| 1. |
- Linse, Sara, et al.
(författare)
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Kinetic fingerprints differentiate the mechanisms of action of anti-Aβ antibodies
- 2020
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Ingår i: Nature Structural and Molecular Biology. - : Springer Science and Business Media LLC. - 1545-9993 .- 1545-9985. ; 27:12, s. 1125-1133
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Tidskriftsartikel (refereegranskat)abstract
- The amyloid cascade hypothesis, according to which the self-assembly of amyloid-β peptide (Aβ) is a causative process in Alzheimer’s disease, has driven many therapeutic efforts for the past 20 years. Failures of clinical trials investigating Aβ-targeted therapies have been interpreted as evidence against this hypothesis, irrespective of the characteristics and mechanisms of action of the therapeutic agents, which are highly challenging to assess. Here, we combine kinetic analyses with quantitative binding measurements to address the mechanism of action of four clinical stage anti-Aβ antibodies, aducanumab, gantenerumab, bapineuzumab and solanezumab. We quantify the influence of these antibodies on the aggregation kinetics and on the production of oligomeric aggregates and link these effects to the affinity and stoichiometry of each antibody for monomeric and fibrillar forms of Aβ. Our results reveal that, uniquely among these four antibodies, aducanumab dramatically reduces the flux of Aβ oligomers.
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| 2. |
- O'Malley, Tiernan T., et al.
(författare)
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A beta dimers differ from monomers in structural propensity, aggregation paths and population of synaptotoxic assemblies
- 2014
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Ingår i: Biochemical Journal. - 0264-6021. ; 461, s. 413-426
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Tidskriftsartikel (refereegranskat)abstract
- Dimers of A beta (amyloid beta-protein) are believed to play an important role in Alzheimer's disease. In the absence of sufficient brain-derived dimers, we studied one of the only possible dimers that could be produced in vivo, [A beta](DiY) (dityrosine cross-linked A beta). For comparison, we used the A beta monomer and a design dimer cross-linked by replacement of Ser(26) with cystine [A beta S26C](2). We showed that similar to monomers, unaggregated dimers lack appreciable structure and fail to alter long-term potentiation. Importantly, dimers exhibit subtly different structural propensities from monomers and each other, and can self-associate to form larger assemblies. Although [A beta](DiY) and [A beta S26C](2) have distinct aggregation pathways, they both populate bioactive soluble assemblies for longer durations than A beta monomers. Our results indicate that the link between A beta dimers and Alzheimer's disease results from the ability of dimers to further assemble and form synaptotoxic assemblies that persist for long periods of time.
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| 3. |
- O’Malley, Tiernan T., et al.
(författare)
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Production and use of recombinant Aβ for aggregation studies
- 2018
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Ingår i: Methods in Molecular Biology. - New York, NY : Springer New York. - 1064-3745. ; 1777, s. 307-320
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Bokkapitel (refereegranskat)abstract
- The amyloid β-protein (Aβ) is believed to play a central role in Alzheimer’s disease (AD) pathogenesis and there is great interest in understanding the process of Aβ aggregation, its underlying mechanism and the species generated during aggregation and their biological activity. Although Aβ has been studied for more than 30 years, analysis of its aggregation has been hampered by structural and chemical impurities. Here we provide a detailed protocol for the expression and purification of chemically and structurally homogeneous Aβ monomer. We also describe a method to produce covalent Aβ dimers linked by phenolic coupling of tyrosine residues.
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| 4. |
- O'Malley, Tiernan T., et al.
(författare)
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The Aggregation Paths and Products of Aβ42 Dimers Are Distinct from Those of the Aβ42 Monomer
- 2016
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Ingår i: Biochemistry. - : American Chemical Society (ACS). - 0006-2960 .- 1520-4995. ; 55:44, s. 6150-6161
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Tidskriftsartikel (refereegranskat)abstract
- Extracts of Alzheimer's disease (AD) brain that contain what appear to be sodium dodecyl sulfate-stable amyloid β-protein (Aβ) dimers potently block LTP and impair memory consolidation. Brain-derived dimers can be physically separated the Aβ monomer, consist primarily of Aβ42, and resist denaturation by chaotropic agents. In nature, covalently cross-linked Aβ dimers could be generated in two ways: by the formation of a dityrosine (DiY) or an isopeptide ϵ-(γ-glutamyl)-lysine (Q-K) bond. We enzymatically cross-linked recombinant Aβ42 monomer to produce DiY and Q-K dimers and then used a range of biophysical methods to study their aggregation. Both Q-K and DiY dimers aggregate to form soluble assemblies distinct from the fibrillar aggregates formed by the Aβ monomer. The results suggest that the cross-links disfavor fibril formation from Aβ dimers, thereby enhancing the concentration of soluble aggregates akin to those in aqueous extracts of AD brain. Thus, it seems that Aβ dimers may play an important role in determining the formation of soluble rather than insoluble aggregates.
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| 5. |
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