Control of Excitatory Synapse Formation by Huntingtin

亨廷顿蛋白对兴奋性突触形成的控制

• 批准号: 9398905
• 负责人: Katherine Therese Baldwin
• 金额: $ 5.9万
• 依托单位: DUKE UNIVERSITY
• 依托单位国家: 美国
• 财政年份: 2017
• 资助国家: 美国
• 起止时间: 2017-05-01 至 2020-04-30
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/9398905
• 关键词: Affect; Aging; Appearance; Astrocytes; Behavioral Assay; Behavioral Symptoms; Biochemical; Biochemistry; Brain; Brain Diseases; C-terminal; CD36 Antigens; Cell Death; Cells; Confocal Microscopy; Corpus striatum structure; Defect; Development; Disease; Disease Progression; Disease model; Dorsal; Equilibrium; Excitatory Synapse; Functional Imaging; Functional disorder; Genetic; Genetic study; Growth; Huntington Disease; Huntington gene; Huntington protein; Impairment; In Vitro; Inherited; Intervention; Knowledge; Laboratories; Life; Membrane; Molecular; Molecular Biology; Motor Cortex; Mus; Mutate; Mutation; Names; Nature; Nerve Degeneration; Neurobehavioral Manifestations; Neurodegenerative Disorders; Neurons; Onset of illness; Pathogenesis; Patients; Pharmacology; Phenotype; Protein Family; Proteins; Research; Role; Signal Transduction; Symptoms; Synapses; Tail; Testing; Therapeutic; Thrombospondins; Universities; Work; base; disease-causing mutation; experimental study; gabapentin; gain of function; genetic approach; genetic manipulation; imaging study; inhibitor/antagonist; motor disorder; mouse model; mutant; novel therapeutics; polyglutamine; postnatal; prevent; receptor; stem; synaptogenesis

Title: Control of Excitatory Synapse Formation by Huntingtin Abstract: Huntington’s Disease (HD) is an inherited, fatal neurodegenerative disease caused by an expansion of poly-glutamine (poly-Q) repeats in the N-terminus of the Huntingtin (Htt) protein. While the causative mutation for HD can be detected long before disease onset, there are currently no treatments to prevent or delay neurodegeneration in HD. The dominant nature of the Htt mutation led to the hypothesis that HD is caused by a toxic gain-of-function of the mutant Htt protein. Therefore, the majority of HD therapeutic strategies are focused on reducing or eliminating mutant Htt. Recent work from our laboratory and others suggests an alternative hypothesis, that loss of Htt function is also a major driver of disease pathogenesis. In mouse genetic studies, our lab found that cortical Htt is required for the correct establishment of cortical and cortico- striatal excitatory synaptic connections, and that this function of Htt is lost when mutant Htt is present. What are the functions of wild-type Htt in establishing and maintaining synaptic connections? How does disruption of wild-type Htt function contribute to HD pathogenesis? These are the questions that I will answer during my postdoctoral research in Dr. Cagla Eroglu’s laboratory at Duke University. In my preliminary experiments I found an unexpected role for neuronal Htt as a regulator of astrocyte- induced synaptogenesis. Astrocytes secrete thrombospondin (TSP) family proteins, which induce synapse formation via their neuronal receptor, the gabapentin receptor α2δ-1. In biochemical experiments, I found that α2δ-1 directly interacts with wildtype Htt, but this interaction is impaired when the disease-causing poly-Q repeat expansion is present in Htt. Furthermore, Htt is required in neurons to suppress synaptogenesis in the absence of TSP signaling, suggesting that Htt and α2δ-1 have opposing functions that balance the growth of excitatory synaptic connectivity. Based on these findings, I developed the hypothesis that Htt is an inhibitor of excitatory synapse formation. I will use a combination of primary neuronal culture, molecular biology, biochemistry, confocal microscopy, and mouse genetics, to test the hypothesis that Htt controls synaptic connectivity through its interaction with α2δ-1, and that this function of Htt is impaired when the poly-Q expansion is present. Additionally, I will determine whether the genetic manipulation of α2δ-1 expression can rescue synaptic deficits and delay or stop disease progression in HD model mice. Collectively, I expect these studies will significantly advance the field of HD research by identifying specific molecular mechanisms through which loss of wild-type Htt function contributes to disease pathogenesis. Furthermore, these findings are poised to provide novel therapeutic strategies to treat early synaptic dysfunction and delay or prevent onset of neurodegeneration in HD.

标题：通过亨廷顿控制兴奋性突触形成 抽象的： 亨廷顿氏病（HD）是一种遗传性的致命神经退行性疾病，原因是 在亨廷顿蛋白（HTT）蛋白的N末端重复多谷氨酰胺（Poly-Q）。而因果突变 因为可以在疾病发作之前很长时间检测到高清，目前尚无预防或延迟的治疗方法 HD中的神经变性。 HTT突变的主要性质导致假设HD是由 突变体HTT蛋白的有毒功能。因此，大多数高清治疗策略是 专注于减少或消除突变体HTT。我们实验室和其他人的最新工作表明 替代假设，HTT功能的丧失也是疾病发病机理的主要驱动力。在鼠标中 遗传研究，我们的实验室发现，正确建立皮质和皮质的皮质HTT是必需的 纹状体兴奋性突触连接，并且在存在突变的HTT时丢失了HTT的此功能。什么 野生型HTT的功能是否在建立和维持突触连接中？怎么样 野生型HTT功能的破坏有助于HD发病机理？这些是我会的问题 在我在杜克大学Cagla Eroglu博士实验室的博后研究期间的回答。 在我的初步实验中，我发现神经元HTT作为星形胶质细胞调节剂的意外作用 诱导的突触发生。星形胶质细胞秘密血小板可能（TSP）家族蛋白，诱导突触 通过其神经元受体Gabapentin受体α2δ-1形成。在生化实验中，我发现 α2δ-1直接与WildType HTT相互作用，但是当引起疾病的Poly-Q时，这种相互作用会受到损害 HTT中存在重复扩展。此外，神经元中需要HTT抑制突触发生 没有TSP信号传导，表明HTT和α2δ-1具有相反的功能，可以平衡 兴奋性合成连通性。基于这些发现，我提出了以下假设：HTT是 兴奋性突触形成。我将结合原发性神经元培养，分子生物学， 生物化学，共聚焦显微镜和小鼠遗传学，以检验HTT控制突触的假设 连通性通过与α2δ-1的相互作用而进行的连通性，当poly-q时，HTT的这种功能受到损害 存在扩展。此外，我将确定α2δ-1表达的基因操纵是否可以 救援合成定义和延迟或停止HD模型小鼠的疾病进展。总的来说，我希望这些 研究将通过通过确定特定的分子机制来显着推动HD研究领域 野生型HTT功能的丧失有助于疾病发病机理。此外，这些发现是 中毒以提供新的治疗策略来治疗早期突触功能障碍并延迟或防止发作 HD中的神经变性。