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Drakopoulos A, Koszegi Z, Seier K, Hübner H, Maurel D, Sounier R, Granier S, Gmeiner P, Calebiro D, Decker M. Design, Synthesis, and Characterization of New δ Opioid Receptor-Selective Fluorescent Probes and Applications in Single-Molecule Microscopy of Wild-Type Receptors. J Med Chem 2024. [PMID: 39044606 DOI: 10.1021/acs.jmedchem.4c00627] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 07/25/2024]
Abstract
The delta opioid receptor (δOR or DOR) is a G protein-coupled receptor (GPCR) showing a promising profile as a drug target for nociception and analgesia. Herein, we design and synthesize new fluorescent antagonist probes with high δOR selectivity that are ideally suited for single-molecule microscopy (SMM) applications in unmodified, untagged receptors. Using our new probes, we investigated wild-type δOR localization and mobility at low physiological receptor densities for the first time. Furthermore, we investigate the potential formation of δOR homodimers, as such a receptor organization might exhibit distinct pharmacological activity, potentially paving the way for innovative pharmacological therapies. Our findings indicate that the majority of δORs labeled with these probes exist as freely diffusing monomers on the cell surface in a simple cell model. This discovery advances our understanding of OR behavior and offers potential implications for future therapeutic research.
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Affiliation(s)
- Antonios Drakopoulos
- Pharmazeutische und Medizinische Chemie, Institut für Pharmazie und Lebensmittelchemie, Julius-Maximilians-Universität (JMU) Würzburg, Am Hubland, 97074 Würzburg, Germany
| | - Zsombor Koszegi
- Institute of Metabolism and Systems Research, University of Birmingham, B15 2TT Birmingham, U.K
- Centre of Membrane Proteins and Receptors, Universities of Birmingham and Nottingham, B15 2TT Birmingham, U.K
| | - Kerstin Seier
- Institute of Pharmacology and Toxicology, Julius-Maximilians University of Würzburg, Versbacher Strasse 9, 97078 Würzburg, Germany
| | - Harald Hübner
- Chair of Pharmaceutical Chemistry, Department of Chemistry and Pharmacy, Friedrich-Alexander University of Erlangen-Nürnberg, 91058 Erlangen, Germany
| | - Damien Maurel
- Institut de Génomique Fonctionnelle, CNRS, INSERM, Université de Montpellier, 34094 Cedex 5 Montpellier, France
| | - Rémy Sounier
- Institut de Génomique Fonctionnelle, CNRS, INSERM, Université de Montpellier, 34094 Cedex 5 Montpellier, France
| | - Sébastien Granier
- Institut de Génomique Fonctionnelle, CNRS, INSERM, Université de Montpellier, 34094 Cedex 5 Montpellier, France
| | - Peter Gmeiner
- Chair of Pharmaceutical Chemistry, Department of Chemistry and Pharmacy, Friedrich-Alexander University of Erlangen-Nürnberg, 91058 Erlangen, Germany
| | - Davide Calebiro
- Institute of Metabolism and Systems Research, University of Birmingham, B15 2TT Birmingham, U.K
- Centre of Membrane Proteins and Receptors, Universities of Birmingham and Nottingham, B15 2TT Birmingham, U.K
| | - Michael Decker
- Pharmazeutische und Medizinische Chemie, Institut für Pharmazie und Lebensmittelchemie, Julius-Maximilians-Universität (JMU) Würzburg, Am Hubland, 97074 Würzburg, Germany
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2
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Coutens B, Ingram SL. Key differences in regulation of opioid receptors localized to presynaptic terminals compared to somas: Relevance for novel therapeutics. Neuropharmacology 2023; 226:109408. [PMID: 36584882 PMCID: PMC9898207 DOI: 10.1016/j.neuropharm.2022.109408] [Citation(s) in RCA: 3] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/12/2022] [Revised: 12/05/2022] [Accepted: 12/27/2022] [Indexed: 12/29/2022]
Abstract
Opioid receptors are G protein-coupled receptors (GPCRs) that regulate activity within peripheral, subcortical and cortical circuits involved in pain, reward, and aversion processing. Opioid receptors are expressed in both presynaptic terminals where they inhibit neurotransmitter release and postsynaptic locations where they act to hyperpolarize neurons and reduce activity. Agonist activation of postsynaptic receptors at the plasma membrane signal via ion channels or cytoplasmic second messengers. Agonist binding initiates regulatory processes that include phosphorylation by G protein receptor kinases (GRKs) and recruitment of beta-arrestins that desensitize and internalize the receptors. Opioid receptors also couple to effectors from endosomes activating intracellular enzymes and kinases. In contrast to postsynaptic opioid receptors, receptors localized to presynaptic terminals are resistant to desensitization such that there is no loss of signaling in the continuous presence of opioids over the same time scale. Thus, the balance of opioid signaling in circuits expressing pre- and postsynaptic opioid receptors is shifted toward inhibition of presynaptic neurotransmitter release during continuous opioid exposure. The functional implication of this shift is not often acknowledged in behavioral studies. This review covers what is currently understood about regulation of opioid/nociceptin receptors, with an emphasis on opioid receptor signaling in pain and reward circuits. Importantly, the review covers regulation of presynaptic receptors and the critical gaps in understanding this area, as well as the opportunities to further understand opioid signaling in brain circuits. This article is part of the Special Issue on "Opioid-induced changes in addiction and pain circuits".
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Affiliation(s)
- Basile Coutens
- Department of Anesthesiology, University of Colorado Anschutz Medical Campus, Aurora, CO, 80045, USA
| | - Susan L Ingram
- Department of Anesthesiology, University of Colorado Anschutz Medical Campus, Aurora, CO, 80045, USA.
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Quirion B, Beaulieu C, Côté L, Parent JL, Gendron L. Distribution of delta and mu opioid receptor mRNA in rodent dorsal root ganglia neurons. Eur J Neurosci 2022; 56:4031-4044. [PMID: 35674691 PMCID: PMC9543299 DOI: 10.1111/ejn.15733] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/15/2021] [Revised: 05/24/2022] [Accepted: 06/02/2022] [Indexed: 12/01/2022]
Abstract
Primary afferents are responsible for transmitting signals produced by noxious stimuli from the periphery to the spinal cord. Mu and delta opioid receptors (MOP and DOP) have analgesic properties and are highly expressed in dorsal root ganglia (DRG) neurons. In humans, spinal DOP is almost exclusively located on central terminals of DRG neurons, whereas in rodents, it is expressed both on presynaptic terminals and spinal neurons. In this study, we aimed to assess the distribution of MOP and DOP in the DRGs of mice and rats. Using in situ hybridization and immunofluorescence, we visualized MOP and DOP mRNA together with various neuronal markers. In rats and mice, we show that both receptors are expressed, albeit to different extents, in all types of neurons, namely, large and medium myelinated neurons (NF200-positive), small nonpeptidergic (IB4- or P2X3R-positive) and peptidergic C fibres (Tac1-positive). Overall, DOP mRNA was found to be mainly expressed in large and medium myelinated neurons, whereas MOP mRNA was mainly found in C fibres. The distribution of MOP and DOP, however, slightly differs between rats and mice, with a higher proportion of small nonpeptidergic C fibres expressing DOP mRNA in mice than in rats. We further found that neither morphine nor inflammation affected the distribution of the receptor mRNA. Because of their location, our results confirm that MOP and DOP have the potential to alleviate similar types of pain and that this effect could slightly differ between species.
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Affiliation(s)
- Béatrice Quirion
- Département de Pharmacologie-Physiologie, Université de Sherbrooke, Sherbrooke, Québec, Canada.,Institut de Pharmacologie de Sherbrooke, Centre de Recherche du CHUS, Faculté de Médecine et des Sciences de la Santé, Université de Sherbrooke, Sherbrooke, Québec, Canada
| | - Claudie Beaulieu
- Département de Pharmacologie-Physiologie, Université de Sherbrooke, Sherbrooke, Québec, Canada.,Institut de Pharmacologie de Sherbrooke, Centre de Recherche du CHUS, Faculté de Médecine et des Sciences de la Santé, Université de Sherbrooke, Sherbrooke, Québec, Canada
| | - Laurie Côté
- Département de Pharmacologie-Physiologie, Université de Sherbrooke, Sherbrooke, Québec, Canada.,Département de Médecine, Université de Sherbrooke, Sherbrooke, Québec, Canada.,Institut de Pharmacologie de Sherbrooke, Centre de Recherche du CHUS, Faculté de Médecine et des Sciences de la Santé, Université de Sherbrooke, Sherbrooke, Québec, Canada
| | - Jean-Luc Parent
- Département de Médecine, Université de Sherbrooke, Sherbrooke, Québec, Canada.,Institut de Pharmacologie de Sherbrooke, Centre de Recherche du CHUS, Faculté de Médecine et des Sciences de la Santé, Université de Sherbrooke, Sherbrooke, Québec, Canada
| | - Louis Gendron
- Département de Pharmacologie-Physiologie, Université de Sherbrooke, Sherbrooke, Québec, Canada.,Institut de Pharmacologie de Sherbrooke, Centre de Recherche du CHUS, Faculté de Médecine et des Sciences de la Santé, Université de Sherbrooke, Sherbrooke, Québec, Canada.,Quebec Pain Research Network
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Abstract
The chronification of pain can be attributed to changes in membrane receptors and channels underlying neuronal plasticity and signal transduction largely within nociceptive neurons that initiate and maintain pathological pain states. These proteins are subject to dynamic modification by posttranslational modifications, creating a code that controls protein function in time and space. Phosphorylation is an important posttranslational modification that affects ∼30% of proteins in vivo. Increased phosphorylation of various nociceptive ion channels and of their modulators underlies sensitization of different pain states. Cyclin-dependent kinases are proline-directed serine/threonine kinases that impact various biological and cellular systems. Cyclin-dependent kinase 5 (Cdk5), one member of this kinase family, and its activators p35 and p39 are expressed in spinal nerves, dorsal root ganglia, and the dorsal horn of the spinal cord. In neuropathic pain conditions, expression and/or activity of Cdk5 is increased, implicating Cdk5 in nociception. Experimental evidence suggests that Cdk5 is regulated through its own phosphorylation, through increasing p35's interaction with Cdk5, and through cleavage of p35 into p25. This narrative review discusses the molecular mechanisms of Cdk5-mediated regulation of target proteins involved in neuropathic pain. We focus on Cdk5 substrates that have been linked to nociceptive pathways, including channels (eg, transient receptor potential cation channel and voltage-gated calcium channel), proteins involved in neurotransmitter release (eg, synaptophysin and collapsin response mediator protein 2), and receptors (eg, glutamate, purinergic, and opioid). By altering the phosphoregulatory "set point" of proteins involved in pain signaling, Cdk5 thus appears to be an attractive target for treating neuropathic pain conditions.
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Quirion B, Bergeron F, Blais V, Gendron L. The Delta-Opioid Receptor; a Target for the Treatment of Pain. Front Mol Neurosci 2020; 13:52. [PMID: 32431594 PMCID: PMC7214757 DOI: 10.3389/fnmol.2020.00052] [Citation(s) in RCA: 35] [Impact Index Per Article: 8.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/04/2019] [Accepted: 03/13/2020] [Indexed: 12/15/2022] Open
Abstract
Nowadays, pain represents one of the most important societal burdens. Current treatments are, however, too often ineffective and/or accompanied by debilitating unwanted effects for patients dealing with chronic pain. Indeed, the prototypical opioid morphine, as many other strong analgesics, shows harmful unwanted effects including respiratory depression and constipation, and also produces tolerance, physical dependence, and addiction. The urgency to develop novel treatments against pain while minimizing adverse effects is therefore crucial. Over the years, the delta-opioid receptor (DOP) has emerged as a promising target for the development of new pain therapies. Indeed, targeting DOP to treat chronic pain represents a timely alternative to existing drugs, given the weak unwanted effects spectrum of DOP agonists. Here, we review the current knowledge supporting a role for DOP and its agonists for the treatment of pain. More specifically, we will focus on the cellular and subcellular localization of DOP in the nervous system. We will also discuss in further detail the molecular and cellular mechanisms involved in controlling the cellular trafficking of DOP, known to differ significantly from most G protein-coupled receptors. This review article will allow a better understanding of how DOP represents a promising target to develop new treatments for pain management as well as where we stand as of our ability to control its cellular trafficking and cell surface expression.
