Transcription factors targeted by miRNAs regulating smooth muscle cell growth and intimal thickening after vascular injury

Abstract

Neointima formation after percutaneous coronary intervention (PCI) is a manifestation of “phenotype switching” by vascular smooth muscle cells (SMC), a process that involves de-differentiation from a contractile quiescent phenotype to one that is richly synthetic. In response to injury, SMCs migrate, proliferate, down‐regulate SMC‐specific differentiation genes, and later, can revert to the contractile phenotype. The vascular response to injury is regulated by microRNAs (or miRNAs), small non‐coding RNAs that control gene expression. Interactions between miRNAs and transcription factors impact gene regulatory networks. This article briefly reviews the roles of a range of miRNAs in molecular and cellular processes that control intimal thickening, focusing mainly on transcription factors, some of which are encoded by immediate‐early genes. Examples include Egr‐1, junB, KLF4, KLF5, Elk‐1, Ets‐1, HMGB1, Smad1, Smad3, FoxO4, SRF, Rb, Sp1 and c‐ Myb. Such mechanistic information could inform the development of strategies that block SMC growth, neointima formation, and potentially overcome limitations of lasting efficacy following PCI.