Mechanisms of Reelin Action on neuronal Migration During Neocortical Lamination

描述(由申请人提供)：新皮质层状结构的破坏与超过25种人类神经疾病有关，包括癫痫、精神分裂症、自闭症和智力低下。皮质层是通过神经元从增殖区迁移到发育中的皮质壁而建立的。因此，了解神经元迁移是如何调控的，对于阐明层形成的机制至关重要，并可能为了解与几种神经疾病相关的病理变化提供洞察力。我的长期目标是确定控制大脑皮层层状结构发育的机制。作为第一步，我建议在这里研究reelin控制皮质细胞层形成的机制。我的提议的中心假设是，reelin针对RGC和最终控制皮质分层的迁移神经元中不同的细胞功能。为了验证这一假设，我们将寻求以下具体的施舍：目标1：确定reelin影响RGC行为的机制。实现这一目标的建议方法是：(I)开发基于Cre/LOX重组、siRNA表达和宫内基因转移的RGC，在不影响神经元信号的情况下干扰RGC的reelin信号；(Ii)使用实时成像来确定RGC过程中由于Reelin信号失活而导致的细胞自主缺陷；(Iii)确定RGC中的缺陷在多大程度上继而影响皮质神经元的迁移；(Iv)涉及reelin信号的靶细胞表面受体，以确定它们在RGC功能中的作用。目的2：确定Reelin控制大脑皮层神经元迁移行为的机制。建议的实现这一目标的方法是：(I)使用与目标1中描述的策略类似的策略来选择性地灭活迁移神经元中的reelin信号并研究其对其行为的影响，例如运动性、极性的发育和胞体易位，(Ii)建立适合于选择性遗传扰动早期或晚出生神经元中的reelin信号的突变小鼠系，(Iii)测试在不同迁移模式下reelin信号的失活对皮质层的影响程度。相关：大脑皮层发育异常导致超过25种不同的人类神经综合征，这些综合征的特征是显著的临床症状，包括癫痫、自闭症、精神分裂症和智力低下。因此，了解大脑皮层在大脑发育过程中是如何形成的，有望为这些疾病的病理提供重要信息。

DESCRIPTION (provided by applicant): Disruption of the laminar architecture of the neocortex is associated with more than 25 human neurological disorders, including epilepsy, schizophrenia, autism and mental retardation. Cortical layers are established by the migration of neurons from proliferative zones into the developing cortical wall. Thus, knowledge of how neuronal migration is regulated is critical for elucidating the mechanisms by which layer formation is achieved, and will likely provide insights into the pathological changes associated with several neurological disorders. My long-term objective is to define the mechanisms that control development of the laminar structure of the cerebral cortex. As a first step, I propose here to study the mechanisms by which reelin controls the formation of cortical cell layers. The central hypothesis of my proposal is that reelin targets distinct cellular functions in RGCs and migrating neurons that ultimately control cortical lamination. To test this hypothesis, the following specific alms will be pursued: Aim 1: Determine the mechanisms by which reelin affects RGC behavior. The proposed methods for achieving this goal are: (i) develop based on CRE/LOX recombination, siRNA expression and in utero gene transfer to perturb reelin signaling in RGCs without affecting signaling to neurons, (ii) use real-time imaging to determine the cell-autonomous defects in RGC process outgrowth and attachment that result from inactivation of reelin signaling, (iii) determine the extent to which defects in RGCs secondarily affect migration of cortical neurons, (iv) target cell-surface receptors implicated in reelin signaling to determine their roles in RGC function. Aim 2: Determine the mechanism by which reelin controls the migratory behavior of cortical neurons. The proposed methods for achieving this goal are: (i) use strategies similar to those described in Aim 1 to selectively inactivate reelin signaling in migrating neurons and study effects on their behavior, such as motility, development of polarity and somal translocation, (ii) developed mutant mouse lines suitable for selective genetic perturbation of reelin signaling in early- or late-born neurons, (iii) test the extent to which inactivation of reelin signaling during different modes of migration affects cortical lamination. Relevance: Abnormal development of the cerebral cortex causes more than 25 different human neurological syndromes that are characterized by significant clinical symptoms, including epilepsy, autism, schizophrenia and mental retardation. Therefore, understanding how the cerebral cortex is formed during development of the brain is expected to provide important information on the pathology of these diseases.