Enhancer of polycomb1 lessens neointima formation by potentiation of myocardin-induced smooth muscle differentiation

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• 作者：Hosouk Joung^a ; Jin-Sook Kwon^b ; Ju-Ryoung Kim^c ; Sera Shin^a ; Wanseok Kang^b ; Youngkeun Ahn^b ; Hyun Kook^a ; ^b ; ^{kookhyun@chonnam.ac.kr} ; Hae Jin Kee^a ; ^b ; ^{sshjkee@empas.com}
• 关键词：Enhancer of polycomb1 (Epc1) ; Serum response factor (SRF) ; Myocardin (Myocd) ; Vascular smooth muscle cell differentiation ; Neointimal formation
• 刊名：Atherosclerosis
• 出版年：2012
• 期刊代码：28_00219150
• 类别：med
• 出版时间：May, 2012
• 卷：222
• 期：1
• 页码：84-91
• 文件大小：1144 K

摘要

Objective

Previously, we reported that enhancer of polycomb1 (Epc1) induces skeletal muscle differentiation through the serum response factor (SRF). Considering that SRF plays a critical role in vascular smooth muscle cell (VSMC) differentiation, we expected that Epc1 also works in VSMCs. Here we examined the effect of Epc1 on neointima formation after arterial balloon injury and the underlying mechanism.

Methods

Epc1 expression was examined in carotid artery injury or VSMC models. Interaction with myocardin (Myocd), a master regulator of smooth muscle differentiation, was examined by immunoprecipitation or promoter analysis with smooth muscle (SM) 22伪 promoter. Finally, we investigated whether local delivery of Epc1 regulated neointimal formation after injury.

Results

Epc1 expression was down-regulated during proliferation induced by platelet-derived growth factor BB, whereas it was upregulated during differentiation in VSMCs. Forced expression of Epc1 induced VSMC differentiation. Epc1 physically interacted with Myocd to synergistically activate SM22伪 promoter activity. Transient transfection of Epc1 enhanced the physical interaction between Myocd and SRF, whereas that interaction was reduced when A10 cells were treated with siRNA for Epc1. Local delivery of Epc1 significantly reduced neointima formation induced by balloon injury.

Conclusions

Our results indicate that Epc1 induces VSMC differentiation by interacting with Myocd to induce SRF-dependent smooth muscle genes. We propose that Epc1 acts as a novel negative regulator of neointima formation after carotid injury.