Glutathione Replenishment Research Articles

441 Transcriptomic analysis of Influenza A infected lung organoids reveals Warburg-like phenotype

OBJECTIVES/GOALS: The CDC estimates that Influenza infections account for an average of 420,000 hospitalizations and 34,700 deaths in the U.S. each year. This project explores the underlying mechanisms of the infectious process of Influenza A in human lung organoids by examining the differential transcriptomic expression compared to uninfected controls. METHODS/STUDY POPULATION: Lung organoids were cultured from differentiated human bronchial epithelial cells from lung transplant donors on an air-liquid interface until they were confirmed to contain both mucous producing and ciliated cells. Lung organoids are ideal models in translational science due to their structural and functional characteristics which closely mimic those of in vivo human epithelial tissue. Half the organoids were exposed to Influenza A pH1N1 for 72h; the other half served as uninfected controls. RNA was isolated from both groups and sequenced using the Oxford Nanopore MinION which generates full length reads. Reads were aligned to the human reference genome (GRCh38.p14) using Minimap2. RESULTS/ANTICIPATED RESULTS: The MinION sequenced an average of 3.24m reads per sample and a total of 13,128 genes were relevantly expressed (defined as greater than 1 read per million in at least half the samples). ANOVA with a 5% false discovery rate (Benjamini and Hochberg correction) revealed 5,417 differentially expressed genes between infected and control groups. Within this subset, we identified downregulation of mucociliary clearance, mitochondrial and ß-oxidation, peroxisome, and glutathione replenishment genes. We further identified upregulation in inflammatory markers, lactate dehydrogenase enzymes, and several s100 proteins. The downregulation of mitochondrial and β-oxidation markers and the upregulation of lactate dehydrogenase enzymes revealed a Warburg-like phenotype which has not previously been reported. DISCUSSION/SIGNIFICANCE: This study reveals a novel Warburg-like phenotype in Influenza A infection alongside downregulated mucociliary clearance and upregulated inflammatory processes. These findings improve our understanding of Influenza A infection and point to potential therapeutic targets to advance precision medicine approaches to treatment.

Elevated ROS levels during the early development of Angelman syndrome alter the apoptotic capacity of the developing neural precursor cells

Angelman syndrome (AS) is a rare genetic neurodevelopmental disorder caused by the maternally inherited loss of function of the UBE3A gene. AS is characterized by a developmental delay, lack of speech, motor dysfunction, epilepsy, autistic features, happy demeanor, and intellectual disability. While the cellular roles of UBE3A are not fully understood, studies suggest that the lack of UBE3A function is associated with elevated levels of reactive oxygen species (ROS). Despite the accumulating evidence emphasizing the importance of ROS during early brain development and its involvement in different neurodevelopmental disorders, up to date, the levels of ROS in AS neural precursor cells (NPCs) and the consequences on AS embryonic neural development have not been elucidated. In this study we show multifaceted mitochondrial aberration in AS brain-derived embryonic NPCs, which exhibit elevated mitochondrial membrane potential (ΔΨm), lower levels of endogenous reduced glutathione, excessive mitochondrial ROS (mROS) levels, and increased apoptosis compared to wild-type (WT) littermates. In addition, we report that glutathione replenishment by glutathione-reduced ethyl ester (GSH-EE) corrects the excessive mROS levels and attenuates the enhanced apoptosis in AS NPCs. Studying the glutathione redox imbalance and mitochondrial abnormalities in embryonic AS NPCs provides an essential insight into the involvement of UBE3A in early neural development, information that can serve as a powerful avenue towards a broader view of AS pathogenesis. Moreover, since mitochondrial dysfunction and elevated ROS levels were associated with other neurodevelopmental disorders, the findings herein suggest some potential shared underlying mechanisms for these disorders as well.

X-linked genodermatoses from diagnosis to tailored therapy.

