目的：观察蛋白酶体抑制剂MG132对高糖培养条件下肾小管上皮细胞核转录共抑制因子SnoN蛋白表达的影响，探讨MG132减轻高糖状态下肾小管纤维化病变的作用及可能机制。方法：将体外培养的NRK-52E细胞分为正常组（NG）、高糖组（HG）和不同浓度MG132预处理后高糖培养组（HG＋MG132），采用免疫荧光双染的方法观察E-钙黏蛋白（ E-cadherin ）和α-平滑肌肌动蛋白（α-SMA ）在肾小管上皮细胞中的表达和分布，用Western blotting方法检测SnoN、Samd泛素化调节因子2（Smurf2）、Arkadia、E-cadherin、α-SMA和Ⅰ型胶原（Col-Ⅰ）等目标蛋白的相对表达量。结果：与NG组相比，HG组肾小管上皮细胞E-cadherin和SnoN表达减少（P＜0.05），而α-SMA、Col-Ⅰ、Smurf2和Arkadia表达增多（ P＜0.05）；与HG组相比，不同浓度MG132预处理肾小管上皮细胞后高糖培养，可见肾小管上皮细胞中SnoN和E-cadherin蛋白表达显著上调（ P＜0.05），而α-SMA和Col-Ⅰ蛋白的表达显著下调（ P＜0.05），并且这种效应呈量效依赖性，但MG132预处理对Smurf2和Arkadia的表达无影响。结论：MG132可对抗高糖介导的肾小管上皮细胞的纤维化效应，其机制可能是通过减少SnoN蛋白的泛素化降解作用实现的。%AIM:To investigate the effects of proteasome inhibitor MG 132 on the expression of SnoN in renal tubule epithelial cells incubated in high glucose , and to explore the possible mechanism and function that MG 132 reduces or slows down renal tubular interstitial injury after incubated in high glucose .METHODS:The NRK-52E cells were divid-ed into normal control group (NG), high glucose group (HG) and high glucose plus pretreatment with different doses of MG132 group (HG+MG132).The immunofluorescence staining was used to detect the protein expression of E-cadherin and α-smooth muscle actin (α-SMA) in NRK-52E cells under different conditions .The relative protein expression levels of SnoN, Smad ubiquitination regulatory factor 2 (Smurf2), Arkadia, E-cadherin, α-SMA and collagen type Ⅰ(Col-Ⅰ) were detected by Western blotting .RESULTS:Compared with NG group , the expression of E-cadherin and SnoN was de-creased (P<0.05), while the expression of α-SMA, Col-Ⅰ, Smurf2 and Arkadia was increased (P<0.05).Compared with HG group, the protein expression of SnoN and E-cadherin was significantly up-regulated in HG+MG132 group ( P<0.05 ) , and the protein expression of α-SMA and Col-Ⅰwas significantly down-regulated in a dose-depended manner ( P<0.05).However, no effect on the protein expression of Smurf2 and Arkadia was observed.CONCLUSION: MG132 in-hibits the degradation of SnoN protein induced by high glucose , thus reducing the renal fibrosis .
展开▼
