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Harding EK, Souza IA, Gandini MA, Gadotti VM, Ali MY, Huang S, Antunes FTT, Trang T, Zamponi GW. Differential regulation of Ca v 3.2 and Ca v 2.2 calcium channels by CB 1 receptors and cannabidiol. Br J Pharmacol 2023; 180:1616-1633. [PMID: 36647671 DOI: 10.1111/bph.16035] [Citation(s) in RCA: 13] [Impact Index Per Article: 13.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/07/2022] [Revised: 12/02/2022] [Accepted: 01/06/2023] [Indexed: 01/18/2023] Open
Abstract
BACKGROUND AND PURPOSE Cannabinoids are a promising therapeutic avenue for chronic pain. However, clinical trials often fail to report analgesic efficacy of cannabinoids. Inhibition of voltage gate calcium (Cav ) channels is one mechanism through which cannabinoids may produce analgesia. We hypothesized that cannabinoids and cannabinoid receptor agonists target different types of Cav channels through distinct mechanisms. EXPERIMENTAL APPROACH Electrophysiological recordings from tsA-201 cells expressing either Cav 3.2 or Cav 2.2 were used to assess inhibition by HU-210 or cannabidiol (CBD) in the absence and presence of the CB1 receptor. Homology modelling assessed potential interaction sites for CBD in both Cav 2.2 and Cav 3.2. Analgesic effects of CBD were assessed in mouse models of inflammatory and neuropathic pain. KEY RESULTS HU-210 (1 μM) inhibited Cav 2.2 function in the presence of CB1 receptor but had no effect on Cav 3.2 regardless of co-expression of CB1 receptor. By contrast, CBD (3 μM) produced no inhibition of Cav 2.2 and instead inhibited Cav 3.2 independently of CB1 receptors. Homology modelling supported these findings, indicating that CBD binds to and occludes the pore of Cav 3.2, but not Cav 2.2. Intrathecal CBD alleviated thermal and mechanical hypersensitivity in both male and female mice, and this effect was absent in Cav 3.2 null mice. CONCLUSION AND IMPLICATIONS Our findings reveal differential modulation of Cav 2.2 and Cav 3.2 channels by CB1 receptors and CBD. This advances our understanding of how different cannabinoids produce analgesia through action at different voltage-gated calcium channels and could influence the development of novel cannabinoid-based therapeutics for treatment of chronic pain.
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Affiliation(s)
- Erika K Harding
- Department of Comparative Biology and Experimental Medicine, University of Calgary, Calgary, AB, Canada.,Department of Clinical Neurosciences, and Physiology & Pharmacology, University of Calgary, Calgary, AB, Canada.,Hotchkiss Brain Institute, University of Calgary, Calgary, AB, Canada
| | - Ivana A Souza
- Department of Clinical Neurosciences, and Physiology & Pharmacology, University of Calgary, Calgary, AB, Canada.,Hotchkiss Brain Institute, University of Calgary, Calgary, AB, Canada
| | - Maria A Gandini
- Department of Clinical Neurosciences, and Physiology & Pharmacology, University of Calgary, Calgary, AB, Canada.,Hotchkiss Brain Institute, University of Calgary, Calgary, AB, Canada
| | - Vinícius M Gadotti
- Department of Clinical Neurosciences, and Physiology & Pharmacology, University of Calgary, Calgary, AB, Canada.,Hotchkiss Brain Institute, University of Calgary, Calgary, AB, Canada.,Zymedyne Therapeutics, Calgary, AB, Canada
| | - Md Yousof Ali
- Department of Clinical Neurosciences, and Physiology & Pharmacology, University of Calgary, Calgary, AB, Canada.,Hotchkiss Brain Institute, University of Calgary, Calgary, AB, Canada.,Zymedyne Therapeutics, Calgary, AB, Canada
| | - Sun Huang
- Department of Clinical Neurosciences, and Physiology & Pharmacology, University of Calgary, Calgary, AB, Canada.,Hotchkiss Brain Institute, University of Calgary, Calgary, AB, Canada
