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Kelly E, Conibear A, Henderson G. Biased Agonism: Lessons from Studies of Opioid Receptor Agonists. Annu Rev Pharmacol Toxicol 2023; 63:491-515. [PMID: 36170657 DOI: 10.1146/annurev-pharmtox-052120-091058] [Citation(s) in RCA: 19] [Impact Index Per Article: 19.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/25/2023]
Abstract
In ligand bias different agonist drugs are thought to produce distinct signaling outputs when activating the same receptor. If these signaling outputs mediate therapeutic versus adverse drug effects, then agonists that selectively activate the therapeutic signaling pathway would be extremely beneficial. It has long been thought that μ-opioid receptor agonists that selectively activate G protein- over β-arrestin-dependent signaling pathways would produce effective analgesia without the adverse effects such as respiratory depression. However, more recent data indicate that most of the therapeutic and adverse effects of agonist-induced activation of the μ-opioid receptor are actually mediated by the G protein-dependent signaling pathway, and that a number of drugs described as G protein biased in fact may not be biased, but instead may be low-intrinsic-efficacy agonists. In this review we discuss the current state of the field of bias at the μ-opioid receptor and other opioid receptor subtypes.
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Affiliation(s)
- Eamonn Kelly
- School of Physiology, Pharmacology and Neuroscience, University of Bristol, Bristol, United Kingdom;
| | - Alexandra Conibear
- School of Physiology, Pharmacology and Neuroscience, University of Bristol, Bristol, United Kingdom;
| | - Graeme Henderson
- School of Physiology, Pharmacology and Neuroscience, University of Bristol, Bristol, United Kingdom;
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2
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Min X, Sun N, Wang S, Zhang X, Kim KM. Sequestration of Gβγ by deubiquitinated arrestins into the nucleus as a novel desensitization mechanism of G protein-coupled receptors. Cell Commun Signal 2023; 21:11. [PMID: 36658650 PMCID: PMC9854190 DOI: 10.1186/s12964-022-01013-z] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/26/2022] [Accepted: 12/10/2022] [Indexed: 01/21/2023] Open
Abstract
BACKGROUND Desensitization of G protein-coupled receptors (GPCRs) refers to a rapid attenuation of responsiveness that occurs with repeated or continuous exposure to agonists. GRK-mediated phosphorylation and subsequent binding with arrestins in the activated receptor cytoplasmic cavity in competition with G proteins has been suggested as the conventional mechanism of desensitization. Along with widely accepted conventional mechanism of desensitization, studies of various GPCRs including dopamine D2-like receptors (D2R, D3R, D4R) have suggested the existence of another desensitization mechanism. In this study, loss-of-function approaches and D2-like receptor mutants that display different desensitization properties were used to elucidate the molecular mechanisms responsible for desensitization. RESULTS Desensitization development entailed the signaling cascade composed of Src, PDK1, and Akt, the latter of which in turn interacted with USP33, an arrestin deubiquitinase, to promote arrestin deubiquitination. The deubiquitinated arrestin subsequently formed a complex with Gβγ and translocated to the nucleus via an importin complex, wherein it sequestered Gβγ from the receptor and Gα, thereby attenuating receptor signaling. As in D2-like receptors, both USP33 and importin β1 were involved in the desensitization of the β2 adrenoceptor. CONCLUSIONS In addition to the conventional mechanism of desensitization, which occurs on the plasma membrane and in the cytosol, this study provides a new insight that another desensitization pathway in which nuclear trafficking plays a critical role is operating. It is plausible that multiple, complementary desensitization measures are in place to properly induce desensitization depending on receptor characteristics or the surrounding environment. Video Abstract.
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Affiliation(s)
- Xiao Min
- grid.14005.300000 0001 0356 9399Department of Pharmacology, College of Pharmacy, Chonnam National University, Gwangju, 61186 Republic of Korea
| | - Ningning Sun
- grid.14005.300000 0001 0356 9399Department of Pharmacology, College of Pharmacy, Chonnam National University, Gwangju, 61186 Republic of Korea
| | - Shujie Wang
- grid.14005.300000 0001 0356 9399Department of Pharmacology, College of Pharmacy, Chonnam National University, Gwangju, 61186 Republic of Korea
| | - Xiaohan Zhang
- grid.14005.300000 0001 0356 9399Department of Pharmacology, College of Pharmacy, Chonnam National University, Gwangju, 61186 Republic of Korea ,grid.443382.a0000 0004 1804 268XCollege of Pharmaceutical Sciences, Guizhou University, Guiyang, 550025 Guizhou China
| | - Kyeong-Man Kim
- grid.14005.300000 0001 0356 9399Department of Pharmacology, College of Pharmacy, Chonnam National University, Gwangju, 61186 Republic of Korea
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3
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Zhang J, Song C, Dai J, Li L, Yang X, Chen Z. Mechanism of opioid addiction and its intervention therapy: Focusing on the reward circuitry and mu-opioid receptor. MedComm (Beijing) 2022; 3:e148. [PMID: 35774845 PMCID: PMC9218544 DOI: 10.1002/mco2.148] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/25/2021] [Revised: 05/03/2022] [Accepted: 05/07/2022] [Indexed: 11/09/2022] Open
Abstract
Opioid abuse and addiction have become a global pandemic, posing tremendous health and social burdens. The rewarding effects and the occurrence of withdrawal symptoms are the two mainstays of opioid addiction. Mu-opioid receptors (MORs), a member of opioid receptors, play important roles in opioid addiction, mediating both the rewarding effects of opioids and opioid withdrawal syndrome (OWS). The underlying mechanism of MOR-mediated opioid rewarding effects and withdrawal syndrome is of vital importance to understand the nature of opioid addiction and also provides theoretical basis for targeting MORs to treat drug addiction. In this review, we first briefly introduce the basic concepts of MORs, including their structure, distribution in the nervous system, endogenous ligands, and functional characteristics. We focused on the brain circuitry and molecular mechanism of MORs-mediated opioid reward and withdrawal. The neuroanatomical and functional elements of the neural circuitry of the reward system underlying opioid addiction were thoroughly discussed, and the roles of MOR within the reward circuitry were also elaborated. Furthermore, we interrogated the roles of MORs in OWS, along with the structural basis and molecular adaptions of MORs-mediated withdrawal syndrome. Finally, current treatment strategies for opioid addiction targeting MORs were also presented.
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Affiliation(s)
- Jia‐Jia Zhang
- National Translational Science Center for Molecular Medicine & Department of Cell BiologyThe Fourth Military Medical UniversityXi'anChina
| | - Chang‐Geng Song
- Department of NeurologyXijing HospitalThe Fourth Military Medical UniversityXi'anChina
| | - Ji‐Min Dai
- Department of Hepatobiliary SurgeryXijing HospitalThe Fourth Military Medical UniversityXi'anChina
| | - Ling Li
- National Translational Science Center for Molecular Medicine & Department of Cell BiologyThe Fourth Military Medical UniversityXi'anChina
| | - Xiang‐Min Yang
- National Translational Science Center for Molecular Medicine & Department of Cell BiologyThe Fourth Military Medical UniversityXi'anChina
| | - Zhi‐Nan Chen
- National Translational Science Center for Molecular Medicine & Department of Cell BiologyThe Fourth Military Medical UniversityXi'anChina
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4
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Manandhar P, Connor M, Santiago M. Tapentadol shows lower intrinsic efficacy at µ receptor than morphine and oxycodone. Pharmacol Res Perspect 2022; 10:e00921. [PMID: 35084120 PMCID: PMC8929351 DOI: 10.1002/prp2.921] [Citation(s) in RCA: 4] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/17/2021] [Revised: 12/23/2021] [Accepted: 12/27/2021] [Indexed: 12/12/2022] Open
Abstract
Tapentadol is a centrally acting analgesic with a dual mechanism of action. It acts as an agonist at the µ receptor and inhibitor of noradrenaline reuptake. Clinical trials suggest similar analgesic efficacy of tapentadol, oxycodone, and morphine in acute and chronic pain. Given the limited information about the molecular actions of tapentadol at the µ receptor, we investigated the intrinsic efficacy of tapentadol and compared it with other opioids. β-chlornaltrexamine (β-CNA, 100 nM, 20 min) was used to deplete spare receptors in AtT20 cells stably transfected with human µ receptor wild-type (WT). Opioid-mediated changes in membrane potential were measured in real-time using a membrane potential-sensitive fluorescent dye. Using Black and Leff's operational model, intrinsic efficacy relative to DAMGO was calculated for each opioid. Tapentadol (0.05 ± 0.01) activated the GIRK channel with lesser intrinsic efficacy than morphine (0.17 ± 0.02) and oxycodone (0.16 ± 0.02). We further assessed the signaling of tapentadol in the common µ receptor variants (N40D and A6V) which are associated with altered receptor signaling. We found no difference in the response of tapentadol between these receptor variants.
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Affiliation(s)
- Preeti Manandhar
- Macquarie Medical SchoolMacquarie UniversitySydneyNew South WalesAustralia
| | - Mark Connor
- Macquarie Medical SchoolMacquarie UniversitySydneyNew South WalesAustralia
| | - Marina Santiago
- Macquarie Medical SchoolMacquarie UniversitySydneyNew South WalesAustralia
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5
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Mechanistic diversity involved in the desensitization of G protein-coupled receptors. Arch Pharm Res 2021; 44:342-353. [PMID: 33761113 DOI: 10.1007/s12272-021-01320-y] [Citation(s) in RCA: 11] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/10/2020] [Accepted: 03/14/2021] [Indexed: 01/14/2023]
Abstract
The desensitization of G protein-coupled receptors (GPCRs), which involves rapid loss of responsiveness due to repeated or chronic exposure to agonists, can occur through various mechanisms at different levels of signaling pathways. In this review, the mechanisms of GPCR desensitization are classified according to their occurrence at the receptor level and downstream to the receptor. The desensitization at the receptor level occurs in a phosphorylation-dependent manner, wherein the activated receptors are phosphorylated by GPCR kinases (GRKs), thereby increasing their affinities for arrestins. Arrestins bind to receptors through the cavity on the cytoplasmic region of heptahelical domains and interfere with the binding and activation of G-protein. Diverse mechanisms are involved in the desensitization that occurs downstream of the receptor. Some of these include the sequestration of G proteins, such as Gq and Gi/o by GRK2/3 and deubiquitinated arrestins, respectively. Mechanistically, GRK2/3 attenuates GPCR signaling by sequestering the Gα subunits of the Gq family and Gβγ via regulators of G protein signaling and pleckstrin homology domains, respectively. Moreover, studies on Gi/o-coupled D2-like receptors have reported that arrestins are deubiquitinated under desensitization condition and form a stable complex with Gβγ, thereby preventing them from coupling with Gα and the receptor, eventually leading to receptor signaling inhibition. Notably, the desensitization mechanism that involves arrestin deubiquitination is interesting; however, this is a new mechanism and needs to be explored further.
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6
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Ruland JG, Kirchhofer SB, Klindert S, Bailey CP, Bünemann M. Voltage modulates the effect of μ-receptor activation in a ligand-dependent manner. Br J Pharmacol 2020; 177:3489-3504. [PMID: 32297669 PMCID: PMC7348086 DOI: 10.1111/bph.15070] [Citation(s) in RCA: 14] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/17/2019] [Revised: 03/16/2020] [Accepted: 03/30/2020] [Indexed: 12/28/2022] Open
Abstract
BACKGROUND AND PURPOSE Various GPCRs have been described as being modulated in a voltage-dependent manner. Opioid analgesics act via activation of μ receptors in various neurons. As neurons are exposed to large changes in membrane potential, we were interested in studying the effects of depolarization on μ receptor signalling. EXPERIMENTAL APPROACH We investigated potential voltage sensitivity of μ receptors in heterologous expression systems (HEK293T cells) using electrophysiology in combination with Förster resonance energy transfer-based assays. Depolarization-induced changes in signalling were also tested in physiological rat tissue containing locus coeruleus neurons. We applied depolarization steps across the physiological range of membrane potentials. KEY RESULTS Studying μ receptor function and signalling in cells, we discovered that morphine-induced signalling was strongly dependent on the membrane potential (VM ). This became apparent at the level of G-protein activation, G-protein coupled inwardly rectifying potassium channel (Kir 3.X) currents and binding of GPCR kinases and arrestin3 to μ receptors by a robust increase in signalling upon membrane depolarization. The pronounced voltage sensitivity of morphine-induced μ receptor activation was also observed at the level of Kir 3.X currents in rat locus coeruleus neurons. The efficacy of peptide ligands to activate μ receptors was not (Met-enkephalin) or only moderately ([D-Ala2 , N-Me-Phe4 , Gly5 -ol]-enkephalin) enhanced upon depolarization. In contrast, depolarization reduced the ability of the analgesic fentanyl to activate μ receptors. CONCLUSION AND IMPLICATIONS Our results indicate a strong ligand-dependent modulation of μ receptor activity by the membrane potential, suggesting preferential activity of morphine in neurons with high neuronal activity.
