Critical Roles of the Cysteine-Glutathione Axis in the Production of γ-Glutamyl Peptides in the Nervous System.

γ-Glutamyl moiety that is attached to the cysteine (Cys) residue in glutathione (GSH) protects it from peptidase-mediated degradation. The sulfhydryl group of the Cys residue represents most of the functions of GSH, which include electron donation to peroxidases, protection of reactive sulfhydryl in proteins via glutaredoxin, and glutathione conjugation of xenobiotics, whereas Cys-derived sulfur is also a pivotal component of some redox-responsive molecules. The amount of Cys that is available tends to restrict the capacity of GSH synthesis. In in vitro systems, cystine is the major form in the extracellular milieu, and a specific cystine transporter, xCT, is essential for survival in most lines of cells and in many primary cultivated cells as well. A reduction in the supply of Cys causes GPX4 to be inhibited due to insufficient GSH synthesis, which leads to iron-dependent necrotic cell death, ferroptosis. Cells generally cannot take up GSH without the removal of γ-glutamyl moiety by γ-glutamyl transferase (GGT) on the cell surface. Meanwhile, the Cys-GSH axis is essentially common to certain types of cells; primarily, neuronal cells that contain a unique metabolic system for intercellular communication concerning γ-glutamyl peptides. After a general description of metabolic processes concerning the Cys-GSH axis, we provide an overview and discuss the significance of GSH-related compounds in the nervous system.

WIPI2 enhances the vulnerability of colorectal cancer cells to erastin via bioinformatics analysis and experimental verification.

Introduction: WD Repeat Domain Phosphoinositide Interacting 2 (WIPI2) is a WD repeat protein that interacts with phosphatidylinositol and regulates multiprotein complexes by providing a b-propeller platform for synchronous and reversible protein-protein interactions assembled proteins. Ferroptosis is a novel iron-dependent form of cell death. It is usually accompanied with the accumulation of membrane lipid peroxides. Our study is to focus on investigating the effect of WIPI2 on the growth and ferroptosis of colorectal cancer (CRC) cells and its potential mechanism. Methods: We analyzed the expression of WIPI2 in colorectal cancer versus normal tissues through The Cancer Genome Atlas (TCGA), and the relationship between clinical traits and WIPI2 expression and prognosis was assessed by univariate and multifactorial cox analysis. Next, we constructed the siRNAs targeting the WIPI2 sequence si-WIPI2 to further investigate the mechanism of WIPI2 in CRC cells through vitro experiments. Results: Public data from the TCGA platform showed that WIPI2 expression was significantly elevated in colorectal cancer tissues compared to paracancerous tissues, and high WIPI2 expressionpredicted poor prognosis for CRC patients. Moreover, we found that the knockdown of WIPI2 expression could inhibit the growth and proliferation of HCT116 and HT29 cells. Furthermore, we found that the expression level of ACSL4 decreased and that of GPX4 increased when WIPI2 was knocked down, suggesting that WIPI2 can potentially positively regulate CRC ferroptosis. Meanwhile, both NC and si groups were able to further inhibit cell growth activity, as well as increase WIPI2 and decrease GPX4 expression when treated with Erastin, but the rate of cell viability inhibition and the trend of protein changes were more significantly in the NC group than si groups, which indicated that Erastin induced CRC ferroptosis through the WIPI2/GPX4 pathway thereby enhancing the sensitivity of colorectal cancer cells to Erastin. Conclusions: Our study suggested that WIPI2 had a promotional effect on the growth of colorectal cancer cells, and it also played an important role in the ferroptosis pathway.

In vivo antioxidant activity of rabbiteye blueberry (Vaccinium ashei cv. 'Brightwell') anthocyanin extracts. / '灿烂'å“ç§å ”çœ¼è“èŽ“èŠ±é’ç´ æå–ç‰©åœ¨ä½“å† çš„æŠ—æ°§åŒ–æ´»æ€§.

