Glutathione Antioxidant System Research Articles

Beyond Redox Regulation: Novel Roles of TXNIP in the Pathogenesis and Therapeutic Targeting of Kidney Disease.

Cellular stress conditions, such as oxidative and endoplasmic reticulum (ER) stresses contribute to development of various kidney diseases. Oxidative stress is prompted by reactive oxygen species (ROS) accumulation and delicately mitigated by glutathione and thioredoxin (Trx) antioxidant systems. Initially identified as a Trx-binding partner, thioredoxin interacting protein (TXNIP) is significantly upregulated and activated by oxidative and ER stresses. The function of TXNIP is closely linked to its subcellular localizations. Under normal physiological conditions, TXNIP primarily localizes to the nucleus. When exposed to ROS or ER stress, TXNIP relocates to mitochondria and binds to mitochondrial Trx2, which releases Trx-tethered apoptosis signal-regulating kinase 1 (ASK1) and activates ASK1-mediated apoptosis. Oxidative and ER stresses are also closely associated with autophagy. TXNIP can promote or inhibit autophagy depending on different contexts. Although recent studies have highlighted the indispensable role of TXNIP in the etiology and progression of kidney disease, TXNIP-targeted therapy is still missing. This review will focus on the following aspects: (1) Oxidative and ER stresses; (2) Regulation and function of TXNIP during cellular stress; (3) TXNIP in stress-regulated autophagy; (4) TXNIP in kidney diseases, including nephrotic syndrome, diabetic nephropathy and chronic kidney disease, acute kidney injury and kidney aging; (5) Novel treatment agents targeting TXNIP in kidney disease, where we will review the current advances in chemical compounds and RNA-based therapy suppressing TXNIP.

The Key Enzymes of Carbon Metabolism and the Glutathione Antioxidant System Protect Yarrowia lipolytica Yeast Against pH-Induced Stress.

In this study, we first thoroughly assayed the response of the key enzymes of energy metabolism and the antioxidant system in Yarrowia lipolytica yeast at extreme pH. The activity of the tricarboxylic acid cycle enzymes, namely NAD-dependent isocitrate dehydrogenase, aconitate hydratase, NAD-dependent malate dehydrogenase, and fumarate hydratase, NADPH-producing enzymes of glucose-6-P dehydrogenase and NADP-dependent isocitrate dehydrogenase, and the enzymes of the glutathione system was assessed. All the enzymes that were tested showed a significant induction contrary to some decrease in the aconitate hydratase activity with acidic and alkaline stress. It is probable that a change in the enzyme activity in the mitochondria matrix is involved in the regulation of the cellular metabolism of Y. lipolytica, which allows the species to prosper at an extreme ambient pH. It distinguishes it from any other type of ascomycete. A close relationship between the induction of the Krebs cycle enzymes and the key enzymes of the glutathione system accompanied by an increased level of reduced glutathione was shown. The assumption that the increased activity of the Krebs cycle dehydrogenases and promotion of the pentose phosphate pathway at pH stress launches a set of events determining the adaptive response of Y. lipolytica yeast.

Synergistic Dual Targeting of Thioredoxin and Glutathione Systems Irrespective of p53 in Glioblastoma Stem Cells.

Glioblastoma (GBM) is an incurable primary brain cancer characterized by increased reactive oxygen species (ROS) production. The redox-sensitive tumor suppressor gene TP53, wild-type (wt) for 70% of patients, regulates redox homeostasis. Glioblastoma stem cells (GSCs) increase thioredoxin (Trx) and glutathione (GSH) antioxidant systems as survival redox-adaptive mechanisms to maintain ROS below the cytotoxic threshold. Auranofin, an FDA-approved anti-rheumatoid drug, inhibits thioredoxin reductase 1 (TrxR1). L-buthionine sulfoximine (L-BSO) and the natural product piperlongumine (PPL) inhibit the GSH system. We evaluated the cytotoxic effects of Auranofin alone and in combination with L-BSO or PPL in GBM cell lines and GSCs with a known TP53 status. The Cancer Genome Atlas/GBM analysis revealed a significant positive correlation between wtp53 and TrxR1 expression in GBM. Auranofin induced ROS-dependent cytotoxicity within a micromolar range in GSCs. Auranofin decreased TrxR1 expression, AKT (Ser-473) phosphorylation, and increased p53, p21, and PARP-1 apoptotic cleavage in wtp53-GSCs, while mutant-p53 was decreased in a mutant-p53 GSC line. Additionally, p53-knockdown in a wtp53-GSC line decreased TrxR1 expression and significantly increased sensitivity to Auranofin, suggesting the role of wtp53 as a negative redox-sensitive mechanism in response to Auranofin in GSCs. The combination of Auranofin and L-BSO synergistically increased ROS, decreased IC50s, and induced long-term cytotoxicity irrespective of p53 in GBM cell lines and GSCs. Intriguingly, Auranofin increased the expression of glutathione S-transferase pi-1 (GSTP-1), a target of PPL. Combining Auranofin with PPL synergistically decreased IC50s to a nanomolar range in GSCs, supporting the potential to repurpose Auranofin and PPL in GBM.