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Affiliation(s)
- Béatrice Quirion
- Faculté de Médecine et des Sciences de la Santé, Département de Pharmacologie-Physiologie, Institut de Pharmacologie de Sherbrooke, Centre de Recherche du Centre Hospitalier Universitaire de Sherbrooke, Université de Sherbrooke, Sherbrooke, QC, Canada
| | - Francis Bergeron
- Faculté de Médecine et des Sciences de la Santé, Département de Pharmacologie-Physiologie, Institut de Pharmacologie de Sherbrooke, Centre de Recherche du Centre Hospitalier Universitaire de Sherbrooke, Université de Sherbrooke, Sherbrooke, QC, Canada
| | - Véronique Blais
- Faculté de Médecine et des Sciences de la Santé, Département de Pharmacologie-Physiologie, Institut de Pharmacologie de Sherbrooke, Centre de Recherche du Centre Hospitalier Universitaire de Sherbrooke, Université de Sherbrooke, Sherbrooke, QC, Canada
| | - Louis Gendron
- Faculté de Médecine et des Sciences de la Santé, Département de Pharmacologie-Physiologie, Institut de Pharmacologie de Sherbrooke, Centre de Recherche du Centre Hospitalier Universitaire de Sherbrooke, Université de Sherbrooke, Sherbrooke, QC, Canada
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6
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Tiwari V, He SQ, Huang Q, Liang L, Yang F, Chen Z, Tiwari V, Fujita W, Devi LA, Dong X, Guan Y, Raja SN. Activation of µ-δ opioid receptor heteromers inhibits neuropathic pain behavior in rodents. Pain 2020; 161:842-855. [PMID: 31815916 PMCID: PMC7085422 DOI: 10.1097/j.pain.0000000000001768] [Citation(s) in RCA: 39] [Impact Index Per Article: 9.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/12/2022]
Abstract
Several reports support the idea that µ- and δ-opioid receptors (ORs) may exist as heterodimers in brain regions involved in pain signaling. The unique pharmacology of these heteromers may present a novel analgesic target. However, the role of µ-δ heteromers in sensory neurons involved in pain and opioid analgesia remains unclear, particularly during neuropathic pain. We examined the effects of spinal nerve injury on µ-δ heteromer expression in dorsal root ganglion (DRG) neurons and the effects of a µ-δ heteromer-targeting agonist, CYM51010, on neuropathic pain behavior in rats and mice. An L5 spinal nerve ligation (SNL) in rats significantly decreased µ-δ heteromer expression in L5 DRG but increased heteromer levels in uninjured L4 DRG. Importantly, in SNL rats, subcutaneous injection of CYM51010 inhibited mechanical hypersensitivity in a dose-related manner (EC50: 1.09 mg/kg) and also reversed heat hyperalgesia and attenuated ongoing pain (2 mg/kg, subcutaneously). HEK-293T cell surface-labeled with µ- and δ-ORs internalized both receptors after exposure to CYM51010. By contrast, in cells transfected with µ-OR alone, CYM51010 was significantly less effective at inducing receptor internalization. Electrophysiologic studies showed that CYM51010 inhibited the C-component and windup phenomenon in spinal wide dynamic range neurons of SNL rats. The pain inhibitory effects of CYM51010 persisted in morphine-tolerant rats but was markedly attenuated in µ-OR knockout mice. Our studies show that spinal nerve injury may increase µ-δ heterodimerization in uninjured DRG neurons, and that µ-δ heteromers may be a potential therapeutic target for relieving neuropathic pain, even under conditions of morphine tolerance.
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Affiliation(s)
- Vinod Tiwari
- Department of Anesthesiology and Critical Care Medicine, the Johns Hopkins University, School of Medicine, Baltimore, Maryland, 21205, USA
| | - Shao-Qiu He
- Department of Anesthesiology and Critical Care Medicine, the Johns Hopkins University, School of Medicine, Baltimore, Maryland, 21205, USA
| | - Qian Huang
- Department of Anesthesiology and Critical Care Medicine, the Johns Hopkins University, School of Medicine, Baltimore, Maryland, 21205, USA
| | - Lingli Liang
- Department of Anesthesiology and Critical Care Medicine, the Johns Hopkins University, School of Medicine, Baltimore, Maryland, 21205, USA
| | - Fei Yang
- Department of Anesthesiology and Critical Care Medicine, the Johns Hopkins University, School of Medicine, Baltimore, Maryland, 21205, USA
| | - Zhiyong Chen
- Department of Anesthesiology and Critical Care Medicine, the Johns Hopkins University, School of Medicine, Baltimore, Maryland, 21205, USA
| | - Vineeta Tiwari
- Department of Anesthesiology and Critical Care Medicine, the Johns Hopkins University, School of Medicine, Baltimore, Maryland, 21205, USA
| | - Wakako Fujita
- Department of Pharmacological Sciences, Icahn School of Medicine at Mount Sinai, New York, NY, 10029, USA
| | - Lakshmi A. Devi
- Department of Pharmacological Sciences, Icahn School of Medicine at Mount Sinai, New York, NY, 10029, USA
| | - Xinzhong Dong
- The Solomon H. Snyder Department of Neuroscience, Center for Sensory Biology, the Johns Hopkins University, School of Medicine, Baltimore, Maryland, 21205, USA
- Howard Hughes Medical Institute, the Johns Hopkins University, School of Medicine, Baltimore, Maryland, 21205, USA
| | - Yun Guan
- Department of Anesthesiology and Critical Care Medicine, the Johns Hopkins University, School of Medicine, Baltimore, Maryland, 21205, USA
- Department of Neurological Surgery, the Johns Hopkins University, School of Medicine, Baltimore, MD, USA
| | - Srinivasa N. Raja
- Department of Anesthesiology and Critical Care Medicine, the Johns Hopkins University, School of Medicine, Baltimore, Maryland, 21205, USA
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Berthiaume S, Abdallah K, Blais V, Gendron L. Alleviating pain with delta opioid receptor agonists: evidence from experimental models. J Neural Transm (Vienna) 2020; 127:661-672. [PMID: 32189076 DOI: 10.1007/s00702-020-02172-4] [Citation(s) in RCA: 9] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/19/2019] [Accepted: 03/06/2020] [Indexed: 12/11/2022]
Abstract
The use of opioids for the relief of pain and headache disorders has been studied for years. Nowadays, particularly because of its ability to produce analgesia in various pain models, delta opioid receptor (DOPr) emerges as a promising target for the development of new pain therapies. Indeed, their potential to avoid the unwanted effects commonly observed with clinically used opioids acting at the mu opioid receptor (MOPr) suggests that DOPr agonists could be a therapeutic option. In this review, we discuss the use of opioids in the management of pain in addition to describing the evidence of the analgesic potency of DOPr agonists in animal models.
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Affiliation(s)
- Sophie Berthiaume
- Département de Pharmacologie-Physiologie, Institut de Pharmacologie de Sherbrooke, Centre de Recherche du Centre Hospitalier Universitaire de Sherbrooke, Faculté de médecine et des sciences de la santé, Université de Sherbrooke, 3001, 12th Avenue North, Sherbrooke, QC, J1H 5N4, Canada
| | - Khaled Abdallah
- Département de Pharmacologie-Physiologie, Institut de Pharmacologie de Sherbrooke, Centre de Recherche du Centre Hospitalier Universitaire de Sherbrooke, Faculté de médecine et des sciences de la santé, Université de Sherbrooke, 3001, 12th Avenue North, Sherbrooke, QC, J1H 5N4, Canada
| | - Véronique Blais
- Département de Pharmacologie-Physiologie, Institut de Pharmacologie de Sherbrooke, Centre de Recherche du Centre Hospitalier Universitaire de Sherbrooke, Faculté de médecine et des sciences de la santé, Université de Sherbrooke, 3001, 12th Avenue North, Sherbrooke, QC, J1H 5N4, Canada
| | - Louis Gendron
- Département de Pharmacologie-Physiologie, Institut de Pharmacologie de Sherbrooke, Centre de Recherche du Centre Hospitalier Universitaire de Sherbrooke, Faculté de médecine et des sciences de la santé, Université de Sherbrooke, 3001, 12th Avenue North, Sherbrooke, QC, J1H 5N4, Canada.
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8
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Pasquinucci L, Turnaturi R, Montenegro L, Caraci F, Chiechio S, Parenti C. Simultaneous targeting of MOR/DOR: A useful strategy for inflammatory pain modulation. Eur J Pharmacol 2019; 847:97-102. [PMID: 30690004 DOI: 10.1016/j.ejphar.2019.01.031] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/13/2018] [Revised: 01/18/2019] [Accepted: 01/18/2019] [Indexed: 02/03/2023]
Abstract
Development of new analgesics endowed with mu/delta opioid receptor (MOR/DOR) activity represents a promising alternative to MOR selective compounds because of their better therapeutic and tolerability profile. Lately, we have synthetized the MOR/DOR agonist LP2 that showed a long lasting antinociceptive activity in the tail flick test, an acute pain model. Here, we investigate whether LP2 is also effective in the mouse formalin test, a model of inflammatory pain sustained by mechanisms of central sensitization. Moreover, we evaluated a possible peripheral component of LP2 analgesic activity. Different doses of LP2 were tested after either intraperitoneal (i.p.) or intraplantar (i.pl.) administration. LP2 (0.75-1.00 mg/kg, i.p.), dose-dependently, counteracted both phases of the formalin test after i.p. administration. The analgesic activity of LP2 (0.75-1.00 mg/kg) was completely blocked by a pretreatment with the opioid antagonist naloxone (3 mg/kg, i.p.). Differently, the pretreatment with naloxone methiodide (5 mg/kg, i.p.), a peripherally restricted opioid antagonist, completely blocked the lower analgesic dose of LP2 (0.75 mg/kg) but only partially relieved the antinociceptive effects of LP2 at the dose of 1.00 mg/kg, thus revealing a peripheral analgesic component of LP2. I.pl. injections of LP2 (10-20 μg/10 μl) were also performed to investigate a possible effect of LP2 on peripheral nerve terminals. Nociceptive sensitization, which occur both at peripheral and central level, is a fundamental step for pain chronicization, thus LP2 is a promising drug for pain conditions characterized by nociceptive sensitization.
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Affiliation(s)
- Lorella Pasquinucci
- Department of Drug Sciences, Medicinal Chemistry Section, University of Catania, Viale A. Doria 6, 95125 Catania, Italy
| | - Rita Turnaturi
- Department of Drug Sciences, Medicinal Chemistry Section, University of Catania, Viale A. Doria 6, 95125 Catania, Italy.
| | - Lucia Montenegro
- Department of Drug Sciences, Pharmaceutical Technology Section, University of Catania, Viale A. Doria 6, 95125 Catania, Italy
| | - Filippo Caraci
- Department of Drug Sciences, Pharmacology and Toxicology Section, University of Catania, Viale A. Doria 6, 95125 Catania, Italy; Oasi Research Institute-IRCCS, Troina, Italy
| | - Santina Chiechio
- Department of Drug Sciences, Pharmacology and Toxicology Section, University of Catania, Viale A. Doria 6, 95125 Catania, Italy; Oasi Research Institute-IRCCS, Troina, Italy
| | - Carmela Parenti
- Department of Drug Sciences, Pharmacology and Toxicology Section, University of Catania, Viale A. Doria 6, 95125 Catania, Italy
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9
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Alternative Splicing of the Delta-Opioid Receptor Gene Suggests Existence of New Functional Isoforms. Mol Neurobiol 2018; 56:2855-2869. [PMID: 30066306 DOI: 10.1007/s12035-018-1253-z] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/25/2018] [Accepted: 07/17/2018] [Indexed: 12/26/2022]
Abstract
The delta-opioid receptor (DOPr) participates in mediating the effects of opioid analgesics. However, no selective agonists have entered clinical care despite potential to ameliorate many neurological and psychiatric disorders. In an effort to address the drug development challenges, the functional contribution of receptor isoforms created by alternative splicing of the three-exonic coding gene, OPRD1, has been overlooked. We report that the gene is transcriptionally more diverse than previously demonstrated, producing novel protein isoforms in humans and mice. We provide support for the functional relevance of splice variants through context-dependent expression profiling (tissues, disease model) and conservation of the transcriptional landscape in closely related vertebrates. The conserved alternative transcriptional events have two distinct patterns. First, cassette exon inclusions between exons 1 and 2 interrupt the reading frame, producing truncated receptor fragments comprising only the first transmembrane (TM) domain, despite the lack of exact exon orthologues between distant species. Second, a novel promoter and transcriptional start site upstream of exon 2 produces a transcript of an N-terminally truncated 6TM isoform. However, a fundamental difference in the exonic landscaping as well as translation and translation products poses limits for modelling the human DOPr receptor system in mice.
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Dietis N, Niwa H, Tose R, McDonald J, Ruggieri V, Filaferro M, Vitale G, Micheli L, Ghelardini C, Salvadori S, Calo G, Guerrini R, Rowbotham DJ, Lambert DG. In vitro and in vivo characterization of the bifunctional μ and δ opioid receptor ligand UFP-505. Br J Pharmacol 2018; 175:2881-2896. [PMID: 29524334 PMCID: PMC6016625 DOI: 10.1111/bph.14199] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/27/2017] [Revised: 02/21/2018] [Accepted: 02/22/2018] [Indexed: 12/28/2022] Open
Abstract
BACKGROUND AND PURPOSE Targeting more than one opioid receptor type simultaneously may have analgesic advantages in reducing side-effects. We have evaluated the mixed μ opioid receptor agonist/ δ opioid receptor antagonist UFP-505 in vitro and in vivo. EXPERIMENTAL APPROACH We measured receptor density and function in single μ, δ and μ /δ receptor double expression systems. GTPγ35 S binding, cAMP formation and arrestin recruitment were measured. Antinociceptive activity was measured in vivo using tail withdrawal and paw pressure tests following acute and chronic treatment. In some experiments, we collected tissues to measure receptor densities. KEY RESULTS UFP-505 bound to μ receptors with full agonist activity and to δ receptors as a low efficacy partial agonist At μ, but not δ receptors, UFP-505 binding recruited arrestin. Unlike morphine, UFP-505 treatment internalized μ receptors and there was some evidence for internalization of δ receptors. Similar data were obtained in a μ /δ receptor double expression system. In rats, acute UFP-505 or morphine, injected intrathecally, was antinociceptive. In tissues harvested from these experiments, μ and δ receptor density was decreased after UFP-505 but not morphine treatment, in agreement with in vitro data. Both morphine and UFP-505 induced significant tolerance. CONCLUSIONS AND IMPLICATIONS In this study, UFP-505 behaved as a full agonist at μ receptors with variable activity at δ receptors. This bifunctional compound was antinociceptive in rats after intrathecal administration. In this model, dual targeting provided no advantages in terms of tolerance liability. LINKED ARTICLES This article is part of a themed section on Emerging Areas of Opioid Pharmacology. To view the other articles in this section visit http://onlinelibrary.wiley.com/doi/10.1111/bph.v175.14/issuetoc.
