LAUSR

OBJECTIVE Sepsis can induce myocardial dysfunctions and endothelial progenitor cells (EPCs)-derived extracellular vesicles (EVs) can attenuate sepsis. Concerning to that, this article is intended to decode whether microRNA (miR)-375-3p in EPCs-EVs could affect myocardial injury in sepsis. METHODS Rat bone marrow-derived EPCs and EPCs-EVs were harvested. A rat model of sepsis was established by cecal ligation and puncture. Septic rats were injected with EPCs-EVs that interfered with miR-375-3p, after which cardiac function, inflammatory response, pathological damage, oxidative stress and apoptosis were detected in myocardial tissues. miR-375-3p, bromodomain 4 (BRD4), phosphoinositide 3-kinase (PI3K) and protein kinase B (AKT) expression in myocardial tissues, and their reciprocals were identified. RESULTS Septic rats expressed reduced miR-375-3p and elevated BRD4 in myocardial tissues. EPCs-EVs improved cardiac function, suppressed inflammation, oxidative stress and apoptosis, as well as attenuated the pathological damage of myocardial tissues in septic rats. Up-regulated/down-regulated miR-375-3p in EPCs-EVs relieved/deteriorated myocardial injury in septic rats. miR-375-3p targeted BRD4 to activate PI3K/AKT pathway, thereafter to ameliorate myocardial injury in septic rats. CONCLUSION It is illustrated that miR-375-3p in EPCs-EVs activates BRD4-mediated PI3K/AKT signaling pathway to ameliorate myocardial injury in septic rats, which provides a therapeutic target for myocardial injury in sepsis.