Impaired Upper Airway Muscle Function with Excessive or Deficient Dietary Intake of Selenium in Rats.

Obstructive sleep apnoea (OSA) involves impaired upper airway muscle function and is linked to several pathologies including systemic hypertension, daytime somnolence and cognitive decline. Selenium is an essential micronutrient that exerts many of its effects through selenoproteins. Evidence indicates that either deficient or excessive dietary selenium intake can result in impaired muscle function, termed nutritional myopathy. To investigate the effects of selenium on an upper airway muscle, the sternohyoid, rats were fed on diets containing deficient, normal (0.5 ppm sodium selenite) or excessive (5 ppm selenite) selenium for a period of two weeks. Sternohyoid contractile function was assessed ex vivo. Serum selenium levels and activity of the glutathione antioxidant system were determined by biochemical assays. The abundance of three key muscle selenoproteins (selenoproteins -N, -S and -W (SELENON, SELENOS and SELENOW)) in sternohyoid muscle were quantified by immunoblotting. Levels of these selenoproteins were also compared between rats exposed to chronic intermittent hypoxia, a model of OSA, and sham treated animals. Although having no detectable effect on selected organ masses and whole-body weight, either selenium-deficient or -excessive diets severely impaired sternohyoid contractile function. These changes did not involve altered fibre size distribution. These dietary interventions resulted in corresponding changes in serum selenium concentrations but did not alter the activity of glutathione-dependent antioxidant systems in sternohyoid muscle. Excess dietary selenium increased the abundance of SELENOW protein in sternohyoid muscles but had no effect on SELENON or SELENOS. In contrast, chronic intermittent hypoxia increased SELENON, decreased SELENOW and had no significant effect on SELENOS in sternohyoid muscle. These findings indicate that two-week exposure to selenium-deficient or -excessive diets drastically impaired upper airway muscle function. In the sternohyoid, SELENON, SELENOS and SELENOW proteins show distinct alterations in level following exposure to different dietary selenium intakes, or to chronic intermittent hypoxia. Understanding how alterations in Se and selenoproteins impact sternohyoid muscle function has the potential to be translated into new therapies for prevention or treatment of OSA.

Diagnostic sensitivity and specificity of indicators of glutathione antioxidant system in spermatozoa of infertile men with different forms of pathospermia

Background. One of the most important antioxidant defence mechanism in spermatozoa is the gluthatione system which includes glutathione peroxidase (GPx), glutathione reductase (GR), glutathione S-transferase (GST) and reduced glutathione (GSH). It is promising to use ROC analysis, which allows to assessing the diagnostic sensitivity and specificity of indicators. Materials and methods. Infertile men were divided into 3 groups: patients with oligozoospermia (n = 30), asthenozoospermia (n = 34), and oligoasthenozoospermia (n = 22). To assess the diagnostic sensitivity and specificity of indicators, the values of the biomarkers were tested using the receiver operating characteristic (ROC) curve, and the area under it (AUC), the standard error (SE) and the 95% confidence interval (CI 95%) were calculated. Results. The ROC analysis showed that GP activity was characterized by excellent diagnostic significance for diagnosing both oligozoospermia and asthenozoospermia (the sensitivity was 100%, and specificity – 100%). The GR activity has moderate diagnostic significance, since the AUC is 0.654 (95% CI from 0.503 to 0.785, P = 0.0645) for oligozoospermic, the AUC is 0.612 (95% CI from 0.454 to 0.7555, P = 0.1979) for asthenozoospermic men. The analysis of the ROC curve revealed a good diagnostic value of GsT activity in sperm samples for the diagnosis of pathospermia (sensitivity of 75% and specificity of 80%). Simultaneously, it was shown that GSH content could not serve as valuable biomarkers for distinguishing patients with pathospermia from healthy controls, with an AUC of 0.615, corresponding to moderate diagnostic significance for oligozoospermia. Conclusion. The results of this study show that the cut-off points for the biomar­kers glutathione peroxidase and glutathione-S-transferase can be used to distinguish between patients with pathospermia and normozoospermia, and the parameters themselves can serve as valuable diagnostic biomarkers to distinguish patients with pathospermia from healthy controls, regardless of the causes of pathospermia. The value of these indicators below the cut-off point indicates the probable presence of pathology. Indicators of GR activity and GSH content have a low diagnostic value, which makes them unsuitable for use as laboratory tests for the diagnosis of male infertility.

