GSH Peroxidase Research Articles

Oxaliplatin aggravates hepatic oxidative stress, inflammation and fibrosis in a non‑alcoholic fatty liver disease mouse model.

Oxaliplatin (OXA)-based chemotherapy is widely used in the treatment of gastrointestinal tumors; however, it is associated with chemotherapy-associated liver injury. Whether OXA induces liver injury and aggravates the already existing hepatic oxidative stress, inflammation and fibrosis in non-alcoholic fatty liver disease (NAFLD), and whether these effects can be alleviated by reduced glutathione (GSH) treatment, remains unclear. In the present study, OXA induced acute liver injury in NAFLD mice. Moreover, OXA increased the levels of reactive oxygen species (ROS) and malondialdehyde (MDA) and decreased the levels of superoxide dismutase and GSH peroxidase in the livers of NAFLD mice. OXA also induced the upregulation of hepatic inflammatory cytokines, such as tumor necrosis factor (TNF)-α, interferon (IFN)-γ and interleukin (IL)-17, in NAFLD mice. Furthermore, collagen fiber deposition in liver tissues was increased and the expression of transforming growth factor (TGF)-β, α-smooth muscle actin (SMA) and tissue inhibitor of metallopeptidase (TIMP)-1 was upregulated in the livers of OXA-treated NAFLD mice. Treatment with exogenous GSH alleviated OXA-induced acute liver injury in NAFLD mice, and significantly reduced the levels of ROS, MDA and TNF-α. However, GSH treatment did not inhibit collagen fiber deposition, although it reduced the levels of IFN-γ, IL-17, TGF-β, α-SMA and TIMP-1 in the livers of OXA-treated NAFLD mice. In conclusion, OXA chemotherapy may induce acute liver injury and aggravate the existing hepatic oxidative stress, inflammation and fibrosis in NAFLD. Treatment of NAFLD mice with exogenous GSH alleviated OXA-induced liver injury, possibly by ameliorating OXA-aggravated hepatic oxidative stress and inflammation; it did not, however, attenuate OXA-aggravated liver fibrosis.

Altered skeletal muscle redox status, structural integrity, and ryanodine receptor are associated with contractile dysfunction following systemic iron loading in mice

We previously reported that a moderate degree of systemic iron loading caused muscle functional impairment in mice. Such deterioration was not attributed to oxidative stress since it did not incur protein or lipid oxidative damage. On the other hand, muscle contractile dysfunction was associated with increased thioredoxin protein levels, suggestive of altered redox signaling. Thus, the purpose of this study was to further examine skeletal muscle redox status and potential meditators of contractile dysfunction following a physiologically‐relevant degree of iron loading. Twelve‐week‐old male CD‐1 mice received subcutaneous injections of iron (4 mg iron dextran/200 μL) or vehicle 5 days/week for 2 weeks (n=10/group). One day following the last injection the gastrocnemius muscles were harvested for measurement of biochemical parameters. Systemic iron loading elevated the muscle non‐heme iron (NHI) concentration by approximately 4‐fold (P < 0.001). Although reduced glutathione GSH (P = 0.39) and glutathione peroxidase (GPX) activity (P = 0.82) measures were similar between the two groups, iron‐loaded mice displayed greater glutathione disulfide (GSSG; P = 0.03) and GSSG/GSH ratio (P = 0.03), which are sensitive markers of oxidative stress and redox status. In addition, redox regulator glutaredoxin‐2 (GRX2) protein expression was lower in the muscle of iron‐loaded mice compared with controls (P = 0.04). Muscle structural integrity marker αII‐spectrin at 240 kDa was lower in the iron‐loaded muscles compared with controls (P = 0.02). No differences were observed in its cleavage products at 150 kDa (P = 0.41) or 120 kDa (P = 0.11). Similar to αII‐spectrin, protein levels of focal adhesion α‐actinin were also lower in the iron‐loaded gastrocnemius (P = 0.04). Levels of calstabin‐1 associated with ryanodine receptor (RyR1) were lower in iron‐loaded muscles compared with controls (P = 0.04), while total RyR1 (P = 0.99) was similar between groups. In summary, contractile dysfunction that results from moderate iron loading may be mediated by a disturbance in the muscle redox balance and from changes arising from an increased proteolytic response and aberrant sarcoplasmic reticulum Ca2+ release.Support or Funding InformationSupported by the Syracuse University SOEThis abstract is from the Experimental Biology 2019 Meeting. There is no full text article associated with this abstract published in The FASEB Journal.

