51
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Tyukhtenko S, Ma X, Rajarshi G, Karageorgos I, Anderson KW, Hudgens JW, Guo JJ, Nasr ML, Zvonok N, Vemuri K, Wagner G, Makriyannis A. Conformational gating, dynamics and allostery in human monoacylglycerol lipase. Sci Rep 2020; 10:18531. [PMID: 33116203 PMCID: PMC7595040 DOI: 10.1038/s41598-020-75497-5] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/31/2019] [Accepted: 10/08/2020] [Indexed: 11/09/2022] Open
Abstract
Inhibition of human Monoacylglycerol Lipase (hMGL) offers a novel approach for treating neurological diseases. The design of inhibitors, targeting active-inactive conformational transitions of the enzyme, can be aided by understanding the interplay between structure and dynamics. Here, we report the effects of mutations within the catalytic triad on structure, conformational gating and dynamics of hMGL by combining kinetics, NMR, and HDX-MS data with metadynamics simulations. We found that point mutations alter delicate conformational equilibria between active and inactive states. HDX-MS reveals regions of the hMGL that become substantially more dynamic upon substitution of catalytic acid Asp-239 by alanine. These regions, located far from the catalytic triad, include not only loops but also rigid α-helixes and β-strands, suggesting their involvement in allosteric regulation as channels for long-range signal transmission. The results identify the existence of a preorganized global communication network comprising of tertiary (residue-residue contacts) and quaternary (rigid-body contacts) networks that mediate robust, rapid intraprotein signal transmission. Catalytic Asp-239 controls hMGL allosteric communications and may be considered as an essential residue for the integration and transmission of information to enzymes' remote regions, in addition to its well-known role to facilitate Ser-122 activation. Our findings may assist in the identification of new druggable sites in hMGL.
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Affiliation(s)
- Sergiy Tyukhtenko
- Center for Drug Discovery and Departments of Pharmaceutical Sciences and Chemistry and Chemical Biology, Northeastern University, Boston, MA, 02115-5000, USA.
| | - Xiaoyu Ma
- Center for Drug Discovery and Departments of Pharmaceutical Sciences and Chemistry and Chemical Biology, Northeastern University, Boston, MA, 02115-5000, USA
| | - Girija Rajarshi
- Center for Drug Discovery and Departments of Pharmaceutical Sciences and Chemistry and Chemical Biology, Northeastern University, Boston, MA, 02115-5000, USA
| | - Ioannis Karageorgos
- BioProcess Measurements Group, Biomolecular Measurement Division, National Institute of Standards & Technology, Rockville, MD, 20850, USA.,Institute for Bioscience and Biotechnology Research, 9600 Gudelsky Drive, Rockville, MD, 20850, USA
| | - Kyle W Anderson
- BioProcess Measurements Group, Biomolecular Measurement Division, National Institute of Standards & Technology, Rockville, MD, 20850, USA.,Institute for Bioscience and Biotechnology Research, 9600 Gudelsky Drive, Rockville, MD, 20850, USA
| | - Jeffrey W Hudgens
- BioProcess Measurements Group, Biomolecular Measurement Division, National Institute of Standards & Technology, Rockville, MD, 20850, USA.,Institute for Bioscience and Biotechnology Research, 9600 Gudelsky Drive, Rockville, MD, 20850, USA
| | - Jason J Guo
- Center for Drug Discovery and Departments of Pharmaceutical Sciences and Chemistry and Chemical Biology, Northeastern University, Boston, MA, 02115-5000, USA.,Barnett Institute for Chemical and Biological Analysis, Northeastern University, Boston, MA, 02115-5000, USA
| | - Mahmoud L Nasr
- Department of Biological Chemistry and Molecular Pharmacology, Harvard Medical School, Boston, MA, 02115, USA.,Renal Division and Division of Engineering in Medicine, Department of Medicine, Brigham and Women's Hospital, Harvard Medical School, Boston, MA, 02115, USA
| | - Nikolai Zvonok
- Center for Drug Discovery and Departments of Pharmaceutical Sciences and Chemistry and Chemical Biology, Northeastern University, Boston, MA, 02115-5000, USA
| | - Kiran Vemuri
- Center for Drug Discovery and Departments of Pharmaceutical Sciences and Chemistry and Chemical Biology, Northeastern University, Boston, MA, 02115-5000, USA
| | - Gerhard Wagner
- Department of Biological Chemistry and Molecular Pharmacology, Harvard Medical School, Boston, MA, 02115, USA
| | - Alexandros Makriyannis
- Center for Drug Discovery and Departments of Pharmaceutical Sciences and Chemistry and Chemical Biology, Northeastern University, Boston, MA, 02115-5000, USA.
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52
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Pertwee RG. The 90th Birthday of Professor Raphael Mechoulam, a Top Cannabinoid Scientist and Pioneer. Int J Mol Sci 2020; 21:ijms21207653. [PMID: 33081122 PMCID: PMC7593926 DOI: 10.3390/ijms21207653] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/13/2020] [Accepted: 10/14/2020] [Indexed: 11/16/2022] Open
Affiliation(s)
- Roger G Pertwee
- School of Medical Sciences, The Institute of Medical Sciences, University of Aberdeen, Aberdeen AB25 2ZD, UK
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53
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Iyer V, Slivicki RA, Thomaz AC, Crystal JD, Mackie K, Hohmann AG. The cannabinoid CB 2 receptor agonist LY2828360 synergizes with morphine to suppress neuropathic nociception and attenuates morphine reward and physical dependence. Eur J Pharmacol 2020; 886:173544. [PMID: 32896549 DOI: 10.1016/j.ejphar.2020.173544] [Citation(s) in RCA: 26] [Impact Index Per Article: 6.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/29/2020] [Revised: 09/02/2020] [Accepted: 09/03/2020] [Indexed: 12/12/2022]
Abstract
The opioid crisis has underscored the urgent need to identify safe and effective therapeutic strategies to overcome opioid-induced liabilities. We recently reported that LY2828360, a slowly signaling G protein-biased cannabinoid CB2 receptor agonist, suppresses neuropathic nociception and attenuates the development of tolerance to the opioid analgesic morphine in paclitaxel-treated mice. Whether beneficial effects of LY2828360 are dependent upon the presence of a pathological pain state are unknown and its impact on unwanted opioid-induced side-effects have never been investigated. Here, we asked whether LY2828360 would produce synergistic anti-allodynic effects with morphine in a paclitaxel model of chemotherapy-induced neuropathic pain and characterized its impact on opioid-induced reward and other unwanted side-effects associated with chronic opioid administration. Isobolographic analysis revealed that combinations of LY2828360 and morphine produced synergistic anti-allodynic effects in suppressing paclitaxel-induced mechanical allodynia. In wildtype (WT) mice, LY2828360 blocked morphine-induced reward in a conditioned place preference assay without producing reward or aversion when administered alone. The LY2828360-induced attenuation of morphine-induced reward was absent in CB2 knockout (CB2KO) mice. In the absence of a neuropathic pain state, LY2828360 partially attenuated naloxone-precipitated opioid withdrawal in morphine-dependent WT mice, and this withdrawal was itself markedly exacerbated in CB2KO mice. Moreover, LY2828360 did not reliably alter morphine-induced slowing of colonic transit or attenuate tolerance to morphine antinociceptive efficacy in the hot plate test of acute nociception. Our results suggest that cannabinoid CB2 receptor activation enhances the therapeutic properties of opioids while attenuating unwanted side-effects such as reward and dependence that occur with sustained opioid treatment.
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Affiliation(s)
- Vishakh Iyer
- Program in Neuroscience, Indiana University, Bloomington, IN, USA; Department of Psychological and Brain Sciences, Indiana University, Bloomington, IN, USA
| | - Richard A Slivicki
- Program in Neuroscience, Indiana University, Bloomington, IN, USA; Department of Psychological and Brain Sciences, Indiana University, Bloomington, IN, USA
| | - Ana C Thomaz
- Program in Neuroscience, Indiana University, Bloomington, IN, USA; Genome, Cellular and Developmental Biology Program, Indiana University, Bloomington, IN, USA
| | - Jonathon D Crystal
- Program in Neuroscience, Indiana University, Bloomington, IN, USA; Department of Psychological and Brain Sciences, Indiana University, Bloomington, IN, USA
| | - Ken Mackie
- Program in Neuroscience, Indiana University, Bloomington, IN, USA; Department of Psychological and Brain Sciences, Indiana University, Bloomington, IN, USA; Genome, Cellular and Developmental Biology Program, Indiana University, Bloomington, IN, USA; Gill Center for Biomolecular Science, Indiana University, Bloomington, IN, USA
| | - Andrea G Hohmann
- Program in Neuroscience, Indiana University, Bloomington, IN, USA; Department of Psychological and Brain Sciences, Indiana University, Bloomington, IN, USA; Genome, Cellular and Developmental Biology Program, Indiana University, Bloomington, IN, USA; Gill Center for Biomolecular Science, Indiana University, Bloomington, IN, USA.
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54
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Abstract
The endocannabinoid system (ECS) is a highly versatile signaling system within the nervous system. Despite its widespread localization, its functions within the context of distinct neural processes are very well discernable and specific. This is remarkable, and the question remains as to how such specificity is achieved. One key player in the ECS is the cannabinoid type 1 receptor (CB1), a G protein-coupled receptor characterized by the complexity of its cell-specific expression, cellular and subcellular localization, and its adaptable regulation of intracellular signaling cascades. CB1 receptors are involved in different synaptic and cellular plasticity processes and in the brain's bioenergetics in a context-specific manner. CB2 receptors are also important in several processes in neurons, glial cells, and immune cells of the brain. As polymorphisms in ECS components, as well as external impacts such as stress and metabolic challenges, can both lead to dysregulated ECS activity and subsequently to possible neuropsychiatric disorders, pharmacological intervention targeting the ECS is a promising therapeutic approach. Understanding the neurobiology of cannabinoid receptor signaling in depth will aid optimal design of therapeutic interventions, minimizing unwanted side effects.
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Affiliation(s)
- Beat Lutz
- Institute of Physiological Chemistry, University Medical Center of the Johannes Gutenberg University, Mainz, Germany
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55
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Morales P, Jagerovic N. Novel approaches and current challenges with targeting the endocannabinoid system. Expert Opin Drug Discov 2020; 15:917-930. [PMID: 32336154 PMCID: PMC7502221 DOI: 10.1080/17460441.2020.1752178] [Citation(s) in RCA: 22] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/11/2020] [Accepted: 04/02/2020] [Indexed: 12/12/2022]
Abstract
INTRODUCTION The pathophysiological relevance of the endocannabinoid system has been widely demonstrated in a variety of diseases including cancer, neurological disorders, and metabolic issues. Therefore, targeting the receptors and the endogenous machinery involved in this system can provide a successful therapeutic outcome. Ligands targeting the canonical cannabinoid receptors, CB1 and CB2, along with inhibitors of the endocannabinoid enzymes have been thoroughly studied in diverse disease models. In fact, phytocannabinoids such as cannabidiol or Δ9-tetrahydrocannabinol are currently on the market for the management of neuropathic pain due to spasticity in multiple sclerosis or seizures in children epilepsy amongst others. AREAS COVERED Challenges in the pharmacology of cannabinoids arise from its pharmacokinetics, off-target effects, and psychoactive effects. In this context, the current review outlines the novel molecular approaches emerging in the field discussing their clinical potential. EXPERT OPINION Even if orthosteric CB1 and CB2 ligands are on the forefront in cannabinoid clinical research, emerging strategies such as allosteric or biased modulation of these receptors along with controlled off-targets effects may increase the therapeutic potential of cannabinoids.
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Affiliation(s)
- Paula Morales
- Instituto de Química Médica, Consejo Superior de Investigaciones Científicas, Madrid, Spain
| | - Nadine Jagerovic
- Instituto de Química Médica, Consejo Superior de Investigaciones Científicas, Madrid, Spain
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56
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An D, Peigneur S, Hendrickx LA, Tytgat J. Targeting Cannabinoid Receptors: Current Status and Prospects of Natural Products. Int J Mol Sci 2020; 21:E5064. [PMID: 32709050 PMCID: PMC7404216 DOI: 10.3390/ijms21145064] [Citation(s) in RCA: 94] [Impact Index Per Article: 23.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/12/2020] [Revised: 07/14/2020] [Accepted: 07/15/2020] [Indexed: 02/07/2023] Open
Abstract
Cannabinoid receptors (CB1 and CB2), as part of the endocannabinoid system, play a critical role in numerous human physiological and pathological conditions. Thus, considerable efforts have been made to develop ligands for CB1 and CB2, resulting in hundreds of phyto- and synthetic cannabinoids which have shown varying affinities relevant for the treatment of various diseases. However, only a few of these ligands are clinically used. Recently, more detailed structural information for cannabinoid receptors was revealed thanks to the powerfulness of cryo-electron microscopy, which now can accelerate structure-based drug discovery. At the same time, novel peptide-type cannabinoids from animal sources have arrived at the scene, with their potential in vivo therapeutic effects in relation to cannabinoid receptors. From a natural products perspective, it is expected that more novel cannabinoids will be discovered and forecasted as promising drug leads from diverse natural sources and species, such as animal venoms which constitute a true pharmacopeia of toxins modulating diverse targets, including voltage- and ligand-gated ion channels, G protein-coupled receptors such as CB1 and CB2, with astonishing affinity and selectivity. Therefore, it is believed that discovering novel cannabinoids starting from studying the biodiversity of the species living on planet earth is an uncharted territory.
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Affiliation(s)
| | | | | | - Jan Tytgat
- Toxicology and Pharmacology, KU Leuven, Campus Gasthuisberg, O&N 2, Herestraat 49, P.O. Box 922, 3000 Leuven, Belgium; (D.A.); (S.P.); (L.A.H.)