| | - Flavia T T Antunes
- Department of Clinical Neurosciences, and Physiology & Pharmacology, University of Calgary, Calgary, AB, Canada.,Hotchkiss Brain Institute, University of Calgary, Calgary, AB, Canada
| | - Tuan Trang
- Department of Comparative Biology and Experimental Medicine, University of Calgary, Calgary, AB, Canada.,Department of Clinical Neurosciences, and Physiology & Pharmacology, University of Calgary, Calgary, AB, Canada.,Hotchkiss Brain Institute, University of Calgary, Calgary, AB, Canada
| | - Gerald W Zamponi
- Department of Clinical Neurosciences, and Physiology & Pharmacology, University of Calgary, Calgary, AB, Canada.,Hotchkiss Brain Institute, University of Calgary, Calgary, AB, Canada
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Harman T, Udoh M, McElroy DL, Anderson LL, Kevin RC, Banister SD, Ametovski A, Markham J, Bladen C, Doohan PT, Greba Q, Laprairie RB, Snutch TP, McGregor IS, Howland JG, Arnold JC. MEPIRAPIM-derived synthetic cannabinoids inhibit T-type calcium channels with divergent effects on seizures in rodent models of epilepsy. Front Physiol 2023; 14:1086243. [PMID: 37082241 PMCID: PMC10110893 DOI: 10.3389/fphys.2023.1086243] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/01/2022] [Accepted: 03/17/2023] [Indexed: 04/22/2023] Open
Abstract
Background: T-type Ca2+ channels (Cav3) represent emerging therapeutic targets for a range of neurological disorders, including epilepsy and pain. To aid the development and optimisation of new therapeutics, there is a need to identify novel chemical entities which act at these ion channels. A number of synthetic cannabinoid receptor agonists (SCRAs) have been found to exhibit activity at T-type channels, suggesting that cannabinoids may provide convenient chemical scaffolds on which to design novel Cav3 inhibitors. However, activity at cannabinoid type 1 (CB1) receptors can be problematic because of central and peripheral toxicities associated with potent SCRAs. The putative SCRA MEPIRAPIM and its analogues were recently identified as Cav3 inhibitors with only minimal activity at CB1 receptors, opening the possibility that this scaffold may be exploited to develop novel, selective Cav3 inhibitors. Here we present the pharmacological characterisation of SB2193 and SB2193F, two novel Cav3 inhibitors derived from MEPIRAPIM. Methods: The potency of SB2193 and SB2193F was evaluated in vitro using a fluorometric Ca2+ flux assay and confirmed using whole-cell patch-clamp electrophysiology. In silico docking to the cryo-EM structure of Cav3.1 was also performed to elucidate structural insights into T-type channel inhibition. Next, in vivo pharmacokinetic parameters in mouse brain and plasma were determined using liquid chromatography-mass spectroscopy. Finally, anticonvulsant activity was assayed in established genetic and electrically-induced rodent seizure models. Results: Both MEPIRAPIM derivatives produced potent inhibition of Cav3 channels and were brain penetrant, with SB2193 exhibiting a brain/plasma ratio of 2.7. SB2193 was further examined in mouse seizure models where it acutely protected against 6 Hz-induced seizures. However, SB2193 did not reduce spontaneous seizures in the Scn1a +/- mouse model of Dravet syndrome, nor absence seizures in the Genetic Absence Epilepsy Rat from Strasbourg (GAERS). Surprisingly, SB2193 appeared to increase the incidence and duration of spike-and-wave discharges in GAERS animals over a 4 h recording period. Conclusion: These results show that MEPIRAPIM analogues provide novel chemical scaffolds to advance Cav3 inhibitors against certain seizure types.