Blueberries are rich in phenolic compounds including anthocyanins which are closely related to biological health functions. The purpose of this study was to investigate the antioxidant activity of blueberry anthocyanins extracted from 'Brightwell' rabbiteye blueberries in mice. After one week of adaptation, C57BL/6J healthy male mice were divided into different groups that were administered with 100, 400, or 800 mg/kg blueberry anthocyanin extract (BAE), and sacrificed at different time points (0.1, 0.5, 1, 2, 4, 8, or 12 h). The plasma, eyeball, intestine, liver, and adipose tissues were collected to compare their antioxidant activity, including total antioxidant capacity (T-AOC), superoxide dismutase (SOD) activity and glutathione-peroxidase (GSH-PX/GPX) content, and the oxidative stress marker malondialdehyde (MDA) level. The results showed that blueberry anthocyanins had positive concentration-dependent antioxidant activity in vivo. The greater the concentration of BAE, the higher the T-AOC value, but the lower the MDA level. The enzyme activity of SOD, the content of GSH-PX, and messenger RNA (mRNA) levels of Cu,Zn-SOD, Mn-SOD, and GPX all confirmed that BAE played an antioxidant role after digestion in mice by improving their antioxidant defense. The in vivo antioxidant activity of BAE indicated that blueberry anthocyanins could be developed into functional foods or nutraceuticals with the aim of preventing or treating oxidative stress-related diseases.

Relevance of oxidative stress biomarkers, hemoglobin A1c, troponin-I, and angiotensin-converting enzyme metabolism to blood pressure in acute myocardial infarction: a case-control study.

The aim was to investigate this relationship by calculating 1) the correlation between peak troponin-C (peak-cTnI), levels of oxidative stress biomarkers, including lipid peroxidation products (malondialdehyde (MDA), conjugated dienes (CD)), and antioxidant enzyme activity (glutathione peroxidase (GPx)), and HbA1c and 2) the correlation between HbA1c and serum angiotensin-converting enzyme (ACE) activity, and its impact on the rate pressure product (RPP) in acute myocardial infarction (AMI). A case-control study was performed in 306 AMI patients having undergone coronary angiography and on 410 controls. GPx activity was reduced in association with increased MDA and CD in patients. Peak-cTnI was positively correlated with HbA1c, MDA, and CD levels. Serum ACE activity was negatively correlated with GPx. HbA1c was positively correlated with ACE activity and RPP. Linear regression analysis showed that peak-cTnI, ACE activity and HbA1c are significant predictors of AMI. Elevated HbA1c and peak-cTnI levels are associated with RPP elevation causing AMI. In conclusions, patients with elevated HbA1c, elevated ACE activity and cTnI are at increased risk of AMI with increasing RPP. Patients at risk of AMI can be identified at an early stage if the biomarkers HbA1c, ACE activity, and cTnI are measured and preventive measures are taken in a targeted manner.

Lysine malonylation of DgnsLIPID TRANSFER PROTEIN1 at the K81 site improves cold resistance in chrysanthemum.

Lysine malonylation (Kmal) is a recently discovered post-translational modification, and its role in the response to abiotic stress has not been reported in plants. In this study, we isolated a non-specific lipid transfer protein, DgnsLTP1, from chrysanthemum (Dendranthema grandiflorum var. Jinba). Overexpression and CRISPR-Cas9-mediated gene editing of DgnsLTP1 demonstrated that the protein endows chrysanthemum with cold tolerance. Yeast two-hybrid (Y2H), bimolecular fluorescence complementation (BiFC), luciferase complementation imaging (LCI) and co-immunoprecipitation (Co-IP) experimental results showed that DgnsLTP1 interacts with a plasma membrane intrinsic protein DgPIP (plasma membrane intrinsic protein). Overexpressing DgPIP boosted the expression of DgGPX (Glutathione peroxidase), increased the activity of GPX, and decreased the accumulation of reactive oxygen species (ROS), thereby enhancing the low-temperature stress tolerance of chrysanthemum, while the CRISPR-Cas9-mediated mutant dgpip inhibited this process. Transgenic analyses in chrysanthemum showed that DgnsLTP1 improves the cold resistance of chrysanthemum in a DgPIP-dependent manner. Moreover, lysine malonylation of DgnsLTP1 at the K81 site prevented the degradation of DgPIP in Nicotiana benthamiana and chrysanthemum, further promoted DgGPX expression, enhanced GPX activity, and scavenged excess ROS produced by cold stress, thereby further enhancing the cold resistance of chrysanthemum.

