蛋白激酶MST1/2活性切割片段负调控肾小管上皮细胞p65核转位抑制肾纤维化的分子机制研究

肾纤维化中受损肾小管上皮细胞炎症反应的分子机理尚未阐明。我们前期研究证实，肾小管特异性Mst1/2（哺乳动物Ste20样激酶1/2）敲除小鼠会自发肾纤维化，并以缺陷型肾小管上皮细胞来源的炎症因子分泌增多为诱因。预实验发现：正常小鼠肾脏中MST1/2以大约36 kD活性切割片段（C-MST1/2）为主；纤维化小鼠肾脏中C-MST1/2表达显著降低；进一步发现小鼠肾内髓集合管细胞过表达C-MST1/2能抑制TNF-α引起的p65入核。据此推测：C-MST1/2可能是肾纤维化的抑制分子，其通过负调控p65核转位来抑制肾小管上皮细胞炎症反应及肾间质纤维化。本课题拟采用水动力转染、定点突变、蛋白过表达等技术阐明C-MST1/2对肾纤维化的抑制作用，并以C-MST1/2表达失调介导p65核转位为新视点揭示肾小管上皮细胞炎症反应的分子机制，为肾纤维化的防治及早期炎症干预提供新思路。

The molecular mechanism underlying inflammatory response of injured tubular epithelial cells in renal fibrosis remains elusive. Our previous study has confirmed that tubule-specific Mst1/2 (mammalian Ste20-like kinase 1/2) knockout leads to spontaneous renal fibrosis in mice, and increased secretion of inflammatory factors that derived from defective tubular cells triggers the fibrotic progression. Preliminary data show that MST1/2 in normal mouse kidney exist mainly as truncated 36 kD active fragments (C-MST1/2); expression of C-MST1/2 is significantly reduced in fibrotic kidney; furthermore, overexpression of C-MST1/2 inhibits p65 nuclear translocation induced by TNF-α in mouse inner medullary collecting duct (mIMCD3) cells. On this basis, we speculate that C-MST1/2 may serve as inhibitory molecules to suppress inflammatory response of tubular cells and renal tubulointerstitial fibrosis through negative regulation of p65 nuclear translocation. This study aims to elucidate the inhibitory role of C-MST1/2 in renal fibrosis, and reveal the molecular mechanism of inflammatory response in tubular epithelial cells resulted from imbalanced C-MST1/2-mediated p65 nuclear translocation by hydrodynamic transfection, site-directed mutagenesis, protein overexpression, etc., which may provide new thoughts in prevention and intervention of early inflammation in renal fibrosis.