Citrullination of Amyloid-ß Peptides in Alzheimer's Disease.
ACS Chem Neurosci
; 12(19): 3719-3732, 2021 10 06.
Article
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| MEDLINE
| ID: mdl-34519476
ABSTRACT
Protein citrullination (deimination of arginine residue) is a well-known biomarker of inflammation. Elevated protein citrullination has been shown to colocalize with extracellular amyloid plaques in postmortem AD patient brains. Amyloid-ß (Aß) peptides which aggregate and accumulate in the plaques of Alzheimer's disease (AD) have sequential N-terminal truncations and multiple post-translational modifications (PTM) such as isomerization, pyroglutamate formation, phosphorylation, nitration, and dityrosine cross-linking. However, no conclusive biochemical evidence exists whether citrullinated Aß is present in AD brains. In this study, using high-resolution mass spectrometry, we have identified citrullination of Aß in sporadic and familial AD brains by characterizing the tandem mass spectra of endogenous N-truncated citrullinated Aß peptides. Our quantitative estimations demonstrate that â¼ 35% of pyroglutamate3-Aß pool was citrullinated in plaques in the sporadic AD temporal cortex and â¼ 22% in the detergent-insoluble frontal cortex fractions. Similarly, hypercitrullinated pyroglutamate3-Aß (â¼ 30%) was observed in both the detergent-soluble as well as insoluble Aß pool in familial AD cases. Our results indicate that a common mechanism for citrullination of Aß exists in both the sporadic and familial AD. We establish that citrullination of Aß is a remarkably common PTM, closely associated with pyroglutamate3-Aß formation and its accumulation in AD. This may have implications for Aß toxicity, autoantigenicity of Aß, and may be relevant for the design of diagnostic assays and therapeutic targeting.
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Banco de datos:
MEDLINE
Asunto principal:
Péptidos beta-Amiloides
/
Enfermedad de Alzheimer
Límite:
Humans
Idioma:
En
Año:
2021
Tipo del documento:
Article