GSH Peroxidase Research Articles

Advanced Age and Neurotrauma Diminish Glutathione and Impair Antioxidant Defense after Spinal Cord Injury.

Advanced age at the time of spinal cord injury (SCI) exacerbates damage from reactive oxygen species (ROS). Mechanisms underlying this age-dependent response are not well understood and may arise from decreased antioxidant defense. We investigated how spinal cord levels of the antioxidant glutathione (GSH), and its regulation, change with age and SCI. GSH is used by GSH peroxidase to sequester ROS and is recycled by GSH reductase. Male and female, 4- and 14-month-old (MO) mice received a 60 kDyn contusion SCI, and the levels of GSH and its regulatory enzymes were evaluated at one and three days post-injury (dpi). The mice with SCI were treated with N-acetylcysteine-amide (NACA; 150 mg/kg), a cysteine supplement that increases GSH, to determine effects on functional and histological outcomes. GSH was decreased with older age in sham mice, and an SCI-dependent depletion was observed in 4-MO mice by three dpi. Neither age nor injury affected the abundance of proteins regulating GSH synthesis or recycling. GSH peroxidase activity, however, increased after SCI only in 4-MO mice. In contrast, GSH peroxidase activity was increased in 14-MO sham mice, indicating that spinal cords of older mice have an elevated oxidative state. Indeed, 14-MO sham mice had more oxidized protein (3-nitrotyrosine [3-NT]) within their spinal cords compared with 4-MO sham mice. Only 4-MO mice had significant injury-induced increases in 3-NT at three dpi. NACA treatment restored GSH and improved the redox environment in injured 4- and 14-MO mice at one dpi; however, three days of NACA delivery did not improve motor, sensory, or anatomical deficits at 28 dpi in 4-MO mice and trended toward toxicity in all outcomes in 14-MO mice. Our observation suggests that GSH levels at acute stages of SCI play a minimal role in age-dependent outcomes reported after SCI in mice. Collective results implicate elements of injury occurring after three dpi, such as inflammation, as key regulators of age-dependent effects.

Ginsenoside Rg1 ameliorates sepsis-induced acute kidney injury by inhibiting ferroptosis in renal tubular epithelial cells.

Acute kidney injury (AKI) represents a prevailing complication of sepsis, and its onset involves ferroptosis. Ginsenoside Rg1 exerts a positive effect on kidney diseases. This study explored the action of ginsenoside Rg1 in sepsis-induced AKI (SI-AKI) by regulating ferroptosis in renal tubular epithelial cells (TECs). Sepsis rat models were established using cecal ligation and puncture (CLP) and cell models were established by treating human renal TECs (HK-2) with LPS to induce ferroptosis. Serum creatinine (SCr) and blood urea nitrogen (BUN) and urine KIM1 contents in rats were determined by ELISA kits. Kidney tissues were subjected to immunohistochemical and H&E stainings. Iron concentration, malondialdehyde (MDA), glutathione (GSH), and ferroptosis-related protein (ferritin light chain [FTL], ferritin heavy chain [FTH], GSH peroxidase 4 [GPX4], and Ferroptosis suppressor protein 1 [FSP1]) levels in kidney tissues and HK-2 cells were measured using ELISA kits and Western blotting. HK-2 cell viability was detected by cell counting kit-8, and cell death was observed via propidium iodide staining. Reactive oxygen species accumulation in cells was detected using C11 BODIPY 581/591 as a molecular probe. In CLP rats, ginsenoside Rg1 reduced SCr, BUN, KIM1, and NGAL levels, thus palliating SI-AKI. Additionally, ginsenoside Rg1 decreased iron content, FTL, FTH, and MDA levels, and elevated GPX4, FSP1, and GSH levels, thereby inhibiting lipid peroxidation and ferroptosis. Moreover, FSP1 knockdown annulled the inhibition of ginsenoside Rg1 on ferroptosis. In vitro experiments, ginsenoside Rg1 raised HK-2 cell viability and lowered iron accumulation and lipid peroxidation during ferroptosis, and its antiferroptosis activity was dependent on FSP1. Ginsenoside Rg1 alleviates SI-AKI, possibly resulting from inhibition of ferroptosis in renal TECs through FSP1.

Effects of sweet potato vine silage supplementation on meat quality, antioxidant capacity and immune function in finishing pigs.

