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Yu J, Kumar A, Zhang X, Martin C, Van Holsbeeck K, Raia P, Koehl A, Laeremans T, Steyaert J, Manglik A, Ballet S, Boland A, Stoeber M. Structural basis of μ-opioid receptor targeting by a nanobody antagonist. Nat Commun 2024; 15:8687. [PMID: 39384768 PMCID: PMC11464722 DOI: 10.1038/s41467-024-52947-6] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/16/2023] [Accepted: 09/24/2024] [Indexed: 10/11/2024] Open
Abstract
The μ-opioid receptor (μOR), a prototypical G protein-coupled receptor (GPCR), is the target of opioid analgesics such as morphine and fentanyl. Due to the severe side effects of current opioid drugs, there is considerable interest in developing novel modulators of μOR function. Most GPCR ligands today are small molecules, however biologics, including antibodies and nanobodies, represent alternative therapeutics with clear advantages such as affinity and target selectivity. Here, we describe the nanobody NbE, which selectively binds to the μOR and acts as an antagonist. We functionally characterize NbE as an extracellular and genetically encoded μOR ligand and uncover the molecular basis for μOR antagonism by determining the cryo-EM structure of the NbE-μOR complex. NbE displays a unique ligand binding mode and achieves μOR selectivity by interactions with the orthosteric pocket and extracellular receptor loops. Based on a β-hairpin loop formed by NbE that deeply protrudes into the μOR, we design linear and cyclic peptide analogs that recapitulate NbE's antagonism. The work illustrates the potential of nanobodies to uniquely engage with GPCRs and describes lower molecular weight μOR ligands that can serve as a basis for therapeutic developments.
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MESH Headings
- Receptors, Opioid, mu/metabolism
- Receptors, Opioid, mu/chemistry
- Receptors, Opioid, mu/antagonists & inhibitors
- Single-Domain Antibodies/chemistry
- Single-Domain Antibodies/metabolism
- Single-Domain Antibodies/pharmacology
- Humans
- Cryoelectron Microscopy
- Ligands
- HEK293 Cells
- Animals
- Protein Binding
- Binding Sites
- Models, Molecular
- Analgesics, Opioid/pharmacology
- Analgesics, Opioid/chemistry
- Analgesics, Opioid/metabolism
- Peptides, Cyclic/chemistry
- Peptides, Cyclic/metabolism
- Peptides, Cyclic/pharmacology
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Affiliation(s)
- Jun Yu
- Department of Molecular and Cellular Biology, University of Geneva, Geneva, Switzerland
| | - Amit Kumar
- Department of Cell Physiology and Metabolism, University of Geneva, Geneva, Switzerland
| | - Xuefeng Zhang
- Department of Molecular and Cellular Biology, University of Geneva, Geneva, Switzerland
| | - Charlotte Martin
- Departments of Chemistry and Bioengineering Sciences, Vrije Universiteit Brussel, Brussels, Belgium
| | - Kevin Van Holsbeeck
- Departments of Chemistry and Bioengineering Sciences, Vrije Universiteit Brussel, Brussels, Belgium
| | - Pierre Raia
- Department of Plant Sciences, University of Geneva, Geneva, Switzerland
| | - Antoine Koehl
- Department of Electrical Engineering and Computer Sciences, University of California, Berkeley, CA, USA
| | | | - Jan Steyaert
- Structural Biology Brussels, Vrije Universiteit Brussel, Brussels, Belgium
- VIB-VUB Center for Structural Biology, VIB, Brussels, Belgium
| | - Aashish Manglik
- Department of Pharmaceutical Chemistry, University of California, San Francisco, CA, USA
| | - Steven Ballet
- Departments of Chemistry and Bioengineering Sciences, Vrije Universiteit Brussel, Brussels, Belgium
| | - Andreas Boland
- Department of Molecular and Cellular Biology, University of Geneva, Geneva, Switzerland.
| | - Miriam Stoeber
- Department of Cell Physiology and Metabolism, University of Geneva, Geneva, Switzerland.
