TY - JOUR
T1 - Identification and characterization of novel candidate compounds targeting 6- and 7-transmembrane μ-opioid receptor isoforms
AU - Muralidharan, Arjun
AU - Samoshkin, Alexander
AU - Convertino, Marino
AU - Piltonen, Marjo Hannele
AU - Gris, Pavel
AU - Wang, Jian
AU - Jiang, Changyu
AU - Klares, Richard
AU - Linton, Alexander
AU - Ji, Ru Rong
AU - Maixner, William
AU - Dokholyan, Nikolay V.
AU - Mogil, Jeffrey S.
AU - Diatchenko, Luda
N1 - Funding Information:
A.M. was supported by the Ronald Melzack Fellowship in Chronic Pain Research awarded by the Louise and Alan Edwards Foundation. L.D., W.M. and N.V.D. were supported by National Institute on Drug Abuse STTR 1R41DA032293 grant. N.V.D. also acknowledge support from the National Institutes for Health grants 1R35 GM134864 and UL1 TR002014, and the Passan Foundation. J.S.M. was supported by grants from the Canadian Institutes for Health Research and the Natural Sciences and Engineering Council of Canada. L.D. was supported by a Pfizer Canada Professorship in Pain Research and the Canadian Excellence Research Chairs Program (CERC9).
Publisher Copyright:
© 2021 The British Pharmacological Society
PY - 2021/7
Y1 - 2021/7
N2 - Background and Purpose: The μ-opioid receptor (μ receptor) is the primary target for opioid analgesics. The 7-transmembrane (TM) and 6TM μ receptor isoforms mediate inhibitory and excitatory cellular effects. Here, we developed compounds selective for 6TM- or 7TM-μ receptors to further our understanding of the pharmacodynamic properties of μ receptors. Experimental Approach: We performed virtual screening of the ZINC Drug Now library of compounds using in silico 7TM- and 6TM-μ receptor structural models and identified potential compounds that are selective for 6TM- and/or 7TM-μ receptors. Subsequently, we characterized the most promising candidate compounds in functional in vitro studies using Be2C neuroblastoma transfected cells, behavioural in vivo pain assays using various knockout mice and in ex vivo electrophysiology studies. Key Results: Our virtual screen identified 30 potential candidate compounds. Subsequent functional in vitro cellular assays shortlisted four compounds (#5, 10, 11 and 25) that demonstrated 6TM- or 7TM-μ receptor-dependent NO release. In in vivo pain assays these compounds also produced dose-dependent hyperalgesic responses. Studies using mice that lack specific opioid receptors further established the μ receptor-dependent nature of identified novel ligands. Ex vivo electrophysiological studies on spontaneous excitatory postsynaptic currents in isolated spinal cord slices also validated the hyperalgesic properties of the most potent 6TM- (#10) and 7TM-μ receptor (#5) ligands. Conclusion and Implications: Our novel compounds represent a new class of ligands for μ receptors and will serve as valuable research tools to facilitate the development of opioids with significant analgesic efficacy and fewer side-effects.
AB - Background and Purpose: The μ-opioid receptor (μ receptor) is the primary target for opioid analgesics. The 7-transmembrane (TM) and 6TM μ receptor isoforms mediate inhibitory and excitatory cellular effects. Here, we developed compounds selective for 6TM- or 7TM-μ receptors to further our understanding of the pharmacodynamic properties of μ receptors. Experimental Approach: We performed virtual screening of the ZINC Drug Now library of compounds using in silico 7TM- and 6TM-μ receptor structural models and identified potential compounds that are selective for 6TM- and/or 7TM-μ receptors. Subsequently, we characterized the most promising candidate compounds in functional in vitro studies using Be2C neuroblastoma transfected cells, behavioural in vivo pain assays using various knockout mice and in ex vivo electrophysiology studies. Key Results: Our virtual screen identified 30 potential candidate compounds. Subsequent functional in vitro cellular assays shortlisted four compounds (#5, 10, 11 and 25) that demonstrated 6TM- or 7TM-μ receptor-dependent NO release. In in vivo pain assays these compounds also produced dose-dependent hyperalgesic responses. Studies using mice that lack specific opioid receptors further established the μ receptor-dependent nature of identified novel ligands. Ex vivo electrophysiological studies on spontaneous excitatory postsynaptic currents in isolated spinal cord slices also validated the hyperalgesic properties of the most potent 6TM- (#10) and 7TM-μ receptor (#5) ligands. Conclusion and Implications: Our novel compounds represent a new class of ligands for μ receptors and will serve as valuable research tools to facilitate the development of opioids with significant analgesic efficacy and fewer side-effects.
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U2 - 10.1111/bph.15463
DO - 10.1111/bph.15463
M3 - Article
C2 - 33782947
AN - SCOPUS:85105179960
VL - 178
SP - 2709
EP - 2726
JO - British Journal of Pharmacology
JF - British Journal of Pharmacology
SN - 0007-1188
IS - 13
ER -