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Affiliation(s)
- Thomas Harman
- The Lambert Initiative for Cannabinoid Therapeutics, Brain and Mind Centre, The University of Sydney, Sydney, NSW, Australia
- Discipline of Pharmacology, Sydney Pharmacy School, Faculty of Medicine and Health, The University of Sydney, Sydney, NSW, Australia
| | - Michael Udoh
- The Lambert Initiative for Cannabinoid Therapeutics, Brain and Mind Centre, The University of Sydney, Sydney, NSW, Australia
- Discipline of Pharmacology, Sydney Pharmacy School, Faculty of Medicine and Health, The University of Sydney, Sydney, NSW, Australia
| | - Dan L. McElroy
- Department of Anatomy, Physiology and Pharmacology, University of Saskatchewan, Saskatoon, SK, Canada
| | - Lyndsey L. Anderson
- The Lambert Initiative for Cannabinoid Therapeutics, Brain and Mind Centre, The University of Sydney, Sydney, NSW, Australia
- Discipline of Pharmacology, Sydney Pharmacy School, Faculty of Medicine and Health, The University of Sydney, Sydney, NSW, Australia
| | - Richard C. Kevin
- The Lambert Initiative for Cannabinoid Therapeutics, Brain and Mind Centre, The University of Sydney, Sydney, NSW, Australia
- Discipline of Pharmacology, Sydney Pharmacy School, Faculty of Medicine and Health, The University of Sydney, Sydney, NSW, Australia
| | - Samuel D. Banister
- The Lambert Initiative for Cannabinoid Therapeutics, Brain and Mind Centre, The University of Sydney, Sydney, NSW, Australia
- School of Chemistry, Faculty of Science, The University of Sydney, Sydney, NSW, Australia
| | - Adam Ametovski
- The Lambert Initiative for Cannabinoid Therapeutics, Brain and Mind Centre, The University of Sydney, Sydney, NSW, Australia
- School of Chemistry, Faculty of Science, The University of Sydney, Sydney, NSW, Australia
| | - Jack Markham
- The Lambert Initiative for Cannabinoid Therapeutics, Brain and Mind Centre, The University of Sydney, Sydney, NSW, Australia
- School of Chemistry, Faculty of Science, The University of Sydney, Sydney, NSW, Australia
| | - Chris Bladen
- Department of Biomedical Sciences, Macquarie University, Sydney, NSW, Australia
| | - Peter T. Doohan
- The Lambert Initiative for Cannabinoid Therapeutics, Brain and Mind Centre, The University of Sydney, Sydney, NSW, Australia
- Discipline of Pharmacology, Sydney Pharmacy School, Faculty of Medicine and Health, The University of Sydney, Sydney, NSW, Australia
| | - Quentin Greba
- Department of Anatomy, Physiology and Pharmacology, University of Saskatchewan, Saskatoon, SK, Canada
| | - Robert B. Laprairie
- College of Pharmacy and Nutrition, University of Saskatchewan, Saskatoon, SK, Canada
| | - Terrance P. Snutch
- Michael Smith Laboratories and Djavad Mowafaghian Centre for Brain Health, University of British Columbia, Vancouver, BC, Canada
| | - Iain S. McGregor
- The Lambert Initiative for Cannabinoid Therapeutics, Brain and Mind Centre, The University of Sydney, Sydney, NSW, Australia
- School of Psychology, Faculty of Science, The University of Sydney, Sydney, NSW, Australia
| | - John G. Howland
- Department of Anatomy, Physiology and Pharmacology, University of Saskatchewan, Saskatoon, SK, Canada
| | - Jonathon C. Arnold
- The Lambert Initiative for Cannabinoid Therapeutics, Brain and Mind Centre, The University of Sydney, Sydney, NSW, Australia
- Discipline of Pharmacology, Sydney Pharmacy School, Faculty of Medicine and Health, The University of Sydney, Sydney, NSW, Australia
- *Correspondence: Jonathon C. Arnold,
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Markham J, Sparkes E, Boyd R, Chen S, Manning JJ, Finlay D, Lai F, McGregor E, Maloney CJ, Gerona RR, Connor M, McGregor IS, Hibbs DE, Glass M, Kevin RC, Banister SD. Defining Steric Requirements at CB 1 and CB 2 Cannabinoid Receptors Using Synthetic Cannabinoid Receptor Agonists 5F-AB-PINACA, 5F-ADB-PINACA, PX-1, PX-2, NNL-1, and Their Analogues. ACS Chem Neurosci 2022; 13:1281-1295. [PMID: 35404067 DOI: 10.1021/acschemneuro.2c00034] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022] Open
Abstract
Synthetic cannabinoid receptor agonists (SCRAs) are a diverse class of new psychoactive substances (NPS). They commonly comprise N-alkylated indole, indazole, or 7-azaindole scaffolds with amide-linked pendant amino acid groups. To explore the contribution of the amino acid side chain to the cannabinoid pharmacology of SCRA NPS, a systematic library of side chain-modified SCRAs was prepared based on the recent detections of amino acid derivatives 17 (5F-AB-PINACA), 18 (5F-ADB-PINACA), 15 (PX-1), 19 (PX-2), and 20 (NNL-1). In vitro binding affinities and functional activities at cannabinoid type 1 and 2 receptors (CB1 and CB2, respectively) were determined for all the library members using radioligand competition experiments and a fluorescence-based membrane potential assay. Binding affinities and functional activities varied widely across compounds (Ki = 0.32 to >10 000 nM, EC50 = 0.24-1259 nM), with several clear structure-activity relationships (SARs) emerging. Affinity and potency at CB1 changed as a function of the heterocyclic core (indazole > indole > 7-azaindole) and the pendant amino acid side chain (tert-butyl > iso-propyl > iso-butyl > benzyl > ethyl > methyl > hydrogen). Ensemble docking at CB1 revealed a clear steric basis for observed SAR trends. Interestingly, although 15 (PX-1) and 19 (PX-2) have been detected in recreational drug markets, they failed to induce centrally CB1-mediated effects (e.g., hypothermia) in mice using radiobiotelemetry. Together, these data provide insights regarding structural contributions to the cannabimimetic profiles of 17 (5F-AB-PINACA), 18 (5F-ADB-PINACA), 15 (PX-1), 19 (PX-2), 20 (NNL-1), and other SCRA NPS.