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57
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Palomares B, Garrido-Rodriguez M, Gonzalo-Consuegra C, Gómez-Cañas M, Saen-Oon S, Soliva R, Collado JA, Fernández-Ruiz J, Morello G, Calzado MA, Appendino G, Muñoz E. Δ 9 -Tetrahydrocannabinolic acid alleviates collagen-induced arthritis: Role of PPARγ and CB 1 receptors. Br J Pharmacol 2020; 177:4034-4054. [PMID: 32510591 DOI: 10.1111/bph.15155] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/10/2019] [Revised: 05/22/2020] [Accepted: 05/27/2020] [Indexed: 02/06/2023] Open
Abstract
BACKGROUND AND PURPOSE Δ9 -Tetrahydrocannabinolic acid (Δ9 -THCA-A), the precursor of Δ9 -THC, is a non-psychotropic phytocannabinoid that shows PPARγ agonist activity. Here, we investigated the ability of Δ9 -THCA-A to modulate the classic cannabinoid CB1 and CB2 receptors and evaluated its anti-arthritis activity in vitro and in vivo. EXPERIMENTAL APPROACH Cannabinoid receptors binding and intrinsic activity, as well as their downstream signalling, were analysed in vitro and in silico. The anti-arthritis properties of Δ9 -THCA-A were studied in human chondrocytes and in the murine model of collagen-induced arthritis (CIA). Plasma disease biomarkers were identified by LC-MS/MS based on proteomic and elisa assays. KEY RESULTS Functional and docking analyses showed that Δ9 -THCA-A can act as an orthosteric CB1 receptor agonist and also as a positive allosteric modulator in the presence of CP-55,940. Also, Δ9 -THCA-A seemed to be an inverse agonist for CB2 receptors. In vivo, Δ9 -THCA-A reduced arthritis in CIA mice, preventing the infiltration of inflammatory cells, synovium hyperplasia, and cartilage damage. Furthermore, Δ9 -THCA-A inhibited expression of inflammatory and catabolic genes on knee joints. The anti-arthritic effect of Δ9 -THCA-A was blocked by either SR141716 or T0070907. Analysis of plasma biomarkers, and determination of cytokines and anti-collagen antibodies confirmed that Δ9 -THCA-A mediated its activity mainly through PPARγ and CB1 receptor pathways. CONCLUSION AND IMPLICATIONS Δ9 -THCA-A modulates CB1 receptors through the orthosteric and allosteric binding sites. In addition, Δ9 -THCA-A exerts anti-arthritis activity through CB1 receptors and PPARγ pathways, highlighting its potential for the treatment of chronic inflammatory diseases such as rheumatoid arthritis.
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Affiliation(s)
- Belén Palomares
- Maimonides Biomedical Research Institute of Córdoba, University of Córdoba, Córdoba, Spain.,Department of Cellular Biology, Physiology and Immunology, University of Córdoba, Córdoba, Spain.,Reina Sofía University Hospital, Córdoba, Spain
| | - Martín Garrido-Rodriguez
- Maimonides Biomedical Research Institute of Córdoba, University of Córdoba, Córdoba, Spain.,Department of Cellular Biology, Physiology and Immunology, University of Córdoba, Córdoba, Spain.,Reina Sofía University Hospital, Córdoba, Spain
| | - Claudia Gonzalo-Consuegra
- Instituto Universitario de Investigación en Neuroquímica, Departamento de Bioquímica y Biología Molecular, Facultad de Medicina, Universidad Complutense, Madrid, Spain.,Centro de Investigación Biomédica en Red de Enfermedades Neurodegenerativas (CIBERNED), Madrid, Spain.,Instituto Ramón y Cajal de Investigación Sanitaria (IRYCIS), Madrid, Spain
| | - María Gómez-Cañas
- Instituto Universitario de Investigación en Neuroquímica, Departamento de Bioquímica y Biología Molecular, Facultad de Medicina, Universidad Complutense, Madrid, Spain.,Centro de Investigación Biomédica en Red de Enfermedades Neurodegenerativas (CIBERNED), Madrid, Spain.,Instituto Ramón y Cajal de Investigación Sanitaria (IRYCIS), Madrid, Spain
| | | | | | | | - Javier Fernández-Ruiz
- Instituto Universitario de Investigación en Neuroquímica, Departamento de Bioquímica y Biología Molecular, Facultad de Medicina, Universidad Complutense, Madrid, Spain.,Centro de Investigación Biomédica en Red de Enfermedades Neurodegenerativas (CIBERNED), Madrid, Spain.,Instituto Ramón y Cajal de Investigación Sanitaria (IRYCIS), Madrid, Spain
| | | | - Marco A Calzado
- Maimonides Biomedical Research Institute of Córdoba, University of Córdoba, Córdoba, Spain.,Department of Cellular Biology, Physiology and Immunology, University of Córdoba, Córdoba, Spain.,Reina Sofía University Hospital, Córdoba, Spain
| | - Giovanni Appendino
- Dipartimento di Scienze del Farmaco, Università del Piemonte Orientale, Novara, Italy
| | - Eduardo Muñoz
- Maimonides Biomedical Research Institute of Córdoba, University of Córdoba, Córdoba, Spain.,Department of Cellular Biology, Physiology and Immunology, University of Córdoba, Córdoba, Spain.,Reina Sofía University Hospital, Córdoba, Spain
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58
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Abstract
A limited number of peripheral targets generate pain. Inflammatory mediators can sensitize these. The review addresses targets acting exclusively or predominantly on sensory neurons, mediators involved in inflammation targeting sensory neurons, and mediators involved in a more general inflammatory process, of which an analgesic effect secondary to an anti-inflammatory effect can be expected. Different approaches to address these systems are discussed, including scavenging proinflammatory mediators, applying anti-inflammatory mediators, and inhibiting proinflammatory or facilitating anti-inflammatory receptors. New approaches are contrasted to established ones; the current stage of progress is mentioned, in particular considering whether there is data from a molecular and cellular level, from animals, or from human trials, including an early stage after a market release. An overview of publication activity is presented, considering a IuPhar/BPS-curated list of targets with restriction to pain-related publications, which was also used to identify topics.
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Affiliation(s)
- Cosmin I Ciotu
- Center of Physiology and Pharmacology, Medical University of Vienna, Schwarzspanierstrasse 17, 1090, Vienna, Austria
| | - Michael J M Fischer
- Center of Physiology and Pharmacology, Medical University of Vienna, Schwarzspanierstrasse 17, 1090, Vienna, Austria.
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59
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Thomas A, Okine BN, Finn DP, Masocha W. Peripheral deficiency and antiallodynic effects of 2-arachidonoyl glycerol in a mouse model of paclitaxel-induced neuropathic pain. Biomed Pharmacother 2020; 129:110456. [PMID: 32603895 DOI: 10.1016/j.biopha.2020.110456] [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: 04/21/2020] [Revised: 06/16/2020] [Accepted: 06/23/2020] [Indexed: 12/12/2022] Open
Abstract
BACKGROUND Modulation of the endocannabinoid system has been shown to alleviate neuropathic pain. The aim of this study was to evaluate if treatment with paclitaxel, a chemotherapeutic agent that induces neuropathic pain, affects endocannabinoid levels at a time when mice develop paclitaxel-induced mechanical allodynia. We also evaluated the peripheral antiallodynic activity of the endocannabinoid 2-arachidonoyl glycerol (2-AG) and an inhibitor of monoacylglycerol lipase (MAGL), an enzyme responsible for 2-AG hydrolysis. METHODS Female BALB/c mice were treated intraperitoneally with paclitaxel to induce mechanical allodynia. Levels of the endocannabinoids, N-arachidonoylethanolamine (anandamide, AEA), 2-AG, and the N-acylethanolamines (NAEs), N-palmitoylethanolamide (PEA) and N-oleoylethanolamide (OEA), which are structurally-related to AEA, in the brain, spinal cord and paw skin were measured using LC-MS/MS. Protein expression of MAGL in the paw skin was measured using Wes™. The effects of subcutaneous (s.c.) injection of 2-AG and JZL184 (a MAGL inhibitor) into the right hind paw of mice with paclitaxel-induced mechanical allodynia were assessed using the dynamic plantar aesthesiometer. The effects of pretreatment, s.c., into the right hind paw, with cannabinoid type 1 (CB1) receptor antagonist AM251 and CB2 receptor antagonist AM630 on the antiallodynic effects of 2-AG were also evaluated. RESULTS The levels of 2-AG were reduced only in the paw skin of paclitaxel-treated mice, whilst the levels of AEA, PEA and OEA were not significantly altered. There was no change in the expression of MAGL in the paw skin. Administration of 2-AG and JZL184 produced antiallodynic effects against paclitaxel-induced mechanical allodynia in the injected right paw, but did not affect the uninjected left paw. The antiallodynic activity of 2-AG was antagonized by both AM251 and AM630. CONCLUSION These results indicate that during paclitaxel-induced mechanical allodynia there is a deficiency of 2-AG in the periphery, but not in the CNS. Increasing 2-AG in the paw by local administration of 2-AG or a MAGL inhibitor, alleviates mechanical allodynia in a CB1 and CB2 receptor-dependent manner.
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Affiliation(s)
- Amal Thomas
- Department of Pharmacology and Therapeutics, Faculty of Pharmacy, Kuwait University, Kuwait
| | - Bright N Okine
- Pharmacology and Therapeutics, School of Medicine, NCBES Centre for Pain Research and Galway Neuroscience Centre, National University of Ireland Galway, University Road, Galway, Ireland
| | - David P Finn
- Pharmacology and Therapeutics, School of Medicine, NCBES Centre for Pain Research and Galway Neuroscience Centre, National University of Ireland Galway, University Road, Galway, Ireland
| | - Willias Masocha
- Department of Pharmacology and Therapeutics, Faculty of Pharmacy, Kuwait University, Kuwait.
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60
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Allosteric modulators targeting cannabinoid cb1 and cb2 receptors: implications for drug discovery. Future Med Chem 2020; 11:2019-2037. [PMID: 31517528 DOI: 10.4155/fmc-2019-0005] [Citation(s) in RCA: 17] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/22/2022] Open
Abstract
Allosteric modulators of cannabinoid receptors hold great therapeutic potential, as they do not possess intrinsic efficacy, but instead enhance or diminish the receptor's response of orthosteric ligands allowing for the tempering of cannabinoid receptor signaling without the desensitization, tolerance and dependence. Allosteric modulators of cannabinoid receptors have numerous advantages over the orthosteric ligands such as higher receptor type selectivity, probe dependence and biased signaling, so they have a great potential to separate the therapeutic benefits from side effects own of orthosteric ligands. This review aims to give an overview of the CB1 and CB2 receptor allosteric modulators highlighting the structure-activity relationship and pharmacological profile of each classes, and their future promise.
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61
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Slivicki RA, Iyer V, Mali SS, Garai S, Thakur GA, Crystal JD, Hohmann AG. Positive Allosteric Modulation of CB 1 Cannabinoid Receptor Signaling Enhances Morphine Antinociception and Attenuates Morphine Tolerance Without Enhancing Morphine- Induced Dependence or Reward. Front Mol Neurosci 2020; 13:54. [PMID: 32410959 PMCID: PMC7199816 DOI: 10.3389/fnmol.2020.00054] [Citation(s) in RCA: 40] [Impact Index Per Article: 10.0] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/17/2019] [Accepted: 03/17/2020] [Indexed: 01/09/2023] Open
Abstract
Opioid analgesics represent a critical treatment for chronic pain in the analgesic ladder of the World Health Organization. However, their use can result in a number of unwanted side-effects including incomplete efficacy, constipation, physical dependence, and overdose liability. Cannabinoids enhance the pain-relieving effects of opioids in preclinical studies and dampen unwanted side-effects resulting from excessive opioid intake. We recently reported that a CB1 positive allosteric modulator (PAM) exhibits antinociceptive efficacy in models of pathological pain and lacks the adverse side effects of direct CB1 receptor activation. In the present study, we evaluated whether a CB1 PAM would enhance morphine’s therapeutic efficacy in an animal model of chemotherapy-induced neuropathic pain and characterized its impact on unwanted side-effects associated with chronic opioid administration. In paclitaxel-treated mice, both the CB1 PAM GAT211 and the opioid analgesic morphine reduced paclitaxel-induced behavioral hypersensitivities to mechanical and cold stimulation in a dose-dependent manner. Isobolographic analysis revealed that combinations of GAT211 and morphine resulted in anti-allodynic synergism. In paclitaxel-treated mice, a sub-threshold dose of GAT211 prevented the development of tolerance to the anti-allodynic effects of morphine over 20 days of once daily dosing. However, GAT211 did not reliably alter somatic withdrawal signs (i.e., jumps, paw tremors) in morphine-dependent neuropathic mice challenged with naloxone. In otherwise naïve mice, GAT211 also prolonged antinociceptive efficacy of morphine in the tail-flick test and reduced the overall right-ward shift in the ED50 for morphine to produce antinociception in the tail-flick test, consistent with attenuation of morphine tolerance. Pretreatment with GAT211 did not alter somatic signs of μ opioid receptor dependence in mice rendered dependent upon morphine via subcutaneous implantation of a morphine pellet. Moreover, GAT211 did not reliably alter μ-opioid receptor-mediated reward as measured by conditioned place preference to morphine. Our results suggest that a CB1 PAM may be beneficial in enhancing and prolonging the therapeutic properties of opioids while potentially sparing unwanted side-effects (e.g., tolerance) that occur with repeated opioid treatment.
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Affiliation(s)
- Richard A Slivicki
- Program in Neuroscience, Indiana University, Bloomington, IN, United States.,Department of Psychological and Brain Sciences, Indiana University, Bloomington, IN, United States
| | - Vishakh Iyer
- Program in Neuroscience, Indiana University, Bloomington, IN, United States.,Department of Psychological and Brain Sciences, Indiana University, Bloomington, IN, United States
| | - Sonali S Mali
- Department of Psychological and Brain Sciences, Indiana University, Bloomington, IN, United States
| | - Sumanta Garai
- Center for Drug Discovery, Bouve College of Health Sciences, Northeastern University, Boston, MA, United States
| | - Ganesh A Thakur
- Center for Drug Discovery, Bouve College of Health Sciences, Northeastern University, Boston, MA, United States
| | - Jonathon D Crystal
- Program in Neuroscience, Indiana University, Bloomington, IN, United States.,Department of Psychological and Brain Sciences, Indiana University, Bloomington, IN, United States
| | - Andrea G Hohmann
- Program in Neuroscience, Indiana University, Bloomington, IN, United States.,Department of Psychological and Brain Sciences, Indiana University, Bloomington, IN, United States.,Gill Center for Biomolecular Science, Indiana University, Bloomington, IN, United States
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62
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Stasiulewicz A, Znajdek K, Grudzień M, Pawiński T, Sulkowska JI. A Guide to Targeting the Endocannabinoid System in Drug Design. Int J Mol Sci 2020; 21:ijms21082778. [PMID: 32316328 PMCID: PMC7216112 DOI: 10.3390/ijms21082778] [Citation(s) in RCA: 70] [Impact Index Per Article: 17.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/16/2020] [Revised: 04/07/2020] [Accepted: 04/14/2020] [Indexed: 12/11/2022] Open
Abstract
The endocannabinoid system (ECS) is one of the most crucial systems in the human organism, exhibiting multi-purpose regulatory character. It is engaged in a vast array of physiological processes, including nociception, mood regulation, cognitive functions, neurogenesis and neuroprotection, appetite, lipid metabolism, as well as cell growth and proliferation. Thus, ECS proteins, including cannabinoid receptors and their endogenous ligands’ synthesizing and degrading enzymes, are promising therapeutic targets. Their modulation has been employed in or extensively studied as a treatment of multiple diseases. However, due to a complex nature of ECS and its crosstalk with other biological systems, the development of novel drugs turned out to be a challenging task. In this review, we summarize potential therapeutic applications for ECS-targeting drugs, especially focusing on promising synthetic compounds and preclinical studies. We put emphasis on modulation of specific proteins of ECS in different pathophysiological areas. In addition, we stress possible difficulties and risks and highlight proposed solutions. By presenting this review, we point out information pivotal in the spotlight of ECS-targeting drug design, as well as provide an overview of the current state of knowledge on ECS-related pharmacodynamics and show possible directions for needed research.
