MiR-155/β-arrestin 2/GSK3β通路在Sca-1+心脏干细胞向心肌分化中的功能研究

To mobilize endogenous cardiac cardiac stem cells (CSC) to differentiate into myocardial cells is a new strategy for the treatment of heart failure. Sca-1 CSCs can differentiate into cardiomyocytes, thus they have the potential for the treatment of heart disease, but the mechanism for differentiation is still not clear. β-arrestin2 is an important scaffold protein and highly expressed in the heart. It regulated the cell fate because of it particaipated in many signaling pathways mediated by G-protein-dependent and non-dependent pathway. We found that β-arrestin2 is a key factor in 5-azacytidine-induced differentiation of Sca-1 cardiac stem cells into cardiomyocytes. The process is accompanied by the decline of miR-155 and GSK3β phosphorylation inactivation. According to the literature, we assume 5 Aza induced Sca-1 cells transition to myocardial by miR-155/β-arrestin 2/GSK3β path. This project will focus on the roles of MiR-155 and GSK3β on 5Aza-induced Sca-1+ cell differentiation, make clear the regulation of MiR-155 on β-arrestin 2 and GSK3β, explore the mechanism of β-arrestin2 promoting GSK3β phosphorylation and inducing deferentiation, and then use β-arrestin2 transgenic mice and ischemia reperfusion model to elucidate the mechanism of regulation of myocardial cell differentiation in Sca-1. Our results will provide new experimental evidence for elucidating the regulatory mechanism of Sca-1+ differentiating into myocardial cell, provide new targets and clues for the prevention and treatment of heart disease.

Sca-1+ 心脏干细胞（CSCs）因可分化为心肌细胞,而具备用于心脏病治疗的潜能，但其分化的调控机制尚不明确。β-arrestin2（Arrb2）是重要的支架蛋白，在心脏中高表达。我们的预实验发现，Arrb2是5氮胞苷（5Aza）诱导Sca-1+ CSCs向心肌分化的关键因子，该过程伴随miR-155的下降和GSK3β的磷酸化失活。基于该预实验结果和文献报道，我们假设miR-155/Arrb2/GSK3β通路介导Sca-1+细胞的心肌分化。本项目将进一步明确miR-155和GSK3β在Sca-1+ CSCs心肌分化中的作用，确定miR155对Arrb2及GSK3β的调控，探讨Arrb2促进GSK3β磷酸化诱导分化的机制，并利用小鼠缺血再灌注模型研究该通路在体内Sca-1+向心肌细胞分化中的作用，为阐明Sca-1+向心肌细胞分化的调控机理提供新的实验证据，为心脏病的防治提供新靶点和线索。

Sca-1+ 心脏干细胞（CSCs）因可分化为心肌细胞,而具备用于心脏病治疗的潜能，但其分化的调控机制尚不明确。本项目利用5aza诱导心脏干细胞向心肌细胞分化的模型，明确了miR-155和GSK3β在Sca-1+ CSCs心肌分化中的作用，确定了miR155对Arrb2及GSK3β的调控，探讨了Arrb2促进GSK3β磷酸化诱导分化的机制，并利用小鼠缺血再灌注模型研究该通路在体内Sca-1+向心肌细胞分化中的作用。在此基础上，报道了新的干细胞分化诱导剂，并找到了心脏干细胞向心肌细胞分化的新通路。由于干细胞治疗的效率除了与分化有关，与其在缺氧环境下的存活与凋亡也有关，该项目对分化通路里面的关键因子在干细胞凋亡中的作用也进行了探讨，本项目研究结果为阐明Sca-1+向心肌细胞分化的调控机理提供新的实验证据，为心脏病的防治了提供新靶点和线索。