血管干细胞来源的外泌体对卒中后神经再生及功能修复的作用及机制研究

Stem cell-based therapy has demonstrated great potential for improving neurobehavioral recovery after ischemic stroke. However, the underlying mechanisms remain largely unexplored. Our previous studies showed that co-transplantation of vascular progenitor cell (VPC) and neural stem cell (NSC) into ischemic brain improved neurogenesis and neuroplasticity. Further study showed that conditioned medium of VPC significantly promoted the survival and neuronal differentiation of NSC, and exosomes derived from VPC increased the expression of miR-124 and Notch-1 in NSC. Nevertheless, whether and how VPC-derived exosomes regulates the function of NSC is still unknown. In this study, by transplanting VPC-derived exosomes into ischemic mice and using molecular biology approaches, we aim to explore: 1)whether transplantation of VPC-derived exosomes could improve neurobehavioral recovery after stroke by enhancing the survival and differentiation of endogenous NSC; 2)whether VPC-derived exosomes regulates the survival and differentiation of NSC through miR-124, and its downstream target, Notch-1; 3)whether transplantation of VPC-derived exosomes that overexpress miR-124 could further improve the therapeutic efficacy by promoting the survival and differentiation of NSC. The data from this study will shed light on the mechanisms of VPC-mediated neurogenesis and neuroplasticity, and provide a novel treatment strategy for ischemic stroke.

研究提示干细胞移植促进缺血性卒中后神经功能的修复，但其作用机制尚不清楚。我们前期工作发现同时移植血管祖细胞和神经干细胞可有效促进神经再生和功能重塑，进一步实验发现血管祖细胞的条件培液可以促进神经干细胞存活和分化，而且其分泌的外泌体能够促进神经干细胞中的微小RNA-124和Notch-1增加，但这种外泌体能否调控神经干细胞功能及具体机制仍不明确。本课题以小鼠大脑中动脉缺血为模型，移植血管祖细胞分泌的外泌体，通过分子生物学方法探索：1）移植血管祖细胞外泌体是否通过调控缺血后内源性神经干细胞存活及分化，改善神经行为学功能修复；2）血管祖细胞外泌体是否通过微小RNA-124作用下游靶蛋白Notch-1从而调控神经干细胞的存活和分化；3）移植过表达微小RNA-124的血管祖细胞外泌体是否能进一步促进神经干细胞的存活和分化功能。本课题研究将为血管祖细胞对缺血的治疗提供新的理论依据和治疗策略。

研究提示干细胞移植促进缺血性卒中后神经功能的修复，但其作用机制尚不清楚。我们前期工作发现同时移植血管干细胞和神经干细胞可有效促进神经再生和功能重塑，进一步实验发现血管干细胞的条件培液可以促进神经干细胞存活和分化，而且其分泌的外泌体能够促进神经干细胞中的微小RNA-124和Notch-1增加，但这种外泌体能否调控神经干细胞功能，促进神经元的存活和神经干细胞的分化，进而促进机体神经行为学功能的修复及具体机制仍不明确。本研究以小鼠大脑中动脉缺血为模型，移植血管干细胞分泌的外泌体，利用分子生物学、生物化学、miRNA测序、基因转染等技术，通过体内动物模型和体外细胞模型，明确了：1）移植血管干细胞外泌体通过调控缺血后内源性神经干细胞存活及分化，改善缺血小鼠神经行为学功能修复；2）血管干细胞外泌体通过微小RNA-124作用下游靶蛋白Notch-1从而调控神经干细胞的存活和分化；3）移植过表达微小RNA-124的血管干细胞外泌体能进一步促进神经干细胞的存活和分化功能，进而促进机体神经功能修复；4）外泌体的移植通过微小RNA-124减少了卒中后神经元的凋亡，减少了机体的神经损伤；5）外泌体移植能够促进少突胶质前体细胞向少突胶质细胞的分化，进而促进了白质的修复。本课题研究将为血管干细胞对缺血的治疗提供新的理论依据和治疗策略。