Sweet potato vine, the byproduct of sweet potato, has a highnutritional value. Silage is an effective solution for nutrientpreservation. This article explored the effects of sweet potato vine silage (SPVS) supplementation on meat quality, antioxidant capacity and immune function in finishing pigs. One hundred and eightyfinishing pigs (Berkshire × Licha Black) with a body weight of 74.54 ± 3.32 kg were randomly divided into three groups. The three groups were separately fed basal diet (Ctrl), Ctrl supplemented with 2.5% SPVS (LSPVS) or 5% SPVS (HSPVS) on a dry matter basis. Results showed that the eye muscle area in the LSPVS group was significantly increased. The carcass weight in the HSPVS was significantly reduced compared with Ctrl. For the meat quality, only cooking loss in both HSPVS and LSPVS was reduced while other indexes had no significant differences. For the antioxidant capacity, the hepatic level of glutathione (GSH) peroxidase (GSH-PX) was significantly upregulated in LSPVS but downregulated in HSPVS. In the serum, HSPVS decreased GSHlevel and increased GSH-PX level. HSPVS significantly reduced hepatic interleukin-1β (IL-1β) levels and LSPVS significantly reduced IL-12levels and increased IL-8and IL-6levels. Moreover, HSPVS and LSPVS promoted the secretion of immunoglobulin M (IgM) and IgGin the serum. Our data showed that low-dose SPVS supplementation improved carcass traits and high-dose SPVS supplementation increased immune function in finishing pigs, which provides a new alternative to improve animal health.

A Comprehensive Comparison of Different Selenium Supplements: Mitigation of Heat Stress and Exercise Fatigue-Induced Liver Injury.

This study aimed to compare the protective effects of different selenium supplements against heat stress and exercise fatigue-induced liver injury and to investigate the potential mechanisms of action. Selenium-enriched soybean protein (SePro), selenium-enriched soybean peptides (SePPs), and selenomethionine (SeMet) are organic selenium supplements in which selenium replaces the sulfur in their sulfur-containing amino acids. Common peptides (PPs) are obtained by enzymatic hydrolysis of soybean protein which was extracted from common soybean. The SePPs with higher hydrolysis degree and selenium retention were isolated via alkaline solubilization and acid precipitation and the enzymatic hydrolysis of alkaline protease, neutral protease, and papain. The results showed that SePPs could significantly increase the antioxidant levels in rats, inhibit lipid peroxidation, and reduce liver enzyme levels in rat serum, while the histological findings indicated that the inflammatory cell infiltration in the liver tissue was reduced, and new cells appeared after treatment with SePPs. Moreover, SePPs could increase glutathione (GSH) and GSH peroxidase (GSH-Px) in the liver, as well as protect the liver by regulating the NF-κB/IκB pathway, prevent interleukin 1β (IL-1β), interleukin 6 (IL-6), and tumor necrosis factor α (TNF-α) release in the liver. The SePPs displayed higher antioxidant and anti-inflammatory activity in vivo than SePro, SeMet, Sodium selenite (Na2SeO3), and PPs. Therefore, SePPs could be used as a priority selenium resource to develop heatstroke prevention products or nutritional supplements.

Deficiency in glutathione synthesis and reduction contributes to the pathogenesis of colitis-related liver injury.

Liver disease is the most common extra-intestinal manifestation of ulcerative colitis (UC), but the underlying pathogenesis is still not clarified. It is well accepted that the occurrence of UC-related liver disease has close correlation with immune activation, intestinal bacterial liver translocation, inflammatory cytokine storm, and the disturbance of bile acid circulation. The occurrence of UC-related liver disease makes the therapy difficult, therefor study on the pathogenesis of UC-related liver injury is of great significance for its prevention and treatment. Glutathione (GSH) shows multiple physiological activities, such as free radical scavenging, detoxification metabolism and immune defense. The synthesis and the oxidation-reduction all contribute to GSH antioxidant function. It is reported that the deficiency in hepatic GSH antioxidant function participates in multiple liver diseases, but whether it participates in the pathogenesis of UC-related liver injury is still not clear. This study aims to investigate the feature and underlying mechanism of GSH synthesis and oxidation-reduction function during the development of UC, which will provide useful information for the pathogenesis study on UC-related liver injury. UC model was induced by 2,4,6-trinitrobenzenesulfonic acid (TNBS)-ethanol solution (5 mg/0.8 mL per rat, 50% ethanol) via intra-colonic administration in rats, and the samples of serum, liver, and colon tissue of rats were collected at the 3rd, 5th, and 7th days post TNBS. The severity degree of colitis was evaluated by measuring the disease activity index, colonic myeloperoxidase activity, and histopathological score, and the degree of liver injury was evaluated by histopathological score and the serum content of alanine aminotransferase. Spearman correlation analysis was also conducted between the degree of colonic lesions and index of hepatic histopathological score as well as serum aspartate aminotransferase level to clarify the correlation between liver injury and colitis. To evaluate the hepatic antioxidant function of GSH in UC rats, hepatic GSH content, enzyme activity of GSH peroxidase (GSH-Px), and GSH reductase (GR) were determined in rats at the 3rd, 5th, and 7th days post TNBS, and the protein expressions of glutamine cysteine ligase (GCL), GSH synthase, GSH-Px, and GR in the liver of UC rats were also examined by Western blotting. Compared with the control, the disease activity index, colonic myeloperoxidase activity, and histopathological score were all significantly increased at the 3rd, 5th, and 7th days post TNBS (all P<0.01), the serum aspartate aminotransferase level and hepatic histopathologic score were also obviously elevated at the 7th day post TNBS (all P<0.05). There was a significant positive correlation between the degree of liver injury and the severity of colonic lesions (P=0.000 1). Moreover, compared with the control, hepatic GSH content and the activity of GSH-Px and GR were all significantly decreased at the 3rd and 5th days post TNBS (P<0.05 or P<0.01), and the protein expressions of GCL, GSH-Px, and GR were all obviously down-regulated at the 3rd, 5th, and 7th days post TNBS (P<0.05 or P<0.01). There is a significant positive correlation between the degree of liver injury and the severity of colonic lesions, and the occurrence of reduced hepatic GSH synthesis and decreased GSH reduction function is obviously earlier than that of the liver injury in UC rats. The reduced hepatic expression of enzymes that responsible for GSH synthesis and reduction may contribute to the deficiency of GSH synthesis and oxidation-reduction function, indicating that the deficiency in GSH antioxidant function may participate in the pathogenesis of UC related liver injury.

