Functions of DISC1 and APP in Cortical Development and Neuropsychiatric Disorders

描述（由申请人提供）：皮质细胞迁移缺陷与一系列表型有关，包括癫痫、精神发育迟滞、自闭症和精神分裂症（SZ）。在过去，与经典的神经元迁移疾病（如无脑回畸形）相关的人类基因的功能分析已经对迁移途径和这些疾病的根本原因产生了有价值的见解。对啮齿动物的研究为迁移所需的基因列表增加了额外的因素。一种这样的因子是淀粉样前体蛋白（APP），一种阿尔茨海默病相关基因，其是正常迁移到皮质板和神经元突起生长所需的。此外，有几个基因与精神分裂症有关，如DISC 1，PDE 4和NRG 1，所有这些基因都在神经元发育中发挥重要作用，包括迁移和神经突生长。最近的研究将涉及APOER 2，DAB 1和LIS 1等因子的经典迁移途径与APP和某些SZ相关基因联系起来。本申请旨在1）将这些新鉴定的参与者整合到已建立的迁移和神经突生长途径中; 2）阐明SZ相关基因中的某些突变和变体如何导致迁移缺陷; 3）解决迁移缺陷和/或神经元突起生长的细微变化是否导致神经递质及其受体水平改变，这两者都在SZ患者中描述。子宫内电穿孔的体内方法将用于表达编码野生型或突变形式的候选蛋白的shRNA或cDNA，以评估它们的改变的表达对胚胎大鼠脑中神经元前体迁移的影响。还将利用原代神经元培养物来分析这些不同构建体对神经元突起生长的影响。最后，神经递质受体表达（使用生物化学和免疫组织化学）和神经递质水平（使用微透析和HPLC）将在啮齿动物中进行分析，其中不同的遗传操作导致不同程度的皮质迁移紊乱。这组实验将解决神经元迁移异常与SZ患者中观察到的神经递质系统缺陷有关的假设。

DESCRIPTION (provided by applicant): Defects of cortical cell migration have been linked to a spectrum of phenotypes that include epilepsy, mental retardation, autism, and schizophrenia (SZ). In the past, functional analyses of human genes linked to classic disorders of neuronal migration such as lissencephaly have yielded valuable insights into the pathways involved in migration and the underlying causes of these diseases. Studies in rodents have added additional factors to the list of genes necessary for migration. One such factor is Amyloid Precursor Protein (APP), an Alzheimer's Disease linked gene, which is required for both normal migration into the cortical plate and neuronal process outgrowth. In addition, several genes have been linked to schizophrenia such as DISC1, PDE4, and NRG1, all of which play important roles in neuronal development, including migration and neurite outgrowth. Recent studies link classic pathways of migration involving factors such as APOER2, DAB1, and LIS1 with both APP and certain SZ-linked genes. This application aims to 1) integrate these newly identified players into established migration and neurite outgrowth pathways; 2) elucidate how certain mutations and variants in SZ-associated genes lead to defects in migration; and 3) address whether defects in migration and/or subtle alterations in neuronal process outgrowth lead to altered levels of neurotransmitters and their receptors, both of which are described in patients with SZ. The in vivo method of in utero electroporation will be used to express shRNAs or cDNAs encoding wild type or mutated versions of candidate proteins to assess the effects of their altered expression on neuronal precursor migration in the context of the embryonic rat brain. Primary neuronal cultures also will be utilized to analyze the effects of these various constructs on neuronal process outgrowth. Lastly, both neurotransmitter receptor expression (using biochemistry and immunohistochemistry) and neurotransmitter levels (using microdialysis and HPLC) will be analyzed in rodents in which different genetic manipulations have caused varying degrees of disordered cortical migration. This set of experiments will address the hypothesis that abnormalities in neuronal migration are linked to defects in the neurotransmitter systems that are observed in patients with SZ.