Cerebrospinal fluid proteomic associations of APOE genotypes reveal distinct protective and risk mechanisms for Alzheimer's disease

Eleonora M. Vromen, Senne B. Lageman*, Johan Gobom, Rik van der Kant, Valerija Dobricic, Lars Bertram, Johannes Streffer, Simon Lovestone, Stephanie J.B. Vos, Mikel Tainta, Yvonne Freund-Levi, Lutz Frölich, Julius Popp, Gwendoline Peyratout, Magda Tsolaki, Frans Verhey, Rik Vandenberghe, Jolien Schaeverbeke, Kaj Blennow, Sven J. van der LeePhilip Scheltens, Yolande A.L. Pijnenburg, Wiesje M. van der Flier, Charlotte E. Teunissen, Henrik Zetterberg, Pieter Jelle Visser, Betty Tijms

*Corresponding author for this work
    1 Citation (Scopus)

    Abstract

    BACKGROUND: The apolipoprotein E (APOE) gene includes the strongest protective (ε2) and risk (ε4) variants for sporadic Alzheimer's disease (AD), but underlying mechanisms remain unclear. We studied APOE genotype effects on the cerebrospinal fluid (CSF) proteome. METHODS: Using untargeted tandem mass tag mass spectrometry, we analyzed CSF from 227 cognitively normal (CN) controls (A–T–), 165 CN A+, and 177 individuals with mild cognitive impairment (MCI A+) from two large cohorts. We compared protein levels across APOE genotypes using linear regression and characterized biological pathways. RESULTS: Five hundred forty-nine of 978 proteins (56%) differed between ε2/ε3 (n = 32 individuals) or ε4 carriers (n = 181 individuals) and ε3/ε3 controls. ε2/ε3 controls showed the most differences, with higher levels of 280 proteins enriched for neuronal plasticity. ε4 carrier controls showed increased proteins linked to blood–brain barrier dysfunction, and A+ ε4 carriers were related to glucose metabolism. DISCUSSION: Combining two cohorts enabled analysis of the rare APOE ε2 genotype, suggesting protective effects may occur through improved neuronal plasticity. Highlights: Apolipoprotein E (APOE) genotypes show distinct cerebrospinal fluid proteomic mechanisms in early Alzheimer's disease (AD). Combining cohorts enabled analysis of rare APOE ε2–associated protection in AD. The rare ε2 genotype may confer protection through improved neuronal plasticity. APOE ε4 carriers show increased blood–brain barrier dysfunction and glucose metabolism. These findings offer new insights into genotype-specific mechanisms in early AD.

    Original languageEnglish
    Article numbere70738
    JournalAlzheimer's and Dementia
    Volume21
    Issue number10
    ISSN1552-5260
    DOIs
    Publication statusPublished - 10.2025

    Funding

    FundersFunder number
    Alzheimer's Association
    Dutch National Dementia Strategy
    Alzheimer Association
    Health Holland
    Familjen Erling-Perssons Stiftelse
    EPND
    European Federation of Pharmaceutical Industries and Associations
    National Institute for Health and Care Research
    Horizon 2020 Framework Programme
    TAP-dementia
    Geestkracht Programme of the Dutch Health Research Council
    Olav Thon Stiftelsen
    Swedish government
    MS Trust and National MS Society
    Innovative Medicines Initiative
    AD Strategic Fund
    Gun och Bertil Stohnes Stiftelse
    Institute of Medical Informatics101034344
    Edwin Bouw Fonds2017‐00915, 2022‐00732
    Stichting Alzheimer Association‐FRA 2021/0022, #SAO-FRA 2021/0022
    ZonMw733050824736, 10510032120003, 09150171910068
    Alzheimerfonden‐968270, ‐930351, ‐939721, -0243, #ALZ2022‐0006
    Stiftung Synapsis - Alzheimer Forschung Schweiz AFS2017‐PI01
    Selfridges Group Foundation73305095007
    Fonds Wetenschappelijk Onderzoek12Y1623N
    Schweizerischer Nationalfonds zur Förderung der Wissenschaftlichen Forschung320030_141179
    EU Joint Programme – Neurodegenerative Disease Research733051111, JPND2021‐00694
    Gamla Tjänarinnor Stiftelse733050512, AFA 200386
    Stiftelsen för Gamla Tjänarinnor, Hjärnfonden, Sweden#FO2022‐0270
    Norges Forskningsråd295910
    European Commission101053962, 71320
    Alzheimer's Drug Discovery Foundation201809‐2016862
    H2020 Marie Skłodowska-Curie Actions860197
    Vetenskapsrådet2019‐02397, 2022‐01018
    UK Dementia Research InstituteUKDRI‐1003
    County Councils965240, 715986
    European Commission831434
    European Union Joint Program for Neurodegenerative DisordersJPND2019‐466‐236, ZEN‐21‐848495, SG‐23‐1038904 QC
    Brain and Behavior Research FoundationFO2018-0315
    EMIF115372
    Seventh Framework ProgrammeFP7/2007-2013

      Research Areas and Centers

      • Research Area: Medical Genetics

      DFG Research Classification Scheme

      • 2.23-06 Molecular and Cellular Neurology and Neuropathology

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