Beta Amyloid Peptide:Research Paper: Concentration-dependent interactions of amphiphilic PiB- derivative metal complexes with amyloid peptides Aβ and amylin

Concentration-dependent interactions of amphiphilic PiB- derivative metal complexes with amyloid peptides Aβ and amylin

Abstract

Metal chelates targeted to amyloid peptides are widely explored as diagnostic tools or therapeutic agents. The attachment of a metal complex to amyloid recognition units typically leads to a decrease in peptide affinity. We show here that by separating a macrocyclic GdL chelate and a PiB targeting unit with a long hydrophobic C10 linker, it is possible to attain nanomolar affinities for both Aβ 1-40 ( K d = 4.4 nM) and amylin ( K d = 4.5 nM), implicated respectively in Alzheimer's disease and diabetes. The Scatchard analysis of surface plasmon resonance data obtained for a series of amphiphilic, PiB derivative GdL complexes indicate that their Aβ 1-40 or amylin binding affinity varies with their concentration, thus micellar aggregation state. The GdL chelates also affect peptide aggregation kinetics, as probed by thioflavin-T fluorescence assays. A 2D NMR study allowed identifying that the hydrophilic region of Aβ 1-40 is involved in the interaction between the monomer peptide and the Gd 3+ complex. Finally, ex vivo biodistribution experiments were conducted in healthy mice by using 111 In labelled analogues. Their pancreatic uptake, ~3%ID/g, is promising to envisage amylin imaging in diabetic animals.

Keywords: Ab; amylin; amyloid peptide; metal complex; micellar aggregation.

© 2020 Wiley-VCH GmbH.

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