Glutathione Peroxidase Research Articles

Effects of inactivated Lactobacillus rhamnosus on growth performance, serum indicators, and colonic microbiota and metabolism of weaned piglets

BackgroundTo assess the effects of inactivated Lactobacillus rhamnosus (ILR) on growth performance, serum biochemical indices, colonic microbiota, and metabolomics in weaned piglets, 120 piglets were randomly divided into five groups. Samples in the control group were fed a basal diet, while the experimental ILR1, ILR2, ILR3, and ILR4 groups were fed basal diets supplemented with 0.1%, 0.2%, 0.3%, and 0.4% ILR, respectively. The prefeeding period lasted for 5 days and was followed by a formal period of 28 days.ResultsCompared to the control, the average daily gain increased by 4.38%, 7.98%, 19.32%, and 18.80% for ILR1, ILR2, ILR3, and ILR4, respectively, and the ratio of feed to gain decreased by 0.63%, 3.80%, 12.66%, and 10.76%, respectively. Serum IgA, IgG, IgM, total antioxidant capacity, and glutathione peroxidase levels increased significantly in weaned piglets in the treatment groups. Addition of 0.3% ILR significantly increased the Shannon and Simpson indices of the colonic microbiota in weaned piglets and altered the microbiota composition. Changes in metabolic profiles were observed and were primarily related to the urea cycle, amino acid metabolism, and lipid metabolism.ConclusionILR improved growth performance and serum immunological and biochemical indices and optimized the colonic microbiota structure and metabolism of weaned piglets.

NIR‐Triggered Cu2O/Cu2‐xS Heterostructure as an “All‐In‐One” Functional Nanoplatform for Efficient Synergistic Tumor Therapy

AbstractThe fabrication of synergistic multifunctional anti‐tumor nanoplatforms is challenging due to the urgent requirement to activate different therapeutic modalities. Although the multi‐modal treatments can be achieved by carrying out the activation with different exogenous and endogenous stimulations in sequence, this tedious manner is not applicable to the ideal synergistic cancer treatment. Herein, a simple heterojunction of Cu2O/Cu2‐xS modified with gambogic acid and hyaluronic acid (CCS@GA@HA) is ingeniously fabricated for the synergistic cancer treatment combining photothermal therapy (PTT), photocatalytic therapy (PCT), chemodynamic therapy (CDT) and potential ferroptosis just activated by the single near infrared (NIR) light irradiation. Cu2O/Cu2‐xS heterostructure (CCS) with promoted separation and transfer efficiency of photogenerated charge carriers exhibits excellent photocatalytic performance. The intervention of gambogic acid (GA) downregulates the overexpression of heat shock protein 90 (HSP90), which make it possible to execute the mild PTT. And the CDT performance is efficiently improved by the heat generated from PTT. Specifically, CCS appears to accelerate the accumulation of lipid peroxides (LPO) and inactivate glutathione peroxidase 4 (GPX4) that directly induce ferroptosis. In brief, CCS@GA@HA exhibits prominent NIR‐triggered synergistic effect involving PCT, mild PTT, enhanced CDT and ferroptosis for an effective multi‐modal tumor treatment.

Possible protective effect of remifentanil against testicular ischemia-reperfusion injury

Abstract Objectives This study aims to evaluate the protective efficacy of remifentanil against testicular ischemia-reperfusion injury. Methods The study included 24 male rats. The rats were randomized into three groups: Group 1 was the control group. Group 2 was subjected to a testicular torsion/detorsion model. Group 3 underwent similar procedures and additionally received remifentanil (0.6 μg/kg/min) intravenously for the first 20 min of reperfusion. Blood samples were taken for biochemical analyses, and orchiectomy was performed for histopathologic examination. Results Biochemical analysis of blood samples showed a significant increase in antioxidant enzyme activity, including superoxide dismutase (SOD) and glutathione peroxidase (GSH-Px) in Group 3 compared to Group 2 (p:0.004 and p:0.002, respectively). There was a dramatic decrease in the levels of proinflammatory cytokines, including interleukin-1 beta (IL-1 Beta), interleukin-6 (IL-6), and tumor necrosis factor-alpha (TNF-alpha) in Group 3 compared to Group 2 (p:0.001, p:0.046, and p:0.004, respectively). Similarly, malondialdehyde (MDA) levels decreased in Group 3 compared to Group 2 (p:0.004). Histopathologic examination of Group 3 rats showed positive changes in inflammation, hemorrhage, edema, and congestion levels compared to Group 2 (p<0.001). Similarly, there was a positive effect on the Johnsen and Cosentino score in Group 3 compared to Group 2 (p:0.001 and p<0.001, respectively). Conclusions In our study, it has been documented that remifentanil protects against testicular ischemia-reperfusion injury.

