Hereditary Spastic Paraplegia due to SPG3A/atlastin mutation

SPG3A/atlastin 突变导致的遗传性痉挛性截瘫

• 批准号: 7147885
• 负责人: JOHN K. FINK
• 金额: $ 33.65万
• 依托单位: UNIVERSITY OF MICHIGAN AT ANN ARBOR
• 依托单位国家: 美国
• 财政年份: 2006
• 资助国家: 美国
• 起止时间: 2006-07-15 至 2010-04-30
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/7147885
• 关键词: clinical research; culture; family; gene mutation; genes; model; neurons; paraplegia; phenotype; proteins

DESCRIPTION (provided by applicant): The Hereditary Spastic Paraplegias (HSPs) are degenerative spinal cord disorders that cause disabling lower extremity spastic weakness. Recently, we discovered mutations in a novel gene (SPGSA/atlastin) as the cause of autosomal dominant SPG3A HSP. This advance has been translated into a clinically available diagnostic test for HSP and provides opportunities to expose HSP's molecular pathophysiology. Our proposal builds on this progress and focuses on 1) defining the SPG3A HSP phenotype and correlating clinical variatipn with SPG3A mutations and HSP modifying-gene polymorphisms; 2) understanding SPGSA/atlastin function by identifying its interacting factors; and 3) studying SPG3A pathogenesis in in vitro and animal models. Specific Aim 1 will characterize the phenotype and examine the basis of clinical variation in SPG3A HSP. The SPG3A phenotype can be quite variable and include childhood- and adult-onset uncomplicated HSP and HSP associated with lower motor neuron signs. Although clinical variation sometimes correlates with discrete SPGSA/atlastin mutation, variation between subjects with the same mutation indicates the action of modifying factors. There is precedent for benign HSP gene polymorphism to modify the HSP phenotype. Therefore, in addition to correlating SPG3A HSP phenotype variation with discrete SPG3A mutations, Specific Aim 1 will assess benign polymorphisms in SPGSA/atlastin, SPG4/spastin, and other HSP genes as "candidate modifying factors". Identifying disease modifying genes in HSP will expand our knowledge of HSP pathogenesis. Determining the SPGSA/atlastin genotype-phenotype correlations will suggest SPG3A functional domains and contribute to our studies of factors that interact with atlastin. Specific Aim 2 will provide insight into the function of SPGSA's encoded protein "atlastin" by identifying its interacting factors. Presently, clues to atlastin's function come from 3 sources: 1) its localization to cis-golgi membranes of cortical motor neurons; 2) it's homology to guanylate binding protein 1, a member of the dynamin family of GTPases that play essential roles in a wide variety of endosome trafficking events; and 3) its reported interaction in vitro with HPK/GCK-like kinase (HGK), a protein kinase in the c-Jun N-terminal kinase signaling (JNK) pathway. Specific Aim 2 will identify and analyze atlastin interacting proteins, investigate the reported atlastin-HGK interaction, and determine whether HSP-specific SPGSA/atlastin mutations change the proteins with which atlastin interacts. Specific Aim 3 will examine SPGSA/atlastin pathogenesis in vitro and in vivo. In view of atlastin's localization to cis-golgi, we are particularly interested in examining Golgi structure and function in in vitro and in vivo models. We will study morphology, differentiation, and atlastin intracellular location of cultured neurons bearing SPGSA/atlastin insufficiency (created through RNAi methods); and those with overexpression of wild-type and mutant SPG3A cDNA. We will study the behavior and neuropathology of SPGSA/atlastin mutation mice already created in our laboratory. Preliminary analysis of these animals reveals age-dependent hind limb motor impairment. By identifying SPG3A genotype-phenotype correlations, discovering SPGSA/atlastin-interacting factors, exposing metabolic cascades in which atlastin interacts, and examining in vitro and in vivo models of HSP, this investigation will provide insight into the causes and ultimately treatments for HSP and other motor neuron diseases including amyotrophic lateral sclerosis.

描述（由申请人提供）：遗传性痉挛性截瘫（HSP）是退行性脊髓疾病，可导致下肢痉挛性无力致残。最近，我们发现一个新的基因（SPGSA/atlastin）的突变是常染色体显性SPG 3A HSP的原因。这一进展已转化为临床可用的HSP诊断测试，并提供了机会，暴露HSP的分子病理生理学。我们的建议建立在这一进展的基础上，重点是1）定义SPG 3A HSP表型，并将临床变异与SPG 3A突变和HSP修饰基因多态性相关联; 2）通过识别其相互作用因子来理解SPGSA/atlastin功能; 3）在体外和动物模型中研究SPG 3A发病机制。特异性目的1将表征SPG 3A HSP的表型并检查临床变异的基础。SPG 3A表型可以是相当可变的，包括儿童期和成人期发病的单纯HSP和与下运动神经元体征相关的HSP。虽然临床变异有时与离散SPGSA/atlastin突变相关，但具有相同突变的受试者之间的变异表明修饰因子的作用。良性HSP基因多态性改变HSP表型已有先例。因此，除了将SPG 3A HSP表型变异与离散的SPG 3A突变相关联之外，具体目标1将评估SPGSA/atlastin、SPG 4/spastin和其他HSP基因中的良性多态性作为“候选修饰因子”。确定HSP中的疾病修饰基因将扩大我们对HSP发病机制的认识。确定SPGSA/atlastin基因型-表型的相关性将建议SPG 3A功能域，并有助于我们的研究与atlastin相互作用的因素。具体目标2将提供深入了解SPGSA的编码蛋白“atlastin”的功能，通过确定其相互作用的因素。目前关于atlastin功能的线索有3个来源：1）它定位于皮质运动神经元的顺式高尔基体膜; 2）它与鸟苷酸结合蛋白1同源，鸟苷酸结合蛋白1是动力蛋白家族的一员，在各种各样的内体运输事件中起重要作用;和3）其在体外与HPK/GCK样激酶（HGK）（c-Jun N-末端激酶信号传导（JNK）途径中的蛋白激酶）的报道的相互作用。具体目标2将确定和分析atlastin相互作用的蛋白质，调查报告atlastin-HGK相互作用，并确定是否HSP特异性SPGSA/atlastin突变改变与atlastin相互作用的蛋白质。具体目标3将在体外和体内研究SPGSA/atlastin的发病机制。鉴于atlastin的本地化顺式高尔基体，我们特别感兴趣的是在体外和体内模型中检查高尔基体的结构和功能。我们将研究形态，分化，和atlastin细胞内的位置培养的神经元轴承SPGSA/atlastin不足（通过RNAi方法创建）;和野生型和突变SPG 3A cDNA的过表达。我们将研究我们实验室已经创建的SPGSA/atlastin突变小鼠的行为和神经病理学。对这些动物的初步分析揭示了年龄依赖性后肢运动障碍。通过鉴定SPG 3A基因型-表型相关性，发现SPGSA/atlastin相互作用因子，暴露atlastin相互作用的代谢级联反应，以及检查HSP的体外和体内模型，这项调查将为HSP和其他运动神经元疾病（包括肌萎缩侧索硬化症）的病因和最终治疗提供深入了解。