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P2‐217: INTEGRATED PROTEOMICS AND PHOSPHOPROTEOMICS REVEAL NETWORKS LINKED TO ALZHEIMER'S DISEASE RISK
Author(s) -
Ping Lingyan,
Duong Duc,
Dammer Eric B.,
Gearing Marla,
Lah James J.,
Levey Allan I.,
Seyfried Nicholas T.
Publication year - 2018
Publication title -
alzheimer's and dementia
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 6.713
H-Index - 118
eISSN - 1552-5279
pISSN - 1552-5260
DOI - 10.1016/j.jalz.2018.06.905
Subject(s) - proteome , tandem mass tag , proteomics , disease , phosphoproteomics , isobaric labeling , neuroscience , pathogenesis , alzheimer's disease , tandem mass spectrometry , quantitative proteomics , computational biology , pathology , biology , chemistry , bioinformatics , medicine , biochemistry , phosphorylation , mass spectrometry , protein phosphorylation , gene , protein kinase a , chromatography
Background:Amyloid-beta (Ab) deposition in the brain is thought to be a central force driving Alzheimer’s Disease (AD) pathogenesis, yet humans remain cognitively normal for many years despite accumulating aggregates of Ab plaques and tau neurofibrillary tangles. Currently our understanding of the molecular mechanisms that underlie the transition from the asymptomatic to symptomatic phase of Alzheimer’s disease (AD) is limited. Here we report a large-scale integrated network analysis of the proteome and phosphoproteome from human postmortem brain to identify pathways relevant to both clinical and neuropathological phenotypes of AD. Methods: Using quantitative liquid chromatography coupled to tandem mass spectrometry (LC-MS/MS) we comparatively analyzed the total brain proteomes of 27 post-mortem frontal cortex samples (Brodmann Area 9) representing cognitively normal individuals without AD pathology (n1⁄410), cognitively normal asymptomatic individuals (AsymAD; n1⁄49) and cognitively impaired individuals with AD pathology (n1⁄48). Tau and Ab pathological burden was scored mild to moderate in AsymAD and severe in AD cases. Using isobaric tandem-mass tags (TMT) following offline fractionation a total of 156,425 unique peptides mapping to 11,060 proteins were identified and quantified across all 27 individual cases. Affinity enrichment of phosphopeptides using immobilized metal affinity chromatography (IMAC) was employed to enrich and quantify w25,000 phosphopeptide signatures across these same cases. Co-expression network analysis resolved functional classes of protein and phosphoproteins linked to cell-types and signaling pathways. Results: Network analysis revealed 44 modules of co-expressed proteins and phosphoproteins, 20 of which correlated with, cell-type, cognitive decline and/or AD neuropathology. Phosphopeptides on tau clearly distinguished AD from control cases with specific changes in additional signaling pathways in the phosphoproteome observed in asymptomatic stages of disease. Conclusions:This integrated comprehensive analysis of the proteome and phosphoprotoeme reveals disease-specific signaling pathways associated with clinical and pathological AD phenotypes.