Effect of Morchella esculenta polysaccharides on the rectal microbiota of mice challenged with lipopolysaccharides

IntroductionIntestinal dysfunction poses a severe problem by preventing the digestion and absorption of nutrients. The gut, being the most vital organ for these processes, plays a crucial role in ensuring our body receives the nutrients it needs. We explored the mitigating effect of Morchella esculenta polysaccharides (MEP) on intestinal injury induced by lipopolysaccharides (LPS) through the modulation of intestinal flora.MethodsFor this purpose, Kunming mice (KM) were divided into three groups, namely, PC, PM, and PY. Group PY was treated with MEP, while groups PM and PY were induced with LPS.ResultsThe results showed that weight loss in the PM group was significantly greater than that in the PY group (P < 0.05), and the organ indexes of the lung and spleen in the PM group were significantly higher than those in the PC (P < 0.01) and PY (P < 0.05) groups. LPS caused severe injuries in KM mice in the PM group, characterized by broken villi. However, MEP treatment could alleviate this damage in the PY group, resulting in relatively intact villi. The serum analysis showed that tumor necrosis factor alpha (TNF-ɑ) (P < 0.01), interleukin 6 (IL-6) (P < 0.01), and 3,4-methylenedioxyamphetamine (MDA) (P < 0.05) levels were significantly higher in the PM group, while IL-10 (P < 0.001), superoxide dismutase (SOD) (P < 0.01) and glutathione peroxidase (GSH-Px) (P < 0.01) were significantly lower in that group. Interestingly, supplementation with MEP could lower the levels of TNF-ɑ, IL-10, IL-6, MDA while increasing the levels of superoxide dismutase (SOD) (P < 0.01) and GSH-Px. The gut microbiota analysis yielded 630,323 raw reads and 554,062 clean reads, identifying 3,390 amplicon sequencing variants (ASVs). One phylum and five genera were notably different among animal groups, including Escherichia_Shigella, Limosilactobacillus, unclassified_Geminicoccaceae, unclassified_Rhodobacteraceae, and Parabacteroides (P. distasonis).DiscussionIn conclusion, we found that MEP could mitigate the intestinal damage caused by LPS by modulating the inflammatory response, oxidative resistance, and intestinal flora of KM mice. Our results may provide insights into novel treatment options for intestine-related diseases.

All‐Atom Protein Sequence Design Based on Geometric Deep Learning

Designing sequences for specific protein backbones is a key step in creating new functional proteins. Here, we introduce GeoSeqBuilder, a deep learning framework that integrates protein sequence generation with side chain conformation prediction to produce the complete all‐atom structures for designed sequences. GeoSeqBuilder uses spatial geometric features from protein backbones and explicitly includes three‐body interactions of neighboring residues. GeoSeqBuilder achieves native residue type recovery rate of 51.6%, comparable to ProteinMPNN and other leading methods, while accurately predicting side chain conformations. We first used GeoSeqBuilder to design sequences for thioredoxin and a hallucinated three‐helical bundle protein. All the 15 tested sequences expressed as soluble monomeric proteins with high thermal stability, and the 2 high‐resolution crystal structures solved closely match the designed models. The generated protein sequences exhibit low similarity (minimum 23%) to the original sequences, with significantly altered hydrophobic cores. We further redesigned the hydrophobic core of glutathione peroxidase 4, and 3 of the 5 designs showed improved enzyme activity. Although further testing is needed, the high experimental success rate in our testing demonstrates that GeoSeqBuilder is a powerful tool for designing novel sequences for predefined protein structures with atomic details. GeoSeqBuilder is available at https://github.com/PKUliujl/GeoSeqBuilder

All-Atom Protein Sequence Design Based on Geometric Deep Learning.

