Oxidized phosphatidylcholines trigger ferroptosis in cardiomyocytes during ischemia/reperfusion injury.

Myocardial ischemia/reperfusion (I/R) injury increases the generation of oxidized phosphatidylcholines (OxPCs) which results in cell death. However, the mechanism by which OxPCs mediate cell death is largely unknown. The aim of this study was to determine the mechanisms by which OxPC triggers cardiomyocyte cell death during reperfusion injury. Cardiomyocyte viability, bioenergetic response and calcium transients were determined in the presence of OxPCs. Fragmented OxPCs resulted in a decrease in cell viability with POVPC and PONPC having the most potent cardiotoxic effect in both a concentration and time dependent manner (P<0.05). POVPC and PONPC also caused a significant decrease in Ca2+ transients and net contraction in isolated cardiomyocytes compared to vehicle treated control cells (P<0.05). PONPC depressed maximal respiration rate (p<0.01; 54%) and spare respiratory capacity (p<0.01; 54.5%). Notably, neither caspase 3 activation or TUNEL staining was observed in cells treated with either POVPC or PONPC. Further, cardiac myocytes treated with OxPCs were indistinguishable from vehicle treated control cells with respect to nuclear HMGB1 activity. Glutathione peroxidase 4 activity was markedly suppressed in cardiomyocytes treated with POVPC and PONPC. Importantly, cell death induced by OxPCs could be suppressed E06 Ab, directed against OxPCs or by ferrostatin. The findings of the present study suggest that OxPCs disrupt mitochondrial bioenergetics, calcium transients and provoke wide spread cell death through ferroptosis during I/R. Neutralization of OxPC with E06 or with ferrostatin-1 prevents cell death during reperfusion. Our study demonstrates a novel signaling pathway that operationally links generation of OxPC during cardiac I/R to ferroptosis.