Genodermatoses are rare heterogeneous genetic skin diseases with multiorgan involvement. They severely impair an individual's well-being and can also lead to early death. During the progress of this review, we have implemented a targeted research approach, diligently choosing the most relevant and exemplary articles within the subject matter. Our method entailed a systematic exploration of the scientific literature to ensure a compre-hensive and accurate compilation of the available sources. Among genodermatoses, X-linked ones are of particular importance and should always be considered when pediatric males are affected. Regardless of other syndromic forms without prevalence of skin symptoms, X-linked genodermatoses can be classified in three main groups: keratinization defects, pigmentation defects, and inflammatory skin diseases. Typical examples are dyskeratosis congenita, keratosis follicularis spinulosa decalvans, hypohidrotic ectodermal dysplasia, chondrodysplasia punctata, hypohidrotic ectodermal dysplasia, incontinentia pigmenti, chronic granulomatous disease, CHILD syndrome and ichthyosis. In this field, genetic diagnosis of the specific disease is important, also considering that numerous clinical trials of orphan drugs and genetic therapies are being proposed for these rare genetic diseases. Thus, this chapter starts from clinical to molecular testing and ends with a review of all clinical trials on orphan drugs and gene therapy for genodermatoses.

Baicalein inhibits cell proliferation and enhances apoptosis in human A549 cells and benzo(a)pyrene‐induced pulmonary carcinogenesis in mice

Our current study is done to explore the possible mechanisms to elaborate on the growth inhibitory effect of baicalein (BE) in human lung carcinoma. Initially, BE (25 and 50 µM) treatment for 24 h, suppressedthe viability and inhibited population growth in A549 cells. BE upholds the production of reactive oxygen species (ROS) with concomitant replenishment of glutathione, catalase, and glutathione peroxidase activity. The expression level of nuclear factor erythroid 2-related factor 2and heme oxygenase-1markedly increased after BE treatment will intimidate A549 cells proliferation by the ROS-independent pathway via the antioxidant pathway. In vivo investigations were carried out on BE (12 mg/kg, oral) in benzo(a)pyrene (B(a)P; 50 mg/kg, oral) induced lung carcinogenesis in mice. BE induces caspase-dependent apoptosis by increasing the levels of cytosolic cytochrome c accompanied by upregulating the outflow of p53, Bax, and caspase-3 with a concomitant abatement in the outflow of Bcl-2 in both in vitro and in vivo. In the murine model, BE treatment hindered the countenance of proliferation-related proteins (argyrophilic nucleolar organizing regions and proliferating cell nuclear antigen). Additionally, appraisal of the cell nucleus by transmission electron microscopic assessment uncovered that BE treatment adequately counteracts B(a)P-induced lung cancer cell survival. During the transition of the G0 /G1 phase, BE is arrested in the cell cycle process. This might be the cause of a substantial increase in the appearance of p21Cip1 with concomitant downregulating the expressions of CDK4, cyclin D, and cyclin E both in vitro and in vivo. Our results conclude that BE treatment induced apoptosis and repressed proliferation both in vitro and in vivo of human lung carcinoma.

The Benevolent Bile: Bile Acids as Stimulants of Liver Regeneration

The Benevolent Bile: Bile Acids as Stimulants of Liver Regeneration

Lipid peroxidation aggravates anti-tuberculosis drug-induced liver injury: Evidence of ferroptosis induction

Anti-tuberculosis drug-induced liver injury (ATB-DILI) is a common adverse reaction of anti-tuberculosis drug treatment. Studies have shown that isoniazid (INH) and rifampicin (RFP) are mainly metabolized in the liver and a large amount of intracellular glutathione is used up during the metabolism of these drugs, resulting in lipid peroxidation and hepatocyte death. Ferroptosis is a novel form of programmed cell death caused by iron-ion-dependent lipid peroxidation. In this study, we explored lipid peroxidation and ferroptosis during ATB-DILI. Morphology of ferroptosis was discovered in ATB-DILI mouse livers by transmission electron microscopy. Flow cytometry was used to assess the molecular markers of lipid peroxidation and ferroptosis including reactive oxygen species, lipid peroxidation, and cellular iron content. Glutathione peroxidase 4 (GPX4) was depleted, while acyl-CoA synthetase long chain family member 4 (ACSL4) was overexpressed in the ATB-DILI tissues. And glutathione supplementation significantly reduced the level of lipid peroxidation and the risk of liver damage. Retrospective study of tuberculosis patients who underwent INH and RFP treatment also revealed an association between the intake of glutathione and a negative ATB-DILI rate. In addition, iron supplementation enhanced the degree of lipid peroxidation and liver injury induced by INH and RFP in vivo and clinical retrospective study. Taken together, these results indicate that lipid peroxidation and evidence suggestive of ferroptosis occurs during ATB-DILI, and glutathione replenishment prevents this process while iron supplementation augmenting this effect.

