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: 8270484
• 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 2014-01-31
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/8270484
• 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

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. 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.

抽象的 肌萎缩性侧索硬化症（ALS）是一种致命的疾病，其特征是变性 和运动神经元的死亡。零星和遗传形式的ALS均遵循常见的致病性 途径，仍然不了解。一个可以解释运动神经元特异性细胞的假设 在ALS和其他类似的神经退行性疾病中观察到的死亡是运动神经元是 对轴突运输中缺陷的独特敏感。沿轴突的主动运输由 微管运动蛋白；而多个驱动蛋白驱动顺行传输，细胞质动力蛋白和 它的激活剂Dynactin是唯一的电动机逆行运输。任何一个 Dynein或Dynactin足以引起运动神经元疾病，表明 维持健康运动神经元的轴突运输。我们现在有直接证明的数据 多种运动神经元疾病模型中逆行转运的明显缺陷，包括 家族性ALS的特征小鼠模型；动力蛋白定位和功能的缺陷作为一个 这些模型中疾病发病机理的早期事件。我们将检查连接缺陷的机制 在轴突运输到神经变性中，重点是逆行效率的改变 运输和运输货物的性质。我们假设这些变化行为 共同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。为了检验这一假设，我们将追求三个具体目标。在 具体目标1，我们将研究疾病发作期间动力蛋白介导的转运如何改变 进展。我们将通过分析蛋白质的运动来研究涉及的特定机制 从神经退行性疾病的小鼠模型中分离出的细胞器。在特定的目标2中，我们将 比较野生型和变性神经元积极运输的赤道， 使用蛋白质组学筛选用于动力蛋白冠。我们假设Dy​​nein Cargos的变化，尤其是 信号分子将导致生存和死亡信号之间的平衡发生变化。最后， 在特定目标3中，我们将使用神经退行性疾病的细胞模型来研究缺陷 在轴突运输中导致神经变性。我们将研究缺陷的相对贡献 运输货物的运输机制和变更，以及Organelle的缺陷 贩运和蛋白质降解。这里提出的研究将导致对 轴突转运在运动神经元退行性疾病中的作用。作为细胞内的破坏 在越来越多的退化性疾病和衰老疾病中观察到贩运 亨廷顿和阿尔茨海默氏病，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见解。沿着神经元延伸轴突的蛋白质，囊泡和细胞器的主动运动称为 轴突运输。这种运输对于神经元的健康和功能至关重要，并且在此过程中存在缺陷 引起运动神经元变性，导致肌营养性侧索硬化症等疾病中的肌肉萎缩 （ALS或Lou Gehrig病）。在这里，我们建议研究轴突中缺陷的机制 运输，直接是由运动蛋白突变引起的，驱动该传输的运动蛋白，或间接地由 其他突变蛋白的表达，导致退化性疾病。