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

项目总结 研究神经干细胞如何在发育中的大脑中增殖、分化和自组织 体内实验将有助于更好地了解发育障碍的发病机制，并可能为 对体外脑器官培养的设计具有重要指导意义。而神经干细胞增殖的机制 和分化已经被深入研究，神经干细胞在大脑中如何在空间上自组织 形态发生在很大程度上仍未被探索。在这项应用中，胚胎小鼠的新皮质用于 活体研究神经干细胞的空间组织。在胚胎发育期间，新皮质内的神经干细胞经历 在神经发生开始之前，组织内表面(即顶端表面)的有丝分裂以自我扩展。 神经干细胞池的扩大与新皮质的快速向外扩张相一致。机制，由 内表面的哪种有丝分裂转化为组织的向外扩张在很大程度上仍不清楚。一个 PI最近的研究表明，神经干细胞的一个显著特征--动间核迁移(IKNM)， 通过收敛延伸机制促进新皮质扩张。基于此研究和其他 初步数据，在这项申请中提出了三个具体目的，以阐明其机制 平面细胞极性(PCP)信号调节IKNM和新皮质的形态发生。在目标A中，实验是 建议测试PCP信号调节IKNM和新皮质的两个竞争模型 形态发生。在目标B中，实验旨在测试PCP信号维持 通过抑制YAP1/TAZ的核定位平衡IKNM和细胞增殖 河马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 将研究依赖于IKNM的新皮质形态发生中的危险基因。此应用程序将为您带来主要 在一个严重缺乏研究的领域中的进展，即新皮质形态发生过程中的NSC空间组织。 从本应用程序中发现的管理NSC空间组织的基本原则可能提供 对脑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 在新皮质发育的早期阶段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.