Single‐Molecule Characterization and Super‐Resolution Imaging of Alzheimer's Disease‐Relevant Tau Aggregates in Human Samples

• Published in: Angewandte Chemie International Edition 2024-05, Vol.63 (21), p.e202317756-n/a
• Main Authors: Böken, Dorothea, Cox, Dezerae, Burke, Melanie, Lam, Jeff Y. L., Katsinelos, Taxiarchis, Danial, John S. H., Fertan, Emre, McEwan, William A., Rowe, James B., Klenerman, David
• Format: Article
• Language: English
• Subjects: Aggregates; Alzheimer Disease - diagnosis; Alzheimer Disease - metabolism; Alzheimer's disease; Biological properties; Biological samples; Brain - diagnostic imaging; Brain - metabolism; Brain - pathology; fluorescence microscopy; Humans; Molecular structure; neurodegenerative disease; Neurodegenerative diseases; Neuroimaging; Phosphorylation; Protein Aggregates; protein aggregation; proteins; Single Molecule Imaging - methods; single-molecule studies; Subpopulations; Tau protein; tau Proteins - analysis; tau Proteins - chemistry; tau Proteins - metabolism
• ISSN: 1433-7851; 1521-3773; 1521-3773
• DOI: 10.1002/anie.202317756

Hyperphosphorylation and aggregation of the protein tau play key roles in the development of Alzheimer's disease (AD). While the molecular structure of the filamentous tau aggregates has been determined to atomic resolution, there is far less information available about the smaller, soluble aggregates, which are believed to be more toxic. Traditional techniques are limited to bulk measures and struggle to identify individual aggregates in complex biological samples. To address this, we developed a novel single‐molecule pull‐down‐based assay (MAPTau) to detect and characterize individual tau aggregates in AD and control post‐mortem brain and biofluids. Using MAPTau, we report the quantity, as well as the size and circularity of tau aggregates measured using super‐resolution microscopy, revealing AD‐specific differences in tau aggregate morphology. By adapting MAPTau to detect multiple phosphorylation markers in individual aggregates using two‐color coincidence detection, we derived compositional profiles of the individual aggregates. We find an AD‐specific phosphorylation profile of tau aggregates with more than 80 % containing multiple phosphorylations, compared to 5 % in age‐matched non‐AD controls. Our results show that MAPTau is able to identify disease‐specific subpopulations of tau aggregates phosphorylated at different sites, that are invisible to other methods and enable the study of disease mechanisms and diagnosis. Introducing MAPTau, a novel single‐molecule approach for detailed analysis of tau aggregates in human brain and blood, offering unprecedented insights into the quantity, size, and phosphorylation profile of individual tau aggregates. By identifying distinctive Alzheimer's disease‐specific tau aggregate morphologies and phosphorylation patterns, MAPTau opens new avenues for investigating disease mechanisms and novel diagnostic strategies.