Downregulation Of Glutathione Peroxidase Research Articles

MoS2 Nanosheets at Low Doses Induced Cardiotoxicity in Developing Zebrafish via Ferroptosis: Influence of Lateral Size and Surface Modification.

The widespread applications of molybdenum disulfide (MoS2) nanosheets inevitably result in their release into aquatic environments, necessitating an exploration of their potential toxic effects on aquatic organisms. This study analyzes the cardiac responses of zebrafish larvae exposed to MoS2, with a focus on the influence of size and surface modifications. At higher concentrations (1 and 5 mg/L), MoS2 nanosheets hampered larval growth without influencing cardiomyogenesis. At lower doses (0.5-100 μg/L), small-sized MoS2 (ssMoS2, 187.2 nm) significantly impaired cardiac development, as proved by morphology abnormality, decreased heartbeat, stroke volume, and cardiac output, whereas these undesirable changes were not observed in the cysteine-modified form. Large-sized nanosheets (1.638 μm) did not localize to the heart, barely showing a cardiac disorder. Transcriptomics, biochemical analysis, and computational simulation validated that ssMoS2 aggravated Fe2+ overload through excessive ferritinophagy and ferroportin-1 inhibition, accompanied by down-regulation of glutathione peroxidase 4 and activation of PUFAs esterification, leading to ferroptosis. Significant associations between ferroptosis signals and cardiac indices, along with the ferrostatin-1 inhibition test, confirmed the ferroptosis-mediated cardiotoxicity of ssMoS2. Our study provides a key understanding of molecular events underlying MoS2-induced cardiotoxicity and highlights the importance of size and surface characteristics, which are significant for risk assessment and the safe design of nanoproducts.

Engineering Strain-Defects to Enhance Enzymatic Therapy and Induce Ferroptosis.

The effect of mimetic enzyme catalysis is often limited by insufficient activity and a single therapy is not sufficient to meet the application requirements. In this study, a multifunctional nanozyme, MMSR-pS-PEG, is designed and fabricated by modifying poly (ethylene glycol) grafted phosphorylated serine (pS-PEG) on mesoporous hollow MnMoOx spheres, followed by loading sorafenib (SRF) into the pores. Strain engineering-induced oxygen defects endow the nanozyme with enhanced dual-enzymatic activity to mimic catalase and oxidase-like activities, which catalyze the conversion of endogenous H2O2 into oxygen and subsequently into superoxide ions in the acidic tumor microenvironment. Moreover, as an n-type semiconductor, MnMoOx generates reactive oxygen species by separating electrons and holes upon ultrasonic irradiation and simultaneously deplete glutathione by holes, thereby further augmenting its catalytic effect. As a ferroptosis inducer, SRF restrains the system xc - and indirectly inhibits glutathione synthesis, synergistically interacting with the nanozyme to stimulate ferroptosis by promoting lipid peroxidation and accumulation and the downregulation of glutathione peroxidase 4. These results provide valuable insights into the design of enzymatic therapy with high performance and highlight a promising approach for the synergism of ferroptosis and enzymatic tumor therapy.

Albumin nanoassembly bi-directionally manipulated ferroptosis in tumor and CD8+T cells for triple-negative breast cancer therapy

Ferroptosis can serve as a potent strategy for regulating cell death via lipid peroxidation and the imbalance of the antioxidant system resulting from iron accumulation in triple-negative breast cancer (TNBC) therapy. However, the ferroptosis accompanied with down-regulation of glutathione peroxidase 4 (GPX4) lead to CD36-mediated tumor-infiltrating CD8+T cells uptaking fatty acids, resulting in the negative action on immunotherapeutic efficacy. Herein, the albumin nanoparticles, abbreviated as LHS NPs, were designed by co-assembly of hemin, linoleic acid-cystamine, and a CD36 inhibitor sulfosuccinimide oleate, to bi-directionally manipulated ferroptosis in tumor and CD8+T cells for TNBC therapy. LHS NPs exerted more efficient reactive oxygen species generation, glutathione depletion and malondialdehyde production by the combinatory strategy of classical and non-classical ferroptosis modes, which amplified the positive action on ferroptosis in tumor cells. Meanwhile, LHS manipulated the negative action of ferroptosis by inhibiting the CD36 mediated-lipid peroxidation in CD8+T cells, thereby activating the immunotherapeutic efficacy with the improvements on induction of immunogenic cell death, proliferation of CD4+CD8+T cells and natural killer cells, alleviation immunosuppressive regulatory T cells and myeloid-derived suppressor cells, and repolarization of the M2- to M1-phenotype tumor-associated macrophages. Thus, LHS NPs demonstrated an improved antitumor efficacy in suppressing the tumor growth and lung metastasis of 4T1-tumor mice. Our work gives novel insights for the bi-directionally manipulating ferroptosis in tumor and CD8+T cells on TNBC chemoimmunotherapy.

