Dynamics of calcium signals control neurotransmitter release in retinal ribbon synapses

钙信号的动力学控制视网膜带突触中神经递质的释放

• 批准号: 10576110
• 负责人: Thirumalini Vaithianathan
• 金额: $ 16.02万
• 依托单位: UNIVERSITY OF TENNESSEE HEALTH SCI CTR
• 依托单位国家: 美国
• 财政年份: 2021
• 资助国家: 美国
• 起止时间: 2021-01-01 至 2025-12-31
• 项目状态: 未结题
• 来源: https://reporter.nih.gov/project-details/10576110
• 关键词: Address; Administrative Supplement; Adult; Applications Grants; Biological Models; Biology; Calcium; Calcium Signaling; Cells; Complex; Computer Models; Data; Defect; Development; Diabetic Neuropathies; Disease; Electron Microscopy; Electrophysiology (science); Funding; Future; Glaucoma; Goals; Health system; Homeostasis; Hour; Individual; Investigation; Kinetics; Knowledge; Laboratories; Measurement; Measures; Molecular; Molecular Target; Monitor; Nerve Degeneration; Neuraxis; Neurons; Neurotransmitters; Organelles; Persons; Pharmacology; Physiological; Process; Property; Proteins; Regulation; Research; Retina; Retinal Degeneration; Retinal Diseases; Rod; Role; Sensory; Signal Transduction; Site; Slice; Speed; Stimulus; Synapses; Synaptic Transmission; Synaptic Vesicles; System; Techniques; Testing; Therapeutic Intervention; Vesicle; Vision; Visual system structure; Zebrafish; age related; analog; base; cytomatrix; experimental study; fluorescence imaging; luminance; millisecond; neurotransmission; neurotransmitter release; novel; optic nerve disorder; prevent; programs; rate of change; recruit; ribbon synapse; segregation; spatiotemporal; stem; therapeutic development; tool; transmission process; visual control; visual information; voltage clamp

Retinal bipolar cells are the first 'projection neurons' of the vertebrate visual system and transmit all of the information needed for vision. Bipolar cells can signal change in contrast while providing an analog read-out of luminance via changing the rate of neurotransmitter release (NTR). To maintain this ability, the bipolar cells must have dynamic control over release rate and the efficient recruitment of release-ready vesicles to fusion sites. However, the spatiotemporal properties of Ca2+ signals that control NTR, and the molecular entities that control the interplay between Ca2+ signal and vesicle dynamics in sustaining kinetically distinct NTR components remain poorly understood. The long-term goal is to unveil the regulation of Ca2+ signaling in retinal ribbon synapses during development, normal adulthood, and disease. Within such goal, the overall objective of this proposal is to determine the spatiotemporal properties of Ca2+ signals that control kinetically distinct pools of NTR and the role of local Ca2+ signals in governing vesicle dynamics that sustain neurotransmission in bipolar cell ribbon synapses. The central hypothesis is that Ca2+ domains governing kinetically distinct components of NTR are different because the ribbon itself adds an additional compartment responsible for spatial segregation of kinetically different synaptic vesicles, and the underlying molecular targets that sense Ca2+ concentration and/or alter Ca2+ signals. This hypothesis is based on preliminary data, acquired in applicant's laboratory using novel techniques developed for evaluating the traffic of single synaptic vesicles at ribbons while simultaneously measuring the underlying changes in [Ca2+], all with millisecond temporal precision. This hypothesis will be tested by pursuing two specific aims using a confluence of state-of-the-art fluorescence imaging, voltage-clamp electrophysiology, computational modeling, electron microscopy of individual physiologically identified cells, and pharmacological tools: 1) Reveal the mechanisms that determine the spatiotemporal properties of calcium signals which control kinetically distinct neurotransmitter release pools; and 2) Determine the interplay between local calcium signaling and vesicle replenishment that is required for sustaining kinetically distinct components of NTR in rod bipolar cell ribbon synapses as a model system. Dysregulation of Ca2+ signaling is a key early– stage process of neurodegeneration in age-related retinal degenerations, glaucoma, diabetic, and optic neuropathies. The knowledge gained from studying Ca2+ dynamics in bipolar cell synaptic transmission will allow us to determine if defects with local Ca2+ homeostasis are a prelude to disease in the future. Data generated from this proposal will have a broad impact that extends beyond our specific investigation of rod bipolar cells but will be applicable to similar ribbon synapses located within and outside the visual system and encoding distinct aspects of sensory information and, more widely, to synapses throughout the central nervous system because the CAZ of ribbon synapses shares many molecular components with conventional synapses.

视网膜双极细胞是脊椎动物视觉系统的第一个“投影神经元”，并传输所有 视力所需的信息。双极单元可能会发出对比的信号变化，同时提供了一个模拟读数的模拟 通过改变神经递质释放速率（NTR）的亮度。为了维持这种能力，双极细胞必须 对释放速率具有动态控制，并有效地募集了释放蔬菜到融合位点。 但是，控制NTR的Ca2+信号的时空特性以及控制的分子实体 Ca2+信号与蔬菜动力学之间的相互作用在维持动力学不同的NTR组件中保持 理解不佳。长期目标是揭示永久性色带突触中Ca2+信号传导的调节 在发育期间，成年正常和疾病。在这样的目标中，该提议的总体目标是 确定CA2+信号的时空特性，该信号控制NTR的动力学不同的池和该角色 在管理蔬菜动力学中，在双极细胞色带中维持神经传递的局部CA2+信号 突触。中心假设是管理NTR的动力学不同组成部分的Ca2+域是 不同，因为色带本身增加了一个额外的隔间，负责空间隔离 动力学上不同的突触蔬菜，以及感知Ca2+浓度和/或的基本分子靶标 更改Ca2+信号。该假设是基于初步数据，该数据是在申请人实验室中使用新颖的数据获得的 开发了用于评估丝带上单个突触蔬菜的流量的技术 测量[Ca2+]的基本变化，所有这些变化都以毫秒的临时精度来测量。该假设将进行检验 通过使用最先进的荧光成像的汇合来追求两个特定的目标，电压钳 电生理学，计算建模，个体物理鉴定的细胞的电显微镜检查，以及 药理学工具：1）揭示确定钙的时空特性的机制 控制动力学上不同的神经递质释放池的信号； 2）确定之间的相互作用 局部钙信号传导和囊泡复制，这是维持动力学不同组分所必需的 杆双极细胞色带突触中的NTR作为模型系统。 CA2+信号传导的失调是早期的关键 与年龄相关的视网膜变性，青光眼，糖尿病和光学的神经变性的阶段过程 神经病。从研究双极细胞突触传输中的Ca2+动力学中获得的知识将允许 我们确定局部Ca2+稳态的缺陷是否是将来疾病的序幕。生成的数据 从该提案中将产生广泛的影响，超出了我们对杆双极细胞的特定研究，但 将适用于位于视觉系统内外的类似的丝带突触，并编码不同的丝带突触 感官信息的各个方面，更广泛地是在整个中枢神经系统中的突触，因为 色带突触的CAZ与常规突触共享许多分子成分。