ω-6 PUFA-enriched membrane phospholipid composition of cardiomyocytes increases the susceptibility to iron-induced ferroptosis and inflammation

Abstract

Ferroptosis is an attractive therapeutic target in cardiometabolic disease (CMD); however, its contribution to myocardial damage requires further elucidation. This study was designed to examine whether altered phospholipid composition in cardiomyocytes enhanced ferroptosis susceptibility, and the underlying mechanisms. Human iPSC-derived cardiomyocytes and H9c2 cells were used to study iron-induced lipid peroxidation, cell death, and inflammation after exposure to different types of fatty acids. Lipidomic analysis was performed using LC/MS to assess changes in phospholipid composition, with a focus on ω-6 PUFA-containing phospholipids. Cellular and mitochondrial lipid peroxidation, sterile inflammation, and cell death were evaluated. Additionally, the release of damage-associated molecular patterns (DAMPs) and macrophage responses, including STING and type I interferon (IFN-I) signaling, were investigated. LC/MS lipidomic analysis indicated that treating cells with arachidonic acid (AA) elevated ω-6 PUFA-containing phospholipids, particularly phosphatidylethanolamines (PE) and phosphatidylcholines (PC). This significantly increased susceptibility to iron-induced total cellular as well as mitochondrial lipid peroxidation. Subsequently, increased release of mitochondrial DNA to cytosol was detected, resulting in both sterile inflammation and subsequent cell death. Furthermore, iron-induced release of one or more damage associated molecular patterns (DAMP) from AA-treated cells that induced crosstalk with macrophages eliciting a STING and type I interferon (IFN-I) response. These results indicate that cardiomyocytes enriched with ω-6 PUFA-containing phospholipids are more susceptible to lipid peroxidation, underscoring ferroptosis as a critical factor in myocardial damage associated with CMD.

Keywords: Ferroptosis; Lipid peroxidation; Mitochondrial DNA; PUFA-containing phospholipids; Sterile inflammation.