姜黄素对肾小管上皮细胞转分化smad信号转导途径的影响

目的 探讨姜黄素(Cur)对转化生长因子-β1(TGF-β1)诱导的肾小管上皮细胞转分化(EMT)smad信号转导途径的干预作用.方法 以10 μg/L的TGF-β1作用人近端肾小管上皮细胞(HK-2)不同的时间(0、12、24、48和72h),以Western印迹方法检测α平滑肌肌动蛋白(α-SMA)、钙黏蛋白(E-cadherin)的表达.用递增浓度的Cur(1、5、10μmoL/L)预处理HK-2细胞24 h, 加入含TGF-β1(10 μg/L)培养液继续培养细胞48h后,收获细胞提取蛋白和mRNA,以Western印迹方法检测smad3、p-smad2/3、smad7、TFβR-II的表达;以RT-PCR方法检测ColⅠ、ColⅢmRNA的表达.结果 TGF-β1诱导HK-2细胞内smad2/3磷酸化的现象,既早于E-cadherin蛋白的下调,更先于新蛋白α-SMA的合成;姜黄素干预后,可明显抑制TFβR-II蛋白的表达、smad2蛋白磷酸化及ColⅠ、ColⅢmRNA的表达,增强抑制因子smad7的表达.结论 姜黄素可干预TGF-β1 /smads信号转导途径的多个位点,从而阻断EMT过程.

Influence of curcumin on smad signal transduction pathway of EMT*

Objective To investigate the interfering effect of curcumin (Cur) on smad signal transduction pathway of epithelial myofibroblast transdifferentiation ( EMT) induced by transforming growth factor-β1 (TGF-β1). Methods The human HK-2 cells were treated by TGF-β1 (10 μg/L) at different time points (0, 12, 24, 48 and 72 h). The expressions of α-smooth muscle actin (α-SMA) and E-cadherin were detected by using Western blotting method. The human HK-2 cells were pretreated with Cur in ascending concentration (1,5 and 10 μmoL/L) for 24 hours and then cultured in TGF-β1 culture solution for collecting and exacting protein and mRNA for 48 hours. The expressions of smad3, p-smad2/3, smad7 and TFpR- Ⅱ were detected by using Western blotting method, and mRNA expressions of collagen Ⅰ (Col Ⅰ ) and Col Ⅲ were determined by applying RT-PCR. Results The phosphorylation of smad2/3 in HK-2 cells induced by TGF-β1 was earlier than the down-regulation of E-cadherin and the synthesis of α-SMA. After the intervention of Cur, the expressions of TFβR- Ⅱ , Col Ⅰ -mRNA and Col Ⅲ -mRNA, and phosphorylation of smad2 were inhibited significantly. The expression of smad7 was improved. Conclusion Cur can obstruct EMT process through interfering multiple sites of TGF-β1/smads signal transduction pathway.