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Kosar M, Mach L, Carreira EM, Nazaré M, Pacher P, Grether U. Patent review of cannabinoid receptor type 2 (CB 2R) modulators (2016-present). Expert Opin Ther Pat 2024. [PMID: 38886185 DOI: 10.1080/13543776.2024.2368745] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/08/2024] [Accepted: 06/12/2024] [Indexed: 06/20/2024]
Abstract
INTRODUCTION Cannabinoid receptor type 2 (CB2R), predominantly expressed in immune tissues, is believed to play a crucial role within the body's protective mechanisms. Its modulation holds immense therapeutic promise for addressing a wide spectrum of disbiotic conditions, including cardiovascular, gastrointestinal, liver, kidney, neurodegenerative, psychiatric, bone, skin, and autoimmune diseases, as well as lung disorders, cancer, and pain management. AREAS COVERED This review is an account of patents from 2016 up to 2023 which describes novel CB2R ligands, therapeutic applications, synthesis as well as formulations of CB2R modulators. EXPERT OPINION The patents cover a vast, structurally diverse chemical space. The focus of CB2R ligand development has shifted from unselective dual cannabinoid receptor type 1 (CB1R) and 2 agonists toward agonists with high selectivity over CB1R, particularly for indications associated with inflammation and tissue injury. Currently, there are at least eight CB2R agonists and one antagonist in active clinical development. A better understanding of the endocannabinoid system (ECS) and in particular of CB2R pharmacology is required to unlock the receptor's full therapeutic potential.
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Affiliation(s)
- Miroslav Kosar
- Laboratorium für Organische Chemie, Eidgenössische Technische Hochschule Zürich, Zürich, Switzerland
| | - Leonard Mach
- Medicinal Chemistry, Leibniz-Forschungsinstitut für Molekulare Pharmakologie (FMP)Berlin, Berlin, Germany
| | - Erick M Carreira
- Laboratorium für Organische Chemie, Eidgenössische Technische Hochschule Zürich, Zürich, Switzerland
| | - Marc Nazaré
- Medicinal Chemistry, Leibniz-Forschungsinstitut für Molekulare Pharmakologie (FMP)Berlin, Berlin, Germany
| | - Pal Pacher
- National Institute on Alcohol Abuse and Alcoholism, National Institutes of Health, Rockville, MD, USA
| | - Uwe Grether
- Roche Pharma Research & Early Development, Roche Innovation Center Basel, F. Hoffmann-La Roche Ltd, Basel, Switzerland
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Green HM, Manning JJ, Greig IR, Ross RA, Finlay DB, Glass M. Positive allosteric modulation of the cannabinoid CB 1 receptor potentiates endocannabinoid signalling and changes ERK1/2 phosphorylation kinetics. Br J Pharmacol 2024. [PMID: 38831545 DOI: 10.1111/bph.16433] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/28/2023] [Revised: 04/16/2024] [Accepted: 04/20/2024] [Indexed: 06/05/2024] Open
Abstract
BACKGROUND AND PURPOSE Activation of CB1 by exogenous agonists causes adverse effects in vivo. Positive allosteric modulation may offer improved therapeutic potential and a reduced on-target adverse effect profile compared with orthosteric agonists, due to reduced desensitisation/tolerance, but this has not been directly tested. This study investigated the ability of PAMs/ago-PAMs to induce receptor regulation pathways, including desensitisation and receptor internalisation. EXPERIMENTAL APPROACH Bioluminescence resonance energy transfer (BRET) assays in HEK293 cells were performed to investigate G protein dissociation, ERK1/2 phosphorylation and β-arrestin 2 translocation, while immunocytochemistry was performed to measure internalisation of CB1 in response to the PAMs ZCZ011, GAT229 and ABD1236 alone and in combination with the orthosteric agonists AEA, 2-AG, and AMB-FUBINACA. KEY RESULTS ZCZ011, GAT229 and ABD1236 were allosteric agonists in all pathways tested. The ago-PAM ZCZ011 induced a biphasic ERK1/2 phosphorylation time course compared to transient activation by orthosteric agonists. In combination with 2-AG but not AEA or AMB-FUBINACA, ZCZ011 and ABD1236 caused the transient peak of ERK1/2 phosphorylation to become sustained. All PAMs increased the potency and efficacy of AEA-induced signalling in all pathways tested; however, no notable potentiation of 2-AG or AMB-FUBINACA was observed. CONCLUSION AND IMPLICATIONS Ago-PAMs can potentiate endocannabinoid CB1 agonism by AEA to a larger extent compared with 2-AG. However, all compounds were found to be allosteric agonists and induce activation of CB1 in the absence of endocannabinoid, including β-arrestin 2 recruitment and internalisation. Thus, the spatiotemporal signalling of endogenous cannabinoids will not be retained in vivo.