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Carr JA, Morgan DJ. Methocinnamox is a Potent and Long-Acting Antagonist that can Prevent and Reverse Opioid-Induced Respiratory Depression. J Pharmacol Exp Ther 2024; 391:1-3. [PMID: 39293858 DOI: 10.1124/jpet.124.002205] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/17/2024] [Accepted: 03/28/2024] [Indexed: 09/20/2024] Open
Affiliation(s)
- James A Carr
- Department of Biology, Texas Tech University, Lubbock, Texas (J.A.C.) and Department of Biomedical Sciences, Marshall University, Huntington, West Virginia (D.J.M.)
| | - Daniel J Morgan
- Department of Biology, Texas Tech University, Lubbock, Texas (J.A.C.) and Department of Biomedical Sciences, Marshall University, Huntington, West Virginia (D.J.M.)
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3
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Ghodrati S, Carey LM, France CP. Antinociceptive effects of fentanyl and nonopioid drugs in methocinnamox-treated rats. Drug Alcohol Depend 2024; 260:111320. [PMID: 38723374 DOI: 10.1016/j.drugalcdep.2024.111320] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 01/08/2024] [Revised: 04/18/2024] [Accepted: 04/22/2024] [Indexed: 06/16/2024]
Abstract
BACKGROUND A single administration of the opioid receptor antagonist methocinnamox (MCAM) antagonizes the antinociceptive effects of µ-opioid receptor agonists for 2 weeks or longer. Such a long duration of antagonism could necessitate the use of nonopioid drugs for treating pain in patients receiving MCAM for opioid use disorder (OUD). METHODS The antinociceptive effects of fentanyl and nonopioid drugs were assessed in 24 male Sprague Dawley rats using a complete Freund's adjuvant (CFA) model of inflammatory pain. Twelve rats received 10mg/kg MCAM and 12 received vehicle; half (n=6) of the animals from each treatment group were treated (intraplantar) with CFA or saline. Hypersensitivity to mechanical stimulation was measured using a von Frey anesthesiometer. Fentanyl (0.01-0.1mg/kg), ketamine (17.8-56mg/kg), gabapentin (32-100mg/kg), meloxicam (3.2-10mg/kg), and ∆9-tetrahydrocannabinol (THC, 1-10mg/kg) were administered intraperitoneally and tested every 3 days in a pseudorandom order. Next, the same drugs were studied for effects on motor performance using a rotarod apparatus. RESULTS CFA-induced hypersensitivity was attenuated by fentanyl in vehicle- but not MCAM-treated rats. THC, ketamine, and gabapentin attenuated (up to 82, 66, and 46 %, respectively) CFA-evoked mechanical hypersensitivity in both MCAM- and vehicle-treated rats. Meloxicam failed to alter CFA-evoked mechanical hypersensitivity in either group. Fentanyl, THC, gabapentin, and meloxicam did not affect motor performance in either group whereas ketamine impaired motor performance in both groups (up to 71 % reduction in latency to fall). CONCLUSIONS These data suggest that ketamine, gabapentin, and THC could be effective for treating inflammatory pain under conditions of long term µ-opioid receptor antagonism.
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Affiliation(s)
- Saba Ghodrati
- Department of Pharmacology, University of Texas Health Science Center, San Antonio, TX 78229, USA; Addiction Research, Treatment & Training Center of Excellence, University of Texas Health Science Center, San Antonio, TX 78229, USA
| | - Lawrence M Carey
- Department of Pharmacology, University of Texas Health Science Center, San Antonio, TX 78229, USA; Addiction Research, Treatment & Training Center of Excellence, University of Texas Health Science Center, San Antonio, TX 78229, USA
| | - Charles P France
- Department of Pharmacology, University of Texas Health Science Center, San Antonio, TX 78229, USA; Addiction Research, Treatment & Training Center of Excellence, University of Texas Health Science Center, San Antonio, TX 78229, USA; Department of Psychiatry, University of Texas Health Science Center, San Antonio, TX 78229, USA.