Network Pharmacology Identifies Therapeutic Targets and the Mechanisms of Glutathione Action in Ferroptosis Occurring in Oral Cancer.

Oral cancer (OC) is one of the most pernicious cancers with increasing incidence and mortality worldwide. Surgery is the primary approach for the treatment of early-stage OC, which reduces the quality of life of the patients. Therefore, there is an urgent need to discover novel treatments for OC. Targeting ferroptosis to induce cell death through the modulation of lipid oxidation has been used as a new approach to treat many cancers. Glutathione (GSH) is a coenzyme factor of GSH peroxidase 4, and it carries potential applicability in treating OC. By using network pharmacology and molecular docking followed by systematic bioinformatic analysis, we aimed to study GSH-targeting ferroptosis to treat OC. We identified 14 core molecular targets, namely, EGFR, PTGS2, HIF1A, VEGFA, TFRC, SLC2A1, CAV1, CDKN2A, SLC3A2, IFNG, NOX4, DDIT4, CA9, and DUSP1, involved in ferroptosis that were targeted by GSH for OC treatment. Functional characterization of these molecular targets showed their importance in the control of cell apoptosis, cell proliferation, and immune responses through various kinase activities such as the mitogen-activated protein kinase activity (e.g., ERK1 and ERK2 cascades) and modulation of TOR signaling (e.g., the HIF-1 signaling pathway). Molecular docking further revealed the direct binding of GSH with EGFR, PTGS2, and HIF1A proteins. These findings provide a novel insight into the targets of GSH in ferroptosis as well as possible molecular mechanisms involved, suggesting the possible use of GSH as a combined therapy for treating OC.

Effects of dietary thyme essential oil on blood haematobiochemical, redox status, immunological and reproductive variables of rabbit does exposed to high environmental temperature

Dietary manipulations play an important role in improving the rabbit behaviour and performance and mitigating the negative effects of heat stress (HS) in rabbits. Thus, this study was designed to determine the modulatory role of thyme essential oil (TEO) in improving the blood metabolites, antioxidant status, immunological response, ovarian activity, reproductive traits and fecundity of rabbit does kept under high environmental stress. A total of 100 nulliparous does were used and randomly assigned into five treatments of 20 does each. The basal diet fed to the experimental groups contained TEO at levels of 0, 50, 100, 150 and 200 mg/kg diet for the 1st, 2nd, 3rd, 4th and 5th groups, respectively. The period of TEO treatment was one month during an experimental period of three months during the summer season. Results showed that TEO at a level of 100 mg/kg diet decreased (p ≤ .001) MDA, while increased (≤.001) total proteins (TPs), albumin (AL), globulin (GL), blood haemoglobin, total antioxidant capacity (TAC), haematocrit (Ht) and glutathione (GSH). Conversely, the TEO treatment did not affect GSH peroxidase and superoxide dismutase (SOD). Immunological variables (IgG and IgM), milk production, ovulation rate (OR) and normal embryos percentage were significantly improved by 100 mg TEO/kg diet supplementation. The reproductive variable of stressed rabbit does fed TEO were significantly higher than those in the control diet. Collectively, dietary TEO supplementation can alleviate the negative influences of heat stressed-female rabbits, via enhancing the antioxidant capacity and immunological parameters. Highlights Dietary manipulations play an important role in improving the rabbit behaviour and performance. Addition of TEO to rabbit diets improved rabbit performance and health as well as reduced the negative effects of heat stress (HS). Immunological indices and milk production, ovulation rates (ORs) and normal embryos were significantly improved by TEO. Thyme essential oil (TEO) decreased MDA and increased protein and its fraction, blood haemoglobin and total antioxidant capacity (TAC).