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Affiliation(s)
- Hayley M Green
- Department of Pharmacology and Toxicology, School of Biomedical Sciences, University of Otago, Dunedin, New Zealand
| | - Jamie J Manning
- Department of Pharmacology and Toxicology, School of Biomedical Sciences, University of Otago, Dunedin, New Zealand
| | - Ian R Greig
- School of Medicine, Medical Sciences and Nutrition, University of Aberdeen, Aberdeen, UK
| | - Ruth A Ross
- Department of Pharmacology and Toxicology, University of Toronto, Toronto, Canada
| | - David B Finlay
- Department of Pharmacology and Toxicology, School of Biomedical Sciences, University of Otago, Dunedin, New Zealand
| | - Michelle Glass
- Department of Pharmacology and Toxicology, School of Biomedical Sciences, University of Otago, Dunedin, New Zealand
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Janero DR. Current strategic trends in drug discovery: the present as prologue. Expert Opin Drug Discov 2024; 19:147-159. [PMID: 37936504 DOI: 10.1080/17460441.2023.2275640] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/21/2023] [Accepted: 10/23/2023] [Indexed: 11/09/2023]
Abstract
INTRODUCTION Escalating costs and inherent uncertainties associated with drug discovery invite initiatives to improve its efficiency and de-risk campaigns for inventing better therapeutics. One such initiative involves recognizing and exploiting current approaches in therapeutics invention with molecular mechanisms of action that hold promise for designing and targeting new chemical entities as drugs. AREAS COVERED This perspective considers the current contextual framework around three drug-discovery approaches and evaluates their potential to help identify new targets/modalities in small-molecule molecular pharmacology: diversifying ligand-directed phenotypes for G protein-coupled receptor (GPCR) pharmacotherapeutic signaling; developing therapeutic-protein degraders and stabilizers for proximity-inducing pharmacology; and mining organelle biology for druggable therapeutic targets. EXPERT OPINION The contemporary drug-discovery approaches examined appear generalizable and versatile to have applications in therapeutics invention beyond those case studies discussed herein. Accordingly, they may be considered strategic trends worthy of note in advancing the field toward novel ways of addressing pharmacotherapeutically unmet medical needs.
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Affiliation(s)
- David R Janero
- Department of Pharmaceutical Sciences, School of Pharmacy and Pharmaceutical Sciences, and Health Sciences Entrepreneurs, Northeastern University, Boston, MA, USA
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Green HM, Fellner DMJ, Finlay DB, Furkert DP, Glass M. Determination of the Cannabinoid CB1 Receptor's Positive Allosteric Modulator Binding Site through Mutagenesis Studies. Pharmaceuticals (Basel) 2024; 17:154. [PMID: 38399369 PMCID: PMC10892375 DOI: 10.3390/ph17020154] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/14/2023] [Revised: 01/18/2024] [Accepted: 01/21/2024] [Indexed: 02/25/2024] Open
Abstract
Positive allosteric modulators (PAMs) of the cannabinoid CB1 receptor (CB1) offer potential therapeutic advantages in the treatment of neuropathic pain and addiction by avoiding the adverse effects associated with orthosteric CB1 activation. Here, molecular modeling and mutagenesis were used to identify residues central to PAM activity at CB1. Six putative allosteric binding sites were identified in silico, including novel sites previously associated with cholesterol binding, and key residues within each site were mutated to alanine. The recently determined ZCZ011 binding site was found to be essential for allosteric agonism, as GAT228, GAT229 and ZCZ011 all increased wild-type G protein dissociation in the absence of an orthosteric ligand; activity that was abolished in mutants F191A3.27 and I169A2.56. PAM activity was demonstrated for ZCZ011 in the presence of the orthosteric ligand CP55940, which was only abolished in I169A2.56. In contrast, the PAM activity of GAT229 was reduced for mutants R220A3.56, L404A8.50, F191A3.27 and I169A2.56. This indicates that allosteric modulation may represent the net effect of binding at multiple sites, and that allosteric agonism is likely to be mediated via the ZCZ011 site. This study underlines the need for detailed understanding of ligand receptor interactions in the search for pure CB1 allosteric modulators.
