STAT3 signaling promotes cardiac injury by upregulating NCOA4-mediated ferritinophagy and ferroptosis in high-fat-diet fed mice. Free radical biology & medicine High-fat diet (HFD) intake provokes obesity and cardiac anomalies. Recent studies have found that ferroptosis plays a role in HFD-induced cardiac injury, but the underlying mechanism is largely unclear. Ferritinophagy is an important part of ferroptosis that is regulated by nuclear receptor coactivator 4 (NCOA4). However, the relationship between ferritinophagy and HFD-induced cardiac damage has not been explored. In this study, we found that oleic acid/palmitic acid (OA/PA) increased the level of ferroptotic events including iron and ROS accumulation, upregulation of PTGS2 mRNA and protein levels, reduced SOD and GSH levels, and significant mitochondrial damage in H9C2 cells, which could be reversed by the ferroptosis inhibitor ferrostatin-1 (Fer-1). Intriguingly, we found that the autophagy inhibitor 3-methyladenine mitigated OA/PA-induced ferritin downregulation, iron overload and ferroptosis. OA/PA increased the protein level of NCOA4. Knockdown of NCOA4 by SiRNA partly reversed the reduction in ferritin, mitigated iron overload and lipid peroxidation, and subsequently alleviated OA/PA-induced cell death, indicating that NCOA4-mediated ferritinophagy was required for OA/PA-induced ferroptosis. Furthermore, we demonstrated that NCOA4 was regulated by IL-6/STAT3 signaling. Inhibition or knockdown of STAT3 effectively reduced NCOA4 levels to protect H9C2 cells from ferritinophagy-mediated ferroptosis, whereas STAT3 overexpression by plasmid appeared to increase NCOA4 expression and contribute to classical ferroptotic events. Consistently, phosphorylated STAT3 upregulation, ferritinophagy activation, and ferroptosis induction also occurred in HFD-fed mice and were responsible for HFD-induced cardiac injury. In addition, we found evidence that piperlongumine, a natural compound, effectively reduced phosphorylated STAT3 levels to protect cardiomyocytes from ferritinophagy-mediated ferroptosis both in vitro and in vivo. Based on these findings, we concluded that ferritinophagy-mediated ferroptosis was one of the critical mechanisms contributing to HFD-induced cardiac injury. The STAT3/NCOA4/FTH1 axis might be a novel therapeutic target for the treatment of HFD-induced cardiac injury. 10.1016/j.freeradbiomed.2023.03.003

Melatonin Ameliorates Hepatic Ferroptosis in NAFLD by Inhibiting ER Stress via the MT2/cAMP/PKA/IRE1 Signaling Pathway. International journal of biological sciences Ferroptosis, an iron-dependent cell death form, has recently been observed in the development of non-alcoholic fatty liver disease (NAFLD). Melatonin (Mel) shows potential benefits for preventing and treating liver diseases. Whether and how Mel ameliorates hepatic ferroptosis in NAFLD is not fully understood. Here we established a mouse model of NAFLD induced by long-term high-fat diet (HFD) feeding. We found that Mel treatment ameliorated global metabolic abnormalities and inhibited the progression of NAFLD in mice. Most importantly, Mel supplementation significantly improved HFD-induced iron homeostasis disorders in the liver, including iron overload and ferritin transport disorders. For another, Mel ameliorated HFD-induced hepatic lipid peroxidation. The recuperative role of exogenous Mel on hepatocyte ferroptosis was also observed in PA- or Erastin-treated HepG2 cells. Mechanistically, MT2, but not MT1, was involved in the effect of Mel. Furthermore, Mel treatment inhibited HFD or Erastin-activated ER stress and activated the PKA/IRE1 signaling pathway. Co-expression of p-PKA and p-IRE1 was enhanced by the MT2 antagonist. Inhibitions of PKA and IRE1 respectively improved hepatocyte ferroptosis, and activations of cAMP/PKA reversed Mel's effect on ferroptosis. Collectively, these findings suggest that exogenous Mel inhibits hepatic ferroptosis in NAFLD by ameliorating ER stress through the MT2/cAMP/PKA/IRE1 pathway, proving that Mel is a promising candidate drug for the treatment of hepatic ferroptosis in NAFLD. 10.7150/ijbs.85883

Oral fecal transplantation enriches Lachnospiraceae and butyrate to mitigate acute liver injury. Cell reports While fecal microbiota transplantation (FMT) shows promise in treating human diseases, oral capsule FMT is more accepted and accessible to patients. However, microbe selection in the upper gastrointestinal tract (UGIT) through oral administration remains unclear. Here, we demonstrate that short-term oral fecal gavage (OFG) alleviates acetaminophen-induced acute liver injury (AILI) in mice, regardless of the divergent effects of commensal gut microbes. Pasteurized fecal gavage yields similar therapeutic effects. OFG enriches gut Lachnospiraceae and butyrate compared to donor feces. Butyrate mitigates AILI-induced ferroptosis via AMPK-ULK1-p62 signaling to simultaneously induce mitophagy and Nrf2 antioxidant responses. Combined N-acetylcysteine and butyrate administration significantly improves AILI mouse survival rates. These observations indicate the significance of the UGIT in modulating the implanted fecal microbes through oral administration and its potential biological and clinical impacts. Our findings also highlight a possible strategy for applying microbial metabolites to treat acute liver injury. 10.1016/j.celrep.2023.113591

