Ferritinophagy-mediated ferroptosis is involved in sepsis-induced cardiac injury.

Ferroptosis is a reactive oxygen species (ROS)- and iron-dependent form of regulated cell death (RCD), playing critical roles in organ injury and targeting therapy of cancers. Previous studies have demonstrated that ferroptosis participates in the development of cardiomyopathy including cardiac hypertrophy, diabetic cardiomyopathy and doxorubicin-induced cardiotoxicity. However, the role of ferroptosis in sepsis-induced cardiac injury remains unclear. This study aimed to explore the role and underlying mechanism of ferroptosis on lipopolysaccharide (LPS)-induced cardiac injury. Mice were injected with LPS (10 mg/kg) for 12 h to generate experimental sepsis. Ferrostatin-1 (Fer-1) and Dexrazoxane (DXZ) were used to suppress ferroptosis of mice with sepsis-induced cardiac injury. LPS increased the levels of ferroptotic markers involving prostaglandin endoperoxide synthase 2 (PTGS2), malonaldehyde (MDA) and lipid ROS, apart from resulting in obvious mitochondria damage, which were alleviated by Fer-1 and DXZ. In vitro experiments showed that Fer-1 inhibited LPS-induced lipid peroxidation and injury of H9c2 myofibroblasts while erastin and sorafenib aggravated LPS-induced ferroptosis. Additionally, Fer-1 and DXZ improved survival rate and cardiac function of mice with sepsis. Mechanistically, LPS increased the expression of nuclear receptor coactivator 4 (NCOA4) and the level of intracellular Fe2+ but decreased the level of ferritin. NCOA4 could directly interact with ferritin and degrade it in a ferritinophagy-dependent manner, which subsequently released a great amount of iron. Cytoplasmic Fe2+ further activated the expression of siderofexin (SFXN1) on mitochondrial membrane, which in turn transported cytoplasmic Fe2+ into mitochondria, giving rise to the production of mitochondrial ROS and ferroptosis. Based on these findings, we concluded that ferritinophagy-mediated ferroptosis is one of the critical mechanisms contributing to sepsis-induced cardiac injury. Targeting ferroptosis in cardiomyocytes may be a therapeutic strategy for preventing sepsis in the future.

Li N ，Wang W ，Zhou H ，Wu Q ，Duan M ，Liu C ，Wu H ，Deng W ，Shen D ，Tang Q ... -  《-》

STAT3 signaling promotes cardiac injury by upregulating NCOA4-mediated ferritinophagy and ferroptosis in high-fat-diet fed mice.

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.

Zhu M ，Peng L ，Huo S ，Peng D ，Gou J ，Shi W ，Tao J ，Jiang T ，Jiang Y ，Wang Q ，Huang B ，Men L ，Li S ，Lv J ，Lin L ... -  《-》

TMEM43 Protects against Sepsis-Induced Cardiac Injury via Inhibiting Ferroptosis in Mice.

Chen Z ，Cao Z ，Gui F ，Zhang M ，Wu X ，Peng H ，Yu B ，Li W ，Ai F ，Zhang J ... -  《Cells》

Alleviated NCOA4-mediated ferritinophagy protected RA FLSs from ferroptosis in lipopolysaccharide-induced inflammation under hypoxia.

Wang Y ，Ding H ，Zheng Y ，Wei X ，Yang X ，Wei H ，Tian Y ，Sun X ，Wei W ，Ma J ，Tian D ，Zheng F ... -  《-》

Ferritinophagy is involved in the zinc oxide nanoparticles-induced ferroptosis of vascular endothelial cells.

Qin X ，Zhang J ，Wang B ，Xu G ，Yang X ，Zou Z ，Yu C ... -  《-》