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Affiliation(s)
- Hayley M. Green
- Department of Pharmacology and Toxicology, School of Biomedical Sciences, University of Otago, Dunedin 9016, New Zealand; (H.M.G.); (D.B.F.)
| | - Daniel M. J. Fellner
- School of Chemical Sciences, Faculty of Science, University of Auckland, Auckland 1142, New Zealand; (D.M.J.F.); (D.P.F.)
| | - David B. Finlay
- Department of Pharmacology and Toxicology, School of Biomedical Sciences, University of Otago, Dunedin 9016, New Zealand; (H.M.G.); (D.B.F.)
| | - Daniel P. Furkert
- School of Chemical Sciences, Faculty of Science, University of Auckland, Auckland 1142, New Zealand; (D.M.J.F.); (D.P.F.)
- Maurice Wilkins Centre for Molecular Biodiscovery, The University of Auckland, Auckland 1142, New Zealand
| | - Michelle Glass
- Department of Pharmacology and Toxicology, School of Biomedical Sciences, University of Otago, Dunedin 9016, New Zealand; (H.M.G.); (D.B.F.)
- Maurice Wilkins Centre for Molecular Biodiscovery, The University of Auckland, Auckland 1142, New Zealand
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Bagher AM, Binmahfouz LS, Shaik RA, Eid BG. Cannabinoid receptor 1 positive allosteric modulator (GAT229) attenuates cisplatin-induced neuropathic pain in mice. Saudi Pharm J 2023; 31:255-264. [PMID: 36942271 PMCID: PMC10023546 DOI: 10.1016/j.jsps.2022.12.011] [Citation(s) in RCA: 4] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/04/2022] [Accepted: 12/26/2022] [Indexed: 12/31/2022] Open
Abstract
Chemotherapy-induced peripheral neuropathy (CIPN) is one of chemotherapies' most often documented side effects. Patients with CIPN experience spontaneous burning, numbness, tingling, and neuropathic pain in their feet and hands. Currently, there is no effective pharmacological treatment to prevent or treat CIPN. Activating the cannabinoid receptor type 1 (CB1) by orthosteric agonists has shown promising results in alleviating the pain and neuroinflammation associated with CIPN. However, the use of CB1 orthosteric agonists is linked to undesirable side effects. Unlike the CB1 orthosteric agonists, CB1 positive allosteric modulators (PAMs) don't produce any psychoactive effects, tolerance, or dependence. Previous studies have shown that CB1 PAMs exhibit antinociceptive effects in inflammatory and neuropathic rodent models. This study aimed to investigate the potential benefits of the newly synthesized GAT229, a pure CB1 PAM, in alleviating neuropathic pain and slowing the progression of CIPN. GAT229 was evaluated in a cisplatin-induced (CIS) mouse model of peripheral neuropathic pain (3 mg/kg/d, 28 d, i.p.). GAT229 attenuated and slowed the progression of thermal hyperalgesia and mechanical allodynia induced by CIS, as evaluated by the hotplate test and von Frey filament test. GAT229 reduced the expression of proinflammatory cytokines in the dorsal root ganglia (DRG) neurons. Furthermore, GAT229 attenuated nerve injuries by normalizing the brain-derived neurotrophic factor and the nerve growth factor mRNA expression levels in the DRG neurons. The CB1 receptor antagonist/inverse agonist AM251 blocked GAT229-mediated beneficial effects. According to our data, we suggest that CB1 PAMs might be beneficial in alleviating neuropathic pain and slowing the progression of CIPN.
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Affiliation(s)
- Amina M. Bagher
- Corresponding author at: Department of Pharmacology and Toxicology, King Abdulaziz University, Jeddah, Saudi Arabia.
