The Nigral Molecular Clock and Vulnerability to Neurodegeneration

黑质分子钟和神经退行性疾病的脆弱性

• 批准号: 10383744
• 负责人: Rita Marie Cowell
• 金额: $ 47.36万
• 依托单位: UNIVERSITY OF ALABAMA AT BIRMINGHAM
• 依托单位国家: 美国
• 财政年份: 2018
• 资助国家: 美国
• 起止时间: 2018-07-15 至 2024-04-30
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/10383744
• 关键词: ARNTL gene; Age; Aging; Animal Model; Attenuated; Autophagocytosis; Bacterial Artificial Chromosomes; Behavioral; Calcium; Cells; Cessation of life; Characteristics; Circadian Dysregulation; Data; Disease; Disease Progression; Doxycycline; Electrophysiology (science); Evaluation; Fluorescent in Situ Hybridization; Frequencies; Functional disorder; Future; Gene Expression; Genetic Transcription; Homeostasis; Image; Impairment; Lewy Bodies; Luciferases; Maintenance; Mediating; Metabolism; Midbrain structure; Mitochondria; Modeling; Molecular; Movement Disorders; Mus; Nerve Degeneration; Neurodegenerative Disorders; Neuronal Dysfunction; Neurons; Parkinson Disease; Pathogenesis; Pathologic; Pathology; Pathway interactions; Periodicity; Phenotype; Physiological; Population; Prevention; Prevention strategy; Process; Proteins; Role; Sodium; Substantia nigra structure; Synapses; System; Techniques; Testing; Tetanus Helper Peptide; Time; Transcriptional Regulation; Transgenic Mice; Transgenic Organisms; Variant; alpha synuclein; behavioral impairment; cell injury; circadian; circadian pacemaker; design; dopaminergic neuron; experimental study; insight; molecular clock; motor behavior; motor impairment; mouse model; mouse synuclein alpha; neuron loss; neurotoxicity; novel; overexpression; pars compacta; programs; protein aggregation; regenerative; single molecule; stressor; suprachiasmatic nucleus; synuclein; tool; trafficking

Dopaminergic neurons of the substantia nigra are particularly susceptible to dysfunction and loss with aging and disease. A potential contributor to this vulnerability is the requirement for the maintenance of intrinsic pacemaking activity. However, little is known about how this pacemaking activity is regulated in physiological and pathological states. Understanding how nigral neurons maintain their firing rate and adapt to cellular stressors has the potential to reveal novel pathways for prevention of cellular damage and death. In this application, we are proposing to test the novel hypotheses that the molecular clock is a key regulator of pacemaking activity and other processes required for normal function of dopaminergic neurons and that disruption of this clock contributes to cell dysfunction and death in models of Parkinson Disease (PD). In support of these hypotheses, we have found that dopaminergic neuron firing rate varies with time of day and that this variation is abolished in mice with midbrain-specific deletion of the obligate transcriptional regulator of circadian function, Bmal1. Furthermore, we have found day/night differences in the expression of genes involved in pacemaking activity in the substantia nigra, suggesting that pathways important for nigral function may be regulated at the transcriptional level by the molecular clock. Interestingly, we have discovered alpha synuclein mouse models of PD display disrupted day/night differences in pacemaking activity, leading to the hypothesis that the impairment of circadian-regulated processes could contribute to neuronal dysfunction and death in disease. In Aim 1, experiments are designed to determine the mechanisms by which the molecular clock regulates dopaminergic neuron function at the transcriptional, electrophysiological, and behavioral levels, using recently developed tools to evaluate molecular clock rhythmicity and transcription in a cell-specific way. In Aim 2, experiments will utilize approaches to reset the molecular clock in a time-of-day-dependent manner in mice with α-synuclein- induced pathology to determine the role for circadian dysregulation in the progression of α-synuclein-mediated neurotoxicity and behavioral impairment. Altogether, these experiments have the potential to reveal a novel regulatory mechanism of nigral function and vulnerability and could give critical insight into disease progression and pathogenesis.

黑质的多巴胺能神经元特别容易受到功能障碍和衰老的损失 和疾病。对这种脆弱性的潜在贡献是维持内在的要求 起搏活动。但是，关于这种起搏活动如何在生理中调节的知之甚少 和病理状态。了解ni骨神经元如何保持发射速率并适应细胞 Stresors有可能揭示预防细胞损伤和死亡的新途径。在这个 应用，我们提议测试新的假设，即分子时钟是 多巴胺能神经元正常功能所需的起搏活动和其他过程 该时钟的破坏导致帕金森氏病（PD）模型中的细胞功能障碍和死亡。在 支持这些假设，我们发现多巴胺能神经输血率随着一天的时间和 在小鼠中，这种变异被以中脑特异性删除的义务转录调节器的特定于中脑的差异 昼夜节律功能，BMAL1。此外，我们发现了基因表达的白天/夜晚差异 参与黑质中的起搏活动，表明途径对nigral功能很重要 可以通过分子时钟在转录水平调节。有趣的是，我们发现了Alpha PD的突触核蛋白鼠标模型在起搏活动中表现出残疾的白天/夜晚差异，导致 假设昼夜节律调节过程的损害可能导致神经元功能障碍和 疾病死亡。在AIM 1中，设计实验旨在确定分子的机制 时钟调节在转录，电生理和行为水平上的多巴胺能神经元功能， 使用最近开发的工具以细胞特异性的方式评估分子时钟的节奏性和转录。 在AIM 2中，实验将采用方法以日期依赖的方式重置分子时钟 患有α-突触核蛋白诱导病理学的小鼠确定昼夜节律失调在进展中的作用 α-突触核蛋白介导的神经毒性和行为障碍。总共，这些实验具有 有可能揭示新型的ni骨功能和脆弱性的调节机制，并可能给出关键 深入了解疾病进展和发病机理。