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Affiliation(s)
- Julia G Ruland
- Department of Pharmacology and Clinical Pharmacy, Philipps-University, Marburg, Germany
| | - Sina B Kirchhofer
- Department of Pharmacology and Clinical Pharmacy, Philipps-University, Marburg, Germany
| | - Sebastian Klindert
- Department of Pharmacology and Clinical Pharmacy, Philipps-University, Marburg, Germany.,Department of Pharmacy and Pharmacology, University of Bath, Bath, UK
| | - Chris P Bailey
- Department of Pharmacy and Pharmacology, University of Bath, Bath, UK
| | - Moritz Bünemann
- Department of Pharmacology and Clinical Pharmacy, Philipps-University, Marburg, Germany
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7
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Hood LE, Leyrer-Jackson JM, Olive MF. Pharmacotherapeutic management of co-morbid alcohol and opioid use. Expert Opin Pharmacother 2020; 21:823-839. [PMID: 32103695 PMCID: PMC7239727 DOI: 10.1080/14656566.2020.1732349] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/21/2019] [Accepted: 02/17/2020] [Indexed: 12/12/2022]
Abstract
Opioid use disorder (OUD) and alcohol use disorder (AUD) are two highly prevalent substance-related disorders worldwide. Co-use of the substances is also quite prevalent, yet there are no pharmacological treatment approaches specifically designed to treat co-morbid OUD and AUD. Here, the authors critically summarize OUD, AUD and opioid/alcohol co-use and their current pharmacotherapies for treatment. They also review the mechanisms of action of opioids and alcohol within the brain reward circuitry and discuss potential combined mechanisms of action and resulting neuroadaptations. Pharmacotherapies that aim to treat AUD or OUD that may be beneficial in the treatment of co-use are also highlighted. Preclinical models assessing alcohol and opioid co-use remain sparse. Lasting neuroadaptations in brain reward circuits caused by co-use of alcohol and opioids remains largely understudied. In order to fully understand the neurobiological underpinnings of alcohol and opioid co-use and develop efficacious pharmacotherapies, the preclinical field must expand its current experimental paradigms of 'single drug' use to encompass polysubstance use. Such studies will provide insights on the neural alterations induced by opioid and alcohol co-use, and may help develop novel pharmacotherapies for individuals with co-occurring alcohol and opioid use disorders.
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Affiliation(s)
- Lauren E. Hood
- Department of Psychology, Arizona State University, Tempe, Arizona, USA
| | | | - M. Foster Olive
- Department of Psychology, Arizona State University, Tempe, Arizona, USA
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8
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Abstract
Opioids are very potent and efficacious drugs, traditionally used for both acute and chronic pain conditions. However, the use of opioids is frequently associated with the occurrence of adverse effects or clinical problems. Other than adverse effects and dependence, the development of tolerance is a significant problem, as it requires increased opioid drug doses to achieve the same effect. Mechanisms of opioid tolerance include drug-induced adaptations or allostatic changes at the cellular, circuitry, and system levels. Dose escalation in long-term opioid therapy might cause opioid-induced hyperalgesia (OIH), which is a state of hypersensitivity to painful stimuli associated with opioid therapy, resulting in exacerbation of pain sensation rather than relief of pain. Various strategies may provide extra-opioid analgesia. There are drugs that may produce independent analgesic effects. A tailored treatment provided by skilled personnel, in accordance with the individual condition, is mandatory. Any treatment aimed at reducing opioid consumption may be indicated in these circumstances. Interventional techniques able to decrease the pain input may allow a decrease in the opioid dose, thus reverting the mechanisms producing tolerance of OIH. Intrathecal therapy with local anesthetics and a sympathetic block are the most common techniques utilized in these circumstances.
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Affiliation(s)
- Sebastiano Mercadante
- Main Regional Center of Supportive/Palliative Care, La Maddalena Cancer Center, Palermo, Italy. .,Palliative/Supportive Care and Rehabilitation, MD Anderson, Houston, TX, USA.
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9
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Heterodimerization of Mu Opioid Receptor Protomer with Dopamine D 2 Receptor Modulates Agonist-Induced Internalization of Mu Opioid Receptor. Biomolecules 2019; 9:biom9080368. [PMID: 31416253 PMCID: PMC6722706 DOI: 10.3390/biom9080368] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/12/2019] [Revised: 08/12/2019] [Accepted: 08/13/2019] [Indexed: 02/07/2023] Open
Abstract
The interplay between the dopamine (DA) and opioid systems in the brain is known to modulate the additive effects of substances of abuse. On one hand, opioids serve mankind by their analgesic properties, which are mediated via the mu opioid receptor (MOR), a Class A G protein-coupled receptor (GPCR), but on the other hand, they pose a potential threat by causing undesired side effects such as tolerance and dependence, for which the exact molecular mechanism is still unknown. Using human embryonic kidney 293T (HEK 293T) and HeLa cells transfected with MOR and the dopamine D2 receptor (D2R), we demonstrate that these receptors heterodimerize, using an array of biochemical and biophysical techniques such as coimmunoprecipitation (co-IP), bioluminescence resonance energy transfer (BRET1), Fӧrster resonance energy transfer (FRET), and functional complementation of a split luciferase. Furthermore, live cell imaging revealed that D2LR, when coexpressed with MOR, slowed down internalization of MOR, following activation with the MOR agonist [D-Ala2, N-MePhe4, Gly-ol]-enkephalin (DAMGO).
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10
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Zjawiony JK, Machado AS, Menegatti R, Ghedini PC, Costa EA, Pedrino GR, Lukas SE, Franco OL, Silva ON, Fajemiroye JO. Cutting-Edge Search for Safer Opioid Pain Relief: Retrospective Review of Salvinorin A and Its Analogs. Front Psychiatry 2019; 10:157. [PMID: 30971961 PMCID: PMC6445891 DOI: 10.3389/fpsyt.2019.00157] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 07/22/2018] [Accepted: 03/04/2019] [Indexed: 12/21/2022] Open
Abstract
Over the years, pain has contributed to low life quality, poor health, and economic loss. Opioids are very effective analgesic drugs for treating mild, moderate, or severe pain. Therapeutic application of opioids has been limited by short and long-term side effects. These side effects and opioid-overuse crisis has intensified interest in the search for new molecular targets and drugs. The present review focuses on salvinorin A and its analogs with the aim of exploring their structural and pharmacological profiles as clues for the development of safer analgesics. Ethnopharmacological reports and growing preclinical data have demonstrated the antinociceptive effect of salvinorin A and some of its analogs. The pharmacology of analogs modified at C-2 dominates the literature when compared to the ones from other positions. The distinctive binding affinity of these analogs seems to correlate with their chemical structure and in vivo antinociceptive effects. The high susceptibility of salvinorin A to chemical modification makes it an important pharmacological tool for cellular probing and developing analogs with promising analgesic effects. Additional research is still needed to draw reliable conclusions on the therapeutic potential of salvinorin A and its analogs.
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Affiliation(s)
- Jordan K Zjawiony
- Division of Pharmacognosy, Department of BioMolecular Sciences, School of Pharmacy, Research Institute of Pharmaceutical Sciences, University of Mississippi, University, MS, United States
| | - Antônio S Machado
- Laboratory of Medicinal Pharmaceutical Chemistry, Faculty of Pharmacy, Universidade Federal de Goiás, Goiânia, Brazil
| | - Ricardo Menegatti
- Laboratory of Medicinal Pharmaceutical Chemistry, Faculty of Pharmacy, Universidade Federal de Goiás, Goiânia, Brazil
| | - Paulo C Ghedini
- Department of Pharmacology, Institute of Biological Sciences, Universidade Federal de Goiás, Goiânia, Brazil
| | - Elson A Costa
- Department of Pharmacology, Institute of Biological Sciences, Universidade Federal de Goiás, Goiânia, Brazil
| | - Gustavo R Pedrino
- Department of Physiology, Universidade Federal de Goiás, Goiânia, Brazil
| | - Scott E Lukas
- McLean Imaging Center, Harvard Medical School, McLean Hospital, Belmont, MA, United States
| | - Octávio L Franco
- S-Inova Biotech, Programa de Pós-Graduação em Biotecnologia, Universidade Católica Dom Bosco, Campo Grande, Brazil.,Centro de Análises Proteômicas e Bioquímicas, Pós-graduação em Ciências Genômicas e Biotecnologia, Universidade Católica de Brasília, Brasília, Brazil.,Programa de Pós-graduação em Patologia Molecular, Universidade de Brasília, Brasília, Brazil
| | - Osmar N Silva
- S-Inova Biotech, Programa de Pós-Graduação em Biotecnologia, Universidade Católica Dom Bosco, Campo Grande, Brazil
| | - James O Fajemiroye
- Department of Physiology, Universidade Federal de Goiás, Goiânia, Brazil.,Centro Universitário de Anápolis, Unievangélica, Anápolis, Brazil
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11
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Araldi D, Ferrari LF, Levine JD. Mu-opioid Receptor (MOR) Biased Agonists Induce Biphasic Dose-dependent Hyperalgesia and Analgesia, and Hyperalgesic Priming in the Rat. Neuroscience 2018; 394:60-71. [PMID: 30342200 DOI: 10.1016/j.neuroscience.2018.10.015] [Citation(s) in RCA: 24] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/03/2018] [Revised: 09/17/2018] [Accepted: 10/09/2018] [Indexed: 01/19/2023]
Abstract
Stimulation of the mu-opioid receptor (MOR) on nociceptors with fentanyl can produce hyperalgesia (opioid-induced hyperalgesia, OIH) and hyperalgesic priming, a model of transition to chronic pain. We investigated if local and systemic administration of biased MOR agonists (PZM21 and TRV130 [oliceridine]), which preferentially activate G-protein over β-arrestin translocation, and have been reported to minimize some opioid side effects, also produces OIH and priming. Injected intradermally (100 ng), both biased agonists induced mechanical hyperalgesia and, when injected at the same site, 5 days later, prostaglandin E2 (PGE2) produced prolonged hyperalgesia (priming). OIH and priming were both prevented by intrathecal treatment with an oligodeoxynucleotide (ODN) antisense (AS) for MOR mRNA. Agents that reverse Type I (the protein translation inhibitor cordycepin) and Type II (combination of Src and mitogen-activated protein kinase [MAPK] inhibitors) priming, or their combination, did not reverse priming induced by local administration of PZM21 or TRV130. While systemic PZM21 at higher doses (1 and 10 mg/kg) induced analgesia, lower doses (0.001, 0.01, 0.1, and 0.3 mg/kg) induced hyperalgesia; all doses induced priming. Hyperalgesia, analgesia and priming induced by systemic administration of PZM21 were also prevented by MOR AS-ODN. And, priming induced by systemic PZM21 was also not reversed by intradermal cordycepin or the combination of Src and MAPK inhibitors. Thus, maintenance of priming induced by biased MOR agonists, in the peripheral terminal of nociceptors, has a novel mechanism.
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Affiliation(s)
- Dionéia Araldi
- Departments of Medicine and Oral Surgery, and Division of Neuroscience, University of California at San Francisco, 513 Parnassus Avenue, San Francisco, CA 94143, USA.
| | - Luiz F Ferrari
- Departments of Medicine and Oral Surgery, and Division of Neuroscience, University of California at San Francisco, 513 Parnassus Avenue, San Francisco, CA 94143, USA.
| | - Jon D Levine
- Departments of Medicine and Oral Surgery, and Division of Neuroscience, University of California at San Francisco, 513 Parnassus Avenue, San Francisco, CA 94143, USA.
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12
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Miess E, Gondin AB, Yousuf A, Steinborn R, Mösslein N, Yang Y, Göldner M, Ruland JG, Bünemann M, Krasel C, Christie MJ, Halls ML, Schulz S, Canals M. Multisite phosphorylation is required for sustained interaction with GRKs and arrestins during rapid μ-opioid receptor desensitization. Sci Signal 2018; 11:11/539/eaas9609. [PMID: 30018083 DOI: 10.1126/scisignal.aas9609] [Citation(s) in RCA: 84] [Impact Index Per Article: 14.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/20/2022]
Abstract
G protein receptor kinases (GRKs) and β-arrestins are key regulators of μ-opioid receptor (MOR) signaling and trafficking. We have previously shown that high-efficacy opioids such as DAMGO stimulate a GRK2/3-mediated multisite phosphorylation of conserved C-terminal tail serine and threonine residues, which facilitates internalization of the receptor. In contrast, morphine-induced phosphorylation of MOR is limited to Ser375 and is not sufficient to drive substantial receptor internalization. We report how specific multisite phosphorylation controlled the dynamics of GRK and β-arrestin interactions with MOR and show how such phosphorylation mediated receptor desensitization. We showed that GRK2/3 was recruited more quickly than was β-arrestin to a DAMGO-activated MOR. β-Arrestin recruitment required GRK2 activity and MOR phosphorylation, but GRK recruitment also depended on the phosphorylation sites in the C-terminal tail, specifically four serine and threonine residues within the 370TREHPSTANT379 motif. Our results also suggested that other residues outside this motif participated in the initial and transient recruitment of GRK and β-arrestins. We identified two components of high-efficacy agonist desensitization of MOR: a sustained component, which required GRK2-mediated phosphorylation and a potential soluble factor, and a rapid component, which was likely mediated by GRK2 but independent of receptor phosphorylation. Elucidating these complex receptor-effector interactions represents an important step toward a mechanistic understanding of MOR desensitization that leads to the development of tolerance and dependence.
