携miRNA-21间充质干细胞外泌体调控肾小管上皮细胞自噬并减轻慢性肾损伤的机制研究

Mesenchymal stem cells (MSCs) are fairly effective in the treatment of a variety of kidney disease models, and to clarify the therapeutic mechanism helps to apply MSCs to a safe and effective clinical treatment. Our preliminary experiments showed that exosomes secreted by human umbilical cord MSCs (hucMSC-Ex) were abundant in miR-21, which can ameliorate renal tubular epithelial cell injury, but the mechanism is not clear. Recent studies suggest that miRNA-21 significantly inhibits autophagy progress and the autophagy level is closely associated with cell injury. Thus we hypothesize that hucMSCs secrete exosomes carrying miRNA-21 can be absorbed by renal tubular epithelial cells and further attenuate cells injury by regulating autophagy. In this study, co-culture of hucMSC-Ex and rat renal tubular epithelial cells (NRK-52E), and kidney injury animal model are established. Furthermore, experimental techniques of gene interference, autophagy regulation and animal experiments are to be used to clarify the molecular mechanism that hucMSC-Ex ameliorate renal tubular epithelial cell injury by intercellular information transmission, which will provide a clinically theoretical basis for stem cell treatment in kidney diseases.

间充质干细胞（MSCs）对多种肾脏疾病模型具有良好的治疗效果，阐明其作用机制有助于更好地将干细胞治疗推广到临床应用。课题组前期研究发现脐带间充质干细胞外泌体（hucMSC-Ex）通过高表达miRNA-21减轻肾小管上皮细胞损伤，但其起效的具体机制尚不清楚。新近研究提示miRNA-21显著抑制自噬进程，且自噬水平的变化与细胞损伤密切相关。因此，我们推测：hucMSCs分泌携带miRNA-21信号的外泌体被肾小管上皮细胞接收后，可能通过调控细胞内自噬水平，从而减轻细胞损伤。本课题拟建立hucMSC-Ex与大鼠肾小管上皮细胞（NRK-52E）共培养体系以及肾脏损伤模型，采用基因干扰、自噬调控及动物实验等方法，阐明hucMSC-Ex通过细胞间信息传递减轻肾小管上皮细胞损伤的分子机制，为临床干细胞治疗肾脏疾病提供理论依据。

间充质干细胞（MSCs）对多种肾脏疾病模型具有良好的治疗效果，阐明其作用机制有助于更好地将干细胞治疗推广到临床应用。最新研究显示，MSCs来源的外泌体能模拟MSCs多种生物学功能，促进组织损伤修复，具有广阔的临床应用前景。本项目在前期研究的基础上，将脐带间充质干细胞外泌体（hucMSC-Ex）引入慢性肾病肾脏损伤修复研究中，深入探讨了外泌体在慢性肾病中对于肾脏结构和功能的保护作用以及肾小管上皮细胞（NRK-52E）自噬水平的调控作用，研究结果发现：1.超速离心法可以高效地提取出hucMSC-Ex，从而为慢性肾病治疗及肾脏损伤修复提供可能；2.体内研究表明，hucMSC-Ex通过miR-146a-5p/TRAF6调控单侧输尿管梗阻大鼠肾脏自噬，减轻肾脏组织纤维化，有效改善肾脏功能；3.体外研究表明，NRK-52E细胞损伤时，hucMSC-Ex携带并释放miR-146a-5p，负向调节TRAF6的表达，提高细胞自噬水平，改善NRK-52E上皮细胞间质转化。上述问题的探索和解决，揭示了MSCs通过外泌体介导的细胞间信息传递调控宿主细胞功能并发挥疗效的新机制，为MSCs移植治疗的临床应用提供了重要的理论思路和研究基础。在本项目的资助下，课题组共发表研究论文7篇，其中SCI论文5篇，毕业博士研究生1名，硕士研究生2名。