Diesel exhaust PM2.5 greatly deteriorates fibrosis process in pre-existing pulmonary fibrosis via ferroptosis. Environment international Fine particulate matter (PM2.5) has been widely reported to contribute to the pathogenesis of pulmonary diseases. The direct hazardous effect of PM2.5 on the respiratory system at high concentrations in vitro and in vivo have been well identified. However, its effect on the pre-existing respiratory diseases of patients at environment-related concentrations remains unclear. Diesel exhaust PM2.5 as a primary representative of ambient PM2.5 fine particles were used to investigated the effect of PM2.5 on the fibrosis progression of existing pulmonary fibrosis disease models. This study reported that PM2.5 could result in the enhanced sensitivity to fibrotic response, which may be ascribed to ferroptosis induced by PM2.5 in damaged lung areas. Proteomic analysis revealed that the upregulation of HO-1 as a key mechanism in the ferroptosis and exacerbation of pulmonary fibrosis induced by PM2.5. As a result, HO-1 degraded heme-containing protein and released iron in fibrotic cells, leading to generation of mitochondrial ROS and impaired mitochondrial function. Transmission electron microscopic assay verified that PM2.5 entered the mitochondria of fibrotic cells and was accompanied by significant mitochondrial morphological changes characterized by increased mitochondrial membrane density and reduced mitochondrial size. The HO-1 inhibitor zinc protoporphyrin and mitochondrion-targeted antioxidant Mito-TEMPO significantly attenuated PM2.5-induced ferroptosis and exacerbation of fibrosis. In addition, AMPK-ULK1 axis-triggered autophagy activation and NCOA4-mediated degradation of ferritin by autophagy were found to be related to the PM2.5-induced ferroptosis of fibrotic cells. As evidenced by the inhibition of autophagy with 3-methyladenine or AMPK inhibitor, NCOA4 knockdown decreased intracellular iron accumulation and lipid peroxidation, thereby relieving PM2.5-induced epithelial-mesenchymal transition and cell death in fibrotic cells. Overall, this study provided experimental support for the idea that PM2.5 greatly deteriorates fibrosis process in pre-existing pulmonary fibrosis, and HO-1-mediated mitochondrial dysfunction and NCOA4-mediated ferritinophagy are jointly required for the PM2.5-induced ferroptosis and enhanced fibrosis effects. 10.1016/j.envint.2022.107706

Ferritinophagy is involved in the zinc oxide nanoparticles-induced ferroptosis of vascular endothelial cells. Qin Xia,Zhang Jun,Wang Bin,Xu Ge,Yang Xi,Zou Zhen,Yu Chao Autophagy Zinc oxide nanoparticles (ZnONPs) hold great promise for biomedical applications. Previous studies have revealed that ZnONPs exposure can induce toxicity in endothelial cells, but the underlying mechanisms have not been fully elucidated. In this study, we report that ZnONPs can induce ferroptosis of both HUVECs and EA.hy926 cells, as evidenced by the elevation of intracellular iron levels, lipid peroxidation and cell death in a dose- and time-dependent manner. In addition, both the lipid reactive oxygen species (ROS) scavenger ferrostatin-1 and the iron chelator deferiprone attenuated ZnONPs-induced cell death. Intriguingly, we found that ZnONPs-induced ferroptosis is macroautophagy/autophagy-dependent, because the inhibition of autophagy with a pharmacological inhibitor or by gene knockout profoundly mitigated ZnONPs-induced ferroptosis. We further demonstrated that NCOA4 (nuclear receptor coactivator 4)-mediated ferritinophagy (autophagic degradation of the major intracellular iron storage protein ferritin) was required for the ferroptosis induced by ZnONPs, by showing that knockdown can reduce the intracellular iron level and lipid peroxidation, and subsequently alleviate ZnONPs-induced cell death. Furthermore, we showed that ROS originating from mitochondria (mtROS) probably activated the AMPK-ULK1 axis to trigger ferritinophagy. Most importantly, pulmonary ZnONPs exposure caused vascular inflammation and ferritinophagy in mice, and ferrostatin-1 supplementation significantly reversed the vascular injury induced by pulmonary ZnONPs exposure. Overall, our study indicates that ferroptosis is a novel mechanism for ZnONPs-induced endothelial cytotoxicity, and that NCOA4-mediated ferritinophagy is required for ZnONPs-induced ferroptotic cell death. 3-MA: 3-methyladenine; ACTB: Actin beta; AMPK: AMP-activated protein kinase; ATG: Autophagy-related; BafA1: Bafilomycin A1; CQ: Choloroquine; DFP: Deferiprone; FACS: Fluorescence-activated cell sorting; Fer-1: Ferrostatin-1; FTH1: Ferritin heavy chain 1; GPX4: Glutathione peroxidase 4; GSH: Glutathione; IREB2/IRP2: Iron responsive element binding protein 2; LIP: Labile iron pool; MAP1LC3B/LC3B: Microtubule associated protein 1 light chain 3 beta; MTOR: Mechanistic target of rapamycin kinase; NCOA4: Nuclear receptor coactivator 4; NFE2L2/NRF2: Nuclear factor, erythroid 2 like 2; PGSK: Phen Green™ SK; ROS: Reactive oxygen species; siRNA: Small interfering RNA; SQSTM1/p62: Sequestosome 1; TEM: Transmission electron microscopy; ULK1: Unc-51 like autophagy activating kinase 1; ZnONPs: Zinc oxide nanoparticles. 10.1080/15548627.2021.1911016