Pancreatic β-cells detoxify H2O2 through the peroxiredoxin/thioredoxin antioxidant system

Oxidative stress is thought to promote pancreatic β-cell dysfunction and contribute to both type 1 and type 2 diabetes. Reactive oxygen species (ROS), such as superoxide and hydrogen peroxide, are mediators of oxidative stress that arise largely from electron leakage during oxidative phosphorylation. Reports that β-cells express low levels of antioxidant enzymes, including catalase and GSH peroxidases, have supported a model in which β-cells are ill-equipped to detoxify ROS. This hypothesis seems at odds with the essential role of β-cells in the control of metabolic homeostasis and organismal survival through exquisite coupling of oxidative phosphorylation, a prominent ROS-producing pathway, to insulin secretion. Using glucose oxidase to deliver H2O2 continuously over time and Amplex Red to measure extracellular H2O2 concentration, we found here that β-cells can remove micromolar levels of this oxidant. This detoxification pathway utilizes the peroxiredoxin/thioredoxin antioxidant system, as selective chemical inhibition or siRNA-mediated depletion of thioredoxin reductase sensitized β-cells to continuously generated H2O2 In contrast, when delivered as a bolus, H2O2 induced the DNA damage response, depleted cellular energy stores, and decreased β-cell viability independently of thioredoxin reductase inhibition. These findings show that β-cells have the capacity to detoxify micromolar levels of H2O2 through a thioredoxin reductase-dependent mechanism and are not as sensitive to oxidative damage as previously thought.

Prenatal exposure to pyrrolizidine alkaloids induced hepatotoxicity and pulmonary injury in fetal rats

Hepatic and pulmonary toxicity in fetal rats induced by pyrrolizidine alkaloids (PAs) was investigated. Retrorsine (RTS) or monocrotaline (MCT) was intragastrically administered during pregnancy. The reduction of body and tail lengths was consistent with body weight loss in PA-exposed fetuses, and pathological lesions in liver and lung were observed only in fetuses. Both PAs reduced fetal serum transaminase activities. The GSH/GSSG ratio, GSH peroxidase and superoxide dismutase activities also decreased but glutathione S-transferase activity increased in fetal lung, especially for MCT. The pyrrole-protein adducts in fetal liver and lung could be detected, and those adducts in RTS fetal lungs were about 65% of those in MCT group. In conclusion, prenatal PAs exposure induced fetal hepatic and pulmonary toxicities through the generation of pyrrole metabolites and oxidative injury. The difference on fetal pulmonary redox homeostasis between two PAs groups might be associated with the content of PAs migrated to fetal lungs.

Glutathione-redox status on hydro alcoholic root bark extract of Premna integrifolia Linn in high fat diet induced atherosclerosis model

BackgroundPremna integrifolia Linn. is a medicinal plant of an Ayurvedic importance and proved to have an anti-inflammatory, anti-diabetic, anti-microbial and hypo-lipidemic activity. Glutathione (GSH) redox status is an important parameter to assess the antioxidant activity of any neutraceuticals. ObjectiveIn order to assess the anti-oxidant potential of hydro alcoholic extract (HAE) of P. integrifolia, this study was aimed to evaluate the GSH redox status in high fat diet induced experimental atherosclerosis. Materials and methodsThe present study comprises sixty Wistar rats and they were divided into six groups: the first group served as control, the second group was fed with high fat diet and the third, fourth and fifth groups were fed with high fat diet along with various concentrations of HAE of 200, 400 and 500 g/kg.b.wt respectively and the sixth group was administered high fat diet along with 10 mg/kg b.wt of atorvastatin for 30 days. GSH-dependent enzymes like GSH-peroxidase (GPx), GSH-reductase (GR) and glucose 6-phosphate dehydrogenase (G6PD) were estimated in hemolysate, kidney, heart and liver of experimental rats. ResultsAnalysis of GSH levels showed a significant decrease in hemolysate, heart and kidney (p < 0.05) and liver (p < 0.01) in high fat-fed rats when compared to control. Activities of GPx, GR and G6PD in hemolysate and heart (p < 0.001), liver and kidney (p < 0.05) in high fat-fed rats when compared to control. Dose-dependent increase was observed in rats treated with various concentrations of HAE. ConclusionThe HAE of root bark of P. integrifolia is proved to have a protective role on antioxidant defense in high fat diet induced atherosclerosis model. As a whole P. integrifolia increases the GSH content in a dose-dependent manner and in turn altered the redox cycle.

