p62 对 TLR4 信号通路的调控效应在糖尿病肾小管上皮细胞炎症中的作用

Diabetic kidney disease (DKD) has become the first cause of end-stage renal disease, which lacks effective intervention in clinic. Recent studies find that inflammation of the tubular epithelial cells mediated by Toll-like receptor 4 (TLR4) is an important pathogenic factor of DKD. Sqstm1/p62 can regulate the TLR4 signaling pathway by binding with TRAF6 directly, which is a hub in the TLR4 downstream pathway. Our preliminary study showed that p62 level was decreased in high glucose cultured renal tubular epithelial cells, while it is not clear whether p62 is involved in the activation of TLR4 pathway in renal tubular epithelial cells of DKD. By using conditional gene knockout, shRNA knockdown and gene over-expression technology, the present study aims to investigate whether p62 is involved in the excessive activation of TLR4 signaling pathway in DKD renal tubular epithelial cells as a downstream mechanism and whether p62 can be used as a new intervention target to have protective effect on DKD through its regulation of TLR4 signaling pathway. By this study, it would have great significance to understand the molecular mechanism of TLR4 signaling pathway in DKD renal tubular epithelial cells and to search for new intervention targets in DKD.

糖尿病肾脏病(Diabetic kidney disease, DKD)是终末期肾病的首位病因。新近研究发现，Toll样受体4(Toll-like receptor 4,TLR4)介导的肾小管上皮细胞炎症是DKD的重要致病因素。多功能蛋白p62可与TLR4通路的TRAF6直接结合，进而对TLR4通路发挥调节效应。项目组前期工作发现，高糖环境下肾小管上皮细胞p62水平降低，而p62是否参与了DKD肾小管上皮细胞TLR4通路的过度激活目前尚不清楚。本项目拟从体内和体外两个水平，应用条件性基因敲除、基因敲减和过表达等研究技术，探讨以下两个问题：p62是否作为一种下游机制参与了DKD肾小管上皮细胞TLR4通路的过度激活；p62能否成为一个有效干预靶点，通过调控TLR4通路对DKD具有保护效应。本项目对于深入理解DKD肾小管上皮细胞TLR4通路激活的细胞内机制，以及寻找DKD新的干预靶点具有重要意义。

糖尿病肾脏病(Diabetic kidney disease, DKD)是终末期肾病的首位病因。新近研究发现，Toll样受体4(Toll-like receptor 4,TLR4)介导的肾小管上皮细胞炎症是DKD的重要致病因素，但其上游调控机制尚不清楚。项目组前期工作发现，高糖环境下肾小管上皮细胞p62水平降低，而p62是否参与了DKD肾小管上皮细胞TLR4通路的过度激活目前尚不明确。本项目首先在体内高糖刺激的肾小管上皮细胞和糖尿病小鼠中验证了糖尿病环境下肾小管上皮细胞炎症增强和EMT伴有 TLR4 信号通路的过度激活，同时p62 蛋白表达降低。通过在 HK-2 细胞中实现 p62过表达，发现 p62降低了 NF-κB介导的炎症因子的释放和 EMT 的发生。并进一步在机制上明确了 p62 通过与 TLR4 下游分子 TRAF6 的相互结合阻断了高糖下肾小管上皮细胞 TLR4 信号通路的过度激活。在体内通过构建肾小管上皮细胞 p62 条件性基因敲除小鼠，观察了其肾脏的结构和功能，及对 p62 和 TLR4 信号通路分子的表达的影响。本项目发现p62过表达能够对高糖诱导的肾小管上皮细胞炎症反应具有改善效应，提示p62 有可能成为一种针对 DKD 肾小管间质炎症的新的干预靶点。本项目的完成对于深入理解DKD肾小管上皮细胞TLR4通路激活的细胞内机制，深化对目前 DKD 小管间质炎症发生机制的认识也具有重要意义。.通过上述研究，以本项目为依托发表通讯作者SCI论文2篇，国际学术会议海报交流两篇，培养硕士研究生1名。