间质干细胞来源exosome抗肝纤维化作用机制研究

肝纤维化治疗目前尚缺乏很好的方法，间质干细胞（MSCs）移植在肝纤维化治疗中的作用越来越引起人们的重视。我们初步研究发现脐带MSC来源的囊泡（MSC-exosome）作为脐带MSCs旁分泌的活性成分能够抑制四氯化碳诱导的小鼠肝纤维化，然而其抑制作用机制并不清楚。为此，本课题以MSC-exosome在肝纤维化中向肝星状细胞转移的microRNAs为切入点，体内外观察MSC-exosome对肝星状细胞活化的抑制作用；采用microRNA芯片筛选MSC-exosome向肝星状细胞转移的microRNAs；明确MSC-exosome抑制肝星状细胞活化的关键miRNAs；寻找关键miRNAs调控的肝星状细胞活化相关靶基因及信号传导通路，阐明MSC-exosome修复肝纤维化的作用机制。本研究将为MSC-exosome治疗肝纤维化提供新的思路和实验依据，具有十分重要的价值和临床应用前景。

There are still no effective antifibrotics available and mesenchymal stem cells (MSCs) transplantation has recently gained increasing attention in liver fibrosis. Our preliminary study suggested that MSC derived exosome(MSC-exosome), an active component secreted by MSCs, could ameliorate carbon tetrachloride induced liver fibrosis in mice. However, the mechanisms for this inhibition remain unknown. Activation of hepatic stellate cells (HSCs) is the key event in liver fibrosis, whereas previous studies have demonstrated an important role of microRNAs during the activation of HSCs. We therefore hypothesize that exosome-mediated transfer of microRNAs play a critical role in MSC-exosome's inhibition of HSCs activation in liver fibrosis. To test the hypothesis, my research will focus on the following three specific aims: Aim 1) Determine the role of MSC-exosome in HSCs activation through in vivo and in vitro experiments.Aim 2) Identify the key microRNAs roled in HSCs activation by using microRNA microarray for microRNAs screening and microRNA modified MSC-exosome for microRNA activity assay.Aim 3) Determine the target genes and pathways of the key microRNAs involved in HSCs activation,which will be predicted through microRNA target gene databases? and verified by using various molecular biological approaches including Luciferase Reporter Gene Assay, Western blot, quantitative real-time PCR. We expect that the results obtained from proposed studies will help us to understand how MSC-exosome works in liver fibrosis, which could lead to improved therapy design and provide the molecular basis for the development of new therapeutic methods for liver fibrosis. Thus, it is of great value and clinical application prospects.