Designing sequences for specific protein backbones is a keystep in creating new functional proteins. Here, we introduceGeoSeqBuilder, a deep learning framework that integratesprotein sequence generation with side chain conformationprediction to produce the complete all-atom structures fordesigned sequences. GeoSeqBuilder uses spatial geometricfeatures from protein backbones and explicitly includesthree-body interactions of neighboring residues. GeoSeqBuilderachieves native residue type recovery rate of 51.6%,comparable to ProteinMPNN and otherleadingmethods,while accurately predicting side chain conformations. Wefirst used GeoSeqBuilder to design sequences for thioredoxinand a hallucinated three-helical bundle protein. All the15 tested sequences expressed as soluble monomeric proteinswith high thermal stability, and the 2 high-resolutioncrystal structures solved closely match the designed models.The generated protein sequences exhibit low similarity(minimum 23%) to the original sequences, with significantlyaltered hydrophobic cores. We further redesigned the hydrophobiccore of glutathione peroxidase 4, and 3 of the 5designs showed improved enzyme activity. Although furthertesting is needed, the high experimental success ratein our testing demonstrates that GeoSeqBuilder is a powerfultool for designing novel sequences for predefined proteinstructures with atomic details. GeoSeqBuilder is availableat https://github.com/PKUliujl/GeoSeqBuilder.

Targeting ferroptosis for improved radiotherapy outcomes in HPV‐negative head and neck squamous cell carcinoma

To enhance the efficacy of radiotherapy (RT) in human papillomavirus (HPV)‐negative head and neck squamous cell carcinoma (HNSCC), we explored targeting ferroptosis, a regulated cell death process. We developed a gene signature associated with ferroptosis using Cox proportional hazard modeling in HPV‐negative HNSCC patients who underwent RT. This ferroptosis‐related gene signature (FRGS) was a significant predictor of overall survival and recurrence‐free survival in HPV‐negative HNSCC patients who received RT. Subtype B of the FRGS, characterized by decreased expression of ferroptosis inducers [nuclear receptor coactivator 4 (NCOA4) and natural resistance‐associated macrophage protein 2 homolog/divalent metal transporter 1 (NRAMP2/DMT1)] and increased expression of suppressors [phospholipid hydroperoxide glutathione peroxidase (GPX4) and ferritin heavy chain (FTH1)], was associated with poorer prognosis, potentially indicating the inhibition of ferroptosis. Furthermore, our in vitro and in vivo studies demonstrated that treatment with statins, such as atorvastatin and simvastatin, induced ferroptosis and sensitized radioresistant HNSCC cells to irradiation, improving radiosensitivity and potentially enhancing the response to RT. Additionally, in xenograft models, the combination of statins and RT led to a significant reduction in tumor initiation. These findings provide valuable insights for enhancing treatment and improving prognosis in HPV‐negative HNSCC by targeting ferroptosis and utilizing statins to sensitize tumors to RT‐induced cell death.

Knockdown of USP7 alleviates atherosclerosis in ApoE-deficient mice by regulating EZH2 expression

Abstract Atherosclerosis (AS) is a chronic vascular disease associated with lipid accumulation. Understanding the molecular mechanisms of AS is essential. Ubiquitin-specific protease 7 (USP7) is a deubiquitination enzyme involved in various cellular processes, including lipid metabolism. In this study, we aimed to elucidate the role of USP7 in AS progression and its underlying mechanism using ApoE-deficient mice. We found that USP7 ablation improved the morphological characteristics of AS in these mice. USP7 knockdown reduced inflammation, evidenced by decreases in inflammatory markers IL-6, TNF-α, and IL-1β by 35, 40, and 38%, respectively (p < 0.01). Additionally, USP7 depletion reduced oxidative stress, indicated by a 30% reduction in malondialdehyde levels and increases in superoxide dismutase and glutathione peroxidase levels by 25 and 28%, respectively (p < 0.01). Moreover, USP7 knockdown blocked lipid accumulation in aortic tissue cells. Mechanistically, USP7 knockdown inhibited enhancer of Zeste Homolog 2 (EZH2) expression, thereby suppressing AS progression. In conclusion, USP7 depletion alleviated AS progression in ApoE-deficient mice by targeting EZH2 expression. USP7 may serve as a therapeutic target for AS.

Resveratrol Protects Müller Cells Against Ferroptosis in the Early Stage of Diabetic Retinopathy by Regulating the Nrf2/GPx4/PTGS2 Pathway.

