Caveolin-1与葡萄糖转运蛋白4共同参与PC12细胞缺糖应激调节(英文)

Caveolin-1 and glucose transporter 4 involved in the regulation of glucosedeprivation stress in PC12 cells

近年研究表明,作为构成胞膜窖(Caveolae)主要的组分之一,窖蛋白-1(caveolin-1,Cav-1)除了在细胞胆固醇平衡、信号转导和整合以及细胞生长等过程中起重要作用外,还参与细胞营养改变的神经元代谢调节过程。本文旨在探讨Cav-1和葡萄糖转运蛋白4(glucose transporter 4,GLUT4)在神经细胞内营养环境改变时的功能变化和关系。采用Western blot和激光共聚焦法观察了两种蛋白在PC12细胞葡萄糖剥夺(glucose deprivation,GD)前后的表达水平与分布,发现GD 6 h后能诱导PC12细胞内Cav-1和GLUT4蛋白表达水平增加,CCK检测和流式细胞术结果显示细胞活力下降、细胞内钙离子浓度([Ca2+]i)升高、线粒体膜电位(mitochondrial membrane potential,MMP)下降。采用si RNA技术敲低Cav-1基因后,GD组PC12细胞死亡率和[Ca2+]i进一步升高,MMP进一步下降;Cav-1敲低细胞系和甲基化β环化糊精(methylated-β-Cyclodextrin,M-β-CD)法处理实验组中,Cav-1和GLUT4蛋白表达均下降。此外还发现,GD可促进GLUT4从细胞质转位到细胞膜。结果提示,Cav-1可能通过调节GLUT4在GD情况下发挥神经保护作用。

Recent evidence suggests that caveolin-1 （Cav-1）, the major protein constituent of caveolae, plays a prominent role in neuronal nutritional availability with cellular fate regulation besides in several cellular processes such as cholesterol homeostasis, regulation of signal transduction, integrin signaling and cell growth. Here, we aimed to investigate the function of Cav-1 and glucose transporter 4 （GLUT4） upon glucose deprivation （GD） in PC12 cells. The results demonstrated firstly that both Cav-1 and GLUT4 were up-regulated by glucose withdrawal in PC12 cells by using Western blot and laser confocal technology. Also, we found that the cell death rate, mitochondrial membrane potential （MMP） and intracellular free Ca^2＋ concentration （[Ca^2＋]i） were also respectively changed followed the GD stress tested by CCK8 and flow cytometry. After knocking down of Cav-1 in the cells by siRNA, the level of [Ca^2＋]i was increased, and MMP was reduced further in GD-treated PC12 cells. Knockdown of Cav-1 or methylated-β-Cyclodextrin （M-β-CD） treatment inhibited the expression of GLUT4 protein upon GD. Additionally, we found that GLUT4 could translocate from cytoplasm to cell membrane upon GD. These findings might suggest a neuroprotective role for Cav-1, through coordination of GLUT4 in GD.