Rspo2-LGR通路在胚胎干细胞向血管平滑肌细胞分化和血管损伤修复中的作用及机制研究

胚胎干细胞(ESCs)具有无限增殖和多向分化的潜能，可在体外诱导为血管平滑肌细胞(VSMCs)，但分化机制尚不明确。R-spondin(Rspo)家族是新发现的与发育密切相关的分泌性蛋白，其受体LGR是重要的上皮干细胞分子标记物。本课题组在前期研究中发现Rspo2对小鼠ESCs向VSMCs分化过程起关键作用。本研究拟：1)通过增强或抑制分化过程中Rspo2-LGR通路，明确其对小鼠ESCs向VSMCs分化的调控作用；2)通过激活或抑制分化过程中Wnt/β-catenin通路，探讨Rspo2的促ESCs向VSMCs分化作用是否由Wnt/β-catenin通路介导；3) 在小鼠血管损伤模型中验证Rspo2是否在血管损伤后新生内膜形成中起保护作用。本研究有助于深化对VSMCs分化机制的认识，为今后有效地防治血管疾病提供新的药物靶点，并对干细胞在血管再生医学的应用奠定基础。

Embryonic stem cells (ESCs) possess capacity of indefinite self-renewal and potential for multi-lineage differentiation. ESCs can be induced into vascular smooth muscle cell (VSMC) in vitro, but the underlying mechanism of differentiate remain unknown. R-spondin (Rspo) family have been found to be a group of secreted proteins essential for development, and Rspo receptors LGRs are important epithelial stem cell markers. By applying our well-establish VSMC differentiation model, we have recently found that Rspo2 is critical during SMC differentiation from mouse embryonic stem (ES) cells. In this study, we resolve to 1) determine the role of Rspo2-LGR pathway in VSMCs differentiation from ESCs, through manipulating Rspo2-LGR signaling and observing corresponding change in expression of VSMCs marker and transcription factor, and function of differentiated VSMC; 2) determine if Wnt/β-catenin signaling is required to mediate Rspo2-induced VSMCs differentiation, through observing the effect on VSMCs differentiation by manipulating Wnt/β-catenin signaling; 3) determine whether Rspo2 exert a protective role in neointimal formation in response to vascular injury. Results of our study would help to better understand the biological mechanisms underlying VSMC differentiation and injury-induced neointima formation, and could provide potential drug target therapy for treating vascular disease, and lay a solid foundation for stem cell application in vascular regenerative medicine.