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Scheyer A, Yasmin F, Naskar S, Patel S. Endocannabinoids at the synapse and beyond: implications for neuropsychiatric disease pathophysiology and treatment. Neuropsychopharmacology 2023; 48:37-53. [PMID: 36100658 PMCID: PMC9700791 DOI: 10.1038/s41386-022-01438-7] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 06/01/2022] [Revised: 08/10/2022] [Accepted: 08/18/2022] [Indexed: 11/09/2022]
Abstract
Endocannabinoids (eCBs) are lipid neuromodulators that suppress neurotransmitter release, reduce postsynaptic excitability, activate astrocyte signaling, and control cellular respiration. Here, we describe canonical and emerging eCB signaling modes and aim to link adaptations in these signaling systems to pathological states. Adaptations in eCB signaling systems have been identified in a variety of biobehavioral and physiological process relevant to neuropsychiatric disease states including stress-related disorders, epilepsy, developmental disorders, obesity, and substance use disorders. These insights have enhanced our understanding of the pathophysiology of neurological and psychiatric disorders and are contributing to the ongoing development of eCB-targeting therapeutics. We suggest future studies aimed at illuminating how adaptations in canonical as well as emerging cellular and synaptic modes of eCB signaling contribute to disease pathophysiology or resilience could further advance these novel treatment approaches.
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Affiliation(s)
| | - Farhana Yasmin
- Northwestern Center for Psychiatric Neuroscience, Chicago, IL, USA
- Department of Psychiatry and Behavioral Sciences, Northwestern University Feinberg School of Medicine, Chicago, IL, 60611, USA
| | - Saptarnab Naskar
- Northwestern Center for Psychiatric Neuroscience, Chicago, IL, USA
- Department of Psychiatry and Behavioral Sciences, Northwestern University Feinberg School of Medicine, Chicago, IL, 60611, USA
| | - Sachin Patel
- Northwestern Center for Psychiatric Neuroscience, Chicago, IL, USA.
- Department of Psychiatry and Behavioral Sciences, Northwestern University Feinberg School of Medicine, Chicago, IL, 60611, USA.
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Green H, Finlay DB, Ross RA, Greig IR, Duffull SB, Glass M. In Vitro Characterization of 6-Methyl-3-(2-nitro-1-(thiophen-2-yl)ethyl)-2-phenyl-1 H-indole (ZCZ011) at the Type 1 Cannabinoid Receptor: Allosteric Agonist or Allosteric Modulator? ACS Pharmacol Transl Sci 2022; 5:1279-1291. [PMID: 36524007 PMCID: PMC9745890 DOI: 10.1021/acsptsci.2c00160] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/15/2022] [Indexed: 11/23/2022]
Abstract
Orthosteric activation of CB1 is known to cause a plethora of adverse side effects in vivo. Allosteric modulation is an exciting therapeutic approach and is hoped to offer improved therapeutic potential and a reduced on-target side effect profile compared to orthosteric agonists. This study aimed to systematically characterize the in vitro activity of the positive allosteric modulator ZCZ011, explicitly considering its effects on receptor regulation. HEK293 cells expressing hCB1 receptors were used to characterize ZCZ011 alone and in combination with orthosteric agonists. Real-time BRET approaches were employed for G protein dissociation, cAMP signaling, and β-arrestin translocation. Characterization also included ERK1/2 phosphorylation (PerkinElmer AlphaLISA) and receptor internalization. ZCZ011 is an allosteric agonist of CB1 in all pathways tested, with a similar signaling profile to that of the partial orthosteric agonist Δ9-tetrahydrocannabinol. ZCZ011 also showed limited positive allosteric modulation in increasing the potency and efficacy of THC-induced ERK1/2 phosphorylation, β-arrestin translocation, and receptor internalization. However, no positive allosteric modulation was observed for ZCZ011 in combination with either CP55940 or AMB-FUBINACA, in G protein dissociation, nor cAMP inhibition. Our study suggests that ZCZ011 is an allosteric agonist, with effects that are often difficult to differentiate from those of orthosteric agonists. Together with its pronounced agonist activity, the limited extent of ZCZ011 positive allosteric modulation suggests that further investigation into the differences between allosteric and orthosteric agonism is required, especially in receptor regulation end points.
