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Flavin A, Azizi P, Murataeva N, Yust K, Du W, Ross R, Greig I, Nguyen T, Zhang Y, Mackie K, Straiker A. CB1 Receptor Negative Allosteric Modulators as a Potential Tool to Reverse Cannabinoid Toxicity. Molecules 2024; 29:1881. [PMID: 38675703 PMCID: PMC11053441 DOI: 10.3390/molecules29081881] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/01/2024] [Revised: 04/11/2024] [Accepted: 04/15/2024] [Indexed: 04/28/2024] Open
Abstract
While the opioid crisis has justifiably occupied news headlines, emergency rooms are seeing many thousands of visits for another cause: cannabinoid toxicity. This is partly due to the spread of cheap and extremely potent synthetic cannabinoids that can cause serious neurological and cardiovascular complications-and deaths-every year. While an opioid overdose can be reversed by naloxone, there is no analogous treatment for cannabis toxicity. Without an antidote, doctors rely on sedatives, with their own risks, or 'waiting it out' to treat these patients. We have shown that the canonical synthetic 'designer' cannabinoids are highly potent CB1 receptor agonists and, as a result, competitive antagonists may struggle to rapidly reverse an overdose due to synthetic cannabinoids. Negative allosteric modulators (NAMs) have the potential to attenuate the effects of synthetic cannabinoids without having to directly compete for binding. We tested a group of CB1 NAMs for their ability to reverse the effects of the canonical synthetic designer cannabinoid JWH018 in vitro in a neuronal model of endogenous cannabinoid signaling and also in vivo. We tested ABD1085, RTICBM189, and PSNCBAM1 in autaptic hippocampal neurons that endogenously express a retrograde CB1-dependent circuit that inhibits neurotransmission. We found that all of these compounds blocked/reversed JWH018, though some proved more potent than others. We then tested whether these compounds could block the effects of JWH018 in vivo, using a test of nociception in mice. We found that only two of these compounds-RTICBM189 and PSNCBAM1-blocked JWH018 when applied in advance. The in vitro potency of a compound did not predict its in vivo potency. PSNCBAM1 proved to be the more potent of the compounds and also reversed the effects of JWH018 when applied afterward, a condition that more closely mimics an overdose situation. Lastly, we found that PSNCBAM1 did not elicit withdrawal after chronic JWH018 treatment. In summary, CB1 NAMs can, in principle, reverse the effects of the canonical synthetic designer cannabinoid JWH018 both in vitro and in vivo, without inducing withdrawal. These findings suggest a novel pharmacological approach to at last provide a tool to counter cannabinoid toxicity.
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Affiliation(s)
- Audrey Flavin
- Gill Center for Biomolecular Science, Program in Neuroscience, Department of Psychological and Brain Sciences Indiana University, Bloomington, IN 47405, USA (N.M.); (K.Y.); (W.D.); (K.M.)
| | - Paniz Azizi
- Gill Center for Biomolecular Science, Program in Neuroscience, Department of Psychological and Brain Sciences Indiana University, Bloomington, IN 47405, USA (N.M.); (K.Y.); (W.D.); (K.M.)
| | - Natalia Murataeva
- Gill Center for Biomolecular Science, Program in Neuroscience, Department of Psychological and Brain Sciences Indiana University, Bloomington, IN 47405, USA (N.M.); (K.Y.); (W.D.); (K.M.)
| | - Kyle Yust
- Gill Center for Biomolecular Science, Program in Neuroscience, Department of Psychological and Brain Sciences Indiana University, Bloomington, IN 47405, USA (N.M.); (K.Y.); (W.D.); (K.M.)
| | - Wenwen Du
- Gill Center for Biomolecular Science, Program in Neuroscience, Department of Psychological and Brain Sciences Indiana University, Bloomington, IN 47405, USA (N.M.); (K.Y.); (W.D.); (K.M.)
