间充质干细胞外泌体传递miR-125b调控ALI过度炎症反应的机制研究

急性肺损伤(ALI)是导致危重患者呼吸衰竭的主要原因之一,目前治疗效果欠佳。我们前期研究证实间充质干细胞（MSC）外泌体能修复ALI，但具体机制未明。我们采用miRNA芯片和生物信息学分析，发现MSC外泌体中miRNA-125b表达明显上调，且靶标于Traf6基因，推测其可能参与调控ALI的炎症反应。本项目拟通过慢病毒转染技术分别构建miR-125b过表达和miR-125b抑制表达的MSC外泌体，在LPS诱导的细胞和小鼠模型中，观察不同miR-125b表达水平的MSC外泌体对ALI过度炎症反应的影响；并通过荧光素酶报告基因分析技术验证miR-125b与Traf6的标靶关系，深入探讨miR-125b对Traf6下游NF-κB信号通路的影响，初步阐明MSC外泌体对ALI的修复机制，为临床防治ALI提供新的理论基础和实验依据。

Acute lung injury (ALI) is considered to be the major cause of respiratory failure in critically ill patients, which lacks effective intervention. Our recent study found mensenchymal stem cell (MSC) derived exosomes could restore ALI, However, the exact molecular mechanisms involved in this process remain unclear. Through microarrays single-channel fluorescence chip and bioinformatics analysis, we found that miR-125b was significantly increased in MSC derived exosomes and Traf6 was one of its target genes. It might be involved in the regulation of the inflammatory response of ALI. Using recombinant lentivirus vector technology, low and high miR-125b expression MSC derived exosomes will be built. The effects of MSC derived exosomes with different expression level of miR-125b on the lung injury induced by endotoxin will be observed in vitro and in vivo, respectively. Using luciferase reporter vector, we will demonstrate that miR-125b siginificantly block the expression of Traf6. Additionally, we will also explore the effect of miR-125b on the NF-κB signal pathway, which is downstream of Traf6. The present work will disclose the protective role and its underlying mechanisms of MSC derived exosomes on ALI induced by endotoxin and lay a foundation for the prevention and treatment of ALI.