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Tsai MHM, Chen L, Baumann MH, Canals M, Javitch JA, Lane JR, Shi L. In Vitro Functional Profiling of Fentanyl and Nitazene Analogs at the μ-Opioid Receptor Reveals High Efficacy for Gi Protein Signaling. ACS Chem Neurosci 2024; 15:854-867. [PMID: 38345920 DOI: 10.1021/acschemneuro.3c00750] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/22/2024] Open
Abstract
Novel synthetic opioids (NSOs), including both fentanyl and non-fentanyl analogs that act as μ-opioid receptor (MOR) agonists, are associated with serious intoxication and fatal overdose. Previous studies proposed that G-protein-biased MOR agonists are safer pain medications, while other evidence indicates that low intrinsic efficacy at MOR better explains the reduced opioid side effects. Here, we characterized the in vitro functional profiles of various NSOs at the MOR using adenylate cyclase inhibition and β-arrestin2 recruitment assays, in conjunction with the application of the receptor depletion approach. By fitting the concentration-response data to the operational model of agonism, we deduced the intrinsic efficacy and affinity for each opioid in the Gi protein signaling and β-arrestin2 recruitment pathways. Compared to the reference agonist [d-Ala2,N-MePhe4,Gly-ol5]enkephalin, we found that several fentanyl analogs were more efficacious at inhibiting cAMP production, whereas all fentanyl analogs were less efficacious at recruiting β-arrestin2. In contrast, the non-fentanyl 2-benzylbenzimidazole (i.e., nitazene) analogs were highly efficacious and potent in both the cAMP and β-arrestin2 assays. Our findings suggest that the high intrinsic efficacy of the NSOs in Gi protein signaling is a common property that may underlie their high risk of intoxication and overdose, highlighting the limitation of using in vitro functional bias to predict the adverse effects of opioids. In addition, the extremely high potency of many NSOs now infiltrating illicit drug markets further contributes to the danger posed to public health.
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Affiliation(s)
- Meng-Hua M Tsai
- Computational Chemistry and Molecular Biophysics Section, Intramural Research Program, National Institute on Drug Abuse, National Institutes of Health, Baltimore, Maryland 21224, United States
| | - Li Chen
- Computational Chemistry and Molecular Biophysics Section, Intramural Research Program, National Institute on Drug Abuse, National Institutes of Health, Baltimore, Maryland 21224, United States
| | - Michael H Baumann
- Designer Drug Research Unit, Intramural Research Program, National Institute on Drug Abuse, National Institutes of Health, Baltimore, Maryland 21224, United States
| | - Meritxell Canals
- Division of Physiology, Pharmacology and Neuroscience, School of Life Sciences, Queen's Medical Centre, University of Nottingham, Nottingham NG7 2UH, U.K
- Centre of Membrane Proteins and Receptors, Universities of Birmingham and Nottingham, Midlands NG7 2UH, U.K
| | - Jonathan A Javitch
- Division of Molecular Therapeutics, New York State Psychiatric Institute, New York, New York 10032, United States
- Department of Molecular Pharmacology and Therapeutics, Vagelos College of Physicians and Surgeons, Columbia University, New York, New York 10032, United States
- Department of Psychiatry, Vagelos College of Physicians and Surgeons, Columbia University, New York, New York 10032, United States
| | - J Robert Lane
- Division of Physiology, Pharmacology and Neuroscience, School of Life Sciences, Queen's Medical Centre, University of Nottingham, Nottingham NG7 2UH, U.K
- Centre of Membrane Proteins and Receptors, Universities of Birmingham and Nottingham, Midlands NG7 2UH, U.K
| | - Lei Shi
- Computational Chemistry and Molecular Biophysics Section, Intramural Research Program, National Institute on Drug Abuse, National Institutes of Health, Baltimore, Maryland 21224, United States
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5
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Maguire DR, France CP. Daily methocinnamox treatment dose-dependently attenuates fentanyl self-administration in rhesus monkeys. Neuropharmacology 2024; 243:109777. [PMID: 37944894 DOI: 10.1016/j.neuropharm.2023.109777] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/11/2023] [Revised: 09/26/2023] [Accepted: 10/22/2023] [Indexed: 11/12/2023]
Abstract
