P13K/Akt信号通路在白蛋白诱导肾小管上皮细胞转化生长因子β1表达中的作用

目的 研究白蛋白对人肾小管上皮细胞(HK-2)分泌转化生长因子β1(TGF-β1)的影响,以及P13K/Akt信号通路在这一过程中的作用.方法 体外培养HK-2细胞,分为对照组、白蛋白(BSA)组和白蛋白加抑制剂(BSA+Ly294002)组.分别于培养12、24、48 h后,用MTT法检测HK-2细胞的增殖;RT-PCR检测HK-2细胞TGF-β1 mRNA的表达;Western印迹测定HK-2细胞TGF-β1和磷酸化的PI3K(p-PI3K)、Akt(p-Akt)蛋白分泌.结果 白蛋白可明显诱导HK-2细胞增殖(P<0.05),诱导后12 hBSA组与对照组比较,TGF-β1 mRNA表达明显上调(0.472±0.025比0.233±0.021,P<0.05);TGF-β1蛋白明显上调(296±20.1比100±13.2,P<0.05);p-PI3K、p-Akt蛋白表达显著增加(P<0.05).加Ly294002 12 h时HK-2增殖受抑制;48 h时TGF-β1 mRNA、蛋白和p-PI3K、P-Akt蛋白的表达也受到抑制(均为P<0.05).结论 白蛋白通过活化PI3-K/Akt信号转导通路诱导肾小管上皮细胞产生TGF-β1.

Effect of PI3K/ Akt signal pathway on albumin- induced transforming growth factor beta 1 expression in renal tubular epithelial cells

Objective To investigate the role of PI3K/Akt signal pathway in albumin-induced transforming growth factor beta 1 (TGF-β1) expression and proliferation in renal proximal tubule cells (HK-2).Methods HK-2 cells were cultured in vitro and allocated to three groups: control, albumin(BSA) and BSA+ Ly294002 (PI3K/Akt specific inhibitor).Cell proliferation was assessed by MTT method.TGF-β1 mRNA expression was determined by RT-PCR and protein outputs from TGF-β1, phosphorylated PI3K (p-PI3K) and Akt (p-Akt) was measured by Western blotting at 12, 24 and 48 h of culture.Results MTT revealed that higher dosage of BSA (30 mg/ml) overload induced significant proliferation in HK-2 cells (P< 0.05).Compared with control group, remarkable increase or up-regnlation was shown in expression of TGF-β 1 mRNA (0.472±0.025 vs 0.233±0.021, P<0.05), protein output from TGF-β1 (296±20.1 vs 100±13.2, P<0.05), p-PI3K (P<0.05) and p-Akt (P<0.05), with BSA induction at 12.Addition of Ly294002 was demonstrated to inhibit HK-2 proliferation at 12 hours and protein expressions in TGF-β1, p-PI3K and p-Akt at 48 h (P<0.05).Conclusion Albumin may induce TGF-β1 production through the activation of PI3-K/Akt signal pathway in renal tubular epithelial cells.