Glutamine Supplementation Attenuates Bisphenol A-Induced Testicular Toxicity in Rats.

The induction of testicular toxicity by bisphenol A (BPA) may involve oxidative stress. Glutamine (Gln) is a rate limiter for the synthesis of glutathione (GSH), which inhibits oxidative stress. This study assessed the potential of BPA to preserve testicular structure and function in BPA-treated albino rats. Thirty-two adult male albino rats (210-250 g) were randomly allocated to 4 (A-D) of 8 rats per group with the approval of the Research Ethics Committee. Groups B-D were orally treated with Gln (20 mg/kg body weight), BPA (50 mg/kg body weight) and Gln (20 mg/kg body weight) + BPA (50 mg/kg body weight) daily for 65 days, respectively. Group A (control) was orally treated with normal saline (0.2 mL) daily for 65 days. At the termination of treatment, the rats were weighed and anaesthetized blood samples were collected and evaluated for gonadal hormones. The testes were weighed and evaluated for sperm parameters, oxidative stress markers and histology. The data were analysed using one-way analysis of variance and Bonferroni post hoc test. BPA caused a significant (P < 0.001) decrease in testis and body weights, sperm count, volume, motility and normal morphology when compared to the control. BPA significantly (P < 0.001) decreased serum testosterone, follicle-stimulating hormone, luteinising hormone, testicular catalase, superoxide dismutase, GSH and GSH peroxidase levels relative to control. Significantly (P < 0.001) increased serum prolactin, estradiol and testicular malondialdehyde levels occurred in BPA-treated rats relative to control. The testes of BPA-treated rats showed sloughing and coalescence of germ cells. However, Gln supplementation prevents BPA-induced testicular toxicity. Gln supplementation restored testis histology. Based on the observation in this study, Gln seems effective against BPA-induced testicular toxicity.

Radiation affects glutathione redox reaction by reduced glutathione peroxidase activity in human fibroblasts.

The glutathione (GSH) redox control is critical to maintain redox balance in the body’s internal environment, and its perturbation leads to a dramatic increase in reactive oxygen species (ROS) levels and oxidative stress which have negative impacts on human health. Although ionizing radiation increases mitochondrial ROS generation, the mechanisms underlying radiation-induced late ROS accumulation are not fully understood. Here we investigated the radiation effect on GSH redox reactions in normal human diploid lung fibroblasts TIG-3 and MRC-5. Superoxide anion probe MitoSOX-red staining and measurement of GSH peroxidase (GPx) activity revealed that high dose single-radiation (SR) exposure (10 Gy) increased mitochondrial ROS generation and overall oxidative stress in parallel with decrease in GSH peroxidase (GPx) activity, while GSH redox control was effective after exposure to moderate doses under standard serum conditions. We used different serum conditions to elucidate the role of serum on GSH redox reaction. Serum starvation, serum deprivation and DNA damage response (DDR) inhibitors-treatment reduced the GPx activity and increased mitochondrial ROS generation regardless of radiation exposure. Fractionated-radiation was used to evaluate the radiation effect on GSH reactions. Repeated fractionated-radiation induced prolonged oxidative stress by down-regulation of GPx activity. In conclusion, radiation affects GSH usage according to radiation dose, irradiation methods and serum concentration. Radiation affected the GPx activity to disrupt fibroblast redox homeostasis.

MR imaging guided iron-based nanoenzyme for synergistic Ferroptosis−Starvation therapy in triple negative breast cancer

Triple negative breast cancer (TNBC), as the most aggressive BC, accounts for the leading cause of worldwide women death. Owing to the deficiency of related hormone receptors, the efficacy of hormone therapy on TNBC is significantly confined in clinical treatment. Ferroptosis, a newly emerging antitumor strategy through enhancing iron-dependent lipid peroxides level to induce cancer cell death without the mediation of cell receptors, has been proved to be feasible in various cancer treatments. However, the high glutathione (GSH) level in tumor microenvironment limits the anti-tumor efficacy of ferroptosis. Herein, superparamagnetic iron oxide (SPIO) based nanoenzyme modified with Avastin (Ava) was designed and successfully prepared for synergistic ferroptosis and starvation therapy of TNBC. Through downregulating the GSH and glutathione peroxidase 4 (GPX4), the as-prepared SPIO-based nanoenzyme efficiently improved the ferroptosis efficacy on MDA-MB-231 ​cells. Besides that, the integration of starvation therapy based on Ava modification greatly decreased the expression of CD31, resulted to a nutrient-deprived status and thus significantly enhanced ferroptosis efficacy in a synergistic manner. Concluded from the antitumor investigation on an MDA-MB-231 ​cells xenograft mice model, the systemic administration of this nanoenzyme effectively inhibited the tumor growth and successfully enhanced the mice survival rate. Overall, we believe this biocompatible synergistic ferroptosis-starvation nanoenzyme may provide a refreshing scope to the clinical treatment of TNBC.