Pro-Oxidant Auranofin and Glutathione-Depleting Combination Unveils Synergistic Lethality in Glioblastoma Cells with Aberrant Epidermal Growth Factor Receptor Expression.

Glioblastoma (GBM) is the most prevalent and advanced malignant primary brain tumor in adults. GBM frequently harbors epidermal growth factor receptor (EGFR) wild-type (EGFRwt) gene amplification and/or EGFRvIII activating mutation. EGFR-driven GBM relies on the thioredoxin (Trx) and/or glutathione (GSH) antioxidant systems to withstand the excessive production of reactive oxygen species (ROS). The impact of EGFRwt or EGFRvIII overexpression on the response to a Trx/GSH co-targeting strategy is unknown. In this study, we investigated Trx/GSH co-targeting in the context of EGFR overexpression in GBM. Auranofin is a thioredoxin reductase (TrxR) inhibitor, FDA-approved for rheumatoid arthritis. L-buthionine-sulfoximine (L-BSO) inhibits GSH synthesis by targeting the glutamate-cysteine ligase catalytic (GCLC) enzyme subunit. We analyzed the mechanisms of cytotoxicity of auranofin and the interaction between auranofin and L-BSO in U87MG, U87/EGFRwt, and U87/EGFRvIII GBM isogenic GBM cell lines. ROS-dependent effects were assessed using the antioxidant N-acetylsteine. We show that auranofin decreased TrxR1 activity and increased ROS. Auranofin decreased cell vitality and colony formation and increased protein polyubiquitination through ROS-dependent mechanisms, suggesting the role of ROS in auranofin-induced cytotoxicity in the three cell lines. ROS-dependent PARP-1 cleavage was associated with EGFRvIII downregulation in U87/EGFRvIII cells. Remarkably, the auranofin and L-BSO combination induced the significant depletion of intracellular GSH and synergistic cytotoxicity regardless of EGFR overexpression. Nevertheless, molecular mechanisms associated with cytotoxicity were modulated to a different extent among the three cell lines. U87/EGFRvIII exhibited the most prominent ROS increase, P-AKT(Ser-473), and AKT decrease along with drastic EGFRvIII downregulation. U87/EGFRwt and U87/EGFRvIII displayed lower basal intracellular GSH levels and synergistic ROS-dependent DNA damage compared to U87MG cells. Our study provides evidence for ROS-dependent synergistic cytotoxicity of auranofin and L-BSO combination in GBM in vitro. Unraveling the sensitivity of EGFR-overexpressing cells to auranofin alone, and synergistic auranofin and L-BSO combination, supports the rationale to repurpose this promising pro-oxidant treatment strategy in GBM.

Вплив препаратів метаболічної дії на розвиток окисного стресу у хворих на цукровий діабет 2-го типу

It was shown that the combined oral use of drugs with a metabolic effect - armadine at a dose of 300 mg per day and trizipin at a dose of 500 mg per day for 60 days led to inhibition of the oxidative stress damaging effect on its molecular genetic targets - proteins, lipids, and DNA - in blood of patients with type 2 diabetes mellitus (DM2). This is evidenced by a decrease in the proteins’ oxidative modification level and the content of lipid peroxidation secondary products in blood plasma and changes in the expression of the transcription factor HIF-1α and the regulatory protein mTOR genes in leukocytes of patients with DM2. This occurred against the background of a fall in the hydrogen peroxide production in erythrocytes of patients with DM2 and an increase in the activity of antiradical defense and the glutathione antioxidant system in plasma and erythrocytes of these patients after treatment. Genetic studies indicated that the use of armadine in combination with trizipin significantly raised the expression of the HIF-1α gene and reduced the decrease in the expression of the mTOR gene in blood leukocytes of patients with type 2 diabetes mellitus. The established changes can serve as a protective mechanism that counteracts the development of oxidative damage of macromolecules through various signaling metabolic pathways.