| | - Ruth Ross
- Department of Pharmacology and Toxicology, University of Toronto, Toronto, ON M5G 2C8, Canada;
| | - Iain Greig
- Institute of Medical Sciences, University of Aberdeen, Aberdeen AB25 2ZD, UK;
| | - Thuy Nguyen
- Research Triangle Institute, Durham, NC 27709, USA; (T.N.); (Y.Z.)
| | - Yanan Zhang
- Research Triangle Institute, Durham, NC 27709, USA; (T.N.); (Y.Z.)
| | - Ken Mackie
- Gill Center for Biomolecular Science, Program in Neuroscience, Department of Psychological and Brain Sciences Indiana University, Bloomington, IN 47405, USA (N.M.); (K.Y.); (W.D.); (K.M.)
| | - Alex Straiker
- Gill Center for Biomolecular Science, Program in Neuroscience, Department of Psychological and Brain Sciences Indiana University, Bloomington, IN 47405, USA (N.M.); (K.Y.); (W.D.); (K.M.)
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Abstract
Purpose Aqueous deficiency dry eye (ADDE) is a chronic condition affecting millions, with symptoms ranging from a dry itchiness to blurred vision and accompanied by an increased risk of eye infections. ADDE typically arises from disorders of the lacrimal gland that produces tears necessary for eye lubrication. Cannabis users frequently report dry eye, but the basis for this is unknown. If the effects occur via the endogenous cannabinoid signaling system, then this may represent a novel mechanism for the regulation of tearing. Methods We examined expression of cannabinoid CB1 receptors in the lacrimal gland using immunohistochemistry, Western blotting, and PCR and tested tetrahydrocannabinol (THC) regulation of tearing in wild-type and CB1-null mice. Results We now report that CB1 receptors are expressed in the axons of cholinergic neurons innervating the lacrimal gland. Little if any staining is seen in lacrimal gland epithelial cells (acinar and ductal) or myoepithelial cells (MECs). Activation of CB1 receptors by THC or the cannabinoid agonist CP55940 reduces tearing in male mice. In female mice, THC has no effect, but CP55940 increases tearing. In both sexes, the effect of CP55940 is absent in CB1 knockout mice. CB1 mRNA and protein levels are approximately four- to fivefold higher in males than females. In male knockouts, THC increases tearing, suggesting that THC also acts through different receptors. Conclusions Our results suggest a novel, albeit sex-dependent, physiologic basis for the dry eye symptoms experienced by cannabis users: activation of neuronal CB1 receptors in the lacrimal gland reduces tearing.
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Affiliation(s)
- Amanda Thayer
- The Gill Center for Biomolecular Science, Indiana University, Bloomington, Indiana, United States.,Department of Psychological and Brain Sciences, Indiana University, Bloomington, Indiana, United States
| | - Natalia Murataeva
- The Gill Center for Biomolecular Science, Indiana University, Bloomington, Indiana, United States.,Department of Psychological and Brain Sciences, Indiana University, Bloomington, Indiana, United States
| | - Vanessa Delcroix
- Scripps Research Institute, Department of Molecular Medicine, La Jolla, California, United States
| | - Jim Wager-Miller
- The Gill Center for Biomolecular Science, Indiana University, Bloomington, Indiana, United States.,Department of Psychological and Brain Sciences, Indiana University, Bloomington, Indiana, United States
| | - Helen P Makarenkova
- Scripps Research Institute, Department of Molecular Medicine, La Jolla, California, United States
| | - Alex Straiker
- The Gill Center for Biomolecular Science, Indiana University, Bloomington, Indiana, United States.,Department of Psychological and Brain Sciences, Indiana University, Bloomington, Indiana, United States.,Program in Neuroscience, Indiana University, Bloomington, Indiana, United States
