JNK-c-Jun信号通路下调连接蛋白43的表达引起肾小管上皮细胞转分化

JNK-c-Jun signal pathway induces tubular epithelial-myofibroblast transition via down-regulation of connexin 43 expression

目的观察c-Jun氨基末端激酶（JNK）-c-Jun通路对连接蛋白43（Cx43）表达的影响及在转化生长因子（TGF）131诱导的肾小管上皮细胞一肌成纤维细胞转分化（TEMT）中的作用。方法大鼠肾小管上皮细胞（NRK．52E）随机分成3组：对照组、TGF-131（10μg/L）组和TGF．B1（10斗g，L）＋JNK选择性抑制剂SP600125（50Ixmol／L）组。用免疫细胞化学、Western印迹检测JNK、c-Jun、连接蛋白43（Cx43）、上皮细胞标志物E-钙黏蛋白（E-cadherin）和肌成纤维细胞标志物仪-SMA的表达。用RT-PCR检测Cx43的mRNA水平。用激光共聚焦显微镜荧光漂白恢复（FRAP）技术检测NRK-52E细胞间通讯功能。结果TGF-β1引起肾小管上皮细胞α-SMA、JNK、c．Jun表达上调（均P〈0．05），Cx43、E-cadherin表达下调（均P〈0．05），Cx43的mRNA水平下降（P〈0．05），细胞间通迅功能下降（P〈0．05）。JNK抑制剂处理后，上述改变明显减轻。结论TGF-β1引起肾小管上皮细胞内JNK表达上调，增加c-Jun活性，从而抑制Cx43的表达和降低细胞间通迅功能，导致TEMT。

Objective To explore the effect of JNK-c-Jun signal pathway on connexin 43 （Cx43） expression and its role in renal tubular epithelial-myofibroblast transition （TEMT） induced by TGF-IM. Methods Normal rat kidney tubular epithelial cells （NRK-52E） were cultured in Dulbecco＇s modified eagle medium （DMEM） with 10% fetal bovine serum, then were randomly divided into 3 groups： control group, TGF-β1 group （treated with TGF-131 10 μg/L）, and TGF-β1＋ SP600125 （selective JNK inhibitor, 50μmol/L） group. The protein expressions of JNK, c-Jun, α- SMA, Cx43 and E-cadherin were assayed by immunocytochemistry and Western blotting. The Cx43 mRNA was assayed by RT-PCR. Gap junction intercellular communication （CJIC） was measured by fluorescence recovery after photobleaching assay （FRAP）. Results TGF-β1 increased the expressions of JNK, c-Jun andα-SMA （P〈O.05）, reduced the expressions of Cx43 and E-cadherin （P 〈0.05）, and inhibited GJIC of NRK-52E （P 〈0.05）. SP600125 could alleviate the above expressions changes and enhanced GJIC induced by TGF-[31. Conclusion JNK-c-Jun signal pathway induces TEMT of NRK-52E treated with TGF-β1 via down-regnlation of connexin 43expression and inhibition of GJIC.