The gastroprotective effect of obestatin on indomethacin-induced acute ulcer is mediated by a vagovagal mechanism.

In order to investigate the role of the vagus nerve in the possible gastroprotective effect of obestatin on the indomethacin-induced acute oxidative gastric injury, Sprague-Dawley rats of both sexes were injected subcutaneously with indomethacin (25 mg/kg, 5% NaHCO3) followed by obestatin (10, 30 or 100 μg/kg). In other sets of rats, surgical vagotomy (Vx) or selective degeneration of vagal afferent fibers by perivagal capsaicin was performed before the injections of indomethacin or indomethacin + obestatin (30 μg/kg). Gastric serosal blood flow was measured, and 4 h after ulcer induction gastric tissue samples were taken for histological and biochemical assays. Obestatin reduced the severity of indomethacin-induced acute ulcer via the reversal of reactive hyperemia, by inhibiting ulcer-induced neutrophil infiltration and lipid peroxidation along with the replenishment of glutathione (GSH) stores, whereas Vx abolished the inhibitory effect of obestatin on blood flow and lipid peroxidation, and worsened the severity of ulcer. On the other hand, serosal blood flow was even amplified by the selective denervation of the capsaicin-sensitive vagal afferent fibers, but obestatin-induced reduction in ulcer severity was not altered. In conclusion, the gastroprotective effect of obestatin on indomethacin-induced ulcer appears to involve the activation of the vagovagal pathway.

N-acetylcysteine inhibits thrombosis in a murine model of myeloproliferative neoplasm

AbstractThrombosis is a major cause of mortality in patients with myeloproliferative neoplasms (MPNs), though there is currently little to offer patients with MPN beyond aspirin and cytoreductive therapies such as hydroxyurea for primary prevention. Thrombogenesis in MPN involves multiple cellular mechanisms, including platelet activation and neutrophil-extracellular trap formation; therefore, an antithrombotic agent that targets one or more of these processes would be of therapeutic benefit in MPN. Here, we treated the JAK2V617F knockin mouse model of polycythemia vera with N-acetylcysteine (NAC), a sulfhydryl-containing compound with broad effects on glutathione replenishment, free radical scavenging, and reducing disulfide bonds, to investigate its antithrombotic effects in the context of MPN. Strikingly, NAC treatment extended the lifespan of JAK2V617F mice without impacting blood counts or splenomegaly. Using an acute pulmonary thrombosis model in vivo, we found that NAC reduced thrombus formation to a similar extent as the irreversible platelet inhibitor aspirin. In vitro analysis of platelet activation revealed that NAC reduced thrombin-induced platelet-leukocyte aggregate formation in JAK2V617F mice. Furthermore, NAC reduced neutrophil extracellular trap formation in primary human neutrophils from patients with MPN as well as healthy controls. These results provide evidence that N-acetylcysteine inhibits thrombosis in JAK2V617F mice and provide a pre-clinical rationale for investigating NAC as a therapeutic to reduce thrombotic risk in MPN.

Protective Effect of Tamarind Seed Coat Ethanol Extract on Eryptosis Induced by Oxidative Stress.

Suicidal erythrocyte death, or eryptosis, is the key event in eliciting anemia in numerous pathological conditions, including diabetes, chronic kidney disease, cancer, sepsis, etc. Oxidative stress is an important trigger in the acceleration of erythrocyte loss via eryptosis and an underlying mechanism of anemia emergence in the above pathologies. Therefore, there is an increasing demand for identification of antioxidants and anti-eryptotic agents for the management of stress-related ailments. Here, we demonstrated the antioxidant and anti-eryptotic properties of the tamarind seed coat ethanol extract (TSCEE) against 2,2'-azobis(2-amidinopropane) dihydrochloride (AAPH)-induced oxidative stress and eryptosis. The presence of probable secondary metabolites in the TSCEE extract was investigated by RP-HPLC. Active groups present in the TSCEE were studied by the Fourier-transform infrared spectroscopy. Cyclic voltammetric studies confirmed the antioxidant potential of TSCEE. The protective effect of TSCEE on red blood cells was confirmed by assessing various eryptotic markers, such as reactive oxygen species generation, intracellular calcium levels, and phosphatidylserine exposure. TSCEE reduced lipid peroxidation and protein carbonyl content and restored the levels of glutathione, antioxidant enzymes, and enzymes involved in glutathione replenishment. In conclusion, TSCEE was found to exhibit multiple therapeutic properties, which makes it a promising agent for treating oxidative stress-induced eryptosis and subsequent anemia in various pathologies.