Thioredoxin Reductase-1 Inhibition Augments Endogenous Glutathione-Dependent Antioxidant Responses in Experimental Bronchopulmonary Dysplasia.

Background Aurothioglucose- (ATG-) mediated inhibition of thioredoxin reductase-1 (TXNRD1) improves alveolarization in experimental murine bronchopulmonary dysplasia (BPD). Glutathione (GSH) mediates susceptibility to neonatal and adult oxidative lung injury. We have previously shown that ATG attenuates hyperoxic lung injury and enhances glutathione- (GSH-) dependent antioxidant defenses in adult mice. Hypothesis The present studies evaluated the effects of TXNRD1 inhibition on GSH-dependent antioxidant defenses in newborn mice in vivo and lung epithelia in vitro. Methods Newborn mice received intraperitoneal ATG or saline prior to room air or 85% hyperoxia exposure. Glutamate-cysteine ligase (GCL) catalytic (Gclc) and modifier (Gclm) mRNA levels, total GSH levels, total GSH peroxidase (GPx) activity, and Gpx2 expression were determined in lung homogenates. In vitro, murine transformed club cells (mtCCs) were treated with the TXNRD1 inhibitor auranofin (AFN) or vehicle in the presence or absence of the GCL inhibitor buthionine sulfoximine (BSO). Results In vivo, ATG enhanced hyperoxia-induced increases in Gclc mRNA levels, total GSH contents, and GPx activity. In vitro, AFN increased Gclm mRNA levels, intracellular and extracellular GSH levels, and GPx activity. BSO prevented AFN-induced increases in GSH levels. Conclusions Our data are consistent with a model in which TXNRD1 inhibition augments hyperoxia-induced GSH-dependent antioxidant responses in neonatal mice. Discrepancies between in vivo and in vitro results highlight the need for methodologies that permit accurate assessments of the GSH system at the single-cell level.

Impact of a dietary challenge with peroxidized oil on the glutathione redox status and integrity of the small intestine in weaned piglets

Glutathione (GSH) is considered to play an important role in maintaining the integrity of the small intestine. In piglets, altered mucosal GSH levels might therefore be involved in weaning-induced changes of the small intestinal morphology and barrier function. To test this hypothesis, we aimed to challenge the mucosal GSH redox status during the first 28 days after weaning, by feeding diets containing 5% fresh linseed oil (CON), or 2.5% (OF1) or 5% (OF2) peroxidized linseed oil (peroxide value 225 mEq O2/kg oil) and exploring the effects on gut integrity. Piglets were pair-fed and had a total daily feed allowance of 32 g/kg BW. A fourth treatment included animals that were fed the control diet ad libitum (ACON). Animals were sampled at days 5 and 28 post-weaning. The malondialdehyde (MDA) concentration and GSH redox status (GSH/GSSG Eh) were determined in blood, liver and small intestinal mucosa. Histomorphology of the duodenal and jejunal mucosa was determined, and Ussing chambers were used to assess fluorescein isothiocyanate dextran (FD4) and horseradish peroxidase (HRP) fluxes across the mucosa. Results show that peroxidized linseed oil imposed an oxidative challenge at day 28, but not at day 5 post-weaning. At day 28, increasing levels of dietary peroxides to pair-fed pigs linearly increased MDA levels in duodenal and jejunal mucosa. Moreover, FD4 fluxes were significantly increased in OF1 (+75%) and OF2 (+64%) in the duodenum, and HRP fluxes tended (P=0.099) to show similar differences, as compared to CON. This co-occurred with a significant 11 mV increase of the hepatic GSH/GSSG Eh, potentiated by a significantly increased GSH peroxidase activity for treatments OF1 (+47%) and OF2 (+63%) in liver as compared to CON. Furthermore; duodenal HRP flux significantly correlated with the hepatic glutathione disulphide (GSSG) level (r=0.650), as also observed in the jejunum for hepatic GSSG (r=0.627) and GSH/GSSG Eh (r=0.547). The jejunal permeability was not affected, but FD4 and HRP fluxes significantly correlated with the local GSH (r=0.619; r=0.733) and GSSG (r=0.635; r=0586) levels. Small intestinal histomorphology was not affected by dietary lipid peroxides, nor were there any correlations found with the GSH redox system. To conclude, under oxidative stress conditions, jejunal barrier function is related to the local and hepatic GSH redox system. It is suggested that the hepatic GSH system participates in the elimination of luminal peroxides, and thereby impacts on duodenal barrier function.

