Cardiac microRNAs: diagnostic and therapeutic potential

MicroRNAs are small non-coding post-translational biomolecules which, when expressed, modify their target genes. It is estimated that microRNAs regulate production of approximately 60% of all human proteins and enzymes that are responsible for major physiological processes. In cardiovascular disease pathophysiology, there are several cells that produce microRNAs, including endothelial cells, vascular smooth muscle cells, macrophages, platelets, and cardiomyocytes. There is a constant crosstalk between microRNAs derived from various cell sources. Atherosclerosis initiation and progression are driven by many pro-inflammatory and pro-thrombotic microRNAs. Atherosclerotic plaque rupture is the leading cause of cardiovascular death resulting from acute coronary syndrome (ACS) and leads to cardiac remodeling and fibrosis following ACS. MicroRNAs are powerful modulators of plaque progression and transformation into a vulnerable state, which can eventually lead to plaque rupture. There is a growing body of evidence which demonstrates that following ACS, microRNAs might inhibit fibroblast proliferation and scarring, as well as harmful apoptosis of cardiomyocytes, and stimulate fibroblast reprogramming into induced cardiac progenitor cells. In this review, we focus on the role of cardiomyocyte-derived and cardiac fibroblast-derived microRNAs that are involved in the regulation of genes associated with cardiomyocyte and fibroblast function and in atherosclerosis-related cardiac ischemia. Understanding their mechanisms may lead to the development of microRNA cocktails that can potentially be used in regenerative cardiology.