Role of specific microRNAs in regulation of vascular smooth muscle cell differentiation and the response to injury.

Vascular smooth muscle cells (VSMCs) exhibit remarkable plasticity during postnatal development. Vascular injury initiates and perpetuates VSMCs dedifferentiation to a synthetic phenotype, which has been increasingly recognized to play a central role in neointimal hyperplasia during the pathogenesis of vascular proliferative diseases. MicroRNAs (miRNAs) are a novel class of regulatory noncoding RNAs that regulate gene expression at the posttranscriptional level by binding to 3' untranslated regions of target mRNAs, leading to either degrading mRNAs or inhibiting their translation. There is emerging evidence that miRNAs are critical regulators of widespread cellular functions such as differentiation, proliferation, and migration. Recent studies have indicated that a number of specific miRNAs play important roles in regulation of vascular cell functions and contribute to neointimal hyperplasia after vascular injury. Here, we review recent advance regarding functions of specific miRNAs in vasculature and discuss possible mechanisms by which miRNAs modulate proliferation and differentiation of VSMCs.