of reactive oxygen species (ROS) on pH regulation in articular chondrocytes. Cartilage from equine metacarpo/tarsophalangeal joints was digested (collagenase) to isolate chondrocytes and loaded with 2',7'-bis-2-(carboxyethyl)-5(6)-carboxylfluorescein, a pH-sensitive fluorophore. O(2) tension was maintained using Eschweiler tonometers and a Wosthoff gas mixer. Cells were exposed to agents which alter ROS levels, mitochondrial inhibitors and/or inhibitors of protein phosphorylation. ROS levels were determined by dichlorofluorescein and mitochondrial membrane potential measured using JC-1. pH homeostasis was dependent on ROS. Na(+)/H(+) exchanger (NHE) activity was inhibited at low O(2) tension (acid efflux reducing from 2.30+/-0.05 to 1.27+/-0.11mMmin(-1) at 1%). NHE activity correlated with ROS levels (r(2)=0.65). ROS levels were increased by antimycin A (with levels at 1% O(2) tension increasing from 59+/-9% of the value at 20% to 87+/-7%), but reduced by rotenone, myxothiazol and diphenyleneiodonium. Hypoxia induced depolarisation of the mitochondrial membrane potential (with JC-1 red-green fluorescence ratio at 1% O(2) tension decreasing to 40+/-10% of the value at 20%). The response to changes in O(2) and to antimycin A was inhibited by staurosporine, wortmanin and calyculin A. The fall in ROS levels in hypoxia reduces the ability of articular chondrocytes to regulate pH, inhibiting NHE activity via changes in protein phosphorylation. The site of ROS generation is likely to be mitochondrial electron transport chain complex III. These effects are important to understanding normal chondrocyte function and response to altered O(2) tension.

Deactivation of cisplatin-resistant human lung/ovary cancer cells with pyropheophorbide-α methyl ester-photodynamic therapy.

PubMed

Qian, Guanhua; Wang, Li; Zheng, Xueling; Yu, Tinghe

2017-12-02

The aim of this study was to determine whether photodynamic therapy (PDT) alone or combined with cisplatin (DDP), can deactivate cisplatin-resistant cancer cells. Human cancer cell lines A549 and SKOV3, and chemoresistant sublines A549/DDP and SKOV3/DDP, were subjected to PDT, DDP, or PDT combined with DDP. Cell viability and apoptosis were analyzed, and then intracellular reactive oxygen species (ROS) and proteins related to apoptosis were determined. PDT caused cell death, and PDT combined with DDP led to the highest percentage of dead cells in 4 cell lines; similar results were detected in ROS; a quantification evaluation manifested that the combined effect was addition. DDP increased the percentage of apoptotic cells, and the ROS level in A549 and SKOV3 cells, which was not observed in A549/DDP and SKOV3/DDP cells. Western blot revealed an increase of caspase 3 and Bax, and a decrease of Bcl-2, demonstrating the occurrence of apoptosis. The data suggest that PDT can efficiently deactivate resistant cells and enhance the action of DDP against resistant cancer cells.

Nuclear-localized AtHSPR links abscisic acid-dependent salt tolerance and antioxidant defense in Arabidopsis.

PubMed

Yang, Tao; Zhang, Liang; Hao, Hongyan; Zhang, Peng; Zhu, Haowei; Cheng, Wei; Wang, Yongli; Wang, Xinyu; Wang, Chongying

2015-12-01

Salt stress from soil or irrigation water limits plant growth. A T-DNA insertion mutant in C24, named athspr (Arabidopsis thaliana heat shock protein-related), showed several phenotypes, including reduced organ size and enhanced sensitivity to environmental cues. The athspr mutant is severely impaired under salinity levels at which wild-type (WT) plants grow normally. AtHSPR encodes a nuclear-localized protein with ATPase activity, and its expression was enhanced by high salinity and abscisic acid (ABA). Overexpression (OE) of AtHSPR significantly enhanced tolerance to salt stress by increasing the activities of the antioxidant system and by maintaining K(+) /Na(+) homeostasis. Quantitative RT-PCR analyses showed that OE of AtHSPR increased the expression of ABA/stress-responsive, salt overly sensitive (SOS)-related and antioxidant-related genes. In addition, ABA content was reduced in athspr plants with or without salt stress, and exogenous ABA restored WT-like salt tolerance to athspr plants. athspr exhibited increased leaf stomatal density and stomatal index, slower ABA-induced stomatal closure and reduced drought tolerance relative to the WT. AtHSPR OE enhanced drought tolerance by reducing leaf water loss and stomatal aperture. Transcript profiling in athspr showed a differential salt-stress response for genes involved in accumulation of reactive oxygen species (ROS), ABA signaling, cell death, stress response and photosynthesis. Taken together, our results suggested that AtHSPR is involved in salt tolerance in Arabidopsis through modulation of ROS levels, ABA-dependent stomatal closure, photosynthesis and K(+) /Na(+) homeostasis. © 2015 The Authors The Plant Journal © 2015 John Wiley & Sons Ltd.

Enhanced salt-induced antioxidative responses involve a contribution of polyamine biosynthesis in grapevine plants.

PubMed

Ikbal, Fatima Ezzohra; Hernández, José Antonio; Barba-Espín, Gregorio; Koussa, Tayeb; Aziz, Aziz; Faize, Mohamed; Diaz-Vivancos, Pedro

2014-06-15

The possible involvement of polyamines in the salt stress adaptation was investigated in grapevine (Vitis vinifera L.) plantlets focusing on photosynthesis and oxidative metabolism. Salt stress resulted in the deterioration of plant growth and photosynthesis, and treatment of plantlets with methylglyoxal-bis(guanylhydrazone) (MGBG), a S-adenosylmethionine decarboxylase (SAMDC) inhibitor, enhanced the salt stress effect. A decrease in PSII quantum yield (Fv/Fm), effective PSII quantum yield (Y(II)) and coefficient of photochemical quenching (qP) as well as increases in non-photochemical quenching (NPQ) and its coefficient (qN) was observed by these treatments. Salt and/or MGBG treatments also triggered an increase in lipid peroxidation and reactive oxygen species (ROS) accumulation as well as an increase of superoxide dismutase (SOD) and peroxidase (POX) activities, but not ascorbate peroxidase (APX) activity. Salt stress also resulted in an accumulation of oxidized ascorbate (DHA) and a decrease in reduced glutathione. MGBG alone or in combination with salt stress increased monodehydroascorbate reductase (MDHAR), SOD and POX activities and surprisingly no accumulation of DHA was noticed following treatment with MGBG. These salt-induced responses correlated with the maintaining of high level of free and conjugated spermidine and spermine, whereas a reduction of agmatine and putrescine levels was observed, which seemed to be amplified by the MGBG treatment. These results suggest that maintaining polyamine biosynthesis through the enhanced SAMDC activity in grapevine leaf tissues under salt stress conditions could contribute to the enhanced ROS scavenging activity and a protection of photosynthetic apparatus from oxidative damages. Copyright © 2014 Elsevier GmbH. All rights reserved.

[Effects of sika pilose antler type collagen on ROS1728 cell and its molecular mechanism].

PubMed

Wang, Yan-Shuang; Luo, Su; Zhang, Da-Fang; Qu, Xiao-Bo; Li, Feng

2016-09-01

In this paper, effect and molecular mechanism of sika pilose antler type I collagen(SPC-I) of ROS1728 cell were explored. For the SPC-I provides the theory basis for the treatment of osteoporosis. The adherent method was used to cultivate rat osteosarcoma osteogenesis sample cell line ROS1728. The effect of SPC-I on ROS1728 cells proliferation was tested by CCK-8 method. Runx2, osernix, ALP, Coll-I, OC osteogenesis related genes expression was tested by RT-PCR, and Runx2 protein expression was tested by Western-bolt. Results showed that 5 g•L ⁻¹ SPC-I could inhibit ROS1728 cell proliferation, and significantly promote the expression of ROS1728 cell specific transcription factor Runx2 and osterix mRNA, Runx2 protein and marker gene ALP, Coll-I, OC mRNA expression(P<0.01). 2.5 g•L ⁻¹ and 10 g•L ⁻¹ SPC-I could significantly inhibit the ROS1728 cell proliferation(P<0.01), and inhibit the expression of related genes. In conclusion, 5 g•L ⁻¹ SPC-I could inhibit ROS1728 cell proliferation, obviously enhance ROS1728 cell function, promote ROS1728 cell differentiation, maturation. Copyright© by the Chinese Pharmaceutical Association.

Cell Proliferation, Reactive Oxygen and Cellular Glutathione

PubMed Central

Day, Regina M.; Suzuki, Yuichiro J.

2005-01-01

A variety of cellular activities, including metabolism, growth, and death, are regulated and modulated by the redox status of the environment. A biphasic effect has been demonstrated on cellular proliferation with reactive oxygen species (ROS)—especially hydrogen peroxide and superoxide—in which low levels (usually submicromolar concentrations) induce growth but higher concentrations (usually >10–30 micromolar) induce apoptosis or necrosis. This phenomenon has been demonstrated for primary, immortalized and transformed cell types. However, the mechanism of the proliferative response to low levels of ROS is not well understood. Much of the work examining the signal transduction by ROS, including H2O2, has been performed using doses in the lethal range. Although use of higher ROS doses have allowed the identification of important signal transduction pathways, these pathways may be activated by cells only in association with ROS-induced apoptosis and necrosis, and may not utilize the same pathways activated by lower doses of ROS associated with increased cell growth. Recent data has shown that low levels of exogenous H2O2 up-regulate intracellular glutathione and activate the DNA binding activity toward antioxidant response element. The modulation of the cellular redox environment, through the regulation of cellular glutathione levels, may be a part of the hormetic effect shown by ROS on cell growth. PMID:18648617

Iron overload promotes erythroid apoptosis through regulating HIF-1a/ROS signaling pathway in patients with myelodysplastic syndrome.

PubMed

Zheng, Qing-Qing; Zhao, You-Shan; Guo, Juan; Zhao, Si-da; Song, Lu-Xi; Fei, Cheng-Ming; Zhang, Zheng; Li, Xiao; Chang, Chun-Kang

2017-07-01

Erythroid apoptosis increases significantly in myelodysplastic syndrome (MDS) patients with iron overload, but the underlying mechanism is not fully clear. In this study, we aim to explore the effect of HIF-1a/ROS on erythroid apoptosis in MDS patients with iron overload. We found that iron overload injured cellular functions through up-regulating ROS levels in MDS/AML cells, including inhibited cell viability, increased cell apoptosis and blocked cell cycle at G0/G1 phase. Interestingly, overexpression of hypoxia inducible factor-1a (HIF-1a), which was under-expressed in iron overload models, reduced ROS levels and attenuated cell damage caused by iron overload in MDS/AML cells. And gene knockdown of HIF-1a got the similar results as iron overload in MDS/AML cells. Furthermore, iron overload caused high erythroid apoptosis was closely related with ROS in MDS patients. Importantly, the HIF-1a protein levels of erythrocytes elevated obviously after incubation with desferrioxamine (DFO) from MDS patients with iron overload, accompanied by ROS levels inhibited and erythroid apoptosis reduced. Taken together, our findings determine that the HIF-1a/ROS signaling pathway plays a key role in promoting erythroid apoptosis in MDS patients with iron overload. Copyright © 2017 Elsevier Ltd. All rights reserved.

Camel whey protein protects lymphocytes from apoptosis via the PI3K/AKT, NF-κB, ATF-3 and HSP-70 signaling pathways in heat-stressed male mice.

PubMed

Badr, Gamal; Ramadan, Nancy K; Abdel-Tawab, Hanem S; Ahmed, Samia F; Mahmoud, Mohamed H

2017-11-22

Heat stress (HS) is an environmental factor that depresses the immune systems mediating dysfunctional immune cells. Camel whey protein (CWP) can scavenge free radicals and enhance immunity. The present study investigated the impact of dietary supplementation with CWP on immune dysfunction induced by exposure to HS. Male mice (n = 45) were divided into three groups: control group; HS group; and HS mice that were orally administered CWP (HS+CWP group). The HS group exhibited elevated levels of reactive oxygen species (ROS) and pro-inflammatory cytokines (IL-1β, IL-6, TNF-α) as well as a significant reduction in the IL-2 and IL-4 levels. Exposure to HS resulted in impaired AKT and IκB-α phosphorylation; increased ATF-3 and HSP70 expression; and aberrant distribution of CD3+ T cells and CD20+ B cells in the thymus and spleen. Interestingly, HS mice treated with CWP presented significantly restored levels of ROS and pro-inflammatory cytokines near the levels observed in control mice. Furthermore, supplementation of HS mice with CWP enhanced the phosphorylation of AKT and IκB-α; attenuated the expression of ATF-3, HSP70 and HSP90; and improved T and B cell distributions in the thymus and spleen. Our findings reveal a potential immunomodulatory effect of CWP in attenuating immune dysfunction induced by exposure to thermal stress.

ROS-activated Ca/calmodulin kinase IIδ is required for late INa augmentation leading to cellular Na and Ca overload

PubMed Central

Wagner, Stefan; Ruff, Hanna M.; Weber, Sarah L.; Bellmann, Sarah; Sowa, Thomas; Schulte, Timo; Grandi, Eleonora; Bers, Donald M.; Backs, Johannes; Belardinelli, Luiz; Maier, Lars S.

2011-01-01

Rationale In heart failure (HF), CaMKII expression and reactive oxygen species (ROS) are increased. Both ROS and CaMKII can increase late INa leading to intracellular Na accumulation and arrhythmias. It has been shown that ROS can activate CaMKII via oxidation. Objective We tested whether CaMKIIδ is required for ROS-dependent late INa regulation and if ROS-induced Ca released from the sarcoplasmic reticulum (SR) is involved. Methods and Results 40 µmol/L H2O2 significantly increased CaMKII oxidation and autophosphorylation in permeabilized rabbit cardiomyocytes. Without free [Ca]i (5 mmol/L BAPTA/1 mmol/L Br2-BAPTA) or after SR depletion (caffeine 10 mmol/L, thapsigargin 5 µmol/L) the H2O2-dependent CaMKII oxidation and autophosphorylation was abolished. H2O2 significantly increased SR Ca spark frequency (confocal microscopy) but reduced SR Ca load. In wildtype (WT) mouse myocytes, H2O2 increased late INa (whole cell patch-clamp). This increase was abolished in CaMKIIδ−/− myocytes. H2O2-induced [Na]i and [Ca]i accumulation (SBFI and Indo-1 epifluorescence) was significantly slowed in CaMKIIδ−/− myocytes (vs. WT). CaMKIIδ−/− myocytes developed significantly less H2O2-induced arrhythmias, and were more resistant to hypercontracture. Opposite results (increased late INa, [Na]i and [Ca]i accumulation) were obtained by overexpression of CaMKIIδ in rabbit myocytes (adenoviral gene transfer) reversible with CaMKII inhibition (10 µmol/L KN93 or 0.1 µmol/L AIP). Conclusion Free [Ca]i and a functional SR are required for ROS activation of CaMKII. ROS-activated CaMKIIδ enhances late INa, which may lead to cellular Na and Ca overload. This may be of relevance in HF, where enhanced ROS production meets increased CaMKII expression. PMID:21252154

Do antioxidant supplements interfere with skeletal muscle adaptation to exercise training?

PubMed Central

Ristow, Michael

2016-01-01

Abstract A popular belief is that reactive oxygen species (ROS) and reactive nitrogen species (RNS) produced during exercise by the mitochondria and other subcellular compartments ubiquitously cause skeletal muscle damage, fatigue and impair recovery. However, the importance of ROS and RNS as signals in the cellular adaptation process to stress is now evident. In an effort to combat the perceived deleterious effects of ROS and RNS it has become common practice for active individuals to ingest supplements with antioxidant properties, but interfering with ROS/RNS signalling in skeletal muscle during acute exercise may blunt favourable adaptation. There is building evidence that antioxidant supplementation can attenuate endurance training‐induced and ROS/RNS‐mediated enhancements in antioxidant capacity, mitochondrial biogenesis, cellular defence mechanisms and insulin sensitivity. However, this is not a universal finding, potentially indicating that there is redundancy in the mechanisms controlling skeletal muscle adaptation to exercise, meaning that in some circumstances the negative impact of antioxidants on acute exercise response can be overcome by training. Antioxidant supplementation has been more consistently reported to have deleterious effects on the response to overload stress and high‐intensity training, suggesting that remodelling of skeletal muscle following resistance and high‐intensity exercise is more dependent on ROS/RNS signalling. Importantly there is no convincing evidence to suggest that antioxidant supplementation enhances exercise‐training adaptions. Overall, ROS/RNS are likely to exhibit a non‐linear (hormetic) pattern on exercise adaptations, where physiological doses are beneficial and high exposure (which would seldom be achieved during normal exercise training) may be detrimental. PMID:26638792

Sex as a response to oxidative stress: a twofold increase in cellular reactive oxygen species activates sex genes.

PubMed

Nedelcu, Aurora M; Marcu, Oana; Michod, Richard E

2004-08-07

Organisms are constantly subjected to factors that can alter the cellular redox balance and result in the formation of a series of highly reactive molecules known as reactive oxygen species (ROS). As ROS can be damaging to biological structures, cells evolved a series of mechanisms (e.g. cell-cycle arrest, programmed cell death) to respond to high levels of ROS (i.e. oxidative stress). Recently, we presented evidence that in a facultatively sexual lineage--the multicellular green alga Volvox carteri--sex is an additional response to increased levels of stress, and probably ROS and DNA damage. Here we show that, in V. carteri, (i) sex is triggered by an approximately twofold increase in the level of cellular ROS (induced either by the natural sex-inducing stress, namely heat, or by blocking the mitochondrial electron transport chain with antimycin A), and (ii) ROS are responsible for the activation of sex genes. As most types of stress result in the overproduction of ROS, we believe that our findings will prove to extend to other facultatively sexual lineages, which could be indicative of the ancestral role of sex as an adaptive response to stress and ROS-induced DNA damage. Copyright 2004 The Royal Society

High level of chromosomal instability in circulating tumor cells of ROS1-rearranged non-small-cell lung cancer.

PubMed

Pailler, E; Auger, N; Lindsay, C R; Vielh, P; Islas-Morris-Hernandez, A; Borget, I; Ngo-Camus, M; Planchard, D; Soria, J-C; Besse, B; Farace, F

2015-07-01

Genetic aberrations affecting the c-ros oncogene 1 (ROS1) tyrosine kinase gene have been reported in a small subset of patients with non-small-cell lung cancer (NSCLC). We evaluated whether ROS1-chromosomal rearrangements could be detected in circulating tumor cells (CTCs) and examined tumor heterogeneity of CTCs and tumor biopsies in ROS1-rearranged NSCLC patients. Using isolation by size of epithelial tumor cells (ISET) filtration and filter-adapted-fluorescence in situ hybridization (FA-FISH), ROS1 rearrangement was examined in CTCs from four ROS1-rearranged patients treated with the ROS1-inhibitor, crizotinib, and four ROS1-negative patients. ROS1-gene alterations observed in CTCs at baseline from ROS1-rearranged patients were compared with those present in tumor biopsies and in CTCs during crizotinib treatment. Numerical chromosomal instability (CIN) of CTCs was assessed by DNA content quantification and chromosome enumeration. ROS1 rearrangement was detected in the CTCs of all four patients with ROS1 rearrangement previously confirmed by tumor biopsy. In ROS1-rearranged patients, median number of ROS1-rearranged CTCs at baseline was 34.5 per 3 ml blood (range, 24-55). In ROS1-negative patients, median background hybridization of ROS1-rearranged CTCs was 7.5 per 3 ml blood (range, 7-11). Tumor heterogeneity, assessed by ROS1 copy number, was significantly higher in baseline CTCs compared with paired tumor biopsies in the three patients experiencing PR or SD (P < 0.0001). Copy number in ROS1-rearranged CTCs increased significantly in two patients who progressed during crizotinib treatment (P < 0.02). CTCs from ROS1-rearranged patients had a high DNA content and gain of chromosomes, indicating high levels of aneuploidy and numerical CIN. We provide the first proof-of-concept that CTCs can be used for noninvasive and sensitive detection of ROS1 rearrangement in NSCLC patients. CTCs from ROS1-rearranged patients show considerable heterogeneity of ROS1-gene abnormalities and elevated numerical CIN, a potential mechanism to escape ROS1-inhibitor therapy in ROS1-rearranged NSCLC tumors. © The Author 2015. Published by Oxford University Press on behalf of the European Society for Medical Oncology.

Intraplatelet reactive oxygen species (ROS) correlate with the shedding of adhesive receptors, microvesiculation and platelet adhesion to collagen during storage: Does endogenous ROS generation downregulate platelet adhesive function?

PubMed

Ghasemzadeh, Mehran; Hosseini, Ehteramolsadat; Roudsari, Zahra Oushyani; Zadkhak, Parvin

2018-03-01

Platelets storage lesion is mainly orchestrated by platelet activating signals during storage. Reactive oxygen species (ROS) are being considered as important signaling molecules modulating platelet function while their production has also been shown to be augmented by platelet activation. This study investigated to what extent endogenous ROS generation during platelet storage could be correlated with platelet receptor shedding, microvesiculation and adhesive function. 10 PRP-platelet concentrates were subjected to flow cytometry analysis to examine the generation of intraplatelet ROS on days 1, 5 and 7 after storage. In 5 day-stored platelets considering 40% of ROS generation as a cutoff point, samples were divided into two groups of those with higher or lower levels of ROS. The expression of adhesion receptors (GPVI, GPIbα), the amount of microparticles and phosphatidylserine exposure in each group were then examined by flow cytometry. Platelet receptor shedding and adhesion to collagen matrix were respectively measured by western blotting and microscopic assays. Our data showed lowered expression of GPIbα (p < 0.05) and GPVI in samples with ROS > 40% than those with ROS ≤ 40%, whereas receptors shedding and microvesiculation were (p < 0.05) elevated in platelets with higher levels of ROS. Functionally, we observed significantly (p < 0.05) lower levels of platelet adhesion to collagen matrix in samples with ROS generation more than 40%. Taken together, we showed correlations between intraplatelet ROS generation and either platelet receptors or microparticle shedding as well as platelet adhesive capacity to collagen. These findings suggest that augmented ROS generation during storage might be relevant to down-regulation of platelet adhesive function. Copyright © 2018 Elsevier Ltd. All rights reserved.

Vitamin E, γ-tocotrienol, Protects Against Buthionine Sulfoximine-Induced Cell Death by Scavenging Free Radicals in SH-SY5Y Neuroblastoma Cells.

PubMed

Tan, Jen-Kit; Then, Sue-Mian; Mazlan, Musalmah; Jamal, Rahman; Ngah, Wan Zurinah Wan

2016-01-01

The induction of reactive oxygen species (ROS) to selectively kill cancer cells is an important feature of radiotherapy and various chemotherapies. Depletion of glutathione can induce apoptosis in cancer cells or sensitize them to anticancer treatments intended to modulate ROS levels. In contrast, antioxidants protect cancer cells from oxidative stress-induced cell death by scavenging ROS. The role of exogenous antioxidants in cancer cells under oxidative insults remains controversial and unclear. This study aimed to identify protective pathways modulated by γ-tocotrienol (γT3), an isomer of vitamin E, in human neuroblastoma SH-SY5Y cells under oxidative stress. Using buthionine sulfoximine (BSO) as an inhibitor of glutathione synthesis, we found that BSO treatment reduced the viability of SH-SY5Y cells. BSO induced cell death by increasing apoptosis, decreased the level of reduced glutathione (GSH), and increased ROS levels in SH-SY5Y cells. Addition of γT3 increased the viability of BSO-treated cells, suppressed apoptosis, and decreased the ROS level induced by BSO, while the GSH level was unaffected. These results suggest that decreasing GSH levels by BSO increased ROS levels, leading to apoptosis in SH-SY5Y cells. γT3 attenuated the BSO-induced cell death by scavenging free radicals.

Trehalose improves rabbit sperm quality during cryopreservation.

PubMed

Zhu, Zhendong; Fan, Xiaoteng; Pan, Yang; Lu, Yinghua; Zeng, Wenxian

2017-04-01

High levels of reactive oxygen species are associated with spermatozoa cryopreservation, which bring damage to functional spermatozoa. The aim of the present study was to investigate whether and how the freezing extenders supplemented with trehalose was beneficial for the survival of rabbit spermatozoa. semen was diluted with Tris-citrate-glucose extender addition of different concentrations of trehalose. Addition of 100 mM trehaose significantly improved post-thaw rabbit sperm parameters, such as motility, acrosome integriy, membrane integrity and mitochondrial membrane potential. Moreover, when freezing extenders supplemented with trehalose, activities of catalase (CAT), superoxide dismutase (SOD) and total antioxidant capacity (T-AOC) of post-thaw spermatozoa were enhanced, meanwhile, reactive oxygen species (ROS) level and Malondialdehyde (MDA) content were decreased. The results suggest that freezing extenders supplemented with 100 mM trehalose resulted in less ROS level and MDA content, higher motility and mitochondrial membrane potential as well as the integrity of acrosome and plasma membrane. Supplementation of trehalose with freezing extenders is beneficial to the rabbit breeding industry. Copyright © 2017 Elsevier Inc. All rights reserved.

Up-regulation of antioxidant enzymes and coenzyme Q(10) in a human oral cancer cell line with acquired bleomycin resistance.

PubMed

Yen, Hsiu-Chuan; Li, Sin-Hua; Majima, Hideyuki J; Huang, Yu-Hsiang; Chen, Chiu-Ping; Liu, Chia-Chi; Tu, Ya-Chi; Chen, Chih-Wei

2011-06-01

Bleomycin (BLM) is an anti-cancer drug that can induce formation of reactive oxygen species (ROS). To investigate the association between up-regulation of antioxidant enzymes and coenzyme Q(10) (CoQ(10)) in acquired BLM resistance, one BLM-resistant clone, SBLM24 clone, was selected from a human oral cancer cell line, SCC61 clone. The BLM resistance of SBLM24 clone relative to a sub-clone of SCC61b cells was confirmed by analysis of clonogenic ability and cell cycle arrest. CoQ(10) levels and levels of Mn superoxide dismutase, glutathione peroxidase 1, catalase and thioredoxin reductase 1 were augmented in SBLM24 clone although there was also a mild increase in the expression of BLM hydrolase. Suppression of CoQ(10) levels by 4-aminobenzoate sensitized BLM-induced cytotoxicity. The results of suppression on enhanced ROS production by BLM and the cross-resistance to hydrogen peroxide in SBLM24 clone further demonstrated the development of adaptation to oxidative stress during the formation of acquired BLM resistance.

Diisopropylamine dichloroacetate enhances radiosensitization in esophageal squamous cell carcinoma by increasing mitochondria-derived reactive oxygen species levels

PubMed Central

Yu, Decai; Mao, Qixing; Xia, Wenjie; Shi, Run; Wang, Jie; Xu, Lin

2016-01-01

Radiotherapy is generally applied in the treatment of esophageal squamous cell carcinoma (ESCC). However, the radioresistance of ESCC still remains an obstacle for the curative effect of this treatment. We hypothesized that diisopropylamine dichloroacetate (DADA), an inhibitor of pyruvate dehydrogenase kinase (PDK), might enhance radiosensitizationin resistant ESCC. The clonogenic survival assay revealed that DADA sensitized ESCC cells to radiotherapy in vitro; furthermore, the combination of DADA and radiotherapy increased the expression of γ-H2AX, which is a hallmark of DNA double-strand breaks. Arrest at G2/M phase as well as the induction of apoptosis of ESCC cells were also observed in the cells treated with the combination of DADA and radiotherapy. Notably, xenograft tumor growth was significantly suppressed in vivo by combined radiotherapy and DADA administration. It has been proven that glycolysis is highly correlated with radioresistance, which could be reversed by the shift from glycolysis to mitochondrial oxidation. In our present study, we found that DADA could modulate oxidative phosphorylation as well as increase the intracellular levels of reactive oxygen species (ROS). Collectively, we concluded that DADA-induced intracellular ROS accumulation was identified as the key factor of radiotherapy sensitization of ESCC. PMID:27626688

Enhanced oxidative stress and aberrant mitochondrial biogenesis in human neuroblastoma SH-SY5Y cells during methamphetamine induced apoptosis

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

Wu, C.-W.; Ping, Y.-H.; Department of Education and Research, Taipei City Hospital, Taipei, Taiwan

2007-05-01

Methamphetamine (METH) is an abused drug that may cause psychiatric and neurotoxic damage, including degeneration of monoaminergic terminals and apoptosis of non-monoaminergic cells in Brain. The cellular and molecular mechanisms underlying these METH-induced neurotoxic effects remain to be clarified. In this study, we performed a time course assessment to investigate the effects of METH on intracellular oxidative stress and mitochondrial alterations in a human dopaminergic neuroblastoma SH-SY5Y cell line. We characterized that METH induces a temporal sequence of several cellular events including, firstly, a decrease in mitochondrial membrane potential within 1 h of the METH treatment, secondly, an extensive declinemore » in mitochondrial membrane potential and increase in the level of reactive oxygen species (ROS) after 8 h of the treatment, thirdly, an increase in mitochondrial mass after the drug treatment for 24 h, and finally, a decrease in mtDNA copy number and mitochondrial proteins per mitochondrion as well as the occurrence of apoptosis after 48 h of the treatment. Importantly, vitamin E attenuated the METH-induced increases in intracellular ROS level and mitochondrial mass, and prevented METH-induced cell death. Our observations suggest that enhanced oxidative stress and aberrant mitochondrial biogenesis may play critical roles in METH-induced neurotoxic effects.« less

Ketogenic diets as an adjuvant cancer therapy: History and potential mechanism

PubMed Central

Allen, Bryan G.; Bhatia, Sudershan K.; Anderson, Carryn M.; Eichenberger-Gilmore, Julie M.; Sibenaller, Zita A.; Mapuskar, Kranti A.; Schoenfeld, Joshua D.; Buatti, John M.; Spitz, Douglas R.; Fath, Melissa A.

2014-01-01

Cancer cells, relative to normal cells, demonstrate significant alterations in metabolism that are proposed to result in increased steady-state levels of mitochondrial-derived reactive oxygen species (ROS) such as O2•−and H2O2. It has also been proposed that cancer cells increase glucose and hydroperoxide metabolism to compensate for increased levels of ROS. Given this theoretical construct, it is reasonable to propose that forcing cancer cells to use mitochondrial oxidative metabolism by feeding ketogenic diets that are high in fats and low in glucose and other carbohydrates, would selectively cause metabolic oxidative stress in cancer versus normal cells. Increased metabolic oxidative stress in cancer cells would in turn be predicted to selectively sensitize cancer cells to conventional radiation and chemotherapies. This review summarizes the evidence supporting the hypothesis that ketogenic diets may be safely used as an adjuvant therapy to conventional radiation and chemotherapies and discusses the proposed mechanisms by which ketogenic diets may enhance cancer cell therapeutic responses. PMID:25460731

Superb hydroxyl radical-mediated biocidal effect induced antibacterial activity of tuned ZnO/chitosan type II heterostructure under dark

NASA Astrophysics Data System (ADS)

Podder, Soumik; Halder, Suman; Roychowdhury, Anirban; Das, Dipankar; Ghosh, Chandan Kr.

2016-10-01

Reactive oxygen species (ROS) is the most dominating factor for bacteria cell toxicity due to release of oxidative stress. Hydroxyl radical (·OH) is a strong oxidizing ROS that has high impact on biocidal activity. This present paper highlights ·OH influenced antibacterial activity and biocidal propensity of tuned ZnO/chitosan (ZnO/CS) nanocomposite against Pseudomonas putida (P. putida) in the absence of light for the first time. For this purpose, the CS proportion was increased by 25 % (w/w) of ZnO during the preparation of ZnO/CS nanocomposite and a systematic study of different ROS like superoxide anion (O 2 ·- ), hydrogen peroxide (H2O2) and ·OH production as well as their kinetics was carried out both under UV irradiation and in dark by UV-Vis spectroscopy using NBT dye, starch and iodine reaction and fluorescence spectroscopy using terephthalic acid. The decoration of ZnO nanoparticles (ZnO·NPs) with CS tuning was characterized by XRD and FTIR spectroscopy, revealing sustained crystallinity and surface coating of ZnO NP (size about 24 nm) by CS molecule. The hybridization of ZnO nanoparticles with CS@50 wt% (w/w) resulted superior biocidal activity (81 %) within 3 h in dark mediated by optimum production of ·OH among all ROS. Here we have proposed the enhanced production of ·OH in ZnO/CS due to generation of holes by entrapment of electrons in acceptor level formed in nanocomposite for the first time, and the acceptor levels were probed by Positron annihilation lifetime spectroscopy. The increase in non-positronium (non-Ps) formation probability (I2) in ZnO/CS nanocomposite confirmed the acceptor levels. This work also confirms surface defect-mediated ROS generation in dark, and zinc interstitials are proposed as active defect sites for generation of holes and ·OH for the first time and confirmed by steady-state room temperature photoluminescence spectroscopy. Finally, a plausible mechanism was hypothesized focusing on hole generation in ZnO NP and hole transfer from CS for the first time, and a heterostructure of type II was proposed.

Asbestos Induces Oxidative Stress and Activation of Nrf2 Signaling in Murine Macrophages: Chemopreventive Role of the Synthetic Lignan Secoisolariciresinol Diglucoside (LGM2605).

PubMed

Pietrofesa, Ralph A; Velalopoulou, Anastasia; Albelda, Steven M; Christofidou-Solomidou, Melpo

2016-03-01

The interaction of asbestos fibers with macrophages generates harmful reactive oxygen species (ROS) and subsequent oxidative cell damage that are key processes linked to malignancy. Secoisolariciresinol diglucoside (SDG) is a non-toxic, flaxseed-derived pluripotent compound that has antioxidant properties and may thus function as a chemopreventive agent for asbestos-induced mesothelioma. We thus evaluated synthetic SDG (LGM2605) in asbestos-exposed, elicited murine peritoneal macrophages as an in vitro model of tissue phagocytic response to the presence of asbestos in the pleural space. Murine peritoneal macrophages (MFs) were exposed to crocidolite asbestos fibers (20 µg/cm²) and evaluated at various times post exposure for cytotoxicity, ROS generation, malondialdehyde (MDA), and levels of 8-iso Prostaglandin F2α (8-isoP). We then evaluated the ability of LGM2605 to mitigate asbestos-induced oxidative stress by administering LGM2605 (50 µM) 4-h prior to asbestos exposure. We observed a significant (p < 0.0001), time-dependent increase in asbestos-induced cytotoxicity, ROS generation, and the release of MDA and 8-iso Prostaglandin F2α, markers of lipid peroxidation, which increased linearly over time. LGM2605 treatment significantly (p < 0.0001) reduced asbestos-induced cytotoxicity and ROS generation, while decreasing levels of MDA and 8-isoP by 71%-88% and 41%-73%, respectively. Importantly, exposure to asbestos fibers induced cell protective defenses, such as cellular Nrf2 activation and the expression of phase II antioxidant enzymes, HO-1 and Nqo1 that were further enhanced by LGM2605 treatment. LGM2605 boosted antioxidant defenses, as well as reduced asbestos-induced ROS generation and markers of oxidative stress in murine peritoneal macrophages, supporting its possible use as a chemoprevention agent in the development of asbestos-induced malignant mesothelioma.

Asbestos Induces Oxidative Stress and Activation of Nrf2 Signaling in Murine Macrophages: Chemopreventive Role of the Synthetic Lignan Secoisolariciresinol Diglucoside (LGM2605)

PubMed Central

Pietrofesa, Ralph A.; Velalopoulou, Anastasia; Albelda, Steven M.; Christofidou-Solomidou, Melpo

2016-01-01

The interaction of asbestos fibers with macrophages generates harmful reactive oxygen species (ROS) and subsequent oxidative cell damage that are key processes linked to malignancy. Secoisolariciresinol diglucoside (SDG) is a non-toxic, flaxseed-derived pluripotent compound that has antioxidant properties and may thus function as a chemopreventive agent for asbestos-induced mesothelioma. We thus evaluated synthetic SDG (LGM2605) in asbestos-exposed, elicited murine peritoneal macrophages as an in vitro model of tissue phagocytic response to the presence of asbestos in the pleural space. Murine peritoneal macrophages (MFs) were exposed to crocidolite asbestos fibers (20 µg/cm2) and evaluated at various times post exposure for cytotoxicity, ROS generation, malondialdehyde (MDA), and levels of 8-iso Prostaglandin F2α (8-isoP). We then evaluated the ability of LGM2605 to mitigate asbestos-induced oxidative stress by administering LGM2605 (50 µM) 4-h prior to asbestos exposure. We observed a significant (p < 0.0001), time-dependent increase in asbestos-induced cytotoxicity, ROS generation, and the release of MDA and 8-iso Prostaglandin F2α, markers of lipid peroxidation, which increased linearly over time. LGM2605 treatment significantly (p < 0.0001) reduced asbestos-induced cytotoxicity and ROS generation, while decreasing levels of MDA and 8-isoP by 71%–88% and 41%–73%, respectively. Importantly, exposure to asbestos fibers induced cell protective defenses, such as cellular Nrf2 activation and the expression of phase II antioxidant enzymes, HO-1 and Nqo1 that were further enhanced by LGM2605 treatment. LGM2605 boosted antioxidant defenses, as well as reduced asbestos-induced ROS generation and markers of oxidative stress in murine peritoneal macrophages, supporting its possible use as a chemoprevention agent in the development of asbestos-induced malignant mesothelioma. PMID:26938529

Confocal fluorescence assessment of bioenergy/redox status of dromedary camel (Camelus dromedarius) oocytes before and after in vitro maturation.