Hypoxia exposure blunts angiogenic signaling and upregulates the antioxidant system in endothelial cells derived from elephant seals

BackgroundElephant seals exhibit extreme hypoxemic tolerance derived from repetitive hypoxia/reoxygenation episodes they experience during diving bouts. Real-time assessment of the molecular changes underlying protection against hypoxic injury in seals remains restricted by their at-sea inaccessibility. Hence, we developed a proliferative arterial endothelial cell culture model from elephant seals and used RNA-seq, functional assays, and confocal microscopy to assess the molecular response to prolonged hypoxia.ResultsSeal and human endothelial cells exposed to 1% O2 for up to 6 h respond differently to acute and prolonged hypoxia. Seal cells decouple stabilization of the hypoxia-sensitive transcriptional regulator HIF-1α from angiogenic signaling. Rapid upregulation of genes involved in glutathione (GSH) metabolism supports the maintenance of GSH pools, and intracellular succinate increases in seal but not human cells. High maximal and spare respiratory capacity in seal cells after hypoxia exposure occurs in concert with increasing mitochondrial branch length and independent from major changes in extracellular acidification rate, suggesting that seal cells recover oxidative metabolism without significant glycolytic dependency after hypoxia exposure.ConclusionsWe found that the glutathione antioxidant system is upregulated in seal endothelial cells during hypoxia, while this system remains static in comparable human cells. Furthermore, we found that in contrast to human cells, hypoxia exposure rapidly activates HIF-1 in seal cells, but this response is decoupled from the canonical angiogenesis pathway. These results highlight the unique mechanisms that confer extraordinary tolerance to limited oxygen availability in a champion diving mammal.

Subgroups of patients with late onset schizophrenia-like psychoses revealed by the analysis of glutathione-dependent enzymes and inflammation markers

IntroductionWhile chronic inflammation and enhanced imbalance of pro- and antioxidant, including glutathione-dependent, systems contribute substantially to pathogenesis of mental disorders in old age, extent of oxidative stress and degree of inflammatory processes severity are varying among patients with late onset schizophrenia.ObjectivesRevealing various phenotypes in patients with late onset schizophrenia basing on measurement of activity levels for blood glutathione-dependent enzymes and inflammation markers and analysis of their links with clinical features of the patients.MethodsOf 59 studied women patients 34 were with late onset (after 40 years) and 25 with very late onset (after 60 years) schizophrenia or schizophrenia-like psychoses (F20; F22.8; F25; F23; F06.2 by ICD-10). 34 mentally healthy women elder than 50 years comprised controls. Glutathione reductase (GR), glutathione-S-transferase (GST), neutrophil elastase (NE), and α1-roteinase inhibitor (α1-PI) activities were measured in blood. PANSS, CDSS and CGI-S were used to assess the severity of psychotic symptoms, depression and treatment effectiveness.ResultsIn the whole group of patients, GR was lower (p<0.05), and α1-PI was higher (p<0.0001) than in control group. Clustering the patients by their biochemical and immunological signs revealed two clusters (C1, n=34, and C2, n=25) significantly differing by GST (p<0.0001), NE (p<0.0001), and α1-PI (p<0.001) activities. As compared with controls, GST and α1-PI were higher (p<0.05 and p<0.0001), and NE was lower (p<0.05) in C1. As compared with controls, GR activity was lower (p<0.05), NE activity was higher (p<0.001), and α1-PI activity was much higher (p<0.001) in C2. Patients of C1 and C2 did not differ in age, diagnosis, severity of the disease, but differed in clinical features of the course of the disease: significantly more patients with very late onset schizophrenia (76%) were met in C1 (χ2=13.41, p<0.001). Also, different clinical-biological correlations were found in these clusters. Particularly, negative correlations of baseline NE activity with PANSS general psychopathology subscale scores (R=-0.39, p<0.05) and with total PANSS scores (R=-0.39, p<0.05) were found in C1. Positive correlation of GST activity with PANSS positive subscale score was found in C2 (R=0.43, p<0.05).ConclusionsThe revealed clusters differ in the extent of the glutathione antioxidant system impairment and in levels of the immune response markers. The revealing of the patient subgroups on the basis of biological markers reflecting impairments in metabolic and immune systems can represent interest in the search for individual treatment approaches.Disclosure of InterestNone Declared

Understanding fenpropathrin-induced pulmonary toxicity: What apoptosis, inflammation, and pyreptosis reveal analyzing cross-links at the molecular, immunohistochemical, and immunofluorescent levels