Protective effect of dihydromyricetin revents fatty liver through nuclear factor‑κB/p53/B‑cell lymphoma 2‑associated X protein signaling pathways in a rat model.

Dihydromyricetin is the major flavonoid in vine tea, whose pharmacological action has attracted increasing attention in recent years. The triglyceride, albumin (ALB), alanine aminotransferase, aspartate aminotransferase, malondialdehyde, superoxide dismutase, glutathione (GSH), GSH peroxidase, tumor necrosis factor-α, interleukin (IL)-1β, IL-6 and IL-18 expression levels were measured using enzyme-linked immunosorbent assay kits. The protein levels of ALB and collagen I, PPARα, NF-κB, p53 and Bax were used to measure using western blotting. The results revealed that dihydromyricetin prevented the development of fatty liver, and inhibited oxidative stress, inflammation and apoptosis in a fatty liver rat model. In addition, treatment with dihydromyricetin inhibited the levels of ALB and collagen I, while it induced peroxisome proliferator-activated receptor α protein expression. Dihydromyricetin also suppressed the protein expression levels of nuclear factor (NF)-κB, p53 and B-cell lymphoma 2-associated X protein (Bax) in the rat model. Collectively, it is concluded that dihydromyricetin exerted a protective effect on fatty liver through NF-κB/p53/Bax signaling pathways in a rat model.

Cytoprotective effects of molsidomine against methotrexate-induced hepatotoxicity: an experimental rat study.

Introduction and aimMethotrexate (Mtx) is an antineoplastic and immunosuppressive drug that may cause hepatotoxicity, whereas molsidomine (Mol) is a vasodilating and antioxidant agent. This study aimed to investigate the potential protective effects of Mol in Mtx-induced liver toxicity in rats.Materials and methodsForty Wistar albino rats were equally divided into five groups: control, Mol, Mtx, Mol–Mtx, and Mtx–Mol. Following treatment, the animals were sacrificed, and liver tissue samples were histopathologically evaluated using Roening grading and Bcl-2 antibody staining. Tissue oxidants, antioxidants, and serum transaminases were measured and statistically compared across all groups.ResultsNo hepatic fibrosis or steatosis was observed in any of the groups. In the Mtx group, grade 2 liver injury and score 2 Bcl-2 antibody staining were observed; however, in the Mol–Mtx group, these were lower (grade 1, score 1). There were no statistically significant differences in serum transaminase levels among groups. Malondialdehyde levels were higher in all rats that received Mtx, but no differences in myeloperoxidase levels were observed among the groups. Levels of tissue antioxidants, including superoxide dismutase, glutathione (GSH) peroxidase (GSH-Px), and reduced GSH, were significantly higher in the Mol-treated and Mol pre-treated groups. Catalase (CAT) levels were elevated in all Mol-treated groups, but only in that group were CAT levels statistically significantly higher than in the control group.ConclusionOur results suggest that some oxidant levels could increase following Mtx administration in the liver, possibly contributing to liver damage, whereas Mol could mitigate the histopathological and biochemical effects of hepatotoxicity. However, molecular studies are required to understand the exact mechanisms of these alterations.

Zinc Chloride Exposure Inhibits Brain Acetylcholine Levels, Produces Neurotoxic Signatures, and Diminishes Memory and Motor Activities in Adult Zebrafish.