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Affiliation(s)
- Elke Miess
- Department of Pharmacology and Toxicology, Jena University Hospital-Friedrich Schiller University Jena, D-07747 Jena, Germany
| | - Arisbel B Gondin
- Drug Discovery Biology Theme, Monash Institute of Pharmaceutical Sciences, Monash University, Victoria 3052, Australia
| | - Arsalan Yousuf
- Discipline of Pharmacology, University of Sydney, New South Wales 2006, Australia
| | - Ralph Steinborn
- Department of Pharmacology and Toxicology, Jena University Hospital-Friedrich Schiller University Jena, D-07747 Jena, Germany
| | - Nadja Mösslein
- Department of Pharmacology and Toxicology, Philipps-University Marburg, D-35043 Marburg, Germany
| | - Yunshi Yang
- Department of Pharmacology and Toxicology, Philipps-University Marburg, D-35043 Marburg, Germany
| | - Martin Göldner
- Department of Pharmacology and Toxicology, Philipps-University Marburg, D-35043 Marburg, Germany
| | - Julia G Ruland
- Department of Pharmacology and Toxicology, Philipps-University Marburg, D-35043 Marburg, Germany
| | - Moritz Bünemann
- Department of Pharmacology and Toxicology, Philipps-University Marburg, D-35043 Marburg, Germany
| | - Cornelius Krasel
- Department of Pharmacology and Toxicology, Philipps-University Marburg, D-35043 Marburg, Germany
| | - MacDonald J Christie
- Discipline of Pharmacology, University of Sydney, New South Wales 2006, Australia
| | - Michelle L Halls
- Drug Discovery Biology Theme, Monash Institute of Pharmaceutical Sciences, Monash University, Victoria 3052, Australia
| | - Stefan Schulz
- Department of Pharmacology and Toxicology, Jena University Hospital-Friedrich Schiller University Jena, D-07747 Jena, Germany.
| | - Meritxell Canals
- Drug Discovery Biology Theme, Monash Institute of Pharmaceutical Sciences, Monash University, Victoria 3052, Australia.
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13
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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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14
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Lam R, Gondin AB, Canals M, Kellam B, Briddon SJ, Graham B, Scammells PJ. Fluorescently Labeled Morphine Derivatives for Bioimaging Studies. J Med Chem 2018; 61:1316-1329. [DOI: 10.1021/acs.jmedchem.7b01811] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/26/2022]
Affiliation(s)
- Raymond Lam
- School
of Pharmacy, Centre for Biomolecular Sciences, University of Nottingham, Nottingham NG7 2RD, U.K
| | - Arisbel B. Gondin
- Cell Signalling
Research Group, School of Life Sciences, Queen’s Medical Centre, University of Nottingham, Nottingham NG7 2UH, U.K
| | | | - Barrie Kellam
- School
of Pharmacy, Centre for Biomolecular Sciences, University of Nottingham, Nottingham NG7 2RD, U.K
| | - Stephen J. Briddon
- Cell Signalling
Research Group, School of Life Sciences, Queen’s Medical Centre, University of Nottingham, Nottingham NG7 2UH, U.K
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15
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T394A Mutation at the μ Opioid Receptor Blocks Opioid Tolerance and Increases Vulnerability to Heroin Self-Administration in Mice. J Neurosci 2017; 36:10392-10403. [PMID: 27707973 DOI: 10.1523/jneurosci.0603-16.2016] [Citation(s) in RCA: 16] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/23/2016] [Accepted: 08/18/2016] [Indexed: 02/07/2023] Open
Abstract
The etiology and pathophysiology underlying opioid tolerance and dependence are still unknown. Because mu opioid receptor (MOR) plays an essential role in opioid action, many vulnerability-related studies have focused on single nucleotide polymorphisms of MOR, particularly on A118G. In this study, we found that a single-point mutation at the MOR T394 phosphorylation site could be another important susceptive factor in the development of opioid tolerance and dependence in mice. T394A mutation, in which a threonine at 394 was replaced by an alanine, did not alter agonist binding to MOR and opioid analgesia, but resulted in loss of etorphine-induced MOR internalization in spinal dorsal horn neurons and opioid analgesic tolerance induced by either morphine or etorphine. In addition, this mutation also caused an increase in intravenous heroin self-administration and in nucleus accumbens dopamine response to heroin. These findings suggest that T394 phosphorylation following MOR activation causes MOR internalization and desensitization, which subsequently contributes to the development of tolerance in both opioid analgesia and opioid reward. Accordingly, T394A mutation blocks opioid tolerance and leads to an increase in brain dopamine response to opioids and in opioid-taking behavior. Thus, the T394 may serve as a new drug target for modulating opioid tolerance and the development of opioid abuse and addiction. SIGNIFICANCE STATEMENT The mechanisms underlying opioid tolerance and susceptibility to opioid addiction remain unclear. The present studies demonstrate that a single-point mutation at the T394 phosphorylation site in the C-terminal of mu opioid receptor (MOR) results in loss of opioid tolerance and enhanced vulnerability to heroin self-administration. These findings suggest that modulation of the MOR-T394 phosphorylation or dephosphorylation status may have therapeutic potential in management of pain, opioid tolerance, and opioid abuse and addiction. Accordingly, MOR-T394 mutation or polymorphisms could be a risk factor in developing opioid abuse and addiction and therefore be used as a new biomarker in prediction and prevention of opioid abuse and addiction.
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16
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Mohammad Ahmadi Soleimani S, Azizi H, Pachenari N, Mirnajafi-Zadeh J, Semnanian S. Enhancement of μ-opioid receptor desensitization by orexin-A in rat locus coeruleus neurons. Neuropeptides 2017; 63:28-36. [PMID: 28385341 DOI: 10.1016/j.npep.2017.03.004] [Citation(s) in RCA: 19] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 12/18/2016] [Revised: 03/05/2017] [Accepted: 03/22/2017] [Indexed: 11/16/2022]
Abstract
Opioids have always been used in clinical practice for pain management. However, development of tolerance to their effects following long term administration, seriously restricts further clinical use of these drugs. In this regard, μ-opioid receptor (MOR) desensitization, as an initial step in development of opioid tolerance, is of particular significance. Previous studies support the involvement of orexinergic system in development of opioid tolerance. Locus coeruleus (LC) nucleus has been shown to modulate pain and development of tolerance. Opioid receptors (particularly μ) are densely expressed within the LC. Moreover, it receives widespread orexinergic inputs and orexin type 1 receptors (OX1Rs) are also highly expressed in this brain region. In the present study, the effect of orexin-A (OXA) on met-enkephalin (ME)-induced MOR desensitization was investigated in locus coeruleus neurons of male Wistar rats (2-3weeks of age). ME (30μM), as a potent MOR agonist, was applied for 10min and the outward K+ current was recorded using whole cell patch clamp recording. The percentage of decrease in ME-induced K+ current was considered as the degree of MOR desensitization. Results indicated that OXA (100nM) enhances ME-induced MOR desensitization via affecting OX1Rs in rat locus coeruleus neurons and this effect is mediated by a protein kinase C dependent mechanism within the LC. The activity of orexinergic system might potentiate the signaling pathways underlying opioid-induced receptor desensitization.
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Affiliation(s)
| | - Hossein Azizi
- Department of Physiology, Faculty of Medical Sciences, Tarbiat Modares University, Tehran, Iran.
| | - Narges Pachenari
- Department of Physiology, Faculty of Medical Sciences, Tarbiat Modares University, Tehran, Iran
| | - Javad Mirnajafi-Zadeh
- Department of Physiology, Faculty of Medical Sciences, Tarbiat Modares University, Tehran, Iran
| | - Saeed Semnanian
- Department of Physiology, Faculty of Medical Sciences, Tarbiat Modares University, Tehran, Iran; School of Cognitive Sciences, Institute for Research in Fundamental Sciences (IPM), Tehran, Iran.
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17
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Abstract
An agonist that acts through a single receptor can activate numerous signaling pathways. Recent studies have suggested that different ligands can differentially activate these pathways by stabilizing a limited range of receptor conformations, which in turn preferentially drive different downstream signaling cascades. This concept, termed "biased signaling" represents an exciting therapeutic opportunity to target specific pathways that elicit only desired effects, while avoiding undesired effects mediated by different signaling cascades. The cannabinoid receptors CB1 and CB2 each activate multiple pathways, and evidence is emerging for bias within these pathways. This review will summarize the current evidence for biased signaling through cannabinoid receptor subtypes CB1 and CB2.
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Affiliation(s)
- Mikkel Søes Ibsen
- Department of Pharmacology, School of Medical Sciences, University of Auckland, Auckland, New Zealand
| | - Mark Connor
- Department of Biomedical Sciences, Faculty of Medicine and Health Sciences, 2 Technology Place, Macquarie University, New South Wales, Australia
| | - Michelle Glass
- Department of Pharmacology, School of Medical Sciences, University of Auckland, Auckland, New Zealand
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18
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Zhang X, Kim KM. Multifactorial Regulation of G Protein-Coupled Receptor Endocytosis. Biomol Ther (Seoul) 2017; 25:26-43. [PMID: 28035080 PMCID: PMC5207461 DOI: 10.4062/biomolther.2016.186] [Citation(s) in RCA: 29] [Impact Index Per Article: 4.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/18/2016] [Revised: 11/21/2016] [Accepted: 11/30/2016] [Indexed: 12/26/2022] Open
Abstract
Endocytosis is a process by which cells absorb extracellular materials via the inward budding of vesicles formed from the plasma membrane. Receptor-mediated endocytosis is a highly selective process where receptors with specific binding sites for extracellular molecules internalize via vesicles. G protein-coupled receptors (GPCRs) are the largest single family of plasma-membrane receptors with more than 1000 family members. But the molecular mechanisms involved in the regulation of GPCRs are believed to be highly conserved. For example, receptor phosphorylation in collaboration with β-arrestins plays major roles in desensitization and endocytosis of most GPCRs. Nevertheless, a number of subsequent studies showed that GPCR regulation, such as that by endocytosis, occurs through various pathways with a multitude of cellular components and processes. This review focused on i) functional interactions between homologous and heterologous pathways, ii) methodologies applied for determining receptor endocytosis, iii) experimental tools to determine specific endocytic routes, iv) roles of small guanosine triphosphate-binding proteins in GPCR endocytosis, and v) role of post-translational modification of the receptors in endocytosis.
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Affiliation(s)
- Xiaohan Zhang
- Pharmacology Laboratory, College of Pharmacy, Chonnam National University, Gwangju 61186, Republic of Korea
| | - Kyeong-Man Kim
- Pharmacology Laboratory, College of Pharmacy, Chonnam National University, Gwangju 61186, Republic of Korea
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19
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Abstract
Acute pain management remains a challenge in opioid dependent patients, and it has been recognised that these patients are commonly under-treated.Chronic opioid exposure leads to widespread adaptations both at cellular and synaptic level.Physical dependence is a neuropharmacological phenomenon as a result of neuroadaptation and neuroplasticity, in contrast to addiction that is both neuropharmacological and behavioural.While providing the patient's pre-existing opioid requirement, the acute pain episode should be managed using additional multimodal analgesia: non-opioid medications in combination with local anaesthetic techniques and as required, short-acting opioid titrated to effect.Patients on long term buprenorphine and methadone with acute pain episode should be continued with their maintenance therapy and an additional short-acting opioid analgesic titrated to achieve therapeutic effect.
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Affiliation(s)
- Vivek Mehta
- Consultants in Pain Medicine and Anaesthesia, Pain and Anaesthesia Research Centre, St Bartholomew's Hospital. Barts and The London NHS Trust, London, UK
| | - Richard Langford
- Consultants in Pain Medicine and Anaesthesia, Pain and Anaesthesia Research Centre, St Bartholomew's Hospital. Barts and The London NHS Trust, London, UK
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20
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Lowe JD, Sanderson HS, Cooke AE, Ostovar M, Tsisanova E, Withey SL, Chavkin C, Husbands SM, Kelly E, Henderson G, Bailey CP. Role of G Protein-Coupled Receptor Kinases 2 and 3 in μ-Opioid Receptor Desensitization and Internalization. Mol Pharmacol 2015; 88:347-56. [PMID: 26013542 DOI: 10.1124/mol.115.098293] [Citation(s) in RCA: 69] [Impact Index Per Article: 7.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/13/2015] [Accepted: 05/26/2015] [Indexed: 01/12/2023] Open
Abstract
There is ongoing debate about the role of G protein-coupled receptor kinases (GRKs) in agonist-induced desensitization of the μ-opioid receptor (MOPr) in brain neurons. In the present paper, we have used a novel membrane-permeable, small-molecule inhibitor of GRK2 and GRK3, Takeda compound 101 (Cmpd101; 3-[[[4-methyl-5-(4-pyridyl)-4H-1,2,4-triazole-3-yl] methyl] amino]-N-[2-(trifuoromethyl) benzyl] benzamidehydrochloride), to study the involvement of GRK2/3 in acute agonist-induced MOPr desensitization. We observed that Cmpd101 inhibits the desensitization of the G protein-activated inwardly-rectifying potassium current evoked by receptor-saturating concentrations of methionine-enkephalin (Met-Enk), [d-Ala(2), N-MePhe(4), Gly-ol(5)]-enkephalin (DAMGO), endomorphin-2, and morphine in rat and mouse locus coeruleus (LC) neurons. In LC neurons from GRK3 knockout mice, Met-Enk-induced desensitization was unaffected, implying a role for GRK2 in MOPr desensitization. Quantitative analysis of the loss of functional MOPrs following acute agonist exposure revealed that Cmpd101 only partially reversed MOPr desensitization. Inhibition of extracellular signal-regulated kinase 1/2, protein kinase C, c-Jun N-terminal kinase, or GRK5 did not inhibit the Cmpd101-insensitive component of desensitization. In HEK 293 cells, Cmpd101 produced almost complete inhibition of DAMGO-induced MOPr phosphorylation at Ser(375), arrestin translocation, and MOPr internalization. Our data demonstrate a role for GRK2 (and potentially also GRK3) in agonist-induced MOPr desensitization in the LC, but leave open the possibility that another, as yet unidentified, mechanism of desensitization also exists.
