Fei Xu1, Abu Shufian Ishtiaq Ahmed1, Xiuhua Kang1, Guoqing Hu1, Fang Liu1, Wei Zhang1, Jiliang Zhou2. 1. From the Department of Respiratory Medicine, The First Affiliated Hospital of Nanchang University, Nanchang, China (F.X., X.K., W.Z.); and Department of Pharmacology and Toxicology, Medical College of Georgia, Georgia Regents University, Augusta (A.S.I.A., X.K., G.H., F.L., J.Z.). 2. From the Department of Respiratory Medicine, The First Affiliated Hospital of Nanchang University, Nanchang, China (F.X., X.K., W.Z.); and Department of Pharmacology and Toxicology, Medical College of Georgia, Georgia Regents University, Augusta (A.S.I.A., X.K., G.H., F.L., J.Z.). jizhou@gru.edu.
Abstract
OBJECTIVE: To investigate the functional role of the microRNA (miR)-15b/16 in vascular smooth muscle (SM) phenotypic modulation. APPROACH AND RESULTS: We found that miR-15b/16 is one of the most abundant mRs expressed in contractile vascular smooth muscle cells (VSMCs). However, when contractile VSMCs get converted to a synthetic phenotype, miR-15b/16 expression is significantly reduced. Knocking down endogenous miR-15b/16 in VSMCs attenuates SM-specific gene expression but promotes VSMC proliferation and migration. Conversely, overexpression of miR-15b/16 promotes SM contractile gene expression while attenuating VSMC migration and proliferation. Consistent with this, overexpression of miR-15b/16 in a rat carotid balloon injury model markedly attenuates injury-induced SM dedifferentiation and neointima formation. Mechanistically, we identified the potent oncoprotein yes-associated protein (YAP) as a downstream target of miR-15b/16 in VSMCs. Reporter assays validated that miR-15b/16 targets YAP's 3' untranslated region. Moreover, overexpression of miR-15b/16 significantly represses YAP expression, whereas conversely, depletion of endogenous miR-15b/16 results in upregulation of YAP expression. CONCLUSIONS: These results indicate that miR-15b/16 plays a critical role in SM phenotypic modulation at least partly through targeting YAP. Restoring expression of miR-15b/16 would be a potential therapeutic approach for treatment of proliferative vascular diseases.
OBJECTIVE: To investigate the functional role of the microRNA (miR)-15b/16 in vascular smooth muscle (SM) phenotypic modulation. APPROACH AND RESULTS: We found that miR-15b/16 is one of the most abundant mRs expressed in contractile vascular smooth muscle cells (VSMCs). However, when contractile VSMCs get converted to a synthetic phenotype, miR-15b/16 expression is significantly reduced. Knocking down endogenous miR-15b/16 in VSMCs attenuates SM-specific gene expression but promotes VSMC proliferation and migration. Conversely, overexpression of miR-15b/16 promotes SM contractile gene expression while attenuating VSMC migration and proliferation. Consistent with this, overexpression of miR-15b/16 in a rat carotid balloon injury model markedly attenuates injury-induced SM dedifferentiation and neointima formation. Mechanistically, we identified the potent oncoprotein yes-associated protein (YAP) as a downstream target of miR-15b/16 in VSMCs. Reporter assays validated that miR-15b/16 targets YAP's 3' untranslated region. Moreover, overexpression of miR-15b/16 significantly represses YAP expression, whereas conversely, depletion of endogenous miR-15b/16 results in upregulation of YAP expression. CONCLUSIONS: These results indicate that miR-15b/16 plays a critical role in SM phenotypic modulation at least partly through targeting YAP. Restoring expression of miR-15b/16 would be a potential therapeutic approach for treatment of proliferative vascular diseases.