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目的:葡萄糖转运体4(GLUT4)在球囊损伤血管新生内膜中高表达,而其转位过程依赖于肌动蛋白(actin)细胞骨架的调节。平滑肌蛋白22α(smooth muscle protein 22α,SM22α)是一种actin细胞骨架相关蛋白,其在增殖性血管疾病中表达下调。本研究观察了SM22α是否参与血管损伤或者PDGF刺激诱导的GLUT4表达和转位活性升高。方法:用PDGF-BB刺激血管平滑肌细胞(vascular smooth muscle cell,VSMC),观察GLUT4膜转位和细胞骨架的变化;用荧光葡萄糖2-NBDG检测葡萄糖摄取;用特异性si RNA敲低内源性SM22α表达;Brd U实验检测细胞增殖;高效液相色谱法检测组织葡萄糖含量。结果:PDGFBB诱导VSMCs GLUT4转位和葡萄糖摄取依赖于皮层F-actin聚合,而敲低SM22α促进这一过程。损伤新生内膜处GLUT4表达显著增加,PDGF-BB刺激促进细胞GLUT4表达和葡萄糖消耗,抑制GLUT4活性则显著降低细胞增殖活性。相对于WT组,SM22α-/-小鼠颈总动脉2-NBDG摄取显著增加,结扎后28 d新生内膜明显增厚,损伤动脉组织GLTU4转位和葡萄糖含量均明显升高。结论:PDGF-BB诱导的GLUT4转位和糖摄取参与VSMCs增殖。缺失SM22α可诱导皮层细胞骨架聚合,增强PDGF-BB诱导的GLUT4膜转位和糖摄取及代谢活性。SM22α是一种新的增殖相关糖代谢调节因子。
OBJECTIVE: Glucose transporter 4 (GLUT4) is highly expressed in the neointima of balloon-injured vessels and its translocation depends on the regulation of the actin cytoskeleton. Smooth muscle protein 22α (SM22α) is an actin cytoskeleton related protein that is down-regulated in proliferative vascular diseases. This study looked at whether SM22α is involved in vascular injury or PDGF stimulation-induced increase in GLUT4 expression and translocation activity. Methods: The vascular smooth muscle cell (VSMC) was stimulated with PDGF-BB to observe the translocation of GLUT4 membrane and the change of cytoskeleton. Glucose uptake was detected by fluorescent glucose 2-NBDG. Endogenous SM22α expression; BrdU test to detect cell proliferation; high-performance liquid chromatography detection of tissue glucose content. RESULTS: PDGFBB induced GLUT4 translocation and glucose uptake in VSMCs dependent on cortical F-actin polymerization, while knockdown of SM22α promoted this process. Injury of neointima at the GLUT4 expression was significantly increased, PDGF-BB stimulation of cell GLUT4 expression and glucose consumption, inhibition of GLUT4 activity was significantly reduced cell proliferation activity. Compared with the WT group, the uptake of 2-NBDG in the common carotid artery of SM22α - / - mice was significantly increased, and the neointimal thickness was significantly increased at 28 days after ligation. GLTU4 translocation and glucose content were significantly increased in injured arteries. CONCLUSION: PDGF-BB-induced GLUT4 translocation and glucose uptake are involved in the proliferation of VSMCs. Deletion of SM22α induced cortical cytoskeletal polymerization and enhanced PDGF-BB-induced GLUT4 membrane translocation and glucose uptake and metabolic activity. SM22α is a novel regulator of proliferation-related glycometabolism.