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Affiliation(s)
- Janet D Lowe
- School of Physiology and Pharmacology, University of Bristol, Bristol, United Kingdom (J.D.L., H.S.S., A.E.C., E.T., S.L.W., E.K., G.H.); Department of Pharmacology, University of Washington School of Medicine, Seattle, Washington (C.C.); and Department of Pharmacy and Pharmacology, University of Bath, Bath, United Kingdom (M.O., S.M.H., C.P.B.)
| | - Helen S Sanderson
- School of Physiology and Pharmacology, University of Bristol, Bristol, United Kingdom (J.D.L., H.S.S., A.E.C., E.T., S.L.W., E.K., G.H.); Department of Pharmacology, University of Washington School of Medicine, Seattle, Washington (C.C.); and Department of Pharmacy and Pharmacology, University of Bath, Bath, United Kingdom (M.O., S.M.H., C.P.B.)
| | - Alexandra E Cooke
- School of Physiology and Pharmacology, University of Bristol, Bristol, United Kingdom (J.D.L., H.S.S., A.E.C., E.T., S.L.W., E.K., G.H.); Department of Pharmacology, University of Washington School of Medicine, Seattle, Washington (C.C.); and Department of Pharmacy and Pharmacology, University of Bath, Bath, United Kingdom (M.O., S.M.H., C.P.B.)
| | - Mehrnoosh Ostovar
- School of Physiology and Pharmacology, University of Bristol, Bristol, United Kingdom (J.D.L., H.S.S., A.E.C., E.T., S.L.W., E.K., G.H.); Department of Pharmacology, University of Washington School of Medicine, Seattle, Washington (C.C.); and Department of Pharmacy and Pharmacology, University of Bath, Bath, United Kingdom (M.O., S.M.H., C.P.B.)
| | - Elena Tsisanova
- School of Physiology and Pharmacology, University of Bristol, Bristol, United Kingdom (J.D.L., H.S.S., A.E.C., E.T., S.L.W., E.K., G.H.); Department of Pharmacology, University of Washington School of Medicine, Seattle, Washington (C.C.); and Department of Pharmacy and Pharmacology, University of Bath, Bath, United Kingdom (M.O., S.M.H., C.P.B.)
| | - Sarah L Withey
- School of Physiology and Pharmacology, University of Bristol, Bristol, United Kingdom (J.D.L., H.S.S., A.E.C., E.T., S.L.W., E.K., G.H.); Department of Pharmacology, University of Washington School of Medicine, Seattle, Washington (C.C.); and Department of Pharmacy and Pharmacology, University of Bath, Bath, United Kingdom (M.O., S.M.H., C.P.B.)
| | - Charles Chavkin
- School of Physiology and Pharmacology, University of Bristol, Bristol, United Kingdom (J.D.L., H.S.S., A.E.C., E.T., S.L.W., E.K., G.H.); Department of Pharmacology, University of Washington School of Medicine, Seattle, Washington (C.C.); and Department of Pharmacy and Pharmacology, University of Bath, Bath, United Kingdom (M.O., S.M.H., C.P.B.)
| | - Stephen M Husbands
- School of Physiology and Pharmacology, University of Bristol, Bristol, United Kingdom (J.D.L., H.S.S., A.E.C., E.T., S.L.W., E.K., G.H.); Department of Pharmacology, University of Washington School of Medicine, Seattle, Washington (C.C.); and Department of Pharmacy and Pharmacology, University of Bath, Bath, United Kingdom (M.O., S.M.H., C.P.B.)
| | - Eamonn Kelly
- School of Physiology and Pharmacology, University of Bristol, Bristol, United Kingdom (J.D.L., H.S.S., A.E.C., E.T., S.L.W., E.K., G.H.); Department of Pharmacology, University of Washington School of Medicine, Seattle, Washington (C.C.); and Department of Pharmacy and Pharmacology, University of Bath, Bath, United Kingdom (M.O., S.M.H., C.P.B.)
| | - Graeme Henderson
- School of Physiology and Pharmacology, University of Bristol, Bristol, United Kingdom (J.D.L., H.S.S., A.E.C., E.T., S.L.W., E.K., G.H.); Department of Pharmacology, University of Washington School of Medicine, Seattle, Washington (C.C.); and Department of Pharmacy and Pharmacology, University of Bath, Bath, United Kingdom (M.O., S.M.H., C.P.B.)
| | - Chris P Bailey
- School of Physiology and Pharmacology, University of Bristol, Bristol, United Kingdom (J.D.L., H.S.S., A.E.C., E.T., S.L.W., E.K., G.H.); Department of Pharmacology, University of Washington School of Medicine, Seattle, Washington (C.C.); and Department of Pharmacy and Pharmacology, University of Bath, Bath, United Kingdom (M.O., S.M.H., C.P.B.)
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21
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Yousuf A, Miess E, Sianati S, Du YP, Schulz S, Christie MJ. Role of Phosphorylation Sites in Desensitization of µ-Opioid Receptor. Mol Pharmacol 2015; 88:825-35. [PMID: 25969388 DOI: 10.1124/mol.115.098244] [Citation(s) in RCA: 32] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/03/2015] [Accepted: 05/12/2015] [Indexed: 11/22/2022] Open
Abstract
Phosphorylation of residues in the C-terminal tail of the µ-opioid receptor (MOPr) is thought to be a key step in desensitization and internalization. Phosphorylation of C-terminal S/T residues is required for internalization (Just et al., 2013), but its role in desensitization is unknown. This study examined the influence of C-terminal phosphorylation sites on rapid desensitization of MOPr. Wild-type MOPr, a 3S/T-A mutant (S363A, T370A, S375A) that maintains internalization, 6S/T-A (S363A, T370A, S375A, T376A, T379A, T383A) and 11S/T-A (all C-terminal S/T residues mutated) mutants not internalized by MOPr agonists were stably expressed in AtT20 cells. Perforated patch-clamp recordings of MOPr-mediated activation of G-protein-activated inwardly rectifying potassium channel (Kir3.X) (GIRK) conductance by submaximal concentrations of Met(5)-enkephalin (ME) and somatostatin (SST; coupling to native SST receptor [SSTR]) were used to examine desensitization induced by exposure to ME and morphine for 5 minutes at 37°C. The rates of ME- and morphine-induced desensitization did not correlate with phosphorylation using phosphorylation site-specific antibodies. ME-induced MOPr desensitization and resensitization did not differ from wild-type for 3S/T-A and 6S/T-A but was abolished in 11S/T-A. Morphine-induced desensitization was unaffected in all three mutants, as was heterologous desensitization of SSTR. Morphine-induced desensitization (but not ME) was reduced by protein kinase C inhibition in wild-type MOPr and abolished in the 11S/T-A mutant, as was heterologous desensitization. These findings establish that MOPr desensitization can occur independently of S/T phosphorylation and internalization; however, C-terminal phosphorylation is necessary for some forms of desensitization because mutation of all C-terminal sites (11S/T-A) abolishes desensitization induced by ME.
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Affiliation(s)
- Arsalan Yousuf
- Discipline of Pharmacology, University of Sydney, New South Wales, Sydney, Australia (A.Y., S.Si., Y.-P.D., M.J.C.); and Institute of Pharmacology and Toxicology, Jena University Hospital, Friedrich Schiller University Jena, Jena, Germany (E.M., S.Sc.)
| | - Elke Miess
- Discipline of Pharmacology, University of Sydney, New South Wales, Sydney, Australia (A.Y., S.Si., Y.-P.D., M.J.C.); and Institute of Pharmacology and Toxicology, Jena University Hospital, Friedrich Schiller University Jena, Jena, Germany (E.M., S.Sc.)
| | - Setareh Sianati
- Discipline of Pharmacology, University of Sydney, New South Wales, Sydney, Australia (A.Y., S.Si., Y.-P.D., M.J.C.); and Institute of Pharmacology and Toxicology, Jena University Hospital, Friedrich Schiller University Jena, Jena, Germany (E.M., S.Sc.)
| | - Yan-Ping Du
- Discipline of Pharmacology, University of Sydney, New South Wales, Sydney, Australia (A.Y., S.Si., Y.-P.D., M.J.C.); and Institute of Pharmacology and Toxicology, Jena University Hospital, Friedrich Schiller University Jena, Jena, Germany (E.M., S.Sc.)
| | - Stefan Schulz
- Discipline of Pharmacology, University of Sydney, New South Wales, Sydney, Australia (A.Y., S.Si., Y.-P.D., M.J.C.); and Institute of Pharmacology and Toxicology, Jena University Hospital, Friedrich Schiller University Jena, Jena, Germany (E.M., S.Sc.)
| | - MacDonald J Christie
- Discipline of Pharmacology, University of Sydney, New South Wales, Sydney, Australia (A.Y., S.Si., Y.-P.D., M.J.C.); and Institute of Pharmacology and Toxicology, Jena University Hospital, Friedrich Schiller University Jena, Jena, Germany (E.M., S.Sc.)
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22
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Knapman A, Santiago M, Connor M. A6V polymorphism of the human μ-opioid receptor decreases signalling of morphine and endogenous opioids in vitro. Br J Pharmacol 2015; 172:2258-72. [PMID: 25521224 DOI: 10.1111/bph.13047] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/20/2014] [Revised: 11/11/2014] [Accepted: 12/09/2014] [Indexed: 11/28/2022] Open
Abstract
BACKGROUND AND PURPOSE Polymorphisms of the μ opioid receptor (MOPr) may contribute to the variation in responses to opioid drugs in clinical and unregulated situations. The A6V variant of MOPr (MOPr-A6V) is present in up to 20% of individuals in some populations, and may be associated with heightened susceptibility to drug abuse. There are no functional studies examining the acute signalling of MOPr-A6V in vitro, so we investigated potential functional differences between MOPr and MOPr-A6V at several signalling pathways using structurally distinct opioid ligands. EXPERIMENTAL APPROACH CHO and AtT-20 cells stably expressing MOPr and MOPr-A6V were used. AC inhibition and ERK1/2 phosphorylation were assayed in CHO cells; K channel activation was assayed in AtT-20 cells. KEY RESULTS Buprenorphine did not inhibit AC or stimulate ERK1/2 phosphorylation in CHO cells expressing MOPr-A6V, but buprenorphine activation of K channels in AtT-20 cells was preserved. [D-Ala2, N-MePhe4, Gly-ol]-enkephalin, morphine and β-endorphin inhibition of AC was significantly reduced via MOPr-A6V, as was signalling of all opioids to ERK1/2. However, there was little effect of the A6V variant on K channel activation. CONCLUSIONS AND IMPLICATIONS Signalling to AC and ERK via the mutant MOPr-A6V was decreased for many opioids, including the clinically significant drugs morphine, buprenorphine and fentanyl, as well endogenous opioids. The MOPr-A6V variant is common and this compromised signalling may affect individual responses to opioid therapy, while the possible disruption of the endogenous opioid system may contribute to susceptibility to substance abuse.
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Affiliation(s)
- Alisa Knapman
- Australian School of Advanced Medicine, Macquarie University, Sydney, NSW, Australia
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23
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Ma J, Yuan X, Qu H, Zhang J, Wang D, Sun X, Zheng Q. The role of reactive oxygen species in morphine addiction of SH-SY5Y cells. Life Sci 2015; 124:128-35. [PMID: 25623851 DOI: 10.1016/j.lfs.2015.01.003] [Citation(s) in RCA: 32] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/03/2014] [Revised: 01/13/2015] [Accepted: 01/14/2015] [Indexed: 02/04/2023]
Abstract
AIMS The alteration of ROS level is frequently observed in the course of morphine addiction, and ROS is proverbially involved in this process. This study aims to explore the relationship among morphine addiction, reactive oxygen species (ROS) and expression of μ-opioid receptor (MOR) in differentiated SH-SY5Y cells. MAIN METHODS SH-SY5Y cells were induced to differentiation by treatment with retinoic acid (RA); the activity of lactate dehydrogenase (LDH) and the nitro blue tetrazolium (NBT) reduction were assessed by spectrophotometry. Intracellular reactive oxygen species (ROS) was measured with the 2,7-dichlorofluorescin diacetate (DCFH-DA) assay. Cellular cAMP was determined by using a competitive protein binding kit. The mRNA expression of μ-opioid receptor (MOR) was evaluated by qRT-PCR. KEY FINDINGS Morphine-induced ROS are generated in a concentration- and time-dependent manner and inhibited by naloxone. Exogenous oxidants increase the level of ROS and aggravate morphine addiction, while the exogenous antioxidants efficiently reverse these effects. Morphine decreases the mRNA level of MOR in a concentration-dependent manner. And the mRNA level of MOR is remarkably reduced in the presence of exogenous oxidants and effectively promoted by antioxidants. SIGNIFICANCE This study indicates that ROS can affect morphine addiction through involving MOR. Treatment with ROS scavenging can serve as a medical therapy for morphine addiction.
