肽基脯氨酰异构酶Pin1在动脉粥样硬化的血管平滑肌细胞衰老中的作用

The role of Pin1 in the senescence of atherosclerotic vascular smooth muscle cells

目的探讨肽基脯氨酰异构酶(Pin1)调节动脉粥样硬化及血管平滑肌细胞(VSMCs)衰老的机制。方法收集正常及动脉粥样硬化病变的股动脉组织标本,并分别对其原代培养得到正常及动脉粥样硬化的VSMCs。运用免疫组化技术分别检测人体正常和动脉粥样硬化的股动脉组织中Pin1的表达;运用改良的TRAP法分别检测正常和动脉粥样硬化病变的股动脉组织中VSMCs的衰老情况;运用蛋白质印迹分析法检测VSMCs和过表达Pin1的动脉粥样硬化VSMCs中p Rb通路以及cyclin通路关键蛋白的表达。结果与正常情况相比,动脉粥样硬化股动脉组织中Pin1蛋白表达明显下调(P <0.05);动脉粥样硬化的VSMCs端粒酶活性被抑制(P <0.05);动脉粥样硬化的VSMCs中p-pRb的蛋白表达水平增加(P <0.05),Pin1及细胞周期蛋白B、D和E的表达水平明显下调(P <0.05)。反之,腺病毒介导的Pin1过表达下调p-pRb(P <0.05),上调细胞周期蛋白B、D和E(P <0.05)。结论 Pin1通过影响pRb通路以及cyclin通路调控VSMCs衰老,是VSMCs衰老调节机制中的关键因子,同时可能提供了一个调控动脉粥样硬化病理过程的新靶点。

Objective To investigate the mechanism underlying Pin1 in regulating atherosclerosis and senescence of vascular smooth muscle cells(VSMCs).Methods The normal and atherosclerotic femoral arterial tissue samples were collected.The normal and atherosclerotic VSMCs were primarily cultured from two kinds of femoral arterial tissue,separately.Immunohistochemistry assay was used to detect the expression of Pin1 in human atherosclerotic femoral arterial tissue.The modified TRAP assay was used to detect the senescence of VSMCs in normal and atherosclerotic femoral artery tissue.Western blot assay was used to detect some key protein expression in pathways,such as pRb pathway and cyclin pathway,in VSMCs and atherosclerotic VSMCs with Pin1 overexpression.Results Compared with the normal condition,the expression of Pin1 protein was significantly down-regulated in atherosclerotic femoral artery tissue(P<0.05).The telomerase activity in atherosclerotic VSMCs was also inhibited(P<0.05).The expression of p-pRb in atherosclerotic VSMCs was increased(P<0.05)and the protein expression of Pin1,cell cycle proteins B,D,and E was significantly down-regulated(P<0.05).Conversely,adenovirus-mediated Pin1 overexpression inhibited the level of p-pRb(P<0.05)and increase the expression of cyclin B,D,and E(P<0.05).Conclusion Pin1 regulates the senescence of VSMCs through affecting pRb pathway and cyclin pathway,providing a new target for the regulation of the pathological process of atherosclerosis.