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A Biophysical Approach to the Identification of Novel ApoE Chemical Probes

Alzheimer’s disease (AD) is the most common type of dementia and, after age, the greatest risk factor for developing AD is the allelic variation of apolipoprotein E (ApoE), with homozygote carriers of the ApoE4 allele having an up to 12-fold greater risk of developing AD than noncarriers. Apolipopro...

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Autores principales: Kraft, Lucas, Serpell, Louise C., Atack, John R.
Formato: Online Artículo Texto
Lenguaje:English
Publicado: MDPI 2019
Materias:
Acceso en línea:https://www.ncbi.nlm.nih.gov/pmc/articles/PMC6406525/
https://www.ncbi.nlm.nih.gov/pubmed/30700058
http://dx.doi.org/10.3390/biom9020048
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author Kraft, Lucas
Serpell, Louise C.
Atack, John R.
author_facet Kraft, Lucas
Serpell, Louise C.
Atack, John R.
author_sort Kraft, Lucas
collection PubMed
description Alzheimer’s disease (AD) is the most common type of dementia and, after age, the greatest risk factor for developing AD is the allelic variation of apolipoprotein E (ApoE), with homozygote carriers of the ApoE4 allele having an up to 12-fold greater risk of developing AD than noncarriers. Apolipoprotein E exists as three isoforms that differ in only two amino acid sites, ApoE2 (Cys112/Cys158), ApoE3 (Cys112/Arg158), and ApoE4 (Arg112/Arg158). These amino acid substitutions are assumed to alter ApoE structure and function, and be responsible for the detrimental effects of ApoE4 via a mechanism that remains unclear. The hypothesis that a structural difference between ApoE4 and ApoE3 (and ApoE2) is the cause of the ApoE4-associated increased risk for AD forms the basis of a therapeutic approach to modulate ApoE4 structure, and we were therefore interested in screening to identify new chemical probes for ApoE4. In this regard, a high-yield protocol was developed for the expression and purification of recombinant full-length ApoE, and three diverse biophysical screening assays were established and characterized; an optical label-free assay (Corning Epic) for hit identification and microscale thermophoresis (MST) and isothermal titration calorimetry (ITC) as orthogonal assays for hit confirmation. The 707 compounds in the National Institute of Health clinical collection were screened for binding to ApoE4, from which six confirmed hits, as well as one analogue, were identified. Although the compounds did not differentiate between ApoE isoforms, these data nevertheless demonstrate the feasibility of using a biophysical approach to identifying compounds that bind to ApoE and that, with further optimization, might differentiate between isoforms to produce a molecule that selectively alters the function of ApoE4.
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spelling pubmed-64065252019-03-13 A Biophysical Approach to the Identification of Novel ApoE Chemical Probes Kraft, Lucas Serpell, Louise C. Atack, John R. Biomolecules Article Alzheimer’s disease (AD) is the most common type of dementia and, after age, the greatest risk factor for developing AD is the allelic variation of apolipoprotein E (ApoE), with homozygote carriers of the ApoE4 allele having an up to 12-fold greater risk of developing AD than noncarriers. Apolipoprotein E exists as three isoforms that differ in only two amino acid sites, ApoE2 (Cys112/Cys158), ApoE3 (Cys112/Arg158), and ApoE4 (Arg112/Arg158). These amino acid substitutions are assumed to alter ApoE structure and function, and be responsible for the detrimental effects of ApoE4 via a mechanism that remains unclear. The hypothesis that a structural difference between ApoE4 and ApoE3 (and ApoE2) is the cause of the ApoE4-associated increased risk for AD forms the basis of a therapeutic approach to modulate ApoE4 structure, and we were therefore interested in screening to identify new chemical probes for ApoE4. In this regard, a high-yield protocol was developed for the expression and purification of recombinant full-length ApoE, and three diverse biophysical screening assays were established and characterized; an optical label-free assay (Corning Epic) for hit identification and microscale thermophoresis (MST) and isothermal titration calorimetry (ITC) as orthogonal assays for hit confirmation. The 707 compounds in the National Institute of Health clinical collection were screened for binding to ApoE4, from which six confirmed hits, as well as one analogue, were identified. Although the compounds did not differentiate between ApoE isoforms, these data nevertheless demonstrate the feasibility of using a biophysical approach to identifying compounds that bind to ApoE and that, with further optimization, might differentiate between isoforms to produce a molecule that selectively alters the function of ApoE4. MDPI 2019-01-29 /pmc/articles/PMC6406525/ /pubmed/30700058 http://dx.doi.org/10.3390/biom9020048 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
Kraft, Lucas
Serpell, Louise C.
Atack, John R.
A Biophysical Approach to the Identification of Novel ApoE Chemical Probes
title A Biophysical Approach to the Identification of Novel ApoE Chemical Probes
title_full A Biophysical Approach to the Identification of Novel ApoE Chemical Probes
title_fullStr A Biophysical Approach to the Identification of Novel ApoE Chemical Probes
title_full_unstemmed A Biophysical Approach to the Identification of Novel ApoE Chemical Probes
title_short A Biophysical Approach to the Identification of Novel ApoE Chemical Probes
title_sort biophysical approach to the identification of novel apoe chemical probes
topic Article
url https://www.ncbi.nlm.nih.gov/pmc/articles/PMC6406525/
https://www.ncbi.nlm.nih.gov/pubmed/30700058
http://dx.doi.org/10.3390/biom9020048
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