APP and Alzheimer disease: Although the mechanisms of amyloidogenesis by Aβ peptides remain unclear, a growing body of evidence indicates that i) cleavage of APP produces the major Aβ peptides, including Aβ1–40 and Aβ1–42, ii) these Aβ peptides undergo self-polymerization, followed by formation of Aβ oligomers (soluble Aβ), and iii) Aβ oligomers aggregate to form Aβ fibrils or plaques (insoluble Aβ), considered a hallmark of AD [50].