Opioid use disorder and opioid overdose continue to be significant public health challenges despite the availability of effective treatments. Methocinnamox (MCAM) is a novel, long-acting opioid receptor antagonist that might be an effective treatment for opioid use disorder (i.e., preventing relapse and overdose). In nonhuman primates, MCAM selectively blocks the positive reinforcing effects of mu opioid receptor agonists, including heroin, fentanyl, and its ultra-potent analogs (e.g., carfentanil) with a single administration of MCAM being effective for up to two weeks. Because treatment of opioid use disorder would involve repeated administration of a medication, MCAM was studied in rhesus monkeys (3 males and 2 females) responding under a fixed-ratio self-administration procedure for a range of doses of fentanyl (0.000032-0.1 mg/kg/infusion). The fentanyl self-administration dose-effect curve was determined before and during treatment with progressively increasing daily doses of MCAM (0.001-0.1 mg/kg) given subcutaneously 1 h before the session. MCAM dose-dependently shifted the fentanyl dose-effect curve rightward and then, at larger doses, downward. The largest treatment dose of MCAM (0.1 mg/kg/day) shifted the curve more than 120-fold rightward with monkeys receiving doses much larger than the likely lethal dose of fentanyl with no adverse effect or observable change in behavior. This study demonstrates that MCAM reliably and dose-dependently decreases fentanyl self-administration and prevents opioid overdose, with no evidence of adverse effects over a broad dose range, further supporting the potential therapeutic utility of this novel antagonist.
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Affiliation(s)
- David R Maguire
- Department of Pharmacology, University of Texas Health Science Center at San Antonio, 7703 Floyd Curl Dr, San Antonio, TX, 78229, USA; Addiction Research, Treatment & Training Center of Excellence, University of Texas Health Science Center at San Antonio, 7703 Floyd Curl Dr, San Antonio, TX, 78229, USA
| | - Charles P France
- Department of Pharmacology, University of Texas Health Science Center at San Antonio, 7703 Floyd Curl Dr, San Antonio, TX, 78229, USA; Addiction Research, Treatment & Training Center of Excellence, University of Texas Health Science Center at San Antonio, 7703 Floyd Curl Dr, San Antonio, TX, 78229, USA; Department of Psychiatry, University of Texas Health Science Center at San Antonio, 7703 Floyd Curl Dr, San Antonio, TX, 78229, USA.
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Tsai MHM, Chen L, Baumann MH, Canals M, Javitch JA, Lane JR, Shi L. The in vitro functional profiles of fentanyl and nitazene analogs at the μ-opioid receptor - high efficacy is dangerous regardless of signaling bias. BIORXIV : THE PREPRINT SERVER FOR BIOLOGY 2023:2023.11.10.566672. [PMID: 38014284 PMCID: PMC10680598 DOI: 10.1101/2023.11.10.566672] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/29/2023]
Abstract
Novel synthetic opioids (NSOs), including both fentanyl and non-fentanyl analogs that act as the μ-opioid receptor (MOR) agonists, are associated with serious intoxication and fatal overdose. Previous studies proposed that G protein biased MOR agonists are safer pain medications, while other evidence indicates that low intrinsic efficacy at MOR better explains reduced opioid side effects. Here, we characterized the in vitro functional profiles of various NSOs at MOR using adenylate cyclase inhibition and β-arrestin2 recruitment assays, in conjunction with the application of the receptor depletion approach. By fitting the concentration-response data to the operational model of agonism, we deduced the intrinsic efficacy and affinity for each opioid in the Gi protein signaling and β-arrestin2 recruitment pathways. Compared to the reference agonist DAMGO, we found that several fentanyl analogs were more efficacious at inhibiting cAMP production, whereas all fentanyl analogs were less efficacious at recruiting β-arrestin2. In contrast, the non-fentanyl 2-benzylbenzimidazole (i.e., nitazene) analogs were highly efficacious and potent in both the cAMP and β-arrestin2 assays. Our findings suggest that the high intrinsic efficacy of the NSOs in Gi protein signaling is a common property that may underlie their high risk of intoxication and overdose, highlighting the limitation of using in vitro functional bias to predict the adverse effects of opioids. Instead, our results show that, regardless of bias, opioids with sufficiently high intrinsic efficacy can be lethal, especially given the extremely high potency of many of these compounds that are now pervading the illicit drug market.