Fenpropathrin (FN), a pyrethroid has been linked to potential pulmonary toxic effects to humans via incident direct or indirect ingestion. Thus, we aimed to the investigate the underlying mechanisms of lung toxicity upon exposure to FN in the rat model, besides studying whether curcumin (CCM) and curcumin-loaded chitosan nanoformulation (CCM-Chs) can mitigate FN-induced lung damage. Six distinct groups, namely, control, CCM, CCM-Chs, FN, and CCM + FN, CCM-Chs + FN were assigned separately. The inflammatory, apoptotic, and oxidative stress states, histological, immunohistochemical, and immunofluorescence examination of different markers within the pulmonary tissue were applied. The results revealed that the FN-induced tissue damage might be caused by the oxidative stress induction and depressed antioxidant glutathione system in the lungs of rats. Furthermore, FN upregulated the expression of genes related to inflammation, and pyroptosis, and elevated the immunoreactivity of Caspase-3, tumor necrosis factor-α, vimentin, and 4-Hydroxynonenal in pulmonary tissues of FN-exposed rats compared to the control. CCM and CCM-Chs mitigated the FN-induced disturbances, while remarkably, CCM-Chs showed better potency than CCM in mitigating the FN-induced toxicity. In conclusion, this study shows the prominent preventive ability of CCM-Chs more than CCM in combatting the pulmonary toxicity induced by FN. This may be beneficial in developing therapeutic and preventive strategies against FN-induced pulmonary toxicity.

Marine Polysaccharides Carrageenans Enhance Eryptosis and Alter Lipid Order of Cell Membranes in Erythrocytes.

Carrageenans of ι-, κ- and λ-types were incubated with washed erythrocytes (hematocrit 0.4%) at 0-1-5-10 g/L for either 24 h or 48 h. Incubation was followed by flow cytometry-based quantitative analysis of eryptosis parameters, including cell volume, cell membrane scrambling and reactive oxygen species (ROS) production, lipid peroxidation markers and confocal microscopy-based evaluation of intracellular Ca2+ levels, assessment of lipid order in cell membranes and the glutathione antioxidant system. Confocal microscopy was used to assess carrageenan cellular internalization using rhodamine B isothiocyanate-conjugated carrageenans. All three types of carrageenans were found to trigger eryptosis. Pro-eryptotic properties were type-dependent and λ-carrageenan had the strongest impact inducing phosphatidylserine membrane asymmetry, changes in cell volume, Ca2+ signaling and oxidative stress characterized by ROS overproduction, activation of lipid peroxidation and severe glutathione system depletion. Eryptosis induction by carrageenans does not require their uptake by erythrocytes. Changes in physicochemical properties of cell membrane were also type-dependent. No carrageenan-induced generation of superoxide and hydroxyl radicals was observed in cell-free milieu. Our findings suggest that ι-, κ- and λ-types trigger eryptosis in a type-dependent manner and indicate that carrageenans can be further investigated as potential eryptosis-regulating therapeutic agents.

Carnosol ameliorated cancer cachexia-associated myotube atrophy by targeting P5CS and its downstream pathways.

Introduction: Carnosol exhibited ameliorating effects on muscle atrophy of mice developed cancer cachexia in our previous research. Method: Here, the ameliorating effects of carnosol on the C2C12 myotube atrophy result from simulated cancer cachexia injury, the conditioned medium of the C26 tumor cells or the LLC tumor cells, were observed. To clarify the mechanisms of carnosol, the possible direct target proteins of carnosol were searched using DARTS (drug affinity responsive target stability) assay and then confirmed using CETSA (cellular thermal shift assay). Furthermore, proteomic analysis was used to search its possible indirect target proteins by comparing the protein expression profiles of C2C12 myotubes under treatment of C26 medium, with or without the presence of carnosol. The signal network between the direct and indirect target proteins of carnosol was then constructed. Results: Our results showed that, Delta-1-pyrroline-5-carboxylate synthase (P5CS) might be the direct target protein of carnosol in myotubes. The influence of carnosol on amino acid metabolism downstream of P5CS was confirmed. Carnosol could upregulate the expression of proteins related to glutathione metabolism, anti-oxidant system, and heat shock response. Knockdown of P5CS could also ameliorate myotube atrophy and further enhance the ameliorating effects of carnosol. Discussion: These results suggested that carnosol might ameliorate cancer cachexia-associated myotube atrophy by targeting P5CS and its downstream pathways.

Dynamics of the content of reactive oxygen species and the state of the glutathione system in the oral cavity during subchronic intoxication wuth the fungicide thiram and its antioxidant correction.

Thiram is a dithiocarbamate derivative, which is used as a fungicide for seed dressing and spraying during the vegetation period of plants, and also as an active vulcanization accelerator in the production of rubber-based rubber products. In this study the content of reactive oxygen species (ROS) and the state of the glutathione system have been investigated in the oral fluid and gum tissues of adult male Wistar rats treated with thiram for 28 days during its administration with food at a dose of 1/50 LD50. Thiram induced formation of ROS in the oral cavity; this was accompanied by an imbalance in the ratio of reduced and oxidized forms of glutathione due to a decrease in glutathione and an increase in its oxidized form as compared to the control. Thiram administration caused an increase in the activity of glutathione-dependent enzymes (glutathione peroxidase, glutathione transferase, and glutathione reductase). However, the time-course of enzyme activation in the gum tissues and oral fluid varied in dependence on the time of exposure to thiram. In the oral fluid of thiram-treated rats changes in the antioxidant glutathione system appeared earlier. The standard diet did not allow the glutathione pool to be fully restored to physiological levels after cessation of thiram intake. The use of exogenous antioxidants resviratrol and an Echinacea purpurea extract led to the restoration of redox homeostasis in the oral cavity.

