转录因子Neurogenin在Wnt/β-catenin信号调控iPS向神经干细胞分化中作用及其机制

It is the key point to determine the molecular mechanisms during differentiation of induced pluripotent stem cells (iPS) into neural stem cells (NSC). Although our research demonstrated that iPS cells were able to differentiate into NSC, the underlying mechanisms remain unclear and the differentiation efficiency still needs to be improved. Our previous study has shown that Wnt/β-catenin signal pathway directed the neurogenetic differentiation of mesenchymal stem cells and the transcription factor Neurogenin played an important role in the process (BBRC, 2013, 439(2):297-302）. Based on aboundant previous evidence and our data, we hypothesized that Wnt/β-catenin signal might directly regulate the promoter of Neurogenin and play a key role in the neuronal differentiation of iPS cells. In this study, we will examine the role of neurogenin and Wnt/β-catenin signal pathway on the neuronal differentiation of iPS cells using gene over-expression and SiRNA assay. In addition, we will study the role of neural stem cells derived from iPS cells in the repairment of nervous injury. Our study will provide a new theoretical foundation and technical preparation for improving the efficiency of neural stem cell differentiation and promote the translation of basic research to clinic application.

分化调控机制的揭示是解决诱导性多能干细胞（iPS）分化成为功能性神经干细胞（NSC）的关键科学问题。本课题组前期研究证实Wnt/β-catenin信号通路可调控间充质干细胞向神经元分化，而神经特异性转录因子Neurogenin在其中起重要作用（BBRC,2013,439(2):297-302）。结合既往研究，我们推测Wnt/β-catenin 信号通过调控转录因子Neurogenin实现iPS 向NSC定向分化。本项目拟在前期研究基础上，通过研究上调、下调Wnt/β-catenin及Neurogenin表达对iPS向NSC分化效率与功能的影响，明确Neurogenin在Wnt/β-catenin 信号调控iPS向NSC分化中的作用；并深入探讨iPS 分化来源NSC对体内神经损伤的修复作用。本项目的研究为提高NSC分化效率、促进iPS的基础研究向临床应用转化提供一定的理论和实验依据。

分化调控机制的揭示是解决诱导性多能干细胞（iPS）分化成为功能性神经干细胞（NSCs）的关键科学问题。本项目研究了Wnt/β-catenin信号通路在iPS向NSCs分化过程中的作用及机制；研究了转录因子Neurogenin1（Ngn1）、Neurogenin2（Ngn2）、TCF1、LEF1在Wnt/β-catenin信号通路调控iPS向NSCs分化过程中的作用；探讨了Wnt/β-catenin信号通路和转录因子Ngn2对iPS分化来源NSCs移植修复缺血性脑损伤的作用。结果发现：（1）采用N2B27培养基联合RA诱导法，可诱导iPS向NSCs分化，iPS分化来源的NSCs具有增殖和分化为神经元细胞、星形胶质细胞的能力；（2）Wnt/β-catenin信号通路在iPS向NSCs分化过程中具有重要作用，通过转录因子Ngn1、Ngn2、TCF1、LEF1参与分化；（3）下调Wnt/β-catenin信号通路对iPS分化来源NSCs的增殖能力未见影响，可降低迁移能力和分化时的细胞凋亡情况，促进其向神经元细胞、星形胶质细胞分化；（4）iPS分化来源NSCs移植促进缺血性脑损伤的修复，Wnt/β-catenin信号通路及转录因子Ngn2在其过程中发挥重要作用。本项目的研究为提高NSCs分化效率、促进iPS的基础研究向临床应用转化提供一定的理论和实验依据。