摘要目的 观察高糖环境中足细胞核苷酸结合寡聚化结构域蛋白2(NOD2)、上皮-间质转分化(EMT)相关蛋白的表达,探讨NOD2参与EMT的分子机制.方法 常规方法培养人肾小球足细胞,高糖刺激后细胞免疫荧光法检测EMT相关蛋白α平滑肌肌动蛋白(α-SMA)、nephrin的表达;实时荧光定量PCR和Western印迹法检测NOD2、锌指转录因子(Snail)和足细胞EMT相关蛋白α-SMA、结蛋白(Desmin)、上皮型钙黏蛋白(E-cadherin)及Nephrin的表达.shRNA干扰NOD2表达后再给予高糖刺激细胞,Western印迹法检测Snail及后续EMT相关蛋白的表达情况.用shRNA干扰Snail表达后,胞壁酰二肽(MDP)活化NOD2,Western印迹法检测E-cadherin、Nephrin、Desmin、α-SMA的表达.结果 高糖刺激24 h后,与正常对照组相比,高糖组NOD2、Snail mRNA和蛋白的表达明显增加;上皮表型蛋白E-cadherin、Nephrin mRNA和蛋白的表达下调,间质表型蛋白Desmin、α-SMA mRNA和蛋白的表达上调(均P＜0.05);高渗对照组无明显变化.干扰NOD2表达后,Snail及EMT相关蛋白表达异常均得到恢复,与高糖组相比差异有统计学意义(均P＜ 0.05).与MDP组相比,MDP+shRNA-Snail组细胞E-cadherin、Nephrin蛋白的表达明显增加;Desmin、α-SMA表达明显减少(均P＜0.05).结论 高糖可诱导足细胞NOD2表达,并通过上调Snail表达促进足细胞上皮-间质转分化.以NOD2/Snail/EMT通路为靶点的基因干预可减轻高糖引起的足细胞损伤,可能为糖尿病肾病的治疗提供新思路.

abstractsObjective To observe the expression of NOD2 and epithelial-mesenchymal transition (EMT) related proteins in podocytes in high glucose environment,and explore the molecular mechanism of NOD2 involved in EMT.Methods The human glomerular podocytes were the subjects of study.α-SMA and Nephrin expressions were detected by immunofluorescence;the mRNA and protein expressions of NOD2,Snail and EMT related proteins (α-SMA,Desmin,E-cadherin,Nephrin) were detected by real-time fluorescence quantitative PCR and Western blotting.The podocytes were stimulated by high-glucose after shRNA interfering the of NOD2 expression,and the expressions of Snail and subsequent EMT-related proteins were detected by Western blotting.Prior to the activation of NOD2 by muramyl dipeptide (MDP),shRNA was used to interfere with the expression of Snail.E-cadherin,Nephrin,Desmin,and α-SMA were detected by Western blotting.Results After 24 hours of high glucose stimulation,PCR and Western blotting results showed that the expressions of NOD2 and Snail were significantly increased;the expressions of epithelial phenotype proteins E-cadherin and Nephrin were down-regulated;and the expressions of interstitial phenotype proteins Desmin and α-SMA were increased (all P ＜ 0.05);while there was no significant change in the hypertonic control group.After interference with NOD2,the abnormal expression of Snail and EMT related proteins were all recovered.After interference with Snail expression,Compared with the MDP group,the protein expressions of E-cadherin and Nephrin were significantly increased (all P ＜ 0.05);the expressions of Desmin and α-SMA were significantly decreased.Conclusions High glucose can induce NOD2 expression in podocytes,and promote podocyte epithelial-mesenchymal transition by upregulating Snail expression.Gene intervention targeting the NOD2/Snail/EMT pathway can reduce high-glucose-induced podocyte injury and may provide new ideas for the treatment of diabetic nephropathy.