Cellular and molecular mechanisms disrupted in 22q13 deletion syndrome and autism

编码突触蛋白的基因突变和功能性大脑连接受损正在出现 与自闭症谱系障碍（ASD）相关的常见缺陷。然而，突变的突触 蛋白质在细胞和分子水平上影响人类神经元的特性， 连接仍然是一个重要的未回答的问题。解决这一问题对于以下方面至关重要： 了解ASD的病因和病理，并开发新的有效的治疗策略 对患者PI先前证明SHANK 3缺陷的人皮层神经元来源于 从患有自闭症的22 q13缺失综合征患者中产生的诱导多能干细胞（iPSC）， 严重损害内在兴奋性和兴奋性突触传递。然而，这两个 表型的发展和影响大脑中神经元的连接仍然是未知的。这个的主要目标 该项目旨在阐明负责突触发育的细胞和分子机制， SHANK 3缺陷的人类神经元的连接缺陷。SHANK 3是一种支架蛋白，表达于 在自闭症患者中经常发现突变或缺失的兴奋性突触， 智力残疾。该项目的中心假设是SHANK 3缺陷的人中的突触缺陷， 神经元的发育是电活动增加和活动介导的减弱和消除的结果。 兴奋性突触PI中获得的初步数据强烈支持这一假设 实验室以下具体目的是制定测试这一假设：1）确定的作用，提高 在SHANK 3缺陷的人类神经元中突触缺陷发展中的电活动; 2）确定 ARC在SHANK 3缺陷的人神经元中突触缺陷的发展中的作用;以及3）确定如何 人类神经元中SHANK 3的缺失会影响体内这些神经元的突触输入。根据这些目标， 由新的、精确的基因工程干细胞系产生的人类皮层神经元的特性将 在体外和植入后使用电生理学、成像和生物化学技术进行研究 注入老鼠的大脑这项拟议中的研究意义重大，因为预计它将大大推进 理解自闭症和智力障碍中被破坏的分子、细胞和电路机制， 残疾，并指导开发新的治疗策略的患者。

Mutations in genes encoding synaptic proteins and impaired functional brain connectivity are emerging as common deficits associated with autism spectrum disorders (ASDs). However, how mutated synaptic proteins affect the properties of human neurons at the cellular and molecular levels to cause abnormal brain connections remains an important unanswered question. Addressing this question is essential for understanding the etiology and pathology of ASDs and developing novel and effective therapeutic strategies for patients. The PI previously demonstrated that SHANK3-deficient human cortical neurons derived from induced pluripotent stem cells (iPSCs), generated from 22q13 deletion syndrome patients with autism, have severely impaired intrinsic excitability and excitatory synaptic transmission. However, how these two phenotypes develop and affect neuronal connectivity in the brain remain unknown. The main goal of this project is to elucidate the cellular and molecular mechanisms responsible for development of synaptic and connectivity deficits in SHANK3-deficient human neurons. SHANK3 is a scaffolding protein expressed at excitatory synapses that have been frequently found to be mutated or deleted in individuals with autism and intellectual disability. The central hypothesis of this project is that synaptic deficits in SHANK3-deficient human neurons develop as a result of elevated electrical activity and activity-mediated weakening and elimination of excitatory synapses. This hypothesis is strongly supported by the preliminary data obtained in the PI's laboratory. The following Specific Aims are formulated to test this hypothesis: 1) Determine the role of elevated electrical activity in development of synaptic deficits in SHANK3-deficient human neurons; 2) Determine the role of ARC in development of synaptic deficits in SHANK3-deficient human neurons; and 3) Determine how loss of SHANK3 in human neurons impacts synaptic inputs onto these neurons in vivo. Under these aims, the properties of human cortical neurons generated from novel, precisely genetically-engineered stem cell lines will be investigated using electrophysiology, imaging, and biochemistry techniques in vitro and upon engraftment into the mouse brain. The proposed research is significant because it is expected to substantially advance understanding of the molecular, cellular, and circuitry mechanisms disrupted in autism and intellectual disability, and guide the development of novel therapeutic strategies for patients.