Wnt/β-catenin信号途径在高糖诱导肾小管上皮细胞转分化中的作用

ROLE OF WNT/β-CATENIN SIGNALING PATHWAY IN TUBULAR EPITHELIAL-MESENCHYMAL TRANSITION INDUCED BY HIGH GLUCOSE

目的探讨Wnt/β-catenin信号途径在高糖诱导肾小管上皮细胞转分化中的作用。方法体外培养人近端肾小管上皮细胞(HKC),分为正常糖组、甘露醇对照组及高糖组。采用免疫细胞化学观察β-连环蛋白(β-catenin)表达情况;Westernblot检测Wnt4、β-catenin、E-钙粘蛋白(E-cadherin)和α-平滑肌肌动蛋白(α-SMA)表达水平;逆转录-聚合酶链反应检测Wnt4和β-cateninmRNA表达水平。结果高糖组较正常糖及渗透浓度对照组Wnt4蛋白及mRNA、α-SMA蛋白表达增高,E-cadherin表达降低,β-catenin总蛋白及mRNA水平无明显变化,细胞浆及核内蛋白表达增强。高糖刺激肾小管上皮细胞Wnt4及核β-catenin蛋白表达呈时间依赖性,于高糖刺激后12h增强,24h达到高峰。结论Wnt/β-catenin信号通路可能参与了高糖介导的肾小管上皮细胞转分化过程。

Objective To investigate the expression of the Wnt/13-catenin signaling pathway in tubular epithelial-mesenchymal transition （EMT） induced by high-glucose. Methods Human kidney proximal tubular epithelial cells （HKCs） cultured in vitro were divided into three groups at random： normal-glucose group, mannitol control group and high-glucose group. Immunocytochemistry was used to observe the expression of β-catenin. The protein expressions of the Wnt4, β-catenin, E-cadherin and α-SMA were assessed by Western blot. Wnt4 and β-eatenin mRNA were detected by reverse transcription polymerase chain reaction （RT-PCR） . Results Compared with those of normal-glucose and mannitol control groups, both the protein and the mRNA expressions of Wnt4 were up-regulated in HKCs stimulated by high-glucose. The expression of α-SMA significantly increased but E-Cadherin decreased in the high-glucose group. There were no difference in total protein and mRNA of β-catenin, but its nuclear and cytoplasmic fractions were up-regulated in the high-glucose group. Nuclear transloeation of β-catenin in HKCs was time-dependent, being significant at 12h and peaking at 24h. Conclusion These data support a functional role of the Wnt/β-catenin signaling pathway during epithelial-mesenchymal transition of HKCs induced by high glucose.