Dataset on the proteomic response during ferroptosis induction via tamoxifen induced GPX4 KO in mouse embryonic fibroblasts.

Ferroptosis is a type of programmed cell death distinct from apoptosis and necroptosis that plays an essential role in pathophysiological conditions such as neurodegenerative diseases and tumorigenesis. Massive lipid oxidation in an iron-dependent manner is a hallmark of ferroptosis.This modality of cell death is also characterized by perturbation of several metabolic pathways, predominantly fatty acid metabolism, thiol metabolism, iron homeostasis and the mevalonate pathway. We aimed to acquire data from different timepoints of ferroptotic death in order to get information about the primary and delayed phases of the ferroptotic response. For this purpose, we used model Pfa1 cells, which are 4-OH-TAM-inducible Gpx4-/- mouse immortalized fibroblasts [1]. GPX4 is one of the main intracellular ferroptosis regulators and inhibiting it is a classic approach to induce ferroptosis. Measuring protein fold changes at different ferroptotic stages and in nontreated Pfa1 cells could give useful information on the activation of genes involved in ferroptosis and non-genomic protein regulation during ferroptotic progression. Bottom-up proteomic data were acquired from samples obtained 24 and 48 hours after genetic induction of ferroptosis. Chromato-mass spectra were registered in DDA mode and are suitable for further label-free quantification. These data might be a valuable proteome basis for further investigation of ferroptosis and complement other available omics.

Naringenin Prevents Renal Injury in Experimental Hyperuricemia Through Suppressing Xanthine Oxidase, Inflammation, Apoptotic Pathway, DNA Damage, and Activating Antioxidant System.

Background/Purpose: This research was performed to determine the effect of naringenin (NAR) in experimental hyperuricemia (HU) induced by potassium oxonate (PO) on uric acid levels and xanthine oxidase (XO), inflammation, apoptotic pathway, DNA damage, and antioxidant system in kidney tissue. Study Design: Wistar Albino rats were categorized into four groups: (1) Control group, (2) PO group, (3) [PO+NAR] (2 weeks) group, and (4) PO (2 weeks)+NAR (2 weeks) group. Methods: The first group was not administered any drug. In group 2, PO was administered intraperitoneally 250 mg/kg/day for 2 weeks. In the third group, 100 mg/kg/day NAR was given intraperitoneally 1 hr after PO injection for 2 weeks. In the fourth group, PO was injected for the first 2 weeks, followed by NAR injection for the second 2 weeks. Serum uric acid levels, XO, nuclear factor-kappa B, tumor necrosis factor-alpha, interleukin-17, cytochrome c, 8-Hydroxydeoxyguanosine (8-OHdG), glutathione peroxidase (GPx), and caspase-3 levels in kidney were determined. Results: HU increased the levels of inflammatory and apoptotic parameters, XO, and 8-OHdG levels in kidney. Administration of NAR caused a decrease in these values and an increase in GPx levels. Conclusions: The results of the study show that NAR treatment reduces serum uric acid levels, and apoptosis, inflammation, and DNA damage; increases antioxidant activity in kidney in experimental HU.

Ultrasound-Targeted Microbubble Disruption with Key Nanodroplets for Effective Ferroptosis in Triple-Negative Breast Cancer Using Animal Model.

