Caveolae在高糖诱导的大鼠肾小球系膜细胞细胞外基质合成中的作用

Role of caveolae in high glucose-induced extracellular matrix production in rat mesangial cells

目的:探讨胞膜小凹(caveolae)在高糖(HG)诱导大鼠肾小球系膜细胞(MCs)细胞外基质(extra-cellular matrix,ECM)表达过程中的作用。方法:传代培养的大鼠MCs同步化后分为:(1)正常糖组;(2)HG组;(3)HG+甲基-β-环糊精(β-MCD)组;(4)HG+β-MCD+胆固醇组。用Western blotting检测小凹蛋白1(Cav-1)、磷酸化小凹蛋白1(p-Cav-1-Y14)和Ⅰ型胶原(ColⅠ)蛋白的表达水平,用实时定量PCR检测细胞中Cav-1 mRNA表达变化,用ELISA方法检测上清中纤维连接蛋白(FN)的蛋白含量。结果:(1)高糖状态下,系膜细胞FN和ColⅠ蛋白表达水平均显著增加(均P<0.05)。(2)高糖培养显著增加p-Cav-1-Y14水平(P<0.01),而对Cav-1 mRNA及蛋白表达无明显影响(P>0.05)。(3)β-MCD预处理抑制了高糖诱导的p-Cav-1-Y14升高(P<0.01)及FN表达(P<0.05),但对高糖诱导的Col I表达无影响;β-MCD的作用可被胆固醇抑制。结论:高糖可显著增加系膜细胞1型胶原及纤维连接蛋白的合成。高糖诱导的纤维连接蛋白合成与Cav-1磷酸化水平增加有关。

AIM： To investigate the role of caveolae in high glucose （HG）-induced extracellular matrix （ECM） production in rat mesangial cells （MCs）. METHODS： Synchronized rat MCs were divided into normal glucose group, HG group, HG ＋ methyl-13-cyclodextrin （13-MCD） group and HG ＋ 13-MCD ＋ cholesterol （Chol） group. Western blotting was used to detect the protein expression of caveolin-1 （ Car-1 ）, phosphorylated caveolin-1 （p-Cav-l-Yl4） and collagen type 1 （Col I）. The mRNA expression of Cav-I was determined by real-time PCR. ELISA was used to measure the level of fibronectin （FN） in the supernatant. RESULTS： High glucose significantly increased the expression of FN and Col I. In HG 12, 24 and 48 h groups, the mRNA and protein levels of Car-1 were not significantly different from those in HG 0 h group, whereas the level of p-Car-l-Y14 was significantly increased. 13-MCD significantly attenuated HG-induced elevation of p-Cav-l-Y14 and FN production, but had no effect on HG-induced Col I expression. All these responses to 13- MCD were abolished by Chol. CONCLUSION ： High glucose significantly increases the production of Col I and FN in rat MCs. FN production induced by high glucose is mediated by p-Cav-l-Yl4.