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Affiliation(s)
- Jun Ma
- Binzhou Medical University, Yantai 264000, Shandong, China; Life Science School, Yantai University, Yantai 264000, Shandong, China
| | - Xuan Yuan
- Key Laboratory of Xinjiang Endemic Phytomedicine Resources, Ministry of Education, School of Pharmacy, Shihezi University, Shihezi 832002, Xinjiang, China
| | - Hengyi Qu
- Binzhou Medical University, Yantai 264000, Shandong, China
| | - Juan Zhang
- Key Laboratory of Xinjiang Endemic Phytomedicine Resources, Ministry of Education, School of Pharmacy, Shihezi University, Shihezi 832002, Xinjiang, China
| | - Dong Wang
- Qianfoshan Hospital of Shandong Province, Jinan 250014, China
| | - Xiling Sun
- Binzhou Medical University, Yantai 264000, Shandong, China.
| | - Qiusheng Zheng
- Binzhou Medical University, Yantai 264000, Shandong, China; Life Science School, Yantai University, Yantai 264000, Shandong, China.
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Arttamangkul S, Birdsong W, Williams JT. Does PKC activation increase the homologous desensitization of μ opioid receptors? Br J Pharmacol 2015; 172:583-92. [PMID: 24697621 PMCID: PMC4292970 DOI: 10.1111/bph.12712] [Citation(s) in RCA: 18] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/18/2013] [Revised: 03/19/2014] [Accepted: 03/23/2014] [Indexed: 12/22/2022] Open
Abstract
BACKGROUND AND PURPOSE This study examined the role of agents known to activate PKC on morphine-induced desensitization of μ-opioid receptors (MOP receptors) in brain slices containing locus coeruleus neurons. EXPERIMENTAL APPROACH Intracellular recordings were obtained from rat locus coeruleus neurons. Two measurements were used to characterize desensitization, the decline in hyperpolarization induced by application of a saturating concentration of agonist (acute desensitization) and the decrease in hyperpolarization induced by a subsaturating concentration of [Met](5) enkephalin (ME) following washout of the saturating concentration (sustained desensitization). Internalization of MOP receptors was studied in brain slices prepared from transgenic mice expressing Flag-MOP receptors. The subcellular distribution of activated PKC was examined using a novel fluorescent sensor of PKC in HEK293 cells. KEY RESULTS The phorbol esters (PMA and PDBu) and muscarine increased acute desensitization induced by a saturating concentration of morphine and ME. These effects were not sensitive to staurosporine. Staurosporine did not block the decline in hyperpolarization induced by muscarine. PDBu and muscarine did not affect sustained desensitization induced by ME nor did phorbol esters or muscarine change the trafficking of MOP receptors induced by morphine or ME. The distribution of activated PKC measured in HEK293 cells differed depending on which phorbol ester was applied. CONCLUSIONS AND IMPLICATIONS This study demonstrates a distinct difference in two measurements that are often used to evaluate desensitization. The measure of decline correlated well with the reduction in peak amplitudes caused by PKC activators implicating the modification of other factors rather than MOP receptors. 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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Allouche S, Noble F, Marie N. Opioid receptor desensitization: mechanisms and its link to tolerance. Front Pharmacol 2014; 5:280. [PMID: 25566076 PMCID: PMC4270172 DOI: 10.3389/fphar.2014.00280] [Citation(s) in RCA: 99] [Impact Index Per Article: 9.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/01/2014] [Accepted: 12/02/2014] [Indexed: 02/04/2023] Open
Abstract
Opioid receptors (OR) are part of the class A of G-protein coupled receptors and the target of the opiates, the most powerful analgesic molecules used in clinic. During a protracted use, a tolerance to analgesic effect develops resulting in a reduction of the effectiveness. So understanding mechanisms of tolerance is a great challenge and may help to find new strategies to tackle this side effect. This review will summarize receptor-related mechanisms that could underlie tolerance especially receptor desensitization. We will focus on the latest data obtained on molecular mechanisms involved in opioid receptor desensitization: phosphorylation, receptor uncoupling, internalization, and post-endocytic fate of the receptor.
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Affiliation(s)
- Stéphane Allouche
- Laboratoire de Signalisation, Électrophysiologie et Imagerie des Lésions D'ischémie-Reperfusion Myocardique, Université de Caen, UPRES EA 4650, IFR 146 ICORE Caen, France
| | - Florence Noble
- Centre National de la Recherche Scientifique, ERL 3649 Paris, France ; Institut National de la Santé et de la Recherche Médicale, UMR-S 1124 Paris, France ; Université Paris Descartes, Neuroplasticité et Thérapies des Addictions Paris, France
| | - Nicolas Marie
- Centre National de la Recherche Scientifique, ERL 3649 Paris, France ; Institut National de la Santé et de la Recherche Médicale, UMR-S 1124 Paris, France ; Université Paris Descartes, Neuroplasticité et Thérapies des Addictions Paris, France
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Glück L, Loktev A, Moulédous L, Mollereau C, Law PY, Schulz S. Loss of morphine reward and dependence in mice lacking G protein-coupled receptor kinase 5. Biol Psychiatry 2014; 76:767-74. [PMID: 24629717 PMCID: PMC4119866 DOI: 10.1016/j.biopsych.2014.01.021] [Citation(s) in RCA: 35] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 07/09/2013] [Revised: 01/28/2014] [Accepted: 01/28/2014] [Indexed: 12/13/2022]
Abstract
BACKGROUND The clinical benefits of opioid drugs are counteracted by the development of tolerance and addiction. We provide in vivo evidence for the involvement of G protein-coupled receptor kinases (GRKs) in opioid dependence in addition to their roles in agonist-selective mu-opioid receptor (MOR) phosphorylation. METHODS In vivo MOR phosphorylation was examined by immunoprecipitation and nanoflow liquid chromatography-tandem mass spectrometry analysis. Using the hot-plate and conditioned place preference test, we investigated opioid-related antinociception and reward effects in mice lacking GRK3 or GRK5. RESULTS Etonitazene and fentanyl stimulated the in vivo phosphorylation of multiple carboxyl-terminal phosphate acceptor sites, including threonine 370, serine 375, and threonine 379, which was predominantly mediated by GRK3. By contrast, morphine promoted a selective phosphorylation of serine 375 that was predominantly mediated by GRK5. In contrast to GRK3 knockout mice, GRK5 knockout mice exhibited reduced antinociceptive responses after morphine administration and developed morphine tolerance similar to wild-type mice but fewer signs of physical dependence. Also, morphine was ineffective in inducing conditioned place preference in GRK5 knockout mice, whereas cocaine conditioned place preference was retained. However, the reward properties of morphine were evident in knock-in mice expressing a phosphorylation-deficient S375A mutation of the MOR. CONCLUSIONS These findings show for the first time that MOR phosphorylation is regulated by agonist-selective recruitment of distinct GRK isoforms that influence different opioid-related behaviors. Modulation of GRK5 function could serve as a new approach for preventing addiction to opioids, while maintaining the analgesic properties of opioid drugs at an effective level.
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Affiliation(s)
- Laura Glück
- Institute of Pharmacology and Toxicology, Jena University Hospital, Friedrich Schiller University Jena, Drackendorfer Straße 1, D-07747 Jena, Germany
| | - Anastasia Loktev
- Institute of Pharmacology and Toxicology, Jena University Hospital, Friedrich Schiller University Jena, Drackendorfer Straße 1, D-07747 Jena, Germany
| | - Lionel Moulédous
- Institut de Pharmacologie et de Biologie Structurale, CNRS/Université de Toulouse, UMR 5089, 205 Route de Narbonne, 31077 Toulouse Cedex, France
| | - Catherine Mollereau
- Institut de Pharmacologie et de Biologie Structurale, CNRS/Université de Toulouse, UMR 5089, 205 Route de Narbonne, 31077 Toulouse Cedex, France
| | - Ping-Yee Law
- Department of Pharmacology, University of Minnesota Medical School, Minneapolis, Minnesota, 55455 USA
| | - Stefan Schulz
- Institute of Pharmacology and Toxicology, Jena University Hospital, Friedrich Schiller University Jena, Jena, Germany.
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Chidambaran V, Mavi J, Esslinger H, Pilipenko V, Martin LJ, Zhang K, Sadhasivam S. Association of OPRM1 A118G variant with risk of morphine-induced respiratory depression following spine fusion in adolescents. THE PHARMACOGENOMICS JOURNAL 2014; 15:255-62. [PMID: 25266679 DOI: 10.1038/tpj.2014.59] [Citation(s) in RCA: 28] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/26/2014] [Revised: 08/21/2014] [Accepted: 08/25/2014] [Indexed: 01/28/2023]
Abstract
The μ1 opioid receptor (OPRM1) genetic variant A118G results in decreased μ-receptor binding potential in the brain and increases morphine requirement. We hypothesized that OPRM1 A118G polymorphism will affect morphine-induced respiratory depression (MIRD) risk in children receiving morphine. A prospective genotype-blinded study was conducted in 88 healthy adolescents (11-18 years; 67% female, 85% Caucasian) who underwent spine fusion for scoliosis. They were followed for 48 h postoperatively for MIRD, pain scores, morphine consumption and use of analgesic adjuvants. Patients were genotyped for OPRM1 A118G variant-76% were wild type (AA) and 24% heterozygous/homozygous for variant (AG/GG). Multivariable logistic regression showed that the risk of MIRD in patients with AA genotype was significantly higher (odds ratio 5.6, 95% CI: 1.4-37.2, P=0.030). Presence of G allele was associated with higher pain scores (effect size 0.73, P=0.045). This novel association is an important step toward predicting MIRD susceptibility and personalizing morphine use.
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Affiliation(s)
- V Chidambaran
- 1] Department of Anesthesia, Cincinnati Children's Hospital Medical Center, Cincinnati, OH, USA [2] Department of Pediatrics, Cincinnati Children's Hospital Medical Center, Cincinnati, OH, USA
| | - J Mavi
- 1] Department of Anesthesia, Cincinnati Children's Hospital Medical Center, Cincinnati, OH, USA [2] Department of Pediatrics, Cincinnati Children's Hospital Medical Center, Cincinnati, OH, USA
| | - H Esslinger
- Department of Anesthesia, Cincinnati Children's Hospital Medical Center, Cincinnati, OH, USA
| | - V Pilipenko
- Division of Human Genetics, Cincinnati Children's Hospital Medical Center, Cincinnati, OH, USA
| | - L J Martin
- Division of Human Genetics, Cincinnati Children's Hospital Medical Center, Cincinnati, OH, USA
| | - K Zhang
- Division of Human Genetics, Cincinnati Children's Hospital Medical Center, Cincinnati, OH, USA
| | - S Sadhasivam
- 1] Department of Anesthesia, Cincinnati Children's Hospital Medical Center, Cincinnati, OH, USA [2] Department of Pediatrics, Cincinnati Children's Hospital Medical Center, Cincinnati, OH, USA
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Cawston EE, Redmond WJ, Breen CM, Grimsey NL, Connor M, Glass M. Real-time characterization of cannabinoid receptor 1 (CB1 ) allosteric modulators reveals novel mechanism of action. Br J Pharmacol 2014; 170:893-907. [PMID: 23937487 DOI: 10.1111/bph.12329] [Citation(s) in RCA: 94] [Impact Index Per Article: 9.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/03/2013] [Revised: 08/01/2013] [Accepted: 08/05/2013] [Indexed: 12/18/2022] Open
Abstract
BACKGROUND AND PURPOSE The cannabinoid receptor type 1 (CB1 ) has an allosteric binding site. The drugs ORG27569 {5-chloro-3-ethyl-N-[2-[4-(1-piperidinyl)phenyl]ethyl]-1H-indole-2-carboxamide} and PSNCBAM-1 {1-(4-chlorophenyl)-3-[3-(6-pyrrolidin-1-ylpyridin-2-yl)phenyl]urea} have been extensively characterized with regard to their effects on signalling of the orthosteric ligand CP55,940 {(-)-cis-3-[2-hydroxy-4-(1,1-dimethylheptyl)phenyl]-trans-4-(3-hydroxypropyl)cyclohexanol}, and studies have suggested that these allosteric modulators increase binding affinity but act as non-competitive antagonists in functional assays. To gain a deeper understanding of allosteric modulation of CB1 , we examined real-time signalling and trafficking responses of the receptor in the presence of allosteric modulators. EXPERIMENTAL APPROACH Studies of CB1 signalling were carried out in HEK 293 and AtT20 cells expressing haemagglutinin-tagged human and rat CB1 . We measured real-time accumulation of cAMP, activation and desensitization of potassium channel-mediated cellular hyperpolarization and CB1 internalization. KEY RESULTS ORG27569 and PSNCBAM-1 produce a complex, concentration and time-dependent modulation of agonist-mediated regulation of cAMP levels, as well as an increased rate of desensitization of CB1 -mediated cellular hyperpolarization and a decrease in agonist-induced receptor internalization. CONCLUSIONS AND IMPLICATIONS Contrary to previous studies characterizing allosteric modulators at CB1, this study suggests that the mechanism of action is not non-competitive antagonism of signalling, but rather that enhanced binding results in an increased rate of receptor desensitization and reduced internalization, which results in time-dependent modulation of cAMP signalling. The observed effect of the allosteric modulators is therefore dependent on the time frame over which the signalling response occurs. This finding may have important consequences for the potential therapeutic application of these compounds.