Lactic acid fermentation of goji berries (Lycium barbarum) prevents acute alcohol liver injury and modulates gut microbiota and metabolites in mice.

Juice fermented with lactic acid bacteria (LAB) has received attention due to its health benefits, such as antioxidant and anti-inflammatory. Previous research on LAB-fermented goji juice mainly focused on exploring the changes in the metabolite profile and antioxidant activity in vitro, whereas the liver protection properties of LAB-fermented goji juice in vivo are still unknown. This study aimed to investigate the effects of Lacticaseibacillus paracasei E10-fermented goji juice (E10F), Lactiplantibacillus plantarum M-fermented goji juice (MF), Lacticaseibacillus rhamnosus LGG-fermented goji juice (LGGF) on preventing acute alcoholic liver injury with physiology, gut microbial, and metabolic profiles in mice. Compared with goji juice, E10F, MF, and LGGF enhanced the protective effect against liver injury by reducing serum alanine transaminase (ALT) levels, improving the hepatic glutathione (GSH) antioxidant system, and attenuating inflammation by decreasing the levels of interleukin (IL)-1β, IL-6, tumor necrosis factor (TNF)-α, and transforming growth factor (TGF)-β. Furthermore, E10F, MF, and LGGF increased intestinal integrity, restructured the gut microbiota including Bacteroides and Lactobacillus, and altered gut microbial metabolites including kyotorphin, indolelactic acid, and N-methylserotonin. Pretreatment of different LAB-fermented goji juice in mice showed significant differences in gut microbiota and metabolism. The correlation analysis demonstrated that the increase of Lactobacillus, indolelactic acid, and N-methylserotonin by E10F, MF, and LGGF was positively correlated with reduced inflammation and improved liver and gut function. Taken together, E10F, MF, and LGGF all have the potential to be converted into dietary interventions to combat acute alcoholic liver injury. It provided a reference for the study of the hepatoprotective effect of LAB-fermented goji juice.

Prevalence of Glucose-6-Phosphate Dehydrogenase deficiency among Hausa and Fulani ethnics in Kano, North-West Nigeria

Background: Glucose-6-phosphate dehydrogenase catalyzes the rate-determining step in the pentose phosphate pathway. Its activity is a key determinant of the reduced nicotinamide adenine dinucleotide phosphate to oxidized nicotinamide adenine dinucleotide phosphate (NADPH-to-NADP+) ratio in the cytoplasm and thus contributes to the replenishment of the antioxidant glutathione system. Glucose-6-phosphate dehydrogenase deficiency is a common X-linked human enzyme defect of red blood cells. Individuals with this gene defect appear normal until exposed to oxidative stress which induces haemolysis but it is infrequently taken into consideration in health practices. Aim: The present work was designed to determine the frequency of occurrence of glucose-6-phosphate dehydrogenase (G-6-PD) deficiency among Hausa and Fulani ethnics. Material and methods: Cross-sectional comparative study in which 5 mL of venous blood samples were collected from 1000 individuals (596 males and 404 females) all of whom gave informed consent were screened for G-6-PD-deficiency by qualitative methaemoglobin reduction and quantitative enzyme activity measurement techniques. Results: Glucose-6-phoshate dehydrogenase deficiency was found in 194 (19.4%) of participants studied. Of these 10.3% were Fulani and 22.2% were Hausa with mean G-6-PD enzyme activity of 2.5 IU/gHb in a range from 1.4 to 2.4 IU/gHb. G-6-PD deficiency was found in 121 of 596 (20.3%) males and 73 of 404 (18.1%) females screened. Conclusions: These results suggest high occurrence of phenotypic G-6-PD deficiency in Hausa ethnics of Kano with lower enzyme status among males living with G-6-PD deficiency.

Effects of Dietary Zinc Deficiency and Supplementation on Prepubertal Rat Testes: Sulfhydryl and Antioxidant Status.