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Affiliation(s)
- N Dietis
- Department of Cardiovascular SciencesUniversity of Leicester, Division of Anaesthesia, Critical Care and Pain Management, Leicester Royal InfirmaryLeicesterUK
| | - H Niwa
- Department of Cardiovascular SciencesUniversity of Leicester, Division of Anaesthesia, Critical Care and Pain Management, Leicester Royal InfirmaryLeicesterUK
| | - R Tose
- Department of Cardiovascular SciencesUniversity of Leicester, Division of Anaesthesia, Critical Care and Pain Management, Leicester Royal InfirmaryLeicesterUK
| | - J McDonald
- Department of Cardiovascular SciencesUniversity of Leicester, Division of Anaesthesia, Critical Care and Pain Management, Leicester Royal InfirmaryLeicesterUK
| | - V Ruggieri
- Department of Oncology Haematology and Respiratory DiseasesUniversity of Modena and Reggio EmiliaModenaItaly
| | - M Filaferro
- Department of Biomedical, Metabolic and Neuro‐SciencesUniversity of Modena and Reggio EmiliaModenaItaly
| | - G Vitale
- Section of Pharmacology, Department of Life SciencesUniversity of Modena and Reggio EmiliaModenaItaly
| | - L Micheli
- Department of Preclinical and Clinical PharmacologyUniversity of FlorenceFlorenceItaly
| | - C Ghelardini
- Department of Preclinical and Clinical PharmacologyUniversity of FlorenceFlorenceItaly
| | - S Salvadori
- Department of Experimental and Clinical Medicine, Section of PharmacologyUniversity of FerraraFerraraItaly
| | - G Calo
- Department of Experimental and Clinical Medicine, Section of PharmacologyUniversity of FerraraFerraraItaly
| | - R Guerrini
- Department of Pharmaceutical SciencesUniversity of FerraraFerraraItaly
| | - D J Rowbotham
- Department of Health SciencesUniversity of Leicester, Division of Anaesthesia, Critical Care and Pain Management, Leicester Royal InfirmaryLeicesterUK
| | - D G Lambert
- Department of Cardiovascular SciencesUniversity of Leicester, Division of Anaesthesia, Critical Care and Pain Management, Leicester Royal InfirmaryLeicesterUK
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11
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Bao F, Li CL, Chen XQ, Lu YJ, Bao L, Zhang X. Clinical opioids differentially induce co-internalization of μ- and δ-opioid receptors. Mol Pain 2018; 14:1744806918769492. [PMID: 29587571 PMCID: PMC5898661 DOI: 10.1177/1744806918769492] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/17/2022] Open
Abstract
Opioid receptors play an important role in mediating the spinal analgesia. The μ-opioid receptor is the major target of opioid drugs widely used in clinics. However, the regulatory mechanisms of analgesic effect and tolerance for clinical μ-opioid receptor-targeting opioids remain to be fully investigated. Previous studies showed the interaction of δ-opioid receptor with μ-opioid receptor to form the μ-opioid receptor/δ-opioid receptor heteromers that could be processed in the degradation pathway after δ-opioid receptor agonist treatment. Here, we showed that clinical μ-opioid receptor-targeting opioids, morphine, fentanyl, and methadone, but not tramadol, caused μ-opioid receptor co-internalization with δ-opioid receptors in both transfected human embryonic kidney 293 cells and primary sensory neurons. Prolonged treatment of morphine led to μ-opioid receptor co-degradation with δ-opioid receptors. Furthermore, fentanyl and methadone, but not tramadol, induced the drug tolerance similar to morphine. Thus, the clinical μ-opioid receptor-targeting opioids including morphine, fentanyl, and methadone induce μ-opioid receptor co-internalization with δ-opioid receptors, which may be involved in the analgesic tolerance of these opioids.
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Affiliation(s)
- Fenghua Bao
- 1 Institute of Neuroscience and State Key Laboratory of Neuroscience, CAS Center for Excellence in Brain Science and Intelligence Technology, Chinese Academy of Sciences, Shanghai, China.,2 University of Chinese Academy of Sciences, Shanghai, China
| | - Chang-Lin Li
- 1 Institute of Neuroscience and State Key Laboratory of Neuroscience, CAS Center for Excellence in Brain Science and Intelligence Technology, Chinese Academy of Sciences, Shanghai, China.,2 University of Chinese Academy of Sciences, Shanghai, China.,3 Shanghai Clinical Research Center, Chinese Academy of Sciences/XuHui Central Hospital, Shanghai, China
| | - Xu-Qiao Chen
- 4 State Key Laboratory of Cell Biology, CAS Center for Excellence in Molecular Cell Science, Shanghai Institute of Biochemistry and Cell Biology, Chinese Academy of Sciences, Shanghai, China
| | - Ying-Jin Lu
- 1 Institute of Neuroscience and State Key Laboratory of Neuroscience, CAS Center for Excellence in Brain Science and Intelligence Technology, Chinese Academy of Sciences, Shanghai, China.,2 University of Chinese Academy of Sciences, Shanghai, China.,3 Shanghai Clinical Research Center, Chinese Academy of Sciences/XuHui Central Hospital, Shanghai, China
| | - Lan Bao
- 4 State Key Laboratory of Cell Biology, CAS Center for Excellence in Molecular Cell Science, Shanghai Institute of Biochemistry and Cell Biology, Chinese Academy of Sciences, Shanghai, China.,5 School of Life Science and Technology, ShanghaiTech University, Shanghai, China
| | - Xu Zhang
- 1 Institute of Neuroscience and State Key Laboratory of Neuroscience, CAS Center for Excellence in Brain Science and Intelligence Technology, Chinese Academy of Sciences, Shanghai, China.,2 University of Chinese Academy of Sciences, Shanghai, China.,5 School of Life Science and Technology, ShanghaiTech University, Shanghai, China
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12
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Abstract
Nowadays, the delta opioid receptor (DOPr) represents a promising target for the treatment of chronic pain and emotional disorders. Despite the fact that they produce limited antinociceptive effects in healthy animals and in most acute pain models, DOPr agonists have shown efficacy in various chronic pain models. In this chapter, we review the progresses that have been made over the last decades in understanding the role played by DOPr in the control of pain. More specifically, the distribution of DOPr within the central nervous system and along pain pathways is presented. We also summarize the literature supporting a role for DOPr in acute, tonic, and chronic pain models, as well as the mechanisms regulating its activity under specific conditions. Finally, novel compounds that have make their way to clinical trials are discussed.
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Affiliation(s)
- Khaled Abdallah
- Département de pharmacologie-physiologie, Université de Sherbrooke, Sherbrooke, QC, Canada
- Institut de pharmacologie de Sherbrooke, Université de Sherbrooke, Sherbrooke, QC, Canada
- Faculté de médecine et des sciences de la santé, Université de Sherbrooke, Sherbrooke, QC, Canada
- Centre de recherche du CHUS, Sherbrooke, QC, Canada
| | - Louis Gendron
- Département de pharmacologie-physiologie, Université de Sherbrooke, Sherbrooke, QC, Canada.
- Institut de pharmacologie de Sherbrooke, Université de Sherbrooke, Sherbrooke, QC, Canada.
- Faculté de médecine et des sciences de la santé, Université de Sherbrooke, Sherbrooke, QC, Canada.
- Centre de recherche du CHUS, Sherbrooke, QC, Canada.
- Département d'anesthésiologie, Université de Sherbrooke, Sherbrooke, QC, Canada.
- Quebec Pain Research Network, Sherbrooke, QC, Canada.
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13
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Heath E, Chieng B, Christie MJ, Balleine BW. Substance P and dopamine interact to modulate the distribution of delta‐opioid receptors on cholinergic interneurons in the striatum. Eur J Neurosci 2017; 47:1159-1173. [DOI: 10.1111/ejn.13750] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/30/2017] [Revised: 10/11/2017] [Accepted: 10/12/2017] [Indexed: 11/28/2022]
Affiliation(s)
- Emily Heath
- Brain & Mind Centre University of Sydney Sydney NSW Australia
| | - Billy Chieng
- Decision Neuroscience Lab School of Psychology University of New South Wales Kensington NSW 2052 Australia
| | | | - Bernard W. Balleine
- Brain & Mind Centre University of Sydney Sydney NSW Australia
- Decision Neuroscience Lab School of Psychology University of New South Wales Kensington NSW 2052 Australia
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14
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Jones AKP, Brown CA. Predictive mechanisms linking brain opioids to chronic pain vulnerability and resilience. Br J Pharmacol 2017; 175:2778-2790. [PMID: 28449262 DOI: 10.1111/bph.13840] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/16/2017] [Revised: 03/16/2017] [Accepted: 04/18/2017] [Indexed: 12/11/2022] Open
Abstract
Chronic pain is a major global healthcare problem that is currently inadequately treated. In addition, the current use of opioids for treatment has reached far beyond the paucity of evidence for long-term benefits relative to risks. Benefit-risk models for opioid and non-opioid treatments would benefit from a rational, mechanism-based understanding of neuroplastic and neurochemical contributions to chronic pain. Here, we evaluate the findings and limitations of representative research investigating brain neuroplasticity and neurochemistry in chronic pain. In sum, the mechanisms of pain-related neuroplasticity in the brain remain poorly understood because neuroimaging studies have been largely descriptive. We argue that definition is needed of optimal (pain-resilient) and suboptimal (pain-vulnerable) functioning of the endogenous opioid system in order to identify neurochemical contributions to aberrant neuroplasticity in chronic pain. We outline the potential benefits of computational approaches that utilize evolutionary and statistical optimality principles, illustrating this approach with mechanistic hypotheses on opioid function. In particular, we discuss the role of predictive mechanisms in perceptual and associative plasticity and evidence for their modulation by endogenous opioids. Future research should attempt to utilize formal computational models to provide evidence for the clinical validity of this approach, thereby providing a rational basis for future treatment and, ideally, prevention. LINKED ARTICLES This article is part of a themed section on Emerging Areas of Opioid Pharmacology. To view the other articles in this section visit http://onlinelibrary.wiley.com/doi/10.1111/bph.v175.14/issuetoc.
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Affiliation(s)
- Anthony Kenneth Peter Jones
- Human Pain Research Group, Division of Neuroscience & Experimental Psychology, School of Biology, University of Manchester, Manchester, UK
| | - Christopher Andrew Brown
- Human Pain Research Group, Division of Neuroscience & Experimental Psychology, School of Biology, University of Manchester, Manchester, UK.,Department of Psychological Sciences, Faculty of Psychology, Health and Society, University of Liverpool, Liverpool, UK
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15
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Gendron L, Cahill CM, von Zastrow M, Schiller PW, Pineyro G. Molecular Pharmacology of δ-Opioid Receptors. Pharmacol Rev 2017; 68:631-700. [PMID: 27343248 DOI: 10.1124/pr.114.008979] [Citation(s) in RCA: 89] [Impact Index Per Article: 12.7] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/08/2023] Open
Abstract
Opioids are among the most effective analgesics available and are the first choice in the treatment of acute severe pain. However, partial efficacy, a tendency to produce tolerance, and a host of ill-tolerated side effects make clinically available opioids less effective in the management of chronic pain syndromes. Given that most therapeutic opioids produce their actions via µ-opioid receptors (MOPrs), other targets are constantly being explored, among which δ-opioid receptors (DOPrs) are being increasingly considered as promising alternatives. This review addresses DOPrs from the perspective of cellular and molecular determinants of their pharmacological diversity. Thus, DOPr ligands are examined in terms of structural and functional variety, DOPrs' capacity to engage a multiplicity of canonical and noncanonical G protein-dependent responses is surveyed, and evidence supporting ligand-specific signaling and regulation is analyzed. Pharmacological DOPr subtypes are examined in light of the ability of DOPr to organize into multimeric arrays and to adopt multiple active conformations as well as differences in ligand kinetics. Current knowledge on DOPr targeting to the membrane is examined as a means of understanding how these receptors are especially active in chronic pain management. Insight into cellular and molecular mechanisms of pharmacological diversity should guide the rational design of more effective, longer-lasting, and better-tolerated opioid analgesics for chronic pain management.
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Affiliation(s)
- Louis Gendron
- Département de Pharmacologie-Physiologie, Faculté de médecine et des sciences de la santé, Université de Sherbrooke, Centre de Recherche du CHU de Sherbrooke, Centre d'excellence en neurosciences de l'Univeristé de Sherbrooke, and Institut de Pharmacologie de Sherbrooke, Sherbrooke, Quebec, Canada (L.G.); Québec Pain Research Network, Sherbrooke, Quebec, Canada (L.G.); Departments of Anesthesiology and Perioperative Care and Pharmacology, University of California, Irvine, California (C.M.C.); Department of Biomedical and Molecular Sciences, Queen's University, Kingston, Ontario, Canada (C.M.C.); Departments of Psychiatry and Cellular and Molecular Pharmacology, University of California, San Francisco, California (M.v.Z.); Laboratory of Chemical Biology and Peptide Research, Clinical Research Institute of Montréal, Montreal, Quebec, Canada (P.W.S.); and Departments of Psychiatry, Pharmacology, and Neurosciences, Faculty of Medicine, University of Montréal and Sainte-Justine Hospital Research Center, Montreal, Quebec, Canada (G.P.)
| | - Catherine M Cahill
- Département de Pharmacologie-Physiologie, Faculté de médecine et des sciences de la santé, Université de Sherbrooke, Centre de Recherche du CHU de Sherbrooke, Centre d'excellence en neurosciences de l'Univeristé de Sherbrooke, and Institut de Pharmacologie de Sherbrooke, Sherbrooke, Quebec, Canada (L.G.); Québec Pain Research Network, Sherbrooke, Quebec, Canada (L.G.); Departments of Anesthesiology and Perioperative Care and Pharmacology, University of California, Irvine, California (C.M.C.); Department of Biomedical and Molecular Sciences, Queen's University, Kingston, Ontario, Canada (C.M.C.); Departments of Psychiatry and Cellular and Molecular Pharmacology, University of California, San Francisco, California (M.v.Z.); Laboratory of Chemical Biology and Peptide Research, Clinical Research Institute of Montréal, Montreal, Quebec, Canada (P.W.S.); and Departments of Psychiatry, Pharmacology, and Neurosciences, Faculty of Medicine, University of Montréal and Sainte-Justine Hospital Research Center, Montreal, Quebec, Canada (G.P.)