The aim of this study was to investigate the anti-ferroptotic effect of resveratrol (RSV) on retinal Müller cells (RMCs) in the early stages of diabetic retinopathy (DR) via the nuclear factor erythroid 2-related factor 2 (Nrf2)/glutathione peroxidase 4 (GPx4)/prostaglandin-endoperoxide synthase 2 (PTGS2). The retina was obtained from normal and diabetic Sprague-Dawley rats or wild-type and Nrf2 knockout (KO) diabetic mice, with or without RSV (10mg/kg/d) treatment for 12weeks. RMCs transfected with or without SiNrf2 were cultured with high glucose and RSV (20mM). The retinal neurofunctional changes were measured by electroretinogram (ERG). The retinal inner nuclear layer cell mitochondrial morphological changes were detected by transmission electron microscopy. The cell viabilities were measured by cell counting kit-8 (CCK-8) assay. The levels of Fe2+, malonic dialdehyde (MDA), and glutathione (GSH) were measured by colorimetric method. The expression of Nrf2, GPx4, and PTGS2 was detected by quantitative real-time polymerase chain reaction (qRT-PCR), western blotting, and immunocytochemistry. In vivo, RSV inhibited retinal neurofunctional changes and mitochondrial morphological changes; decreased Fe2+, MDA, and PTGS2; and increased GSH, Nrf2, and GPx4 in retina of DM rats. In vitro, RSV decreased MDA and PTGS2 and increased cell viability, GSH, Nrf2, and GPx4. In vivo and vitro, the role of Nrf2-regulated signaling pathway in anti-ferroptosis by RSV was further confirmed using Nrf2 KO mice and pre-transfected SiNrf2 in RMCs. These findings indicated that RSV is a potential therapeutic option for DR and that Nrf2/GPx4/PTGS2 plays a role in the anti-ferroptosis mechanism of RSV on RMCs.

Etomidate protects retinal ganglion cells from hydrogen peroxide-induced injury via Nrf2/HO-1 pathway.

To determine whether etomidate (ET) has a protective effect on retinal ganglion cells (RGCs) injured with hydrogen peroxide (H2O2) and to explore the potential mechanism underlying the antioxidative stress effect of ET. Cultured RGCs were identified by double immunofluorescent labeling of microtubule-associated protein 2 and Thy1.1. An injury model of H2O2-induced RGCs oxidative stress was established in vitro. Cells were pretreated with different concentrations of ET (1, 5, and 10 µmol/L) for 4h, followed by further exposure to H2O2 at 1000 µmol/L. Cell counting kit 8 and Annexin V/propidium iodide assays were applied to detect the viabilities and apoptosis rates of the RGCs at 12, 24, and 48h after H2O2 stimulation. The levels of nitric oxide, malondialdehyde, and glutathione in culture media were measured at these time points. Quantitative reverse transcription polymerase chain reaction (qRT-PCR) and Western blot were performed to observe the effects of ET on the messenger RNA and protein expression of inducible nitric oxide synthase (iNOS), nuclear factor erythroid 2-related factor 2 (Nrf2), heme oxygenase 1 (HO-1), glutathione peroxidase 1 and the level of conjugated acrolein in RGCs at 12, 24, and 48h after H2O2 stimulation and in the retina at 12h after optic nerve transection (ONT). The applications of 5 and 10 µmol/L of ET significantly increased the viability of RGCs. Results from qRT-PCR indicated a decrease in the expression of iNOS and an increase in the expressions of Nrf2 and HO-1 in ET-pretreated RGCs at 12, 24 and 48h after H2O2 stimulation, as well as in ET-treated retinas at 12h after ONT. Western blot analysis revealed a decrease in the expression of iNOS and levels of conjugated acrolein, along with an increase in the expressions of Nrf2 and HO-1 in ET-pretreated RGCs in vitro and ET-treated retinas in vivo. ET is a neuroprotective agent in primary cultured RGCs injured by H2O2. The effect of ET is dose-dependent with the greatest effect being at 10 µmol/L. ET plays an antioxidant role by inhibiting iNOS, up-regulating Nrf2/HO-1, decreasing the production of acrolein, and increasing the scavenge of acrolein.

Impact of weight variation on the microbiome of yak dams and calves

IntroductionLimited information exists regarding the microbiome composition of yak calves of varying weights. Therefore, this study aimed to investigate the microbiomes of mother-calf pairs with different weight profiles.MethodsFecal and blood samples were collected from both lower-weight (CB) and higher-weight (HB) yak calves, along with their corresponding female yaks (CA, HA).ResultsThe results revealed significantly higher levels of T-AOC (total antioxidant capacity) and GSH-Px (glutathione peroxidase) in HB animals (p < 0.001). Sequencing yielded 652,181 and 643,369 filtered reads in female and calf yaks, respectively. Alpha diversity analysis indicated that Chao1, Faith_pd, and Observed species were significantly higher in CA compared to HA (p < 0.01). Furthermore, nine genera were notably different between HA and CA yaks, including Avispirillum, Fimenecus, CAG-1031, Odoribacter 865974, and Jeotgalicoccus A 310962. Compared to CB yaks, CA animals exhibited significant differences in one phylum and six genera, including CAG-485 (p < 0.05), CAG-83 (p < 0.01), Copromorpha (p < 0.01), Phocaeicola A 858004 (p < 0.05), and UBA2253 (p < 0.05).ConclusionIn summary, higher-weight yak calves demonstrated increased oxidative resistance, and weight profiles were linked to the microbiomes of both female yaks and their calves. These findings offer valuable insights for optimizing yak breeding practices in high-altitude regions.

