PI3K/Akt信号通路对肺泡上皮钠通道α亚基表达的影响

Effect of PI3K/Akt signaling pathway on the expression of epithelial sodium channelαsubunit

目的探讨磷酯酰肌醇3-激酶/蛋白激酶B(PI3K/Akt)信号通路对肺泡上皮钠通道α亚基(α-ENaC)表达的影响。方法体外培养肺泡上皮细胞A549,以不同浓度(2、20、200 mU/L)及不同作用时间(30、60、120 min)的胰岛素和Akt抑制剂LY294002干预。反转录-PCR测定α-ENaC mRNA,蛋白质印迹法测定α-ENaC蛋白和磷酸化(p-Akt)的表达。结果α-ENaC mRNA和蛋白表达水平随胰岛素浓度增加而增加,与对照组比较,差异有统计学意义(P<0.05);p-Akt水平也同步增加。α-ENaC mRNA和蛋白表达水平随胰岛素作用时间延长而增加,与对照组比较,差异有统计学意义(P<0.05);p-Akt水平也同步增加。LY294002作用后,α-ENaC mRNA、蛋白及p-Akt水平均下降(P<0.05)。结论激活PI3K/Akt通路能上调α-ENaC mRNA和蛋白表达水平,有益于肺水肿液清除。

Objective To investigate the effect of phosphatidylinositol 3-kinase/protein kinase B(PI3K/Akt)signaling pathway on the expression of epithelial sodium channelαsubunit(α-ENaC)in A549 cells.Methods Alveolar epithelial cells,A549 cells,were incubated with 2,20 and 200 mU/L insulin for 120 min or 200 mU/L insulin for 30,60 and 120 min or Akt inhibitor(LY294002),respectively.The expression levels ofα-ENaC mRNA and protein and p-Akt level were determined by using RT-PCR and Western blot.Results The expression levels of mRNA and protein ofα-ENaC elevated with the increase of insulin concentration,compared with those in the control group,the differences were statistically significant(P<0.05).And the level of p-Akt increased consistently.The expression levels of mRNA and protein ofα-ENaC increased with the prolongation of insulin treatment,compared with those in the control group,the differences were statistically significant(P<0.05).And the level of p-Akt increased consistently.After treatment with LY294002,the expression levels of mRNA and protein ofα-ENaC and p-Akt level decreased significantly(P<0.05).Conclusion Activation of PI3K/Akt signaling pathway up-regulates the expression of mRNA and protein ofα-ENaC,which is beneficial for pulmonary edema clearance.