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Dityrosine cross-links are present in alzheimer's disease-derived Tau Oligomers and Paired Helical Filaments (PHF) which Promotes the stability of the PHF-core Tau (297–391) in vitro

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posted on 2023-06-10, 05:10 authored by Mahmoud MainaMahmoud Maina, Youssra Al-Hilaly, Sebastian OakleySebastian Oakley, Gunasekhar Burra, Tahmida KhanomTahmida Khanom, Luca Biasetti, Kurtis Mengham, Karen MarshallKaren Marshall, Charles R Harrington, Claude M Wischik, Louise SerpellLouise Serpell
A characteristic hallmark of Alzheimer's Disease (AD) is the pathological aggregation and deposition of tau into paired helical filaments (PHF) in neurofibrillary tangles (NFTs). Oxidative stress is an early event during AD pathogenesis and is associated with tau-mediated AD pathology. Oxidative environments can result in the formation of covalent dityrosine crosslinks that can increase protein stability and insolubility. Dityrosine cross-linking has been shown in Aß plaques in AD and a-synuclein aggregates in Lewy bodies in ex vivo tissue sections, and this modification may increase the insolubility of these aggregates and their resistance to degradation. Using the PHF-core tau fragment (residues 297 – 391) as a model, we have previously demonstrated that dityrosine formation traps tau assemblies to reduce further elongation. However, it is unknown whether dityrosine crosslinks are found in tau deposits in vivo in AD and its relevance to disease mechanism is unclear. Here, using transmission electron microscope (TEM) double immunogold-labelling, we reveal that neurofibrillary NFTs in AD are heavily decorated with dityrosine crosslinks alongside tau. Single immunogold-labelling TEM and fluorescence spectroscopy revealed the presence of dityrosine on AD brain-derived tau oligomers and fibrils. Using the tau (297–391) PHF-core fragment as a model, we further showed that prefibrillar tau species are more amenable to dityrosine crosslinking than tau fibrils. Dityrosine formation results in heat and SDS stability of oxidised prefibrillar and fibrillar tau assemblies. This finding has implications for understanding the mechanism governing the insolubility and toxicity of tau assemblies in vivo.

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Publication status

  • Published

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  • Published version

Journal

Journal of Molecular Biology

ISSN

0022-2836

Publisher

Elsevier BV

Issue

19

Volume

434

Page range

a167785 1-14

Event location

Netherlands

Department affiliated with

  • Biochemistry Publications

Full text available

  • Yes

Peer reviewed?

  • Yes

Legacy Posted Date

2022-10-18

First Open Access (FOA) Date

2022-10-18

First Compliant Deposit (FCD) Date

2022-10-18

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