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Affiliation(s)
- Hayley
M. Green
- Department
of Pharmacology and Toxicology, School of Biomedical Sciences, University of Otago, Dunedin9054, New
Zealand
| | - David B. Finlay
- Department
of Pharmacology and Toxicology, School of Biomedical Sciences, University of Otago, Dunedin9054, New
Zealand
| | - Ruth A. Ross
- Department
of Pharmacology and Toxicology, Faculty of Medicine, University of Toronto, TorontoM5S 1A8, Canada
| | - Iain R. Greig
- School
of Medicine, Medical Sciences and Nutrition, University of Aberdeen, AberdeenAB24 3FX, U.K.
| | - Stephen B. Duffull
- Otago
Pharmacometrics Group, School of Pharmacy, University of Otago, Dunedin9016, New Zealand
| | - Michelle Glass
- Department
of Pharmacology and Toxicology, School of Biomedical Sciences, University of Otago, Dunedin9054, New
Zealand
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CB 1R, CB 2R and TRPV1 expression and modulation in in vivo, animal glaucoma models: A systematic review. Biomed Pharmacother 2022; 150:112981. [PMID: 35468582 DOI: 10.1016/j.biopha.2022.112981] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/10/2022] [Revised: 04/06/2022] [Accepted: 04/14/2022] [Indexed: 11/24/2022] Open
Abstract
BACKGROUND The endocannabinoid system (ECS) is a complex biological regulatory system. Its expression and functionality have been widely investigated in ocular tissues. Recent data have reported its modulation to be valid in determining an ocular hypotensive and a neuroprotective effect in preclinical animal models of glaucoma. AIM This study aimed to explore the available literature on cannabinoid receptor 1 (CB1R), cannabinoid receptor 2 (CB2R), and transient receptor potential vanilloid 1 (TRPV1) expression in the trabecular meshwork (TM), ciliary body (CB), and retina as well as their ocular hypotensive and neuroprotective effects in preclinical, in vivo, animal glaucoma models. MATERIALS AND METHODS The study adhered to both PRISMA and SYRCLE guidelines. Sixty-nine full-length articles were included in the final analysis. RESULTS Preclinical studies indicated a widespread distribution of CB1R, CB2R, and TRPV1 in the TM, CB, and retina, although receptor-, age-, and species-dependent differences were observed. CB1R and CB2R modulation have been shown to exert ocular hypotensive effects in preclinical models via the regulation of inflow and outflow pathways. Retinal cell neuroprotection has been achieved in several experimental models, mediated by agonists and antagonists of CB1R, CB2R, and TRPV1. DISCUSSION Despite the growing body of preclinical data regarding the expression and modulation of ECS in ocular tissues, the mechanisms responsible for the hypotensive and neuroprotective efficacy exerted by this system remain largely elusive. Research on this topic is advocated to further substantiate the hypothesis that the ECS is a new potential therapeutic target in the context of glaucoma.
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Leo LM, Abood ME. CB1 Cannabinoid Receptor Signaling and Biased Signaling. Molecules 2021; 26:molecules26175413. [PMID: 34500853 PMCID: PMC8433814 DOI: 10.3390/molecules26175413] [Citation(s) in RCA: 40] [Impact Index Per Article: 13.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/29/2021] [Revised: 08/30/2021] [Accepted: 09/03/2021] [Indexed: 12/11/2022] Open
Abstract
The CB1 cannabinoid receptor is a G-protein coupled receptor highly expressed throughout the central nervous system that is a promising target for the treatment of various disorders, including anxiety, pain, and neurodegeneration. Despite the wide therapeutic potential of CB1, the development of drug candidates is hindered by adverse effects, rapid tolerance development, and abuse potential. Ligands that produce biased signaling—the preferential activation of a signaling transducer in detriment of another—have been proposed as a strategy to dissociate therapeutic and adverse effects for a variety of G-protein coupled receptors. However, biased signaling at the CB1 receptor is poorly understood due to a lack of strongly biased agonists. Here, we review studies that have investigated the biased signaling profile of classical cannabinoid agonists and allosteric ligands, searching for a potential therapeutic advantage of CB1 biased signaling in different pathological states. Agonist and antagonist bound structures of CB1 and proposed mechanisms of action of biased allosteric modulators are used to discuss a putative molecular mechanism for CB1 receptor activation and biased signaling. Current studies suggest that allosteric binding sites on CB1 can be explored to yield biased ligands that favor or hinder conformational changes important for biased signaling.
