Expression Of Glutathione Peroxidase Research Articles

Dietary honokiol supplementation improves antioxidant capacity, enhances intestinal health, and modulates cecal microbial composition and function of broiler chickens

Honokiol is a multifunctional polyphenol present in Magnolia officinalis. The effects of honokiol as a supplement in broiler chicken diets, and the underlying mechanisms, remain unclear. Therefore, the aim of the present study was to investigate the effects of honokiol on the growth performance, antioxidant capacity, and intestinal histomorphology of broiler chickens and to explore the underlying mechanisms. In total, 240 one-day-old broilers were randomly allocated to 5 dietary treatments, with 6 replicate pens and 8 birds per pen. Birds were fed a basal diet supplemented with 0 (blank control, BC), 100, 200, or 400 mg/kg honokiol (H100, H200, and H400), or 200 mg/kg bacitracin zinc (PC) for 42 d. The results showed that H200 and H400 increased body weight gain (BWG) and decreased feed conversion ratio (FCR) during the starter period (P < 0.05). H100 and H200 increased total superoxide dismutase (T-SOD) activity in the serum and decreased malondialdehyde (MDA) amount in the jejunum on d 42 (P < 0.05). Moreover, H100 increased villus height-to-crypt depth ratio in both the jejunum and ileum on d 21 (P < 0.05). PCR analysis showed that honokiol upregulated intestinal expression of glutathione peroxidase (GSH-Px) and downregulated intestinal expression of inducible nitric oxide synthase (iNOS) on d 42 (P < 0.05). The Shannon index, which represents the microbial alpha diversity, was reduced for the PC, H200, and H400 groups. Notably, honokiol treatment altered the cecal microbial community structure and promoted the enrichment of several bacteria, including Firmicutes and Lactobacillus. Higher production of short-chain fatty acids was observed in the cecal digesta of H100 birds, accompanied by an enriched glycolysis/gluconeogenesis pathway, according to the functional prediction of the cecal microbiota. This study provides evidence that honokiol improves growth performance, antioxidant capacity, and intestinal health of broiler chickens, possibly by manipulating the composition and function of the microbial community.

Ferroptosis resists intracellular Vibrio splendidus AJ01 mediated by ferroportin in sea cucumber Apostichopus japonicus

Ferroptosis, a kind of programmed cell death, is characterized with iron-dependent lipid ROS buildup, which is considered as an important cellular immunity in resisting intracellular bacterial infection in mammalian macrophages. In this process, lipid ROS oxidizes the bacterial biofilm to inhibit intracellular bacteria. However, the function of ferroptosis in invertebrate remains unknown. In this study, the existence of ferroptosis in Apostichopus japonicus coelomocytes was confirmed, and its antibacterial mechanism was investigated. First, our results indicated that the expression of glutathione peroxidase (AjGPX4) was significantly inhibited by 0.21-fold (p < 0.01) after injecting A. japonicus with the ferroptosis inducer RSL3, and the contents of MDA (3.93-fold, p < 0.01), ferrous iron (1.40-fold, p < 0.01), and lipid ROS (3.10-fold, p < 0.01) were all significantly increased under this condition and simultaneously accompanied with mitochondrial contraction and disappearance of cristae, indicating the existence of ferroptosis in the coelomocytes of A. japonicus. Subsequently, the contents of ferrous iron (1.40-fold, p < 0.05), MDA (2.10-fold, p < 0.01), ROS (1.70-fold, p < 0.01), and lipid ROS (2.50-fold, p < 0.01) were all significantly increased, whereas the mitochondrial membrane potential and GSH/GSSG were markedly decreased by 0.68-fold (p < 0.05) and 0.69-fold (p < 0.01) under Vibrio splendidus (AJ01) infection. This process could be reversed by the iron-chelating agent deferoxamine mesylate, which indicated that AJ01 could induce coelomocytic ferroptosis. Moreover, the results demonstrated that the intracellular AJ01 load was clearly decreased to 0.49-fold (p < 0.05) and 0.06-fold (p < 0.01) after treating coelomocytes with RSL3 and ferrous iron, which indicated that enhanced ferroptosis could inhibit bacterial growth. Finally, subcellular localization demonstrated that ferrous iron efflux protein ferroportin (AjFPN) and intracellular AJ01 were co-localized in coelomocytes. After AjFPN interference (0.58-fold, p < 0.01), the signals of ferrous iron and lipid ROS levels in intracellular AJ01 were significantly reduced by 0.38-fold (p < 0.01) and 0.48-fold (p < 0.01), indicating that AjFPN was an important factor in the introduction of ferroptosis into intracellular bacteria. Overall, our findings indicated that ferroptosis could resist intracellular AJ01 infection via AjFPN. These findings provide a novel defense mechanism for aquatic animals against intracellular bacterial infection.

