Alzheimer's disease (AD) and cataract represent two common protein misfolding diseases closely associated with aging. Growing evidence suggests that these two diseases may be interrelated with each other through cross-sequence interactions between β-amyloid (Aβ) peptide and the short aggregating peptides derived from proteolytic breakdown of α-crystallin. αΑ(66-80) is one of several peptides produced by the proteolytic breakdown of α-crystallin in aged eye lens. Although it is evident that the Aβ(1-40) and αΑ(66-80) coexist in aged eye lenses and both the peptides are known to form macromolecular assemblies, their cross-sequence interaction and the seeding behavior are not known. In this study, the aggregation behavior of αΑ(66-80) has been examined in the presence of Aβ(1-40) on using thioflavin T (ThT) based aggregation kinetics. The presence of monomeric Aβ(1-40) augmented the aggregation kinetics of αΑ(66-80) and reduced the lag time of αΑ(66-80) aggregation. However, the addition of Aβ(1-40) or αΑ(66-80) fibrils (seeds) didn't result in any change in the rate of αΑ(66-80) aggregation. In this in vitro study, we could show that the presence Aβ(1-40) has substantial effect on the aggregation of αΑ(66-80), which suggests a possible interaction between AD and cataract pathologies.
Keywords: Aging; Amyloids; Cataract; Cross-sequence interaction; Degenerative diseases.
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