title: Mixed ligand Cu2+ complexes of a model therapeutic with Alzheimer's amyloid-β peptide and monoamine neurotransmitters.
abstract: 8-Hydroxyquinolines (8HQ) have found widespread application in chemistry and biology due to their ability to complex a range of transition metal ions. The family of 2-substituted 8HQs has been proposed for use in the treatment of Alzheimer's disease (AD). Most notably, the therapeutic PBT2 (Prana Biotechnology Ltd.) has been shown to act as an efficient metal chaperone, disaggregate metal-enriched amyloid plaques comprised of the Aβ peptide, inhibit Cu/Aβ redox chemistry, and reverse the AD phenotype in transgenic animal models. Yet surprisingly little is known about the molecular interactions at play. In this study, we show that the homologous ligand 2-[(dimethylamino)methyl]-8-hydroxyquinoline (HL) forms a CuL complex with a conditional (apparent) dissociation constant of 0.33 nM at pH 6.9 and is capable of forming ternary Cu(2+) complexes with neurotransmitters including histamine (HA), glutamic acid (Glu), and glycine (Gly), with glutathione disulfide (GSSG), and with histidine (His) side chains of proteins and peptides including the Aβ peptide. Our findings suggest a molecular basis for the strong metal chaperone activity of PBT2, its ability to attenuate Cu(2+)/Aβ interactions, and its potential to promote neuroprotective and neuroregenerative effects.
authors.affiliation: Mental Health Research Institute, The University of Melbourne, Victoria 3010, Australia.
authors.forename: Vijaya B
authors.initials: VB
authors.lastname: Kenche
authors.forename: Izabela
authors.initials: I
authors.lastname: Zawisza
authors.forename: Colin L
authors.initials: CL
authors.lastname: Masters
authors.forename: Wojciech
authors.initials: W
authors.lastname: Bal
authors.forename: Kevin J
authors.initials: KJ
authors.lastname: Barnham
authors.forename: Simon C
authors.initials: SC
authors.lastname: Drew
mesh_terms: D000544:Alzheimer Disease / Q000188:drug therapy* / Q000378:metabolism; D016229:Amyloid beta-Peptides / Q000378:metabolism*; D003300:Copper / Q000737:chemistry* / Q000494:pharmacology*; D018698:Glutamic Acid / Q000378:metabolism; D019803:Glutathione Disulfide / Q000378:metabolism; D005998:Glycine / Q000378:metabolism; D006632:Histamine / Q000378:metabolism; D006639:Histidine / Q000378:metabolism; D006801:Humans; D008024:Ligands; D008958:Models, Molecular; D018377:Neurotransmitter Agents / Q000378:metabolism; D015125:Oxyquinoline / Q000031:analogs & derivatives* / Q000494:pharmacology*
chemical_list: D016229:Amyloid beta-Peptides; D008024:Ligands; D018377:Neurotransmitter Agents; D018698:Glutamic Acid; D006639:Histidine; D015125:Oxyquinoline; D003300:Copper; D006632:Histamine; D005998:Glycine; D019803:Glutathione Disulfide