Mouse model studies of TMEM230-linked Parkinson's disease

通过我们以前由美国帕金森病协会和NINDS资助的工作，我们已经 在20号染色体的短臂上发现了一个新的帕金森病（PD）遗传位点，并确定了一个 新的PD基因TMEM 230。TMEM 230编码分泌和再循环囊泡的跨膜蛋白， 包括神经元中的突触囊泡。TMEM 230是突触囊泡的第一个跨膜蛋白 至今在PD中发现。因此，我们的研究结果直接指向突触囊泡的功能障碍， PD的发病机制。TMEM 230的确切生理功能和致病机制 TMEM 230介导的PD仍不清楚。根据TMEM 230的分子特征， 在我们的研究中测试了突触囊泡和内体标记物，我们假设TMEM 230是一个 突触囊泡的运输蛋白，并且它可能在突触囊泡生物发生，胞吐， 内吞和再循环以及神经元中的突触传递。但仍有待确定的是， 亚细胞区室和TMEM 230的功能。在上一个融资周期中，我们确定了 TMEM 230作为结合衔接蛋白2的中亚基（AP 2 M1）的内吞货物蛋白 复合物（AP 2）促进AP 2依赖性网格蛋白介导的内吞作用;而PD连锁突变影响 这一过程并损害突触囊泡的再循环，更具体地说，是通过影响突触前 膜形成新的AP 2/网格蛋白包被的回收囊泡。在本申请中，我们提出了三个具体的 旨在确定TMEM 230的生理功能，特别是TMEM 230的功能基序， 与AP 2 M1结合，以及TMEM 230相关PD的致病机制。我们建议发展一个 在具体目标1中，共建立了6个TMEM 230小鼠模型，以进行表型、病理和生化分析 在特定目标2中进行黑质纹状体通路的神经生理学表征， 这些小鼠模型的具体目标3. SV再循环缺陷已成为PD发病机制的一个会聚致病途径。那里 是LRRK 2、生长素和synaptojanin 1影响网格蛋白脱壳的证据; VPS 35可能损害retromer， TGN贩毒。TMEM 230似乎影响SV再循环中的一个独特步骤，即，从突触前 膜形成新的AP 2/网格蛋白涂层回收SV。一些重要问题仍有待解决。 处理。基于我们的资源和专业知识，我们建议使用相关的 在这个应用程序中的鼠标模型。成功完成拟议的研究将提供必要的 了解TMEM 230的生理功能和致病机制的信息 TMEM 230相关PD。此外，由于TMEM 230相关的PD显示出临床和病理特征， 与经典PD的结果一致，本研究的结果也可能对以下方面具有重要意义： 了解其他形式的PD的致病机制，包括散发性PD。

Through our previous work funded by the American Parkinson Disease Association and NINDS, we have discovered a new Parkinson’s disease (PD) genetic locus on the short arm of chromosome 20, and identified a new PD gene, TMEM230. TMEM230 encodes a transmembrane protein of secretory and recycling vesicles, including synaptic vesicles in neurons. TMEM230 is the first transmembrane protein of synaptic vesicles identified in PD to date. Our findings, therefore, directly point to the dysfunction of synaptic vesicles in the pathogenesis of PD. The precise physiological functions of TMEM230, and pathogenic mechanism of the TMEM230-mediated PD remain unclear. Based on the molecular features of TMEM230, and its relationship with synaptic vesicle and endosomal markers tested in our study, we hypothesize that TMEM230 is a trafficking protein of synaptic vesicles, and it may function in synaptic vesicle biogenesis, exocytosis, endocytosis and recycling, and synaptic transmission in neurons. But it remains to be determine where in the subcellular compartments and what functions that TMEM230 plays. In the previous funding cycle, we identified TMEM230 as an endocytic cargo protein that binds to the medium subunit (AP2M1) of adaptor protein 2 complex (AP2) to promote AP2-dependent clathrin-mediated endocytosis; whereas, PD-linked mutations affect this process and impair synaptic vesicle recycling, more specifically, by affecting budding from presynaptic membrane to form new AP2/clathrin-coated recycling vesicles. In this application, we propose three specific aims to determine the physiological function of TMEM230, especially the functional motifs for TMEM230 to bind to AP2M1, and the pathogenic mechanism underlying TMEM230-linked PD. We propose to develop a total of six TMEM230 mouse models in specific aim 1, to perform phenotypical, pathological and biochemical characterization in specific aim 2, and to perform neurophysiological characterization of nigrostriatal pathway in these mouse models in specific aim 3. SV recycling deficits have emerged as a convergent pathogenic pathway underlying PD pathogenesis. There is evidence that LRRK2, auxilin and synaptojanin 1 affect clathrin uncoating; and VPS35 may impair retromer- TGN trafficking. TMEM230 appears to affect a distinct step in SV recycling i.e., budding from the presynaptic membrane to form new AP2/clathrin-coated recycling SVs. A number of important issues remains to be addressed. Based on our resources and expertise, we propose to address some of these issues using relevant mouse models in this application. Successful completion of the proposed studies will provide essential information to understand the physiological function of TMEM230 and the pathogenic mechanism underlying TMEM230-linked PD. Moreover, since TMEM230-linked PD shows clinical and pathological features compatible with those in classical PD, the outcomes from this study may also have important implications in understanding the pathogenic mechanisms in other forms of PD, including sporadic PD.