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Affiliation(s)
- Meng-Hua M. Tsai
- Computational Chemistry and Molecular Biophysics Section, Intramural Research Program, National Institute on Drug Abuse, National Institutes of Health, Baltimore, Maryland 21224, USA
| | - Li Chen
- Computational Chemistry and Molecular Biophysics Section, Intramural Research Program, National Institute on Drug Abuse, National Institutes of Health, Baltimore, Maryland 21224, USA
| | - Michael H. Baumann
- Designer Drug Research Unit, Intramural Research Program, National Institute on Drug Abuse, National Institutes of Health, Baltimore, Maryland 21224, USA
| | - Meritxell Canals
- Division of Physiology, Pharmacology and Neuroscience, School of Life Sciences, Queen’s Medical Centre, University of Nottingham, Nottingham, UK
- Centre of Membrane Proteins and Receptors, Universities of Birmingham and Nottingham, Midlands, UK
| | - Jonathan A. Javitch
- Division of Molecular Therapeutics, New York State Psychiatric Institute, New York, NY 10032, USA
- Department of Molecular Pharmacology and Therapeutics, Vagelos College of Physicians and Surgeons, Columbia University, New York, NY 10032, USA
- Department of Psychiatry, Vagelos College of Physicians and Surgeons, Columbia University, New York, NY 10032, USA
| | - J. Robert Lane
- Division of Physiology, Pharmacology and Neuroscience, School of Life Sciences, Queen’s Medical Centre, University of Nottingham, Nottingham, UK
- Centre of Membrane Proteins and Receptors, Universities of Birmingham and Nottingham, Midlands, UK
| | - Lei Shi
- Computational Chemistry and Molecular Biophysics Section, Intramural Research Program, National Institute on Drug Abuse, National Institutes of Health, Baltimore, Maryland 21224, USA
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Tabanelli R, Brogi S, Calderone V. Targeting Opioid Receptors in Addiction and Drug Withdrawal: Where Are We Going? Int J Mol Sci 2023; 24:10888. [PMID: 37446064 PMCID: PMC10341731 DOI: 10.3390/ijms241310888] [Citation(s) in RCA: 4] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/29/2023] [Revised: 06/14/2023] [Accepted: 06/28/2023] [Indexed: 07/15/2023] Open
Abstract
This review article offers an outlook on the use of opioids as therapeutics for treating several diseases, including cancer and non-cancer pain, and focuses the analysis on the opportunity to target opioid receptors for treating opioid use disorder (OUD), drug withdrawal, and addiction. Unfortunately, as has been well established, the use of opioids presents a plethora of side effects, such as tolerance and physical and physiological dependence. Accordingly, considering the great pharmacological potential in targeting opioid receptors, the identification of opioid receptor ligands devoid of most of the adverse effects exhibited by current therapeutic agents is highly necessary. To this end, herein, we analyze some interesting molecules that could potentially be useful for treating OUD, with an in-depth analysis regarding in vivo studies and clinical trials.