PubMed

Russo, Roberto; Monaco, Davide; Rubessa, Marcello; El-Bahrawy, Khalid A; El-Sayed, Ashraf; Martino, Nicola A; Beneult, Benedicte; Ciannarella, Francesca; Dell'Aquila, Maria E; Lacalandra, Giovanni M; Filioli Uranio, Manuel

2014-02-18

Reproductive biotechnologies in dromedary camel (Camelus dromedarius) are less developed than in other livestock species. The in vitro maturation (IVM) technology is a fundamental step for in vitro embryo production (IVP), and its optimization could represent a way to increase the success rate of IVP. The aim of the present study was to investigate the bioenergy/oxidative status of dromedary camel oocytes before and after IVM by confocal microscopy 3D imaging. Oocytes were retrieved by slicing ovaries collected at local slaughterhouses. Recovered oocytes were examined before and after IVM culture for nuclear chromatin configuration and bioenergy/oxidative status, expressed as mitochondria (mt) distribution and activity, intracellular Reactive Oxygen Species (ROS) levels and distribution and mt/ROS colocalization. The mean recovery rate was 6 oocytes/ovary. After IVM, 61% of oocytes resumed meiosis and 36% reached the Metaphase II stage (MII). Oocyte bioenergy/redox confocal characterization revealed changes upon meiosis progression. Immature oocytes at the germinal vesicle (GV) stage were characterised by prevailing homogeneous mt distribution in small aggregates while MI and MII oocytes showed significantly higher rates of pericortical mt distribution organized in tubular networks (P<0.05). Increased mt activity in MI (P<0.001) and MII (P<0.01) oocytes compared to GV stage oocytes was also observed. At any meiotic stage, homogeneous distribution of intracellular ROS was observed. Intracellular ROS levels also increased in MI (P<0.01) and MII (P<0.05) oocytes compared to GV stage oocytes. The mt/ROS colocalization signal increased in MI oocytes (P<0.05). This study provides indications that qualitative and quantitative indicators of bioenergy and oxidative status in dromedary camel oocytes are modified in relation with oocyte meiotic stage. These data may increase the knowledge of camel oocyte physiology, in order to enhance the efficiency of IVP procedures.

Confocal fluorescence assessment of bioenergy/redox status of dromedary camel (Camelus dromedarius) oocytes before and after in vitro maturation

PubMed Central

2014-01-01

Background Reproductive biotechnologies in dromedary camel (Camelus dromedarius) are less developed than in other livestock species. The in vitro maturation (IVM) technology is a fundamental step for in vitro embryo production (IVP), and its optimization could represent a way to increase the success rate of IVP. The aim of the present study was to investigate the bioenergy/oxidative status of dromedary camel oocytes before and after IVM by confocal microscopy 3D imaging. Methods Oocytes were retrieved by slicing ovaries collected at local slaughterhouses. Recovered oocytes were examined before and after IVM culture for nuclear chromatin configuration and bioenergy/oxidative status, expressed as mitochondria (mt) distribution and activity, intracellular Reactive Oxygen Species (ROS) levels and distribution and mt/ROS colocalization. Results The mean recovery rate was 6 oocytes/ovary. After IVM, 61% of oocytes resumed meiosis and 36% reached the Metaphase II stage (MII). Oocyte bioenergy/redox confocal characterization revealed changes upon meiosis progression. Immature oocytes at the germinal vesicle (GV) stage were characterised by prevailing homogeneous mt distribution in small aggregates while MI and MII oocytes showed significantly higher rates of pericortical mt distribution organized in tubular networks (P < 0.05). Increased mt activity in MI (P < 0.001) and MII (P < 0.01) oocytes compared to GV stage oocytes was also observed. At any meiotic stage, homogeneous distribution of intracellular ROS was observed. Intracellular ROS levels also increased in MI (P < 0.01) and MII (P < 0.05) oocytes compared to GV stage oocytes. The mt/ROS colocalization signal increased in MI oocytes (P < 0.05). Conclusions This study provides indications that qualitative and quantitative indicators of bioenergy and oxidative status in dromedary camel oocytes are modified in relation with oocyte meiotic stage. These data may increase the knowledge of camel oocyte physiology, in order to enhance the efficiency of IVP procedures. PMID:24548378

Formononetin potentiates epirubicin-induced apoptosis via ROS production in HeLa cells in vitro.

PubMed

Lo, Yu-Li; Wang, Wanjen

2013-10-05

The frequent development of multidrug resistance (MDR) hampers the efficacy of available anticancer drugs in treating cervical cancer. In this study, we aimed to use formononetin (7-hydroxy-4'-methoxyisoflavone), a potential herbal isoflavone, to intensify the chemosensitivity of human cervical cancer HeLa cells to epirubicin, an anticancer drug. The reactive oxygen species (ROS) levels were correlated with MDR modulation mechanisms, including the transporter inhibition and apoptosis induction. Our results revealed that formononetin significantly enhanced the cytotoxicity of epirubicin. Co-incubation of epirubicin with formononetin increased the ROS levels, including hydrogen peroxide and superoxide free radicals. Epirubicin alone markedly increased the mRNA expression of MDR1, MDR-associated protein (MRP) 1, and MRP2. In contrast, formononetin alone or combined treatment decreased the mRNA expression of MRP1 and MRP2. This result indicates that efflux transporter-mediated epirubicin resistance is inhibited at different degrees by the addition of formononetin. This isoflavone significantly intensified epirubicin uptake into HeLa cells. Apoptosis was induced by formononetin and/or epirubicin, as signified by nuclear DNA fragmentation, chromatin condensation, increased sub-G1 and G2/M phases. The cotreatment triggered the mitochondrial apoptotic pathway indicated by increased Bax-to-Bcl-2 expression ratio, loss of mitochondrial membrane potential, and significant activation of caspase-9 and -3. In addition, extrinsic/caspases-8 apoptotic pathway was also induced by the cotreatment. N-acetyl cysteine abrogated these events induced by formononetin, supporting the involvement of ROS in the MDR reversal mechanism. This study pioneered in demonstrating that formononetin may potentiate the cytotoxicity of epirubicin in HeLa cells through the ROS-mediated MRP inhibition and concurrent activation of the mitochondrial and death receptor pathways of apoptosis. Hence, the circumvention of pump and non-pump resistance using formononetin and epirubicin may pave the way for a powerful chemotherapeutic regimen for treating human cervical cancer. Copyright © 2013 Elsevier Ireland Ltd. All rights reserved.

Oxalate-curcumin–based probe for micro- and macroimaging of reactive oxygen species in Alzheimer’s disease

PubMed Central

Yang, Jian; Zhang, Xueli; Yang, Jing; Xu, Yungen; Grutzendler, Jaime; Shao, Yihan; Moore, Anna; Ran, Chongzhao

2017-01-01

Alzheimer’s disease (AD) is an irreversible neurodegenerative disorder that has a progression that is closely associated with oxidative stress. It has long been speculated that the reactive oxygen species (ROS) level in AD brains is much higher than that in healthy brains. However, evidence from living beings is scarce. Inspired by the “chemistry of glow stick,” we designed a near-IR fluorescence (NIRF) imaging probe, termed CRANAD-61, for sensing ROS to provide evidence at micro- and macrolevels. In CRANAD-61, an oxalate moiety was utilized to react with ROS and to consequentially produce wavelength shifting. Our in vitro data showed that CRANAD-61 was highly sensitive and rapidly responsive to various ROS. On reacting with ROS, its excitation and emission wavelengths significantly shifted to short wavelengths, and this shifting could be harnessed for dual-color two-photon imaging and transformative NIRF imaging. In this report, we showed that CRANAD-61 could be used to identify “active” amyloid beta (Aβ) plaques and cerebral amyloid angiopathy (CAA) surrounded by high ROS levels with two-photon imaging (microlevel) and to provide relative total ROS concentrations in AD brains via whole-brain NIRF imaging (macrolevel). Lastly, we showed that age-related increases in ROS levels in AD brains could be monitored with our NIRF imaging method. We believe that our imaging with CRANAD-61 could provide evidence of ROS at micro- and macrolevels and could be used for monitoring ROS changes under various AD pathological conditions and during drug treatment. PMID:29109280

Bisphenol A, bisphenol S, bisphenol F and bisphenol AF induce different oxidative stress and damage in human red blood cells (in vitro study).

PubMed

Maćczak, Aneta; Cyrkler, Monika; Bukowska, Bożena; Michałowicz, Jaromir

2017-06-01

Bisphenol A (BPA) and its analogs are widely used in the production of various everyday use products, which leads to a common exposure of humans to these substances. The effect of bisphenols on oxidative stress parameters has not been described in detail in non-nucleated cells, therefore, we have decided to evaluate the impact of BPA and its analogs, i.e. bisphenol S (BPS), bisphenol F (BPF) and bisphenol AF (BPAF) on reactive oxygen species (ROS) formation, lipid peroxidation, glutathione (GSH) level and the activities of superoxide dismutase (SOD), catalase (CAT) and glutathione peroxidase (GSH-Px) in human erythrocytes. The erythrocytes were incubated with the compounds studied in the concentrations ranging from 0.1 to 500μg/ml for 1, 4 or 24h. It has been found that bisphenols enhanced ROS (including • OH) formation, depleted GSH level, increased lipid peroxidation and changed the activities of SOD, CAT and GSH-Px. It has been noted that the strongest alterations in ROS formation, lipid peroxidation and the activity of antioxidant enzymes were induced by BPAF, which changed CAT and SOD activity even at 0.5μg/ml. It has also been shown that BPA caused the strongest changes in GSH level, while BPS, which is the main BPA substituent in the manufacture did not alter most parameters studied. Copyright © 2017 Elsevier B.V. All rights reserved.

Mitochondrial Transfer from Wharton's Jelly Mesenchymal Stem Cell to MERRF Cybrid Reduces Oxidative Stress and Improves Mitochondrial Bioenergetics

PubMed Central

Liou, Chia-Wei; Chen, Shang-Der; Wang, Pei-Wen; Chuang, Jiin-Haur; Tiao, Mao-Meng; Hsu, Te-Yao

2017-01-01

Myoclonus epilepsy associated with ragged-red fibers (MERRF) is a maternally inherited mitochondrial disease affecting neuromuscular functions. Mt.8344A>G mutation in mitochondrial DNA (mtDNA) is the most common cause of MERRF syndrome and has been linked to an increase in reactive oxygen species (ROS) level and oxidative stress, as well as impaired mitochondrial bioenergetics. Here, we tested whether WJMSC has therapeutic potential for the treatment of MERRF syndrome through the transfer of mitochondria. The MERRF cybrid cells exhibited a high mt.8344A>G mutation ratio, enhanced ROS level and oxidative damage, impaired mitochondrial bioenergetics, defected mitochondria-dependent viability, exhibited an imbalance of mitochondrial dynamics, and are susceptible to apoptotic stress. Coculture experiments revealed that mitochondria were intercellularly conducted from the WJMSC to the MERRF cybrid. Furthermore, WJMSC transferred mitochondria exclusively to cells with defective mitochondria but not to cells with normal mitochondria. MERRF cybrid following WJMSC coculture (MF+WJ) demonstrated improvement of mt.8344A>G mutation ratio, ROS level, oxidative damage, mitochondrial bioenergetics, mitochondria-dependent viability, balance of mitochondrial dynamics, and resistance against apoptotic stress. WJMSC-derived mitochondrial transfer and its therapeutic effect were noted to be blocked by F-actin depolymerizing agent cytochalasin B. Collectively, the WJMSC ability to rescue cells with defective mitochondrial function through donating healthy mitochondria may lead to new insights into the development of more efficient strategies to treat diseases related to mitochondrial dysfunction. PMID:28607632

Hesperetin Induces the Apoptosis of Gastric Cancer Cells via Activating Mitochondrial Pathway by Increasing Reactive Oxygen Species.

PubMed

Zhang, Jixiang; Wu, Dandan; Vikash; Song, Jia; Wang, Jing; Yi, Jiasheng; Dong, Weiguo

2015-10-01

Hesperetin, has been shown to exert biological activities on various types of human cancers. However, few related studies on gastric cancer are available. In this study, we sought to investigate the effect of hesperetin on gastric cancer and clarify its specific mechanism. Cell Counting Kit-8, 2',7'-dichlorofluorescin diacetate, JC-1, Hoechst 33258 staining, and western bolt were used to detect cell viability, levels of intracellular reactive oxygen species (ROS), changes in mitochondrial membrane potential (△ψ m), cell apoptosis, and expressions of mitochondrial pathway proteins, respectively. Meanwhile, xenograft tumor models in nude mice were made to evaluate the effect of hesperetin on gastric cancer in vivo. Compared with the control group, the proliferation of gastric cancer cells in hesperetin groups was significantly inhibited (P < 0.05), and dose- and time-dependent effects were observed. Pretreatment with H2O2 (1 mM) or N-acetyl-L-cysteine (5 mM) enhanced or attenuated the hesperetin-induced inhibition of cell viability (P < 0.05). Percentages of apoptotic cells, levels of intracellular ROS, and △ψ m varied with the dose and treatment time of hesperetin (P < 0.05), and hesperetin caused an increase in the levels of AIF, Apaf-1, Cyt C, caspase-3, caspase-9, and Bax and a decrease in Bcl-2 levels (P < 0.05). Meanwhile, hesperetin significantly inhibited the growth of xenograft tumors (P < 0.05). Our study suggests that hesperetin could inhibit the proliferation and induce the apoptosis of gastric cancer cells via activating the mitochondrial pathway by increasing the ROS.

Astragaloside IV attenuates experimental autoimmune encephalomyelitis of mice by counteracting oxidative stress at multiple levels.

PubMed

He, Yixin; Du, Min; Gao, Yan; Liu, Hongshuai; Wang, Hongwei; Wu, Xiaojun; Wang, Zhengtao

2013-01-01

Multiple sclerosis (MS) is a chronic autoimmune neuroinflammatory disease found mostly in young adults in the western world. Oxidative stress induced neuronal apoptosis plays an important role in the pathogenesis of MS. In current study, astragaloside IV (ASI), a natural saponin molecule isolated from Astragalus membranceus, given at 20 mg/kg daily attenuated the severity of experimental autoimmune encephalomyelitis (EAE) in mice significantly. Further studies disclosed that ASI treatment inhibited the increase of ROS and pro-inflammatory cytokine levels, down-regulation of SOD and GSH-Px activities, and elevation of iNOS, p53 and phosphorylated tau in central nervous system (CNS) as well as the leakage of BBB of EAE mice. Meanwhile, the decreased ratio of Bcl-2/Bax was reversed by ASI. Moreover, ASI regulated T-cell differentiation and infiltration into CNS. In neuroblast SH-SY5Y cells, ASI dose-dependently reduced cellular ROS level and phosphorylation of tau in response to hydrogen peroxide challenge by modulation of Bcl-2/Bax ratio. ASI also inhibited activation of microglia both in vivo and in vitro. iNOS up-regulation induced by IFNγ stimulation was abolished by ASI dose-dependently in BV-2 cells. In summary, ASI prevented the severity of EAE progression possibly by counterbalancing oxidative stress and its effects via reduction of cellular ROS level, enhancement of antioxidant defense system, increase of anti-apoptotic and anti-inflammatory pathways, as well as modulation of T-cell differentiation and infiltration into CNS. The study suggested ASI may be effective for clinical therapy/prevention of MS.

Aflatoxin biosynthesis is a novel source of reactive oxygen species--a potential redox signal to initiate resistance to oxidative stress?

PubMed

Roze, Ludmila V; Laivenieks, Maris; Hong, Sung-Yong; Wee, Josephine; Wong, Shu-Shyan; Vanos, Benjamin; Awad, Deena; Ehrlich, Kenneth C; Linz, John E

2015-04-28

Aflatoxin biosynthesis in the filamentous fungus Aspergillus parasiticus involves a minimum of 21 enzymes, encoded by genes located in a 70 kb gene cluster. For aflatoxin biosynthesis to be completed, the required enzymes must be transported to specialized early and late endosomes called aflatoxisomes. Of particular significance, seven aflatoxin biosynthetic enzymes are P450/monooxygenases which catalyze reactions that can produce reactive oxygen species (ROS) as byproducts. Thus, oxidative reactions in the aflatoxin biosynthetic pathway could potentially be an additional source of intracellular ROS. The present work explores the hypothesis that the aflatoxin biosynthetic pathway generates ROS (designated as "secondary" ROS) in endosomes and that secondary ROS possess a signaling function. We used specific dyes that stain ROS in live cells and demonstrated that intracellular ROS levels correlate with the levels of aflatoxin synthesized. Moreover, feeding protoplasts with precursors of aflatoxin resulted in the increase in ROS generation. These data support the hypothesis. Our findings also suggest that secondary ROS may fulfill, at least in part, an important mechanistic role in increased tolerance to oxidative stress in germinating spores (seven-hour germlings) and in regulation of fungal development.

Aflatoxin Biosynthesis Is a Novel Source of Reactive Oxygen Species—A Potential Redox Signal to Initiate Resistance to Oxidative Stress?

PubMed Central

Roze, Ludmila V.; Laivenieks, Maris; Hong, Sung-Yong; Wee, Josephine; Wong, Shu-Shyan; Vanos, Benjamin; Awad, Deena; Ehrlich, Kenneth C.; Linz, John E.

2015-01-01

Aflatoxin biosynthesis in the filamentous fungus Aspergillus parasiticus involves a minimum of 21 enzymes, encoded by genes located in a 70 kb gene cluster. For aflatoxin biosynthesis to be completed, the required enzymes must be transported to specialized early and late endosomes called aflatoxisomes. Of particular significance, seven aflatoxin biosynthetic enzymes are P450/monooxygenases which catalyze reactions that can produce reactive oxygen species (ROS) as byproducts. Thus, oxidative reactions in the aflatoxin biosynthetic pathway could potentially be an additional source of intracellular ROS. The present work explores the hypothesis that the aflatoxin biosynthetic pathway generates ROS (designated as “secondary” ROS) in endosomes and that secondary ROS possess a signaling function. We used specific dyes that stain ROS in live cells and demonstrated that intracellular ROS levels correlate with the levels of aflatoxin synthesized. Moreover, feeding protoplasts with precursors of aflatoxin resulted in the increase in ROS generation. These data support the hypothesis. Our findings also suggest that secondary ROS may fulfill, at least in part, an important mechanistic role in increased tolerance to oxidative stress in germinating spores (seven-hour germlings) and in regulation of fungal development. PMID:25928133

Decursin enhances TRAIL‐induced apoptosis through oxidative stress mediated‐ endoplasmic reticulum stress signalling in non‐small cell lung cancers

PubMed Central

Kim, Jaekwang; Yun, Miyong; Kim, Eun‐Ok; Jung, Deok‐Beom; Won, Gunho; Kim, Bonglee; Jung, Ji Hoon

2016-01-01

Background and Purpose The TNF‐related apoptosis‐inducing ligand (TRAIL) is a promising anticancer agent due to its remarkable ability to selectively kill tumour cells. However, because most tumours exhibit resistance to TRAIL‐induced apoptosis, the development of combination therapies to overcome resistance to TRAIL is required for effective cancer therapy. Experimental Approach Cell viability and possible synergy between the plant pyranocoumarin decursin and TRAIL was measured by MTT assay and calcusyn software. Reactive oxygen species (ROS) and apoptosis were measured using dichlorodihydrofluorescein and annexin/propidium iodide in cell flow cytometry. Changes in protein levels were assessed with Western blotting. Key Results Combining decursin and TRAIL markedly decreased cell viability and increased apoptosis in TRAIL‐resistant non‐small‐cell lung cancer (NSCLC) cell lines. Decursin induced expression of the death receptor 5 (DR5). Inhibition of DR5 attenuated apoptotic cell death in decursin + TRAIL treated NSCLC cell lines. Interestingly, induction of DR5 and CCAAT/enhancer‐binding protein homologues protein by decursin was mediated through selective induction of the pancreatic endoplasmic reticulum kinase (PERK)/activating transcription factor 4 (ATF4) branch of the endoplasmic reticulum stress response pathway. Furthermore, enhancement of PERK/ATF4 signalling by decursin was mediated by ROS generation in NSCLC cell lines, but not in normal human lung cells. Decursin also markedly down‐regulated expression of survivin and Bcl‐xL in TRAIL‐resistant NSCLC cells. Conclusions and Implications ROS generation by decursin selectively activated the PERK/ATF4 axis of the endoplasmic reticulum stress signalling pathway, leading to enhanced TRAIL sensitivity in TRAIL‐resistant NSCLC cell lines, partly via up‐regulation of DR5. PMID:26661339

Ofloxacin induces apoptosis via β1 integrin-EGFR-Rac1-Nox2 pathway in microencapsulated chondrocytes

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

Sheng, Zhi-Guo; Huang, Wei; Liu, Yu-Xiang

2013-02-15

Quinolones (QNs)-induced arthropathy is an important toxic side-effect in immature animals leading to the restriction of their therapeutic use in pediatrics. Ofloxacin, a typical QN, was found to induce the chondrocytes apoptosis in the early phase (12–48 h) of arthropathy in our previous study. However, the exact mechanism(s) is unclear. Microencapsulated juvenile rabbit joint chondrocytes, a three-dimensional culture system, is utilized to perform the present study. Ofloxacin, at a therapeutically relevant concentration (10 μg/ml), disturbs the interaction between β1 integrin and activated intracellular signaling proteins at 12 h, which is inhibited when supplementing Mg{sup 2+}. Intracellular reactive oxygen species (ROS)more » significantly increases in a time-dependent manner after exposure to ofloxacin for 12–48 h. Furthermore, ofloxacin markedly enhances the level of activated Rac1 and epidermal growth factor receptor (EGFR) phosphorylation, and its inhibition in turn reduces the ROS production, apoptosis and Rac1 activation. Silencing Nox2, Rac1 or supplementing Mg{sup 2+} inhibits ROS accumulation, apoptosis occurrence and EGFR phosphorylation induced by ofloxacin. However, depletion of Nox2, Rac1 and inhibition of EGFR do not affect ofloxacin-mediated loss of interaction between β1 integrin and activated intracellular signaling proteins. In addition, ofloxacin also induces Vav2 phosphorylation, which is markedly suppressed after inactivating EGFR or supplementing Mg{sup 2+}. These results suggest that ofloxacin causes Nox2-mediated intracellular ROS production by disrupting the β1 integrin function and then activating the EGFR-Vav2-Rac1 pathway, finally resulting in apoptosis within 12–48 h exposure. The present study provides a novel insight regarding the potential role of Nox-driven ROS in QNs-induced arthropathy. - Highlights: ► Ofloxacin induces Nox2-driven ROS in encapsulated chondrocyte at 12–48 h. ► Ofloxacin stimulates ROS production via the β1 integrin-EGFR-Vav2-Rac1 pathway. ► Ofloxacin induces ROS-dependent apoptosis in encapsulated chondrocyte at 12–48 h.« less

Homocysteine activates T cells by enhancing endoplasmic reticulum-mitochondria coupling and increasing mitochondrial respiration.

PubMed

Feng, Juan; Lü, Silin; Ding, Yanhong; Zheng, Ming; Wang, Xian

2016-06-01

Hyperhomocysteinemia (HHcy) accelerates atherosclerosis by increasing proliferation and stimulating cytokine secretion in T cells. However, whether homocysteine (Hcy)-mediated T cell activation is associated with metabolic reprogramming is unclear. Here, our in vivo and in vitro studies showed that Hcy-stimulated splenic T-cell activation in mice was accompanied by increased levels of mitochondrial reactive oxygen species (ROS) and calcium, mitochondrial mass and respiration. Inhibiting mitochondrial ROS production and calcium signals or blocking mitochondrial respiration largely blunted Hcy-induced T-cell interferon γ (IFN-γ) secretion and proliferation. Hcy also enhanced endoplasmic reticulum (ER) stress in T cells, and inhibition of ER stress with 4-phenylbutyric acid blocked Hcy-induced T-cell activation. Mechanistically, Hcy increased ER-mitochondria coupling, and uncoupling ER-mitochondria by the microtubule inhibitor nocodazole attenuated Hcy-stimulated mitochondrial reprogramming, IFN-γ secretion and proliferation in T cells, suggesting that juxtaposition of ER and mitochondria is required for Hcy-promoted mitochondrial function and T-cell activation. In conclusion, Hcy promotes T-cell activation by increasing ER-mitochondria coupling and regulating metabolic reprogramming.

Human Chorionic Gonadotropin Mediated Generation of Reactive Oxygen Species Is Sufficient to Induce Meiotic Exit but Not Apoptosis in Rat Oocytes

PubMed Central

Tiwari, Meenakshi; Chaube, Shail K.

2017-01-01

Abstract Generation of reactive oxygen species (ROS) is associated with final stages of follicular development and ovulation in mammals. The human chorionic gonadotropin (hCG) mimics the action of luteinizing hormone and triggers follicular development and ovulation. However, it remains unclear whether hCG induces generation of ROS, if yes, whether hCG-mediated increased level of ROS could induce meiotic exit and/or apoptosis in rat oocytes. For this purpose, cumulus–oocyte complexes (COCs) were collected from ovary of experimental rats injected with 20 IU pregnant mare's serum gonadotropin for 48 h followed by 20 IU hCG for 0, 7, 14, and 21 h. The morphological changes in COCs, meiotic status of oocyte, total ROS, hydrogen peroxide (H2O2), inducible nitric oxide synthase (iNOS), nitric oxide (NO), Bax, Bcl-2, cytochrome c, telomerase reverse transcriptase (TERT) expression levels, and DNA fragmentation were analyzed in COCs. Our data suggest that hCG surge increased total ROS as well as H2O2 levels but decreased iNOS expression and total NO level in oocytes. The hCG-mediated increased level of ROS was sufficient to induce meiotic cell cycle resumption in majority of oocytes as evidenced by meiotic exit from diplotene as well as metaphase-II (M-II) arrest and their meiotic status. However, increase of ROS level due to hCG surge was not sufficient to trigger Bax and cytochrome c expression levels and DNA fragmentation in COCs. In addition, increased TERT activity was observed in oocytes collected 21 h post-hCG surge showing onset of oocyte aging. Taken together, these results suggest that hCG induces generation of ROS sufficient to trigger meiotic exit from diplotene, as well as M-II arrest, but not good enough to induce apoptosis in rat oocytes. PMID:29098117

Mitochondrial redox plays a critical role in the paradoxical effects of NAPDH oxidase-derived ROS on coronary endothelium

PubMed Central

Shafique, Ehtesham; Torina, Anali; Reichert, Karla; Colantuono, Bonnie; Nur, Nasifa; Zeeshan, Khawaja; Ravichandran, Vani; Liu, Yuhong; Feng, Jun; Zeeshan, Khawaja; Benjamin, Laura E.; Irani, Kaikobad; Harrington, Elizabeth O.; Sellke, Frank W.; Abid, Md. Ruhul

2017-01-01

Aims There are conflicting reports on the role of reactive oxygen species (ROS) i.e. beneficial vs. harmful, in vascular endothelium. Here, we aim to examine whether duration of exposure to ROS and/or subcellular ROS levels are responsible for the apparently paradoxical effects of oxidants on endothelium. Methods and results We have recently generated binary (Tet-ON/OFF) conditional transgenic mice (Tet-Nox2:VE-Cad-tTA) that can induce 1.8 ± 0.42-fold increase in NADPH oxidase (NOX)-derived ROS specifically in vascular endothelium upon withdrawal of tetracycline from the drinking water. Animals were divided in two groups: one exposed to high endogenous ROS levels for 8 weeks (short-term) and the other for 20 weeks (long-term). Using endothelial cells (EC) isolated from mouse hearts (MHEC), we demonstrate that both short-term and long-term increase in NOX-ROS induced AMPK-mediated activation of eNOS. Interestingly, although endothelium-dependent nitric oxide (NO)-mediated coronary vasodilation was significantly increased after short-term increase in NOX-ROS, coronary vasodilation was drastically reduced after long-term increase in ROS. We also show that short-term ROS increase induced proliferation in EC and angiogenic sprouting in the aorta. In contrast, long-term increase in cytosolic ROS resulted in nitrotyrosine-mediated inactivation of mitochondrial (mito) antioxidant MnSOD, increase in mito-ROS, loss of mitochondrial membrane potential (Δψm), decreased EC proliferation and angiogenesis. Conclusion The findings suggest that NOX-derived ROS results in increased mito-ROS. Whereas short-term increase in mito-ROS was counteracted by MnSOD, long-term increase in ROS resulted in nitrotyrosine-mediated inactivation of MnSOD, leading to unchecked increase in mito-ROS and loss of Δψm followed by inhibition of endothelial function and proliferation. PMID:28088753

Loss of autophagy enhances MIF/macrophage migration inhibitory factor release by macrophages.

PubMed

Lee, Jacinta P W; Foote, Andrew; Fan, Huapeng; Peral de Castro, Celia; Lang, Tali; Jones, Sarah A; Gavrilescu, Nichita; Mills, Kingston H G; Leech, Michelle; Morand, Eric F; Harris, James

2016-06-02

MIF (macrophage migration inhibitory factor [glycosylation-inhibiting factor]) is a pro-inflammatory cytokine expressed in multiple cells types, including macrophages. MIF plays a pathogenic role in a number of inflammatory diseases and has been linked to tumor progression in some cancers. Previous work has demonstrated that loss of autophagy in macrophages enhances secretion of IL1 family cytokines. Here, we demonstrate that loss of autophagy, by pharmacological inhibition or siRNA silencing of Atg5, enhances MIF secretion by monocytes and macrophages. We further demonstrate that this is dependent on mitochondrial reactive oxygen species (ROS). Induction of autophagy with MTOR inhibitors had no effect on MIF secretion, but amino acid starvation increased secretion. This was unaffected by Atg5 siRNA but was again dependent on mitochondrial ROS. Our data demonstrate that autophagic regulation of mitochondrial ROS plays a pivotal role in the regulation of inflammatory cytokine secretion in macrophages, with potential implications for the pathogenesis of inflammatory diseases and cancers.

Suitable Concentrations of Uric Acid Can Reduce Cell Death in Models of OGD and Cerebral Ischemia-Reperfusion Injury.

PubMed

Zhang, Bin; Yang, Ning; Lin, Shao-Peng; Zhang, Feng

2017-07-01

Cerebral infarction (CI) is a common clinical cerebrovascular disease, and to explore the pathophysiological mechanisms and seek effective treatment means are the hotspot and difficult point in medical research nowadays. Numerous studies have confirmed that uric acid plays an important role in CI, but the mechanism has not yet been clarified. When treating HT22 and BV-2 cells with different concentrations of uric acid, uric acid below 450 μM does not have significant effect on cell viability, but uric acid more than 500 μM can significantly inhibit cell viability. After establishing models of OGD (oxygen-glucose deprivation) with HT22 and BV-2 cells, uric acid at a low concentration (50 μM) cannot improve cell viability and apoptosis, and Reactive oxygen species (ROS) levels during OGD/reoxygenation; a suitable concentration (300 μM) of uric acid can significantly improve cell viability and apoptosis, and reduce ROS production during OGD/reoxygenation; but a high concentration (1000 μM) of uric acid can further reduce cell viability and enhance ROS production. After establishing middle cerebral artery occlusion of male rats with suture method, damage and increase of ROS production in brain tissue could be seen, and after adding suitable concentration of uric acid, the degree of brain damage and ROS production was reduced. Therefore, different concentrations of uric acid should have different effect, and suitable concentrations of uric acid have neuroprotective effect, and this finding may provide guidance for study on the clinical curative effect of uric acid.

Protective effect of mitochondrial-targeted antioxidant MitoQ against iron ion 56Fe radiation induced brain injury in mice.

PubMed

Gan, Lu; Wang, Zhenhua; Si, Jing; Zhou, Rong; Sun, Chao; Liu, Yang; Ye, Yancheng; Zhang, Yanshan; Liu, Zhiyuan; Zhang, Hong

2018-02-15

Exposure to iron ion 56 Fe radiation (IR) during space missions poses a significant risk to the central nervous system and radiation exposure is intimately linked to the production of reactive oxygen species (ROS). MitoQ is a mitochondria-targeted antioxidant that has been shown to decrease oxidative damage and lower mitochondrial ROS in a number of animal models. Therefore, the present study aimed to investigate role of the mitochondrial targeted antioxidant MitoQ against 56 Fe particle irradiation-induced oxidative damage and mitochondria dysfunction in the mouse brains. Increased ROS levels were observed in mouse brains after IR compared with the control group. Enhanced ROS production leads to disruption of cellular antioxidant defense systems, mitochondrial respiration dysfunction, altered mitochondria dynamics and increased release of cytochrome c (cyto c) from mitochondria into cytosol resulting in apoptotic cell death. MitoQ reduced IR-induced oxidative stress (decreased ROS production and increased SOD, CAT activities) with decreased lipid peroxidation as well as reduced protein and DNA oxidation. MitoQ also protected mitochondrial respiration after IR. In addition, MitoQ increased the expression of mitofusin2 (Mfn2) and optic atrophy gene1 (OPA1), and decreased the expression of dynamic-like protein (Drp1). MitoQ also suppressed mitochondrial DNA damage, cyto c release, and caspase-3 activity in IR-treated mice compared to the control group. These results demonstrate that MitoQ may protect against IR-induced brain injury. Copyright © 2018 Elsevier Inc. All rights reserved.

Chemical genetics analysis of an aniline mustard anticancer agent reveals complex I of the electron transport chain as a target.

PubMed

Fedeles, Bogdan I; Zhu, Angela Y; Young, Kellie S; Hillier, Shawn M; Proffitt, Kyle D; Essigmann, John M; Croy, Robert G

2011-09-30

The antitumor agent 11β (CAS 865070-37-7), consisting of a DNA-damaging aniline mustard linked to an androgen receptor (AR) ligand, is known to form covalent DNA adducts and to induce apoptosis potently in AR-positive prostate cancer cells in vitro; it also strongly prevents growth of LNCaP xenografts in mice. The present study describes the unexpectedly strong activity of 11β against the AR-negative HeLa cells, both in cell culture and tumor xenografts, and uncovers a new mechanism of action that likely explains this activity. Cellular fractionation experiments indicated that mitochondria are the major intracellular sink for 11β; flow cytometry studies showed that 11β exposure rapidly induced oxidative stress, mitochondria being an important source of reactive oxygen species (ROS). Additionally, 11β inhibited oxygen consumption both in intact HeLa cells and in isolated mitochondria. Specifically, 11β blocked uncoupled oxygen consumption when mitochondria were incubated with complex I substrates, but it had no effect on oxygen consumption driven by substrates acting downstream of complex I in the mitochondrial electron transport chain. Moreover, 11β enhanced ROS generation in isolated mitochondria, suggesting that complex I inhibition is responsible for ROS production. At the cellular level, the presence of antioxidants (N-acetylcysteine or vitamin E) significantly reduced the toxicity of 11β, implicating ROS production as an important contributor to cytotoxicity. Collectively, our findings establish complex I inhibition and ROS generation as a new mechanism of action for 11β, which supplements conventional DNA adduct formation to promote cancer cell death.