TYMS Knockdown Suppresses Cells Proliferation, Promotes Ferroptosis via Inhibits PI3K/Akt/mTOR Signaling Pathway Activation in Triple Negative Breast Cancer.

Triple-negative breast cancer (TNBC) is characterized by a grim prognosis and numerous challenges. The objective of our study was to examine the role of thymidylate synthase (TYMS) in TNBC and its impact on ferroptosis. The expression of TYMS was analyzed in databases, along with its prognostic correlation. TYMS positive expression was identified through immunohistochemistry (IHC), while real-time quantitative PCR (qRTPCR) was employed to measure TYMS mRNA levels in various cell lines. Western blotting was utilized to assess protein expression. Cell proliferation, mobility, apoptosis, and reactive oxygen species (ROS) levels were evaluated using CCK8, wound scratch healing assay, transwell assay, and flow cytometry, respectively. Additionally, a tumor xenograft model was established in BALB/c nude mice for further investigation. Tumor volume and weight were measured, and histopathological analysis using hematoxylin and eosin (H&E) staining was conducted to assess tumor tissue changes. IHC staining was employed to detect the expression of Ki67 in tumor tissues. High expression of TYMS was observed in TNBC and was found to be correlated with poor prognosis in patients. Among various cell lines, TYMS expression was highest in BT549 cells. Knockdown of TYMS resulted in suppression of cell proliferation and mobility, as well as promotion of apoptosis. Furthermore, knockdown of TYMS led to increased accumulation of ROS and Fe2+ levels, along with upregulation of ACLS4 expression and downregulation of glutathione peroxidase 4 (GPX4) expression. In vivo studies showed that knockdown of TYMS inhibited tumor growth. Additionally, knockdown of TYMS was associated with inhibition of mTOR, p-PI3K, and p-Akt expression. Our research showed that the knockdown of TYMS suppressed the TNBC progression by inhibited cells proliferation via ferroptosis. Its underlying mechanism is related to the PI3K /Akt pathway. Our study provides a novel sight for the suppression effect of TYMS on TNBC.

CircPDSS1 (hsa_circ_0017998) silencing induces ferroptosis in non-small-cell lung cancer cells by modulating the miR-137/SLC7A11/GPX4/GCLC axis

BackgroundCircular RNAs (circRNAs) regulate the tumorigenesis of non-small-cell lung cancer (NSCLC). CircPDSS1 (hsa_circ_0017998) has been newly discovered, and its role in NSCLC remains elusive. We aimed to investigate the functional roles and downstream targets of circPDSS1 in NSCLC cells. Materials and methodsCellular viabilities were measured through the Cell Counting Kit-8 (CCK-8) assay, whereas cell death was assessed through flow cytometry. The lactate dehydrogenase activity, malondialdehyde levels, ferrous iron, and reactive oxygen species were measured using commercial assay kits. The interaction between circPDSSA/ microRNA-137 (miR-137) and miR-137/solute carrier family 7 member 11 (SLC7A11) was assayed through a dual luciferase activity assay. Finally, the mRNA and protein levels were measured using real-time reverse transcriptase-polymerase chain reaction and western blots, respectively. ResultsCircPDSS1 expression was upregulated in NSCLC cells, compared with healthy lung cells. CircPDSS1 silencing suppressed the viability of NSCLC cells. Additionally, circPDSS1 knockdown induced ferroptosis rather than other types of cell death in NSCLC cells. Mechanically, circPDSS1 functions as a “sponge” to inversely control miR-137 expression, which directly targets SLC7A11. Moreover, circPDSS1 silencing causes the downregulation of glutathione peroxidase 4 (GPX4) and glutamate-cysteine ligase catalytic subunit (GCLC). ConclusionsTargeting the circPDSS1/miR-137/SLC7A11/GPX4/GCLC axis may be a promising strategy to kill NSCLC cells.