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Affiliation(s)
| | - Simone Brogi
- Department of Pharmacy, University of Pisa, Via Bonanno 6, 56126 Pisa, Italy; (R.T.); (V.C.)
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8
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Bodnar RJ. Endogenous opiates and behavior: 2021. Peptides 2023; 164:171004. [PMID: 36990387 DOI: 10.1016/j.peptides.2023.171004] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 02/26/2023] [Revised: 03/23/2023] [Accepted: 03/23/2023] [Indexed: 03/29/2023]
Abstract
This paper is the forty-fourth consecutive installment of the annual anthological review of research concerning the endogenous opioid system, summarizing articles published during 2021 that studied the behavioral effects of molecular, pharmacological and genetic manipulation of opioid peptides and receptors as well as effects of opioid/opiate agonizts and antagonists. The review is subdivided into the following specific topics: molecular-biochemical effects and neurochemical localization studies of endogenous opioids and their receptors (1), the roles of these opioid peptides and receptors in pain and analgesia in animals (2) and humans (3), opioid-sensitive and opioid-insensitive effects of nonopioid analgesics (4), opioid peptide and receptor involvement in tolerance and dependence (5), stress and social status (6), learning and memory (7), eating and drinking (8), drug abuse and alcohol (9), sexual activity and hormones, pregnancy, development and endocrinology (10), mental illness and mood (11), seizures and neurologic disorders (12), electrical-related activity and neurophysiology (13), general activity and locomotion (14), gastrointestinal, renal and hepatic functions (15), cardiovascular responses (16), respiration and thermoregulation (17), and immunological responses (18).
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Affiliation(s)
- Richard J Bodnar
- Department of Psychology and Neuropsychology Doctoral Sub-Program, Queens College, City University of New York, CUNY, 65-30 Kissena Blvd., Flushing, NY 11367, USA.
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9
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Gerak LR, France CP. Attenuation of the Positive-Reinforcing Effects of Ultra-Potent Fentanyl Analogs, Along with Those of Fentanyl and Heroin, During Daily Treatment with Methocinnamox in Rhesus Monkeys. J Pharmacol Exp Ther 2023; 384:363-371. [PMID: 36575032 PMCID: PMC9976789 DOI: 10.1124/jpet.122.001267] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/11/2022] [Revised: 11/22/2022] [Accepted: 12/13/2022] [Indexed: 12/28/2022] Open
Abstract
Without substantial intervention, the opioid crisis is projected to continue, underscoring the need to develop new treatments for opioid use disorder (OUD). One drug under development is the µ opioid receptor antagonist methocinnamox (MCAM), which appears to offer advantages over currently available medications; however, some questions remain about its potential utility, including its ability to block the effects of ultra-potent fentanyl analogs. The goal of this study was to examine its effectiveness in attenuating the abuse-related effects of the fentanyl analogs carfentanil and 3-methylfentanyl in monkeys responding for food or intravenous infusions under a choice procedure. These drugs were compared with fentanyl, heroin, methamphetamine, and cocaine. Food was preferred over saline, and there was a dose-dependent increase in responding for drug over food with no marked decrease in response rates or number of choice trials completed for any of the six drugs studied. Naltrexone (0.032 mg/kg) antagonized choice of µ opioid receptor agonists, producing rightward shifts in dose-effect curves ranging from 27-fold (carfentanil) to 71-fold (heroin). In contrast, naltrexone was less effective in attenuating choice of methamphetamine or cocaine with curves obtained in the presence of naltrexone shifted <3-fold. Daily treatment with 0.032 mg/kg MCAM also antagonized the effects of opioids, shifting curves 20-fold (fentanyl) to 72-fold (heroin) rightward; MCAM did not significantly change dose-effect curves for methamphetamine or cocaine. Thus, antagonism by MCAM is similar across a variety of µ opioid receptor agonists, including ultra-potent fentanyl analogs, further supporting its potential utility as a treatment for OUD. SIGNIFICANCE STATEMENT: Treatments for opioid use disorder (OUD) should attenuate the effects of a variety of opioids, including emerging threats like the ultra-potent fentanyl analogs. The novel µ opioid receptor antagonist MCAM is being developed to treat OUD because it provides long-lasting blockade of the reinforcing effects of heroin and fentanyl. The current study shows that MCAM attenuates the abuse-related effects of the fentanyl analogs carfentanil and 3-methylfentanyl, further supporting the utility of MCAM as a treatment for OUD.
