血小板微粒活化mTOR通路介导糖尿病肾病早期肾小球内皮损伤的作用研究

Diabetic nephropathy (DN) is a chronic diabetic microvascular complications with high mortality and morbidity, however, its mechanism remains unknown. Platelet microparticles (PMP) are submicroscopic membrane vesicles released from activated platelets, containing the inflammatory cytokines and other active protein components. Circulating PMP is significantly increased in early stage of DN and can directly contact with glomerular endothelium through the blood. Our previous work demonstrated that PMP stimulated glomerular endothelial cells (GECs) to excret inflammatory cytokines, activate mammalian target of rapamycin (mTOR) pathway, induce endothelial-to-mesenchymal transition (EndMT), and damage of cellular junction. Therefore, based on our results of pilot studies, this project aims to dynamically observe the effects of PMP on the injuries of glomerular endothelium using diabetic rat model induced by streptozotocin and cell culture model of GECs, and further explore the potential mechanism of mTOR activation and inflammation induced by PMP in GECs injury through the application of mTORC1 inhibitors, mTORC2 gene silence technology, protein microarray,and live cell imaging technology. It is expected that this study will clarify the role of PMP in glomerular endothelial injury of DN and provide a novel theoretical and experimental basis for finding new intervention targets to prevent the early progression of DN.

糖尿病肾病（DN）是糖尿病慢性微血管并发症，致死、致残率高，但其机制至今尚未完全阐明。血小板微粒(PMP)是血小板激活后释放的一种超微膜性囊泡，含有炎症因子等多种活性蛋白成分。DN早期血循环中PMP显著升高，经血液与肾小球内皮细胞（GECs）直接接触，可能在GECs损伤中起关键作用。我们前期预实验结果证实，PMP能够刺激GECs释放炎症因子、活化mTOR通路、诱导GECs发生细胞表型转化、破坏细胞间紧密连接。因此，本研究拟在前期工作基础上，采用链脲佐菌素诱导的糖尿病大鼠模型、GECs细胞培养模型，应用mTORC1抑制剂、mTORC2基因沉默及蛋白芯片、活细胞实时成像等技术，动态观察PMP在肾小球内皮损伤中的作用，以探讨PMP在介导炎症反应、活化mTOR通路、促进GECs损伤中的调控机制。研究将阐明PMP在DN早期肾小球内皮损伤中的发生机制，为DN早期治疗提供新颖的实验和理论依据。

糖尿病肾病（DN）是糖尿病慢性微血管并发症，具有很高的致死、致残率，但其机制至今尚未完全阐明。血小板微粒(PMP)是血小板激活后释放的一种超微膜性囊泡，含有炎症因子等多种活性蛋白成分。研究表明，DN早期血循环中PMP显著升高，经血液与肾小球内皮细胞（GEnCs）直接接触，可能在DN早期GECs损伤中发挥关键作用。本研究应用链脲佐菌素诱导的糖尿病大鼠模型、原代GEnCs细胞培养模型证实，糖尿病组大鼠血循环中PMP水平较对照组显著增加，并伴有肾小球组织中PMP沉积增加。而阿司匹林能够有效降低糖尿病大鼠血PMP水平，减少肾小球中PMP的沉积，逆转PMPs诱导的GEnCs细胞内ROS产生增加，NO水平减少，eNOS、SOD活性下降；逆转PMP诱导的GEnCs核心蛋白glypican-1、sydecan-1及连接蛋白ZO-1、occludin-1表达减少，ET-1表达增加。应用蛋白芯片技术进一步分析发现，PMP中含有大量的趋化因子CXCL7。PMPs能够通过释放CXCL7激活mTOC1通路，促进其下游蛋白4EBP1、S6K1磷酸化，介导DN早期肾小球内皮细胞损伤，促进微量白蛋白尿的发生及DN进展。本研究初步阐明了PMP在DN 早期肾小球内皮损伤中的作用及发生机制，为临床发现新的干预靶点，阻止DN 早期进展提供了实验依据和新思路。