Glutathione peroxidase (GPX1) - Selenocysteine metabolism preserves the follicular fluid's (FF) redox homeostasis via IGF-1- NMD cascade in follicular ovarian cysts (FOCs)

Follicular ovarian cysts (FOCs) are characterized by follicles in the ovaries that are >20 mm in diameter and persist for >10 days without the corpus luteum, leading to anovulation, dysregulation of folliculogenesis and subfertility in humans and livestock species. Despite their clinical significance, the precise impact of FOCs on oocyte reserve, maturation, and quality still needs to be explored. While FOCs are observed in both human and livestock populations, they are notably prevalent in livestock species. Consequently, livestock species serve as valuable models for investigating the molecular intricacies of FOCs. Thus, in this study, using goat FOCs, we performed integrated proteomic, metabolomic and functional analyses to demonstrate that oocyte maturation is hampered due to increased reactive oxygen species (ROS) in FOCs follicular fluid (FF) via downregulation of glutathione peroxidase (GPX1), a critical antioxidant seleno enzyme required to negate oxidative stress. Notably, GPX1 reduction was positively correlated with the FF's decline of free selenium and selenocysteine metabolic enzymes, O-phosphoryl-tRNA (Sec) selenium transferase (SEPSECS) and selenocysteine lyase (SCLY) levels. Adding GPX1, selenocysteine, or selenium to the culture media rescued the oocyte maturation abnormalities caused by FOCs FF by down-regulating the ROS. Additionally, we demonstrate that substituting GPX1 regulator, Insulin-like growth factor-I (IGF-1) in the in vitro maturation media improved the oocyte maturation in the cystic FF by down-regulating the ROS activity via suppressing Non-sense-mediated decay (NMD) of GPX1. In contrast, inhibition of IGF-1R and the target of rapamycin complex 1 (mTORC1) hampered the oocyte maturation via NMD up-regulation. These findings imply that the GPX1 regulation via selenocysteine metabolism and the IGF-1-mediated NMD may be critical for the redox homeostasis of FF. We propose that GPX1 enhancers hold promise as therapeutics for enhancing the competence of FOCs oocytes. However, further in vivo studies are necessary to validate these findings observed in vitro.

Roles of β-catenin in innate immune process and regulating intestinal flora in Qi river crucian carp (Carassius auratus)

In mammals, β-catenin participates in innate immune process through interaction with NF-κB signaling pathway. However, its role in teleost immune processes remains largely unknown. We aimed to clarify the function of β-catenin in the natural defense mechanism of Qi river crucian carp (Carassius auratus). β-catenin exhibited a ubiquitous expression pattern in adult fish, as indicated by real-time PCR analysis. Following lipopolysaccharide (LPS), Polyinosinic-polycytidylic acid (polyI: C) and Aeromonas hydrophila (A. hydrophila) challenges, β-catenin increased in gill, intestine, liver and kidney, indicating that β-catenin likely plays a pivotal role in the immune response against pathogen infiltration. Inhibition of the β-catenin pathway using FH535, an inhibitor of Wnt/β-catenin pathway, resulting in pathological damage of the gill, intestine, liver and kidney, significant decrease of innate immune factors (C3, defb3, LYZ-C, INF-γ), upregulation of inflammatory factors (NF-κB, TNF-α, IL-1, IL-8), and downregulation of glutathione peroxidase (GSH-Px), superoxide dismutase (SOD) and catalase (CAT) activities, increase of Malondialdehyde (MDA) content. Following A. hydrophila invasion, the mortality rate in the FH535 treatment group exceeded that of the control group. In addition, the diversity of intestinal microflora decreased and the community structure was uneven after FH535 treatment. In summary, our findings strongly suggest that β-catenin plays a vital role in combating pathogen invasion and regulating intestinal flora in Qi river crucian carp.

BRMS1L confers anticancer activity in non-small cell lung cancer by transcriptionally inducing a redox imbalance in the GPX2-ROS pathway

Low expression levels of breast cancer metastasis suppressor 1 like (BRMS1L) have been associated with the growth of cancer cells. However, the mechanisms underlying the role of BRMS1L as an antitumour transcription factor in the progression of NSCLC have not been explored. Herein, we reveal that BRMS1L plays a key role as a tumour suppressor in inhibiting NSCLC proliferation and metastasis. Mechanistically, BRMS1L overexpression results in the downregulation of glutathione peroxidase 2 (GPX2) expression and consequently causes abnormal glutathione metabolism and increased levels of reactive oxygen species (ROS) in cells, inducing oxidative stress injury and apoptosis. Furthermore, overexpression of GPX2 enhances the growth advantage and oxidative stress repair conferred by knockdown of BRMS1L. Importantly, we show that low expression of BRMS1L in NSCLC cells causes relatively high levels of antioxidant accumulation to maintain cell redox balance and renders cancer cells more sensitive to treatment with piperlongumine as an ROS inducer both in vitro and in vivo. These findings offer new insights into the role of BRMS1L as a transcriptional repressor in NSCLC and suggest that the BRMS1L expression level may be a potential biomarker for predicting the therapeutic response to small molecule ROS inducers, providing new ideas for targeted therapy.

