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Chrószcz M, Hajto J, Misiołek K, Szumiec Ł, Ziemiańska M, Radlicka-Borysewska A, Borczyk M, Zięba M, Gołda S, Siwiec M, Ziółkowska B, Piechota M, Korostyński M, Rodriguez Parkitna J. μ-Opioid receptor transcriptional variants in the murine forebrain and spinal cord. Gene 2025; 932:148890. [PMID: 39187136 DOI: 10.1016/j.gene.2024.148890] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/28/2024] [Revised: 08/14/2024] [Accepted: 08/22/2024] [Indexed: 08/28/2024]
Abstract
Oprm1, the gene encoding the μ-opioid receptor, has multiple reported transcripts, with a variable 3' region and many alternative sequences encoding the C-terminus of the protein. The functional implications of this variability remain mostly unexplored, though a recurring notion is that it could be exploited by developing selective ligands with improved clinical profiles. Here, we comprehensively examined Oprm1 transcriptional variants in the murine central nervous system, using long-read RNAseq as well as spatial and single-cell transcriptomics. The results were validated with RNAscope in situ hybridization. We found a mismatch between transcripts annotated in the mouse genome (GRCm38/mm10) and the RNA-seq results. Sequencing data indicated that the primary Oprm1 transcript has a 3' terminus located on chr10:6,860,027, which is ∼ 9.5 kilobases downstream of the longest annotated exon 4 end. Long-read sequencing confirmed that the final Oprm1 exon included a 10.2 kilobase long 3' untranslated region, and the presence of the long variant was unambiguously confirmed using RNAscope in situ hybridization in the thalamus, striatum, cortex and spinal cord. Conversely, expression of the Oprm1 reference transcript or alternative transcripts of the Oprm1 gene was absent or close to the detection limit. Thus, the primary transcript of the Oprm1 mouse gene is a variant with a long 3' untranslated region, which is homologous to the human OPRM1 primary transcript and encodes the same conserved C-terminal amino acid sequence.
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Affiliation(s)
- Magdalena Chrószcz
- Department of Molecular Neuropharmacology, Maj Institute of Pharmacology Polish Academy of Sciences, Krakow, Poland
| | - Jacek Hajto
- Laboratory of Pharmacogenomics, Maj Institute of Pharmacology Polish Academy of Sciences, Krakow, Poland
| | - Klaudia Misiołek
- Department of Molecular Neuropharmacology, Maj Institute of Pharmacology Polish Academy of Sciences, Krakow, Poland
| | - Łukasz Szumiec
- Department of Molecular Neuropharmacology, Maj Institute of Pharmacology Polish Academy of Sciences, Krakow, Poland
| | - Magdalena Ziemiańska
- Department of Molecular Neuropharmacology, Maj Institute of Pharmacology Polish Academy of Sciences, Krakow, Poland
| | - Anna Radlicka-Borysewska
- Department of Molecular Neuropharmacology, Maj Institute of Pharmacology Polish Academy of Sciences, Krakow, Poland
| | - Małgorzata Borczyk
- Laboratory of Pharmacogenomics, Maj Institute of Pharmacology Polish Academy of Sciences, Krakow, Poland
| | - Mateusz Zięba
- Laboratory of Pharmacogenomics, Maj Institute of Pharmacology Polish Academy of Sciences, Krakow, Poland
| | - Sławomir Gołda
- Department of Molecular Neuropharmacology, Maj Institute of Pharmacology Polish Academy of Sciences, Krakow, Poland
| | - Marcin Siwiec
- Department of Physiology, Maj Institute of Pharmacology Polish Academy of Sciences, Krakow, Poland
| | - Barbara Ziółkowska
- Department of Molecular Neuropharmacology, Maj Institute of Pharmacology Polish Academy of Sciences, Krakow, Poland
| | - Marcin Piechota
- Laboratory of Pharmacogenomics, Maj Institute of Pharmacology Polish Academy of Sciences, Krakow, Poland
| | - Michał Korostyński
- Laboratory of Pharmacogenomics, Maj Institute of Pharmacology Polish Academy of Sciences, Krakow, Poland
| | - Jan Rodriguez Parkitna
- Department of Molecular Neuropharmacology, Maj Institute of Pharmacology Polish Academy of Sciences, Krakow, Poland.
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2
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Havel V, Kruegel AC, Bechand B, McIntosh S, Stallings L, Hodges A, Wulf MG, Nelson M, Hunkele A, Ansonoff M, Pintar JE, Hwu C, Ople RS, Abi-Gerges N, Zaidi SA, Katritch V, Yang M, Javitch JA, Majumdar S, Hemby SE, Sames D. Oxa-Iboga alkaloids lack cardiac risk and disrupt opioid use in animal models. Nat Commun 2024; 15:8118. [PMID: 39304653 DOI: 10.1038/s41467-024-51856-y] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/07/2023] [Accepted: 08/16/2024] [Indexed: 09/22/2024] Open
Abstract
Ibogaine and its main metabolite noribogaine provide important molecular prototypes for markedly different treatment of substance use disorders and co-morbid mental health illnesses. However, these compounds present a cardiac safety risk and a highly complex molecular mechanism. We introduce a class of iboga alkaloids - termed oxa-iboga - defined as benzofuran-containing iboga analogs and created via structural editing of the iboga skeleton. The oxa-iboga compounds lack the proarrhythmic adverse effects of ibogaine and noribogaine in primary human cardiomyocytes and show superior efficacy in animal models of opioid use disorder in male rats. They act as potent kappa opioid receptor agonists in vitro and in vivo, but exhibit atypical behavioral features compared to standard kappa opioid agonists. Oxa-noribogaine induces long-lasting suppression of morphine, heroin, and fentanyl intake after a single dose or a short treatment regimen, reversal of persistent opioid-induced hyperalgesia, and suppression of opioid drug seeking in rodent relapse models. As such, oxa-iboga compounds represent mechanistically distinct iboga analogs with therapeutic potential.
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MESH Headings
- Animals
- Humans
- Male
- Ibogaine/analogs & derivatives
- Ibogaine/pharmacology
- Ibogaine/therapeutic use
- Rats
- Myocytes, Cardiac/drug effects
- Myocytes, Cardiac/metabolism
- Opioid-Related Disorders/drug therapy
- Analgesics, Opioid/adverse effects
- Analgesics, Opioid/pharmacology
- Rats, Sprague-Dawley
- Disease Models, Animal
- Receptors, Opioid, kappa/metabolism
- Receptors, Opioid, kappa/agonists
- Receptors, Opioid, kappa/genetics
- Alkaloids/pharmacology
- Hyperalgesia/chemically induced
- Hyperalgesia/drug therapy
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Affiliation(s)
- Václav Havel
- Department of Chemistry, Columbia University, New York, NY, 10027, USA
| | - Andrew C Kruegel
- Department of Chemistry, Columbia University, New York, NY, 10027, USA
| | - Benjamin Bechand
- Department of Chemistry, Columbia University, New York, NY, 10027, USA
| | - Scot McIntosh
- Department of Basic Pharmaceutical Sciences, Fred Wilson School of Pharmacy, High Point University, High Point, NC, 27268, USA
| | - Leia Stallings
- Department of Basic Pharmaceutical Sciences, Fred Wilson School of Pharmacy, High Point University, High Point, NC, 27268, USA
| | - Alana Hodges
- Department of Basic Pharmaceutical Sciences, Fred Wilson School of Pharmacy, High Point University, High Point, NC, 27268, USA
| | - Madalee G Wulf
- Department of Chemistry, Columbia University, New York, NY, 10027, USA
| | - Mel Nelson
- Department of Molecular Pharmacology and Therapeutics, Columbia University, New York, NY, 10032, USA
- Department of Psychiatry, Columbia University, New York, NY, 10032, USA
- Division of Molecular Therapeutics, New York State Psychiatric Institute, New York, NY, 10032, USA
| | - Amanda Hunkele
- Department of Neurology and Molecular Pharmacology, Memorial Sloan Kettering Cancer Center, New York, NY, 10065, USA
- Center for Clinical Pharmacology, University of Health Sciences & Pharmacy at St Louis and Washington University School of Medicine, St Louis, MO, 63110, USA
| | - Michael Ansonoff
- Department of Neuroscience and Cell Biology, Rutgers University, Piscataway, NJ, 08854, USA
| | - John E Pintar
- Department of Neuroscience and Cell Biology, Rutgers University, Piscataway, NJ, 08854, USA
- Rutgers Addiction Research Center, Brain Health Institute, Rutgers University, Piscataway, NJ, 08854, USA
| | - Christopher Hwu
- Department of Chemistry, Columbia University, New York, NY, 10027, USA
| | - Rohini S Ople
- Center for Clinical Pharmacology, University of Health Sciences & Pharmacy at St Louis and Washington University School of Medicine, St Louis, MO, 63110, USA
- Washington University Pain Center and Department of Anesthesiology, Washington University School of Medicine, St Louis, MO, 63110, USA
| | - Najah Abi-Gerges
- AnaBios Corporation, 1155 Island Ave, Suite 200, San Diego, CA, 92101, USA
| | - Saheem A Zaidi
- Department of Quantitative and Computational Biology, University of Southern California, Los Angeles, CA, 90089, USA
- Department of Chemistry, Bridge Institute, Michelson Center for Convergent Sciences, University of Southern California, Los Angeles, CA, 90089, USA
| | - Vsevolod Katritch
- Department of Quantitative and Computational Biology, University of Southern California, Los Angeles, CA, 90089, USA
- Department of Chemistry, Bridge Institute, Michelson Center for Convergent Sciences, University of Southern California, Los Angeles, CA, 90089, USA
| | - Mu Yang
- Mouse Neurobehavioral Core facility, Columbia University Irving Medical Center, New York, NY, 10032, USA
| | - Jonathan A Javitch
- Department of Molecular Pharmacology and Therapeutics, Columbia University, New York, NY, 10032, USA
- Department of Psychiatry, Columbia University, New York, NY, 10032, USA
- Division of Molecular Therapeutics, New York State Psychiatric Institute, New York, NY, 10032, USA
| | - Susruta Majumdar
- Department of Neurology and Molecular Pharmacology, Memorial Sloan Kettering Cancer Center, New York, NY, 10065, USA
- Center for Clinical Pharmacology, University of Health Sciences & Pharmacy at St Louis and Washington University School of Medicine, St Louis, MO, 63110, USA
- Washington University Pain Center and Department of Anesthesiology, Washington University School of Medicine, St Louis, MO, 63110, USA
| | - Scott E Hemby
- Department of Basic Pharmaceutical Sciences, Fred Wilson School of Pharmacy, High Point University, High Point, NC, 27268, USA
| | - Dalibor Sames
- Department of Chemistry, Columbia University, New York, NY, 10027, USA.
- The Zuckerman Mind Brain Behavior Institute at Columbia University, New York, NY, USA.
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3
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Huang YH, Lin SY, Ou LC, Huang WC, Chao PK, Chang YC, Chang HF, Lee PT, Yeh TK, Kuo YH, Tien YW, Xi JH, Tao PL, Chen PY, Chuang JY, Shih C, Chen CT, Tung CW, Loh HH, Ueng SH, Yeh SH. Discovery of a mu-opioid receptor modulator that in combination with morphinan antagonists induces analgesia. Cell Chem Biol 2024:S2451-9456(24)00272-1. [PMID: 39025070 DOI: 10.1016/j.chembiol.2024.06.013] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/02/2023] [Revised: 04/09/2024] [Accepted: 06/22/2024] [Indexed: 07/20/2024]
Abstract
Morphinan antagonists, which block opioid effects at mu-opioid receptors, have been studied for their analgesic potential. Previous studies have suggested that these antagonists elicit analgesia with fewer adverse effects in the presence of the mutant mu-opioid receptor (MOR; S196A). However, introducing a mutant receptor for medical applications represents significant challenges. We hypothesize that binding a chemical compound to the MOR may elicit a comparable effect to the S196A mutation. Through high-throughput screening and structure-activity relationship studies, we identified a modulator, 4-(2-(4-fluorophenyl)-4-oxothiazolidin-3-yl)-3-methylbenzoic acid (BPRMU191), which confers agonistic properties to small-molecule morphinan antagonists, which induce G protein-dependent MOR activation. Co-application of BPRMU191 and morphinan antagonists resulted in MOR-dependent analgesia with diminished side effects, including gastrointestinal dysfunction, antinociceptive tolerance, and physical and psychological dependence. Combining BPRMU191 and morphinan antagonists could serve as a potential therapeutic strategy for severe pain with reduced adverse effects and provide an avenue for studying G protein-coupled receptor modulation.
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Affiliation(s)
- Yi-Han Huang
- Institute of Biotechnology and Pharmaceutical Research, National Health Research Institutes, Miaoli 35053, Taiwan; Research Center for Neuroscience, Taipei Medical University, Taipei 110, Taiwan
| | - Shu-Yu Lin
- Institute of Biotechnology and Pharmaceutical Research, National Health Research Institutes, Miaoli 35053, Taiwan
| | - Li-Chin Ou
- Institute of Biotechnology and Pharmaceutical Research, National Health Research Institutes, Miaoli 35053, Taiwan
| | - Wei-Cheng Huang
- Institute of Biotechnology and Pharmaceutical Research, National Health Research Institutes, Miaoli 35053, Taiwan
| | - Po-Kuan Chao
- Institute of Biotechnology and Pharmaceutical Research, National Health Research Institutes, Miaoli 35053, Taiwan
| | - Yung-Chiao Chang
- Institute of Biotechnology and Pharmaceutical Research, National Health Research Institutes, Miaoli 35053, Taiwan
| | - Hsiao-Fu Chang
- Institute of Biotechnology and Pharmaceutical Research, National Health Research Institutes, Miaoli 35053, Taiwan
| | - Pin-Tse Lee
- Institute of Biotechnology and Pharmaceutical Research, National Health Research Institutes, Miaoli 35053, Taiwan
| | - Teng-Kuang Yeh
- Institute of Biotechnology and Pharmaceutical Research, National Health Research Institutes, Miaoli 35053, Taiwan
| | - Yu-Hsien Kuo
- Institute of Biotechnology and Pharmaceutical Research, National Health Research Institutes, Miaoli 35053, Taiwan
| | - Ya-Wen Tien
- Institute of Biotechnology and Pharmaceutical Research, National Health Research Institutes, Miaoli 35053, Taiwan
| | - Jing-Hua Xi
- Department of Pharmacology, Medical School University of Minnesota, Minneapolis, MN 55455-0217, USA
| | - Pao-Luh Tao
- Center for Neuropsychiatric Research, National Health Research Institutes, Miaoli 35053, Taiwan
| | - Pin-Yuan Chen
- Department of Neurosurgery, Keelung Chang Gung Memorial Hospital, Chang Gung University, Keelung 20401, Taiwan
| | - Jian-Ying Chuang
- Research Center for Neuroscience, Taipei Medical University, Taipei 110, Taiwan; Ph.D. Program in Medical Neuroscience, College of Medical Science and Technology, Taipei Medical University and National Health Research Institutes, Taipei 110, Taiwan
| | - Chuan Shih
- Institute of Biotechnology and Pharmaceutical Research, National Health Research Institutes, Miaoli 35053, Taiwan
| | - Chiung-Tong Chen
- Institute of Biotechnology and Pharmaceutical Research, National Health Research Institutes, Miaoli 35053, Taiwan
| | - Chun-Wei Tung
- Institute of Biotechnology and Pharmaceutical Research, National Health Research Institutes, Miaoli 35053, Taiwan
| | - Horace H Loh
- Department of Pharmacology, Medical School University of Minnesota, Minneapolis, MN 55455-0217, USA; Bioland Laboratory (Guangzhou Regenerative Medicine and Health Guangdong Laboratory), Guangzhou 510005, China.
| | - Shau-Hua Ueng
- Institute of Biotechnology and Pharmaceutical Research, National Health Research Institutes, Miaoli 35053, Taiwan; School of Pharmacy, College of Medicine, National Cheng Kung University, Tainan 70101, Taiwan.
| | - Shiu-Hwa Yeh
- Institute of Biotechnology and Pharmaceutical Research, National Health Research Institutes, Miaoli 35053, Taiwan; Ph.D. Program in Medical Neuroscience, College of Medical Science and Technology, Taipei Medical University and National Health Research Institutes, Taipei 110, Taiwan.
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4
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Huang P, Ho CK, Cao D, Inan S, Rawls SM, Li M, Huang B, Pagare PP, Townsend EA, Poklis JL, Halquist MS, Banks M, Zhang Y, Liu-Chen LY. NCP, a dual kappa and mu opioid receptor agonist, is a potent analgesic against inflammatory pain without reinforcing or aversive properties. J Pharmacol Exp Ther 2024; 389:JPET-AR-2023-001870. [PMID: 38409113 PMCID: PMC10949162 DOI: 10.1124/jpet.123.001870] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/09/2023] [Revised: 01/24/2024] [Accepted: 01/30/2024] [Indexed: 02/28/2024] Open
Abstract
While agonists of mu (MOR) and kappa (KOR) opioid receptors have analgesic effects, they produce euphoria and dysphoria, respectively. Other side effects include respiratory depression and addiction for MOR agonists and sedation for KOR agonists. We reported that 17-cyclopropylmethyl-3,14β-dihydroxy-4,5α-epoxy-6β-{[4'-(2'-cyanopyridyl)]carboxamido}cmorphinan (NCP) displayed potent KOR full agonist and MOR partial agonist activities (58%) with 6.5x KOR-over-MOR selectivity in vitro Herein, we characterized pharmacological effects of NCP in rodents. In mice, NCP exerted analgesic effects against inflammatory pain in both the formalin test and the acetic acid writhing test, with A50 values of 47.6 and 14.4 microg/kg (s.c.), respectively. The analgesic effects in the acetic acid writhing test were mediated by the KOR. NCP at doses much higher than those effective in reducing inflammatory pain did not produce antinociception in the hot plate and tail flick tests, inhibit compound 48/80-induced scratching, cause conditioned place aversion (CPA) or preference, impair rotarod performance, inhibit locomotor activity, cause respiratory depression, or precipitate morphine withdrawal. However, NCP (10~100 microg/kg) inhibited gastrointestinal transit with a maximum of ~40% inhibition. In MOR knockout mice, NCP caused CPA, demonstrating that its lack of CPA is due to combined actions on the MOR and KOR. Following s.c. injection, NCP penetrated into the mouse brain. In rats trained to self-administer heroin, NCP (1~320 microg/kg/infusion) did not function as a reinforcer. Thus, NCP produces potent analgesic effects via KOR without side effects except constipation. Therefore, dual full KOR/partial MOR agonists with moderate KOR-over-MOR selectivity may be promising as non-addictive analgesics for inflammatory pain. Significance Statement Developing non-addictive analgesics is crucial for reducing opioid overdose deaths, minimizing drug misuse, and promoting safer pain management practices. Herein, pharmacology of a potential non-addictive analgesic, NCP, is reported. NCP has full KOR agonist / partial MOR agonist activities with a 6.5 x selectivity for KOR over MOR. Unlike MOR agonists, analgesic doses of NCP do not lead to self-administration or respiratory depression. Furthermore, NCP does not produce aversion, hypolocomotion, or motor incoordination, side effects typically associated with KOR activation.