Short-term Uridine Treatment Alleviates Endoplasmic Reticulum Stress via Regulating Inflammation and Oxidative Stress in Lithium-Pilocarpine Model of Status Epilepticus

Background: Status Epilepticus (SE) leads to the development of epilepsy with the contribution of Endoplasmic Reticulum (ER) stress. Uridine, a pyrimidine nucleoside, has been shown to have neuroprotective and antiepileptogenic effects in animal models. This study aimed to determine whether uridine ameliorates ER stress and apoptosis following epileptogenic insult. Secondly, this study aimed to establish the effect of uridine on inflammatory and oxidative stress parameters that contribute to ER stress. Methods: Status epilepticus was induced using lithium-pilocarpine in adult male Sprague-Dawley rats. Following SE termination, rats were treated with uridine, 4-phenylbutyric acid (4-PBA), or saline twice daily for 48 h. Expressions of hippocampal glucose-regulated protein 78 (GRP78), Inositol- Requiring Protein 1 (IRE1α), Protein kinase RNA-like Endoplasmic Reticulum Kinase (PERK), and C/EBP Homologous Protein (CHOP) were determined by western blotting 48 h after SE. Uridine's effects on apoptosis, inflammation or oxidation were evaluated by analyses of cleaved caspase-3 and poly(ADP-ribose) polymerase 1 (PARP1) protein expressions or pro-inflammatory cytokine levels or levels of oxidative stress markers, respectively. Results: Expressions of all ER stress-related proteins significantly increased 48 h after SE. Uridine treatment markedly decreased GRP78, IRE1α, and CHOP levels. A decrease in the PERK level was observed following the administration of 4-PBA; however, uridine had no effect. Cleaved caspase-3 and PARP1 levels were increased in the SHAM group, while uridine and 4-PBA treatment effectively decreased their expressions. Treatment with uridine significantly reduced Myeloperoxidase (MPO) and Malondialdehyde (MDA) levels while tending to increase Catalase (CAT) and Glutathione Peroxidase (GPx) levels. Uridine treatment also significantly attenuated levels of TNF-α and IL-1β, the pro-inflammatory cytokines, which increased 48 h post-SE. Conclusion: Our data indicate that uridine alleviates ER stress after SE. This effect may be attributed to the regulation of inflammation and oxidative stress. Uridine shows promise as a potential preventive agent for epilepsy.

Protective effect of propolis in protecting against radiation-induced oxidative stress in the liver as a distant organ

Stresses caused by ionizing radiation can also damage tissues and organs through the circulatory system. In this study, we aimed to determine the radioprotective effect of propolis, a natural and powerful antioxidant product, against oxidative liver damage caused by cranial irradiation. Thirty-two male albino Sprague–Dawley rats, divided into four groups, were designed as sham group, irradiation (IR) group, propolis plus IR, control group of propolis. Biochemical parameters were measured in liver tissue of rats. While Total enzymatic superoxide scavenging activity (TSSA) and non-enzymatic superoxide scavenging activity (NSSA), glutathione peroxidase (GSH-Px) activities of all groups were statistically significantly higher than rats receiving only-irradiation, Glutathione-S-transferase (GST) activity in the IR group was significantly lower than in the sham control group and IR + propolis group. Superoxide dismutase (SOD) activity in the IR group was found to be significantly higher than both the sham control group and the propolis control group, but lower than the IR + propolis group. Malondialdehyde level and xanthine oxidase activity were higher in the IR group than in the other groups. Compared to the sham control group, in the group treated with propolis, a significant elevation in antioxidant parameters, specifically TSSA, NSSA, SOD, and GST activities, was noted, with corresponding increases of 32.3%, 23.2%, 47.6%, and 22.6%, respectively. Our findings show that propolis can be a radioprotective agent against ionized radiation damage by increasing antioxidant activity and reducing oxidant stress in liver tissue.