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Affiliation(s)
- Adam Stasiulewicz
- Department of Drug Chemistry, Faculty of Pharmacy, Medical University of Warsaw, Banacha 1, 02-097 Warsaw, Poland; (M.G.); (T.P.)
- Interdisciplinary Laboratory of Biological Systems Modelling, Centre of New Technologies, University of Warsaw, Banacha 2c, 02-097 Warsaw, Poland;
- Correspondence: (A.S.); (J.I.S.)
| | - Katarzyna Znajdek
- Interdisciplinary Laboratory of Biological Systems Modelling, Centre of New Technologies, University of Warsaw, Banacha 2c, 02-097 Warsaw, Poland;
- Faculty of Pharmacy, Medical University of Warsaw, Banacha 1, 02-097 Warsaw, Poland
| | - Monika Grudzień
- Department of Drug Chemistry, Faculty of Pharmacy, Medical University of Warsaw, Banacha 1, 02-097 Warsaw, Poland; (M.G.); (T.P.)
| | - Tomasz Pawiński
- Department of Drug Chemistry, Faculty of Pharmacy, Medical University of Warsaw, Banacha 1, 02-097 Warsaw, Poland; (M.G.); (T.P.)
| | - Joanna I. Sulkowska
- Interdisciplinary Laboratory of Biological Systems Modelling, Centre of New Technologies, University of Warsaw, Banacha 2c, 02-097 Warsaw, Poland;
- Faculty of Chemistry, University of Warsaw, Pasteura 1, 02-093 Warsaw, Poland
- Materials and Process Simulation Center, California Institute of Technology, Pasadena, CA 91125, USA
- Correspondence: (A.S.); (J.I.S.)
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Mustafa M, Donvito G, Moncayo L, Swafford A, Poklis J, Grauer R, Olszewska T, Ignatowska-Jankowska B, Kendall DA, Lu D, Lichtman AH. In vivo evaluation of the CB1 allosteric modulator LDK1258 reveals CB1-receptor independent behavioral effects. Pharmacol Biochem Behav 2020; 190:172840. [DOI: 10.1016/j.pbb.2019.172840] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 06/04/2019] [Revised: 11/24/2019] [Accepted: 12/21/2019] [Indexed: 01/25/2023]
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Hossain MZ, Ando H, Unno S, Kitagawa J. Targeting Peripherally Restricted Cannabinoid Receptor 1, Cannabinoid Receptor 2, and Endocannabinoid-Degrading Enzymes for the Treatment of Neuropathic Pain Including Neuropathic Orofacial Pain. Int J Mol Sci 2020; 21:E1423. [PMID: 32093166 PMCID: PMC7073137 DOI: 10.3390/ijms21041423] [Citation(s) in RCA: 25] [Impact Index Per Article: 6.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/15/2020] [Revised: 02/17/2020] [Accepted: 02/18/2020] [Indexed: 02/06/2023] Open
Abstract
Neuropathic pain conditions including neuropathic orofacial pain (NOP) are difficult to treat. Contemporary therapeutic agents for neuropathic pain are often ineffective in relieving pain and are associated with various adverse effects. Finding new options for treating neuropathic pain is a major priority in pain-related research. Cannabinoid-based therapeutic strategies have emerged as promising new options. Cannabinoids mainly act on cannabinoid 1 (CB1) and 2 (CB2) receptors, and the former is widely distributed in the brain. The therapeutic significance of cannabinoids is masked by their adverse effects including sedation, motor impairment, addiction and cognitive impairment, which are thought to be mediated by CB1 receptors in the brain. Alternative approaches have been developed to overcome this problem by selectively targeting CB2 receptors, peripherally restricted CB1 receptors and endocannabinoids that may be locally synthesized on demand at sites where their actions are pertinent. Many preclinical studies have reported that these strategies are effective for treating neuropathic pain and produce no or minimal side effects. Recently, we observed that inhibition of degradation of a major endocannabinoid, 2-arachydonoylglycerol, can attenuate NOP following trigeminal nerve injury in mice. This review will discuss the above-mentioned alternative approaches that show potential for treating neuropathic pain including NOP.
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Affiliation(s)
- Mohammad Zakir Hossain
- Department of Oral Physiology, School of Dentistry, Matsumoto Dental University, 1780 Gobara Hirooka, Shiojiri, Nagano 399-0781, Japan; (S.U.); (J.K.)
| | - Hiroshi Ando
- Department of Biology, School of Dentistry, Matsumoto Dental University, 1780 Gobara, Hirooka, Shiojiri, Nagano 399-0781, Japan;
| | - Shumpei Unno
- Department of Oral Physiology, School of Dentistry, Matsumoto Dental University, 1780 Gobara Hirooka, Shiojiri, Nagano 399-0781, Japan; (S.U.); (J.K.)
| | - Junichi Kitagawa
- Department of Oral Physiology, School of Dentistry, Matsumoto Dental University, 1780 Gobara Hirooka, Shiojiri, Nagano 399-0781, Japan; (S.U.); (J.K.)
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Prospéro-García O, Ruiz Contreras AE, Ortega Gómez A, Herrera-Solís A, Méndez-Díaz M. Endocannabinoids as Therapeutic Targets. Arch Med Res 2020; 50:518-526. [PMID: 32028095 DOI: 10.1016/j.arcmed.2019.09.005] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/30/2019] [Revised: 08/01/2019] [Accepted: 09/30/2019] [Indexed: 12/22/2022]
Abstract
Most of the drugs of abuse affect the brain by interacting with naturally expressed molecular receptors. Marihuana affects a series of receptors including cannabinoid receptor 1 (CB1R) and CB2R, among others. Endogenous molecules with cannabinoid activity interact with these receptors naturally. Receptors, ligands, synthesizing and degrading enzymes, as well as transporters, have been described. This endocannabinoid system modulates behaviors and physiological processes, i.e. food intake, the sleep-waking cycle, learning and memory, motivation, and pain perception, among others. The rather broad distribution of endocannabinoids in the brain explains the different effects marihuana induces in its users. However, this very same anatomical and physiological distribution makes this system a useful target for therapeutic endeavors. In this review, we briefly discuss the potential of small molecules that target the endocannabinoids as therapeutic tools to improve behaviors and treat illnesses. We believe that under medical supervision, endocannabinoid targets offer new advantages for patients for controlling multiple medical disorders.
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Affiliation(s)
- Oscar Prospéro-García
- Departamento de Fisiología, Laboratorio de Canabinoides, Facultad de Medicina, Universidad Nacional Autónoma de México, Ciudad de México, Mexico.
| | - Alejandra E Ruiz Contreras
- Laboratorio de Neurogenómica Cognitiva, Facultad de Psicología, Universidad Nacional Autónoma de México, Ciudad de México, Mexico
| | - Alette Ortega Gómez
- Laboratorio de Medicina Traslacional, Instituto Nacional de Cancerología, Ciudad de México, Mexico
| | - Andrea Herrera-Solís
- Laboratorio Efectos Terapéuticos de los Canabinoides, Subdirección de Investigación Biomédica, Hospital General Dr. Manuel Gea González, Ciudad de México, Mexico
| | - Mónica Méndez-Díaz
- Departamento de Fisiología, Laboratorio de Canabinoides, Facultad de Medicina, Universidad Nacional Autónoma de México, Ciudad de México, Mexico
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66
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Thapa D, Cairns EA, Szczesniak AM, Kulkarni PM, Straiker AJ, Thakur GA, Kelly MEM. Allosteric Cannabinoid Receptor 1 (CB1) Ligands Reduce Ocular Pain and Inflammation. Molecules 2020; 25:E417. [PMID: 31968549 PMCID: PMC7024337 DOI: 10.3390/molecules25020417] [Citation(s) in RCA: 26] [Impact Index Per Article: 6.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/18/2019] [Accepted: 01/16/2020] [Indexed: 01/08/2023] Open
Abstract
Cannabinoid receptor 1 (CB1) activation has been reported to reduce transient receptor potential cation channel subfamily V member 1 (TRPV1)-induced inflammatory responses and is anti-nociceptive and anti-inflammatory in corneal injury. We examined whether allosteric ligands, can modulate CB1 signaling to reduce pain and inflammation in corneal hyperalgesia. Corneal hyperalgesia was generated by chemical cauterization of cornea in wildtype and CB2 knockout (CB2-/-) mice. The novel racemic CB1 allosteric ligand GAT211 and its enantiomers GAT228 and GAT229 were examined alone or in combination with the orthosteric CB1 agonist Δ8-tetrahydrocannabinol (Δ8-THC). Pain responses were assessed following capsaicin (1 µM) stimulation of injured corneas at 6 h post-cauterization. Corneal neutrophil infiltration was also analyzed. GAT228, but not GAT229 or GAT211, reduced pain scores in response to capsaicin stimulation. Combination treatments of 0.5% GAT229 or 1% GAT211 with subthreshold Δ8-THC (0.4%) significantly reduced pain scores following capsaicin stimulation. The anti-nociceptive effects of both GAT229 and GAT228 were blocked with CB1 antagonist AM251, but remained unaffected in CB2-/- mice. Two percent GAT228, or the combination of 0.2% Δ8-THC with 0.5% GAT229 also significantly reduced corneal inflammation. CB1 allosteric ligands could offer a novel approach for treating corneal pain and inflammation.
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Affiliation(s)
- Dinesh Thapa
- Department of Pharmacology, Dalhousie University, Halifax, NS B3H 4R2, Canada
| | - Elizabeth A. Cairns
- Department of Pharmacology, Dalhousie University, Halifax, NS B3H 4R2, Canada
| | | | - Pushkar M. Kulkarni
- Department of Pharmaceutical Sciences, Northeastern University, Boston, MA 02115, USA
| | - Alex J. Straiker
- Department of Psychological and Brain Sciences, Indiana University, Bloomington, IN 47405, USA
| | - Ganesh A. Thakur
- Department of Pharmaceutical Sciences, Northeastern University, Boston, MA 02115, USA
| | - Melanie E. M. Kelly
- Department of Pharmacology, Dalhousie University, Halifax, NS B3H 4R2, Canada
- Department of Anesthesia, Pain Management & Perioperative Medicine, Dalhousie University, Halifax, NS B3H 4R2, Canada
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67
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Garai S, Kulkarni PM, Schaffer PC, Leo LM, Brandt AL, Zagzoog A, Black T, Lin X, Hurst DP, Janero DR, Abood ME, Zimmowitch A, Straiker A, Pertwee RG, Kelly M, Szczesniak AM, Denovan-Wright EM, Mackie K, Hohmann AG, Reggio PH, Laprairie RB, Thakur GA. Application of Fluorine- and Nitrogen-Walk Approaches: Defining the Structural and Functional Diversity of 2-Phenylindole Class of Cannabinoid 1 Receptor Positive Allosteric Modulators. J Med Chem 2020; 63:542-568. [PMID: 31756109 DOI: 10.1021/acs.jmedchem.9b01142] [Citation(s) in RCA: 34] [Impact Index Per Article: 8.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/02/2023]
Abstract
Cannabinoid 1 receptor (CB1R) allosteric ligands hold a far-reaching therapeutic promise. We report the application of fluoro- and nitrogen-walk approaches to enhance the drug-like properties of GAT211, a prototype CB1R allosteric agonist-positive allosteric modulator (ago-PAM). Several analogs exhibited improved functional potency (cAMP, β-arrestin 2), metabolic stability, and aqueous solubility. Two key analogs, GAT591 (6r) and GAT593 (6s), exhibited augmented allosteric-agonist and PAM activities in neuronal cultures, improved metabolic stability, and enhanced orthosteric agonist binding (CP55,940). Both analogs also exhibited good analgesic potency in the CFA inflammatory-pain model with longer duration of action over GAT211 while being devoid of adverse cannabimimetic effects. Another analog, GAT592 (9j), exhibited moderate ago-PAM potency and improved aqueous solubility with therapeutic reduction of intraocular pressure in murine glaucoma models. The SAR findings and the enhanced allosteric activity in this class of allosteric modulators were accounted for in our recently developed computational model for CB1R allosteric activation and positive allosteric modulation.
