Defining the roles and regulation of neuronal autophagy

定义神经元自噬的作用和调节

• 批准号: 10894416
• 负责人: Sandra L. Maday
• 金额: $ 4.83万
• 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 2023-08-31
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/10894416
• 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; 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; 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.

项目摘要 自噬是一种溶酶体降解途径，对维持神经元的稳态和存活至关重要。 自噬将受损和老化的细胞组分与细胞内环境和靶点隔离 将它们转移到溶酶体中进行破坏。有缺陷的自噬与神经发育异常有关， 哺乳动物的神经退化此外，激活自噬可以挽救神经变性模型， 小鼠与年龄相关的认知能力下降。然而，对自噬的调节和功能知之甚少 提供神经保护。到目前为止，阐明自噬的分子基础的许多工作都是 在缺乏神经元形态复杂性的模型系统中执行。此外，我们的研究 揭示了几种典型的范式，包括饥饿和mTOR抑制，触发自噬， 非神经元细胞不能强烈地诱导神经元中的自噬。因此，直接研究自噬是至关重要的 在神经元中提供洞察力，可以改善治疗，以减轻神经元功能障碍的疾病。因此，在本发明中， 这项提议的目的是确定神经元自噬的作用和调节， 神经元功能和存活。我们确定神经元中的自噬是一种高度区室化的 过程轴突自噬是一种单向通路，其允许从轴突远端区域递送货物。 轴突到索马的降解。与轴突中自噬的长程途径相反，树突状细胞 自噬是由自噬泡（AV）的双向运动定义的，这种运动可能更加局部化 功能协调发展的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，突触活动控制AV动态选择性树突，而不是在轴突。 我们发现，神经营养因子BDNF诱导逆行自噬流沿着轴突。最后，我们发现， 用星形胶质细胞培养神经元降低了轴突中的自噬体密度。这些的机械基础 然而，其途径和功能尚不清楚。根据我们的初步数据，我们假设， 突触活性、神经营养因子和星形胶质细胞差异性地调节神经元中的自噬， 自噬在神经元功能和存活中起隔室特异性作用。为了验证这个假设， 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）确定神经营养因子如何调节神经元自噬以及自噬如何影响神经元的功能。 影响神经营养因子信号传导;（3）阐明星形胶质细胞如何调节神经元自噬。我们将 在细胞生物学、生物化学和电生理学中使用定量方法， 理解每一条路。这些研究将全面绘制出 自噬是神经元对复杂环境中各种相互作用的反应。获得的新见解 这项研究的结果将更好地为治疗神经系统疾病的治疗干预策略提供信息。