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

项目总结/摘要 晚发性阿尔茨海默病（LOAD）是一个日益严重的公共卫生危机，已经使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LOAD的进展。年龄是 最大的风险因素是负载。这种疾病有两个关键的病理学特征，淀粉样β斑块 和由过度磷酸化的tau组成的神经元缠结。该项目的重点是研究 衰老导致LOAD病理学初始阶段的分子机制，特别是tau蛋白 磷酸化为了更好地理解这些机制，该项目利用了两种动物模型， 老年大鼠和猕猴。猕猴代表了人类衰老皮层的一个密切近似， 电路和负载病理;然而，它们在技术上具有挑战性。另一方面，老鼠不 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， 表明它们存在于tau蛋白磷酸化的早期阶段。此外，啮齿动物提供了一个广泛的 分子工具来研究与年龄相关的变化导致AD病理学的确切机制。 Nairn和Arnsten实验室先前的工作已经证明了cAMP/PKA信号随着年龄的增长而增加 在这两种模型中，这与tau蛋白磷酸化和认知能力下降有关。因此，拟议的 该项目研究了cAMP/PKA信号传导随年龄变化的分子驱动因素。目标1a研究了角色 年龄相关的神经炎性信号增加，通过去除 刹车，通过磷酸二酯酶失调。目标1b侧重于如何增加 cAMP/PKA信号通过磷酸化产生有害的正反馈信号级联反应 Ryanodine受体。我计划研究ryanodine受体的PKA磷酸化是如何增加 钙从兰尼碱受体释放并进一步驱动cAMP产生。这两个子目标都检查 异常信号对tau蛋白PKA磷酸化的影响及其对认知能力下降的影响。目的2 通过开发一种新的质谱方法扩大了这些研究的范围， 分析磷酸化的tau。这种新方法能够监测整个蛋白质的磷酸化位点， 以及条件之间激酶基序的富集;因此，能够更完整地理解 tau蛋白修饰以及它们背后的信号通路。将这种新方法与传统方法相结合 使用磷酸模拟物进行tau蛋白行为的生化测定，Aim 2将能够研究 cAMP/PKA的年龄相关变化促成LOAD tau病理学的重要步骤。通过 这个项目的目的，我将接受广泛的培训，在质谱，生物统计学，和皮质 神经生物学，所有这些都将为我在转化神经生物学研究中的理想职业做好准备。总体而言， 该项目研究了代表新的治疗靶点的新分子靶点， 即可.

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.