Implication of miR-155-5p and miR-143-3p in the Vascular Insulin Resistance and Instability of Human and Experimental Atherosclerotic Plaque.

(1) Background: Cardiovascular diseases (CVDs) are the main cause of death in developed countries, being atherosclerosis, a recurring process underlying their apparition. MicroRNAs (miRNAs) modulate the expression of their targets and have emerged as key players in CVDs; (2) Methods: 18 miRNAs were selected (Pubmed and GEO database) for their possible role in promoting atherosclerosis and were analysed by RT-qPCR in the aorta from apolipoprotein E-deficient () mice. Afterwards, the altered miRNAs in the aorta from 18 weeks- mice were studied in human aortic and carotid samples; (3) Results: miR-155-5p was overexpressed and miR-143-3p was downregulated in mouse and human atherosclerotic lesions. In addition, a significant decrease in protein kinase B (AKT), target of miR-155-5p, and an increase in insulin-like growth factor type II receptor (IGF-IIR), target of miR-143-3p, were noted in aortic roots from mice and in carotid plaques from patients with advanced carotid atherosclerosis (ACA). Finally, the overexpression of miR-155-5p reduced AKT levels and its phosphorylation in vascular smooth muscle cells, while miR-143-3p overexpression decreased IGF-IIR reducing apoptosis in vascular cells; (4) Conclusions: Our results suggest that miR-155-5p and miR-143-3p may be implicated in insulin resistance and plaque instability by the modulation of their targets AKT and IGF-IIR, contributing to the progression of atherosclerosis.