Jagged1通过AP-1/Snail通路调控EndMT介导的糖尿病肾病的机制研究

Diabetic Kidney Disease is an important cause of chronic renal failure. Recent studies have shown that high glucose-induced endothelial mesenchymal transition (EndMT) is closely related with the occurrence and development of diabetic kidney disease. Inhibition of EndMT can effectively prevent diabetic kidney fibrosis, thus delaying the progression of diabetic kidney disease. Jagged1 is one of the important ligands of Notch signaling pathway, and it has been confirmed that Jagged1 is closely related to diabetic microvascular dysfunction. However, whether Jagged1 is directly involved in the pathogenesis of diabetic kidney disease has not been reported. For the first time, we found that the expression of Jagged1 in glomerular endothelial cells increased significantly under high glucose, but the downstream Notch pathway was not activated. Jagged1 gene silencing can reduce the expression of Snail, the core transcription factor of EndMT, so that the high glucose-induced glomerular EndMT can be reversed. We found that the nuclear translocation of cytoplasmic domain of Jagged 1 (JICD) can directly affect interaction between AP-1 and Snail. Therefore, we hypothesize that Jagged1 can directly regulate EndMT through the AP-1/Snail pathway to mediate the occurrence and development of diabetic kidney disease. This study applies Jagged 1 endothelial specific knockout and overexpression mice, using siRNA, EMSA, dual luciferase reporter gene assay, immunofluorescence technique to prove our hypothesis, so as to provide new therapeutic targets for the prevention and treatment of diabetic kidney disease.

糖尿病肾病是慢性肾衰竭的重要原因。新近研究显示内皮细胞间充质化（EndMT）在糖尿病肾病中发挥重要作用。阻断Notch信号通路可抑制EndMT，而Jagged1是Notch的重要配体，有研究证实Jagged1与糖尿病微血管功能障碍密切相关，但Jagged1是否参与糖尿病肾病的发病未见报道。我们预实验发现，高糖环境下肾小球内皮细胞出现EndMT表型且Jagged1表达显著升高，但Notch通路未被激活。基因沉默Jagged1，EndMT核心转录因子Snail表达下降，EndMT被逆转。我们发现Jagged1可通过胞内区域核转位影响激活蛋白-1（AP-1），且Snail基因启动子中存在AP-1作用位点。因此推测“Jagged1通过AP-1/Snail通路调控EndMT从而介导糖尿病肾病的发生”。本课题拟应用肾小球内皮细胞与Jagged1内皮特异性敲除及过表达小鼠建立糖尿病肾病模型，验证该假说。

研究背景：糖尿病肾病是糖尿病常见的微血管并发症之一,已成为导致慢性肾衰竭和糖尿病患者死亡的重要原因。Jagged1是Notch信号通路的重要配体之一，可以通过激活Notch1通路影响细胞的分化、增殖和凋亡，与糖尿病微血管并发症密切相关。.研究内容：1.Jagged1是否参与糖尿病肾小球内皮间充质化，进而促进糖尿病肾病的进展；2.明确Jagged1介导高糖诱导的肾小球内皮间充质化的具体机制。.重要研究结果：我们发现高糖环境下，Jagged1在肾小球内皮细胞中的表达显著升高，Jagged1可以通过介导肾小球内皮细胞间充质化来加重糖尿病肾病的进展，其机制与过度活化的Jagged1可以通过调控胞内结构JICD的核转位活化AP-1，进而促进内皮间充质化核心转录因子Snail的表达有关。Jagged1基因敲除可以抑制高糖诱导的肾小球内皮细胞间充质化以及通过基因沉默肾小球内皮细胞AP-1可以降低Snail的表达。.关键数据及科学意义：AP-1可以通过直接作用于Snail的启动子，调控内皮细胞向间充质细胞的转化。高糖通过诱导Jagged1胞内结构JICD核转位，促进AP-1的活化，上调Snail的表达，促进内皮细胞向间充质细胞的转化来加重糖尿病肾病的进展。以上结果可能为糖尿病肾病的防治提供新的思路及治疗靶点。