Botanical Bioflavonoid Composition from Scutellaria baicalensis- and Acacia catechu-Protected Mice against D-Galactose-Induced Immunosenescence, and Cyclophosphamide Induced Immune Suppression

Oxidative stress and chronic inflammation create a perpetual cycle in the elderly, where impaired immune function amplifies susceptibility to oxidative damage, and oxidative stress further weakens the immune response. This cycle is particularly detrimental to the respiratory system of the elderly, which is an easy target for constant exogenous harmful attacks during cold/flu season or under heavy air pollution. Herbal medicines that protect respiratory function are seen as safer alternatives to conventional therapies; however, there is limited availability of scientifically validated, safe, and effective natural supplements for these conditions. In this study, we evaluated a standardized bioflavonoid composition, UP446, that contains bioactives from the roots of Scutellaria baicalensis and the heartwoods of Acacia catechu as a natural and nutritional supplement for its antioxidative and immunoregulatory effects in oxidative stress-accelerated aging and chemically induced immune suppression mouse models. Immunosenescence was induced through the repeated subcutaneous inoculation of D-galactose (D-Gal) at a dose of 500 mg/kg/day in CD-1 mice. UP446 was administered orally at doses of 100 mg/kg and 200 mg/kg starting in the fifth week of immunosenescence induction. This study lasted a total of ten weeks. All mice received a quadrivalent influenza vaccine 2 weeks before termination. Whole blood, serum, spleen homogenate, and thymus tissues were processed for analysis. Cyclophosphamide (Cy)-induced immunosuppression was triggered by three consecutive injections of cyclophosphamide at 80 mg/kg/day, followed by the oral administration of UP446 for 18 days at doses of 100 mg/kg and 200 mg/kg. Blood was collected from each animal at necropsy, and serum was isolated for IgA and IgG ELISA analysis. UP446 was found to improve immune response, as evidenced by the stimulation of innate (NK cells) and adaptive immune responses (T cells and cytotoxic T cells), an increase in antioxidant capacity (glutathione peroxidase), the preservation of vital immune organs (the thymus), and a reduction in NFκB. UP446 also increased serum levels of IgA and IgG. The findings presented in this report demonstrate the antioxidative, anti-inflammatory, and immune-regulatory activities of UP446, suggesting its potential use in respiratory conditions involving immune stress due to aging, oxidative stress, and/or pathogenic challenges.

Supplementation with carnosine, a food-derived bioactive dipeptide, alleviates dexamethasone-induced oxidative stress and bone impairment via the NRF2 signaling pathway.

Carnosine, a natural bioactive dipeptide derived from meat muscle, possesses strong antioxidant properties. Dexamethasone, widely employed for treating various inflammatory diseases, raises concerns regarding its detrimental effects on bone health. This study aimed to investigate the protective effects of carnosine against dexamethasone-induced oxidative stress and bone impairment, along with its underlying mechanisms, utilizing chick embryos and a zebrafish model in vivo, as well as MC3T3-E1 cells in vitro. Our findings revealed that carnosine effectively mitigated bone injury in dexamethasone-exposed chick embryos, accompanied by reduced oxidative stress. Further investigation demonstrated that carnosine alleviated impaired osteoblastic differentiation in MC3T3-E1 cells and zebrafish by suppressing the excessive production of reactive oxygen species (ROS) and enhancing the activity of antioxidant enzymes such as superoxide dismutase (SOD) and glutathione peroxidase (GPX). Moreover, mechanistic studies elucidated that carnosine promoted the expression and nuclear translocation of nuclear factor erythroid 2-related factor 2 (NRF2), thereby facilitating the transcription of its downstream antioxidant response elements, including heme oxyense-1 (HO-1), glutamate cysteine ligase modifier (GCLM), and glutamate cysteine ligase catalytic (GCLC) to counteract dexamethasone-induced oxidative stress. Overall, this study underscores the potential therapeutic efficacy of carnosine in mitigating oxidative stress and bone damage induced by dexamethasone exposure, shedding light on its underlying mechanism of action by activating the NRF2 signaling pathway. © 2024 Society of Chemical Industry.

Effects of Dietary Supplementation of Zinc Oxide Quantum Dots on Growth Performance and Gut Health in Broilers.