The study was designed to investigate the effects of dietary zinc deficiency and supplementation on antioxidant system viz. superoxide-dismutase, glutathione reductase, glutathione peroxidase, glutathione- S-transferase, catalase and sulfhydryls levels (GSH, TSH, NPSH and PBSH) in testes of Wistar rats. Pre-pubertal rats were divided into two groups with 6 sub-groups each viz. zinc control (ZC), pair fed (PF), zinc deficient (ZD), zinc control supplementation (ZCS), pair-fed supplementation (PFS) and zinc deficient supplementation (ZDS). Experiments were set for 2- and 4-weeks followed by 4weeks of zinc supplementation. The zinc deficient group animals exhibited significant decrease in gonado-somatic index (2- and 4- weeks), sulfhydryls levels, GSH, GPx, GR (2 and 4-weeks) and GST concentration (2-weeks). However, after zinc supplementation significant improvement in gonadosomatic index, SH, GSH, antioxidant enzyme levels (GR, GPx, and GST) in deficient groups has been observed. Zinc deficiency during pre-pubertal period affected growth and caused dysregulation of the glutathione antioxidant system. The significant alterations in the levels of antioxidant enzymes and non-enzymatic antioxidant system (GSH and SH) in zinc deficient groups could be due to alleviated generation of free radicals, causative factor for increased oxidative stress which may lead to infertility as oxidative stress is a common pathology seen during infertility. Altered antioxidant system and sulfhydryls levels in testes due to dietary zinc deficiency reflect the significance of optimum zinc for maintaining homeostatic balance in gonadal physiology. Supplementing zinc for 4weeks could reduce the redox imbalance which may help in alleviating oxidative stress induced alterations in testes.

Mitochondrial aldehyde dehydrogenase-2 coordinates the hydrogen sulfide - AMPK axis to attenuate high glucose-induced pancreatic β-cell dysfunction by glutathione antioxidant system

Progression of β-cell loss in diabetes mellitus is significantly influenced by persistent hyperglycemia. At the cellular level, a number of signaling cascades affect the expression of apoptotic genes, ultimately resulting in β-cell failure; these cascades have not been elucidated. Mitochondrial aldehyde dehydrogenase-2 (ALDH2) plays a central role in the detoxification of reactive aldehydes generated from endogenous and exogenous sources and protects against mitochondrial deterioration in cells. Here we report that under diabetogenic conditions, ALDH2 is strongly inactivated in β-cells through CDK5-dependent glutathione antioxidant imbalance by glucose-6-phosphate dehydrogenase (G6PD) degradation. Intriguingly, CDK5 inhibition strengthens mitochondrial antioxidant defense through ALDH2 activation. Mitochondrial ALDH2 activation selectively preserves β-cells against high-glucose-induced dysfunction by activating AMPK and Hydrogen Sulfide (H2S) signaling. This is associated with the stabilization and enhancement of the activity of G6PD by SIRT2, a cytoplasmic NAD+-dependent deacetylase, and is thereby linked to an elevation in the GSH/GSSG ratio, which leads to the inhibition of mitochondrial dysfunction under high-glucose conditions. Furthermore, treatment with NaHS, an H2S donor, selectively preserves β-cell function by promoting ALDH2 activity, leading to the inhibition of lipid peroxidation by high-glucose concentrations. Collectively, our results provide the first direct evidence that ALDH2 activation enhances H2S-AMPK-G6PD signaling, leading to improved β-cell function and survival under high-glucose conditions via the glutathione redox balance.

Dynamic Interplay of Metabolic and Transcriptional Responses in Shrimp during Early and Late Infection Stages of Enterocytozoon hepatopenaei (EHP)

Enterocytozoon hepatopenaei (EHP) is a microsporidian parasite that infects Litopenaeus vannamei, causing severe hepatopancreatic microsporidiosis (HPM) and resulting in significant economic losses. This study utilizes a combined analysis of transcriptomics and metabolomics to unveil the dynamic molecular interactions between EHP and its host, the Pacific white shrimp, during the early and late stages of infection. The results indicate distinct immunological, detoxification, and antioxidant responses in the early and late infection phases. During early EHP infection in shrimp, immune activation coincides with suppression of genes like Ftz-F1 and SEPs, potentially aiding parasitic evasion. In contrast, late infection shows a refined immune response with phagocytosis-enhancing down-regulation of Ftz-F1 and a resurgence in SEP expression. This phase is characterized by an up-regulated detoxification and antioxidant response, likely a defense against the accumulated effects of EHP, facilitating a stable host–pathogen relationship. In the later stages of infection, most immune responses return to baseline levels, while some immune genes remain active. The glutathione antioxidant system is suppressed early on but becomes activated in the later stages. This phenomenon could facilitate the early invasion of EHP while assisting the host in mitigating oxidative damage caused by late-stage infection. Notably, there are distinctive events in polyamine metabolism. Sustained up-regulation of spermidine synthase and concurrent reduction in spermine levels suggest a potential role of polyamines in EHP development. Throughout the infection process, significant differences in genes such as ATP synthase and hexokinase highlight the continuous influence on energy metabolism pathways. Additionally, growth-related pathways involving amino acids such as tryptophan, histidine, and taurine are disrupted early on, potentially contributing to the growth inhibition observed during the initial stages of infection. In summary, these findings elucidate the dynamic interplay between the host, Litopenaeus vannamei, and the parasite, EHP, during infection. Specific phase differences in immune responses, energy metabolism, and antioxidant processes underscore the intricate relationship between the host and the parasite. The disruption of polyamine metabolism offers a novel perspective in understanding the proliferation mechanisms of EHP. These discoveries significantly advance our comprehension of the pathogenic mechanisms of EHP and its interactions with the host.