| | - Mark von Zastrow
- Département de Pharmacologie-Physiologie, Faculté de médecine et des sciences de la santé, Université de Sherbrooke, Centre de Recherche du CHU de Sherbrooke, Centre d'excellence en neurosciences de l'Univeristé de Sherbrooke, and Institut de Pharmacologie de Sherbrooke, Sherbrooke, Quebec, Canada (L.G.); Québec Pain Research Network, Sherbrooke, Quebec, Canada (L.G.); Departments of Anesthesiology and Perioperative Care and Pharmacology, University of California, Irvine, California (C.M.C.); Department of Biomedical and Molecular Sciences, Queen's University, Kingston, Ontario, Canada (C.M.C.); Departments of Psychiatry and Cellular and Molecular Pharmacology, University of California, San Francisco, California (M.v.Z.); Laboratory of Chemical Biology and Peptide Research, Clinical Research Institute of Montréal, Montreal, Quebec, Canada (P.W.S.); and Departments of Psychiatry, Pharmacology, and Neurosciences, Faculty of Medicine, University of Montréal and Sainte-Justine Hospital Research Center, Montreal, Quebec, Canada (G.P.)
| | - Peter W Schiller
- Département de Pharmacologie-Physiologie, Faculté de médecine et des sciences de la santé, Université de Sherbrooke, Centre de Recherche du CHU de Sherbrooke, Centre d'excellence en neurosciences de l'Univeristé de Sherbrooke, and Institut de Pharmacologie de Sherbrooke, Sherbrooke, Quebec, Canada (L.G.); Québec Pain Research Network, Sherbrooke, Quebec, Canada (L.G.); Departments of Anesthesiology and Perioperative Care and Pharmacology, University of California, Irvine, California (C.M.C.); Department of Biomedical and Molecular Sciences, Queen's University, Kingston, Ontario, Canada (C.M.C.); Departments of Psychiatry and Cellular and Molecular Pharmacology, University of California, San Francisco, California (M.v.Z.); Laboratory of Chemical Biology and Peptide Research, Clinical Research Institute of Montréal, Montreal, Quebec, Canada (P.W.S.); and Departments of Psychiatry, Pharmacology, and Neurosciences, Faculty of Medicine, University of Montréal and Sainte-Justine Hospital Research Center, Montreal, Quebec, Canada (G.P.)
| | - Graciela Pineyro
- Département de Pharmacologie-Physiologie, Faculté de médecine et des sciences de la santé, Université de Sherbrooke, Centre de Recherche du CHU de Sherbrooke, Centre d'excellence en neurosciences de l'Univeristé de Sherbrooke, and Institut de Pharmacologie de Sherbrooke, Sherbrooke, Quebec, Canada (L.G.); Québec Pain Research Network, Sherbrooke, Quebec, Canada (L.G.); Departments of Anesthesiology and Perioperative Care and Pharmacology, University of California, Irvine, California (C.M.C.); Department of Biomedical and Molecular Sciences, Queen's University, Kingston, Ontario, Canada (C.M.C.); Departments of Psychiatry and Cellular and Molecular Pharmacology, University of California, San Francisco, California (M.v.Z.); Laboratory of Chemical Biology and Peptide Research, Clinical Research Institute of Montréal, Montreal, Quebec, Canada (P.W.S.); and Departments of Psychiatry, Pharmacology, and Neurosciences, Faculty of Medicine, University of Montréal and Sainte-Justine Hospital Research Center, Montreal, Quebec, Canada (G.P.)
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16
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St-Louis É, Degrandmaison J, Grastilleur S, Génier S, Blais V, Lavoie C, Parent JL, Gendron L. Involvement of the coatomer protein complex I in the intracellular traffic of the delta opioid receptor. Mol Cell Neurosci 2016; 79:53-63. [PMID: 28041939 DOI: 10.1016/j.mcn.2016.12.005] [Citation(s) in RCA: 19] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/16/2016] [Revised: 12/01/2016] [Accepted: 12/26/2016] [Indexed: 11/16/2022] Open
Abstract
The delta opioid receptor (DOPr) is known to be mainly expressed in intracellular compartments. It remains unknown why DOPr is barely exported to the cell surface, but it seems that a substantial proportion of the immature receptor is trapped within the endoplasmic reticulum (ER) and the Golgi network. In the present study, we performed LC-MS/MS analysis to identify putative protein partners involved in the retention of DOPr. Analysis of the proteins co-immunoprecipitating with Flag-DOPr in transfected HEK293 cells revealed the presence of numerous subunits of the coatomer protein complex I (COPI), a vesicle-coating complex involved in recycling resident proteins from the Golgi back to the ER. Further analysis of the amino acid sequence of DOPr identified multiple consensus di-lysine and di-arginine motifs within the intracellular segments of DOPr. Using cell-surface ELISA and GST pulldown assays, we showed that DOPr interacts with COPI through its intracellular loops 2 and 3 (ICL2 and ICL3, respectively) and that the mutation of the K164AK166 (ICL2) or K250EK252 (ICL3) putative COPI binding sites increased the cell-surface expression of DOPr in transfected cells. Altogether, our results indicate that COPI is a binding partner of DOPr and provide a putative mechanism to explain why DOPr is highly retained inside the cells.
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Affiliation(s)
- Étienne St-Louis
- Département de pharmacologie-physiologie, Université de Sherbrooke, Sherbrooke, Québec, Canada; Institut de pharmacologie de Sherbrooke, Université de Sherbrooke, Sherbrooke, Québec, Canada; Faculté de médecine et des sciences de la santé, Université de Sherbrooke, Sherbrooke, Québec, Canada; Centre de recherche du CHUS, Sherbrooke, Québec, Canada
| | - Jade Degrandmaison
- Département de médecine, Université de Sherbrooke, Sherbrooke, Québec, Canada; Institut de pharmacologie de Sherbrooke, Université de Sherbrooke, Sherbrooke, Québec, Canada; Faculté de médecine et des sciences de la santé, Université de Sherbrooke, Sherbrooke, Québec, Canada; Centre de recherche du CHUS, Sherbrooke, Québec, Canada
| | - Sébastien Grastilleur
- Département de pharmacologie-physiologie, Université de Sherbrooke, Sherbrooke, Québec, Canada; Institut de pharmacologie de Sherbrooke, Université de Sherbrooke, Sherbrooke, Québec, Canada; Faculté de médecine et des sciences de la santé, Université de Sherbrooke, Sherbrooke, Québec, Canada; Centre de recherche du CHUS, Sherbrooke, Québec, Canada
| | - Samuel Génier
- Département de médecine, Université de Sherbrooke, Sherbrooke, Québec, Canada; Institut de pharmacologie de Sherbrooke, Université de Sherbrooke, Sherbrooke, Québec, Canada; Faculté de médecine et des sciences de la santé, Université de Sherbrooke, Sherbrooke, Québec, Canada; Centre de recherche du CHUS, Sherbrooke, Québec, Canada
| | - Véronique Blais
- Département de pharmacologie-physiologie, Université de Sherbrooke, Sherbrooke, Québec, Canada; Institut de pharmacologie de Sherbrooke, Université de Sherbrooke, Sherbrooke, Québec, Canada; Faculté de médecine et des sciences de la santé, Université de Sherbrooke, Sherbrooke, Québec, Canada; Centre de recherche du CHUS, Sherbrooke, Québec, Canada
| | - Christine Lavoie
- Département de pharmacologie-physiologie, Université de Sherbrooke, Sherbrooke, Québec, Canada; Institut de pharmacologie de Sherbrooke, Université de Sherbrooke, Sherbrooke, Québec, Canada; Faculté de médecine et des sciences de la santé, Université de Sherbrooke, Sherbrooke, Québec, Canada; Centre de recherche du CHUS, Sherbrooke, Québec, Canada
| | - Jean-Luc Parent
- Département de médecine, Université de Sherbrooke, Sherbrooke, Québec, Canada; Institut de pharmacologie de Sherbrooke, Université de Sherbrooke, Sherbrooke, Québec, Canada; Faculté de médecine et des sciences de la santé, Université de Sherbrooke, Sherbrooke, Québec, Canada; Centre de recherche du CHUS, Sherbrooke, Québec, Canada.
| | - Louis Gendron
- Département de pharmacologie-physiologie, Université de Sherbrooke, Sherbrooke, Québec, Canada; Département d'anesthésiologie, Université de Sherbrooke, Sherbrooke, Québec, Canada; Institut de pharmacologie de Sherbrooke, Université de Sherbrooke, Sherbrooke, Québec, Canada; Faculté de médecine et des sciences de la santé, Université de Sherbrooke, Sherbrooke, Québec, Canada; Centre de recherche du CHUS, Sherbrooke, Québec, Canada; Quebec Pain Research Network, Québec, Canada.
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17
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Striatal opioid receptor availability is related to acute and chronic pain perception in arthritis: does opioid adaptation increase resilience to chronic pain? Pain 2016; 156:2267-2275. [PMID: 26176892 DOI: 10.1097/j.pain.0000000000000299] [Citation(s) in RCA: 27] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/06/2023]
Abstract
The experience of pain in humans is modulated by endogenous opioids, but it is largely unknown how the opioid system adapts to chronic pain states. Animal models of chronic pain point to upregulation of opioid receptors (OpR) in the brain, with unknown functional significance. We sought evidence for a similar relationship between chronic pain and OpR availability in humans. Using positron emission tomography and the radiotracer (11)C-diprenorphine, patients with arthritis pain (n = 17) and healthy controls (n = 9) underwent whole-brain positron emission tomography scanning to calculate parametric maps of OpR availability. Consistent with the upregulation hypothesis, within the arthritis group, greater OpR availability was found in the striatum (including the caudate) of patients reporting higher levels of recent chronic pain, as well as regions of interest in the descending opioidergic pathway including the anterior cingulate cortex, thalamus, and periaqueductal gray. The functional significance of striatal changes were clarified with respect to acute pain thresholds: data across patients and controls revealed that striatal OpR availability was related to reduced pain perception. These findings are consistent with the view that chronic pain may upregulate OpR availability to dampen pain. Finally, patients with arthritis pain, compared with healthy controls, had overall less OpR availability within the striatum specifically, consistent with the greater endogenous opioid binding that would be expected in chronic pain states. Our observational evidence points to the need for further studies to establish the causal relationship between chronic pain states and OpR adaptation.
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18
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Vicente-Sanchez A, Segura L, Pradhan AA. The delta opioid receptor tool box. Neuroscience 2016; 338:145-159. [PMID: 27349452 DOI: 10.1016/j.neuroscience.2016.06.028] [Citation(s) in RCA: 20] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/21/2016] [Revised: 05/29/2016] [Accepted: 06/16/2016] [Indexed: 12/14/2022]
Abstract
In recent years, the delta opioid receptor has attracted increasing interest as a target for the treatment of chronic pain and emotional disorders. Due to their therapeutic potential, numerous tools have been developed to study the delta opioid receptor from both a molecular and a functional perspective. This review summarizes the most commonly available tools, with an emphasis on their use and limitations. Here, we describe (1) the cell-based assays used to study the delta opioid receptor. (2) The features of several delta opioid receptor ligands, including peptide and non-peptide drugs. (3) The existing approaches to detect delta opioid receptors in fixed tissue, and debates that surround these techniques. (4) Behavioral assays used to study the in vivo effects of delta opioid receptor agonists; including locomotor stimulation and convulsions that are induced by some ligands, but not others. (5) The characterization of genetically modified mice used specifically to study the delta opioid receptor. Overall, this review aims to provide a guideline for the use of these tools with the final goal of increasing our understanding of delta opioid receptor physiology.
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Affiliation(s)
| | - Laura Segura
- Department of Psychiatry, University of Illinois at Chicago, United States
| | - Amynah A Pradhan
- Department of Psychiatry, University of Illinois at Chicago, United States.
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19
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Erbs E, Faget L, Ceredig RA, Matifas A, Vonesch JL, Kieffer BL, Massotte D. Impact of chronic morphine on delta opioid receptor-expressing neurons in the mouse hippocampus. Neuroscience 2015; 313:46-56. [PMID: 26480813 DOI: 10.1016/j.neuroscience.2015.10.022] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/27/2015] [Revised: 10/08/2015] [Accepted: 10/12/2015] [Indexed: 11/18/2022]
Abstract
Delta opioid (DOP) receptors participate to the control of chronic pain and emotional responses. Recent data also identified their implication in spatial memory and drug-context associations pointing to a critical role of hippocampal delta receptors. To better appreciate the impact of repeated drug exposure on their modulatory activity, we used fluorescent knock-in mice that express a functional delta receptor fused at its carboxy-terminus with the green fluorescent protein in place of the native receptor. We then tested the impact of chronic morphine treatment on the density and distribution of delta receptor-expressing cells in the hippocampus. A decrease in delta receptor-positive cell density was observed in the CA1, CA3 and dentate gyrus without alteration of the distribution across the different GABAergic populations that mainly express delta receptors. This effect partly persisted after four weeks of morphine abstinence. In addition, we observed increased DOP receptor expression at the cell surface compared to saline-treated animals. In the hippocampus, chronic morphine administration thus induces DOP receptor cellular redistribution and durably decreases delta receptor-expressing cell density. Such modifications are likely to alter hippocampal physiology, and to contribute to long-term cognitive deficits.
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Affiliation(s)
- E Erbs
- Institut de Génétique et de Biologie Moléculaire et Cellulaire (IGBMC), CNRS/INSERM/UdS, 1 Rue Laurent Fries, F-67404 Illkirch-Graffenstaden, France
| | - L Faget
- Institut de Génétique et de Biologie Moléculaire et Cellulaire (IGBMC), CNRS/INSERM/UdS, 1 Rue Laurent Fries, F-67404 Illkirch-Graffenstaden, France
| | - R A Ceredig
- Institut des Neurosciences Cellulaires et Intégratives, UPR 3212, 5 Rue Blaise Pascal, F-67084 Strasbourg, France
| | - A Matifas
- Institut de Génétique et de Biologie Moléculaire et Cellulaire (IGBMC), CNRS/INSERM/UdS, 1 Rue Laurent Fries, F-67404 Illkirch-Graffenstaden, France
| | - J-L Vonesch
- Imaging Center IGBMC, CNRS/INSERM/UdS, 1 Rue Laurent Fries, F-67404 Illkirch-Graffenstaden, France
| | - B L Kieffer
- Institut de Génétique et de Biologie Moléculaire et Cellulaire (IGBMC), CNRS/INSERM/UdS, 1 Rue Laurent Fries, F-67404 Illkirch-Graffenstaden, France; Douglas Hospital Research Center, Department of Psychiatry, McGill University, 6875, Boulevard LaSalle, Montreal (Quebec) H4H 1R3, Canada
| | - D Massotte
- Institut de Génétique et de Biologie Moléculaire et Cellulaire (IGBMC), CNRS/INSERM/UdS, 1 Rue Laurent Fries, F-67404 Illkirch-Graffenstaden, France; Institut des Neurosciences Cellulaires et Intégratives, UPR 3212, 5 Rue Blaise Pascal, F-67084 Strasbourg, France.
