Functional Effects of PDE11A Alzheimer's-Associated Variants

PDE11A 阿尔茨海默病相关变体的功能影响

• 批准号: 10494545
• 负责人: Michy Patrice Kelly
• 金额: $ 38.62万
• 依托单位: UNIVERSITY OF MARYLAND BALTIMORE
• 依托单位国家: 美国
• 财政年份: 2019
• 资助国家: 美国
• 起止时间: 2019-02-15 至 2023-11-30
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/10494545
• 关键词: Age; Age-associated memory impairment; Aging; Alzheimer' s Disease; Alzheimer' s disease related dementia; Axon; Behavioral; Biochemical; Brain; Cell Line; Coupled; Coupling; Development; Early Onset Alzheimer Disease; Elderly; Enzymes; Episodic memory; Functional disorder; Goals; Hippocampal Formation; Hippocampus (Brain); Human; Impaired cognition; Impairment; In Vitro; Induced Mutation; Knockout Mice; Mus; Mutation; Mutation Analysis; Neurosciences; Phosphorylation; Physiological; Presynaptic Terminals; Process; Proteins; Recombinants; Recording of previous events; Rodent; Signal Transduction; Testing; Variant; age related; aged; demented; dementia risk; gain of function; genetic manipulation; in vitro Assay; in vivo; innovation; insight; interest; loss of function; mutant; non-demented; normal aging; parent grant; phosphodiesterase 11a; protein expression; tau Proteins; tau-1

PROJECT SUMMARY: Functional Effects of PDE11A Alzheimer’s Disease (AD)-Associated Variants This parent grant explores how age-related increases in expression and ectopic localization of the enzyme Phosphodiesterase 11A (PDE11A) drive age-related cognitive decline (ARCD). PDE11A is of particular interest in the context of aging and AD because its expression in brain is enriched in the hippocampal formation—a region that is critical for episodic memory and is severely impaired in AD. We find PDE11A expression increases with age in the rodent and human hippocampus and is further elevated in hippocampus of demented vs. non-demented aged humans with a history of TBI. We have established that these age-related increases in PDE11A are ectopically enriched in hippocampal “ghost axons”—that is, axonal terminals that are so densely packed with PDE11A protein that other axonal proteins are occluded. Through mutational analyses, we have identified intramolecular signals responsible for these age-related increases in PDE11A expression and its ectopic localization and have shown that Pde11a knockout mice are protected against ARCD. Given that advanced age is the strongest risk factor for dementia, coupled with the fact that these PDE11A “ghost axons” are particularly reminiscent of tau proteinopathies that are associated with ADRDs, it is highly interesting that 2 rare PDE11A variants (i.e., R202H and L756Q) have recently been associated with early-onset AD. The impact of these mutations on PDE11A function were not measured directly; however, expression of the mutants increased phosphorylation of recombinant tau in an in vitro assay. This PDE11A mutation-induced increase in p-tau is consistent with the pathophysiology observed in ADRD brains; however, it suggests a PDE11A loss-of- function that stands in direct contrast to the PDE11A gain-of-function that we observe with normal aging. As such, we test the overarching hypothesis that AD-related PDE11A mutations alter catalytic activity and/or subcellular compartmentalization of PDE11A in a manner that fundamentally differs from aging itself, thereby producing biochemical and behavioral deficits worse than those seen with normal aging. Across the 2 aims, we take an integrative approach by coupling in vivo and in vitro genetic manipulations with behavioral, physiological, and biochemical endpoints. In Specific Aim 1, we determine how the AD-related PDE11A variants alter protein expression, catalytic activity, subcellular compartmentalization, phosphorylation, and downstream signaling of PDE11A in a hippocampal cell line that endogenously expresses tau and recapitulates PDE11A age-related proteinopathies. In Specific Aim 2, we determine if elevated expression of these PDE11A AD-associated variants in mouse hippocampus produces more widespread cognitive decline than elevated expression of wild-type PDE11A.These innovative studies will provide much needed insight into the functional consequences of these AD-related mutations and are consistent with the Division of Neuroscience’s goal to understand how the processes of ARCD intersect with the development of AD.

项目摘要：PDE11A阿尔茨海默氏病（AD）相关变体的功能效应 该父母赠款探讨了与年龄相关的酶表达和异位定位的增加 磷酸化酶11A（PDE11A）驱动与年龄相关的认知下降（ARCD）。 PDE11A特别感兴趣 在衰老和AD的背景下，因为它在大脑中的表达富集在海马形成中，A 对于情节记忆至关重要的区域，并且在AD中严重受损。我们发现pde11a表达式 随着啮齿动物和人类海马的年龄的增加而增加，并在痴呆的海马中进一步升高 具有TBI史的非痴呆的老年人。我们已经确定这些与年龄有关的增加 PDE11a在海马“幽灵轴突”上富含PDE11a，即轴突终端非常密集 用PDE11A蛋白包装，其他轴突蛋白被阻塞。通过突变分析，我们有 确定了负责这些年龄相关的分子内信号PDE11a表达及其 异位定位，并表明PDE11A敲除小鼠受到ARCD的保护。鉴于 高龄是痴呆症的强大危险因素，再加上这些PDE11a“鬼轴突” 特别让人联想到与ADRD相关的tau蛋白质病，非常有趣的是2 罕见的PDE11A变体（即R202H和L756Q）最近与早发广告有关。影响 这些关于PDE11A功能的突变未直接测量；但是，突变体的表达 在体外测定中重组TAU的磷酸化增加。这种PDE11A突变引起的增加 P-TAU与在Adrd大脑中观察到的病理生理学一致。但是，它表明PDE11A - 与正常衰老观察到的PDE11A功能获得的功能直接形成鲜明对比。作为 这样，我们检验了与AD相关的PDE11A突变改变催化活性和/或的总体假设 PDE11a的亚细胞分室化的方式与衰老本身有所不同， 从而产生生化和行为的定义比正常衰老的人更糟糕。 在两个目标中，我们通过在体内耦合和体外遗传操纵与 行为，物理和生化终点。在特定目标1中，我们确定与广告相关的方式 PDE11A变体改变了蛋白质表达，催化活性，亚细胞隔室化，磷酸化，磷酸化， PDE11a的下游信号在海马细胞系中，内源表达tau和 概括了PDE11A年龄相关的蛋白质。在特定目标2中，我们确定是否升高 这些PDE11A与AD相关的鼠标海马变体产生更多的宽度认知下降 比野生型PDE11a的表达升高。这些创新的研究将为您提供急需的洞察力 这些与广告相关的突变的功能后果，与分裂一致 神经科学的目标是了解ARCD的过程如何与AD的发展相交。