Lipotoxicity induces cardiomyocyte ferroptosis via activating the STING pathway

Objective Lipotoxicity is a well-established contributor to cardiomyocyte death and heart damage, with ferroptosis being identified as a crucial death mode in cardiomyocyte disease. This study aims to explore the potential role and mechanism of ferroptosis in lipotoxicity-induced myocardial injury. Methods Eight-weeks high-fat diet (HFD) SD rat and H9c2 cardiomyocytes treated with palmitic acid (PA) were established for in vivo and in vitro lipotoxic model. Ferrostatin-1 (Fer-1) and liproxstatin-1 (Lip-1) were used to inhibit ferroptosis. Myocardial-specific STING knockdown rat (Stingmyo-KD) with HFD was further introduced. Rat cardiac structure and function, cell viability, the level of lipid peroxidation, malondialdehyde (MDA), glutathione (GSH), mitochondrial function, ferroptosis related proteins and STING pathway related proteins in H9c2 cells/myocardium were detected. Results HFD rats with ferroptosis inhibitor showed improved cardiac structure and function, reduced lipid peroxidation and restored GSH, which was further confirmed in H9c2 cell. The time-dependent activation of the STING pathway following PA stimulation was observed. Knockdown the expression of STING could reduce PA-induced cell death, lipid peroxidation and MDA levels while restoring the GSH. In addition, both HFD Stingmyo-KD rats and HFD rats with systematic inhibited by STING inhibitor exhibited mitigating lipotoxicity-induced myocardial ferroptosis and reducing myocardial injury. Innovation and conclusion These findings suggest that lipotoxicity can induce ferroptosis in cardiomyocytes through the activation of the STING pathway, providing new targets, and strategies for the treatment of lipotoxicity cardiomyopathy.