Vascular calcification in atherosclerosis: potential roles of macrophages and non-coding micro-RNAs

Abstract

Coronary heart disease, a leading cause of death in western societies, is caused by the presence of atherosclerotic plaques in the coronary arteries. Calcification is a frequent complication of atherosclerotic plaques, and often a contributing factor to their instability and rupture. Endothelial cells, smooth muscle cells and plaque macrophages, all contribute to the calcification process, which is reminiscent of that underlying bone formation. In particular, the role of macrophages in calcification has long been recognized, but whether or not distinct macrophage subsets v.g., M1 or inflammatory, and M2 or anti-inflammatory- have specific functions in osteogenic signaling within the context of plaque calcification remains poorly understood. Over the past few years, accumulated evidence has revealed novel roles of non-coding micro-RNAs (miRs) in atherorelevant functions of macrophages and in mechanisms linked to macrophage divergence into different subtypes. In this article we discuss some salient findings on potential roles of miRs in vascular calcification, with focus on those miRs that have also been associated to macrophage differentiation, and speculate on their potential relation to M1 and M2 macrophages in the context of calcification of atherosclerotic plaques.