title: Identification of a Compound That Disrupts Binding of Amyloid-β to the Prion Protein Using a Novel Fluorescence-based Assay.
abstract: The prion protein (PrP) has been implicated both in prion diseases such as Creutzfeldt-Jakob disease, where its monomeric cellular isoform (PrP(C)) is recruited into pathogenic self-propagating polymers of misfolded protein, and in Alzheimer disease, where PrP(C) may act as a receptor for synaptotoxic oligomeric forms of amyloid-β (Aβ). There has been considerable interest in identification of compounds that bind to PrP(C), stabilizing its native fold and thereby acting as pharmacological chaperones to block prion propagation and pathogenesis. However, compounds binding PrP(C) could also inhibit the binding of toxic Aβ species and may have a role in treating Alzheimer disease, a highly prevalent dementia for which there are currently no disease-modifying treatments. However, the absence of a unitary, readily measurable, physiological function of PrP makes screening for ligands challenging, and the highly heterogeneous nature of Aβ oligomer preparations makes conventional competition binding assays difficult to interpret. We have therefore developed a high-throughput screen that utilizes site-specifically fluorescently labeled protein to identify compounds that bind to PrP and inhibit both Aβ binding and prion propagation. Following a screen of 1,200 approved drugs, we identified Chicago Sky Blue 6B as the first small molecule PrP ligand capable of inhibiting Aβ binding, demonstrating the feasibility of development of drugs to block this interaction. The interaction of Chicago Sky Blue 6B was characterized by isothermal titration calorimetry, and its ability to inhibit Aβ binding and reduce prion levels was established in cell-based assays.
authors.affiliation: From the Medical Research Council (MRC) Prion Unit and Department of Neurodegenerative Disease, University College London (UCL) Institute of Neurology, London WC1N 3BG, United Kingdom.
authors.forename: Emmanuel
authors.initials: E
authors.lastname: Risse
authors.affiliation: From the Medical Research Council (MRC) Prion Unit and Department of Neurodegenerative Disease, University College London (UCL) Institute of Neurology, London WC1N 3BG, United Kingdom.
authors.forename: Andrew J
authors.initials: AJ
authors.lastname: Nicoll
authors.affiliation: From the Medical Research Council (MRC) Prion Unit and Department of Neurodegenerative Disease, University College London (UCL) Institute of Neurology, London WC1N 3BG, United Kingdom.
authors.forename: William A
authors.initials: WA
authors.lastname: Taylor
authors.affiliation: From the Medical Research Council (MRC) Prion Unit and Department of Neurodegenerative Disease, University College London (UCL) Institute of Neurology, London WC1N 3BG, United Kingdom.
authors.forename: Daniel
authors.initials: D
authors.lastname: Wright
authors.affiliation: From the Medical Research Council (MRC) Prion Unit and Department of Neurodegenerative Disease, University College London (UCL) Institute of Neurology, London WC1N 3BG, United Kingdom.
authors.forename: Mayank
authors.initials: M
authors.lastname: Badoni
authors.affiliation: From the Medical Research Council (MRC) Prion Unit and Department of Neurodegenerative Disease, University College London (UCL) Institute of Neurology, London WC1N 3BG, United Kingdom.
authors.forename: Xiaofan
authors.initials: X
authors.lastname: Yang
authors.affiliation: From the Medical Research Council (MRC) Prion Unit and Department of Neurodegenerative Disease, University College London (UCL) Institute of Neurology, London WC1N 3BG, United Kingdom m.farrow@prion.ucl.ac.uk.
authors.forename: Mark A
authors.initials: MA
authors.lastname: Farrow
authors.affiliation: From the Medical Research Council (MRC) Prion Unit and Department of Neurodegenerative Disease, University College London (UCL) Institute of Neurology, London WC1N 3BG, United Kingdom j.collinge@prion.ucl.ac.uk.
authors.forename: John
authors.initials: J
authors.lastname: Collinge
mesh_terms: D016229:Amyloid beta-Peptides / Q000235:genetics / Q000378:metabolism*; D002151:Calorimetry; D055808:Drug Discovery; D057166:High-Throughput Screening Assays; D006801:Humans; D018621:PrPC Proteins / Q000235:genetics / Q000378:metabolism*; D011485:Protein Binding / Q000187:drug effects*; D014343:Trypan Blue / Q000494:pharmacology*
chemical_list: D016229:Amyloid beta-Peptides; D018621:PrPC Proteins; C009000:pontamine sky blue; D014343:Trypan Blue
keywords: Alzheimer disease; amyloid-beta (AB); drug discovery; fluorescence anisotropy; high-throughput screening (HTS); isothermal titration calorimetry (ITC); neurodegenerative disease; prion