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An aggregation inhibitor specific to oligomeric intermediates of Aβ42 derived from phage display libraries of stable, small proteins

Linse, Sara LU ; Sormanni, Pietro and O’Connell, David J. (2022) In Proceedings of the National Academy of Sciences of the United States of America 119(21).
Abstract

The self-assembly of amyloid β peptide (Aβ) to fibrillar and oligomeric aggregates is linked to Alzheimer’s disease. Aβ binders may serve as inhibitors of aggregation to prevent the generation of neurotoxic species and for the detection of Aβ species. A particular challenge involves finding binders to on-pathway oligomers given their transient nature. Here we construct two phage–display libraries built on the highly inert and stable protein scaffold S100G, one containing a six-residue variable surface patch and one harboring a seven-residue variable loop insertion. Monomers and fibrils of Aβ40 and Aβ42 were separately coupled to silica nanoparticles, using a coupling strategy leading to the presence of oligomers on the monomer beads,... (More)

The self-assembly of amyloid β peptide (Aβ) to fibrillar and oligomeric aggregates is linked to Alzheimer’s disease. Aβ binders may serve as inhibitors of aggregation to prevent the generation of neurotoxic species and for the detection of Aβ species. A particular challenge involves finding binders to on-pathway oligomers given their transient nature. Here we construct two phage–display libraries built on the highly inert and stable protein scaffold S100G, one containing a six-residue variable surface patch and one harboring a seven-residue variable loop insertion. Monomers and fibrils of Aβ40 and Aβ42 were separately coupled to silica nanoparticles, using a coupling strategy leading to the presence of oligomers on the monomer beads, and they were used in three rounds of affinity selection. Next-generation sequencing revealed sequence clusters and candidate binding proteins (SXkmers). Two SXkmers were expressed as soluble proteins and tested in terms of aggregation inhibition via thioflavin T fluorescence. We identified an SXkmer with loop–insertion YLTIRLM as an inhibitor of the secondary nucleation of Aβ42 and binding analyses using surface plasmon resonance technology, F€orster resonance energy transfer, and microfluidics diffusional sizing imply an interaction with intermediate oligomeric species. A linear peptide with the YLTIRLM sequence was found inhibitory but at a lower potency than the more constrained SXkmer loop. We identified an SXkmer with side-patch VI-WI-DD as an inhibitor of Aβ40 aggregation. Remarkably, our data imply that SXkmer-YLTIRLM blocks secondary nucleation through an interaction with oligomeric intermediates in solution or at the fibril surface, which is a unique inhibitory mechanism for a library-derived inhibitor.

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author
; and
organization
publishing date
type
Contribution to journal
publication status
published
subject
keywords
affinity selection, binder, novel scaffold, reaction intermediates, self-assembly
in
Proceedings of the National Academy of Sciences of the United States of America
volume
119
issue
21
article number
e2121966119
publisher
National Academy of Sciences
external identifiers
  • scopus:85131435054
  • pmid:35580187
ISSN
0027-8424
DOI
10.1073/pnas.2121966119
language
English
LU publication?
yes
id
554eea8c-b2e6-4e8a-9d3b-1b34598dabe3
date added to LUP
2022-12-28 15:08:46
date last changed
2024-09-20 07:42:07
@article{554eea8c-b2e6-4e8a-9d3b-1b34598dabe3,
  abstract     = {{<p>The self-assembly of amyloid β peptide (Aβ) to fibrillar and oligomeric aggregates is linked to Alzheimer’s disease. Aβ binders may serve as inhibitors of aggregation to prevent the generation of neurotoxic species and for the detection of Aβ species. A particular challenge involves finding binders to on-pathway oligomers given their transient nature. Here we construct two phage–display libraries built on the highly inert and stable protein scaffold S100G, one containing a six-residue variable surface patch and one harboring a seven-residue variable loop insertion. Monomers and fibrils of Aβ40 and Aβ42 were separately coupled to silica nanoparticles, using a coupling strategy leading to the presence of oligomers on the monomer beads, and they were used in three rounds of affinity selection. Next-generation sequencing revealed sequence clusters and candidate binding proteins (SXkmers). Two SXkmers were expressed as soluble proteins and tested in terms of aggregation inhibition via thioflavin T fluorescence. We identified an SXkmer with loop–insertion YLTIRLM as an inhibitor of the secondary nucleation of Aβ42 and binding analyses using surface plasmon resonance technology, F€orster resonance energy transfer, and microfluidics diffusional sizing imply an interaction with intermediate oligomeric species. A linear peptide with the YLTIRLM sequence was found inhibitory but at a lower potency than the more constrained SXkmer loop. We identified an SXkmer with side-patch VI-WI-DD as an inhibitor of Aβ40 aggregation. Remarkably, our data imply that SXkmer-YLTIRLM blocks secondary nucleation through an interaction with oligomeric intermediates in solution or at the fibril surface, which is a unique inhibitory mechanism for a library-derived inhibitor.</p>}},
  author       = {{Linse, Sara and Sormanni, Pietro and O’Connell, David J.}},
  issn         = {{0027-8424}},
  keywords     = {{affinity selection; binder; novel scaffold; reaction intermediates; self-assembly}},
  language     = {{eng}},
  number       = {{21}},
  publisher    = {{National Academy of Sciences}},
  series       = {{Proceedings of the National Academy of Sciences of the United States of America}},
  title        = {{An aggregation inhibitor specific to oligomeric intermediates of Aβ42 derived from phage display libraries of stable, small proteins}},
  url          = {{http://dx.doi.org/10.1073/pnas.2121966119}},
  doi          = {{10.1073/pnas.2121966119}},
  volume       = {{119}},
  year         = {{2022}},
}