title: Quantitative Signaling and Structure-Activity Analyses Demonstrate Functional Selectivity at the Nociceptin/Orphanin FQ Opioid Receptor.
abstract: Comprehensive studies that consolidate selective ligands, quantitative comparisons of G protein versus arrestin-2/3 coupling, together with structure-activity relationship models for G protein-coupled receptor (GPCR) systems are less commonly employed. Here we examine biased signaling at the nociceptin/orphanin FQ opioid receptor (NOPR), the most recently identified member of the opioid receptor family. Using real-time, live-cell assays, we identified the signaling profiles of several NOPR-selective ligands in upstream GPCR signaling (G protein and arrestin pathways) to determine their relative transduction coefficients and signaling bias. Complementing this analysis, we designed novel ligands on the basis of NOPR antagonist J-113,397 [(±)-1-[(3R*,4R*)-1-(cyclooctylmethyl)-3-(hydroxymethyl)-4-piperidinyl]-3-ethyl-1,3-dihydro-2H-benzimidazol-2-one] to explore structure-activity relationships. Our study shows that NOPR is capable of biased signaling, and further, the NOPR selective ligands MCOPPB [1-[1-(1-methylcyclooctyl)-4-piperidinyl]-2-(3R)-3-piperidinyl-1H-benzimidazole trihydrochloride] and NNC 63-0532 [8-(1-naphthalenylmethyl)-4-oxo-1-phenyl-1,3,8-triazaspiro[4.5]decane-3-acetic acid, methyl ester] are G protein-biased agonists. Additionally, minor structural modification of J-113,397 can dramatically shift signaling from antagonist to partial agonist activity. We explore these findings with in silico modeling of binding poses. This work is the first to demonstrate functional selectivity and identification of biased ligands at the nociceptin opioid receptor.
authors.affiliation: Department of Psychiatry (S.D.C.), Department of Anesthesiology, Basic Research Division (S.D.C., S.M.S., M.R.B.), Department of Anatomy and Neurobiology (M.R.B.), Washington University Pain Center (M.R.B.), Division of Biology and Biomedical Sciences Program in Neuroscience (S.M.S., M.R.B.), Washington University School of Medicine, St. Louis, Missouri; RTI International (S.W.M., H.A.N., F.I.C.), Research Triangle Park, North Carolina; and Vanderbilt University, Nashville, Tennessee (V.V.G.).
authors.forename: Steven D
authors.identifier: http://orcid.org/0000-0002-2530-2342
authors.initials: SD
authors.lastname: Chang
authors.affiliation: Department of Psychiatry (S.D.C.), Department of Anesthesiology, Basic Research Division (S.D.C., S.M.S., M.R.B.), Department of Anatomy and Neurobiology (M.R.B.), Washington University Pain Center (M.R.B.), Division of Biology and Biomedical Sciences Program in Neuroscience (S.M.S., M.R.B.), Washington University School of Medicine, St. Louis, Missouri; RTI International (S.W.M., H.A.N., F.I.C.), Research Triangle Park, North Carolina; and Vanderbilt University, Nashville, Tennessee (V.V.G.).
authors.forename: S Wayne
authors.identifier: http://orcid.org/0000-0003-0092-8178
authors.initials: SW
authors.lastname: Mascarella
authors.affiliation: Department of Psychiatry (S.D.C.), Department of Anesthesiology, Basic Research Division (S.D.C., S.M.S., M.R.B.), Department of Anatomy and Neurobiology (M.R.B.), Washington University Pain Center (M.R.B.), Division of Biology and Biomedical Sciences Program in Neuroscience (S.M.S., M.R.B.), Washington University School of Medicine, St. Louis, Missouri; RTI International (S.W.M., H.A.N., F.I.C.), Research Triangle Park, North Carolina; and Vanderbilt University, Nashville, Tennessee (V.V.G.).