Introduction: Triple-negative breast cancer (TNBC) is known to be the most aggressive form of breast cancer. Due to its high recurrence and mortality rates, the treatment of TNBC is a significant challenge for the medical community. Besides, ferroptosis is an emerging regulatory cell death that may provide new insights into the treatment of TNBC. As a central inhibitor of the ferroptosis process, the selenoenzyme glutathione peroxidase 4 (GPX4) is its classical therapeutic target. However, inhibition of GPX4 expression is quite detrimental to normal tissues. Ultrasound contrast agents, as an emerging visualization precision treatment, may provide a solution to the existing problem. Methods: In this study, nanodroplets (NDs) carrying simvastatin (SIM) were constructed using the homogeneous/emulsification method. Then, the characterization of SIM-NDs was systematically evaluated. Meanwhile, in this study, the ability of SIM-NDs combined with ultrasound-targeted microbubble disruption (UTMD) to initiate ferroptosis and its respective mechanisms of ferroptosis induction were verified. Finally, the antitumor activity of SIM-NDs was investigated in vitro and in vivo using MDA-MB-231 cells and TNBC animal models. Results: SIM-NDs exhibited excellent pH- and ultrasound-responsive drug release and noticeable ultrasonographic imaging ability, also showing good biocompatibility and biosafety. UTMD could promote increased intracellular reactive oxygen species and consume intracellular glutathione. However, SIM-NDs were efficiently internalized into cells under ultrasound irradiation, followed by the rapid release of SIM, which inhibited intracellular mevalonate production, and synergistically downregulated GPX4 expression, thereby promoting ferroptosis. Moreover, this combined treatment demonstrated strong antitumor ability in vitro and in vivo. Conclusion: The combination of UTMD and SIM-NDs presents a promising avenue for harnessing ferroptosis in the treatment of malignant tumors.

Liquiritin reduces ferroptosis in doxorubicin-induced cardiotoxicity through targeting SLC7A11/GPX4 pathway.

Solute carrier family 7 member (SLC7A11) and glutathione peroxidase 4 (GPX4) mediated ferroptosis in doxorubicin-induced cardiotoxicity. Based on the bioinformatics analysis, liquiritin, a flavonoid isolated from the rhizome part of Glycyrrhiza glabra with activities of anti-inflammatory and anti-oxidant, is forecasted to synchronously with ferroptosis-relevant protein. This study aims to investigate the effect of liquiritin on doxorubicin-induced cardiotoxicity and the underlying mechanisms. The C57BL/6 J mice heart or cardiomyocytes were subjected to doxorubicin in vivo or in vitro, which were treated with liquiritin at different dosages. The heart or H9c2 cell cardiotoxicity, relevant protein levels, and ferroptosis were measured by methods of biochemistry, flow cytometry, or Western blot. The mice treated with doxorubicin showed evident cardiotoxicity, concomitant with the downregulation of SLC7A11 and GPX4, and accelerate ferroptosis. Administration of liquiritin could relieve the heart injury, accompanied by restoration of the levels of SLC7A11 and GPX4, and inhibit ferroptosis. And liquiritin ameliorated similar effects in doxorubicin-treated H9c2 cells. Based on these findings, we conclude that liquiritin can protect the doxorubicin-induce mice's cardiotoxicity, and its beneficial effect is related to the reduction of ferroptosis through a mechanism involving the regulation of the SLC7A11/GPX4 pathway.

Measures of Oxidative Status Markers in Relation to Age, Sex, and Season in Sick and Healthy Captive Asian Elephants in Thailand.

Oxidative stress is a pathological condition that can have adverse effects on animal health, although little research has been conducted on wildlife species. In this study, blood was collected from captive Asian elephants for the assessment of five serum oxidative status markers (reactive oxygen species (ROS) concentrations; malondialdehyde, MDA; albumin; glutathione peroxidase, GPx; and catalase) in healthy (n = 137) and sick (n = 20) animals. Health problems consisted of weakness, puncture wounds, gastrointestinal distress, eye and musculoskeletal problems, and elephant endotheliotropic herpesvirus hemorrhagic disease (EEHV-HD). Fecal samples were also collected to assess glucocorticoid metabolites (fGCMs) as a measure of stress. All data were analyzed in relation to age, sex, sampling season, and their interactions using generalized linear models, and a correlation matrix was constructed. ROS and serum albumin concentrations exhibited the highest concentrations in aged elephants (>45 years). No sex differences were found for any biomarker. Interactions were observed for age groups and seasons for ROS and catalase, while GPx displayed a significant interaction between sex and season. In pairwise comparisons, significant increases in ROS and catalase were observed in summer, with higher ROS concentrations observed only in the adult female group. Lower catalase activity was exhibited in juvenile males, subadult males, adult females, and aged females compared to subadult and adult elephants (males and females) in winter and the rainy season. There was a positive association between catalase activity and fGCMs (r = 0.23, p < 0.05), and a number of red blood cell parameters were positively associated with several of these biomarkers, suggesting high oxidative and antioxidative activity covary in red cells (p < 0.05). According to health status, elephants with EEHV-HD showed the most significant changes in oxidative stress markers, with MDA, GPx, and catalase being higher and albumin being lower than in healthy elephants. This study provides an analysis of understudied health biomarkers in Asian elephants, which can be used as additional tools for assessing the health condition of this species and suggests age and season may be important factors in data interpretation.