Discovery of Sulforaphane as an Inducer of Ferroptosis in U-937 Leukemia Cells: Expanding Its Anticancer Potential.

Simple SummaryFerroptosis and necroptosis are two non-apoptotic programmed cell death pathways with increasing therapeutic potential. The isothiocyanate sulforaphane (SFN) is a well-known naturally derived anticancer compound with remarkable pro-apoptotic activity. Its ability to promote non-apoptotic cell death mechanisms remains poorly investigated. This work discovered that SFN activates apoptosis and ferroptosis dose-dependently in acute myeloid leukemia cells. At lower concentrations, SFN induces caspase-dependent apoptosis. At higher concentrations, ferroptosis is activated and accompanied by the depletion of intracellular glutathione (GSH) and decreased GSH peroxidase 4 protein expression levels. Necroptosis, instead, is not involved in SFN-induced cell death. Considering that cancer cells resist pro-apoptotic treatments, SFN’s ability to induce different types of cell death delineates it as a promising anticancer agent.In recent years, natural compounds have emerged as inducers of non-canonical cell death. The isothiocyanate sulforaphane (SFN) is a well-known natural anticancer compound with remarkable pro-apoptotic activity. Its ability to promote non-apoptotic cell-death mechanisms remains poorly investigated. This work aimed to explore the capacity of SFN to induce non-apoptotic cell death modalities. SFN was tested on different acute myeloid leukemia cell lines. The mechanism of cell death was investigated using a multi-parametric approach including fluorescence microscopy, western blotting, and flow cytometry. SFN triggered different cell-death modalities in a dose-dependent manner. At 25 μM, SFN induced caspase-dependent apoptosis and at 50 μM ferroptosis was induced through depletion of glutathione (GSH), decreased GSH peroxidase 4 protein expression, and lipid peroxidation. In contrast, necroptosis was not involved in SFN-induced cell death, as demonstrated by the non-significant increase in phosphorylation of receptor-interacting protein kinase 3 and phosphorylation of the necroptotic effector mixed lineage kinase domain-like pseudokinase. Taken together, our results suggest that the antileukemic activity of SFN can be mediated via both ferroptotic and apoptotic cell death modalities.

The JAK inhibitor ruxolitinib abrogates immune hepatitis instigated by concanavalin A in mice

Therapeutics that impair the innate immune responses of the liver during the inflammatory cytokine storm like that occurring in COVID-19 are greatly needed. Much interest is currently directed toward Janus kinase (JAK) inhibitors as potential candidates to mitigate this life-threatening complication. Accordingly, this study investigated the influence of the novel JAK inhibitor ruxolitinib (RXB) on concanavalin A (Con A)-induced hepatitis and systemic hyperinflammation in mice to simulate the context occurring in COVID-19 patients. Mice were orally treated with RXB (75 and 150 mg/kg) 2 h prior to the intravenous administration of Con A (20 mg/kg) for a period of 12 h. The results showed that RXB pretreatments were efficient in abrogating Con A-instigated hepatocellular injury (ALT, AST, LDH), necrosis (histopathology), apoptosis (cleaved caspase-3) and nuclear proliferation due to damage (PCNA). The protective mechanism of RXB were attributed to i) prevention of Con A-enhanced hepatic production and systemic release of the proinflammatory cytokines TNF-α, IFN-γ and IL-17A, which coincided with decreasing infiltration of immune cells (monocytes, neutrophils), ii) reducing Con A-induced hepatic overexpression of IL-1β and CD98 alongside NF-κB activation, and iii) lessening Con A-induced consumption of GSH and GSH peroxidase and generation of oxidative stress products (MDA, 4-HNE, NOx) in the liver. In summary, JAK inhibition by RXB led to eminent protection of the liver against Con A-deleterious manifestations primarily via curbing the inflammatory cytokine storm driven by TNF-α, IFN-γ and IL-17A.

