Elucidating the contribution of amyloidogenic APP processing to AD-relevant impaired synaptic protein turnover

阐明淀粉样蛋白生成 APP 加工对 AD 相关突触蛋白周转受损的影响

基本信息

批准号：
10538032
负责人：
Nalini Rao
金额：
$ 4.68万
依托单位：
NORTHWESTERN UNIVERSITY AT CHICAGO
依托单位国家：
美国
项目类别：
财政年份：
2023
资助国家：
美国
起止时间：
2023-01-01 至 2024-12-31
项目状态：
已结题

来源：
https://reporter.nih.gov/project-details/10538032
关键词：
Address Affect Alzheimer&apos s Disease Alzheimer&apos s disease brain Alzheimer&apos s disease pathology Alzheimer&apos s disease patient Amyloid beta-42 Amyloid beta-Protein Amyloid beta-Protein Precursor Animals Antibodies Antiepileptic Agents Axon Biological Assay Brain Critical Pathways Dementia Disease Endocytosis Endosomes Etiology Event Functional disorder Goals Human Impairment In Vitro Knock-in Knock-in Mouse Label Lead Levetiracetam Mass Spectrum Analysis Measures Metabolic Microfluidic Microchips Modeling Molecular Mus Mutation Neurodegenerative Disorders Neurofibrillary Tangles Neurons Pathogenicity Pathologic Pathology Pathway interactions Peptides Periodicity Persons Phenotype Physiologic pulse Play Pre-Clinical Model Presynaptic Terminals Prevalence Process Production Proteins Proteome Proteomics Reporter Research Role Site Synapses Synaptic Vesicles System Techniques Testing Therapeutic Tissues Ubiquitin Ubiquitination Work amyloid pathology amyloid precursor protein processing base biochemical tools clinically relevant diagnostic tool hyperphosphorylated tau in vitro Model in vivo mouse model multicatalytic endopeptidase complex neuronal cell body novel overexpression prevent protein aggregation protein degradation protein misfolding protein transport proteostasis small molecule stable isotope tau Proteins tool uptake vesicle transport

项目摘要

Project Summary Alzheimer’s disease (AD) is a debilitating neurodegenerative disease and the most prevalent form of dementia. AD is pathologically characterized by two misfolded and aggregated proteins: amyloid-beta peptides (Aβ42) and hyperphosphorylated tau. Although Aβ42 accumulation, produced amyloidogenic processing of the amyloid precursor protein (APP), is one of the earliest pathological events, the initial trigger in proteostasis imbalance remains unknown. To investigate proteostasis impairments in AD, our research utilizes metabolic pulse-chase (pc) labeling with stable isotopes in combination with quantitative mass spectrometry (MS) based proteomic analysis. Using this strategy with the recently developed APP knock-in (App KI) mouse models of amyloid pathology, we discovered that axon terminals are selective sites of impaired protein degradation, specifically synaptic vesicle (SV) and SV-associated proteins. This alteration occurred before plaque pathology or elevated Aβ42 levels. This is important as it suggests we have identified the earliest synaptic impairment in protein turnover that occurs before amyloid pathology. Additionally, I recently discovered that targeting SVs with small molecule antiepileptic drug levetiracetam in App KI mice mitigated AD pathology by decreasing Aβ42 accumulation via alteration of amyloidogenic processing of APP. The goal of my proposed project is to uncover the mechanism for impaired synaptic proteostasis in models of preclinical amyloid pathology that may underlie the initial trigger in the cascade of pathologies seen in AD. One mechanism for turnover at the presynapse is thought to rely on the ubiquitin-proteasome system (UPS) marking proteins for transport out of the axon terminal to the soma for degradation. The central hypothesis of my proposal is that amyloidogenic processing of APP leads to a deficit to this key process resulting in an impairment in axon terminal protein turnover. To address if disrupting this process impairs axon terminal proteostasis, I propose the following aims. First, I will investigate in vivo if the UPS is disrupted in App KI brains using previously pc-ed tissue and advanced MS techniques for isolation and quantification of ubiquitinated proteins. Second, I will determine if disruptions in SV transport result from amyloidogenic processing of APP and if this leads to mislocalization of APP in vitro and finally will confirm these findings in human neurons derived from AD patients. Taken all together, this proposed project will determine the initial mechanisms of AD-relevant protein degradation impairments, crucial to determining the cause of protein accumulation in AD which currently remains unknown.

项目概要阿尔茨海默病 (AD) 是一种使人衰弱的神经退行性疾病，也是最常见的形式 AD 的病理特征是两种错误折叠和聚集的蛋白质：淀粉样β肽（Aβ42）和过度磷酸化的tau蛋白虽然Aβ42积累，淀粉样前体蛋白 (APP) 产生的淀粉样变性加工是最早的加工方法之一病理事件中，蛋白质稳态失衡的最初触发因素仍然未知。 AD 中的蛋白质稳态损伤，我们的研究利用代谢脉冲追踪 (pc) 标记稳定同位素与基于蛋白质组学的定量质谱 (MS) 相结合使用该策略与最近开发的 APP 敲入（App KI）小鼠模型进行分析。淀粉样蛋白病理学，我们发现轴突末端是受损蛋白质的选择性位点降解，特别是突触小泡 (SV) 和 SV 相关蛋白。发生在斑块病理或 Aβ42 水平升高之前，这很重要，因为它表明我们。已经确定了蛋白质周转中最早的突触损伤发生在淀粉样蛋白之前此外，我最近发现用小分子抗癫痫药来靶向 SV。 App KI 小鼠中的药物左乙拉西坦通过减少 Aβ42 积累来减轻 AD 病理 APP 淀粉样变过程的改变我提出的项目的目标是揭示临床前淀粉样蛋白病理模型中突触蛋白稳态受损的机制可能是 AD 中所见的一系列病理的最初触发因素的一种机制。突触前的蛋白质被认为依赖于泛素蛋白酶体系统 (UPS) 标记蛋白质从轴突末端运输到体体进行降解我的中心假设建议认为 APP 的淀粉样蛋白形成过程会导致这一关键过程的缺陷轴突末端蛋白质周转受损，以解决扰乱此过程是否会损害的问题。对于轴突末端蛋白质稳态，我提出以下目标：首先，我将研究体内的 UPS。使用先前的 PC 编辑组织和先进的 MS 技术在 App KI 大脑中进行破坏其次，我将确定 SV 是否受到破坏。 APP 淀粉样蛋白形成过程的运输结果，以及这是否导致 APP 错误定位最终将在来自 AD 患者的人类神经元中证实这些发现。总之，这个拟议的项目将确定 AD 相关蛋白的初始机制降解损伤，对于确定 AD 中蛋白质积累的原因至关重要目前仍未知。