14,15-EET mitigates sepsis-induced cardiomyopathy by inhibiting cardiomyocyte ferroptosis via PPARα activation.

Abstract

BACKGROUND: Ferroptosis has emerged as a central driver of sepsis-induced cardiomyopathy. Epoxyeicosatrienoic acids (EETs) possess cardioprotective properties, but whether 14,15-EET confers protection in septic cardiomyopathy remains unclear. This study investigated the effect and mechanism of 14,15-EET on sepsis-induced cardiomyopathy. MATERIALS AND METHODS: To establish models of sepsis, septic mice were induced by cecal ligation and puncture (CLP), whereas H9C2 cardiomyocytes were treated with lipopolysaccharide (LPS) to mimic sepsis in vitro. Echocardiography was used to assess cardiac function by measuring ejection fraction (EF) and fractional shortening (FS). ELISA assays measured serum levels of creatine kinase-MB (CK-MB) and cardiac troponin I (cTnI). Lipid metabolomics was performed using ultra-performance liquid chromatography-tandem mass spectrometry (UPLC-MS/MS)-based lipidomics. Network pharmacology and molecular docking were applied to identify potential targets linking 14,15-EET, ferroptosis, and sepsis-induced cardiomyopathy. Biochemical assays were performed to quantify myocardial ferrous iron (Fe), reduced glutathione (GSH), and malondialdehyde (MDA). Reactive oxygen species (ROS) were visualized using fluorescence-based probes in H9C2 cells and dihydroethidium in heart sections. Western blotting quantified GPX4, xCT, and PPARα expression. RESULTS: 14,15-EET was markedly reduced in the myocardium of septic mice, as revealed by lipidomics. Network pharmacology and molecular docking identified PPARα as a central target mediating the anti-ferroptotic effects of 14,15-EET during sepsis. In LPS-stimulated cardiomyocytes, 14,15-EET inhibited ferroptosis by lowering intracellular Fe, MDA, and ROS levels, while restoring GSH and upregulating xCT and GPX4 expression. Stabilization of 14,15-EET through TPPU, a soluble epoxide hydrolase (sEH) inhibitor, attenuated myocardial ferroptosis and concurrently conferred cardioprotection in septic mice by improving EF and FS and lowering serum levels of creatine kinase-MB and cTnI. Notably, 14,15-EET upregulated PPARα expression in both septic myocardium and cardiomyocytes, whereas pharmacological inhibition with GW6471 abolished its anti-ferroptotic and cardioprotective actions. CONCLUSIONS: 14,15-EET attenuates sepsis-induced cardiomyopathy by suppressing ferroptosis through PPARα activation.