Molecular and Behavioral Neurobiology of Transcription Factor TCF4

描述（由申请人提供）：基本的螺旋-环-螺旋转录因子TCF4（又名E2-2）广泛涉及人类中枢神经系统功能。TCF4在几项大型GWAS研究中被证实是一种罕见的高度复制的精神分裂症易感基因，当单倍体不足时，TCF4是皮特-霍普金斯综合征（PTHS）的致病因素。PTHS在人类认知功能方面具有引人注目的特征，与明显的记忆缺陷，自闭症行为，以及重要的几乎完全缺乏语言发展有关。因此，了解TCF4在中枢神经系统中的作用和功能对于人类语言和听觉认知、记忆功能、自闭症谱系行为和精神分裂症易感性具有重要意义。尽管TCF4在人类中枢神经系统中的功能非常重要，但对TCF4的基本神经生物学研究却很少。因此，本项目将使用基因工程小鼠模型来评估TCF4在记忆、社会互动和交流、海马突触可塑性、突触解剖以及中枢神经系统表观基因组和转录调控中的作用。提出的研究的中心假设是，TCF4通过积极调节响应行为经验的转录活性来调节大脑触发长期突触可塑性和记忆形成的能力。该方法将使用生殖系组成敲除和成年小鼠海马中TCF4的急性敲除或缺失，结合广泛的行为、电生理和转录组/表观基因组特征，来确定TCF4功能是否对成熟中枢神经系统的正常记忆和突触可塑性是必要的。这些研究不仅将利用现有的种系敲除系，还将利用已有的floxed TCF4等位基因小鼠系，并将这些小鼠与成年海马中病毒驱动的cre表达和发育后CaMKII启动子驱动的前脑神经元选择性cre表达结合起来，在体内实现可诱导的发育后CNS TCF4功能的衰减。使用这些新颖的小鼠模型，我们将进行三个具体的目标。Aim 1将验证tcf4缺陷小鼠表现出认知记忆和社会互动缺陷的假设，并验证tcf4缺陷小鼠表现出突触可塑性改变的假设。目标2将包括一个重要的翻译

DESCRIPTION (provided by applicant): The basic helix-loop-helix transcription factor TCF4 (aka E2-2) has been implicated broadly in human CNS function. TCF4 was confirmed in several large GWAS studies as one of the rare highly replicated schizophrenia susceptibility genes, and when haplo-insufficient TCF4 is the causative factor for Pitt-Hopkins Syndrome (PTHS). PTHS has compelling attributes in terms of human cognitive function, being associated with pronounced memory deficits, autistic behaviors, and importantly an almost complete lack of language development. Thus, understanding the roles and function of TCF4 in the CNS is highly significant with respect to human language and auditory cognition, memory function, autism spectrum behavior, and schizophrenia susceptibility. Despite the clear importance of TCF4 function in the human CNS, the basic neurobiology of TCF4 has been only sparsely studied. Thus, this Project will use genetically engineered mouse models to assess the role of TCF4 in memory, social interactions and communication, hippocampal synaptic plasticity, synaptic anatomy, and epigenomic and transcriptional regulation in the CNS. The central hypothesis of the proposed studies is that TCF4 regulates the brain's ability to trigger long-term synaptic plasticity and memory formation by actively regulating transcriptional activity in response to behavioral experience. The approach will be to use both germline constitutive knockout and acute knockdown or deletion of TCF4 in the adult mouse hippocampus, coupled with extensive behavioral, electrophysiological, and transcriptomic/epigenomic characterization, to determine if TCF4 function is necessary in an ongoing fashion for normal memory and synaptic plasticity in the mature CNS. The studies will capitalize not only upon the available germline knockout line but also upon an already-available floxed TCF4 allele mouse line, and combine these mice with both virus- driven cre expression in the adult hippocampus and post-developmental CaMKII promoter-driven forebrain neuron-selective cre expression to achieve inducible post-developmental attenuation of CNS TCF4 function in vivo. Using these novel mouse models we will undertake three Specific Aims. Aim 1 will test the hypothesis that TCF4-deficient mice exhibit cognitive memory and social interaction deficits, and also test the hypothesis that TCF4-deficient mice exhibit altered synaptic plasticity. Aim 2 will comprise a significant translational component of the studies and will test the hypothesis that transcription-promoting Histone DeAcetylase Inhibitors (HDACi) will restore learning, memory, and synaptic plasticity in TCF4-deficient mice, as proof-of- concept that behavioral deficits and plasticity deficits in PTHS model mice can be reversed pharmacologically with HDACi. Aim 3 will test the hypothesis that loss of TCF4 function triggers secondary alterations in chromatin structure, DNA methylation, and gene transcription in the mature CNS. Toward this end, we will use the unbiased approach of utilizing MBD-seq, mRNA-seq, and small RNA-seq approaches for a comprehensive analysis of potential transcriptomic and epigenomic alterations in TCF4-deficient mice.