Ultra-small Janus nanoparticle-induced activation of ferroptosis for synergistic tumor immunotherapy

Ferroptosis induced by lipid peroxide (LPO) accumulation is an effective cell death pathway for cancer therapy. However, how to effectively induce ferroptosis at tumor sites and improve its therapeutic effectiveness remains challenging. Here, MnFe2O4@NaGdF4@NLG919@HA (MGNH) nanocomplex with tumor-specific targeting and TME response is constructed to overcome immunosuppressive tumor microenvironment (TME) to potentiate the curative effect of ferroptosis by coupling the immune checkpoint indoleamine 2,3-dioxygenase (IDO) inhibitor, NLG919, and hyaluronic acid (HA) to novel ultra-small MnFe2O4@NaGdF4 (MG) nanoparticles with a Janus structure. Firstly, tumor site-precise delivery of MG and NLG919 is achieved with HA targeting. Secondly, MG acts as a magnetic resonance imaging contrast agent, which not only has a good photothermal effect to realize tumor photothermal therapy, but also depletes glutathione and catalyzes the production of reactive oxygen species from endogenous H2O2, which effectively promotes the accumulation of LPO and inhibits the expression of glutathione peroxidase 4, achieving enhanced ferroptosis. Thirdly, NLG919 inhibits the differentiation of Tregs by blocking the tryptophan/kynurenine immune escape pathway, thereby reversing immunosuppressive TME together with the Mn2+-activated cGAS-STING pathway. This work contributes new perspectives for the development of novel ultra-small Janus nanoparticles to reshape immunosuppressive TME and ferroptosis activation. Statement of significanceThe Janus structured MnFe2O4@NaGdF4@NLG919@HA (MGNH) nanocomplex was synthesized, which can realize the precise delivery of T1/T2 contrast agents MnFe2O4@NaGdF4 (MG) and NLG919 at the tumor site under the ultra-small Janus structural characteristics and targeted molecule HA. The production of ROS, consumption of GSH, and photothermal properties of MGNH make it possible for CDT/PTT activated ferroptosis, and synergistically disrupt and reprogram tumor growth and immunosuppressive tumor microenvironment with NLG919 and Mn2+-mediated activation of cGAS-STING pathway, achieving CDT/PTT/immunotherapy activated by ferroptosis. Meanwhile, ultra-small structural properties of MGNH facilitate subsequent metabolic clearance by the body, allowing for the minimization of potential biotoxicity associated with its prolonged retention.

Butylated hydroxyanisole induces vascular endothelial injury via TFEB-mediated degradation of GPX4 and FTH1

Butylated hydroxyanisole (BHA) is one of the most commonly used antioxidants and is widely used in food, but whether it causes vascular damage has not been clearly studied. The present study demonstrated for the first time that BHA reduced the viability of human umbilical vein endothelial cells (HUVECs) and mouse brain microvascular endothelial cells (BEND3) in a dose- and time-dependent manner. Moreover, BHA inhibited the migration and proliferation of vascular endothelial cells (ECs). Further analysis revealed that in ECs, the ferroptosis inhibitor ferrostatin-1 (Fer-1) reversed the BHA-induced increase in Fe2+ and malonaldehyde (MDA) levels. Acridine orange staining demonstrated that BHA increased lysosomal permeability. At the protein level, BHA increased the expression of transcription factor EB (TFEB) and decreased the expression of glutathione peroxidase (GPX4), solute carrier family 7 member 11 (SLC7A11, xCT), and ferritin heavy chain 1 (FTH1). Moreover, these effects of BHA could be reversed by knocking down TFEB. In vivo experiments confirmed that BHA caused elevated pulse wave velocity (PWV) and reduced acetylcholine-dependent vascular endothelial diastole. In conclusion, BHA degrades GPX4, xCT, and FTH1 through activation of the TFEB-mediated lysosomal pathway and promotes ferroptosis, ultimately leading to vascular endothelial cell injury.

Phospholipase PLA2G7 is complementary to GPX4 in mitigating punicic-acid-induced ferroptosis in prostate cancer cells

Ferroptosis is a cell death pathway that can be promoted by peroxidizable polyunsaturated fatty acids in cancer cells. Here, we investigated the mechanisms underlying the toxicity of punicic acid (PunA), an isomer of conjugated linolenic acids (CLnAs) bearing three conjugated double bonds highly prone to peroxidation, on prostate cancer (PCa) cells. PunA induced ferroptosis in PCa cells and triggered massive lipidome remodeling, more strongly in PC3 androgen-negative cells than in androgen-positive cells. The greater sensitivity of androgen-negative cells to PunA was associated with lower expression of glutathione peroxidase 4 (GPX4). We then identified the phospholipase PLA2G7 as a PunA-induced ferroptosis suppressor in PCa cells. Overexpressing PLA2G7 decreased lipid peroxidation levels, suggesting that PLA2G7 hydrolyzes hydroperoxide-containing phospholipids, thus preventing ferroptosis. Importantly, overexpressing both PLA2G7 and GPX4 strongly prevented PunA-induced ferroptosis in androgen-negative PCa cells. This study shows that PLA2G7 acts complementary to GPX4 to protect PCa cells from CLnA-induced ferroptosis.

