间充质干细胞经EGFR信号通路的介导调控足细胞骨架蛋白修复的机制研究

Proteinuria is an important factor leading to the loss of renal allograft. It is difficult to treat. In order to explore new therapies, we observed that the proteinuria of adriamycin nephrosis SD mice treated with MSCs was reduced significantly. Infusion of MSCs was also shown to increase the expression of synaptopodin, skeleton of podocyte. However, the underlying molecular mechanism was largely unknown. Based on our preliminary finding that there exists EGF expression in MSCs, we proposed that MSCs may enhance the expression of synaptopodin via activating the EGFR/PI3K/Akt/mTOR signaling pathway through paracrine of EGF, which in turn results in repair of damaged podocytes. To test our hypothesis, we will focus our study on exploring the underlying molecular mechanism of the MSCs-induced expression of synaptopodin in podocytes via in vivo co-culture of MSCs with adriamycin-treated podocytes, and in vivo infusion of MSCs in adriamycin-induced nephropathy rats, in combination with detection of the expression levels of synaptopodin, EGFR, Akt, mTOR, S6K1 and 4EBP1. The fulfillment of current proposed study will help to unravel the EGFR signaling-related molecular mechanism of MSCs therapy.

蛋白尿是导致移植肾失功的重要因素，治疗困难。为探究新的疗法，我们的前期研究发现MSCs治疗阿霉素肾病SD大鼠后，其蛋白尿得到明显的控制；MSCs的输注能显著促进足细胞骨架蛋白synaptopodin的表达，但其确切的分子机制不详。进一步的实验结果表明MSCs中存在EGF的表达。据此我们提出假说：MSCs可能通过旁分泌EGF以激活足细胞EGFR/PI3K/Akt/mTOR信号转导通路，促进骨架蛋白synaptopodin的翻译，进而介导足细胞的损伤修复。为验证这一机制，本课题拟进行MSCs与足细胞（阿霉素预处理）体外共培养、MSCs治疗阿霉素肾病SD大鼠等实验，采用Western blot、RT-PCR、shRNA等技术在蛋白和基因水平检测各组足细胞synaptopodin、EGFR、Akt、mTOR、S6K1和4EBP1的表达变化,以阐明EGFR信号通路在MSCs治疗中的作用与分子机制。