In this study, we evaluated the acute (24, 48, 72, and 96 h) and chronic (21 days) adverse effects induced by low doses (0.1, 0.5, 1, and 1.5 mg/L) of zinc chloride (ZnCl2) exposure in adult zebrafish by using behavioral endpoints like three-dimensional (3D) locomotion, passive avoidance, aggression, circadian rhythm, and predator avoidance tests. Also, brain tissues were dissected and subjected to analysis of multiple parameters related to oxidative stress, antioxidant responses, superoxide dismutase (SOD), neurotoxicity, and neurotransmitters. The results showed that ZnCl2-exposed fishes displayed decreased locomotor behavior and impaired short-term memory, which caused an Alzheimer’s Disease (AD)-like syndrome. In addition, low concentrations of ZnCl2 induced amyloid beta (amyloid β) and phosphorylated Tau (p-Tau) protein levels in brains. In addition, significant induction in oxidative stress indices (reactive oxygen species (ROS) and malondialdehyde (MDA)), reduction in antioxidant defense system (glutathione (GSH), GSH peroxidase (GSH-Px) and SOD) and changes in neurotransmitters were observed at low concentrations of ZnCl2. Neurotoxic effects of ZnCl2 were observed with significant inhibition of acetylcholine (ACh) activity when the exposure dose was higher than 1 ppm. Furthermore, we found that zinc, metallothionein (MT), and cortisol levels in brain were elevated compared to the control group. A significantly negative correlation was observed between memory and acetylcholinesterase (AChE) activity. In summary, these findings revealed that exposure to ZnCl2 affected the behavior profile of zebrafish, and induced neurotoxicity which may be associated with damaged brain areas related to memory. Moreover, our ZnCl2-induced zebrafish model may have potential for AD-associated research in the future.

Regulatory crosstalk between the oxidative stress-related transcription factor Nfe2l2/Nrf2 and mitochondria

Mitochondria play essential roles in cellular bioenergetics, biosynthesis, and apoptosis. During the process of respiration and oxidative phosphorylation, mitochondria utilize oxygen to generate ATP, and at the same time, there is an inevitable generation of reactive oxygen species (ROS). As excess ROS create oxidative stress and damage cells, the proper function of the antioxidant defense system is critical for eukaryotic cell survival under aerobic conditions. Nuclear factor, erythroid 2-like 2 (Nfe2l2/Nrf2) is a master transcription factor for regulating basal as well as inducible expression of multiple antioxidant proteins. Nrf2 has been involved in maintaining mitochondrial redox homeostasis by providing reduced forms of glutathione (GSH); the reducing cofactor NADPH; and mitochondrial antioxidant enzymes such as GSH peroxidase 1, superoxide dismutase 2, and peroxiredoxin 3/5. In addition, recent research advances suggest that Nrf2 contributes to mitochondrial regulation through more divergent intermolecular linkages. Nrf2 has been positively associated with mitochondrial biogenesis through the direct upregulation of mitochondrial transcription factors and is involved in the mitochondrial quality control system through mitophagy activation. Moreover, several mitochondrial proteins participate in regulating Nrf2 to form a reciprocal regulatory loop between mitochondria and Nrf2. Additionally, Nrf2 modulation in cancer cells leads to changes in the mitochondrial respiration system and cancer bioenergetics that overall affect cancer metabolism. In this review, we describe recent experimental observations on the relationship between Nrf2 and mitochondria, and further discuss the effects of Nrf2 on cancer mitochondria and metabolism.

Effects of constant or intermittent high temperature on egg production, feed intake, and hypothalamic expression of antioxidant and pro-oxidant enzymes genes in laying ducks.

Heat stress is a major environmental factor contributing to lower production of poultry. The objective of present study was to evaluate the influence of constant or intermittent high temperature on the production performance and redox status of plasma and hypothalamus in laying ducks. A total of 288 weight- and laying-matched laying ducks were randomly assigned to 1 of 4 treatments (each with 6 replicates of 12 birds): control, pair-fed, constant high temperature (24 h, 34 ± 1°C), and intermittent high temperature (10 h, 34 ± 1°C). Blood and hypothalamic tissue samples were collected on days 1, 21, and 55 to determine redox status. Average daily feed intake and egg weight was reduced (P < 0.001) during imposition of both high-temperature treatments but was not different (P > 0.05) among the treatments during the recovery period. Lower (P < 0.05) egg mass was observed in pair-fed and intermittent high-temperature treatment during high-temperature period and in constant high temperature during the recovery period. Haugh units from high temperature-treated ducks were significantly lower than those from control or pair-fed ducks (P < 0.05) during the high-temperature period. Both models of heat exposure decreased plasma concentrations of glutathione (GSH) at day 1, and constant high temperature decreased plasma activity of GSH peroxidase (GSH-PX) at day 21 (P < 0.05). Hypothalamic expression of antioxidant genes GSH reductase (GR) and mitochondrial NADH dehydrogenase subunit (Complex Ι) were decreased by both high-temperature treatments at day 1. Hypothalamic expression of genes for pro-oxidant enzymes cyclooxygenase-2 (COX-2), 5-lipoxygenase (5-LOX), and cytochrome P450 7A1 (CYP7A1) were decreased (P < 0.05) by both models of high temperature but transcripts of cyclooxygenase-1 (COX-1) of ducks that were pair-fed or were exposed to constant high temperature were increased at day 21. The transcripts of NADPH oxidase 1 (NOX-1) were decreased at day 1 by both high-temperature treatments (P < 0.05) but increased during the recovery period. These results indicate that, for laying ducks, intermittent high temperature caused much greater negative production performance effects than constant high temperature during high-temperature period, but laying ducks exposed to constant high temperature tend to take longer to recover their production performance. High-temperature stress, either constant or intermittent, altered hypothalamic expression of antioxidation and pro-oxidation genes.