ALKBH5 Modulates Asthma Progression by Downregulating N6-methyladenosine Methylation.

Asthma is a chronic respiratory disease that is characterized by airway inflammation, excessive mucus production, and airway remodeling. Prevention and treatment for asthma is an urgent issue in clinical studies. In recent years, N6-methyladenosine methylation (m6A) has emerged as a promising regulatory approach involved in multiple diseases. ALKBH5 (alkB homolog 5) is a demethylase widely studied in disease pathologies. This work aimed to explore the regulatory mechanisms underlying the ALKBH5-regulated asthma. We established an interleukin-13 (IL-13)-stimulated cell model to mimic the in vitro inflammatory environment of asthma. ALKBH5 knockdown in bronchial epithelial cells was performed using siRNAs, and the knockdown efficacy was analyzed by quantitative PCR (qPCR). Cell viability and proliferation were measured by cell counting kit 8 (CCK-8) and colony formation assay. The ferroptosis was assessed by measuring the total iron, Fe2+, lipid reactive oxygen species (ROS), malondialdehyde (MDA), and superoxide dismutase (SOD) levels. The enrichment of N6-methyladenosine methylation (m6A) modification was detected by the MeRIP assay. Knockdown of ALKBH5 significantly elevated the survival and colony formation ability of bronchial epithelial cells in the IL-13 induction model. The levels of total iron, Fe2+, lipid ROS, and MDA were remarkedly elevated, and the SOD level was reduced in IL-13-induced bronchial epithelial cells, and depletion of ALKBH5 reversed these effects. Knockdown of ALKBH5 elevated the enrichment of m6A modification and expression of glutathione peroxidase 4 (GPX4). Knockdown of GPX4 abolished the pro-proliferation and anti-ferroptosis effects of siALKBH5. Knockdown of ALKBH5 improved the proliferation of bronchial epithelial cells and alleviated cell ferroptosis.

Engineering Nanozymes for Tumor Therapy via Ferroptosis Self-Amplification.

Ferroptosis induction is an emerging strategy for tumor therapy. Reactive oxygen species (ROS) can induce ferroptosis but are easily consumed by overexpressed glutathione (GSH) in tumor cells. Therefore, achieving a large amount of ROS production in tumor cells without being consumed is key to efficiently inducing ferroptosis. In this study, a self-amplifying ferroptosis-inducing therapeutic agent, Pd@CeO2-Fe-Co-WZB117-DSPE-PEG-FA (PCDWD), is designed for tumor therapy. PCDWD exhibits excellent multi-enzyme activities due to the loading of Fe-Co dual atoms with abundant active sites, including peroxidase-like enzymes, catalase-like enzymes, and glutathione oxidases (GSHOx), which undergo catalytic reactions in the tumor microenvironment to produce ROS, thereby inducing ferroptosis. Furthermore, PCDWD can also deplete GSH in tumor cells, thus reducing the consumption of ROS by GSH and inhibiting the expression of GSH peroxidase 4. Moreover, the photothermal effect of PCDWD can not only directly kill tumor cells but also further enhance its own enzyme activities, consequently promoting ferroptosis in tumor cells. In addition, WZB117 can reduce the expression of heat shock protein 90 by inhibiting glucose transport, thereby reducing the thermal resistance of tumor cells and further improving the therapeutic effect. Finally, X-ray computed tomography imaging of PCDWD guides it to achieve efficient tumor therapy.

Metal-organic framework-mediated siRNA delivery and sonodynamic therapy for precisely triggering ferroptosis and augmenting ICD in osteosarcoma

The complex genomics, immunosuppressive tumor microenvironment (TME), and chemotherapeutic resistance of osteosarcoma (OS) have resulted in limited therapeutic effects in the clinic. Ferroptosis is involved in tumor progression and is regulated mainly by glutathione peroxidase 4 (GPX4). Small interfering RNA (siRNA)-based RNA interference (RNAi) can precisely target any gene. However, achieving effective siRNA delivery is highly challenging. Here, we fabricated a TME-responsive metal-organic framework (MOF)-based biomimetic nanosystem (mFeP@si) with siGPX4 delivery and sonodynamic therapy (SDT) to treat OS by targeting ferroptosis. Under ultrasound (US) irradiation, mFeP@si achieves lysosomal escape via singlet oxygen (1O2)-mediated lysosomal membrane disruption and then accelerates ROS generation and glutathione (GSH) depletion. Meanwhile, siGPX4 silences GPX4 expression by binding to GPX4 mRNA and leads to the accumulation of toxic phospholipid hydroperoxides (PL-OOH), further magnifying the ROS storm and triggering ferroptosis. Notably, synergistic therapy remarkably enhances antitumor effects, improves the immunosuppressive TME by inducing potent immunogenic cell death (ICD), and increases the sensitivity of chemotherapy-resistant OS cells to cisplatin. Overall, this novel nanosystem, which targets ferroptosis by integrating RNAi and SDT, exhibits strong antitumor effects both in vitro and in vivo, providing new insights for treating OS.

