MG132对高糖条件下肾小管上皮细胞SnoN蛋白表达及纤维化效应的影响

Effects of MG132 on protein expression of SnoN and fibrosis-related indicators in NRK-52E cells after incubated with high concentration of glucose

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Sno N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Sno N、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Sno N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Sno N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Sno N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 .