N-acetyl-cysteine in Schizophrenia: Potential Role on the Sensitive Cysteine Proteome.

N-acetyl-cysteine (NAC) has shown widespread utility in different psychiatric disorders, including a beneficial role in schizophrenic patients. Although the replenishment of glutathione and the antioxidant activity of NAC have been suggested as the mechanisms that improve such a wide range of disorders, none seems to be sufficiently specific to explain these intriguing effects. A sensitive cysteine proteome is emerging as a functional and structural network of interconnected Sensitive Cysteine-containing Proteins (SCCPs) that together with reactive species and the cysteine/ glutathione cycles can regulate the bioenergetic metabolism, the redox homeostasis and the cellular growth, differentiation and survival, acting through different pathways that are regulated by the same thiol radical in cysteine residues. Since this sensitive cysteine network has been implicated in the pathogenesis of Parkinson's and Alzheimer's diseases, I have reviewed if the proteins that play a role in schizophrenia can be classified as SCCPs. The results show that the principal proteins playing a role in schizophrenia can be classified as SCCPs, suggesting that the sensitive cysteine proteome (cysteinet) is defective in this type of psychosis. The present review proposes that there is a deregulation of the sensitive cysteine proteome in schizophrenia as the consequence of a functional imbalance among different SCCPs, which play different functions in neurons and glial cells. In this context, the role of NAC to restore and prevent schizophrenic disorders is discussed.

Sources and toxicological effects of lead on human health

Lead toxicity is one of the most hazardous metal toxicities. It can enter the body through lead-based paint, dust, water, soil, tableware, and folk medicines. Children are especially prone to develop lead toxicity. Lead acts by inducing oxidative stress due to inefficient replenishment of glutathione. Lead can also cause hemolytic anemia due to disruption of the cellular membrane by lipid peroxidation. Lead toxicity also affects neurotransmitter levels and causes severe health issues related to organ damage, some even leading to death. The main aim of this review article is to summarize lead toxicity detection, its sources, and its mechanism including various toxicological effects on human health. It also focuses on the prevention and treatment of lead toxicity.

Whey protein concentrate supplementation protects erythrocyte membrane from aging‐induced alterations in rats

Whey protein concentrate (WPC), a protein complex derived from milk, exerts a number of health benefits. The present study deals with the beneficial effects of WPC on erythrocyte membrane in rats during aging. Male Wistar rats of two different age groups: young (4 months) and old (24 months) were supplemented with WPC (300 mg/kg b.w. orally) for 28 days. The effect of WPC on age-dependent activities of membrane transporters: Na+/K+-ATPase, Ca2+ATPase (PMCA), and Na+/H+ Exchanger, and also on markers of oxidative stress: protein carbonyl, lipid hydroperoxides, sialic acid, and total thiol was determined. WPC supplementation ameliorated the age-dependent alteration in the activity of membrane-bound transporters, and biomarkers of oxidative stress in old-aged rats. Thus, WPC could be a useful dietary regimen and may augment the ability of cells to fight damage against age-dependent structural and functional alterations. Practical applications Anti-aging strategies focused on nutritional modulation of health span provide an exciting area of research. Whey protein, a vital constituent of milk is rich in sulfur-containing amino acids and has been widely accepted as an effective and safe cysteine donor for glutathione replenishment. It is acknowledged that biomarkers of oxidative stress provide a useful indicator for assessing age-dependent alterations. Nutritional supplements which augment redox balance provide an effective intervention strategy for age-dependent oxidative damage. In this study, we provide experimental evidence of WPC-induced protective effect on biomarkers of aging in rats. Based on the studies on rats, we hypothesize that similar effect may be obtained in humans. Thus, WPC could be explored as a functional food to boost the cellular antioxidant levels and improve health span in humans.