Shear-induced endothelial mechanotransduction: the interplay between reactive oxygen species (ROS) and nitric oxide (NO) and the pathophysiological implications

PubMed Central

2014-01-01

Hemodynamic shear stress, the blood flow-generated frictional force acting on the vascular endothelial cells, is essential for endothelial homeostasis under normal physiological conditions. Mechanosensors on endothelial cells detect shear stress and transduce it into biochemical signals to trigger vascular adaptive responses. Among the various shear-induced signaling molecules, reactive oxygen species (ROS) and nitric oxide (NO) have been implicated in vascular homeostasis and diseases. In this review, we explore the molecular, cellular, and vascular processes arising from shear-induced signaling (mechanotransduction) with emphasis on the roles of ROS and NO, and also discuss the mechanisms that may lead to excessive vascular remodeling and thus drive pathobiologic processes responsible for atherosclerosis. Current evidence suggests that NADPH oxidase is one of main cellular sources of ROS generation in endothelial cells under flow condition. Flow patterns and magnitude of shear determine the amount of ROS produced by endothelial cells, usually an irregular flow pattern (disturbed or oscillatory) producing higher levels of ROS than a regular flow pattern (steady or pulsatile). ROS production is closely linked to NO generation and elevated levels of ROS lead to low NO bioavailability, as is often observed in endothelial cells exposed to irregular flow. The low NO bioavailability is partly caused by the reaction of ROS with NO to form peroxynitrite, a key molecule which may initiate many pro-atherogenic events. This differential production of ROS and RNS (reactive nitrogen species) under various flow patterns and conditions modulates endothelial gene expression and thus results in differential vascular responses. Moreover, ROS/RNS are able to promote specific post-translational modifications in regulatory proteins (including S-glutathionylation, S-nitrosylation and tyrosine nitration), which constitute chemical signals that are relevant in cardiovascular pathophysiology. Overall, the dynamic interplay between local hemodynamic milieu and the resulting oxidative and S-nitrosative modification of regulatory proteins is important for ensuing vascular homeostasis. Based on available evidence, it is proposed that a regular flow pattern produces lower levels of ROS and higher NO bioavailability, creating an anti-atherogenic environment. On the other hand, an irregular flow pattern results in higher levels of ROS and yet lower NO bioavailability, thus triggering pro-atherogenic effects. PMID:24410814

Spatial and seasonal heterogeneity of atmospheric particles induced reactive oxygen species in urban areas and the role of water-soluble metals.

PubMed

Gali, Nirmal Kumar; Yang, Fenhuan; Jiang, Sabrina Yanan; Chan, Ka Lok; Sun, Li; Ho, Kin-fai; Ning, Zhi

2015-03-01

Adverse health effects are associated with exposure to atmospheric particulate matter (PM), which carry various chemical constituents and induce both exogenous and endogenous oxidative stress. This study investigated the spatial and seasonal variability of PM-induced ROS at four sites with different characteristics in Hong Kong. Cytotoxicity, exogenous and endogenous ROS was determined on a dose and time dependent analysis. Large spatial variation of ROS was observed with fine PM at urban site showing highest ROS levels while coarse PM at traffic site ranks the top. No consistent seasonal difference was observed for ROS levels among all sites. The highly heterogeneous distribution of PM-induced ROS demonstrates the differential capability of PM to produce oxidative stress, and the need to use appropriate metrics as surrogates of exposure instead of PM mass in epidemiologic studies. Several transition metals were found associated with ROS by different degree illustrating the complexity of mechanisms involved. Copyright © 2015 Elsevier Ltd. All rights reserved.

[Comparison of seminal vitamin B12, folate, reactive oxygen species and various sperm parameters between fertile and infertile males].

PubMed

Chen, Q; Ng, V; Mei, J; Chia, S E

2001-03-01

Vitamin B12(VB12), folate and reactive oxygen species(ROS) in human semen from both fertile and infertile males, and their relationships with other parameters were observed. Semen samples from 44 infertile and 176 fentile control subjects were collected and measured based on the guidelines issued by WHO. The results showed that no significant differences on semen VB12 and folate were observed between fertile and infertile groups(P > 0.05). However, the levels of ROS in infertile group were significantly higher than those in fertile group(P < 0.01). The morphological defects and low motility of sperm in infertile group was significantly higher than those in fertile group(P < 0.01). A positive relation was observed between the levels of ROS production and the morphological defect of sperm(P < 0.01). There was a significant negative correlation between the levels of VB12, folate and ROS(P < 0.01) in semen. It is interesting to note that the values of ROS also show a significantly positive correlation with sperm motility (P < 0.01). A significant differences of ROS levels between fertile and infertile group with negative white blood cells in sperm was also observed. It is concluded that the increase of ROS on the morphological defect of sperm is one of the most important factors related to poor sperm quality and human infertility.

Reactive oxygen species formation and bystander effects in gradient irradiation on human breast cancer cells.

PubMed

Zhang, Dongqing; Zhou, Tingyang; He, Feng; Rong, Yi; Lee, Shin Hee; Wu, Shiyong; Zuo, Li

2016-07-05

Ionizing radiation (IR) in cancer radiotherapy can induce damage to neighboring cells via non-targeted effects by irradiated cells. These so-called bystander effects remain an area of interest as it may provide enhanced efficacy in killing carcinomas with minimal radiation. It is well known that reactive oxygen species (ROS) are ubiquitous among most biological activities. However, the role of ROS in bystander effects has not been thoroughly elucidated. We hypothesized that gradient irradiation (GI) has enhanced therapeutic effects via the ROS-mediated bystander pathways as compared to uniform irradiation (UI). We evaluated ROS generation, viability, and apoptosis in breast cancer cells (MCF-7) exposed to UI (5 Gy) or GI (8-2 Gy) in radiation fields at 2, 24 and 48 h after IR. We found that extracellular ROS release induced by GI was higher than that by UI at both 24 h (p < 0.001) and 48 h (p < 0.001). More apoptosis and less viability were observed in GI when compared to UI at either 24 h or 48 h after irradiation. The mean effective doses (ED) of GI were ~130% (24 h) and ~48% (48 h) higher than that of UI, respectively. Our results suggest that GI is superior to UI regarding redox mechanisms, ED, and toxic dosage to surrounding tissues.

Inhibiting ROS-TFEB-Dependent Autophagy Enhances Salidroside-Induced Apoptosis in Human Chondrosarcoma Cells.

PubMed

Zeng, Wei; Xiao, Tao; Cai, Anlie; Cai, Weiliang; Liu, Huanhuan; Liu, Jingling; Li, Jie; Tan, Miduo; Xie, Li; Liu, Ying; Yang, Xiangcheng; Long, Yi

2017-01-01

Autophagy modulation has been considered a potential therapeutic strategy for human chondrosarcoma, and a previous study indicated that salidroside exhibits significant anti-carcinogenic activity. However, the ability of salidroside to induce autophagy and its role in human chondrosarcoma cell death remains unclear. We exposed SW1353 cells to different concentrations of salidroside (0.5, 1 and 2 mM) for 24 h. RT-PCR, Western-blotting, Immunocytofluorescence, and Luciferase Reporter Assays were used to evaluate whether salidroside activated the TFEB-dependent autophagy. We show that salidroside induced significant apoptosis in the human chondrosarcoma cell line SW1353. In addition, we demonstrate that salidroside-induced an autophagic response in SW1353 cells, as evidenced by the upregulation of LC3-II and downregulation of P62. Moreover, pharmacological or genetic blocking of autophagy enhanced salidroside -induced apoptosis, indicating the cytoprotective role of autophagy in salidroside-treated SW1353 cells. Salidroside also induced TFEB (Ser142) dephosphorylation, subsequently to activated TFEB nuclear translocation and increase of TFEB reporter activity, which contributed to lysosomal biogenesis and the expression of autophagy-related genes. Importantly, we found that salidroside triggered the generation of ROS in SW1353 cells. Furthermore, NAC, a ROS scavenger, abrogated the effects of salidroside on TFEB-dependent autophagy. These data demonstrate that salidroside increased TFEB-dependent autophagy by activating ROS signaling pathways in human chondrosarcoma cells. These data also suggest that blocking ROS-TFEB-dependent autophagy to enhance the activity of salidroside warrants further attention in treatment of human chondrosarcoma cells. © 2017 The Author(s). Published by S. Karger AG, Basel.

Gelidium elegans, an edible red seaweed, and hesperidin inhibit lipid accumulation and production of reactive oxygen species and reactive nitrogen species in 3T3-L1 and RAW264.7 cells.

PubMed

Jeon, Hui-Jeon; Seo, Min-Jung; Choi, Hyeon-Son; Lee, Ok-Hwan; Lee, Boo-Yong

2014-11-01

Gelidium elegans is an edible red alga native to the intertidal area of northeastern Asia. We investigated the effect of G. elegans extract and its main flavonoids, rutin and hesperidin, on lipid accumulation and the production of reactive oxygen species (ROS) and reactive nitrogen species (RNS) in 3T3-L1 and RAW264.7 cells. Our data show that G. elegans extract decreased lipid accumulation and ROS/RNS production in a dose-dependent manner. The extract also inhibited the mRNA expression of adipogenic transcription factors, such as peroxisome proliferator-activated receptor gamma and CCAAT/enhancer-binding protein alpha, while enhancing the protein expression of the antioxidant enzymes superoxide dismutases 1 and 2, glutathione peroxidase, and glutathione reductase compared with controls. In addition, lipopolysaccharide-induced nitric oxide production was significantly reduced in G. elegans extract-treated RAW264.7 cells. In analysis of the effects of G. elegans flavonoids on lipid accumulation and ROS/RNS production, only hesperidin showed an inhibitory effect on lipid accumulation and ROS production; rutin did not affect adipogenesis and ROS status. The antiadipogenic effect of hesperidin was evidenced by the downregulation of peroxisome proliferator-activated receptor gamma, CCAAT/enhancer-binding protein alpha, and fatty acid binding protein 4 gene expression. Collectively, our data suggest that G. elegans is a potential food source containing antiobesity and antioxidant constituents. Copyright © 2014 John Wiley & Sons, Ltd.

Non-thermal dielectric barrier discharge plasma induces angiogenesis through reactive oxygen species.

PubMed

Arjunan, Krishna Priya; Friedman, Gary; Fridman, Alexander; Clyne, Alisa Morss

2012-01-07

Vascularization plays a key role in processes such as wound healing and tissue engineering. Non-thermal plasma, which primarily produces reactive oxygen species (ROS), has recently emerged as an efficient tool in medical applications including blood coagulation, sterilization and malignant cell apoptosis. Liquids and porcine aortic endothelial cells were treated with a non-thermal dielectric barrier discharge plasma in vitro. Plasma treatment of phosphate-buffered saline (PBS) and serum-free medium increased ROS concentration in a dose-dependent manner, with a higher concentration observed in serum-free medium compared with PBS. Species concentration inside cells peaked 1 h after treatment, followed by a decrease 3 h post treatment. Endothelial cells treated with a plasma dose of 4.2 J cm(-2) had 1.7 times more cells than untreated samples 5 days after plasma treatment. The 4.2 J cm(-2) plasma dose increased two-dimensional migration distance by 40 per cent compared with untreated control, while the number of cells that migrated through a three-dimensional collagen gel increased by 15 per cent. Tube formation was also enhanced by plasma treatment, with tube lengths in plasma-treated samples measuring 2.6 times longer than control samples. A fibroblast growth factor-2 (FGF-2) neutralizing antibody and ROS scavengers abrogated these angiogenic effects. These data indicate that plasma enhanced proliferation, migration and tube formation is due to FGF-2 release induced by plasma-produced ROS. Non-thermal plasma may be used as a potential tool for applying ROS in precise doses to enhance vascularization.

Non-thermal dielectric barrier discharge plasma induces angiogenesis through reactive oxygen species

PubMed Central

Arjunan, Krishna Priya; Friedman, Gary; Fridman, Alexander; Clyne, Alisa Morss

2012-01-01

Vascularization plays a key role in processes such as wound healing and tissue engineering. Non-thermal plasma, which primarily produces reactive oxygen species (ROS), has recently emerged as an efficient tool in medical applications including blood coagulation, sterilization and malignant cell apoptosis. Liquids and porcine aortic endothelial cells were treated with a non-thermal dielectric barrier discharge plasma in vitro. Plasma treatment of phosphate-buffered saline (PBS) and serum-free medium increased ROS concentration in a dose-dependent manner, with a higher concentration observed in serum-free medium compared with PBS. Species concentration inside cells peaked 1 h after treatment, followed by a decrease 3 h post treatment. Endothelial cells treated with a plasma dose of 4.2 J cm–2 had 1.7 times more cells than untreated samples 5 days after plasma treatment. The 4.2 J cm–2 plasma dose increased two-dimensional migration distance by 40 per cent compared with untreated control, while the number of cells that migrated through a three-dimensional collagen gel increased by 15 per cent. Tube formation was also enhanced by plasma treatment, with tube lengths in plasma-treated samples measuring 2.6 times longer than control samples. A fibroblast growth factor-2 (FGF-2) neutralizing antibody and ROS scavengers abrogated these angiogenic effects. These data indicate that plasma enhanced proliferation, migration and tube formation is due to FGF-2 release induced by plasma-produced ROS. Non-thermal plasma may be used as a potential tool for applying ROS in precise doses to enhance vascularization. PMID:21653568

Effect of uric acid on inflammatory COX-2 and ROS pathways in vascular smooth muscle cells.

PubMed

Oğuz, Nurgül; Kırça, Mustafa; Çetin, Arzu; Yeşilkaya, Akın

2017-10-01

Hyperuricemia is thought to play a role in cardiovascular diseases (CVD), including hypertension, coronary artery disease and atherosclerosis. However, exactly how uric acid contributes to these pathologies is unknown. An underlying mechanism of inflammatory diseases, such as atherosclerosis, includes enhanced production of cyclooxygenase-2 (COX-2) and superoxide anion. Here, we aimed to examine the effect of uric acid on inflammatory COX-2 and superoxide anion production and to determine the role of losartan. Primarily cultured vascular smooth muscle cells (VSMCs) were time and dose-dependently induced by uric acid and COX-2 and superoxide anion levels were measured. COX-2 levels were determined by ELISA, and superoxide anion was measured by the superoxide dismutase (SOD)-inhibitable reduction of ferricytochrome c method. Uric acid elevated COX-2 levels in a time-dependent manner. Angiotensin-II receptor blocker, losartan, diminished uric-acid-induced COX-2 elevation. Uric acid also increased superoxide anion level in VSMCs. Uric acid plays an important role in CVD pathogenesis by inducing inflammatory COX-2 and ROS pathways. This is the first study demonstrating losartan's ability to reduce uric-acid-induced COX-2 elevation.

Antioxidative study of Cerium Oxide nanoparticle functionalised PCL-Gelatin electrospun fibers for wound healing application.

PubMed

Rather, Hilal Ahmad; Thakore, Ria; Singh, Ragini; Jhala, Dhwani; Singh, Sanjay; Vasita, Rajesh

2018-06-01

Skin wound healing involves a coordinated cellular response to achieve complete reepithelialisation. Elevated levels of reactive oxygen species (ROS) in the wound environment often pose a hindrance in wound healing resulting in impaired wound healing process. Cerium oxide nanoparticles (CeNPs) have the ability to protect the cells from oxidative damage by actively scavenging the ROS. Furthermore, matrices like nanofibers have also been explored for enhancing wound healing. In the current study CeNP functionalised polycaprolactone (PCL)-gelatin nanofiber (PGNPNF) mesh was fabricated by electrospinning and evaluated for its antioxidative potential. Wide angle XRD analysis of randomly oriented nanofibers revealed ∼2.6 times reduced crystallinity than pristine PCL which aided in rapid degradation of nanofibers and release of CeNP. However, bioactive composite made between nanoparticles and PCL-gelatin maintained the fibrous morphology of PGNPNF upto 14 days. The PGNPNF mesh exhibited a superoxide dismutase (SOD) mimetic activity due to the incorporated CeNPs. The PGNPNF mesh enhanced proliferation of 3T3-L1 cells by ∼48% as confirmed by alamar blue assay and SEM micrographs of cells grown on the nanofibrous mesh. Furthermore, the PGNPNF mesh scavenged ROS, which was measured by relative DCF intensity and fluorescence microscopy; and subsequently increased the viability and proliferation of cells by three folds as it alleviated the oxidative stress. Overall, the results of this study suggest the potential of CeNP functionalised PCL-gelatin nanofibrous mesh for wound healing applications.

Exogenous calcium induces tolerance to atrazine stress in Pennisetum seedlings and promotes photosynthetic activity, antioxidant enzymes and psbA gene transcripts.

PubMed

Erinle, Kehinde Olajide; Jiang, Zhao; Ma, Bingbing; Li, Jinmei; Chen, Yukun; Ur-Rehman, Khalil; Shahla, Andleeb; Zhang, Ying

2016-10-01

Calcium (Ca) has been reported to lessen oxidative damages in plants by upregulating the activities of antioxidant enzymes. However, atrazine mediated reactive oxygen species (ROS) reduction by Ca is limited. This study therefore investigated the effect of exogenously applied Ca on ROS, antioxidants activity and gene transcripts, the D1 protein (psbA gene), and chlorophyll contents in Pennisetum seedlings pre-treated with atrazine. Atrazine toxicity increased ROS production and enzyme activities (ascorbate peroxidase APX, peroxidase POD, Superoxide dismutase SOD, glutathione-S-transferase GST); but decreased antioxidants (APX, POD, and Cu/Zn SOD) and psbA gene transcripts. Atrazine also decreased the chlorophyll contents, but increased chlorophyll (a/b) ratio. Contrarily, Ca application to atrazine pre-treated seedlings lowered the harmful effects of atrazine by reducing ROS levels, but enhancing the accumulation of total chlorophyll contents. Ca-protected seedlings in the presence of atrazine manifested reduced APX and POD activity, whereas SOD and GST activity was further increased with Ca application. Antioxidant gene transcripts that were down-regulated by atrazine toxicity were up-regulated with the application of Ca. Calcium application also resulted in up-regulation of the D1 protein. In conclusion, ability of calcium to reverse atrazine-induced oxidative damage and calcium regulatory role on GST in Pennisetum was presented. Copyright © 2016 Elsevier Inc. All rights reserved.

Acute ethanol exposure-induced autophagy-mediated cardiac injury via activation of the ROS-JNK-Bcl-2 pathway.

PubMed

Zhu, Zhongxin; Huang, Yewei; Lv, Lingchun; Tao, Youli; Shao, Minglong; Zhao, Congcong; Xue, Mei; Sun, Jia; Niu, Chao; Wang, Yang; Kim, Sunam; Cong, Weitao; Mao, Wei; Jin, Litai

2018-02-01

Binge drinking is associated with increased cardiac autophagy, and often triggers heart injury. Given the essential role of autophagy in various cardiac diseases, this study was designed to investigate the role of autophagy in ethanol-induced cardiac injury and the underlying mechanism. Our study showed that ethanol exposure enhanced the levels of LC3-II and LC3-II positive puncta and promoted cardiomyocyte apoptosis in vivo and in vitro. In addition, we found that ethanol induced autophagy and cardiac injury largely via the sequential triggering of reactive oxygen species (ROS) accumulation, activation of c-Jun NH2-terminal kinase (JNK), phosphorylation of Bcl-2, and dissociation of the Beclin 1/Bcl-2 complex. By contrast, inhibition of ethanol-induced autophagic flux with pharmacologic agents in the hearts of mice and cultured cells significantly alleviated ethanol-induced cardiomyocyte apoptosis and heart injury. Elimination of ROS with the antioxidant N-acetyl cysteine (NAC) or inhibition of JNK with the JNK inhibitor SP600125 reduced ethanol-induced autophagy and subsequent autophagy-mediated apoptosis. Moreover, metallothionein (MT), which can scavenge reactive oxygen and nitrogen species, also attenuated ethanol-induced autophagy and cell apoptosis in MT-TG mice. In conclusion, our findings suggest that acute ethanol exposure induced autophagy-mediated heart toxicity and injury mainly through the ROS-JNK-Bcl-2 signaling pathway. © 2017 Wiley Periodicals, Inc.

Nitric oxide signals ROS scavenger-mediated enhancement of PAL activity in nitrogen-deficient Matricaria chamomilla roots: side effects of scavengers.

PubMed

Kovácik, Jozef; Klejdus, Borivoj; Backor, Martin

2009-06-15

Owing to the abundance of phenolic metabolites in plant tissue, their accumulation represents an important tool for stress protection. However, the regulation of phenolic metabolism is still poorly known. The regulatory role of reactive oxygen species (ROS) in the activity of phenylalanine ammonia-lyase (PAL) in nitrogen (N)-deficient chamomile roots treated for 24 h was studied using three ROS scavengers [dithiothreitol (DTT), salicylhydroxamic acid, and sodium benzoate]. Scavengers decreased the level of hydrogen peroxide and/or superoxide (and up-regulated ascorbate/guaiacol peroxidase and glutathione reductase), but, surprisingly, stimulated PAL activity. This up-regulation was correlated with increases in nitric oxide (NO) content, total soluble phenols, selected phenolic acids, and, partially, lignin (being expressed the most in DTT-exposed roots). We therefore tested the hypothesis that NO may be involved in these changes. Application of 2-phenyl-4,4,5,5-tetramethylimidazoline-1-oxyl-3-oxide (PTIO) decreased PAL activity and the accumulation of soluble phenols in all treatments. Exogenous H(2)O(2) and NO also stimulated PAL activity and the accumulation of phenols. We conclude that NO, in addition to hydrogen peroxide, may regulate PAL activity during N deficiency. The anomalous effect of PTIO on NO content and possible mechanism of ROS scavenger-evoked NO increases in light of the current knowledge are also discussed.

Strain-Dependent Oxidant Release in Articular Cartilage Originates from Mitochondria

PubMed Central

J, Brouillette M; S, Ramakrishnan P; M, Wagner V; E, Sauter E; J, Journot B; O, McKinley T; A, Martin J

2013-01-01

Mechanical loading is essential for articular cartilage homeostasis and plays a central role in the cartilage pathology, yet the mechanotransduction processes that underlie these effects remain unclear. Previously we showed that lethal amounts of reactive oxygen species (ROS) were liberated from the mitochondria in response to mechanical insult, and that chondrocyte deformation may be a source of ROS. To this end, we hypothesized that mechanically-induced mitochondrial ROS is related to the magnitude of cartilage deformation. To test this, we measured axial tissue strains in cartilage explants subjected to semi-confined compressive stresses of 0, 0.05, 0.1, 0.25, 0.5, or 1.0 MPa. The presence of ROS was then determined by confocal imaging with dihydroethidium (DHE), an oxidant sensitive fluorescent probe. Our results indicated that ROS levels increased linearly relative to the magnitude of axial strains (r2 = 0.83, p < 0.05), and significant cell death was observed at strains > 40%. By contrast, hydrostatic stress, which causes minimal tissue strain, had no significant effect. Cell permeable superoxide dismutase mimetic Mn(III)tetrakis (1-methyl-4-pyridyl) porphyrin pentachloride (MnTMPyP) significantly decreased ROS levels at 0.5 and 0.25 MPa. Electron transport chain inhibitor, rotenone, and cytoskeletal inhibitor, cytochalasin B, significantly decreased ROS levels at 0.25 MPa. Our findings strongly suggest that ROS and mitochondrial oxidants contribute to cartilage mechanobiology. PMID:23896937

The Permeability Transition Pore Controls Cardiac Mitochondrial Maturation and Myocyte Differentiation

PubMed Central

Hom, Jennifer R.; Quintanilla, Rodrigo A.; Hoffman, David L.; Karen L., de Mesy Bentley; Molkentin, Jeffery D.; Sheu, Shey-Shing; Porter, George A.

2011-01-01

SUMMARY Although mature myocytes rely on mitochondria as the primary source of energy, the role of mitochondria in the developing heart is not well known. Here, we find closure of the mitochondrial permeability transition pore (mPTP) drives maturation of mitochondrial structure and function and myocyte differentiation. Cardiomyocytes at embryonic day (E) 9.5, when compared to E13.5, displayed fragmented mitochondria with few cristae, a less polarized mitochondrial membrane potential, higher reactive oxygen species (ROS) levels, and an open mPTP. Pharmacologic and genetic closing of the mPTP yielded maturation of mitochondrial structure and function, lowered ROS, and increased myocyte differentiation (measured by counting Z-bands). Furthermore, myocyte differentiation was inhibited and enhanced with oxidant and antioxidant treatment, respectively, suggesting that redox signaling pathways lie downstream of mitochondria to regulate cardiac myocyte differentiation. PMID:21920313

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 senescing leaves of the esl mutant. Conversely, OsNox1, OsNox3, and OsFR07 were not associated with ABA-induced O2- generation during leaf senescence. PMID:29309410

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 senescing leaves of the esl mutant. Conversely, OsNox1, OsNox3, and OsFR07 were not associated with ABA-induced O2- generation during leaf senescence.

Time-lapse microscopy of lung endothelial cells under hypoxia

NASA Astrophysics Data System (ADS)

Mehrvar, Shima; Ghanian, Zahra; Kondouri, Ganesh; Camara, Amadou S.; Ranji, Mahsa

2017-02-01

Objective: This study utilizes fluorescence microscopy to assess the effect of the oxygen tension on the production of reactive oxygen species (ROS) in mitochondria of fetal pulmonary artery endothelial cells (FPAECs). Introduction: Hypoxia is a severe oxygen stress, which mostly causes irreversible injury in lung cells. However, in some studies, it is reported that hypoxia decreases the severity of injuries. In this study, ROS production level was examined in hypoxic FPAECs treated with pentachlorophenol (PCP, uncoupler). This work was accomplished by monitoring and quantifying the changes in the level of the produced ROS in hypoxic cells before and after PCP treatment. Materials and methods: The dynamic of the mitochondrial ROS production in two groups of FPAECs was measured over time using time-lapse microscopy. For the first group, cells were incubated in 3% hypoxic condition for 2 hours and then continuously were exposed to hypoxic condition for imaging as well. For the second group, cells were incubated in normal oxygen condition. Time lapse images of the cells loaded with Mito-SOX (ROS indicator) were acquired, and the red fluorescence intensity profile of the cells was calculated. Changes in the level of the fluorescence intensity profile while they are treated with PCP indicates the dynamics of the ROS level. Results: The intensity profiles of the PCP-treated cells in the first group showed 47% lower ROS production rate than the PCP-treated cells in the second group. Conclusion: Time lapse microscopy revealed that hypoxic cells have lower ROS generation while treated with PCP. Therefore, this result suggests that hypoxia decreased electron transport chain activity in uncoupled chain.

The path from mitochondrial ROS to aging runs through the mitochondrial permeability transition pore.

PubMed

Rottenberg, Hagai; Hoek, Jan B

2017-10-01

Excessive production of mitochondrial reactive oxygen species (mROS) is strongly associated with mitochondrial and cellular oxidative damage, aging, and degenerative diseases. However, mROS also induces pathways of protection of mitochondria that slow aging, inhibit cell death, and increase lifespan. Recent studies show that the activation of the mitochondrial permeability transition pore (mPTP), which is triggered by mROS and mitochondrial calcium overloading, is enhanced in aged animals and humans and in aging-related degenerative diseases. mPTP opening initiates further production and release of mROS that damage both mitochondrial and nuclear DNA, proteins, and phospholipids, and also releases matrix NAD that is hydrolyzed in the intermembrane space, thus contributing to the depletion of cellular NAD that accelerates aging. Oxidative damage to calcium transporters leads to calcium overload and more frequent opening of mPTP. Because aging enhances the opening of the mPTP and mPTP opening accelerates aging, we suggest that mPTP opening drives the progression of aging. Activation of the mPTP is regulated, directly and indirectly, not only by the mitochondrial protection pathways that are induced by mROS, but also by pro-apoptotic signals that are induced by DNA damage. We suggest that the integration of these contrasting signals by the mPTP largely determines the rate of cell aging and the initiation of cell death, and thus animal lifespan. The suggestion that the control of mPTP activation is critical for the progression of aging can explain the conflicting and confusing evidence regarding the beneficial and deleterious effects of mROS on health and lifespan. © 2017 The Authors. Aging Cell published by the Anatomical Society and John Wiley & Sons Ltd.

Curcuminoid EF24 enhances the anti‐tumour activity of Akt inhibitor MK‐2206 through ROS‐mediated endoplasmic reticulum stress and mitochondrial dysfunction in gastric cancer

PubMed Central

Chen, Xi; Dai, Xuanxuan; Zou, Peng; Chen, Weiqian; Rajamanickam, Vinothkumar; Feng, Chen; Zhuge, Weishan; Qiu, Chenyu; Ye, Qingqing

2017-01-01

Background and Purpose Gastric cancer is one of the leading causes of morbidity and mortality worldwide. Akt is an anti‐apoptotic kinase that plays a dynamic role in cell survival and is implicated in the pathogenesis of gastric cancer. MK‐2206, the first allosteric inhibitor of Akt, is in clinical trials for a number of cancers. Although preclinical studies showed promise, clinical trials reported it had no effect when given alone at tolerated doses. The aim of our study was to delineate the effects of MK‐2206 on gastric cancer cells and explore the ability of combination treatments to enhance the anti‐tumour activity of MK‐2206. Experimental Approach SGC‐7901, BGC‐823 cells and immunodeficient mice were chosen as a model to study the treatment effects. Changes in cell viability, apoptosis and ROS, endoplasmic reticulum stress and mitochondrial dysfunction in the cells were analysed by MTT assays, ROS imaging and FACSCalibur, electron microscopy, JC‐1 staining and western blotting. Key Results MK‐2206 induced apoptotic cell death through the generation of ROS. We utilized ROS production to target gastric cancer cells by combining MK‐2206 and an ROS inducer EF24. Our in vitro and in vivo xenograft studies showed that combined treatment with MK‐2206 and EF24 synergistically induced apoptosis in gastric cancer cells and caused cell cycle arrest. These activities were mediated through ROS generation and the induction of endoplasmic reticulum stress and mitochondrial dysfunction. Conclusion and Implications Targeting ROS generation by using a combination of an Akt inhibitor and EF24 could have potential as a therapy for gastric cancer. PMID:28255993

Curcumin analog EF24 induces apoptosis via ROS-dependent mitochondrial dysfunction in human colorectal cancer cells.

PubMed

He, Guodong; Feng, Chen; Vinothkumar, Rajamanickam; Chen, Weiqian; Dai, Xuanxuan; Chen, Xi; Ye, Qingqing; Qiu, Chenyu; Zhou, Huiping; Wang, Yi; Liang, Guang; Xie, Yubo; Wu, Wei

2016-12-01

Colorectal cancer is the most commonly diagnosed malignancy with high mortality rates worldwide. Improved therapeutic strategies with minimal adverse side effects are urgently needed. In this study, the anti-tumor effects of EF24, a novel analog of the natural compound curcumin, were evaluated in colorectal cancer cells. The anti-tumor activity of EF24 on human colon cancer lines (HCT-116, SW-620, and HT-29) was determined by measures of cell cycle arrest, apoptosis, and mitochondrial function. The contribution of ROS in the EF24-induced anti-tumor activity was evaluated by measures of H 2 O 2 and pretreatment with an ROS scavenger, NAC. The findings indicated that EF24 treatment dose-dependently inhibited cell viability and caused cell cycle arrest at G2/M phase in all the tested colon cancer cell lines. Furthermore, we demonstrated that EF24 treatment induced apoptosis effectively via enhancing intracellular accumulation of ROS in both HCT-116 and SW-620 cells, but with moderate effects in HT-29 cells. We found that EF24 treatment decreased the mitochondrial membrane potential in the colon cancer cells, leading to the release of mitochondrial cytochrome c. Also, EF24 induced activation of caspases 9 and 3, causing decreased Bcl-2 protein expression and Bcl-2/Bax ratio. Pretreatment with NAC, a ROS scavenger, abrogated the EF24-induced cell death, apoptosis, cell cycle arrest, and mitochondrial dysfunction, suggesting an upstream ROS generation which was responsible for the anticancer effects of EF24. Our findings support an anticancer mechanism by which EF24 enhanced ROS accumulation in colon cancer cells, thereby resulting in mitochondrial membrane collapse and activated intrinsic apoptotic signaling. Thus, EF24 could be a potential candidate for therapeutic application of colon cancer.

ROS and calcium signaling mediated pathways involved in stress responses of the marine microalgae Dunaliella salina to enhanced UV-B radiation.

PubMed

Zhang, Xinxin; Tang, Xuexi; Wang, Ming; Zhang, Wei; Zhou, Bin; Wang, You

2017-08-01

UV-B ray has been addressed to trigger common metabolic responses on marine microalgae, however, the upstream events responsible for these changes in marine microalgae are poorly understood. In the present study, a species of marine green microalgae Dunaliella salina was exposed to a series of enhanced UV-B radiation ranging from 0.25 to 1.00 KJ·m -2 per day. The role of ROS and calcium signaling in the D. salina responses to UV-B was discussed. Results showed that enhanced UV-B radiation markedly decreased the cell density in a dose-dependent manner, but the contents of protein and glycerol that were essential for cell growth increased. It suggested that it was cell division instead of cell growth that UV-B exerted negative effects on. The subcellular damages on nuclei and plasmalemma further evidenced the hypothesis. The nutrient absorption was affected with UV-B exposure, and the inhibition on PO 4 3- uptake was more serious compared to NO 3 - uptake. UV-B radiation promoted reactive oxygen species (ROS) formation and thiobarbituric acid reactive substances (TBARS) contents, decreased the redox status and altered the antioxidant enzyme activities. The addition of the ROS scavenger and the glutathione biosynthesis precursor N-acetyl-l-cysteine (NAC) alleviated the stress degree, implying ROS-mediated pathway was involved in the stress response to UV-B radiation. Transient increase in Ca 2+ -ATPase was triggered simultaneously with UV-B exposure. Meanwhile, the addition of an intracellular free calcium chelator aggravated the damage of cell division, but exogenous calcium and ion channel blocker applications did not, inferring that endogenously initiated calcium signaling played roles in response to UV-B. Cross-talk analysis showed a relatively clear relationship between ROS inhibition and Ca 2+ -ATPase suppression, and a relation between Ca 2+ inhibition and GPx activity change was also observed. It was thus presumed that ROS-coupled calcium signaling via the glutathione cycle was involved in the response of marine microalgae to UV-B stimuli. Copyright © 2017 Elsevier B.V. All rights reserved.

SREBP-1c overactivates ROS-mediated hepatic NF-κB inflammatory pathway in dairy cows with fatty liver.

PubMed

Li, Xinwei; Huang, Weikun; Gu, Jingmin; Du, Xiliang; Lei, Lin; Yuan, Xue; Sun, Guoquan; Wang, Zhe; Li, Xiaobing; Liu, Guowen

2015-10-01

Dairy cows with fatty liver are characterized by hepatic lipid accumulation and a severe inflammatory response. Sterol receptor element binding protein-1c (SREBP-1c) and nuclear factor κB (NF-κB) are components of the main pathways for controlling triglyceride (TG) accumulation and inflammatory levels, respectively. A previous study demonstrated that hepatic inflammatory levels are positively correlated with hepatic TG content. We therefore speculated that SREBP-1c might play an important role in the overactivation of the hepatic NF-κB inflammatory pathway in cows with fatty liver. Compared with healthy cows, cows with fatty liver exhibited severe hepatic injury and high blood concentrations of the inflammatory cytokines TNF-α, IL-6 and IL-1β. Hepatic SREBP-1c-mediated lipid synthesis and the NF-κB inflammatory pathway were both overinduced in cows with fatty liver. In vitro, treatment with non-esterified fatty acids (NEFA) further increased SREBP-1c expression and NF-κB pathway activation, which then promoted TG and inflammatory cytokine synthesis. SREBP-1c overexpression overactivated the NF-κB inflammatory pathway in hepatocytes by increasing ROS content and not through TLR4. Furthermore, SREBP-1c silencing decreased ROS content and further attenuated the activation of the NEFA-induced NF-κB pathway, thereby decreasing TNF-α, IL-6 and IL-1β synthesis. SREBP-1c-overexpressing mice exhibited hepatic steatosis and an overinduced hepatic NF-κB pathway. Taken together, these results indicate that SREBP-1c enhances the NEFA-induced overactivation of the NF-κB inflammatory pathway by increasing ROS in cow hepatocytes, thereby further increasing hepatic inflammatory injury in cows with fatty liver. Copyright © 2015. Published by Elsevier Inc.

Mutagenic effect of freezing on nuclear DNA of Saccharomyces cerevisiae.