STEM-09. EXPLORING THE ROLE OF TP53 IN REDOX REGULATION AND RESPONSE OF GLIOBLASTOMA STEM CELLS TO ROS-INDUCING AGENTS

Abstract Glioblastoma, the most malignant primary tumor of the central nervous system in adults presents a major therapeutic challenge due to the presence of chemo-radioresistant glioblastoma stem cells (GSCs). These GSCs adapt the thioredoxin (Trx) and glutathione (GSH) antioxidant systems to counteract treatment-induced reactive oxygen species (ROS) and promote their survival. The tumor suppressor gene wild-type (wt)TP53 regulates the expression of pro-oxidant or antioxidant genes in response to chemoradiotherapy based on p53 DNA-binding activity in a reducing microenvironment. Given the importance of p53 as a redox-sensitive protein, we hypothesized that p53 might protect GSCs against ROS-inducing agents. Auranofin (Au), a FDA-approved gold(I)-containing compound inhibits thioredoxin reductase 1 (TrxR1), a key antioxidant protein. We investigated the effects of Au on different GSCs including wtp53 GSC line and its counterpart p53-knockdown. We assessed viability, neurosphere formation, ROS levels and expression of p53 and TrXR1 to evaluate the cytotoxicity of Au, alone and in combination with L-buthionine sulfoximine (L-BSO), a GSH-depleting agent. We conducted TCGA analysis to explore the correlation between TrxR1 and p53. Our findings revealed a positive significant correlation between p53 and TrxR1 expression, consistent with lower levels of TrxR1 in p53-knockdown GSCs compared to their wt-p53 counterparts. P53-knockdown GSCs displayed a higher basal level of ROS, which further increased upon treatment with Au. P53-knockdown significantly increased the sensitivity of cells to Au, with pronounced effects for Au/L-BSO combination. Our findings reveal that expression levels of wtp53 affect the role of p53 in TrxR1-redox regulation and sensitivity to ROS-inducing agents in GSCs.

The Relationship between Treatment Response in Patients with Acute Psychotic Episodes of Schizophrenia and the Activity of Their Platelet Enzymes

Background: imbalance in the energy processes, such as oxidative phosphorylation intensity, and antioxidant systems, and impaired glutamate metabolism in the brain are important biochemical pathogenetic links in the development of schizophrenia. Changes in the activity of a number of platelet enzymes involved in these biochemical pathways were found in patients with schizophrenia.Aim: to assess the relationship between the treatment effciency of acute psychotic episode in patients with paranoid schizophrenia and the activity levels of platelet enzymes involved in energy metabolism (cytochrome c-oxidase, COX), in the antioxidant glutathione system (glutathione reductase, GR), and glutamate metabolism (glutamate dehydrogenase, GDH).Patients and methods: we examined hospitalized adult patients with a diagnosis of paranoid schizophrenia, episodic course, exacerbation of the disease (F20.01), receiving antipsychotic therapy, and healthy volunteers as a control group for assessment of control ranges for enzymatic activities. Psychometric assessment was carried out using the Positive and Negative Syndrome Scale (PANSS). Treatment response was assessed as good with a reduction in PANSS scores of 20% or more. The evaluation was performed on the first days after hospitalization and immediately before discharge.Results: 113 subjects were recruited. 50 healthy volunteers formed the control group and 63 patients, including 60 men and 3 women made up the study group. All indicators were obtained in all control group members and in 42 patients. In the group with a good treatment response, the baseline COX, GDH and GR activities proved to be significantly more often met within the control range, and the GR activity in half of the patients increased after the treatment course. In the group with insuffcient response, half of the patients had an increase in GDH activity after treatment. Of all the biochemical indices, the parameter most associated with therapeutic response was GDH activity.Conclusion: GDH activity can be considered as a possible candidate for predicting the therapeutic response to antipsychotic therapy.