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Murataeva N, Miller S, Dhopeshwarkar A, Leishman E, Daily L, Taylor X, Morton B, Lashmet M, Bradshaw H, Hillard CJ, Romero J, Straiker A. Cannabinoid CB2R receptors are upregulated with corneal injury and regulate the course of corneal wound healing. Exp Eye Res 2019; 182:74-84. [PMID: 30905716 DOI: 10.1016/j.exer.2019.03.011] [Citation(s) in RCA: 20] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/13/2018] [Revised: 01/22/2019] [Accepted: 03/17/2019] [Indexed: 12/12/2022]
Abstract
CB2R receptors have demonstrated beneficial effects in wound healing in several models. We therefore investigated a potential role of CB2R receptors in corneal wound healing. We examined the functional contribution of CB2R receptors to the course of wound closure in an in vivo murine model. We additionally examined corneal expression of CB2R receptors in mouse and the consequences of their activation on cellular signaling, migration and proliferation in cultured bovine corneal epithelial cells (CECs). Using a novel mouse model, we provide evidence that corneal injury increases CB2R receptor expression in cornea. The CB2R agonist JWH133 induces chemorepulsion in cultured bovine CECs but does not alter CEC proliferation. The signaling profile of CB2R activation is activating MAPK and increasing cAMP accumulation, the latter perhaps due to Gs-coupling. Lipidomic analysis in bovine cornea shows a rise in acylethanolamines including the endocannabinoid anandamide 1 h after injury. In vivo, CB2R deletion and pharmacological block result in a delayed course of wound closure. In summary, we find evidence that CB2R receptor promoter activity is increased by corneal injury and that these receptors are required for the normal course of wound closure, possibly via chemorepulsion.
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Affiliation(s)
- Natalia Murataeva
- The Gill Center for Biomolecular Science and the Department of Psychological and Brain Sciences, Indiana University, Bloomington, IN, 47405, USA
| | - Sally Miller
- The Gill Center for Biomolecular Science and the Department of Psychological and Brain Sciences, Indiana University, Bloomington, IN, 47405, USA
| | - Amey Dhopeshwarkar
- The Gill Center for Biomolecular Science and the Department of Psychological and Brain Sciences, Indiana University, Bloomington, IN, 47405, USA
| | - Emma Leishman
- The Gill Center for Biomolecular Science and the Department of Psychological and Brain Sciences, Indiana University, Bloomington, IN, 47405, USA
| | - Laura Daily
- The Gill Center for Biomolecular Science and the Department of Psychological and Brain Sciences, Indiana University, Bloomington, IN, 47405, USA
| | - Xavier Taylor
- The Gill Center for Biomolecular Science and the Department of Psychological and Brain Sciences, Indiana University, Bloomington, IN, 47405, USA
| | - Brian Morton
- The Gill Center for Biomolecular Science and the Department of Psychological and Brain Sciences, Indiana University, Bloomington, IN, 47405, USA
| | - Matthew Lashmet
- The Gill Center for Biomolecular Science and the Department of Psychological and Brain Sciences, Indiana University, Bloomington, IN, 47405, USA
| | - Heather Bradshaw
- The Gill Center for Biomolecular Science and the Department of Psychological and Brain Sciences, Indiana University, Bloomington, IN, 47405, USA
| | - Cecilia J Hillard
- Department of Pharmacology and Toxicology, Neuroscience Research Center, Medical College of Wisconsin, Milwaukee, WI, USA
| | - Julian Romero
- Faculty of Experimental Sciences, Universidad Francisco de Vitoria, Pozuelo de Alarcón, 28223, Madrid, Spain
| | - Alex Straiker
- The Gill Center for Biomolecular Science and the Department of Psychological and Brain Sciences, Indiana University, Bloomington, IN, 47405, USA.
