Distinct populations of highly potent TAU seed conformers in rapidly progressing Alzheimer's disease

Although genetic factors play a main role in determining the risk of developing Alzheimer's disease (AD), they do not explain extensive spectrum of clinicopathological phenotypes. Deposits of aggregated TAU proteins are one of the main predictors of cognitive decline in AD. We investigated the hypothesis that variabilities in AD progression could be due to diverse structural assemblies (strains) of TAU protein. Using sensitive biophysical methods in 40 patients with AD and markedly different disease durations, we identified populations of distinct TAU particles that differed in size, structural organization, and replication rate in vitro and in cell assay. The rapidly replicating, distinctly misfolded TAU conformers found in rapidly progressive AD were composed of similar to 80% misfolded four-repeat (4R) TAU and similar to 20% of misfolded 3R TAU isoform with the same conformational signatures. These biophysical observations suggest that distinctly misfolded population of 4R TAU conformers drive the rapid decline in AD and imply that effective therapeutic strategies might need to consider not a singular species but a cloud of differently misfolded TAU conformers.

Automated summary

This study suggests that the variability in Alzheimer's disease progression could be attributed to different structural assemblies of TAU protein. Specifically, the rapidly replicating, misfolded TAU conformers found in rapidly progressive AD may drive the rapid decline in the disease. This finding implies that effective therapeutic strategies for AD might need to consider the diverse misfolded TAU conformers rather than a singular species.