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PPARγ对TGFβ/smad信号通路阻遏子c-Ski的上调作用

李工博, 李军, 曾益军, 钟丹, 吴庚泽, 付晓红, 何凤田, 戴双双^*

第三军医大学 基础部生物化学与分子生物学教研室；西南医院胸心外科，重庆 400038

摘要

本文旨在研究过氧化物酶体增殖物激活受体γ (peroxisome proliferator-activated receptor γ, PPARγ)对动脉粥样硬化(atherosclerosis, AS)形成中关键信号通路TGFβ/smad途径的阻遏子c-Ski的调控作用，探讨PPARγ抗AS的分子机制。通过高脂饮食制作大鼠AS模型，检测AS斑块中c-Ski的mRNA及蛋白的表达变化；在体外培养的大鼠血管平滑肌细胞(vascular smooth muscle cell, VSMC)中转染重组c-Ski质粒，并观察其对VSMC增殖及胶原分泌影响；采用real-time PCR和Western blot检测PPARγ激动剂和拮抗剂对c-Ski表达的调节，进而利用在线程序NUBIScan及荧光素酶报告基因检测明确PPARγ对c-Ski的调控机理。结果显示：AS大鼠动脉斑块中c-Ski mRNA和蛋白表达显著降低；重组c-Ski转染显著抑制大鼠VSMC增殖及胶原分泌；PPARγ激动剂罗格列酮可明显上调大鼠VSMC中c-Ski表达，且这种上调可以被PPARγ拮抗剂GW9662所阻断。生物信息学分析表明c-Ski启动子区有可能的PPARγ结合位点，而罗格列酮也能显著上调转染了c-Ski的报告基因表达。以上结果表明c-Ski具有一定抗AS作用，其可能是PPARγ的又一靶基因，激活PPARγ可上调c-Ski而发挥抗AS作用。

关键词： 氧化物酶体增殖物激活受体γ; c-Ski; 动脉粥样硬化; 血管平滑肌细胞

分类号：R329

[PPARγ up-regulates TGFβ/smad signal pathway repressor c-Ski.] [Article in Chinese]

LI Gong-Bo, LI Jun, ZENG Yi-Jun, ZHONG Dan, WU Geng-Ze, FU Xiao-Hong, HE Feng-Tian, DAI Shuang-Shuang^*

Department of Biochemistry and Molecular Biology； Department of Cardiothoracic Surgery, Southwest Hospital, Third Military Medical University, Chongqing 400038, China

Abstract

TGFβ/smad pathway is recognized as an important signal pathway to promote the pathogenesis of atherosclerosis (AS). Peroxisome proliferator-activated receptor γ (PPARγ) activation is considered to be important in modulating AS. Herein, we investigated the regulation of PPARγ on c-Ski, the repressor of TGFβ/smad pathway, in rat AS model and cultured vascular smooth muscle cells (VSMCs). c-Ski mRNA and protein expression were detected by real-time PCR and Western blot, respectively, in vivo and in vitro with treatment of PPARγ agonist rosiglitazone and antagonist GW9662. The proliferation and collagen secretion of VSMCs after c-Ski transfection were investigated. The underlying mechanism was further investigated by online program NUBIScan and luciferase reporter gene analysis. Results showed that both mRNA and protein expressions of c-Ski in the AS lesions was down-regulated in vivo, while in cultured VSMCs, c-Ski transfection significantly suppressed the proliferation and collagen secretion of rat VSMCs. Rosiglitazone significantly up-regulated mRNA and protein levels of c-Ski in VSMCs, which could be blocked by GW9662. Online NUBIScan analysis suggested possible PPARγ binding sites in the promoter region of c-Ski. In addition, luciferase activity of c-Ski reporter gene was also increased obviously in the presence of rosiglitazone. These results indicate that c-Ski is one of the newly found target genes of PPARγ and thus involved in the anti-AS effect of PPARγ.

Key words: peroxisome proliferator-activated receptor γ; c-Ski; atherosclerosis; Vascular smooth muscle cell

收稿日期：2010-10-29　　录用日期：2010-12-15

通讯作者：戴双双　　E-mail: tmmubiodss@yahoo.com.cn

引用本文：

李工博, 李军, 曾益军, 钟丹, 吴庚泽, 付晓红, 何凤田, 戴双双. PPARγ对TGFβ/smad信号通路阻遏子c-Ski的上调作用[J]. 生理学报 2011; 63 (1): 62-68.

LI Gong-Bo, LI Jun, ZENG Yi-Jun, ZHONG Dan, WU Geng-Ze, FU Xiao-Hong, HE Feng-Tian, DAI Shuang-Shuang. [PPARγ up-regulates TGFβ/smad signal pathway repressor c-Ski.] [Article in Chinese]. Acta Physiol Sin 2011; 63 (1): 62-68 (in Chinese with English abstract).