BISPHENOL A DOSE- AND TIME-DEPENDENTLY INDUCES OXIDATIVE STRESS IN RAT LIVER MITOCHONDRIA EX VIVO

Objective: The probable toxic effects of bisphenol A (BPA) on different physiological functions have been reported in animal models. The role of BPA in mitochondrial oxidative stress has not been reported till date. The present study is aimed to elucidate dose- and time-dependent oxidative stress generation by BPA, respectively, in rat liver mitochondria in ex vivo model. Methods: The incubation mixture of BPA-treated groups containing mitochondria, 50 mM potassium phosphate buffer (pH 7.4), and different concentrations of BPA (20–160 μM/ml) (dissolved in 12% DMSO) in a final volume of 1.0 ml was incubated at 37°C in incubator for different time durations (30 min–2 h). Whereas, the incubation mixture of control group contained DMSO (12%), mitochondria and 50 mM potassium phosphatebuffer (pH 7.4).’ will be replaced by ‘Whereas, the incubation mixture of control group contained the same constituents except BPA. Result: We have observed significant decrease in mitochondrial intactness incubated with BPA in dose- and time-dependent manner under bright field and confocal microscopic study compared to control. Further, we have observed a decrease in mitochondrial reduced glutathione (GSH) content and increase in lipid peroxidation and protein carbonylation levels in dose- and time-dependent manner in BPA-exposed mitochondria. We have found a significant increase in the activity of Mn-superoxide dismutase and decrease in the activities of GSH peroxidase, GSH reductase, pyruvate dehydrogenase, and other three enzymes of Kreb’s cycle dose and time dependently in BPA-exposed mitochondria. The results indicate that exposure to BPA leads to decrease in intactness of mitochondria and increase in oxidative stress in mitochondria isolated from rat liver in a dose- and time-dependent manner. Conclusion: It can be concluded that the incubation of mitochondria isolated from rat liver with BPA, caused oxidative stress-mediated damages in mitochondria in both dose- and time-dependent manners.

Fumonisin B1 exposure increases Hsp70 expression in the lung and kidney of rats without inducing significant oxidative stress.

The objective of this experiment was to determine whether fumonisin B1 (FB1) added to the diet of rats in a dose of 50 mg/kg changes the production of heat shock protein 70 (Hsp70) in the lungs and kidney of rats. We also studied the effect of this mycotoxin on the antioxidant system of the body. Mature (8 weeks old) male Wistar Crl:WI BR rats (n = 6/group) were fed the toxin-containing diet for 5 days. FB1 resulted in a 7% body weight reduction without significantly changing the feed intake. Western blot analysis of the lungs and kidney demonstrated a substantial (1.4-fold and 1.8-fold, respectively) increase in Hsp70 expression. Alterations could not be detected in the clinical chemical parameters (total protein, albumin, total cholesterol, glucose, creatinine and urea concentrations, and aspartate aminotransferase activity). There was no statistically significant change in malondialdehyde concentrations and the measured antioxidant parameters (the amount of reduced glutathione, GSH and glutathione peroxidase activity, GPx) in the blood plasma, lung and kidney tissue. Thus, it can be concluded that FB1 did not induce oxidative stress in the lungs and kidney, but increased Hsp70 production.