Orchestrating apoptosis and ferroptosis through enhanced sonodynamic therapy using amorphous UIO-66-CoOx

The development of efficient and multifunctional sonosensitizers is crucial for enhancing the efficacy of sonodynamic therapy (SDT). Herein, we have successfully constructed a CoOx-loaded amorphous metal-organic framework (MOF) UIO-66 (A-UIO-66-CoOx) sonosensitizer with excellent catalase (CAT)- and glutathione-oxidase (GSH-OXD)-like activities. The A-UIO-66-CoOx exhibits a 2.6-fold increase in singlet oxygen (1O2) generation under ultrasound (US) exposure compared to crystalline UIO-66 sonosensitizer, which is attributed to its superior charge transfer efficiency and consistent oxygen (O2) supply. Additionally, the A-UIO-66-CoOx composite reduces the expression of glutathione peroxidase (GPX4) by depleting glutathione (GSH) through Co3+ and Co2+ valence changes. The high levels of highly cytotoxic 1O2 and deactivation of GPX4 can lead to lethal lipid peroxidation, resulting in concurrent apoptosis and ferroptosis. Both in vitro and vivo tumor models comprehensively confirmed the enhanced SDT antitumor effect using A-UIO-66-CoOx sonosensitizer. Overall, this study emphasizes the possibility of utilizing amorphization engineering to improve the effectiveness of MOFs-based sonosensitizers for combined cancer therapies.

PTGER3 knockdown inhibits the vulnerability of triple-negative breast cancer to ferroptosis.

Prostaglandin E receptor 3 (PTGER3) is involved in a variety of biological processes in the human body and is closely associated with the development and progression of a variety of cancer types. However, the role of PTGER3 in triple-negative breast cancer (TNBC) remains unclear. In the present study, low PTGER3 expression was found to be associated with poor prognosis in TNBC patients. PTGER3 plays a crucial role in regulating TNBC cell invasion, migration, and proliferation. Upregulation of PTGER3 weakens the epithelial-mesenchymal phenotype in TNBC and promotes ferroptosis both invitro and invivo by repressing glutathione peroxidase 4 (GPX4) expression. On the other hand, downregulation of PTGER3 inhibits ferroptosis by increasing GPX4 expression and activating the PI3K-AKT pathway. Upregulation of PTGER3 also enhances the sensitivity of TNBC cells to paclitaxel. Overall, this study has elucidated critical pathways in which low PTGER3 expression protects TNBC cells from undergoing ferroptosis, thereby promoting its progression. PTGER3 may thus serve as a novel and promising biomarker and therapeutic target for TNBC.

The navel nanoethosomal formulation of gamma-oryzanol attenuates testicular ischemia/reperfusion damages

Testicular torsion reduces blood flow to testes and induces tissue ischemia. Antioxidant can have pivotal roles in alleviation of the effects of torsion/reperfusion. Gamma-oryzanol (γ-Oryzanol) has several pharmacological properties such as antioxidant and anti-apoptosis that can be used in this way. This study was conducted to evaluate the effects of nanoethosomal formulation of gamma-oryzanol (γ-Oryzanol-NEs) on testicular damages in a mouse model of ischemia/reperfusion damage. Following induction of ischemia/reperfusion, the mice were treated with γ-Oryzanol and γ-Oryzanol-NEs (6 mg/kg) in times of 3 h and 6 h. The expression of positive cells of TUNEL, superoxide dismutase (SOD), glutathione peroxidase (GPx), heat shock protein-70 (HSP70) and caspase 3 and histopathological parameters were assessed. The results showed higher expression of positive cells of TUNEL, HSP70 and caspase 3 and lower expressions of SOD and GPx in control mice compared with those treated with γ-Oryzanol-NEs (P = 0.001). The treatment with γ-Oryzanol-NEs could decrease pathological damages and the expression of positive cells of TUNEL, HSP70 and caspase 3 and increase the expressions of SOD and GPx. In conclusion, γ-Oryzanol-NEs could have the protective effects on torsion/reperfusion by decreasing apoptosis and increasing antioxidant status in a mouse model.

Protective Role of Dioscin against Doxorubicin-Induced Chronic Cardiotoxicity: Insights from Nrf2-GPX4 Axis-Mediated Cardiac Ferroptosis.

