Defining the roles and regulation of neuronal autophagy

定义神经元自噬的作用和调节

• 批准号: 10598406
• 负责人: Sandra L. Maday
• 金额: $ 6.74万
• 依托单位: UNIVERSITY OF PENNSYLVANIA
• 依托单位国家: 美国
• 财政年份: 2020
• 资助国家: 美国
• 起止时间: 2020-05-15 至 2025-03-31
• 项目状态: 未结题
• 来源: https://reporter.nih.gov/project-details/10598406
• 关键词: Affect; Age-associated memory impairment; Astrocytes; Autophagocytosis; Autophagosome; Axon; Biochemistry; Biological Models; Biology; Birth; Brain-Derived Neurotrophic Factor; Cells; Cellular biology; Coculture Techniques; Complex; Cues; Data; Defect; Degradation Pathway; Dendrites; Disease; Distant; Electrophysiology (science); Environment; Gene Expression; Genes; Goals; Hippocampus (Brain); Homeostasis; Human; Lead; Learning; Link; Lysosomes; Mammals; Maps; Measures; Mediating; Memory; Metabolism; Modeling; Molecular; Morphology; Movement; Mus; Mutation; Nerve Degeneration; Neurodegenerative Disorders; Neuroglia; Neuronal Dysfunction; Neurons; Neurosciences; Outcome; Pathway interactions; Phenotype; Play; Population; Presynaptic Terminals; Process; Property; Regulation; Research; Role; Signal Transduction; Starvation; Stress; Synapses; Techniques; Testing; Therapeutic; Therapeutic Intervention; Time; Translations; Vacuole; Work; aged; base; cell motility; density; experimental study; improved; insight; knock-down; mTOR inhibition; nervous system disorder; neuron development; neuronal cell body; neuronal survival; neuroprotection; neurotrophic factor; polarized cell; postsynaptic; programs; response; retrograde transport; synaptic function

PROJECT SUMMARY Autophagy is a lysosomal degradation pathway that is critical to maintain neuronal homeostasis and survival. Autophagy sequesters damaged and aged cellular components from the intracellular environment and targets them to lysosomes for destruction. Defective autophagy is linked to neurodevelopmental abnormalities and neurodegeneration in mammals. Further, activating autophagy can rescue models of neurodegeneration and age-related cognitive decline in mice. Little is known, however, about the regulation and functions of autophagy that provide neuroprotection. Much of the work to date elucidating the molecular basis of autophagy has been performed in model systems that lack the morphological complexity of neurons. Further, our research has revealed that several canonical paradigms, including starvation and mTOR-inhibition, that trigger autophagy in non-neuronal cells do not robustly induce autophagy in neurons. Thus, it is critical to study autophagy directly in neurons to provide insight that may improve therapies to mitigate diseases of neuronal dysfunction. Thus, the objective for this proposal is to define the roles and regulation of neuronal autophagy that facilitate neuronal function and survival. We established that autophagy in neurons is a highly compartmentalized process. Axonal autophagy is a unidirectional pathway that allows cargo delivery from distant regions of the axon to the soma for degradation. In contrast to the long-range pathway for autophagy in axons, dendritic autophagy is defined by bidirectional movement of autophagic vacuoles (AVs) that may execute more localized functions. Our preliminary data have identified three aspects of neuronal biology (synaptic connectivity, neurotrophic support, and interactions with astrocytes) that regulate autophagy in specific neuronal compartments. We find that synaptic activity controls AV dynamics selectively in dendrites and not in the axon. We find that the neurotrophin BDNF induces retrograde autophagic flux along axons. Lastly, we find that co- culturing neurons with astrocytes decreases autophagosome density in axons. The mechanistic basis for these pathways and their functions, however, are unknown. Based on our preliminary data, we hypothesize that synaptic activity, neurotrophins, and astrocytes differentially regulate autophagy in neurons, and, that autophagy plays compartment-specific roles in neuronal function and survival. To test this hypothesis, we will pursue three aims: (1) Define how synaptic activity regulates neuronal autophagy and how autophagy affects synapse function; (2) Determine how neurotrophins regulate neuronal autophagy and how autophagy impacts neurotrophin signaling; and (3) Elucidate how neuronal autophagy is regulated by astrocytes. We will use quantitative approaches in cell biology, biochemistry, and electrophysiology to gain a mechanistic understanding for each pathway. These studies will comprehensively map the pathways and functions for autophagy in neurons in response to diverse interactions from their complex environment. New insights gained from this study will better inform strategies for therapeutic intervention to treat disorders of the nervous system.

项目概要 自噬是一种溶酶体降解途径，对于维持神经元稳态和生存至关重要。 自噬将受损和老化的细胞成分与细胞内环境和靶标隔离开来 它们被溶酶体破坏。自噬缺陷与神经发育异常有关 哺乳动物的神经变性。此外，激活自噬可以挽救神经退行性疾病模型 小鼠中与年龄相关的认知能力下降。然而，人们对自噬的调控和功能知之甚少 提供神经保护。迄今为止，阐明自噬分子基础的大部分工作都是 在缺乏神经元形态复杂性的模型系统中进行。此外，我们的研究还 揭示了几种典型的范例，包括饥饿和 mTOR 抑制，可以触发自噬 非神经元细胞不会强烈诱导神经元中的自噬。因此，直接研究自噬至关重要 在神经元中提供洞察力，可以改善减轻神经元功能障碍疾病的治疗方法。因此， 该提案的目标是定义神经元自噬的作用和调节，以促进 神经元功能和存活。我们确定神经元中的自噬是高度分化的 过程。轴突自噬是一种单向途径，允许从远处区域输送货物 轴突到胞体进行降解。与轴突中自噬的长程途径相反，树突状 自噬是通过自噬液泡（AV）的双向运动来定义的，它可以执行更局部的 功能。我们的初步数据已经确定了神经元生物学的三个方面（突触连接、 神经营养支持以及与星形胶质细胞的相互作用）调节特定神经元的自噬 隔间。我们发现突触活动选择性地控制树突中的 AV 动力学，而不是轴突中的。 我们发现神经营养蛋白 BDNF 诱导沿轴突的逆行自噬流。最后，我们发现共同 用星形胶质细胞培养神经元会降低轴突中自噬体的密度。这些的机制基础 然而，途径及其功能尚不清楚。根据我们的初步数据，我们假设 突触活动、神经营养蛋白和星形胶质细胞差异性地调节神经元中的自噬，并且 自噬在神经元功能和存活中发挥着特定的作用。为了检验这个假设， 我们将追求三个目标：（1）定义突触活动如何调节神经元自噬以及自噬如何 影响突触功能； (2)确定神经营养素如何调节神经元自噬以及自噬如何进行 影响神经营养素信号传导； (3)阐明星形胶质细胞如何调节神经元自噬。我们将 使用细胞生物学、生物化学和电生理学中的定量方法来获得机制 对每条途径的理解。这些研究将全面绘制出以下途径和功能： 神经元中的自噬响应复杂环境中的多种相互作用。获得新的见解 这项研究将更好地为治疗神经系统疾病的治疗干预策略提供信息。