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。

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.