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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.

项目总结