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Affiliation(s)
- Lisa R Gerak
- Department of Pharmacology (L.R.G., C.P.F.) and Department of Psychiatry (C.P.F.), University of Texas Health Science Center at San Antonio, San Antonio, Texas; and Addiction Research, Treatment, & Training Center of Excellence, University of Texas Health Science Center at San Antonio, San Antonio, Texas (L.R.G., C.P.F.)
| | - Charles P France
- Department of Pharmacology (L.R.G., C.P.F.) and Department of Psychiatry (C.P.F.), University of Texas Health Science Center at San Antonio, San Antonio, Texas; and Addiction Research, Treatment, & Training Center of Excellence, University of Texas Health Science Center at San Antonio, San Antonio, Texas (L.R.G., C.P.F.)
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10
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Maguire DR, France CP. Behavioral pharmacology of methocinnamox: A potential new treatment for opioid overdose and opioid use disorder. J Exp Anal Behav 2023; 119:392-406. [PMID: 36759567 PMCID: PMC10281830 DOI: 10.1002/jeab.831] [Citation(s) in RCA: 3] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/09/2022] [Accepted: 12/28/2022] [Indexed: 02/11/2023]
Abstract
Opioid overdose and opioid use disorder continue to be significant public health challenges despite the availability of effective medications and significant efforts at all levels of society. The emergence of highly potent and efficacious opioids such as fentanyl and its derivatives over the last decade has only exacerbated what was already a substantial problem. Behavioral pharmacology research has proven invaluable for understanding the effects of drugs as well as developing and evaluating pharmacotherapies for disorders involving the central nervous system, including substance abuse disorders. This paper describes a program of research characterizing a potent, selective, and long-lasting mu opioid receptor antagonist, methocinnamox, and evaluating its potential for treating opioid overdose and opioid use disorder. Studies in rodents and nonhuman primates demonstrate that methocinnamox prevents and reverses opioid-induced ventilatory depression and selectively blocks opioid self-administration. This work, taken together with rigorous in vitro and ex vivo studies investigating methocinnamox neuropharmacology, lays a solid foundation for the therapeutic utility of this potentially life-saving medication. Moreover, these studies demonstrate how rigorous behavioral pharmacological studies can be integrated in a broader drug discovery and development research program.
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Affiliation(s)
- David R. Maguire
- Department of Pharmacology, University of Texas Health Science Center at San Antonio, TX, United States
- Addiction Research, Treatment, and Training, Center of Excellence, University of Texas, Health Science Center at San Antonio, TX, United States
| | - Charles P. France
- Department of Pharmacology, University of Texas Health Science Center at San Antonio, TX, United States
- Addiction Research, Treatment, and Training, Center of Excellence, University of Texas, Health Science Center at San Antonio, TX, United States
- Department of Psychiatry, University of Texas, Health Science Center at San Antonio, TX, United States
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11
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Maguire DR, France CP. Effects of Daily Methocinnamox Treatment on Fentanyl Self-Administration in Rhesus Monkeys. J Pharmacol Exp Ther 2022; 382:181-187. [PMID: 35643857 PMCID: PMC9341267 DOI: 10.1124/jpet.122.001233] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/26/2022] [Accepted: 05/04/2022] [Indexed: 08/03/2023] Open
Abstract
