Elucidating the roles of AMPK isoforms in Alzheimer's Disease Pathogenesis

阐明 AMPK 亚型在阿尔茨海默病发病机制中的作用

• 批准号: 9468906
• 负责人: Helena Rose Zimmermann
• 金额: $ 4.4万
• 依托单位: WAKE FOREST UNIVERSITY HEALTH SCIENCES
• 依托单位国家: 美国
• 财政年份: 2017
• 资助国家: 美国
• 起止时间: 2017-09-30 至 2019-09-29
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/9468906
• 关键词: 5' -AMP-activated protein kinase; Alzheimer' s Disease; Alzheimer' s disease model; Amyloid beta-Protein; Amyloid deposition; Behavior; Behavioral; Biochemical; Brain; Cause of Death; Cell model; Cognition Disorders; Communities; Defect; Dementia; Development; Disease; Elderly; Electrophysiology (science); Epidemic; Event; Excision; Functional disorder; Genes; Genetic; Genetic Translation; Goals; Hippocampus (Brain); Homeostasis; Human; Impairment; Intervention; Knockout Mice; Learning; Light; Long-Term Potentiation; Memory; Memory Loss; Memory impairment; Methods; Molecular; Mus; Mutant Strains Mice; Mutation; Neurodegenerative Disorders; Neurons; Pathogenesis; Pathology; Patients; Phosphotransferases; Prevention; Preventive Intervention; Prosencephalon; Protein Biosynthesis; Protein Isoforms; Protein Kinase; Proteins; Proto-Oncogene Proteins c-akt; Publications; Regulation; Repression; Research; Role; Short-Term Memory; Signal Pathway; Signal Transduction; Synaptic plasticity; Technical Expertise; Testing; Time; Transgenic Mice; Treatment Efficacy; V717F; Work; aging population; brain health; brain tissue; diagnostic biomarker; excitatory neuron; experimental study; familial Alzheimer disease; human tissue; impaired capacity; improved; morris water maze; mouse model; mutant mouse model; new therapeutic target; novel; novel diagnostics; object recognition; rapid growth; sensor; spatial memory; synaptic failure; targeted biomarker; therapeutic target

Project Summary/Abstract Alzheimer’s disease (AD) is the most common form of dementia in the elderly, and may become a new epidemic in the 21st century in accordance with the rapid growth of the aging population. There is currently no known cure or treatment to stop the progression of AD. Moreover, the basic molecular mechanisms responsible for AD remain elusive. Two key events in AD pathophysiology are impaired capacity of de novo protein synthesis (mRNA translation) and disrupted cellular energy homeostasis. AMP-activated protein kinase (AMPK) acts as a central cellular energy sensor to maintain cellular energy homeostasis. Furthermore AMPK integrates several signaling pathways (including AKT, GSK3, mTORC1, and eEF2) controlling de novo protein synthesis, dysregulation of which is implicated in cognitive syndromes associated with neurodegenerative diseases including AD. Mammalian AMPK is a heterotrimeric protein with a catalytic α subunit and regulatory β/γ subunit. The α subunit of AMPK exists in two isoforms: α1 and α2, and their roles in AD are unknown. By investigating brain tissue from post mortem human AD patients and a transgenic mouse model of AD, I have found that levels of AMPKα1 are dramatically increased while levels of AMPKα2 are decreased. The central hypothesis of the current project is that disruption of AMPK isoform homeostasis represents a key molecular mechanism of AD pathophysiology. Thus, the objective of this project is to determine whether selective AMPK isoform inhibition (and subsequent altering of AMPK isoform homeostasis) alleviates AD-associated deficits in protein synthesis and memory formation. This project will utilize a novel mouse model in which Prkaa1 and Prkaa2 (genes that encode AMPK α1 and α2 subunits, respectively) were removed in excitatory neurons in forebrains and hippocampus late in development, to generate brain- and isoform-specific conditional AMPKα1 and α2 knockout mice (AMPKα1 cKO and AMPKα2 cKO). We have further crossed the heterozygous AMPKα1/2 cKO mice [AMPKα1(+/-) and AMPKα2(+/-)] with Tg19959 AD mouse model (containing two familial AD mutations: K670N and V717F) to generate Tg19959/AMPKα1(+/-) and Tg19959/AMPKα2(+/-) double mutant mice. Using behavioral, electrophysiological, and biochemical methods, the experiments here will 1) elucidate the effects of genetic repression of AMPK isoforms on AD-associated synaptic plasticity impairments; 2) determine the effects of AMPK isoform suppression in learning and memory deficits in AD model mice; and 3) establish whether specific AMPK isoform reduction improves AD pathology, including brain amyloid deposition and de novo protein synthesis impairments. The experimental findings derived from this project will help elucidate a novel mechanism for AD pathophysiology, shedding a light on potentially new diagnostic biomarkers and therapeutic targets.

项目摘要/摘要 阿尔茨海默病(AD)是老年人中最常见的痴呆形式，并可能成为一种新的 21世纪的疫情符合老龄化人口的快速增长。目前没有 已知的治疗方法或治疗方法可以阻止AD的进展。此外，基本的分子机制 对AD的责任仍然难以捉摸。阿尔茨海默病病理生理学中的两个关键事件是新生能力受损 蛋白质合成(信使核糖核酸翻译)和细胞能量动态平衡被破坏。AMP激活的蛋白激酶 (AMPK)作为一种中枢细胞能量感受器，维持细胞能量稳态。此外，AMPK 整合了多种控制从头蛋白的信号通路(包括AKT、GSK3、mTORC1和eEF2) 合成，其调节失调与神经退行性变相关的认知综合征有关 疾病包括阿尔茨海默病。哺乳动物AMPK是一种具有催化α亚基和调控功能的异源三聚体蛋白 β/γ亚基。AMPK的α亚基以两种亚型存在：α1和α2，它们在AD中的作用尚不清楚。通过 研究死后人类AD患者的脑组织和AD转基因小鼠模型，我有 发现AMPKα1水平显著升高，而AMPKα2水平显著降低。中环 目前项目的假设是，AMPK亚型稳态的破坏代表了一个关键的分子 AD的病理生理学机制。因此，本项目的目标是确定选择性AMPK 异构体抑制(以及随后改变AMPK异构体稳态)减轻AD相关的缺陷 蛋白质的合成和记忆的形成。该项目将利用一种新的小鼠模型，在该模型中，Prkaa1和 在兴奋性神经元中，Prkaa2(分别编码AMPKα1和α2亚单位的基因)被移除 发育后期的前脑和海马体，产生脑和异构体特异的条件性AMPKα1 α2基因敲除小鼠(AMPKα1CKO和AMPKα2CKO)。我们已经进一步跨越了杂合子 采用Tg19959 AD模型的AMPKα1/2 CKO小鼠[AMPKα1(+/-)和AMPKα2(+/-)] AD突变：K670N和V717F)产生Tg19959/AMPKα1(+/-)和Tg19959/AMPKα2(+/-)双 突变的小鼠。使用行为学、电生理学和生化方法，这里的实验将1) 阐明AMPK亚型基因抑制对AD相关突触可塑性损伤的影响； 2)检测AMPK亚型抑制对AD模型小鼠学习记忆障碍的影响； 3)确定特定的AMPK亚型减少是否改善了AD的病理，包括脑淀粉样蛋白 沉积和从头合成蛋白质的损伤。从这个项目中得出的实验结果将 有助于阐明AD病理生理学的新机制，为潜在的新诊断提供线索 生物标志物和治疗靶点。