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Onofrychuk TJ, Cai S, McElroy DL, Roebuck AJ, Greba Q, Garai S, Thakur GA, Laprairie RB, Howland JG. Effects of the cannabinoid receptor 1 positive allosteric modulator GAT211 and acute MK-801 on visual attention and impulsivity in rats assessed using the five-choice serial reaction time task. Prog Neuropsychopharmacol Biol Psychiatry 2021; 109:110235. [PMID: 33373679 DOI: 10.1016/j.pnpbp.2020.110235] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 07/20/2020] [Revised: 12/07/2020] [Accepted: 12/21/2020] [Indexed: 12/12/2022]
Abstract
Altered interactions between endocannabinoid and glutamate signaling may be involved in the pathophysiology of schizophrenia and acute psychosis. As cognitive disturbances are involved in schizophrenia, increased understanding of the roles of these neurotransmitter systems in cognition may lead to the development of novel therapeutics for disorder. In the present study, we examined the effects of a recently synthesized cannabinoid receptor 1 (CB1R) positive allosteric modulator GAT211 in a rodent model of acute psychosis induced by systemic treatment with MK-801. To assess cognitive function, we used the Five-Choice Serial Reaction Time (5CSRT) task, conducted in touchscreen-equipped operant conditioning chambers. Our measures of primary interest were accuracy - indicative of visual attentional capacity - and the number of premature responses - indicative of impulsivity. We also measured latencies, omissions, and perseverative responding during all test sessions. Thirteen adult male Long Evans rats were trained on the 5CSRT and were then tested using a repeated measures design with acute MK-801 (0 or 0.15 mg/kg, i.p.) and GAT211 (0, 3, or 10 mg/kg, i.p.) administration. Acute MK-801 severely impaired accuracy, increased omissions, and increased the number of premature responses. MK-801 also significantly increased correct response latencies, without significant effects on incorrect or reward correction latencies. GAT211 had no significant effects when administered alone, or in combination with acute MK-801. These data confirm the dramatic effects of acute MK-801 treatment on behavioral measures of attention and impulsivity. Continued investigation of CB1R positive allosteric modulators as potential treatments for the cognitive symptoms of schizophrenia and related disorders should be pursued in other rodent models.
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Affiliation(s)
- Timothy J Onofrychuk
- Department of Anatomy, Physiology, and Pharmacology, University of Saskatchewan, Saskatoon, SK S7N 5E5, Canada
| | - Shuang Cai
- Department of Anatomy, Physiology, and Pharmacology, University of Saskatchewan, Saskatoon, SK S7N 5E5, Canada
| | - Dan L McElroy
- Department of Anatomy, Physiology, and Pharmacology, University of Saskatchewan, Saskatoon, SK S7N 5E5, Canada
| | | | - Quentin Greba
- Department of Anatomy, Physiology, and Pharmacology, University of Saskatchewan, Saskatoon, SK S7N 5E5, Canada
| | - Sumanta Garai
- Department of Pharmaceutical Sciences, School of Pharmacy, Bouvé College of Health Sciences, Northeastern University, Boston, MA 02115, USA
| | - Ganesh A Thakur
- Department of Pharmaceutical Sciences, School of Pharmacy, Bouvé College of Health Sciences, Northeastern University, Boston, MA 02115, USA
| | - Robert B Laprairie
- College of Pharmacy and Nutrition, University of Saskatchewan, Saskatoon, SK S7N 5E5, Canada
| | - John G Howland
- Department of Anatomy, Physiology, and Pharmacology, University of Saskatchewan, Saskatoon, SK S7N 5E5, Canada.
