Mechanisms for somatodendritic dopamine release in the midbrain

中脑体细胞树突多巴胺释放机制

• 批准号: 10604832
• 负责人: Pascal Simon Kaeser
• 金额: $ 59.86万
• 依托单位: HARVARD MEDICAL SCHOOL
• 依托单位国家: 美国
• 财政年份: 2023
• 资助国家: 美国
• 起止时间: 2023-03-15 至 2027-12-31
• 项目状态: 未结题
• 来源: https://reporter.nih.gov/project-details/10604832
• 关键词: Ablation; Affect; Architecture; Axon; Behavior; Brain; Brain Diseases; Cells; Characteristics; Cognition; Collection; Complement; Data; Defect; Dendrites; Development; Disease; Dopamine; Drug Addiction; Electrophysiology (science); Emotions; Exocytosis; G-Protein-Coupled Receptors; Glutamates; Goals; Hot Spot; Image; Kinetics; Knockout Mice; Knowledge; Laboratories; Location; Mediating; Membrane; Midbrain structure; Modeling; Molecular; Movement; Mus; Mutant Strains Mice; Nerve; Neuromodulator; Neurons; Neuropeptides; Parkinson Disease; Pathway interactions; Phenotype; Protein Family; Proteins; Receptor Activation; Regulation; Role; Scaffolding Protein; Signal Transduction; Site; Source; Specific qualifier value; Speed; Synapses; Testing; Vesicle; Work; conditional knockout; dopaminergic neuron; drug of abuse; gamma-Aminobutyric Acid; in vivo; knockout gene; monoamine; motor control; mouse genetics; mutant; neuronal excitability; neuropsychiatric disorder; neuroregulation; neurotransmitter release; neurotrophic factor; response; scaffold; secretory protein; sensor; spatiotemporal; superresolution microscopy; synaptotagmin I; tool; transmission process

Summary Many central neurons release neuromodulatory transmitters, for example monoamines, neuropeptides, and neurotrophins, from their somata and dendrites. Release of these transmitters is followed by G-protein coupled receptor activation, and these neuromodulator pathways are essential for brain development and function. Dopamine signaling in the ventral midbrain is a prominent example of this transmission mode, and it is particularly important for the response to drugs of abuse. The knowledge of somatodendritic release and G-protein coupled receptor-mediated transmission lags far behind that of synaptic signaling, but it is often considered slow and imprecise. The long-term goal of this project is to determine the molecular mechanisms that mediate somatodendritic dopamine transmission. We hypothesize that somatodendritic dopamine secretion is mediated by mechanistically specialized machinery for fast and synchronous release. We propose that this machinery is assembled into release hotspots to generate a signal with rapid kinetics that is directed towards G-protein coupled receptor domains on target cells, an architecture ideally suited for robust receptor activation. Our recent work has made first progress towards this goal. We have found that RIM, a protein important for the spatiotemporal precision of axonal transmitter release, is essential for evoked somatodendritic dopamine release. Furthermore, we found that synaptotagmin-1, a fast Ca2+ sensor, mediates Ca2+-triggering of this form of release. We here propose to determine the organization and function of somatodendritic dopamine release machinery using conditional mouse gene knockout, electrophysiology, imaging and superresolution microscopy. In aim 1, we propose to dissect somatodendritic release site architecture in midbrain dopamine neurons. We will systematically test the necessity and localization of five key active zone protein families that control speed and location of exocytosis at classical synapses. In aim 2, we propose to identify Ca2+ sources and sensors for somatodendritic dopamine release. We will assess conditional mouse mutants that lack Ca2+ channel or Ca2+ sensor proteins for secretory deficits and will assess the localization of the proteins needed for Ca2+-triggering in the somatodendritic compartments. These aims will define mechanisms of Ca2+-triggering and are likely to identify active zone-like release hotspots. Our work will further reveal shared and distinct release mechanisms in somatodendritic and axonal compartments of dopamine neurons. This multi-PI project will advance the understanding of somatodendritic dopamine signaling in the midbrain specifically, and of G-protein coupled receptor-mediated transmission in general. It combines the expertise of the laboratories of John Williams and Pascal Kaeser. In-depth studies of these mechanisms will allow us to derive principles and specifications of these neuronal secretory pathways and may ultimately help advancing treatments for diseases with disrupted dopamine function, for example drug addiction.

概括 许多中央神经元释放神经调节发射器，例如单胺，神经肽， 和神经营养蛋白，来自其躯体和树突。这些发射器的释放之后是G蛋白 耦合受体激活，这些神经调节剂途径对于大脑发育至关重要 功能。腹中脑中的多巴胺信号传导是这种传播模式的重要例子，它是 对于对滥用药物的反应特别重要。 somatendritic释放和G蛋白耦合受体介导的传播的知识滞后 在突触信号传导的后面，但通常被认为是缓慢且不精确的。这个长期目标 项目旨在确定介导母源性多巴胺传播的分子机制。 我们假设somatendritic多巴胺分泌是由机械专业的机械介导的 快速和同步释放。我们建议将此机械组装成释放热点以生成 具有快速动力学的信号，该信号针对靶细胞上的G蛋白偶联受体结构域，一个 理想的结构非常适合强大的受体激活。我们最近的工作首先取得了进步 目标。我们发现RIM是一种对轴突发射器释放的时空精度重要的蛋白质， 对于诱发的母源性多巴胺释放至关重要。此外，我们发现Synaptotagmin-1，一个快速 Ca2+传感器，介导这种释放形式的Ca2+触发。 我们在这里建议确定somatendritic多巴胺释放机械的组织和功能 使用有条件的小鼠基因基因敲除，电生理学，成像和分辨率显微镜。在AIM 1中， 我们建议在中脑多巴胺神经元中剖析体内延伸位点结构。我们将 系统地测试控制速度和 胞吐作用在经典突触中的位置。在AIM 2中，我们建议确定CA2+源和传感器 生体多巴胺释放。我们将评估缺乏CA2+通道或Ca2+的有条件小鼠突变体 传感器蛋白用于分泌缺陷，并将评估Ca2+触发所需的蛋白质的定位 在体育室中。这些目标将定义Ca2+触发的机制，并且可能会定义 识别活动区域样释放热点。我们的工作将进一步揭示共享和独特的释放机制 在多巴胺神经元的体内和轴突室中。 这个多PI项目将提高对中脑中母系多巴胺信号的理解 具体而言，通常是G蛋白偶联受体介导的传播。它结合了专业知识 约翰·威廉姆斯（John Williams）和帕斯卡·凯瑟（Pascal Kaeser）的实验室。对这些机制的深入研究将使我们能够 得出这些神经元分泌途径的原则和规格，并最终可能有助于前进 多巴胺功能中断的疾病治疗，例如药物成瘾。