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20
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Chronic Morphine Reduces Surface Expression of δ-Opioid Receptors in Subregions of Rostral Striatum. Neurochem Res 2015; 41:500-9. [DOI: 10.1007/s11064-015-1638-6] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/13/2015] [Revised: 06/05/2015] [Accepted: 06/09/2015] [Indexed: 01/01/2023]
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21
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Pradhan AA, Tawfik VL, Tipton AF, Scherrer G. In vivo techniques to investigate the internalization profile of opioid receptors. Methods Mol Biol 2015; 1230:87-104. [PMID: 25293318 DOI: 10.1007/978-1-4939-1708-2_7] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/23/2022]
Abstract
G-protein-coupled receptors (GPCRs) regulate a remarkable diversity of biological functions, and are thus often targeted for drug therapies. Receptor internalization is commonly observed following agonist binding and activation. Receptor trafficking events have been well characterized in cell systems, but the in vivo significance of GPCR internalization is still poorly understood. To address this issue, we have developed an innovative knock-in mouse model, where an opioid receptor is directly visible in vivo. These knockin mice express functional fluorescent delta opioid receptors (DOR-eGFP) in place of the endogenous receptor, and these receptors are expressed at physiological levels within their native environment. DOR-eGFP mice have proven to be an extraordinary tool in studying receptor neuroanatomy, real-time receptor trafficking in live neurons, and in vivo receptor internalization. We have used this animal model to determine the relationship between receptor trafficking in neurons and receptor function at a behavioral level. Here, we describe in detail the construction and characterization of this knockin mouse. We also outline how to use these mice to examine the behavioral consequences of agonist-specific trafficking at the delta opioid receptor. These techniques are potentially applicable to any GPCR, and highlight the powerful nature of this imaging tool.
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Affiliation(s)
- Amynah A Pradhan
- Department of Psychiatry, University of Illinois at Chicago, 1601 W Taylor Street, Chicago, IL, 60612, USA,
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Beaudry H, Mercier-Blais AA, Delaygue C, Lavoie C, Parent JL, Neugebauer W, Gendron L. Regulation of μ and δ opioid receptor functions: involvement of cyclin-dependent kinase 5. Br J Pharmacol 2015; 172:2573-87. [PMID: 25598508 PMCID: PMC4409908 DOI: 10.1111/bph.13088] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/04/2014] [Revised: 12/18/2014] [Accepted: 01/05/2015] [Indexed: 12/26/2022] Open
Abstract
Background and Purpose Phosphorylation of δ opioid receptors (DOP receptors) by cyclin-dependent kinase 5 (CDK5) was shown to regulate the trafficking of this receptor. Therefore, we aimed to determine the role of CDK5 in regulating DOP receptors in rats treated with morphine or with complete Freund's adjuvant (CFA). As μ (MOP) and DOP receptors are known to be co-regulated, we also sought to determine if CDK5-mediated regulation of DOP receptors also affects MOP receptor functions. Experimental Approach The role of CDK5 in regulating opioid receptors in CFA- and morphine-treated rats was studied using roscovitine as a CDK inhibitor and a cell-penetrant peptide mimicking the second intracellular loop of DOP receptors (C11-DOPri2). Opioid receptor functions were assessed in vivo in a series of behavioural experiments and correlated by measuring ERK1/2 activity in dorsal root ganglia homogenates. Key Results Chronic roscovitine treatment reduced the antinociceptive and antihyperalgesic effects of deltorphin II (Dlt II) in morphine- and CFA-treated rats respectively. Repeated administrations of C11-DOPri2 also robustly decreased Dlt II-induced analgesia. Interestingly, DAMGO-induced analgesia was significantly increased by roscovitine and C11-DOPri2. Concomitantly, in roscovitine-treated rats the Dlt II-induced ERK1/2 activation was decreased, whereas the DAMGO-induced ERK1/2 activation was increased. An acute roscovitine treatment had no effect on Dlt II- or DAMGO-induced analgesia. Conclusions and Implications Together, our results demonstrate that CDK5 is a key player in the regulation of DOP receptors in morphine- and CFA-treated rats and that the regulation of DOP receptors by CDK5 is sufficient to modulate MOP receptor functions through an indirect process.
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Affiliation(s)
- H Beaudry
- Département de Physiologie et Biophysique, Université de Sherbrooke, Sherbrooke, QC, Canada; Centre de Recherche du Centre Hospitalier Universitaire de Sherbrooke, Université de Sherbrooke, Sherbrooke, QC, Canada; Faculté de Médecine et des Sciences de la Santé, Université de Sherbrooke, Sherbrooke, QC, Canada
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Beaudry H, Gendron L, Morón JA. Implication of delta opioid receptor subtype 2 but not delta opioid receptor subtype 1 in the development of morphine analgesic tolerance in a rat model of chronic inflammatory pain. Eur J Neurosci 2015; 41:901--7. [PMID: 25639561 DOI: 10.1111/ejn.12829] [Citation(s) in RCA: 18] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/08/2014] [Revised: 11/11/2014] [Accepted: 12/10/2014] [Indexed: 12/20/2022]
Abstract
Opioids are well known for their robust analgesic effects. Chronic activation of mu opioid receptors (MOPs) is, however, accompanied by various unwanted effects such as analgesic tolerance. Among other mechanisms, interactions between MOPs and delta opioid receptors (DOPs) are thought to play an important role in morphine-induced behavioral adaptations. Interestingly, certain conditions such as inflammation enhance the function of the DOP through a MOP-dependent mechanism. Here, we investigated the role of DOPs during the development of morphine tolerance in an animal model of chronic inflammatory pain. Using behavioral approaches, we first established that repeated systemic morphine treatment induced morphine analgesic tolerance in rats coping with chronic inflammatory pain. We then observed that blockade of DOPs with subcutaneous naltrindole (NTI), a selective DOP antagonist, significantly attenuated the development of morphine tolerance in a dose-dependent manner. We confirmed that this effect was DOP mediated by showing that an acute injection of NTI had no effect on morphine-induced analgesia in naive animals. Previous pharmacological characterizations revealed the existence of DOP subtype 1 and DOP subtype 2. As opposed to NTI, 7-benzylidenenaltrexone and naltriben were reported to be selective DOP subtype 1 and DOP subtype 2 antagonists, respectively. Interestingly, naltriben but not 7-benzylidenenaltrexone was able to attenuate the development of morphine analgesic tolerance in inflamed rats. Altogether, our results suggest that targeting of DOP subtype 2 with antagonists provides a valuable strategy to attenuate the analgesic tolerance that develops after repeated morphine administration in the setting of chronic inflammatory pain.
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Affiliation(s)
- H Beaudry
- Department of Anesthesiology, College of Physicians and Surgeons, Columbia University Medical Center, Columbia University, P&S Box 46, 630 West 168th Street, New York, NY, 10032, USA; Department of Physiology and Biophysics, Faculty of Medicine and Health Sciences, Université de Sherbrooke, 3001, 12th Avenue North, Sherbrooke, QC, J1H 5N4, Canada
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Gomes I, Gupta A, Bushlin I, Devi LA. Antibodies to probe endogenous G protein-coupled receptor heteromer expression, regulation, and function. Front Pharmacol 2014; 5:268. [PMID: 25520661 PMCID: PMC4253664 DOI: 10.3389/fphar.2014.00268] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/17/2014] [Accepted: 11/16/2014] [Indexed: 11/13/2022] Open
Abstract
Over the last decade an increasing number of studies have focused on the ability of G protein-coupled receptors to form heteromers and explored how receptor heteromerization modulates the binding, signaling and trafficking properties of individual receptors. Most of these studies were carried out in heterologous cells expressing epitope tagged receptors. Very little information is available about the in vivo physiological role of G protein-coupled receptor heteromers due to a lack of tools to detect their presence in endogenous tissue. Recent advances such as the generation of mouse models expressing fluorescently labeled receptors, of TAT based peptides that can disrupt a given heteromer pair, or of heteromer-selective antibodies that recognize the heteromer in endogenous tissue have begun to elucidate the physiological and pathological roles of receptor heteromers. In this review we have focused on heteromer-selective antibodies and describe how a subtractive immunization strategy can be successfully used to generate antibodies that selectively recognize a desired heteromer pair. We also describe the uses of these antibodies to detect the presence of heteromers, to study their properties in endogenous tissues, and to monitor changes in heteromer levels under pathological conditions. Together, these findings suggest that G protein-coupled receptor heteromers represent unique targets for the development of drugs with reduced side-effects.
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Affiliation(s)
- Ivone Gomes
- Department of Pharmacology and Systems Therapeutics, Icahn School of Medicine at Mount Sinai New York, NY, USA
| | - Achla Gupta
- Department of Pharmacology and Systems Therapeutics, Icahn School of Medicine at Mount Sinai New York, NY, USA
| | - Ittai Bushlin
- Department of Pharmacology and Systems Therapeutics, Icahn School of Medicine at Mount Sinai New York, NY, USA
| | - Lakshmi A Devi
- Department of Pharmacology and Systems Therapeutics, Icahn School of Medicine at Mount Sinai New York, NY, USA ; The Friedman Brain Institute, Icahn School of Medicine at Mount Sinai New York, NY, USA
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Schuster DJ, Metcalf MD, Kitto KF, Messing RO, Fairbanks CA, Wilcox GL. Ligand requirements for involvement of PKCε in synergistic analgesic interactions between spinal μ and δ opioid receptors. Br J Pharmacol 2014; 172:642-53. [PMID: 24827408 DOI: 10.1111/bph.12774] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/02/2013] [Revised: 04/29/2014] [Accepted: 05/01/2014] [Indexed: 12/17/2022] Open
Abstract
BACKGROUND AND PURPOSE We recently found that PKCε was required for spinal analgesic synergy between two GPCRs, δ opioid receptors and α2 A adrenoceptors, co-located in the same cellular subpopulation. We sought to determine if co-delivery of μ and δ opioid receptor agonists would similarly result in synergy requiring PKCε. EXPERIMENTAL APPROACH Combinations of μ and δ opioid receptor agonists were co-administered intrathecally by direct lumbar puncture to PKCε-wild-type (PKCε-WT) and -knockout (PKCε-KO) mice. Antinociception was assessed using the hot-water tail-flick assay. Drug interactions were evaluated by isobolographic analysis. KEY RESULTS All agonists produced comparable antinociception in both PKCε-WT and PKCε-KO mice. Of 19 agonist combinations that produced analgesic synergy, only 3 required PKCε for a synergistic interaction. In these three combinations, one of the agonists was morphine, although not all combinations involving morphine required PKCε. Morphine + deltorphin II and morphine + deltorphin I required PKCε for synergy, whereas a similar combination, morphine + deltorphin, did not. Additionally, morphine + oxymorphindole required PKCε for synergy, whereas a similar combination, morphine + oxycodindole, did not. CONCLUSIONS AND IMPLICATIONS We discovered biased agonism for a specific signalling pathway at the level of spinally co-delivered opioid agonists. As the bias is only revealed by an appropriate ligand combination and cannot be accounted for by a single drug, it is likely that the receptors these agonists act on are interacting with each other. Our results support the existence of μ and δ opioid receptor heteromers at the spinal level in vivo. LINKED ARTICLES This article is part of a themed section on Opioids: New Pathways to Functional Selectivity. To view the other articles in this section visit http://dx.doi.org/10.1111/bph.2015.172.issue-2.
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Affiliation(s)
- D J Schuster
- Department of Neuroscience, Medical School, University of Minnesota, Minneapolis, MN, USA
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Klenowski P, Morgan M, Bartlett SE. The role of δ-opioid receptors in learning and memory underlying the development of addiction. Br J Pharmacol 2014; 172:297-310. [PMID: 24641428 DOI: 10.1111/bph.12618] [Citation(s) in RCA: 31] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/01/2013] [Revised: 01/10/2014] [Accepted: 01/19/2014] [Indexed: 01/14/2023] Open
Abstract
UNLABELLED Opioids are important endogenous ligands that exist in both invertebrates and vertebrates and signal by activation of opioid receptors to produce analgesia and reward or pleasure. The μ-opioid receptor is the best known of the opioid receptors and mediates the acute analgesic effects of opiates, while the δ-opioid receptor (DOR) has been less well studied and has been linked to effects that follow from chronic use of opiates such as stress, inflammation and anxiety. Recently, DORs have been shown to play an essential role in emotions and increasing evidence points to a role in learning actions and outcomes. The process of learning and memory in addiction has been proposed to involve strengthening of specific brain circuits when a drug is paired with a context or environment. The DOR is highly expressed in the hippocampus, amygdala, striatum and other basal ganglia structures known to participate in learning and memory. In this review, we will focus on the role of the DOR and its potential role in learning and memory underlying the development of addiction. LINKED ARTICLES This article is part of a themed section on Opioids: New Pathways to Functional Selectivity. To view the other articles in this section visit http://dx.doi.org/10.1111/bph.2015.172.issue-2.
