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Kinetic Transition in Amyloid Assembly as a Screening Assay for Oligomer-Selective Dyes

Assembly of amyloid fibrils and small globular oligomers is associated with a significant number of human disorders that include Alzheimer’s disease, senile systemic amyloidosis, and type II diabetes. Recent findings implicate small amyloid oligomers as the dominant aggregate species mediating the t...

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Autores principales: Barton, Jeremy, Arias, D. Sebastian, Niyangoda, Chamani, Borjas, Gustavo, Le, Nathan, Mohamed, Saefallah, Muschol, Martin
Formato: Online Artículo Texto
Lenguaje:English
Publicado: MDPI 2019
Materias:
Acceso en línea:https://www.ncbi.nlm.nih.gov/pmc/articles/PMC6843685/
https://www.ncbi.nlm.nih.gov/pubmed/31569739
http://dx.doi.org/10.3390/biom9100539
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author Barton, Jeremy
Arias, D. Sebastian
Niyangoda, Chamani
Borjas, Gustavo
Le, Nathan
Mohamed, Saefallah
Muschol, Martin
author_facet Barton, Jeremy
Arias, D. Sebastian
Niyangoda, Chamani
Borjas, Gustavo
Le, Nathan
Mohamed, Saefallah
Muschol, Martin
author_sort Barton, Jeremy
collection PubMed
description Assembly of amyloid fibrils and small globular oligomers is associated with a significant number of human disorders that include Alzheimer’s disease, senile systemic amyloidosis, and type II diabetes. Recent findings implicate small amyloid oligomers as the dominant aggregate species mediating the toxic effects in these disorders. However, validation of this hypothesis has been hampered by the dearth of experimental techniques to detect, quantify, and discriminate oligomeric intermediates from late-stage fibrils, in vitro and in vivo. We have shown that the onset of significant oligomer formation is associated with a transition in thioflavin T kinetics from sigmoidal to biphasic kinetics. Here we showed that this transition can be exploited for screening fluorophores for preferential responses to oligomer over fibril formation. This assay identified crystal violet as a strongly selective oligomer-indicator dye for lysozyme. Simultaneous recordings of amyloid kinetics with thioflavin T and crystal violet enabled us to separate the combined signals into their underlying oligomeric and fibrillar components. We provided further evidence that this screening assay could be extended to amyloid-β peptides under physiological conditions. Identification of oligomer-selective dyes not only holds the promise of biomedical applications but provides new approaches for unraveling the mechanisms underlying oligomer versus fibril formation in amyloid assembly.
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spelling pubmed-68436852019-11-25 Kinetic Transition in Amyloid Assembly as a Screening Assay for Oligomer-Selective Dyes Barton, Jeremy Arias, D. Sebastian Niyangoda, Chamani Borjas, Gustavo Le, Nathan Mohamed, Saefallah Muschol, Martin Biomolecules Article Assembly of amyloid fibrils and small globular oligomers is associated with a significant number of human disorders that include Alzheimer’s disease, senile systemic amyloidosis, and type II diabetes. Recent findings implicate small amyloid oligomers as the dominant aggregate species mediating the toxic effects in these disorders. However, validation of this hypothesis has been hampered by the dearth of experimental techniques to detect, quantify, and discriminate oligomeric intermediates from late-stage fibrils, in vitro and in vivo. We have shown that the onset of significant oligomer formation is associated with a transition in thioflavin T kinetics from sigmoidal to biphasic kinetics. Here we showed that this transition can be exploited for screening fluorophores for preferential responses to oligomer over fibril formation. This assay identified crystal violet as a strongly selective oligomer-indicator dye for lysozyme. Simultaneous recordings of amyloid kinetics with thioflavin T and crystal violet enabled us to separate the combined signals into their underlying oligomeric and fibrillar components. We provided further evidence that this screening assay could be extended to amyloid-β peptides under physiological conditions. Identification of oligomer-selective dyes not only holds the promise of biomedical applications but provides new approaches for unraveling the mechanisms underlying oligomer versus fibril formation in amyloid assembly. MDPI 2019-09-27 /pmc/articles/PMC6843685/ /pubmed/31569739 http://dx.doi.org/10.3390/biom9100539 Text en © 2019 by the authors. Licensee MDPI, Basel, Switzerland. This article is an open access article distributed under the terms and conditions of the Creative Commons Attribution (CC BY) license (http://creativecommons.org/licenses/by/4.0/).
spellingShingle Article
Barton, Jeremy
Arias, D. Sebastian
Niyangoda, Chamani
Borjas, Gustavo
Le, Nathan
Mohamed, Saefallah
Muschol, Martin
Kinetic Transition in Amyloid Assembly as a Screening Assay for Oligomer-Selective Dyes
title Kinetic Transition in Amyloid Assembly as a Screening Assay for Oligomer-Selective Dyes
title_full Kinetic Transition in Amyloid Assembly as a Screening Assay for Oligomer-Selective Dyes
title_fullStr Kinetic Transition in Amyloid Assembly as a Screening Assay for Oligomer-Selective Dyes
title_full_unstemmed Kinetic Transition in Amyloid Assembly as a Screening Assay for Oligomer-Selective Dyes
title_short Kinetic Transition in Amyloid Assembly as a Screening Assay for Oligomer-Selective Dyes
title_sort kinetic transition in amyloid assembly as a screening assay for oligomer-selective dyes
topic Article
url https://www.ncbi.nlm.nih.gov/pmc/articles/PMC6843685/
https://www.ncbi.nlm.nih.gov/pubmed/31569739
http://dx.doi.org/10.3390/biom9100539
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