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

• 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
• 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

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(申请人提供)：神经发育障碍，包括精神分裂症和自闭症，是一种慢性和衰弱的疾病，病因和病理生理学相对未知。在人口层面上了解这些疾病的遗传结构方面的最新进展导致了许多遗传风险因素的确定。然而，在大多数情况下，风险的分子机制和已识别基因的相关功能尚不清楚，因此识别治疗靶点仍然困难。在我们的提案中，我们概述了确定精神障碍治疗靶点的路线图，并提供了初步数据，表明我们的方法是有价值的。我们将首先使用发育中的大鼠前额叶皮质(PFC)的宫内电穿孔，通过遗传操作精神分裂症和自闭症谱系障碍基因TCF4的表达，创建一个可测试的风险细胞模型。然后，我们将使用急性脑片电生理学、细胞生物学和钙离子成像来表征由此产生的神经元表型。这些表型将被评估为潜在的病理生理，治疗方法的开发将基于我们对相关分子机制的新理解，并通过分子和药物救援或表型复制来验证这些机制。在Aim1中，我们假设TCF4转录调控正常神经元生理所必需的离子通道基因的表达，特别是参与后超极化(AHP)的通道和/或钙离子感受器。我们的初步数据表明，在宫内敲除PFC层2/3锥体细胞中的TCF4会导致异常的内在兴奋性和异位的尖峰频率适应。我们表明这些表型的机制与AHP的增加有关，并通过减少钙离子内流而被拯救。我们建议进行实验，以更具体地确定负责的机制。在目标2中，我们发现在发育中的PFC中，TCF4的过度表达导致神经元迁移缺陷和异常皮质微柱的形成。我们提供的初步数据表明，这些表型可能涉及异常的Eph/EPhin信号，我们假设神经元加速迁移将增强内在兴奋性的发展，从而扰乱神经元整合到周围电路的能力。在目标3中，我们从精神分裂症患者和对照组的死后脑中提供了新的RNA测序数据，该数据确定了TCF4的一个特定的5‘外显子，该外显子在TCF4中存在差异表达，与TCF4中的GWAS阳性SNPs相关，并且是单一TCF4亚型(TCF4H)所特有的。我们建议将这一新信息应用于我们的路线图，通过改变TCF4H在子宫中的表达来更有效地模拟精神分裂症的风险，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学和病理生理学提供重要的见解，并最终将为新的治疗方法打开大门。