Molecular mechanisms of cerebellar ontogeny

小脑个体发育的分子机制

• 批准号: 2235566
• 负责人: Martin Riccomagno
• 金额: $ 85万
• 依托单位: University of California-Riverside
• 依托单位国家: 美国
• 项目类别: Continuing Grant
• 财政年份: 2023
• 资助国家: 美国
• 起止时间: 2023-04-15 至 2028-03-31
• 项目状态: 未结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=2235566&HistoricalAwards=false
• 关键词: Molecular; mechanisms; cerebellar; ontogeny

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.

哺乳动物的大脑由数百万到数十亿个神经元组成，这些神经元形成了数十亿个复杂的连接，以调节身体功能和行为。一般来说，神经元并不是在适当的地方出生的，而是必须长途跋涉(迁移)找到它们的最终目的地，才能执行它们的基本功能。为了到达目的地，它们需要在外部信号的指引下坚持正确的道路(底物)。在这个过程中，它们还会与不同的伙伴相互作用，比如帮助迁移过程中的神经胶质细胞。这项建议旨在了解神经元如何与环境相互作用，选择合适的道路，并找到自己的最终位置，重点是大脑区域的发展，称为小脑，这是至关重要的运动协调和精确的运动执行。实验计划包括使用小鼠进行遗传学实验，这是一种广泛使用的哺乳动物发育模型，以研究在细胞黏附中具有重要作用的一系列蛋白质(Cas家族)如何参与小脑回路的建立。拟议的研究将结合小鼠遗传学和新的成像技术，以解决这些蛋白质如何帮助神经元和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为神经元回路发育和某些神经发育障碍的病因提供独特的见解。这项教育和推广计划将通过促进高中生和本科生及早接触神经发展方面的实践研究来改善STEM职业招聘和留住。简单的层状结构和主要是出生后小脑的发育使其成为理解指导神经元迁移和层叠的细胞机制的高度易处理的模型。迁移和层叠为组装功能神经电路提供了基础。在这些早期发育事件中，神经元和放射状胶质细胞积极地相互作用，并与细胞外基质(ECM)相互作用。这些过程包括精确和及时地调节神经细胞从其底物上的黏附和分离。初步的体内功能丧失研究发现，Crk相关底物(Cas)接头蛋白是小脑发育的核心角色：CAS基因去除会导致严重的层状表型。已知CAS蛋白作用于黏附信号的下游，而Cas蛋白的差异磷酸化调节整合素黏附复合体(IAC)的动态。因此，对CaS蛋白功能的研究提供了一个独特的机会来理解细胞附着在其底物上的调制如何参与小脑回路的形成。驱动假说是，Cas接头蛋白通过调节Iac重塑，在小脑分层和叶化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适配器蛋白在小脑发育中的作用。任务2利用这些小鼠模型来研究Cas基因是否通过神经元自主或神经胶质自主作用参与小脑的分层和叶化。任务3验证了这样的假设，即Cas功能的调节通过参与IAC动力学来控制小脑个体发育的关键步骤。该教育计划将把拟议的实验整合到课程作业和实践的本科研究中。这一奖项反映了NSF的法定使命，并通过使用基金会的智力优势和更广泛的影响审查标准进行评估，被认为值得支持。

项目成果

An adhesion signaling axis involving Dystroglycan, β1-Integrin, and Cas adaptor proteins regulates the establishment of the cortical glial scaffold.

• DOI: 10.1371/journal.pbio.3002212
• 发表时间: 2023-08
• 期刊: PLOS BIOLOGY
• 影响因子: 9.8
• 作者: Wong, Wenny;Estep, Jason A.;Treptow, Alyssa M.;Rajabli, Niloofar;Jahncke, Jennifer N.;Ubina, Teresa;Wright, Kevin M.;Riccomagno, Martin M.
• 通讯作者: Riccomagno, Martin M.