Dataset Information

Kinetic diversity of amyloid oligomers.

ABSTRACT: The spontaneous assembly of proteins into amyloid fibrils is a phenomenon central to many increasingly common and currently incurable human disorders, including Alzheimer's and Parkinson's diseases. Oligomeric species form transiently during this process and not only act as essential intermediates in the assembly of new filaments but also represent major pathogenic agents in these diseases. While amyloid fibrils possess a common, defining set of physicochemical features, oligomers, by contrast, appear much more diverse, and their commonalities and differences have hitherto remained largely unexplored. Here, we use the framework of chemical kinetics to investigate their dynamical properties. By fitting experimental data for several unrelated amyloidogenic systems to newly derived mechanistic models, we find that oligomers present with a remarkably wide range of kinetic and thermodynamic stabilities but that they possess two properties that are generic: they are overwhelmingly nonfibrillar, and they predominantly dissociate back to monomers rather than maturing into fibrillar species. These discoveries change our understanding of the relationship between amyloid oligomers and amyloid fibrils and have important implications for the nature of their cellular toxicity.

SUBMITTER: Dear AJ

PROVIDER: S-EPMC7275774 | biostudies-literature | 2020 Jun

REPOSITORIES: biostudies-literature

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Kinetic diversity of amyloid oligomers.

Dear Alexander J AJ Michaels Thomas C T TCT Meisl Georg G Klenerman David D Wu Si S Perrett Sarah S Linse Sara S Dobson Christopher M CM Knowles Tuomas P J TPJ

Proceedings of the National Academy of Sciences of the United States of America 20200515 22

The spontaneous assembly of proteins into amyloid fibrils is a phenomenon central to many increasingly common and currently incurable human disorders, including Alzheimer's and Parkinson's diseases. Oligomeric species form transiently during this process and not only act as essential intermediates in the assembly of new filaments but also represent major pathogenic agents in these diseases. While amyloid fibrils possess a common, defining set of physicochemical features, oligomers, by contrast, ...[more]

PMID: 32414930

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Project description:Alzheimer's disease begins about two decades before the onset of symptoms or neuron death, and is believed to be caused by pathogenic amyloid-? aggregates that initiate a cascade of molecular events culminating in widespread neurodegeneration. The microtubule binding protein tau may mediate the effects of amyloid-? in this cascade. Amyloid plaques comprised of insoluble, fibrillar amyloid-? aggregates are the most characteristic feature of Alzheimer's disease. However, the correspondence between the distribution of plaques and the pattern of neurodegeneration is tenuous. This discrepancy has stimulated the investigation of other amyloid-? aggregates, including soluble amyloid-? oligomers. Different soluble amyloid-? oligomers have been studied in several mouse models, but not systematically in humans. Here, we measured three amyloid-? oligomers previously described in mouse models-amyloid-? trimers, A?*56 and amyloid-? dimers-in brain tissue from 75 cognitively intact individuals, ranging from young children to the elderly, and 58 impaired subjects with mild cognitive impairment or probable Alzheimer's disease. As in mouse models, where amyloid-? trimers appear to be the fundamental amyloid-? assembly unit of A?*56 and are present in young mice prior to memory decline, amyloid-? trimers in humans were present in children and adolescents; their levels rose gradually with age and were significantly above baseline in subjects in their 70s. A?*56 levels were negligible in children and young adults, rose significantly above baseline in subjects in their 40s and increased steadily thereafter. Amyloid-? dimers were undetectable until subjects were in their 60s; their levels then increased sharply and correlated with plaque load. Remarkably, in cognitively intact individuals we found strong positive correlations between A?*56 and two pathological forms of soluble tau (tau-CP13 and tau-Alz50), and negative correlations between A?*56 and two postsynaptic proteins (drebrin and fyn kinase), but none between amyloid-? dimers or amyloid-? trimers and tau or synaptic proteins. Comparing impaired with age-matched unimpaired subjects, we found the highest levels of amyloid-? dimers, but the lowest levels of A?*56 and amyloid-? trimers, in subjects with probable Alzheimer's disease. In conclusion, in cognitively normal adults A?*56 increased ahead of amyloid-? dimers or amyloid-? trimers, and pathological tau proteins and postsynaptic proteins correlated with A?*56, but not amyloid-? dimers or amyloid-? trimers. We propose that A?*56 may play a pathogenic role very early in the pathogenesis of Alzheimer's disease.

Dataset Information

Kinetic diversity of amyloid oligomers.

Publications

Kinetic diversity of amyloid oligomers.

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