Molecular Pathogenesis Of Hereditary Spastic Paraplegias

遗传性痉挛性截瘫的分子发病机制

• 批准号: 7594693
• 负责人: Craig D Blackstone
• 金额: $ 156.05万
• 依托单位: NATIONAL INSTITUTE OF NEUROLOGICAL DISORDERS AND STROKE
• 依托单位国家: 美国
• 资助国家: 美国
• 起止时间: 至
• 项目状态: 未结题
• 来源: https://reporter.nih.gov/project-details/7594693
• 关键词: Acids; Aldehyde dehydrogenase (NAD+); American; Amish; Amyotrophic Lateral Sclerosis; Animals; Behavioral; Cells; Cellular biology; Clinical; Complex; Development; Disease; Disease model; Disruption; Drosophila chb protein; Endocytosis; Endoplasmic Reticulum; Epidermal Growth Factor Receptor; Family; Functional disorder; Genes; Genetic; Goals; Golgi Apparatus; Growth Cones; Guanosine Triphosphate Phosphohydrolases; Hereditary Dystonia; Hereditary Spastic Paraplegia; Human; Inherited; Investigation; Knockout Mice; Laboratories; Lead; Length; Localized; Maps; Membrane Protein Traffic; Mitochondrial Diseases; Modeling; Molecular; Morphogenesis; Motor Neurons; Mus; Mutation; Nervous system structure; Neurodegenerative Disorders; Neurology; Neurons; Numbers; Pathogenesis; Pathway interactions; Patients; Personal Satisfaction; Precipitation; Primary Lateral Sclerosis; Protein Isoforms; Proteins; Range; Reporting; Research; Role; Screening procedure; Spastic Paraplegia; Syndrome; Systems Analysis; Techniques; Troyer syndrome; Tubular formation; Yeasts; aldehyde dehydrogenases; axon growth; axonopathy; clinically relevant; early onset; functional group; insight; loss of function; mouse model; nervous system disorder; novel; prevent; small hairpin RNA; structural biology; trafficking; yeast two hybrid system

Research in the Cellular Neurology Unit focuses on the molecular mechanisms underlying a number of neurodegenerative disorders, including mitochondrial disorders, dystonia, and the hereditary spastic paraplegias (HSPs). These disorders, which together afflict millions of Americans, worsen insidiously over a number of years, and treatment options are limited for many of them. Our laboratory is investigating inherited forms of these disorders, using molecular and cell biology approaches to study how mutations in disease genes ultimately result in cellular dysfunction. In this project, we are focusing on the HSPs. One major theme involves the characterization and functional analysis of the hereditary spastic paraplegia type 3A (SPG3A) protein, atlastin-1. We have reported that although this large GTPase is enriched in vesicular tubular complexes and cis-Golgi apparatus in cells, it is also highly enriched in axonal growth cones in neurons. We found that some SPG3A patient mutations result in decreased GTPase activity of the atlastin-1 protein, while others appear to decrease protein stability. Modeling these loss-of-function changes in cultured neurons using shRNA, we found that loss of atlastin-1 inhibits the growth of axons, presenting a compelling case for abnormal development in the pathogenesis of the very early onset hereditary spastic paraplegia type 3A. More recently, we have been studying several other human atlastin-like proteins (atlastin-2 and -3) that we identified. We have determined that, in contrast to atlastin-1, these two proteins localize to the endoplasmic reticulum. However, all atlastins appear to be important for ER and Golgi morphogenesis. We are currently identifying atlastin-interacting proteins by co-precipitation studies and yeast two-hybrid screening to clarify further their functional roles within cells. In another project, we have been studying the complicated HSP known as Troyer syndrome (SPG20), which is cause by a mutation in the spartin protein. Interestingly, we have found that the spartin protein, like its interaction partner Eps15, is involved in the internalization and degradation of the EGF receptor, prefiguring a critical role for spartin in endocytosis. We are currently investigating the function of spartin in the nervous system by analyzing spartin-null mice that we have generated as a murine model of Troyer syndrome. In addition, we very recently reported the clinical features of a new Old Order Amish family with Troyer syndrome and showed that the spartin protein is completely absent in cells derived from these patients. In a final project related to the HSPs, we have been investigating the complicated HSP known as MAST syndrome (SPG21), which is caused by a large deletion in the acid cluster protein maspardin. We have generated maspardin-null mice as a murine model for this disorder and are investigating these animals using behavioral techniques in addition to using neurons and other cells derived form these animals for cellular trafficking studies. Lastly, we have recently completed a study characterizing the interaction of the maspardin protein with a specific isoform of aldehyde dehydrogenase, ALDH16A1. Taken together, we expect that our studies will advance our understanding of the molecular pathogenesis of the HSPs. Such an understanding at the molecular and cellular levels will hopefully lead to novel treatments to prevent progression of these disorders.