Mitochondria-targeted iridium(III) complexes encapsulated in liposome induce cell death through ferroptosis and gasdermin-mediated pyroptosis

This paper unveils a novel perspective on synthesis and characterization of the ligand 5-bromo-2-amino-2'-(phenyl-1H-imidazo[4,5-f][1,10]phenanthroline) (BAPIP), and its iridium(III) complexes [Ir(PPY−)2(BAPIP)](PF6) (1a, with PPY− as deprotonated 2-phenylpyridine), [Ir(PIQ−)2(BAPIP)](PF6) (1b, piq− denoting deprotonated 1-phenylisoquinoline), and [Ir(BZQ−)2(BAPIP)](PF6) (1c, bzq− signifying deprotonated benzo[h]quinoline). Systematic evaluation of the cytotoxicity of 1a, 1b, and 1c across diverse cell lines encompassing B16, HCT116, HepG2, A549, HeLa, and LO2 using 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide (MTT) method. Unexpectedly, compounds 1b and 1c demonstrated no cytotoxicity against the above cell lines. Motivated by the pursuit of heightened anti-proliferative potential, a strategic encapsulation approach yielded liposomes 1alip, 1blip, and 1clip. As expectation, 1alip, 1blip, and 1clip displayed remarkable anti-proliferative efficacy, particularly noteworthy in A549 cells, exhibiting IC50 values of 4.9 ± 1.0, 5.9 ± 0.1, and 7.6 ± 0.2 μM, respectively. Moreover, our investigation illuminated the mitochondrial accumulation of these liposomal entities, 1alip, 1blip, and 1clip, evoking apoptosis through the mitochondrial dysfunction mediated by reactive oxygen species (ROS). The ferroptosis was confirmed by decrease in glutathione (GSH) concentrations, the downregulation of glutathione peroxidase 4 (GPX4), increase of high mobility group protein 1 (HMGB1), and lipid peroxidation. Simultaneously, pyroptosis as another mode of cell death was undertaken. RNA-sequencing was employed to investigate intricate signalling pathways. In vivo examination provided tangible evidence of 1alip in effectively curbing tumor growth. Collectively, this study provides a multifaceted mode of cellular demise orchestrated by 1a, 1alip, 1blip, and 1clip, involving pathways encompassing apoptosis, ferroptosis, and pyroptosis.

Lens epithelium cell ferroptosis mediated by m6A-lncRNA and GPX4 expression in lens tissue of age-related cataract

BackgroundIn the present study, we explored the role of N6-methyladenosine (m6A) modification of long non-coding RNAs (lncRNAs) and its association with ferroptosis in lens epithelium cells (LECs) of age-related cataract (ARC).MethodsThrough m6A RNA immunoprecipitation sequencing (m6A-RIP-seq) and RNA sequencing (RNA-seq), we identified m6A mediated and differentially expressed lncRNAs (dme-lncRNAs) in ARC patients. Based on bioinformatics analysis, we selected critical dme-lncRNAs and pathways associated with ARC formation to reveal their potential molecular mechanisms. The downregulation of glutathione peroxidase 4 (GPX4), a key component of ferroptosis, was confirmed by real-time RT-PCR (RT-qPCR) and Western blotting in age-related cortical cataract (ARCC) samples. Transmission electron microscopy was used to assess the change in mitochondrial in LECs.ResultsThe analysis revealed a total of 11,193 m6A peaks within lncRNAs, among which 7043 were enriched and 4150 were depleted. Among those, lncRNA ENST00000586817(upstream of the GPX4 gene) was not only significantly upregulated in the LECs of ARCC but also potentially augmented the expression of GPX4 through a cis mechanism. The expression of m6A-modified lncRNA (ENST00000586817) was correlated with that of GPX4 and was downregulated in ARC patients. The TEM results indicated significant mitochondrial changes in ARCC samples. GPX4 downregulation enhanced LEC ferroptosis and decreased viability via RSL3 in SRA01/04 cells.ConclusionsOur results provide insight into the potential function of m6A-modified lncRNAs. M6A-modified lncRNA ENST00000586817 might regulate the expression of GPX4 by a cis mechanism and be implicated in ferroptosis in ARCs.