PubMed

Todorova, T; Pesheva, M; Stamenova, R; Dimitrov, M; Venkov, P

2012-05-01

Although fragmentation of DNA has been observed in cells undergoing freezing procedures, a mutagenic effect of sub-zero temperature treatment has not been proved by induction and isolation of mutants in nuclear DNA (nDNA). In this communication we supply evidence for mutagenicity of freezing on nDNA of Saccharomyces cerevisiae cells. In the absence of cryoprotectors, cooling for 2 h at +4°C and freezing for 1 h at -10°C and 16 h at -20°C, with a cooling rate of 3°C/min, resulted in induction of frame-shift and reverse mutations in microsatellite and coding regions of nDNA. The sub-zero temperature exposure also has a strong recombinogenic effect, evidenced by induction of gene-conversion and crossing-over events. Freezing induces mutations and enhances recombination with a frequency equal to or higher than that of methylmethanesulphonate at comparable survival rates. The signals for the appearance of nDNA lesions induced by freezing are detected and transduced by the DNA damage pathway. Extracellular cryoprotectors did not prevent the mutagenic effect of freezing, while accumulation of trehalose inside cells reduced nDNA cryodamage. Freezing of cells is accompanied by generation of high ROS levels, and the oxidative stress raised during the freeze-thaw process is the most likely reason for the DNA damaging effect. Experiments with mitochondrial rho⁻ mutants or scavengers of ROS indicated that mutagenic and recombinogenic effects of sub-zero temperatures can be decreased but not eliminated by reduction of ROS level. The complete protection against cryodamage in nDNA required simultaneous usage of intracellular cryoprotector and ROS scavenger during the freeze-thaw process. Copyright © 2012 John Wiley & Sons, Ltd.

Effect of Mucuna pruriens on oxidative stress mediated damage in aged rat sperm.

PubMed

Suresh, Sekar; Prithiviraj, Elumalai; Prakash, Seppan

2010-02-01

Mucuna pruriens Linn., a leguminous plant, has been recognized as an aphrodisiac and spermatogenic agent. Protective efficacy of M. pruriens on reactive oxygen species (ROS)-induced pathophysiological alterations in structural and functional integrity of epididymal sperm in aged Wister albino rat was analysed. Animals were grouped as groups I, II, III and IV, i.e. young (control), aged, aged treated with ethanolic extract (200 mg/kg b.w.) of M. pruriens and young rats treated with M. pruriens, respectively. At the end of the experimental period, i.e. after 60 days animals were sacrificed, epididymal sperm were collected and subjected to count, viability, motility, morphology and morphometric analysis. Enzymatic and non-enzymatic antioxidants, ROS, lipid peroxidation (LPO), DNA damage, chromosomal integrity and mitochondrial membrane potential were estimated. Results obtained from the aged animals showed significant reduction in sperm count, viability and motility, increased morphological damage and an increase in the number of sperm with cytoplasmic remnant, and these alterations were significantly reversed in M. pruriens treated group. Significant increase in LPO, HO and H(2)O(2) production and significant decline in the levels of the enzymatic and non-enzymatic antioxidants were observed in the aged animals. Supplementation of M. pruriens significantly reduced ROS and LPO production and significant increase in both enzymatic and non-enzymatic antioxidant levels. There were significant DNA damage, loss of chromosomal integrity and increase in mitochondrial membrane permeability in aged rat sperm. This was significantly reduced in group III. Present observation indicates the antioxidant enhancing property, free radical quenching ability and spermatogenic efficacy of the M. pruriens. Collectively, sperm damage in ageing was significantly reduced by quenching ROS, improving antioxidant defence system and mitochondrial function.

SNF1-Related Protein Kinases Type 2 Are Involved in Plant Responses to Cadmium Stress1[C][W

PubMed Central

Kulik, Anna; Anielska-Mazur, Anna; Bucholc, Maria; Koen, Emmanuel; Szymańska, Katarzyna; Żmieńko, Agnieszka; Krzywińska, Ewa; Wawer, Izabela; McLoughlin, Fionn; Ruszkowski, Dariusz; Figlerowicz, Marek; Testerink, Christa; Skłodowska, Aleksandra; Wendehenne, David; Dobrowolska, Grażyna

2012-01-01

Cadmium ions are notorious environmental pollutants. To adapt to cadmium-induced deleterious effects plants have developed sophisticated defense mechanisms. However, the signaling pathways underlying the plant response to cadmium are still elusive. Our data demonstrate that SnRK2s (for SNF1-related protein kinase2) are transiently activated during cadmium exposure and are involved in the regulation of plant response to this stress. Analysis of tobacco (Nicotiana tabacum) Osmotic Stress-Activated Protein Kinase activity in tobacco Bright Yellow 2 cells indicates that reactive oxygen species (ROS) and nitric oxide, produced mainly via an l-arginine-dependent process, contribute to the kinase activation in response to cadmium. SnRK2.4 is the closest homolog of tobacco Osmotic Stress-Activated Protein Kinase in Arabidopsis (Arabidopsis thaliana). Comparative analysis of seedling growth of snrk2.4 knockout mutants versus wild-type Arabidopsis suggests that SnRK2.4 is involved in the inhibition of root growth triggered by cadmium; the mutants were more tolerant to the stress. Measurements of the level of three major species of phytochelatins (PCs) in roots of plants exposed to Cd2+ showed a similar (PC2, PC4) or lower (PC3) concentration in snrk2.4 mutants in comparison to wild-type plants. These results indicate that the enhanced tolerance of the mutants does not result from a difference in the PCs level. Additionally, we have analyzed ROS accumulation in roots subjected to Cd2+ treatment. Our data show significantly lower Cd2+-induced ROS accumulation in the mutants’ roots. Concluding, the obtained results indicate that SnRK2s play a role in the regulation of plant tolerance to cadmium, most probably by controlling ROS accumulation triggered by cadmium ions. PMID:22885934

Decreasing mitochondrial fission diminishes vascular smooth muscle cell migration and ameliorates intimal hyperplasia

PubMed Central

Wang, Li; Yu, Tianzheng; Lee, Hakjoo; O'Brien, Dawn K.; Sesaki, Hiromi; Yoon, Yisang

2015-01-01

Aims Vascular smooth muscle cell (VSMC) migration in response to arterial wall injury is a critical process in the development of intimal hyperplasia. Cell migration is an energy-demanding process that is predicted to require mitochondrial function. Mitochondria are morphologically dynamic, undergoing continuous shape change through fission and fusion. However, the role of mitochondrial morphology in VSMC migration is not well understood. The aim of the study is to understand how mitochondrial fission contributes to VSMC migration and provides its in vivo relevance in the mouse model of intimal hyperplasia. Methods and results In primary mouse VSMCs, the chemoattractant PDGF induced mitochondrial shortening through the mitochondrial fission protein dynamin-like protein 1 (DLP1)/Drp1. Perturbation of mitochondrial fission by expressing the dominant-negative mutant DLP1-K38A or by DLP1 silencing greatly decreased PDGF-induced lamellipodia formation and VSMC migration, indicating that mitochondrial fission is an important process in VSMC migration. PDGF induced an augmentation of mitochondrial energetics as well as ROS production, both of which were found to be necessary for VSMC migration. Mechanistically, the inhibition of mitochondrial fission induced an increase of mitochondrial inner membrane proton leak in VSMCs, abrogating the PDGF-induced energetic enhancement and an ROS increase. In an in vivo model of intimal hyperplasia, transgenic mice expressing DLP1-K38A displayed markedly reduced ROS levels and neointima formation in response to femoral artery wire injury. Conclusions Mitochondrial fission is an integral process in cell migration, and controlling mitochondrial fission can limit VSMC migration and the pathological intimal hyperplasia by altering mitochondrial energetics and ROS levels. PMID:25587046

Copper(II) oxide nanoparticles augment antifilarial activity of Albendazole: In vitro synergistic apoptotic impact against filarial parasite Setaria cervi.

PubMed

Zafar, Atif; Ahmad, Irshad; Ahmad, Ajaz; Ahmad, Masood

2016-03-30

Mass treatment of lymphatic filariasis with Albendazole (ABZ), a therapeutic benzimidazole, is fraught with serious limitations such as possible drug resistance and poor macrofilaricidal activity. Therefore, we need to develop new ABZ-based formulations to improve its antifilarial effectiveness. CuO nanoparticles were used as an adjuvant with ABZ to form ABZ-CuO nanocomposite, which was characterized by UV-vis spectroscopy, FT-IR, AFM and SEM. Antifilarial activity of nanocomposite was evaluated using relative motility assay and dye exclusion test in dark and under UV light. ROS generation, antioxidant levels, lipid peroxidation and DNA fragmentation in nanocomposite treated parasites were estimated. Biophysical techniques were employed to ascertain the mode of binding of nanocomposite to parasitic DNA. Nanocomposite increases parasite mortality as compared to ABZ in dark, and its antifilarial effect was increased further under UV light. Elevated ROS production and decline of parasitic-GST and GSH levels were observed in nanocomposite treated worms in dark, and these effects were pronounced further under UV light. Nanocomposite leads to higher DNA fragmentation as compared to ABZ alone. Further, we found that nanocomposite binds parasitic DNA in an intercalative manner where it generates ROS to induce DNA damage. Thus, oxidative stress production due to ROS generation and consequent DNA fragmentation leads to apoptosis in worms. This is the first report supporting CuO nanoparticles as a potential adjuvant with ABZ against filariasis along with enhanced antifilarial activity of nanocomposite under UV light. These findings, thus, indicate that development of ABZ-loaded nanoparticle compounds may serve as promising leads for filariasis treatment. Copyright © 2016 Elsevier B.V. All rights reserved.

Thymoquinone Inhibits Tumor Growth and Induces Apoptosis in a Breast Cancer Xenograft Mouse Model: The Role of p38 MAPK and ROS

PubMed Central

Woo, Chern Chiuh; Hsu, Annie; Kumar, Alan Prem; Sethi, Gautam; Tan, Kwong Huat Benny

2013-01-01

Due to narrow therapeutic window of cancer therapeutic agents and the development of resistance against these agents, there is a need to discover novel agents to treat breast cancer. The antitumor activities of thymoquinone (TQ), a compound isolated from Nigella sativa oil, were investigated in breast carcinoma in vitro and in vivo. Cell responses after TQ treatment were assessed by using different assays including MTT assay, annexin V-propidium iodide staining, Mitosox staining and Western blot. The antitumor effect was studied by breast tumor xenograft mouse model, and the tumor tissues were examined by histology and immunohistochemistry. The level of anti-oxidant enzymes/molecules in mouse liver tissues was measured by commercial kits. Here, we show that TQ induced p38 phosphorylation and ROS production in breast cancer cells. These inductions were found to be responsible for TQ’s anti-proliferative and pro-apoptotic effects. Moreover, TQ-induced ROS production regulated p38 phosphorylation but not vice versa. TQ treatment was found to suppress the tumor growth and this effect was further enhanced by combination with doxorubicin. TQ also inhibited the protein expression of anti-apoptotic genes, such as XIAP, survivin, Bcl-xL and Bcl-2, in breast cancer cells and breast tumor xenograft. Reduced Ki67 and increased TUNEL staining were observed in TQ-treated tumors. TQ was also found to increase the level of catalase, superoxide dismutase and glutathione in mouse liver tissues. Overall, our results demonstrated that the anti-proliferative and pro-apoptotic effects of TQ in breast cancer are mediated through p38 phosphorylation via ROS generation. PMID:24098377

Docosahexaenoic acid attenuates oxidative stress and protects human gingival fibroblasts against cytotoxicity induced by hydrogen peroxide and butyric acid.

PubMed

Zgorzynska, Emilia; Wierzbicka-Ferszt, Anita; Dziedzic, Barbara; Witusik-Perkowska, Monika; Zwolinska, Anna; Janas, Anna; Walczewska, Anna

2015-01-01

The oxidative burst of the host cells associated with bacterial pathogen infection contributes to the destruction of periodontal tissue. The present study investigates the effect of docosahexaenoic acid (DHA) on human gingival fibroblast (HGF) viability and ROS generation. The cell viability by MTT assay, ROS level using H2DCF-DA probe, and protein thiol content were measured in HGFs after 24h preincubation with different concentrations of DHA followed by treatment with H2O2. The cell death rate was determined by Annexin V/propidium iodide staining, and mitochondrial membrane potential (ΔΨm) was examined by MitoTracker Red probe in H2O2- and butyric acid-treated HGFs. The fatty acid composition of plasma membranes after incubation with DHA was determined by gas chromatography mass spectrometry. DHA preincubation in a dose-dependent manner increased the viability of HGFs exposed to H2O2 and decreased ROS generation compared to the control cells. In HGFs preincubated with 30μM DHA, the ΔΨm significantly increased in both H2O2- and butyric acid-treated cells. Moreover, incubation with DHA preserved the protein thiol level as effectively as N-acetylcysteine. Application of 50μM DHA increased the quantity of viable cells, decreased the number of necrotic cells after H2O2 treatment, and protected HGFs from apoptosis induced by butyric acid. DHA in the plasma membranes of these HGFs represented about 6% of the total amount of fatty acids. These results demonstrate that enrichment of HGFs with DHA reduces ROS generation and enhances the mitochondrial membrane potential protecting the fibroblasts against cytotoxic factors. Copyright © 2014 Elsevier Ltd. All rights reserved.

Effects of irradiation distance on supply of reactive oxygen species to the bottom of a Petri dish filled with liquid by an atmospheric O{sub 2}/He plasma jet

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

Kawasaki, Toshiyuki, E-mail: kawasaki@nbu.ac.jp; Kusumegi, Shota; Kudo, Akihiro

The impact of irradiation distances on plasma jet-induced specific effects on the supply of reactive oxygen species (ROS) to the bottom of a Petri dish filled with liquid was investigated using a KI-starch gel reagent that can be employed as a ROS indicator even in water. O{sub 3} exposure experiments without plasma irradiation were also performed to elucidate the specific effects of the plasma jet. Relative concentrations of ROS transported to the bottom were evaluated using absorbance measurements. The results indicated that ROS supply to the bottom is markedly enhanced by the plasma jet irradiation at shorter irradiation distances, whereasmore » similar results could not be obtained for the O{sub 3} exposure. In these cases, the liquid mixing in the depth direction was also enhanced by the plasma jet irradiation only, and the supply of reactive atomic oxygen to the liquid surface was markedly increased as well.« less

The antioxidant potential of alprazolam on the redox status of peripheral blood leukocytes in restraint-stressed mice.

PubMed

Núñez, María J; Novío, Silvia; Amigo, Gonzalo; Freire-Garabal, Manuel

2011-10-24

Stress can cause adverse reactions in the body that induce a wide range of biochemical and behavioral changes. Oxidative damage is an established outcome of stress that has been implicated in the pathogenesis of mood and anxiety disorders. Anxiolytic drugs are widely prescribed to treat these conditions; however, no animal study has investigated the effect of benzodiazepines on the levels of intracellular reactive oxygen species (ROS) in the peripheral blood leukocytes of stressed mice. Mice were immobilized for a period of 6h. Alprazolam (0.1-0.8 mg/kg of body weight) was administered 30 min before subjecting the animals to acute stress. The level of intracellular ROS in lymphocytes, granulocytes, and monocytes in the peripheral blood of stressed mice was investigated by using a 2',7'-dichlorofluorescein diacetate (DCFH-DA) probe. Our results show that restraint stress significantly increases the generation of ROS in peripheral defense cells. Treatment with alprazolam partially reverses the adverse effects of stress. Our findings suggest that the therapeutic efficacy of alprazolam may be mediated, at least partially, by the reversal of oxidative damage as demonstrated by the protective enhancement of antioxidant status following a stress-induced decline. Because alprazolam is used for the treatment of anxiety in patients with cancer, neurodegenerative disease, inflammatory bowel diseases, and other diseases, these results may have important clinical implications. Copyright © 2011 Elsevier Inc. All rights reserved.

The regulation of vascular endothelial growth factor-induced microvascular permeability requires Rac and reactive oxygen species.

PubMed

Monaghan-Benson, Elizabeth; Burridge, Keith

2009-09-18

Vascular permeability is a complex process involving the coordinated regulation of multiple signaling pathways in the endothelial cell. It has long been documented that vascular endothelial growth factor (VEGF) greatly enhances microvascular permeability; however, the molecular mechanisms controlling VEGF-induced permeability remain unknown. Treatment of microvascular endothelial cells with VEGF led to an increase in reactive oxygen species (ROS) production. ROS are required for VEGF-induced permeability as treatment with the free radical scavenger, N-acetylcysteine, inhibited this effect. Additionally, treatment with VEGF caused ROS-dependent tyrosine phosphorylation of both vascular-endothelial (VE)-cadherin and beta-catenin. Rac1 was required for the VEGF-induced increase in permeability and adherens junction protein phosphorylation. Knockdown of Rac1 inhibited VEGF-induced ROS production consistent with Rac lying upstream of ROS in this pathway. Collectively, these data suggest that VEGF leads to a Rac-mediated generation of ROS, which, in turn, elevates the tyrosine phosphorylation of VE-cadherin and beta-catenin, ultimately regulating adherens junction integrity.

Expression of GRIM-19 in unexplained recurrent spontaneous abortion and possible pathogenesis.

PubMed

Yang, Yang; Cheng, Laiyang; Deng, Xiaohui; Yu, Hongling; Chao, Lan

2018-05-08

Is aberrant expression of gene associated with retinoid-interferon-induced mortality-19 (GRIM-19) associated with unexplained recurrent spontaneous abortion (URSA)? GRIM-19 deficiency may regulate regulatory T cell/ T helper 17 cell (Treg/Th17) balance partly through reactive oxygen species (ROS) - mammalian target of rapamycin (mTOR) signaling axis in URSA. Immunological disorders may cause impaired maternal immune tolerance to the fetus and result in fetal rejection. The differentiation of Treg and Th17 cells is controlled by phosphoinositide 3-kinase (PI3K)/Akt/mTOR signaling pathway. GRIM-19 participates in the immune response, but its role in URSA is largely unknown. The current study included 28 URSA patients and 30 non-pregnant healthy women. The proportion of Treg and Th17 cells in peripheral blood of URSA patients and control subjects were assessed with flow cytometry. The expression of GRIM-19 in peripheral blood lymphocytes (PBLs) was measured with quantitative real-time PCR and western blot analysis. Furthermore, the ROS level in the PBLs of URSA patients and control subjects were assessed by 2'-7'-dichlorodihydrofluorescein diacetate (DCFH-DA) staining. Then, Akt/mTOR expression in the PBLs was measured. Downregulation of GRIM-19 in Jurkat cells was performed by specific small interfering RNA (siRNA). Then, intracellular ROS production and the expression of p-mTOR, which is known to enhance Th17 differentiation and decrease Treg cell differentiation, were detected. Finally, N-acetylcysteine (NAC) was used to decrease the intracellular ROS level, and the expression of p-mTOR was measured. The proportion of Treg cells was reduced in URSA patients, whereas the proportion of Th17 cells was increased. The expression of GRIM-19 was significantly lower in PBLs of URSA patients. Furthermore, there is a considerable increase in intracellular ROS production and a high level of p-Akt and p-mTOR expression in the PBLs of URSA patients compared with the control subjects. In parallel to this, downregulation of GRIM-19 in the Jurkat cells by siRNA results in an increased ROS production and an increased expression of p-mTOR. Importantly, the upregulation of p-mTOR resulting from GRIM-19 loss was significantly reversed in the cells treatment with ROS inhibitor N-acetyl-L-cysteine (NAC), indicating that ROS was indeed required for GRIM-19 depletion induced p-mTOR expression. None. A large number of researches have confirmed that the differentiation of Treg and Th17 cells is controlled by PI3K/Akt/mTOR signaling pathway. We have not shown the regulatory role of ROS and PI3K/Akt/mTOR in Treg and Th17 differentiation in this study. Our study has demonstrated that GRIM-19 deficiency may play a role in regulating Treg/Th17 balance partly through ROS - mTOR signaling axis in URSA. The present study offers a new perspective to the roles of GRIM-19 in immunoregulation. This work was supported by the National Natural Science Foundation of China (grant numbers 81571511, 81701528, 81370711 and 30901603), the Shandong Provincial Natural Science Foundation (grant number ZR2017PH052 and ZR2013HM090) and the Science Foundation of Qilu Hospital of Shandong University, Fundamental Research Funds of Shandong University (grant numbers 2015QLQN50 and 2015QLMS24). The authors declare that there is no conflict of interest that could prejudice the impartiality of the present research.

Enhanced transfection by antioxidative polymeric gene carrier that reduces polyplex-mediated cellular oxidative stress.

PubMed

Lee, Min Sang; Kim, Nak Won; Lee, Kyuri; Kim, Hongtae; Jeong, Ji Hoon

2013-06-01

To test the hypothesis in which polyplex-induced oxidative stress may affect overall transfection efficiency, an antioxidative transfection system minimizing cellular oxidative stress was designed for enhanced transfection. An amphiphilic copolymer (PEI-PLGA) was synthesized and used as a micelle-type gene carrier containing hydrophobic antioxidant, α-tocopherol. Cellular oxidative stress and the change of mitochondrial membrane potential after transfection was measured by using a fluorescent probe (H₂DCFDA) and lipophilic cationic probe (JC-1), respectively. Transfection efficiency was determined by measuring a reporter gene (luciferase) expression level. The initial transfection study with conventional PEI/plasmid DNA polyplex showed significant generation of reactive oxygen species (ROS). The PEI-PLGA copolymer successfully carried out the simultaneous delivery of α-tocopherol and plasmid DNA (PEI-PLGA/Toco/pDNA polyplex) into cells, resulting in a significant reduction in cellular ROS generation after transfection and helped to maintain the mitochondrial membrane potential (ΔΨ). In addition, the transfection efficiency was dramatically increased using the antioxidative transfection system. This work showed that oxidative stress would be one of the important factors that should be considered in designing non-viral gene carriers and suggested a possible way to reduce the carrier-mediated oxidative stress, which consequently leads to enhanced transfection.

Live Candida albicans suppresses production of reactive oxygen species in phagocytes.

PubMed

Wellington, Melanie; Dolan, Kristy; Krysan, Damian J

2009-01-01

Production of reactive oxygen species (ROS) is an important aspect of phagocyte-mediated host responses. Since phagocytes play a crucial role in the host response to Candida albicans, we examined the ability of Candida to modulate phagocyte ROS production. ROS production was measured in the murine macrophage cell line J774 and in primary phagocytes using luminol-enhanced chemiluminescence. J774 cells, murine polymorphonuclear leukocytes (PMN), human monocytes, and human PMN treated with live C. albicans produced significantly less ROS than phagocytes treated with heat-killed C. albicans. Live C. albicans also suppressed ROS production in murine bone marrow-derived macrophages from C57BL/6 mice, but not from BALB/c mice. Live C. albicans also suppressed ROS in response to external stimuli. C. albicans and Candida glabrata suppressed ROS production by phagocytes, whereas Saccharomyces cerevisiae stimulated ROS production. The cell wall is the initial point of contact between Candida and phagocytes, but isolated cell walls from both heat-killed and live C. albicans stimulated ROS production. Heat-killed C. albicans has increased surface exposure of 1,3-beta-glucan, a cell wall component that can stimulate phagocytes. To determine whether surface 1,3-beta-glucan exposure accounted for the difference in ROS production, live C. albicans cells were treated with a sublethal dose of caspofungin to increase surface 1,3-beta-glucan exposure. Caspofungin-treated C. albicans was fully able to suppress ROS production, indicating that suppression of ROS overrides stimulatory signals from 1,3-beta-glucan. These studies indicate that live C. albicans actively suppresses ROS production in phagocytes in vitro, which may represent an important immune evasion mechanism.

Live Candida albicans Suppresses Production of Reactive Oxygen Species in Phagocytes▿ †

PubMed Central

Wellington, Melanie; Dolan, Kristy; Krysan, Damian J.

2009-01-01

Production of reactive oxygen species (ROS) is an important aspect of phagocyte-mediated host responses. Since phagocytes play a crucial role in the host response to Candida albicans, we examined the ability of Candida to modulate phagocyte ROS production. ROS production was measured in the murine macrophage cell line J774 and in primary phagocytes using luminol-enhanced chemiluminescence. J774 cells, murine polymorphonuclear leukocytes (PMN), human monocytes, and human PMN treated with live C. albicans produced significantly less ROS than phagocytes treated with heat-killed C. albicans. Live C. albicans also suppressed ROS production in murine bone marrow-derived macrophages from C57BL/6 mice, but not from BALB/c mice. Live C. albicans also suppressed ROS in response to external stimuli. C. albicans and Candida glabrata suppressed ROS production by phagocytes, whereas Saccharomyces cerevisiae stimulated ROS production. The cell wall is the initial point of contact between Candida and phagocytes, but isolated cell walls from both heat-killed and live C. albicans stimulated ROS production. Heat-killed C. albicans has increased surface exposure of 1,3-β-glucan, a cell wall component that can stimulate phagocytes. To determine whether surface 1,3-β-glucan exposure accounted for the difference in ROS production, live C. albicans cells were treated with a sublethal dose of caspofungin to increase surface 1,3-β-glucan exposure. Caspofungin-treated C. albicans was fully able to suppress ROS production, indicating that suppression of ROS overrides stimulatory signals from 1,3-β-glucan. These studies indicate that live C. albicans actively suppresses ROS production in phagocytes in vitro, which may represent an important immune evasion mechanism. PMID:18981256

High level of reduced glutathione contributes to detoxification of lipid peroxide-derived reactive carbonyl species in transgenic Arabidopsis overexpressing glutathione reductase under aluminum stress.

PubMed

Yin, Lina; Mano, Jun'ichi; Tanaka, Kiyoshi; Wang, Shiwen; Zhang, Meijuan; Deng, Xiping; Zhang, Suiqi

2017-10-01

Lipid peroxide-derived reactive carbonyl species (RCS), generated downstream of reactive oxygen species (ROS), are critical damage-inducing species in plant aluminum (Al) toxicity. In mammals, RCS are scavenged primarily by glutathione (reduced form of glutathione, GSH), but in plant Al stress, contribution of GSH to RCS detoxification has not been evaluated. In this study, Arabidopsis plants overexpressing the gene AtGR1 (accession code At3g24170), encoding glutathione reductase (GR), were generated, and their performance under Al stress was examined. These transgenic plants (GR-OE plants) showed higher GSH levels and GSH/GSSG (oxidized form of GSH) ratio, and an improved Al tolerance as they suffered less inhibition of root growth than wild-type under Al stress. Exogenous application of 4-hydroxy-2-nonenal, an RCS responsible for Al toxicity in roots, markedly inhibited root growth in wild-type plants. GR-OE plants suffered significantly smaller inhibition, indicating that the enhanced GSH level increased the capacity of RCS detoxification. The generation of H 2 O 2 due to Al stress in GR-OE plants was lower by 26% than in wild-type. Levels of various RCS, such as malondialdehyde, butyraldehyde, phenylacetaldehyde, (E)-2-heptenal and n-octanal, were suppressed by more than 50%. These results indicate that high levels of GSH and GSH/GSSG ratio by GR overexpression contributed to the suppression of not only ROS, but also RCS. Thus, the maintenance of GSH level by overexpressing GR reinforces dual detoxification functions in plants and is an efficient approach to enhance Al tolerance. © 2017 Scandinavian Plant Physiology Society.

ROS regulation of axonal mitochondrial transport is mediated by Ca2+ and JNK in Drosophila

PubMed Central

Liao, Pin-Chao; Tandarich, Lauren C.

2017-01-01

Mitochondria perform critical functions including aerobic ATP production and calcium (Ca2+) homeostasis, but are also a major source of reactive oxygen species (ROS) production. To maintain cellular function and survival in neurons, mitochondria are transported along axons, and accumulate in regions with high demand for their functions. Oxidative stress and abnormal mitochondrial axonal transport are associated with neurodegenerative disorders. However, we know little about the connection between these two. Using the Drosophila third instar larval nervous system as the in vivo model, we found that ROS inhibited mitochondrial axonal transport more specifically, primarily due to reduced flux and velocity, but did not affect transport of other organelles. To understand the mechanisms underlying these effects, we examined Ca2+ levels and the JNK (c-Jun N-terminal Kinase) pathway, which have been shown to regulate mitochondrial transport and general fast axonal transport, respectively. We found that elevated ROS increased Ca2+ levels, and that experimental reduction of Ca2+ to physiological levels rescued ROS-induced defects in mitochondrial transport in primary neuron cell cultures. In addition, in vivo activation of the JNK pathway reduced mitochondrial flux and velocities, while JNK knockdown partially rescued ROS-induced defects in the anterograde direction. We conclude that ROS have the capacity to regulate mitochondrial traffic, and that Ca2+ and JNK signaling play roles in mediating these effects. In addition to transport defects, ROS produces imbalances in mitochondrial fission-fusion and metabolic state, indicating that mitochondrial transport, fission-fusion steady state, and metabolic state are closely interrelated in the response to ROS. PMID:28542430

Mitochondrial reactive oxygen species and complex II levels are associated with the outcome of hepatocellular carcinoma

PubMed Central

WU, JIANHUA; ZHAO, FEI; ZHAO, YUFEI; GUO, ZHANJUN

2015-01-01

In the present study, two oxidative stress parameters, reactive oxygen species (ROS) and mitochondrial respiratory complex II, were evaluated in the mitochondria of hepatocellular carcinoma (HCC) cells to determine the association between these parameters and the carcinogenesis and clinical outcome of HCC. High levels of ROS and low levels of complex II were found to be associated with reduced post-operative survival in HCC patients using the log-rank test. Furthermore, multivariate analysis confirmed that the levels of ROS [relative risk (RR)=2.867; 95% confidence interval (CI), 1.062–7.737; P=0.038] and complex II (RR=5.422; 95% CI, 1.273–23.088; P=0.022) were independent predictors for the survival of patients with HCC. Therefore, the analysis of ROS and complex II levels may provide a useful research and therapeutic tool for the prediction of HCC prognosis and treatment. PMID:26622849

Estrogen receptor α activation enhances its cell surface localization and improves myocardial redox status in ovariectomized rats.

PubMed

Steagall, Rebecca J; Yao, Fanrong; Shaikh, Saame Raza; Abdel-Rahman, Abdel A

2017-08-01

Little is known about the role of subcellular trafficking of estrogen receptor (ER) subtypes in the acute estrogen (E 2 )-mediated alleviation of oxidative stress. We tested the hypothesis that ERα migration to the cardiac myocyte membrane mediates the acute E 2 -dependent improvement of cellular redox status. Myocardial distribution of subcellular ERα, ERβ and G-protein coupled estrogen receptor (GPER) was determined in proestrus sham-operated (SO) and in ovariectomized (OVX) rats, acutely treated with E 2 (1μg/kg) or a selective ERα (PPT), ERβ (DPN) or GPER (G1) agonist (10μg/kg), by immunofluorescence and Western blot. We measured ROS and malondialdehyde (MDA) levels, and catalase and superoxide dismutase (SOD) activities to evaluate myocardial antioxidant/redox status. Compared with SO, OVX rats exhibited higher myocardial ROS and MDA levels, reduced catalase and SOD activities, along with diminished ERα, and enhanced ERβ and GPER, localization at cardiomyocyte membrane. Acute E 2 or an ERα (PPT), but not ERβ (DPN) or GPER (G1), agonist reversed these responses in OVX rats and resulted in higher ERα/ERβ and ERα/GPER ratios at the cardiomyocytes membrane. PPT or DPN enhanced myocardial Akt phosphorylation. We present the first evidence that preferential aggregation of ERα at the cardiomyocytes plasma membrane is ERα-dependent, and underlies E 2 -mediated reduction in oxidative stress, at least partly, via the enhancements of myocardial catalase and SOD activities in OVX rats. The findings highlight ERα agonists as potential therapeutics for restoring the myocardial redox status following E 2 depletion in postmenopausal women. Copyright © 2017 Elsevier Inc. All rights reserved.

Arctigenin enhances swimming endurance of sedentary rats partially by regulation of antioxidant pathways.

PubMed

Wu, Ruo-ming; Sun, Yan-yan; Zhou, Ting-ting; Zhu, Zhi-yuan; Zhuang, Jing-jing; Tang, Xuan; Chen, Jing; Hu, Li-hong; Shen, Xu

2014-10-01

Arctigenin, a phenylpropanoid dibenzylbutyrolactone lignan found in traditional Chinese herbs, has been determined to exhibit a variety of pharmacological activities, including anti-tumor, anti-inflammation, neuroprotection, and endurance enhancement. In the present study, we investigated the antioxidation and anti-fatigue effects of arctigenin in rats. Rat L6 skeletal muscle cell line was exposed to H2O2 (700 μmol/L), and ROS level was assayed using DCFH-DA as a probe. Male SD rats were injected with arctigenin (15 mg·kg(-1)·d(-1), ip) for 6 weeks, and then the weight-loaded forced swimming test (WFST) was performed to evaluate their endurance. The levels of antioxidant-related genes in L6 cells and the skeletal muscles of rats were analyzed using real-time RT-PCR and Western blotting. Incubation of L6 cells with arctigenin (1, 5, 20 μmol/L) dose-dependently decreased the H2O2-induced ROS production. WFST results demonstrated that chronic administration of arctigenin significantly enhanced the endurance of rats. Furthermore, molecular biology studies on L6 cells and skeletal muscles of the rats showed that arctigenin effectively increased the expression of the antioxidant-related genes, including superoxide dismutase (SOD), glutathione reductase (Gsr), glutathione peroxidase (GPX1), thioredoxin (Txn) and uncoupling protein 2 (UCP2), through regulation of two potential antioxidant pathways: AMPK/PGC-1α/PPARα in mitochondria and AMPK/p53/Nrf2 in the cell nucleus. Arctigenin efficiently enhances rat swimming endurance by elevation of the antioxidant capacity of the skeletal muscles, which has thereby highlighted the potential of this natural product as an antioxidant in the treatment of fatigue and related diseases.

Arctigenin enhances swimming endurance of sedentary rats partially by regulation of antioxidant pathways

PubMed Central

Wu, Ruo-ming; Sun, Yan-yan; Zhou, Ting-ting; Zhu, Zhi-yuan; Zhuang, Jing-jing; Tang, Xuan; Chen, Jing; Hu, Li-hong; Shen, Xu

2014-01-01

Aim: Arctigenin, a phenylpropanoid dibenzylbutyrolactone lignan found in traditional Chinese herbs, has been determined to exhibit a variety of pharmacological activities, including anti-tumor, anti-inflammation, neuroprotection, and endurance enhancement. In the present study, we investigated the antioxidation and anti-fatigue effects of arctigenin in rats. Methods: Rat L6 skeletal muscle cell line was exposed to H2O2 (700 μmol/L), and ROS level was assayed using DCFH-DA as a probe. Male SD rats were injected with arctigenin (15 mg·kg−1·d−1, ip) for 6 weeks, and then the weight-loaded forced swimming test (WFST) was performed to evaluate their endurance. The levels of antioxidant-related genes in L6 cells and the skeletal muscles of rats were analyzed using real-time RT-PCR and Western blotting. Results: Incubation of L6 cells with arctigenin (1, 5, 20 μmol/L) dose-dependently decreased the H2O2-induced ROS production. WFST results demonstrated that chronic administration of arctigenin significantly enhanced the endurance of rats. Furthermore, molecular biology studies on L6 cells and skeletal muscles of the rats showed that arctigenin effectively increased the expression of the antioxidant-related genes, including superoxide dismutase (SOD), glutathione reductase (Gsr), glutathione peroxidase (GPX1), thioredoxin (Txn) and uncoupling protein 2 (UCP2), through regulation of two potential antioxidant pathways: AMPK/PGC-1α/PPARα in mitochondria and AMPK/p53/Nrf2 in the cell nucleus. Conclusion: Arctigenin efficiently enhances rat swimming endurance by elevation of the antioxidant capacity of the skeletal muscles, which has thereby highlighted the potential of this natural product as an antioxidant in the treatment of fatigue and related diseases. PMID:25152028

Nanopriming technology for enhancing germination and starch metabolism of aged rice seeds using phytosynthesized silver nanoparticles.

PubMed

Mahakham, Wuttipong; Sarmah, Ajit K; Maensiri, Santi; Theerakulpisut, Piyada

2017-08-15

Application of nanomaterials for agriculture is relatively new as compared to their use in biomedical and industrial sectors. In order to promote sustainable nanoagriculture, biocompatible silver nanoparticles (AgNPs) have been synthesized through green route using kaffir lime leaf extract for use as nanopriming agent for enhancing seed germination of rice aged seeds. Results of various characterization techniques showed the successful formation of AgNPs which were capped with phytochemicals present in the plant extract. Rice aged seeds primed with phytosynthesized AgNPs at 5 and 10 ppm significantly improved germination performance and seedling vigor compared to unprimed control, AgNO 3 priming, and conventional hydropriming. Nanopriming could enhance α-amylase activity, resulting in higher soluble sugar content for supporting seedlings growth. Furthermore, nanopriming stimulated the up-regulation of aquaporin genes in germinating seeds. Meanwhile, more ROS production was observed in germinating seeds of nanopriming treatment compared to unprimed control and other priming treatments, suggesting that both ROS and aquaporins play important roles in enhancing seed germination. Different mechanisms underlying nanopriming-induced seed germination were proposed, including creation of nanopores for enhanced water uptake, rebooting ROS/antioxidant systems in seeds, generation of hydroxyl radicals for cell wall loosening, and nanocatalyst for fastening starch hydrolysis.