Levels of glutathione-related antioxidants in some tissues of stressed Wistar rats

Objectives: Oxidative stress (OS)-related pathologic conditions in the tissues of living organism have been linked to exposure to stressful events within the environment. This study examined the impact of different kinds of stress exposure on glutathione (GSH)-related antioxidants. The effect of stress was examined using comparative levels of GSH, glutathione-S-transferase (GST) and glutathione peroxidase (GPx) in female Wistar rats. Materials and Methods: One hundred and sixty-eight adult female Wistar rats with body weights ranging between 150 and 200 g, were used for the study. The animals were distributed into 28 groups of six animals each. The experimental animals were routinely exposed to three different stressors; restraint chamber test, mirror chamber test and intruder chamber test for a duration of 1, 3 or 5 h per day for 1, 2 and 3 weeks, respectively. All animals were allowed free access to food (rat chaws), with water ad libitum. Animals were euthanise through cervical dislocation after the experimental period and the different target tissues were carefully harvested and homogenised for antioxidant estimation following standard procedure. Data obtained were statistically analysed and values expressed as mean ± standard error of mean and P &lt; 0.05 level was considered as statistically significant. Results: Findings from this study elucidated the fact that exposure to stress is capable of causing marked OS and reducing GSH-based antioxidant activities in Wistar rats. A decline in the GSH level and GPx activity as observed in the study is an indication of alterations of kidney and brain tissue cellular integrity by free radicals generated during exposure to the stressors, while the observed significant increase in GST activity level in the affected tissues indicates compromised rapid exhaustion of the cellular system. Conclusion: Hence, we conclude that stress of different nature, intensity and duration can alter the levels of GSH-related antioxidants, especially in the kidney, ovary and brain tissues of stressed Wistar rats. The GSH levels in liver tissues were observed not to have changed significantly despite the oxidative damage caused by the stressors.

Downregulation of Glutathione-Mediated Detoxification Capacity by Binge Drinking Aggravates Acetaminophen-Induced Liver Injury through IRE1α ER Stress Signaling.

Overdose of acetaminophen (APAP) can cause severe liver injury. Although alcohol is considered a risk factor for APAP toxicity, the mechanism underlying the interaction between alcohol and APAP remains unclear. Binge alcohol (5 g/kg every 12 h, 3 doses) reduced the concentration of cysteine and glutathione (GSH) and decreased expression of cystathionine β-synthase (CβS), cystathionine γ-lyase (CγL), and glutamate cysteine ligase catalytic subunit (GCLC) in the livers of male C57BL/6 mice. Furthermore, the levels of GSH S-transferase (GST) and GSH peroxidase (GPx) were decreased. To evaluate the effect of binge drinking on APAP-induced liver injury, 300 mg APAP was administered following alcohol binges. APAP in the binge group significantly amplified the serum ALT more than two fold and enhanced the pro-apoptotic proteins with a severe centrilobular necrosis compared to APAP alone. APAP treatment after alcohol binges caused lower levels of hepatic cysteine and GSH than APAP alone over 24 h, indicating that alcohol binges reduced GSH regenerating potential. Exposure to APAP after binge treatment significantly increased oxidative stress (lipid peroxidation) and endoplasmic reticulum (ER) stress (Grp78 and ATF6) markers at 6 h after treatment. Notably, the IRE1α/ASK1/MKK4/JNK pathway was activated, whereas CHOP expression was reduced by APAP administration in mice with pre-exposed alcohol binges compared with APAP alone. Thus, pretreatment with binge alcohol decreases GSH-mediated antioxidant capacity and contributes to augmentation of liver injury caused by subsequent APAP administration through differential ER stress signaling pathway.

Boosting Chemodynamic Therapy via a Synergy of Hypothermal Ablation and Oxidation Resistance Reduction.

Chemodynamic therapy (CDT), deemed as a cutting-edge antineoplastic therapeutic tactics, efficaciously suppresses tumors via catalytically yielding hydroxyl radicals (•OH) in tumor regions. Nevertheless, its biomedical applications are often restricted by the limited hydrogen peroxide (H2O2) level and upregulated antioxidant defense. Herein, a versatile nanoreactor is elaborately designed via integrating Cu2-xS and MnO2 for T1-weighted magnetic resonance (MR) imaging-guided CDT, synergistically enhanced through hypothermal ablation and oxidation resistance reduction, thereby displaying splendid antitumor efficiency as well as suppression on pulmonary metastasis. The as-synthesized Cu2-xS@MnO2 nanoreactors afford acid-dependent Cu-based and glutathione (GSH)-activated Mn-based catalytic properties for bimodal CDT. Owing to excellent absorbance at the second near-infrared (NIR-II) window, the Cu2-xS furnishes hypo-photo-thermal therapy (PTT) against tumor growth and ameliorates the catalytic performance for thermal-enhanced CDT. Additionally, MnO2 significantly downregulates GSH and glutathione peroxidase 4, which synergistically boosts CDT via promoting oxidative stress, simultaneously generating Mn2+ for MR contrast improvement and activatable tumor imaging. Therefore, this study proffers a new attempt centered on the collaborative strategy integrating NIR-II hypothermal PTT and synergistically enhanced CDT for tumor eradication.