Role of ferroptosis in the pathogenesis and as a therapeutic target of inflammatory bowel disease (Review).

Ferroptosis, a novel form of regulated cell death, is characterized by the accumulation of labile iron and lipid peroxidation, and the excessive production of reactive oxygen species (ROS). Although ferroptosis lies at the center of crucial biological activities involving O2, iron and polyunsaturated fatty acids (PUFAs), which are essential for cell proliferation and growth, the interaction between these molecules could also mediate the accumulation of toxic levels of ROS and lipid peroxides, which can then cause damage to cellular membranes and ultimately result in cell death. Recent reports have indicated that ferroptosis participates in the development and progression of inflammatory bowel disease (IBD), offering a new exploratory field which may aid in the more in­depth understanding of the pathogenesis and therapeutic targets of IBD. Of note, the mitigation of the characteristic features of ferroptosis, such as depleted glutathione (GSH) levels, inactivated glutathione peroxidase 4 (GPX4), elevated levels of lipid peroxidation and iron overload significantly relieve IBD. This has attracted the attention of researches aiming to examine therapeutic agents that inhibit ferroptosis in IBD, including radical­trapping antioxidants, enzyme inhibitors, iron chelators, protein degradation inhibitors, stem cell­derived exosomes and oral N­acetylcysteine or glutathione. The present review summarizes and discusses the current data that implicate ferroptosis in the pathogenesis of IBD and its inhibition as a novel alternate therapeutic target for IBD. The mechanisms and key mediators of ferroptosis, including GSH/GPX4, PUFAs, iron and organic peroxides are also discussed. Although the field is relatively new, the therapeutic regulation of ferroptosis has exhibited promising outcomes as a novel treatment avenue for IBD.

GPX8 deficiency-induced oxidative stress reprogrammed m6A epitranscriptome of oral cancer cells.

Glutathione peroxidase 8 (GPX8) is a key regulator of redox homoeostasis. Whether its antioxidant activity participates in the regulation of m6A modification is a crucial issue, which has important application value in cancer treatment. In this study, MeRIP-seq was used to explore the characteristics of transcriptome-wide m6A modification in GPX8-deficient oral cancer cells. Oxidative stress caused by the lack of GPX8 resulted in 1,279 hyper- and 2,287 hypo-methylated m6A peaks and 2,036 differentially expressed genes in GPX8-KO cells. Twenty-eight differentially expressed genes were related to the cell response to oxidative stress, and half of them changed their m6A modification. In GPX8-KO cells, m6A regulators IGF2BP2 and IGF2BP3 were upregulated, while FTO, RBM15, VIRMA, ZC3H13, and YTHDC2 were downregulated. After H2O2 treatment, the expression changes of RBM15, IGF2BP2, and IGF2BP3 were further enhanced. These data indicated that GPX8-mediated redox homoeostasis regulated m6A modification, thereby affecting the expression and function of downstream genes. This study highlights the possible significance of GPX8 and the corresponding m6A regulatory or regulated genes as novel targets for antioxidant intervention in cancer therapy.

Lack of GPX8 caused oxidative stress of oral cancer cells.Oxidative stress induced by GPX8 deficiency reprogrammed m⁶A epitranscriptome.GPX8 deletion­caused oxidative stress regulated expression of m⁶A regulatory genes.m⁶A modification of antioxidant genes is the adaptive response of cells to oxidative stress.

