A single fibril study reveals that ApoE inhibits the elongation of Aβ42 fibrils in an isoform-dependent manner

Abstract ApoE-ε4 is the strongest genetic risk factor for late-onset Alzheimer’s disease (AD), linked to increased amyloid-β (Aβ) deposition in the brain. In AD mouse models, microglial expression of apoE3 reduces amyloid plaque burden through enhanced phagocytosis, whereas apoE4 is associated with...

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Main Authors: Sourav Dasadhikari, Shamasree Ghosh, Sudip Pal, Tuomas P. J. Knowles, Kanchan Garai
Format: Article
Language:English
Published: Nature Portfolio 2025-04-01
Series:Communications Chemistry
Online Access:https://doi.org/10.1038/s42004-025-01524-z
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author Sourav Dasadhikari
Shamasree Ghosh
Sudip Pal
Tuomas P. J. Knowles
Kanchan Garai
author_facet Sourav Dasadhikari
Shamasree Ghosh
Sudip Pal
Tuomas P. J. Knowles
Kanchan Garai
author_sort Sourav Dasadhikari
collection DOAJ
description Abstract ApoE-ε4 is the strongest genetic risk factor for late-onset Alzheimer’s disease (AD), linked to increased amyloid-β (Aβ) deposition in the brain. In AD mouse models, microglial expression of apoE3 reduces amyloid plaque burden through enhanced phagocytosis, whereas apoE4 is associated with impaired Aβ clearance. However, the isoform-specific interactions of apoE with Aβ aggregates and the molecular mechanisms by which these isoforms influence Aβ aggregation and clearance remain poorly understood, which is critical for developing potential therapeutic interventions. Here, we employed TIRFM, superresolution microscopy, and single-molecule photobleaching techniques to investigate the isoform-specific effects of apoE on the rate constants of Aβ42 aggregation at the single-fibril level, as well as to quantify the binding affinity and specificity of apoE isoforms to individual Aβ fibril ends. Our results show that apoE4 is ca. 4–5 times less effective than apoE3 and apoE2 in inhibiting fibril elongation, while secondary nucleation is largely unaffected by any of the isoforms. Furthermore, apoE3 exhibits stronger and more specific binding to fibril ends compared to apoE4. These findings suggest that apoE4’s reduced affinity for growing fibril ends may impair microglial clearance and increase amyloid deposition through a higher elongation rate in the brain of ApoE-ε4 carriers.
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spelling doaj-art-60dd6db78b2c4221bf5561fcd2de0cc32025-08-20T02:11:22ZengNature PortfolioCommunications Chemistry2399-36692025-04-018111210.1038/s42004-025-01524-zA single fibril study reveals that ApoE inhibits the elongation of Aβ42 fibrils in an isoform-dependent mannerSourav Dasadhikari0Shamasree Ghosh1Sudip Pal2Tuomas P. J. Knowles3Kanchan Garai4TIFR Centre for Interdisciplinary SciencesTIFR Centre for Interdisciplinary SciencesTIFR Centre for Interdisciplinary SciencesCentre for Misfolding Diseases, Yusuf Hamied Department of Chemistry, University of CambridgeTIFR Centre for Interdisciplinary SciencesAbstract ApoE-ε4 is the strongest genetic risk factor for late-onset Alzheimer’s disease (AD), linked to increased amyloid-β (Aβ) deposition in the brain. In AD mouse models, microglial expression of apoE3 reduces amyloid plaque burden through enhanced phagocytosis, whereas apoE4 is associated with impaired Aβ clearance. However, the isoform-specific interactions of apoE with Aβ aggregates and the molecular mechanisms by which these isoforms influence Aβ aggregation and clearance remain poorly understood, which is critical for developing potential therapeutic interventions. Here, we employed TIRFM, superresolution microscopy, and single-molecule photobleaching techniques to investigate the isoform-specific effects of apoE on the rate constants of Aβ42 aggregation at the single-fibril level, as well as to quantify the binding affinity and specificity of apoE isoforms to individual Aβ fibril ends. Our results show that apoE4 is ca. 4–5 times less effective than apoE3 and apoE2 in inhibiting fibril elongation, while secondary nucleation is largely unaffected by any of the isoforms. Furthermore, apoE3 exhibits stronger and more specific binding to fibril ends compared to apoE4. These findings suggest that apoE4’s reduced affinity for growing fibril ends may impair microglial clearance and increase amyloid deposition through a higher elongation rate in the brain of ApoE-ε4 carriers.https://doi.org/10.1038/s42004-025-01524-z
spellingShingle Sourav Dasadhikari
Shamasree Ghosh
Sudip Pal
Tuomas P. J. Knowles
Kanchan Garai
A single fibril study reveals that ApoE inhibits the elongation of Aβ42 fibrils in an isoform-dependent manner
Communications Chemistry
title A single fibril study reveals that ApoE inhibits the elongation of Aβ42 fibrils in an isoform-dependent manner
title_full A single fibril study reveals that ApoE inhibits the elongation of Aβ42 fibrils in an isoform-dependent manner
title_fullStr A single fibril study reveals that ApoE inhibits the elongation of Aβ42 fibrils in an isoform-dependent manner
title_full_unstemmed A single fibril study reveals that ApoE inhibits the elongation of Aβ42 fibrils in an isoform-dependent manner
title_short A single fibril study reveals that ApoE inhibits the elongation of Aβ42 fibrils in an isoform-dependent manner
title_sort single fibril study reveals that apoe inhibits the elongation of aβ42 fibrils in an isoform dependent manner
url https://doi.org/10.1038/s42004-025-01524-z
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