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The role of shear forces in primary and secondary nucleation of amyloid fibrils

Axell, Emil LU ; Hu, Jing LU ; Lindberg, Max LU orcid ; Dear, Alexander J. LU ; Ortigosa-Pascual, Lei LU ; Andrzejewska, Ewa A. LU ; Šneiderienė, Greta ; Thacker, Dev LU ; Knowles, Tuomas P. J. and Sparr, Emma LU , et al. (2024) In Proceedings of the National Academy of Sciences of the United States of America 121(25). p.2322572121-2322572121
Abstract

Shear forces affect self-assembly processes ranging from crystallization to fiber formation. Here, the effect of mild agitation on amyloid fibril formation was explored for four peptides and investigated in detail for Aβ42, which is associated with Alzheimer's disease. To gain mechanistic insights into the effect of mild agitation, nonseeded and seeded aggregation reactions were set up at various peptide concentrations with and without an inhibitor. First, an effect on fibril fragmentation was excluded by comparing the monomer-concentration dependence of aggregation kinetics under idle and agitated conditions. Second, using a secondary nucleation inhibitor, Brichos, the agitation effect on primary nucleation was decoupled from secondary... (More)

Shear forces affect self-assembly processes ranging from crystallization to fiber formation. Here, the effect of mild agitation on amyloid fibril formation was explored for four peptides and investigated in detail for Aβ42, which is associated with Alzheimer's disease. To gain mechanistic insights into the effect of mild agitation, nonseeded and seeded aggregation reactions were set up at various peptide concentrations with and without an inhibitor. First, an effect on fibril fragmentation was excluded by comparing the monomer-concentration dependence of aggregation kinetics under idle and agitated conditions. Second, using a secondary nucleation inhibitor, Brichos, the agitation effect on primary nucleation was decoupled from secondary nucleation. Third, an effect on secondary nucleation was established in the absence of inhibitor. Fourth, an effect on elongation was excluded by comparing the seeding potency of fibrils formed under idle or agitated conditions. We find that both primary and secondary nucleation steps are accelerated by gentle agitation. The increased shear forces facilitate both the detachment of newly formed aggregates from catalytic surfaces and the rate at which molecules are transported in the bulk solution to encounter nucleation sites on the fibril and other surfaces. Ultrastructural evidence obtained with cryogenic transmission electron microscopy and free-flow electrophoresis in microfluidics devices imply that agitation speeds up the detachment of nucleated species from the fibril surface. Our findings shed light on the aggregation mechanism and the role of detachment for efficient secondary nucleation. The results inform on how to modulate the relative importance of different microscopic steps in drug discovery and investigations.

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organization
publishing date
type
Contribution to journal
publication status
published
subject
keywords
Amyloid/metabolism, Kinetics, Humans, Shear Strength, Protein Aggregates, Peptides/chemistry, Alzheimer Disease/metabolism
in
Proceedings of the National Academy of Sciences of the United States of America
volume
121
issue
25
pages
10 pages
publisher
National Academy of Sciences
external identifiers
  • pmid:38875148
ISSN
1091-6490
DOI
10.1073/pnas.2322572121
language
English
LU publication?
yes
id
a93ab385-c50c-4124-ab64-7e7b9907383e
date added to LUP
2024-06-16 00:43:50
date last changed
2024-06-21 03:08:55
@article{a93ab385-c50c-4124-ab64-7e7b9907383e,
  abstract     = {{<p>Shear forces affect self-assembly processes ranging from crystallization to fiber formation. Here, the effect of mild agitation on amyloid fibril formation was explored for four peptides and investigated in detail for Aβ42, which is associated with Alzheimer's disease. To gain mechanistic insights into the effect of mild agitation, nonseeded and seeded aggregation reactions were set up at various peptide concentrations with and without an inhibitor. First, an effect on fibril fragmentation was excluded by comparing the monomer-concentration dependence of aggregation kinetics under idle and agitated conditions. Second, using a secondary nucleation inhibitor, Brichos, the agitation effect on primary nucleation was decoupled from secondary nucleation. Third, an effect on secondary nucleation was established in the absence of inhibitor. Fourth, an effect on elongation was excluded by comparing the seeding potency of fibrils formed under idle or agitated conditions. We find that both primary and secondary nucleation steps are accelerated by gentle agitation. The increased shear forces facilitate both the detachment of newly formed aggregates from catalytic surfaces and the rate at which molecules are transported in the bulk solution to encounter nucleation sites on the fibril and other surfaces. Ultrastructural evidence obtained with cryogenic transmission electron microscopy and free-flow electrophoresis in microfluidics devices imply that agitation speeds up the detachment of nucleated species from the fibril surface. Our findings shed light on the aggregation mechanism and the role of detachment for efficient secondary nucleation. The results inform on how to modulate the relative importance of different microscopic steps in drug discovery and investigations.</p>}},
  author       = {{Axell, Emil and Hu, Jing and Lindberg, Max and Dear, Alexander J. and Ortigosa-Pascual, Lei and Andrzejewska, Ewa A. and Šneiderienė, Greta and Thacker, Dev and Knowles, Tuomas P. J. and Sparr, Emma and Linse, Sara}},
  issn         = {{1091-6490}},
  keywords     = {{Amyloid/metabolism; Kinetics; Humans; Shear Strength; Protein Aggregates; Peptides/chemistry; Alzheimer Disease/metabolism}},
  language     = {{eng}},
  month        = {{06}},
  number       = {{25}},
  pages        = {{2322572121--2322572121}},
  publisher    = {{National Academy of Sciences}},
  series       = {{Proceedings of the National Academy of Sciences of the United States of America}},
  title        = {{The role of shear forces in primary and secondary nucleation of amyloid fibrils}},
  url          = {{http://dx.doi.org/10.1073/pnas.2322572121}},
  doi          = {{10.1073/pnas.2322572121}},
  volume       = {{121}},
  year         = {{2024}},
}