罗格列酮对人脐静脉内皮细胞NO和PI3K/PKB/eNOS信号通路的影响

目的:观察罗格列酮对人脐静脉内皮细胞(human umbilical vein endothelial cells,HUVEC)一氧化氮(nitric oxide,NO)浓度和内皮型一氧化氮合酶(endothelial nitric oxide synthase,eNOS)、磷脂酰肌醇-3激酶(phosphatidylinositol 3-kinase,PI3K)和蛋白激酶B(protein kinase B,PKB)表达的影响,探讨罗格列酮改善内皮功能的信号转导机制.方法:首先观察罗格列酮对内皮细胞NO影响的时效和量效关系,然后加用eNOS和PKB信号阻断剂进行干预.用Griess重氮化反应法检测NO浓度,RT-PCR方法检测PI3K,PKB及eNOSmRNA的表达,Western免疫印迹方法检测PKB,eNOS总蛋白和PKB丝氨酸473(PKB-Ser473),eNOS丝氨酸1177(eNOS-Ser1177)的磷酸化表达.结果:罗格列酮呈剂量和时间依赖性地升高内皮细胞NO浓度,不同浓度的罗格列酮培养内皮细胞均能升高PI3K mRNA表达和PKB-Ser473,eNOS-Ser1177磷酸化,但对PKB和eNOS表达均无影响;eNOS阻断剂L-NAME能完全阻断罗格列酮培养的内皮细胞NO浓度的升高,PI3K阻断剂LY294002能阻断罗格列酮诱导的NO产生和PKB,eNOS的磷酸化.结论:罗格列酮能通过激活PI3K/PKB/eNOS信号通路而增强内皮细胞NO的浓度,改善内皮功能.

Effect of rosiglitazone on NO and eNOS via PI3K/PKB signalpathways in cultured human umbilical vein endothelial cells

Objective To observe the effect of rosiglitazone on the production of nitric oxide (NO) and the expression of phosphatidylinositol 3-kinase (PI3K)/protein kinase B(PKB) /the endothelial nitric oxide synthase (eNOS) in cultured human umbilical vein endothelial cells(HUVECs), and to investigate the mechanism of signal transduction of rosiglitazone in improving the endothelial function.Methods HUVECs were treated with various concentrations of rosiglitazone. The NO level was measured using Griess Reaction in cell culture supernatants; the expressions of PI3K-,PKB- and eNOS mRNA were measured using RT-PCR; and the expresstions of PKB, eNOS, and phosphorylation of PKB-Ser473, eNOS-Ser1177 were measured using Western Blot. Results Rosiglitazone increased the endothelial NO production in a dose- and time-dependent manner in cultured HUVECs, and also increased the expression of PI3K mRNA and the phosphorylation of PKB-Ser473 and eNOS-Ser1177 in a concentration-dependent manner, with no alteration in the expression of PKB and eNOS in cultured HUVECs. N(w)-nitro-L- arginine methyl ester (L-NAME, eNOS synthase inhibitor) blocked the rosiglitazone-induced NO formation; LY294002(a PI3K inhibitor) prevented the NO production; and the phosphorylation of eNOS and PKB was induced by rosiglitazone. Conclusion Treatment with rosiglitazone can increase the NO prouducion and improve the endothelial function through up-regulating the PI3K/PKB/eNOS signal pathways in cultured HUVECs.