Role of GPx3 in PPARγ-induced protection against COPD-associated oxidative stress

Cigarette smoke, a source of numerous oxidants, produces oxidative stress and exaggerated inflammatory responses that lead to irreversible lung tissue damage. It is the single, most significant risk factor for chronic obstructive pulmonary disease (COPD). Although an intrinsic defense system that includes both enzymatic and non-enzymatic modulators exists to protect lung tissues against oxidative stress, impairment of these protective mechanisms has been demonstrated in smokers and COPD patients. The antioxidant enzyme GSH peroxidase (GPx) is an important part of this intrinsic defense system. Although cigarette smoke has been shown to downregulate its expression and activity, the underlying mechanism is not known. Peroxisome proliferator-activated receptor γ (PPARγ) is a nuclear hormone receptor with antioxidant effects. PPARγ activation has demonstrated protective effects against cigarette smoke-induced oxidative stress and inflammation. Molecular mechanisms for PPARγ’s antioxidant function likewise remain to be elucidated. This study explored the link between PPARγ and GPx3 and found a positive association in cigarette smoke extract (CSE)-exposed human bronchial epithelial cells. Moreover, we provide evidence that identifies GPx3 as a PPARγ transcriptional target. Attenuation of antioxidant effects in the absence of GPx3 highlights the antioxidant's prominent role in mediating PPARγ’s function. We also demonstrate that ligand-mediated PPARγ activation blocks CSE-induced reactive oxygen species and hydrogen peroxide production via upregulation of GPx3. In summary, our findings describing the molecular mechanisms involving GPx3 and PPARγ in CSE-induced oxidative stress and inflammation may provide valuable information for the development of more effective therapeutics for COPD.

Cell clustering mediated by the adhesion protein PVRL4 is necessary for α6β4 integrin–promoted ferroptosis resistance in matrix-detached cells

Ferroptosis is an iron-dependent form of programmed cell death characterized by the accumulation of lipid-targeting reactive oxygen species that kill cells by damaging their plasma membrane. The lipid repair enzyme GSH peroxidase 4 (GPX4) protects against this oxidative damage and enables cells to resist ferroptosis. Recent work has revealed that matrix-detached carcinoma cells can be susceptible to ferroptosis and that they can evade this fate through the signaling properties of the α6β4 integrin, which sustains GPX4 expression. Although these findings on ferroptosis are provocative, they differ from those in previous studies indicating that matrix-detached cells are prone to apoptosis via a process referred to as anoikis. In an effort to reconcile these discrepant findings, here we observed that matrix-detached epithelial and carcinoma cells cluster spontaneously via a mechanism that involves the cell adhesion protein PVRL4 (also known as Nectin-4). We found that this clustering process allows these cells to survive by stimulating a PVRL4/α6β4/Src signaling axis that sustains GPX4 expression and buffers against lipid peroxidation. In the absence of α6β4, PVRL4-mediated clustering induced an increase in lipid peroxidation that was sufficient for triggering ferroptosis. When the clustering was inhibited, single cells did not exhibit a significant increase in lipid peroxidation in the absence of α6β4, and they were more susceptible to apoptosis than to ferroptosis. These results indicate that ferroptosis induction depends on cell clustering in matrix-detached cells that lack α6β4 and imply that the fate of matrix-detached cells can be determined by the state of their cell-cell interactions.

Cellular and molecular responses to acute cocaine treatment in neuronal-like N2a cells: potential mechanism for its resistance in cell death

Cocaine is a highly abused drug that causes psychiatric and neurological problems. Its entry into neurons could alter cell-biochemistry and contribute in the manifestation of early pathological symptoms. We have previously shown the acute cocaine effects in rat C6 astroglia-like cells and found that these cells were highly sensitive to cocaine in terms of manifesting certain pathologies known to underlie psychological disorders. The present study was aimed to discern acute cocaine effects on the early onset of various changes in Neuro-2a (N2a) cells. Whole-cell patch-clamp recording of differentiated cells displayed the functional voltage-gated Na+ and K+ channels, which demonstrated the neuronal characteristics of the cells. Treatment of these cells with acute cocaine (1 h) at in vivo (nM to μM) and in vitro (mM) concentrations revealed that the cells remained almost 100% viable. Cocaine administration at 6.25 μM or 4 mM doses significantly reduced the inward currents but had no significant effect on outward currents, indicating the Na+ channel-blocking activity of cocaine. While no morphological change was observed at in vivo doses, treatment at in vitro doses altered the morphology, damaged the neurites, and induced cytoplasmic vacuoles; furthermore, general mitochondrial activity and membrane potential were significantly decreased. Mitochondrial dysfunction enabled the cells switch to anaerobic glycolysis, evidenced by dose-dependent increases in lactate and H2S, resulting unaltered ATP level in the cells. Further investigation on the mechanism of action unfolded that the cell’s resistance to cocaine was through the activation of nuclear factor E2-related factor-2 (Nrf-2) gene and subsequent increase of antioxidants (glutathione [GSH], catalase and GSH peroxidase [GPx]). The data clearly indicate that the cells employed a detoxifying strategy against cocaine. On a broader perspective, we envision that extrapolating the knowledge of neuronal resistance to central nervous system (CNS) diseases could delay their onset or progression.