Trisulfide Bond-Mediated Molecular Phototheranostic Platform for "Activatable" NIR-II Imaging-Guided Enhanced Gas/Chemo-Hypothermal Photothermal Therapy.

Tumor microenvironment (TME)-triggered phototheranostic platform offers a feasible strategy to improve cancer diagnosis accuracy and minimize treatment side effects. Developing a stable and biocompatible molecular phototheranostic platform for TME-activated second near-infrared (NIR-II) fluorescence imaging-guided multimodal cascade therapy is a promising strategy for creating desirable anticancer agents. Herein, a new NIR-II fluorescence imaging-guided activatable molecular phototheranostic platform (IR-FEP-RGD-S-S-S-Fc) is presented for actively targeted tumor imaging and hydrogen sulfide (H2 S) gas-enhanced chemodynamic-hypothermal photothermal combined therapy (CDT/HPTT). It is revealed for the first time that the coupling distance between IR-FE and ferrocene is proportional to the photoinduced electron transfer (PET), and the aqueous environment is favorable for PET generation. The part of Cyclic-RGDfK (cRGDfk) peptides can target the tumor and benefit the endocytosis of nanoparticles. The high-concentration glutathione (GSH) in the TME will separate the fluorescence molecule and ferrocene by the GSH-sensitive trisulfide bond, realizing light-up NIR-II fluorescence imaging and a cascade of trimodal synergistic CDT/HPTT/gas therapy (GT). In addition, the accumulation of hydroxyl radicals (•OH) and down-regulation of glutathione peroxidase 4 (GPX4) can produce excessive harmful lipid hydroperoxides, ultimately leading to ferroptosis.

An Activatable Prodrug Nanosystem for Ultrasound-Driven Multimodal Tumor Therapy and Metastasis Inhibition.

Ultrasound, featuring deep tissue penetration and noninvasiveness, offers a new opportunity to activate functional materials in a tumor-selective manner. However, very few direct ultrasound-responsive redox systems are applicable under therapeutic ultrasound (1MHz). Herein, the investigations on nanoprodrug of DHE@PEG-SS-DSPE are reported, which exhibit glutathione-activated release of dihydroethidium (DHE) in tumor cells. DHE is stable with good biosafety and is transformed into cytotoxic ethidium to induce DNA damage under medical ultrasound irradiation, accompanied by the generation of reactive oxygen species. Further, DHE@PEG-SS-DSPE could effectively induce ferroptosis through glutathione depletion, lipid peroxide accumulation, and downregulation of glutathione peroxidase 4. In vivo studies confirmed that DHE@PEG-SS-DSPE nanoparticles effectively inhibit both the growth of solid tumors and the expression of metastasis-related proteins in mice, thus effectively inhibiting lung metastasis. This DHE-based prodrug nanosystem could lay a foundation for the design of ultrasound-driven therapeutic agents.

Baicalein, a component of banxia xiexin decoction, alleviates CPT-11-induced gastrointestinal dysfunction by inhibiting ALOX15-mediated ferroptosis.

Baicalein, one of the active ingredients of banxia xiexin decoction, has good therapeutic efficacy in treating diarrhea and improving gastrointestinal dysfunction. The role and mechanism of Baicalein on irinotecan (CPT-11)-induced gastrointestinal dysfunction are the focus of this study. Concretely, CPT-11 induced delayed diarrhea rat model and intestinal epithelial cell (IEC)-6 cell injury model with Baicalein treatment as needed. Colonic pathological changes were analyzed by hematoxylin-eosin staining, and inflammatory factor expressions in serum were determined by enzyme-linked immunosorbent assay. Immunohistochemistry and western blot were performed to quantify ferroptosis-related protein expressions. Thiobarbituric acid reactive substances (TBARS) kits and colorimetric assay kit were applied to detect lipid peroxidation levels and Fe2+ content, respectively. In vitro experiments also included quantitative real-time polymerase chain reaction, cell counting kit-8, and C11 BODIPY staining. CPT-11 induced aggravation of intestinal tissue damage, inflammatory factor release, Fe2+ accumulation, upregulation of lipid peroxidation and 15-Lipoxygenase (ALOX15) expression, and downregulation of glutathione peroxidase 4 (Gpx4) and SLC7A11 in vivo in rats; however, Baicalein dose-dependently reversed the effects of CPT-11. Baicalein elevated cell viability, reduced lipid peroxidation and Fe2+ accumulation, and elevated Gpx4 and SLC7A11 levels, whereas ALOX15 overexpression reversed the effects of Baicalein on a CPT-11-induced IEC-6 cell injury model. In conclusion, Baicalein plays a mitigating role in CPT-11-induced delayed diarrhea via ALOX15-mediated ferroptosis.

