原钙黏附蛋白7在脂多糖诱导的肾小管上皮细胞焦亡中的作用

目的 探讨原钙黏附蛋白7（PCDH7）是否参与脂多糖（LPS）刺激引起的肾小管上皮细胞（HK-2）焦亡过程。方法 构建LPS刺激HK-2损伤模型,使用RT-PCR和蛋白免疫印迹法检测细胞中PCDH7、NLR家族Pyrin域蛋白3（NLRP3）、caspase-1、和IL-1β蛋白的表达变化。MTT法测定细胞活力,TUNEL法确定细胞焦亡率,ELISA法检测细胞分泌TNF-α、IL-6水平,全自动生化分析仪检测培养液中乳酸脱氢酶（LDH）含量。结果 与Control组比较,LPS组细胞生存率下降,细胞凋亡率升高,炎症因子TNF-α和IL-6水平升高,细胞损伤指标LDH含量明显升高,PCDH7的蛋白和mRNA表达明显下调,细胞焦亡指标NLRP3、caspase-1、IL-1β蛋白和mRNA表达明显上调（P均< 0.05）。结论 LPS通过下调PCDH7的表达,促进肾小管上皮细胞发生明显细胞焦亡损伤。

Effect of PCDH7 on LPS-induced renal tubular epithelial cell pyroptosis

Objective To investigate whether protocadherin 7 （PCDH7） participates in the progress of renal tubular epithelial cell pyroptosis induced by lipopolysaccharide （LPS）. Methods HK-2 cell was stimulated by 2 μg/mL LPS to construct renal tubular epithelial cell injury model. The changes in the expression levels of PCDH7, NLRP3, caspase-1, and IL-1β in cells were detected by RT-PCR and western blot. MTT assay was used to detect cell viability. TUNEL assay was employed to determine pyroptosis rate. ELISA was adopted to detect the secretion of TNF-α and IL-6 in cells. The content of lactate dehydrogenase （LDH） in culture medium was detected by automatic biochemical analyzer. Results Compared with the control group, cell viability was decreased, while pyroptosis rate was increased. The expression levels of TNF-α and IL-6 were up-regulated. The expression level of LDH, a biomarker of cell damage, was significantly elevated. The expression levels of PCDH7 and mRNA were significantly down-regulated. The expression levels of NLRP3, caspase-1, IL-1β and mRNA were significantly up-regulated in the LPS group （all P < 0.05）. Conclusion LPS can induce renal tubular epithelial cell pyroptosis by down-regulating the expression of PCDH7.