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Affiliation(s)
- Sumanta Garai
- Department of Pharmaceutical Sciences, School of Pharmacy, Bouvé College of Health Sciences , Northeastern University , Boston , Massachusetts 02115 , United States
| | - Pushkar M Kulkarni
- Department of Pharmaceutical Sciences, School of Pharmacy, Bouvé College of Health Sciences , Northeastern University , Boston , Massachusetts 02115 , United States
| | - Peter C Schaffer
- Department of Pharmaceutical Sciences, School of Pharmacy, Bouvé College of Health Sciences , Northeastern University , Boston , Massachusetts 02115 , United States
| | - Luciana M Leo
- Center for Substance Abuse Research, Lewis Katz School of Medicine , Temple University , Philadelphia , Pennsylvania 19140 , United States
| | - Asher L Brandt
- College of Pharmacy and Nutrition , University of Saskatchewan , 104 Clinic Pl , Saskatoon , SK S7N2Z4 , Canada
| | - Ayat Zagzoog
- College of Pharmacy and Nutrition , University of Saskatchewan , 104 Clinic Pl , Saskatoon , SK S7N2Z4 , Canada
| | - Tallan Black
- College of Pharmacy and Nutrition , University of Saskatchewan , 104 Clinic Pl , Saskatoon , SK S7N2Z4 , Canada
| | - Xiaoyan Lin
- Program in Neuroscience, Psychological and Brain Sciences, and Gill Center for Biomolecular Science , Indiana University , Bloomington , Indiana 47405 , United States
| | - Dow P Hurst
- Center for Drug Discovery , University of North Carolina Greensboro , Greensboro , North Carolina 27402 , United States
| | - David R Janero
- Department of Pharmaceutical Sciences, Bouvé College of Health Sciences, Department of Chemistry and Chemical Biology, College of Science, and Health Sciences Entrepreneurs , Northeastern University , Boston , Massachusetts 02115 , United States
| | - Mary E Abood
- Center for Substance Abuse Research, Lewis Katz School of Medicine , Temple University , Philadelphia , Pennsylvania 19140 , United States
| | - Anaelle Zimmowitch
- Program in Neuroscience, Psychological and Brain Sciences, and Gill Center for Biomolecular Science , Indiana University , Bloomington , Indiana 47405 , United States
| | - Alex Straiker
- Program in Neuroscience, Psychological and Brain Sciences, and Gill Center for Biomolecular Science , Indiana University , Bloomington , Indiana 47405 , United States
| | - Roger G Pertwee
- School of Medicine, Medical Sciences and Nutrition, Institute of Medical Sciences , University of Aberdeen , Aberdeen AB25 2ZD , Scotland, U.K
| | - Melanie Kelly
- Department of Pharmacology, Faculty of Medicine , Dalhousie University , 5850 College St , Halifax , NS , B3H4R2 , Canada
| | - Anna-Maria Szczesniak
- Department of Pharmacology, Faculty of Medicine , Dalhousie University , 5850 College St , Halifax , NS , B3H4R2 , Canada
| | - Eileen M Denovan-Wright
- Department of Pharmacology, Faculty of Medicine , Dalhousie University , 5850 College St , Halifax , NS , B3H4R2 , Canada
| | - Ken Mackie
- Program in Neuroscience, Psychological and Brain Sciences, and Gill Center for Biomolecular Science , Indiana University , Bloomington , Indiana 47405 , United States
| | - Andrea G Hohmann
- Program in Neuroscience, Psychological and Brain Sciences, and Gill Center for Biomolecular Science , Indiana University , Bloomington , Indiana 47405 , United States
| | - Patricia H Reggio
- Center for Drug Discovery , University of North Carolina Greensboro , Greensboro , North Carolina 27402 , United States
| | - Robert B Laprairie
- College of Pharmacy and Nutrition , University of Saskatchewan , 104 Clinic Pl , Saskatoon , SK S7N2Z4 , Canada.,Department of Pharmacology, Faculty of Medicine , Dalhousie University , 5850 College St , Halifax , NS , B3H4R2 , Canada
| | - Ganesh A Thakur
- Department of Pharmaceutical Sciences, School of Pharmacy, Bouvé College of Health Sciences , Northeastern University , Boston , Massachusetts 02115 , United States
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68
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Schurman LD, Lu D, Kendall DA, Howlett AC, Lichtman AH. Molecular Mechanism and Cannabinoid Pharmacology. Handb Exp Pharmacol 2020; 258:323-353. [PMID: 32236882 PMCID: PMC8637936 DOI: 10.1007/164_2019_298] [Citation(s) in RCA: 38] [Impact Index Per Article: 9.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/13/2022]
Abstract
Since antiquity, Cannabis has provoked enormous intrigue for its potential medicinal properties as well as for its unique pharmacological effects. The elucidation of its major cannabinoid constituents, Δ9-tetrahydrocannabinol (THC) and cannabidiol (CBD), led to the synthesis of new cannabinoids (termed synthetic cannabinoids) to understand the mechanisms underlying the pharmacology of Cannabis. These pharmacological tools were instrumental in the ultimate discovery of the endogenous cannabinoid system, which consists of CB1 and CB2 cannabinoid receptors and endogenously produced ligands (endocannabinoids), which bind and activate both cannabinoid receptors. CB1 receptors mediate the cannabimimetic effects of THC and are highly expressed on presynaptic neurons in the nervous system, where they modulate neurotransmitter release. In contrast, CB2 receptors are primarily expressed on immune cells. The endocannabinoids are tightly regulated by biosynthetic and hydrolytic enzymes. Accordingly, the endocannabinoid system plays a modulatory role in many physiological processes, thereby generating many promising therapeutic targets. An unintended consequence of this research was the emergence of synthetic cannabinoids sold for human consumption to circumvent federal laws banning Cannabis use. Here, we describe research that led to the discovery of the endogenous cannabinoid system and show how knowledge of this system benefitted as well as unintentionally harmed human health.
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Affiliation(s)
- Lesley D Schurman
- Department of Pharmacology and Toxicology, Virginia Commonwealth University, Richmond, VA, USA
| | - Dai Lu
- Rangel College of Pharmacy, Health Science Center, Texas A&M University, Kingsville, TX, USA
| | - Debra A Kendall
- Department of Pharmaceutical Sciences, University of Connecticut, Storrs, CT, USA
| | - Allyn C Howlett
- Department of Physiology and Pharmacology and Center for Research on Substance Use and Addiction, Wake Forest School of Medicine, Winston-Salem, NC, USA
| | - Aron H Lichtman
- Department of Pharmacology and Toxicology, Virginia Commonwealth University, Richmond, VA, USA.
- Department of Medicinal Chemistry, Virginia Commonwealth University, Richmond, VA, USA.
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69
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Allosteric Modulation of Cannabinoid Receptor 1-Current Challenges and Future Opportunities. Int J Mol Sci 2019; 20:ijms20235874. [PMID: 31771126 PMCID: PMC6928801 DOI: 10.3390/ijms20235874] [Citation(s) in RCA: 20] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/01/2019] [Revised: 11/19/2019] [Accepted: 11/20/2019] [Indexed: 02/07/2023] Open
Abstract
The cannabinoid receptor type 1 (CB1R), a G protein-coupled receptor (GPCR), plays an essential role in the control of many physiological processes such as hunger, memory loss, gastrointestinal activity, catalepsy, fear, depression, and chronic pain. Therefore, it is an attractive target for drug discovery to manage pain, neurodegenerative disorders, obesity, and substance abuse. However, the psychoactive adverse effects, generated by CB1R activation in the brain, limit the use of the orthosteric CB1R ligands as drugs. The discovery of CB1R allosteric modulators during the last decade provided new tools to target the CB1R. Moreover, application of the site-directed mutagenesis in combination with advanced physical methods, especially X-ray crystallography and computational modeling, has opened new horizons for understanding the complexity of the structure, function, and activity of cannabinoid receptors. In this paper, we present the latest advances in research on the CB1R, its allosteric modulation and allosteric ligands, and their translational potential. We focused on structural essentials of the cannabinoid 1 receptor- ligand (drug) interactions, as well as modes of CB1R signaling regulation.
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Laprairie RB, Mohamed KA, Zagzoog A, Kelly MEM, Stevenson LA, Pertwee R, Denovan-Wright EM, Thakur GA. Indomethacin Enhances Type 1 Cannabinoid Receptor Signaling. Front Mol Neurosci 2019; 12:257. [PMID: 31680861 PMCID: PMC6813218 DOI: 10.3389/fnmol.2019.00257] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/01/2019] [Accepted: 10/04/2019] [Indexed: 12/19/2022] Open
Abstract
In addition to its known actions as a non-selective cyclooxygenase (COX) 1 and 2 inhibitor, we hypothesized that indomethacin can act as an allosteric modulator of the type 1 cannabinoid receptor (CB1R) because of its shared structural features with the known allosteric modulators of CB1R. Indomethacin enhanced the binding of [3H]CP55940 to hCB1R and enhanced AEA-dependent [35S]GTPγS binding to hCB1R in Chinese hamster ovary (CHO) cell membranes. Indomethacin (1 μM) also enhanced CP55940-dependent βarrestin1 recruitment, cAMP inhibition, ERK1/2 and PLCβ3 phosphorylation in HEK293A cells expressing hCB1R, but not in cells expressing hCB2R. Finally, indomethacin enhanced the magnitude and duration of CP55940-induced hypolocomotion, immobility, hypothermia, and anti-nociception in C57BL/6J mice. Together, these data support the hypothesis that indomethacin acted as a positive allosteric modulator of hCB1R. The identification of structural and functional features shared amongst allosteric modulators of CB1R may lead to the development of novel compounds designed for greater CB1R or COX selectivity and compounds designed to modulate both the prostaglandin and endocannabinoid systems.
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Affiliation(s)
- Robert B Laprairie
- College of Pharmacy and Nutrition, University of Saskatchewan, Saskatoon, SK, Canada.,Department of Pharmacology, Dalhousie University, Halifax, NS, Canada
| | - Kawthar A Mohamed
- College of Pharmacy and Nutrition, University of Saskatchewan, Saskatoon, SK, Canada
| | - Ayat Zagzoog
- College of Pharmacy and Nutrition, University of Saskatchewan, Saskatoon, SK, Canada
| | - Melanie E M Kelly
- Department of Pharmacology, Dalhousie University, Halifax, NS, Canada.,Department of Ophthalmology and Visual Sciences, Dalhousie University, Halifax, NS, Canada
| | - Lesley A Stevenson
- School of Medical Sciences, The Institute of Medical Sciences, University of Aberdeen, Aberdeen, United Kingdom
| | - Roger Pertwee
- School of Medical Sciences, The Institute of Medical Sciences, University of Aberdeen, Aberdeen, United Kingdom
| | | | - Ganesh A Thakur
- Center for Drug Discovery, Department of Pharmaceutical Sciences, School of Pharmacy, Bouvé College of Health Sciences, Northeastern University, Boston, MA, United States
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71
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Slivicki RA, Mali SS, Hohmann AG. Voluntary exercise reduces both chemotherapy-induced neuropathic nociception and deficits in hippocampal cellular proliferation in a mouse model of paclitaxel-induced peripheral neuropathy. NEUROBIOLOGY OF PAIN 2019; 6:100035. [PMID: 31528755 PMCID: PMC6739464 DOI: 10.1016/j.ynpai.2019.100035] [Citation(s) in RCA: 15] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 05/06/2019] [Revised: 08/21/2019] [Accepted: 08/25/2019] [Indexed: 12/18/2022]
Abstract
Paclitaxel treatment did not alter voluntary running activity. Voluntary running reduced mechanical and cold allodynia induced by paclitaxel. Voluntary running reduced paclitaxel-induced deficits in hippocampal cellular proliferation.
Chemotherapy-induced peripheral neuropathy (CIPN) is a common dose-limiting side-effect of all major chemotherapeutic agents. Here, we explored efficacy of voluntary exercise as a nonpharmacological strategy for suppressing two distinct adverse side effects of chemotherapy treatment. We evaluated whether voluntary running would suppress both neuropathic pain and deficits in hippocampal cell proliferation in a mouse model of CIPN induced by the taxane chemotherapeutic agent paclitaxel. Mice were given free access to running wheels or were housed without running wheels during one of three different intervention phases: 1) during the onset (i.e. development phase) of paclitaxel-induced neuropathy, 2) prior to dosing with paclitaxel or its vehicle, or 3) following the establishment (i.e. maintenance phase) of paclitaxel-induced neuropathy. Paclitaxel treatment did not alter running wheel behavior relative to vehicle-treated animals in any study. Animals that engaged in voluntary running during the development phase of paclitaxel-induced neuropathy failed to display mechanical or cold hypersensitivities relative to sedentary control animals that did not have access to running wheels. A prior history of voluntary running delayed the onset of, but did not fully prevent, development of paclitaxel-induced neuropathic pain behavior. Voluntary running reduced already established mechanical and cold allodynia induced by paclitaxel. Importantly, voluntary running did not alter mechanical or cold responsivity in vehicle-treated animals, suggesting that the observed antinociceptive effect of exercise was dependent upon the presence of the pathological pain state. In the same animals evaluated for nociceptive responding, paclitaxel also reduced cellular proliferation but not cellular survival in the dentate gyrus of the hippocampus, as measured by immunohistochemistry for Ki67 and BrdU expression, respectively. Voluntary running abrogated paclitaxel-induced reductions in cellular proliferation to levels observed in vehicle-treated mice and also increased BrdU expression levels irrespective of chemotherapy treatment. Our studies support the hypothesis that voluntary exercise may be beneficial in suppressing both neuropathic pain and markers of hippocampal cellular function that are impacted by toxic challenge with chemotherapeutic agents.
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Affiliation(s)
- Richard A. Slivicki
- Program in Neuroscience, Indiana University, Bloomington, IN, United States
- Department of Psychological and Brain Sciences, Indiana University, Bloomington, IN, United States
| | - Sonali S. Mali
- Department of Psychological and Brain Sciences, Indiana University, Bloomington, IN, United States
| | - Andrea G. Hohmann
- Program in Neuroscience, Indiana University, Bloomington, IN, United States
- Department of Psychological and Brain Sciences, Indiana University, Bloomington, IN, United States
- Gill Center for Biomolecular Science, Indiana University, Bloomington, IN, United States
- Corresponding author at: Department of Psychological and Brain Sciences, Indiana University, 1101 E 10th Street, Bloomington, IN 47405-7007, United States.
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72
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Yu Y, Nguyen DT, Jiang J. G protein-coupled receptors in acquired epilepsy: Druggability and translatability. Prog Neurobiol 2019; 183:101682. [PMID: 31454545 DOI: 10.1016/j.pneurobio.2019.101682] [Citation(s) in RCA: 27] [Impact Index Per Article: 5.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/29/2019] [Revised: 07/09/2019] [Accepted: 08/15/2019] [Indexed: 02/06/2023]
Abstract
As the largest family of membrane proteins in the human genome, G protein-coupled receptors (GPCRs) constitute the targets of more than one-third of all modern medicinal drugs. In the central nervous system (CNS), widely distributed GPCRs in neuronal and nonneuronal cells mediate numerous essential physiological functions via regulating neurotransmission at the synapses. Whereas their abnormalities in expression and activity are involved in various neuropathological processes. CNS conditions thus remain highly represented among the indications of GPCR-targeted agents. Mounting evidence from a large number of animal studies suggests that GPCRs play important roles in the regulation of neuronal excitability associated with epilepsy, a common CNS disease afflicting approximately 1-2% of the population. Surprisingly, none of the US Food and Drug Administration (FDA)-approved (>30) antiepileptic drugs (AEDs) suppresses seizures through acting on GPCRs. This disparity raises concerns about the translatability of these preclinical findings and the druggability of GPCRs for seizure disorders. The currently available AEDs intervene seizures predominantly through targeting ion channels and have considerable limitations, as they often cause unbearable adverse effects, fail to control seizures in over 30% of patients, and merely provide symptomatic relief. Thus, identifying novel molecular targets for epilepsy is highly desired. Herein, we focus on recent progresses in understanding the comprehensive roles of several GPCR families in seizure generation and development of acquired epilepsy. We also dissect current hurdles hindering translational efforts in developing GPCRs as antiepileptic and/or antiepileptogenic targets and discuss the counteracting strategies that might lead to a potential cure for this debilitating CNS condition.
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Affiliation(s)
- Ying Yu
- Department of Pharmaceutical Sciences, College of Pharmacy, University of Tennessee Health Science Center, Memphis, TN 38163, USA; Drug Discovery Center, University of Tennessee Health Science Center, Memphis, TN 38163, USA
| | - Davis T Nguyen
- Department of Pharmaceutical Sciences, College of Pharmacy, University of Tennessee Health Science Center, Memphis, TN 38163, USA; Drug Discovery Center, University of Tennessee Health Science Center, Memphis, TN 38163, USA
| | - Jianxiong Jiang
- Department of Pharmaceutical Sciences, College of Pharmacy, University of Tennessee Health Science Center, Memphis, TN 38163, USA; Drug Discovery Center, University of Tennessee Health Science Center, Memphis, TN 38163, USA; Department of Anatomy and Neurobiology, College of Medicine, University of Tennessee Health Science Center, Memphis, TN 38163, USA; Neuroscience Institute, University of Tennessee Health Science Center, Memphis, TN 38163, USA.