Dietary supplementation of fructo-oligosaccharides alleviates enterotoxigenic E. coli-induced disruption of intestinal epithelium in a weaned piglet model.

Diarrhoea caused by pathogens such as enterotoxigenic E. coli (ETEC) is a serious threat to the health of young animals and human infants. Here, we investigated the protective effect of fructo-oligosaccharides (FOS) on the intestinal epithelium with ETEC challenge in a weaned piglet model. Twenty-four weaned piglets were randomly divided into three groups: (1) non-ETEC-challenged control (CON); (2) ETEC-challenged control (ECON); and (3) ETEC challenge + 2·5 g/kg FOS (EFOS). On day 19, the CON pigs were orally infused with sterile culture, while the ECON and EFOS pigs were orally infused with active ETEC (2·5 × 109 colony-forming units). On day 21, pigs were slaughtered to collect venous blood and small intestine. Result showed that the pre-treatment of FOS improved the antioxidant capacity and the integrity of intestinal barrier in the ETEC-challenged pigs without affecting their growth performance. Specifically, compared with ECON pigs, the level of GSH peroxidase and catalase in the plasma and intestinal mucosa of EFOS pigs was increased (P < 0·05), and the intestinal barrier marked by zonula occluden-1 and plasmatic diamine oxidase was also improved in EFOS pigs. A lower level (P < 0·05) of inflammatory cytokines in the intestinal mucosa of EFOS pigs might be involved in the inhibition of TLR4/MYD88/NF-κB pathway. The apoptosis of jejunal cells in EFOS pigs was also lower than that in ECON pigs (P < 0·05). Our findings provide convincing evidence of possible prebiotic and protective effect of FOS on the maintenance of intestinal epithelial function under the attack of pathogens.

The Ferroptosis-NLRP1 Inflammasome: The Vicious Cycle of an Adverse Pregnancy.

One of the hallmarks of placental dysfunction is the increase of oxidative stress. This process, along with the overexpression of the inflammasome, creates a downward spiral that can lead to a series of severe pregnancy complications. Ferroptosis is a form of iron-mediated cell death involving the accumulation of reactive oxygen species, lipid peroxides. In this study, the rats’ model of oxidative stress abortion was established, and hydrogen peroxide (H2O2) was used to establish a cellular model of placental oxidative stress. RNAi, western blot, and immunofluorescence were used to evaluate the expression of specific markers of ferroptosis and the expression of the inflammasome in placental trophoblast cells. We observed excessive levels of ferroptosis and inflammasome activation in both rats’ model and placental trophoblast cell model of oxidative stress. When the NLRP1 inflammasome was silenced, the expression levels of GSH and Glutathione peroxidase 4 (GPX4) were increased, while the expression levels of transferrin receptor 1 (TFR1), acyl-CoA synthetase long-chain family member 4 (ACSL4), Superoxide dismutase (SOD), and Malondialdehyde (MDA) were decreased. However, when an NLRP1 activator was applied, we observed the opposite phenomenon. We further explored the mechanisms underlying the actions of ferroptosis to inflammasomes. The expression levels of NLRP1, NLRP3, IL-1β, and caspase-1 were positively correlated with the ferroptosis following the application of ferroptosis inhibitor (ferrostatin-1) and ferroptosis activator (erastin). The existence of ferroptosis was demonstrated in the oxidative stress model of placental trophoblast cells; the results also indicate ferroptosis is linked with the expression of NLRP1 inflammasome. These findings may provide a valuable therapeutic target for the pathogenesis of pregnancy-related diseases.

Copper single-atom catalysts with photothermal performance and enhanced nanozyme activity for bacteria‐infected wound therapy