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Garai S, Leo LM, Szczesniak AM, Hurst DP, Schaffer PC, Zagzoog A, Black T, Deschamps JR, Miess E, Schulz S, Janero DR, Straiker A, Pertwee RG, Abood ME, Kelly MEM, Reggio PH, Laprairie RB, Thakur GA. Discovery of a Biased Allosteric Modulator for Cannabinoid 1 Receptor: Preclinical Anti-Glaucoma Efficacy. J Med Chem 2021; 64:8104-8126. [PMID: 33826336 DOI: 10.1021/acs.jmedchem.1c00040] [Citation(s) in RCA: 17] [Impact Index Per Article: 5.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/13/2022]
Abstract
We apply the magic methyl effect to improve the potency/efficacy of GAT211, the prototypic 2-phenylindole-based cannabinoid type-1 receptor (CB1R) agonist-positive allosteric modulator (ago-PAM). Introducing a methyl group at the α-position of nitro group generated two diastereomers, the greater potency and efficacy of erythro, (±)-9 vs threo, (±)-10 constitutes the first demonstration of diastereoselective CB1R-allosteric modulator interaction. Of the (±)-9 enantiomers, (-)-(S,R)-13 evidenced improved potency over GAT211 as a CB1R ago-PAM, whereas (+)-(R,S)-14 was a CB1R allosteric agonist biased toward G protein- vs β-arrestin1/2-dependent signaling. (-)-(S,R)-13 and (+)-(R,S)-14 were devoid of undesirable side effects (triad test), and (+)-(R,S)-14 reduced intraocular pressure with an unprecedentedly long duration of action in a murine glaucoma model. (-)-(S,R)-13 docked into both a CB1R extracellular PAM and intracellular allosteric-agonist site(s), whereas (+)-(R,S)-14 preferentially engaged only the latter. Exploiting G-protein biased CB1R-allosteric modulation can offer safer therapeutic candidates for glaucoma and, potentially, other diseases.
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Affiliation(s)
- Sumanta Garai
- Department of Pharmaceutical Sciences, 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
| | - Anna-Maria Szczesniak
- Department of Pharmacology and Department of Ophthalmology and Visual Sciences, Dalhousie University, Halifax, Nova Scotia B3H 4R2, Canada
| | - Dow P Hurst
- Center for Drug Discovery, University of North Carolina Greensboro, Greensboro, North Carolina 27402, United States
| | - Peter C Schaffer
- Department of Pharmaceutical Sciences, Bouvé College of Health Sciences, Northeastern University, Boston, Massachusetts 02115, United States
| | - Ayat Zagzoog
- College of Pharmacy and Nutrition, University of Saskatchewan, 104 Clinic Pl, Saskatoon, Saskatchewan S7N2Z4, Canada
| | - Tallan Black
- College of Pharmacy and Nutrition, University of Saskatchewan, 104 Clinic Pl, Saskatoon, Saskatchewan S7N2Z4, Canada
| | - Jeffrey R Deschamps
- Naval Research Laboratory, Code 6930, 4555 Overlook Avenue, Washington, District of Columbia 20375, United States
| | - Elke Miess
- Department of Pharmacology and Toxicology, Jena University Hospital-Friedrich Schiller University Jena, D-07747 Jena, Germany
| | - Stefan Schulz
- Department of Pharmacology and Toxicology, Jena University Hospital-Friedrich Schiller University Jena, D-07747 Jena, Germany
| | - David R Janero
- Department of Pharmaceutical Sciences, Bouvé College of Health Sciences, Northeastern University, Boston, Massachusetts 02115, United States
| | - Alex Straiker
- The Gill Center and the Department of Psychological & Brain Sciences, Indiana University, 1101 E. 10th St, 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
| | - Mary E Abood
- Center for Substance Abuse Research, Lewis Katz School of Medicine, Temple University, Philadelphia, Pennsylvania 19140, United States
| | - Melanie E M Kelly
- Department of Pharmacology and Department of Ophthalmology and Visual Sciences, Dalhousie University, Halifax, Nova Scotia B3H 4R2, Canada
| | - 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, Saskatchewan S7N2Z4, Canada
- Department of Pharmacology and Department of Ophthalmology and Visual Sciences, Dalhousie University, Halifax, Nova Scotia B3H 4R2, Canada
| | - Ganesh A Thakur
- Department of Pharmaceutical Sciences, Bouvé College of Health Sciences, Northeastern University, Boston, Massachusetts 02115, United States
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Positive Allosteric Modulation of CB1 and CB2 Cannabinoid Receptors Enhances the Neuroprotective Activity of a Dual CB1R/CB2R Orthosteric Agonist. Life (Basel) 2020; 10:life10120333. [PMID: 33302569 PMCID: PMC7763181 DOI: 10.3390/life10120333] [Citation(s) in RCA: 9] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/04/2020] [Revised: 12/04/2020] [Accepted: 12/06/2020] [Indexed: 12/13/2022] Open
Abstract
Preclinical studies highlighted that compounds targeting cannabinoid receptors could be useful for developing novel therapies against neurodegenerative disorders. However, the chronic use of orthosteric agonists alone has several disadvantages, limiting their usefulness as clinically relevant drugs. Positive allosteric modulators might represent a promising approach to achieve the potential therapeutic benefits of orthosteric agonists of cannabinoid receptors through increasing their activity and limiting their adverse effects. The aim of the present study was to show the effects of positive allosteric ligands of cannabinoid receptors on the activity of a potent dual orthosteric agonist for neuroinflammation and excitotoxic damage by excessive glutamate release. The results indicate that the combination of an orthosteric agonist with positive allosteric modulators could represent a promising therapeutic approach to the treatment of neurodegenerative disorders.