T-2 toxin induces cardiotoxicity by activating ferroptosis and inhibiting heme oxygenase-1

T-2 toxin, a natural secondary sesquiterpenoid metabolite produced by numerous strains of Fusarium fungi, is prevalent in both contaminated food and the environment. T-2 toxin is known to be highly toxic to the cardiovascular system, but the precise mechanisms that lead to T-2 toxin-induced cardiotoxicity are not yet fully understood. Recent findings indicate that ferroptosis is a pivotal factor in cardiovascular damage and exhibits a strong correlation with the detrimental impacts of T-2 toxin. The present study was designed to examine the involvement of ferroptosis in T-2 toxin-induced cardiac injury. Male mice and human cardiomyocytes were subjected to T-2 toxin for 24 h to induce acute cardiotoxicity for in vivo and in vitro studies, respectively. Our results demonstrated that T-2 toxin increased reactive oxygen species production, malondialdehyde, and decreased glutathione/oxidized glutathione and adenosine triphosphate levels. Furthermore, T-2 toxin was observed to activate ferroptosis, as evidenced by an increase in iron (Fe2+) concentration and upregulation of prostaglandin endoperoxide synthase 2, downregulation of glutathione peroxidase 4 and ferritin heavy chain 1, as well as ferroptotic morphological alterations. Inhibition of ferroptosis by Liproxstatin-1 reversed T-2 toxin-induced cardiac injury. Additionally, the downregulation of heme oxgenase-1 (HO-1) expression by T-2 toxin exacerbates ferroptosis and oxidative damage, which can be further aggravated by HO-1 inhibition with Sn-protoporphyrin. These findings provide novel insights into the mechanism of T-2 toxin-induced cardiotoxicity and suggest that targeting ferroptosis and HO-1 may represent a promising cardioprotective strategy against T-2 toxin.

Hippocampal ferroptosis is involved in learning and memory impairment in rats induced by microwave and electromagnetic pulse combined exposure

Microwave (MW) and electromagnetic pulse (EMP) are considered environmental pollutants, both of which can induce learning and memory impairments. However, the bioeffects of combined exposure to MW and EMP have never been explored. This paper aimed to investigate the effects of combined exposure to MW and EMP on the learning and memory of rats as well as its association with ferroptosis in the hippocampus. In this study, rats were exposed to EMP, MW, or EMP and MW combined radiation. After exposure, impairment of learning and memory, alterations in brain electrophysiological activity, and damage to hippocampal neurons were observed in rats. Moreover, we also found alterations in ferroptosis hallmarks, including increased levels of iron, lipid peroxidation, and prostaglandin-endoperoxide synthase 2 (PTGS2) mRNA, as well as downregulation of glutathione peroxidase 4 (GPX4) protein in the rat hippocampus after exposure. Our results suggested that either single or combined exposure to MW and EMP radiation could impair learning and memory and damage hippocampal neurons in rats. Moreover, the adverse effects caused by the combined exposure were more severe than the single exposures, which might be due to cumulative effects rather than synergistic effects. Furthermore, ferroptosis in the hippocampus might be a common underlying mechanism of learning and memory impairment induced by both single and combined MW and EMP exposure.

Interferon-γ induces salivary gland epithelial cell ferroptosis in Sjogren's syndrome via JAK/STAT1-mediated inhibition of system Xc-

