Plasma extracellular vesicle modulate immune cell transcriptional responses following acute myocardial infarction.

Plasma extracellular vesicles (EVs) increase during acute myocardial infarction (MI), correlate with myocardial injury, and mobilize immune cells from the spleen to the circulation. These cells are transcriptionally activated even before tissue recruitment, yet the mechanisms driving this priming are unclear. We show that plasma EVs isolated at hospital presentation with MI are enriched in miRNA-320b. Endothelial cells upregulate miRNA-320b in EVs following inflammatory stimulation. Target gene pathway analysis revealed enrichment in adhesion and cytokine signaling. Endothelial EVs promoted monocyte adhesion and induced IL6 and TNF mRNA expression in macrophages while dampening cytokine secretion. RNA-sequencing of MI patient neutrophils and monocytes confirmed significant enrichment of miRNA-320b targets. Peripheral blood mononuclear cells treated with MI plasma EVs showed similar gene regulation. These findings suggest that EV-mediated transfer of miRNA-320b primes immune cells for adhesion and cytokine signaling. Understanding this signaling axis may enable therapeutic immunomodulation of immune cells to improve repair following MI.