title: Development of a human vasopressin V1a-receptor antagonist from an evolutionary-related insect neuropeptide.
abstract: Characterisation of G protein-coupled receptors (GPCR) relies on the availability of a toolbox of ligands that selectively modulate different functional states of the receptors. To uncover such molecules, we explored a unique strategy for ligand discovery that takes advantage of the evolutionary conservation of the 600-million-year-old oxytocin/vasopressin signalling system. We isolated the insect oxytocin/vasopressin orthologue inotocin from the black garden ant (Lasius niger), identified and cloned its cognate receptor and determined its pharmacological properties on the insect and human oxytocin/vasopressin receptors. Subsequently, we identified a functional dichotomy: inotocin activated the insect inotocin and the human vasopressin V1breceptors, but inhibited the human V1aR. Replacement of Arg8 of inotocin by D-Arg8 led to a potent, stable and competitive V1aR-antagonist ([D-Arg8]-inotocin) with a 3,000-fold binding selectivity for the human V1aR over the other three subtypes, OTR, V1bR and V2R. The Arg8/D-Arg8 ligand-pair was further investigated to gain novel insights into the oxytocin/vasopressin peptide-receptor interaction, which led to the identification of key residues of the receptors that are important for ligand functionality and selectivity. These observations could play an important role for development of oxytocin/vasopressin receptor modulators that would enable clear distinction of the physiological and pathological responses of the individual receptor subtypes.
authors.affiliation: Center for Physiology and Pharmacology, Medical University of Vienna, Schwarzspanierstrasse 17, 1090 Vienna, Austria.
authors.forename: Maria Giulia
authors.initials: MG
authors.lastname: Di Giglio
authors.affiliation: Institute for Molecular Bioscience, The University of Queensland, QLD 4072 Brisbane, Australia.
authors.forename: Markus
authors.initials: M
authors.lastname: Muttenthaler
authors.affiliation: Department of Drug Design and Pharmacology, University of Copenhagen, Jagtvej 162, 2100 Copenhagen, Denmark.
authors.forename: Kasper
authors.initials: K
authors.lastname: Harpsøe
authors.affiliation: Center for Physiology and Pharmacology, Medical University of Vienna, Schwarzspanierstrasse 17, 1090 Vienna, Austria.
authors.forename: Zita
authors.initials: Z
authors.lastname: Liutkeviciute
authors.affiliation: School of Biomedical Sciences, The University of Queensland, QLD 4072 Brisbane, Australia.
authors.forename: Peter
authors.initials: P
authors.lastname: Keov
authors.affiliation: IST Austria (Institute of Science and Technology), Am Campus 1, 3400 Klosterneuburg, Austria.|CUBE-Division of Computational Systems Biology, Department of Microbiology and Ecosystem Science, University of Vienna, Althanstrasse 14, 1090 Vienna, Austria.
authors.forename: Thomas
authors.initials: T
authors.lastname: Eder
authors.affiliation: CUBE-Division of Computational Systems Biology, Department of Microbiology and Ecosystem Science, University of Vienna, Althanstrasse 14, 1090 Vienna, Austria.
authors.forename: Thomas
authors.initials: T
authors.lastname: Rattei
authors.affiliation: Harris-Wellbeing Preterm Birth Research Centre, Department of Cellular and Molecular Physiology, Institute of Translational Medicine, University of Liverpool, L69 3BX, United Kingdom.
authors.forename: Sarah
authors.initials: S
authors.lastname: Arrowsmith
authors.affiliation: Harris-Wellbeing Preterm Birth Research Centre, Department of Cellular and Molecular Physiology, Institute of Translational Medicine, University of Liverpool, L69 3BX, United Kingdom.
authors.forename: Susan
authors.initials: S
authors.lastname: Wray
authors.affiliation: Laboratory of Radioisotopes, Institute of Organic Chemistry and Biochemistry CAS, Flemingovo nám. 2, CZ-16610 Prague 6, Czech Republic.
authors.forename: Ales
authors.initials: A
authors.lastname: Marek
authors.affiliation: Laboratory of Radioisotopes, Institute of Organic Chemistry and Biochemistry CAS, Flemingovo nám. 2, CZ-16610 Prague 6, Czech Republic.
authors.forename: Tomas
authors.initials: T
authors.lastname: Elbert
authors.affiliation: Institute for Molecular Bioscience, The University of Queensland, QLD 4072 Brisbane, Australia.
authors.forename: Paul F
authors.initials: PF
authors.lastname: Alewood
authors.affiliation: Department of Drug Design and Pharmacology, University of Copenhagen, Jagtvej 162, 2100 Copenhagen, Denmark.
authors.forename: David E
authors.initials: DE
authors.lastname: Gloriam
authors.affiliation: Center for Physiology and Pharmacology, Medical University of Vienna, Schwarzspanierstrasse 17, 1090 Vienna, Austria.|School of Biomedical Sciences, The University of Queensland, QLD 4072 Brisbane, Australia.
authors.forename: Christian W
authors.initials: CW
authors.lastname: Gruber
mesh_terms: D019943:Amino Acid Substitution; D000818:Animals; D065092:Antidiuretic Hormone Receptor Antagonists / Q000302:isolation & purification / Q000378:metabolism*; D001000:Ants; D004252:DNA Mutational Analysis; D006801:Humans; D009479:Neuropeptides / Q000235:genetics / Q000302:isolation & purification / Q000378:metabolism*; D011485:Protein Binding; D017483:Receptors, Vasopressin / Q000819:agonists*; D011994:Recombinant Proteins / Q000235:genetics / Q000302:isolation & purification / Q000378:metabolism
chemical_list: D065092:Antidiuretic Hormone Receptor Antagonists; D009479:Neuropeptides; D017483:Receptors, Vasopressin; D011994:Recombinant Proteins