authors.forename: Skylar M
authors.initials: SM
authors.lastname: Spangler
authors.affiliation: Department of Psychiatry (S.D.C.), Department of Anesthesiology, Basic Research Division (S.D.C., S.M.S., M.R.B.), Department of Anatomy and Neurobiology (M.R.B.), Washington University Pain Center (M.R.B.), Division of Biology and Biomedical Sciences Program in Neuroscience (S.M.S., M.R.B.), Washington University School of Medicine, St. Louis, Missouri; RTI International (S.W.M., H.A.N., F.I.C.), Research Triangle Park, North Carolina; and Vanderbilt University, Nashville, Tennessee (V.V.G.).
authors.forename: Vsevolod V
authors.identifier: http://orcid.org/0000-0002-3950-5351
authors.initials: VV
authors.lastname: Gurevich
authors.affiliation: Department of Psychiatry (S.D.C.), Department of Anesthesiology, Basic Research Division (S.D.C., S.M.S., M.R.B.), Department of Anatomy and Neurobiology (M.R.B.), Washington University Pain Center (M.R.B.), Division of Biology and Biomedical Sciences Program in Neuroscience (S.M.S., M.R.B.), Washington University School of Medicine, St. Louis, Missouri; RTI International (S.W.M., H.A.N., F.I.C.), Research Triangle Park, North Carolina; and Vanderbilt University, Nashville, Tennessee (V.V.G.).
authors.forename: Hernan A
authors.initials: HA
authors.lastname: Navarro
authors.affiliation: Department of Psychiatry (S.D.C.), Department of Anesthesiology, Basic Research Division (S.D.C., S.M.S., M.R.B.), Department of Anatomy and Neurobiology (M.R.B.), Washington University Pain Center (M.R.B.), Division of Biology and Biomedical Sciences Program in Neuroscience (S.M.S., M.R.B.), Washington University School of Medicine, St. Louis, Missouri; RTI International (S.W.M., H.A.N., F.I.C.), Research Triangle Park, North Carolina; and Vanderbilt University, Nashville, Tennessee (V.V.G.).
authors.forename: F Ivy
authors.identifier: http://orcid.org/0000-0001-9510-765X
authors.initials: FI
authors.lastname: Carroll
authors.affiliation: Department of Psychiatry (S.D.C.), Department of Anesthesiology, Basic Research Division (S.D.C., S.M.S., M.R.B.), Department of Anatomy and Neurobiology (M.R.B.), Washington University Pain Center (M.R.B.), Division of Biology and Biomedical Sciences Program in Neuroscience (S.M.S., M.R.B.), Washington University School of Medicine, St. Louis, Missouri; RTI International (S.W.M., H.A.N., F.I.C.), Research Triangle Park, North Carolina; and Vanderbilt University, Nashville, Tennessee (V.V.G.) bruchasm@wustl.edu.
authors.forename: Michael R
authors.initials: MR
authors.lastname: Bruchas
mesh_terms: D000085:Acetates / Q000737:chemistry / Q000494:pharmacology; D001562:Benzimidazoles / Q000737:chemistry / Q000494:pharmacology; D057809:HEK293 Cells; D006801:Humans; D009292:Narcotic Antagonists / Q000737:chemistry / Q000494:pharmacology*; D010880:Piperidines / Q000737:chemistry / Q000494:pharmacology; D011485:Protein Binding; D011957:Receptors, Opioid / Q000819:agonists / Q000737:chemistry / Q000378:metabolism*; D013141:Spiro Compounds / Q000737:chemistry / Q000494:pharmacology; D013329:Structure-Activity Relationship; D000094942:Nociceptin Receptor
chemical_list: C417686:(8-naphthalen-1-ylmethyl-4-oxo-1-phenyl-1,3,8-triaza-spiro(4.5)-dec-3-yl)acetic acid methyl ester; C528441:1-(1-(1-methylcyclooctyl)-4-piperidinyl)-2-((3R)-3-piperidinyl)-1H-benzimidazole; D000085:Acetates; D001562:Benzimidazoles; C402921:J 113397; D009292:Narcotic Antagonists; D010880:Piperidines; D011957:Receptors, Opioid; D013141:Spiro Compounds; D000094942:Nociceptin Receptor; C000722283:OPRL1 protein, human