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Affiliation(s)
- Peng Huang
- Temple University Lewis Katz School of Medicine, United States
| | - Conrad K Ho
- Temple University Lewis Katz School of Medicine, United States
| | - Danni Cao
- Temple University Lewis Katz School of Medicine, United States
| | - Saadet Inan
- Center for Substance Abuse Research, Lewis Katz School of Medicine, Temple University, Lewis Katz School of Medicine, Temple University, United States
| | - Scott M Rawls
- Temple University Lewis Katz School of Medicine, United States
| | - Mengchu Li
- Virginia Commonwealth University School of Pharmacy, United States
| | - Boshi Huang
- Virginia Commonwealth University School of Pharmacy, United States
| | - Piyusha P Pagare
- Virginia Commonwealth University School of Pharmacy, United States
| | | | | | | | - Matthew Banks
- Virginia Commonwealth University School of Medicine, United States
| | - Yan Zhang
- Virginia Commonwealth University School of Pharmacy, United States
| | - Lee-Yuan Liu-Chen
- Center for Substance Abuse Research, Temple University Lewis Katz School of Medicine, United States
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5
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Hsu YT, Chen SR, Chang YC, Chang HF, Yeh TK, Chuang JY, Loh HH, Hsieh HP, Ueng SH, Yeh SH. A dual nociceptin and mu opioid receptor agonist exhibited robust antinociceptive effect with decreased side effects. Eur J Med Chem 2023; 258:115608. [PMID: 37437352 DOI: 10.1016/j.ejmech.2023.115608] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/15/2023] [Revised: 06/13/2023] [Accepted: 06/26/2023] [Indexed: 07/14/2023]
Abstract
The compelling demand of a consummate analgesic medication without addiction is rising due to the clinical mistreatment. Additionally, the series of severe untoward effects usually deterred the utilization while coping with serious pain. As a possible turning point, we revealed that compound 14 is a dual agonist of mu opioid receptor (MOR) and nociceptin-orphanin FQ opioid peptide (NOP) receptor in this study. More importantly, compound 14 achieves pain relieving at very small doses, meanwhile, reduces several unwanted side effects such as constipation, reward, tolerance and withdrawal effects. Here, we evaluated the antinociception and side effects of this novel compound from wild type and humanized mice to further develop a safer prescription analgesic drug.
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Affiliation(s)
- Ying-Ting Hsu
- Institute of Biotechnology and Pharmaceutical Research, National Health Research Institutes, Miaoli County, 35053, Taiwan, ROC; The Ph.D. Program in Medical Neuroscience, College of Medical Science and Technology, Taipei Medical University and National Health Research Institutes, Taipei, 110, Taiwan, ROC
| | - Shen-Ren Chen
- Institute of Biotechnology and Pharmaceutical Research, National Health Research Institutes, Miaoli County, 35053, Taiwan, ROC
| | - Yung-Chiao Chang
- Institute of Biotechnology and Pharmaceutical Research, National Health Research Institutes, Miaoli County, 35053, Taiwan, ROC
| | - Hsiao-Fu Chang
- Institute of Biotechnology and Pharmaceutical Research, National Health Research Institutes, Miaoli County, 35053, Taiwan, ROC
| | - Teng-Kuang Yeh
- Institute of Biotechnology and Pharmaceutical Research, National Health Research Institutes, Miaoli County, 35053, Taiwan, ROC
| | - Jian-Ying Chuang
- The Ph.D. Program in Medical Neuroscience, College of Medical Science and Technology, Taipei Medical University and National Health Research Institutes, Taipei, 110, Taiwan, ROC
| | - Horace H Loh
- Bioland Laboratory (Guangzhou Regenerative Medicine and Health Guangdong Laboratory), Guangzhou, 10005, China; Department of Pharmacology, Medical School University of Minnesota, Minneapolis, MN, 55455-0217, USA
| | - Hsing-Pang Hsieh
- Institute of Biotechnology and Pharmaceutical Research, National Health Research Institutes, Miaoli County, 35053, Taiwan, ROC
| | - Shau-Hua Ueng
- Institute of Biotechnology and Pharmaceutical Research, National Health Research Institutes, Miaoli County, 35053, Taiwan, ROC; School of Pharmacy, College of Medicine, National Cheng Kung University, Tainan, 701, Taiwan, ROC.
| | - Shiu-Hwa Yeh
- Institute of Biotechnology and Pharmaceutical Research, National Health Research Institutes, Miaoli County, 35053, Taiwan, ROC; The Ph.D. Program in Medical Neuroscience, College of Medical Science and Technology, Taipei Medical University and National Health Research Institutes, Taipei, 110, Taiwan, ROC.
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6
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Milella MS, D'Ottavio G, De Pirro S, Barra M, Caprioli D, Badiani A. Heroin and its metabolites: relevance to heroin use disorder. Transl Psychiatry 2023; 13:120. [PMID: 37031205 PMCID: PMC10082801 DOI: 10.1038/s41398-023-02406-5] [Citation(s) in RCA: 10] [Impact Index Per Article: 10.0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 10/14/2022] [Revised: 03/17/2023] [Accepted: 03/21/2023] [Indexed: 04/10/2023] Open
Abstract
Heroin is an opioid agonist commonly abused for its rewarding effects. Since its synthesis at the end of the nineteenth century, its popularity as a recreational drug has ebbed and flowed. In the last three decades, heroin use has increased again, and yet the pharmacology of heroin is still poorly understood. After entering the body, heroin is rapidly deacetylated to 6-monoacetylmorphine (6-MAM), which is then deacetylated to morphine. Thus, drug addiction literature has long settled on the notion that heroin is little more than a pro-drug. In contrast to these former views, we will argue for a more complex interplay among heroin and its active metabolites: 6-MAM, morphine, and morphine-6-glucuronide (M6G). In particular, we propose that the complex temporal pattern of heroin effects results from the sequential, only partially overlapping, actions not only of 6-MAM, morphine, and M6G, but also of heroin per se, which, therefore, should not be seen as a mere brain-delivery system for its active metabolites. We will first review the literature concerning the pharmacokinetics and pharmacodynamics of heroin and its metabolites, then examine their neural and behavioral effects, and finally discuss the possible implications of these data for a better understanding of opioid reward and heroin addiction. By so doing we hope to highlight research topics to be investigated by future clinical and pre-clinical studies.
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Affiliation(s)
- Michele Stanislaw Milella
- Toxicology Unit, Policlinico Umberto I University Hospital, Rome, Italy.
- Laboratory affiliated to the Institute Pasteur Italia-Fondazione Cenci Bolognetti-Department of Physiology and Pharmacology, Sapienza University of Rome, Rome, Italy.
| | - Ginevra D'Ottavio
- Laboratory affiliated to the Institute Pasteur Italia-Fondazione Cenci Bolognetti-Department of Physiology and Pharmacology, Sapienza University of Rome, Rome, Italy
- Santa Lucia Foundation (IRCCS Fondazione Santa Lucia), Rome, Italy
| | - Silvana De Pirro
- Laboratory affiliated to the Institute Pasteur Italia-Fondazione Cenci Bolognetti-Department of Physiology and Pharmacology, Sapienza University of Rome, Rome, Italy
- Norwegian Centre for Addiction Research (SERAF), Faculty of Medicine, University of Oslo, Oslo, Norway
- Sussex Addiction and Intervention Centre (SARIC), School of Psychology, University of Sussex, Brighton, UK
| | | | - Daniele Caprioli
- Laboratory affiliated to the Institute Pasteur Italia-Fondazione Cenci Bolognetti-Department of Physiology and Pharmacology, Sapienza University of Rome, Rome, Italy.
- Santa Lucia Foundation (IRCCS Fondazione Santa Lucia), Rome, Italy.
| | - Aldo Badiani
- Laboratory affiliated to the Institute Pasteur Italia-Fondazione Cenci Bolognetti-Department of Physiology and Pharmacology, Sapienza University of Rome, Rome, Italy.
- Sussex Addiction and Intervention Centre (SARIC), School of Psychology, University of Sussex, Brighton, UK.
- Fondazione Villa Maraini, Rome, Italy.
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7
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Benzo[b]thiophene-2-carboxamides as novel opioid receptor agonists with potent analgesic effect and reduced constipation. Eur J Med Chem 2022; 243:114728. [DOI: 10.1016/j.ejmech.2022.114728] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/30/2022] [Revised: 08/24/2022] [Accepted: 08/25/2022] [Indexed: 11/19/2022]
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8
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Exploring Pharmacological Functions of Alternatively Spliced Variants of the Mu Opioid Receptor Gene, Oprm1, via Gene-Targeted Animal Models. Int J Mol Sci 2022; 23:ijms23063010. [PMID: 35328429 PMCID: PMC8950057 DOI: 10.3390/ijms23063010] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/29/2022] [Revised: 02/19/2022] [Accepted: 02/21/2022] [Indexed: 02/01/2023] Open
Abstract
The mu opioid receptor has a distinct place in the opioid receptor family, since it mediates the actions of most opioids used clinically (e.g., morphine and fentanyl), as well as drugs of abuse (e.g., heroin). The single-copy mu opioid receptor gene, OPRM1, goes through extensive alternative pre-mRNA splicing to generate numerous splice variants that are conserved from rodents to humans. These OPRM1 splice variants can be classified into three structurally distinct types: (1) full-length 7 transmembrane (TM) carboxyl (C)-terminal variants; (2) truncated 6TM variants; and (3) single TM variants. Distinct pharmacological functions of these splice variants have been demonstrated by both in vitro and in vivo studies, particularly by using several unique gene-targeted mouse models. These studies provide new insights into our understanding of the complex actions of mu opioids with regard to OPRM1 alternative splicing. This review provides an overview of the studies that used these gene-targeted mouse models for exploring the functional importance of Oprm1 splice variants.
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Brown TG, Xu J, Hurd YL, Pan YX. Dysregulated expression of the alternatively spliced variant mRNAs of the mu opioid receptor gene, OPRM1, in the medial prefrontal cortex of male human heroin abusers and heroin self-administering male rats. J Neurosci Res 2022; 100:35-47. [PMID: 32506472 PMCID: PMC8143898 DOI: 10.1002/jnr.24640] [Citation(s) in RCA: 18] [Impact Index Per Article: 9.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/21/2020] [Revised: 04/20/2020] [Accepted: 04/27/2020] [Indexed: 11/08/2022]
Abstract
Heroin, a mu agonist, acts through the mu opioid receptor. The mu opioid receptor gene, OPRM1, undergoes extensive alternative splicing, creating an array of splice variants that are conserved from rodent to humans. Increasing evidence suggests that these OPRM1 splice variants are pharmacologically important in mediating various actions of mu opioids, including analgesia, tolerance, physical dependence, rewarding behavior, as well as addiction. In the present study, we examine expression of the OPRM1 splice variant mRNAs in the medial prefrontal cortex (mPFC), one of the major brain regions involved in decision-making and drug-seeking behaviors, of male human heroin abusers and male rats that developed stable heroin-seeking behavior using an intravenous heroin self-administration (SA) model. The results show similar expression profiles among multiple OPRM1 splice variants in both human control subjects and saline control rats, illustrating conservation of OPRM1 alternative splicing from rodent to humans. Moreover, the expressions of several OPRM1 splice variant mRNAs were dysregulated in the postmortem mPFCs from heroin abusers compared to the control subjects. Similar patterns were observed in the rat heroin SA model. These findings suggest potential roles of the OPRM1 splice variants in heroin addiction that could be mechanistically explored using the rat heroin SA model.
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Affiliation(s)
- Taylor G Brown
- Department of Neurology and the Molecular Pharmacology Program, Memorial Sloan-Kettering Cancer Center, New York, NY, USA
| | - Jin Xu
- Department of Neurology and the Molecular Pharmacology Program, Memorial Sloan-Kettering Cancer Center, New York, NY, USA
| | - Yasmin L Hurd
- Department of Psychiatry, Icahn School of Medicine at Mount Sinai, New York, NY, USA
- Department of Neuroscience, Icahn School of Medicine at Mount Sinai, New York, NY, USA
| | - Ying-Xian Pan
- Department of Neurology and the Molecular Pharmacology Program, Memorial Sloan-Kettering Cancer Center, New York, NY, USA
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10
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Paul AK, Smith CM, Rahmatullah M, Nissapatorn V, Wilairatana P, Spetea M, Gueven N, Dietis N. Opioid Analgesia and Opioid-Induced Adverse Effects: A Review. Pharmaceuticals (Basel) 2021; 14:1091. [PMID: 34832873 PMCID: PMC8620360 DOI: 10.3390/ph14111091] [Citation(s) in RCA: 70] [Impact Index Per Article: 23.3] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/23/2021] [Revised: 10/26/2021] [Accepted: 10/26/2021] [Indexed: 01/08/2023] Open
Abstract
Opioids are widely used as therapeutic agents against moderate to severe acute and chronic pain. Still, these classes of analgesic drugs have many potential limitations as they induce analgesic tolerance, addiction and numerous behavioural adverse effects that often result in patient non-compliance. As opium and opioids have been traditionally used as painkillers, the exact mechanisms of their adverse reactions over repeated use are multifactorial and not fully understood. Older adults suffer from cancer and non-cancer chronic pain more than younger adults, due to the physiological changes related to ageing and their reduced metabolic capabilities and thus show an increased number of adverse reactions to opioid drugs. All clinically used opioids are μ-opioid receptor agonists, and the major adverse effects are directly or potentially connected to this receptor. Multifunctional opioid ligands or peripherally restricted opioids may elicit fewer adverse effects, as shown in preclinical studies, but these results need reproducibility from further extensive clinical trials. The current review aims to overview various mechanisms involved in the adverse effects induced by opioids, to provide a better understanding of the underlying pathophysiology and, ultimately, to help develop an effective therapeutic strategy to better manage pain.
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Affiliation(s)
- Alok K. Paul
- School of Pharmacy and Pharmacology, University of Tasmania, Hobart, TAS 7001, Australia;
| | - Craig M. Smith
- School of Medicine, Institute for Mental and Physical Health and Clinical Translation, Deakin University, Geelong, VIC 3216, Australia;
| | - Mohammed Rahmatullah
- Department of Biotechnology & Genetic Engineering, University of Development Alternative, Dhanmondi, Dhaka 1207, Bangladesh;
| | - Veeranoot Nissapatorn
- School of Allied Health Sciences, World Union for Herbal Drug Discovery (WUHeDD) and Research Excellence Center for Innovation and Health Products (RECIHP), Walailak University, Nakhon Si Thammarat 80160, Thailand;
| | - Polrat Wilairatana
- Department of Clinical Tropical Medicine, Faculty of Tropical Medicine, Mahidol University, Bangkok 10400, Thailand
| | - Mariana Spetea
- Department of Pharmaceutical Chemistry, Institute of Pharmacy and Center for Molecular Biosciences (CMBI), University of Innsbruck, Innrain 80–82, 6020 Innsbruck, Austria;
| | - Nuri Gueven
- School of Pharmacy and Pharmacology, University of Tasmania, Hobart, TAS 7001, Australia;
| | - Nikolas Dietis
- Medical School, University of Cyprus, Nicosia 1678, Cyprus;
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11
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Liu S, Kang WJ, Abrimian A, Xu J, Cartegni L, Majumdar S, Hesketh P, Bekker A, Pan YX. Alternative Pre-mRNA Splicing of the Mu Opioid Receptor Gene, OPRM1: Insight into Complex Mu Opioid Actions. Biomolecules 2021; 11:biom11101525. [PMID: 34680158 PMCID: PMC8534031 DOI: 10.3390/biom11101525] [Citation(s) in RCA: 13] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/30/2021] [Revised: 10/11/2021] [Accepted: 10/11/2021] [Indexed: 12/03/2022] Open
Abstract
Most opioid analgesics used clinically, including morphine and fentanyl, as well as the recreational drug heroin, act primarily through the mu opioid receptor, a class A Rhodopsin-like G protein-coupled receptor (GPCR). The single-copy mu opioid receptor gene, OPRM1, undergoes extensive alternative splicing, creating multiple splice variants or isoforms via a variety of alternative splicing events. These OPRM1 splice variants can be categorized into three major types based on the receptor structure: (1) full-length 7 transmembrane (TM) C-terminal variants; (2) truncated 6TM variants; and (3) single TM variants. Increasing evidence suggests that these OPRM1 splice variants are pharmacologically important in mediating the distinct actions of various mu opioids. More importantly, the OPRM1 variants can be targeted for development of novel opioid analgesics that are potent against multiple types of pain, but devoid of many side-effects associated with traditional opiates. In this review, we provide an overview of OPRM1 alternative splicing and its functional relevance in opioid pharmacology.
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Affiliation(s)
- Shan Liu
- Department of Anesthesiology, Rutgers New Jersey Medical School, Newark, NJ 07103, USA; (S.L.); (W.-J.K.); (A.A.); (J.X.); (P.H.); (A.B.)
| | - Wen-Jia Kang
- Department of Anesthesiology, Rutgers New Jersey Medical School, Newark, NJ 07103, USA; (S.L.); (W.-J.K.); (A.A.); (J.X.); (P.H.); (A.B.)
| | - Anna Abrimian
- Department of Anesthesiology, Rutgers New Jersey Medical School, Newark, NJ 07103, USA; (S.L.); (W.-J.K.); (A.A.); (J.X.); (P.H.); (A.B.)
| | - Jin Xu
- Department of Anesthesiology, Rutgers New Jersey Medical School, Newark, NJ 07103, USA; (S.L.); (W.-J.K.); (A.A.); (J.X.); (P.H.); (A.B.)
| | - Luca Cartegni
- Department of Chemical Biology, Ernest Mario School of Pharmacy Rutgers University, Piscataway, NJ 08854, USA;
| | - Susruta Majumdar
- Center for Clinical Pharmacology, University of Health Sciences & Pharmacy and Washington University School of Medicine, St. Louis, MO 63110, USA;
| | - Patrick Hesketh
- Department of Anesthesiology, Rutgers New Jersey Medical School, Newark, NJ 07103, USA; (S.L.); (W.-J.K.); (A.A.); (J.X.); (P.H.); (A.B.)
| | - Alex Bekker
- Department of Anesthesiology, Rutgers New Jersey Medical School, Newark, NJ 07103, USA; (S.L.); (W.-J.K.); (A.A.); (J.X.); (P.H.); (A.B.)
| | - Ying-Xian Pan
- Department of Anesthesiology, Rutgers New Jersey Medical School, Newark, NJ 07103, USA; (S.L.); (W.-J.K.); (A.A.); (J.X.); (P.H.); (A.B.)
