Erbin在肾间质纤维化中的表达和作用

目的 探讨Erbin在肾脏间质纤维化中表达量的变化及上调Erbin对转化生长因子β1（TGF-β1）诱导大鼠近端肾小管上皮细胞（NRK52E）转分化的影响。 方法 体内实验采用SD大鼠5/6肾切除法建立肾纤维化动物模型，收集并检测各组血清中Scr、BUN水平；Masson染色观察肾间质纤维化程度；免疫组化及Western印迹检测Erbin的分布与表达。 体外实验采用TGF-β1（10 μg/L）刺激NRK52E细胞72 h建立上皮细胞-间充质转分化（EMT）细胞模型；免疫荧光及Western印迹法检测E钙黏蛋白（E-cadherin）和α平滑肌肌动蛋白（α-SMA）的表达变化；RT-PCR及Western 印迹法检测Erbin的表达变化。用脂质体2000将质粒 Prk5-myc-Erbin瞬时转染至NRK52E细胞，Western印迹法观察上调Erbin表达后对上述各种指标的影响。 结果 （1）假手术组大鼠肾功能正常Scr（33.96±7.28） μmol/L、BUN（8.11±2.55） mmol/L]，Masson染色未见肾间质纤维化，Erbin在肾小管表达较少；模型组大鼠Scr （140.52±61.11） μmol/L]、BUN（34.23±7.66） mmol/L] 均显著高于假手术组（均P < 0.05），肾间质可见明显纤维化，Erbin 在肾小管表达也明显增加，是假手术组的2.9倍（P < 0.01）。（2）正常NRK52E 细胞表达E-cadherin，少量表达Erbin和α-SMA。TGF-β1刺激后，NRK52E细胞E-cadherin表达显著减少，Erbin和α-SMA则表达增加（均P < 0.05）；而转染质粒Prk5-myc-Erbin可逆转TGF-β1诱导的NRK52E细胞E-cadherin表达下调，并可抑制α-SMA表达上调（均P < 0.05）。 结论 Erbin在肾间质纤维化中表达增加，上调Erbin表达可抑制TGF-β1诱导NRK52E发生EMT， 提示Erbin在肾脏纤维化中可发挥保护作用。

The expression and function of Erbin protein in renal interstitial fibrosis

Objective To investigate the expression of Erbin in renal interstitial fibrosis (RIF) and the effect of over-expression of Erbin on transforming growth factor β1 (TGF-(β1)-induced epithelial-mesenchymal transition (EMT) in NRK52E cells. Methods In vivo, the model of renal fibrosis was induced by 5/6 subtotal nephrectomy in rat. Scr and BUN was detected and Masson staining was used to evaluate the level of renal tissue fibrosis. The location and expression of Erbin in renal tissue were detected by immunohistochemistry and Western blotting. In vitro, after NRK52E cells were treated by TGF-β1 (10 μg/L) for 72 h, immunofluorescence and Western blotting were used to obverse the expression and distribution of E-cadherin and α-SMA. The expression of Erbin mRNA and protein were detected by RT-PCR and Western blotting respectively. NRK52E cells were transiently transfected with Prk5-myc-Erbin plasmid via lipofectamine 2000, then the expressions of Erbin, E-cadherin and α-SMA were detected by Western blotting. Results (l)Compared to sham group with Scr (33.96±7.28) μmol/L and BUN (8.11±2.55) mmol/L, rats in 5/6 nephrectomy model with Scr (140.52±61.11) μmol/L and BUN (34.23±7.66) mmol/L revealed renal dysfunction. Masson staining indicated kidney interstitial fibrosis, and the expression of Erbin was significantly increased in renal tissue(2.9 folds), especially in tubular epithelia. (2)In vitro, the expressions of Erbin and α-SMA were markedly increased (2.3 folds and 2.1 folds, P<0.05, respectively) and the expression of E-cadherin was dramatically decreased in NRK52E cells stimulated by TGF-β1, which were consistent with immunofluorescence results. TGF-β1-induced E-cadherin suppression and a-SMA induction could be efficiently blocked by over-expression of Erbin (all P <0.05). Conclusions Erbin is up-regulated in renal interstitial fibrosis, and over-expression of Erbin can partly inhibit renal EMT induced by TGF-β1, which indicates Erbin playing an protective role in renal fibrosis.