自噬对胚胎脑发育及神经干细胞的调控作用及机制研究

Brain is the central hub of human beings and the development of brain affect human intelligence and health. Brain development and neural stem cell proliferation and differentiation research will not only have important implications to understand neural development mechanism, but also have profound significance for the studies of neurological disease and regenerative medicine. Neural stem cells are non-specialized cells capable of maintaining the stem cell state and differentiating into different types of neurons and astrocytes. Autophagy is a lysosomal degradation pathway that involved in recycling long-lived proteins and cytoplasmic organelles. Autophagy is necessary for the body and organ development. However, it is largely unknown whether autophagy affects proliferation and differentiation of embryonic neural stem cell during brain development. Therefore, in this proposal, we will investigate the role of autophagy during brain development and neural stem cell. The specific aims for this proposal are 1) to check autophagy level and autophagy related protein Atg5 expression level; 2) to employ strategies of knock-down and over-express Atg5 in vitro through virus infection or in vivo through embryo electroporation and discover the phenotype of Atg5 knock-out mice to observe whether it is involved in the regulation of neural stem cell; 3) to uncover the signaling pathway of Atg5 and investigate rescue experiments. This research will increase the understanding of the role of autophagy in neural stem cells during the process of nervous system development. Furthermore, the research will provide theoretical implications for neural stem cells used in neurodegenerative diseases and disorders treatment.

脑是人类中枢调控枢纽，脑发育正常与否直接影响人类的智力和健康。胚胎脑发育和神经干细胞的增殖分化研究，不但对理解脑发育机制具有重要理论意思，也对临床研究和应用产生深远影响。发育过程中神经干细胞经历增殖和分化，产生神经元等大量形态和功能各异的细胞类型，神经干细胞在这一过程中是如何被调控的始终是发育领域的研究热点。自噬对正常的个体发育非常重要，但自噬在早期脑发育过程中如何调控神经干细胞增殖和分化不是很清楚。本课题将重点研究在神经系统发育过程中自噬及Atg5对胚胎神经干细胞增殖与分化的作用及调控机制。前期芯片结果表明自噬相关基因在脑发育过程中具有显著变化，本项目将采用体外培养原代干细胞和体内胚胎电转方法，沉默或过表达自噬特异基因Atg5，敲除Atg5后小鼠的的表型分析；另外采用恢复实验深入研究自噬相关信号通路。通过本研究将增加对自噬在神经系统发育过程中功能的认识，同时为神经系统疾病治疗提供参考。

大脑神经发育要经历神经干细胞分化为神经元和神经胶质细胞等各种特异类型的神经细胞，最终形成一个复杂的功能神经网络。大脑发育异常可导致智力低下等多种精神疾病。自噬对正常的个体发育非常重要，但自噬在早期脑发育过程中如何调控神经干细胞增殖和分化不是很清楚。我们首次发现自噬及Atg5在神经干细胞分化为神经细胞的过程中起到至关重要的作用。自噬缺陷的脑发育不正常，神经细胞分化不能很好的完成。通过过表达Atg5可以很好的修复由于自噬缺陷导致的细胞发育异常。我们进一步发现自噬通过吞噬SOCS2蛋白影响JAK/STAT信号通路，从而最终调控细胞的分化。这些基础研究成果将为进一步了解自噬在人脑发育的作用，自噬缺陷导致脑疾病及如何治疗提供重要参考。我们还发现表观修饰对脑发育的新机制。