The role of shear forces in primary and secondary nucleation of amyloid fibrils
(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.
(Less)
- author
- organization
- publishing date
- 2024-06-18
- 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
- scopus:85196236157
- 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
- 2024-09-15 08:08:59
@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}}, }