Role of Cdc42 and Par6 Polarity Complex in CNS Neuronal Migration

Cdc42 和 Par6 极性复合物在 CNS 神经元迁移中的作用

• 批准号: 8627650
• 负责人: Mary Elizabeth Hatten
• 金额: $ 36.6万
• 依托单位: ROCKEFELLER UNIVERSITY
• 依托单位国家: 美国
• 财政年份: 2006
• 资助国家: 美国
• 起止时间: 2006-08-02 至 2016-02-28
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/8627650
• 关键词: Adhesions; Affect; Architecture; Autistic Disorder; Biological Models; Brain; Brain Diseases; Brain region; Cell Adhesion Molecules; Cell Nucleus; Cell Polarity; Cells; Centrosome; Chimeric Proteins; Code; Complex; Computer software; Cortical Malformation; Cre-LoxP; Cytoplasmic Granules; Development; Diagnosis; Disease; Epilepsy; Exhibits; Extracellular Domain; Fiber; Fluorescence Resonance Energy Transfer; Genetic; Goals; Grant; Health; Human; Image; Immigration; Integrins; Life; LoxP-flanked allele; Maintenance; Mental Retardation; Molecular; Monitor; Motor; Movement; Mus; Myosin ATPase; Neuroglia; Neuronal Migration Disorder; Neurons; PHluorin; Pathway interactions; Pattern; Phenotype; Positioning Attribute; Process; Protein Binding; Protein Isoforms; Proteins; Relative (related person); Reporter; Research; Resolution; Role; Signal Pathway; Surface; Synapses; System; Takeda brand of pioglitazone hydrochloride; Testing; Time; Tubulin; adhesion receptor; axon guidance; base; cdc42 GTP-Binding Protein; cell motility; cell type; granule cell; insight; interstitial; loss of function; migration; mutant; neuronal cell body; progenitor; receptor; reconstruction; research study; spatiotemporal; trafficking

DESCRIPTION (provided by applicant): The development of the mammalian brain depends on the migrations of neuronal precursors from germinal zones, where they are generated, and their assembly into neuronal laminae, where synaptic connections form. Since CNS migration disorders are associated with a number of cortical malformations, and are a major cause of disease in the developing human brain, including mental retardation and epilepsy, a clearer understanding of the molecular control of CNS neuronal migration could be relevant to the diagnosis and treatment of human developmental brain disorders. Neuronal migration critically depends on the polarization of the neuron in the direction of moment, and with support from this grant, we previously established that the conserved mPar61 polarity complex localizes to the centrosome and coordinates the forward movement of the centrosome and soma, by a mechanism that includes activation of acto-myosin contractile motors in the proximal region of the leading process, in migrating cerebellar granule neurons. The overall goal of the proposed research is to define the relative contributions of the master polarity regulator Cdc42 and the three Par6 isoforms to critical steps in CNS migration, including the formation and maintenance of a highly polarized leading process, and to define their role(s) in receptor trafficking of neuronal adhesion proteins. Although a clear role for Cdc42 has been established in the migration of many non-neuronal cells, and in dendritic arborization and axon guidance, the roles of Cdc42 and the relative role of the Par6 isoforms have not been analyzed in high-resolution time-lapse imaging of live, migrating CNS neurons. Given the importance of glial-guided migration to the formation of neuronal layers in cortical regions of brain, we will focus on this highly specialized migration system, using cerebellar granule neurons migrating on glia as our model system. In Aim 1, we will study a conditional loss of function of Cdc42; a similar plan will be implemented in Aim 3 for each of the three Par6 isoforms expressed in granule cell progenitors (GCPs). As a complementary approach, in Aims 2 & 3, we will use siRNAs and shRNAs to knockdown Cdc42 and Par6 isoform levels and compare knockdown phenotypes with conditional loss of function phenotypes. If Cdc42 is in the same genetic pathway with any or all of the Par6 isoforms, we would expect to see similar phenotypes for Cdc42 and Par6 isoform loss of function. We will also use Raichu probes for Cdc42, kindly provided by Dr. Miki Matsuda, which are FRET-based probes that monitor Cdc42 activation in localized regions of a cell. These probes will enable us to evaluate the spatiotemporal localization of Cdc42 activation relative to the Par6 isoforms in migrating GCPs. The discovery of changing patterns of Par6 expression during cerebellar development is an exciting opportunity to understand their relative contributions to neuronal migration and whether they act within a Cdc42 signaling pathway.

描述（由申请人提供）：哺乳动物大脑的发育取决于从生成的生发区域的神经元前体的迁移，以及它们的组装到神经元层中，突触连接形成。由于中枢神经系统的迁移障碍与多种皮质畸形有关，并且是发展中大脑的主要原因，包括智力低下和癫痫，因此对CNS神经元迁移的分子控制的更清晰了解可能与人类发育障碍的诊断和治疗有关。神经元迁移在关键上取决于神经元沿瞬间的极化，在这笔赠款的支持下，我们先前确定，保守的MPAR61极性复合物定位于中心体，并协调中心体和躯体的前进运动，包括通过在侵蚀剂中迁移的机制，该机制在跨乳糖素的迁移过程中迁移，该机制是元素的迁移范围，该方案是元素的迁移范围。神经元。拟议研究的总体目标是确定主要极性调节剂CDC42和三种PAR6同工型对中枢神经系统迁移的关键步骤的相对贡献，包括形成和维护高度极化的领导过程，并确定其在神经粘附蛋白受体运输中的作用。尽管在许多非神经元细胞的迁移中已经确定了CDC42的明显作用，并且在树突状树皮化和轴突指导中，cdc42的作用和PAR6同工型的相对作用尚未在高分辨率的现场迁移时迁移CNS神经元中分析。鉴于神经胶质引导迁移到大脑皮质区域中神经元层的形成的重要性，我们将使用小脑颗粒神经元作为模型系统的小脑颗粒神经元来关注这个高度专业化的迁移系统。在AIM 1中，我们将研究CDC42功能的有条件丧失。对于在颗粒细胞祖细胞（GCP）中表达的三种PAR6同工型中的每一个中的每一个，将在AIM 3中实施类似的计划。作为一种互补方法，在目标2和3中，我们将使用siRNA和SHRNA进行敲低CDC42和PAR6同工型水平，并比较敲低表型与功能表型的条件丧失。如果CDC42在任何或全部PAR6同工型中处于相同的遗传途径中，我们希望看到CDC42和PAR6同工型功能损失相似的表型。我们还将使用Miki Matsuda博士提供的cdc42探针，该探针是基于FRET的探针，可监测细胞局部区域中的Cdc42激活。这些探针将使我们能够评估Cdc42激活相对于迁移GCP中PAR6同工型的时空定位。小脑发育过程中PAR6表达的变化模式的发现是一个令人兴奋的机会，可以理解其对神经元迁移的相对贡献，以及它们是否在CDC42信号通路中起作用。