观察炎症状态和高脂状态对mTOR/S6K/IRS1-Ser和IRS1-Tyr信号通路表达的影响  

Effects of inflammatory condition and high fat diet toward mTOR/S6K/IRS1-Ser and IRS1-Tyr signaling pathways

作　　者：王尧[1] 万立华[1] 蒋朴[1] 袁增琼[1] 

机构地区：[1]重庆医科大学基础医学院法医学教研室,400016

出　　处：《免疫学杂志》2012年第6期497-501,共5页Immunological Journal

摘　　要：目的观察在体内外炎症状态下哺乳动物雷帕霉素靶蛋白(mTOR)-70S核糖体蛋白S6激酶(S6K)-胰岛素受体底物1(IRS1)信号传导通路异常磷酸化表达对胰岛素抵抗的影响。方法体外实验,将HepG2分为4组:对照组、高脂组[给予100 mg/L低密度脂蛋白(LDL)处理]、炎症介入组[给予20μg/L肿瘤坏死因子-α(TNF-α)处理]、联合干预组(给予20μg/L TNF-α+100 mg/L LDL处理)。采用实时定量PCR和Western blotting方法检测mTOR、S6K和IRS1 mRNA及蛋白表达水平;体内实验,8周龄c57BL/6J小鼠随机分为4组(正常饮食组、正常饮食加炎症组、高脂饮食组和高脂饮食加炎症组),分别给予隔日皮下注射生理盐水和酪蛋白建立炎症模型,8周后将实验小鼠于深度麻醉下处死并检测其肝脏组织中mTOR、S6K和IRS1 mRNA及蛋白表达水平。结果体内外实验均显示与对照组相比,炎症组与高脂组mTOR、S6K和IRS1-Ser mRNA及蛋白表达增加,而联合干预组表达明显增高,IRS1-Tyr mRNA及蛋白表达下降,联合干预组表达明显降低。结论炎症及高脂状态激活mTOR/s6k/IRS1-Ser信号通路,而抑制IRS1-Tyr信号通路,从而加重胰岛素抵抗。This study aimed to observe the influence of mammalian target of rapamycin protein （mTOR）-70S ribosomal protein kinase ‘S6＇ （S6K）-insulin receptor substratel （IRS1） signaling pathway on insulin resistance in vivo and in vitro under inflammatory conditions. For in vitro experiments, HepG2 were cultured and divided into control group （incubated with serum free medium）, high lipid group （treated with serum free medium plus low density lipoprotein （LDL, 100 mg/L）, inflammatory stress group （treated with tumor necrosis factor-α （TNF-α 20 μg/L）, and combination treatment group （treated with TNF-α （20 μg/L） plus LDL （100 mg/L）. For in vivo experiments, c57BL/6J mice aged 8 weeks were randomly divided into four groups （normal diet group, normal diet and inflammation group, high fat diet group, and high fat diet plus inflammation group）, and the inflammation model was established with subcutaneous injection of casein. Eight weeks later, mice were sacrificed by deep anesthesia, and the mRNA and protein expression level of mTOR, S6K, and IRS1 in mouse liver tissue were examined by real-time polymerase chain reaction （PCR） and Western blotting. Experiments all showed that LDL and TNF-α increased the expression levels of mTOR, S6K and plRSl-ser mRNA and protein HepG2s compared with the control group. Furthermore, in inflammation and high fat group, the expression levels of mTOR, S6K and IRS1 mRNA and protein increased also, and the joint intervention group showed more obvious increase. All result indicated that high fat diet and inflammatory state could activate mTOR/s61dlRS1 signaling pathways, and inhibit insulin normal signal pathway, thus results in insulin resistance.

关 键 词：炎症状态 MTOR信号通路 胰岛素受体底物1 胰岛素抵抗 

分 类 号：R363[医药卫生—病理学]