Recent evidence suggests that ferroptosis, an iron-facilitated cell death with excessive lipid peroxidation, is a critical mechanism underlying doxorubicin (DOX)-induced cardiotoxicity (DIC). Although dioscin has been reported to improve acute DIC, direct evidence is lacking to clarify the role of dioscin in chronic DIC and its potential mechanism in cardiac ferroptosis. In this study, we used chronic DIC rat models and H9c2 cells to investigate the potential of dioscin to mitigate DIC by inhibiting ferroptosis. Our results suggest that dioscin significantly improves chronic DIC-induced cardiac dysfunction. Meanwhile, it significantly inhibited DOX-induced ferroptosis by reducing Fe2+ and lipid peroxidation accumulation, maintaining mitochondrial integrity, increasing glutathione peroxidase 4 (GPX4) expression, and decreasing acyl-CoA synthetase long-chain family 4 (ACSL4) expression. Through transcriptomic analysis and subsequent validation, we found that the anti-ferroptotic effects of dioscin are achieved by regulating the nuclear factor-erythroid 2-related factor 2 (Nrf2)/GPX4 axis and Nrf2 downstream iron metabolism genes. Dioscin further downregulates nicotinamide adenine dinucleotide phosphate oxidase 4 (NOX4) and upregulates expression of frataxin (FXN) and ATP-binding cassette B8 (ABCB8) to limit mitochondrial Fe2+ and lipid peroxide accumulation. However, Nrf2 inhibition diminishes the anti-ferroptotic effects of dioscin, leading to decreased GPX4 expression and increased lipid peroxidation. This study is a compelling demonstration that dioscin can effectively reduce DIC by inhibiting ferroptosis, which is dependent on the Nrf2/GPX4 pathway modulation.

Exploration of the immune response of grass carp (Ctenopharyngodon idellus) erythrocytes during bacterial infection

In teleost blood, red blood cells (RBCs) are the most common type of cell, and they differ from mammalian RBCs in having a nucleus and other organelles. As nucleated cells, teleost RBCs contribute to the immune response against pathogens, but their antibacterial mechanism remains unclear. Here, we utilized RNA-Seq to analyze gene expression patterns of grass carp (Ctenopharyngodon idellus) RBCs (GcRBCs) stimulated by Aeromonas hydrophila, Escherichia coli, and Staphylococcus aureus. Our transcriptomic data showed that bacterial stimulation generated many differentially expressed genes (DEGs). Furthermore, several inflammatory pathways responded to bacterial activation, and the TLR, IL-17, and tumor necrosis factor (TNF) signaling pathways were significantly activated based on Kyoto Encyclopedia of Genes and Genomes (KEGG) enrichment analysis. Furthermore, the findings of qRT-PCR showed markedly elevated expression of various cytokines, including IL-1β, IL4, IL6, IL8, IL12, and TNFα, in GcRBCs after incubation with bacteria. Reactive oxygen species (ROS) production in GcRBCs was markedly increased after the cells were stimulated with the three bacteria, and the expression of superoxide dismutase, glutathione peroxidase, and antioxidant enzymes, including catalase, was altered. Flow cytometry analysis showed that the apoptosis rate of GcRBCs was enhanced after stimulation with the three bacteria for different times. In summary, our findings reveal that bacterial stimulation activates the immune response of GcRBCs by regulating ROS release, cytokine expression, and the antioxidant system, leading to apoptosis of GcRBCs.

Aristolochic acid induces acute kidney injury through ferroptosis.

Aristolochic acid (AA)-induced acute kidney injury (AKI) presents with progressive decline in renal function and rapid progression to end-stage renal disease. Among the multiple mechanisms identified in AKI, ferroptosis has been shown to be involved in various forms of AKI. But few studies have elucidated the role of ferroptosis in AA-induced AKI. In this study, we investigated the role of ferroptosis in AA-induced acute renal tubular injury in vivo and in vitro. Mice with acute aristolochic acid nephropathy showed increased malondialdehyde levels, aggravated lipid peroxidation, decreased superoxide dismutase activity, and glutathione depletion. The expression of glutathione peroxidase 4 was decreased and the expression of acyl-CoA synthetase long-chain family member 4 was increased. Inhibition of ferroptosis by ferrostatin-1 significantly improved the renal function, reduced histopathological lesions, partially alleviated lipid peroxidation, and restored the antioxidant capacity. In vitro studies also revealed that AA significantly reduced cell viability, induced reactive oxygen species production, increased intracellular iron level and decreased ferroptosis-related protein expression. Inhibition of ferroptosis significantly increased cell viability and attenuated AA-induced renal tubular epithelial cell injury. It is suggested that ferroptosis plays an important role in AA-induced acute tubular injury. And inhibition of ferroptosis may exert renoprotective effects possibly by preventing lipid peroxidation, restoring the antioxidant activity or regulating iron metabolism.

BRCA1-Mediated Dual Regulation of Ferroptosis Exposes a Vulnerability to GPX4 and PARP Co-Inhibition in BRCA1-Deficient Cancers.