Real-time in vivo detection of biomaterial-induced reactive oxygen species.

PubMed

Liu, Wendy F; Ma, Minglin; Bratlie, Kaitlin M; Dang, Tram T; Langer, Robert; Anderson, Daniel G

2011-03-01

The non-specific host response to implanted biomaterials is often a key challenge of medical device design. To evaluate biocompatibility, measuring the release of reactive oxygen species (ROS) produced by inflammatory cells in response to biomaterial surfaces is a well-established method. However, the detection of ROS in response to materials implanted in vivo has not yet been demonstrated. Here, we develop a bioluminescence whole animal imaging approach to observe ROS released in response to subcutaneously-implanted materials in live animals. We compared the real-time generation of ROS in response to two representative materials, polystyrene and alginate, over the course of 28 days. High levels of ROS were observed near polystyrene, but not alginate implants, and persisted throughout the course of 28 days. Histological analysis revealed that high levels of ROS correlated not only with the presence of phagocytic cells at early timepoints, but also fibrosis at later timepoints, suggesting that ROS may be involved in both the acute and chronic phase of the foreign body response. These data are the first in vivo demonstration of ROS generation in response to implanted materials, and describe a novel technique to evaluate the host response. Copyright © 2010 Elsevier Ltd. All rights reserved.

Targeting reactive oxygen species in development and progression of pancreatic cancer

PubMed Central

Durand, Nisha; Storz, Peter

2017-01-01

Introduction Pancreatic ductal adenocarcinoma (PDA) is characterized by expression of oncogenic KRas which drives all aspects of tumorigenesis. Oncogenic KRas induces the formation of reactive oxygen species (ROS) which have been implicated in initiation and progression of PDA. To facilitate tumor promoting levels and to avoid oncogene-induced senescence or cytotoxicity, ROS homeostasis in PDA cells is balanced by additional up-regulation of antioxidant systems. Areas Covered We examine the sources of ROS in PDA, the mechanisms by which ROS homeostasis is maintained, and the biological consequences of ROS in PDA. Additionally, we discuss the potential mechanisms for targeting ROS homoeostasis as a point of therapeutic intervention. An extensive review of the relevant literature as it relates to the topic was conducted using PubMed. Expert Commentary Even though oncogenic mutations in the KRAS gene have been detected in over 95% of human pancreatic adenocarcinoma, targeting its gene product, KRas, has been difficult. The dependency of PDA cells on balancing ROS homeostasis could be an angle for new prevention or treatment strategies. These include use of antioxidants to prevent formation or progression of precancerous lesions, or methods to increase ROS in tumor cells to toxic levels. PMID:27841037

PGC1α is required for the induction of contact inhibition by suppressing ROS.

PubMed

Yang, Seungyeon; Hwang, Sunsook; Jang, Jiho; Kim, Minjoong; Gwak, Jihye; Jeong, Seung Min

2018-05-16

Contact inhibition (CI) is an important tumor-suppressive mechanism that arrests cell cycle when cells reach high density. Indeed, CI is aberrantly absent in cancer cells and the dysregulation of this can contribute to tumorigenesis. Previously, it has been shown that reactive oxygen species (ROS) levels are repressed at high cell density, which is required for CI, but no molecular mechanism of this ROS regulation has been reported. Here, we show that PGC1α regulates cell density-dependent CI. PGC1α is markedly induced in response to high cell density and suppresses ROS production. Although cellular ROS levels are progressively decreased with increasing cell density, knockdown of PGC1α results in a defect of density-dependent ROS suppression. Importantly, PGC1α knockdown cells become less sensitive to high cell density and exhibit loss of CI. Mechanistically, PGC1α represses ROS production by inducing mitochondrial SIRT3, and thus SIRT3 overexpression rescues the defects of CI by PGC1α knockdown. These results demonstrate that mitochondrial ROS production is a crucial regulator of cell proliferation and identify a new role of PGC1α in CI. Copyright © 2018 Elsevier Inc. All rights reserved.

Selected Activities of Citrus Maxima Merr. Fruits on Human Endothelial Cells: Enhancing Cell Migration and Delaying Cellular Aging

PubMed Central

Buachan, Paiwan; Chularojmontri, Linda; Wattanapitayakul, Suvara K.

2014-01-01

Endothelial injury and damage as well as accumulated reactive oxygen species (ROS) in aging play a significant role in the development of cardiovascular disease (CVD). Recent studies show an association of high citrus fruit intake with a lower risk of CVD and stroke but the mechanisms involved are not fully understood. This study investigated the effects of pummelo (Citrus maxima Merr. var. Tubtim Siam, CM) fruit extract on human umbilical vein endothelial cell (HUVECs) migration and aging. The freeze-dried powder of fruit extract was characterized for antioxidant capacity (FRAP assay) and certain natural antioxidants, including ascorbic acid, gallic acid, hesperidin, and naringin (HPLC). Short-term (48 h) co-cultivation of HUVECs with CM enhanced cell migration as evaluated by a scratch wound assay and Boyden chamber assay. A long-term treatment with CM for 35 days significantly increased HUVEC proliferation capability as indicated by population doubling level (PDL). CM also delayed the onset of aging phenotype shown by senescence-associated β-galactosidase (SA-β-gal) staining. Furthermore, CM was able to attenuate increased ROS levels in aged cells when determined by 2′,7′-dichlorodihydrofluorescein diacetate (DCDHF) while eNOS mRNA expression was increased but the eNOS protein level was not changed. Thus, further in vivo and clinical studies are warranted to support the use of pummelo as a functional fruit for endothelial health and CVD risk reduction. PMID:24763109

Selected activities of Citrus maxima Merr. fruits on human endothelial cells: enhancing cell migration and delaying cellular aging.

PubMed

Buachan, Paiwan; Chularojmontri, Linda; Wattanapitayakul, Suvara K

2014-04-21

Endothelial injury and damage as well as accumulated reactive oxygen species (ROS) in aging play a significant role in the development of cardiovascular disease (CVD). Recent studies show an association of high citrus fruit intake with a lower risk of CVD and stroke but the mechanisms involved are not fully understood. This study investigated the effects of pummelo (Citrus maxima Merr. var. Tubtim Siam, CM) fruit extract on human umbilical vein endothelial cell (HUVECs) migration and aging. The freeze-dried powder of fruit extract was characterized for antioxidant capacity (FRAP assay) and certain natural antioxidants, including ascorbic acid, gallic acid, hesperidin, and naringin (HPLC). Short-term (48 h) co-cultivation of HUVECs with CM enhanced cell migration as evaluated by a scratch wound assay and Boyden chamber assay. A long-term treatment with CM for 35 days significantly increased HUVEC proliferation capability as indicated by population doubling level (PDL). CM also delayed the onset of aging phenotype shown by senescence-associated β-galactosidase (SA-β-gal) staining. Furthermore, CM was able to attenuate increased ROS levels in aged cells when determined by 2',7'-dichlorodihydrofluorescein diacetate (DCDHF) while eNOS mRNA expression was increased but the eNOS protein level was not changed. Thus, further in vivo and clinical studies are warranted to support the use of pummelo as a functional fruit for endothelial health and CVD risk reduction.

Neferine augments therapeutic efficacy of cisplatin through ROS- mediated non-canonical autophagy in human lung adenocarcinoma (A549 cells).

PubMed

Kalai Selvi, Sivalingam; Vinoth, Amirthalingam; Varadharajan, Thiyagarajan; Weng, Ching Feng; Vijaya Padma, Viswanadha

2017-05-01

Combination of dietary components with chemotherapy drugs is an emerging new strategy for cancer therapy to increase antitumor responses. Neferine, major bisbenzylisoquinoline alkaloid isolated from the seed embryo of Nelumbo nucifera (Lotus). In the present study, we investigated the efficacy of the combinatorial regimen of neferine and cisplatin compared to cisplatin high dose in human lung adenocarcinoma (A549) cells. Co-treatment with neferine enhanced cisplatin-induced autophagy in A549 cells was accompanied by Acidic vesicular accumulation (AVO), enhanced generation of reactive oxygen species (ROS) and depletion of intracellular glutathione (GSH), down regulation of PI3K/AKT/mTOR pathway, conversion of LC3B-I to LC3B-II. This enhanced autophagy developed via a non-canonical mechanism that did not require Beclin-1, PI3KCIII. In conclusion, these results suggest that neferine enhances cisplatin -induced autophagic cancer cell death through downregulation of PI3K/Akt/mTOR signaling pro-survival pathway and ROS- mediated Beclin-1 and PI3K CIII independent autophagy in human lung adenocarcinoma (A549 cells). Copyright © 2017 Elsevier Ltd. All rights reserved.

Non-thermal dielectric barrier discharge plasma induces angiogenesis through reactive oxygen species.

PubMed

Arjunan, Krishna P; Clyne, Alisa Morss

2011-01-01

Vascularization plays a key role in processes such as wound healing and tissue engineering. Non-thermal plasma, which primarily produces reactive oxygen species (ROS), recently emerged as an efficient tool in medical applications. Liquids and endothelial cells were treated with a non-thermal dielectric barrier discharge plasma. Plasma treatment of phosphate buffered saline (PBS) and serum-free medium increased ROS concentration in a dose-dependent manner, with a higher concentration in serum-free medium. ROS concentration in cells peaked 1 hour after treatment. 4.2 J/cm(2) increased cell proliferation, 2D and 3D migration, as well as tube formation. A fibroblast growth factor-2 (FGF-2) neutralizing antibody and ROS scavengers for hydrogen peroxide and hydroxyl radicals abrogated these angiogenic effects. Non-thermal plasma may be a potential tool for applying ROS in precise doses to enhance vascularization.

PRX1 knockdown potentiates vitamin K3 toxicity in cancer cells: a potential new therapeutic perspective for an old drug.

PubMed

He, Tiantian; Hatem, Elie; Vernis, Laurence; Lei, Ming; Huang, Meng-Er

2015-12-21

Many promising anticancer molecules are abandoned during the course from bench to bedside due to lack of clear-cut efficiency and/or severe side effects. Vitamin K3 (vitK3) is a synthetic naphthoquinone exhibiting significant in vitro and in vivo anticancer activity against multiple human cancers, and has therapeutic potential when combined with other anticancer molecules. The major mechanism for the anticancer activity of vitK3 is the generation of cytotoxic reactive oxygen species (ROS). We thus reasoned that a rational redox modulation of cancer cells could enhance vitK3 anticancer efficiency. Cancer cell lines with peroxiredoxin 1 (PRX1) gene transiently or stably knocked-down and corresponding controls were exposed to vitK3 as well as a set of anticancer molecules, including vinblastine, taxol, doxorubicin, daunorubicin, actinomycin D and 5-fluorouracil. Cytotoxic effects and cell death events were evaluated by 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide (MTT)-based assay, cell clonogenic assay, measurement of mitochondrial membrane potential and annexin V/propidium iodide double staining. Global ROS accumulation and compartment-specific H2O2 generation were determined respectively by a redox-sensitive chemical probe and H2O2-sensitive sensor HyPer. Oxidation of endogenous antioxidant proteins including TRX1, TRX2 and PRX3 was monitored by redox western blot. We observed that the PRX1 knockdown in HeLa and A549 cells conferred enhanced sensitivity to vitK3, reducing substantially the necessary doses to kill cancer cells. The same conditions (combination of vitK3 and PRX1 knockdown) caused little cytotoxicity in non-cancerous cells, suggesting a cancer-cell-selective property. Increased ROS accumulation had a crucial role in vitK3-induced cell death in PRX1 knockdown cells. The use of H2O2-specific sensors HyPer revealed that vitK3 lead to immediate accumulation of H2O2 in the cytosol, nucleus, and mitochondrial matrix. PRX1 silencing significantly up-regulated mRNA and protein levels of NRH:quinone oxidoreductase 2, which was partially responsible for vitK3-induced ROS accumulation and consequent cell death. Our data suggest that PRX1 inactivation could represent an interesting strategy to enhance cancer cell sensitivity to vitK3, providing a potential new therapeutic perspective for this old molecule. Conceptually, a combination of drugs that modulate intracellular redox states and drugs that operate through the generation of ROS could be a new therapeutic strategy for cancer treatment.

Reactive oxygen species mediate growth and death in submerged plants

PubMed Central

Steffens, Bianka; Steffen-Heins, Anja; Sauter, Margret

2013-01-01

Aquatic and semi-aquatic plants are well adapted to survive partial or complete submergence which is commonly accompanied by oxygen deprivation. The gaseous hormone ethylene controls a number of adaptive responses to submergence including adventitious root growth and aerenchyma formation. Reactive oxygen species (ROS) act as signaling intermediates in ethylene-controlled submergence adaptation and possibly also independent of ethylene. ROS levels are controlled by synthesis, enzymatic metabolism, and non-enzymatic scavenging. While the actors are by and large known, we still have to learn about altered ROS at the subcellular level and how they are brought about, and the signaling cascades that trigger a specific response. This review briefly summarizes our knowledge on the contribution of ROS to submergence adaptation and describes spectrophotometrical, histochemical, and live cell imaging detection methods that have been used to study changes in ROS abundance. Electron paramagnetic resonance (EPR) spectroscopy is introduced as a method that allows identification and quantification of specific ROS in cell compartments. The use of advanced technologies such as EPR spectroscopy will be necessary to untangle the intricate and partially interwoven signaling networks of ethylene and ROS. PMID:23761805

The Effect of Reactive Oxygen Species on Embryo Quality in IVF.

PubMed

Siristatidis, Charalampos; Vogiatzi, Paraskevi; Varounis, Christos; Askoxylaki, Marily; Chrelias, Charalampos; Papantoniou, Nikolaos

2016-01-01

BACKROUND/AIM: Reactive oxygen species (ROS) are involved in critical biological processes in human reproduction. The aim of this study was to evaluate the association of embryo quality following in vitro fertilization (IVF), with ROS levels in the serum and follicular fluid (FF). Eighty-five participants underwent ovarian stimulation and IVF; ROS levels were measured in blood samples on the day of oocyte retrieval and in the FF from follicular aspirates using enzyme-linked immunosorbent assay. These values were associated with the quality of embryos generated. Univariable zero-inflated Poisson model revealed that ROS levels at both oocyte retrieval and in FF were not associated with the number of grade I, II, III and IV embryos (p>0.05). Age, body mass index, stimulation protocol and smoking status were not associated with the number of embryos of any grade (p>0.05). Neither ROS levels in serum nor in FF are associated with the quality of embryos produced following IVF. Copyright © 2016 International Institute of Anticancer Research (Dr. John G. Delinassios), All rights reserved.

On/off-switchable anti-neoplastic nanoarchitecture

NASA Astrophysics Data System (ADS)

Patra, Hirak K.; Imani, Roghayeh; Jangamreddy, Jaganmohan R.; Pazoki, Meysam; Iglič, Aleš; Turner, Anthony P. F.; Tiwari, Ashutosh

2015-09-01

Throughout the world, there are increasing demands for alternate approaches to advanced cancer therapeutics. Numerous potentially chemotherapeutic compounds are developed every year for clinical trial and some of them are considered as potential drug candidates. Nanotechnology-based approaches have accelerated the discovery process, but the key challenge still remains to develop therapeutically viable and physiologically safe materials suitable for cancer therapy. Here, we report a high turnover, on/off-switchable functionally popping reactive oxygen species (ROS) generator using a smart mesoporous titanium dioxide popcorn (TiO2 Pops) nanoarchitecture. The resulting TiO2 Pops, unlike TiO2 nanoparticles (TiO2 NPs), are exceptionally biocompatible with normal cells. Under identical conditions, TiO2 Pops show very high photocatalytic activity compared to TiO2 NPs. Upon on/off-switchable photo activation, the TiO2 Pops can trigger the generation of high-turnover flash ROS and can deliver their potential anticancer effect by enhancing the intracellular ROS level until it crosses the threshold to open the ‘death gate’, thus reducing the survival of cancer cells by at least six times in comparison with TiO2 NPs without affecting the normal cells.

On/off-switchable anti-neoplastic nanoarchitecture

PubMed Central

Patra, Hirak K.; Imani, Roghayeh; Jangamreddy, Jaganmohan R.; Pazoki, Meysam; Iglič, Aleš; Turner, Anthony P. F.; Tiwari, Ashutosh

2015-01-01

Throughout the world, there are increasing demands for alternate approaches to advanced cancer therapeutics. Numerous potentially chemotherapeutic compounds are developed every year for clinical trial and some of them are considered as potential drug candidates. Nanotechnology-based approaches have accelerated the discovery process, but the key challenge still remains to develop therapeutically viable and physiologically safe materials suitable for cancer therapy. Here, we report a high turnover, on/off-switchable functionally popping reactive oxygen species (ROS) generator using a smart mesoporous titanium dioxide popcorn (TiO2 Pops) nanoarchitecture. The resulting TiO2 Pops, unlike TiO2 nanoparticles (TiO2 NPs), are exceptionally biocompatible with normal cells. Under identical conditions, TiO2 Pops show very high photocatalytic activity compared to TiO2 NPs. Upon on/off-switchable photo activation, the TiO2 Pops can trigger the generation of high-turnover flash ROS and can deliver their potential anticancer effect by enhancing the intracellular ROS level until it crosses the threshold to open the ‘death gate’, thus reducing the survival of cancer cells by at least six times in comparison with TiO2 NPs without affecting the normal cells. PMID:26415561

Acetoacetate promotes the formation of fluorescent advanced glycation end products (AGEs).

PubMed

Bohlooli, Mousa; Ghaffari-Moghaddam, Mansour; Khajeh, Mostafa; Aghashiri, Zohre; Sheibani, Nader; Moosavi-Movahedi, Ali Akbar

2016-12-01

Acetoacetate (AA) is an important ketone body, which produces reactive oxygen species (ROS). Advanced glycation end products (AGEs) are defined as final products of glycation process whose production is influenced by the levels of ROS. The accumulation of AGEs in the body contributes to pathogenesis of many diseases including complications of diabetes, and Alzheimer's and Parkinson's disease. Here, we evaluated the impact of AA on production of AGEs upon incubation of human serum albumin (HSA) with glucose. The effect of AA on the AGEs formation of HSA was studied under physiological conditions after incubation with glucose for 35 days. The physical techniques including circular dichroism (CD) and fluorescence spectroscopy were used to assess the impact of AA on formation and structural changes of glycated HSA (GHSA). Our results indicated that the secondary and tertiary structural changes of GHSA were increased in the presence of AA. The fluorescence intensity measurements of AGEs also showed an increase in AGEs formation. Acetoacetate has an activator effect in formation of AGEs through ROS production. The presence of AA may result in enhanced glycation in the presence of glucose and severity of complications associated with accumulation of AGEs.

Fighting down the scourge, building up the church: Organisational constraints in religious involvement with HIV/AIDS in Mozambique

PubMed Central

Agadjanian, Victor; Menjívar, Cecilia

2011-01-01

Religious organisations (ROs) are often said to play an important role in mitigating the impact of HIV/AIDS. Yet, limitations of that role have also been acknowledged. While most of the literature has focused on ideological and individual-level implications of religion for HIV/AIDS, in this study, we shift the focus to the organisational factors that shape and constrain ROs' involvement in both HIV prevention and HIV/AIDS care and support. Using primarily qualitative data collected in a predominantly Christian area in southern Mozambique, we show that the organisational vitality of a RO as determined by its membership size and its relationships with other churches and with governmental and non-governmental agencies is a pervasive priority of RO leaders. Therefore, all church activities, including those related to HIV/AIDS, are instrumentalised by the religious leadership to achieve the church's organisational aims—maintaining and growing its membership, safeguarding the often precarious coexistence with other churches, and enhancing its standing vis-à-vis the government and powerful non-governmental organisations. As a result, the effectiveness of ROs' involvement in HIV/AIDS prevention and assistance is often compromised. PMID:21787253

TRAIL Enhances Shikonin Induced Apoptosis through ROS/JNK Signaling in Cholangiocarcinoma Cells.

PubMed

Zhou, Guangyao; Yang, Zuqin; Wang, Xiaodong; Tao, Ran; Zhou, Yuanping

2017-01-01

Cholangiocarcinoma (CCA), arising from varying locations within the biliary tree, is the second most common primary liver malignancy worldwide. Shikonin, an active compound extracted from the Chinese herb Zicao, holds anti-bacterial, anti-inflammatory, and anti-tumor activities. However, the effect of shikonin on human cholangiocarcinoma and detailed mechanisms of TRAIL enhancement remains to be elucidated. The purpose of the study was to investigate the protective functions of TRAIL enhancement for shikonin induced apoptosis in cholangiocarcinoma cells. We use MTT assay, apoptosis assay, caspase activity assay, flow cytometry assay, real time PCR and Western blot to observe the effects of TRAIL on shikonin induced cholangiocarcinoma cells apoptosis and its mechanism. Shikonin inhibited cell viability and induced apoptosis of CCA cells, effects enhanced by TRAIL treatment via activation of caspase-3, -8, -9. Furhermore, TRAIL enhanced anti-proliferation of shikonin and shikonin induced apoptosis through induction of ROS mediated JNK activation, while AKT activation had an effect on shikonin anti-proliferation activity, but not in the TRAIL enhanced counterparts. Finally, shikonin upregulated DR5 expression, an effect essential for TRAIL-enhanced activities of shikonin in RBE cells. Our results revealed that shikonin could inhibit cells viability and induce apoptosis of CCA cells, effects enhanced by TRAIL treatment via ROS mediated JNK signalling pathways, involving up-regulation of DR5 expression. Our results provide further insight into the mechanism underlying the anti-tumor effects of shikonin by TRAIL enhanced in CCA and a new therapeutic strategy to CCA treatment. © 2017 The Author(s). Published by S. Karger AG, Basel.

Combined Treatment With Peroxisome Proliferator-Activated Receptor (PPAR) Gamma Ligands and Gamma Radiation Induces Apoptosis by PPARγ-Independent Up-Regulation of Reactive Oxygen Species-Induced Deoxyribonucleic Acid Damage Signals in Non-Small Cell Lung Cancer Cells

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

Han, Eun Jong; Im, Chang-Nim; Park, Seon Hwa

2013-04-01

Purpose: To investigate possible radiosensitizing activities of the well-known peroxisome proliferator-activated receptor (PPAR)γ ligand ciglitazone and novel PPARγ ligands CAY10415 and CAY10506 in non-small cell lung cancer (NSCLC) cells. Methods and Materials: Radiosensitivity was assessed using a clonogenic cell survival assay. To investigate the mechanism underlying PPARγ ligand-induced radiosensitization, the subdiploid cellular DNA fraction was analyzed by flow cytometry. Activation of the caspase pathway by combined PPARγ ligands and γ-radiation treatment was detected by immunoblot analysis. Reactive oxygen species (ROS) were measured using 2,7-dichlorodihydrofluorescein diacetate and flow cytometry. Results: The 3 PPARγ ligands induced cell death and ROS generation inmore » a PPARγ-independent manner, enhanced γ-radiation–induced apoptosis and caspase-3–mediated poly (ADP-ribose) polymerase (PARP) cleavage in vitro. The combined PPARγ ligand/γ-radiation treatment triggered caspase-8 activation, and this initiator caspase played an important role in the combination-induced apoptosis. Peroxisome proliferator-activated receptor-γ ligands may enhance the γ-radiation-induced DNA damage response, possibly by increasing γ-H2AX expression. Moreover, the combination treatment significantly increased ROS generation, and the ROS scavenger N-acetylcysteine inhibited the combined treatment-induced ROS generation and apoptotic cell death. Conclusions: Taken together, these results indicated that the combined treatment of PPARγ ligands and γ-radiation synergistically induced DNA damage and apoptosis, which was regulated by ROS.« less

Overexpression of wheat ferritin gene TaFER-5B enhances tolerance to heat stress and other abiotic stresses associated with the ROS scavenging.

PubMed

Zang, Xinshan; Geng, Xiaoli; Wang, Fei; Liu, Zhenshan; Zhang, Liyuan; Zhao, Yue; Tian, Xuejun; Ni, Zhongfu; Yao, Yingyin; Xin, Mingming; Hu, Zhaorong; Sun, Qixin; Peng, Huiru

2017-01-14

The yield of wheat (Triticum aestivum L.), an important crop, is adversely affected by heat stress in many regions of the world. However, the molecular mechanisms underlying thermotolerance are largely unknown. A novel ferritin gene, TaFER, was identified from our previous heat stress-responsive transcriptome analysis of a heat-tolerant wheat cultivar (TAM107). TaFER was mapped to chromosome 5B and named TaFER-5B. Expression pattern analysis revealed that TaFER-5B was induced by heat, polyethylene glycol (PEG), H 2 O 2 and Fe-ethylenediaminedi(o-hydroxyphenylacetic) acid (Fe-EDDHA). To confirm the function of TaFER-5B in wheat, TaFER-5B was transformed into the wheat cultivar Jimai5265 (JM5265), and the transgenic plants exhibited enhanced thermotolerance. To examine whether the function of ferritin from mono- and dico-species is conserved, TaFER-5B was transformed into Arabidopsis, and overexpression of TaFER-5B functionally complemented the heat stress-sensitive phenotype of a ferritin-lacking mutant of Arabidopsis. Moreover, TaFER-5B is essential for protecting cells against heat stress associated with protecting cells against ROS. In addition, TaFER-5B overexpression also enhanced drought, oxidative and excess iron stress tolerance associated with the ROS scavenging. Finally, TaFER-5B transgenic Arabidopsis and wheat plants exhibited improved leaf iron content. Our results suggest that TaFER-5B plays an important role in enhancing tolerance to heat stress and other abiotic stresses associated with the ROS scavenging.

CD44+CD24+ subset of PANC-1 cells exhibits radiation resistance via decreased levels of reactive oxygen species.

PubMed

Wang, Lei; Li, Pengping; Hu, Wei; Xia, Youyou; Hu, Chenxi; Liu, Liang; Jiang, Xiaodong

2017-08-01

Emerging evidence has suggested that pancreatic adenocarcinoma is sustained by pancreatic cancer stem cells. The present study aimed to investigate the expression patterns of the pancreatic cancer stem cell surface markers cluster of differentiation CD44 and CD24 in a pancreatic adenocarcinoma cell line, and to investigate the possible mechanisms for their radiation resistance. Flow cytometry was used to analyze the expression patterns of CD44 and CD24 in the pancreatic adenocarcinoma PANC-1 cell line. In addition, a multi-target click model was used to fit cell survival curves and determine the sensitizer enhancement ratio. The apoptosis and cycle distribution of the four cell subsets was determined using flow cytometry, and the level of reactive oxygen species (ROS) was determined using the 2',7'-dichlorofluorescin diacetate probe. The present results identified that the ratios of CD44 + and CD24 + in the sorted PANC-1 cell line were 92.0 and 4.7%, respectively. Prior to radiation, no statistically significant differences were observed among the four groups. Following treatment with 6 MV of X-rays, the rate of apoptosis was decreased in the CD44 + CD24 + group compared with other subsets. The percentage of G0/G1 cells was highest in the CD44 + CD24 + group compared with the three other groups, which exhibited increased radiosensitivity. In addition, the level of ROS in the CD44 + CD24 + group was reduced compared with the other groups. In summary, the results of the present study indicated that CD44 + CD24 + exhibited stem cell properties. The lower level of ROS and apoptosis in CD44 + CD24 + cells may contribute to their resistance to radiation in pancreatic adenocarcinoma.

MAPK14/p38α-dependent modulation of glucose metabolism affects ROS levels and autophagy during starvation.

PubMed

Desideri, Enrico; Vegliante, Rolando; Cardaci, Simone; Nepravishta, Ridvan; Paci, Maurizio; Ciriolo, Maria Rosa

2014-09-01

Increased glycolytic flux is a common feature of many cancer cells, which have adapted their metabolism to maximize glucose incorporation and catabolism to generate ATP and substrates for biosynthetic reactions. Indeed, glycolysis allows a rapid production of ATP and provides metabolic intermediates required for cancer cells growth. Moreover, it makes cancer cells less sensitive to fluctuations of oxygen tension, a condition usually occurring in a newly established tumor environment. Here, we provide evidence for a dual role of MAPK14 in driving a rearrangement of glucose metabolism that contributes to limiting reactive oxygen species (ROS) production and autophagy activation in condition of nutrient deprivation. We demonstrate that MAPK14 is phosphoactivated during nutrient deprivation and affects glucose metabolism at 2 different levels: on the one hand, it increases SLC2A3 mRNA and protein levels, resulting in a higher incorporation of glucose within the cell. This event involves the MAPK14-mediated enhancement of HIF1A protein stability. On the other hand, MAPK14 mediates a metabolic shift from glycolysis to the pentose phosphate pathway (PPP) through the modulation of PFKFB3 (6-phosphofructo-2-kinase/fructose 2,6-bisphosphatase 3) degradation by the proteasome. This event requires the presence of 2 distinct degradation sequences, KEN box and DSG motif Ser273, which are recognized by 2 different E3 ligase complexes. The mutation of either motif increases PFKFB3 resistance to starvation-induced degradation. The MAPK14-driven metabolic reprogramming sustains the production of NADPH, an important cofactor for many reduction reactions and for the maintenance of the proper intracellular redox environment, resulting in reduced levels of ROS. The final effect is a reduced activation of autophagy and an increased resistance to nutrient deprivation.

Emptying of Intracellular Calcium Pool and Oxidative Stress Imbalance Are Associated with the Glyphosate-Induced Proliferation in Human Skin Keratinocytes HaCaT Cells

PubMed Central

George, Jasmine; Shukla, Yogeshwer

2013-01-01

We demonstrated that glyphosate possesses tumor promoting potential in mouse skin carcinogenesis and SOD 1, calcyclin (S100A6), and calgranulin B (S100A9) have been associated with this potential, although the mechanism is unclear. We aimed to clarify whether imbalance in between [Ca2+]i levels and oxidative stress is associated with glyphosate-induced proliferation in human keratinocytes HaCaT cells. The [Ca2+]i levels, ROS generation, and expressions of G1/S cyclins, IP3R1, S100A6, S100A9, and SOD 1, and apoptosis-related proteins were investigated upon glyphosate exposure in HaCaT cells. Glyphosate (0.1 mM) significantly induced proliferation, decreases [Ca2+]i, and increases ROS generation in HaCaT cells, whereas antioxidant N-acetyl-L-cysteine (NAC) pretreatment reverts these effects which directly indicated that glyphosate induced cell proliferation by lowering [Ca2+]i levels via ROS generation. Glyphosate also enhanced the expression of G1/S cyclins associated with a sharp decrease in G0/G1 and a corresponding increase in S-phases. Additionally, glyphosate also triggers S100A6/S100A9 expression and decreases IP3R1 and SOD 1 expressions in HaCaT cells. Notably, Ca2+ suppression also prevented apoptotic related events including Bax/Bcl-2 ratio and caspases activation. This study highlights that glyphosate promotes proliferation in HaCaT cells probably by disrupting the balance in between [Ca2+]i levels and oxidative stress which in turn facilitated the downregulation of mitochondrial apoptotic signaling pathways. PMID:24073338

A crossover study of rosuvastatin and pitavastatin in patients with type 2 diabetes.

PubMed

Yanagi, Kazunori; Monden, Tsuyoshi; Ikeda, Shiori; Matsumura, Mihoko; Kasai, Kikuo

2011-02-01

The effects of a low dose of rosuvastatin (ROS) and pitavastatin (PIT) on lipid profiles and inflammation markers were assessed in subjects with type 2 diabetes mellitus. A total of 90 Japanese type 2 diabetes patients with hyperlipidemia (low-density lipoprotein cholesterol [LDL-C] ≥140 mg/dL) were enrolled in this study. They were randomly assigned to four groups with open-label treatment with ROS (2.5 mg daily) or PIT (2 mg daily); two groups were sequentially treated with both drugs, with crossover of medication after 12 weeks, and the other two groups underwent treatment with either ROS or PIT for 24 weeks. The primary endpoints were the percentage changes in LDL-C, high-density lipoprotein cholesterol (HDL-C) and triglyceride, and the LDL-C/HDL-C ratio. Both ROS and PIT lowered LDL-C and triglyceride, and increased HDL-C. In particular, significantly greater reduction in LDL-C was seen with ROS (-44.1%) than with PIT (-36.9%, P<0.01) in the crossover group from ROS to PIT, and the same result was detected in the crossover group from PIT (-34.8%) to ROS (-44.7%). The ratio of LDL-C/HDL-C was significantly reduced with ROS treatment (from 3.45 to 1.85) compared with that with PIT (from 3.45 to 2.22, P<0.01). Both ROS and PIT lowered plasma levels of high-sensitivity C-reactive protein (hsCRP), tumor necrosis factor (TNF)-alpha, and plasminogen activator inhibitor-1 (PAI-1). In addition, the hsCRP level with the administration of ROS was significantly improved compared with the administration of PIT. There was no significant correlation between changes in LDL-C and hsCRP, TNF-alpha, and PAI-1 levels. ROS and PIT did not have an adverse effect on glycemic control in type 2 diabetes patients. Therapy with both statins improved lipid profiles and reduced proinflammatory responses; however, 2.5 mg of ROS have a potent LDL-C-lowering and hsCRP-lowering effect compared with 2 mg of PIT in patients with diabetes.

Synergistic effect of hydrogen peroxide on polyploidization during the megakaryocytic differentiation of K562 leukemia cells by PMA

PubMed Central

Ojima, Yoshihiro; Duncan, Mark Thompson; Nurhayati, Retno Wahyu; Taya, Masahito; Miller, William Martin

2013-01-01

The human myelogenous cell line, K562 has been extensively used as a model for the study of megakaryocytic (MK) differentiation, which could be achieved by exposure to phorbol 12-myristate 13-acetate (PMA). In this study, real-time PCR analysis revealed that the expression of catalase (cat) was significantly repressed during MK differentiation of K562 cells induced by PMA. In addition, PMA increased the intracellular reactive oxygen species (ROS) concentration, suggesting that ROS was a key factor for PMA-induced differentiation. PMA-differentiated K562 cells were exposed to hydrogen peroxide (H2O2) to clarify the function of ROS during MK differentiation. Interestingly, the percentage of high-ploidy (DNA content >4N) cells with H2O2 was 34.8±2.3% at day 9, and was 70% larger than that without H2O2 (21.5±0.8%). Further, H2O2 addition during the first 3 days of PMA-induced MK differentiation had the greatest effect on polyploidization. In an effort to elucidate the mechanisms of enhanced polyploidization by H2O2, the BrdU assay clearly indicated that H2O2 suppressed the division of 4N cells into 2N cells, followed by the increased polyploidization of K562 cells. These findings suggest that the enhancement in polyploidization mediated by H2O2 is due to synergistic inhibition of cytokinesis with PMA. Although H2O2 did not increase ploidy during the MK differentiation of primary cells, we clearly observed that cat expression was repressed in both immature and mature primary MK cells, and that treatment with the antioxidant N-acetylcysteine effectively blocked and/or delayed the polyploidization of immature MK cells. Together, these findings suggest that MK cells are more sensitive to ROS levels during earlier stages of maturation. PMID:23770036

Synergistic effect of hydrogen peroxide on polyploidization during the megakaryocytic differentiation of K562 leukemia cells by PMA.

PubMed

Ojima, Yoshihiro; Duncan, Mark Thompson; Nurhayati, Retno Wahyu; Taya, Masahito; Miller, William Martin

2013-08-15

The human myelogenous cell line, K562 has been extensively used as a model for the study of megakaryocytic (MK) differentiation, which could be achieved by exposure to phorbol 12-myristate 13-acetate (PMA). In this study, real-time PCR analysis revealed that the expression of catalase (cat) was significantly repressed during MK differentiation of K562 cells induced by PMA. In addition, PMA increased the intracellular reactive oxygen species (ROS) concentration, suggesting that ROS was a key factor for PMA-induced differentiation. PMA-differentiated K562 cells were exposed to hydrogen peroxide (H2O2) to clarify the function of ROS during MK differentiation. Interestingly, the percentage of high-ploidy (DNA content >4N) cells with H2O2 was 34.8±2.3% at day 9, and was 70% larger than that without H2O2 (21.5±0.8%). Further, H2O2 addition during the first 3 days of PMA-induced MK differentiation had the greatest effect on polyploidization. In an effort to elucidate the mechanisms of enhanced polyploidization by H2O2, the BrdU assay clearly indicated that H2O2 suppressed the division of 4N cells into 2N cells, followed by the increased polyploidization of K562 cells. These findings suggest that the enhancement in polyploidization mediated by H2O2 is due to synergistic inhibition of cytokinesis with PMA. Although H2O2 did not increase ploidy during the MK differentiation of primary cells, we clearly observed that cat expression was repressed in both immature and mature primary MK cells, and that treatment with the antioxidant N-acetylcysteine effectively blocked and/or delayed the polyploidization of immature MK cells. Together, these findings suggest that MK cells are more sensitive to ROS levels during earlier stages of maturation. Copyright © 2013 Elsevier Inc. All rights reserved.