- Correspondence: ; Tel.: +1-973-972-3213
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12
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Arttamangkul S, Platt EJ, Carroll J, Farrens D. Functional independence of endogenous µ- and δ-opioid receptors co-expressed in cholinergic interneurons. eLife 2021; 10:69740. [PMID: 34477106 PMCID: PMC8718112 DOI: 10.7554/elife.69740] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/17/2021] [Accepted: 08/31/2021] [Indexed: 12/18/2022] Open
Abstract
Class A G-protein-coupled receptors (GPCRs) normally function as monomers, although evidence from heterologous expression systems suggests that they may sometimes form homodimers and/or heterodimers. This study aims to evaluate possible functional interplay of endogenous µ- and δ-opioid receptors (MORs and DORs) in mouse neurons. Detecting GPCR dimers in native tissues, however, has been challenging. Previously, MORs and DORs co-expressed in transfected cells have been reported to form heterodimers, and their possible co-localization in neurons has been studied in knock-in mice expressing genetically engineered receptors fused to fluorescent proteins. Here, we find that single cholinergic neurons in the mouse striatum endogenously express both MORs and DORs. The receptors on neurons from live brain slices were fluorescently labeled with a ligand-directed labeling reagent, NAI-A594. The selective activation of MORs and DORs, with DAMGO (µ-agonist) and deltorphin (δ-agonist) inhibited spontaneous firing in all cells examined. In the continued presence of agonist, the firing rate returned to baseline as the result of receptor desensitization with the application of deltorphin but was less observed with the application of DAMGO. In addition, agonist-induced internalization of DORs but not MORs was detected. When MORs and DORs were activated simultaneously with [Met5]-enkephalin, desensitization of MORs was facilitated but internalization was not increased. Together, these results indicate that while MORs and DORs are expressed in single striatal cholinergic interneurons, the two receptors function independently.
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Affiliation(s)
| | - Emily J Platt
- Department of Biochemistry and Molecular Biology, Oregon Health and Science University, Portland, United States
| | - James Carroll
- Surgery, Oregon Health and Science University, Portland, United States
| | - David Farrens
- Department of Biochemistry and Molecular Biology, School of Medicine, Oregon Health and Science University, Portland, United States
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13
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Rossi GC, Bodnar RJ. Interactive Mechanisms of Supraspinal Sites of Opioid Analgesic Action: A Festschrift to Dr. Gavril W. Pasternak. Cell Mol Neurobiol 2021; 41:863-897. [PMID: 32970288 DOI: 10.1007/s10571-020-00961-9] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/26/2020] [Accepted: 09/03/2020] [Indexed: 12/30/2022]
Abstract
Almost a half century of research has elaborated the discoveries of the central mechanisms governing the analgesic responses of opiates, including their receptors, endogenous peptides, genes and their putative spinal and supraspinal sites of action. One of the central tenets of "gate-control theories of pain" was the activation of descending supraspinal sites by opiate drugs and opioid peptides thereby controlling further noxious input. This review in the Special Issue dedicated to the research of Dr. Gavril Pasternak indicates his contributions to the understanding of supraspinal mediation of opioid analgesic action within the context of the large body of work over this period. This review will examine (a) the relevant supraspinal sites mediating opioid analgesia, (b) the opioid receptor subtypes and opioid peptides involved, (c) supraspinal site analgesic interactions and their underlying neurophysiology, (d) molecular (particularly AS) tools identifying opioid receptor actions, and (e) relevant physiological variables affecting site-specific opioid analgesia. This review will build on classic initial studies, specify the contributions that Gavril Pasternak and his colleagues did in this specific area, and follow through with studies up to the present.
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Affiliation(s)
- Grace C Rossi
- Department of Psychology, C.W. Post College, Long Island University, Post Campus, Brookville, NY, USA.
| | - Richard J Bodnar
- Department of Psychology, Queens College of the City University of New York, Flushing, NY, USA
- CUNY Neuroscience Collaborative, Graduate Center, CUNY, New York, NY, USA
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14
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Muralidharan A, Samoshkin A, Convertino M, Piltonen MH, Gris P, Wang J, Jiang C, Klares R, Linton A, Ji RR, Maixner W, Dokholyan NV, Mogil JS, Diatchenko L. Identification and characterization of novel candidate compounds targeting 6- and 7-transmembrane μ-opioid receptor isoforms. Br J Pharmacol 2021; 178:2709-2726. [PMID: 33782947 PMCID: PMC10697213 DOI: 10.1111/bph.15463] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/18/2020] [Revised: 03/15/2021] [Accepted: 03/18/2021] [Indexed: 01/02/2023] Open
Abstract
BACKGROUND AND PURPOSE The μ-opioid receptor (μ receptor) is the primary target for opioid analgesics. The 7-transmembrane (TM) and 6TM μ receptor isoforms mediate inhibitory and excitatory cellular effects. Here, we developed compounds selective for 6TM- or 7TM-μ receptors to further our understanding of the pharmacodynamic properties of μ receptors. EXPERIMENTAL APPROACH We performed virtual screening of the ZINC Drug Now library of compounds using in silico 7TM- and 6TM-μ receptor structural models and identified potential compounds that are selective for 6TM- and/or 7TM-μ receptors. Subsequently, we characterized the most promising candidate compounds in functional in vitro studies using Be2C neuroblastoma transfected cells, behavioural in vivo pain assays using various knockout mice and in ex vivo electrophysiology studies. KEY RESULTS Our virtual screen identified 30 potential candidate compounds. Subsequent functional in vitro cellular assays shortlisted four compounds (#5, 10, 11 and 25) that demonstrated 6TM- or 7TM-μ receptor-dependent NO release. In in vivo pain assays these compounds also produced dose-dependent hyperalgesic responses. Studies using mice that lack specific opioid receptors further established the μ receptor-dependent nature of identified novel ligands. Ex vivo electrophysiological studies on spontaneous excitatory postsynaptic currents in isolated spinal cord slices also validated the hyperalgesic properties of the most potent 6TM- (#10) and 7TM-μ receptor (#5) ligands. CONCLUSION AND IMPLICATIONS Our novel compounds represent a new class of ligands for μ receptors and will serve as valuable research tools to facilitate the development of opioids with significant analgesic efficacy and fewer side-effects.
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Affiliation(s)
- Arjun Muralidharan
- Alan Edwards Centre for Research on Pain, McGill University, Montreal, Quebec, Canada
- Department of Psychology, McGill University, Montreal, Quebec, Canada
| | - Alexander Samoshkin
- Alan Edwards Centre for Research on Pain, McGill University, Montreal, Quebec, Canada
- Department of Anesthesia, McGill University, Montreal, Quebec, Canada
| | - Marino Convertino
- Department of Biochemistry and Biophysics, University of North Carolina, Chapel Hill, North Carolina, USA
| | - Marjo Hannele Piltonen
- Alan Edwards Centre for Research on Pain, McGill University, Montreal, Quebec, Canada
- Faculty of Dentistry, McGill University, Montreal, Quebec, Canada
| | - Pavel Gris
- Alan Edwards Centre for Research on Pain, McGill University, Montreal, Quebec, Canada
- Faculty of Dentistry, McGill University, Montreal, Quebec, Canada
| | - Jian Wang
- Department of Pharmacology, and Biochemistry & Molecular Biology, Penn State College of Medicine, Hershey, Pennsylvania, USA
| | - Changyu Jiang
- Center for Translational Pain Medicine, Department of Anesthesiology, Duke University Medical Center, Durham, North Carolina, USA
| | - Richard Klares
- Alan Edwards Centre for Research on Pain, McGill University, Montreal, Quebec, Canada
- Department of Anesthesia, McGill University, Montreal, Quebec, Canada
- Faculty of Dentistry, McGill University, Montreal, Quebec, Canada
| | - Alexander Linton
- Alan Edwards Centre for Research on Pain, McGill University, Montreal, Quebec, Canada
- Department of Anesthesia, McGill University, Montreal, Quebec, Canada
- Faculty of Dentistry, McGill University, Montreal, Quebec, Canada
| | - Ru-Rong Ji
- Center for Translational Pain Medicine, Department of Anesthesiology, Duke University Medical Center, Durham, North Carolina, USA
- Department of Neurobiology, Duke University Medical Center, Durham, North Carolina, USA
- Department of Cell Biology, Duke University Medical Center, Durham, North Carolina, USA
| | - William Maixner
- Department of Neurobiology, Duke University Medical Center, Durham, North Carolina, USA
| | - Nikolay V. Dokholyan
- Department of Biochemistry and Biophysics, University of North Carolina, Chapel Hill, North Carolina, USA
- Department of Pharmacology, and Biochemistry & Molecular Biology, Penn State College of Medicine, Hershey, Pennsylvania, USA
| | - Jeffrey S. Mogil
- Alan Edwards Centre for Research on Pain, McGill University, Montreal, Quebec, Canada
- Department of Psychology, McGill University, Montreal, Quebec, Canada
- Department of Anesthesia, McGill University, Montreal, Quebec, Canada
| | - Luda Diatchenko
- Alan Edwards Centre for Research on Pain, McGill University, Montreal, Quebec, Canada
- Department of Anesthesia, McGill University, Montreal, Quebec, Canada
- Faculty of Dentistry, McGill University, Montreal, Quebec, Canada
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15
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Chakrabarti S, Liu NJ, Gintzler AR. Relevance of Mu-Opioid Receptor Splice Variants and Plasticity of Their Signaling Sequelae to Opioid Analgesic Tolerance. Cell Mol Neurobiol 2021; 41:855-862. [PMID: 32804312 DOI: 10.1007/s10571-020-00934-y] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/21/2020] [Accepted: 08/01/2020] [Indexed: 10/23/2022]
Abstract
Opioid dose escalation to effectively control pain is often linked to the current prescription opioid abuse epidemic. This creates social as well as medical imperatives to better understand the mechanistic underpinnings of opioid tolerance to develop interventions that minimize it, thereby maximizing the analgesic effectiveness of opioids. Profound opioid analgesic tolerance can be observed in the absence of mu-opioid receptor (MOR) downregulation, aggregate MOR G protein uncoupling, and MOR desensitization, in the absence of impaired G protein coupled receptor kinase phosphorylation, arrestin binding, or endocytosis. Thus, we have explored alternative biochemical sequelae that might better account for opioid analgesic tolerance. Our findings indicate that substantial plasticity among upstream and downstream components of opioid receptor signaling and the emergence of alternative signaling pathways are major contributors to opioid analgesic tolerance. An exemplar of this plasticity is our findings that chronic morphine upregulates the MOR variants MOR-1B2 and MOR-1C1 and phosphorylation of their C-terminal sites not present in MOR-1, events causally associated with the chronic morphine-induced shift in MOR G protein coupling from predominantly Gi/Go inhibitory to Gs-stimulatory adenylyl cyclase signaling. The unique feature(s) of these variants that underlies their susceptibility to adapting to chronic morphine by altering the nature of their G protein coupling reveals the richness and pliability of MOR signaling that is enabled by generating a wide diversity of MOR variants. Furthermore, given differential anatomical expression patterns of MOR variants, MOR splice variant-dependent adaptations to chronic morphine could enable mechanistic underpinnings of tolerance and dependence that are CNS region- and cell-specific.
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Affiliation(s)
- Sumita Chakrabarti
- Department Obstetrics and Gynecology, SUNY Downstate Health Sciences University, 450 Clarkson Ave, Brooklyn, NY, 11203, USA
| | - Nai-Jiang Liu
- Department Obstetrics and Gynecology, SUNY Downstate Health Sciences University, 450 Clarkson Ave, Brooklyn, NY, 11203, USA
| | - Alan R Gintzler
- Department Obstetrics and Gynecology, SUNY Downstate Health Sciences University, 450 Clarkson Ave, Brooklyn, NY, 11203, USA.
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16
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Bhowmik S, Galeta J, Havel V, Nelson M, Faouzi A, Bechand B, Ansonoff M, Fiala T, Hunkele A, Kruegel AC, Pintar JE, Majumdar S, Javitch JA, Sames D. Site selective C-H functionalization of Mitragyna alkaloids reveals a molecular switch for tuning opioid receptor signaling efficacy. Nat Commun 2021; 12:3858. [PMID: 34158473 PMCID: PMC8219695 DOI: 10.1038/s41467-021-23736-2] [Citation(s) in RCA: 21] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/02/2020] [Accepted: 05/13/2021] [Indexed: 12/25/2022] Open
Abstract
Mitragynine (MG) is the most abundant alkaloid component of the psychoactive plant material "kratom", which according to numerous anecdotal reports shows efficacy in self-medication for pain syndromes, depression, anxiety, and substance use disorders. We have developed a synthetic method for selective functionalization of the unexplored C11 position of the MG scaffold (C6 position in indole numbering) via the use of an indole-ethylene glycol adduct and subsequent iridium-catalyzed borylation. Through this work we discover that C11 represents a key locant for fine-tuning opioid receptor signaling efficacy. 7-Hydroxymitragynine (7OH), the parent compound with low efficacy on par with buprenorphine, is transformed to an even lower efficacy agonist by introducing a fluorine substituent in this position (11-F-7OH), as demonstrated in vitro at both mouse and human mu opioid receptors (mMOR/hMOR) and in vivo in mouse analgesia tests. Low efficacy opioid agonists are of high interest as candidates for generating safer opioid medications with mitigated adverse effects.
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Affiliation(s)
- Srijita Bhowmik
- Department of Chemistry, Columbia University, New York, NY, USA
| | - Juraj Galeta
- Department of Chemistry, Columbia University, New York, NY, USA
- Institute of Organic Chemistry and Biochemistry of the Czech Academy of Sciences (IOCB Prague), 160 00, Prague 6, Czech Republic
| | - Václav Havel
- Department of Chemistry, Columbia University, New York, NY, USA
| | - Melissa Nelson
- Department of Psychiatry, and Department of Molecular Pharmacology and Therapeutics, Columbia University, New York, NY, USA
- Division of Molecular Therapeutics, New York State Psychiatric Institute, New York, NY, USA
| | - Abdelfattah Faouzi
- Center for Clinical Pharmacology, St Louis College of Pharmacy and Washington University School of Medicine, St Louis, MO, 63110, USA
- University of California San Diego, La Jolla, CA, 92161, USA
| | | | - Mike Ansonoff
- Department of Neuroscience and Cell Biology, Rutgers University, New Jersey, NJ, 08854, USA
| | - Tomas Fiala
- Department of Chemistry, Columbia University, New York, NY, USA
- Laboratory of Organic Chemistry, ETH Zürich, 8093, Zürich, Switzerland
| | - Amanda Hunkele
- Center for Clinical Pharmacology, St Louis College of Pharmacy and Washington University School of Medicine, St Louis, MO, 63110, USA
- Department of Neurology and Molecular Pharmacology, Memorial Sloan Kettering Cancer Center, New York, NY, 10021, USA
| | | | - John E Pintar
- Department of Neuroscience and Cell Biology, Rutgers University, New Jersey, NJ, 08854, USA
| | - Susruta Majumdar
- Center for Clinical Pharmacology, St Louis College of Pharmacy and Washington University School of Medicine, St Louis, MO, 63110, USA
| | - Jonathan A Javitch
- Department of Psychiatry, and Department of Molecular Pharmacology and Therapeutics, Columbia University, New York, NY, USA
- Division of Molecular Therapeutics, New York State Psychiatric Institute, New York, NY, USA
| | - Dalibor Sames
- Department of Chemistry, Columbia University, New York, NY, USA.
- NeuroTechnology Center at Columbia University, New York, NY, USA.
- The Zuckerman Mind Brain Behavior Institute at Columbia University, New York, NY, USA.
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17
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Morphine produces potent antinociception, sedation, and hypothermia in humanized mice expressing human mu-opioid receptor splice variants. Pain 2021; 161:1177-1190. [PMID: 32040076 DOI: 10.1097/j.pain.0000000000001823] [Citation(s) in RCA: 6] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/11/2022]
Abstract
Morphine is a strong painkiller acting through mu-opioid receptor (MOR). Full-length 7-transmembrane (TM) variants of MOR share similar amino acid sequences of TM domains in rodents and humans; however, interspecies differences in N- and C-terminal amino acid sequences of MOR splice variants dramatically affect the downstream signaling. Thus, it is essential to develop a mouse model that expresses human MOR splice variants for opioid pharmacological studies. We generated 2 lines of fully humanized MOR mice (hMOR; mMOR mice), line #1 and #2. The novel murine model having human OPRM1 genes and human-specific variants was examined by reverse-transcription polymerase chain reaction and the MinION nanopore sequencing. The differences in the regional distribution of MOR between wild-type and humanized MOR mice brains were detected by RNAscope and radioligand binding assay. hMOR; mMOR mice were characterized in vivo using a tail-flick, charcoal meal, open field, tail suspension, naloxone precipitation tests, and rectal temperature measurement. The data indicated that wild-type and humanized MOR mice exhibited different pharmacology of morphine, including antinociception, tolerance, sedation, and withdrawal syndromes, suggesting the presence of species difference between mouse and human MORs. Therefore, hMOR; mMOR mice could serve as a novel mouse model for pharmacogenetic studies of opioids.
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18
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Jaschke N, Pählig S, Pan YX, Hofbauer LC, Göbel A, Rachner TD. From Pharmacology to Physiology: Endocrine Functions of μ-Opioid Receptor Networks. Trends Endocrinol Metab 2021; 32:306-319. [PMID: 33676828 PMCID: PMC8035298 DOI: 10.1016/j.tem.2021.02.004] [Citation(s) in RCA: 7] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 01/05/2021] [Revised: 02/08/2021] [Accepted: 02/11/2021] [Indexed: 01/04/2023]
Abstract
The steady rise in opioid users and abusers has uncovered multiple detrimental health consequences of perturbed opioid receptor signaling, thereby creating the need to better understand the biology of these systems. Among endogenous opioid networks, μ-receptors have received special attention due to their unprecedented biological complexity and broad implications in homeostatic functions. Here, we review the origin, molecular biology, and physiology of endogenous opioids with a special focus on μ-opioid receptor networks within the endocrine system. Moreover, we summarize the current evidence supporting an involvement of the latter in regulating distinct endocrine functions. Finally, we combine these insights to present an integrated perspective on μ-opioid receptor biology and provide an outlook on future studies and unresolved questions in this field.
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Affiliation(s)
- Nikolai Jaschke
- Department of Medicine III and Center for Healthy Aging, Technische Universität Dresden, Dresden, Germany.
| | - Sophie Pählig
- Department of Medicine III and Center for Healthy Aging, Technische Universität Dresden, Dresden, Germany
| | - Ying-Xian Pan
- Department of Anesthesiology, Rutgers New Jersey Medical School, Newark, NJ 07103, USA
| | - Lorenz C Hofbauer
- Department of Medicine III and Center for Healthy Aging, Technische Universität Dresden, Dresden, Germany
| | - Andy Göbel
- Department of Medicine III and Center for Healthy Aging, Technische Universität Dresden, Dresden, Germany
| | - Tilman D Rachner
- Department of Medicine III and Center for Healthy Aging, Technische Universität Dresden, Dresden, Germany
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19
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Abrimian A, Kraft T, Pan YX. Endogenous Opioid Peptides and Alternatively Spliced Mu Opioid Receptor Seven Transmembrane Carboxyl-Terminal Variants. Int J Mol Sci 2021; 22:3779. [PMID: 33917474 PMCID: PMC8038826 DOI: 10.3390/ijms22073779] [Citation(s) in RCA: 12] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/21/2021] [Revised: 04/02/2021] [Accepted: 04/04/2021] [Indexed: 12/20/2022] Open
Abstract
There exist three main types of endogenous opioid peptides, enkephalins, dynorphins and β-endorphin, all of which are derived from their precursors. These endogenous opioid peptides act through opioid receptors, including mu opioid receptor (MOR), delta opioid receptor (DOR) and kappa opioid receptor (KOR), and play important roles not only in analgesia, but also many other biological processes such as reward, stress response, feeding and emotion. The MOR gene, OPRM1, undergoes extensive alternative pre-mRNA splicing, generating multiple splice variants or isoforms. One type of these splice variants, the full-length 7 transmembrane (TM) Carboxyl (C)-terminal variants, has the same receptor structures but contains different intracellular C-terminal tails. The pharmacological functions of several endogenous opioid peptides through the mouse, rat and human OPRM1 7TM C-terminal variants have been considerably investigated together with various mu opioid ligands. The current review focuses on the studies of these endogenous opioid peptides and summarizes the results from early pharmacological studies, including receptor binding affinity and G protein activation, and recent studies of β-arrestin2 recruitment and biased signaling, aiming to provide new insights into the mechanisms and functions of endogenous opioid peptides, which are mediated through the OPRM1 7TM C-terminal splice variants.