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Affiliation(s)
- Erin E Cawston
- Centre for Brain Research and Department of Pharmacology and Clinical Pharmacology, Faculty of Medical and Health Sciences, University of Auckland, Auckland, New Zealand
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Knapman A, Connor M. Cellular signalling of non-synonymous single-nucleotide polymorphisms of the human μ-opioid receptor (OPRM1). Br J Pharmacol 2014; 172:349-63. [PMID: 24527749 DOI: 10.1111/bph.12644] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/17/2013] [Revised: 01/21/2014] [Accepted: 02/07/2014] [Indexed: 12/15/2022] Open
Abstract
UNLABELLED There is significant variability in individual responses to opioid drugs, which is likely to have a significant genetic component. A number of non-synonymous single-nucleotide polymorphisms (SNPs) in the coding regions of the μ-opioid receptor gene (OPRM1) have been postulated to contribute to this variability. Although many studies have investigated the clinical influences of these μ-opioid receptor variants, the outcomes are reported in the context of thousands of other genes and environmental factors, and we are no closer to being able to predict individual response to opioids based on genotype. Investigation of how μ-opioid receptor SNPs affect their expression, coupling to second messengers, desensitization and regulation is necessary to understand how subtle changes in receptor structure can impact individual responses to opioids. To date, the few functional studies that have investigated the consequences of SNPs on the signalling profile of the μ-opioid receptor in vitro have shown that the common N40D variant has altered functional responses to some opioids, while other, rarer, variants display altered signalling or agonist-dependent regulation. Here, we review the data available on the effects of μ-opioid receptor polymorphisms on receptor function, expression and regulation in vitro, and discuss the limitations of the studies to date. Whether or not μ-opioid receptor SNPs contribute to individual variability in opioid responses remains an open question, in large part because we have relatively little good data about how the amino acid changes affect μ-opioid receptor function. 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)
- Alisa Knapman
- Australian School of Advanced Medicine, Macquarie University, Sydney, NSW, Australia
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Mann A, Illing S, Miess E, Schulz S. Different mechanisms of homologous and heterologous μ-opioid receptor phosphorylation. Br J Pharmacol 2014; 172:311-6. [PMID: 24517854 DOI: 10.1111/bph.12627] [Citation(s) in RCA: 34] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/01/2013] [Revised: 01/16/2014] [Accepted: 01/19/2014] [Indexed: 01/14/2023] Open
Abstract
UNLABELLED The efficiency of μ-opioid receptor signalling is tightly regulated and ultimately limited by the coordinated phosphorylation of intracellular serine and threonine residues. Here, we review and discuss recent progress in the generation and application of phosphosite-specific μ-opioid receptor antibodies, which have proved to be excellent tools for monitoring the spatial and temporal dynamics of receptor phosphorylation and dephosphorylation. Agonist-induced phosphorylation of μ-opioid receptors occurs at a conserved 10 residue sequence (370) TREHPSTANT(379) in the receptor's carboxyl-terminal cytoplasmic tail. Diverse opioids induce receptor phosphorylation at S375, present in the middle of this sequence, but only high-efficacy opioids have the ability to drive higher order phosphorylation on flanking residues (T370, T376 and T379). S375 is the initiating residue in a hierarchical phosphorylation cascade. In contrast, agonist-independent heterologous μ-opioid receptor phosphorylation occurs primarily at T370. The combination of phosphosite-specific antibodies and siRNA knockdown screening also facilitated the identification of relevant kinases and phosphatases. In fact, morphine induces a selective S375 phosphorylation that is predominantly catalysed by GPCR kinase 5 (GRK5), whereas multisite phosphorylation induced by high-efficacy opioids specifically requires GRK2/3. By contrast, T370 phosphorylation stimulated by phorbol esters or heterologous activation of Gq -coupled receptors is mediated by PKCα. Rapid μ-opioid receptor dephosphorylation occurs at or near the plasma membrane and is catalysed by protein phosphatase 1γ (PP1γ). These findings suggest that there are distinct phosphorylation motifs for homologous and heterologous regulation of μ-opioid receptor phosphorylation. However, it remains to be seen to what extent different μ-opioid receptor phosphorylation patterns contribute to the development of tolerance and dependence 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)
- Anika Mann
- Institute of Pharmacology and Toxicology, Jena University Hospital, Friedrich-Schiller-University, Jena, Germany
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31
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Macey TA, Bobeck EN, Suchland KL, Morgan MM, Ingram SL. Change in functional selectivity of morphine with the development of antinociceptive tolerance. Br J Pharmacol 2014; 172:549-61. [PMID: 24666417 DOI: 10.1111/bph.12703] [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: 10/18/2013] [Revised: 03/14/2014] [Accepted: 03/18/2014] [Indexed: 12/22/2022] Open
Abstract
BACKGROUND AND PURPOSE Opioids, such as morphine, are the most effective treatment for pain but their efficacy is diminished with the development of tolerance following repeated administration. Recently, we found that morphine activated ERK in opioid-tolerant but not in naïve rats, suggesting that morphine activation of μ-opioid receptors is altered following repeated morphine administration. Here, we have tested the hypothesis that μ-opioid receptor activation of ERK in the ventrolateral periaqueductal gray (vlPAG) is dependent on dynamin, a protein implicated in receptor endocytosis. EXPERIMENTAL APPROACH Rats were made tolerant to repeated microinjections of morphine into the vlPAG. The effects of dynamin on ERK activation and antinociception were assessed by microinjecting myristoylated dominant-negative dynamin peptide (Dyn-DN) or a scrambled control peptide into the vlPAG. Microinjection of a fluorescent dermorphin analogue (DERM-A594) into the vlPAG was used to monitor μ-opioid receptor internalization. KEY RESULTS Morphine did not activate ERK and Dyn-DN administration had no effect on morphine-induced antinociception in saline-pretreated rats. In contrast, morphine-induced ERK activation in morphine-pretreated rats that was blocked by Dyn-DN administration. Dyn-DN also inhibited morphine antinociception. Finally, morphine reduced DERM-A594 internalization only in morphine-tolerant rats indicating that μ-opioid receptors were internalized and unavailable to bind DERM-A594. CONCLUSIONS AND IMPLICATIONS Repeated morphine administration increased μ-opioid receptor activation of ERK signalling via a dynamin-dependent mechanism. These results demonstrate that the balance of agonist signalling to G-protein and dynamin-dependent pathways is altered, effectively changing the functional selectivity of the agonist-receptor complex. 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)
- T A Macey
- Department of Neurological Surgery, Oregon Health & Science University, Portland, OR, USA
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Brewer KL, Baran CA, Whitfield BR, Jensen AM, Clemens S. Dopamine D3 receptor dysfunction prevents anti-nociceptive effects of morphine in the spinal cord. Front Neural Circuits 2014; 8:62. [PMID: 24966815 PMCID: PMC4052813 DOI: 10.3389/fncir.2014.00062] [Citation(s) in RCA: 27] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/10/2014] [Accepted: 05/23/2014] [Indexed: 01/11/2023] Open
Abstract
Dopamine (DA) modulates spinal reflexes, including nociceptive reflexes, in part via the D3 receptor subtype. We have previously shown that mice lacking the functional D3 receptor (D3KO) exhibit decreased paw withdrawal latencies from painful thermal stimuli. Altering the DA system in the CNS, including D1 and D3 receptor systems, reduces the ability of opioids to provide analgesia. Here, we tested if the increased pain sensitivity in D3KO might result from a modified μ-opioid receptor (MOR) function at the spinal cord level. As D1 and D3 receptor subtypes have competing cellular effects and can form heterodimers, we tested if the changes in MOR function may be mediated in D3KO through the functionally intact D1 receptor system. We assessed thermal paw withdrawal latencies in D3KO and wild type (WT) mice before and after systemic treatment with morphine, determined MOR and phosphorylated MOR (p-MOR) protein expression levels in lumbar spinal cords, and tested the functional effects of DA and MOR receptor agonists in the isolated spinal cord. In vivo, a single morphine administration (2 mg/kg) increased withdrawal latencies in WT but not D3KO, and these differential effects were mimicked in vitro, where morphine modulated spinal reflex amplitudes (SRAs) in WT but not D3KO. Total MOR protein expression levels were similar between WT and D3KO, but the ratio of pMOR/total MOR was higher in D3KO. Blocking D3 receptors in the isolated WT cord precluded morphine's inhibitory effects observed under control conditions. Lastly, we observed an increase in D1 receptor protein expression in the lumbar spinal cord of D3KO. Our data suggest that the D3 receptor modulates the MOR system in the spinal cord, and that a dysfunction of the D3 receptor can induce a morphine-resistant state. We propose that the D3KO mouse may serve as a model to study the onset of morphine resistance at the spinal cord level, the primary processing site of the nociceptive pathway.
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Affiliation(s)
- Kori L Brewer
- Department of Physiology, Brody School of Medicine, East Carolina University Greenville, NC, USA
| | - Christine A Baran
- Department of Emergency Medicine, Brody School of Medicine, East Carolina University Greenville, NC, USA
| | - Brian R Whitfield
- Department of Emergency Medicine, Brody School of Medicine, East Carolina University Greenville, NC, USA
| | - A Marley Jensen
- Department of Physiology, Brody School of Medicine, East Carolina University Greenville, NC, USA
| | - Stefan Clemens
- Department of Physiology, Brody School of Medicine, East Carolina University Greenville, NC, USA
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Jaremko KM, Thompson NL, Reyes BAS, Jin J, Ebersole B, Jenney CB, Grigson PS, Levenson R, Berrettini WH, Van Bockstaele EJ. Morphine-induced trafficking of a mu-opioid receptor interacting protein in rat locus coeruleus neurons. Prog Neuropsychopharmacol Biol Psychiatry 2014; 50:53-65. [PMID: 24333843 PMCID: PMC3928604 DOI: 10.1016/j.pnpbp.2013.12.003] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 08/09/2013] [Revised: 11/26/2013] [Accepted: 12/05/2013] [Indexed: 12/14/2022]
Abstract
Opiate addiction is a devastating health problem, with approximately 2million people currently addicted to heroin or non-medical prescription opiates in the United States alone. In neurons, adaptations in cell signaling cascades develop following opioid actions at the mu opioid receptor (MOR). A novel putative target for intervention involves interacting proteins that may regulate trafficking of MOR. Morphine has been shown to induce a re-distribution of a MOR-interacting protein Wntless (WLS, a transport molecule necessary for secretion of neurotrophic Wnt proteins), from cytoplasmic to membrane compartments in rat striatal neurons. Given its opiate-sensitivity and its well-characterized molecular and cellular adaptations to morphine exposure, we investigated the anatomical distribution of WLS and MOR in the rat locus coeruleus (LC)-norepinephrine (NE) system. Dual immunofluorescence microscopy was used to test the hypothesis that WLS is localized to noradrenergic neurons of the LC and that WLS and MOR co-exist in common LC somatodendritic processes, providing an anatomical substrate for their putative interactions. We also hypothesized that morphine would influence WLS distribution in the LC. Rats received saline, morphine or the opiate agonist [d-Ala2, N-Me-Phe4, Gly-ol5]-enkephalin (DAMGO), and tissue sections through the LC were processed for immunogold-silver detection of WLS and MOR. Statistical analysis showed a significant re-distribution of WLS to the plasma membrane following morphine treatment in addition to an increase in the proximity of gold-silver labels for MOR and WLS. Following DAMGO treatment, MOR and WLS were predominantly localized within the cytoplasmic compartment when compared to morphine and control. In a separate cohort of rats, brains were obtained from saline-treated or heroin self-administering male rats for pulldown co-immunoprecipitation studies. Results showed an increased association of WLS and MOR following heroin exposure. As the LC-NE system is important for cognition as well as decisions underlying substance abuse, adaptations in WLS trafficking and expression may play a role in modulating MOR function in the LC and contribute to the negative sequelae of opiate exposure on executive function.
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Affiliation(s)
- Kellie M Jaremko
- Department of Pharmacology and Physiology, Drexel University College of Medicine, Philadelphia, PA 19102, United States
| | - Nicholas L Thompson
- Department of Pharmacology and Physiology, Drexel University College of Medicine, Philadelphia, PA 19102, United States
| | - Beverly A S Reyes
- Department of Pharmacology and Physiology, Drexel University College of Medicine, Philadelphia, PA 19102, United States.
| | - Jay Jin
- Department of Pharmacology, Penn State College of Medicine, Hershey, PA 17033, United States
| | - Brittany Ebersole
- Department of Pharmacology, Penn State College of Medicine, Hershey, PA 17033, United States
| | - Christopher B Jenney
- Department of Neural and Behavioral Sciences, Penn State College of Medicine, Hershey, PA 17033, United States
| | - Patricia S Grigson
- Department of Neural and Behavioral Sciences, Penn State College of Medicine, Hershey, PA 17033, United States
| | - Robert Levenson
- Department of Pharmacology, Penn State College of Medicine, Hershey, PA 17033, United States
| | - Wade H Berrettini
- Department of Psychiatry, Center for Neurobiology and Behavior, University of Pennsylvania School of Medicine, Philadelphia, PA 19104, United States
| | - Elisabeth J Van Bockstaele
- Department of Pharmacology and Physiology, Drexel University College of Medicine, Philadelphia, PA 19102, United States
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Prommer EE. Opioid rotation: logical choices for pain that is poorly responsive to morphine. PROGRESS IN PALLIATIVE CARE 2013. [DOI: 10.1179/096992609x392312] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/31/2022]
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Lee CWS, Ho IK. Pharmacological Profiles of Oligomerized μ-Opioid Receptors. Cells 2013; 2:689-714. [PMID: 24709876 PMCID: PMC3972655 DOI: 10.3390/cells2040689] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/21/2013] [Revised: 09/30/2013] [Accepted: 10/09/2013] [Indexed: 01/21/2023] Open
Abstract
Opioids are widely prescribed pain relievers with multiple side effects and potential complications. They produce analgesia via G-protein-protein coupled receptors: μ-, δ-, κ-opioid and opioid receptor-like 1 receptors. Bivalent ligands targeted to the oligomerized opioid receptors might be the key to developing analgesics without undesired side effects and obtaining effective treatment for opioid addicts. In this review we will update the biological effects of μ-opioids on homo- or hetero-oligomerized μ-opioid receptor and discuss potential mechanisms through which bivalent ligands exert beneficial effects, including adenylate cyclase regulation and receptor-mediated signaling pathways.
