JNK对转化生长因子β1所致大鼠腹膜间皮细胞转分化的调控作用

目的 探讨c-Jun 氨基末端激酶(JNK)在转化生长因子β1(TGF-β1)诱导大鼠腹膜间皮细胞（RPMC）转分化中的调控作用。 方法 采用腹腔注射胰蛋白酶法分离培养RPMC，取第2代腹腔间皮细胞用于实验研究。观察TGF-β1对α平滑肌肌动蛋白(α-SMA)、Ⅰ型胶原(ColⅠ)、E钙黏蛋白(E-cadherin)以及磷酸化(p)JNK表达的影响；应用JNK特异性抑制剂SP600125预处理细胞后，观察其对TGF-β1所致上述作用的影响。RT-PCR法检测α-SMA、ColⅠ及E-cadherin mRNA表达；Western印迹法检测α-SMA、ColⅠ、E-cadherin及p-JNK蛋白表达；间接免疫荧光检测α-SMA在细胞内的表达和分布。 结果 TGF-β1刺激RPMC能导致α-SMA、ColⅠ蛋白表达上调，E-cadherin蛋白表达下调，呈时间依赖性。TGF-β1刺激RPMC 5 min出现p-JNK表达上调，10 min达高峰(P < 0.01)。SP600125能够抑制JNK的磷酸化(P < 0.05)，也能抑制TGF-β1诱导的α-SMA、ColⅠmRNA和蛋白的高表达以及E-cadherin表达的下调 (均P < 0.05)。间接免疫荧光结果显示，TGF-β1刺激RPMC 48 h，胞内α-SMA表达明显增多，SP600125能有效抑制其高表达。 结论 JNK在TGF-β1诱导大鼠腹膜间皮细胞转分化中具有重要的调控作用，JNK特异性抑制剂的应用可能为临床防治腹膜纤维化提供新的途径。

JNK regulates epithelial mesenchymal transition induced by transforming growth factor β1 in rat peritoneal mesothelial cells

Objective To investigate the role of C-Jun N-terminal kinase (JNK) in epithelial mesenchymal transition (EMT) induced by transforming growth factor β1 (TGF-β1) in rat peritoneal mesothelial cells(RPMCs). Methods RPMCs were harvested from the peritoneum of male Sprague-Dawley rats, then cultured in DMEM/F12 medium with 15% (V/V) FBS. After stimulation with TGF-β1, the expression of a-smooth muscle actin (α-SMA), E-cadherin and collagen I were detected in RPMCs. In some groups, the ceils were pretreated with SP600125, a specific inhibitor of JNK, for 4 hours before incubation with TGF-β1. The protein expression of phosphorylated JNK was detected by Western blotting. The mRNA and protein expression ofα-SMA, E-cadherin and collagen I were examined with RT-PCR and Western blotting, respectively.The intracellular distribution and expression of α-SMA was determined by indirect immunofluorescence. Results TGF-β1 could significantly increase the expression of α-SMA and collagen I, and decrease the expression of E-cadherin in RPMCs. TGF-α1 could stimulate the expression of phosphorylated JNK at 5 minutes with the peak at 10 minutes (P<0.01). The addition of SP600125 effectively inhibited TGF-β1-induced high expression of α-SMA and collagen I (P<0.05), and prevented TGF-β1-induced down-regulation of E-cadherin expression in RPMCs (P<0.05). The indirect immunofluorescence showed that the expression of intracellular α-SMA in RPMCs stimulated by TGF-β1 for 48 h increased significantly, which could be inhibited by SP600125. Conclusions JNK regulates epithelial mesenchymal transition induced by TGF-β1 in rat peritoneal mesothelial cells. JNK inhibitor may be used as a novel therapeutic agent for peritoneal fibrosis.