Methocinnamox (MCAM), a long-acting μ-opioid receptor antagonist, attenuates the positive reinforcing effects of opioids, such as heroin and fentanyl, suggesting it could be an effective treatment of opioid use disorder (OUD). Because treatment of OUD often involves repeated administration of a medication, this study evaluated effects of daily injections of a relatively small dose of MCAM on fentanyl self-administration and characterized the shift in the fentanyl dose-effect curve. Rhesus monkeys (3 males and 2 females) lever-pressed for intravenous infusions of fentanyl (0.032-10 μg/kg infusion) or cocaine (32-100 μg/kg infusion) under a fixed-ratio 30 schedule. MCAM (0.032 mg/kg) or naltrexone (0.0032-0.032 mg/kg) was administered subcutaneously 60 or 15 minutes, respectively, before sessions. When administered acutely, naltrexone and MCAM decreased fentanyl self-administration, with effects of naltrexone lasting less than 24 hours and effects of MCAM lasting for up to 3 days. Daily MCAM treatment attenuated responding for fentanyl, but not cocaine; effects were maintained for the duration of treatment with responding recovering quickly (within 2 days) following discontinuation of treatment. MCAM treatment shifted the fentanyl dose-effect curve in a parallel manner approximately 20-fold to the right. Naltrexone pretreatment decreased fentanyl intake with equal potency before and after MCAM treatment, confirming sensitivity of responding to antagonism by an opioid receptor antagonist. Although antagonist effects of treatment with a relatively small dose were surmountable, MCAM produced sustained and selective attenuation of opioid self-administration, supporting the view that it could be an effective treatment of OUD. SIGNIFICANCE STATEMENT: Opioid use disorder and opioid overdose continue to be significant public health challenges despite the availability of effective treatments. Methocinnamox (MCAM) is a long-acting μ-opioid receptor antagonist that blocks the reinforcing and ventilatory depressant effects of opioids in nonhuman subjects. This study demonstrates that daily treatment with MCAM reliably and selectively decreases fentanyl self-administration, further supporting the potential therapeutic utility of this novel antagonist.
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Affiliation(s)
- David R Maguire
- Department of Pharmacology, (D.R.M., C.P.F.), Addiction Research, Treatment & Training Center of Excellence (D.R.M., C.P.F.), and Department of Psychiatry (C.P.F.), University of Texas Health Science Center at San Antonio, San Antonio, Texas
| | - Charles P France
- Department of Pharmacology, (D.R.M., C.P.F.), Addiction Research, Treatment & Training Center of Excellence (D.R.M., C.P.F.), and Department of Psychiatry (C.P.F.), University of Texas Health Science Center at San Antonio, San Antonio, Texas
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The Potential of Methocinnamox as a Future Treatment for Opioid Use Disorder: A Narrative Review. PHARMACY 2022; 10:pharmacy10030048. [PMID: 35645327 PMCID: PMC9149874 DOI: 10.3390/pharmacy10030048] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/10/2022] [Revised: 04/15/2022] [Accepted: 04/16/2022] [Indexed: 02/01/2023] Open
Abstract
The opioid epidemic is an ongoing public health crisis, and the United States health system is overwhelmed with increasing numbers of opioid-related overdoses. Methocinnamox (MCAM) is a novel mu opioid receptor antagonist with an extended duration of action. MCAM has potential to reduce the burden of the opioid epidemic by being used as an overdose rescue treatment and a long-term treatment for opioid use disorder (OUD). The currently available treatments for OUD include naloxone, naltrexone, and methadone. These treatments have certain limitations, which include short duration of action, patient non-compliance, and diversion. A narrative review was conducted using PubMed and Google Scholar databases covering the history of the opioid epidemic, pain receptors, current OUD treatments and the novel drug MCAM. MCAM could potentially be used as both a rescue and long-term treatment for opioid misuse. This is due to its pseudo-irreversible antagonism of the mu opioid receptor, abnormally long duration of action of nearly two weeks, and the possibility of using kappa or delta opioid receptor agonists for pain management during OUD treatment. MCAM’s novel pharmacokinetic and pharmacodynamic properties open a new avenue for treating opioid misuse.
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