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Affiliation(s)
- Jack Markham
- The Lambert Initiative for Cannabinoid Therapeutics, Brain and Mind Centre, The University of Sydney, Sydney 2050, New South Wales, Australia
- School of Chemistry, The University of Sydney, Sydney 2006, New South Wales, Australia
| | - Eric Sparkes
- The Lambert Initiative for Cannabinoid Therapeutics, Brain and Mind Centre, The University of Sydney, Sydney 2050, New South Wales, Australia
- School of Chemistry, The University of Sydney, Sydney 2006, New South Wales, Australia
| | - Rochelle Boyd
- The Lambert Initiative for Cannabinoid Therapeutics, Brain and Mind Centre, The University of Sydney, Sydney 2050, New South Wales, Australia
- School of Chemistry, The University of Sydney, Sydney 2006, New South Wales, Australia
| | - Shuli Chen
- Department of Pharmacology and Toxicology, University of Otago, Dunedin 9016, New Zealand
| | - Jamie J. Manning
- Department of Pharmacology and Toxicology, University of Otago, Dunedin 9016, New Zealand
| | - David Finlay
- Department of Pharmacology and Toxicology, University of Otago, Dunedin 9016, New Zealand
| | - Felcia Lai
- School of Pharmacy, The University of Sydney, Sydney 2006, New South Wales, Australia
| | - Eila McGregor
- The Lambert Initiative for Cannabinoid Therapeutics, Brain and Mind Centre, The University of Sydney, Sydney 2050, New South Wales, Australia
- School of Psychology, The University of Sydney, Sydney 2005, New South Wales, Australia
| | - Callan J. Maloney
- The Lambert Initiative for Cannabinoid Therapeutics, Brain and Mind Centre, The University of Sydney, Sydney 2050, New South Wales, Australia
- School of Chemistry, The University of Sydney, Sydney 2006, New South Wales, Australia
| | - Roy R. Gerona
- Clinical Toxicology and Environmental Biomonitoring Laboratory, University of California, San Francisco, California 94143, United States
| | - Mark Connor
- Faculty of Medicine and Health Sciences, Macquarie University, Sydney 2109, New South Wales, Australia
| | - Iain S. McGregor
- The Lambert Initiative for Cannabinoid Therapeutics, Brain and Mind Centre, The University of Sydney, Sydney 2050, New South Wales, Australia
- School of Psychology, The University of Sydney, Sydney 2005, New South Wales, Australia
| | - David E. Hibbs
- School of Pharmacy, The University of Sydney, Sydney 2006, New South Wales, Australia
| | - Michelle Glass
- Department of Pharmacology and Toxicology, University of Otago, Dunedin 9016, New Zealand
| | - Richard C. Kevin
- The Lambert Initiative for Cannabinoid Therapeutics, Brain and Mind Centre, The University of Sydney, Sydney 2050, New South Wales, Australia
- School of Pharmacy, The University of Sydney, Sydney 2006, New South Wales, Australia
| | - Samuel D. Banister
- The Lambert Initiative for Cannabinoid Therapeutics, Brain and Mind Centre, The University of Sydney, Sydney 2050, New South Wales, Australia
- School of Chemistry, The University of Sydney, Sydney 2006, New South Wales, Australia
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Kevin RC, Cairns EA, Boyd R, Arnold JC, Bowen MT, McGregor IS, Banister SD. Off-target pharmacological profiling of synthetic cannabinoid receptor agonists including AMB-FUBINACA, CUMYL-PINACA, PB-22, and XLR-11. Front Psychiatry 2022; 13:1048836. [PMID: 36590635 PMCID: PMC9798004 DOI: 10.3389/fpsyt.2022.1048836] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 09/20/2022] [Accepted: 11/23/2022] [Indexed: 12/23/2022] Open
Abstract