Exploiting Cancer Vulnerabilities by Blocking of the DHODH and GPX4 Pathways: A Multifunctional Bodipy/PROTAC Nanoplatform for the Efficient Synergistic Ferroptosis Therapy.

Ferroptosis is a form of programmed cell death and plays an important role in many diseases. Dihydroorotate dehydrogenase (DHODH) and glutathione peroxidase 4 (GPX4) play major roles in cell resistance to ferroptosis. Therefore, inactivation of these proteins provides an excellent opportunity for efficient ferroptosis-based synergistic cancer therapy. In this study, a multifunctional nanoagent (BPNpro ) containing a GPX4 targeting boron dipyrromethene (Bodipy) probe (BP) and a DHODH targeting proteolysis targeting chimera (PROTAC) is reported. BPNpro is prepared using a nanoprecipitation method in the presence of a thermoresponsive liposome, where BP is encapsulated inside and the cathepsin B (CatB)-cleavable PROTAC peptide (DPCP) is modified on the outer surface. In the presence of near-infrared (NIR) photoirradiation, BPNpro is melted and BP is released in tumor cells. Subsequently, BP inhibits the activity of GPX4 by covalently bonding with the selenocysteine at the enzyme active site. In addition, DPCP achieves sustained degradation of DHODH upon activation by CatB overexpressed in the tumor. The synergistic deactivation of GPX4 and DHODH induces extensive ferroptosis and subsequent cell death. In vivo and in vitro studies clearly show that the proposed ferroptosis therapy provides excellent antitumor effect.

Ferroptosis: mechanisms and implications for cancer development and therapy response.

As cancer cells develop resistance to apoptosis, non-apoptotic cell death modalities, such as ferroptosis, have emerged as promising strategies to combat therapy-resistant cancers. Cells that develop resistance to conventional therapies or metastatic cancer cells have been shown to have increased sensitivity to ferroptosis. Therefore, targeting the regulatory elements of ferroptosis in cancer could offer novel therapeutic opportunities. In this review, we first provide an overview of the known ferroptosis regulatory networks and discuss recent findings on how they contribute to cancer plasticity. We then expand into the critical role of selenium metabolism in regulating ferroptosis. Finally, we highlight specific cases where induction of ferroptosis could be used to sensitize cancer cells to this form of cell death.

Antioxidant Role in Critically Ill Patients with Vasodilatory Shock: Does Glutathione Peroxidase Correlate to Severity of Tissue Hypoxia and Organ Failure.

Purpose: We aimed to evaluate the antioxidant role in critically ill patients with vasodilatory shock as it relates to severity of tissue hypoxia and organ failure. Patients and Methods: An observational and prospective study was conducted in critically ill patients with vasodilatory shock. Glutathione peroxidase (GPx) levels as antioxidants were measured based on their levels in the patient's serum. Tissue hypoxia as micro-hemodynamic status was represented by lactate levels, the macro-hemodynamic status was represented by vasoactive inotropic score (VIS) and mean arterial pressure (MAP), while organ dysfunction severity was represented by the shock index (SI), the sequential organ failure assessment (SOFA) score, and the acute physiology and chronic health evaluation (APACHE) II score. Results: Thirty-four critically ill patients with vasodilatory shock met the eligibility criteria. The mortality rate was 41.2%. Glutathione peroxidase levels did not show a significant difference between survivors and non-survivors at baseline or after 24 hours. At the initial measurement, there was a correlation between GPx and lactate levels, GPx and SOFA scores. The macrohemodynamic status was represented by VIS and MAP, which were correlated with SI. Conclusion: Glutathione peroxidase as antioxidant is related to severity of tissue hypoxia and organ failure in critically ill patients with vasodilatory shock.

Antioxidant Nanozymes: Mechanisms, Activity Manipulation, and Applications.