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Affiliation(s)
- Cynthia Wei-Sheng Lee
- Center for Drug Abuse and Addiction, China Medical University Hospital, Taichung 40447, Taiwan.
| | - Ing-Kang Ho
- Center for Drug Abuse and Addiction, China Medical University Hospital, Taichung 40447, Taiwan.
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36
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Knapman A, Abogadie F, McIntrye P, Connor M. A real-time, fluorescence-based assay for measuring μ-opioid receptor modulation of adenylyl cyclase activity in Chinese hamster ovary cells. ACTA ACUST UNITED AC 2013; 19:223-31. [PMID: 23989451 DOI: 10.1177/1087057113501391] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/17/2022]
Abstract
Inhibition of adenylyl cyclase (AC) activity is frequently used to measure µ-opioid receptor (MOR) activation. We sought to develop a simple, rapid assay of AC activity in whole cells that could be used to study MOR signaling. Chinese hamster ovary cells expressing human MOR (CHO-MOR cells) were grown in 96-well plates and loaded with membrane potential-sensitive fluorescent dye. CHO-MOR cells were treated with the AC activator forskolin (FSK), with or without simultaneous application of MOR agonists, and the resulting change in fluorescence was measured. CHO-MOR cells hyperpolarized in response to application of FSK (pEC₅₀, 7.3) or calcitonin (pEC₅₀, 9.4). A submaximally effective concentration of FSK (300 nM) caused a 52% ± 2% decrease in fluorescence. Simultaneous application of the opioids DAMGO (pEC₅₀, 7.4; E(max), 56%), morphine (pEC₅₀, 7.0; E(max), 61%); and buprenorphine (pEC₅₀, 8.6; E(max), 24%) inhibited the FSK response in a dose-dependent manner while having no effect by themselves. The effects of DAMGO were blocked by pertussis toxin. This assay represents a simple, robust method for real-time observation of AC inhibition by MOR in CHO cells. It represents an appealing alternative to end-point assays that rely on cAMP accumulation and can avoid potential confounds associated with rapid desensitization of MOR signaling.
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Affiliation(s)
- Alisa Knapman
- 1Australian School of Advanced Medicine, Macquarie University, NSW Australia
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Jamil MFA, Subki MFM, Lan TM, Majid MIA, Adenan MI. The effect of mitragynine on cAMP formation and mRNA expression of mu-opioid receptors mediated by chronic morphine treatment in SK-N-SH neuroblastoma cell. JOURNAL OF ETHNOPHARMACOLOGY 2013; 148:135-143. [PMID: 23608241 DOI: 10.1016/j.jep.2013.03.078] [Citation(s) in RCA: 34] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/17/2012] [Revised: 03/25/2013] [Accepted: 03/28/2013] [Indexed: 06/02/2023]
Abstract
ETHNOPHARMACOLOGICAL RELEVANCE [corrected] Mitragynine is an indole alkaloid compound of Mitragyna speciosa (M. speciosa) Korth. (Rubiaceae). This plant is native to the southern regions of Thailand and northern regions of Malaysia and is frequently used to manage the withdrawal symptoms in both countries. AIM OF STUDY To investigate the effect of mitragynine after chronic morphine treatment on cyclic AMP (cAMP) level and mRNA expression of mu-opioid receptor (MOR) in human neuroblastoma SK-N-SH cell. METHOD AND MATERIALS Mitragynine was isolated from the Mitragyna speciosa plant using the acid-base extraction method. The cAMP level upon forskolin stimulation in the cells was determined using the Calbiochem(®) Direct Immunoassay Kit. The mRNA expression of the MOR was carried out using quantitative RT-PCR. RESULT Cotreatment and pretreatment of morphine and mitragynine significantly reduced the production of cAMP level at a lower concentration of mitragynine while the higher concentration of this compound could lead to the development of tolerance and dependence as shown by the increase of the cAMP level production in foskolin stimulation. In MOR mRNA expression study, cotreatment of morphine with mitragynine significantly reduced the down-regulation of MOR mRNA expression as compared to morphine treatment only. CONCLUSION These finding suggest that mitragynine could possibly avoid the tolerance and dependence on chronic morphine treatment by reducing the up-regulation of cAMP level as well as reducing the down-regulation of MOR at a lower concentration of mitragynine.
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Affiliation(s)
- Mohd Fadzly Amar Jamil
- Malaysian Institute Pharmaceuticals and Nutraceuticals (IPharm), Ministry of Science, Technology and Innovation (MOSTI) Jalan Bukit Gambir, 11700 Gelugor Pulau Pinang, Malaysia
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Increased agonist affinity at the μ-opioid receptor induced by prolonged agonist exposure. J Neurosci 2013; 33:4118-27. [PMID: 23447620 DOI: 10.1523/jneurosci.4187-12.2013] [Citation(s) in RCA: 26] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/09/2023] Open
Abstract
Prolonged exposure to high-efficacy agonists results in desensitization of the μ-opioid receptor (MOR). Desensitized receptors are thought to be unable to couple to G-proteins, preventing downstream signaling; however, the changes to the receptor itself are not well characterized. In the current study, confocal imaging was used to determine whether desensitizing conditions cause a change in agonist-receptor interactions. Using rapid solution exchange, the binding kinetics of fluorescently labeled opioid agonist, dermorphin Alexa594 (derm A594), to MORs was measured in live cells. The affinity of derm A594 binding increased after prolonged treatment of cells with multiple agonists that are known to cause receptor desensitization. In contrast, binding of a fluorescent antagonist, naltrexamine Alexa594, was unaffected by similar agonist pretreatment. The increased affinity of derm A594 for the receptor was long-lived and partially reversed after a 45 min wash. Treatment of the cells with pertussis toxin did not alter the increase in affinity of the derm A594 for MOR. Likewise, the affinity of derm A594 for MORs expressed in mouse embryonic fibroblasts derived from arrestin 1 and 2 knock-out animals increased after treatment of the cells with the desensitization protocol. Thus, opioid receptors were "imprinted" with a memory of prior agonist exposure that was independent of G-protein activation or arrestin binding that altered subsequent agonist-receptor interactions. The increased affinity suggests that acute desensitization results in a long-lasting but reversible conformational change in the receptor.
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Co-activation of μ- and δ-opioid receptors elicits tolerance to morphine-induced ventilatory depression via generation of peroxynitrite. Respir Physiol Neurobiol 2013; 186:255-64. [PMID: 23473921 DOI: 10.1016/j.resp.2013.02.028] [Citation(s) in RCA: 22] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/23/2012] [Revised: 02/25/2013] [Accepted: 02/26/2013] [Indexed: 11/20/2022]
Abstract
We determined whether pretreatment with (1) the μ-/δ-opioid receptor (μ-/δ-OR) antagonist, naloxone, (2) the δ1,2-OR antagonist, naltrindole, or (3) the peroxynitrite scavenger, d-penicillamine, affects the development of tolerance to the ventilatory depressant effects of morphine in rats. The injection of morphine in vehicle-pretreated rats decreased minute ventilation predominantly via decreases in tidal volume. Pretreatment with naloxone blunted the responses to morphine whereas pretreatment with naltrindole or d-penicillamine did not. A second injection of morphine, given one day later, elicited markedly smaller responses in vehicle rats whereas it elicited pronounced ventilatory depression in rats that were pretreated with naloxone, naltrindole or d-penicillamine (prior to morphine) the day before. Moreover, the ventilatory responses elicited by subsequent exposure to a hypoxic-hypercapnic challenge were markedly depressed in naloxone- or d-penicillamine-pretreated rats compared to vehicle-pretreated rats. These findings suggest that activation of μ- and δ-ORs causes tolerance to the ventilatory depressant effects of morphine at least partly via the generation of peroxynitrite.
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Milne B, Jhamandas K, Sutak M, Grenier P, Cahill CM. Stereo-selective inhibition of spinal morphine tolerance and hyperalgesia by an ultra-low dose of the alpha-2-adrenoceptor antagonist efaroxan. Eur J Pharmacol 2013; 702:227-34. [DOI: 10.1016/j.ejphar.2013.01.022] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/25/2012] [Revised: 01/15/2013] [Accepted: 01/16/2013] [Indexed: 10/27/2022]
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Williams JT, Ingram SL, Henderson G, Chavkin C, von Zastrow M, Schulz S, Koch T, Evans CJ, Christie MJ. Regulation of μ-opioid receptors: desensitization, phosphorylation, internalization, and tolerance. Pharmacol Rev 2013; 65:223-54. [PMID: 23321159 DOI: 10.1124/pr.112.005942] [Citation(s) in RCA: 591] [Impact Index Per Article: 53.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022] Open
Abstract
Morphine and related µ-opioid receptor (MOR) agonists remain among the most effective drugs known for acute relief of severe pain. A major problem in treating painful conditions is that tolerance limits the long-term utility of opioid agonists. Considerable effort has been expended on developing an understanding of the molecular and cellular processes that underlie acute MOR signaling, short-term receptor regulation, and the progression of events that lead to tolerance for different MOR agonists. Although great progress has been made in the past decade, many points of contention and controversy cloud the realization of this progress. This review attempts to clarify some confusion by clearly defining terms, such as desensitization and tolerance, and addressing optimal pharmacological analyses for discerning relative importance of these cellular mechanisms. Cellular and molecular mechanisms regulating MOR function by phosphorylation relative to receptor desensitization and endocytosis are comprehensively reviewed, with an emphasis on agonist-biased regulation and areas where knowledge is lacking or controversial. The implications of these mechanisms for understanding the substantial contribution of MOR signaling to opioid tolerance are then considered in detail. While some functional MOR regulatory mechanisms contributing to tolerance are clearly understood, there are large gaps in understanding the molecular processes responsible for loss of MOR function after chronic exposure to opioids. Further elucidation of the cellular mechanisms that are regulated by opioids will be necessary for the successful development of MOR-based approaches to new pain therapeutics that limit the development of tolerance.
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Affiliation(s)
- John T Williams
- Vollum Institute, Oregon Health Sciences University, Portland, Oregon, USA
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Henderson F, May WJ, Gruber RB, Young AP, Palmer LA, Gaston B, Lewis SJ. Low-dose morphine elicits ventilatory excitant and depressant responses in conscious rats: Role of peripheral μ-opioid receptors. ACTA ACUST UNITED AC 2013; 3:111-124. [PMID: 24900948 DOI: 10.4236/ojmip.2013.33017] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
Abstract
The systemic administration of morphine affects ventilation via a mixture of central and peripheral actions. The aims of this study were to characterize the ventilatory responses elicited by a low dose of morphine in conscious rats; to determine whether tolerance develops to these responses; and to determine the potential roles of peripheral μ-opioid receptors (μ-ORs) in these responses. Ventilatory parameters were monitored via unrestrained whole-body plethysmography. Conscious male Sprague-Dawley rats received an intravenous injection of vehicle or the peripherally-restricted μ-OR antagonist, naloxone methiodide (NLXmi), and then three successive injections of morphine (1 mg/kg) given 30 min apart. The first injection of morphine in vehicle-treated rats elicited an array of ventilatory excitant (i.e., increases in frequency of breathing, minute volume, respiratory drive, peak inspiratory and expiratory flows, accompanied by decreases in inspiratory time and end inspiratory pause) and inhibitory (i.e., a decrease in tidal volume and an increase in expiratory time) responses. Subsequent injections of morphine elicited progressively and substantially smaller responses. The pattern of ventilatory responses elicited by the first injection of morphine was substantially affected by pretreatment with NLXmi whereas NLXmi minimally affected the development of tolerance to these responses. Low-dose morphine elicits an array of ventilatory excitant and depressant effects in conscious rats that are subject to the development of tolerance. Many of these initial actions of morphine appear to involve activation of peripheral μ-ORs whereas the development of tolerance to these responses does not.