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73
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Ribeiro JML, Filizola M. Insights From Molecular Dynamics Simulations of a Number of G-Protein Coupled Receptor Targets for the Treatment of Pain and Opioid Use Disorders. Front Mol Neurosci 2019; 12:207. [PMID: 31507375 PMCID: PMC6716474 DOI: 10.3389/fnmol.2019.00207] [Citation(s) in RCA: 13] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/31/2019] [Accepted: 08/07/2019] [Indexed: 01/20/2023] Open
Abstract
Effective treatments for pain management remain elusive due to the dangerous side-effects of current gold-standard opioid analgesics, including the respiratory depression that has led to skyrocketing death rates from opioid overdoses over the past decade. In an attempt to address the horrific opioid crisis worldwide, the National Institute on Drug Abuse has recently proposed boosting research on specific pharmacological mechanisms mediated by a number of G protein-coupled receptors (GPCRs). This research is expected to expedite the discovery of medications for opioid overdose and opioid use disorders, leading toward a safer and more effective treatment of pain. Here, we review mechanistic insights from recent all-atom molecular dynamics simulations of a specific subset of GPCRs for which high-resolution experimental structures are available, including opioid, cannabinoid, orexin, metabotropic glutamate, and dopamine receptor subtypes.
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Affiliation(s)
- João Marcelo Lamim Ribeiro
- Department of Pharmacological Sciences, Icahn School of Medicine at Mount Sinai, New York, NY, United States
| | - Marta Filizola
- Department of Pharmacological Sciences, Icahn School of Medicine at Mount Sinai, New York, NY, United States
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74
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Hurst DP, Garai S, Kulkarni PM, Schaffer PC, Reggio PH, Thakur GA. Identification of CB1 Receptor Allosteric Sites Using Force-Biased MMC Simulated Annealing and Validation by Structure-Activity Relationship Studies. ACS Med Chem Lett 2019; 10:1216-1221. [PMID: 31413808 DOI: 10.1021/acsmedchemlett.9b00256] [Citation(s) in RCA: 20] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/10/2019] [Accepted: 07/10/2019] [Indexed: 02/02/2023] Open
Abstract
Positive allosteric modulation of the cannabinoid 1 receptor (CB1R) has demonstrated distinct therapeutic advantages that address several limitations associated with orthosteric agonism and has opened a promising therapeutic avenue for further drug development. To advance the development of CB1R positive allosteric modulators, it is important to understand the molecular architecture of CB1R allosteric site(s). The goal of this work was to use Force-Biased MMC Simulated Annealing to identify binding sites for GAT228 (R), a partial allosteric agonist, and GAT229 (S), a positive allosteric modulator (PAM) at the CB1R. Our studies suggest that GAT228 binds in an intracellular (IC) TMH1-2-4 exosite that would allow this compound to act as a CB1 allosteric agonist as well as a CB1 PAM. In contrast, GAT229 binds at the extracellular (EC) ends of TMH2/3, just beneath the EC1 loop. At this site, this compound can act as CB1 PAM only. Finally, these results were successfully validated through the synthesis and biochemical evaluation of a focused library of compounds.
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Affiliation(s)
- Dow P. Hurst
- Department of Chemistry and Biochemistry, University of North Carolina at Greensboro, Greensboro North Carolina 27412, United States
| | - Sumanta Garai
- Department of Pharmaceutical Sciences, Bouvé College of Health Sciences, Northeastern University, Boston, Massachusetts 02115, United States
| | - Pushkar M. Kulkarni
- Department of Pharmaceutical Sciences, Bouvé College of Health Sciences, Northeastern University, Boston, Massachusetts 02115, United States
| | - Peter C. Schaffer
- Department of Pharmaceutical Sciences, Bouvé College of Health Sciences, Northeastern University, Boston, Massachusetts 02115, United States
| | - Patricia H. Reggio
- Department of Chemistry and Biochemistry, University of North Carolina at Greensboro, Greensboro North Carolina 27412, United States
| | - Ganesh A. Thakur
- Department of Pharmaceutical Sciences, Bouvé College of Health Sciences, Northeastern University, Boston, Massachusetts 02115, United States
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75
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Laprairie RB, Bagher AM, Rourke JL, Zrein A, Cairns EA, Kelly MEM, Sinal CJ, Kulkarni PM, Thakur GA, Denovan-Wright EM. Positive allosteric modulation of the type 1 cannabinoid receptor reduces the signs and symptoms of Huntington's disease in the R6/2 mouse model. Neuropharmacology 2019; 151:1-12. [PMID: 30940536 DOI: 10.1016/j.neuropharm.2019.03.033] [Citation(s) in RCA: 32] [Impact Index Per Article: 6.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/29/2018] [Revised: 03/26/2019] [Accepted: 03/27/2019] [Indexed: 12/18/2022]
Abstract
Huntington's disease (HD) is an inherited progressive neurodegenerative disease characterized by motor, cognitive, and behavioural changes. One of the earliest changes to occur in HD is a reduction in cannabinoid 1 receptor (CB1) levels in the striatum, which is strongly correlated with HD pathogenesis. CB1 positive allosteric modulators (PAM) enhance receptor affinity for, and efficacy of activation by, orthosteric ligands, including the endocannabinoids anandamide and 2-arachidonoylglycerol. The goal of this study was to determine whether the recently characterized CB1 allosteric modulators GAT211 (racemic), GAT228 (R-enantiomer), and GAT229 (S-enantiomer), affected the signs and symptoms of HD. GAT211, GAT228, and GAT229 were evaluated in normal and HD cell models, and in a transgenic mouse model of HD (7-week-old male R6/2 mice, 10 mg/kg/d, 21 d, i.p.). GAT229 was a CB1 PAM that improved cell viability in HD cells and improved motor coordination, delayed symptom onset, and normalized gene expression in R6/2 HD mice. GAT228 was an allosteric agonist that did not enhance endocannabinoid signaling or change symptom progression in R6/2 mice. GAT211 displayed intermediate effects between its enantiomers. The compounds used here are not drugs, but probe compounds used to determine the potential utility of CB1 PAMs in HD. Changes in gene expression, and not protein, were quantified in R6/2 HD mice because HD pathogenesis is associated with dysregulation of mRNA levels. The data presented here provide the first proof of principle for the use of CB1 PAMs to treat the signs and symptoms of HD.
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Affiliation(s)
- Robert B Laprairie
- College of Pharmacy and Nutrition, University of Saskatchewan, Canada; Department of Pharmacology, Dalhousie University, Canada
| | - Amina M Bagher
- Department of Pharmacology and Toxicology, Faculty of Pharmacy, King AbdulAziz University,Saudi Arabia; Department of Pharmacology, Dalhousie University, Canada
| | - Jillian L Rourke
- Department of Pharmacology, Dalhousie University, Canada; Department of Chemistry & Biochemistry, Mount Allison University, Canada
| | - Adel Zrein
- Department of Pharmacology, Dalhousie University, Canada
| | | | - Melanie E M Kelly
- Department of Pharmacology, Dalhousie University, Canada; Department of Ophthalmology and Visual Sciences, Dalhousie University, Canada
| | | | - Pushkar M Kulkarni
- Center for Drug Discovery, Department of Pharmaceutical Sciences, School of Pharmacy, Bouvé College of Health Sciences, Northeastern University, USA
| | - Ganesh A Thakur
- Center for Drug Discovery, Department of Pharmaceutical Sciences, School of Pharmacy, Bouvé College of Health Sciences, Northeastern University, USA
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76
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Lu D, Immadi SS, Wu Z, Kendall DA. Translational potential of allosteric modulators targeting the cannabinoid CB 1 receptor. Acta Pharmacol Sin 2019; 40:324-335. [PMID: 30333554 PMCID: PMC6460365 DOI: 10.1038/s41401-018-0164-x] [Citation(s) in RCA: 25] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/13/2018] [Accepted: 08/27/2018] [Indexed: 12/11/2022] Open
Abstract
The cannabinoid type-1 (CB1) receptor, a G-protein-coupled receptor, is an attractive target for drug discovery due to its involvement in many physiological processes. Historically, drug discovery efforts targeting the CB1 receptor have focused on the development of orthosteric ligands that interact with the active site to which endogenous cannabinoids bind. Research performed over the last several decades has revealed substantial difficulties in translating CB1 orthosteric ligands into druggable candidates. The difficulty is mainly due to the adverse effects associated with orthosteric CB1 ligands. Recent discoveries of allosteric CB1 modulators provide tremendous opportunities to develop CB1 ligands with novel mechanisms of action; these ligands may potentially improve the pharmacological effects and enhance drug safety in treating the disorders by regulating the functions of the CB1 receptor. In this paper, we review and summarize the complex pharmacological profiles of each class of CB1 allosteric modulators, the development of new classes of CB1 allosteric modulators and the results from in vivo assessments of their therapeutic value.
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Affiliation(s)
- Dai Lu
- Rangel College of Pharmacy, Texas A&M University, Kingsville, TX, 78363, USA.
| | - Sri Sujana Immadi
- Rangel College of Pharmacy, Texas A&M University, Kingsville, TX, 78363, USA
| | - Zhixing Wu
- Rangel College of Pharmacy, Texas A&M University, Kingsville, TX, 78363, USA
| | - Debra A Kendall
- Department of Pharmaceutical Sciences, University of Connecticut, Storrs, CT, 06269, USA
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Brain permeant and impermeant inhibitors of fatty-acid amide hydrolase suppress the development and maintenance of paclitaxel-induced neuropathic pain without producing tolerance or physical dependence in vivo and synergize with paclitaxel to reduce tumor cell line viability in vitro. Pharmacol Res 2019; 142:267-282. [PMID: 30739035 DOI: 10.1016/j.phrs.2019.02.002] [Citation(s) in RCA: 15] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 08/24/2018] [Revised: 12/22/2018] [Accepted: 02/01/2019] [Indexed: 12/19/2022]
Abstract
Activation of cannabinoid CB1 receptors suppresses pathological pain but also produces unwanted side effects, including tolerance and physical dependence. Inhibition of fatty-acid amide hydrolase (FAAH), the major enzyme catalyzing the degradation of anandamide (AEA), an endocannabinoid, and other fatty-acid amides, suppresses pain without unwanted side effects typical of direct CB1 agonists. However, FAAH inhibitors have failed to show efficacy in several clinical trials suggesting that the right partnership of FAAH inhibition and pathology has yet to be identified. We compared efficacy of chronic treatments with a centrally penetrant FAAH inhibitor (URB597), a peripherally restricted FAAH inhibitor (URB937) and an orthosteric pan-cannabinoid agonist (WIN55,212-2) in suppressing neuropathic pain induced by the chemotherapeutic agent paclitaxel. Each FAAH inhibitor suppressed the development of paclitaxel-induced neuropathic pain and reduced the maintenance of already established allodynia with sustained efficacy. Tolerance developed to the anti-allodynic efficacy of WIN55,212-2, but not to that of URB597 or URB937, in each dosing paradigm. Challenge with the CB1 antagonist rimonabant precipitated CB1-dependent withdrawal in paclitaxel-treated mice receiving WIN55,212-2 but not URB597 or URB937. When dosing with either URB597 or URB937 was restricted to the development of neuropathy, paclitaxel-induced allodynia emerged following termination of drug delivery. These observations suggest that both FAAH inhibitors were anti-allodynic rather than curative. Moreover, neither URB597 nor URB937 impeded the ability of paclitaxel to reduce breast (4T1) or ovarian (HeyA8) tumor cell line viability. In fact, URB597 and URB937 alone reduced 4T1 tumor cell line viability, albeit with low potency, and the dose matrix of each combination with paclitaxel was synergistic in reducing 4T1 and HeyA8 tumor cell line viability according to Bliss, Highest Single Agent (HSA) and Loewe additivity models. Both FAAH inhibitors synergized with paclitaxel to reduce 4T1 and HeyA8 tumor cell line viability without reducing viability of non-tumor HEK293 cells. Neither FAAH inhibitor reduced viability of non-tumor HEK293 cells in either the presence or absence of paclitaxel, suggesting that nonspecific cytotoxic effects were not produced by the same treatments. Our results suggest that FAAH inhibitors reduce paclitaxel-induced allodynia without the occurrence of CB1-dependence in vivo and may, in fact, enhance the anti-tumor actions of paclitaxel in vitro.
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Trexler KR, Eckard ML, Kinsey SG. CB 1 positive allosteric modulation attenuates Δ 9-THC withdrawal and NSAID-induced gastric inflammation. Pharmacol Biochem Behav 2019; 177:27-33. [PMID: 30597181 PMCID: PMC6405226 DOI: 10.1016/j.pbb.2018.12.009] [Citation(s) in RCA: 16] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 10/10/2018] [Revised: 12/06/2018] [Accepted: 12/27/2018] [Indexed: 02/07/2023]
Abstract
Recently, multiple compounds have been synthesized that target the allosteric binding site(s) of CB1. These CB1 positive allosteric modulators may capture the benefits of cannabinoid receptor activation without unwanted psychoactive effects, such as sedation. For example, ZCZ011 blocks neuropathic pain, absent the catalepsy, sedation, and hypothermia caused by CB1 orthosteric modulators, including Δ9-tetrahydrocannabinol (THC). The primary goal of the present study was to evaluate the potential of ZCZ011 to attenuate somatic signs of cannabinoid withdrawal in mice. Mice were repeatedly administered THC (10 mg/kg, s.c.) or vehicle, and withdrawal was either precipitated using the CB1 antagonist rimonabant (3 mg/kg, i.p.) or elicited spontaneously via THC abstinence. ZCZ011 (≥10 mg/kg, i.p.) significantly attenuated somatic signs of withdrawal, including head twitches and paw tremors, but had no effect on locomotor activity or conditioned place preference. We next tested the antiulcerogenic properties of CB1 positive allosteric modulation. Mice were fasted for 22 h, administered ZCZ011, and gastric hemorrhages were induced with the nonsteroidal anti-inflammatory drug diclofenac sodium (100 mg/kg, p.o.). ZCZ011 alone had no effect on gastric ulceration, but ZCZ011 (≥10 mg/kg) blocked ulcer formation when combined with a subthreshold MAGL inhibitor (JZL184; 1 mg/kg, i.p.). Thus, CB1 positive allosteric modulation is a novel approach to treat cannabinoid dependence and gastric inflammation.
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Affiliation(s)
- K R Trexler
- Department of Psychology, West Virginia University, Morgantown, WV, USA
| | - M L Eckard
- Department of Psychology, West Virginia University, Morgantown, WV, USA
| | - S G Kinsey
- Department of Psychology, West Virginia University, Morgantown, WV, USA; Department of Neuroscience, West Virginia University, Morgantown, WV, USA.