INTRODUCTION Synthetic cannabinoid receptor agonists (SCRAs) are a diverse class of new psychoactive substances that have been associated with multiple instances and types of toxicity. Some SCRAs appear to carry a greater toxicological burden than others, or compared to the prototypical cannabis-derived agonist Δ9-tetrahydrocannabinol (Δ9-THC), despite a common primary mechanism of action via cannabinoid 1 (CB1) receptors. "Off-target" (i.e., non-CB1 receptor) effects could underpin this differential toxicity, although there are limited data around the activity of SCRAs at such targets. METHODS A selection of 7 SCRAs (AMB-FUBINACA, XLR11, PB-22, AKB-48, AB-CHMINICA, CUMYL-PINACA, and 4F-MDMB-BUTINACA), representing several distinct chemotypes and toxicological profiles, underwent a 30 μM single-point screen against 241 G protein-coupled receptor (GPCR) targets in antagonist and agonist mode using a cellular β-arrestin recruitment assay. Strong screening "hits" at specific GPCRs were followed up in detail using concentration-response assays with AMB-FUBINACA, a SCRA with a particularly notable history of toxicological liability. RESULTS The single-point screen yielded few hits in agonist mode for any compound aside from CB1 and CB2 receptors, but many hits in antagonist mode, including a range of chemokine receptors, the oxytocin receptor, and histamine receptors. Concentration-response experiments showed that AMB-FUBINACA inhibited most off-targets only at the highest 30 μM concentration, with inhibition of only a small subset of targets, including H1 histamine and α2B adrenergic receptors, at lower concentrations (≥1 μM). AMB-FUBINACA also produced concentration-dependent CB1 receptor signaling disruption at concentrations higher than 1 μM, but did not produce overt cytotoxicity beyond CP55,940 or Δ9-THC in CB1 expressing cells. DISCUSSION These results suggest that while some "off-targets" could possibly contribute to the SCRA toxidrome, particularly at high concentrations, CB1-mediated cellular dysfunction provides support for hypotheses concerning on-target, rather than off-target, toxicity. Further investigation of non-GPCR off-targets is warranted.
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Affiliation(s)
- Richard C Kevin
- The Lambert Initiative for Cannabinoid Therapeutics, The University of Sydney, Camperdown, NSW, Australia.,School of Pharmacy, The University of Sydney, Camperdown, NSW, Australia
| | - Elizabeth A Cairns
- The Lambert Initiative for Cannabinoid Therapeutics, The University of Sydney, Camperdown, NSW, Australia.,School of Psychology, The University of Sydney, Camperdown, NSW, Australia
| | - Rochelle Boyd
- The Lambert Initiative for Cannabinoid Therapeutics, The University of Sydney, Camperdown, NSW, Australia.,School of Psychology, The University of Sydney, Camperdown, NSW, Australia
| | - Jonathon C Arnold
- The Lambert Initiative for Cannabinoid Therapeutics, The University of Sydney, Camperdown, NSW, Australia.,School of Pharmacy, The University of Sydney, Camperdown, NSW, Australia
| | - Michael T Bowen
- School of Psychology, The University of Sydney, Camperdown, NSW, Australia.,Brain and Mind Centre, The University of Sydney, Camperdown, NSW, Australia
| | - Iain S McGregor
- The Lambert Initiative for Cannabinoid Therapeutics, The University of Sydney, Camperdown, NSW, Australia.,School of Psychology, The University of Sydney, Camperdown, NSW, Australia
| | - Samuel D Banister
- The Lambert Initiative for Cannabinoid Therapeutics, The University of Sydney, Camperdown, NSW, Australia.,School of Chemistry, The University of Sydney, Camperdown, NSW, Australia
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