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A biophysical approach to the identification of novel ApoE chemical probes

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posted on 2023-06-09, 16:41 authored by Lucas Kraft, Louise SerpellLouise Serpell, John Atack
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.

History

Publication status

  • Published

File Version

  • Published version

Journal

Biomolecules

ISSN

2218-273X

Publisher

MDPI

Issue

2

Volume

9

Page range

48 1-16

Department affiliated with

  • Biochemistry Publications

Research groups affiliated with

  • Dementia Research Group Publications

Full text available

  • Yes

Peer reviewed?

  • Yes

Legacy Posted Date

2019-01-30

First Open Access (FOA) Date

2019-01-30

First Compliant Deposit (FCD) Date

2019-01-29

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