Vascular Endothelial Cell-Derived Exosomal Sphingosylphosphorylcholine Attenuates Myocardial Ischemia-Reperfusion Injury through NR4A2-Mediated Mitophagy.

Cardiomyocyte survival is a critical contributing process of host adaptive responses to cardiovascular diseases (CVD). Cells of the cardiovascular endothelium have recently been reported to promote cardiomyocyte survival through exosome-loading cargos. Sphingosylphosphorylcholine (SPC), an intermediate metabolite of sphingolipids, mediates protection against myocardial infarction (MI). Nevertheless, the mechanism of SPC delivery by vascular endothelial cell (VEC)-derived exosomes (VEC-Exos) remains uncharacterized at the time of this writing. The present study utilized a mice model of ischemia/reperfusion (I/R) to demonstrate that the administration of exosomes via tail vein injection significantly diminished the severity of I/R-induced cardiac damage and prevented apoptosis of cardiomyocytes. Moreover, SPC was here identified as the primary mediator of the observed protective effects of VEC-Exos. In addition, within this investigation, in vitro experiments using cardiomyocytes showed that SPC counteracted myocardial I/R injury by activating the Parkin and nuclear receptor subfamily group A member 2/optineurin (NR4A2/OPTN) pathways, in turn resulting in increased levels of mitophagy within I/R-affected myocardium. The present study highlights the potential therapeutic effects of SPC-rich exosomes secreted by VECs on alleviating I/R-induced apoptosis in cardiomyocytes, thereby providing strong experimental evidence to support the application of SPC as a potential therapeutic target in the prevention and treatment of myocardial infarction.