RESUMO
The effects of the Alzheimer's disease (AD)-associated Amyloid-ß (Aß) peptides on platelet aggregation have been previously assessed, but most of these studies focused on Aß40 species. It also remains to be determined which distinct forms of Aß peptides exert differential effects on platelets. In AD, oligomeric Aß42 species is widely thought to be a major contributor to the disease pathogenesis. We, therefore, examine the ability of oligomeric and fibrillary Aß42 to affect platelet aggregation. We show that both forms of Aß42 induced significant platelet aggregation and that it is a novel ligand for the platelet receptor GPVI. Furthermore, a novel binding peptide that reduces the formation of soluble Aß42 oligomers was effective at preventing Aß42-dependent platelet aggregation. These results support a role for Aß42 oligomers in platelet hyperactivity.