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: 8079649
• 负责人: Erika L Holzbaur
• 金额: $ 33.76万
• 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/8079649
• 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; Disease Progression; 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; Onset of illness; Organelles; Pathogenesis; Pathway interactions; Process; Proteins; Proteomics; 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.

摘要肌萎缩性侧索硬化症（Amyotrophic lateral sclerosis， ALS）是一种以运动神经元变性和死亡为特征的绝症和不治之症。散发性和遗传性ALS都遵循一种共同的致病途径，这一途径尚不清楚。一种可能解释ALS和其他类似神经退行性疾病中观察到的运动神经元特异性细胞死亡的假设是，运动神经元对轴突运输缺陷非常敏感。轴突主动转运由微管运动蛋白驱动；虽然有多种动力蛋白驱动逆行运输，但细胞质动力蛋白及其激活剂动力蛋白是唯一驱动逆行运输的马达。动力蛋白或动力蛋白的显性突变足以引起运动神经元疾病，这表明轴突运输在维持运动神经元健康方面的重要性。我们现在有数据直接表明，在运动神经元疾病的多种模型中，逆行运输存在显著缺陷，包括一个具有良好特征的家族性ALS小鼠模型；在这些模型中，动力蛋白定位和功能缺陷是疾病发病的早期事件。我们将研究轴突运输缺陷与神经退行性变的联系机制，重点关注逆行运输效率和被运输货物性质的改变。我们假设这些变化共同作用，导致神经元中生存和死亡信号平衡的改变，导致神经元变性和细胞死亡。为了验证这一假设，我们将追求三个具体目标。在特异性目标1中，我们将研究动力蛋白介导的转运在疾病发病和进展过程中是如何改变的。我们将通过分析从小鼠神经退行性疾病模型中分离的蛋白质和细胞器的运动来研究所涉及的具体机制。在特异性目标2中，我们将比较野生型和退化神经元中动力蛋白主动运输的货物，使用蛋白质组学筛选动力蛋白货物。我们假设动力蛋白货物的变化，特别是信号分子的变化，将导致生存和死亡信号之间平衡的改变。最后，在Specific Aim 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缺陷如何导致神经退行性变。我们将研究运输机械缺陷和运输货物变化的相对贡献，以及细胞器运输和蛋白质降解的缺陷。这里提出的研究将导致更清楚地了解轴突转运在运动神经元退行性疾病中的作用。随着越来越多的退行性和老化性疾病（包括亨廷顿氏病和阿尔茨海默病）中观察到细胞内运输的破坏，这里提出的机制研究可能会提供更广泛适用于我们对神经元变性的理解的见解。公共卫生相关性：蛋白质、囊泡和细胞器沿神经元延伸轴突的活跃运动被称为轴突运输。这种转运对神经元的健康和功能至关重要，而这一过程中的缺陷会导致运动神经元退化，从而导致肌萎缩性侧索硬化症（ALS或Lou Gehrig's Disease）等疾病中的肌肉萎缩。在这里，我们建议研究轴突运输缺陷的机制，这些缺陷要么直接由驱动这种运输的运动蛋白的突变引起，要么间接由其他突变蛋白的表达引起，从而导致退行性疾病。