This study aims to investigate the effect of different levels of zinc oxide quantum dots (ZnO-QDs) on the growth performance and gut health in broilers. A total of 1125 1-day-old Ross 308 broilers were randomly divided into five groups with 15 replicates of 15 chicks each. The broilers were fed basal diets supplemented with 0, 40, 80, 120, or 160mg Zn/kg as ZnO-QDs for 6weeks. The results showed that dietary 80 and 120mg Zn/kg ZnO-QD supplementation increased (P < 0.05) average daily gain (1.4-1.7%) and reduced feed conversion ratio (1.3%) compared to the basal diet group during various experimental periods. Meanwhile, 80mg Zn/kg ZnO-QD supplementation increased (P < 0.05) trypsin activity (25.4%), villus height, and the ratio of villus height to crypt depth in the jejunum. Moreover, 80mg Zn/kg ZnO-QD supplementation increased (P < 0.05) the activities of glutathione reductase (47.7%) and superoxide dismutase (30.9%), while 120mg Zn/kg ZnO-QD supplementation decreased (P < 0.05) glutathione peroxidase activity (27.1%) in the jejunum. Furthermore, 40mg Zn/kg ZnO-QD supplementation down-regulated (P < 0.05) the expression of genes; interleukin-2, transforming growth factor β (TGF-β), Cathelicidin-1, Cathelicidin-2, Cathelicidin-3, and Occludin, while 80-160mg Zn/kg ZnO-QD supplementation up-regulated (P < 0.05) Claudin-2 expression in the jejunum. In conclusion, dietary ZnO-QD supplementation improved growth performance of broilers potentially by enhancing their intestinal health status. Based on nonlinear regression analysis, the appropriate level of ZnO-QD supplementation would be from 98.2 to 102.5mg Zn/kg.

Inhibition of Phosphodiesterase 4 Suppresses Neuronal Ferroptosis After Cerebral Ischemia/Reperfusion.

We have previously shown that inhibition of phosphodiesterase 4 (PDE4) protects against cerebral ischemia/reperfusion injury. However, it remains unclear whether and how PDE4 affects ferroptosis under cerebral ischemia/reperfusion conditions. In this study, we found that overexpression of PDE4B in HT-22 cells exacerbated the detrimental effects of oxygen-glucose deprivation/reoxygenation (OGD/R), including a decrease in cell viability and glutathione (GSH) levels and an increase in Fe2+ content. PDE4B knockdown mitigated the effects of OGD/R, as evidenced by decreased oxidative stress, lactate dehydrogenase (LDH) release, Fe2+ content, and nuclear receptor coactivator 4 (NCOA4) expression. PDE4B knockdown also enhanced the levels of GSH, ferroportin (FPN), and ferritin heavy chain 1 (FTH1). Consistently, inhibition of PDE4 by roflumilast (Roflu) produced similar effects as PDE4B knockdown. Roflu also ameliorated the morphology and membrane potential of the mitochondria. Glutathione peroxidase 4 (GPX4) knockdown blocked the effects of Roflu on cell viability and lipid peroxidation. Moreover, we found that nuclear factor erythroid 2-related factor 2 (Nrf-2) knockdown decreased GPX4 expression. In addition, Nrf-2 knockdown led to enhanced lipid peroxidation, LDH release, and iron levels, while the GSH and FPN levels decreased. More crucially, PDE4 inhibition decreased infarct volume, alleviated oxidative stress, and restored the expression levels of ferroptosis-associated proteins in middle cerebral artery occlusion/reperfusion (MCAO/R) rats. Interestingly, the GPX4 inhibitor RSL3 blocked the neuroprotective effects of Roflu in rats subjected to MCAO/R. Thus, PDE4 inhibition significantly inhibits neuronal ferroptosis by activating the Nrf-2/GPX4 pathway. These data indicate the existence of a novel mechanism underlying the neuroprotective effects of PDE4 inhibition.

Glutathione-Disrupting Nanotherapeutics Potentiate Ferroptosis for Treating Luminal Androgen Receptor-Positive Triple-Negative Breast Cancer.

The refractory luminal androgen receptor (LAR) subtype of triple-negative breast cancer (TNBC) patients is challenged by significant resistance to neoadjuvant chemotherapy and increased immunosuppression. Regarding the distinct upregulation of glutathione (GSH) and glutathione peroxidase 4 (GPX4) in LAR TNBC tumors, we herein designed a GSH-depleting phospholipid derivative (BPP) and propose a BPP-based nanotherapeutics of RSL-3 (GDNS), aiming to deplete intracellular GSH and repress GPX4 activity, thereby potentiating ferroptosis for treating LAR-subtype TNBC. GDNS treatment drastically downregulated the expression of GSH and GPX4, resulting in a 33.88-fold enhancement of lipid peroxidation and significant relief of immunosuppression in the 4T1 TNBC model. Moreover, GDNS and its combination with antibody against programed cell death protein 1 (antiPD-1) retarded tumor growth and produced 2.83-fold prolongation of survival in the LAR-positive TNBC model. Therefore, the GSH-disrupting GDNS represents an encouraging strategy to potentiate ferroptosis for treating refractory LAR-subtype TNBC.

