The Role of cAMP/PKA Dysregulation in Aging and the Initial Stages of Alzheimer'sDisease

项目摘要/摘要 迟发性阿尔茨海默病(LOAD)是一种日益严重的公共健康危机，已经让我们的国家付出了代价 每年数十亿美元。目前还没有治疗方法来减缓负荷的进展。年龄是最重要的 负荷的最大风险因素。这种疾病有两个关键的病理特征，即淀粉样β斑块。 以及由过度磷酸化的tau组成的神经纤维缠结。本项目重点研究 衰老导致负荷病理早期阶段的分子机制，特别是tau 磷酸化。为了更好地理解这些机制，这个项目利用了两个动物模型， 老化的老鼠和猕猴。猕猴在以下方面与人类老化的皮质非常接近 电路和负载病理学；然而，它们在技术上具有挑战性。另一方面，老鼠则不会 出现斑块或缠结，但确实表现出与年龄相关的认知能力下降和初步证据 提示它们存在tau磷酸化的早期阶段。此外，啮齿动物提供了广泛的 分子工具，以研究确切的机制，通过与年龄相关的变化有助于AD的病理。 奈恩和阿恩斯滕实验室之前的研究表明，cAMP/PKA信号随着年龄的增长而增加 在这两个模型中，这与tau磷酸化和认知功能下降相关。因此，拟议的 Project研究了cAMP/PKA信号随年龄变化的分子驱动因素。目标1a调查该角色 与年龄相关的神经炎性信号的增加通过去除 刹车，通过磷酸二酯酶的失调。目标1b侧重于以下方面的增加 CAMP/PKA信号通过磷酸化产生有害的正反馈信号级联反应 兰诺定受体。我计划研究Ryanodine受体的PKA磷酸化如何增加 Ryanodine受体释放钙并进一步推动cAMP的产生。这两个子目标都检查 异常信号对tau蛋白激酶A磷酸化的影响及其对认知功能减退的影响。目标2 通过开发一种新的质谱学方法来扩大这些研究的范围 分析磷酸化的tau。这种新的方法能够监测整个蛋白质的磷酸化位点作为 以及条件之间的激酶基序的丰富；因此，使我们能够更全面地了解 Tau修饰，以及它们下面的信号通路。将这种新方法与传统方法相结合 利用磷仿生对tau蛋白行为的生化分析，目标2将能够调查 与年龄相关的cAMP/PKA变化在Load tau病理中的重要作用。穿过 这个项目的目标是在质谱学、生物统计学和皮质学方面接受广泛的培训。 神经生物学，所有这些都将为我在翻译神经生物学研究领域的理想职业做准备。总的来说， 这个项目研究了新的分子靶点，代表了治疗黑色素瘤的新靶点。 装填。

Project Summary/Abstract Late-onset Alzheimer’s disease (LOAD) is a growing public health crisis that already costs our country billions of dollars each year. Currently there are no treatments to slow the progression of LOAD. Age is the largest risk factor for LOAD. There are two key pathological hallmarks of the disease, amyloid beta plaques and neurofibrillary tangles composed of hyperphosphorylated tau. This project focuses on studying the molecular mechanisms by which aging contributes to initial stages of LOAD pathology, particularly tau phosphorylation. To better understand these mechanisms, this project takes advantage of two animal models, aged rats and macaques. Macaques represent a close approximation of the human aging cortex in regards to circuitry and LOAD pathology; however, they are technically challenging. Rats on the other hand do not develop plaques or tangles but do demonstrate age-related cognitive decline and preliminary evidence suggests they present with early stages of tau phosphorylation. Furthermore, rodents provide a breadth of molecular tools to investigate the exact mechanisms by which age-related changes contribute to AD pathology. Previous work from the Nairn and Arnsten labs has demonstrated an increase in cAMP/PKA signaling with age in both of these models, which correlates with tau phosphorylation and cognitive decline. Thus, the proposed project examines the molecular drivers of aberrant cAMP/PKA signaling with age. Aim 1a investigates the role of age-related increases in neuroinflammatory signaling in driving excess cAMP production by removing the brakes, through dysregulation of phosphodiesterases. Aim 1b focuses on the ways in which increases in cAMP/PKA signaling generate a deleterious positive-feedback signaling cascade through phosphorylation of the ryanodine receptor. I plan to investigate how PKA phosphorylation of the ryanodine receptor can increase calcium release from ryanodine receptors and further drive cAMP production. Both of these sub-aims examine the effects of aberrant signaling on PKA phosphorylation of tau and their impact on cognitive decline. Aim 2 expands the scope of these studies through the development of a novel mass spectrometry approach to analyze phosphorylated tau. This novel approach is able to monitor phospho-sites throughout the protein as well as the enrichment of kinase motifs between conditions; thus, enabling a more complete understanding of tau modifications, and the signaling pathways underlying them. Combining this new approach with traditional biochemical assays of tau protein behavior with the use of phosphomimetics, Aim 2 will be able to investigate the important steps by which age-related changes in cAMP/PKA contribute to LOAD tau pathology. Through the aims of this project I will receive extensive training in mass spectrometry, biostatistics, and cortical neurobiology, all of which will prepare me for my desired career in translational neurobiology research. Overall, this project investigates novel molecular targets that represent new therapeutic targets for the treatment of LOAD.