Development of a human vasopressin V1a-receptor antagonist from an evolutionary-related insect neuropeptide

Maria Giulia Di Giglio, Markus Muttenthaler, Kasper Harpsøe, Zita Liutkeviciute, Peter Keov, Thomas Eder, Thomas Rattei, Sarah Arrowsmith, Susan Wray, Ales Marek, Tomas Elbert, Paul F Alewood, David E Gloriam, Christian W Gruber

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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 V1b receptors, 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.

Original languageEnglish
Article number41002
JournalScientific Reports
Volume7
Number of pages15
ISSN2045-2322
DOIs
Publication statusPublished - 1 Feb 2017

Keywords

  • Journal Article

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