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Borowska-Fielding J, Murataeva N, Smith B, Szczesniak AM, Leishman E, Daily L, Toguri JT, Hillard CJ, Romero J, Bradshaw H, Kelly MEM, Straiker A. Revisiting cannabinoid receptor 2 expression and function in murine retina. Neuropharmacology 2018; 141:21-31. [PMID: 30121200 DOI: 10.1016/j.neuropharm.2018.08.007] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/06/2018] [Revised: 07/15/2018] [Accepted: 08/05/2018] [Indexed: 01/12/2023]
Abstract
The cannabinoid receptor CB2 plays a significant role in the regulation of immune function whereas neuronal expression remains a subject of contention. Multiple studies have described CB2 in retina and a recent study showed that CB2 deletion altered retinal visual processing. We revisited CB2 expression using immunohistochemistry and a recently developed CB2-eGFP reporter mouse. We examined the consequence of acute vs. prolonged CB2 deactivation on the electroretinogram (ERG) responses. We also examined lipidomics in CB2 knockout mice and potential changes in microglia using Scholl analysis. Consistent with a published report, in CB2 receptor knockout mice see an increased ERG scotopic a-wave, as well as stronger responses in dark adapted cone-driven ON bipolar cells and, to a lesser extent cone-driven ON bipolar cells early in light adaptation. Significantly, however, acute block with CB2 antagonist, AM630, did not mimic the results observed in the CB2 knockout mice whereas chronic (7 days) block did. Immunohistochemical studies show no CB2 in retina under non-pathological conditions, even with published antibodies. Retinal CB2-eGFP reporter signal is minimal under baseline conditions but upregulated by intraocular injection of either LPS or carrageenan. CB2 knockout mice see modest declines in a broad spectrum of cannabinoid-related lipids. The numbers and morphology of microglia were unaltered. In summary minimal CB2 expression is seen in healthy retina. CB2 appears to be upregulated under pathological conditions. Previously reported functional consequences of CB2 deletion are an adaptive response to prolonged blockade of these receptors. CB2 therefore impacts retinal signaling but perhaps in an indirect, potentially extra-ocular fashion.
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Affiliation(s)
| | - Natalia Murataeva
- Department of Psychological and Brain Sciences, Gill Center for Biomolecular Science, Indiana University, Bloomington, IN, USA
| | - Ben Smith
- Physiology and Biophysics, Dalhousie University, Halifax, NS, Canada
| | | | - Emma Leishman
- Department of Psychological and Brain Sciences, Gill Center for Biomolecular Science, Indiana University, Bloomington, IN, USA
| | - Laura Daily
- Department of Psychological and Brain Sciences, Gill Center for Biomolecular Science, Indiana University, Bloomington, IN, USA
| | - J Thomas Toguri
- Department of Pharmacology, Dalhousie University, Halifax, NS, Canada
| | - Cecelia J Hillard
- Department of Pharmacology and Toxicology, Medical College of Wisconsin, Milwaukee, WI, USA
| | - Julian Romero
- Faculty of Experimental Sciences, Universidad Francisco de Vitoria, Pozuelo de Alarcón, 28223, Madrid, Spain
| | - Heather Bradshaw
- Department of Psychological and Brain Sciences, Gill Center for Biomolecular Science, Indiana University, Bloomington, IN, USA
| | - Melanie E M Kelly
- Department of Pharmacology, Dalhousie University, Halifax, NS, Canada; Physiology and Biophysics, Dalhousie University, Halifax, NS, Canada; Anesthesia, Dalhousie University, Halifax, NS, Canada
| | - Alex Straiker
- Department of Psychological and Brain Sciences, Gill Center for Biomolecular Science, Indiana University, Bloomington, IN, USA.