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Affiliation(s)
| | | | - Ying-Xian Pan
- Department of Anesthesiology, Rutgers New Jersey Medical School, Newark, NJ 07103, USA; (A.A.); (T.K.)
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20
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Zhou P, Li Y, Yong Z, Chen M, Zhang Y, Su R, Gong Z. Thienorphine induces antinociception without dependence through activation of κ- and δ-, and partial activation of μ- opioid receptor. Brain Res 2020; 1748:147083. [DOI: 10.1016/j.brainres.2020.147083] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/22/2020] [Revised: 08/21/2020] [Accepted: 08/24/2020] [Indexed: 12/25/2022]
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21
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Faouzi A, Uprety R, Gomes I, Massaly N, Keresztes AI, Le Rouzic V, Gupta A, Zhang T, Yoon HJ, Ansonoff M, Allaoa A, Pan YX, Pintar J, Morón JA, Streicher JM, Devi LA, Majumdar S. Synthesis and Pharmacology of a Novel μ-δ Opioid Receptor Heteromer-Selective Agonist Based on the Carfentanyl Template. J Med Chem 2020; 63:13618-13637. [PMID: 33170687 DOI: 10.1021/acs.jmedchem.0c00901] [Citation(s) in RCA: 17] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/20/2022]
Abstract
In this work, we studied a series of carfentanyl amide-based opioid derivatives targeting the mu opioid receptor (μOR) and the delta opioid receptor (δOR) heteromer as a credible novel target in pain management therapy. We identified a lead compound named MP135 that exhibits high G-protein activity at μ-δ heteromers compared to the homomeric δOR or μOR and low β-arrestin2 recruitment activity at all three. Furthermore, MP135 exhibits distinct signaling profile, as compared to the previously identified agonist targeting μ-δ heteromers, CYM51010. Pharmacological characterization of MP135 supports the utility of this compound as a molecule that could be developed as an antinociceptive agent similar to morphine in rodents. In vivo characterization reveals that MP135 maintains untoward side effects such as respiratory depression and reward behavior; together, these results suggest that optimization of MP135 is necessary for the development of therapeutics that suppress the classical side effects associated with conventional clinical opioids.
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Affiliation(s)
- Abdelfattah Faouzi
- Center for Clinical Pharmacology, St Louis College of Pharmacy and Washington University, School of Medicine, St. Louis, Missouri 63110, United States.,Department of Anesthesiology, Washington University School of Medicine, St. Louis, Missouri 63110, United States
| | - Rajendra Uprety
- Department of Neurology and Molecular Pharmacology, Memorial Sloan Kettering Cancer Center, New York, New York 10065, United States
| | - Ivone Gomes
- Department of Pharmacological Sciences, Icahn School of Medicine at Mount Sinai, New York, New York 10029, United States
| | - Nicolas Massaly
- Department of Anesthesiology, Washington University School of Medicine, St. Louis, Missouri 63110, United States
| | - Attila I Keresztes
- Department of Pharmacology, College of Medicine, University of Arizona, Tucson, Arkansas 85724, United States
| | - Valerie Le Rouzic
- Department of Neurology and Molecular Pharmacology, Memorial Sloan Kettering Cancer Center, New York, New York 10065, United States
| | - Achla Gupta
- Department of Pharmacological Sciences, Icahn School of Medicine at Mount Sinai, New York, New York 10029, United States
| | - Tiffany Zhang
- Department of Neurology and Molecular Pharmacology, Memorial Sloan Kettering Cancer Center, New York, New York 10065, United States
| | - Hye Jean Yoon
- Department of Anesthesiology, Washington University School of Medicine, St. Louis, Missouri 63110, United States
| | - Michael Ansonoff
- Department of Neuroscience and Cell Biology, Rutgers Robert Wood Johnson Medical School, Piscataway, New Jersey 08854, United States
| | - Abdullah Allaoa
- Department of Neurology and Molecular Pharmacology, Memorial Sloan Kettering Cancer Center, New York, New York 10065, United States
| | - Ying Xian Pan
- Department of Neurology and Molecular Pharmacology, Memorial Sloan Kettering Cancer Center, New York, New York 10065, United States
| | - John Pintar
- Department of Neuroscience and Cell Biology, Rutgers Robert Wood Johnson Medical School, Piscataway, New Jersey 08854, United States
| | - Jose A Morón
- Department of Anesthesiology, Washington University School of Medicine, St. Louis, Missouri 63110, United States.,Department of Neuroscience and Psychiatry, Washington University School of Medicine, St. Louis, Missouri 63110, United States
| | - John M Streicher
- Department of Pharmacology, College of Medicine, University of Arizona, Tucson, Arkansas 85724, United States
| | - Lakshmi A Devi
- Department of Pharmacological Sciences, Icahn School of Medicine at Mount Sinai, New York, New York 10029, United States
| | - Susruta Majumdar
- Center for Clinical Pharmacology, St Louis College of Pharmacy and Washington University, School of Medicine, St. Louis, Missouri 63110, United States.,Department of Anesthesiology, Washington University School of Medicine, St. Louis, Missouri 63110, United States
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22
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Meng F, Li Y, Sun H, Li C, Li Q, Law PY, Loh HH, Liang L, Zheng H. Naloxone Facilitates Contextual Learning and Memory in a Receptor-Independent and Tet1-Dependent Manner. Cell Mol Neurobiol 2020; 41:1031-1038. [PMID: 32989585 DOI: 10.1007/s10571-020-00970-8] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/28/2020] [Accepted: 09/23/2020] [Indexed: 11/30/2022]
Abstract
Opioids, like morphine and naloxone, regulate the proliferation and neuronal differentiation of neural stem cells (NSCs) in a receptor-independent and ten-eleven translocation methylcytosine dioxygenase (TET1)-dependent manner in vitro. Whether naloxone regulates hippocampal NSCs and contextual learning in vivo in a similar manner was determined. Naloxone infusion increased the Ki67 and Doublecortin positive cells in subgranular zone of wild type mice, which suggested the increased proliferation and differentiation of hippocampal NSCs in vivo and was consistent with the in vitro functions of naloxone. In addition, naloxone infusion also facilitated the contextual learning and memory of wild type mice. To determine the contribution of μ-opioid receptor (OPRM1) and TET1 to these functions of naloxone, several types of knockout mice were used. Since Tet1-/- mice have high deficiency in contextual learning and memory, Tet1+/- mice were used instead. The abilities of naloxone to regulate NSCs and to facilitate contextual learning were significantly impaired in Tet1+/- mice. In addition, these abilities of naloxone were not affected in Oprm1-/- mice. Therefore, naloxone facilitates contextual learning and memory in a receptor-independent and Tet1-dependent manner, which provides new understanding on the receptor-independent functions of opioids.
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Affiliation(s)
- Fei Meng
- University of Science and Technology of China, Hefei, 230026, Anhui, China.,CAS Key Laboratory of Regenerative Biology, Guangzhou Institutes of Biomedicine and Health, Chinese Academy of Sciences, #190 Kaiyuan Ave., Science City, Guangzhou, 510530, China
| | - Yuan Li
- CAS Key Laboratory of Regenerative Biology, Guangzhou Institutes of Biomedicine and Health, Chinese Academy of Sciences, #190 Kaiyuan Ave., Science City, Guangzhou, 510530, China.,Bioland Laboratory (Guangzhou Regenerative Medicine and Health Guangdong Laboratory), Guangzhou, 510700, China.,Guangdong Provincial Key Laboratory of Stem Cell and Regenerative Medicine, Guangzhou, 510530, China
| | - Hao Sun
- CAS Key Laboratory of Regenerative Biology, Guangzhou Institutes of Biomedicine and Health, Chinese Academy of Sciences, #190 Kaiyuan Ave., Science City, Guangzhou, 510530, China.,University of Chinese Academy of Sciences, Beijing, 100049, China.,Bioland Laboratory (Guangzhou Regenerative Medicine and Health Guangdong Laboratory), Guangzhou, 510700, China.,Guangdong Provincial Key Laboratory of Stem Cell and Regenerative Medicine, Guangzhou, 510530, China
| | - Changpeng Li
- CAS Key Laboratory of Regenerative Biology, Guangzhou Institutes of Biomedicine and Health, Chinese Academy of Sciences, #190 Kaiyuan Ave., Science City, Guangzhou, 510530, China.,Bioland Laboratory (Guangzhou Regenerative Medicine and Health Guangdong Laboratory), Guangzhou, 510700, China.,Guangdong Provincial Key Laboratory of Stem Cell and Regenerative Medicine, Guangzhou, 510530, China
| | - Qian Li
- CAS Key Laboratory of Regenerative Biology, Guangzhou Institutes of Biomedicine and Health, Chinese Academy of Sciences, #190 Kaiyuan Ave., Science City, Guangzhou, 510530, China.,Bioland Laboratory (Guangzhou Regenerative Medicine and Health Guangdong Laboratory), Guangzhou, 510700, China.,Guangdong Provincial Key Laboratory of Stem Cell and Regenerative Medicine, Guangzhou, 510530, China.,Guangzhou Medical University, Guangzhou, 511436, China
| | - Ping-Yee Law
- Department of Pharmacology, University of Minnesota, Minneapolis, MN, 55455, USA
| | - Horace H Loh
- Bioland Laboratory (Guangzhou Regenerative Medicine and Health Guangdong Laboratory), Guangzhou, 510700, China
| | - Lining Liang
- CAS Key Laboratory of Regenerative Biology, Guangzhou Institutes of Biomedicine and Health, Chinese Academy of Sciences, #190 Kaiyuan Ave., Science City, Guangzhou, 510530, China. .,Bioland Laboratory (Guangzhou Regenerative Medicine and Health Guangdong Laboratory), Guangzhou, 510700, China. .,Guangdong Provincial Key Laboratory of Stem Cell and Regenerative Medicine, Guangzhou, 510530, China.
| | - Hui Zheng
- CAS Key Laboratory of Regenerative Biology, Guangzhou Institutes of Biomedicine and Health, Chinese Academy of Sciences, #190 Kaiyuan Ave., Science City, Guangzhou, 510530, China. .,University of Chinese Academy of Sciences, Beijing, 100049, China. .,Bioland Laboratory (Guangzhou Regenerative Medicine and Health Guangdong Laboratory), Guangzhou, 510700, China. .,Guangdong Provincial Key Laboratory of Stem Cell and Regenerative Medicine, Guangzhou, 510530, China. .,Institutes for Stem Cell and Regeneration, Chinese Academy of Sciences, Beijing, 100101, China.
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23
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Mizoguchi H, Fujii H. Exploring μ-Opioid Receptor Splice Variants as a Specific Molecular Target for New Analgesics. Curr Top Med Chem 2020; 20:2866-2877. [PMID: 32962616 DOI: 10.2174/1568026620666200922113430] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/11/2020] [Revised: 08/29/2020] [Accepted: 09/03/2020] [Indexed: 11/22/2022]
Abstract
Since a μ-opioid receptor gene containing multiple exons has been identified, the variety of splice variants for μ-opioid receptors have been reported in various species. Amidino-TAPA and IBNtxA have been discovered as new analgesics with different pharmacological profiles from morphine. These new analgesics show a very potent analgesic effect but do not have dependence liability. Interestingly, these analgesics show the selectivity to the morphine-insensitive μ-opioid receptor splice variants. The splice variants, sensitive to these new analgesics but insensitive to morphine, may be a better molecular target to develop the analgesics without side effects.
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Affiliation(s)
- Hirokazu Mizoguchi
- Department of Physiology and Anatomy, Faculty of Pharmaceutical Sciences, Tohoku Medical and Pharmaceutical University, 4-4-1 Komatsushima, Aoba-ku, Sendai 981-8558, Japan
| | - Hideaki Fujii
- Laboratory of Medicinal Chemistry and Medical Research Laboratories, School of Pharmacy, Kitasato University, 5-9-1 Shirokane, Minato-ku, Tokyo 108-8641, Japan
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24
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Zhang T, Xu J, Pan YX. A Truncated Six Transmembrane Splice Variant MOR-1G Enhances Expression of the Full-Length Seven Transmembrane μ-Opioid Receptor through Heterodimerization. Mol Pharmacol 2020; 98:518-527. [PMID: 32723770 DOI: 10.1124/mol.120.119453] [Citation(s) in RCA: 12] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/08/2020] [Accepted: 07/06/2020] [Indexed: 12/11/2022] Open
Abstract
The μ-opioid receptor gene undergoes extensive alternative splicing to generate an array of splice variants. One group of splice variants excludes the first transmembrane (TM) domain and contains six TM domains. These 6TM variants are essential for the action of a novel class of analgesic drugs, including 3-iodobenzoyl-6β-naltrexamide, which is potent against a spectrum of pain models without exhibiting the adverse side effects of traditional opiates. The 6TM variants are also involved in analgesic action through other drug classes, including δ-opioid and κ-opioids and α 2-adrenergic drugs. Of the five 6TM variants in mouse, mouse μ-opioid receptor (mMOR)-1G is abundant and conserved from rodent to human. In the present study, we demonstrate a new function of mMOR-1G in enhancing expression of the full-length 7TM μ-opioid receptor, mMOR-1. When coexpressed with mMOR-1 in a Tet-Off inducible CHO cell line, mMOR-1G has no effect on mMOR-1 mRNA expression but greatly increases mMOR-1 protein expression in a dose-dependent manner determined by opioid receptor binding and [35S] guanosine 5'-3-O-(thio)triphosphate binding. Subcellular fractionation analysis using OptiPrep density gradient centrifugation shows an increase of functional mMOR-1 receptor in plasma membrane-enriched fractions. Using a coimmunoprecipitation approach, we further demonstrate that mMOR-1G physically associates with mMOR-1 starting at the endoplasmic reticulum, suggesting a chaperone-like function. These data provide a molecular mechanism for how mMOR-1G regulates expression and function of the full-length 7TM μ-opioid receptor. SIGNIFICANCE STATEMENT: The current study establishes a novel function of mouse μ-opioid receptor (mMOR)-1G, a truncated splice variant with six transmembrane (TM) domains of the mouse μ-opioid receptor gene, in enhancing expression of the full-length 7TM mMOR-1 through a chaperone-like function.
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Affiliation(s)
- Tiffany Zhang
- Department of Neurology and the Molecular Pharmacology and Chemistry Program, Memorial Sloan-Kettering Cancer Center, New York, New York
| | - Jin Xu
- Department of Neurology and the Molecular Pharmacology and Chemistry Program, Memorial Sloan-Kettering Cancer Center, New York, New York
| | - Ying-Xian Pan
- Department of Neurology and the Molecular Pharmacology and Chemistry Program, Memorial Sloan-Kettering Cancer Center, New York, New York
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25
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Zhang XY, Dou YN, Yuan L, Li Q, Zhu YJ, Wang M, Sun YG. Different neuronal populations mediate inflammatory pain analgesia by exogenous and endogenous opioids. eLife 2020; 9:55289. [PMID: 32519950 PMCID: PMC7311172 DOI: 10.7554/elife.55289] [Citation(s) in RCA: 28] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/19/2020] [Accepted: 06/10/2020] [Indexed: 02/06/2023] Open
Abstract
Mu-opioid receptors (MORs) are crucial for analgesia by both exogenous and endogenous opioids. However, the distinct mechanisms underlying these two types of opioid analgesia remain largely unknown. Here, we demonstrate that analgesic effects of exogenous and endogenous opioids on inflammatory pain are mediated by MORs expressed in distinct subpopulations of neurons in mice. We found that the exogenous opioid-induced analgesia of inflammatory pain is mediated by MORs in Vglut2+ glutamatergic but not GABAergic neurons. In contrast, analgesia by endogenous opioids is mediated by MORs in GABAergic rather than Vglut2+ glutamatergic neurons. Furthermore, MORs expressed at the spinal level is mainly involved in the analgesic effect of morphine in acute pain, but not in endogenous opioid analgesia during chronic inflammatory pain. Thus, our study revealed distinct mechanisms underlying analgesia by exogenous and endogenous opioids, and laid the foundation for further dissecting the circuit mechanism underlying opioid analgesia.
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Affiliation(s)
- Xin-Yan Zhang
- Institute of Neuroscience, State Key Laboratory of Neuroscience, CAS Center for Excellence in Brain Science & Intelligence Technology, Chinese Academy of Sciences, Shanghai, China.,University of Chinese Academy of Sciences, Beijing, China
| | - Yan-Nong Dou
- Institute of Neuroscience, State Key Laboratory of Neuroscience, CAS Center for Excellence in Brain Science & Intelligence Technology, Chinese Academy of Sciences, Shanghai, China
| | - Lei Yuan
- Institute of Neuroscience, State Key Laboratory of Neuroscience, CAS Center for Excellence in Brain Science & Intelligence Technology, Chinese Academy of Sciences, Shanghai, China.,University of Chinese Academy of Sciences, Beijing, China
| | - Qing Li
- Institute of Neuroscience, State Key Laboratory of Neuroscience, CAS Center for Excellence in Brain Science & Intelligence Technology, Chinese Academy of Sciences, Shanghai, China
| | - Yan-Jing Zhu
- Institute of Neuroscience, State Key Laboratory of Neuroscience, CAS Center for Excellence in Brain Science & Intelligence Technology, Chinese Academy of Sciences, Shanghai, China
| | - Meng Wang
- Institute of Neuroscience, State Key Laboratory of Neuroscience, CAS Center for Excellence in Brain Science & Intelligence Technology, Chinese Academy of Sciences, Shanghai, China.,University of Chinese Academy of Sciences, Beijing, China
| | - Yan-Gang Sun
- Institute of Neuroscience, State Key Laboratory of Neuroscience, CAS Center for Excellence in Brain Science & Intelligence Technology, Chinese Academy of Sciences, Shanghai, China.,Shanghai Center for Brain Science and Brain-Inspired Intelligence Technology, Shanghai, China
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26
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Grinnell SG, Uprety R, Varadi A, Subrath J, Hunkele A, Pan YX, Pasternak GW, Majumdar S. Synthesis and Characterization of Azido Aryl Analogs of IBNtxA for Radio-Photoaffinity Labeling Opioid Receptors in Cell Lines and in Mouse Brain. Cell Mol Neurobiol 2020; 41:977-993. [PMID: 32424771 DOI: 10.1007/s10571-020-00867-6] [Citation(s) in RCA: 9] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/20/2020] [Accepted: 05/05/2020] [Indexed: 10/24/2022]
Abstract
Mu opioid receptors (MOR-1) mediate the biological actions of clinically used opioids such as morphine, oxycodone, and fentanyl. The mu opioid receptor gene, OPRM1, undergoes extensive alternative splicing, generating multiple splice variants. One type of splice variants are truncated variants containing only six transmembrane domains (6TM) that mediate the analgesic action of novel opioid drugs such as 3'-iodobenzoylnaltrexamide (IBNtxA). Previously, we have shown that IBNtxA is a potent analgesic effective in a spectrum of pain models but lacks many side-effects associated with traditional opiates. In order to investigate the targets labeled by IBNtxA, we synthesized two arylazido analogs of IBNtxA that allow photolabeling of mouse mu opioid receptors (mMOR-1) in transfected cell lines and mMOR-1 protein complexes that may comprise the 6TM sites in mouse brain. We demonstrate that both allyl and alkyne arylazido derivatives of IBNtxA efficiently radio-photolabeled mMOR-1 in cell lines and MOR-1 protein complexes expressed either exogenously or endogenously, as well as found in mouse brain. In future, design and application of such radio-photolabeling ligands with a conjugated handle will provide useful tools for further isolating or purifying MOR-1 to investigate site specific ligand-protein contacts and its signaling complexes.