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Affiliation(s)
- Paul Klenowski
- Translational Research Institute, Institute for Health and Biomedical Innovation, Queensland University of Technology, Brisbane, QLD, Australia
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27
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Ong EW, Xue L, Olmstead MC, Cahill CM. Prolonged morphine treatment alters δ opioid receptor post-internalization trafficking. Br J Pharmacol 2014; 172:615-29. [PMID: 24819092 PMCID: PMC4292973 DOI: 10.1111/bph.12761] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/16/2013] [Revised: 04/15/2014] [Accepted: 04/29/2014] [Indexed: 01/15/2023] Open
Abstract
BACKGROUND AND PURPOSE The δ opioid receptor (DOP receptor) undergoes internalization both constitutively and in response to agonists. Previous work has shown that DOP receptors traffic from intracellular compartments to neuronal cell membranes following prolonged morphine treatment. Here, we examined the effects of prolonged morphine treatment on the post-internalization trafficking of DOP receptors. EXPERIMENTAL APPROACH Using primary cultures of dorsal root ganglia neurons, we measured the co-localization of endogenous DOP receptors with post-endocytic compartments following both prolonged and acute agonist treatments. KEY RESULTS A departure from the constitutive trafficking pathway was observed following acute DOP receptor agonist-induced internalization by deltorphin II. That is, the DOP receptor underwent distinct agonist-induced post-endocytic sorting. Following prolonged morphine treatment, constitutive DOP receptor trafficking was augmented. SNC80 following prolonged morphine treatment also caused non-constitutive DOP receptor agonist-induced post-endocytic sorting. The μ opioid receptor (MOP receptor) agonist DAMGO induced DOP receptor internalization and trafficking following prolonged morphine treatment. Finally, all of the alterations to DOP receptor trafficking induced by both DOP and MOP receptor agonists were inhibited or absent when those agonists were co-administered with a DOP receptor antagonist, SDM-25N. CONCLUSIONS AND IMPLICATIONS The results support the hypothesis that prolonged morphine treatment induces the formation of MOP–DOP receptor interactions and subsequent augmentation of the available cell surface DOP receptors, at least some of which are in the form of a MOP/DOP receptor species. The pharmacology and trafficking of this species appear to be unique compared to those of its individual constituents. LINKED ARTICLES This article is part of a themed section on Opioids: New Pathways to Functional Selectivity. To view the other articles in this section visit http://dx.doi.org/10.1111/bph.2015.172.issue-2
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Affiliation(s)
- E W Ong
- Department of Biomedical and Molecular Sciences, Queen's University, Kingston, ON, Canada; Department of Anaesthesiology and Perioperative Care, University of California, Irvine, CA, USA
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Chabot-Doré AJ, Schuster DJ, Stone LS, Wilcox GL. Analgesic synergy between opioid and α2 -adrenoceptors. Br J Pharmacol 2014; 172:388-402. [PMID: 24641506 DOI: 10.1111/bph.12695] [Citation(s) in RCA: 47] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/16/2013] [Revised: 03/08/2014] [Accepted: 03/12/2014] [Indexed: 12/24/2022] Open
Abstract
UNLABELLED Opioid and α2 -adrenoceptor agonists are potent analgesic drugs and their analgesic effects can synergize when co-administered. These supra-additive interactions are potentially beneficial clinically; by increasing efficacy and/or reducing the total drug required to produce sufficient pain relief, undesired side effects can be minimized. However, combination therapies of opioids and α2 -adrenoceptor agonists remain underutilized clinically, in spite of a large body of preclinical evidence describing their synergistic interaction. One possible obstacle to the translation of preclinical findings to clinical applications is a lack of understanding of the mechanisms underlying the synergistic interactions between these two drug classes. In this review, we provide a detailed overview of the interactions between different opioid and α2 -adrenoceptor agonist combinations in preclinical studies. These studies have identified the spinal cord as an important site of action of synergistic interactions, provided insights into which receptors mediate these interactions and explored downstream signalling events enabling synergy. It is now well documented that the activation of both μ and δ opioid receptors can produce synergy with α2 -adrenoceptor agonists and that α2 -adrenoceptor agonists can mediate synergy through either the α2A or the α2C adrenoceptor subtypes. Current hypotheses surrounding the cellular mechanisms mediating opioid-adrenoceptor synergy, including PKC signalling and receptor oligomerization, and the evidence supporting them are presented. Finally, the implications of these findings for clinical applications and drug discovery are discussed. LINKED ARTICLES This article is part of a themed section on Opioids: New Pathways to Functional Selectivity. To view the other articles in this section visit http://dx.doi.org/10.1111/bph.2015.172.issue-2.
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Affiliation(s)
- A-J Chabot-Doré
- Alan Edwards Centre for Research on Pain, McGill University, Montreal, QC, Canada; Department of Neurology and Neurosurgery, McGill University, Montreal, QC, Canada
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29
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Massotte D. In vivo opioid receptor heteromerization: where do we stand? Br J Pharmacol 2014; 172:420-34. [PMID: 24666391 DOI: 10.1111/bph.12702] [Citation(s) in RCA: 35] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/30/2013] [Revised: 03/17/2014] [Accepted: 03/19/2014] [Indexed: 12/22/2022] Open
Abstract
UNLABELLED Opioid receptors are highly homologous GPCRs that modulate brain function at all levels of neural integration, including autonomous, sensory, emotional and cognitive processing. Opioid receptors functionally interact in vivo, but the underlying mechanisms involving direct receptor-receptor interactions, affecting signalling pathways or engaging different neuronal circuits, remain unsolved. Heteromer formation through direct physical interaction between two opioid receptors or between an opioid receptor and a non-opioid one has been postulated and can be characterized by specific ligand binding, receptor signalling and trafficking properties. However, despite numerous studies in heterologous systems, evidence for physical proximity in vivo is only available for a limited number of opioid heteromers, and their physiopathological implication remains largely unknown mostly due to the lack of appropriate tools. Nonetheless, data collected so far using endogenous receptors point to a crucial role for opioid heteromers as a molecular entity that could underlie human pathologies such as alcoholism, acute or chronic pain as well as psychiatric disorders. Opioid heteromers therefore stand as new therapeutic targets for the drug discovery field. LINKED ARTICLES This article is part of a themed section on Opioids: New Pathways to Functional Selectivity. To view the other articles in this section visit http://dx.doi.org/10.1111/bph.2015.172.issue-2.
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Affiliation(s)
- D Massotte
- Institut des Neurosciences Cellulaires et Intégratives, INCI, Strasbourg, France
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Gendron L, Mittal N, Beaudry H, Walwyn W. Recent advances on the δ opioid receptor: from trafficking to function. Br J Pharmacol 2014; 172:403-19. [PMID: 24665909 DOI: 10.1111/bph.12706] [Citation(s) in RCA: 62] [Impact Index Per Article: 6.2] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/15/2013] [Revised: 03/17/2014] [Accepted: 03/18/2014] [Indexed: 01/12/2023] Open
Abstract
UNLABELLED Within the opioid family of receptors, δ (DOPrs) and μ opioid receptors (MOPrs) are typical GPCRs that activate canonical second-messenger signalling cascades to influence diverse cellular functions in neuronal and non-neuronal cell types. These receptors activate well-known pathways to influence ion channel function and pathways such as the map kinase cascade, AC and PI3K. In addition new information regarding opioid receptor-interacting proteins, downstream signalling pathways and resultant functional effects has recently come to light. In this review, we will examine these novel findings focusing on the DOPr and, in doing so, will contrast and compare DOPrs with MOPrs in terms of differences and similarities in function, signalling pathways, distribution and interactions. We will also discuss and clarify issues that have recently surfaced regarding the expression and function of DOPrs in different cell types and analgesia. LINKED ARTICLES This article is part of a themed section on Opioids: New Pathways to Functional Selectivity. To view the other articles in this section visit http://dx.doi.org/10.1111/bph.2015.172.issue-2.
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Affiliation(s)
- Louis Gendron
- Département de physiologie et biophysique, Institut de pharmacologie de Sherbrooke, Faculté de médecine et des sciences de la santé, Université de Sherbrooke, Sherbrooke, QC, Canada
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31
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Kabli N, Fan T, O'Dowd BF, George SR. μ-δ opioid receptor heteromer-specific signaling in the striatum and hippocampus. Biochem Biophys Res Commun 2014; 450:906-11. [PMID: 24976397 DOI: 10.1016/j.bbrc.2014.06.099] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/02/2014] [Accepted: 06/19/2014] [Indexed: 01/28/2023]
Abstract
The μ-δ opioid receptor heteromer activates the pertussis toxin-resistant Gαz GTP-binding protein following stimulation by the δ-agonist deltorphin-II whereas μ- and δ-receptors activate the pertussis toxin-sensitive Gαi3 protein following stimulation by μ- and δ-agonists, respectively. Although the regulation of the μ-δ heteromer is being investigated extensively in vitro, its physiological relevance remains elusive owing to a lack of available molecular tools. We investigated μ-δ heteromer signaling under basal conditions and following prolonged morphine treatment in rodent brain regions highly co-expressing μ- and δ-receptors and Gαz. Deltorphin-II induced Gαz activation in the striatum and hippocampus, demonstrating the presence of μ-δ heteromer signaling in these brain regions. Prolonged morphine treatment, which desensitizes μ- and δ-receptor function, had no effect on μ-δ heteromer signaling in the brain. Our data demonstrate that μ-δ heteromer signaling does not desensitize and is regulated differently from μ- and δ-receptor signaling following prolonged morphine treatment.
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Affiliation(s)
- Noufissa Kabli
- Campbell Family Mental Health Research Institute, Centre for Addiction and Mental Health, 250 College Street, Toronto, Ontario M5T1R8, Canada; Department of Pharmacology, University of Toronto, Medical Sciences Building RM 4358, 1 King's College Circle, Toronto, Ontario M5S1A8, Canada
| | - Theresa Fan
- Campbell Family Mental Health Research Institute, Centre for Addiction and Mental Health, 250 College Street, Toronto, Ontario M5T1R8, Canada
| | - Brian F O'Dowd
- Campbell Family Mental Health Research Institute, Centre for Addiction and Mental Health, 250 College Street, Toronto, Ontario M5T1R8, Canada; Department of Pharmacology, University of Toronto, Medical Sciences Building RM 4358, 1 King's College Circle, Toronto, Ontario M5S1A8, Canada
| | - Susan R George
- Campbell Family Mental Health Research Institute, Centre for Addiction and Mental Health, 250 College Street, Toronto, Ontario M5T1R8, Canada; Department of Medicine, University of Toronto, Medical Sciences Building RM 4358, 1 King's College Circle, Toronto, Ontario M5S1A8, Canada; Department of Pharmacology, University of Toronto, Medical Sciences Building RM 4358, 1 King's College Circle, Toronto, Ontario M5S1A8, Canada.
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Ong EW, Cahill CM. Molecular Perspectives for mu/delta Opioid Receptor Heteromers as Distinct, Functional Receptors. Cells 2014; 3:152-79. [PMID: 24709907 PMCID: PMC3980742 DOI: 10.3390/cells3010152] [Citation(s) in RCA: 21] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/20/2013] [Revised: 02/14/2014] [Accepted: 02/21/2014] [Indexed: 02/06/2023] Open
Abstract
Opioid receptors are the sites of action for morphine and the other opioid drugs. Abundant evidence now demonstrates that different opioid receptor types can physically associate to form heteromers. Understandings of the nature, behavior, and role of these opioid receptor heteromers are developing. Owing to their constituent monomers’ involvement in analgesia, mu/delta opioid receptor (M/DOR) heteromers have been a particular focus of attention. There is now considerable evidence demonstrating M/DOR to be an extant and physiologically relevant receptor species. Participating in the cellular environment as a distinct receptor type, M/DOR availability is complexly regulated and M/DOR exhibits unique pharmacology from that of other opioid receptors (ORs), including its constituents. M/DOR appears to have a range of actions that vary in a ligand- (or ligands-) dependent manner. These actions can meaningfully affect the clinical effects of opioid drugs: strategies targeting M/DOR may be therapeutically useful. This review presents and discusses developments in these understandings with a focus on the molecular nature and activity of M/DOR in the context of therapeutic potentials.
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Affiliation(s)
- Edmund W Ong
- Department of Biomedical and Molecular Sciences, Queen's University, Kingston, Ontario K7L 3N6, Canada.
| | - Catherine M Cahill
- Department of Biomedical and Molecular Sciences, Queen's University, Kingston, Ontario K7L 3N6, Canada.
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Chabot-Doré AJ, Millecamps M, Stone LS. The Delta-Opioid Receptor Is Sufficient, but Not Necessary, for Spinal Opioid-Adrenergic Analgesic Synergy. J Pharmacol Exp Ther 2013; 347:773-80. [DOI: 10.1124/jpet.113.206581] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/05/2023] Open
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An intronic variant in OPRD1 predicts treatment outcome for opioid dependence in African-Americans. Neuropsychopharmacology 2013; 38:2003-10. [PMID: 23612435 PMCID: PMC3746708 DOI: 10.1038/npp.2013.99] [Citation(s) in RCA: 62] [Impact Index Per Article: 5.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 12/03/2012] [Revised: 04/05/2013] [Accepted: 04/06/2013] [Indexed: 12/21/2022]
Abstract
Although buprenorphine and methadone are both effective treatments for opioid dependence, their efficacy can vary significantly among patients. Genetic differences may explain some of the variability in treatment outcome. Understanding the interactions between genetic background and pharmacotherapy may result in more informed treatment decisions. This study is a pharmacogenetic analysis of the effects of genetic variants in OPRD1, the gene encoding the δ-opioid receptor, on the prevalence of opioid-positive urine tests in African-Americans (n=77) or European-Americans (n=566) undergoing treatment for opioid dependence. Patients were randomly assigned to treatment with either methadone or buprenorphine/naloxone (Suboxone) over a 24-week open-label clinical trial, in which illicit opioid use was measured by weekly urinalysis. In African-Americans, the intronic SNP rs678849 predicted treatment outcome for both medications. Methadone patients with the CC genotype were less likely to have opioid-positive urine tests than those in the combined CT and TT genotypes group (relative risk (RR)=0.52, 95% confidence interval (CI)=0.44-0.60, p=0.001). In the buprenorphine treatment group, however, individuals with the CC genotype were more likely to have positive opioid drug screens than individuals in the combined CT and TT genotypes group (RR=2.17, 95% CI=1.95-2.68, p=0.008). These findings indicate that the genotype at rs678849 predicts African-American patient response to two common treatments for opioid dependence, suggesting that matching patients to treatment type based on the genotype at this locus may improve overall treatment efficacy. This observation requires confirmation in an independent population.
