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An investigation of guidance mechanisms regulating neuronal migration

调节神经元迁移的引导机制的研究

基本信息

批准号：
8475633
负责人：
Sarah J. Wanner
金额：
$ 5.94万
依托单位：
UNIVERSITY OF CHICAGO
依托单位国家：
美国
项目类别：
财政年份：
2011
资助国家：
美国
起止时间：
2011-07-01 至 2014-06-30
项目状态：
已结题

项目摘要

DESCRIPTION (provided by applicant): This project is focused on understanding the molecular and cellular basis of neuronal migration. Many types of neurons undergo migration to reach their appropriate destination by responding to both contact-dependent and contact-independent signals; aberrant neuronal migration underlies a variety of birth defects. Neuronal migration is influenced by cell adhesion molecules, which play a dual role allowing neurons to engage in cellular interactions that influence migration as well as regulating signaling mechanisms important for the outgrowth and guidance of neural projections. Preliminary experiments have shown that N-cadherin (Ncad), a prominent cell adhesion molecule in the nervous system, is required for facial branchiomotor neuron (FBMN) migration. The experiments outlined in this proposal aim to test the overarching hypothesis that Ncad is required for FBMN migration by modulating both adhesion-dependent interactions and the response to molecular guidance cues within the hindbrain environment. In Aim 1 a detailed analysis of neuronal migratory behavior in Ncad-deficient embryos will be performed using live imaging to explore how Ncad regulates FBMN migration and guidance. Further, cell transplantation will test whether Ncad functions autonomously or non-autonomously in FBMNs to mediate their migration. In preliminary experiments I find Ncad- depletion arrests FBMN migration and some neurons aberrantly migrate into the midline, suggesting an attractant midline cue guides FBMN migration. Aim 2 will test the hypothesis that Ncad modulates FBMN response to the molecular guidance cue SDF1a. This will be accomplished by using ectopic localization of SDF1a in wild type and Ncad-deficient embryos to test the ability of SDF1a to act as an attractant cue to FBMNs and to examine the role of Ncad in modulating the response of FBMNs to SDF1a. Lastly, another means of providing directional cues to neurons is through following pre-laid axon tracts, which relies upon the formation of cellular adhesions between neurons and the axon tract. Aim 3 will test the hypothesis that Ncad is required for adhesion-dependent interactions between the FBMNs and the medial longitudinal fascicle (MLF) to facilitate FBMN migration. To examine the dynamic interaction between facial neurons and the MLF I will utilize immuno- fluorescence and time-lapse microscopy in wild type and Ncad-deficient embryos. I will also investigate the importance of the MLF in facial neuron guidance by removing the MLF using surgical manipulations. These experiments will test the importance of Ncad in regulating adhesion-dependent interactions between FBMNs and the MLF. Together the aims of this proposal will determine the role of Ncad in neuronal migration and guidance and add to our understanding of how neuronal migration is regulated.

描述（由申请人提供）：该项目的重点是了解神经元迁移的分子和细胞基础。许多类型的神经元通过响应接触依赖性和接触无关信号进行迁移以到达适当的目的地；异常的神经元迁移是多种出生缺陷的基础。神经元迁移受到细胞粘附分子的影响，细胞粘附分子发挥双重作用，使神经元参与影响迁移的细胞相互作用，并调节对神经投射的生长和引导很重要的信号机制。初步实验表明，N-钙粘蛋白（Ncad）是神经系统中一种重要的细胞粘附分子，是面部鳃运动神经元（FBMN）迁移所必需的。本提案中概述的实验旨在通过调节后脑环境中粘附依赖性相互作用和对分子引导线索的反应来测试 FBMN 迁移需要 Ncad 的总体假设。在目标 1 中，将使用实时成像对 Ncad 缺陷胚胎中的神经元迁移行为进行详细分析，以探索 Ncad 如何调节 FBMN 迁移和引导。此外，细胞移植将测试 Ncad 在 FBMN 中是否自主或非自主发挥作用以介导其迁移。在初步实验中，我发现 Ncad 耗尽会阻止 FBMN 迁移，并且一些神经元异常迁移到中线，这表明中线诱因引导 FBMN 迁移。目标 2 将检验 Ncad 调节 FBMN 对分子引导信号 SDF1a 的反应的假设。这将通过在野生型和 Ncad 缺陷胚胎中使用 SDF1a 的异位定位来完成，以测试 SDF1a 作为 FBMN 引诱剂线索的能力，并检查 Ncad 在调节 FBMN 对 SDF1a 反应中的作用。最后，向神经元提供方向线索的另一种方法是遵循预先铺设的轴突束，这依赖于神经元和轴突束之间细胞粘附的形成。目标 3 将检验以下假设：FBMN 和内侧纵束 (MLF) 之间的粘附依赖性相互作用需要 Ncad 以促进 FBMN 迁移。为了检查面部神经元和 MLF 之间的动态相互作用，我将在野生型和 Ncad 缺陷胚胎中利用免疫荧光和延时显微镜。我还将通过使用外科手术去除 MLF 来研究 MLF 在面部神经元引导中的重要性。这些实验将测试 Ncad 在调节 FBMN 和 MLF 之间的粘附依赖性相互作用中的重要性。该提案的目标将共同确定 Ncad 在神经元迁移和指导中的作用，并增加我们对神经元迁移如何调节的理解。