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种人类神经系统疾病有关，包括癫痫、精神分裂症、自闭症和智力迟钝。皮层层是由神经元从增殖区迁移到发育中的皮层壁形成的。因此，了解神经元迁移是如何被调节的，对于阐明神经元层形成的机制至关重要，并可能提供与几种神经系统疾病相关的病理变化的见解。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，我在这里建议研究reelin控制皮层细胞层形成的机制。我的建议的中心假设是，reelin针对的是RGCs和迁移神经元的不同细胞功能，这些功能最终控制皮层层压。为了验证这一假设，将追求以下具体目标：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)基于CRE/LOX重组、siRNA表达和子宫内基因转移，在不影响神经元信号的情况下，干扰RGC中的reelin信号传导；（ii）利用实时成像技术，确定RGC过程生长和附着中因reelin信号失活而导致的细胞自主缺陷；（iii）确定RGC缺陷继发影响皮质神经元迁移的程度。（iv）参与reelin信号传导的靶细胞表面受体，以确定其在RGC功能中的作用。目的2：确定reelin控制皮层神经元迁移行为的机制。实现这一目标的建议方法是：(i)使用类似于Aim 1中描述的策略，选择性地灭活迁移神经元中的reelin信号，并研究对其行为的影响，如运动性、极性发育和染色体易位；（ii）开发适合于对早期或晚期出生神经元中的reelin信号进行选择性遗传扰动的突变小鼠系；（iii）测试不同迁移模式中reelin信号的灭活对皮层层压的影响程度。相关性：大脑皮层的异常发育导致超过25种不同的人类神经系统综合征，这些综合征以显著的临床症状为特征，包括癫痫、自闭症、精神分裂症和智力迟钝。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学提供重要信息。

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.