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Leal AK, Yamauchi K, Kim J, Ruiz-Velasco V, Kaufman MP. Peripheral δ-opioid receptors attenuate the exercise pressor reflex. Am J Physiol Heart Circ Physiol 2013; 305:H1246-55. [PMID: 23934854 DOI: 10.1152/ajpheart.00116.2013] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
In rats with ligated femoral arteries, the exercise pressor reflex is exaggerated, an effect that is attenuated by stimulation of peripheral μ-opioid receptors on group IV metabosensitive afferents. In contrast, δ-opioid receptors are expressed mostly on group III mechanosensitive afferents, a finding that prompted us to determine whether stimulation of these opioid receptors could also attenuate the exaggerated exercise pressor reflex in "ligated" rats. We found femoral arterial injection of [D-Pen2,D-Pen5]enkephalin (DPDPE; 1.0 μg), a δ-opioid agonist, significantly attenuated the pressor and cardioaccelerator components of the exercise pressor reflex evoked by hindlimb muscle contraction in both rats with ligated and patent femoral arteries. DPDPE significantly decreased the pressor responses to muscle mechanoreflex activation, evoked by tendon stretch, in ligated rats only. DPDPE (1.0 μg) had no effect in either group on the pressor and cardioaccelerator responses to capsaicin (0.2 μg), which primarily stimulates group IV afferents. DPDPE (1.0 μg) had no effect on the pressor and cardioaccelerator responses to lactic acid (24 mM), which stimulates group III and IV afferents, in rats with patent femoral arteries but significantly decreased the pressor response in ligated rats. Western blots revealed the amount of protein comprising the δ-opioid receptor was greater in dorsal root ganglia innervating hindlimbs with ligated femoral arteries than in dorsal root ganglia innervating hindlimbs with patent femoral arteries. Our findings support the hypothesis that stimulation of δ-opioid receptors on group III afferents attenuated the exercise pressor reflex.
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Affiliation(s)
- Anna K Leal
- Heart and Vascular Institute, Penn State College of Medicine, Hershey, Pennsylvania; and
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36
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Pharmacological traits of delta opioid receptors: pitfalls or opportunities? Psychopharmacology (Berl) 2013; 228:1-18. [PMID: 23649885 PMCID: PMC3679311 DOI: 10.1007/s00213-013-3129-2] [Citation(s) in RCA: 34] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 02/15/2013] [Accepted: 04/15/2013] [Indexed: 12/11/2022]
Abstract
RATIONALE Delta opioid receptors (DORs) have been considered as a potential target to relieve pain as well as treat depression and anxiety disorders and are known to modulate other physiological responses, including ethanol and food consumption. A small number of DOR-selective drugs are in clinical trials, but no DOR-selective drugs have been approved by the Federal Drug Administration and some candidates have failed in phase II clinical trials, highlighting current difficulties producing effective delta opioid-based therapies. Recent studies have provided new insights into the pharmacology of the DOR, which is often complex and at times paradoxical. OBJECTIVE This review will discuss the existing literature focusing on four aspects: (1) Two DOR subtypes have been postulated based on differences in pharmacological effects of existing DOR-selective ligands. (2) DORs are expressed ubiquitously throughout the body and central nervous system and are, thus, positioned to play a role in a multitude of diseases. (3) DOR expression is often dynamic, with many reports of increased expression during exposure to chronic stimuli, such as stress, inflammation, neuropathy, morphine, or changes in endogenous opioid tone. (4) A large structural variety in DOR ligands implies potential different mechanisms of activating the receptor. CONCLUSION The reviewed features of DOR pharmacology illustrate the potential benefit of designing tailored or biased DOR ligands.
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Molet J, Pohl M. Gene-based approaches in pain research and exploration of new therapeutic targets and strategies. Eur J Pharmacol 2013; 716:129-41. [PMID: 23500201 DOI: 10.1016/j.ejphar.2013.01.073] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/30/2012] [Revised: 01/17/2013] [Accepted: 01/29/2013] [Indexed: 12/18/2022]
Abstract
Large panel of gene-based techniques is used for many years specifically in the pain research field. From the first identification (cloning) of some "mythic" genes, such as those encoding opioid or capsaicin receptors allowing then the creation of first-generation knockout mice, to the today conditional (time, tissue, cell-type and even pathology-dependent) and regulatable modulation of a gene function, these approaches largely contributed to fundamental leaps forward in our understanding of the function of some proteins and of their interest as possible druggable targets. Perhaps one of the most remarkable evolution in the last years is the passage of these approaches from the bench to the patient; whether it concerns the identification of genes involved in inherited pain insensibility/susceptibility, the search for genetic markers of pain types, the individual pharmacogenomics or even the first gene therapy trials. From many possible variants of gene-grounded techniques used in pain research we focus here on gene knockouts and some recent developments, on viral vectors-based gene transfer and on transgenic models for the tracing of pain pathways. Through these selected examples we attempted to emphasize the immense potential of these approaches and their already well-recognized contribution in both the basic and clinical pain research.
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Affiliation(s)
- Jenny Molet
- INSERM UMRS 975, CNRS UMR 7225, UPMC, Equipe Douleurs , Faculté de Médecine Pitié-Salpêtrière, 91 Bd de l'Hôpital, 75013 Paris, France.
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Kotlinska JH, Gibula-Bruzda E, Witkowska E, Chung NN, Schiller PW, Izdebski J. Antinociceptive effects of two deltorphins analogs in the tail-immersion test in rats. Peptides 2013. [PMID: 23183627 PMCID: PMC3934762 DOI: 10.1016/j.peptides.2012.11.008] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/13/2022]
Abstract
The antinociceptive effects of analogs of deltorphins: cyclo(Nδ,Nδ-carbonyl-D-Orn2, Orn4)deltorphin (DEL-6) and deltorphin II N-(ureidoethyl)amide (DK-4) after intracerebroventricular (i.c.v.) administration were investigated in the tail-immersion test in rats. Morphine, the most commonly used μ-opioid receptors (MOR) agonist, was employed as a reference compound. The contribution of the MOR, δ-(DOR) and κ-opioid receptors (KOR) in antinociceptive effects of the deltorphins analogs was studies using selective antagonists of these receptors. The results indicated that DK-4 (5, 10 and 20 nmol) and DEL-6 (5, 10 and 20 nmol) were the most effective in alleviating thermal pain at the dose of 20 nmol. The antinociceptive potency of DEL-6 at the dose of 20 nmol was approximately equal but DK-4 at the dose of 20 nmol was less effective than morphine at the dose of 13 nmol. DOR antagonist - naltrindole (NTI, 5 nmol) very strongly and, to the lower extent MOR antagonist - β-funaltrexamine (β-FNA, 5 nmol), inhibited antinociceptive effect of DK-4 (20 nmol). In turn, β-FNA was more potent than NTI in inhibition of the antinociceptive effects of DEL-6. Co-administration of DEL-6 and morphine at doses of 5 nmol, which do not produce measurable antinociception, generated additive antinociceptive effect. Chronic intraperitoneal (i.p.) injection of morphine (9 days) displayed a marked analgesic tolerance to the challenge dose of morphine and a slight cross-tolerance to challenge doses of DEL-6 and DK-4, given i.c.v. These findings indicate that the new deltorphin analogs recruit DOR and MOR to attenuate the nociceptive response to acute thermal stimuli.
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MESH Headings
- Analgesics, Opioid/administration & dosage
- Analgesics, Opioid/pharmacology
- Animals
- Drug Synergism
- Drug Tolerance
- Male
- Morphine/administration & dosage
- Morphine/pharmacology
- Naltrexone/analogs & derivatives
- Naltrexone/pharmacology
- Narcotic Antagonists/pharmacology
- Nociception/drug effects
- Oligopeptides/administration & dosage
- Oligopeptides/pharmacology
- Pain Measurement
- Rats
- Rats, Wistar
- Receptors, Opioid, delta/agonists
- Receptors, Opioid, delta/antagonists & inhibitors
- Receptors, Opioid, delta/metabolism
- Receptors, Opioid, kappa/agonists
- Receptors, Opioid, kappa/antagonists & inhibitors
- Receptors, Opioid, kappa/metabolism
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Affiliation(s)
- J H Kotlinska
- Department of Pharmacology and Pharmacodynamics, Medical University, Lublin, Poland.
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Abstract
Opiates such as morphine and fentanyl, a major class of analgesics used in the clinical management of pain, exert their effects through the activation of opioid receptors. Opioids are among the most commonly prescribed and frequently abused drugs in the USA; however, the prolonged use of opiates often leads to the development of tolerance and addiction. Although blockade of opioid receptors with antagonists such as naltrexone and naloxone can lessen addictive impulses and facilitate recovery from overdose, systemic disruption of endogenous opioid receptor signalling through the use of these antagonistic drugs can have severe side effects. In the light of these challenges, current efforts have focused on identifying new therapeutic targets that selectively and specifically modulate opioid receptor signalling and function so as to achieve analgesia without the adverse effects associated with chronic opiate use. We have previously reported that opioid receptors interact with each other to form heteromeric complexes and that these interactions affect morphine signalling. Since chronic morphine administration leads to an enhanced level of these heteromers, these opioid receptor heteromeric complexes represent novel therapeutic targets for the treatment of pain and opiate addiction. In this review, we discuss the role of heteromeric opioid receptor complexes with a focus on mu opioid receptor (MOR) and delta opioid receptor (DOR) heteromers. We also highlight the evidence for altered pharmacological properties of opioid ligands and changes in ligand function resulting from the heteromer formation.
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Stockton SD, Devi LA. Functional relevance of μ-δ opioid receptor heteromerization: a role in novel signaling and implications for the treatment of addiction disorders: from a symposium on new concepts in mu-opioid pharmacology. Drug Alcohol Depend 2012; 121:167-72. [PMID: 22115888 PMCID: PMC3288266 DOI: 10.1016/j.drugalcdep.2011.10.025] [Citation(s) in RCA: 32] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 05/03/2011] [Revised: 07/20/2011] [Accepted: 10/22/2011] [Indexed: 11/28/2022]
Abstract
Morphine and other opiates are among the most widely prescribed and clinically useful medications for the treatment of chronic pain. However, the applicability of these compounds has been severely hampered by the rapid development of tolerance and physical dependence that typically accompanies their repeated use. A growing body of evidence has implicated the regulated functioning of μ-δ opioid receptor heteromers in both the modulation of morphine-mediated antinociception, and in the limitation of undesirable side effects resulting from chronic opiate exposure. Moreover, μ-δ heteromers exhibit unique ligand binding characteristics and signaling properties, indicating that pharmacological targeting of the μ-δ heteromer may represent a novel therapeutic approach for the management of chronic pain and addiction disorders. Therefore, the present review will attempt to summarize the latest relevant findings regarding the regulation and functional characteristics of the μ-δ heteromer both in vitro and in vivo.
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Affiliation(s)
| | - Lakshmi A. Devi
- Corresponding author: , Phone: (212) 241-8345; Fax: (212) 996-7214
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Purington LC, Sobczyk-Kojiro K, Pogozheva ID, Traynor JR, Mosberg HI. Development and in vitro characterization of a novel bifunctional μ-agonist/δ-antagonist opioid tetrapeptide. ACS Chem Biol 2011; 6:1375-81. [PMID: 21958158 DOI: 10.1021/cb200263q] [Citation(s) in RCA: 32] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
The development of tolerance to and dependence on opioid analgesics greatly reduces their long-term usefulness. Previous studies have demonstrated that co-administration of a μ-opioid receptor (MOR) agonist and δ-opioid receptor (DOR) antagonist can decrease MOR agonist-induced tolerance and dependence development after chronic exposure. Clinically, a single ligand displaying multiple efficacies (e.g., MOR agonism concurrently with DOR antagonism) would be of increased value over two drugs administered simultaneously. Guided by modeling of receptor-ligand complexes we have developed a series of potent non-selective opioid tetrapeptides that have differing efficacy at MOR and DOR. In particular, our lead peptide (KSK-103) binds with equal affinity to MOR and DOR but acts as a MOR agonist with similar efficacy but greater potency than morphine and a DOR antagonist in cellular assays measuring both G protein stimulation and adenylyl cyclase inhibition.
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Affiliation(s)
- Lauren C. Purington
- Medical School and College of Pharmacy, Departments of †Pharmacology and ‡Medicinal Chemistry, and §Substance Abuse Research Center, University of Michigan, Ann Arbor, Michigan 48109, United States
| | - Katarzyna Sobczyk-Kojiro
- Medical School and College of Pharmacy, Departments of †Pharmacology and ‡Medicinal Chemistry, and §Substance Abuse Research Center, University of Michigan, Ann Arbor, Michigan 48109, United States
| | - Irina D. Pogozheva
- Medical School and College of Pharmacy, Departments of †Pharmacology and ‡Medicinal Chemistry, and §Substance Abuse Research Center, University of Michigan, Ann Arbor, Michigan 48109, United States
| | - John R. Traynor
- Medical School and College of Pharmacy, Departments of †Pharmacology and ‡Medicinal Chemistry, and §Substance Abuse Research Center, University of Michigan, Ann Arbor, Michigan 48109, United States
| | - Henry I. Mosberg
- Medical School and College of Pharmacy, Departments of †Pharmacology and ‡Medicinal Chemistry, and §Substance Abuse Research Center, University of Michigan, Ann Arbor, Michigan 48109, United States
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He SQ, Zhang ZN, Guan JS, Liu HR, Zhao B, Wang HB, Li Q, Yang H, Luo J, Li ZY, Wang Q, Lu YJ, Bao L, Zhang X. Facilitation of μ-opioid receptor activity by preventing δ-opioid receptor-mediated codegradation. Neuron 2011; 69:120-31. [PMID: 21220103 DOI: 10.1016/j.neuron.2010.12.001] [Citation(s) in RCA: 168] [Impact Index Per Article: 12.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 10/26/2010] [Indexed: 12/31/2022]
Abstract
δ-opioid receptors (DORs) form heteromers with μ-opioid receptors (MORs) and negatively regulate MOR-mediated spinal analgesia. However, the underlying mechanism remains largely unclear. The present study shows that the activity of MORs can be enhanced by preventing MORs from DOR-mediated codegradation. Treatment with DOR-specific agonists led to endocytosis of both DORs and MORs. These receptors were further processed for ubiquitination and lysosomal degradation, resulting in a reduction of surface MORs. Such effects were attenuated by treatment with an interfering peptide containing the first transmembrane domain of MOR (MOR(TM1)), which interacted with DORs and disrupted the MOR/DOR interaction. Furthermore, the systemically applied fusion protein consisting of MOR(TM1) and TAT at the C terminus could disrupt the MOR/DOR interaction in the mouse spinal cord, enhance the morphine analgesia, and reduce the antinociceptive tolerance to morphine. Thus, dissociation of MORs from DORs in the cell membrane is a potential strategy to improve opioid analgesic therapies.
