Mechanistic analysis of axonal transport defects in motor neuron degenerative dis

运动神经元退行性疾病轴突运输缺陷的机制分析

• 批准号: 7524459
• 负责人: Erika L Holzbaur
• 金额: $ 34.45万
• 依托单位: UNIVERSITY OF PENNSYLVANIA
• 依托单位国家: 美国
• 财政年份: 2008
• 资助国家: 美国
• 起止时间: 2008-07-01 至 2013-06-30
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/7524459
• 关键词: Active Biological Transport; Aging; Alzheimer' s Disease; Amyotrophic Lateral Sclerosis; Automobile Driving; Axon; Axonal Transport; Cell Death; Cell model; Cells; Cessation of life; Complex; Data; Defect; Degenerative Disorder; Disease; Disruption; Dynein ATPase; Equilibrium; Event; Familial Amyotrophic Lateral Sclerosis; Health; Human; Huntington Disease; Inherited; Intracellular Transport; Kinesin; Lead; Link; Mediating; Microtubules; Modeling; Motor; Motor Neuron Disease; Motor Neurons; Movement; Mus; Muscular Atrophy; Mutation; Nature; Nerve Degeneration; Neurodegenerative Disorders; Neurons; Numbers; Onset of illness; Organelles; Pathogenesis; Pathway interactions; Process; Proteins; Proteomics; Public Health; Rate; Relative (related person); Role; Signal Transduction; Signaling Molecule; Testing; Vesicle; abstracting; anterograde transport; base; cell motility; dynactin; insight; motor neuron degeneration; mouse model; mutant; protein degradation; retrograde transport; trafficking

DESCRIPTION (provided by applicant): Abstract Amyotrophic lateral sclerosis (ALS) is a fatal and incurable disease characterized by the degeneration and death of motor neurons. Both sporadic and inherited forms of ALS follow a common pathogenic pathway, which is still not understood. One hypothesis that may explain the motor neuron-specific cell death observed in ALS and other similar neurodegenerative diseases is that motor neurons are uniquely sensitive to defects in axonal transport. Active transport along the axon is driven by microtubule motor proteins; while multiple kinesins drive anterograde transport, cytoplasmic dynein and its activator dynactin are the only motor driving retrograde transport. Dominant mutations in either dynein or dynactin are sufficient to cause motor neuron disease, demonstrating the importance of axonal transport in maintaining healthy motor neurons. We now have data directly demonstrating significant defects in retrograde transport in multiple models of motor neuron disease, including a well- characterized mouse model of familial ALS; defects in dynein localization and function occur as an early event in disease pathogenesis in these models. We will examine the mechanisms linking defects in axonal transport to neurodegeneration, focusing on alterations in both the efficiency of retrograde transport and the nature of the cargos being transported. We hypothesize that these changes act together to lead to alterations in the balance of survival and death signals in the neuron, resulting in neuronal degeneration and cell death. To test this hypothesis, we will pursue three specific aims. In Specific Aim 1, we will look at how dynein-mediated transport is altered during disease onset and progression. We will investigate the specific mechanisms involved by analyzing the motility of proteins and organelles isolated from mouse models of neurodegenerative disease. In Specific Aim 2, we will compare the cargos that are actively transported by dynein in wild type and degenerating neurons, using proteomic screens for dynein cargos. We hypothesize that changes in dynein cargos, especially signaling molecules, will result in alterations in the balance between survival and death signals. Finally, in Specific Aim 3, we will use cellular models of neurodegenerative disease to investigate how defects in axonal transport lead to neurodegeneration. We will examine the relative contributions of defects in the transport machinery and alterations in the cargo being transported, as well as defects in organelle trafficking and protein degradation. The studies proposed here will lead to a clearer understanding of the role of axonal transport in motor neuron degenerative disease. As disruption of intracellular trafficking has been observed in a growing number of degenerative and aging diseases, including Huntington's and Alzheimer's Disease, it is likely that the mechanistic studies proposed here will provide insights that are more broadly applicable to our understanding of neuronal degeneration. PUBLIC HEALTH RELEVANCE: The active movement of proteins, vesicles, and organelles along the extended axons of neurons is called axonal transport. This transport is essential for the health and function of the neuron, and defects in the process cause motor neuron degeneration leading to muscle atrophy in diseases such as Amyotrophic Lateral Sclerosis (ALS or Lou Gehrig's Disease). Here, we propose to investigate the mechanisms by which defects in axonal transport, caused either directly by mutations in the motor proteins that drive this transport, or indirectly by the expression of other mutant proteins, lead to degenerative disease.

描述（由申请人提供）：摘要肌萎缩性侧面硬化症（ALS）是一种致命的疾病，其特征是运动神经元的退化和死亡。 ALS的零星和遗传形式都遵循一种常见的致病途径，但仍未理解。一个假设可以解释在ALS和其他类似的神经退行性疾病中观察到的运动神经元特异性细胞死亡，这是运动神经元对轴突转运中的缺陷非常敏感。沿轴突的主动转运由微管运动蛋白驱动；虽然多个驱动蛋白驱动顺行传输，但细胞质动力蛋白及其活化剂dynactin是唯一的运动逆行转运。 Dynein或Dynactin中的主要突变足以引起运动神经元疾病，这表明轴突运输在维持健康的运动神经元中的重要性。现在，我们有数据直接显示出多种运动神经元疾病模型的逆行转运中的明显缺陷，包括良好的家族性ALS小鼠模型。在这些模型中，动力蛋白定位和功能的缺陷是疾病发病机理的早期事件。我们将检查将轴突运输中缺陷与神经变性联系起来的机制，重点是逆行运输效率和正在运输的千圈的性质的改变。我们假设这些变化共同起作用，导致神经元中生存和死亡信号平衡的改变，从而导致神经元变性和细胞死亡。为了检验这一假设，我们将追求三个具体目标。在特定目标1中，我们将研究在疾病发作和进展过程中如何改变动力蛋白介导的转运。我们将通过分析从神经退行性疾病的小鼠模型中分离出的蛋白质和细胞器的运动性来研究所涉及的特定机制。在特定的目标2中，我们将使用蛋白质组学筛选用于动力蛋白的cargos，比较通过野生型和退化神经元积极运输的碳。我们假设动力蛋白碳，尤其是信号分子的变化将导致生存和死亡信号之间的平衡发生变化。最后，在特定的目标3中，我们将使用神经退行性疾病的细胞模型来研究轴突运输中的缺陷如何导致神经变性。我们将研究运输机制中缺陷的相对贡献和运输货物的变化，以及细胞器贩运和蛋白质降解的缺陷。这里提出的研究将使人们对轴突转运在运动神经元退行性疾病中的作用有更清晰的了解。由于在包括亨廷顿和阿尔茨海默氏病在内的越来越多的退化性和衰老疾病中观察到了细胞内贩运的破坏，因此这里提出的机械研究可能会提供更广泛地适用于我们对神经元变性的理解。公共卫生相关性：蛋白质，囊泡和细胞器沿神经元延伸的轴突的主动运动称为轴突运输。这种转运对于神经元的健康和功能至关重要，并且该过程中的缺陷导致运动神经元变性，从而导致肌营养性侧面硬化症（ALS或Lou Gehrig病）等疾病中的肌肉萎缩。在这里，我们建议研究轴突转运中缺陷的机制，直接是由驱动该转运的运动蛋白突变引起的，或间接地是由于其他突变蛋白的表达而导致退化性疾病。