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79
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De Aquino JP, Ross DA. Cannabinoids and Pain: Weeding Out Undesired Effects With a Novel Approach to Analgesia. Biol Psychiatry 2018; 84:e67-e69. [PMID: 30360776 PMCID: PMC6697049 DOI: 10.1016/j.biopsych.2018.09.003] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 08/28/2018] [Revised: 09/11/2018] [Accepted: 09/11/2018] [Indexed: 01/27/2023]
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80
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The Contribution of Endogenous Modulatory Systems to TMS- and tDCS-Induced Analgesia: Evidence from PET Studies. Pain Res Manag 2018; 2018:2368386. [PMID: 30538794 PMCID: PMC6257907 DOI: 10.1155/2018/2368386] [Citation(s) in RCA: 23] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/20/2018] [Revised: 07/23/2018] [Accepted: 09/25/2018] [Indexed: 12/17/2022]
Abstract
Chronic pain is an important public health issue. Moreover, its adequate management is still considered a major clinical problem, mainly due to its incredible complexity and still poorly understood pathophysiology. Recent scientific evidence coming from neuroimaging research, particularly functional magnetic resonance (fMRI) and positron emission tomography (PET) studies, indicates that chronic pain is associated with structural and functional changes in several brain structures that integrate antinociceptive pathways and endogenous modulatory systems. Furthermore, the last two decades have witnessed a huge increase in the number of studies evaluating the clinical effects of noninvasive neuromodulatory methods, especially transcranial magnetic stimulation (TMS) and transcranial direct current stimulation (tDCS), which have been proved to effectively modulate the cortical excitability, resulting in satisfactory analgesic effects with minimal adverse events. Nevertheless, the precise neuromechanisms whereby such methods provide pain control are still largely unexplored. Recent studies have brought valuable information regarding the recruitment of different modulatory systems and related neurotransmitters, including glutamate, dopamine, and endogenous opioids. However, the specific neurocircuits involved in the analgesia produced by those therapies have not been fully elucidated. This review focuses on the current literature correlating the clinical effects of noninvasive methods of brain stimulation to the changes in the activity of endogenous modulatory systems.
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81
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Vučković S, Srebro D, Vujović KS, Vučetić Č, Prostran M. Cannabinoids and Pain: New Insights From Old Molecules. Front Pharmacol 2018; 9:1259. [PMID: 30542280 PMCID: PMC6277878 DOI: 10.3389/fphar.2018.01259] [Citation(s) in RCA: 173] [Impact Index Per Article: 28.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/27/2018] [Accepted: 10/15/2018] [Indexed: 01/11/2023] Open
Abstract
Cannabis has been used for medicinal purposes for thousands of years. The prohibition of cannabis in the middle of the 20th century has arrested cannabis research. In recent years there is a growing debate about the use of cannabis for medical purposes. The term ‘medical cannabis’ refers to physician-recommended use of the cannabis plant and its components, called cannabinoids, to treat disease or improve symptoms. Chronic pain is the most commonly cited reason for using medical cannabis. Cannabinoids act via cannabinoid receptors, but they also affect the activities of many other receptors, ion channels and enzymes. Preclinical studies in animals using both pharmacological and genetic approaches have increased our understanding of the mechanisms of cannabinoid-induced analgesia and provided therapeutical strategies for treating pain in humans. The mechanisms of the analgesic effect of cannabinoids include inhibition of the release of neurotransmitters and neuropeptides from presynaptic nerve endings, modulation of postsynaptic neuron excitability, activation of descending inhibitory pain pathways, and reduction of neural inflammation. Recent meta-analyses of clinical trials that have examined the use of medical cannabis in chronic pain present a moderate amount of evidence that cannabis/cannabinoids exhibit analgesic activity, especially in neuropathic pain. The main limitations of these studies are short treatment duration, small numbers of patients, heterogeneous patient populations, examination of different cannabinoids, different doses, the use of different efficacy endpoints, as well as modest observable effects. Adverse effects in the short-term medical use of cannabis are generally mild to moderate, well tolerated and transient. However, there are scant data regarding the long-term safety of medical cannabis use. Larger well-designed studies of longer duration are mandatory to determine the long-term efficacy and long-term safety of cannabis/cannabinoids and to provide definitive answers to physicians and patients regarding the risk and benefits of its use in the treatment of pain. In conclusion, the evidence from current research supports the use of medical cannabis in the treatment of chronic pain in adults. Careful follow-up and monitoring of patients using cannabis/cannabinoids are mandatory.
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Affiliation(s)
- Sonja Vučković
- Department of Pharmacology, Clinical Pharmacology and Toxicology, Faculty of Medicine, University of Belgrade, Belgrade, Serbia
| | - Dragana Srebro
- Department of Pharmacology, Clinical Pharmacology and Toxicology, Faculty of Medicine, University of Belgrade, Belgrade, Serbia
| | - Katarina Savić Vujović
- Department of Pharmacology, Clinical Pharmacology and Toxicology, Faculty of Medicine, University of Belgrade, Belgrade, Serbia
| | - Čedomir Vučetić
- Clinic of Orthopaedic Surgery and Traumatology, Clinical Center of Serbia, Belgrade, Serbia.,Faculty of Medicine, University of Belgrade, Belgrade, Serbia
| | - Milica Prostran
- Department of Pharmacology, Clinical Pharmacology and Toxicology, Faculty of Medicine, University of Belgrade, Belgrade, Serbia
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Slivicki RA, Saberi SA, Iyer V, Vemuri VK, Makriyannis A, Hohmann AG. Brain-Permeant and -Impermeant Inhibitors of Fatty Acid Amide Hydrolase Synergize with the Opioid Analgesic Morphine to Suppress Chemotherapy-Induced Neuropathic Nociception Without Enhancing Effects of Morphine on Gastrointestinal Transit. J Pharmacol Exp Ther 2018; 367:551-563. [PMID: 30275151 DOI: 10.1124/jpet.118.252288] [Citation(s) in RCA: 27] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/26/2018] [Accepted: 09/28/2018] [Indexed: 01/15/2023] Open
Abstract
Opioid-based therapies remain a mainstay for chronic pain management, but unwanted side effects limit therapeutic use. We compared efficacies of brain-permeant and -impermeant inhibitors of fatty acid amide hydrolase (FAAH) in suppressing neuropathic pain induced by the chemotherapeutic agent paclitaxel. Paclitaxel produced mechanical and cold allodynia without altering nestlet shredding or marble burying behaviors. We compared FAAH inhibitors that differ in their ability to penetrate the central nervous system for antiallodynic efficacy, pharmacological specificity, and synergism with the opioid analgesic morphine. (3'-(aminocarbonyl)[1,1'-biphenyl]- 3-yl)-cyclohexylcarbamate (URB597), a brain-permeant FAAH inhibitor, attenuated paclitaxel-induced allodynia via cannabinoid receptor 1 (CB1) and cannabinoid receptor 2 (CB2) mechanisms. URB937, a brain-impermeant FAAH inhibitor, suppressed paclitaxel-induced allodynia through a CB1 mechanism only. 5-[4-(4-cyano-1-butyn-1-yl)phenyl]-1-(2,4-dichlorophenyl)-N-(1,1-dioxido-4-thiomorpholinyl)-4-methyl-1H-pyrazole-3-carboxamide (AM6545), a peripherally restricted CB1 antagonist, fully reversed the antiallodynic efficacy of N-cyclohexyl-carbamic acid, 3'-(aminocarbonyl)-6-hydroxy[1,1'- biphenyl]-3-yl ester (URB937) but only partially reversed that of URB597. Thus, URB937 suppressed paclitaxel-induced allodynia through a mechanism that was dependent upon peripheral CB1 receptor activation only. Antiallodynic effects of both FAAH inhibitors were reversed by N-(piperidin-1-yl)-5-(4-iodophenyl)-1-(2,4-dichlorophenyl)-4-methyl-1H-pyrazole-3-carboxamide (AM251). Antiallodynic effects of URB597, but not URB937, were reversed by 6-iodo-2-methyl-1-[2-(4-morpholinyl)ethyl]-1H-indol-3-yl](4-methoxyphenyl)methanone (AM630). Isobolographic analysis revealed synergistic interactions between morphine and either URB597 or URB937 in reducing paclitaxel-induced allodynia. A leftward shift in the dose-response curve of morphine antinociception was observed when morphine was coadministered with either URB597 or URB937, consistent with morphine sparing. However, neither URB937 nor URB597 enhanced morphine-induced deficits in colonic transit. Thus, our findings suggest that FAAH inhibition may represent a therapeutic avenue to reduce the overall amount of opioid needed for treating neuropathic pain with potential to reduce unwanted side effects that accompany opioid administration.
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Affiliation(s)
- Richard A Slivicki
- Program in Neuroscience (R.A.S., V.I., A.G.H.), Department of Psychological and Brain Sciences (R.A.S., S.A.S., V.I., A.G.H.), and Gill Center for Biomolecular Science (A.G.H.), Indiana University, Bloomington, Indiana; and Center for Drug Discovery, Northeastern University, Boston, Massachusetts (V.K.V., A.M.)
| | - Shahin A Saberi
- Program in Neuroscience (R.A.S., V.I., A.G.H.), Department of Psychological and Brain Sciences (R.A.S., S.A.S., V.I., A.G.H.), and Gill Center for Biomolecular Science (A.G.H.), Indiana University, Bloomington, Indiana; and Center for Drug Discovery, Northeastern University, Boston, Massachusetts (V.K.V., A.M.)
| | - Vishakh Iyer
- Program in Neuroscience (R.A.S., V.I., A.G.H.), Department of Psychological and Brain Sciences (R.A.S., S.A.S., V.I., A.G.H.), and Gill Center for Biomolecular Science (A.G.H.), Indiana University, Bloomington, Indiana; and Center for Drug Discovery, Northeastern University, Boston, Massachusetts (V.K.V., A.M.)
| | - V Kiran Vemuri
- Program in Neuroscience (R.A.S., V.I., A.G.H.), Department of Psychological and Brain Sciences (R.A.S., S.A.S., V.I., A.G.H.), and Gill Center for Biomolecular Science (A.G.H.), Indiana University, Bloomington, Indiana; and Center for Drug Discovery, Northeastern University, Boston, Massachusetts (V.K.V., A.M.)
| | - Alexandros Makriyannis
- Program in Neuroscience (R.A.S., V.I., A.G.H.), Department of Psychological and Brain Sciences (R.A.S., S.A.S., V.I., A.G.H.), and Gill Center for Biomolecular Science (A.G.H.), Indiana University, Bloomington, Indiana; and Center for Drug Discovery, Northeastern University, Boston, Massachusetts (V.K.V., A.M.)
| | - Andrea G Hohmann
- Program in Neuroscience (R.A.S., V.I., A.G.H.), Department of Psychological and Brain Sciences (R.A.S., S.A.S., V.I., A.G.H.), and Gill Center for Biomolecular Science (A.G.H.), Indiana University, Bloomington, Indiana; and Center for Drug Discovery, Northeastern University, Boston, Massachusetts (V.K.V., A.M.)
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83
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Di Marzo V. New approaches and challenges to targeting the endocannabinoid system. Nat Rev Drug Discov 2018; 17:623-639. [DOI: 10.1038/nrd.2018.115] [Citation(s) in RCA: 256] [Impact Index Per Article: 42.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/11/2022]
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84
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Tham M, Yilmaz O, Alaverdashvili M, Kelly MEM, Denovan-Wright EM, Laprairie RB. Allosteric and orthosteric pharmacology of cannabidiol and cannabidiol-dimethylheptyl at the type 1 and type 2 cannabinoid receptors. Br J Pharmacol 2018; 176:1455-1469. [PMID: 29981240 DOI: 10.1111/bph.14440] [Citation(s) in RCA: 185] [Impact Index Per Article: 30.8] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/06/2017] [Revised: 06/15/2018] [Accepted: 06/26/2018] [Indexed: 12/14/2022] Open
Abstract
BACKGROUND AND PURPOSE We sought to understand why (-)-cannabidiol (CBD) and (-)-cannabidiol-dimethylheptyl (CBD-DMH) exhibit distinct pharmacology, despite near identical structures. EXPERIMENTAL APPROACH HEK293A cells expressing either human type 1 cannabinoid (CB1 ) receptors or CB2 receptors were treated with CBD or CBD-DMH with or without the CB1 and CB2 receptor agonist CP55,940, CB1 receptor allosteric modulator Org27569 or CB2 receptor inverse agonist SR144528. Ligand binding, cAMP levels and βarrestin1 recruitment were measured. CBD and CBD-DMH binding was simulated with models of human CB1 or CB2 receptors, based on the recently published crystal structures of agonist-bound (5XRA) or antagonist-bound (5TGZ) human CB1 receptors. KEY RESULTS At CB1 receptors, CBD was a negative allosteric modulator (NAM), and CBD-DMH was a mixed agonist/positive allosteric modulator. CBD and Org27569 shared multiple interacting residues in the antagonist-bound model of CB1 receptors (5TGZ) but shared a binding site with CP55,940 in the agonist-bound model of CB1 receptors (5XRA). The binding site for CBD-DMH in the CB1 receptor models overlapped with CP55,940 and Org27569. At CB2 receptors, CBD was a partial agonist, and CBD-DMH was a positive allosteric modulator of cAMP modulation but a NAM of βarrestin1 recruitment. CBD, CP55,940 and SR144528 shared a binding site in the CB2 receptor models that was separate from CBD-DMH. CONCLUSION AND IMPLICATIONS The pharmacological activity of CBD and CBD-DMH in HEK293A cells and their modelled binding sites at CB1 and CB2 receptors may explain their in vivo effects and illuminates the difficulties associated with the development of allosteric modulators for CB1 and CB2 receptors. LINKED ARTICLES This article is part of a themed section on 8th European Workshop on Cannabinoid Research. To view the other articles in this section visit http://onlinelibrary.wiley.com/doi/10.1111/bph.v176.10/issuetoc.
