Molecular mechanisms of cerebellar ontogeny

哺乳动物的大脑由数百万到数十亿个神经元组成，这些神经元形成数十亿个复杂的连接来调节身体功能和行为。一般来说，神经元并不是出生在它们合适的地方，而是必须长途旅行（迁移）才能找到它们的最终目的地，然后才能执行它们的基本功能。为了到达目的地，他们需要在外部信号的引导下坚持正确的道路（基底）。沿着，它们也会与不同的伙伴相互作用，如胶质细胞，这有助于迁移过程。该提案旨在了解神经元如何与其环境相互作用，以选择正确的道路并找到其最终位置，重点关注称为小脑的大脑区域的发展，这对于运动协调和精确的运动执行至关重要。实验计划包括使用小鼠（一种广泛使用的哺乳动物发育模型）进行遗传实验，以研究在细胞粘附中具有重要作用的蛋白质家族（Cas家族）如何参与小脑回路的建立。拟议的研究将联合收割机小鼠遗传学与新的成像技术相结合，以解决这些蛋白质如何帮助神经元和神经胶质细胞在神经迁移过程中解释外部信号。预计这些实验的结果将提供独特的见解神经回路的发展和某些神经发育障碍的病因。教育和推广计划将通过促进高中生和本科生早期接触神经发育的实践研究来提高STEM职业的招聘和保留。小脑的简单层状结构和主要的出生后发育使其成为理解指导神经元迁移和分层的细胞机制的高度易处理的模型。迁移和分层为功能性神经回路的组装提供了基础。在这些早期发育过程中，神经元和放射状胶质细胞积极相互作用，并与细胞外基质（ECM）。这些过程涉及精确和及时地调节神经细胞与其基质的粘附和分离。初步的体内功能丧失研究确定了Crk相关底物（Cas）衔接蛋白作为小脑发育的核心参与者：Cas基因消融导致严重的分层表型。已知Cas蛋白在粘附信号传导的下游起作用，并且Cas蛋白的差异磷酸化调节整联蛋白粘附复合物（IAC）动力学。因此，Cas蛋白功能的研究提供了一个独特的机会，以了解如何调制的细胞附着到其基板参与小脑电路的形成。驱动假说是Cas衔接蛋白通过调节IAC重塑在小脑层压和叶状过程中发挥重要作用。任务1使用Cas三重条件敲除来测试Cas衔接蛋白在小脑发育期间的作用。任务2利用这些小鼠模型来研究Cas基因是否通过自主作用于神经元或自主作用于神经胶质来参与小脑分层和叶状。任务3测试的假设，Cas功能的调节控制小脑个体发育的关键步骤，通过参与IAC的动力学。该教育计划将整合课程作业和动手本科生研究中的拟议实验。该奖项反映了NSF的法定使命，并已被认为是值得通过使用基金会的智力价值和更广泛的影响审查标准进行评估的支持。

The mammalian brain is composed of millions to billions of neurons that form several billions of intricate connections to regulate bodily functions and behavior. Generally, neurons are not born in their proper place, but must travel (migrate) long distances to find their final destination before they can carry out their essential functions. To get to their destination they need to adhere to the proper road (substrate) while being guided by external signals. Along their way they will also interact with different partners, like glial cells, that aid in the process of migration. This proposal is aimed at understanding how neurons interact with their environment to choose the proper road and find their final location focusing on the development of a brain region called the cerebellum, which is essential for movement coordination and precise movement execution. The experimental plan involves performing genetic experiments using the mouse, an extensively used mammalian development model, to investigate how a family of proteins with important roles in cell adhesion (Cas family) participates in the establishment of cerebellar circuits. The proposed studies will combine mouse genetics with novel imaging techniques to address how these proteins help neurons and glia interpret external signals during neural migration. It is anticipated that the results from these experiments will provide unique insights into neuronal circuit development and the etiology of certain neurodevelopmental disorders. The educational and outreach program will improve STEM-career recruitment and retention by promoting early exposure of high school and undergraduate students to hands-on research in neural development.The simple laminar architecture and largely postnatal development of the cerebellum make it a highly tractable model for understanding the cellular mechanisms that direct neuronal migration and lamination. Migration and lamination provide a foundation upon which functional neural circuits can be assembled. During these early developmental events, neurons and radial glia actively interact with each other and the extracellular matrix (ECM). These processes involve the precise and timely regulation of adhesion and detachment of neural cells from their substrates. Preliminary in vivo loss-of-function studies identify Crk-Associated Substrate (Cas) adaptor proteins as central players in cerebellar development: Cas gene ablation results in severe lamination phenotypes. Cas proteins are known to act downstream of adhesion-signaling, and differential phosphorylation of Cas proteins regulates Integrin Adhesion Complex (IAC) dynamics. Thus, the study of Cas protein function provides a unique opportunity to understand how modulation of the attachment of cells to their substrates participates in cerebellar circuit formation. The driving hypothesis is that Cas adaptor proteins play essential roles during cerebellar lamination and foliation by regulating IAC remodeling. Task 1 uses Cas triple conditional knockouts to test the roles of Cas adaptor proteins during cerebellar development. Task 2 leverages these mouse models to investigate whether Cas genes participate in cerebellar lamination and foliation by acting neuronal-autonomously or glial-autonomously. Task 3 tests the hypothesis that regulation of Cas function controls key steps in cerebellar ontogeny by participating in IAC dynamics. The education plan will integrate the proposed experiments in coursework and hands-on undergraduate research.This award reflects NSF's statutory mission and has been deemed worthy of support through evaluation using the Foundation's intellectual merit and broader impacts review criteria.