Resistance to poly (ADP-ribose) polymerase inhibitors (PARPi) limits the therapeutic efficacy of PARP inhibition in treating breast cancer susceptibility gene 1 (BRCA1)-deficient cancers. Here we reveal that BRCA1 has a dual role in regulating ferroptosis. BRCA1 promotes the transcription of voltage-dependent anion channel 3 (VDAC3) and glutathione peroxidase 4 (GPX4); consequently, BRCA1 deficiency promotes cellular resistance to erastin-induced ferroptosis but sensitizes cancer cells to ferroptosis induced by GPX4 inhibitors (GPX4i). In addition, nuclear receptor coactivator 4 (NCOA4)-mediated ferritinophagy and defective GPX4 induction unleash potent ferroptosis in BRCA1-deficient cancer cells upon PARPi and GPX4i co-treatment. Finally, we show that xenograft tumors derived from patients with BRCA1-mutant breast cancer with PARPi resistance exhibit decreased GPX4 expression and high sensitivity to PARP and GPX4 co-inhibition. Our results show that BRCA1 deficiency induces a ferroptosis vulnerability to PARP and GPX4 co-inhibition and inform a therapeutic strategy for overcoming PARPi resistance in BRCA1-deficient cancers. Significance: BRCA1 deficiency promotes resistance to erastin-induced ferroptosis via blocking VDAC3 yet renders cancer cells vulnerable to GPX4i-induced ferroptosis via inhibiting GPX4. NCOA4 induction and defective GPX4 further synergizes GPX4i with PARPi to induce ferroptosis in BRCA1-deficient cancers and targeting GPX4 mitigates PARPi resistance in those cancers. See related commentary by Alborzinia and Friedmann Angeli, p. 1372.

Edaravone dexborneol protects against cerebral ischemia/reperfusion-induced blood-brain barrier damage by inhibiting ferroptosis via activation of nrf-2/HO-1/GPX4 signaling

PurposeFerroptosis has recently been recognized as a mechanism of cerebral ischemia-reperfusion (I/R) injury, attributed to blood-brain barrier (BBB) disruption. Edaravone dexboneol (Eda.B) is a novel neuroprotective agent widely employed in ischemic stroke, which is composed of edaravone (Eda) and dexborneol. This study aimed to investigate the protective effects of Eda.B on the BBB in cerebral I/R and explore its potential mechanisms. MethodsTransient middle cerebral artery occlusion (tMCAO) Sprague-Dawley-rats model was used. Rats were randomly assigned to sham-operated group (sham, n = 20), model group (tMCAO, n = 20), Eda.B group (Eda.B, n = 20), Eda group (Eda, n = 20) and dexborneol group (dexborneol, n = 20), and Eda.B + Zinc protoporphyria group (Eda.B + ZnPP, n = 5). Infarct area, cellular apoptosis and neurofunctional recovery were accessed through TTC staining, TUNEL staining, and modified Garcia scoring system, respectively. BBB integrity was evaluated via Evans blue staining. Nuclear factor E2 related factor 2 (Nrf-2)/heme oxygenase 1 (HO-1)/glutathione peroxidase 4 (GPX4) signaling were qualified by Western blot. Transmission electron microscopy (TEM) revealed alterations in ipsilateral brain tissue among groups. Glutathione (GSH) and malondialdehyde (MDA) levels, and Fe2+ tissue content determination were detected. ResultsEda.B effectively improved neurological deficits, diminished infarct area and cellular apoptosis, as well as ameliorated BBB integrity in tMCAO rats. Further, Eda.B significantly inhibited ferroptosis, as evidenced by ameliorated pathological features of mitochondria, down-regulated of MDA and Fe2+ levels and up-regulated GSH content. Mechanistically, Eda.B attenuated BBB disruption via Nrf-2-mediated ferroptosis, promoting nuclear translocation of Nrf-2, increasing HO-1, GPX4 expression, alleviating the loss of zonula occludens 1 (ZO-1) and occludin as well as decreasing 4-hydroxynonenal (4-HNE) level. ConclusionsThis study revealed for the first time that Eda.B safeguarded the BBB from cerebral I/R injury by inhibiting ferroptosis through the activation of the Nrf-2/HO-1/GPX4 axis, providing a novel insight into the neuroprotective effect of Eda.B in cerebral I/R.