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Affiliation(s)
- Mylyne Tham
- College of Pharmacy and Nutrition, University of Saskatchewan, Saskatoon, SK, Canada
| | - Orhan Yilmaz
- College of Pharmacy and Nutrition, University of Saskatchewan, Saskatoon, SK, Canada
| | - Mariam Alaverdashvili
- College of Pharmacy and Nutrition, University of Saskatchewan, Saskatoon, SK, Canada
| | - Melanie E M Kelly
- Department of Pharmacology, Dalhousie University, Halifax, NS, Canada.,Department of Opthamology and Visual Sciences, Dalhousie University, Halifax, NS, Canada
| | | | - Robert B Laprairie
- College of Pharmacy and Nutrition, University of Saskatchewan, Saskatoon, SK, Canada.,Department of Pharmacology, Dalhousie University, Halifax, NS, Canada
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Targeting the Endocannabinoid System for Prevention or Treatment of Chemotherapy-Induced Neuropathic Pain: Studies in Animal Models. Pain Res Manag 2018; 2018:5234943. [PMID: 30147813 PMCID: PMC6083482 DOI: 10.1155/2018/5234943] [Citation(s) in RCA: 15] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/23/2018] [Accepted: 07/10/2018] [Indexed: 12/21/2022]
Abstract
There is a scarcity of drugs to either prevent or properly manage chemotherapy-induced neuropathic pain (CINP). Cannabis or cannabinoids have been reported to improve pain measures in patients with neuropathic pain. For this review, a search was done in PubMed for papers that examined the expression of and/or evaluated the use of cannabinoids or drugs that prevent or treat established CINP in a CB receptor-dependent manner in animal models. Twenty-eight articles that fulfilled the inclusion and exclusion criteria established were analysed. Studies suggest there is a specific deficiency of endocannabinoids in the periphery during CINP. Inhibitors of FAAH and MGL, enzymes that degrade the endocannabinoids, CB receptor agonists, desipramine, and coadministered indomethacin plus minocycline were found to either prevent the development and/or attenuate established CINP in a CB receptor-dependent manner. The studies analysed suggest that targeting the endocannabinoid system for prevention and treatment of CINP is a plausible therapeutic option. Almost 90% of the studies on animal models of CINP analysed utilised male rodents. Taking into consideration clinical and experimental findings that show gender differences in the mechanisms involved in pain including CINP and in response to analgesics, it is imperative that future studies on CINP utilise more female models.
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Gado F, Di Cesare Mannelli L, Lucarini E, Bertini S, Cappelli E, Digiacomo M, Stevenson LA, Macchia M, Tuccinardi T, Ghelardini C, Pertwee RG, Manera C. Identification of the First Synthetic Allosteric Modulator of the CB 2 Receptors and Evidence of Its Efficacy for Neuropathic Pain Relief. J Med Chem 2018; 62:276-287. [PMID: 29990428 DOI: 10.1021/acs.jmedchem.8b00368] [Citation(s) in RCA: 41] [Impact Index Per Article: 6.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/14/2022]
Abstract
The direct activation of cannabinoid receptors (CBRs) results in several beneficial effects; therefore several CBRs ligands have been synthesized and tested in vitro and in vivo. However, none of them reached an advanced phase of clinical development due mainly to side effects on the CNS. Medicinal chemistry approaches are now engaged to develop allosteric modulators that might offer a novel therapeutic approach to achieve potential therapeutic benefits avoiding inherent side effects of orthosteric ligands. Here we identify the first ever synthesized positive allosteric modulator (PAM) that targets CB2Rs. The evidence for this was obtained using [3H]CP55940 and [35S]GTPγS binding assays. This finding will be useful for the characterization of allosteric binding site(s) on CB2Rs which will be essential for the further development of CB2R allosteric modulators. Moreover, the new CB2R PAM displayed antinociceptive activity in vivo in an experimental mouse model of neuropathic pain, raising the possibility that it might be a good candidate for clinical development.
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Affiliation(s)
- Francesca Gado
- Department of Pharmacy , University of Pisa , 56126 Pisa , Italy
| | - Lorenzo Di Cesare Mannelli
- Department of Neuroscience, Psychology, Drug Research and Child Health, Section of Pharmacology and Toxicology , University of Florence , 50139 Florence , Italy
| | - Elena Lucarini
- Department of Neuroscience, Psychology, Drug Research and Child Health, Section of Pharmacology and Toxicology , University of Florence , 50139 Florence , Italy
| | - Simone Bertini
- Department of Pharmacy , University of Pisa , 56126 Pisa , Italy
| | - Elena Cappelli
- Department of Pharmacy , University of Pisa , 56126 Pisa , Italy
| | - Maria Digiacomo
- Department of Pharmacy , University of Pisa , 56126 Pisa , Italy
| | - Lesley A Stevenson
- School of Medicine, Medical Sciences and Nutrition, Institute of Medical Sciences , University of Aberdeen , AB25 2ZD Aberdeen , Scotland, U.K
| | - Marco Macchia
- Department of Pharmacy , University of Pisa , 56126 Pisa , Italy
| | - Tiziano Tuccinardi
- Department of Pharmacy , University of Pisa , 56126 Pisa , Italy.,Sbarro Institute for Cancer Research and Molecular Medicine, Center for Biotechnology, College of Science and Technology , Temple University , Philadelphia , Pennsylvania 19122 , United States
| | - Carla Ghelardini
- Department of Neuroscience, Psychology, Drug Research and Child Health, Section of Pharmacology and Toxicology , University of Florence , 50139 Florence , Italy
| | - Roger G Pertwee
- School of Medicine, Medical Sciences and Nutrition, Institute of Medical Sciences , University of Aberdeen , AB25 2ZD Aberdeen , Scotland, U.K
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87
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Curry ZA, Wilkerson JL, Bagdas D, Kyte SL, Patel N, Donvito G, Mustafa MA, Poklis JL, Niphakis MJ, Hsu KL, Cravatt BF, Gewirtz DA, Damaj MI, Lichtman AH. Monoacylglycerol Lipase Inhibitors Reverse Paclitaxel-Induced Nociceptive Behavior and Proinflammatory Markers in a Mouse Model of Chemotherapy-Induced Neuropathy. J Pharmacol Exp Ther 2018; 366:169-183. [PMID: 29540562 PMCID: PMC6038031 DOI: 10.1124/jpet.117.245704] [Citation(s) in RCA: 50] [Impact Index Per Article: 8.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/14/2017] [Accepted: 03/08/2018] [Indexed: 02/01/2023] Open
Abstract
Although paclitaxel effectively treats various cancers, its debilitating peripheral neuropathic pain side effects often persist long after treatment has ended. Therefore, a compelling need exists for the identification of novel pharmacologic strategies to mitigate this condition. As inhibitors of monoacylglycerol lipase (MAGL), the primary hydrolytic enzyme of the endogenous cannabinoid, 2-arachidonyolglycerol, produces antinociceptive effects in numerous rodent models of pain, we investigated whether inhibitors of this enzyme (i.e., JZL184 and MJN110) would reverse paclitaxel-induced mechanical allodynia in mice. These drugs dose dependently reversed allodynia with respective ED50 values (95% confidence limit) of 8.4 (5.2-13.6) and 1.8 (1.0-3.3) mg/kg. Complementary genetic and pharmacologic approaches revealed that the antiallodynic effects of each drug require both cannabinoid receptors, CB1 and CB2 MJN110 reduced paclitaxel-mediated increased expression of monocyte chemoattractant protein-1 (MCP-1, CCL2) and phospho-p38 MAPK in dorsal root ganglia as well as MCP-1 in spinal dorsal horn. Whereas the antinociceptive effects of high dose JZL184 (40 mg/kg) underwent tolerance following 6 days of repeated dosing, repeated administration of a threshold dose (i.e., 4 mg/kg) completely reversed paclitaxel-induced allodynia. In addition, we found that the administration of MJN110 to control mice lacked intrinsic rewarding effects in the conditioned place preference (CPP) paradigm. However, it produced a CPP in paclitaxel-treated animals, suggesting a reduced paclitaxel-induced aversive state. Importantly, JZL184 did not alter the antiproliferative and apoptotic effects of paclitaxel in A549 and H460 non-small cell lung cancer cells. Taken together, these data indicate that MAGL inhibitors reverse paclitaxel-induced neuropathic pain without interfering with chemotherapeutic efficacy.
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Affiliation(s)
- Zachary A Curry
- Department of Pharmacology and Toxicology, Virginia Commonwealth University, Richmond, Virginia (Z.A.C., J.L.W., D.B., S.L.K., N.P., G.D., M.A.M., J.L.P., D.A.G., M.I.D., A.H.L.); The Skaggs Institute for Chemical Biology and Department of Chemical Physiology, The Scripps Research Institute, La Jolla, California (M.J.N., B.F.C.); and Department of Chemistry, University of Virginia, Charlottesville, Virginia (K.-L.H.)
| | - Jenny L Wilkerson
- Department of Pharmacology and Toxicology, Virginia Commonwealth University, Richmond, Virginia (Z.A.C., J.L.W., D.B., S.L.K., N.P., G.D., M.A.M., J.L.P., D.A.G., M.I.D., A.H.L.); The Skaggs Institute for Chemical Biology and Department of Chemical Physiology, The Scripps Research Institute, La Jolla, California (M.J.N., B.F.C.); and Department of Chemistry, University of Virginia, Charlottesville, Virginia (K.-L.H.)
| | - Deniz Bagdas
- Department of Pharmacology and Toxicology, Virginia Commonwealth University, Richmond, Virginia (Z.A.C., J.L.W., D.B., S.L.K., N.P., G.D., M.A.M., J.L.P., D.A.G., M.I.D., A.H.L.); The Skaggs Institute for Chemical Biology and Department of Chemical Physiology, The Scripps Research Institute, La Jolla, California (M.J.N., B.F.C.); and Department of Chemistry, University of Virginia, Charlottesville, Virginia (K.-L.H.)
| | - S Lauren Kyte
- Department of Pharmacology and Toxicology, Virginia Commonwealth University, Richmond, Virginia (Z.A.C., J.L.W., D.B., S.L.K., N.P., G.D., M.A.M., J.L.P., D.A.G., M.I.D., A.H.L.); The Skaggs Institute for Chemical Biology and Department of Chemical Physiology, The Scripps Research Institute, La Jolla, California (M.J.N., B.F.C.); and Department of Chemistry, University of Virginia, Charlottesville, Virginia (K.-L.H.)
| | - Nipa Patel
- Department of Pharmacology and Toxicology, Virginia Commonwealth University, Richmond, Virginia (Z.A.C., J.L.W., D.B., S.L.K., N.P., G.D., M.A.M., J.L.P., D.A.G., M.I.D., A.H.L.); The Skaggs Institute for Chemical Biology and Department of Chemical Physiology, The Scripps Research Institute, La Jolla, California (M.J.N., B.F.C.); and Department of Chemistry, University of Virginia, Charlottesville, Virginia (K.-L.H.)
| | - Giulia Donvito
- Department of Pharmacology and Toxicology, Virginia Commonwealth University, Richmond, Virginia (Z.A.C., J.L.W., D.B., S.L.K., N.P., G.D., M.A.M., J.L.P., D.A.G., M.I.D., A.H.L.); The Skaggs Institute for Chemical Biology and Department of Chemical Physiology, The Scripps Research Institute, La Jolla, California (M.J.N., B.F.C.); and Department of Chemistry, University of Virginia, Charlottesville, Virginia (K.-L.H.)
| | - Mohammed A Mustafa
- Department of Pharmacology and Toxicology, Virginia Commonwealth University, Richmond, Virginia (Z.A.C., J.L.W., D.B., S.L.K., N.P., G.D., M.A.M., J.L.P., D.A.G., M.I.D., A.H.L.); The Skaggs Institute for Chemical Biology and Department of Chemical Physiology, The Scripps Research Institute, La Jolla, California (M.J.N., B.F.C.); and Department of Chemistry, University of Virginia, Charlottesville, Virginia (K.-L.H.)
| | - Justin L Poklis
- Department of Pharmacology and Toxicology, Virginia Commonwealth University, Richmond, Virginia (Z.A.C., J.L.W., D.B., S.L.K., N.P., G.D., M.A.M., J.L.P., D.A.G., M.I.D., A.H.L.); The Skaggs Institute for Chemical Biology and Department of Chemical Physiology, The Scripps Research Institute, La Jolla, California (M.J.N., B.F.C.); and Department of Chemistry, University of Virginia, Charlottesville, Virginia (K.-L.H.)
| | - Micah J Niphakis
- Department of Pharmacology and Toxicology, Virginia Commonwealth University, Richmond, Virginia (Z.A.C., J.L.W., D.B., S.L.K., N.P., G.D., M.A.M., J.L.P., D.A.G., M.I.D., A.H.L.); The Skaggs Institute for Chemical Biology and Department of Chemical Physiology, The Scripps Research Institute, La Jolla, California (M.J.N., B.F.C.); and Department of Chemistry, University of Virginia, Charlottesville, Virginia (K.-L.H.)
| | - Ku-Lung Hsu
- Department of Pharmacology and Toxicology, Virginia Commonwealth University, Richmond, Virginia (Z.A.C., J.L.W., D.B., S.L.K., N.P., G.D., M.A.M., J.L.P., D.A.G., M.I.D., A.H.L.); The Skaggs Institute for Chemical Biology and Department of Chemical Physiology, The Scripps Research Institute, La Jolla, California (M.J.N., B.F.C.); and Department of Chemistry, University of Virginia, Charlottesville, Virginia (K.-L.H.)
| | - Benjamin F Cravatt
- Department of Pharmacology and Toxicology, Virginia Commonwealth University, Richmond, Virginia (Z.A.C., J.L.W., D.B., S.L.K., N.P., G.D., M.A.M., J.L.P., D.A.G., M.I.D., A.H.L.); The Skaggs Institute for Chemical Biology and Department of Chemical Physiology, The Scripps Research Institute, La Jolla, California (M.J.N., B.F.C.); and Department of Chemistry, University of Virginia, Charlottesville, Virginia (K.-L.H.)
| | - David A Gewirtz
- Department of Pharmacology and Toxicology, Virginia Commonwealth University, Richmond, Virginia (Z.A.C., J.L.W., D.B., S.L.K., N.P., G.D., M.A.M., J.L.P., D.A.G., M.I.D., A.H.L.); The Skaggs Institute for Chemical Biology and Department of Chemical Physiology, The Scripps Research Institute, La Jolla, California (M.J.N., B.F.C.); and Department of Chemistry, University of Virginia, Charlottesville, Virginia (K.-L.H.)
| | - M Imad Damaj
- Department of Pharmacology and Toxicology, Virginia Commonwealth University, Richmond, Virginia (Z.A.C., J.L.W., D.B., S.L.K., N.P., G.D., M.A.M., J.L.P., D.A.G., M.I.D., A.H.L.); The Skaggs Institute for Chemical Biology and Department of Chemical Physiology, The Scripps Research Institute, La Jolla, California (M.J.N., B.F.C.); and Department of Chemistry, University of Virginia, Charlottesville, Virginia (K.-L.H.)
| | - Aron H Lichtman
- Department of Pharmacology and Toxicology, Virginia Commonwealth University, Richmond, Virginia (Z.A.C., J.L.W., D.B., S.L.K., N.P., G.D., M.A.M., J.L.P., D.A.G., M.I.D., A.H.L.); The Skaggs Institute for Chemical Biology and Department of Chemical Physiology, The Scripps Research Institute, La Jolla, California (M.J.N., B.F.C.); and Department of Chemistry, University of Virginia, Charlottesville, Virginia (K.-L.H.)
