Isoform-specific roles of AMPK in synaptic failure and memory deficit in Alzheimer's Disease

项目概要/摘要 与阿尔茨海默病（AD）相关的基本分子机制仍然是一个关键的知识缺口 这阻碍了有效治疗靶点和诊断/预后生物标志物的识别。目前的 该提案将通过研究与 AMP 激活相关的信号通路的作用来解决这一差距 AD 中的蛋白激酶 (AMPK) 亚型。 AMPK 充当中央细胞能量传感器来维持能量 体内平衡。此外，AMPK 是整合 de novo 蛋白多种信号通路的纽带 合成（mRNA 翻译）。重要的是，能量稳态的破坏和从头的损伤 蛋白质合成与神经退行性疾病相关的认知综合征有关，包括 公元。 AMPK 的激酶催化亚基在大脑中以两种亚型存在：α1 和 α2，及其在突触中的作用 可塑性和记忆性是未知的。我们生成了大脑和异构体特异性的条件 AMPKα1 和 α2 敲除小鼠（AMPKα1 cKO 和 AMPKα2 cKO），并进行行为学、电生理学、成像和 生化测试来表征亚型特异性表型。在我们的初步数据的推动下，我们的中央 假设 AMPK 亚型稳态的破坏代表了潜在的关键分子机制 AD 相关的突触可塑性损伤和记忆缺陷。制定了三个具体目标 检验假设。目标 1 旨在确定 AMPK 在海马突触可塑性中的异构体特异性作用 和记忆的形成。目标 2 旨在确定突触衰竭的 AMPK 亚型特异性调节 Tg19959 AD 小鼠模型中的记忆障碍。目标 3 旨在阐明 AMPK 亚型特异性 对 Tg19959 AD 小鼠模型中从头蛋白质合成和脑 Aβ 病理学的影响。项目 提出使用神经科学和 AD 领域多种最先进的方法（包括小鼠）进行深入分析 遗传学、突触电生理学、共焦成像和行为测试。此外，新颖的方法 结合质谱/蛋白质组学方法测量从头蛋白质合成将应用于 揭示 AD 大脑中蛋白质的身份，这些蛋白质的合成因异常信号传导而失调 破坏 AMPK 同工型稳态。这种多学科方法将使我们能够确定详细的 AD 发病机制中与异常 AMPK 信号传导相关的细胞/分子机制，提供 对 AD 和其他痴呆症综合征的新治疗靶点和诊断生物标志物的见解。

Project Summary/Abstract The basic molecular mechanisms associated with Alzheimer’s disease (AD) remain a critical knowledge gap that prevents identification of effective therapeutic targets and diagnostic/prognostic biomarkers. The current proposal will address this gap by studying the role of signaling pathways associated with AMP-activated protein kinase (AMPK) isoforms in AD. AMPK functions as a central cellular energy sensor to maintain energy homeostasis. Moreover, AMPK is a nexus to incorporate multiple signaling pathways for de novo protein synthesis (mRNA translation). Importantly, both disruptions in energy homeostasis and impairments in de novo protein synthesis are implicated in cognitive syndromes associated with neurodegenerative diseases, including AD. The kinase catalytic subunit of AMPK exists in two isoforms in brain: α1 and α2, and their roles in synaptic plasticity and memory are unknown. We generated brain- and isoform-specific conditional AMPKα1 and α2 knockout mice (AMPKα1 cKO and AMPKα2 cKO), and performed behavioral, electrophysiology, imaging, and biochemical tests to characterize isoform-specific phenotypes. Driven by our preliminary data, our central hypothesis is that disruption of AMPK isoform homeostasis represents a key molecular mechanism underlying AD-associated impairments of synaptic plasticity and memory defects. Three specific aims are formulated to test the hypothesis. Aim 1 seeks to identify isoform-specific roles of AMPK in hippocampal synaptic plasticity and memory formation. Aim 2 is designed to determine AMPK isoform-specific regulation of synaptic failure and memory impairment in Tg19959 AD mouse model. Aim 3 is designed to elucidate AMPK isoform-specific effects on de novo protein synthesis and brain Aβ pathology in Tg19959 AD mouse model. The project proposes in-depth analyses using multiple state-of-art methods in neuroscience and AD, including mouse genetics, synaptic electrophysiology, confocal imaging, and behavioral tests. Moreover, novel methods to measure de novo protein synthesis combined with mass spectrometry/proteomics approach will be applied to reveal identities of proteins in AD brains whose synthesis is dysregulated because of abnormal signaling due to disruption of AMPK isoform homeostasis. This multidisciplinary approach will enable us to identify detailed cellular/molecular mechanisms associated with aberrant AMPK signaling in AD pathogenesis, providing insights into novel therapeutic targets and diagnostic biomarkers for AD and other dementia syndromes.