重组人胰高糖素样多肽-1(rhGLP-1)对人肝细胞系HL-7702胰岛素信号通路的影响

Effect of rhGLP-1 on insulin signalling pathway in human hepatocytes

目的通过研究重组人胰高糖素样多肽-1(rh GLP-1)对人肝细胞系HL-7702胰岛素信号通路关键位点Akt表达的影响,揭示GLP-1对肝细胞胰岛素信号通路PI3K-AKT-m TORC的作用。方法选用处于对数生长期的人肝细胞系HL-7702,分别在含有不同浓度rh GLP-1(7-36)(10 n M、100 n M、1000 n M)的培养液中培养24 h,以空白培养液作为对照。用蛋白质免疫印迹法(western blot)检测Akt蛋白及磷酸化Akt(p-Akt)蛋白的表达量。结果 Akt蛋白的表达水平在对照组与GLP-1低浓度组、GLP-1中浓度组、GLP-1高浓度组均无明显差异。与对照组相比,p-Akt(Thr308)的表达量在GLP-1低浓度组(0.60±0.27 vs 1±0,P<0.05)、GLP-1中浓度组(0.61±0.18 vs 1±0,P<0.05)、GLP-1高浓度组(0.54±0.15 vs 1±0,P<0.01)明显下降;p-Akt(Ser473)的表达量在对照组与GLP-1不同浓度组之间均没有差异。结论 GLP-1导致人肝细胞p-Akt的表达水平下降,提示GLP-1对肝细胞PI3K-AKT-m TORC通路可能具有抑制作用,这可能是GLP-1类降糖药物降低血脂的机制之一。

Objective To investigate the effect of rhGLP-1 on the expression of Akt,a key site of insulin signalling pathway in human hepatocyte line（HL-7702）,in order to explore the mechanism by which rhGLP-1 regulates insulin signal pathway PI3K-AKTm TORC in hepatocytes.Methods HL-7702 cells in the logarithmic growth phase were selected and divided into three treatment groups and one control group.The three treatment groups were respectively treated with different concentrations of rhGLP-1（7-36）（10,100,1000 nM） for 24 hours,while the control group was cultured for 24 hours with an equal amount of medium.The expression of Akt protein and its phosphorylation level were detected by Western blot.Results The expression of Akt did not change significantly in any group.so were the levels of phosphorylation of Akt（Ser473）.The levels of phosphorylation of Akt（Thr308） in 10 nM treatment group（0.60 ± 0.27 vs 1 ± 0,P〈0.05）,in 100 nM treatment group（0.54 ± 0.15 vs 1 ± 0,P〈0.01）,and in 1000 n M treatment group（0.61 ± 0.18 vs 1 ± 0,P〈0.05） were all significantly lower than that in the control group.Conclusions The decrease of the expression of phosphorylated Akt in rhGLP-1 treated HL-7702 cells indicates that GLP-1 may have inhibitory effect on PI3 K-AKT-m TORC pathway,which may be one of the mechanisms by which GLP-1 reduces blood lipids.