Antioxidant enzymes such as catalase, superoxide dismutase, and glutathione peroxidase play important roles in the inhibition of oxidative-damage-related pathological diseases. However, natural antioxidant enzymes face some limitations, including low stability, high cost, and less flexibility. Recently, antioxidant nanozymes have emerged as promising materials to replace natural antioxidant enzymes for their stability, cost savings, and flexible design. The present review firstly discusses the mechanisms of antioxidant nanozymes, focusing on catalase-, superoxide dismutase-, and glutathione peroxidase-like activities. Then, we summarize the main strategies for the manipulation of antioxidant nanozymes based on their size, morphology, composition, surface modification, and modification with a metal-organic framework. Furthermore, the applications of antioxidant nanozymes in medicine and healthcare are also discussed as potential biological applications. In brief, this review provides useful information for the further development of antioxidant nanozymes, offering opportunities to improve current limitations and expand the application of antioxidant nanozymes.

Effects of Taraxerol on Oxidative and Inflammatory Mediators in Isoproterenol-Induced Cardiotoxicity in an Animal Model.

Myocardial infarction (MI) continues to be an important issue in healthcare systems worldwide, leading to high rates of morbidity and mortality. Despite ongoing efforts towards the development of preventive measures and treatments, addressing the challenges posed by MI remains difficult both in developed and developing countries. However, researchers recently investigated the potential cardioprotective effects of taraxerol utilizing an isoproterenol (ISO)-induced cardiotoxicity model among Sprague Dawley rats. Specifically, subcutaneous tissue injections consisting of 5.25 mg/kg or 8.5 mg/kg ISO were administered over two consecutive days as stimuli to induce cardiac injury. To investigate the possibility of preventing damage caused by ISO-induced cardiotoxicity by taraxerol treatment, five groups were formed: a normal control group (1% Tween 80), an ISO control group, an amlodipine group administered 5 mg/kg/day, and various doses of taraxerol. The study results showed that treatment significantly reduced cardiac marker enzymes. Additionally, pretreatment with taraxerol increased myocardial activity in SOD and GPx, leading to significant reductions in serum CK-MB levels along with MDA, TNF-α, and IL-6. Further histopathological analysis supported these observations, as treated animals had less cellular infiltration compared to untreated ones. These multifaceted findings suggest that oral administration of taraxerol could potentially protect hearts from ISO-caused damage by increasing endogenous antioxidant concentrations while decreasing pro-inflammatory cytokines.

Development of an assay pipeline for the discovery of novel small molecule inhibitors of human glutathione peroxidases GPX1 and GPX4.

Selenoprotein glutathione peroxidases (GPX), like ubiquitously expressed GPX1 and the ferroptosis modulator GPX4, enact antioxidant activities by reducing hydroperoxides using glutathione. Overexpression of these enzymes is common in cancer and can be associated with the development of resistance to chemotherapy. GPX1 and GPX4 inhibitors have thus shown promise as anti-cancer agents, and targeting other GPX isoforms may prove equally beneficial. Existing inhibitors are often promiscuous, or modulate GPXs only indirectly, so novel direct inhibitors identified through screening against GPX1 and GPX4 could be valuable. Here, we developed optimized glutathione reductase (GR)-coupled GPX assays for the biochemical high-throughput screen (HTS) of almost 12,000 compounds with proposed mechanisms of action. Initial hits were triaged using a GR counter-screen, assessed for isoform specificity against an additional GPX isoform, GPX2, and were assessed for general selenocysteine-targeting activity using a thioredoxin reductase (TXNRD1) assay. Importantly, 70% of the GPX1 inhibitors identified in the primary screen, including several cephalosporin antibiotics, were found to also inhibit TXNRD1, while auranofin, previously known as a TXNRD1 inhibitor, also inhibited GPX1 (but not GPX4). Additionally, every GPX1 inhibitor identified (including omapatrilat, tenatoprazole, cefoxitin and ceftibuten) showed similar inhibitory activity against GPX2. Some compounds inhibiting GPX4 but not GPX1 or GPX2, also inhibited TXNRD1 (26%). Compounds only inhibiting GPX4 included pranlukast sodium hydrate, lusutrombopag, brilanestrant, simeprevir, grazoprevir (MK-5172), paritaprevir, navitoclax, venetoclax and VU0661013. Two compounds (metamizole sodium and isoniazid sodium methanesulfate) inhibited all three GPXs but not TXNRD1, while 2,3-dimercaptopropanesulfonate, PI4KIII beta inhibitor 3, SCE-2174 and cefotetan sodium inhibited all tested selenoproteins (but not GR). The detected overlaps in chemical space suggest that the counter screens introduced here should be imperative for identification of specific GPX inhibitors. With this approach, we could indeed identify novel GPX1/GPX2- or GPX4-specific inhibitors, thus presenting a validated pipeline for future identification of specific selenoprotein-targeting agents. Our study also identified GPX1/GPX2, GPX4 and/or TXNRD1 as targets for several previously developed pharmacologically active compounds.

