A Drosophila model of motor neuron disease using mutations in P150 / Dynactin.

描述(申请人提供)：肌萎缩侧索硬化症(ALS)是一种致命的运动神经元退行性疾病，没有已知的原因或有效的治疗。我们对肌萎缩侧索硬化症的发病机制缺乏了解，部分原因是缺乏运动神经元变性的简单动物模型。候选人托马斯·劳埃德医学博士建议利用强大的遗传有机体黑腹果蝇来描述和利用一种新的运动神经元疾病模型。新出现的数据表明，轴突运输缺陷或其他囊泡运输事件可能是这种疾病的主要原因。为了研究囊泡运输在运动神经元疾病中的作用，我们在果蝇中引入了dynactin P150亚单位的突变，这种突变存在于一种罕见的家族性ALS中。表达突变P150的果蝇有几种表型使人想起ALS，包括突变蛋白聚集，轴突运输缺陷，以及成年发病、进行性瘫痪和早期死亡。这项提议的目的是进一步描述运动神经元疾病的这种简单的遗传模型，然后用它来筛选运动神经元变性的遗传抑制因子。目的1研究疾病相关的P150基因突变对果蝇体内囊泡运输的影响，以验证这些突变破坏特定囊泡运输过程的假说。目的2将验证与疾病相关的P150突变导致运动神经元和神经肌肉接头病理类似于ALS患者的假设。目的3将首先表征一个已识别的突变型P150抑制子对这些运动神经元表型的影响。然后，我们将在果蝇基因组中筛选突变P150的额外遗传修饰物，希望识别对疾病发病机制至关重要的新基因，这是一种在小鼠模型中不可行的有效方法。已识别的遗传相互作用因子是潜在的药物靶点，因此这项提议的未来方向是验证已识别的ALS小鼠模型中的相互作用基因。拟议的研究将在Alex Kolodkin的实验室进行，Alex Kolodkin是果蝇和小鼠运动神经元连接方面的专家，Robert Packard ALS研究中心主任Jeff Rothstein将提供指导。约翰霍普金斯大学的神经科学和神经病学系为学术神经学家的发展提供了一个特殊的环境。这笔赠款提供的培训和指导将为劳埃德博士提供所需的专业知识和工具，使他成为一名成功的、独立的内科科学家，他将致力于寻找ALS的新疗法。 相关性：由于缺乏这种疾病的简单动物模型，ALS治疗方法的发展受到阻碍。这项提议将描述ALS的一种新的果蝇模型，以帮助了解ALS的遗传原因，并帮助寻找治疗这种毁灭性疾病的新药物靶点。

DESCRIPTION (provided by applicant): Amyotrophic Lateral Sclerosis (ALS) is a fatal neurodegenerative disease of motor neurons without a known cause or effective treatment. Our poor understanding of ALS pathogenesis is partly due to a lack of simple animal models of motor neuron degeneration. The candidate, Thomas Lloyd M.D., Ph.D. proposes to characterize and utilize a novel model of motor neuron disease using the powerful genetic organism Drosophila melanogaster. Emerging data suggest that defects in axonal transport or other vesicle trafficking events may be a primary cause of this disease. To investigate the role of vesicle transport in motor neuron disease, we have introduced a mutation in the P150 subunit of dynactin into Drosophila that is present in a rare familial form of ALS. Flies expressing mutant P150 have several phenotypes reminiscent of ALS including aggregates of mutant protein, defects in axonal transport, and adult-onset, progressive paralysis and early death. The goal of this proposal is to further characterize this simple genetic model of motor neuron disease, and then to use it to screen for genetic suppressors of motor neuron degeneration. Aim 1 will investigate the effects of disease-associated P150 mutations on vesicle transport in Drosophila in vitro and in vivo to test the hypothesis that these mutations disrupt specific vesicle transport processes. Aim 2 will test the hypothesis that disease-associated P150 mutations cause motor neuron and neuromuscular junction pathology resembling that seen in ALS patients. Aim 3 will first characterize the effect of an identified suppressor of mutant P150 on these motor neuron phenotypes. We will then screen the Drosophila genome for additional genetic modifiers of mutant P150 in hopes of identifying novel genes critical to disease pathogenesis, a powerful approach not feasible in mouse models. Identified genetic interactors are potential drug targets, so a future direction of this proposal is to validate identified interacting genes in mouse models of ALS. The studies proposed will be carried out in the laboratory of Alex Kolodkin, an expert in motor neuron connectivity in Drosophila and mice, with mentorship from Jeff Rothstein, Director of the Robert Packard Center for ALS Research. The neuroscience and neurology departments at Johns Hopkins provide an exceptional environment for the development of academic neurologists. The training and mentorship provided by this grant will give Dr. Lloyd the expertise and tools needed to become a successful, independent physician-scientist who will devote his career to identifying new treatments for ALS. RELEVANCE: The development of treatments for ALS is hindered by the lack of simple animal models of this disease. This proposal will characterize a new fruitfly model of ALS to help understand the genetic causes of ALS and to help find new drugs targets for this devastating disease.