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Novel ultrasensitive immunoassay for the selective quantification of tau oligomers and related soluble aggregates.

Authors :
Islam T
Kvartsberg H
Sehrawat A
Kac PR
Becker B
Olsson M
Abrahamson EE
Zetterberg H
Ikonomovic MD
Blennow K
Karikari TK
Source :
Alzheimer's & dementia : the journal of the Alzheimer's Association [Alzheimers Dement] 2024 Apr; Vol. 20 (4), pp. 2894-2905. Date of Electronic Publication: 2024 Mar 23.
Publication Year :
2024

Abstract

Introduction: Tau aggregation into paired helical filaments and neurofibrillary tangles is characteristic of Alzheimer's disease (AD) and related disorders. However, biochemical assays for the quantification of soluble, earlier-stage tau aggregates are lacking. We describe an immunoassay that is selective for tau oligomers and related soluble aggregates over monomers.<br />Methods: A homogeneous (single-antibody) immunoassay was developed using a novel anti-tau monoclonal antibody and validated with recombinant and brain tissue-derived tau.<br />Results: The assay signals were concentration dependent for recombinant tau aggregates in solution but not monomers, and recognized peptides within, but not outside, the aggregation-prone microtubule binding region. The signals in inferior and middle frontal cortical tissue homogenates increased with neuropathologically determined Braak staging, and were higher in insoluble than soluble homogenized brain fractions. Autopsy-verified AD gave stronger signals than other neurodegenerative diseases.<br />Discussion: The quantitative oligomer/soluble aggregate-specific assay can identify soluble tau aggregates, including oligomers, from monomers in human and in vitro biospecimens.<br />Highlights: The aggregation of tau to form fibrils and neurofibrillary tangles is a key feature of Alzheimer's disease. However, biochemical assays for the quantification of oligomers/soluble aggregated forms of tau are lacking. We developed a new assay that preferentially binds to soluble tau aggregates, including oligomers and fibrils, versus monomers. The assay signal increased corresponding to the total protein content, Braak staging, and insolubility of the sequentially homogenized brain tissue fractions in an autopsy-verified cohort. The assay recognized tau peptides containing the microtubule binding region but not those covering the N- or C-terminal regions only.<br /> (© 2024 The Authors. Alzheimer's & Dementia published by Wiley Periodicals LLC on behalf of Alzheimer's Association.)

Details

Language :
English
ISSN :
1552-5279
Volume :
20
Issue :
4
Database :
MEDLINE
Journal :
Alzheimer's & dementia : the journal of the Alzheimer's Association
Publication Type :
Academic Journal
Accession number :
38520322
Full Text :
https://doi.org/10.1002/alz.13711