Precision models of ARX-associated neurodevelopmental disorders

项目总结/摘要 近1%的美国人口患有癫痫（患病率5-8.4/1000）， 儿童的患病率。尽管这种高频率，分子和细胞的基础上，只有少数类型 癫痫的病因已经被定义，而大多数病因的基础仍然未知。一个基因的突变，ARX， 由于不同的突变与一系列神经系统疾病相关， 癫痫是少数几个一致的特征之一。ARX具有4个聚丙氨酸（pAla） 第一或第二束的扩张和扩张与癫痫一致相关。pAla束 扩展突变是一种相对较新描述的突变类型， 许多人类发育障碍，癫痫是几个组成部分。这种变异 类型的结果在人类疾病和癫痫，特别是没有得到很好的理解。我们之前的工作 证明了ARX的第一pAla区的扩增导致蛋白质的结构变化 所产生的蛋白质对发育中的皮质中间神经元和投射有不同的作用， 神经元祖细胞在其他研究中，我们已经表明，每个祖细胞的Arx缺失 群体占小鼠和人类表型的特定组分。在这个多PI R 01 根据我们过去十年的数据，我们寻求将人类干细胞模型与 小鼠模型来阐明ARX相关癫痫的病理生物学，特别是 pAla束沿着的功能与这些束中的突变。目标1将评估 患者源性球状体中的ARX pAla突变。目的2将研究ARXpAla突变的作用 对皮层中间神经元迁移和网络活动的影响。目的3将确定Arx pAla的作用 对大脑发育和功能的影响。该项目将利用人类诱导 多能干细胞（hiPSC）和球状体模型，并用小鼠胚胎干细胞补充这些模型 细胞系以及小鼠的行为和生理测定。这些研究预计将 提供了一个更好的了解如何pAla束功能在正常和异常的大脑发育， 有助于我们了解癫痫的发病机制，并产生宝贵的资源， 小鼠模型来测试发育性癫痫的潜在治疗策略。

PROJECT SUMMARY/ABSTRACT Nearly 1% of the US population suffers from epilepsy (prevalence 5-8.4/1000), with a slightly higher prevalence in children. Despite this high frequency, the molecular and cellular basis for only a few types of epilepsy have been defined, while the basis for most remains unknown. Mutations in one gene, ARX, are of considerable interest as distinct mutations are associated with a spectrum of neurological disorders with epilepsy representing one of the few consistent features. ARX has 4 poly-alanine (pAla) tracts and expansions in the 1st or 2nd tract are consistently associated with epilepsy. pAla tract expansion mutations are a relatively newly described mutation type and are associated with a growing number of human developmental disorders, epilepsy being a component of several. How this mutation type results in human disorders and epilepsy in particular are not well understood. Our prior work has demonstrated that an expansion in the first pAla tract of ARX results in structural change in the protein and the resulting protein has differential effects on developing cortical interneuron- and projection neuron progenitor cells. In other studies, we have shown that the loss of Arx from each progenitor population accounts for specific components of the mouse and human phenotypes. In this multi-PI R01 proposal, building on our data from the past ten years, we seek to unite human stem cell models with mouse models to elucidate the pathobiology underlying ARX related epilepsy, and specifically the function of pAla tracts along with mutations in these tracts. Aim 1 will evaluate the cellular impact of ARX pAla mutations in patient-derived spheroids. Aim 2 will examine the role of ARX pAla mutations on cortical interneuron migration and network activity. Aim 3 will determine the effects of Arx pAla expansion mutations on brain development and function. This project will utilize human induced pluripotent stem cell (hiPSC) and spheroid models and complement these with mouse embryonic stem cell lines and behavioral and physiological assays in mice. Together, these studies are expected to provide a greater understanding of how pAla tracts function in normal and abnormal brain development, contribute to our understanding of the pathogenesis of epilepsy, and generate valuable resources and mouse models to test potential therapeutic strategies for developmental epilepsies.