Ischemia-inhibited ferric chelate reductase 1 improves ferroptosis-mediated intestinal ischemia injury via Hippo signaling

The precise mechanism of ferroptosis as a regulatory cell death in intestinal ischemia injury induced by vascular intestinal obstruction (Vio) remains to be elucidated. Here, we evaluated iron levels, glutathione peroxidase 4 (GPX4) and Acyl-CoA synthetase long-chain family member 4 (ACSL4) changes after intestinal ischemia injury to validate ferroptosis. As an enzyme for Fe3+ reduction to Fe2+, Ferric Chelate Reductase 1 (FRRS1) is involved in the electron transport chain and the tricarboxylic acid (TCA) cycle in mitochondria. However, whether it is involved in ferroptosis and its role in intestinal ischemia injury need to be clarified. In the present study, FRRS1 was overexpressed in vivo and in vitro. The results showed that overexpression of FRRS1 prevented ischemia-induced iron levels, reactive oxygen species (ROS) production, lipid peroxidation, inflammatory responses, and cell death. Meanwhile, FRRS1 overexpression promoted GPX4 expression and suppressed ACSL4 levels. Further studies revealed that FRRS1 overexpression inhibited the activity of large tumor suppressor 1 (LATS1) / Yes-associated protein (YAP) / transcriptional co-activator with PDZ-binding motif (TAZ), a key component of Hippo signaling. In conclusion, this study demonstrates that FRRS1 is intimately involved in the inhibition of ferroptosis and thus protection of the intestine from intestinal ischemia injury, its downstream mechanism was related to Hippo signaling. These data provide new sight for the prevention and treatment of intestinal ischemia injury.

Systemic Oxidative Balance Reflects the Liver Disease Progression Status for Primary Biliary Cholangitis (Pbc): The Narcissus Fountain.

Biological antioxidant potential (BAP) and Reactive Oxygen Metabolites (dROMs) are two tests complementarily assessing systemic oxidative statuses (SOSs) that are never applied in chronic liver disorders (CLDs). We enrolled 41 ursodeoxycholic acid (UDCA)-naïve Primary Biliary Cholangitis (PBC) patients [age: 58.61 ± 11.26 years; females (F): 39], 40 patients with metabolic-dysfunction-associated steatotic livers (age: 54.30 ± 11.21; F: 20), 52 patients with HBV (age: 52.40 ± 8.22; F: 34), 50 patients with (age: 56.44 ± 7.79, F: 29), and 10 controls (age: 52.50 ± 9.64; F: 7). Liver fibrosis and the steatosis severity were determined using transient elastography, and the SOS was balanced using d-ROMs and the BAP test. The gene expressions of superoxide dismutase (SOD1; SOD2) and glutathione peroxidase (GPx1) were evaluated using real-time PCR in advanced fibrosis (AF: F3F4) in patients with PBC. In contrast to other CLDs, in PBC the dROMs and BAP levels were, respectively, directly and inversely correlated with hepatic fibrosis (dROMs, R: 0.883; BAP, R: -0.882) and steatosis (dROMs, R: 0.954; BAP, R: -0931) severity (p < 0.0001 all). Patients with PBC also revealed a progressively increasing trend of d-ROMs (F0-F2 vs. F3: p = 0.0008; F3 vs. F4: p = 0.04) and reduction in BAP levels (F0-F2 vs. F3: p = 0.0007; F3 vs. F4 p = 0.04) according to the worsening of liver fibrosis. In AF-PBC, the SOD1, SOD2, and GPx1 expressions were significantly downregulated in patients presenting SOS imbalance (SOD1, p = 0.02; SOD2, p = 0.03; GPx1, p = 0.02). SOS disequilibrium represents a leitmotiv in patients with PBC, perfectly reflecting their liver disease progression status.

Abstract 5220: Reduced expression of Glutathione peroxidase 2 (GPX2) is an independent predictor of poor prognosis in muscle-invasive urothelial carcinoma of the bladder