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Miller S, Leishman E, Oehler O, Daily L, Murataeva N, Wager-Miller J, Bradshaw H, Straiker A. Evidence for a GPR18 Role in Diurnal Regulation of Intraocular Pressure. Invest Ophthalmol Vis Sci 2017; 57:6419-6426. [PMID: 27893106 PMCID: PMC5132083 DOI: 10.1167/iovs.16-19437] [Citation(s) in RCA: 28] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/24/2022] Open
Abstract
Purpose The diurnal cycling of intraocular pressure (IOP) was first described in humans more than a century ago. This cycling is preserved in other species. The physiologic underpinning of this diurnal variation in IOP remains a mystery, even though elevated pressure is indicated in most forms of glaucoma, a common cause of blindness. Once identified, the system that underlies diurnal variation would represent a natural target for therapeutic intervention. Methods Using normotensive mice, we measured the regulation of ocular lipid species by the enzymes fatty acid amide hydrolase (FAAH) and N-arachidonoyl phosphatidylethanolamine phospholipase (NAPE-PLD), mRNA expression of these enzymes, and their functional role in diurnal regulation of IOP. Results We now report that NAPE-PLD and FAAH mice do not exhibit a diurnal cycling of IOP. These enzymes produce and break down acylethanolamines, including the endogenous cannabinoid anandamide. The diurnal lipid profile in mice shows that levels of most N-acyl ethanolamines and, intriguingly, N-arachidonoyl glycine (NAGly), decline at night: NAGly is a metabolite of arachidonoyl ethanolamine and a potent agonist at GPR18 that lowers intraocular pressure. The GPR18 blocker O1918 raises IOP during the day when pressure is low, but not at night. Quantitative PCR analysis shows that FAAH mRNA levels rise with pressure, suggesting that FAAH mediates the changes in pressure. Conclusions Our results support FAAH-dependent NAGly action at GPR18 as the physiologic basis of the diurnal variation of intraocular pressure in mice.
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Affiliation(s)
- Sally Miller
- The Gill Center for Biomolecular Science and the Department of Psychological and Brain Sciences, Indiana University, Bloomington, Indiana, United States
| | - Emma Leishman
- The Gill Center for Biomolecular Science and the Department of Psychological and Brain Sciences, Indiana University, Bloomington, Indiana, United States
| | - Olivia Oehler
- The Gill Center for Biomolecular Science and the Department of Psychological and Brain Sciences, Indiana University, Bloomington, Indiana, United States
| | - Laura Daily
- The Gill Center for Biomolecular Science and the Department of Psychological and Brain Sciences, Indiana University, Bloomington, Indiana, United States
| | - Natalia Murataeva
- The Gill Center for Biomolecular Science and the Department of Psychological and Brain Sciences, Indiana University, Bloomington, Indiana, United States
| | - Jim Wager-Miller
- The Gill Center for Biomolecular Science and the Department of Psychological and Brain Sciences, Indiana University, Bloomington, Indiana, United States
| | - Heather Bradshaw
- The Gill Center for Biomolecular Science and the Department of Psychological and Brain Sciences, Indiana University, Bloomington, Indiana, United States
| | - Alex Straiker
- The Gill Center for Biomolecular Science and the Department of Psychological and Brain Sciences, Indiana University, Bloomington, Indiana, United States
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Miller S, Leishman E, Hu SS, Elghouche A, Daily L, Murataeva N, Bradshaw H, Straiker A. Harnessing the Endocannabinoid 2-Arachidonoylglycerol to Lower Intraocular Pressure in a Murine Model. Invest Ophthalmol Vis Sci 2017; 57:3287-96. [PMID: 27333182 PMCID: PMC4961057 DOI: 10.1167/iovs.16-19356] [Citation(s) in RCA: 22] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/24/2023] Open
Abstract
Purpose Cannabinoids, such as Δ9-THC, act through an endogenous signaling system in the vertebrate eye that reduces IOP via CB1 receptors. Endogenous cannabinoid (eCB) ligand, 2-arachidonoyl glycerol (2-AG), likewise activates CB1 and is metabolized by monoacylglycerol lipase (MAGL). We investigated ocular 2-AG and its regulation by MAGL and the therapeutic potential of harnessing eCBs to lower IOP. Methods We tested the effect of topical application of 2-AG and MAGL blockers in normotensive mice and examined changes in eCB-related lipid species in the eyes and spinal cord of MAGL knockout (MAGL−/−) mice using high performance liquid chromatography/tandem mass spectrometry (HPLC/MS/MS). We also examined the protein distribution of MAGL in the mouse anterior chamber. Results 2-Arachidonoyl glycerol reliably lowered IOP in a CB1- and concentration-dependent manner. Monoacylglycerol lipase is expressed prominently in nonpigmented ciliary epithelium. The MAGL blocker KML29, but not JZL184, lowered IOP. The ability of CB1 to lower IOP is not desensitized in MAGL−/− mice. Ocular monoacylglycerols, including 2-AG, are elevated in MAGL−/− mice but, in contrast to the spinal cord, arachidonic acid and prostaglandins are not changed. Conclusions Our data confirm a central role for MAGL in metabolism of ocular 2-AG and related lipid species, and that endogenous 2-AG can be harnessed to reduce IOP. The MAGL blocker KML29 has promise as a therapeutic agent, while JZL184 may have difficulty crossing the cornea. These data, combined with the relative specificity of MAGL for ocular monoacylglycerols and the lack of desensitization in MAGL−/− mice, suggest that the development of an optimized MAGL blocker offers therapeutic potential for treatment of elevated IOP.