Embelin inhibits abdominal aortic aneurysm through decreasing IL‑6‑induced STAT3 and NF‑κB inactivation.

The aim of the present study was to investigate the effect of embelin on abdominal aortic aneurysm (AAA). AAA model mice were induced by chronic infusion of 1,000ng/kg/min Angiotensin II. AAA model mice were treated with 25, 50 or 100mg/kg embelin for 28days. Embelin inhibited tumor necrosis factor‑α, interleukin (IL)‑1β, IL‑6, IL‑18 and malondialdehyde (MDA) level activities, increased superoxide dismutase, glutathione (GSH) and GSH peroxidase level activities and inhibited MDA level activities in AAA mice Embelin suppressed the secretion of matrix metalloproteinase‑9 protein expression, monocyte chemoattractant protein‑2 activity and epithelial neutrophil‑activating peptide expression levels in AAA mice. Embelin suppressed phosphorylated‑signal transducer and activator of transcription (STAT) 3, phosphorylated‑p38 mitogen‑activated protein kinase and nuclear factor (NF)‑κB protein expression in AAA mice. These findings indicate that embelin inhibits AAA through decreasing IL‑6‑induced STAT3, and NF‑κB inactivation.

The effects of hyperoxia liquid regulate cardiopulmonary bypass‑induced myocardial damage through the Nrf2‑ARE signaling pathway

The aim of the present study was to investigate the protective role of hyperoxia liquid in regulating cardiopulmonary bypass (CPB)‑induced myocardial damage and its possible underlying mechanism. In the CPB‑induced rat model, hyperoxia liquid enhanced left ventricular ejection fraction (LVEF), reduced the left ventricular internal dimension systole (LVIDs) level, inhibited malondialdehyde levels, increased superoxide dismutase, glutathione (GSH) and GSH peroxidase levels, suppressed heart cell apoptosis, and induced the nuclear factor erythroid 2‑related factor 2 (Nrf2) and heme oxygenase‑1 (HO‑1) signaling pathway. Then, ML385, a Nrf2 inhibitor, was used to attenuate the effect of hyperoxia liquid on LVEF and LVIDs levels, oxidative stress and heart cell apoptosis in the CPB‑induced rat model. Collectively, the results of the present study demonstrated that the protective role of hyperoxia liquid may regulate oxidative stress in a CPB‑induced rat model through the Nrf2‑antioxidant response element signaling pathway.

Modulatory effects of some natural products on hepatotoxicity induced by combination of sodium valproate and paracetamol in rats.

Possible hepatoprotective effect of Curcuma longa and/or Nigella sativa against hepatotoxicity induced by coadministration of sodium valproate (SV) and paracetamol was studied. Rats were divided into 10 groups, control groups 1, 2, 3, and 4 received vehicles, C. longa (200mg/kg, p.o.), N. sativa (250mg/kg, p.o.), or both herbs for 21days, respectively. Toxicity groups 5, 6, and 7 received SV (300mg/kg, i.p.), paracetamol (1000mg/kg, p.o.) for the last 4days or both for 21days, respectively. Protection groups 8, 9, and 10 received C. longa, N. sativa, or both, respectively, 1h before the administration of both the drugs for 21days. SV and/or paracetamol significantly increased aspartate aminotransferase (AST), alanine aminotransferase (ALT), alkaline phosphatase (ALP), total bilirubin, relative liver/body weight ratio, malondialdehyde (MDA), tumor necrosis factor alpha (TNF-α), and caspase-3 (Casp-3) while significantly decreased albumin, total protein, glutathione (GSH) reduced, GSH peroxidase, and superoxide dismutase (SOD). Preadministration of C. longa and/or N. sativa caused protective effect against the hepatotoxicity induced by both drugs.