Abstract Background: The Glutathione peroxidase 2 (GPX2) is a selenium-dependent glutathione peroxidase with a pivotal role in removing potentially harming reactive oxygen species (ROS) from cells by catalyzing the reduction process of hydrogen peroxide to water. GPX2 is strongly expressed in normal urothelium but can be reduced in urothelial cancer. The aim of the study was to evaluate the potential clinical significance of GPX2 expression in urothelial bladder cancer. Design: GPX2 was analyzed by immunohistochemistry (IHC) in more than 2,500 urothelial bladder carcinomas in a tissue microarray format. Follow-up data were available for more than 600 patients with muscle-invasive disease. Results: GPX2 staining occurred in 67.5% of urothelial carcinomas including 11.4% with weak, 11.9% with moderate, and 44.2% with strong staining. While GPX2 staining was always strong in normal urothelium, it decreased markedly during grade and stage progression. Within pTa tumors, GPX2 positivity continuously decreased from pTaG2 low grade (99.4% positive) to pTa G2 high grade (97.2% positive) and to pTa G3 (90.5%; p=0.0013) while there was a marked further drop of GPX2 positivity from pTaG3 to muscle-invasive cancers (56.6%; p&amp;lt;0.0001 for pT2-4 vs. pTa G3). Within pT2-4 carcinomas, low or absent GPX2 staining was significantly linked to poor overall survival (p=0.0140), V1 (p&amp;lt;0.0001), L1 (p=0.0014), and high grade (p=0.0091), but statistically unrelated to pT and pN. In a multivariate analysis, the prognostic impact of reduced GPX2 expression (p=0.0081) was independent of pT (p&amp;lt;0.0001) and pN (p&amp;lt;0.0001) in pT2-4 tumors. GPX2 expression loss was inversely related to the expression of the luminal subtype markers GATA3 (p&amp;lt;0.0001), uroplakin 1b (p&amp;lt;0.0001) and cytokeratin 20 (p&amp;lt;0.0001) in pT2-4 carcinomas. Conclusion: GPX2 expression loss is a common event during bladder cancer progression which is strongly associated with poor prognosis in patients with pT2-4 urothelial carcinomas. GPX2 expression measurement - optimally together with other markers - could be useful for clinical risk assessment of bladder cancer patients. Citation Format: Henning Plage, Sebastian Hofbauer, Kira Furlano, Sarah Weinberger, Antonia Franz, Annika Fendler, Joachim Weischenfeldt, Florian Roßner, Simon Schallenberg, Sefer Elezkurtaj, Martina Kluth, Andreas H. Marx, Henrik Samtleben, Margit Fisch, Marcin Slojewski, Krystian Kaczmarek, Thorsten Ecke, Stefan Koch, Nico Adamini, Ronald Simon, Guido Sauter, Henrik Zecha, Tobias Klatte, Sarah Minner, David Horst, Thorsten Schlomm, Michael Rink, Maximilian Lennartz. Reduced expression of Glutathione peroxidase 2 (GPX2) is an independent predictor of poor prognosis in muscle-invasive urothelial carcinoma of the bladder [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2024; Part 1 (Regular Abstracts); 2024 Apr 5-10; San Diego, CA. Philadelphia (PA): AACR; Cancer Res 2024;84(6_Suppl):Abstract nr 5220.

Abstract 3787: Important role of GPX1 and NF-kb signaling pathway in human gastric cancer including cell proliferation and invasion

Abstract Background: Glutathione peroxidases(GPXs) are member of an antioxidant enzyme family. Their role is to eliminate the reactive oxygen species(ROS). Many available studies confirm that over expression of GPXs can promote cancer cell proliferation and invasion. Among the 8 GPXs, Glutathione peroxidase-1 (GPX1) is the most plentiful. Overexpression of GPX1 has been noted to promote invasion, migration, cisplatin resistance and proliferation in breast, colorectal and lung cancer. NF-kB is a ubiquitous nuclear transcription factor in the human body. that key role in cell proliferation, apoptosis and tumor progression. In reliable studies, inhibition of NF-kB expression has been shown to reduce the malignancy of Esophageal squamous cell carcinoma. Accordingly, the purpose of this study is to identify the GPX1 and NF-kB signaling pathway and their correlation with cancer cell proliferation and invasion in vitro using gastric cancer cell. Methods: In our study, we used cell culture, Northern blotting, cDNA microarray analysis, western blotting, RT-PCR, Zymography, 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide(MTT) assay, GPX1 knock-down with short hairpin RNS(shRNA), Standard two-chamber invasion assay, Chromatin immunoprecipitation assay. Results: First, we confirmed that the expression level of GPX1 was up-regulated by HGF(hepatocyte growth factor) in gastric cancer cells. The cells were treated with NF-kB inhibitor, Pyrrolidine dithiocarbamate(PDTC), and analyzed by Western blotting to identify the associated pathway of HGF-induced GPX1 with NF-kB. The HGF-induced GPX1 protein level was down regulated by PDTC. The role of GPX1 associated with NF-kB was determined by knock down GPX1 expression using GPX1-sh RNA. The GPX1-sh RNA treated cells showedvdown regulation of NF-kB and urokinase Plasminogen activator(uPA) also. To fine the upper regulator of GPX1 signaling pathway, we treated AKT inhibitor(LY294002) ant then analyzed by Western blotting to identify associated pathway of HGF-induced GPX1 with AKT. When AKT pathway was inhibited, GPX1 and NF-kB were down-regulated in gastric cancer cell. HGF-mediated cell proliferation and invasion in vitro was decreased in GPX1 knock down cell. We identified the putative binding site of GPX1 promotor containing NF-kB binding site and confirmed the function by CHIP assay. Conclusions: This study aimed to investigate relationship between GPX1 and NF-kB in gastric cancer cells. Results showed that HGF induced GPX1 expression through the NF-kB and AKT pathway and GPX1 may play a significant role in cell proliferation and invasion in gastric cancer. Therefore, GPX1 can be a potential therapeutic target of gastric cancer for the treatment. Citation Format: Byeong Il Jang, Ji Yoon Jung, Sung Ae Koh, Kyung Hee Lee. Important role of GPX1 and NF-kb signaling pathway in human gastric cancer including cell proliferation and invasion [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2024; Part 1 (Regular Abstracts); 2024 Apr 5-10; San Diego, CA. Philadelphia (PA): AACR; Cancer Res 2024;84(6_Suppl):Abstract nr 3787.