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Affiliation(s)
- Shao-Qiu He
- Shanghai Institutes for Biological Sciences, Chinese Academy of Sciences, Shanghai 200031, People's Republic of China
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Williams TJ, Torres-Reveron A, Chapleau JD, Milner TA. Hormonal regulation of delta opioid receptor immunoreactivity in interneurons and pyramidal cells in the rat hippocampus. Neurobiol Learn Mem 2011; 95:206-20. [PMID: 21224009 DOI: 10.1016/j.nlm.2011.01.002] [Citation(s) in RCA: 33] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/21/2010] [Revised: 01/04/2011] [Accepted: 01/04/2011] [Indexed: 10/18/2022]
Abstract
Clinical and preclinical studies indicate that women and men differ in relapse vulnerability to drug-seeking behavior during abstinence periods. As relapse is frequently triggered by exposure of the recovered addict to objects previously associated with drug use and the formation of these associations requires memory systems engaged by the hippocampal formation (HF), studies exploring ovarian hormone modulation of hippocampal function are warranted. Previous studies revealed that ovarian steroids alter endogenous opioid peptide levels and trafficking of mu opioid receptors in the HF, suggesting cooperative interaction between opioids and estrogens in modulating hippocampal excitability. However, whether ovarian steroids affect the levels or trafficking of delta opioid receptors (DORs) in the HF is unknown. Here, hippocampal sections of adult male and normal cycling female Sprague-Dawley rats were processed for quantitative immunoperoxidase light microscopy and dual label fluorescence or immunoelectron microscopy using antisera directed against the DOR and neuropeptide Y (NPY). Consistent with previous studies in males, DOR-immunoreactivity (-ir) localized to select interneurons and principal cells in the female HF. In comparison to males, females, regardless of estrous cycle phase, show reduced DOR-ir in the granule cell layer of the dentate gyrus and proestrus (high estrogen) females, in particular, display reduced DOR-ir in the CA1 pyramidal cell layer. Ultrastructural analysis of DOR-labeled profiles in CA1 revealed that while females generally show fewer DORs in the distal apical dendrites of pyramidal cells, proestrus females, in particular, exhibit DOR internalization and trafficking towards the soma. Dual label studies revealed that DORs are found in NPY-labeled interneurons in the hilus, CA3, and CA1. While DOR colocalization frequency in NPY-labeled neuron somata was similar between animals in the hilus, proestrus females had fewer NPY-labeled neurons that co-labeled with DOR in stratum oriens of CA1 and CA3 when compared to males. Ultrastructural analysis of NPY-labeled axon terminals within stratum radiatum of CA1 revealed that NPY-labeled axon terminals contain DORs that are frequently found at or near the plasma membrane. As no differences were noted by sex or estrous cycle phase, DOR activation on NPY-labeled axon terminals would inhibit GABA release probability equally in males and females. Taken together, these findings suggest that ovarian steroids can impact hippocampal function through direct effects on DOR levels and trafficking in principal cells and broad indirect effects through reductions in DOR-ir in NPY-labeled interneurons, particularly in CA1.
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Affiliation(s)
- Tanya J Williams
- Department of Neurology and Neuroscience, Weill Cornell Medical College, New York, NY 10065, USA.
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Dubois D, Gendron L. Delta opioid receptor-mediated analgesia is not altered in preprotachykinin A knockout mice. Eur J Neurosci 2010; 32:1921-9. [DOI: 10.1111/j.1460-9568.2010.07466.x] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/24/2022]
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Dissociation of μ- and δ-opioid inhibition of glutamatergic synaptic transmission in superficial dorsal horn. Mol Pain 2010; 6:71. [PMID: 20977770 PMCID: PMC2987996 DOI: 10.1186/1744-8069-6-71] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/23/2010] [Accepted: 10/26/2010] [Indexed: 01/08/2023] Open
Abstract
BACKGROUND There is anatomical and behavioural evidence that μ- and δ-opioid receptors modulate distinct nociceptive modalities within the superficial dorsal horn. The aim of the present study was to examine whether μ- and δ-opioid receptor activation differentially modulates TRP sensitive inputs to neurons within the superficial dorsal horn. To do this, whole cell patch clamp recordings were made from lamina I - II neurons in rat spinal cord slices in vitro to examine the effect of opioids on TRP agonist-enhanced glutamatergic spontaneous miniature excitatory postsynaptic currents (EPSCs). RESULTS Under basal conditions the μ-opioid agonist DAMGO (3 μM) reduced the rate of miniature EPSCs in 68% of neurons, while the δ- and κ-opioid agonists deltorphin-II (300 nM) and U69593 (300 nM) did so in 13 - 17% of neurons tested. The TRP agonists menthol (400 μM) and icilin (100 μM) both produced a Ca2+-dependent increase in miniature EPSC rate which was unaffected by the voltage dependent calcium channel (VDCC) blocker Cd2+. The proportion of neurons in which deltorphin-II reduced the miniature EPSC rate was enhanced in the presence of icilin (83%), but not menthol (0%). By contrast, the proportion of DAMGO and U69593 responders was unaltered in the presence of menthol (57%, 0%), or icilin (57%, 17%). CONCLUSIONS These findings demonstrate that δ-opioid receptor activation selectively inhibits inputs activated by icilin, whereas μ-opioid receptor activation has a more widespread effect on synaptic inputs to neurons in the superficial dorsal horn. These findings suggest that δ-opioids may provide a novel analgesic approach for specific, TRPA1-like mediated pain modalities.
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Abstract
The chemokine receptor CXCR4 and the μ-opioid receptor (MOR) are G-protein-coupled receptors that are essential for normal function of the nervous and immune systems. Several studies have suggested that MOR is a key regulator of CXCR4 in the brain; however, the molecular basis of the opioid-chemokine interaction is not fully understood, and it may involve different mechanisms in neuronal and glial cells. Our previous studies demonstrated that MOR stimulation specifically upregulates the protein ferritin heavy chain - an inhibitor of CXCR4 - in neurons, and suggested that additional mechanisms could be operative in glia. In this study, we investigated CXCR4 function in brains and astroglial cultures deprived of MOR. Reduced coupling of CXCR4 to G-proteins was found in brain slices and tissue homogenates of MOR(-/-) mice as compared with wild-type controls. CXCR4-induced signaling was also reduced in glial cultures from MOR(-/-) mice, as shown by analysis of CXCR4 downstream targets (Akt and ERK1/2). Pharmacological studies with δ-opioid receptor (DOR)-specific ligands suggested that DOR-CXCR4 interactions are implicated in the inhibition of CXCR4 in MOR-deficient cells both in vitro and in vivo. Moreover, increased CXCR4/DOR co-immunoprecipitation was found in brain tissue and cultured glia from MOR(-/-) mice. Importantly, CXCR4 function was restored by pretreatment with a DOR antagonist. Overall, these findings indicate that DOR plays a crucial role in the regulation of CXCR4 in glia, probably via silent receptor heterodimers. The data also suggest that the opiate system interferes with normal CXCR4 function in different ways, depending on receptor subtypes.
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MESH Headings
- Animals
- Blotting, Western
- Brain/metabolism
- Cells, Cultured
- Extracellular Signal-Regulated MAP Kinases/metabolism
- Immunoprecipitation
- Mice
- Mice, Knockout
- Neuroglia/metabolism
- Neurons/metabolism
- Proto-Oncogene Proteins c-akt/metabolism
- Receptors, CXCR4/metabolism
- Receptors, Opioid, delta/metabolism
- Receptors, Opioid, mu/genetics
- Receptors, Opioid, mu/metabolism
- Reverse Transcriptase Polymerase Chain Reaction
- Signal Transduction
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Affiliation(s)
- Silvia Burbassi
- Department of Pharmacology and Physiology, Drexel University College of Medicine, Philadelphia, PA
| | - Rajarshi Sengupta
- Department of Pharmacology and Physiology, Drexel University College of Medicine, Philadelphia, PA
| | - Olimpia Meucci
- Department of Pharmacology and Physiology, Drexel University College of Medicine, Philadelphia, PA
- Department of Microbiology and Immunology, Drexel University College of Medicine, Philadelphia, PA
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Berger AC, Whistler JL. How to design an opioid drug that causes reduced tolerance and dependence. Ann Neurol 2010; 67:559-69. [PMID: 20437553 DOI: 10.1002/ana.22002] [Citation(s) in RCA: 48] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/19/2023]
Abstract
Mu opioid receptor (MOR) agonists such as morphine are extremely effective treatments for acute pain. In the setting of chronic pain, however, their long-term utility is limited by the development of tolerance and physical dependence. Drug companies have tried to overcome these problems by simply "dialing up" signal transduction at the receptor, designing more potent and efficacious agonists and more long-lasting formulations. Neither of these strategies has proven to be successful, however, because the net amount of signal transduction, particularly over extended periods of drug use, is a product of much more than the pharmacokinetic properties of potency, efficacy, half-life, and bioavailability, the mainstays of traditional pharmaceutical screening. Both the quantity and quality of signal transduction are influenced by many regulated processes, including receptor desensitization, trafficking, and oligomerization. Importantly, the efficiency with which an agonist first stimulates signal transduction is not necessarily related to the efficiency with which it stimulates these other processes. Here we describe recent findings that suggest MOR agonists with diminished propensity to cause tolerance and dependence can be identified by screening drugs for the ability to induce MOR desensitization, endocytosis, and recycling. We also discuss preliminary evidence that heteromers of the delta opioid receptor and the MOR are pronociceptive, and that drugs that spare such heteromers may also induce reduced tolerance.
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Affiliation(s)
- Amy Chang Berger
- Department of Neurology, University of California, San Francisco, Ernest Gallo Clinic and Research Center, Emeryville, CA, USA
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Trigo JM, Martin-García E, Berrendero F, Robledo P, Maldonado R. The endogenous opioid system: a common substrate in drug addiction. Drug Alcohol Depend 2010; 108:183-94. [PMID: 19945803 DOI: 10.1016/j.drugalcdep.2009.10.011] [Citation(s) in RCA: 146] [Impact Index Per Article: 10.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 06/23/2009] [Revised: 09/30/2009] [Accepted: 10/28/2009] [Indexed: 12/17/2022]
Abstract
Drug addiction is a chronic brain disorder leading to complex adaptive changes within the brain reward circuits that involve several neurotransmitters. One of the neurochemical systems that plays a pivotal role in different aspects of addiction is the endogenous opioid system (EOS). Opioid receptors and endogenous opioid peptides are largely distributed in the mesolimbic system and modulate dopaminergic activity within these reward circuits. Chronic exposure to the different prototypical drugs of abuse, including opioids, alcohol, nicotine, psychostimulants and cannabinoids has been reported to produce significant alterations within the EOS, which seem to play an important role in the development of the addictive process. In this review, we will describe the adaptive changes produced by different drugs of abuse on the EOS, and the current knowledge about the contribution of each component of this neurobiological system to their addictive properties.
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Affiliation(s)
- José Manuel Trigo
- Laboratori de Neurofarmacologia, Departament de Ciències Experimentals i de la Salut, Universitat Pompeu Fabra, PRBB, Barcelona, Spain
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Molinari P, Vezzi V, Sbraccia M, Grò C, Riitano D, Ambrosio C, Casella I, Costa T. Morphine-like opiates selectively antagonize receptor-arrestin interactions. J Biol Chem 2010; 285:12522-35. [PMID: 20189994 DOI: 10.1074/jbc.m109.059410] [Citation(s) in RCA: 88] [Impact Index Per Article: 6.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/11/2022] Open
Abstract
The addictive potential of opioids may be related to their differential ability to induce G protein signaling and endocytosis. We compared the ability of 20 ligands (sampled from the main chemical classes of opioids) to promote the association of mu and delta receptors with G protein or beta-arrestin 2. Receptor-arrestin binding was monitored by bioluminescence resonance energy transfer (BRET) in intact cells, where pertussis toxin experiments indicated that the interaction was minimally affected by receptor signaling. To assess receptor-G protein coupling without competition from arrestins, we employed a cell-free BRET assay using membranes isolated from cells expressing luminescent receptors and fluorescent Gbeta(1). In this system, the agonist-induced enhancement of BRET (indicating shortening of distance between the two proteins) was G alpha-mediated (as shown by sensitivity to pertussis toxin and guanine nucleotides) and yielded data consistent with the known pharmacology of the ligands. We found marked differences of efficacy for G protein and arrestin, with a pattern suggesting more restrictive structural requirements for arrestin efficacy. The analysis of such differences identified a subset of structures showing a marked discrepancy between efficacies for G protein and arrestin. Addictive opiates like morphine and oxymorphone exhibited large differences both at delta and mu receptors. Thus, they were effective agonists for G protein coupling but acted as competitive enkephalins antagonists (delta) or partial agonists (mu) for arrestin. This arrestin-selective antagonism resulted in inhibition of short and long term events mediated by arrestin, such as rapid receptor internalization and down-regulation.
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Affiliation(s)
- Paola Molinari
- Department of Pharmacology, Istituto Superiore di Sanità, Rome 00161, Italy
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