目的    观察甲状旁腺激素（PTH）对人肾小管上皮细胞（HK-2）间充质转分化的影响，探讨Wnt信号通路在其中的作用。 方法    细胞被分为对照组和PTH处理组。实时定量-聚合酶链反应（RT-PCR）和Western印迹法检测α平滑肌肌动蛋白（α-SMA）及钙黏素E（E-cadherin） mRNA及蛋白的表达；10^-10 mol/L PTH 作用细胞48 h后，采用实时定量PCR芯片技术检测Wnt通路相关基因表达。不同浓度PTH作用后和10^-10 mol/L PTH作用不同时间后， 用RT-PCR、Western印迹法检测Wnt4 mRNA及蛋白的表达。构建Wnt4过表达及敲除Wnt4的细胞模型，用RT-PCR、Western 印迹法检测α-SMA、E-cadherin 、Wnt4 mRNA及蛋白质表达。 结果    与PTH处理组相比，PTH+DKK1组α-SMA mRNA和蛋白表达量明显降低；E-cadherin mRNA及蛋白表达量明显升高（均P＜0.01）。PTH处理组细胞有18个Wnt信号通路基因显著上调和9个基因下调；与对照组相比，PTH处理组细胞Wnt4 mRNA和蛋白表达量明显增加（均P＜0.01）；与PTH处理组相比，PTH+Wnt4过表达组α-SMA mRNA和蛋白表达量明显上调， E-cadherin mRNA和蛋白表达量明显下调（均P＜0.05）。与PTH处理组相比，PTH+Wnt4 siRNA组α-SMA mRNA和蛋白表达量降低，E-cadherin mRNA和蛋白相对表达量升高（均P＜0.05）。 结论    甲状旁腺激素诱导HK-2细胞间充质转分化。其机制可能与PTH激活Wnt信号通路，尤其Wnt4信号通路有关。

Objective    To observe the effect of parathyroid hormone on transdifferentiation of human renal proximal tubular epithelial cell (HK-2), and to investigate the role of Wnt signaling pathway in this process.    Methods    The expression of α-SMA, E-cadherin mRNA and protein was detected by real-time PCR and Western blotting. After the induction of 10^-10 mol/L PTH for 48 h, the Wnt pathway associated gene expression profiling was detected by quantitative PCR-microarray. The expression of Wnt4 mRNA and protein under various concentrations of PTH or after exposed to 10^-10 mol/L PTH for different time was detected by real-time PCR and Western blotting. The overexpression and knock-down plasmids of Wnt4 were constructed and the expression of α-SMA, E-cadherin, Wnt4 mRNA and protein was detected by real-time PCR and western blotting after overexpression and knockdown of Wnt4.    Results    Compared with PTH group, the expression of α-SMA mRNA and protein in PTH+DKK1 group was significantly down-regulated, while E-cadherin mRNA and protein expression was significantly up-regulated (all P＜0.01). PTH treatment resulted in the up-regulation of 18 genes and down-regulation of 9 genes associated with Wnt pathway. Compared with control group, the expression of Wnt4 mRNA and protein increased markedly in PTH group (all P＜0.01). The expression of α-SMA mRNA and protein was significantly up-regulated and E-cadherin mRNA and protein expression was significantly down-regulated after overexpression of Wnt4 and PTH treatment (all P＜0.05), while the expression of α-SMA mRNA and protein was significantly down-regulted and E-cadherin mRNA and protein expression was significantly down-regulated after knockdown of Wnt4 and PTH treatment (all P＜0.05).    Conclusions    PTH-induced EMT in HK-2 cells is mediated by Wnt signal pathway, and Wnt4 might be a key gene during PTH-induced EMT.