Molecular dissection of synaptic dysfunction in mental disorders

自闭症谱系障碍(ASDS)和精神分裂症等多基因脑病的遗传学分析 (SZ)的研究表明，“突触功能障碍”是这些疾病的关键细胞底物。然而，将这一点转化为 突触假说对体外疾病建模和提取与疾病相关的生物信息具有 一直很有挑战性。PI之前已经建立了SZ的人类神经元模型，结合了相同的基因 基因组工程、患者来源的诱导多能干细胞(IPSCs)和诱导神经元 分化(在细胞内)。突触细胞黏附分子Neuresin-1基因突变的人类神经元 (NRXN1，2p16.3)，SZ的真正危险等位基因，表现出兴奋性突触强度和 神经递质释放概率以及钙/钙调蛋白依赖的持续上调 丝氨酸蛋白激酶(COASK)蛋白水平，其机制目前尚不清楚。它仍然存在 尚不清楚这些表型是如何产生并导致突触病理和异常神经元网络的 与疾病有牵连。在这项资助中，我们的目标是了解特定类型和发育的细胞 NRXN1-CASK相互作用在正常突触发育中的作用及其机制 SZ.使用突触分子作为代理，我们将剖析突触通路的中断如何启动或 积极参与深圳特区建设。我们将通过研究NRXN1突变体中异常的CASK信号来实现这一点 背景(目标1)，利用CASK KO诱导的人突触的正常功能研究CASK 神经元(目标2)和揭示NRXN1和CAASK在人前脑中介导的关键细胞事件 使用KO皮质球体模型进行开发(目标3)。我们的工作整合了成像技术， 电生理、生物化学和单细胞rna-seq，使用等基因进行严格的实验设计 来自多种遗传和性别背景的工程和患者来源的IPSCs，纯净的分化 具有明确突触特征的诱导神经元亚型和三维皮质球体的分化 具有典型的细胞特征。这笔赠款的调查结果将提供对 神经精神障碍的分子和细胞基础，这些信息将转化为其他 突触障碍，包括智力障碍、自闭症、躁郁症和情绪障碍。

Genetic analyses of polygenic brain disorders, such as autism spectrum disorders (ASDs) and schizophrenia (SZ), have revealed “synaptic dysfunction” as a key cellular substrate for these disorders. Yet, translating this synaptic hypothesis to in vitro disease modeling and extracting disease-relevant biological information has been challenging. The PI has previously established a human neuronal model of SZ, combining isogenic genome engineering, patient-derived induced pluripotent stem cells (iPSCs), and induced neuronal differentiation (iN cells). Human neurons bearing mutations in the synaptic cell adhesion molecule Neurexin-1 (NRXN1, 2p16.3), a bona fide risk allele for SZ, display deficits in excitatory synaptic strength and neurotransmitter release probability as well as a consistent upregulation of calcium/calmodulin-dependent serine protein kinase (CASK) protein level, by which the mechanism is currently not understood. It remains unclear how these phenotypes arise and lead to synaptic pathology and abnormal neuronal networks implicated in the disease. In this grant, we aim to understand the cell type- and developmental-specific functions of NRXN1-CASK interaction in normal synapse development and their mechanistic contributions to SZ. Using synaptic molecules as a proxy, we will dissect how disruptions in the synaptic pathway can prime or actively participate in SZ. We will achieve this by studying aberrant CASK signaling in NRXN1 mutant background (Aim 1), investigating CASK’s normal function at human synapses using CASK KO induced neurons (Aim 2) and by revealing key cellular events mediated by NRXN1 and CASK during human forebrain development using KO cortical spheroid models (Aim 3). Our work integrates techniques in imaging, electrophysiology, biochemistry and single cell RNA-seq with rigorous experimental designs using isogenic engineered and patient-derived iPSCs from multiple genetic and gender backgrounds, differentiation of pure induced neuronal subtypes with defined synaptic characteristics and differentiation of 3-D cortical spheroids with characterized cellular features. Findings of this grant will provide mechanistic understanding of the molecular and cellular underpinnings of neuropsychiatric disorders and such information will translate to other disorders of the synapse, including intellectual disability, ASDs, and bipolar and mood disorders.