The elevated level of interferon-γ (IFN-γ) in Sjogren's syndrome (SS) triggers salivary gland epithelial cells (SGEC) death. However, the underlying mechanisms of IFN-γ-induced SGEC death modes are still not fully elucidated. We found that IFN-γ triggers SGEC ferroptosis via Janus kinase/signal transducer and activator of transcription 1 (JAK/STAT1)-mediated inhibition of cystine-glutamate exchanger (System Xc−). Transcriptome analysis revealed that ferroptosis-related markers are differentially expressed in SS human and mouse salivary glands with distinct upregulation of IFN-γ and downregulation of glutathione peroxidase 4 (GPX4) and aquaporin 5 (AQP5). Inducing ferroptosis or IFN-γ treatment in the Institute of cancer research (ICR) mice aggravated and inhibition of ferroptosis or IFN-γ signaling in SS model non-obese diabetic (NOD) mice alleviated ferroptosis in the salivary gland and SS symptoms. IFN-γ activated STAT1 phosphorylation and downregulated system Xc− components solute carrier family 3 member 2 (SLC3A2), glutathione, and GPX4 thereby triggering ferroptosis in SGEC. JAK or STAT1 inhibition in SGEC rescued IFN-γ-downregulated SLC3A2 and GPX4 as well as IFN-γ-induced cell death. Our results indicate the role of ferroptosis in SS-related death of SGEC and SS pathogenicity.

Simvastatin inhibits hepatic stellate cells activation by regulating the ferroptosis signaling pathway

Background & aimsFerroptosis is a form of regulated cell death and its promotion in hepatic stellate cells (HSCs) attenuates liver fibrosis. Statins, which are 3-hydroxy-3-methylglutaryl-coenzyme A (HMG-CoA) reductase inhibitors, may induce ferroptosis via the downregulation of glutathione peroxidase 4 (GPX4) by inhibiting the mevalonate pathway. However, little evidence is available regarding the association between statins and ferroptosis. Therefore, we investigated the association between statins and ferroptosis in HSCs. MethodsTwo human HSC cell lines, LX-2 and TWNT-1, were treated with simvastatin, an HMG-CoA reductase inhibitor. Mevalonic acid (MVA), farnesyl pyrophosphate (FPP), and geranylgeranyl pyrophosphate (GGPP) were used to determine the involvement of the mevalonate pathway. We performed a detailed analysis of the ferroptosis signaling pathway. We also investigated human liver tissue samples from patients with nonalcoholic steatohepatitis to clarify the effect of statins on GPX4 expression. ResultsSimvastatin reduced cell mortality and inhibited HSCs activation, accompanied by iron accumulation, oxidative stress, lipid peroxidation, and reduced GPX4 protein expression. These results indicate that simvastatin inhibits HSCs activation by promoting ferroptosis. Furthermore, treatment with MVA, FPP, or GGPP attenuated simvastatin-induced ferroptosis. These results suggest that simvastatin promotes ferroptosis in HSCs by inhibiting the mevalonate pathway. In human liver tissue samples, statins downregulated the expression of GPX4 in HSCs without affecting hepatocytes. ConclusionsSimvastatin inhibits the activation of HSCs by regulating the ferroptosis signaling pathway.

SIRT3 Deficiency Enhances Ferroptosis and Promotes Cardiac Fibrosis via p53 Acetylation.

Cardiac fibrosis plays an essential role in the development of diastolic dysfunction and contributes to heart failure with preserved ejection fraction (HFpEF). Our previous studies suggested Sirtuin 3 (SIRT3) as a potential target for cardiac fibrosis and heart failure. In the present study, we explored the role of SIRT3 in cardiac ferroptosis and its contribution to cardiac fibrosis. Our data showed that knockout of SIRT3 resulted in a significant increase in ferroptosis, with increased levels of 4-hydroxynonenal (4-HNE) and downregulation of glutathione peroxidase 4 (GPX-4) in the mouse hearts. Overexpression of SIRT3 significantly blunted ferroptosis in response to erastin, a known ferroptosis inducer, in H9c2 myofibroblasts. Knockout of SIRT3 resulted in a significant increase in p53 acetylation. Inhibition of p53 acetylation by C646 significantly alleviated ferroptosis in H9c2 myofibroblasts. To further explore the involvement of p53 acetylation in SIRT3-mediated ferroptosis, we crossed acetylated p53 mutant (p534KR) mice, which cannot activate ferroptosis, with SIRT3KO mice. SIRT3KO/p534KR mice exhibited a significant reduction in ferroptosis and less cardiac fibrosis compared to SIRT3KO mice. Furthermore, cardiomyocyte-specific knockout of SIRT3 (SIRT3-cKO) in mice resulted in a significant increase in ferroptosis and cardiac fibrosis. Treatment of SIRT3-cKO mice with the ferroptosis inhibitor ferrostatin-1 (Fer-1) led to a significant reduction in ferroptosis and cardiac fibrosis. We concluded that SIRT3-mediated cardiac fibrosis was partly through a mechanism involving p53 acetylation-induced ferroptosis in myofibroblasts.