Lactobacilli Cell-Free Supernatants Modulate Inflammation and Oxidative Stress in Human Microglia via NRF2-SOD1 Signaling

Microglia are macrophage cells residing in the brain, where they exert a key role in neuronal protection. Through the gut–brain axis, metabolites produced by gut commensal microbes can influence brain functions, including microglial activity. The nuclear factor erythroid 2-related factor 2 (NRF2) is a key regulator of the oxidative stress response in microglia, controlling the expression of cytoprotective genes. Lactobacilli-derived cell-free supernatants (CFSs) are postbiotics that have shown antioxidant and immunomodulatory effects in several in vitro and in vivo studies. This study aimed to explore the effects of lactobacilli CFSs on modulating microglial responses against oxidative stress and inflammation. HMC3 microglia were exposed to lipopolysaccaride (LPS), as an inflammatory trigger, before and after administration of CFSs from three human gut probiotic species. The NRF2 nuclear protein activation and the expression of NRF2-controlled antioxidant genes were investigated by immunoassay and quantitative RT-PCR, respectively. Furthermore, the level of pro- and anti-inflammatory cytokines was evaluated by immunoassay. All CFSs induced a significant increase of NRF2 nuclear activity in basal conditions and upon inflammation. The transcription of antioxidant genes, namely heme oxygenase 1, superoxide dismutase (SOD), glutathione-S transferase, glutathione peroxidase, and catalase also increased, especially after inflammatory stimulus. Besides, higher SOD1 activity was detected relative to inflamed microglia. In addition, CFSs pre-treatment of microglia attenuated pro-inflammatory TNF-α levels while increasing anti-inflammatory IL-10 levels. These findings confirmed that gut microorganisms’ metabolites can play a relevant role in adjuvating the microglia cellular response against neuroinflammation and oxidative stress, which are known to cause neurodegenerative diseases.Graphical Gut-brain crosstalk: molecular point of view. Metabolites contained in the supernatant derived from Lactobacilli can cross the gut barrier and reach the central nervous system, where they are taken up by microglial cells. They induce the activation of the NRF2 pathway and the production of inflammatory mediators. This interaction attenuates two important events: oxidation (with high levels of NRF2) and inflammation (with high levels of IL-10 and low levels of TNF-α).

Selenium alleviates dextran sulfate sodium-induced colitis and inhibits ferroptosis of intestinal epithelial cells via upregulating glutathione peroxidase 4.

Selenium, an essential micronutrient for humans, has been shown to be protective against ulcerative colitis (UC), but the exact mechanism remains unclear. The role of selenium, protecting against ferroptosis of intestinal epithelial cells (IECs) in colitis, was investigated in this current study. Serum selenium level and ferroptosis-related gene expression in the colonic mucosa were measured in UC patients and healthy controls. The effects of sodium selenite supplementation on experimental colitis were investigated in dextran sulfate sodium (DSS)-treated mice. The influence of sodium selenite on IEC ferroptosis was evaluated through assessing cell death rate, intracellular ferrous iron content, lipid reactive oxygen species level, and mitochondrial membrane damage of DSS-treated Caco-2 cells. Moreover, glutathione peroxidase 4 (GPX4) and acyl-CoA synthetase long-chain family member 4, ferroptosis-related genes, were detected in Caco-2 cells and mouse intestines. Serum selenium was decreased in UC patients in comparison with healthy individuals. Additionally, serum selenium level was negatively correlated with disease activity and was associated with clinical inflammation and nutrition indicators. The expression of GPX4 in the mucosa of UC was positively correlated with serum selenium level. The in vivo experiments showed that selenium treatment ameliorated DSS-induced colitis and inhibited ferroptosis in IECs. The in vitro results suggested that selenium supplementation inhibited DSS-induced ferroptosis in Caco-2 cells. GPX4 was upregulated after selenium supplementation both in vivo and in vitro. Serum selenium level was associated with IEC ferroptosis in UC patients. Selenium supplementation alleviates DSS-induced colitis and inhibits ferroptosis in IECs by upregulating the expression of GPX4.