Sequestration of copper from β-amyloid promotes selective lysis by cyclen-hybrid cleavage agents

Abstract

Decelerated degradation of β-amyloid (Aβ) and its interaction with synaptic copper may be pathogenic in Alzheimer disease. Recently, Co(III)-cyclen tagged to an aromatic recognition motif was shown to degrade Aβ in vitro. Here, we report that apocyclen attached to selective Aβ recognition motifs (KLVFF or curcumin) can capture copper bound to Aβ and use the Cu(II) in place of Co(III) to become proteolytically active. The resultant complexes interfere with Aβ aggregation, degrade Aβ into fragments, preventing H2O2 formation and toxicity in neuronal cell culture. Because Aβ binds Cu in amyloid plaques, apocyclen-tagged targeting molecules may be a promising approach to the selective degradation of Aβ in Alzheimer disease. The principle of copper capture could generalize to other amyloidoses where copper is implicated. © 2008 by The American Society for Biochemistry and Molecular Biology, Inc.