胰岛素受体底物蛋白1及其丝氨酸磷酸化活性在胰岛素抵抗发生中的作用

The study of the role of IRS1 and its serine phosphorylation activity in pathogenesis of insulin resistance

目的探讨胰岛素受体底物蛋白1(IRS1)及其丝氨酸磷酸化在胰岛素抵抗(IR)发生中的作用。方法 C57BL/6小鼠40只随机分为正常饮食组(NC组)和高脂饮食组(HF组),HC组喂养高脂饮食16周后建立IR模型。16周后处死,检测空腹血清胰岛素和口服糖耐量;RT-PCR检测小鼠骨骼肌TSC2和IRS1mRNA表达。Western blot和免疫荧光染色检测骨骼肌TSC2、IRS1、IRS1Ser307和IRS1Ser636/639蛋白表达。结果与NF组相比,HC组小鼠空腹血清胰岛素显著升高(P<0.01),糖耐量显著受损,骨骼肌细胞TSC2mRNA和蛋白均显著降低(P<0.05),HF组pIRS1Ser307和pIRS1Ser636/639蛋白表达显著增加(P<0.01)。结论高脂饮食可能通过抑制TSC2基因和蛋白表达,增强IRS1Ser307和IRS1Ser636/639的磷酸化水平,阻碍胰岛素信号传导,诱发IR。

Objective To investigate the effects of insulin receptor substrate 1（IRS1） and activity of IRS1 serine phosphorylation on the development of insulin resistant. Methods 20 male C57BL/6 mice were divided into normal diet group（NC） and high fat diet group（HF） and all mice showed insulin resistance.The mice in HF were fed with high fat diet for 16 weeks.Serum insulin concentration was also evaluated by ELISA.RT-PCR,Western blot and immunofluorescence were performed to detect TSC2 and IRS1 mRNA and protein expression in skeletal muscle. Results As compared with NC group,HF group showed that fasting insulin value was increased（P〈0.01）,OGTT was damaged,mRNA and protein expressions of TSC2 of skeletal muscle of mice were decreased（P〈0.05）,and the expression of pIRS1Ser307 and pIRS1Ser636/639 was increased（P〈0.01）.Conclusions High-fat diet possibly produces IR by inhibiting TSC2 mRNA and protein expression,and by increasing IRS1Ser307 and IRS1Ser636/639 phosphorylation levels in mice skeletal muscle.