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Affiliation(s)
- Steven G Grinnell
- Molecular Pharmacology and Chemistry Program, Memorial Sloan-Kettering Cancer Center, New York, NY, USA. .,Neuroscience Graduate Program, Weill Cornell Graduate School of Medical Sciences, New York, NY, USA.
| | - Rajendra Uprety
- Molecular Pharmacology and Chemistry Program, Memorial Sloan-Kettering Cancer Center, New York, NY, USA
| | - Andras Varadi
- Molecular Pharmacology and Chemistry Program, Memorial Sloan-Kettering Cancer Center, New York, NY, USA.,Neuroscience Graduate Program, Weill Cornell Graduate School of Medical Sciences, New York, NY, USA
| | - Joan Subrath
- Molecular Pharmacology and Chemistry Program, Memorial Sloan-Kettering Cancer Center, New York, NY, USA
| | - Amanda Hunkele
- Molecular Pharmacology and Chemistry Program, Memorial Sloan-Kettering Cancer Center, New York, NY, USA
| | - Ying Xian Pan
- Department of Neurology, Memorial Sloan-Kettering Cancer Center, New York, NY, USA.,Molecular Pharmacology and Chemistry Program, Memorial Sloan-Kettering Cancer Center, New York, NY, USA
| | - Gavril W Pasternak
- Department of Neurology, Memorial Sloan-Kettering Cancer Center, New York, NY, USA.,Molecular Pharmacology and Chemistry Program, Memorial Sloan-Kettering Cancer Center, New York, NY, USA.,Neuroscience Graduate Program, Weill Cornell Graduate School of Medical Sciences, New York, NY, USA.,Pharmacology Graduate Program, Weill Cornell Graduate School of Medical Sciences, New York, NY, USA
| | - Susruta Majumdar
- Center for Clinical Pharmacology, St Louis College of Pharmacy and Washington University School of Medicine, St Louis, MO, USA.
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27
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Chen J, Liang L, Li Y, Zhang Y, Zhang M, Yang T, Meng F, Lai X, Li C, He J, He M, Xu Q, Li Q, Law P, Loh HH, Pei D, Sun H, Zheng H. Naloxone regulates the differentiation of neural stem cells via a receptor‐independent pathway. FASEB J 2020; 34:5917-5930. [DOI: 10.1096/fj.201902873r] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/14/2019] [Revised: 02/24/2020] [Accepted: 02/26/2020] [Indexed: 11/11/2022]
Affiliation(s)
- Jinlong Chen
- CAS Key Laboratory of Regenerative Biology, Joint School of Life Sciences of Guangzhou Medical University Guangzhou Institutes of Biomedicine and Health, Chinese Academy of Sciences Guangzhou China
- Guangzhou Regenerative Medicine and Health Guangdong Laboratory Guangzhou China
- Guangdong Provincial Key Laboratory of Stem Cell and Regenerative Medicine Guangzhou China
- University of Chinese Academy of Sciences Beijing China
| | - Lining Liang
- CAS Key Laboratory of Regenerative Biology, Joint School of Life Sciences of Guangzhou Medical University Guangzhou Institutes of Biomedicine and Health, Chinese Academy of Sciences Guangzhou China
- Guangzhou Regenerative Medicine and Health Guangdong Laboratory Guangzhou China
- Guangdong Provincial Key Laboratory of Stem Cell and Regenerative Medicine Guangzhou China
| | - Yuan Li
- CAS Key Laboratory of Regenerative Biology, Joint School of Life Sciences of Guangzhou Medical University Guangzhou Institutes of Biomedicine and Health, Chinese Academy of Sciences Guangzhou China
- Guangzhou Regenerative Medicine and Health Guangdong Laboratory Guangzhou China
- Guangdong Provincial Key Laboratory of Stem Cell and Regenerative Medicine Guangzhou China
| | - Yixin Zhang
- CAS Key Laboratory of Regenerative Biology, Joint School of Life Sciences of Guangzhou Medical University Guangzhou Institutes of Biomedicine and Health, Chinese Academy of Sciences Guangzhou China
- Guangzhou Regenerative Medicine and Health Guangdong Laboratory Guangzhou China
- Guangdong Provincial Key Laboratory of Stem Cell and Regenerative Medicine Guangzhou China
- University of Chinese Academy of Sciences Beijing China
| | - Mengdan Zhang
- CAS Key Laboratory of Regenerative Biology, Joint School of Life Sciences of Guangzhou Medical University Guangzhou Institutes of Biomedicine and Health, Chinese Academy of Sciences Guangzhou China
- Guangzhou Regenerative Medicine and Health Guangdong Laboratory Guangzhou China
- Guangdong Provincial Key Laboratory of Stem Cell and Regenerative Medicine Guangzhou China
- University of Chinese Academy of Sciences Beijing China
| | - Tingting Yang
- CAS Key Laboratory of Regenerative Biology, Joint School of Life Sciences of Guangzhou Medical University Guangzhou Institutes of Biomedicine and Health, Chinese Academy of Sciences Guangzhou China
- Guangzhou Regenerative Medicine and Health Guangdong Laboratory Guangzhou China
- Guangdong Provincial Key Laboratory of Stem Cell and Regenerative Medicine Guangzhou China
- University of Chinese Academy of Sciences Beijing China
| | - Fei Meng
- CAS Key Laboratory of Regenerative Biology, Joint School of Life Sciences of Guangzhou Medical University Guangzhou Institutes of Biomedicine and Health, Chinese Academy of Sciences Guangzhou China
- Guangzhou Regenerative Medicine and Health Guangdong Laboratory Guangzhou China
- Guangdong Provincial Key Laboratory of Stem Cell and Regenerative Medicine Guangzhou China
- University of Chinese Academy of Sciences Beijing China
| | - Xiaowei Lai
- CAS Key Laboratory of Regenerative Biology, Joint School of Life Sciences of Guangzhou Medical University Guangzhou Institutes of Biomedicine and Health, Chinese Academy of Sciences Guangzhou China
- Guangzhou Regenerative Medicine and Health Guangdong Laboratory Guangzhou China
- Guangdong Provincial Key Laboratory of Stem Cell and Regenerative Medicine Guangzhou China
- University of Chinese Academy of Sciences Beijing China
| | - Changpeng Li
- CAS Key Laboratory of Regenerative Biology, Joint School of Life Sciences of Guangzhou Medical University Guangzhou Institutes of Biomedicine and Health, Chinese Academy of Sciences Guangzhou China
- Guangzhou Regenerative Medicine and Health Guangdong Laboratory Guangzhou China
- Guangdong Provincial Key Laboratory of Stem Cell and Regenerative Medicine Guangzhou China
| | - Jingcai He
- CAS Key Laboratory of Regenerative Biology, Joint School of Life Sciences of Guangzhou Medical University Guangzhou Institutes of Biomedicine and Health, Chinese Academy of Sciences Guangzhou China
- Guangzhou Regenerative Medicine and Health Guangdong Laboratory Guangzhou China
- Guangdong Provincial Key Laboratory of Stem Cell and Regenerative Medicine Guangzhou China
| | - Meiai He
- CAS Key Laboratory of Regenerative Biology, Joint School of Life Sciences of Guangzhou Medical University Guangzhou Institutes of Biomedicine and Health, Chinese Academy of Sciences Guangzhou China
- Guangzhou Regenerative Medicine and Health Guangdong Laboratory Guangzhou China
- Guangdong Provincial Key Laboratory of Stem Cell and Regenerative Medicine Guangzhou China
- University of Chinese Academy of Sciences Beijing China
| | - Qiaoran Xu
- CAS Key Laboratory of Regenerative Biology, Joint School of Life Sciences of Guangzhou Medical University Guangzhou Institutes of Biomedicine and Health, Chinese Academy of Sciences Guangzhou China
- Guangzhou Regenerative Medicine and Health Guangdong Laboratory Guangzhou China
- Guangdong Provincial Key Laboratory of Stem Cell and Regenerative Medicine Guangzhou China
- University of Chinese Academy of Sciences Beijing China
| | - Qian Li
- CAS Key Laboratory of Regenerative Biology, Joint School of Life Sciences of Guangzhou Medical University Guangzhou Institutes of Biomedicine and Health, Chinese Academy of Sciences Guangzhou China
| | - Ping‐Yee Law
- Department of Pharmacology University of Minnesota Minneapolis MN USA
| | - Horace H. Loh
- Guangzhou Regenerative Medicine and Health Guangdong Laboratory Guangzhou China
- Department of Pharmacology University of Minnesota Minneapolis MN USA
| | - Duanqing Pei
- CAS Key Laboratory of Regenerative Biology, Joint School of Life Sciences of Guangzhou Medical University Guangzhou Institutes of Biomedicine and Health, Chinese Academy of Sciences Guangzhou China
- Guangzhou Regenerative Medicine and Health Guangdong Laboratory Guangzhou China
- Guangdong Provincial Key Laboratory of Stem Cell and Regenerative Medicine Guangzhou China
- University of Chinese Academy of Sciences Beijing China
- Institutes for Stem Cell and Regeneration Chinese Academy of Sciences Beijing China
| | - Hao Sun
- CAS Key Laboratory of Regenerative Biology, Joint School of Life Sciences of Guangzhou Medical University Guangzhou Institutes of Biomedicine and Health, Chinese Academy of Sciences Guangzhou China
- Guangzhou Regenerative Medicine and Health Guangdong Laboratory Guangzhou China
- Guangdong Provincial Key Laboratory of Stem Cell and Regenerative Medicine Guangzhou China
- University of Chinese Academy of Sciences Beijing China
| | - Hui Zheng
- CAS Key Laboratory of Regenerative Biology, Joint School of Life Sciences of Guangzhou Medical University Guangzhou Institutes of Biomedicine and Health, Chinese Academy of Sciences Guangzhou China
- Guangzhou Regenerative Medicine and Health Guangdong Laboratory Guangzhou China
- Guangdong Provincial Key Laboratory of Stem Cell and Regenerative Medicine Guangzhou China
- University of Chinese Academy of Sciences Beijing China
- Institutes for Stem Cell and Regeneration Chinese Academy of Sciences Beijing China
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28
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Busserolles J, Lolignier S, Kerckhove N, Bertin C, Authier N, Eschalier A. Replacement of current opioid drugs focusing on MOR-related strategies. Pharmacol Ther 2020; 210:107519. [PMID: 32165137 DOI: 10.1016/j.pharmthera.2020.107519] [Citation(s) in RCA: 15] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/04/2019] [Accepted: 02/24/2020] [Indexed: 12/12/2022]
Abstract
The scarcity and limited risk/benefit ratio of painkillers available on the market, in addition to the opioid crisis, warrant reflection on new innovation strategies. The pharmacopoeia of analgesics is based on products that are often old and derived from clinical empiricism, with limited efficacy or spectrum of action, or resulting in an unsatisfactory tolerability profile. Although they are reference analgesics for nociceptive pain, opioids are subject to the same criticism. The use of opium as an analgesic is historical. Morphine was synthesized at the beginning of the 19th century. The efficacy of opioids is limited in certain painful contexts and these drugs can induce potentially serious and fatal adverse effects. The current North American opioid crisis, with an ever-rising number of deaths by opioid overdose, is a tragic illustration of this. It is therefore legitimate to develop research into molecules likely to maintain or increase opioid efficacy while improving their tolerability. Several avenues are being explored including targeting of the mu opioid receptor (MOR) splice variants, developing biased agonists or targeting of other receptors such as heteromers with MOR. Ion channels acting as MOR effectors, are also targeted in order to offer compounds without MOR-dependent adverse effects. Another route is to develop opioid analgesics with peripheral action or limited central nervous system (CNS) access. Finally, endogenous opioids used as drugs or compounds that modify the metabolism of endogenous opioids (Dual ENKephalinase Inhibitors) are being developed. The aim of the present review is to present these various targets/strategies with reference to current indications for opioids, concerns about their widespread use, particularly in chronic non-cancer pains, and ways of limiting the risk of opioid abuse and misuse.
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Affiliation(s)
- Jérôme Busserolles
- Université Clermont Auvergne, INSERM, CHU, NEURO-DOL Pharmacologie Fondamentale et Clinique de la douleur, F-63000 Clermont-Ferrand, France; Institut ANALGESIA, Faculté de Médecine, F-63000 Clermont-Ferrand, France
| | - Stéphane Lolignier
- Université Clermont Auvergne, INSERM, CHU, NEURO-DOL Pharmacologie Fondamentale et Clinique de la douleur, F-63000 Clermont-Ferrand, France; Institut ANALGESIA, Faculté de Médecine, F-63000 Clermont-Ferrand, France
| | - Nicolas Kerckhove
- Université Clermont Auvergne, INSERM, CHU, NEURO-DOL Pharmacologie Fondamentale et Clinique de la douleur, F-63000 Clermont-Ferrand, France; Institut ANALGESIA, Faculté de Médecine, F-63000 Clermont-Ferrand, France; Observatoire Français des Médicaments Antalgiques (OFMA), French monitoring centre for analgesic drugs, CHU, F-63000 Clermont-Ferrand, France
| | - Célian Bertin
- Université Clermont Auvergne, INSERM, CHU, NEURO-DOL Pharmacologie Fondamentale et Clinique de la douleur, F-63000 Clermont-Ferrand, France; Institut ANALGESIA, Faculté de Médecine, F-63000 Clermont-Ferrand, France; Observatoire Français des Médicaments Antalgiques (OFMA), French monitoring centre for analgesic drugs, CHU, F-63000 Clermont-Ferrand, France
| | - Nicolas Authier
- Université Clermont Auvergne, INSERM, CHU, NEURO-DOL Pharmacologie Fondamentale et Clinique de la douleur, F-63000 Clermont-Ferrand, France; Institut ANALGESIA, Faculté de Médecine, F-63000 Clermont-Ferrand, France; Observatoire Français des Médicaments Antalgiques (OFMA), French monitoring centre for analgesic drugs, CHU, F-63000 Clermont-Ferrand, France
| | - Alain Eschalier
- Université Clermont Auvergne, INSERM, CHU, NEURO-DOL Pharmacologie Fondamentale et Clinique de la douleur, F-63000 Clermont-Ferrand, France; Institut ANALGESIA, Faculté de Médecine, F-63000 Clermont-Ferrand, France.
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Xu B, Zhang M, Shi X, Zhang R, Chen D, Chen Y, Wang Z, Qiu Y, Zhang T, Xu K, Zhang X, Liedtke W, Wang R, Fang Q. The multifunctional peptide DN-9 produced peripherally acting antinociception in inflammatory and neuropathic pain via μ- and κ-opioid receptors. Br J Pharmacol 2019; 177:93-109. [PMID: 31444977 DOI: 10.1111/bph.14848] [Citation(s) in RCA: 25] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/04/2019] [Revised: 08/05/2019] [Accepted: 08/20/2019] [Indexed: 12/22/2022] Open
Abstract
BACKGROUND AND PURPOSE Considerable effort has recently been directed at developing multifunctional opioid drugs to minimize the unwanted side effects of opioid analgesics. We have developed a novel multifunctional opioid agonist, DN-9. Here, we studied the analgesic profiles and related side effects of peripheral DN-9 in various pain models. EXPERIMENTAL APPROACH Antinociceptive effects of DN-9 were assessed in nociceptive, inflammatory, and neuropathic pain. Whole-cell patch-clamp and calcium imaging assays were used to evaluate the inhibitory effects of DN-9 to calcium current and high-K+ -induced intracellular calcium ([Ca2+ ]i ) on dorsal root ganglion (DRG) neurons respectively. Side effects of DN-9 were evaluated in antinociceptive tolerance, abuse, gastrointestinal transit, and rotarod tests. KEY RESULTS DN-9, given subcutaneously, dose-dependently produced antinociception via peripheral opioid receptors in different pain models without sex difference. In addition, DN-9 exhibited more potent ability than morphine to inhibit calcium current and high-K+ -induced [Ca2+ ]i in DRG neurons. Repeated treatment with DN-9 produced equivalent antinociception for 8 days in multiple pain models, and DN-9 also maintained potent analgesia in morphine-tolerant mice. Furthermore, chronic DN-9 administration had no apparent effect on the microglial activation of spinal cord. After subcutaneous injection, DN-9 exhibited less abuse potential than morphine, as was gastroparesis and effects on motor coordination. CONCLUSIONS AND IMPLICATIONS DN-9 produces potent analgesia with minimal side effects, which strengthen the candidacy of peripherally acting opioids with multifunctional agonistic properties to enter human studies to alleviate the current highly problematic misuse of classic opioids on a large scale.