Abstract 2320: Heme oxygenase-1 mediates ferroptosis

Abstract Ferroptosis is a form of oxidative cell death and has become a chemotherapeutic target for cancer treatment. BAY 11-7085 (BAY), which is a well-known IκBα inhibitor, suppressed viability in cancer cells via induction of ferroptotic death in an NF-κB-independent manner. This study was aimed to characterize the underlying mechanism by BAY and demonstrate its potential chemotherapeutic targets for cancer treatment. Reactive oxygen species scavenging, relief of lipid peroxidation, replenishment of glutathione and thiol-containing agents, as well as iron chelation, rescued BAY-induced cell death in human breast cancer cells (MDA-MB-231 and MDA-MB-468) and glioblastoma cells (DBTRG-05MG). The results from quantitative real-time PCR and western blotting analysis showed that BAY upregulated a variety of nuclear factor-E2-related factor 2 (Nrf2) target genes related to redox regulation, particularly heme oxygenase-1 (HO-1) and solute carrier family 7 membrane 1 (SLC7A11). Studies with pharmacological inhibitors and shRNA interventions suggested that the hierarchy of induction is Nrf2-SLC7A11-HO-1. The ferroptotic process induced by hHO-1 overexpression further indicated that HO-1 is a key mediator of BAY-induced ferroptosis that operates through cellular redox regulation and iron accumulation. Our study discovered that BAY induced ferroptosis via Nrf2-SLC7A11-HO-1 pathway and provided new insights to understand the mechanism of HO-1-induced ferroptosis, suggesting HO-1 as a new chemotherapeutic target for cancer treatment. Citation Format: Shih-Kai Chiang, Shuen-Ei Chen, Ling-Chu Chang. Heme oxygenase-1 mediates ferroptosis [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2018; 2018 Apr 14-18; Chicago, IL. Philadelphia (PA): AACR; Cancer Res 2018;78(13 Suppl):Abstract nr 2320.

N-acetylcysteine in dermatology.

N-acetylcysteine is a mucolytic drug which is commonly used as an antidote for acetaminophen toxicity. It is a thiol compound, which acts as a donor of cysteine, leading to replenishment of glutathione and thus acts as an antioxidant. It also has anti-inflammatory effects, alters the levels of neurotransmitters, inhibits proliferation of fibroblasts and keratinocytes and causes vasodilatation. Due to these actions, n-acetylcysteine has found use in several dermatologic conditions in systemic and topical form. The drug has been used as an adjuvant in the management of conditions such as toxic epidermal necrolysis, drug hypersensitivity syndrome, trichotillomania, skin picking disorders and onychotillomania, ichthyoses, contact dermatitis, atopic dermatitis, melasma, pseudoporphyria, connective tissue diseases, wound healing and alopecia. It also has a role in protection from radiation-induced skin damage including photo-ageing, photocarcinogenesis and radiation dermatitis. Most indications in dermatology are supported by case reports, small case series and small trials. Higher quality of evidence is needed for its wider use. The drug is cheap and is generally safe with few adverse effects. Thus a greater role is possible for use of n-acetylcysteine in various skin conditions. This review explores the various uses of n-acetylcysteine in the field of dermatology, the evidence supporting the same, the possible mechanisms of action and the adverse effects of the drug.

Heme oxygenase-1 mediates BAY 11–7085 induced ferroptosis

Ferroptosis is a form of oxidative cell death and has become a chemotherapeutic target for cancer treatment. BAY 11–7085 (BAY), which is a well-known IκBα inhibitor, suppressed viability in cancer cells via induction of ferroptotic death in an NF-κB-independent manner. Reactive oxygen species scavenging, relief of lipid peroxidation, replenishment of glutathione and thiol-containing agents, as well as iron chelation, rescued BAY-induced cell death. BAY upregulated a variety of Nrf2 target genes related to redox regulation, particularly heme oxygenase-1 (HO-1). Studies with specific inhibitors and shRNA interventions suggested that the hierarchy of induction is Nrf2−SLC7A11−HO-1. SLC7A11 inhibition by erastin, sulfasalazine, or shRNA interference sensitizes BAY-induced cell death. Overexperession of SLC7A11 attenuated BAY-inhibited cell viability. The ferroptotic process induced by hHO-1 overexpression further indicated that HO-1 is a key mediator of BAY-induced ferroptosis that operates through cellular redox regulation and iron accumulation. BAY causes compartmentalization of HO-1 into the nucleus and mitochondrion, and followed mitochondrial dysfunctions, leading to lysosome targeting for mitophagy. In this study, we first discovered that BAY induced ferroptosis via Nrf2−SLC7A11−HO-1 pathway and HO-1 is a key mediator by responding to the cellular redox status.