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Affiliation(s)
- Sally Miller
- Department of Psychological and Brain Sciences Indiana University, Bloomington, Indiana, United States
| | - Emma Leishman
- Department of Psychological and Brain Sciences Indiana University, Bloomington, Indiana, United States
| | - Sherry Shujung Hu
- Department of Psychology, National Cheng Kung University, Tainan, Taiwan
| | - Alhasan Elghouche
- Department of Psychological and Brain Sciences Indiana University, Bloomington, Indiana, United States
| | - Laura Daily
- Department of Psychological and Brain Sciences Indiana University, Bloomington, Indiana, United States
| | - Natalia Murataeva
- Department of Psychological and Brain Sciences Indiana University, Bloomington, Indiana, United States
| | - Heather Bradshaw
- Department of Psychological and Brain Sciences Indiana University, Bloomington, Indiana, United States
| | - Alex Straiker
- Department of Psychological and Brain Sciences Indiana University, Bloomington, Indiana, United States
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Dhopeshwarkar A, Murataeva N, Makriyannis A, Straiker A, Mackie K. Two Janus Cannabinoids That Are Both CB2 Agonists and CB1 Antagonists. J Pharmacol Exp Ther 2016; 360:300-311. [PMID: 27927913 DOI: 10.1124/jpet.116.236539] [Citation(s) in RCA: 19] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/13/2016] [Accepted: 12/05/2016] [Indexed: 01/24/2023] Open
Abstract
The cannabinoid signaling system includes two G protein-coupled receptors, CB1 and CB2 These receptors are widely distributed throughout the body and have each been implicated in many physiologically important processes. Although the cannabinoid signaling system has therapeutic potential, the development of receptor-selective ligands remains a persistent hurdle. Because CB1 and CB2 are involved in diverse processes, it would be advantageous to develop ligands that differentially engage CB1 and CB2 We now report that GW405833 [1-(2,3-dichlorobenzoyl)-5-methoxy-2-methyl-3-[2-(4-morpholinyl)ethyl]-1H-indole] and AM1710 [1-hydroxy-9-methoxy-3-(2-methyloctan-2-yl)benzo[c]chromen-6-one], described as selective CB2 agonists, can antagonize CB1 receptor signaling. In autaptic hippocampal neurons, GW405833 and AM1710 both interfered with CB1-mediated depolarization-induced suppression of excitation, with GW405833 being more potent. In addition, in CB1-expressing human embryonic kidney 293 cells, GW405833 noncompetitively antagonized adenylyl cyclase activity, extracellular signal-regulated kinase 1/2 phosphorylation, phosphatidylinositol 4,5-bisphosphate signaling, and CB1 internalization by CP55940 (2-[(1R,2R,5R)-5-hydroxy-2-(3-hydroxypropyl)cyclohexyl]-5-(2-methyloctan-2-yl)phenol). In contrast, AM1710 behaved as a low-potency competitive antagonist/inverse agonist in these signaling pathways. GW405833 interactions with CB1/arrestin signaling were complex: GW405833 differentially modulated arrestin recruitment in a time-dependent fashion, with an initial modest potentiation at 20 minutes followed by antagonism starting at 1 hour. AM1710 acted as a low-efficacy agonist in arrestin signaling at the CB1 receptor, with no evident time dependence. In summary, we determined that GW405833 and AM1710 are not only CB2 agonists but also CB1 antagonists, with distinctive and complex signaling properties. Thus, experiments using these compounds must take into account their potential activity at CB1 receptors.
