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Dysregulation of Protein Prenylation in the Pathogenesis of Alzheimer's Disease

阿尔茨海默病发病机制中蛋白质异戊二烯化的失调

基本信息

批准号：
9376111
负责人：
MARK D DISTEFANO
金额：
$ 187.59万
依托单位：
UNIVERSITY OF MINNESOTA
依托单位国家：
美国
项目类别：
财政年份：
2017
资助国家：
美国
起止时间：
2017-08-01 至 2022-08-31
项目状态：
已结题

来源：
https://reporter.nih.gov/project-details/9376111
关键词：
Adverse effects Alzheimer&apos s Disease Alzheimer&apos s disease model Amyloid beta-Protein Attenuated Behavioral Biochemical Brain Brain Diseases Brain Pathology C-terminal Cell membrane Cell physiology Cerebrum Characteristics Cognition Cognitive Cognitive deficits Data Dementia Development Dimethylallyltranstransferase Disease Elderly Electrophysiology (science)Embryo Event Functional disorder Genetic Genotype Goals HRAS gene Heterotrimeric GTP-Binding Proteins Human Impaired cognition In Vitro Individual Lead Letters Link Lipids LoxP-flanked allele Mediating Membrane Modification Monomeric GTP-Binding Proteins Mus Neurodegenerative Disorders Neurofibrillary Tangles Neurons Pathogenesis Pathogenicity Pathology Pathway interactions Patients Pharmacology Play Positioning Attribute Post-Translational Protein Processing Process Production Protein Dynamics Protein Farnesylation Protein Geranylgeranylation Protein Isoprenylation Proteins Reaction Research Role Senile Plaques Signal Pathway Synapses Synaptic plasticity Testing Up-Regulation abeta accumulation analog base behavior test beta amyloid pathology brain tissue cognitive development cognitive function design effective intervention experience experimental study farnesyl pyrophosphate genetic approach geranylgeranyl pyrophosphate human tissue hyperphosphorylated tau improved innovation isoprenoid mild cognitive impairment mouse Cre recombinase mouse model neuroinflammation neuropathology neurophysiology novel therapeutic intervention prenyl prenylation promoter protein B protein protein interaction synaptic function tau Proteins

项目摘要

PROJECT SUMMARY The pathogenic mechanisms underlying the development of Alzheimer’s disease (AD) remain elusive. Intriguingly, emerging evidence indicates that a posttranslational lipid modification of proteins, known as prenylation, may play an important role in the pathogenesis of AD. Prenylation reactions are catalyzed by prenyltransferases that attach isoprenoids, either farnesyl or geranylgeranyl pyrophosphate, to proteins with a characteristic C-terminal motif. The lipid prenyl group facilitates anchoring of proteins in cell membranes and mediates protein-protein interactions. Prenylated proteins, including small GTPases comprising the Ras superfamily along with heterotrimeric G-proteins, are involved in regulating diverse cellular processes. In AD, the role of protein prenylation is underexplored. Several studies show that modulation of protein prenylation influences amyloid-β (Aβ) and tau levels, neuroinflammation, synaptic plasticity, and cognitive function. However, most of those studies were conducted in vitro and by pharmacological inhibition of isoprenoid production rather than direct modulation of protein prenylation. Using a direct genetic approach, our recent studies show that the two protein prenylation pathways play distinct neurophysiological roles. Reducing protein farnesylation rescues cognitive function as well as attenuates Aβ pathology whereas reducing protein geranylgeranylation results in adverse effects on synaptic function. In addition, our preliminary studies show that the level of membrane-associated H-Ras, an exclusively farnesylated protein, is significantly increased in the brain of patients with mild cognitive impairment (MCI) and AD compared to individuals with normal cognitive function; and the level of farnesylated H-Ras correlates significantly with the activation of ERK, a major downstream effector of H-Ras. Thus, we hypothesize that upregulation of protein farnesylation is an early event with primary importance in the pathogenic cascade of AD and activation of downstream signaling pathways contributes to the development of cognitive impairment and neuropathology. This central hypothesis will be tested rigorously by three specific aims using a combination of innovative genetic, behavioral, electrophysiological, and prenylomic approaches. Aim 1 is to test the hypothesis that neuron-specific deletion of protein farnesylation mitigates cognitive deficit, synaptic dysfunction, and pathology in a mouse model of AD. Aim 2 is to test the hypothesis that deletion of H-Ras improves whereas over-activation of H-Ras exacerbates cognitive/synaptic deficit and pathology in AD mice. Aim 3 is to elucidate the relationship between AD pathology and the levels of prenylated proteins in mouse models and human brain tissues. The overall goal of the project is to unravel the underexplored but potentially critical pathogenic mechanisms of AD involving protein prenylation and related pathways. Clarifying the linkage between prenylation and AD could be a transformative discovery and lead to the development of new therapeutic strategies.

项目概要阿尔茨海默病（AD）发展的致病机制仍然难以捉摸。有趣的是，新出现的证据表明蛋白质的翻译后脂质修饰，称为异戊二烯化可能在 AD 的发病机制中发挥重要作用。异戊二烯化反应由以下物质催化异戊二烯转移酶将类异戊二烯（法呢基或香叶基香叶基焦磷酸）附着到具有特征性 C 末端基序。脂质异戊二烯基团有利于蛋白质在细胞膜上的锚定，介导蛋白质-蛋白质相互作用。异戊二烯化蛋白质，包括包含 Ras 的小 GTP 酶超家族与异三聚体 G 蛋白一起参与调节不同的细胞过程。在公元，蛋白质异戊二烯化的作用尚未得到充分研究。多项研究表明蛋白质异戊二烯化的调节影响淀粉样蛋白-β (Aβ) 和 tau 蛋白水平、神经炎症、突触可塑性和认知功能。然而，大多数这些研究是在体外通过类异戊二烯的药理抑制进行的生产而不是直接调节蛋白质异戊二烯化。使用直接遗传方法，我们最近研究表明，两种蛋白质异戊二烯化途径发挥着不同的神经生理学作用。减少蛋白质法尼基化可挽救认知功能并减弱 Aβ 病理，同时减少蛋白质香叶基香叶基化会对突触功能产生不利影响。此外，我们的初步研究表明与膜相关的 H-Ras（一种专门的法尼基化蛋白）的水平在轻度认知障碍 (MCI) 和 AD 患者的大脑与正常人的大脑相比认知功能；法尼基化 H-Ras 的水平与 ERK 的激活显着相关，ERK 是一种 H-Ras 的主要下游效应子。因此，我们假设蛋白质法尼基化的上调是在 AD 致病级联反应和下游信号激活中具有首要重要性的早期事件途径有助于认知障碍和神经病理学的发展。这个中心假设将通过三个具体目标的严格测试，结合创新的遗传、行为、电生理学和异戊二烯组学方法。目标 1 是检验神经元特异性缺失的假设蛋白质法尼基化可减轻小鼠模型中的认知缺陷、突触功能障碍和病理学广告。目标 2 是检验以下假设：H-Ras 的缺失会改善而 H-Ras 的过度激活加剧 AD 小鼠的认知/突触缺陷和病理。目标3是阐明之间的关系 AD 病理学以及小鼠模型和人脑组织中异戊二烯化蛋白的水平。总体目标该项目的目的是揭示 AD 尚未充分探索但潜在关键的致病机制，涉及蛋白质异戊二烯化和相关途径。澄清异戊二烯化和 AD 之间的联系可能是变革性发现并导致新治疗策略的开发。