Development and Regulation of Cholinergic Synapses

描述（由申请人提供）：我们的长期科学目标是获得对突触传递的机械理解，重点是乙酰胆碱受体的建立和调节。肌肉和大脑中的快速胆碱能神经传递是通过突触释放的乙酰胆碱（ACh），其结合并激活离子通道形成五聚体受体（AChR）。这些受体在进化上是保守的，并且无脊椎动物和脊椎动物生物体表达大家族的AChR亚基，其可以形成异聚体或同聚体AChR。各种受体对药物（如成瘾药物尼古丁）表现出不同的敏感性，受体的多样性有助于神经元功能和药物依赖性。特别是一种受体，同聚体α 7 AChR，与自闭症，焦虑症和精神分裂症有关。α 7介导的神经传递的强度关键取决于α 7 AChR的定位和密度;然而，这些受体或任何AChR如何被递送到突触并定位在突触处仍然没有很好地理解。该提案的目标是通过在秀丽隐杆线虫中使用遗传方法来识别有助于α 7样AChRs的递送或功能的信号通路，来获得AChR介导的突触信号传导的机制理解。我们以前证明了由ACR-16介导的突触电流。elegans α 7同源物依赖于CAM-1，一种Ror类受体酪氨酸激酶（RTK）。我们现在有初步的数据表明，在三个基因编码的蛋白质，有助于Wnt介导的信号（CWN-2/Wnt，LIN-17/Fzd，和DSH-1/Dvl）的突变表型复制的行为和电生理缺陷中发现的cam-1突变体。在该提案中，我们测试了所有四种蛋白质都有助于Wnt介导的信号通路的模型，该信号通路是突触ACR-16受体的递送、定位或功能所需的，我们阐明了下游信号组分，并且我们测量了受体运输的体内动力学。胆碱能神经传递与尼古丁成瘾、记忆和认知有关。α 7 AChR调节和功能的扰动被认为有助于广泛的神经元疾病，如自闭症、焦虑症和精神分裂症，以及阿尔茨海默病和帕金森病。由于许多对突触传递重要的基因产物在无脊椎动物到脊椎动物中是保守的，我们预测我们从C。秀丽隐杆线虫将与正在进行的脊椎动物神经系统研究直接相关。因此，我们的研究工作可能最终导致新的诊断或治疗方式与胆碱能神经传递缺陷相关的神经元疾病。 公共卫生相关性：兴奋性神经传递是由神经递质乙酰胆碱介导的，乙酰胆碱与专门的受体结合，控制肌肉的收缩、腺体的分泌和大脑的运作;尼古丁可以部分模拟乙酰胆碱的作用，是香烟烟雾中发现的导致成瘾的活性成分。乙酰胆碱介导的信号传导功能障碍与尼古丁成瘾、记忆和认知以及广泛的神经元疾病如自闭症、焦虑症、精神分裂症、阿尔茨海默病和帕金森病有关。本申请的目标是获得对乙酰胆碱受体的发育和调节的更深入的机械理解，这最终可能有助于开发神经系统疾病的新诊断和治疗方式。

DESCRIPTION (provided by applicant): Our long-term scientific goal is to gain a mechanistic understanding of synaptic transmission, with a focus on the establishment and regulation of acetylcholine receptors. Rapid cholinergic neurotransmission at muscles and in the brain is via synaptically released acetylcholine (ACh), which binds to and activates ion-channel forming pentameric receptors (AChRs). These receptors are evolutionarily conserved, and invertebrate and vertebrate organisms express large families of AChR subunits, which can form heteromeric or homomeric AChRs. The various receptors exhibit differential sensitivity to drugs (such as the addictive drug nicotine), and the diversity of receptors contributes to neuronal function and drug dependence. One receptor in particular, the homomeric a7 AChR, is associated with autism, anxiety and schizophrenia. The strength of a7-mediated neurotransmission is critically dependent on the localization and density of a7 AChRs; however, how these receptors or any AChRs are delivered to and localized at synapses is still not well understood. The goal of this proposal is to gain a mechanistic understanding of AChR-mediated synaptic signaling by using a genetic approach in Caenorhabditis elegans to identify signaling pathways that contribute to the delivery or function of a7-like AChRs. We previously demonstrated that synaptic currents mediated by ACR-16, a C. elegans a7 homologue, are dependent on CAM-1, a Ror class receptor tyrosine kinase (RTK). We now have preliminary data demonstrating that mutations in three genes encoding proteins that contribute to Wnt-mediated signaling (CWN-2/Wnt, LIN-17/Fzd, and DSH-1/Dvl) phenocopy the behavioral and electrophysiological defects found in cam-1 mutants. In this proposal we test the model that all four proteins contribute to a Wnt-mediated signaling pathway that is required for the delivery, localization or function of synaptic ACR-16 receptors, we elucidate downstream signaling components, and we measure the in vivo dynamics of receptor trafficking. Cholinergic neurotransmission is implicated in nicotine addiction, memory and cognition. Perturbations in a7 AChR regulation and function are thought to contribute to a broad spectrum of neuronal disorders such as autism, anxiety, and schizophrenia, as well as Alzheimer's and Parkinson's diseases. Because many of the gene products important for synaptic transmission are conserved from invertebrates to vertebrates, we predict that what we learn from our studies in C. elegans will have immediate relevance to ongoing studies in the vertebrate nervous system. Thus, our research efforts might ultimately lead to new diagnostic or therapeutic modalities for neuronal disorders associated with defects in cholinergic neurotransmission. PUBLIC HEALTH RELEVANCE: Excitatory neurotransmission is mediated by the neurotransmitter acetylcholine, which binds to specialized receptors and controls the contraction of muscles, the secretion of glands and the workings of the brain; nicotine can partly mimic the action of acetylcholine and is the active ingredient found in cigarette smoke that leads to addiction. Dysfunction of acetylcholine-mediated signaling is implicated in nicotine addiction, memory and cognition, and a broad spectrum of neuronal disorders such as autism, anxiety, schizophrenia, and Alzheimer's and Parkinson's diseases. The goal of this application is to gain a greater mechanistic understanding of the development and regulation of acetylcholine receptors, which ultimately may contribute to the development of new diagnostic and therapeutic modalities for neurological disorders.