Mechanism and function of interkinetic nuclear migration in mouse embryonic neural stem cells

项目摘要 研究神经干细胞（NSC）如何在发育中的大脑中增殖，分化和自我组织 将导致更好地了解发育障碍的发病机制，并可能提供 对体外脑类器官培养的设计具有重要指导意义。虽然NSC增殖的机制 和分化已经被深入研究，如何在脑神经干细胞空间自组织过程中， 形态发生仍在很大程度上未被探索。在本申请中，胚胎小鼠新皮层用于 研究NSC的空间组织。在胚胎发育过程中，新皮层内的神经干细胞经历 在神经发生开始之前，在组织的内表面（即顶端表面）的有丝分裂以自扩张。 神经干细胞池的扩增与新皮层的快速向外扩张相一致。机制 内表面的有丝分裂转化为组织的向外扩张仍然很不清楚。一 PI最近的研究表明，运动间核迁移（IKNM），NSC的标志性特征， 通过会聚延伸机制促进新皮层扩张。根据这项研究， 根据初步数据，本申请提出了三个具体目标，以阐明 平面细胞极性（PCP）信号调节IKNM和新皮层形态发生。在目标A中， 提出测试两个竞争模型，PCP信号调节IKNM和新皮层 形态发生在目标B中，设计实验以检验PCP信号传导维持细胞内蛋白质水平的假设。 通过抑制YAP 1/TAZ的核定位来平衡IKNM和细胞增殖， Hippo信号和机械信号下游的细胞增殖调节因子。在目标C中，自闭症的作用 将检查IKNM依赖性新皮层形态发生中的风险基因。该应用程序将带来重大 在一个严重不足的领域，即神经干细胞的空间组织在新皮层形态发生的进展。 从这个应用程序中发现的管理NSC空间组织的基本原则可以提供 脑类器官体外培养策略的重要指导，并将自闭症风险基因与调控联系起来 在新皮层发育的早期阶段，NSC的空间组织。

PROJECT SUMMARY Investigating how neural stem cells (NSCs) proliferate, differentiate, and self-organize in the developing brain in vivo will lead to better understanding of pathogenesis of developmental disabilities, and may provide important guidance on the design of in vitro brain organoid culture. While the mechanisms of NSC proliferation and differentiation have been intensively studied, how NSCs spatially self-organize during brain morphogenesis remains largely unexplored. In this application, the embryonic mouse neocortex is used for studying NSC spatial organization in vivo. During embryonic development, NSCs within the neocortex undergo mitosis at the inner surface (i.e. apical surface) of the tissue to self-expand before the onset of neurogenesis. The amplification of the NSC pool coincides with rapid outward expansion of the neocortex. Mechanisms by which mitosis at the inner surface is converted into outward expansion of the tissue remain largely unclear. A recent study from the PI suggests that interkinetic nuclear migration (IKNM), a hallmark feature of NSCs, promotes neocortical expansion via a convergent extension mechanism. Based on this study and additional preliminary data, three Specific Aims are proposed in this application to elucidate the mechanisms by which planar cell polarity (PCP) signaling regulates IKNM and neocortical morphogenesis. In Aim A, experiments are proposed to test two competing models by which PCP signaling regulates IKNM and neocortical morphogenesis. In Aim B, experiments are designed to test the hypothesis that PCP signaling maintains the balance of IKNM and cell proliferation by inhibiting nuclear localization of YAP1/TAZ, which are master regulators of cell proliferation downstream of Hippo signaling and mechanical cues. In Aim C, the role of autism risk genes in IKNM-dependent neocortical morphogenesis will be examined. This application will bring major advancement in a severely understudied field, i.e. NSC spatial organization during neocortical morphogenesis. The basic principles governing NSC spatial organization discovered from this application may provide important guidance on strategies for in vitro culture of brain organoids, and link autism risk genes to regulation of NSC spatial organization during early stages of neocortical development.