Dynamics of calcium signals control neurotransmitter release in retinal ribbon synapses.

项目摘要 痴呆，包括与阿尔茨海默病（AD）相关的痴呆，是主要的神经退行性疾病 由于视网膜、视神经和高级皮质的病理变化而导致视觉问题 损伤在AD中，这些变化包括对比敏感度、视力和色觉的变化。尽管 越来越多的人认为视网膜可用于AD的早期诊断，但对AD的潜在机制知之甚少。 与AD组织病理学标志物和视力损害相关的机制。这些机制必须 为开发有效的AD治疗方法而破译。视网膜中的感觉突触依赖于 突触带的正常功能，这是一个专门的细胞器锚定到突触前活性 区突触功能障碍（突触病）是一种重要的共同生物学机制， 病理学到AD症状。我们父母研究计划的长期目标是揭示 在发育、正常成年期和疾病状态期间视网膜带状突触中的Ca2+信号传导影响 视网膜而在家长研究计划的重点是当地的Ca2+信号及其相互作用， 囊泡补充所需的神经递质释放，补充研究计划将适用 这些知识AD。我们对这两个项目的方法都使用了最先进的技术，包括 荧光成像，电压钳电生理学，计算建模， 个体生理学鉴定的细胞和药理学工具。我们将使用一个新颖而强大的模型， 用冈田酸（OKA）处理的成年斑马鱼中的AD表现出重要AD的整体表现 标志并复制AD的记忆缺陷。我们的中心假设是AD组织病理学 在OKA处理的斑马鱼视网膜中发展的标志导致功能障碍的发生和进展 通过改变突触囊泡的移动性、线粒体功能和钙离子浓度， 失调我们的假设得到了最近研究的支持，在这些研究中，OKA治疗斑马鱼导致 AD的主要组织病理学标志的形成，包括淀粉样β（Aβ）蛋白片段， 神经纤维缠结（NFT）、过度磷酸化的tau蛋白和老年斑的积累，导致 神经变性、认知障碍、氧化应激、神经炎症、胶质细胞活化、谷氨酸 兴奋性毒性和线粒体功能障碍。在目标1中，我们将确定突触囊泡动力学， 视网膜双极细胞分离自OKA处理的斑马鱼，而在目标2中，我们将揭示突触 OKA处理的斑马鱼中线粒体功能障碍和带状突触处的钙信号传导。的结果 这项研究计划将使我们能够确定是否在突触囊泡的运动缺陷，突触 线粒体动力学和局部Ca2+稳态是AD未来发展的前奏。数据 从这个建议中产生的将超出我们对双极细胞的具体研究，以定义 突触丢失和功能障碍。

Project Abstract Dementias, including those associated with Alzheimer's disease (AD), are major neurodegenerative disorders that cause visual problems due to pathologic changes in the retina and optic nerve and higher cortical impairment. In AD these include changes in contrast sensitivity, visual acuities, and color vision. Despite the growing idea that the retina can be used in early diagnosis of AD, little is known about the underlying mechanism associated with AD histopathology markers and visual impairment. These mechanisms must be deciphered for the development of effective therapeutics for AD. Sensory synapses in the retina rely on the proper function of the synaptic ribbon, which is a specialized organelle anchored to the presynaptic active zone. Synaptic dysfunction (synaptopathy) is a critical common biological mechanism that links protein pathologies to AD symptoms. The long-term goal of our parent research program is to reveal the regulation of Ca2+ signaling in retinal ribbon synapses during development, normal adulthood, and disease states that affect the retina. While in the parent research program focuses on local Ca2+signaling and its interplay with the vesicle replenishment required for neurotransmitter release, the supplementary research program will apply this knowledge to AD. Our approach to both projects uses a confluence of state-of-the-art techniques, including fluorescence imaging, voltage-clamp electrophysiology, computational modeling, electron microscopy of individual physiologically identified cells, and pharmacological tools. We will use a novel and robust model for AD in adult zebrafish treated with okadaic acid (OKA) that exhibits the holistic representation of important AD hallmarks and replicates the memory deficiencies of AD. Our central hypothesis is that AD histopathology hallmarks that develop in the retina of OKA-treated zebrafish result in the onset and progression of dysfunction of the bipolar retinal ribbon synapse by altering synaptic vesicle mobility, mitochondrial function, and calcium dysregulation. Our hypothesis is supported by recent studies in which OKA treatment of zebrafish resulted in the formation of major histopathological hallmarks of AD, including amyloid beta (Aβ) protein fragments, neurofibrillary tangles (NFTs), hyperphosphorylated tau protein, and accumulation of senile plaques, leading to neurodegeneration, cognitive impairments, oxidative stress, neuroinflammation, glial cell activation, glutamate excitotoxicity, and mitochondrial dysfunction. In objective 1, we will determine the synaptic vesicle dynamics in retinal bipolar cells isolated from OKA-treated zebrafish, while in objective 2, we will reveal the synaptic mitochondrial dysfunction and calcium signaling at ribbon synapses in OKA-treated zebrafish. The results of this research program will allow us to determine whether defects in synaptic vesicle mobility, synaptic mitochondrial dynamics, and local Ca2+ homeostasis are a prelude to future development of AD. Data generated from this proposal will extends beyond our specific investigation of bipolar cells to define the role of synapse loss and dysfunction in AD.