Prognosis and treatment of FOLFOX therapy related interstitial pneumonia: a plea for multimodal immune modulating therapy in the respiratory insufficient patient

BackgroundThe FOLFOX regimen, i.e., folinic acid (FOL), fluorouracil (F) and oxaliplatin (OX), is a drug cocktail that is used to treat gastric and colorectal cancers. Despite the concomitant improvements in response rate, duration of response and patient survival, reports of serious toxic pulmonary side effects have progressively emerged.Case presentationWe describe a patient who was treated with FOLFOX as an adjuvant to a rectosigmoidal resection of a rectosigmoidal carcinoma and who developed respiratory insufficiency requiring mechanical ventilation. Computed tomography (CT) imaging and open lung biopsy findings were compatible with interstitial pneumonia (IP). She received multimodal combination treatment (acetylcysteine, corticosteroids, immune globulins and cyclophosphamide) and survived.We performed a systematic literature search and reviewed all 45 reported cases of FOLFOX-related lung toxicity and/or pulmonary fibrosis for their clinical characteristics and their outcomes related to therapy.ConclusionsWe found that for the 45 cases with available data, the median age was 70 years, and the male–female ratio was 3.5: 1. In the patients exhibiting only mild respiratory symptoms, discontinuation of the culprit drug (oxaliplatin) resulted in a 100% regression of the symptoms. However the prognosis of the respiratory insufficient patient proved to be grim: death occurred in 76.9% of the cases despite conventional treatment with corticosteroids. We therefore urge oncologists and critical care specialists not to limit their interventions to the discontinuation of chemotherapy, artificial ventilation, corticosteroids and glutathione replenishment and to consider the gradual introduction of additional immune-modulating agents whenever life-threatening respiratory symptoms in oxaliplatin-treated patients do not subside; all the more so considering the fact that our analysis showed that every patient who survived intubation and mechanical ventilation experienced a full clinical recovery.

Modulation of TGF-β/Smad and ERK signaling pathways mediates the anti-fibrotic effect of mirtazapine in mice

Serotonin (5-HT) has been implicated as a key driver of liver fibrosis, acting via 5-HT2 receptor activation in the hepatic stellate cells. The current study was conducted to investigate the effects of mirtazapine, a 5-HT2A antagonist, in a mouse model of liver fibrosis. Mice received thioacetamide (TAA, 150mg/kg/biweekly, ip) for nine successive weeks for induction of liver fibrosis. Administration of mirtazapine significantly improved the plasma aminotransferases, reduced hepatic 5-HT concentration and ameliorated TAA-induced liver fibrosis, as demonstrated by reduced portal blood pressure, liver procollagen I content and α alpha smooth muscle actin expression. Moreover, hepatic collagen deposition was markedly decreased in mirtazapine-treated mice as evaluated by Masson's trichrome staining. Mirtazapine provided an antifibrotic environment by decreasing the liver content of transforming growth factor-β1 (TGF-β1), and protein kinase C as well as the expression of phosphorylated-Smad3 (p-Smad) and phosphorylated extracellular signal-regulated kinases 1 and 2 (p-ERK1/2). Additionally, oxidative stress was largely mitigated by mirtazapine as manifested by decreased liver lipid peroxidation and NADPH oxidase 1 along with glutathione replenishment. The current study indicates that mirtazapine suppressed 5-HT–mediated TGF-β1/Smad3 and ERK1/2 signaling pathways as well as oxidative stress that contribute to the progression of liver fibrosis.