细胞神经病学部门的研究重点是许多神经退行性疾病的分子机制，包括线粒体疾病，肌张力障碍和遗传性痉挛性跨性疾病（HSPS）。 这些疾病共同遭受了数百万美国人的困扰，在多年中，阴险的恶化，其中许多疾病受到限制。 我们的实验室正在使用分子和细胞生物学方法研究这些疾病的遗传形式，以研究疾病基因中的突变如何最终导致细胞功能障碍。 在这个项目中，我们专注于HSP。一个主要主题涉及遗传性痉挛性截瘫3A（SPG3A）蛋白Atlastin-1的表征和功能分析。 我们报告说，尽管这种大的GTPase富含细胞中的囊泡管状复合物和顺式高尔基体，但它在神经元的轴突生长锥中也高度富集。 我们发现某些SPG3A患者突变导致atlastin-1蛋白的GTPase活性降低，而另一些似乎降低了蛋白质的稳定性。 通过使用SHRNA对这些功能丧失的变化进行建模，我们发现atlastin-1的损失抑制了轴突的生长，这是一种令人信服的案例，用于在早期发作的遗传性遗传性痉挛性瘫痪3a中的发病机理中异常发育。 最近，我们一直在研究我们确定的其他几种人atlastin样蛋白（Atlastin-2和-3）。 我们已经确定，与atlastin-1相比，这两种蛋白质定位于内质网。 然而，所有伊植物似乎对ER和高尔基体形态发生都很重要。 我们目前正在通过共沉淀研究和酵母双​​杂交筛选来鉴定截骨蛋白相互作用的蛋白质，以进一步阐明它们在细胞中的功能作用。 在另一个项目中，我们一直在研究复杂的HSP，称为Troyer综合征（SPG20），这是由于Spartin蛋白的突变引起的。 有趣的是，我们发现斯巴丁蛋白与其相互作用伴侣EPS15一样，参与EGF受体的内在化和降解，预示了斯巴丁在内吞作用中的关键作用。 我们目前正在通过分析我们作为Troyer综合征的鼠模型产生的Spartin-null小鼠来研究Spartin在神经系统中的功能。 此外，我们最近报道了特洛耶综合征的新旧阶阿米什家族的临床特征，并表明从这些患者衍生的细胞中完全不存在spartin蛋白。 在与HSP相关的最终项目中，我们一直在研究复杂的HSP称为MAST综合征（SPG21），这是由酸簇蛋白质肉豆蔻素的大量缺失引起的。 我们已经生成了肉豆蔻蛋白无小鼠作为这种疾病的鼠模型，并且还使用行为技术研究了这些动物，除了使用神经元和其他细胞构成这些动物进行细胞运输研究。 最后，我们最近完成了一项研究，该研究表征了肉豆蔻素蛋白与醛脱氢酶的特定亚型的相互作用，Aldh16a1。 综上所述，我们期望我们的研究将提高我们对HSP分子发病机理的理解。 对分子和细胞水平的这种理解将有望导致新的治疗方法，以防止这些疾病的发展。