Functional roles of genetic risk factors for brain disorders in neurogenesis and neurodevelopment

该计划的首要目标是定义神经发育过程中易受遗传扰动影响的细胞和分子事件，这些扰动增加了神经发育和神经疾病的风险。目前，我们对人脑发育的了解主要是从动物模型、人类发育的间接测量以及对人类神经组织的有限接触中推断出来的。所有这些都是拼凑人类神经发育顺序过程的有效工具，但不足以用足够的时间或分子分辨率来描述动力学，以机械地理解遗传风险因素如何影响大脑的形成和功能。细胞重编程技术的进步使从成年患者中获得诱导多能干细胞(IPSCs)成为可能，IPSCs是一种可再生资源，用于产生具有疾病相关遗传特征的人类神经元。这一长期研究计划旨在将基于IPSC的人类研究与动物模型结合起来，以提供对神经发育的全面和纵向了解，从神经干细胞行为到神经元发育、突触形成和电路整合。作为原则的证明，这些研究将使用多种神经疾病的显著拷贝数变异(CNV)风险因素15q11.2CNvs，以说明在遗传变异的背景下对神经发育的基本生物学进行多方面询问如何揭示新的靶点，以测试基于机制的干预在相关人类神经元亚型以及神经功能和行为的动物模型中的作用。基于我们在干细胞生物学、成人神经发生和特定于患者的IPSCs领域取得的重大科学发现，以及我们为应对这些领域的关键挑战而开发的技术创新，我们的主要研究重点是整合多个层次的分析，以提供可用于探索神经疾病的遗传或环境风险的神经发育细胞过程和分子机制的高分辨率描述。将开展三个相互关联的项目。项目1将重点研究成年小鼠的神经发生作为神经发育的模型，并利用神经干细胞及其发育的克隆分析、单细胞转录组分析和转基因小鼠模型来剖析基因突变对神经发育的分子、细胞和电路水平的影响；项目2将使用具有已知遗传风险因素的人IPSCs和靶向分化方案，以询问2D和3D培养中的人类神经发育；项目3将侧重于在动物模型和人类IPSC来源的神经元中确定风险基因的分子机制和靶点，并通过合理的治疗干预来挽救观察到的缺陷。现在是综合最新开发的技术和建立一个新的翻译平台来研究神经疾病的潜在机制，并促进确定诊断、治疗和预防神经发育失调的通常令人衰弱的后果的策略的好时机。

The overarching goal of this program is to define cellular and molecular events during neural development vulnerable to genetic perturbations that increase risk for neurodevelopmental and neurological disorders. Currently, our knowledge of human brain development is largely inferred from animal models, indirect measures of human development, and limited access to human neural tissue. All of these are valid tools to piece together the sequential processes of human neural development but are not sufficient to describe the dynamics with enough temporal or molecular resolution to understand mechanistically how genetic risk factors can affect brain formation and function. Technological advances in cellular reprogramming have now made it possible to derive induced pluripotent stem cells (iPSCs) from adult patients, which are a renewable resource for the generation of human neurons with disease-relevant genetic features. This long-term research program is designed to incorporate human iPSC-based studies with animal models to provide a comprehensive and longitudinal understanding of neural development, from neural stem cell behavior to neuronal development, synapse formation and circuit integration. As a proof-of-principle, these studies will use a prominent copy number variation (CNV) risk factor for multiple neurological disorders, 15q11.2CNVs, to illustrate how multifaceted interrogations of the basic biology of neural development in the context of genetic variation can reveal new targets for testing mechanism-based intervention in relevant subtypes of human neurons, as well as animal models of neural function and behavior. Building on significant scientific discoveries we have made in the fields of stem cell biology, adult neurogenesis, and patient-specific iPSCs, and technological innovations we have developed to meet critical challenges in each of these fields, our primary research focus is to integrate multiple levels of analysis to provide a high-resolution description of the cellular processes and molecular mechanisms of neural development that can be used to probe genetic or environmental risk for neurological disorders. Three interlinked projects will be pursued. Project 1 will focus on adult mouse neurogenesis as a model for neural development and use clonal analysis of neural stem cells and their development, single-cell transcriptome analysis, and transgenic mouse models to dissect molecular, cellular, and circuit level effects of genetic mutations on neural development; Project 2 will use human iPSCs with known genetic risk factors, and targeted differentiation protocols, to interrogate human neural development in 2D and 3D cultures; and Project 3 will focus on identifying the molecular mechanisms and targets of risk genes in both animal models and human iPSC-derived neurons and the rescue of observed deficits through rational therapeutic intervention. This is an opportune moment to synthesize recently developed technologies and build a novel translational platform to study underlying mechanisms of neurological disorders, and facilitate the identification of strategies to diagnose, treat, and prevent the often debilitating consequences of dysregulated neural development.