Mechanism of immunoprotective effects of curcumin in DLM-induced thymic apoptosis and altered immune function: an in silico and in vitro study

Curcumin, a main component of Curcuma Longa Linn, is a plant polyphenol used as an immune-enhancer in the Indian system of traditional medicine. However, its underlying mechanism of immune-protection remains unknown. The present study is designed to delineate the role of curcumin in deltamethrin (DLM)-induced thymocyte apoptosis and altered immune functions. In silico studies revealed that curcumin has a strong binding affinity toward CD4 and CD8 receptors. DLM (25 µM) induces thymocytes apoptosis through oxidative stress and caspase-dependent pathways. Various concentrations of curcumin (1, 10 and 50 µg/ml), when added along with DLM, caused a concentration- and time-related amelioration in apoptogenic signaling pathways induced by DLM. Inhibition of DLM-induced reactive oxygen species production, replenishment of glutathione and suppression of caspase activities by curcumin may thus be responsible for the suppression of downstream cascade of events, i.e. apoptosis, phenotypic changes and altered cytokine release. Thus, this study clearly demonstrates that the mechanism of immunoprotection of curcumin in DLM-induced thymic apoptosis includes inhibition of oxidative stress and caspase-dependent pathways underlying apoptosis.

Effects of Enzyme Induction and/or Glutathione Depletion on Methimazole-Induced Hepatotoxicity in Mice and the Protective Role of N-Acetylcysteine.

Methimazole is the most convenient drug used in the management of hyperthyroid patients. However, associated with its clinical use is hepatotoxicity as a life threatening adverse effect. The exact mechanism of methimazole-induced hepatotoxicity is still far from clear and no protective agent has been developed for this toxicity. This study attempts to evaluate the hepatotoxicity induced by methimazole at different experimental conditions in a mice model. Methimazole-induced hepatotoxicity was investigated in different situations such as enzyme induced and/or glutathione depleted animals. Methimazole (100 mg/kg, i.p) administration caused hepatotoxicity as revealed by increase in serum alanine aminotransferase (ALT) activity as well as pathological changes of the liver. Furthermore, a significant reduction in hepatic glutathione content and an elevation in lipid peroxidation were observed in methimazole-treated mice. Combined administration of L-buthionine sulfoximine (BSO), as a glutathione depletory agent, caused a dramatic change in methimazole-induced hepatotoxicity characterized by hepatic necrosis and a severe elevation of serum ALT activity. Enzyme induction using phenobarbital and/or β-naphtoflavone beforehand, deteriorated methimazole-induced hepatotoxicity in mice. N-acetyl cysteine (300 mg/kg, i.p) administration effectively alleviated hepatotoxic effects of methimazole in both glutathione-depleted and/or enzyme induced animals. The severe hepatotoxic effects of methimazole in glutathione-depleted animals, reveals the crucial role of glutathione as a cellular defense mechanism against methimazole-induced hepatotoxicity. Furthermore, the more hepatotoxic properties of methimazole in enzyme-induced mice, indicates the role of reactive intermediates in the hepatotoxicity induced by this drug. The protective effects of N-acetylcysteine could be attributed to its radical/reactive metabolite scavenging, and/or antioxidant properties as well as glutathione replenishment activities.

Redox-dependent increases in glutathione reductase and exercise preconditioning: role of NADPH oxidase and mitochondria

We have previously shown that exercise leads to sustainable cardioprotection through a mechanism involving improved glutathione replenishment. This study was conducted to determine if redox-dependent modifications in glutathione reductase (GR) were involved in exercise cardioprotection. Furthermore, we sought to determine if reactive oxygen species generated by NADPH oxidase and/or mitochondria during exercise were triggering events for GR modulations. Rats were exercised for 10 consecutive days, after which isolated hearts were exposed to ischaemia/reperfusion (25 min/120 min). Exercise protected against infarction and arrhythmia, and preserved coronary flow. The GR inhibitor BCNU abolished the beneficial effects. GR activity was increased following exercise in a redox-dependent manner, with no change in GR protein levels. Because fluorescent labelling of GR protein thiols showed lower amounts of reduced thiols after exercise, we sought to determine the source of intracellular reactive oxygen species that may be activating GR. Subsets of animals were exercised immediately after treatment with either NADPH-oxidase inhibitors apocynin or Vas2870, or with mitoTEMPO or Bendavia, which reduce mitochondrial reactive oxygen species levels. The cardioprotective effects of exercise were abolished if animals exercised in the presence of NADPH oxidase inhibitors, in clear contrast to the mitochondrial reagents. These changes correlated with thiol-dependent modifications of GR. Adaptive cardioprotective signalling is triggered by reactive oxygen species from NADPH oxidase, and leads to improved glutathione replenishment through redox-dependent modifications in GR.