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88
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Greco R, Demartini C, Zanaboni AM, Piomelli D, Tassorelli C. Endocannabinoid System and Migraine Pain: An Update. Front Neurosci 2018; 12:172. [PMID: 29615860 PMCID: PMC5867306 DOI: 10.3389/fnins.2018.00172] [Citation(s) in RCA: 46] [Impact Index Per Article: 7.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/21/2017] [Accepted: 03/05/2018] [Indexed: 12/14/2022] Open
Abstract
The trigeminovascular system (TS) activation and the vasoactive release from trigeminal endings, in proximity of the meningeal vessels, are considered two of the main effector mechanisms of migraine attacks. Several other structures and mediators are involved, however, both upstream and alongside the TS. Among these, the endocannabinoid system (ES) has recently attracted considerable attention. Experimental and clinical data suggest indeed a link between dysregulation of this signaling complex and migraine headache. Clinical observations, in particular, show that the levels of anandamide (AEA)—one of the two primary endocannabinoid lipids—are reduced in cerebrospinal fluid and plasma of patients with chronic migraine (CM), and that this reduction is associated with pain facilitation in the spinal cord. AEA is produced on demand during inflammatory conditions and exerts most of its effects by acting on cannabinoid (CB) receptors. AEA is rapidly degraded by fatty acid amide hydrolase (FAAH) enzyme and its levels can be modulated in the peripheral and central nervous system (CNS) by FAAH inhibitors. Inhibition of AEA degradation via FAAH is a promising therapeutic target for migraine pain, since it is presumably associated to an increased availability of the endocannabinoid, specifically at the site where its formation is stimulated (e.g., trigeminal ganglion and/or meninges), thus prolonging its action.
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Affiliation(s)
- Rosaria Greco
- Laboratory of Neurophysiology of Integrative Autonomic Systems, Headache Science Centre, IRCCS Mondino Foundation, Pavia, Italy
| | - Chiara Demartini
- Laboratory of Neurophysiology of Integrative Autonomic Systems, Headache Science Centre, IRCCS Mondino Foundation, Pavia, Italy
| | - Anna M Zanaboni
- Laboratory of Neurophysiology of Integrative Autonomic Systems, Headache Science Centre, IRCCS Mondino Foundation, Pavia, Italy.,Department of Brain and Behavioral Sciences, University of Pavia, Pavia, Italy
| | - Daniele Piomelli
- Department of Anatomy and Neurobiology, University of California, Irvine, Irvine, CA, United States
| | - Cristina Tassorelli
- Laboratory of Neurophysiology of Integrative Autonomic Systems, Headache Science Centre, IRCCS Mondino Foundation, Pavia, Italy.,Department of Brain and Behavioral Sciences, University of Pavia, Pavia, Italy
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89
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Dopart R, Lu D, Lichtman AH, Kendall DA. Allosteric modulators of cannabinoid receptor 1: developing compounds for improved specificity. Drug Metab Rev 2018; 50:3-13. [PMID: 29355030 PMCID: PMC6134837 DOI: 10.1080/03602532.2018.1428342] [Citation(s) in RCA: 26] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/18/2022]
Abstract
The cannabinoid receptor 1 (CB1) is a G protein-coupled receptor (GPCR) that is located primarily in the central nervous system. CB1 is a therapeutic target which may impact pathways to mediate pain, neurodegenerative disorders, hunger, and drug-seeking behavior. Despite these benefits, development of orthosteric therapeutic compounds, which target the endogenous ligand-binding site of CB1, has been challenging due to detrimental side effects including psychoactivity, depression, and suicidal thoughts. However, CB1 also has an allosteric binding site(s), which is topographically distinct from the orthosteric site. Allosteric modulation of CB1 has a number of potential advantages including providing a mechanism for more precise control of downstream pathways and circumventing these side effects. In this review, we summarize the concept of allosteric modulation and focus on the structure-activity relationship studies of the well-characterized allosteric modulators, ORG27569 and PSNCBAM-1 and their derivatives, and a few other recent modulators. We review studies on the properties of these modulators on CB1 signaling in cells and their effects in vivo. While many current allosteric modulators also produce complex outcomes, they provide new advances for the design of CB1 centered therapeutics.
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Affiliation(s)
- Rachel Dopart
- a Department of Pharmaceutical Sciences , University of Connecticut , Storrs , CT , USA
| | - Dai Lu
- b Rangel College of Pharmacy , Health Science Center, Texas A&M University , Kingsville , TX , USA
| | - Aron H Lichtman
- c Department of Pharmacology and Toxicology , Virginia Commonwealth University , Richmond , VA , USA
| | - Debra A Kendall
- a Department of Pharmaceutical Sciences , University of Connecticut , Storrs , CT , USA
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90
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Abstract
Allosteric modulation of the type 1 cannabinoid receptor (CB1R) holds great therapeutic potential. This is because allosteric modulators do not possess intrinsic efficacy, but instead augment (positive allosteric modulation) or diminish (negative allosteric modulation) the receptor's response to endogenous ligand. Consequently, CB1R allosteric modulators have an effect ceiling which allows for the tempering of CB1R signaling without the desensitization, tolerance, dependence, and psychoactivity associated with orthosteric compounds. Pain, movement disorders, epilepsy, obesity are all potential therapeutic targets for CB1R allosteric modulation. Several challenges exist for the development of CB1R allosteric modulators, such as receptor subtype specificity, translation to in vivo systems, and mixed allosteric/agonist/inverse agonist activity. Despite these challenges, elucidation of crystal structures of CB1R and compound design based on structure-activity relationships will advance the field. In this review, we will cover recent progress for CB1R allosteric modulators and discuss the future promise of this research.
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Affiliation(s)
- Mariam Alaverdashvili
- a College of Pharmacy and Nutrition , University of Saskatchewan , Saskatoon , Canada
| | - Robert B Laprairie
- a College of Pharmacy and Nutrition , University of Saskatchewan , Saskatoon , Canada
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91
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Radhakrishnan R, Ross DA. From "Azalla" to Anandamide: Distilling the Therapeutic Potential of Cannabinoids. Biol Psychiatry 2018; 83:e27-e29. [PMID: 29223222 PMCID: PMC5752109 DOI: 10.1016/j.biopsych.2017.11.017] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 11/09/2017] [Revised: 11/11/2017] [Accepted: 11/13/2017] [Indexed: 02/02/2023]
Affiliation(s)
- Rajiv Radhakrishnan
- Department of Psychiatry, Yale University School of Medicine, New Haven, Connecticut.
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92
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Lee WH, Carey LM, Li LL, Xu Z, Lai YY, Courtney MJ, Hohmann AG. ZLc002, a putative small-molecule inhibitor of nNOS interaction with NOS1AP, suppresses inflammatory nociception and chemotherapy-induced neuropathic pain and synergizes with paclitaxel to reduce tumor cell viability. Mol Pain 2018; 14:1744806918801224. [PMID: 30157705 PMCID: PMC6144507 DOI: 10.1177/1744806918801224] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/25/2018] [Revised: 07/16/2018] [Accepted: 08/14/2018] [Indexed: 01/03/2023] Open
Abstract
Elevated N-methyl-D-aspartate receptor activity contributes to central sensitization. Our laboratories and others recently reported that disrupting protein-protein interactions downstream of N-methyl-D-aspartate receptors suppresses pain. Specifically, disrupting binding between the enzyme neuronal nitric oxide synthase and either its upstream (postsynaptic density 95 kDa, PSD95) or downstream (e.g. nitric oxide synthase 1 adaptor protein, NOS1AP) protein partners suppressed inflammatory and/or neuropathic pain. However, the lack of a small-molecule neuronal nitric oxide synthase-NOS1AP inhibitor has hindered efforts to validate the therapeutic utility of disrupting the neuronal nitric oxide synthase-NOS1AP interface as an analgesic strategy. We, therefore, evaluated the ability of a putative small-molecule neuronal nitric oxide synthase-NOS1AP inhibitor ZLc002 to disrupt binding between neuronal nitric oxide synthase and NOS1AP using ex vivo, in vitro, and purified recombinant systems and asked whether ZLc002 would suppress inflammatory and neuropathic pain in vivo. In vitro, ZLc002 reduced co-immunoprecipitation of full-length NOS1AP and neuronal nitric oxide synthase in cultured neurons and in HEK293T cells co-expressing full-length neuronal nitric oxide synthase and NOS1AP. However, using a cell-free biochemical binding assay, ZLc002 failed to disrupt the in vitro binding between His-neuronal nitric oxide synthase1-299 and glutathione S-transferase-NOS1AP400-506, protein sequences containing the required binding domains for this protein-protein interaction, suggesting an indirect mode of action in intact cells. ZLc002 (4-10 mg/kg i.p.) suppressed formalin-evoked inflammatory pain in rats and reduced Fos protein-like immunoreactivity in the lumbar spinal dorsal horn. ZLc002 also suppressed mechanical and cold allodynia in a mouse model of paclitaxel-induced neuropathic pain. Anti-allodynic efficacy was sustained for at least four days of once daily repeated dosing. ZLc002 also synergized with paclitaxel when administered in combination to reduce breast (4T1) or ovarian (HeyA8) tumor cell line viability but did not alter tumor cell viability without paclitaxel. Our results verify that ZLc002 disrupts neuronal nitric oxide synthase-NOS1AP interaction in intact cells and demonstrate, for the first time, that systemic administration of a putative small-molecule inhibitor of neuronal nitric oxide synthase-NOS1AP suppresses inflammatory and neuropathic pain.
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Affiliation(s)
- Wan-Hung Lee
- Biochemistry Interdisciplinary Graduate Program, Molecular and
Cellular Biochemistry Department,
Indiana
University, Bloomington, IN, USA
| | - Lawrence M Carey
- Program in Neuroscience,
Indiana
University, Bloomington, IN, USA
- Department of Psychological and Brain Sciences, Indiana
University, Bloomington, IN, USA
| | - Li-Li Li
- Neuronal Signalling Lab, Turku Centre for Biotechnology,
University of Turku; Åbo Academy University, Turku, Finland
- Turku Centre for Biotechnology and Institute of Biomedicine,
Screening Unit, University of Turku, Turku, Finland
| | - Zhili Xu
- Department of Psychological and Brain Sciences, Indiana
University, Bloomington, IN, USA
| | - Yvonne Y Lai
- Department of Psychological and Brain Sciences, Indiana
University, Bloomington, IN, USA
- Anagin, Inc., Indianapolis, IN, USA
| | - Michael J Courtney
- Neuronal Signalling Lab, Turku Centre for Biotechnology,
University of Turku; Åbo Academy University, Turku, Finland
- Turku Centre for Biotechnology and Institute of Biomedicine,
Screening Unit, University of Turku, Turku, Finland
- Turku Brain and Mind Center, Turku, Finland
| | - Andrea G Hohmann
- Biochemistry Interdisciplinary Graduate Program, Molecular and
Cellular Biochemistry Department,
Indiana
University, Bloomington, IN, USA
- Program in Neuroscience,
Indiana
University, Bloomington, IN, USA
- Department of Psychological and Brain Sciences, Indiana
University, Bloomington, IN, USA
- Gill Center for Biomolecular Science, Bloomington, IN, USA
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93
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Cannabinoid Receptor 1 Positive Allosteric Modulators for Posttraumatic Stress Disorder. Neuropsychopharmacology 2018; 43:226-227. [PMID: 29192662 PMCID: PMC5719119 DOI: 10.1038/npp.2017.230] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
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94
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Cairns EA, Szczesniak AM, Straiker AJ, Kulkarni PM, Pertwee RG, Thakur GA, Baldridge WH, Kelly MEM. The In Vivo Effects of the CB 1-Positive Allosteric Modulator GAT229 on Intraocular Pressure in Ocular Normotensive and Hypertensive Mice. J Ocul Pharmacol Ther 2017; 33:582-590. [PMID: 28719234 DOI: 10.1089/jop.2017.0037] [Citation(s) in RCA: 17] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/21/2022] Open
Abstract
PURPOSE Orthosteric cannabinoid receptor 1 (CB1) activation leads to decreases in intraocular pressure (IOP). However, use of orthosteric CB1 agonists chronically has several disadvantages, limiting their usefulness as clinically relevant drugs. Allosteric modulators interact with topographically distinct sites to orthosteric ligands and may be useful to circumvent some of these disadvantages. The purpose of this study was to investigate the effects of the novel CB1-positive allosteric modulator (PAM) GAT229 on IOP. METHODS IOP was measured using rebound tonometry in anesthetized normotensive C57Bl/6 mice and in a genetic model of ocular hypertension [nose, eyes, ears (nee) mice] before drug administration, and at 1, 6, and 12 h thereafter. RESULTS In normotensive mice, topical administration of 5 μL GAT229 alone at either 0.2% or 2% did not reduce IOP. However, a subthreshold dose (0.25%) of the nonselective orthosteric CB1 agonist WIN 55,212-2, when combined with 0.2% GAT229, significantly reduced IOP compared with vehicle at 6 and 12 h. Similarly, combination of subthreshold Δ9-tetrahydrocannabinol (a nonselective orthosteric CB1 agonist; 1 mg/kg) with topical 0.2% GAT229 produced IOP lowering at 6 h. In nee mice, administration of topical 0.2% GAT229 or 10 mg/kg GAT229 alone was sufficient to lower IOP at 6 and 12 h, and 12 h, respectively. CONCLUSIONS The CB1 PAM GAT229 reduces IOP in ocular hypertensive mice and enhanced CB1-mediated IOP reduction when combined with subthreshold CB1 orthosteric ligands in normotensive mice. Administration of CB1 PAMs may provide a novel approach to reduce IOP with fewer of the disadvantages associated with orthosteric CB1 activation.
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Affiliation(s)
- Elizabeth A Cairns
- 1 Department of Pharmacology, Dalhousie University , Halifax, Nova Scotia, Canada
| | | | - Alex J Straiker
- 2 Department of Psychological and Brain Sciences, Indiana University , Bloomington, Indiana
| | - Pushkar M Kulkarni
- 3 Department of Pharmaceutical Sciences School of Pharmacy, Bouvé College of Health Sciences, Northeastern University , Boston, Massachusetts
| | - Roger G Pertwee
- 4 School of Medicine, Medical Sciences, and Nutrition, Institute of Medical Sciences, University of Aberdeen , Aberdeen, Scotland
| | - Ganesh A Thakur
- 3 Department of Pharmaceutical Sciences School of Pharmacy, Bouvé College of Health Sciences, Northeastern University , Boston, Massachusetts
| | - William H Baldridge
- 5 Department of Medical Neuroscience, Dalhousie University , Halifax, Nova Scotia, Canada .,6 Department of Ophthalmology and Visual Sciences, Dalhousie University , Halifax, Nova Scotia, Canada
| | - Melanie E M Kelly
- 1 Department of Pharmacology, Dalhousie University , Halifax, Nova Scotia, Canada .,6 Department of Ophthalmology and Visual Sciences, Dalhousie University , Halifax, Nova Scotia, Canada
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