Synaptic signaling in a human stem cell model of Angelman syndrome

描述（由申请人提供）：染色体15 q11-q13缺失的个体患有安格尔曼综合征（AS），这是一种神经遗传性发育障碍，其特征为智力残疾、运动性共济失调、言语缺失和癫痫发作。特定的基因 负责AS的编码泛素蛋白连接酶UBE 3A。在AS中，突触信号传导和可塑性的缺陷似乎在疾病表型中起关键作用，但UBE 3A及其相关下游靶点的确切功能作用尚不清楚。为了开发适当的治疗AS，有必要了解UBE 3A缺失引起的病理生理变化。直到最近，还不可能检查受影响个体的脑神经元的功能特性。 将人类体细胞基因组重编程为诱导多能干细胞（iPSC）系的发现为模拟具有复杂遗传学的人类疾病提供了一种新的方法。我们最近成功地将AS患者以及年龄匹配的对照受试者的真皮成纤维细胞重编程为iPSC，然后将这些细胞分化为功能性神经元 维持AS患者中UBE 3A表达的印记表型。我们现在准备利用这些新的患者来源的细胞系来测试有关AS潜在生理缺陷的特定假设。第一个目的是使用电生理和免疫细胞化学方法来探索iPSC衍生的神经元的内在功能特性和突触连接的活性依赖性可塑性。 救援实验将集中在即时早期基因ARC和钙/钙调素依赖性蛋白激酶CaMKII在AS相关的突触信号转导缺陷中的作用。 第二个目标将探讨AS衍生神经元中突触数量和树突棘密度的变化。救援实验将针对ephexin-5的作用，ephexin-5是UBE 3A的底物，在发育过程中调节兴奋性突触数量。总的来说，这种方法可能被证明是有用的，以确定新的药物发现的目标和筛选潜在的治疗，旨在改善和/或治愈癫痫发作，运动障碍，语言和认知障碍的Angelman综合征。 公共卫生相关性：Angelman综合征是一种以智力障碍、运动性共济失调、言语缺失和癫痫发作为特征的神经遗传性发育障碍。这项研究使用了一种新的人类干细胞培养模型来研究这些缺陷的细胞和分子基础。长期目标是确定新的治疗靶点 用于治疗安格尔曼综合征和其他自闭症相关疾病。

DESCRIPTION (provided by applicant): Individuals with a deletion of chromosome 15q11-q13 suffer from Angelman syndrome (AS), a neurogenetic developmental disorder characterized by intellectual disability, motor ataxia, absent speech, and seizures. The specific gene that is responsible for AS encodes the ubiquitin protein ligase UBE3A. In AS, deficits in synaptic signaling and plasticity appear to play a critical role in the disease phenotype, but the exact functional role of UBE3A and its relevant downstream targets are unknown. In order to develop appropriate treatments for AS, it is necessary to understand the pathophysiological changes caused by UBE3A deletion. Until recently it has not been possible to examine the functional properties of brain neurons in affected individuals. The discovery of genomic reprogramming of human somatic cells into induced pluripotent stem cell (iPSC) lines provides a novel way to model human diseases with complex genetics. We have recently succeeded in reprogramming dermal fibroblasts from AS patients, as well as age-matched control subjects, into iPSCs, and then differentiated these cells into functional neurons that maintain the imprinting phenotype of UBE3A expression seen in AS patients. We are now poised to take advantage of these novel patient-derived cell lines to test specific hypotheses about the underlying physiological defects in AS. The first aim uses electrophysiological and immunocytochemical approaches to explore the intrinsic functional properties of iPSC-derived neurons and activity-dependent plasticity of synaptic connections. Rescue experiments will focus on the roles of the immediate early gene ARC and the calcium/calmodulin-dependent protein kinase CaMKII in AS-associated deficits in synaptic signaling. The second aim will explore changes in synapse number and dendritic spine density in AS-derived neurons. Rescue experiments will target the role of ephexin-5, a substrate of UBE3A that plays a role in regulating excitatory synapse number during development. Overall, this approach may prove useful for identifying novel targets for drug discovery and for screening potential therapeutics aimed at ameliorating and/or curing the seizures, movement disorders, and language and cognitive impairments in Angelman syndrome. PUBLIC HEALTH RELEVANCE: Angelman syndrome is a neurogenetic developmental disorder characterized by intellectual disability, motor ataxia, absent speech, and seizures. The proposed research uses a novel human stem cell culture model to investigate the cellular and molecular basis of these deficits. The long term objective is to identify novel therapeutic targets for treating Angelman syndrome and other autism-related disorders.