The contribution of glutathione peroxidases to chloroplast redox homeostasis in Arabidopsis.

Oxidizing signals mediated by the thiol-dependent peroxidase activity of 2-Cys peroxiredoxins (PRXs) plays an essential role in fine-tuning chloroplast redox balance in response to changes in light intensity, a function that depends on NADPH-dependent thioredoxin reductase C (NTRC). In addition, plant chloroplasts are equipped with glutathione peroxidases (GPXs), thiol-dependent peroxidases that rely on thioredoxins (TRXs). Despite having a similar reaction mechanism than 2-Cys PRXs, the contribution of oxidizing signals mediated by GPXs to the chloroplast redox homeostasis remains poorly known. To address this issue, we have generated the Arabidopsis (Arabidopsis thaliana) double mutant gpx1gpx7, which is devoid of the two GPXs, 1 and 7, localized in the chloroplast. Furthermore, to analyze the functional relationship of chloroplast GPXs with the NTRC-2-Cys PRXs redox system, the 2cpab-gpx1gpx7 and ntrc-gpx1gpx7 mutants were generated. The gpx1gpx7 mutant displayed wild type-like phenotype indicating that chloroplast GPXs are dispensable for plant growth at least under standard conditions. However, the 2cpab-gpx1gpx7 showed more retarded growth than the 2cpab mutant. The simultaneous lack of 2-Cys PRXs and GPXs affected PSII performance and caused higher delay of enzyme oxidation in the dark. In contrast, the ntrc-gpx1gpx7 mutant combining the lack of NTRC and chloroplast GPXs behaved like the ntrc mutant indicating that the contribution of GPXs to chloroplast redox homeostasis is independent of NTRC. Further supporting this notion, in vitro assays showed that GPXs are not reduced by NTRC but by TRX y2. Based on these results, we propose a role for GPXs in the chloroplast redox hierarchy.

Application of an Integrative Drug Safety Model for Detection of Adverse Drug Events Associated With Inhibition of Glutathione Peroxidase 1 in Chronic Obstructive Pulmonary Disease.

BACKGROUND: Chronic Obstructive Pulmonary Disease is characterised by declining lung function and a greater oxidative stress burden due to reduced activity of antioxidant enzymes such as Glutathione Peroxidase 1. OBJECTIVES: The extent to which drugs may contribute to this compromised activity is largely unknown. An integrative drug safety model explores inhibition of Glutathione Peroxidase 1 by drugs and their association with chronic obstructive pulmonary disease adverse drug events. METHODS: In silico molecular modelling approaches were utilised to predict the interactions that drugs have within the active site of Glutathione Peroxidase 1 in both human and bovine models. Similarities of chemical features between approved drugs and the known inhibitor tiopronin were also investigated. Subsequently the Food and Drug Administration Adverse Event System was searched to uncover adverse drug event signals associated with chronic obstructive pulmonary disease. RESULTS: Statistical and molecular modelling analyses confirmed that the use of several registered drugs, including acetylsalicylic acid and atenolol may be associated with inhibition of Glutathione Peroxidase 1 and chronic obstructive pulmonary disease. CONCLUSION: The integration of molecular modelling and pharmacoepidemological data has the potential to advance drug safety science. Ongoing review of medication use and further pharmacoepidemiological and biological analyses are warranted to ensure appropriate use is recommended.