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Affiliation(s)
- Biao Xu
- Key Laboratory of Preclinical Study for New Drugs of Gansu Province, and Institute of Physiology, School of Basic Medical Sciences, Lanzhou University, Lanzhou, China
| | - Mengna Zhang
- Key Laboratory of Preclinical Study for New Drugs of Gansu Province, and Institute of Physiology, School of Basic Medical Sciences, Lanzhou University, Lanzhou, China
| | - Xuerui Shi
- Key Laboratory of Preclinical Study for New Drugs of Gansu Province, and Institute of Physiology, School of Basic Medical Sciences, Lanzhou University, Lanzhou, China
| | - Run Zhang
- Key Laboratory of Preclinical Study for New Drugs of Gansu Province, and Institute of Physiology, School of Basic Medical Sciences, Lanzhou University, Lanzhou, China
| | - Dan Chen
- Key Laboratory of Preclinical Study for New Drugs of Gansu Province, and Institute of Physiology, School of Basic Medical Sciences, Lanzhou University, Lanzhou, China
| | - Yong Chen
- Department of Neurology, Duke University School of Medicine, Durham, North Carolina
| | - Zilong Wang
- Key Laboratory of Preclinical Study for New Drugs of Gansu Province, and Institute of Physiology, School of Basic Medical Sciences, Lanzhou University, Lanzhou, China
| | - Yu Qiu
- Department of Pharmacology and Chemical Biology, Institute of Medical Sciences, Shanghai Jiao Tong University School of Medicine, Shanghai, China
| | - Ting Zhang
- Key Laboratory of Preclinical Study for New Drugs of Gansu Province, and Institute of Physiology, School of Basic Medical Sciences, Lanzhou University, Lanzhou, China
| | - Kangtai Xu
- Key Laboratory of Preclinical Study for New Drugs of Gansu Province, and Institute of Physiology, School of Basic Medical Sciences, Lanzhou University, Lanzhou, China
| | - Xiaoyu Zhang
- Key Laboratory of Preclinical Study for New Drugs of Gansu Province, and Institute of Physiology, School of Basic Medical Sciences, Lanzhou University, Lanzhou, China
| | - Wolfgang Liedtke
- Department of Neurology, Duke University School of Medicine, Durham, North Carolina
| | - Rui Wang
- Key Laboratory of Preclinical Study for New Drugs of Gansu Province, and Institute of Physiology, School of Basic Medical Sciences, Lanzhou University, Lanzhou, China
| | - Quan Fang
- Key Laboratory of Preclinical Study for New Drugs of Gansu Province, and Institute of Physiology, School of Basic Medical Sciences, Lanzhou University, Lanzhou, China
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Chakrabarti S, Liu NJ, Gintzler AR. Phosphorylation of unique C-terminal sites of the mu-opioid receptor variants 1B2 and 1C1 influences their Gs association following chronic morphine. J Neurochem 2019; 152:449-467. [PMID: 31479519 DOI: 10.1111/jnc.14863] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/14/2019] [Revised: 03/14/2019] [Accepted: 08/11/2019] [Indexed: 11/27/2022]
Abstract
We recently demonstrated in rat spinal cord that a regimen of escalating doses of systemic morphine, analogous to regimens used clinically for chronic pain management, selectively up-regulates the mu-opioid receptor (MOR) splice variants MOR-1B2 and MOR-1C1 mRNA and functional protein. This study investigated the potential relevance of up-regulating MOR-1B2 and MOR-1C1 to the ability of chronic morphine to shift MOR signaling from predominantly Gi /Go inhibitory to Gs stimulatory. Specifically, we tested the hypotheses that chronic morphine induces phosphorylation of carboxyl terminal sites unique to MOR-1B2 and MOR-1C1, and that this phosphorylation is causally related to augmented association of these variants with Gs α. Hypotheses were validated by (i) abolition of the chronic morphine-induced increment in MOR-1C1 and MOR-1B2 association with Gs α by inhibitors of protein kinase A and Casein kinase 2, respectively; (ii) failure of chronic morphine to augment MOR variant Gs α interactions in Chinese hamster ovary cells transiently transfected with either rat MOR-1C1 or MOR-1B2 in which targeted protein kinase A and Casein kinase 2 serine phosphorylation sites, respectively, were mutated to alanine; (iii) abrogation of chronic morphine-induced augmented MOR Gs α association in spinal cord of male rats following intrathecal administration of dicer substrate small interfering RNAs targeting MOR-1B2/MOR-1C1 mRNA. The ability of chronic morphine to not only up-regulate-specific MOR variants but also their carboxyl terminal phosphorylation and consequent augmented association with Gs α may represent a novel component of opioid tolerance mechanisms, suggesting novel potential targets for tolerance abatement.
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Affiliation(s)
- Sumita Chakrabarti
- Department of Obstetrics and Gynecology, State University of New York, Downstate Medical Center, Brooklyn, New York, USA
| | - Nai-Jiang Liu
- Department of Obstetrics and Gynecology, State University of New York, Downstate Medical Center, Brooklyn, New York, USA
| | - Alan R Gintzler
- Department of Obstetrics and Gynecology, State University of New York, Downstate Medical Center, Brooklyn, New York, USA
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Arttamangkul S, Plazek A, Platt EJ, Jin H, Murray TF, Birdsong WT, Rice KC, Farrens DL, Williams JT. Visualizing endogenous opioid receptors in living neurons using ligand-directed chemistry. eLife 2019; 8:49319. [PMID: 31589142 PMCID: PMC6809603 DOI: 10.7554/elife.49319] [Citation(s) in RCA: 27] [Impact Index Per Article: 5.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/04/2019] [Accepted: 10/06/2019] [Indexed: 12/11/2022] Open
Abstract
Identifying neurons that have functional opioid receptors is fundamental for the understanding of the cellular, synaptic and systems actions of opioids. Current techniques are limited to post hoc analyses of fixed tissues. Here we developed a fluorescent probe, naltrexamine-acylimidazole (NAI), to label opioid receptors based on a chemical approach termed ‘traceless affinity labeling’. In this approach, a high affinity antagonist naltrexamine is used as the guide molecule for a transferring reaction of acylimidazole at the receptor. This reaction generates a fluorescent dye covalently linked to the receptor while naltrexamine is liberated and leaves the binding site. The labeling induced by this reagent allowed visualization of opioid-sensitive neurons in rat and mouse brains without loss of function of the fluorescently labeled receptors. The ability to locate endogenous receptors in living tissues will aid considerably in establishing the distribution and physiological role of opioid receptors in the CNS of wild type animals.
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Affiliation(s)
- Seksiri Arttamangkul
- The Vollum Institute, Oregon Health & Science University, Portland, United States
| | - Andrew Plazek
- Medicinal Chemistry Core, Oregon Health & Science University, Portland, United States
| | - Emily J Platt
- Department of Biochemistry and Molecular Biology, School of Medicine, Oregon Health & Science University, Portland, United States
| | - Haihong Jin
- Medicinal Chemistry Core, Oregon Health & Science University, Portland, United States
| | - Thomas F Murray
- Department of Pharmacology, School of Medicine, Creighton University, Omaha, United States
| | - William T Birdsong
- The Vollum Institute, Oregon Health & Science University, Portland, United States
| | - Kenner C Rice
- Drug Design and Synthesis Section, Intramural Research Program, NIDA and NIAAA, Bethesda, United States
| | - David L Farrens
- Department of Biochemistry and Molecular Biology, School of Medicine, Oregon Health & Science University, Portland, United States
| | - John T Williams
- The Vollum Institute, Oregon Health & Science University, Portland, United States
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Chao PK, Chang HF, Chang WT, Yeh TK, Ou LC, Chuang JY, Tsu-An Hsu J, Tao PL, Loh HH, Shih C, Ueng SH, Yeh SH. BPR1M97, a dual mu opioid receptor/nociceptin-orphanin FQ peptide receptor agonist, produces potent antinociceptive effects with safer properties than morphine. Neuropharmacology 2019; 166:107678. [PMID: 31278929 DOI: 10.1016/j.neuropharm.2019.107678] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/13/2018] [Revised: 05/21/2019] [Accepted: 06/18/2019] [Indexed: 01/14/2023]
Abstract
There is unmet need to design an analgesic with fewer side effects for severe pain management. Although traditional opioids are the most effective painkillers, they are accompanied by severe adverse responses, such as respiratory depression, constipation symptoms, tolerance, withdrawal, and addiction. We indicated BPR1M97 as a dual mu opioid receptor (MOP)/nociceptin-orphanin FQ peptide (NOP) receptor full agonist and investigated the pharmacology of BPR1M97 in multiple animal models. In vitro studies on BPR1M97 were assessed using cyclic-adenosine monophosphate production, β-arrestin, internalization, and membrane potential assays. In vivo studies were characterized using the tail-flick, tail-clip, lung functional, heart functional, acetone drop, von Frey hair, charcoal meal, glass bead, locomotor activity, conditioned place preference (CPP) and naloxone precipitation tests. BPR1M97 elicited full agonist properties for all cell-based assays tested in MOP-expressing cells. However, it acted as a G protein-biased agonist for NOP. BPR1M97 initiated faster antinociceptive effects at 10 min after subcutaneous injection and elicited better analgesia in cancer-induced pain than morphine. Unlike morphine, BPR1M97 caused less respiratory, cardiovascular, and gastrointestinal dysfunction. In addition, BPR1M97 decreased global activity and induced less withdrawal jumping precipitated by naloxone. Thus, BPR1M97 could serve as a novel small molecule dual receptor agonist for antinociception with fewer side effects than morphine. This article is part of the Special Issue entitled 'New Vistas in Opioid Pharmacology'.
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Affiliation(s)
- Po-Kuan Chao
- Institute of Biotechnology and Pharmaceutical Research, National Health Research Institutes, Miaoli County, 35053, Taiwan
| | - Hsiao-Fu Chang
- Institute of Biotechnology and Pharmaceutical Research, National Health Research Institutes, Miaoli County, 35053, Taiwan
| | - Wan-Ting Chang
- Institute of Biotechnology and Pharmaceutical Research, National Health Research Institutes, Miaoli County, 35053, Taiwan
| | - Teng-Kuang Yeh
- Institute of Biotechnology and Pharmaceutical Research, National Health Research Institutes, Miaoli County, 35053, Taiwan
| | - Li-Chin Ou
- Institute of Biotechnology and Pharmaceutical Research, National Health Research Institutes, Miaoli County, 35053, Taiwan
| | - Jian-Ying Chuang
- The PhD Program for Neural Regenerative Medicine, Taipei Medical University, Taipei, 110, Taiwan
| | - John Tsu-An Hsu
- Institute of Biotechnology and Pharmaceutical Research, National Health Research Institutes, Miaoli County, 35053, Taiwan
| | - Pao-Luh Tao
- Center for Neuropsychiatric Research, National Heath Research Institutes, Zhunan, Miaoli County, 35053, Taiwan
| | - Horace H Loh
- Department of Pharmacology, University of Minnesota Medical School, Minneapolis, MN, 55455-0217, USA
| | - Chuan Shih
- Institute of Biotechnology and Pharmaceutical Research, National Health Research Institutes, Miaoli County, 35053, Taiwan
| | - Shau-Hua Ueng
- Institute of Biotechnology and Pharmaceutical Research, National Health Research Institutes, Miaoli County, 35053, Taiwan; School of Pharmacy, National Cheng Kung University, Tainan, Taiwan, ROC.
| | - Shiu-Hwa Yeh
- Institute of Biotechnology and Pharmaceutical Research, National Health Research Institutes, Miaoli County, 35053, Taiwan; The PhD Program for Neural Regenerative Medicine, Taipei Medical University, Taipei, 110, Taiwan.
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Synaptic Regulation by OPRM1 Variants in Reward Neurocircuitry. J Neurosci 2019; 39:5685-5696. [PMID: 31109961 DOI: 10.1523/jneurosci.2317-18.2019] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/08/2018] [Revised: 05/03/2019] [Accepted: 05/03/2019] [Indexed: 12/12/2022] Open
Abstract
Mu-opioid receptors (MORs) are the primary site of action of opioid drugs, both licit and illicit. Susceptibility to opioid addiction is associated with variants in the gene encoding the MOR, OPRM1 Varying with ethnicity, ∼25% of humans carry a single nucleotide polymorphism (SNP) in OPRM1 (A118G). This SNP produces a nonsynonymous amino acid substitution, replacing asparagine (N40) with aspartate (D40), and has been linked with an increased risk for drug addiction. While a murine model of human OPRM1 A118G (A112G in mouse) recapitulates most of the phenotypes reported in humans, the neuronal mechanisms underlying these phenotypes remain elusive. Here, we investigated the impact of A118G on opioid regulation of synaptic transmission in mesolimbic VTA dopaminergic neurons. Using electrophysiology, we showed that both inhibitory and excitatory inputs to VTA dopaminergic neurons projecting to the NAc medial shell were suppressed by the MOR agonists DAMGO and morphine, which caused a shift in the excitatory/inhibitory balance and an increased action potential firing rate. Mice carrying the 112G/G allele exhibited lower sensitivity to DAMGO and morphine compared with major allele carriers (112A/A). Paradoxically, DAMGO produced facilitatory effects on mEPSCs, which were mediated by presynaptic GABAB receptors. However, this was only prominent in homozygous major allele carriers, which could explain a stronger shift in action potential firing in 112A/A mice. This study provides a better understanding on the neurobiological mechanisms that may underlie risk of addiction development in carriers of the A118G SNP in OPRM1 SIGNIFICANCE STATEMENT The pandemic of opioid drug abuse is associated with many socioeconomic burdens. The primary brain target of opioid drugs is the μ-opioid receptor (MOR), encoded by the OPRM1 gene, which is highly polymorphic in humans. Using a mouse model of the human OPRM1 A118G single nucleotide polymorphism (SNP) (A112G in mice), we demonstrated that MOR and GABAB signaling coordinate in regulating mesolimbic dopamine neuronal firing via presynaptic regulation. The A118G SNP affects MOR-mediated suppression of GABA and glutamate release, showing weaker efficacy of synaptic regulation by MORs. These results may shed light on whether MOR SNPs need to be considered for devising effective therapeutic interventions.
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Lin SY, Kuo YH, Tien YW, Ke YY, Chang WT, Chang HF, Ou LC, Law PY, Xi JH, Tao PL, Loh HH, Chao YS, Shih C, Chen CT, Yeh SH, Ueng SH. The in vivo antinociceptive and μ-opioid receptor activating effects of the combination of N-phenyl-2',4'-dimethyl-4,5'-bi-1,3-thiazol-2-amines and naloxone. Eur J Med Chem 2019; 167:312-323. [PMID: 30776693 DOI: 10.1016/j.ejmech.2019.01.063] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/26/2018] [Revised: 01/17/2019] [Accepted: 01/26/2019] [Indexed: 12/19/2022]
Abstract
Morphine is widely used for the treatment of severe pain. This analgesic effect is mediated principally by the activation of μ-opioid receptors (MOR). However, prolonged activation of MOR also results in tolerance, dependence, addiction, constipation, nausea, sedation, and respiratory depression. To address this problem, we sought alternative ways to activate MOR - either by use of novel ligands, or via a novel activation mechanism. To this end, a series of compounds were screened using a sensitive CHO-K1/MOR/Gα15 cell-based FLIPR® calcium high-throughput screening (HTS) assay, and the bithiazole compound 5a was identified as being able activate MOR in combination with naloxone. Structural modifications of 5a resulted in the discovery of lead compound 5j, which could effectively activate MOR in combination with the MOR antagonist naloxone or naltrexone. In vivo, naloxone in combination with 100 mg/kg of compound 5j elicited antinociception in a mouse tail-flick model with an ED50 of 17.5 ± 4 mg/kg. These results strongly suggest that the mechanism by which the 5j/naloxone combination activates MOR is worthy of further study, as its discovery has the potential to yield an entirely novel class of analgesics.
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Affiliation(s)
- Shu-Yu Lin
- Institute of Biotechnology and Pharmaceutical Research, National Health Research Institutes, Miaoli County, 35053, Taiwan, ROC
| | - Yu-Hsien Kuo
- Institute of Biotechnology and Pharmaceutical Research, National Health Research Institutes, Miaoli County, 35053, Taiwan, ROC
| | - Ya-Wen Tien
- Institute of Biotechnology and Pharmaceutical Research, National Health Research Institutes, Miaoli County, 35053, Taiwan, ROC
| | - Yi-Yu Ke
- Institute of Biotechnology and Pharmaceutical Research, National Health Research Institutes, Miaoli County, 35053, Taiwan, ROC
| | - Wan-Ting Chang
- Institute of Biotechnology and Pharmaceutical Research, National Health Research Institutes, Miaoli County, 35053, Taiwan, ROC
| | - Hsiao-Fu Chang
- Institute of Biotechnology and Pharmaceutical Research, National Health Research Institutes, Miaoli County, 35053, Taiwan, ROC
| | - Li-Chin Ou
- Institute of Biotechnology and Pharmaceutical Research, National Health Research Institutes, Miaoli County, 35053, Taiwan, ROC
| | - Ping-Yee Law
- Department of Pharmacology, University of Minnesota, Medical School, Minneapolis, MN, 55455, USA
| | - Jing-Hua Xi
- Department of Pharmacology, University of Minnesota, Medical School, Minneapolis, MN, 55455, USA
| | - Pao-Luh Tao
- Center for Neuropsychiatric Research, National Health Research Institutes, Zhunan, Miaoli County, Taiwan, ROC
| | - Horace H Loh
- Department of Pharmacology, University of Minnesota, Medical School, Minneapolis, MN, 55455, USA
| | - Yu-Sheng Chao
- Institute of Biotechnology and Pharmaceutical Research, National Health Research Institutes, Miaoli County, 35053, Taiwan, ROC
| | - Chuan Shih
- Institute of Biotechnology and Pharmaceutical Research, National Health Research Institutes, Miaoli County, 35053, Taiwan, ROC
| | - Chiung-Tong Chen
- Institute of Biotechnology and Pharmaceutical Research, National Health Research Institutes, Miaoli County, 35053, Taiwan, ROC
| | - Shiu-Hwa Yeh
- Institute of Biotechnology and Pharmaceutical Research, National Health Research Institutes, Miaoli County, 35053, Taiwan, ROC; The PhD Program for Neural Regenerative Medicine, Taipei Medical University, Taipei, 110, Taiwan, ROC.
| | - Shau-Hua Ueng
- Institute of Biotechnology and Pharmaceutical Research, National Health Research Institutes, Miaoli County, 35053, Taiwan, ROC; School of Pharmacy, National Cheng Kung University, Tainan, Taiwan, ROC.
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Pasternak GW, Childers SR, Pan YX. Emerging Insights into Mu Opioid Pharmacology. Handb Exp Pharmacol 2019; 258:89-125. [PMID: 31598835 DOI: 10.1007/164_2019_270] [Citation(s) in RCA: 15] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/30/2022]
Abstract
Opioid analgesics, most of which act through mu opioid receptors, have long represented valuable therapeutic agents to treat severe pain. Concerted drug development efforts for over a 100 years have resulted in a large variety of opioid analgesics used in the clinic, but all of them continue to exhibit the side effects, especially respiratory depression, that have long plagued the use of morphine. The recent explosion in fatalities resulting from overdose of prescription and synthetic opioids has dramatically increased the need for safer analgesics, but recent developments in mu receptor research have provided new strategies to develop such drugs. This chapter reviews recent advances in developing novel opioid analgesics from an understanding of mu receptor structure and function. This includes a summary of the mechanism of agonist binding deduced from the crystal structure of mu receptors. It will also highlight the development of novel agonist mechanisms, including biased agonists, bivalent ligands, and allosteric modulators of mu receptor function, and describe how receptor phosphorylation modulates these pathways. Finally, it will summarize research on the alternative pre-mRNA splicing mechanisms that produces a multiplicity of mu receptor isoforms. Many of these isoforms exhibit different pharmacological specificities and brain circuitry localization, thus providing an opportunity to develop novel drugs with increased therapeutic windows.
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Affiliation(s)
- Gavril W Pasternak
- Department of Neurology and Molecular Pharmacology Program, Memorial Sloan Kettering Cancer Center, New York, NY, USA
| | - Steven R Childers
- Department of Physiology/Pharmacology, Wake Forest School of Medicine, Winston-Salem, NC, USA.
| | - Ying-Xian Pan
- Department of Neurology and Molecular Pharmacology Program, Memorial Sloan Kettering Cancer Center, New York, NY, USA.
