Functional analysis of the Schizophrenia and Autism Spectrum Disorder gene TCF4 i

精神分裂症和自闭症谱系障碍基因 TCF4 i 的功能分析

基本信息

批准号：
8889789
负责人：
BRADY J MAHER
金额：
$ 45.75万
依托单位：
LIEBER INSTITUTE, INC.
依托单位国家：
美国
项目类别：
财政年份：
2014
资助国家：
美国
起止时间：
2014-08-15 至 2016-07-31
项目状态：
已结题

来源：
https://reporter.nih.gov/project-details/8889789
关键词：
Acute Architecture Autistic Disorder Autopsy Biological Brain Cell model Cellular Assay Cellular biology Chronic Clinical Complex Cortical Column Data Defect Development Diagnosis Disease Disease model Down-Regulation Electrophysiology (science)Electroporation Ephrins Etiology Exons Frequencies Functional disorder Genes Genetic Genetic Risk Genetic Transcription Goals Health Image Immigration In Vitro Individual Ion Channel Medial Mental disorders Modeling Molecular Neurodevelopmental Disorder Neurons Outcome Pathogenesis Pathway interactions Patients Pattern Phenocopy Phenotype Physiological Physiology Platelet Factor 4 Population Prefrontal Cortex Process Protein Isoforms Proteins Public Health Pyramidal Cells RNA Sequences RNA Splicing Radial Rattus Recombinants Research Risk Rodent Rodent Model Schizophrenia Signal Transduction Slice Syndrome System Techniques Testing Transcript Variant Wit autism spectrum disorder base chromosome 18q deletion syndrome data modeling gene function genetic association genetic risk factor genome wide association study human RNA sequencing in utero in vivo innovation insight migration molecular imaging neurodevelopment neuron development novel novel therapeutics programs research study risk variant sensor therapeutic development therapeutic target therapy design transcription factor treatment strategy

项目摘要

DESCRIPTION (provided by applicant): Neurodevelopmental disorders including Schizophrenia and Autism are chronic and debilitating, with relatively unknown etiology and pathophysiology. Recent progress towards understanding the genetic architecture of these disorders at the population level has led to the identification of many genetic risk factors. However, in most cases the molecular mechanism of risk and the relevant functions of the identified genes are not known and therefore identifying therapeutic targets remains difficult. In our proposal we have outlined a roadmap for the identification of therapeutic targets for psychiatric disorders and provide preliminary data that suggests our approach has merit. We will start by creating a testable cellular model of risk by genetically manipulating the expression of the schizophrenia and autism spectrum disorder gene TCF4 using in utero electroporation of the developing rat prefrontal cortex (PFC). We will then characterize the resulting neuronal phenotypes using acute brain slice electrophysiology, cell biology, and Ca2+ imaging. Such phenotypes will be evaluated as potentially pathophysiological and the development of therapeutic treatments will be based on our emerging understanding of the molecular mechanism responsible and by validating these mechanisms with molecular and pharmacological rescue or phenocopying. In Aim1, we hypothesize that TCF4 transcriptionally regulates the expression of ion channels genes that are necessary for normal neuronal physiology and in particular channels and/or Ca2+ sensors that underlie the afterhyperpolarization (AHP). Our preliminary data suggest that in utero knockdown of TCF4 in PFC layer 2/3 pyramidal cells results in abnormal intrinsic excitability and ectopic spike-frequency adaptation. We show the mechanisms of these phenotypes are associated with an increase in the AHP and are rescued by decreasing Ca2+ influx. We propose experiments to more specifically identify the mechanisms responsible. In Aim 2, we show that over-expression of TCF4 results in neuronal migration defects and the formation of abnormal cortical microcolumns in the developing PFC. We provide preliminary data that suggests these phenotypes may involve abnormal Eph/ephrin signaling and we hypothesize that accelerated neuronal migration will augment the development of intrinsic excitability and consequently disrupt the neuron's ability to integrate into the surrounding circuit. In Aim 3, we provide novel RNA sequencing data from postmortem brains of schizophrenia patients and controls that identifies a specific 5' exon of TCF4 that is differentially expressed by diagnosis, associated wit GWAS positive SNPs in TCF4, and is unique to a single TCF4 isoform (TCF4H). We propose to apply this new information to our roadmap by altering TCF4H expression in utero to more effectively model schizophrenia risk and provide additional validity to cellular models. We think these innovative approaches will enable us to provide significant insights into the etiology and pathophysiology of these disorders and will ultimately open doors to novel therapeutic treatments.

描述（由申请人提供）：包括精神分裂症和自闭症在内的神经发育障碍是长期且令人衰弱的，具有相对未知的病因和病理生理学。在人口水平上了解这些疾病的遗传结构的最新进展导致了许多遗传危险因素的识别。但是，在大多数情况下，尚不清楚鉴定基因的风险和相关功能的分子机制，因此鉴定治疗靶标仍然很困难。在我们的提案中，我们概述了识别精神疾病治疗靶标的路线图，并提供了表明我们方法有价值的初步数据。我们将通过遗传操纵精神分裂症和自闭症谱系障碍障碍基因TCF4的表达来创建可检验的风险细胞模型。然后，我们将使用急性脑切片电生理学，细胞生物学和Ca2+成像来表征所得的神经元表型。这种表型将被评估为潜在的病理生理学，并且治疗治疗的发展将基于我们对负责的分子机制的新兴理解，并通过通过分子和药理拯救或现场验证来验证这些机制。在AIM1中，我们假设TCF4转录调节了正常神经元生理学所必需的离子通道基因的表达，以及尤其是基于毕竟的辉光（AHP）的通道和/或Ca2+传感器。我们的初步数据表明，在PFC层2/3锥体细胞中TCF4的子宫内敲低中，会导致异常的内在兴奋性和异位尖峰频率适应。我们显示这些表型的机制与AHP的增加有关，并通过减少Ca2+流入来挽救。我们提出实验，以更具体地确定负责的机制。在AIM 2中，我们表明TCF4的过表达导致神经元迁移缺陷和发育中的PFC中异常皮质微柱的形成。我们提供了初步数据，表明这些表型可能涉及异常的EPH/Ephrin信号传导，我们假设加速的神经元迁移将增加内在兴奋性的发展，从而破坏神经元在周围电路中整合的能力。在AIM 3中，我们提供了来自精神分裂症患者后脑大脑的新型RNA测序数据，并提供了识别特定5'外显子TCF4外显子的对照，该数据是通过诊断差异表达的，TCF4中与wit gwas阳性SNP差异表达，并且是单个TCF4同工型（TCF4H）所独有的。我们建议通过改变子宫中的TCF4H表达来将这些新信息应用于我们的路线图，以更有效地对精神分裂症的风险进行建模，并为细胞模型提供额外的有效性。我们认为，这些创新的方法将使我们能够对这些疾病的病因和病理生物生物生物学提供重大见解，并最终为新颖的治疗治疗敞开大门。