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、视神经和大脑皮层的病理改变而引起的视觉问题 减损。在AD中，这些包括对比敏感度、视觉敏锐度和色觉的变化。尽管 越来越多的人认为视网膜可以用于AD的早期诊断，但对其潜在的机制知之甚少 与AD组织病理学标志物和视力损害相关的机制。这些机制必须是 为开发治疗阿尔茨海默病的有效疗法破译。视网膜中的感觉突触依赖于 突触带的正常功能，突触带是固定在突触前活动的特殊细胞器 区域。突触功能障碍(突触障碍)是连接蛋白质的一种关键的常见生物学机制 阿尔茨海默病症状的病理学特征。我们家长研究计划的长期目标是揭示 发育、正常成年期和影响疾病状态的视网膜带突触中的CA2信号 视网膜。而在父母的研究计划中，重点是局部钙信号及其与细胞的相互作用 神经递质释放所需的囊泡补充，补充研究计划将适用 这一知识传给了公元。我们对这两个项目的方法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，电子显微镜 单个生理识别的细胞和药理工具。我们将使用一种新颖而健壮的模型来 用冈田酸(OKA)处理的成年斑马鱼的AD表现为重要AD的整体表现 标记和复制AD的记忆缺陷。我们的中心假设是AD组织病理学 OKA处理的斑马鱼视网膜中形成的特征导致功能障碍的发生和发展 通过改变突触的囊泡运动、线粒体功能和钙离子改变双极视网膜带突触 监管失调。我们的假设得到了最近的研究的支持，在这些研究中，OKA处理斑马鱼导致了 阿尔茨海默病主要组织病理学特征的形成，包括淀粉样β蛋白(Aβ)片段， 神经原纤维缠结(NFTs)、过度磷酸化的tau蛋白和老年斑的堆积，导致 神经变性、认知障碍、氧化应激、神经炎症、神经胶质细胞激活、谷氨酸 兴奋性毒性和线粒体功能障碍。在目标1中，我们将确定突触小泡的动力学 从OKA处理的斑马鱼中分离出视网膜双极细胞，而在目标2中，我们将揭示突触 OKA处理的斑马鱼线粒体功能障碍和突触带状钙信号。结果是 这项研究计划将使我们能够确定突触小泡流动性缺陷，突触 线粒体动力学和局部钙稳态是AD未来发展的前奏。数据 从这项提案中产生的结果将超出我们对双极细胞的具体调查，以定义 阿尔茨海默病的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.