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Lu Z, Xu J, Xu M, Rossi GC, Majumdar S, Pasternak GW, Pan YX. Truncated μ-Opioid Receptors With 6 Transmembrane Domains Are Essential for Opioid Analgesia. Anesth Analg 2018; 126:1050-1057. [PMID: 28991118 DOI: 10.1213/ane.0000000000002538] [Citation(s) in RCA: 21] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/19/2022]
Abstract
BACKGROUND Most clinical opioids act through μ-opioid receptors. They effectively relieve pain but are limited by side effects, such as constipation, respiratory depression, dependence, and addiction. Many efforts have been made toward developing potent analgesics that lack side effects. Three-iodobenzoyl-6β-naltrexamide (IBNtxA) is a novel class of opioid active against thermal, inflammatory, and neuropathic pain, without respiratory depression, physical dependence, and reward behavior. The μ-opioid receptor (OPRM1) gene undergoes extensive alternative precursor messenger ribonucleic acid splicing, generating multiple splice variants that are conserved from rodents to humans. One type of variant is the exon 11 (E11)-associated truncated variant containing 6 transmembrane domains (6TM variant). There are 5 6TM variants in the mouse OPRM1 gene, including mMOR-1G, mMOR-1M, mMOR-1N, mMOR-1K, and mMOR-1L. Gene-targeting mouse models selectively removing 6TM variants in E11 knockout (KO) mice eliminated IBNtxA analgesia without affecting morphine analgesia. Conversely, morphine analgesia is lost in an exon 1 (E1) KO mouse that lacks all 7 transmembrane (7TM) variants but retains 6TM variant expression, while IBNtxA analgesia remains intact. Elimination of both E1 and E11 in an E1/E11 double KO mice abolishes both morphine and IBNtxA analgesia. Reconstituting expression of the 6TM variant mMOR-1G in E1/E11 KO mice through lentiviral expression rescued IBNtxA but not morphine analgesia. The aim of this study was to investigate the effect of lentiviral expression of the other 6TM variants in E1/E11 KO mice on IBNtxA analgesia. METHODS Lentiviruses expressing 6TM variants were packaged in HEK293T cells, concentrated by ultracentrifugation, and intrathecally administered 3 times. Opioid analgesia was determined using a radiant-heat tail-flick assay. Expression of lentiviral 6TM variant messenger ribonucleic acids was examined by polymerase chain reaction (PCR) or quantitative PCR. RESULTS All the 6TM variants restored IBNtxA analgesia in the E1/E11 KO mouse, while morphine remained inactive. Expression of lentiviral 6TM variants was confirmed by PCR or quantitative PCR. IBNtxA median effective dose values determined from cumulative dose-response studies in the rescued mice were indistinguishable from wild-type animals. IBNtxA analgesia was maintained for up to 33 weeks in the rescue mice and was readily antagonized by the opioid antagonist levallorphan. CONCLUSIONS Our study demonstrated the pharmacological relevance of mouse 6TM variants in IBNtxA analgesia and established that a common functional core of the receptors corresponding to the transmembrane domains encoded by exons 2 and 3 is sufficient for activity. Thus, 6TM variants offer potential therapeutic targets for a distinct class of analgesics that are effective against broad-spectrum pain models without many side effects associated with traditional opioids.
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Affiliation(s)
- Zhigang Lu
- From the The Affiliated Hospital of Nanjing University of Chinese Medicine, First College of Clinical Medicine.,Key Laboratory of Acupuncture and Medicine Research of Ministry of Education Nanjing University of Chinese Medicine, Nanjing, China
| | - Jin Xu
- Department of Neurology and the Molecular Pharmacology Program, Memorial Sloan-Kettering Cancer Center, New York, New York
| | - Mingming Xu
- Department of Neurology and the Molecular Pharmacology Program, Memorial Sloan-Kettering Cancer Center, New York, New York
| | - Grace C Rossi
- Department of Psychology, Long Island University, Post Campus, Brookville, New York
| | - Susruta Majumdar
- Department of Neurology and the Molecular Pharmacology Program, Memorial Sloan-Kettering Cancer Center, New York, New York
| | - Gavril W Pasternak
- Department of Neurology and the Molecular Pharmacology Program, Memorial Sloan-Kettering Cancer Center, New York, New York
| | - Ying-Xian Pan
- Department of Neurology and the Molecular Pharmacology Program, Memorial Sloan-Kettering Cancer Center, New York, New York
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37
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Sader S, Anant K, Wu C. To probe interaction of morphine and IBNtxA with 7TM and 6TM variants of the human μ-opioid receptor using all-atom molecular dynamics simulations with an explicit membrane. Phys Chem Chem Phys 2018; 20:1724-1741. [PMID: 29265141 DOI: 10.1039/c7cp06745c] [Citation(s) in RCA: 12] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/20/2022]
Abstract
IBNtxA, a morphine derivative, is 10-fold more potent and has a better safety profile than morphine. Animal studies indicate that the analgesic effect of IBNtxA appears to be mediated by the activation of truncated splice variants (6TM) of the Mu opioid receptor (MOR-1) where transmembrane helix 1 (TM1) is removed. Interestingly, morphine is unable to activate 6TM variants. To date, a high resolution structure of 6TM variants is missing, and the interaction of 6TM variants with IBNtxA and morphine remains elusive. In this study we used homology modeling, docking and molecular dynamics (MD) simulations to study a representative 6TM variant (G1) and a full-length 7TM variant of human MOR-1 in complex with IBNtxA and morphine respectively. The structural models of human G1 and 7TM were obtained by homology modeling using the X-ray solved crystal structure of the active mouse 7TM bound to an agonist BU72 (PDB id: ) as the template. Our 6000 ns MD data show that either TM1 truncation (i.e. from 7TM to 6TM) or ligand modification (i.e. from morphine to IBNtxA) alone causes the loss of key morphine-7TM interactions that are well-known to be required for MOR-1 activation. Receptor disruptions are mainly located at TMs 2, 3, 6 and 7 in comparison with the active crystal complex. However, when both perturbations occur in the 6TM-IBNtxA complex, the key ligand-receptor interactions and the receptor conformation are recovered to resemble those in the active 7TM-morphine complex. Our molecular switch analysis further explains well why morphine is not able to activate 6TM variants. The close resemblance between 6TM-IBTtxA and 7TM in complex with PZM21, a G-protein biased 7TM agonist, suggests the possible biased agonism of IBNtxA on G1, which is consistent with its reduced side effects.
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Affiliation(s)
- Safaa Sader
- College of Science and Mathematics, Rowan University, Glassboro, NJ 08028, USA.
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38
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Maldonado R, Baños JE, Cabañero D. Usefulness of knockout mice to clarify the role of the opioid system in chronic pain. Br J Pharmacol 2018; 175:2791-2808. [PMID: 29124744 DOI: 10.1111/bph.14088] [Citation(s) in RCA: 21] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/10/2017] [Revised: 10/13/2017] [Accepted: 10/17/2017] [Indexed: 12/29/2022] Open
Abstract
Several lines of knockout mice deficient in the genes encoding each component of the endogenous opioid system have been used for decades to clarify the specific role of the different opioid receptors and peptide precursors in many physiopathological conditions. The use of these genetically modified mice has improved our knowledge of the specific involvement of each endogenous opioid component in nociceptive transmission during acute and chronic pain conditions. The present review summarizes the recent advances obtained using these genetic tools in understanding the role of the opioid system in the pathophysiological mechanisms underlying chronic pain. Behavioural data obtained in these chronic pain models are discussed considering the peculiarities of the behavioural phenotype of each line of knockout mice. These studies have identified the crucial role of specific components of the opioid system in different manifestations of chronic pain and have also opened new possible therapeutic approaches, such as the development of opioid compounds simultaneously targeting several opioid receptors. However, several questions still remain open and require further experimental effort to be clarified. The novel genetic tools now available to manipulate specific neuronal populations and precise genome editing in mice will facilitate in a near future the elucidation of the role of each component of the endogenous opioid system in chronic pain. LINKED ARTICLES This article is part of a themed section on Emerging Areas of Opioid Pharmacology. To view the other articles in this section visit http://onlinelibrary.wiley.com/doi/10.1111/bph.v175.14/issuetoc.
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Affiliation(s)
- Rafael Maldonado
- Laboratory of Neuropharmacology, Department of Experimental and Health Sciences, Universitat Pompeu Fabra, Barcelona, Spain.,IMIM (Hospital del Mar Medical Research Institute), Barcelona, Spain
| | - Josep Eladi Baños
- Laboratory of Neuropharmacology, Department of Experimental and Health Sciences, Universitat Pompeu Fabra, Barcelona, Spain.,IMIM (Hospital del Mar Medical Research Institute), Barcelona, Spain
| | - David Cabañero
- Laboratory of Neuropharmacology, Department of Experimental and Health Sciences, Universitat Pompeu Fabra, Barcelona, Spain
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39
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Pasternak GW. Mu Opioid Pharmacology: 40 Years to the Promised Land. ADVANCES IN PHARMACOLOGY 2018; 82:261-291. [DOI: 10.1016/bs.apha.2017.09.006] [Citation(s) in RCA: 36] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 02/07/2023]
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40
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The Behavioral Effects of the Antidepressant Tianeptine Require the Mu-Opioid Receptor. Neuropsychopharmacology 2017; 42:2052-2063. [PMID: 28303899 PMCID: PMC5561344 DOI: 10.1038/npp.2017.60] [Citation(s) in RCA: 70] [Impact Index Per Article: 10.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 04/24/2016] [Revised: 02/28/2017] [Accepted: 03/02/2017] [Indexed: 12/12/2022]
Abstract
Depression is a debilitating chronic illness that affects around 350 million people worldwide. Current treatments, such as selective serotonin reuptake inhibitors, are not ideal because only a fraction of patients achieve remission. Tianeptine is an effective antidepressant with a previously unknown mechanism of action. We recently reported that tianeptine is a full agonist at the mu opioid receptor (MOR). Here we demonstrate that the acute and chronic antidepressant-like behavioral effects of tianeptine in mice require MOR. Interestingly, while tianeptine also produces many opiate-like behavioral effects such as analgesia and reward, it does not lead to tolerance or withdrawal. Furthermore, the primary metabolite of tianeptine (MC5), which has a longer half-life, mimics the behavioral effects of tianeptine in a MOR-dependent fashion. These results point to the possibility that MOR and its downstream signaling cascades may be novel targets for antidepressant drug development.
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41
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Genetic dissociation of morphine analgesia from hyperalgesia in mice. Psychopharmacology (Berl) 2017; 234:1891-1900. [PMID: 28343361 PMCID: PMC5520541 DOI: 10.1007/s00213-017-4600-2] [Citation(s) in RCA: 17] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 01/06/2017] [Accepted: 03/10/2017] [Indexed: 01/10/2023]
Abstract
RATIONALE Morphine is the prototypic mu opioid, producing its analgesic actions through traditional 7 transmembrane domain (7TM) G-protein-coupled receptors generated by the mu opioid receptor gene (Oprm1). However, the Oprm1 gene undergoes extensive alternative splicing to yield three structurally distinct sets of splice variants. In addition to the full-length 7TM receptors, it produces a set of truncated variants comprised of only 6 transmembrane domains (6TM). OBJECTIVES This study explored the relative contributions of 7TM and 6TM variants in a range of morphine actions. METHODS Groups of male and mixed-gender wild-type and exon 11 Oprm1 knockout mice were examined in a series of behavioral assays measuring analgesia, hyperalgesia, respiration, and reward in conditioned place preference assays. RESULTS Loss of the 6TM variants in an exon 11 knockout (E11 KO) mouse did not affect morphine analgesia, reward, or respiratory depression. However, E11 KO mice lacking 6TM variants failed to show morphine-induced hyperalgesia, developed tolerance more slowly than wild-type mice, and did not display hyperlocomotion. CONCLUSIONS Together, our findings confirm the established role of 7TM mu receptor variants in morphine analgesia, reward, and respiratory depression, but reveal an unexpected obligatory role for 6TM variants in morphine-induced hyperalgesia and a modulatory role in morphine tolerance and dependence.
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42
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Xu J, Lu Z, Narayan A, Le Rouzic VP, Xu M, Hunkele A, Brown TG, Hoefer WF, Rossi GC, Rice RC, Martínez-Rivera A, Rajadhyaksha AM, Cartegni L, Bassoni DL, Pasternak GW, Pan YX. Alternatively spliced mu opioid receptor C termini impact the diverse actions of morphine. J Clin Invest 2017; 127:1561-1573. [PMID: 28319053 DOI: 10.1172/jci88760] [Citation(s) in RCA: 51] [Impact Index Per Article: 7.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/23/2016] [Accepted: 01/12/2017] [Indexed: 12/22/2022] Open
Abstract
Extensive 3' alternative splicing of the mu opioid receptor gene OPRM1 creates multiple C-terminal splice variants. However, their behavioral relevance remains unknown. The present study generated 3 mutant mouse models with truncated C termini in 2 different mouse strains, C57BL/6J (B6) and 129/SvEv (129). One mouse truncated all C termini downstream of Oprm1 exon 3 (mE3M mice), while the other two selectively truncated C-terminal tails encoded by either exon 4 (mE4M mice) or exon 7 (mE7M mice). Studies of these mice revealed divergent roles for the C termini in morphine-induced behaviors, highlighting the importance of C-terminal variants in complex morphine actions. In mE7M-B6 mice, the exon 7-associated truncation diminished morphine tolerance and reward without altering physical dependence, whereas the exon 4-associated truncation in mE4M-B6 mice facilitated morphine tolerance and reduced morphine dependence without affecting morphine reward. mE7M-B6 mutant mice lost morphine-induced receptor desensitization in the brain stem and hypothalamus, consistent with exon 7 involvement in morphine tolerance. In cell-based studies, exon 7-associated variants shifted the bias of several mu opioids toward β-arrestin 2 over G protein activation compared with the exon 4-associated variant, suggesting an interaction of exon 7-associated C-terminal tails with β-arrestin 2 in morphine-induced desensitization and tolerance. Together, the differential effects of C-terminal truncation illustrate the pharmacological importance of OPRM1 3' alternative splicing.
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43
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Schattauer SS, Kuhar JR, Song A, Chavkin C. Nalfurafine is a G-protein biased agonist having significantly greater bias at the human than rodent form of the kappa opioid receptor. Cell Signal 2017; 32:59-65. [PMID: 28088389 DOI: 10.1016/j.cellsig.2017.01.016] [Citation(s) in RCA: 85] [Impact Index Per Article: 12.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/28/2016] [Revised: 12/04/2016] [Accepted: 01/09/2017] [Indexed: 11/27/2022]
Abstract
Nalfurafine is a moderately selective kappa opioid receptor (KOR) analgesic with low incidence of dysphoric side effects in clinical development for the treatment of uremic pruritis. The basis for its reduced dysphoric effect compared to other KOR agonists is not clear, but prior studies suggest that the aversive properties of KOR agonists require p38α MAPK activation through an arrestin-dependent mechanism. To determine whether nalfurafine is a functionally selective KOR agonist, we measured its potency to activate the G protein-dependent early phase of Extracellular Signal-Regulated Kinase (ERK1/2) phosphorylation and the arrestin-dependent late phase of p38 MAPK signaling. Nalfurafine was approximately 250 fold more potent for ERK1/2 activation as compared to p38 MAPK activation in human KOR (hKOR) expressing HEK293 cells, and approximately 20 fold more potent for ERK1/2 activation than p38 activation in rodent KOR (rKOR) expressing HEK293 cells. The 10-fold greater G-bias at the hKOR than rKOR was unexpected, however the G protein biased effect of nalfurafine is consistent with its reduced dysphoric effects in human and rodent models. Although nalfurafine is reported to have low receptor selectivity in radioligand binding assays, its antinociceptive effect was blocked by the selective KOR antagonist norbinaltorphimine. Nalfurafine pretreatment also resulted in a KOR-dependent and mu opioid receptor-independent reduction in scratching induced by 5'-GNTI. These findings suggest that nalfurafine is a functionally selective KOR agonist and that KOR agonists able to selectively activate G protein signaling without activating p38α MAPK may have therapeutic potential as non-dysphoric antipruritic analgesics.
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Affiliation(s)
- Selena S Schattauer
- Department of Pharmacology, University of Washington, Seattle, WA 98195-7280, United States
| | - Jamie R Kuhar
- Department of Pharmacology, University of Washington, Seattle, WA 98195-7280, United States
| | - Allisa Song
- Department of Pharmacology, University of Washington, Seattle, WA 98195-7280, United States
| | - Charles Chavkin
- Department of Pharmacology, University of Washington, Seattle, WA 98195-7280, United States.
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44
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Marrone GF, Lu Z, Rossi G, Narayan A, Hunkele A, Marx S, Xu J, Pintar J, Majumdar S, Pan YX, Pasternak GW. Tetrapeptide Endomorphin Analogs Require Both Full Length and Truncated Splice Variants of the Mu Opioid Receptor Gene Oprm1 for Analgesia. ACS Chem Neurosci 2016; 7:1717-1727. [PMID: 27648914 DOI: 10.1021/acschemneuro.6b00240] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022] Open
Abstract
The mu opioid receptor gene undergoes extensive alternative splicing. Mu opioids can be divided into three classes based on the role of different groups of splice variants. Morphine and methadone require only full length seven transmembrane (7TM) variants for analgesia, whereas IBNtxA (3'-iodobenzyol-6β-naltrexamide) needs only truncated 6TM variants. A set of endomorphin analogs fall into a third group that requires both 6TM and 7TM splice variants. Unlike morphine, endomorphin 1 and 2, DAPP (Dmt,d-Ala-Phe-Phe-NH2), and IDAPP (3'-iodo-Dmt-d-Ala-Phe-Phe-NH2) analgesia was lost in an exon 11 knockout mouse lacking 6TM variants. Restoring 6TM variant expression in a knockout mouse lacking both 6TM and 7TM variants failed to rescue DAPP or IDAPP analgesia. However, re-establishing 6TM expression in an exon 11 knockout mouse that still expressed 7TM variants did rescue the response, consistent with the need for both 6TM and 7TM variants. In receptor binding assays, 125I-IDAPP labeled more sites (Bmax) than 3H-DAMGO ([d-Ala2,N-MePhe4,Gly(ol)5]-enkephalin) in wild-type mice. In exon 11 knockout mice, 125I-IDAPP binding was lowered to levels similar to 3H-DAMGO, which remained relatively unchanged compared to wild-type mice. 125I-IDAPP binding was totally lost in an exon 1/exon 11 knockout model lacking all Oprm1 variant expression, confirming that the drug was not cross labeling non-mu opioid receptors. These findings suggested that 125I-IDAPP labeled two populations of mu binding sites in wild-type mice, one corresponding to 7TM variants and the second dependent upon 6TM variants. Together, these data indicate that endomorphin analogs represent a unique, genetically defined, and distinct class of mu opioid analgesic.