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13
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Evidence that cannabinoid CB1 receptors regulate intraocular pressure via two opposing mechanisms. Exp Eye Res 2020; 200:108241. [PMID: 32941875 DOI: 10.1016/j.exer.2020.108241] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/30/2020] [Revised: 08/14/2020] [Accepted: 09/08/2020] [Indexed: 11/21/2022]
Abstract
The cannabinoid signaling system regulates intraocular pressure (IOP) in the mouse via a complex system that includes three receptors: CB1, GPR18 and GPR119. In each case, activating the receptor lowers IOP, but CB1 receptors are found both at sites of aqueous humor inflow and outflow. As such, knockout mice for any of these receptors would be expected to have higher-than average, or at least unchanged, intraocular pressure. The current study investigates the unexpected observation that CB1 knockout mice have lower pressure than wild type counterparts by testing various regulators of cannabinoid signaling in murine models of IOP. We now report that a CB1 antagonist has differential effects on IOP: SR141716 raises IOP in standard light cycle (SLC) but lowers IOP in reverse light cycle (RLC). This is mimicked by ABD1085, a negative allosteric modulator of CB1. CB1 inhibitors lower IOP in both normotensive and hypertensive mouse eyes. The pressure-lowering effect is absent in CB1 knockout mice. IOP rebounds after the end of treatment but shows no sign of desensitization with daily treatment for a week. Unlike the positive cannabinoid effect, antagonist effects are not sex-dependent. We propose that there are two mechanisms of action for CB1, one that lowers IOP upon activation and a second with inverse sign that lowers IOP when CB1 is antagonized. The relatively lower pressure in CB1 knockout mouse eyes suggests that this second negative regulation of IOP is dominant.
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14
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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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15
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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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16
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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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17
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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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18
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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: 32] [Impact Index Per Article: 8.0] [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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19
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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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20
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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 DOI: 10.1038/s41401-018-0164-x] [Citation(s) in RCA: 25] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [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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21
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Lafreniere J, Kelly M. Potential for endocannabinoid system modulation in ocular pain and inflammation: filling the gaps in current pharmacological options. Neuronal Signal 2018; 2:NS20170144. [PMID: 32714590 PMCID: PMC7373237 DOI: 10.1042/ns20170144] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/20/2018] [Revised: 10/18/2018] [Accepted: 10/19/2018] [Indexed: 02/06/2023] Open
Abstract
Challenges in the management of ocular pain are an underappreciated topic. Currently available therapeutics lack both efficacy and clear guidelines for their use, with many also possessing unacceptable side effects. Promising novel agents would offer analgesic, anti-inflammatory, and possibly neuroprotective actions; have favorable ocular safety profiles; and show potential in managing neuropathic pain. Growing evidence supports a link between the endocannabinoid system (ECS) and a range of physiological and disease processes, notably those involving inflammation and pain. Both preclinical and clinical data suggest analgesic and anti-inflammatory actions of cannabinoids and ECS-modifying drugs in chronic pain conditions, including those of neuropathic origin. This review will examine existing evidence for the anatomical and physiological basis of ocular pain, specifically, ocular surface disease and the development of chronic ocular pain. The mechanism of action, efficacy, and limitations of currently available treatments will be discussed, and current knowledge related to ECS-modulation of ocular pain and inflammatory disease will be summarized. A perspective will be provided on the future directions of ECS research in terms of developing cannabinoid therapeutics for ocular pain.
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Affiliation(s)
| | - Melanie E.M. Kelly
- Department of Pharmacology, Dalhousie University, Halifax, NS, Canada
- Department of Ophthalmology and Visual Sciences, Dalhousie University, Halifax, NS, Canada
- Department of Anesthesia, Pain Management and Perioperative Medicine, Dalhousie University, Halifax, NS, Canada
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22
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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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23
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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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