Heme oxygenase-1 protects endothelial cells from the toxicity of air pollutant chemicals

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

Lawal, Akeem O.; Zhang, Min; Dittmar, Michael

Diesel exhaust particles (DEPs) are a major component of diesel emissions, responsible for a large portion of their toxicity. In this study, we examined the toxic effects of DEPs on endothelial cells and the role of DEP-induced heme oxygenase-1 (HO-1) expression. Human microvascular endothelial cells (HMECs) were treated with an organic extract of DEPs from an automobile engine (A-DEP) or a forklift engine (F-DEP) for 1 and 4 h. ROS generation, cell viability, lactate dehydrogenase leakage, expression of HO-1, inflammatory genes, cell adhesion molecules and unfolded protein respone (UPR) gene were assessed. HO-1 expression and/or activity were inhibited by siRNAmore » or tin protoporphyrin (Sn PPIX) and enhanced by an expression plasmid or cobalt protoporphyrin (CoPPIX). Exposure to 25 μg/ml of A-DEP and F-DEP significantly induced ROS production, cellular toxicity and greater levels of inflammatory and cellular adhesion molecules but to a different degree. Inhibition of HO-1 enzymatic activity with SnPPIX and silencing of the HO-1 gene by siRNA enhanced DEP-induced ROS production, further decreased cell viability and increased expression of inflammatory and cell adhesion molecules. On the other hand, overexpression of the HO-1 gene by a pcDNA 3.1D/V5-HO-1 plasmid significantly mitigated ROS production, increased cell survival and decreased the expression of inflammatory genes. HO-1 expression protected HMECs from DEP-induced prooxidative and proinflammatory effects. Modulation of HO-1 expression could potentially serve as a therapeutic target in an attempt to inhibit the cardiovascular effects of ambient PM. - Highlights: • We examined the role of HO-1 expression on diesel exhaust particle (DEP) in endothelial cells. • DEPs exert cytotoxic and inflammatory effects on human microvascular endothelial cells (HMECs). • DEPs induce HO-1 expression in HMECs. • HO-1 protects against the oxidative stress induced by DEps. • HO-1 attenuates the proinflammatory effects induced by DEPs.« less

Insulin and IGF-1 improve mitochondrial function in a PI-3K/Akt-dependent manner and reduce mitochondrial generation of reactive oxygen species in Huntington's disease knock-in striatal cells.

PubMed

Ribeiro, Márcio; Rosenstock, Tatiana R; Oliveira, Ana M; Oliveira, Catarina R; Rego, A Cristina

2014-09-01

Oxidative stress and mitochondrial dysfunction have been described in Huntington's disease, a disorder caused by expression of mutant huntingtin (mHtt). IGF-1 was previously shown to protect HD cells, whereas insulin prevented neuronal oxidative stress. In this work we analyzed the role of insulin and IGF-1 in striatal cells derived from HD knock-in mice on mitochondrial production of reactive oxygen species (ROS) and related antioxidant and signaling pathways influencing mitochondrial function. Insulin and IGF-1 decreased mitochondrial ROS induced by mHtt and normalized mitochondrial SOD activity, without affecting intracellular glutathione levels. IGF-1 and insulin promoted Akt phosphorylation without changing the nuclear levels of phosphorylated Nrf2 or Nrf2/ARE activity. Insulin and IGF-1 treatment also decreased mitochondrial Drp1 phosphorylation, suggesting reduced mitochondrial fragmentation, and ameliorated mitochondrial function in HD cells in a PI-3K/Akt-dependent manner. This was accompanied by increased total and phosphorylated Akt, Tfam, and mitochondrial-encoded cytochrome c oxidase II, as well as Tom20 and Tom40 in mitochondria of insulin- and IGF-1-treated mutant striatal cells. Concomitantly, insulin/IGF-1-treated mutant cells showed reduced apoptotic features. Hence, insulin and IGF-1 improve mitochondrial function and reduce mitochondrial ROS caused by mHtt by activating the PI-3K/Akt signaling pathway, in a process independent of Nrf2 transcriptional activity, but involving enhanced mitochondrial levels of Akt and mitochondrial-encoded complex IV subunit. Copyright © 2014 Elsevier Inc. All rights reserved.

Reactive oxygen species and transcript analysis upon excess light treatment in wild-type Arabidopsis thaliana vs a photosensitive mutant lacking zeaxanthin and lutein

PubMed Central

2011-01-01

Background Reactive oxygen species (ROS) are unavoidable by-products of oxygenic photosynthesis, causing progressive oxidative damage and ultimately cell death. Despite their destructive activity they are also signalling molecules, priming the acclimatory response to stress stimuli. Results To investigate this role further, we exposed wild type Arabidopsis thaliana plants and the double mutant npq1lut2 to excess light. The mutant does not produce the xanthophylls lutein and zeaxanthin, whose key roles include ROS scavenging and prevention of ROS synthesis. Biochemical analysis revealed that singlet oxygen (1O2) accumulated to higher levels in the mutant while other ROS were unaffected, allowing to define the transcriptomic signature of the acclimatory response mediated by 1O2 which is enhanced by the lack of these xanthophylls species. The group of genes differentially regulated in npq1lut2 is enriched in sequences encoding chloroplast proteins involved in cell protection against the damaging effect of ROS. Among the early fine-tuned components, are proteins involved in tetrapyrrole biosynthesis, chlorophyll catabolism, protein import, folding and turnover, synthesis and membrane insertion of photosynthetic subunits. Up to now, the flu mutant was the only biological system adopted to define the regulation of gene expression by 1O2. In this work, we propose the use of mutants accumulating 1O2 by mechanisms different from those activated in flu to better identify ROS signalling. Conclusions We propose that the lack of zeaxanthin and lutein leads to 1O2 accumulation and this represents a signalling pathway in the early stages of stress acclimation, beside the response to ADP/ATP ratio and to the redox state of both plastoquinone pool. Chloroplasts respond to 1O2 accumulation by undergoing a significant change in composition and function towards a fast acclimatory response. The physiological implications of this signalling specificity are discussed. PMID:21481232

Electron transport chain-dependent and -independent mechanisms of mitochondrial H2O2 emission during long-chain fatty acid oxidation.

PubMed

Seifert, Erin L; Estey, Carmen; Xuan, Jian Y; Harper, Mary-Ellen

2010-02-19

Oxidative stress in skeletal muscle is a hallmark of various pathophysiologic states that also feature increased reliance on long-chain fatty acid (LCFA) substrate, such as insulin resistance and exercise. However, little is known about the mechanistic basis of the LCFA-induced reactive oxygen species (ROS) burden in intact mitochondria, and elucidation of this mechanistic basis was the goal of this study. Specific aims were to determine the extent to which LCFA catabolism is associated with ROS production and to gain mechanistic insights into the associated ROS production. Because intermediates and by-products of LCFA catabolism may interfere with antioxidant mechanisms, we predicted that ROS formation during LCFA catabolism reflects a complex process involving multiple sites of ROS production as well as modified mitochondrial function. Thus, we utilized several complementary approaches to probe the underlying mechanism(s). Using skeletal muscle mitochondria, our findings indicate that even a low supply of LCFA is associated with ROS formation in excess of that generated by NADH-linked substrates. Moreover, ROS production was evident across the physiologic range of membrane potential and was relatively insensitive to membrane potential changes. Determinations of topology and membrane potential as well as use of inhibitors revealed complex III and the electron transfer flavoprotein (ETF) and ETF-oxidoreductase, as likely sites of ROS production. Finally, ROS production was sensitive to matrix levels of LCFA catabolic intermediates, indicating that mitochondrial export of LCFA catabolic intermediates can play a role in determining ROS levels.

Osmoregulation and antioxidant production in maize under combined cadmium and arsenic stress.

PubMed

Anjum, Shakeel Ahmad; Tanveer, Mohsin; Hussain, Saddam; Shahzad, Babar; Ashraf, Umair; Fahad, Shah; Hassan, Waseem; Jan, Saad; Khan, Imran; Saleem, Muhammad Farrukh; Bajwa, Ali Ahsan; Wang, Longchang; Mahmood, Aqib; Samad, Rana Abdul; Tung, Shahbaz Atta

2016-06-01

An investigation was carried out to examine the combined and individual effects of cadmium (Cd) and arsenic (As) stress on osmolyte accumulation, antioxidant activities, and reactive oxygen species (ROS) production at different growth stages (45, 60, 75, 90 days after sowing (DAS)) of two maize cultivars viz., Dong Dan 80 and Run Nong 35. The Cd (100 μM) and As (200 μM) were applied separately as well as in combination (Cd + As) at 30 DAS. Results revealed pronounced variations in the behavior of antioxidants, osmolytes, and ROS in both maize cultivars under the influence of Cd and As stress. Activities of enzymatic (SOD, POD, CAT and APX, GPX, GR) and non-enzymatic (GSH and AsA) antioxidants, generation of ROS, and accumulation of osmolytes were enhanced with the passage of time; therefore, the maximum values for these attributes were observed at 90 DAS for both cultivars. Exposure of plants to Cd or As stress considerably enhanced the antioxidant activities, ROS, and osmolyte accumulation compared with control, while combined application of Cd + As was more devastating in reducing plant biomass of both maize cultivars. Among cultivars, Dong Dan 80 was better able to negate the heavy metal-induced oxidative damage, which was associated with higher antioxidant activities, greater osmolytes accumulation, and lower ROS production in this cultivar.

Targeted Modification of Mitochondrial ROS Production Converts High Glucose-Induced Cytotoxicity to Cytoprotection: Effects on Anesthetic Preconditioning.

PubMed

Sedlic, Filip; Muravyeva, Maria Y; Sepac, Ana; Sedlic, Marija; Williams, Anna Marie; Yang, Meiying; Bai, Xiaowen; Bosnjak, Zeljko J

2017-01-01

Contradictory reports on the effects of diabetes and hyperglycemia on myocardial infarction range from cytotoxicity to cytoprotection. The study was designed to investigate acute effects of high glucose-driven changes in mitochondrial metabolism and osmolarity on adaptive mechanisms and resistance to oxidative stress of isolated rat cardiomyocytes. We examined the effects of high glucose on several parameters of mitochondrial bioenergetics, including changes in oxygen consumption, mitochondrial membrane potential, and NAD(P)H fluorometry. Effects of high glucose on the endogenous cytoprotective mechanisms elicited by anesthetic preconditioning (APC) and the mediators of cell injury were also tested. These experiments included real-time measurements of reactive oxygen species (ROS) production and mitochondrial permeability transition pore (mPTP) opening in single cells by laser scanning fluorescence confocal microscopy, and cell survival assay. High glucose rapidly enhanced mitochondrial energy metabolism, observed by increase in NAD(P)H fluorescence intensity, oxygen consumption, and mitochondrial membrane potential. This substantially elevated production of ROS, accelerated opening of the mPTP, and decreased survival of cells exposed to oxidative stress. Abrogation of high glucose-induced mitochondrial hyperpolarization with 2,4 dinitrophenol (DNP) significantly, but not completely, attenuated ROS production to a level similar to hyperosmotic mannitol control. DNP treatment reversed high glucose-induced cytotoxicity to cytoprotection. Hyperosmotic mannitol treatment also induced cytoprotection. High glucose abrogated APC-induced mitochondrial depolarization, delay in mPTP opening and cytoprotection. In conclusion, high glucose-induced mitochondrial hyperpolarization abolishes APC and augments cell injury. Attenuation of high glucose-induced ROS production by eliminating mitochondrial hyperpolarization protects cardiomyocytes. J. Cell. Physiol. 232: 216-224, 2017. © 2016 Wiley Periodicals, Inc. © 2016 Wiley Periodicals, Inc.

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.

Hydrogen sulfide replacement therapy protects the vascular endothelium in hyperglycemia by preserving mitochondrial function.

PubMed

Suzuki, Kunihiro; Olah, Gabor; Modis, Katalin; Coletta, Ciro; Kulp, Gabriella; Gerö, Domokos; Szoleczky, Petra; Chang, Tuanjie; Zhou, Zongmin; Wu, Lingyun; Wang, Rui; Papapetropoulos, Andreas; Szabo, Csaba

2011-08-16

The goal of the present studies was to investigate the role of changes in hydrogen sulfide (H(2)S) homeostasis in the pathogenesis of hyperglycemic endothelial dysfunction. Exposure of bEnd3 microvascular endothelial cells to elevated extracellular glucose (in vitro "hyperglycemia") induced the mitochondrial formation of reactive oxygen species (ROS), which resulted in an increased consumption of endogenous and exogenous H(2)S. Replacement of H(2)S or overexpression of the H(2)S-producing enzyme cystathionine-γ-lyase (CSE) attenuated the hyperglycemia-induced enhancement of ROS formation, attenuated nuclear DNA injury, reduced the activation of the nuclear enzyme poly(ADP-ribose) polymerase, and improved cellular viability. In vitro hyperglycemia resulted in a switch from oxidative phosphorylation to glycolysis, an effect that was partially corrected by H(2)S supplementation. Exposure of isolated vascular rings to high glucose in vitro induced an impairment of endothelium-dependent relaxations, which was prevented by CSE overexpression or H(2)S supplementation. siRNA silencing of CSE exacerbated ROS production in hyperglycemic endothelial cells. Vascular rings from CSE(-/-) mice exhibited an accelerated impairment of endothelium-dependent relaxations in response to in vitro hyperglycemia, compared with wild-type controls. Streptozotocin-induced diabetes in rats resulted in a decrease in the circulating level of H(2)S; replacement of H(2)S protected from the development of endothelial dysfunction ex vivo. In conclusion, endogenously produced H(2)S protects against the development of hyperglycemia-induced endothelial dysfunction. We hypothesize that, in hyperglycemic endothelial cells, mitochondrial ROS production and increased H(2)S catabolism form a positive feed-forward cycle. H(2)S replacement protects against these alterations, resulting in reduced ROS formation, improved endothelial metabolic state, and maintenance of normal endothelial function.

Effect of residual oil saturation on hydrodynamic properties of porous media

NASA Astrophysics Data System (ADS)

Zhang, Junjie; Zheng, Xilai; Chen, Lei; Sun, Yunwei

2014-07-01

To understand the effect of residual oil on hydraulic properties and solute dispersive behavior of porous media, miscible displacement column experiments were conducted using two petroleum products (diesel and engine oil) and a sandy soil. The effective water permeability, effective water-filled porosity, and dispersivity were investigated in two-fluid systems of water and oil as a function of residual oil saturation (ROS). At the end of each experiment, the distribution of ending ROS along the sand column was determined by the method of petroleum ether extraction-ultraviolet spectrophotometry. Darcy’s Law was used to determine permeability, while breakthrough curves (BTCs) of a tracer, Cl-, were used to calibrate effective porosity and dispersivity. The experimental results indicate that the maximum saturated zone residual saturation of diesel and engine oil in this study are 16.0% and 45.7%, respectively. Cl- is found to have no sorption on the solid matrix. Generated BTCs are sigmoid in shape with no evidence of tailing. The effective porosity of sand is inversely proportional to ROS. For the same level of ROS, the magnitude of reduction in effective porosity by diesel is close to that by engine oil. The relative permeability of sand to water saturation decreases with increasing amount of trapped oil, and the slope of the relative permeability-saturation curve for water is larger at higher water saturations, indicating that oil first occupies larger pores, which have the most contribution to the conductivity of the water. In addition, the reduction rate of relative permeability by diesel is greater than that by engine oil. The dispersivity increases with increasing ROS, suggesting that the blockage of pore spaces by immobile oil globules may enhance local velocity variations and increase the tortuosity of aqueous-phase flow paths.

Variation in levels of reactive oxygen species is explained by maternal identity, sex and body-size-corrected clutch size in a lizard

NASA Astrophysics Data System (ADS)

Olsson, Mats; Wilson, Mark; Uller, Tobias; Mott, Beth; Isaksson, Caroline

2009-01-01

Many organisms show differences between males and females in growth rate and crucial life history parameters, such as longevity. Considering this, we may expect levels of toxic metabolic by-products of the respiratory chain, such as reactive oxygen species (ROS), to vary with age and sex. Here, we analyse ROS levels in female Australian painted dragon lizards ( Ctenophorus pictus) and their offspring using fluorescent probes and flow cytometry. Basal level of four ROS species (singlet oxygen, peroxynitrite, superoxide and H2O2) measured with a combined marker, and superoxide measured specifically, varied significantly among families but not between the sexes. When blood cells from offspring were chemically encouraged to accelerate the electron transport chain by mitochondrial uncoupling, net superoxide levels were three times higher in daughters than sons (resulting in levels outside of the normal ROS range) and varied among mothers depending on offspring sex (significant interaction between maternal identity and offspring sex). In offspring, there were depressive effects on ROS of size-controlled relative clutch size, which relies directly on circulating levels of vitellogenin, a confirmed antioxidant in some species. Thus, levels of reactive oxygen species varies among females, offspring and in relation to reproductive investment in a manner that makes its regulatory processes likely targets of selection.

Reactive Oxygen Species Induce Antiviral Innate Immune Response through IFN-λ Regulation in Human Nasal Epithelial Cells

PubMed Central

Kim, Hyun Jik; Kim, Chang-Hoon; Ryu, Ji-Hwan; Kim, Min-Ji; Park, Chong Yoon; Lee, Jae Myun; Holtzman, Michael J.

2013-01-01

This study sought to explore the role of the IFN-related innate immune responses (IFN-β and IFN-λ) and of reactive oxygen species (ROS) after influenza A virus (IAV) infection for antiviral innate immune activity in normal human nasal epithelial (NHNE) cells that are highly exposed to IAV. Passage-2 NHNE cells were inoculated with the IAV WSN/33 for 1, 2, and 3 days to assess the capacity of IFN and the relationship between ROS generation and IFN-λ secretion for controlling IAV infection. Viral titers and IAV mRNA levels increased after infection. In concert with viral titers, we found that the generation of IFNs, such as IFN-β, IFN-λ1, and IFN-λ2/3, was induced after IAV infection until 3 days after infection. The induction of IFN-λ gene expression and protein secretion may be predominant after IAV infection. Similarly, we observed that intracellular ROS generation increased 60 minutes after IAV infection. Viral titers and mRNA levels of IAV were significantly higher in cases with scavenging ROS, in cases with an induced IFN-λ mRNA level, or where the secreted protein concentration of IFN-λ was attenuated after the suppression of ROS generation. Both mitochondrial and dual oxidase (Doux)2-generated ROS were correlated with IAV mRNA and viral titers. The inhibition of mitochondrial ROS generation and the knockdown of Duox2 gene expression highly increased IAV viral titers and decreased IFN-λ secretion. Our findings suggest that the production of ROS may be responsible for IFN-λ secretion to control IAV infection. Both mitochondria and Duox2 are possible sources of ROS generation, which is required to initiate an innate immune response in NHNE cells. PMID:23786562

Enhanced reactive oxygen species through direct copper sulfide nanoparticle-doxorubicin complexation

NASA Astrophysics Data System (ADS)

Li, Yajuan; Cupo, Michela; Guo, Liangran; Scott, Julie; Chen, Yi-Tzai; Yan, Bingfang; Lu, Wei

2017-12-01

CuS-based nanostructures loading the chemotherapeutic agent doxorubicin (DOX) exerted excellent cancer photothermal chemotherapy under multi-external stimuli. The DOX loading was generally designed through electrostatic interaction or chemical linkers. However, the interaction between DOX molecules and CuS nanoparticles has not been investigated. In this work, we use PEGylated hollow copper sulfide nanoparticles (HCuSNPs) to directly load DOX through the DOX/Cu2+ chelation process. Distinctively, the synthesized PEG-HCuSNPs-DOX release the DOX/Cu2+ complexes into surrounding environment, which generate significant reactive oxygen species (ROS) in a controlled manner by near-infrared laser. The CuS nanoparticle-mediated photothermal ablation facilitates the ROS-induced cancer cell killing effect. Our current work reveals a DOX/Cu2+-mediated ROS-enhanced cell-killing effect in addition to conventional photothermal chemotherapy through the direct CuS nanoparticle-DOX complexation.

Prostaglandin E2 is critical for the development of niacin-deficiency-induced photosensitivity via ROS production

NASA Astrophysics Data System (ADS)

Sugita, Kazunari; Ikenouchi-Sugita, Atsuko; Nakayama, Yasuko; Yoshioka, Haruna; Nomura, Takashi; Sakabe, Jun-Ichi; Nakahigashi, Kyoko; Kuroda, Etsushi; Uematsu, Satoshi; Nakamura, Jun; Akira, Shizuo; Nakamura, Motonobu; Narumiya, Shuh; Miyachi, Yoshiki; Tokura, Yoshiki; Kabashima, Kenji

2013-10-01

Pellagra is a photosensitivity syndrome characterized by three ``D's'': diarrhea, dermatitis, and dementia as a result of niacin deficiency. However, the molecular mechanisms of photosensitivity dermatitis, the hallmark abnormality of this syndrome, remain unclear. We prepared niacin deficient mice in order to develop a murine model of pellagra. Niacin deficiency induced photosensitivity and severe diarrhea with weight loss. In addition, niacin deficient mice exhibited elevated expressions of COX-2 and PGE syntheses (Ptges) mRNA. Consistently, photosensitivity was alleviated by a COX inhibitor, deficiency of Ptges, or blockade of EP4 receptor signaling. Moreover, enhanced PGE2 production in niacin deficiency was mediated via ROS production in keratinocytes. In line with the above murine findings, human skin lesions of pellagra patients confirmed the enhanced expression of Ptges. Niacin deficiency-induced photosensitivity was mediated through EP4 signaling in response to increased PGE2 production via induction of ROS formation.

ROS, Cell Senescence, and Novel Molecular Mechanisms in Aging and Age-Related Diseases

PubMed Central

Davalli, Pierpaola; Mitic, Tijana; Caporali, Andrea; Lauriola, Angela; D'Arca, Domenico

2016-01-01

The aging process worsens the human body functions at multiple levels, thus causing its gradual decrease to resist stress, damage, and disease. Besides changes in gene expression and metabolic control, the aging rate has been associated with the production of high levels of Reactive Oxygen Species (ROS) and/or Reactive Nitrosative Species (RNS). Specific increases of ROS level have been demonstrated as potentially critical for induction and maintenance of cell senescence process. Causal connection between ROS, aging, age-related pathologies, and cell senescence is studied intensely. Senescent cells have been proposed as a target for interventions to delay the aging and its related diseases or to improve the diseases treatment. Therapeutic interventions towards senescent cells might allow restoring the health and curing the diseases that share basal processes, rather than curing each disease in separate and symptomatic way. Here, we review observations on ROS ability of inducing cell senescence through novel mechanisms that underpin aging processes. Particular emphasis is addressed to the novel mechanisms of ROS involvement in epigenetic regulation of cell senescence and aging, with the aim to individuate specific pathways, which might promote healthy lifespan and improve aging. PMID:27247702

Nitric Oxide Enhances Desiccation Tolerance of Recalcitrant Antiaris toxicaria Seeds via Protein S-Nitrosylation and Carbonylation

PubMed Central

Bai, Xuegui; Yang, Liming; Tian, Meihua; Chen, Jinhui; Shi, Jisen; Yang, Yongping; Hu, Xiangyang

2011-01-01

The viability of recalcitrant seeds is lost following stress from either drying or freezing. Reactive oxygen species (ROS) resulting from uncontrolled metabolic activity are likely responsible for seed sensitivity to drying. Nitric oxide (NO) and the ascorbate-glutathione cycle can be used for the detoxification of ROS, but their roles in the seed response to desiccation remain poorly understood. Here, we report that desiccation induces rapid accumulation of H2O2, which blocks recalcitrant Antiaris toxicaria seed germination; however, pretreatment with NO increases the activity of antioxidant ascorbate-glutathione pathway enzymes and metabolites, diminishes H2O2 production and assuages the inhibitory effects of desiccation on seed germination. Desiccation increases the protein carbonylation levels and reduces protein S-nitrosylation of these antioxidant enzymes; these effects can be reversed with NO treatment. Antioxidant protein S-nitrosylation levels can be further increased by the application of S-nitrosoglutathione reductase inhibitors, which further enhances NO-induced seed germination rates after desiccation and reduces desiccation-induced H2O2 accumulation. These findings suggest that NO reinforces recalcitrant seed desiccation tolerance by regulating antioxidant enzyme activities to stabilize H2O2 accumulation at an appropriate concentration. During this process, protein carbonylation and S-nitrosylation patterns are used as a specific molecular switch to control antioxidant enzyme activities. PMID:21674063

Limiting prolonged inflammation during proliferation and remodeling phases of wound healing in streptozotocin-induced diabetic rats supplemented with camel undenatured whey protein.

PubMed

Ebaid, Hossam; Ahmed, Osama M; Mahmoud, Ayman M; Ahmed, Rasha R

2013-07-25

Impaired diabetic wound healing occurs as a consequence of excessive reactive oxygen species (ROS) and inflammatory cytokine production. We previously found that whey protein (WP) was able to normally regulate the ROS and inflammatory cytokines during the inflammatory phase (first day) in streptozotocin (STZ)-diabetic wound healing. This study was designed to assess the effect of WP on metabolic status, the inflammation and anti-inflammation response, oxidative stress and the antioxidant defense system during different phases of the wound healing process in diabetic rats. WP at a dosage of 100 mg/kg of body weight, dissolved in 1% CMC, was orally administered daily to wounded normal (non-diabetic) and STZ-induced diabetic rats for 8 days starting from the 1st day after wounding. The data revealed that WP enhanced wound closure and was associated with an increase in serum insulin levels in diabetic rats and an alleviation of hyperglycemic and hyperlipidemic states in diabetic animals. The increase in insulin levels as a result of WP administration is associated with a marked multiplication of β-cells in the core of islets of Langerhans. WP induced a reduction in serum TNF-α, IL-1β and IL-6 levels and an increase in IL-10 levels, especially on the 4th day after wounding and treatment. WP also suppressed hepatic lipid peroxidation and stimulated the antioxidant defense system by increasing the level of glutathione and the activity of glutathione-S-transferase, glutathione peroxidase and superoxide dismutase (SOD) in wounded diabetic rats. WP was observed to enhance wound closure by improving the diabetic condition, limiting prolonged inflammation, suppressing oxidative stress and elevating the antioxidant defense system in diabetic rats.

Limiting prolonged inflammation during proliferation and remodeling phases of wound healing in streptozotocin-induced diabetic rats supplemented with camel undenatured whey protein

PubMed Central

2013-01-01

Background Impaired diabetic wound healing occurs as a consequence of excessive reactive oxygen species (ROS) and inflammatory cytokine production. We previously found that whey protein (WP) was able to normally regulate the ROS and inflammatory cytokines during the inflammatory phase (first day) in streptozotocin (STZ)-diabetic wound healing. This study was designed to assess the effect of WP on metabolic status, the inflammation and anti-inflammation response, oxidative stress and the antioxidant defense system during different phases of the wound healing process in diabetic rats. WP at a dosage of 100 mg/kg of body weight, dissolved in 1% CMC, was orally administered daily to wounded normal (non-diabetic) and STZ-induced diabetic rats for 8 days starting from the 1st day after wounding. Results The data revealed that WP enhanced wound closure and was associated with an increase in serum insulin levels in diabetic rats and an alleviation of hyperglycemic and hyperlipidemic states in diabetic animals. The increase in insulin levels as a result of WP administration is associated with a marked multiplication of β-cells in the core of islets of Langerhans. WP induced a reduction in serum TNF-α, IL-1β and IL-6 levels and an increase in IL-10 levels, especially on the 4th day after wounding and treatment. WP also suppressed hepatic lipid peroxidation and stimulated the antioxidant defense system by increasing the level of glutathione and the activity of glutathione-S-transferase, glutathione peroxidase and superoxide dismutase (SOD) in wounded diabetic rats. Conclusions WP was observed to enhance wound closure by improving the diabetic condition, limiting prolonged inflammation, suppressing oxidative stress and elevating the antioxidant defense system in diabetic rats. PMID:23883360

Bartter/Gitelman syndromes as a model to study systemic oxidative stress in humans.

PubMed

Maiolino, Giuseppe; Azzolini, Matteo; Rossi, Gian Paolo; Davis, Paul A; Calò, Lorenzo A

2015-11-01

Reactive oxygen species (ROS) are intermediates in reduction-oxidation reactions that begin with the addition of one electron to molecular oxygen, generating the primary ROS superoxide, which in turn interacts with other molecules to produce secondary ROS, such as hydrogen peroxide, hydroxyl radical, and peroxynitrite. ROS are continuously produced during metabolic processes and are deemed to play an important role in cardiovascular diseases, namely, myocardial hypertrophy and fibrosis and atherosclerosis, via oxidative damage of lipids, proteins, and deoxyribonucleic acid. Angiotensin II (Ang II) is a potent vasoactive agent that also exerts mitogenic, proinflammatory, and profibrotic effects through several signaling pathways, in part involving ROS, particularly superoxide and hydrogen peroxide. Moreover, Ang II stimulates NADPH oxidases, leading to higher ROS generation and oxidative stress. Bartter/Gitelman syndrome patients, despite elevated plasma renin activity, Ang II, and aldosterone levels, exhibit reduced peripheral resistance, normal/low blood pressure, and blunted pressor effect of vasoconstrictors. In addition, notwithstanding the activation of the renin-angiotensin system and the increased plasma levels of Ang II, these patients display decreased production of ROS, reduced oxidative stress, and increased antioxidant defenses. In fact, Bartter/Gitelman syndrome patients are characterized by reduced levels of p22(phox) gene expression and undetectable plasma peroxynitrite levels, while showing increased plasma antioxidant power and expression of antioxidant enzymes, such as heme oxygenase-1. In conclusion, multifarious data suggest that Bartter and Gitelman syndrome patients are a model of low oxidative stress and high antioxidant defenses. The contribution offered by the study of these syndromes in elucidating the molecular mechanisms underlying this favorable status could offer chances for new therapeutic targets in disease characterized by high levels of reactive oxygen species. Copyright © 2015 Elsevier Inc. All rights reserved.

Agaricus blazei extract attenuates rotenone-induced apoptosis through its mitochondrial protective and antioxidant properties in SH-SY5Y neuroblastoma cells.

PubMed

Venkatesh Gobi, Veerappan; Rajasankar, Srinivasagam; Ramkumar, Muthu; Dhanalakshmi, Chinnasamy; Manivasagam, Thamilarasan; Justin Thenmozhi, Arokiasamy; Essa, Musthafa Mohamed; Chidambaram, Ranganathan

2018-02-01

The present study was aimed to find out the effect of Agaricus blazei mushroom extract against rotenone-induced cellular model. SH-SY5Y neuroblastoma cells are divided into four experimental groups (control, rotenone (100 nM), A. blazei (5 μg/ml) + rotenone (100 nM), and A. blazei alone treated) based on MTT assay, cells were allowed to measure the ROS, TBARS levels, and antioxidants activities. Finally, mitochondrial transmembrane potential (MMP) and expressions of apoptotic proteins were also analyzed. Pre-treatment with A. blazei significantly enhanced cell viability, attenuated rotenone-induced ROS, MMP, and apoptosis. Our results indicated that anti-apoptotic properties of this natural compound due to its antioxidant and mitochondrial protective function protect rotenone-induced cytotoxicity. Therefore, it may be concluded that A. blazei can be further developed as a promising drug for the treatment of Parkinson's disease (PD).

Effect of Rhizobium and arbuscular mycorrhizal fungi inoculation on electrolyte leakage in Phaseolus vulgaris roots overexpressing RbohB.

PubMed

Arthikala, Manoj-Kumar; Nava, Noreide; Quinto, Carmen

2015-01-01

Respiratory oxidative burst homolog (RBOH)-mediated reactive oxygen species (ROS) regulate a wide range of biological functions in plants. They play a critical role in the symbiosis between legumes and nitrogen-fixing bacteria or arbuscular mycorrhizal (AM) fungi. For instance, overexpression of PvRbohB enhances nodule numbers, but reduces mycorrhizal colonization in Phaseolus vulgaris hairy roots and downregulation has the opposite effect. In the present study, we assessed the effect of both rhizobia and AM fungi on electrolyte leakage in transgenic P. vulgaris roots overexpressing (OE) PvRbohB. We demonstrate that elevated levels of electrolyte leakage in uninoculated PvRbohB-OE transgenic roots were alleviated by either Rhizobium or AM fungi symbiosis, with the latter interaction having the greater effect. These results suggest that symbiont colonization reduces ROS elevated electrolyte leakage in P. vulgaris root cells.

Thyroid hormone-induced oxidative stress.

PubMed

Venditti, P; Di Meo, S

2006-02-01

Hypermetabolic state in hyperthyroidism is associated with tissue oxidative injury. Available data indicate that hyperthyroid tissues exhibit an increased ROS and RNS production. The increased mitochondrial ROS generation is a side effect of the enhanced level of electron carriers, by which hyperthyroid tissues increase their metabolic capacity. Investigations of antioxidant defence system have returned controversial results. Moreover, other thyroid hormone-linked biochemical changes increase tissue susceptibility to oxidative challenge, which exacerbates the injury and dysfunction they suffer under stressful conditions. Mitochondria, as a primary target for oxidative stress, might account for hyperthyroidism linked tissue dysfunction. This is consistent with the inverse relationship found between functional recovery of ischemic hyperthyroid hearts and mitochondrial oxidative damage and respiration impairment. However, thyroid hormone-activated mitochondrial mechanisms provide protection against excessive tissue dysfunction, including increased expression of uncoupling proteins, proteolytic enzymes and transcriptional coactivator PGC-1, and stimulate opening of permeability transition pores.

Enhanced reactive oxygen species overexpression by CuO nanoparticles in poorly differentiated hepatocellular carcinoma cells

NASA Astrophysics Data System (ADS)

Kung, Mei-Lang; Hsieh, Shu-Ling; Wu, Chih-Chung; Chu, Tian-Huei; Lin, Yu-Chun; Yeh, Bi-Wen; Hsieh, Shuchen

2015-01-01

Copper oxide nanoparticles (CuO NPs) are known to exhibit toxic effects on a variety of cell types and organs. To determine the oxidative impact of CuO NPs on hepatocellular carcinoma (HCC) cells, well-differentiated (HepG2) and poorly differentiated (SK-Hep-1) cells were exposed to CuO NPs. Cell viability assay showed that the median inhibition concentration (IC50) for SK-Hep-1 and HepG2 cells was 25 μg ml-1 and 85 μg ml-1, respectively. Cellular fluorescence intensity using DCFH-DA staining analysis revealed significant intracellular reactive oxygen species (ROS) generation of up to 242% in SK-Hep-1 cells, compared with 86% in HepG2 cells. HPLC analysis demonstrated that a CuO NP treatment caused cellular GSH depletion of 58% and a GSH/GSSG ratio decrease to ~0.1 in SK-Hep-1 cells. The oxidative stress caused by enhanced superoxide anion production was observed in both HepG2 (146%) and SK-Hep-1 (192%) cells. The Griess assay verified that CuO NPs induced NO production (170%) in SK-Hep-1 cells. Comet assay and western blot further demonstrated that CuO NPs induced severe DNA strand breakage (70%) in SK-Hep-1 cells and caused DNA damage via increased γ-H2AX levels. These results suggest that well-differentiated HepG2 cells possess a robust antioxidant defense system against CuO NP-induced ROS stress and exhibit more tolerance to oxidative stress. Conversely, poorly differentiated SK-Hep-1 cells exhibited a deregulated antioxidant defense system that allowed accumulation of CuO NP-induced ROS and resulted in severe cytotoxicity.Copper oxide nanoparticles (CuO NPs) are known to exhibit toxic effects on a variety of cell types and organs. To determine the oxidative impact of CuO NPs on hepatocellular carcinoma (HCC) cells, well-differentiated (HepG2) and poorly differentiated (SK-Hep-1) cells were exposed to CuO NPs. Cell viability assay showed that the median inhibition concentration (IC50) for SK-Hep-1 and HepG2 cells was 25 μg ml-1 and 85 μg ml-1, respectively. Cellular fluorescence intensity using DCFH-DA staining analysis revealed significant intracellular reactive oxygen species (ROS) generation of up to 242% in SK-Hep-1 cells, compared with 86% in HepG2 cells. HPLC analysis demonstrated that a CuO NP treatment caused cellular GSH depletion of 58% and a GSH/GSSG ratio decrease to ~0.1 in SK-Hep-1 cells. The oxidative stress caused by enhanced superoxide anion production was observed in both HepG2 (146%) and SK-Hep-1 (192%) cells. The Griess assay verified that CuO NPs induced NO production (170%) in SK-Hep-1 cells. Comet assay and western blot further demonstrated that CuO NPs induced severe DNA strand breakage (70%) in SK-Hep-1 cells and caused DNA damage via increased γ-H2AX levels. These results suggest that well-differentiated HepG2 cells possess a robust antioxidant defense system against CuO NP-induced ROS stress and exhibit more tolerance to oxidative stress. Conversely, poorly differentiated SK-Hep-1 cells exhibited a deregulated antioxidant defense system that allowed accumulation of CuO NP-induced ROS and resulted in severe cytotoxicity. Electronic supplementary information (ESI) available. See DOI: 10.1039/c4nr05843g

Are Sunflower chlorotic mottle virus infection symptoms modulated by early increases in leaf sugar concentration?