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Affiliation(s)
- Fraser Henderson
- Pediatric Respiratory Medicine, University of Virginia School of Medicine, Charlottesville, VA 22908, USA
| | - Walter J May
- Pediatric Respiratory Medicine, University of Virginia School of Medicine, Charlottesville, VA 22908, USA
| | - Ryan B Gruber
- Division of Biology, Galleon Pharmaceuticals, Horsham, PA 19044, USA
| | - Alex P Young
- Pediatric Respiratory Medicine, University of Virginia School of Medicine, Charlottesville, VA 22908, USA
| | - Lisa A Palmer
- Pediatric Respiratory Medicine, University of Virginia School of Medicine, Charlottesville, VA 22908, USA
| | - Benjamin Gaston
- Pediatric Respiratory Medicine, University of Virginia School of Medicine, Charlottesville, VA 22908, USA
| | - Stephen J Lewis
- Pediatric Respiratory Medicine, University of Virginia School of Medicine, Charlottesville, VA 22908, USA
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Byrne LS, Peng J, Sarkar S, Chang SL. Interleukin-1 beta-induced up-regulation of opioid receptors in the untreated and morphine-desensitized U87 MG human astrocytoma cells. J Neuroinflammation 2012; 9:252. [PMID: 23164507 PMCID: PMC3526549 DOI: 10.1186/1742-2094-9-252] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/15/2012] [Accepted: 10/23/2012] [Indexed: 01/14/2023] Open
Abstract
Background Interleukin-1beta (IL-1β) is a pro-inflammatory cytokine that can be produced in the central nervous system during inflammatory conditions. We have previously shown that IL-1β expression is altered in the rat brain during a morphine tolerant state, indicating that this cytokine may serve as a convergent point between the immune challenge and opiate mediated biological pathways. We hypothesized that IL-1β up-regulates opioid receptors in human astrocytes in both untreated and morphine-desensitized states. Methods To test this hypothesis, we compared the basal expression of the mu (MOR), delta (DOR), and kappa (KOR) opioid receptors in the human U87 MG astrocytic cell line to SH-SY5Y neuronal and HL-60 immune cells using absolute quantitative real time RT-PCR (AQ-rt-RT-PCR). To demonstrate that IL-1β induced up-regulation of the MOR, DOR and KOR, U87 MG cells (2 x 105 cells/well) were treated with IL-1β (20 ng/mL or 40 ng/mL), followed by co-treatment with interleukin-1 receptor antagonist protein (IL-1RAP) (400 ng/mL or 400 ng/mL). The above experiment was repeated in the cells desensitized with morphine, where U87 MG cells were pre-treated with 100 nM morphine. The functionality of the MOR in U87 MG cells was then demonstrated using morphine inhibition of forksolin-induced intracellular cAMP, as determined by radioimmunoassay. Results U87 MG cells treated with IL-1β for 12 h showed a significant up-regulation of MOR and KOR. DOR expression was also elevated, although not significantly. Treatment with IL-1β also showed a significant up-regulation of the MOR in U87 MG cells desensitized with morphine. Co-treatment with IL-1β and interleukin-1 receptor antagonist protein (IL-1RAP) resulted in a significant decrease in IL-1β-mediated MOR up-regulation. Conclusion Our results indicate that the pro-inflammatory cytokine, IL-1β, affects opiate-dependent pathways by up-regulating the expression of the MOR in both untreated and morphine-desensitized U87 MG.
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Affiliation(s)
- Linda Staikos Byrne
- Institute of NeuroImmune Pharmacology, Seton Hall University, 400 South Orange Ave, South Orange, NJ 07079, USA
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A Continuous, Fluorescence-based Assay of µ-Opioid Receptor Activation in AtT-20 Cells. ACTA ACUST UNITED AC 2012; 18:269-76. [DOI: 10.1177/1087057112461376] [Citation(s) in RCA: 56] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/03/2023]
Abstract
Opioids are widely prescribed analgesics, but their use is limited due to development of tolerance and addiction, as well as high variability in individual response. The development of improved opioid analgesics requires high-throughput functional assays to assess large numbers of potential opioid ligands. In this study, we assessed the ability of a proprietary “no-wash” fluorescent membrane potential dye to act as a reporter of µ–opioid receptor (MOR) activation and desensitization via activation of G-protein-coupled inwardly rectifying potassium channels. AtT-20 cells stably expressing mouse MOR were assayed in 96-well plates using the Molecular Devices FLIPR membrane potential dye. Dye emission intensity decreased upon membrane hyperpolarization. Fluorescence decreased in a concentration-dependent manner upon application of a range of opioid ligands to the cells, with high-efficacy agonists producing a decrease of 35% to 40% in total fluorescence. The maximum effect of morphine faded in the continued presence of agonist, reflecting receptor desensitization. The effects of opioids were prevented by prior treatment with pertussis toxin and blocked by naloxone. We have demonstrated this assay to be an effective method for assessing ligand signaling at MOR, which may potentially be scaled up as an additional high-throughput screening technique for characterizing novel opioid ligands.
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Regan PM, Dave RS, Datta PK, Khalili K. Epigenetics of µ-opioid receptors: intersection with HIV-1 infection of the central nervous system. J Cell Physiol 2012; 227:2832-41. [PMID: 22034138 DOI: 10.1002/jcp.24004] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/01/2023]
Abstract
The abuse of intravenous drugs, such as heroin, has become a major public health concern due to the increased risk of HIV-1 infection. Opioids such as heroin were originally identified and subsequently abused for their analgesic effects. However, many investigations have found additional effects of opioids, including regulation of the immune system. As such, chronic opioid abuse has been shown to promote HIV-1 pathogenesis and facilitate HIV-1-associated neurocognitive dysfunction. Clinical opioids, such as morphine and methadone, as well as illicit opioids, such as heroin, exert their effects primarily through interactions with the µ-opioid receptor (MOR). However, the mechanisms by which opioids enhance neurocognitive dysfunction through MOR-mediated signaling pathways are not completely understood. New findings in the regulation of MOR expression, particularly epigenetic and transcriptional regulation as well as alternative splicing, sheds new insights into possible mechanisms of HIV-1 and opiate synergy. In this review, we identify mechanisms regulating MOR expression and propose novel mechanisms by which opioids and HIV-1 may modulate this regulation. Additionally, we suggest that differential regulation of newly identified MOR isoforms by opioids and HIV-1 has functional consequence in enhancing HIV-1 neurocognitive dysfunction.
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Affiliation(s)
- Patrick M Regan
- Department of Neuroscience, Center for Neurovirology, Temple University School of Medicine, Philadelphia, PA, USA
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Dang VC, Christie MJ. Mechanisms of rapid opioid receptor desensitization, resensitization and tolerance in brain neurons. Br J Pharmacol 2012; 165:1704-1716. [PMID: 21564086 DOI: 10.1111/j.1476-5381.2011.01482.x] [Citation(s) in RCA: 126] [Impact Index Per Article: 10.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022] Open
Abstract
Agonists acting on µ-opioid receptors (MOR) are very effective analgesics but cause tolerance during long-term or repeated exposure. Intensive efforts have been made to find novel opioid agonists that are efficacious analgesics but can elude the signalling events that cause tolerance. µ-Opioid agonists differentially couple to downstream signalling mechanisms. Some agonists, such as enkephalins, D-Ala(2),N-Me-Phe(4),Gly(5)-ol]-enkephalin (DAMGO), methadone and sufentanyl are efficacious at mediating G-protein and effector coupling, as well as triggering MOR regulatory events that include MOR phosphorylation, β-arrestin binding, receptor endocytosis and recycling. By contrast, morphine and closely related alkaloids can mediate efficacious MOR-effector coupling but poorly trigger receptor regulation. Several models have been proposed to relate differential MOR regulation by different opioids with their propensity to cause tolerance. Most are based on dogma that β-arrestin-2 (βarr-2) binding causes MOR desensitization and/or that MOR endocytosis and recycling are required for receptor resensitization. This review will examine some of these notions in light of recent evidence establishing that MOR dephosphorylation and resensitization do not require endocytosis. Recent evidence from opioid-treated animals also suggests that impaired MOR-effector coupling is driven, at least in part, by enhanced desensitization, as well as impaired resensitization that appears to be βarr-2 dependent. Better understanding of how chronic exposure to opioids alters receptor regulatory mechanisms may facilitate the development of effective analgesics that produce limited tolerance.
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Affiliation(s)
- Vu C Dang
- Department of Psychiatry, University of California, San Francisco, CA, USABrain & Mind Research Institute, University of Sydney, NSW, Australia
| | - MacDonald J Christie
- Department of Psychiatry, University of California, San Francisco, CA, USABrain & Mind Research Institute, University of Sydney, NSW, Australia
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Dang VC, Chieng BC, Christie MJ. Prolonged Stimulation of μ-Opioid Receptors Produces β-Arrestin-2-Mediated Heterologous Desensitization of α2-Adrenoceptor Function in Locus Ceruleus Neurons. Mol Pharmacol 2012; 82:473-80. [DOI: 10.1124/mol.112.079350] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/29/2023] Open
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Murali SS, Napier IA, Rycroft BK, Christie MJ. Opioid-related (ORL1) receptors are enriched in a subpopulation of sensory neurons and prolonged activation produces no functional loss of surface N-type calcium channels. J Physiol 2012; 590:1655-67. [PMID: 22371475 PMCID: PMC3413501 DOI: 10.1113/jphysiol.2012.228429] [Citation(s) in RCA: 28] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/17/2012] [Accepted: 02/20/2012] [Indexed: 01/20/2023] Open
Abstract
The opioid-related receptor, ORL1, is activated by the neuropeptide nociceptin/orphanin FQ (N/OFQ) and inhibits high-voltage-activated (HVA) calcium channel currents (I(Ca)) via a G-protein-coupled mechanism. Endocytosis of ORL1 receptor during prolonged N/OFQ exposure was proposed to cause N-type voltage-gated calcium channel (VGCC) internalization via physical interaction between ORL1 and the N-type channel. However, there is no direct electrophysiological evidence for this mechanism in dorsal root ganglion (DRG) neurons or their central nerve terminals. The present study tested this using whole-cell patch-clamp recordings of HVA I(Ca) in rat DRG neurons and primary afferent excitatory synaptic currents (eEPSCs) in spinal cord slices. DRG neurons were classified on the basis of diameter, isolectin-B4 (IB4) binding and responses to capsaicin, N/OFQ and a μ-opioid agonist, DAMGO. IB4-negative neurons less than 20 μm diameter were selectively responsive to N/OFQ as well as DAMGO. In these neurons, ORL1 desensitization by a supramaximal concentration of N/OFQ was not followed by a decrease in HVA I(Ca) current density or proportion of whole-cell HVA I(Ca) contributed by N-type VGCC as determined using the N-type channel selective blocker, ω-conotoxin CVID. There was also no decrease in the proportion of N-type I(Ca) when neurons were incubated at 37°C with N/OFQ for 30 min prior to recording. In spinal cord slices, N/OFQ consistently inhibited eEPSCs onto dorsal horn neurons. As observed in DRG neurons, preincubation of slices in N/OFQ for 30 min produced no decrease in the proportion of eEPSCs inhibited by CVID. In conclusion, no internalization of the N-type VGCC occurs in either the soma or central nerve terminals of DRG neurons following prolonged exposure to high, desensitizing concentrations of N/OFQ.
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Affiliation(s)
- Swetha S Murali
- Discipline of Pharmacology, University of Sydney, Sydney, Australia
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Barrett DM, Maguma HT, Taylor DA. Time course of altered sensitivity to inhibitory and excitatory agonist responses in the longitudinal muscle-myenteric plexus and analgesia in the Guinea pig after chronic morphine treatment. Front Pharmacol 2012; 2:88. [PMID: 22291645 PMCID: PMC3254177 DOI: 10.3389/fphar.2011.00088] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/12/2011] [Accepted: 12/18/2011] [Indexed: 11/25/2022] Open
Abstract
Tolerance that develops after chronic morphine exposure has been proposed to be an adaptive response that develops and decays over a defined time course. The present study examined the development of tolerance to the acute hypothermic and analgesic effects of morphine and correlated the time course for the desensitization in vivo with the reduced responsiveness to DAMGO and 2-CADO and increased responsiveness to nicotine of the longitudinal muscle/myenteric plexus (LM/MP) preparation in vitro. Assessment was performed at various times after morphine or placebo pellet implantation. Morphine produced a modest hypothermic response to which no tolerance developed. However, the development of tolerance to the analgesic effect of morphine, the inhibitory effect of DAMGO and CADO on neurogenic twitches of the LM/MP and hypersensitivity to the contractile response to nicotine was observed to occur in a time-dependent manner. The alterations in sensitivity to DAMGO, nicotine, and responsiveness to morphine analgesia occurred between days 4 and 10 and returned to normal by day 14 post-implantation. In contrast, sensitivity of LM/MP preparations to 2-CADO displayed a similar time-dependent onset but the tolerance persisted beyond 14 days after implantation. These data suggest that the heterologous tolerance that develops after chronic morphine treatment is time-dependent and persistent but, ultimately returns to normal in the absence of any intervention. Furthermore, the data suggest that the basis of the adaptive phenomenon may involve multiple cellular mechanisms including the modulation of cell excitability and normal physiology but the consequences of the adaptation extend to all effects of the agonist.
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Affiliation(s)
- Dane M Barrett
- The Department of Pharmacology and Toxicology, The Brody School of Medicine at East Carolina University Greenville, NC, USA
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Mercadante S, Porzio G, Ferrera P, Fulfaro F, Aielli F, Verna L, Villari P, Ficorella C, Gebbia V, Riina S, Casuccio A, Mangione S. Sustained-release oral morphine versus transdermal fentanyl and oral methadone in cancer pain management. Eur J Pain 2012; 12:1040-6. [DOI: 10.1016/j.ejpain.2008.01.013] [Citation(s) in RCA: 96] [Impact Index Per Article: 8.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/22/2007] [Revised: 01/28/2008] [Accepted: 01/28/2008] [Indexed: 10/22/2022]
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