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Affiliation(s)
- Gina F. Marrone
- Department
of Neurology and Molecular Pharmacology Program, Memorial Sloan Kettering Cancer Center, New York, New York 10065, United States
- Neuroscience
and Pharmacology Graduate Program, Weill Cornell Graduate School of Medical Sciences, New York, New York 10065, United States
| | - Zhigang Lu
- Department
of Neurology and Molecular Pharmacology Program, Memorial Sloan Kettering Cancer Center, New York, New York 10065, United States
| | - Grace Rossi
- Long Island University, Post
Campus, Brookville, New York 11548, United States
| | - Ankita Narayan
- Department
of Neurology and Molecular Pharmacology Program, Memorial Sloan Kettering Cancer Center, New York, New York 10065, United States
- Neuroscience
and Pharmacology Graduate Program, Weill Cornell Graduate School of Medical Sciences, New York, New York 10065, United States
| | - Amanda Hunkele
- Department
of Neurology and Molecular Pharmacology Program, Memorial Sloan Kettering Cancer Center, New York, New York 10065, United States
| | - Sarah Marx
- Department
of Neurology and Molecular Pharmacology Program, Memorial Sloan Kettering Cancer Center, New York, New York 10065, United States
| | - Jin Xu
- Department
of Neurology and Molecular Pharmacology Program, Memorial Sloan Kettering Cancer Center, New York, New York 10065, United States
| | - John Pintar
- Department
of Neuroscience and Cell Biology, UMDNJ-Robert Wood Johnson Medical School, Piscataway, New Jersey 08854, United States
| | - Susruta Majumdar
- Department
of Neurology and Molecular Pharmacology Program, Memorial Sloan Kettering Cancer Center, New York, New York 10065, United States
| | - Ying-Xian Pan
- Department
of Neurology and Molecular Pharmacology Program, Memorial Sloan Kettering Cancer Center, New York, New York 10065, United States
| | - Gavril W. Pasternak
- Department
of Neurology and Molecular Pharmacology Program, Memorial Sloan Kettering Cancer Center, New York, New York 10065, United States
- Neuroscience
and Pharmacology Graduate Program, Weill Cornell Graduate School of Medical Sciences, New York, New York 10065, United States
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45
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Grinnell SG, Ansonoff M, Marrone GF, Lu Z, Narayan A, Xu J, Rossi G, Majumdar S, Pan YX, Bassoni DL, Pintar J, Pasternak GW. Mediation of buprenorphine analgesia by a combination of traditional and truncated mu opioid receptor splice variants. Synapse 2016; 70:395-407. [PMID: 27223691 PMCID: PMC4980214 DOI: 10.1002/syn.21914] [Citation(s) in RCA: 39] [Impact Index Per Article: 4.9] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/21/2016] [Revised: 04/21/2016] [Accepted: 05/22/2016] [Indexed: 01/17/2023]
Abstract
Buprenorphine has long been classified as a mu analgesic, although its high affinity for other opioid receptor classes and the orphanin FQ/nociceptin ORL1 receptor may contribute to its other actions. The current studies confirmed a mu mechanism for buprenorphine analgesia, implicating several subsets of mu receptor splice variants. Buprenorphine analgesia depended on the expression of both exon 1-associated traditional full length 7 transmembrane (7TM) and exon 11-associated truncated 6 transmembrane (6TM) MOR-1 variants. In genetic models, disruption of delta, kappa1 or ORL1 receptors had no impact on buprenorphine analgesia, while loss of the traditional 7TM MOR-1 variants in an exon 1 knockout (KO) mouse markedly lowered buprenorphine analgesia. Loss of the truncated 6TM variants in an exon 11 KO mouse totally eliminated buprenorphine analgesia. In distinction to analgesia, the inhibition of gastrointestinal transit and stimulation of locomotor activity were independent of truncated 6TM variants. Restoring expression of a 6TM variant with a lentivirus rescued buprenorphine analgesia in an exon 11 KO mouse that still expressed the 7TM variants. Despite a potent and robust stimulation of (35) S-GTPγS binding in MOR-1 expressing CHO cells, buprenorphine failed to recruit β-arrestin-2 binding at doses as high as 10 µM. Buprenorphine was an antagonist in DOR-1 expressing cells and an inverse agonist in KOR-1 cells. Buprenorphine analgesia is complex and requires multiple mu receptor splice variant classes but other actions may involve alternative receptors.
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Affiliation(s)
- Steven G Grinnell
- Department of Neurology and Molecular Pharmacology and Chemistry Program, Memorial Sloan-Kettering Cancer Center, New York, New York
- Neuroscience Program, Weill Cornell Graduate School of Medical Sciences, New York, New York
| | - Michael Ansonoff
- Department of Neuroscience and Cell Biology, UMDNJ-Robert Wood Johnson Medical School, Piscataway, New Jersey
| | - Gina F Marrone
- Department of Neurology and Molecular Pharmacology and Chemistry Program, Memorial Sloan-Kettering Cancer Center, New York, New York
- Neuroscience Program, Weill Cornell Graduate School of Medical Sciences, New York, New York
| | - Zhigang Lu
- Department of Neurology and Molecular Pharmacology and Chemistry Program, Memorial Sloan-Kettering Cancer Center, New York, New York
| | - Ankita Narayan
- Department of Neurology and Molecular Pharmacology and Chemistry Program, Memorial Sloan-Kettering Cancer Center, New York, New York
- Neuroscience Program, Weill Cornell Graduate School of Medical Sciences, New York, New York
| | - Jin Xu
- Department of Neurology and Molecular Pharmacology and Chemistry Program, Memorial Sloan-Kettering Cancer Center, New York, New York
| | - Grace Rossi
- Department of Psychology, Long Island University, Post Campus, Brookville, New York
| | - Susruta Majumdar
- Department of Neurology and Molecular Pharmacology and Chemistry Program, Memorial Sloan-Kettering Cancer Center, New York, New York
| | - Ying-Xian Pan
- Department of Neurology and Molecular Pharmacology and Chemistry Program, Memorial Sloan-Kettering Cancer Center, New York, New York
| | | | - John Pintar
- Department of Neuroscience and Cell Biology, UMDNJ-Robert Wood Johnson Medical School, Piscataway, New Jersey
| | - Gavril W Pasternak
- Department of Neurology and Molecular Pharmacology and Chemistry Program, Memorial Sloan-Kettering Cancer Center, New York, New York
- Neuroscience Program, Weill Cornell Graduate School of Medical Sciences, New York, New York
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46
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Yang PP, Yeh GC, Yeh TK, Xi J, Loh HH, Law PY, Tao PL. Activation of delta-opioid receptor contributes to the antinociceptive effect of oxycodone in mice. Pharmacol Res 2016; 111:867-876. [DOI: 10.1016/j.phrs.2016.05.034] [Citation(s) in RCA: 17] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 11/17/2015] [Revised: 05/11/2016] [Accepted: 05/11/2016] [Indexed: 10/21/2022]
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47
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Donaldson LF, Beazley-Long N. Alternative RNA splicing: contribution to pain and potential therapeutic strategy. Drug Discov Today 2016; 21:1787-1798. [PMID: 27329269 PMCID: PMC5405051 DOI: 10.1016/j.drudis.2016.06.017] [Citation(s) in RCA: 31] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/23/2016] [Revised: 05/31/2016] [Accepted: 06/14/2016] [Indexed: 12/19/2022]
Abstract
Alternative pre-mRNA splicing generates multiple proteins from a single gene. Control of alternative splicing is a likely therapy in cancer and other disorders. Key molecules in pain pathways – GPCRs and channels – are alternatively spliced. It is proposed that alternative splicing may be a therapeutic target in pain.
Since the sequencing of metazoan genomes began, it has become clear that the number of expressed proteins far exceeds the number of genes. It is now estimated that more than 98% of human genes give rise to multiple proteins through alternative pre-mRNA splicing. In this review, we highlight the known alternative splice variants of many channels, receptors, and growth factors that are important in nociception and pain. Recently, pharmacological control of alternative splicing has been proposed as potential therapy in cancer, wet age-related macular degeneration, retroviral infections, and pain. Thus, we also consider the effects that known splice variants of molecules key to nociception/pain have on nociceptive processing and/or analgesic action, and the potential for control of alternative pre-mRNA splicing as a novel analgesic strategy.
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Affiliation(s)
- Lucy F Donaldson
- School of Life Sciences and Arthritis Research UK Pain Centre, University of Nottingham, Nottingham NG7 2UH, UK.
| | - Nicholas Beazley-Long
- School of Life Sciences and Arthritis Research UK Pain Centre, University of Nottingham, Nottingham NG7 2UH, UK
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48
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Eriksen GS, Andersen JM, Boix F, Bergh MSS, Vindenes V, Rice KC, Huestis MA, Mørland J. Comparison of (+)- and (-)-Naloxone on the Acute Psychomotor-Stimulating Effects of Heroin, 6-Acetylmorphine, and Morphine in Mice. J Pharmacol Exp Ther 2016; 358:209-15. [PMID: 27278234 DOI: 10.1124/jpet.116.233544] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/30/2016] [Accepted: 06/07/2016] [Indexed: 11/22/2022] Open
Abstract
Toll-like receptor 4 (TLR4) signaling is implied in opioid reinforcement, reward, and withdrawal. Here, we explored whether TLR4 signaling is involved in the acute psychomotor-stimulating effects of heroin, 6-acetylmorphine (6-AM), and morphine as well as whether there are differences between the three opioids regarding TLR4 signaling. To address this, we examined how pretreatment with (+)-naloxone, a TLR4 active but opioid receptor (OR) inactive antagonist, affected the acute increase in locomotor activity induced by heroin, 6-AM, or morphine in mice. We also assessed the effect of pretreatment with (-)-naloxone, a TLR4 and OR active antagonist, as well as the pharmacokinetic profiles of (+) and (-)-naloxone in the blood and brain. We found that (-)-naloxone reduced acute opioid-induced locomotor activity in a dose-dependent manner. By contrast, (+)-naloxone, administered in doses assumed to antagonize TLR4 but not ORs, did not affect acute locomotor activity induced by heroin, 6-AM, or morphine. Both naloxone isomers exhibited similar concentration versus time profiles in the blood and brain, but the brain concentrations of (-)-naloxone reached higher levels than those of (+)-naloxone. However, the discrepancies in their pharmacokinetic properties did not explain the marked difference between the two isomers' ability to affect opioid-induced locomotor activity. Our results underpin the importance of OR activation and do not indicate an apparent role of TLR4 signaling in acute opioid-induced psychomotor stimulation in mice. Furthermore, there were no marked differences between heroin, 6-AM, and morphine regarding involvement of OR or TLR4 signaling.
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Affiliation(s)
- Guro Søe Eriksen
- Department of Drug Abuse Research, Division for Forensic Sciences, Norwegian Institute of Public Health, Oslo, Norway (G.S.E., J.M.A., F.B., M.S.-S.B., V.V., J.M.); Institute of Clinical Medicine, University of Oslo, Oslo, Norway (V.V., J.M.); University of Maryland School of Medicine, Baltimore, Maryland (M.A.H.); and Section on Drug Design and Synthesis, National Institute on Drug Abuse and National Institute on Alcohol Abuse and Alcoholism, National Institutes of Health, Bethesda, Maryland (K.C.R)
| | - Jannike Mørch Andersen
- Department of Drug Abuse Research, Division for Forensic Sciences, Norwegian Institute of Public Health, Oslo, Norway (G.S.E., J.M.A., F.B., M.S.-S.B., V.V., J.M.); Institute of Clinical Medicine, University of Oslo, Oslo, Norway (V.V., J.M.); University of Maryland School of Medicine, Baltimore, Maryland (M.A.H.); and Section on Drug Design and Synthesis, National Institute on Drug Abuse and National Institute on Alcohol Abuse and Alcoholism, National Institutes of Health, Bethesda, Maryland (K.C.R)
| | - Fernando Boix
- Department of Drug Abuse Research, Division for Forensic Sciences, Norwegian Institute of Public Health, Oslo, Norway (G.S.E., J.M.A., F.B., M.S.-S.B., V.V., J.M.); Institute of Clinical Medicine, University of Oslo, Oslo, Norway (V.V., J.M.); University of Maryland School of Medicine, Baltimore, Maryland (M.A.H.); and Section on Drug Design and Synthesis, National Institute on Drug Abuse and National Institute on Alcohol Abuse and Alcoholism, National Institutes of Health, Bethesda, Maryland (K.C.R)
| | - Marianne Skov-Skov Bergh
- Department of Drug Abuse Research, Division for Forensic Sciences, Norwegian Institute of Public Health, Oslo, Norway (G.S.E., J.M.A., F.B., M.S.-S.B., V.V., J.M.); Institute of Clinical Medicine, University of Oslo, Oslo, Norway (V.V., J.M.); University of Maryland School of Medicine, Baltimore, Maryland (M.A.H.); and Section on Drug Design and Synthesis, National Institute on Drug Abuse and National Institute on Alcohol Abuse and Alcoholism, National Institutes of Health, Bethesda, Maryland (K.C.R)
| | - Vigdis Vindenes
- Department of Drug Abuse Research, Division for Forensic Sciences, Norwegian Institute of Public Health, Oslo, Norway (G.S.E., J.M.A., F.B., M.S.-S.B., V.V., J.M.); Institute of Clinical Medicine, University of Oslo, Oslo, Norway (V.V., J.M.); University of Maryland School of Medicine, Baltimore, Maryland (M.A.H.); and Section on Drug Design and Synthesis, National Institute on Drug Abuse and National Institute on Alcohol Abuse and Alcoholism, National Institutes of Health, Bethesda, Maryland (K.C.R)
| | - Kenner C Rice
- Department of Drug Abuse Research, Division for Forensic Sciences, Norwegian Institute of Public Health, Oslo, Norway (G.S.E., J.M.A., F.B., M.S.-S.B., V.V., J.M.); Institute of Clinical Medicine, University of Oslo, Oslo, Norway (V.V., J.M.); University of Maryland School of Medicine, Baltimore, Maryland (M.A.H.); and Section on Drug Design and Synthesis, National Institute on Drug Abuse and National Institute on Alcohol Abuse and Alcoholism, National Institutes of Health, Bethesda, Maryland (K.C.R)
| | - Marilyn A Huestis
- Department of Drug Abuse Research, Division for Forensic Sciences, Norwegian Institute of Public Health, Oslo, Norway (G.S.E., J.M.A., F.B., M.S.-S.B., V.V., J.M.); Institute of Clinical Medicine, University of Oslo, Oslo, Norway (V.V., J.M.); University of Maryland School of Medicine, Baltimore, Maryland (M.A.H.); and Section on Drug Design and Synthesis, National Institute on Drug Abuse and National Institute on Alcohol Abuse and Alcoholism, National Institutes of Health, Bethesda, Maryland (K.C.R)
| | - Jørg Mørland
- Department of Drug Abuse Research, Division for Forensic Sciences, Norwegian Institute of Public Health, Oslo, Norway (G.S.E., J.M.A., F.B., M.S.-S.B., V.V., J.M.); Institute of Clinical Medicine, University of Oslo, Oslo, Norway (V.V., J.M.); University of Maryland School of Medicine, Baltimore, Maryland (M.A.H.); and Section on Drug Design and Synthesis, National Institute on Drug Abuse and National Institute on Alcohol Abuse and Alcoholism, National Institutes of Health, Bethesda, Maryland (K.C.R)
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Truncated mu opioid GPCR variant involvement in opioid-dependent and opioid-independent pain modulatory systems within the CNS. Proc Natl Acad Sci U S A 2016; 113:3663-8. [PMID: 26976581 DOI: 10.1073/pnas.1523894113] [Citation(s) in RCA: 23] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/26/2023] Open
Abstract
The clinical management of severe pain depends heavily on opioids acting through mu opioid receptors encoded by the Oprm1 gene, which undergoes extensive alternative splicing. In addition to generating a series of prototypic seven transmembrane domain (7TM) G protein-coupled receptors (GPCRs), Oprm1 also produces a set of truncated splice variants containing only six transmembrane domains (6TM) through which selected opioids such as IBNtxA (3'-iodobenzoyl-6β-naltrexamide) mediate a potent analgesia without many undesirable effects. Although morphine analgesia is independent of these 6TM mu receptor isoforms, we now show that the selective loss of the 6TM variants in a knockout model eliminates the analgesic actions of delta and kappa opioids and of α2-adrenergic compounds, but not cannabinoid, neurotensin, or muscarinic drugs. These observations were confirmed by using antisense paradigms. Despite their role in analgesia, loss of the 6TM variants were not involved with delta opioid-induced seizure activity, aversion to the kappa drug U50, 488H, or α2-mediated hypolocomotion. These observations support the existence of parallel opioid and nonopioid pain modulatory systems and highlight the ability to dissociate unwanted delta, kappa1, and α2 actions from analgesia.
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Chakrabarti S, Madia PA, Gintzler AR. Selective up-regulation of functional mu-opioid receptor splice variants by chronic opioids. J Neurochem 2016; 136:1119-1130. [PMID: 26718622 DOI: 10.1111/jnc.13519] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/14/2015] [Revised: 12/15/2015] [Accepted: 12/18/2015] [Indexed: 11/28/2022]
Abstract
We recently reported (Verzillo, et al. J. Neurochem: 130, 790-796, 2014) that chronic systemic morphine selectively up-regulates mRNA encoding two C-terminal μ-opioid receptor (MOR) splice variants, MOR-1C1 and MOR-1B2 (MOR-1B2/-1C1). Given the known disconnects between changes in levels of mRNA and corresponding protein, it is essential to directly demonstrate that chronic opioid treatment elevates functional MOR-1B2/-1C1 protein prior to inferring relevance of these MOR variants to spinal opioid tolerance mechanisms. Accordingly, we investigated the ability of chronic opioid exposure to up-regulate MOR protein in Chinese hamster ovary cells stably transfected with rat MOR variants MOR-1B2, MOR-1C1, or MOR-1 (considered to be the predominant MOR). Findings revealed that chronic treatment with the clinically relevant opioids morphine, oxycodone and hydrocodone substantially up-regulated membrane MOR-1B2/-1C1 protein. This up-regulation was abolished by the protein synthesis inhibitor cycloheximide, eliminating contributions from receptor redistribution. The increment in MOR-1B2/-1C1 protein was paralleled by a significant increment in opioid agonist-stimulated GTPγS-binding (reflective of increased aggregate MOR G protein coupling) indicating that up-regulated MOR-1B2/-1C1 represented functional receptors. Strikingly, these tolerance-associated adaptations of MOR-1B2/-1C1 differed considerably from those of MOR-1. Antithetical regulation of MOR-1B2/-1C1 and MOR-1 by chronic opioids has significant implications for the design of new therapeutic agents to counteract opioid analgesic tolerance and accompanying addiction. Since chronic opioids induce MOR-1B2/-1C1 up-regulation in spinal cord of males, but not females, elucidating cellular compartments and intracellular pathways mediating MOR-1B2/-1C1 up-regulation and defining their unique signaling attributes would enable a precision medicinal approach to pain management and addiction therapy. In the spinal cord of males, but not females, chronic morphine up-regulates mRNA encoding two mu-opioid receptor (MOR) variants, MOR-1B2 and MOR-1C1 (MOR-1B2/-1C1). We now demonstrate that chronic treatment with the clinically relevant opioids morphine, hydrocodone or oxycodone up-regulates MOR-1B2/-1C1 functional protein, which is dependent on de novo protein synthesis. Findings underscore the importance of unique signaling attributes of MOR variants to sexually dimorphic tolerance mechanisms.
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Affiliation(s)
- Sumita Chakrabarti
- Department of Obstetrics and Gynecology, State University of New York, Brooklyn, New York, USA
| | - Priyanka A Madia
- Department of Obstetrics and Gynecology, State University of New York, Brooklyn, New York, USA
| | - Alan R Gintzler
- Department of Obstetrics and Gynecology, State University of New York, Brooklyn, New York, USA
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