心肌素在周期性张应变调控血管平滑肌细胞表型转化中的作用  

Role of myocardin in the regulation of phenotypic transformation of vascular smooth muscle cell by cyclic stretch

作　　者：潘敏熇 郑熙隆[2] 廖端芳[1] PAN Minhe;ZHENG Xilong;LIAO Duanfang(School of Pharmacy,Hunan University of Traditional Chinese Medicine,Changsha,Hunan 410208,China;College of Chinese and Western Combination,Hunan University of Traditional Chinese Medicine,Changsha,Hunan 410208,China)

机构地区：[1]湖南中医药大学药学院,湖南省长沙市410208 [2]湖南中医药大学中西结合学院,湖南省长沙市410208

出　　处：《中国动脉硬化杂志》2020年第9期749-756,共8页Chinese Journal of Arteriosclerosis

基　　金：国家自然科学基金项目(81773736)。

摘　　要：目的探讨周期性张应变条件下诱导血管平滑肌细胞(VSMC)表型转换时,心肌素在其中可能的作用。方法应用FX-5000T体外周期性张应变加载系统,分别对体外培养的VSMC施加频率为1.25 Hz、加载幅度为5%(正常张应变状态)、15%(高张应变状态)的周期性张应变力学刺激,加载时间为24 h。采用蛋白免疫印迹法和实时荧光定量PCR技术检测心肌素、肌肉萎缩相关基因1(atrogin-1)及相关收缩蛋白SMA、SM22的蛋白表达水平和mRNA水平;敲除atrogin-1后测心肌素及相关收缩蛋白SMA、SM22的变化;用蛋白酶体抑制剂MG132处理后测心肌素和atrogin-1的表达水平。结果与5%正常张应变组比较,15%高张应变促进平滑肌细胞的去分化。15%高张应变下调心肌素和SMA、SM22蛋白水平;上调atrogin-1蛋白表达水平;下调心肌素和SMA、SM22的mRNA水平,上调atrogin-1 mRNA水平。应用siRNA特异性下调atrogin-1后,心肌素、SMA、SM22蛋白水平均上升。用1μmol/L MG132处理细胞后,心肌素、SMA、SM22的蛋白水平上升,atrogin-1蛋白水平下降。结论周期性高张应变可以通过调节血管平滑肌细胞中atrogin-1/心肌素轴来调控血管平滑肌表型转换,进而影响VSMC的分化增殖。Aim To investigate the possible role of myocardin in the vascular remodeling of vascular smooth muscle cell(VSMC)induced by high cyclic tensile stress.Methods Using FX-5000T in vitro cyclic stretch loading system,the VSMC in vitro were stimulated by cyclic stretch with frequency of 1.25 Hz,loading amplitude of 5%(normal physiological state)and 15%(simulated hypertension state)for 24 hours;Western blot and real time RT-PCR were used to detect the protein expression level and mRNA level of myocardin,atrogin-1,SMA and SM22.The expression level of myocardin and atrogin-1 were measured after the treatment with proteasome inhibitor MG132.The alteration of myocardin,SMA and SM22 was measured after the knockdown of atrogin-1.Results Compared with 5%normal group,15%cyclic stretch promoted the dedifferentiation of SMCs.Western blot showed that 15%of cyclic stretch decreased the protein le-vels of myocardin,SMA and SM22,and increased the protein expression level of atrogin-1.RTPCR showed that the mRNA levels of myocardin,SMA and SM22 were down regulated,and the mRNA level of atrogin-1 was up regulated.The results showed that the protein levels of myocardin,SMA and SM22 increased after siRNA downregulation of atrogin-1.The protein levels of myocardin,SMA and SM22 increased and the protein level of atrogin-1 de-creased after treated with 1μmol/L MG132.Conclusion High cyclic stretch can regulate phenotypic transformation of VSMC by regulating the expression of myocardin,an important transcription co-factor,thus affecting the differentiation and proliferation of VSMC.

关 键 词：周期性张应变 血管平滑肌细胞 心肌素 肌肉萎缩相关基因1 泛素蛋白酶体降解 

分 类 号：R54[医药卫生—心血管疾病]