Shikonin and cisplatin synergistically overcome cisplatin resistance of ovarian cancer by inducing ferroptosis via upregulation of HMOX1 to promote Fe2+ accumulation

BackgroundCisplatin-based chemotherapy often results in ovarian cancer (OC) chemical resistance and treatment failure. The combination of natural compounds with platinum-based agents is a new strategy for overcoming cisplatin resistance. At present, the synergistic effects and mechanism of combination of shikonin and cisplatin to overcome cisplatin resistance in OC are still unknown. PurposeThis study was to evaluate the synergistic effects of shikonin and cisplatin on cisplatin-resistant OC cells and to assess the underlying molecular basis for these effects. MethodsCell counting kit-8 assay, colony-formation assay, proteomic analysis, reactive oxygen species (ROS) detection, lipid peroxidation (LPO) detection, Fe2+ detection, western blot, and quantitative real-time reverse transcription PCR (qRT-PCR) were performed to evaluate the effects of shikonin and cisplatin on cisplatin-resistant OC cells. Underlying mechanisms of action were investigated in vitro using small molecule inhibitors and siRNA. In vivo, the effect of shikonin and cisplatin combination on tumor growth in BALB/c nude mice was evaluated, with tumor immunohistochemical (IHC) staining performed to detect ferroptosis-related proteins. ResultsIn vitro, shikonin and cisplatin were shown to synergistically reduce the viability of cisplatin-resistant OC cells. Proteomic results demonstrated that the combination of the two drugs induced a ferroptotic process, as evidenced by increased levels of ROS, LPO, and Fe2+, with downregulation of glutathione peroxidase 4 (GPX4). Heme oxygenase 1 (HMOX1) inhibition and siRNA interference attenuated the combined effect of the two drugs on cell viability. Accumulation of Fe2+ was attenuated by siRNA interference of HMOX1. In vivo, combination treatment significantly inhibited the growth of subcutaneous tumors in BALB/c nude mice and increased the expression of ferroptosis-related proteins in tumor tissue. ConclusionWe report for the first time that the co-treatment of shikonin and cisplatin overcomes cisplatin resistance in OC through ferroptosis. Mechanistic analysis reveals the co-treatment induces ferroptosis through upregulation of HMOX1 that promotes Fe2+ accumulation.

Heme oxygenase-1 modulates ferroptosis by fine-tuning levels of intracellular iron and reactive oxygen species of macrophages in response to Bacillus Calmette-Guerin infection.

Macrophages are the host cells and the frontline defense against Mycobacterium tuberculosis (Mtb) infection, and the form of death of infected macrophages plays a pivotal role in the outcome of Mtb infections. Ferroptosis, a programmed necrotic cell death induced by overwhelming lipid peroxidation, was confirmed as one of the mechanisms of Mtb spread following infection and the pathogenesis of tuberculosis (TB). However, the mechanism underlying the macrophage ferroptosis induced by Mtb infection has not yet been fully understood. In the present study, transcriptome analysis revealed the upregulation of heme oxygenase-1 (HMOX1) and pro-ferroptosis cytokines, but downregulation of glutathione peroxidase 4 (GPX4) and other key anti-lipid peroxidation factors in the peripheral blood of both patients with extra-pulmonary tuberculosis (EPTB) and pulmonary tuberculosis (PTB). This finding was further corroborated in mice and RAW264.7 murine macrophage-like cells infected with Bacillus Calmette-Guerin (BCG). A mechanistic study further demonstrated that heme oxygenase-1 protein (HO-1) regulated the production of reactive oxygen species (ROS) and iron metabolism, and ferroptosis in BCG-infected murine macrophages. The knockdown of Hmox1 by siRNA resulted in a significant increase of intracellular ROS, Fe2+, and iron autophagy-mediated factor Ncoa4, along with the reduction of antioxidant factors Gpx4 and Fsp1 in macrophages infected with BCG. The siRNA-mediated knockdown of Hmox1 also reduced cell survival rate and increased the release of intracellular bacteria in BCG-infected macrophages. By contrast, scavenging ROS by N-acetyl cysteine led to the reduction of intracellular ROS, Fe2+, and Hmox1 concentrations, and subsequently inhibited ferroptosis and the release of intracellular BCG in RAW264.7 cells infected with BCG. These findings suggest that HO-1 is an essential regulator of Mtb-induced ferroptosis, which regulates ROS production and iron accretion to alter macrophage death against Mtb infections.