Nanozymes have become a new generation of antibiotics with exciting broad-spectrum antibacterial properties and negligible biological toxicity. However, their inherent low catalytic activity limits their antibacterial properties. Herein, Cu single-atom sites/N doped porous carbon (Cu SASs/NPC) is successfully constructed for photothermal-catalytic antibacterial treatment by a pyrolysis-etching-adsorption-pyrolysis (PEAP) strategy. Cu SASs/NPC have stronger peroxidase-like catalytic activity, glutathione (GSH)-depleting function, and photothermal property compared with non-Cu-doped NPC, indicating that Cu doping significantly improves the catalytic performance of nanozymes. Cu SASs/NPC can effectively induce peroxidase-like activity in the presence of H2O2, thereby generating a large amount of hydroxyl radicals (•OH), which have a certain killing effect on bacteria and make bacteria more susceptible to temperature. The introduction of near-infrared (NIR) light can generate hyperthermia to fight bacteria, and enhance the peroxidase-like catalytic activity, thereby generating additional •OH to destroy bacteria. Interestingly, Cu SASs/NPC can act as GSH peroxidase (GSH-Px)-like nanozymes, which can deplete GSH in bacteria, thereby significantly improving the sterilization effect. PTT-catalytic synergistic antibacterial strategy produces almost 100% antibacterial efficiency against Escherichia coli (E. coli) and methicillin-resistant Staphylococcus aureus (MRSA). In vivo experiments show a better PTT-catalytic synergistic therapeutic performance on MRSA-infected mouse wounds. Overall, our work highlights the wide antibacterial and anti-infective bio-applications of Cu single-atom-containing catalysts.

Glutathione Metabolism and the Novel Role of Mitochondrial GSH in Retinal Degeneration.

Glutathione (GSH) is present ubiquitously, and its role as a crucial cellular antioxidant in tissues, including the retina, is well established. GSH’s antioxidant function arises from its ability to scavenge reactive oxygen species or to serve as an essential cofactor for GSH S-transferases and peroxidases. This review summarizes the general functions, retinal distribution, disorders linked to GSH deficiency, and the emerging role for mitochondrial GSH (mGSH) in retinal function. Though synthesized only in the cytosol, the presence of GSH in multiple cell organelles suggests the requirement for its active transport across organellar membranes. The localization and distribution of 2-oxoglutarate carrier (OGC) and dicarboxylate carrier (DIC), two recently characterized mitochondrial carrier proteins in RPE and retina, show that these transporters are highly expressed in human retinal pigment epithelium (RPE) cells and retinal layers, and their expression increases with RPE polarity in cultured cells. Depletion of mGSH levels via inhibition of the two transporters resulted in reduced mitochondrial bioenergetic parameters (basal respiration, ATP production, maximal respiration, and spare respiratory capacity) and increased RPE cell death. These results begin to reveal a critical role for mGSH in maintaining RPE bioenergetics and cell health. Thus, augmentation of mGSH pool under GSH-deficient conditions may be a valuable tool in treating retinal disorders, such as age-related macular degeneration and optic neuropathies, whose pathologies have been associated with mitochondrial dysfunction.

Investigating intrinsic radiosensitivity biomarkers to peptide receptor radionuclide therapy with [177Lu]Lu-DOTATATE in a panel of cancer cell lines

Introduction[177Lu]Lu-DOTATATE is an effective systemic targeted radionuclide therapy for somatostatin receptor (SSTR) positive metastatic or inoperable neuroendocrine tumours (NET). However, for a given injected activity, tumour responses are variable. Our aim was to investigate whether SSTR expression/functionality and known characteristics of intrinsic radiosensitivity, namely proliferation rate, glucose metabolism, cell cycle phase, DNA repair and antioxidant defences were predictors of sensitivity to [177Lu]Lu-DOTATATE in SSTR expressing human cancer cell lines. MethodsIn six human cancer cell lines and under basal condition, SSTR expression was assessed by qRT-PCR and immunocytochemistry. Its functionality was evaluated by binding/uptake assays with [68Ga]Ga- and [177Lu]Lu-DOTATATE. The radiosensitivity parameters were evaluated as follows: proliferation rate (cell counting), glucose metabolism ([18F]FDG uptake), antioxidant defences (qRT-PCR, colorimetric assay, flow cytometry), DNA repair (qRT-PCR) and cell cycle (flow cytometry). Effect of [177Lu]Lu-DOTATATE on cell viability was assessed 3, 7 and 10 days after 4 h incubation with [177Lu]Lu-DOTATATE using crystal violet. ResultsBased on cell survival at day 10, cell lines were classified into two groups of sensitivity to [177Lu]Lu-DOTATATE. One group with <20% of survival decrease (−14 to −1%) and one group with >20% of survival decrease (−22 to −33%) compared to the untreated control cell lines. The latter had significantly lower total antioxidant capacity, glutathione (GSH) levels and glucose metabolism (p < 0.05) compared to the first group. SSTR (p = 0.64), proliferation rate (p = 0.74), cell cycle phase (p = 0.55), DNA repair (p > 0.22), combined catalase and GSH peroxidase expression (p = 0.42) and superoxide dismutase (SOD) activity (p = 0.41) were not significantly different between the two groups. ConclusionAntioxidant defences may be major determinants in [177Lu]Lu-DOTATATE radiosensitivity.