miR-142-3p Is a Regulator of the TGFβ-Mediated Vascular Smooth Muscle Cell Phenotype

The transforming growth factor β (TGFβ) signaling pathway is critical for the promotion and maintenance of the contractile phenotype of vascular smooth muscle cells (VSMCs). Though multiple microRNAs (miRNAs) implicated in the regulation of the VSMC phenotype have been identified, the modulation of miRNAs in the VSMCs by TGFβ signaling has not been fully described. In this study, we identified microRNA-142-3p (miR-142-3p) as a modulator of the VSMC phenotype in response to TGFβ signaling. We show that miR-142-3p is induced upon TGFβ signaling, leading to the repression of a novel target, dedicator of cytokinesis 6 (DOCK6). The downregulation of DOCK6 by miR-142-3p is critical for cell migration. Thus, this study demonstrates that miR-142-3p is a key regulator of the TGFβ-mediated contractile phenotype of VSMCs that acts through inhibiting cell migration through targeting DOCK6.