miR-186-5p Dysregulation in Serum Exosomes from Patients with AMI Aggravates Atherosclerosis via Targeting LOX-1

PURPOSE: The formation of macrophage-derived foam cells via the uptake of modified lipoproteins is a pivotal development event in atherosclerosis. It has been reported that clinical and experimental myocardial infarction could accelerate atherosclerosis. Several studies have suggested the critical role of exosomes in cardiovascular diseases. However, the role of exosomes from patients with acute myocardial infarction (AMI) patients in atherogenesis remains unclear. PATIENTS AND METHODS: Serum exosomes from AMI patients (AMI-Exo) and control individuals (Con-Exo) were isolated and characterized. These exosomes were studied in vitro and in vivo to determine their impact on macrophage foaming and atherogenesis. RESULTS: Our results showed that AMI-Exo promoted foam cell formation in oxidized low-density lipoprotein (ox-LDL)-treated macrophages and progression of atherosclerosis in high-fat/cholesterol diet-fed ApoE(−/−) mice together with a significantly upregulated levels of lectin-like ox-LDL receptor-1 (LOX-1). The miR-186-5p was found to be downregulated in AMI-Exo and macrophages administered with AMI-Exo. Moreover, serum exosomal miR-186-5p achieved high diagnostic performance for AMI. Luciferase reporter assay indicated that miR-186-5p directly inhibited LOX-1. The endogenous or exogenous miR-186-5p deficiency enhanced lipid accumulation by upregulating LOX-1, whereas miR-186-5p mimics had a reverse effect. CONCLUSION: In conclusion, the current findings suggest that dysregulated miR-186-5p in AMI-Exo may explain the contribution of acute ischemia events to the advancement of atherosclerosis by enhancing macrophage foaming via its target, LOX-1.