PubMed

Rodríguez, Marianela; Taleisnik, Edith; Lenardon, Sergio; Lascano, Ramiro

2010-09-15

Symptom development in a susceptible sunflower line inoculated with Sunflower chlorotic mottle virus (SuCMoV) was followed in the second pair of leaves at different post-inoculation times: before symptom expression (BS), at early (ES) and late (LS) symptom expression. Sugar and starch increases and photoinhibition were observed as early effects BS, and were maintained or enhanced later on, however, chlorophyll loss was detected only at LS. Photoinhibition correlated with a drastic decrease in D1 protein level. The progress of infection was accompanied by decreasing levels of apoplastic reactive oxygen species (ROS). In infected leaves, higher antioxidant enzyme activities (superoxide dismutase, SOD; ascorbate peroxidase, APX; glutathione reductase, GR) were observed from BS. The purpose of this work was to evaluate whether the early increases in carbohydrate accumulation may participate in SuCMoV symptom expression. Similar effects on photoinhibition, apoplastic ROS generation and antioxidant activity were generated when healthy leaves were treated with sugars. These results suggest that photoinhibitory processes and lower apoplastic superoxide levels induced by SuCMoV infection may be modulated by sugar increases. Copyright 2010 Elsevier GmbH. All rights reserved.

Protective role of cytochrome P450 1A1 (CYP1A1) against benzo[a]pyrene-induced toxicity in mouse aorta.

PubMed

Uno, Shigeyuki; Sakurai, Kenichi; Nebert, Daniel W; Makishima, Makoto

2014-02-28

Benzo[a]pyrene (BaP) is an environmental pollutant produced by combustive processes, such as cigarette smoke and coke ovens, and is implicated in the pathogenesis of atherosclerosis. Cytochrome P450 1A1 (CYP1A1) plays a role in both metabolic activation and detoxication of BaP in a context-dependent manner. The role of CYP1A1 in BaP-induced toxicity in aorta remains unknown. First, we fed Apoe⁻/⁻ mice an atherogenic diet plus BaP and found that oral BaP-enhanced atherosclerosis is associated with increased reactive oxygen species (ROS) and inflammatory markers, such as plasma tumor necrosis factor levels and aortic mRNA expression of vascular endothelial growth factor A (Vegfa). We next examined the effect of an atherogenic diet plus BaP on ROS and inflammatory markers in Cyp1a1⁻/⁻ mice. Although this treatment was not sufficient to induce atherosclerotic lesions in Cyp1a1⁻/⁻ mice, plasma antioxidant levels were decreased in Cyp1a1⁻/⁻ mice even in the absence of BaP treatment. The atherogenic diet plus BaP effectively elevated plasma ROS levels and expression of atherosclerosis-related genes, specifically Vegfa, in Cyp1a1⁻/⁻ mice compared with wild-type mice. BaP treatment increased Vegfa mRNA levels in mouse embryonic fibroblasts from Cyp1a1⁻/⁻ mice but not from wild-type mice. BaP-induced DNA adduct formation was increased in the aorta of Cyp1a1⁻/⁻ mice, but not wild-type or Apoe⁻/⁻ mice, and the atherogenic diet decreased BaP-induced DNA adducts in Cyp1a1⁻/⁻ mice compared with mice on a control diet. These data suggest that ROS production contributes to BaP-exacerbated atherosclerosis and that CYP1A1 plays a protective role against oral BaP toxicity in aorta. Copyright © 2014 Elsevier Ireland Ltd. All rights reserved.

α-Lipoic Acid Inhibits Expression of IL-8 by Suppressing Activation of MAPK, Jak/Stat, and NF-κB in H. pylori-Infected Gastric Epithelial AGS Cells.

PubMed

Choi, Ji Hyun; Cho, Soon Ok; Kim, Hyeyoung

2016-01-01

The epithelial cytokine response, associated with reactive oxygen species (ROS), is important in Helicobacter pylori (H. pylori)-induced inflammation. H. pylori induces the production of ROS, which may be involved in the activation of mitogen-activated protein kinases (MAPK), janus kinase/signal transducers and activators of transcription (Jak/Stat), and oxidant-sensitive transcription factor, nuclear factor kappa-light-chain-enhancer of activated B cells (NF-κB), and thus, expression of interleukin-8 (IL-8) in gastric epithelial cells. α-lipoic acid, a naturally occurring thiol compound, is a potential antioxidant. It shows beneficial effects in treatment of oxidant-associated diseases including diabetes. The present study is purposed to investigate whether α-lipoic acid inhibits expression of inflammatory cytokine IL-8 by suppressing activation of MAPK, Jak/Stat, and NF-κB in H. pylori-infected gastric epithelial cells. Gastric epithelial AGS cells were pretreated with or without α-lipoic acid for 2 h and infected with H. pylori in a Korean isolate (HP99) at a ratio of 300:1. IL-8 mRNA expression was analyzed by RT-PCR analysis. IL-8 levels in the medium were determined by enzyme-linked immunosorbent assay. NF-κB-DNA binding activity was determined by electrophoretic mobility shift assay. Phospho-specific and total forms of MAPK and Jak/Stat were assessed by Western blot analysis. ROS levels were determined using dichlorofluorescein fluorescence. As a result, H. pylori induced increases in ROS levels, mRNA, and protein levels of IL-8, as well as the activation of MAPK [extracellular signal-regulated kinase 1/2 (ERK1/2), c-Jun NH2-terminal kinase 1/2 (JNK1/2), p38], Jak/Stat (Jak1/2, Stat3), and NF-κB in AGS cells, which was inhibited by α-lipoic acid. In conclusion, α-lipoic acid may be beneficial for prevention and/or treatment of H. pylori infection-associated gastric inflammation.

Evaluation of hyperpolarized [1-¹³C]-pyruvate by magnetic resonance to detect ionizing radiation effects in real time.

PubMed

Sandulache, Vlad C; Chen, Yunyun; Lee, Jaehyuk; Rubinstein, Ashley; Ramirez, Marc S; Skinner, Heath D; Walker, Christopher M; Williams, Michelle D; Tailor, Ramesh; Court, Laurence E; Bankson, James A; Lai, Stephen Y

2014-01-01

Ionizing radiation (IR) cytotoxicity is primarily mediated through reactive oxygen species (ROS). Since tumor cells neutralize ROS by utilizing reducing equivalents, we hypothesized that measurements of reducing potential using real-time hyperpolarized (HP) magnetic resonance spectroscopy (MRS) and spectroscopic imaging (MRSI) can serve as a surrogate marker of IR induced ROS. This hypothesis was tested in a pre-clinical model of anaplastic thyroid carcinoma (ATC), an aggressive head and neck malignancy. Human ATC cell lines were utilized to test IR effects on ROS and reducing potential in vitro and [1-¹³C] pyruvate HP-MRS/MRSI imaging of ATC orthotopic xenografts was used to study in vivo effects of IR. IR increased ATC intra-cellular ROS levels resulting in a corresponding decrease in reducing equivalent levels. Exogenous manipulation of cellular ROS and reducing equivalent levels altered ATC radiosensitivity in a predictable manner. Irradiation of ATC xenografts resulted in an acute drop in reducing potential measured using HP-MRS, reflecting the shunting of reducing equivalents towards ROS neutralization. Residual tumor tissue post irradiation demonstrated heterogeneous viability. We have adapted HP-MRS/MRSI to non-invasively measure IR mediated changes in tumor reducing potential in real time. Continued development of this technology could facilitate the development of an adaptive clinical algorithm based on real-time adjustments in IR dose and dose mapping.

The influence of blood glucose on neutrophil function in individuals without diabetes.

PubMed

Saito, Yuriko; Takahashi, Ippei; Iwane, Kaori; Okubo, Noriyuki; Nishimura, Miya; Matsuzaka, Masashi; Wada, Naoko; Miwa, Takashi; Umeda, Takashi; Nakaji, Shigeyuki

2013-01-01

We assessed the association of neutrophil function with glycated hemoglobin (HbA1c) levels in a Japanese general population. Participants were 809 males and females who were over 20 years old living in the Iwaki region in Aomori Prefecture located in northern Japan. Lifestyle parameters (smoking, alcohol consumption, and exercise habits), HbA1c and neutrophil function such as reactive oxygen species (ROS) production capability and phagocytic activity (PA) were measured. ROS production capability was measured before and after phagocytic stimulus to obtain basal ROS production and stimulated ROS production. Level of HbA1c had a positive correlation with basal ROS production (p=0.053), a negative correlation with stimulated ROS production (p=0.072) and PA (p=0.059) only in post-menopausal groups, and not in pre-menopausal groups. However, there were no correlations between levels of HbA1c and neutrophil functions in male. In conclusion, in the present study, despite the presence of diabetes, chronic hyperglycemia was found to cause an increase in daily basal ROS production of neutrophils, and increased susceptibility to infection caused by reduced neutrophilic reaction in females in their menopause. Therefore, from the oxidative point of view, strict glycemic control is necessary to prevent post-menopausal females from developing diabetic complications in spite of the presence of diabetes. Copyright © 2013 John Wiley & Sons, Ltd.

ROS and ROS-Mediated Cellular Signaling.

PubMed

Zhang, Jixiang; Wang, Xiaoli; Vikash, Vikash; Ye, Qing; Wu, Dandan; Liu, Yulan; Dong, Weiguo

2016-01-01

It has long been recognized that an increase of reactive oxygen species (ROS) can modify the cell-signaling proteins and have functional consequences, which successively mediate pathological processes such as atherosclerosis, diabetes, unchecked growth, neurodegeneration, inflammation, and aging. While numerous articles have demonstrated the impacts of ROS on various signaling pathways and clarify the mechanism of action of cell-signaling proteins, their influence on the level of intracellular ROS, and their complex interactions among multiple ROS associated signaling pathways, the systemic summary is necessary. In this review paper, we particularly focus on the pattern of the generation and homeostasis of intracellular ROS, the mechanisms and targets of ROS impacting on cell-signaling proteins (NF-κB, MAPKs, Keap1-Nrf2-ARE, and PI3K-Akt), ion channels and transporters (Ca(2+) and mPTP), and modifying protein kinase and Ubiquitination/Proteasome System.

ROS Hexapod

NASA Technical Reports Server (NTRS)

Davis, Kirsch; Bankieris, Derek

2016-01-01

As an intern project for NASA Johnson Space Center (JSC), my job was to familiarize myself and operate a Robotics Operating System (ROS). The project outcome converted existing software assets into ROS using nodes, enabling a robotic Hexapod to communicate to be functional and controlled by an existing PlayStation 3 (PS3) controller. Existing control algorithms and current libraries have no ROS capabilities within the Hexapod C++ source code when the internship started, but that has changed throughout my internship. Conversion of C++ codes to ROS enabled existing code to be compatible with ROS, and is now controlled using an existing PS3 controller. Furthermore, my job description was to design ROS messages and script programs that enabled assets to participate in the ROS ecosystem by subscribing and publishing messages. Software programming source code is written in directories using C++. Testing of software assets included compiling code within the Linux environment using a terminal. The terminal ran the code from a directory. Several problems occurred while compiling code and the code would not compile. So modifying code to where C++ can read the source code were made. Once the code was compiled and ran, the code was uploaded to Hexapod and then controlled by a PS3 controller. The project outcome has the Hexapod fully functional and compatible with ROS and operates using the PlayStation 3 controller. In addition, an open source software (IDE) Arduino board will be integrated into the ecosystem with designing circuitry on a breadboard to add additional behavior with push buttons, potentiometers and other simple elements in the electrical circuitry. Other projects with the Arduino will be a GPS module, digital clock that will run off 22 satellites to show accurate real time using a GPS signal and an internal patch antenna to communicate with satellites. In addition, this internship experience has led me to pursue myself to learn coding more efficiently and effectively to write, subscribe and publish my own source code in different programming languages. With some familiarity with software programming, it will enhance my skills in the electrical engineering field. In contrast, my experience here at JSC with the Simulation and Graphics Branch (ER7) has led me to take my coding skill to be more proficient to increase my knowledge in software programming, and also enhancing my skills in ROS. This knowledge will be taken back to my university to implement coding in a school project that will use source coding and ROS to work on the PR2 robot which is controlled by ROS software. My skills learned here will be used to integrate messages to subscribe and publish ROS messages to a PR2 robot. The PR2 robot will be controlled by an existing PS3 controller by changing C++ coding to subscribe and publish messages to ROS. Overall the skills that were obtained here will not be lost, but increased.

SU-G-TeP3-15: Radiation Dose Enhancement by Anatase TiO2NPs

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

Youkhana, E; Geso, M; Feltis, B

2016-06-15

Purpose: This work investigates radiation dose enhancement caused by TiO2 nanoparticles covering entire X-ray energy ranges used in radiation therapy. Methods: Anatase TiO2NPs crystal were synthesised and modified as hydrophilic and hydrophobic to disperse in culture-medium and halocarbons (PRESAGE chemical composition) respectively. TiO2NPs were characterised using TEM, XPS, XRD, TGA and FTIR. Various Concentrations have been utilised for determination of radiation-dose enhancement. This investigation is carried out in two ways; one using PRESAGE dosimeter/phantom and the other is radiobiological and based on in vitro study using two types of cell lines, Human Keratinocyte (HaCaT) and prostate cancer cell lines. Themore » x-ray used are both kilovoltage and megavoltage separately. The prepared PRESAGE dosimeters were scanned using optical CT scanner. Clonogenic and MTS assays were employed for cell cytotoxicity and viability measurements for determination of the levels of dose enhancement. Results: Significant about (50%, 45%) dose enhancement by TiO2-NPs for kV x-rays is measured in both ways (Presage and Cells study). Slightly more is detected with the cells. However, the dose enhancement with megavoltage beams was insignificant using Presage and under same conditions the cells survival curves indicates around 20% which is relatively high. This difference can only be attributed to some biochemical effects. Such as generation of reactive oxygen species (ROS), this can affect the cells while it can’t be detected by Presage. Elevation of hydroxyl radicals (•OH) of many orders is observed with the inclusion of TiO2-NPs in cells-medium. Conclusion: Dose enhancement inflicted by TiO2-NPs is proven to be significant with megavoltage beams and minimal with kV. The high dose enhancements obtained can be attributed to higher levels of ROS generated. Since MV beams are most commonly used, this research proves potential value for more efficient beam delivery. This has potential to be applied in future clinical radiotherapy applications The research is supported and funded by RMIT university-Melbourne/Australia.« less

Novel redox nanomedicine improves gene expression of polyion complex vector

NASA Astrophysics Data System (ADS)

Toh, Kazuko; Yoshitomi, Toru; Ikeda, Yutaka; Nagasaki, Yukio

2011-12-01

Gene therapy has generated worldwide attention as a new medical technology. While non-viral gene vectors are promising candidates as gene carriers, they have several issues such as toxicity and low transfection efficiency. We have hypothesized that the generation of reactive oxygen species (ROS) affects gene expression in polyplex supported gene delivery systems. The effect of ROS on the gene expression of polyplex was evaluated using a nitroxide radical-containing nanoparticle (RNP) as an ROS scavenger. When polyethyleneimine (PEI)/pGL3 or PEI alone was added to the HeLa cells, ROS levels increased significantly. In contrast, when (PEI)/pGL3 or PEI was added with RNP, the ROS levels were suppressed. The luciferase expression was increased by the treatment with RNP in a dose-dependent manner and the cellular uptake of pDNA was also increased. Inflammatory cytokines play an important role in ROS generation in vivo. In particular, tumor necrosis factor (TNF)-α caused intracellular ROS generation in HeLa cells and decreased gene expression. RNP treatment suppressed ROS production even in the presence of TNF-α and increased gene expression. This anti-inflammatory property of RNP suggests that it may be used as an effective adjuvant for non-viral gene delivery systems.

Activation of Aflatoxin Biosynthesis Alleviates Total ROS in Aspergillus parasiticus

PubMed Central

Kenne, Gabriel J.; Gummadidala, Phani M.; Omebeyinje, Mayomi H.; Mondal, Ananda M.; Bett, Dominic K.; McFadden, Sandra; Bromfield, Sydney; Banaszek, Nora; Velez-Martinez, Michelle; Mitra, Chandrani; Mikell, Isabelle; Chatterjee, Saurabh; Wee, Josephine; Chanda, Anindya

2018-01-01

An aspect of mycotoxin biosynthesis that remains unclear is its relationship with the cellular management of reactive oxygen species (ROS). Here we conduct a comparative study of the total ROS production in the wild-type strain (SU-1) of the plant pathogen and aflatoxin producer, Aspergillus parasiticus, and its mutant strain, AFS10, in which the aflatoxin biosynthesis pathway is blocked by disruption of its pathway regulator, aflR. We show that SU-1 demonstrates a significantly faster decrease in total ROS than AFS10 between 24 h to 48 h, a time window within which aflatoxin synthesis is activated and reaches peak levels in SU-1. The impact of aflatoxin synthesis in alleviation of ROS correlated well with the transcriptional activation of five superoxide dismutases (SOD), a group of enzymes that protect cells from elevated levels of a class of ROS, the superoxide radicals (O2−). Finally, we show that aflatoxin supplementation to AFS10 growth medium results in a significant reduction of total ROS only in 24 h cultures, without resulting in significant changes in SOD gene expression. Our findings show that the activation of aflatoxin biosynthesis in A. parasiticus alleviates ROS generation, which in turn, can be both aflR dependent and aflatoxin dependent. PMID:29382166

BMP2 induces PANC-1 cell invasion by MMP-2 overexpression through ROS and ERK.

PubMed

Liu, Jun; Ben, Qi-Wen; Yao, Wei-Yan; Zhang, Jian-Jun; Chen, Da-Fan; He, Xiang-Yi; Li, Lei; Yuan, Yao-Zong

2012-06-01

The emerging roles of bone morphogenetic proteins (BMPs) in the initiation and progression of multiple cancers have drawn great attention in cancer research. We hypothesized that BMP2 promotes cancer metastasis by modulating MMP-2 secretion and activity through intracellular ROS regulation and ERK activation in human pancreatic cancer. Our data show that stimulation of PANC-1 cells with BMP2 induced MMP-2 secretion and activation, associated with decreased E-cadherin expression, resulting in epithelial-to-mesenchymal transformation (EMT) and cell invasion. Blockade of ROS by the ROS scavenger, 2-MPG, abolished cell invasion, inhibited the EMT process and decreased MMP-2 expression, suggesting ROS accumulation caused an increase in MMP-2 expression in BMP2-stimulated PANC-1 cell invasion. Furthermore, treatment of PANC-1 cells with 2-MPG or ERK inhibitor PD98059 reduced the phosphorylation of ERK, resulting in attenuation of BMP2-induced cell invasion and MMP-2 activation. Taken together, these results suggest that BMP2 induces the cell invasion of PANC-1 cells by enhancing MMP-2 secretion and acting through ROS accumulation and ERK activation.

Dynamic activation of Src induced by low-power laser irradiation in living cells mediated by reactive oxygen species

NASA Astrophysics Data System (ADS)

Zhang, Juntao; Gao, Xuejuan; Xing, Da; Liu, Lei

2007-11-01

Low-power laser irradiation (LPLI) leads to photochemical reaction and then activates intracellular several signaling pathway. Reactive oxygen species (ROS) are considered to be the primary messengers produced by LPLI. Here, we studied the signaling pathway mediated by ROS upon the stimulation of LPLI. Src tyrosine kinases are well-known targets of ROS and can be activated by oxidative events. Using a Src reporter based on fluorescence resonance energy transfer (FRET) technique, we visualized the dynamic Src activation in Hela cells immediately after LPLI. Moreover, Src activity was enhanced by increasing the duration of LPLI. In addition, our results suggested that ROS were key mediators of Src activation, as ROS scavenger, vitamin C decreased and exogenous H IIO II increased the activity of Src. Meanwhile, Gö6983 loading did not block the effect of LPLI. CCK-8 experiments proved that cell vitality was prominently improved by LPLI with all the doses we applied in our experiments ranging from 3 to 25J/cm2. The results indicated that LPLI/ROS/Src pathway may be involved in the LPLI biostimulation effects.

Antioxidant dieckol downregulates the Rac1/ROS signaling pathway and inhibits Wiskott-Aldrich syndrome protein (WASP)-family verprolin-homologous protein 2 (WAVE2)-mediated invasive migration of B16 mouse melanoma cells.

PubMed

Park, Sun Joo; Kim, Yong Tae; Jeon, You Jin

2012-04-01

Reactive oxygen species (ROS) generation is linked to dynamic actin cytoskeleton reorganization, which is involved in tumor cell motility and metastasis. Thus, inhibition of ROS generation and actin polymerization in tumor cells may represent an effective anticancer strategy. However, the molecular basis of this signaling pathway is currently unknown. Here, we show that the Ecklonia cava-derived antioxidant dieckol downregulates the Rac1/ROS signaling pathway and inhibits Wiskott-Aldrich syndrome protein (WASP)-family verprolin-homologous protein 2 (WAVE2)-mediated invasive migration of B16 mouse melanoma cells. Steady-state intracellular ROS levels were higher in malignant B16F10 cells than in parental, nonmetastatic B16F0 cells. Elevation of ROS by H(2)O(2) treatment increased migration and invasion ability of B16F0 cells to level similar to that of B16F10 cells, suggesting that intracellular ROS signaling mediates the prometastatic properties of B16 mouse melanoma cells. ROS levels and the cell migration and invasion ability of B16 melanoma cells correlated with Rac1 activation and WAVE2 expression. Overexpression of dominant negative Rac1 and depletion of WAVE2 by siRNA suppressed H(2)O(2)-induced cell invasion of B16F0 and B16F10 cells. Similarly, dieckol attenuates the ROS-mediated Rac1 activation and WAVE2 expression, resulting in decreased migration and invasion of B16 melanoma cells. In addition, we found that dieckol decreases association between WAVE2 and NADPH oxidase subunit p47(phox). Therefore, this finding suggests that WAVE2 acts to couple intracellular Rac1/ROS signaling to the invasive migration of B16 melanoma cells, which is inhibited by dieckol.

Antioxidant Dieckol Downregulates the Rac1/ROS Signaling Pathway and Inhibits Wiskott-Aldrich Syndrome Protein (WASP)-Family Verprolin-Homologous Protein 2 (WAVE2)-Mediated Invasive Migration of B16 Mouse Melanoma Cells

PubMed Central

Park, Sun Joo; Kim, Yong Tae; Jeon, You Jin

2012-01-01

Reactive oxygen species (ROS) generation is linked to dynamic actin cytoskeleton reorganization, which is involved in tumor cell motility and metastasis. Thus, inhibition of ROS generation and actin polymerization in tumor cells may represent an effective anticancer strategy. However, the molecular basis of this signaling pathway is currently unknown. Here, we show that the Ecklonia cava-derived antioxidant dieckol downregulates the Rac1/ROS signaling pathway and inhibits Wiskott-Aldrich syndrome protein (WASP)-family verprolin-homologous protein 2 (WAVE2)-mediated invasive migration of B16 mouse melanoma cells. Steady-state intracellular ROS levels were higher in malignant B16F10 cells than in parental, nonmetastatic B16F0 cells. Elevation of ROS by H2O2 treatment increased migration and invasion ability of B16F0 cells to level similar to that of B16F10 cells, suggesting that intracellular ROS signaling mediates the prometastatic properties of B16 mouse melanoma cells. ROS levels and the cell migration and invasion ability of B16 melanoma cells correlated with Rac1 activation and WAVE2 expression. Overexpression of dominant negative Rac1 and depletion of WAVE2 by siRNA suppressed H2O2-induced cell invasion of B16F0 and B16F10 cells. Similarly, dieckol attenuates the ROS-mediated Rac1 activation and WAVE2 expression, resulting in decreased migration and invasion of B16 melanoma cells. In addition, we found that dieckol decreases association between WAVE2 and NADPH oxidase subunit p47phox. Therefore, this finding suggests that WAVE2 acts to couple intracellular Rac1/ROS signaling to the invasive migration of B16 melanoma cells, which is inhibited by dieckol. PMID:22441674

Utility of the nitroblue tetrazolium reduction test for assessment of reactive oxygen species production by seminal leukocytes and spermatozoa.

PubMed

Esfandiari, Navid; Sharma, Rakesh K; Saleh, Ramadan A; Thomas, Anthony J; Agarwal, Ashok

2003-01-01

The purpose of this study was to evaluate the ability of spermatozoa and leukocytes in semen to produce reactive oxygen species (ROS) by using nitroblue tetrazolium (NBT) staining and to examine the association between NBT staining and levels of ROS as measured by chemiluminescence. Twenty-one infertility patients (leukocytospermia; n = 8; nonleukocytospermia, n = 13) and 9 healthy donors were included. Standard semen analysis and density gradient centrifugation were performed to test NBT staining, ROS, and total antioxidant capacity. A ROS-total antioxidant capacity (ROS-TAC) score was calculated by using principal component analysis. In the leukocytospermic group, after separation on a density gradient, the percentage of NBT-positive staining was significantly higher in sperm suspensions contaminated with leukocytes (median [25th, 75th percentiles]; 70% [61%, 79%]) compared to the nonleukocytospermic group (14.5% [9%, 25.5%]; P =.03) and donors (7% [3%, 11%]; P =.02), respectively. A strong positive correlation was seen between levels of ROS in whole ejaculates and NBT-positive staining in leukocytes (r = 0.59; P <.0006) and in leukocyte fractions (r = 0.72; P <.0001) after density gradient separation. Similarly, ROS was positively correlated with excessive cytoplasmic retention in spermatozoa from whole ejaculates and abnormal spermatozoa after separation on density gradients (r = 0.72; P <.0001). The ROS-TAC score was inversely correlated with NBT staining in leukocytes in whole ejaculates (r = -0.960, P <.0007) and in both leukocyte fractions (r = -0.39; P <.04) and spermatozoa with cytoplasmic retention (r = -0.38; P <.04). Our results indicate that the NBT reduction test can be used to assess the contribution of seminal leukocytes and defective spermatozoa towards ROS generation in semen. Levels of ROS assessed by chemiluminescence assay are strongly correlated with the results of NBT staining.

ROS-dependent HMGA2 upregulation mediates Cd-induced proliferation in MRC-5 cells.

PubMed

Xie, Huaying; Wang, Jiayue; Jiang, Liping; Geng, Chengyan; Li, Qiujuan; Mei, Dan; Zhao, Lian; Cao, Jun

2016-08-01

Cadmium (Cd) is a heavy metal widely found in a number of environmental matrices, and the exposure to Cd is increasing nowadays. In this study, the role of high mobility group A2 (HMGA2) in Cd-induced proliferation was investigated in MRC-5 cells. Exposure to Cd (2μM) for 48h significantly enhanced the growth of MRC-5 cells, increased reactive oxygen species (ROS) production, and induced both mRNA and protein expression of HMGA2. Evidence for Cd-induced reduction of the number of G0/G1 phase cells and an increase in the number of cells in S phase and G2/M phase was sought by flow cytometric analysis. Western blot analysis showed that cyclin D1, cyclin B1, and cyclin E were upregulated in Cd-treated cells. Further study revealed that N-acetyl cysteine (NAC) markedly prevented Cd-induced proliferation of MRC-5 cells, ROS generation, and the increasing protein level of HMGA2. Silencing of HMGA2 gene by siRNA blocked Cd-induced cyclin D1, cyclin B1, and cyclin E expression and reduction of the number of G0/G1 phase cells. Combining, our data showed that Cd-induced ROS formation provoked HMGA2 upregulation, caused cell cycle changes, and led to cell proliferation. This suggests that HMGA2 might be an important biomarker in Cd-induced cell proliferation. Copyright © 2016 Elsevier Ltd. All rights reserved.

Protective Effect of Silibinin on Learning and Memory Impairment in LPS-Treated Rats via ROS-BDNF-TrkB Pathway.

PubMed

Song, Xiaoyu; Zhou, Biao; Zhang, Pingping; Lei, Di; Wang, Yubin; Yao, Guodong; Hayashi, Toshihiko; Xia, Mingyu; Tashiro, Shin-Ichi; Onodera, Satoshi; Ikejima, Takashi

2016-07-01

Silibinin, a flavonoid derived from the herb milk thistle (Silybum marianum), has been used as a hepato-protectant in the clinical treatment of liver disease. In the present study, the effect of silibinin on lipopolysaccharide (LPS)-induced neuroinflammatory impairment in rats is investigated. Injection of LPS into lateral ventricle caused learning and memory impairment. Rats were treated with silibinin to see the effect in comparison with resveratrol as a positive control. Y-maze and Morris water maze tests showed that silibinin significantly attenuated memory damage caused by LPS treatment. At the molecular analysis, the levels of IL-1β and of IL-4 in the hippocampus were decreased and enhanced, respectively, by the treatment with silibinin. NF-κB expression was attenuated by silibinin treatment. Furthermore, generation of total reactive oxygen species (ROS) in the hippocampus was elevated in silibinin-treated groups, and so were the expressions of brain-derived neurotrophic factor (BDNF) and tyrosine receptor kinase B (TrkB). At the same time, LPS-induced reduction of neurons in hippocampus was reversed by silibinin. In conclusion, silibinin ameliorated the impairment of learning and memory of LPS-injection rats, possibly due to the activation of ROS-BDNF-TrkB pathway in the hippocampus as well as the suppression of inflammatory response. This study gives an insight on the beneficial consequences of ROS in central nervous system. Silibinin might be a potential candidate drug for neurodegenerative diseases.

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

Biswas, Debabrata; Sen, Gargi; Sarkar, Avik

Arsenic is an environmental toxicant that reduces the lifespan of circulating erythrocytes during chronic exposure. Our previous studies had indicated involvement of hypercholesterolemia and reactive oxygen species (ROS) in arsenic-induced apoptotic death of erythrocytes. In this study, we have shown an effective recovery from arsenic-induced death signaling in erythrocytes in response to treatment with atorvastatin (ATV) and N-acetyl cysteine (NAC) in rats. Our results emphasized on the importance of cholesterol in the promotion of ROS-mediated Fas signaling in red cells. Arsenic-induced activation of caspase 3 was associated with phosphatidylserine exposure on the cell surface and microvesiculation of erythrocyte membrane. Administrationmore » of NAC in combination with ATV, proved to be more effective than either of the drugs alone towards the rectification of arsenic-mediated disorganization of membrane structural integrity, and this could be linked with decreased ROS accumulation through reduced glutathione (GSH) repletion along with cholesterol depletion. Moreover, activation of caspase 3 was capable of promoting aggregation of band 3 with subsequent binding of autologous IgG and opsonization by C3b that led to phagocytosis of the exposed cells by the macrophages. NAC-ATV treatment successfully amended these events and restored lifespan of erythrocytes from the exposed animals almost to the control level. This work helped us to identify intracellular membrane cholesterol enrichment and GSH depletion as the key regulatory points in arsenic-mediated erythrocyte destruction and suggested a therapeutic strategy against Fas-activated cell death related to enhanced cholesterol and accumulation of ROS.« less

Use of boron cluster-containing redox nanoparticles with ROS scavenging ability in boron neutron capture therapy to achieve high therapeutic efficiency and low adverse effects.

PubMed

Gao, Zhenyu; Horiguchi, Yukichi; Nakai, Kei; Matsumura, Akira; Suzuki, Minoru; Ono, Koji; Nagasaki, Yukio

2016-10-01

A boron delivery system with high therapeutic efficiency and low adverse effects is crucial for a successful boron neutron capture therapy (BNCT). In this study, we developed boron cluster-containing redox nanoparticles (BNPs) via polyion complex (PIC) formation, using a newly synthesized poly(ethylene glycol)-polyanion (PEG-polyanion, possessing a (10)B-enriched boron cluster as a side chain of one of its segments) and PEG-polycation (possessing a reactive oxygen species (ROS) scavenger as a side chain of one of its segments). The BNPs exhibited high colloidal stability, selective uptake in tumor cells, specific accumulation, and long retention in tumor tissue and ROS scavenging ability. After thermal neutron irradiation, significant suppression of tumor growth was observed in the BNP-treated group, with only 5-ppm (10)B in tumor tissues, whereas at least 20-ppm (10)B is generally required for low molecular weight (LMW) (10)B agents. In addition, increased leukocyte levels were observed in the LMW (10)B agent-treated group after thermal neutron irradiation, and not in BNP-treated group, which might be attributed to its ROS scavenging ability. No visual metastasis of tumor cells to other organs was observed 1 month after irradiation in the BNP-treated group. These results suggest that BNPs are promising for enhancing the BNCT performance. Copyright © 2016 Elsevier Ltd. All rights reserved.

Up-regulation of avian uncoupling protein in cold-acclimated and hyperthyroid ducklings prevents reactive oxygen species production by skeletal muscle mitochondria.

PubMed

Rey, Benjamin; Roussel, Damien; Romestaing, Caroline; Belouze, Maud; Rouanet, Jean-Louis; Desplanches, Dominique; Sibille, Brigitte; Servais, Stéphane; Duchamp, Claude

2010-04-28

Although identified in several bird species, the biological role of the avian homolog of mammalian uncoupling proteins (avUCP) remains extensively debated. In the present study, the functional properties of isolated mitochondria were examined in physiological or pharmacological situations that induce large changes in avUCP expression in duckling skeletal muscle. The abundance of avUCP mRNA, as detected by RT-PCR in gastrocnemius muscle but not in the liver, was markedly increased by cold acclimation (CA) or pharmacological hyperthyroidism but was down-regulated by hypothyroidism. Activators of UCPs, such as superoxide with low doses of fatty acids, stimulated a GDP-sensitive proton conductance across the inner membrane of muscle mitochondria from CA or hyperthyroid ducklings. The stimulation was much weaker in controls and not observed in hypothyroid ducklings or in any liver mitochondrial preparations. The production of endogenous mitochondrial reactive oxygen species (ROS) was much lower in muscle mitochondria from CA and hyperthyroid ducklings than in the control or hypothyroid groups. The addition of GDP markedly increased the mitochondrial ROS production of CA or hyperthyroid birds up to, or above, the level of control or hypothyroid ducklings. Differences in ROS production among groups could not be attributed to changes in antioxidant enzyme activities (superoxide dismutase or glutathione peroxidase). This work provides the first functional in vitro evidence that avian UCP regulates mitochondrial ROS production in situations of enhanced metabolic activity.

Up-regulation of avian uncoupling protein in cold-acclimated and hyperthyroid ducklings prevents reactive oxygen species production by skeletal muscle mitochondria

PubMed Central

2010-01-01

Background Although identified in several bird species, the biological role of the avian homolog of mammalian uncoupling proteins (avUCP) remains extensively debated. In the present study, the functional properties of isolated mitochondria were examined in physiological or pharmacological situations that induce large changes in avUCP expression in duckling skeletal muscle. Results The abundance of avUCP mRNA, as detected by RT-PCR in gastrocnemius muscle but not in the liver, was markedly increased by cold acclimation (CA) or pharmacological hyperthyroidism but was down-regulated by hypothyroidism. Activators of UCPs, such as superoxide with low doses of fatty acids, stimulated a GDP-sensitive proton conductance across the inner membrane of muscle mitochondria from CA or hyperthyroid ducklings. The stimulation was much weaker in controls and not observed in hypothyroid ducklings or in any liver mitochondrial preparations. The production of endogenous mitochondrial reactive oxygen species (ROS) was much lower in muscle mitochondria from CA and hyperthyroid ducklings than in the control or hypothyroid groups. The addition of GDP markedly increased the mitochondrial ROS production of CA or hyperthyroid birds up to, or above, the level of control or hypothyroid ducklings. Differences in ROS production among groups could not be attributed to changes in antioxidant enzyme activities (superoxide dismutase or glutathione peroxidase). Conclusion This work provides the first functional in vitro evidence that avian UCP regulates mitochondrial ROS production in situations of enhanced metabolic activity. PMID:20426850

ROS-dependent activation of JNK converts p53 into an efficient inhibitor of oncogenes leading to robust apoptosis

PubMed Central

Shi, Y; Nikulenkov, F; Zawacka-Pankau, J; Li, H; Gabdoulline, R; Xu, J; Eriksson, S; Hedström, E; Issaeva, N; Kel, A; Arnér, E S J; Selivanova, G

2014-01-01

Rescue of the p53 tumor suppressor is an attractive cancer therapy approach. However, pharmacologically activated p53 can induce diverse responses ranging from cell death to growth arrest and DNA repair, which limits the efficient application of p53-reactivating drugs in clinic. Elucidation of the molecular mechanisms defining the biological outcome upon p53 activation remains a grand challenge in the p53 field. Here, we report that concurrent pharmacological activation of p53 and inhibition of thioredoxin reductase followed by generation of reactive oxygen species (ROS), result in the synthetic lethality in cancer cells. ROS promote the activation of c-Jun N-terminal kinase (JNK) and DNA damage response, which establishes a positive feedback loop with p53. This converts the p53-induced growth arrest/senescence to apoptosis. We identified several survival oncogenes inhibited by p53 in JNK-dependent manner, including Mcl1, PI3K, eIF4E, as well as p53 inhibitors Wip1 and MdmX. Further, we show that Wip1 is one of the crucial executors downstream of JNK whose ablation confers the enhanced and sustained p53 transcriptional response contributing to cell death. Our study provides novel insights for manipulating p53 response in a controlled way. Further, our results may enable new pharmacological strategy to exploit abnormally high ROS level, often linked with higher aggressiveness in cancer, to selectively kill cancer cells upon pharmacological reactivation of p53. PMID:24413150

Cytosolic NADP(+)-dependent isocitrate dehydrogenase protects macrophages from LPS-induced nitric oxide and reactive oxygen species.

PubMed

Maeng, Oky; Kim, Yong Chan; Shin, Han-Jae; Lee, Jie-Oh; Huh, Tae-Lin; Kang, Kwang-il; Kim, Young Sang; Paik, Sang-Gi; Lee, Hayyoung

2004-04-30

Macrophages activated by microbial lipopolysaccharides (LPS) produce bursts of nitric oxide and reactive oxygen species (ROS). Redox protection systems are essential for the survival of the macrophages since the nitric oxide and ROS can be toxic to them as well as to pathogens. Using suppression subtractive hybridization (SSH) we found that cytosolic NADP(+)-dependent isocitrate dehydrogenase (IDPc) is strongly upregulated by nitric oxide in macrophages. The levels of IDPc mRNA and of the corresponding enzymatic activity were markedly increased by treatment of RAW264.7 cells or peritoneal macrophages with LPS or SNAP (a nitric oxide donor). Over-expression of IDPc reduced intracellular peroxide levels and enhanced the survival of H2O2- and SNAP-treated RAW264.7 macrophages. IDPc is known to generate NADPH, a cellular reducing agent, via oxidative decarboxylation of isocitrate. The expression of enzymes implicated in redox protection, superoxide dismutase (SOD) and catalase, was relatively unaffected by LPS and SNAP. We propose that the induction of IDPc is one of the main self-protection mechanisms of macrophages against LPS-induced oxidative stress.

Grape seed proanthocyanidin extract protects human umbilical vein endothelial cells from indoxyl sulfate-induced injury via ameliorating mitochondrial dysfunction.

PubMed

Lu, Zhaoyu; Lu, Fuhua; Zheng, Yanqun; Zeng, Yuqun; Zou, Chuan; Liu, Xusheng

2016-01-01

To investigate the effects of grape seed proanthocyanidin extract (GSPE) on indoxyl sulfate-induced Human Umbilical Vein Endothelial Cells (HUVECs) injury in vitro and study its mechanism. HUVECs were incubated with indoxyl sulfate at concentrations in the range found in uremic patients. Then we determined the effect of indoxyl sulfate on endothelial phenotype, endothelial function, ROS (reactive oxygen species), cell apoptosis and mitochondrial function. In addition, we detected whether GSPE can suppress the injury of HUVECs induced by indoxyl sulfate and probe the mechanism underlying the protective effects of GSPE by analyzing mitochondrial dysfunction. GSPE treatment significantly attenuated indoxyl sulfate-induced HVUECs injury in a dose- and time-dependent manner. GSPE-enhanced eNOS and VE-cadherin expression, inhibited intracellular ROS level and cell apoptosis, adjust mitochondrial membrane potential and reduced 8-hydroxy-desoxyguanosine (8-OHdG) level induced by indoxyl sulfate. These results suggest that GSPE prevents HUVECs from indoxyl sulfate-induced injury by ameliorating mitochondrial dysfunction and may be a promising agent for treating uremia toxin-induced injury.

Enhanced nutraceutical potential of gamma irradiated black soybean extracts.

PubMed

Krishnan, Veda; Gothwal, Santosh; Dahuja, Anil; Vinutha, T; Singh, Bhupinder; Jolly, Monica; Praveen, Shelly; Sachdev, Archana

2018-04-15

Radiation processing of soybean, varying in seed coat colour, was carried out at dose levels of 0.25, 0.5 and 1 kGy to evaluate their potential anti-proliferative and cytoprotective effects in an in vitro cell culture system. Irradiated and control black (Kalitur) and yellow (DS9712) soybean extracts were characterized in terms of total phenolics, flavonoids and anthocyanins, especially cyanidin-3-glucoside (C3G). Using an epithelial cell line, BEAS-2B the potential cytoprotective effects of soybean extracts were evaluated in terms of intracellular ROS levels and cell viability. The most relevant scavenging effect was found in Kalitur, with 78% decrease in ROS, which well correlated with a 33% increase in C3G after a 1 kGy dose. Results evidenced a correspondence between in vitro antioxidant activity and a potential health property of black soybean extracts, exemplifying the nutraceutical role of C3G. To our knowledge this study is the first report validating the cytoprotective effects of irradiated black soybean extracts. Copyright © 2017 Elsevier Ltd. All rights reserved.

Enhanced anti-oxidative activity and lignocellulosic ethanol production by biotin addition to medium in Pichia guilliermondii fermentation.

PubMed

Qi, Kai; Xia, Xiao-Xia; Zhong, Jian-Jiang

2015-01-01

Commercialization of lignocellulosic ethanol fermentation requires its high titer, but the reactive oxygen species (ROS) accumulation during the bioprocess damaged the cells and compromised this goal. To improve the cellular anti-oxidative activity during non-detoxified corncob residue hydrolysate fermentation, seed cells were prepared to possess a higher level of intracellular biotin pool (IBP), which facilitated the biosyntheses of catalase and porphyrin. As a result, the catalase activity increased by 1.3-folds compared to control while the ROS level reduced by 50%. Cell viability in high-IBP cells was 1.7-folds of control and the final ethanol titer increased from 31.2 to 41.8 g L(-1) in batch fermentation. The high-IBP cells were further used for repeated-batch fermentation in the non-detoxified lignocellulosic hydrolysate, and the highest titer and average productivity of ethanol reached 63.7 g L(-1) and 1.2 g L(-1)h(-1). The results were favorable to future industrial application of this lignocellulosic bioethanol process. Copyright © 2015 Elsevier Ltd. All rights reserved.

Far-red light-mediated programmable anti-cancer gene delivery in cooperation with photodynamic therapy.

PubMed

Wang, Jinhui; He, Hua; Xu, Xin; Wang, Xiao; Chen, Yongbing; Yin, Lichen

2018-07-01

Effective anti-cancer therapy is hurdled by the complicated extracellular and intracellular barriers, and thus a smart gene vector that can enable programmable gene delivery is highly demanded. Photo-manipulation of gene delivery processes features spatial and temporal precision, while majority of current strategies utilizes short-wavelength UV/visible light with poor tissue penetration or high-power-density near-infrared (NIR) light that would cause undesired heat damage. Herein, an ROS-degradable polycation was designed and co-delivered with a photosensitizer (PS), thus realizing photo-programmable gene delivery using far-red light (661 nm) at low optical power density (down to 5 mW cm -2 ). Thioketal-crosslinked polyethylenimine (TK-PEI) was synthesized to condense p53 gene to form nanocomplexes (NCs), and hyaluronic acid (HA) modified with pheophytin a (Pha) was coated onto NCs to enhance their colloidal stability and enable cancer cell targeting. Short-time (8-min) light irradiation produced non-lethal amount of ROS to disrupt the endosomal membranes and facilitate p53 gene release via degradation of TK-PEI, which collectively enhanced p53 expression levels toward anti-cancer gene therapy. Long-time (30-min) light irradiation at the post-transfection state generated lethal amount of ROS, which cooperatively killed cancer cells to strengthen p53 gene therapy. To the best of our knowledge, this study represents the first example of an "one stone, three birds" approach to realize cooperative anti-cancer gene therapy using low-power-density, long-wavelength visible light as a single stimulus. Copyright © 2018 Elsevier Ltd. All rights reserved.

Reactive oxygen species level in follicular fluid--embryo quality marker in IVF?

PubMed

Das, S; Chattopadhyay, R; Ghosh, S; Ghosh, S; Goswami, S K; Chakravarty, B N; Chaudhury, K

2006-09-01

The impact of oxidative stress in female reproduction is not clear. Contradictory reports on the effect of various oxidative stress markers on follicular fluid, oocytes and embryo quality and fertilization potential exist. The objectives of this study were to examine reactive oxygen species (ROS) levels in follicular fluid of women undergoing IVF and to relate these levels to embryo formation and quality. A total of 208 follicular fluid samples were obtained from 78 women undergoing controlled ovarian stimulation and analysed for ROS and lipid peroxidation (LPO). These samples were divided into groups I and II which represented follicular fluid containing grade III and grade II oocytes, respectively. These groups were further subdivided into groups IA, IB, IIA and IIB according to embryo quality. Subgroups IA and IIA consisted of follicular fluid samples corresponding to grade I/II embryo formation. Subgroups IB and IIB represented fertilization failure/pro-nucleolus (PN) arrest/grade III embryos. No significant correlation was observed in ROS levels on comparing groups I and II (P > 0.05). However, ROS levels were observed to be significantly different on comparing groups IA and IB (P < or = 0.01) and groups IIA and IIB (P < or = 0.05). LPO levels further supported our results. ROS levels in follicular fluid appear to play a significant role in embryo formation and quality.

Autophagy inhibition enhances silibinin-induced apoptosis by regulating reactive oxygen species production in human prostate cancer PC-3 cells.

PubMed

Kim, Sang-Hun; Kim, Kwang-Youn; Yu, Sun-Nyoung; Park, Seul-Ki; Choi, Hyeun-Deok; Ji, Jae-Hoon; Ahn, Soon-Cheol

Silibinin is a major bioactive component of silymarin and has anticancer effects on cancer cell line and has been used as a supportive therapy for chronic inflammatory liver condition. These anticancer effects of silibinin have been demonstrated both in vitro and in vivo cancer models. Although various evidences showed apoptosis signaling pathways by silibinin, there is no report to address the clearly mechanism of silibinin-induced autophagy in prostate cancer PC-3 cells. Our study showed that silibinin triggered autophagy through up-regulation of microtubule-associated protein 1 light chain 3 (LC3)-II, formation of acidic vesicular organelles (AVO) and punctuate of GFP-LC3, which was inhibited by 3-methyladenine (3-MA), an inhibitor of specific autophagy. In addition, silibinin induced autophagy through production of reactive oxygen species (ROS). Inhibition of ROS with diphenyleneiodonium (DPI), a ROS inhibitor, attenuated silibinin-triggered autophagy. Inhibition of autophagy with 3-MA enhanced the silibinin-induced apoptosis through the regulation of caspase-3 and PARP. These results suggested that silibinin induced autophagy by regulating ROS and its mechanism played a protective role against apoptosis in PC-3 cells. Copyright © 2015 Elsevier Inc. All rights reserved.

Hypoxia-induced IL-32β increases glycolysis in breast cancer cells.

PubMed

Park, Jeong Su; Lee, Sunyi; Jeong, Ae Lee; Han, Sora; Ka, Hye In; Lim, Jong-Seok; Lee, Myung Sok; Yoon, Do-Young; Lee, Jeong-Hyung; Yang, Young

2015-01-28

IL-32β is highly expressed and increases the migration and invasion of gastric, lung, and breast cancer cells. Since IL-32 enhances VEGF production under hypoxic conditions, whether IL-32β is regulated by hypoxia was examined. Hypoxic conditions and a mimetic chemical CoCl2 enhanced IL-32β production. When cells were treated with various inhibitors of ROS generation to prevent hypoxia-induced ROS function, IL-32β production was suppressed by both NADPH oxidase and mitochondrial ROS inhibitors. IL-32β translocated to the mitochondria under hypoxic conditions, where it was associated with mitochondrial biogenesis. Thus, whether hypoxia-induced IL-32β is associated with oxidative phosphorylation (OXPHOS) or glycolysis was examined. Glycolysis under aerobic and anaerobic conditions is impaired in IL-32β-depleted cells, and the hypoxia-induced IL-32β increased glycolysis through activation of lactate dehydrogenase. Src is also known to increase lactate dehydrogenase activity, and the hypoxia-induced IL-32β was found to stimulate Src activation by inhibiting the dephosphorylation of Src. These findings revealed that a hypoxia-ROS-IL-32β-Src-glycolysis pathway is associated with the regulation of cancer cell metabolism. Copyright © 2014 Elsevier Ireland Ltd. All rights reserved.

Expression of intracellular reactive oxygen species (ROS) in haematopoietic stem cells (HSCs) correlates with time to neutrophil and platelet engraftment in patients undergoing autologous bone marrow transplantation.

PubMed

Bai, Lijun; Best, Giles; Xia, Wei; Peters, Lyndsay; Wong, Kelly; Ward, Christopher; Greenwood, Matthew

2018-06-19

Reactive oxygen species (ROS) play important roles in haematopoiesis and regulate the self-renewal, migration and myeloid differentiation of haemopoeitic stem cells (HSCs). This study was conducted to determine whether ROS levels in donor HSCs correlate with neutrophil and platelet engraftment in patients following bone marrow transplantation. Cryopreserved HSCs samples from 51 patients who underwent autologous transplantation were studied. Levels of intracellular ROS were assessed by flow cytometry using 2',7' dichlorodihydrofluorescein diacetate (H 2 DCFDA) in the CD45 + /CD34 + HSC population. Colony forming unit (CFU) assays were performed on HSCs isolated from the ROS high and ROS low populations to assess the differentiation potential of these two cell subsets. Distinct populations of ROS high and ROS low cells were evident in all patient samples. The median percentage of ROS high expressing HSCs in the study cohort was 75.8% (range 2% - 95.2%). A significant correlation was identified between the percentage of ROS high stem cells present in the HPC(A) product infused and the time to neutrophil engraftment (p < 0.001, R= - 0.54) as well as time to plt20, plt50 and plt100 (p < 0.001, R = - 0.55, - 0.59 and - 0.56 respectively). The dose of CD34 + / ROS high /kg infused also inversely correlated with a shorter time to neutrophil engraftment; time to engraftment for patients receiving > or ≤ 3 × 10 6 cells/kg was 11.5 (range 9 - 23) days vs. 14 (10 - 28) days respectively (p = 0.02). The dose of ROS high HSCs delivered did not correlate with platelet engraftment. Collectively, these data suggest that the dose of ROS high stem cells delivered to patients may predict time to neutrophil engraftment following autologous transplantation. Copyright © 2018. Published by Elsevier Inc.

[Effect of different oxygen concentrations on biological properties of bone marrow hematopoietic stem cells of mice].

PubMed

Ma, Yi-Ran; Ren, Si-Hua; He, Yu-Xin; Wang, Lin-Lin; Jin, Li; Hao, Yi-Wen

2012-10-01

This study purposed to investigate the effects of different oxygen concentrations and reactive oxygen species (ROS) on the biological characteristics of hematopoietic stem cells (HSC) and their possible mechanisms through simulating oxygen environment to which the peripheral blood HSC are subjected in peripheral blood HSCT. The proliferation ability, cell cycle, directed differentiation ability, ROS level and hematopoietic reconstitution ability of Lin(-)c-kit(+)Sca-1(+) BMHSC were detected by using in vitro amplification test, directional differentiation test, cell cycle analysis, ROS assay and transplantation of Lin(-)c-kit(+)Sca-1(+) HSC from sublethally irradiated mice respectively. The results showed that oxygen concentrations lower than normal oxygen concentration, especially in hypoxic oxygen environment, could reduce ROS generation and amplify more primitive CD34(+)AC133(+) HSC and active CD34(+) HSC, and maintain more stem cells in the G(0)/G(1) phase, which is more helpful to the growth of CFU-S and viability of mice. At the same time, BMHSC exposed to normal oxygen level or inconstant and greatly changed oxygen concentrations could produce a high level of ROS, and the above-mentioned features and functional indicators are relatively low. It is concluded that ROS levels of HSC in BMHSCT are closely related with the oxygen concentration surrounding the cells and its stability. Low oxygen concentration and antioxidant intervention are helpful to transplantation of BMHSC.

Role of nanomaterials in plants under challenging environments.

PubMed

Khan, M Nasir; Mobin, M; Abbas, Zahid Khorshid; AlMutairi, Khalid A; Siddiqui, Zahid H

2017-01-01

The application of nanostructured materials, designed for sustainable crop production, reduces nutrient losses, suppresses disease and enhances the yields. Nanomaterials (NMs), with a particle size less than 100 nm, influence key life events of the plants that include seed germination, seedling vigor, root initiation, growth and photosynthesis to flowering. Additionally, NMs have been implicated in the protection of plants against oxidative stress as they mimic the role of antioxidative enzymes such as superoxide dismutase (SOD), catalase (CAT) and peroxidase (POX). However, besides their beneficial effects on plants, applications of NMs have been proved to be phytotoxic too as they enhance the generation of reactive oxygen species (ROS). The elevated level of ROS may damage the cellular membranes, proteins and nucleic acids. Therefore, in such a conflicting and ambiguous nature of NMs in plants, it is necessary to decipher the mechanism of cellular, biochemical and molecular protection render by NMs under stressful environmental conditions. This review systematically summarizes the role of NMs in plants under abiotic stresses such as drought, salt, temperature, metal, UV-B radiation and flooding. Furthermore, suitable strategies adopted by plants in presence of NMs under challenging environments are also being presented. Copyright © 2016 Elsevier Masson SAS. All rights reserved.

Restoring the IL-1β/NF-κB-induced impaired chondrogenesis by diallyl disulfide in human adipose-derived mesenchymal stem cells via attenuation of reactive oxygen species and elevation of antioxidant enzymes.

PubMed

Bahrampour Juybari, Kobra; Kamarul, Tunku; Najafi, Mohammad; Jafari, Davood; Sharifi, Ali Mohammad

2018-03-26

Strategies based on mesenchymal stem cell (MSC) therapy for restoring injured articular cartilage are not effective enough in osteoarthritis (OA). Due to the enhanced inflammation and oxidative stress in OA microenvironment, differentiation of MSCs into chondrocytes would be impaired. This study aims to explore the effects of diallyl disulfide (DADS) on IL-1β-mediated inflammation and oxidative stress in human adipose derived mesenchymal stem cells (hADSCs) during chondrogenesis. MTT assay was employed to examine the effects of various concentrations of DADS on the viability of hADSCs at different time scales to obtain non-cytotoxic concentration range of DADS. The effects of DADS on IL-1β-induced intracellular ROS generation and lipid peroxidation were evaluated in hADSCs. Western blotting was used to analyze the protein expression levels of IκBα (np), IκBα (p), NF-κB (np) and NF-κB (p). Furthermore, the gene expression levels of antioxidant enzymes in hADSCs and chondrogenic markers at days 7, 14 and 21 of differentiation were measured using qRT-PCR. The results showed that addition of DADS significantly enhanced the mRNA expression levels of antioxidant enzymes as well as reduced ROS elevation, lipid peroxidation, IκBα activation and NF-κB nuclear translocation in hADSCs treated with IL-1β. In addition, DADS could significantly increase the expression levels of IL-1β-induced impaired chondrogenic marker genes in differentiated hADSCs. Treatment with DADS may provide an effective approach to prevent the pro-inflammatory cytokines and oxidative stress as catabolic causes of chondrocyte cell death and enhance the protective anabolic effects by promoting chondrogenesis associated gene expressions in hADSCs exposed to OA condition.

Anti-Oxidative Stress Activity Is Essential for Amanita caesarea Mediated Neuroprotection on Glutamate-Induced Apoptotic HT22 Cells and an Alzheimer’s Disease Mouse Model

PubMed Central

Li, Zhiping; Chen, Xia; Lu, Wenqian; Zhang, Shun; Guan, Xin; Li, Zeyu; Wang, Di

2017-01-01

Amanita caesarea, an edible mushroom found mainly in Asia and southern Europe, has been reported to show good antioxidative activities. In the present study, the neuroprotective effects of A. caesarea aqueous extract (AC) were determined in an l-glutamic acid (l-Glu) induced HT22 cell apoptosis model, and in a d-galactose (d-gal) and AlCl3-developed experimental Alzheimer’s disease (AD) mouse model. In 25 mM of l-Glu-damaged HT22 cells, a 3-h pretreatment with AC strongly improved cell viability, reduced the proportion of apoptotic cells, restored mitochondrial function, inhibited the over-production of intracellular reactive oxygen species (ROS) and Ca2+, and suppressed the high expression levels of cleaved-caspase-3, calpain 1, apoptosis-inducing factor (AIF) and Bax. Compared with HT22 exposed only to l-Glu cells, AC enhanced the phosphorylation activities of protein kinase B (Akt) and the mammalian target of rapamycin (mTOR), and suppressed the phosphorylation activities of phosphatase and tensin homolog deleted on chromosome ten (PTEN). In the experimental AD mouse, 28-day AC administration at doses of 250, 500, and 1000 mg/kg/day strongly enhanced vertical movements and locomotor activities, increased the endurance time in the rotarod test, and decreased the escape latency time in the Morris water maze test. AC also alleviated the deposition of amyloid beta (Aβ) in the brain and improved the central cholinergic system function, as indicated by an increase acetylcholine (Ach) and choline acetyltransferase (ChAT) concentrations and a reduction in acetylcholine esterase (AchE) levels. Moreover, AC reduced ROS levels and enhanced superoxide dismutase (SOD) levels in the brain of experimental AD mice. Taken together, our data provide experimental evidence that A. caesarea may serve as potential food for treating or preventing neurodegenerative diseases. PMID:28749416

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

PubMed

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

2017-01-01

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

Oxidative stress regulates autophagy in cultured muscle cells of patients with chronic obstructive pulmonary disease.

PubMed

Gouzi, Fares; Blaquière, Marine; Catteau, Matthias; Bughin, François; Maury, Jonathan; Passerieux, Emilie; Ayoub, Bronia; Mercier, Jacques; Hayot, Maurice; Pomiès, Pascal

2018-06-26

The proteolytic autophagy pathway is enhanced in the lower limb muscles of patients with chronic obstructive pulmonary disease (COPD). Reactive oxygen species (ROS) have been shown to regulate autophagy in the skeletal muscles, but the role of oxidative stress in the muscle autophagy of patients with COPD is unknown. We used cultured myoblasts and myotubes from the quadriceps of eight healthy subjects and twelve patients with COPD (FEV1% predicted: 102.0% and 32.0%, respectively; p < 0.0001). We compared the autophagosome formation, the expression of autophagy markers, and the autophagic flux in healthy subjects and the patients with COPD, and we evaluated the effects of the 3-methyladenine (3-MA) autophagy inhibitor on the atrophy of COPD myotubes. Autophagy was also assessed in COPD myotubes treated with an antioxidant molecule, ascorbic acid. Autophagosome formation was increased in COPD myoblasts and myotubes (p = 0.011; p < 0.001), and the LC3 2/LC3 1 ratio (p = 0.002), SQSTM1 mRNA and protein expression (p = 0.023; p = 0.007), BNIP3 expression (p = 0.031), and autophagic flux (p = 0.002) were higher in COPD myoblasts. Inhibition of autophagy with 3-MA increased the COPD myotube diameter (p < 0.001) to a level similar to the diameter of healthy subject myotubes. Treatment of COPD myotubes with ascorbic acid decreased ROS concentration (p < 0.001), ROS-induced protein carbonylation (p = 0.019), the LC3 2/LC3 1 ratio (p = 0.037), the expression of SQSTM1 (p < 0.001) and BNIP3 (p < 0.001), and increased the COPD myotube diameter (p < 0.001). Thus, autophagy signaling is enhanced in cultured COPD muscle cells. Furthermore, the oxidative stress level contributes to the regulation of autophagy, which is involved in the atrophy of COPD myotubes in vitro. © 2018 Wiley Periodicals, Inc.

Lysophosphatidic acid induces reactive oxygen species generation by activating protein kinase C in PC-3 human prostate cancer cells

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

Lin, Chu-Cheng; Lin, Chuan-En; Lin, Yueh-Chien

2013-11-01

Highlights: •LPA induces ROS generation through LPA{sub 1} and LPA{sub 3}. •LPA induces ROS generation by activating PLC. •PKCζ mediates LPA-induced ROS generation. -- Abstract: Prostate cancer is one of the most frequently diagnosed cancers in males, and PC-3 is a cell model popularly used for investigating the behavior of late stage prostate cancer. Lysophosphatidic acid (LPA) is a lysophospholipid that mediates multiple behaviors in cancer cells, such as proliferation, migration and adhesion. We have previously demonstrated that LPA enhances vascular endothelial growth factor (VEGF)-C expression in PC-3 cells by activating the generation of reactive oxygen species (ROS), which ismore » known to be an important mediator in cancer progression. Using flow cytometry, we showed that LPA triggers ROS generation within 10 min and that the generated ROS can be suppressed by pretreatment with the NADPH oxidase (Nox) inhibitor diphenylene iodonium. In addition, transfection with LPA{sub 1} and LPA{sub 3} siRNA efficiently blocked LPA-induced ROS production, suggesting that both receptors are involved in this pathway. Using specific inhibitors and siRNA, phospholipase C (PLC) and protein kinase C (PKC) were also suggested to participate in LPA-induced ROS generation. Overall, we demonstrated that LPA induces ROS generation in PC-3 prostate cancer cells and this is mediated through the PLC/PKC/Nox pathway.« less

Sublethal concentrations of salicylic acid decrease the formation of reactive oxygen species but maintain an increased nitric oxide production in the root apex of the ethylene-insensitive Never ripe tomato mutants

PubMed Central

Poór, Péter; Gémes, Katalin

2011-01-01

The pattern of salicylic acid (SA)-induced production of reactive oxygen species (ROS) and nitric oxide (NO) were different in the apex of adventitious roots in wild-type and in the ethylene-insensitive Never ripe (Nr) mutants of tomato (Solanum lycopersicum L. cv Ailsa Craig). ROS were upregulated, while NO remained at the control level in apical root tissues of wildtype plants exposed to sublethal concentrations of SA. In contrast, Nr plants expressing a defective ethylene receptor displayed a reduced level of ROS and a higher NO content in the apical root cells. In wild-type plants NO production seems to be ROS(H2O2)-dependent at cell death-inducing concentrations of SA, indicating that ROS and NO may interact to trigger oxidative cell death. In the absence of significant ROS accumulation, the increased NO production caused moderate reduction in cell viability in root apex of Nr plants exposed to 10−3 M SA. This suggests that a functional ethylene signaling pathway is necessary for the control of ROS and NO production induced by SA. PMID:21847015

Ascorbic acid and reactive oxygen species are involved in the inhibition of seed germination by abscisic acid in rice seeds

PubMed Central

Ye, Nenghui; Zhu, Guohui; Liu, Yinggao; Liu, Rui; Shi, Lu; Jia, Liguo; Zhang, Jianhua

2012-01-01

The antagonism between abscisic acid (ABA) and gibberellin (GA) plays a key role in controlling seed germination, but the mechanism of antagonism during this process is not known. The possible links among ABA, reactive oxygen species (ROS), ascorbic acid (ASC), and GA during rice seed germination were investigated. Unlike in non-seed tissues where ROS production is increased by ABA, ABA reduced ROS production in imbibed rice seeds, especially in the embryo region. Such reduced ROS also led to an inhibition of ASC production. GA accumulation was also suppressed by a reduced ROS and ASC level, which was indicated by the inhibited expression of GA biosynthesis genes, amylase genes, and enzyme activity. Application of exogenous ASC can partially rescue seed germination from ABA treatment. Production of ASC, which acts as a substrate in GA biosynthesis, was significantly inhibited by lycorine which thus suppressed the accumulation of GA. Consequently, expression of GA biosynthesis genes was suppressed by the low levels of ROS and ASC in ABA-treated seeds. It can be concluded that ABA regulates seed germination in multiple dimensions. ROS and ASC are involved in its inhibition of GA biosynthesis. PMID:22200664

Electron Transport Chain-dependent and -independent Mechanisms of Mitochondrial H2O2 Emission during Long-chain Fatty Acid Oxidation*

PubMed Central

Seifert, Erin L.; Estey, Carmen; Xuan, Jian Y.; Harper, Mary-Ellen

2010-01-01

Oxidative stress in skeletal muscle is a hallmark of various pathophysiologic states that also feature increased reliance on long-chain fatty acid (LCFA) substrate, such as insulin resistance and exercise. However, little is known about the mechanistic basis of the LCFA-induced reactive oxygen species (ROS) burden in intact mitochondria, and elucidation of this mechanistic basis was the goal of this study. Specific aims were to determine the extent to which LCFA catabolism is associated with ROS production and to gain mechanistic insights into the associated ROS production. Because intermediates and by-products of LCFA catabolism may interfere with antioxidant mechanisms, we predicted that ROS formation during LCFA catabolism reflects a complex process involving multiple sites of ROS production as well as modified mitochondrial function. Thus, we utilized several complementary approaches to probe the underlying mechanism(s). Using skeletal muscle mitochondria, our findings indicate that even a low supply of LCFA is associated with ROS formation in excess of that generated by NADH-linked substrates. Moreover, ROS production was evident across the physiologic range of membrane potential and was relatively insensitive to membrane potential changes. Determinations of topology and membrane potential as well as use of inhibitors revealed complex III and the electron transfer flavoprotein (ETF) and ETF-oxidoreductase, as likely sites of ROS production. Finally, ROS production was sensitive to matrix levels of LCFA catabolic intermediates, indicating that mitochondrial export of LCFA catabolic intermediates can play a role in determining ROS levels. PMID:20032466

Low concentrations of salicylic acid delay methyl jasmonate-induced leaf senescence by up-regulating nitric oxide synthase activity.

PubMed

Ji, Yingbin; Liu, Jian; Xing, Da

2016-09-01

In plants, extensive efforts have been devoted to understanding the crosstalk between salicylic acid (SA) and jasmonic acid (JA) signaling in pathogen defenses, but this crosstalk has scarcely been addressed during senescence. In this study, the effect of SA application on methyl jasmonate (MeJA)-induced leaf senescence was assessed. We found that low concentrations of SA (1-50 μM) played a delayed role against the senescence promoted by MeJA. Furthermore, low concentrations of SA enhanced plant antioxidant defenses and restricted reactive oxygen species (ROS) accumulation in MeJA-treated leaves. When applied simultaneously with MeJA, low concentrations of SA triggered a nitric oxide (NO) burst, and the elevated NO levels were linked to the nitric oxide associated 1 (NOA1)-dependent pathway via nitric oxide synthase (NOS) activity. The ability of SA to up-regulate plant antioxidant defenses, reduce ROS accumulation, and suppress leaf senescence was lost in NO-deficient Atnoa1 plants. In a converse manner, exogenous addition of NO donors increased the plant antioxidant capacity and lowered the ROS levels in MeJA-treated leaves. Taken together, the results indicate that SA at low concentrations counteracts MeJA-induced leaf senescence through NOA1-dependent NO signaling and strengthening of the antioxidant defense. © The Author 2016. Published by Oxford University Press on behalf of the Society for Experimental Biology. All rights reserved. For permissions, please email: journals.permissions@oup.com.

[Relationship among the Oxygen Concentration, Reactive Oxygen Species and the Biological Characteristics of Mouse Bone Marrow Hematopoietic Stem Cells].

PubMed

Ren, Si-Hua; He, Yu-Xin; Ma, Yi-Ran; Jin, Jing-Chun; Kang, Dan

2016-02-01

To investigate the effects of oxygen concentration and reactive oxygen species (ROS) on the biological characteristics of hematopoietic stem cells (HSC) and to analyzed the relationship among the oxygen concentration, ROS and the biological characteristics of mouse HSC through simulation of oxygen environment experienced by PB HSC during transplantation. The detection of reactive oxygen species (ROS), in vitro amplification, directional differentiation (BFU-E, CFU-GM, CFU-Mix), homing of adhesion molecules (CXCR4, CD44, VLA4, VLA5, P-selectin), migration rate, CFU-S of NOD/SCID mice irradiated with sublethal dose were performed to study the effect of oxgen concentration and reactive oxygen species on the biological characteristics of mouse BM-HSC and the relationship among them. The oxygen concentrations lower than normal oxygen concentration (especially hypoxic oxygen environment) could reduce ROS level and amplify more Lin(-) c-kit(+) Sca-1(+) BM HSC, which was more helpful to the growth of various colonies (BFU-E, CFU-GM, CFU-Mix) and to maintain the migratory ability of HSC, thus promoting CFU-S growth significantly after the transplantation of HSC in NOD/SCID mice irradiated by a sublethal dose. BM HSC exposed to oxygen environments of normal, inconstant oxygen level and strenuously thanging of oxygen concentration could result in higher level of ROS, at the same time, the above-mentioned features and functional indicators were relatively lower. The ROS levels of BM HSC in PB HSCT are closely related to the concentrations and stability of oxygen surrounding the cells. High oxygen concentration results in an high level of ROS, which is not helpful to maintain the biological characteristics of BM HSC. Before transplantation and in vitro amplification, the application of antioxidancs and constant oxygen level environments may be beneficial for transplantation of BMMSC.

ROS and ROS-Mediated Cellular Signaling

PubMed Central

Zhang, Jixiang; Wang, Xiaoli; Vikash, Vikash; Ye, Qing; Wu, Dandan; Liu, Yulan; Dong, Weiguo

2016-01-01

It has long been recognized that an increase of reactive oxygen species (ROS) can modify the cell-signaling proteins and have functional consequences, which successively mediate pathological processes such as atherosclerosis, diabetes, unchecked growth, neurodegeneration, inflammation, and aging. While numerous articles have demonstrated the impacts of ROS on various signaling pathways and clarify the mechanism of action of cell-signaling proteins, their influence on the level of intracellular ROS, and their complex interactions among multiple ROS associated signaling pathways, the systemic summary is necessary. In this review paper, we particularly focus on the pattern of the generation and homeostasis of intracellular ROS, the mechanisms and targets of ROS impacting on cell-signaling proteins (NF-κB, MAPKs, Keap1-Nrf2-ARE, and PI3K-Akt), ion channels and transporters (Ca2+ and mPTP), and modifying protein kinase and Ubiquitination/Proteasome System. PMID:26998193

Bicarbonate Modulates Photoreceptor Guanylate Cyclase (ROS-GC) Catalytic Activity*

PubMed Central

Duda, Teresa; Wen, Xiao-Hong; Isayama, Tomoki; Sharma, Rameshwar K.; Makino, Clint L.

2015-01-01

By generating the second messenger cGMP in retinal rods and cones, ROS-GC plays a central role in visual transduction. Guanylate cyclase-activating proteins (GCAPs) link cGMP synthesis to the light-induced fall in [Ca2+]i to help set absolute sensitivity and assure prompt recovery of the response to light. The present report discloses a surprising feature of this system: ROS-GC is a sensor of bicarbonate. Recombinant ROS-GCs synthesized cGMP from GTP at faster rates in the presence of bicarbonate with an ED50 of 27 mm for ROS-GC1 and 39 mm for ROS-GC2. The effect required neither Ca2+ nor use of the GCAPs domains; however, stimulation of ROS-GC1 was more powerful in the presence of GCAP1 or GCAP2 at low [Ca2+]. When applied to retinal photoreceptors, bicarbonate enhanced the circulating current, decreased sensitivity to flashes, and accelerated flash response kinetics. Bicarbonate was effective when applied either to the outer or inner segment of red-sensitive cones. In contrast, bicarbonate exerted an effect when applied to the inner segment of rods but had little efficacy when applied to the outer segment. The findings define a new regulatory mechanism of the ROS-GC system that affects visual transduction and is likely to affect the course of retinal diseases caused by cGMP toxicity. PMID:25767116