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Affiliation(s)
- Amey Dhopeshwarkar
- Department of Psychological and Brain Sciences, Gill Center for Biomolecular Science, Indiana University, Bloomington, Indiana (A.D., N.M., A.S., K.M.); and Department of Pharmaceutical Sciences, Center for Drug Discovery, Northeastern University, Boston, Massachusetts (A.M.)
| | - Natalia Murataeva
- Department of Psychological and Brain Sciences, Gill Center for Biomolecular Science, Indiana University, Bloomington, Indiana (A.D., N.M., A.S., K.M.); and Department of Pharmaceutical Sciences, Center for Drug Discovery, Northeastern University, Boston, Massachusetts (A.M.)
| | - Alex Makriyannis
- Department of Psychological and Brain Sciences, Gill Center for Biomolecular Science, Indiana University, Bloomington, Indiana (A.D., N.M., A.S., K.M.); and Department of Pharmaceutical Sciences, Center for Drug Discovery, Northeastern University, Boston, Massachusetts (A.M.)
| | - Alex Straiker
- Department of Psychological and Brain Sciences, Gill Center for Biomolecular Science, Indiana University, Bloomington, Indiana (A.D., N.M., A.S., K.M.); and Department of Pharmaceutical Sciences, Center for Drug Discovery, Northeastern University, Boston, Massachusetts (A.M.)
| | - Ken Mackie
- Department of Psychological and Brain Sciences, Gill Center for Biomolecular Science, Indiana University, Bloomington, Indiana (A.D., N.M., A.S., K.M.); and Department of Pharmaceutical Sciences, Center for Drug Discovery, Northeastern University, Boston, Massachusetts (A.M.)
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Murataeva N, Dhopeshwarkar A, Yin D, Mitjavila J, Bradshaw H, Straiker A, Mackie K. Where's my entourage? The curious case of 2-oleoylglycerol, 2-linolenoylglycerol, and 2-palmitoylglycerol. Pharmacol Res 2016; 110:173-180. [PMID: 27117667 DOI: 10.1016/j.phrs.2016.04.015] [Citation(s) in RCA: 26] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 01/09/2016] [Revised: 04/18/2016] [Accepted: 04/19/2016] [Indexed: 10/21/2022]
Abstract
2-Arachidonoylglycerol (2-AG) is the most abundant endogenous cannabinoid in the brain and an agonist at two cannabinoid receptors (CB1 and CB2). The synthesis, degradation and signaling of 2-AG have been investigated in detail but its relationship to other endogenous monoacylglycerols has not been fully explored. Three congeners that have been isolated from the CNS are 2-linoleoylglycerol (2-LG), 2-oleoylglycerol (2-OG), and 2-palmitoylglycerol (2-PG). These lipids do not orthosterically bind to cannabinoid receptors but are reported to potentiate the activity of 2-AG, possibly through inhibition of 2-AG degradation. This phenomenon has been dubbed the 'entourage effect' and has been proposed to regulate synaptic activity of 2-AG. To clarify the activity of these congeners of 2-AG we tested them in neuronal and cell-based signaling assays. The signaling profile for these compounds is inconsistent with an entourage effect. None of the compounds inhibited neurotransmission via CB1 in autaptic neurons. Interestingly, each failed to potentiate 2-AG-mediated depolarization-induced suppression of excitation (DSE), behaving instead as antagonists. Examining other signaling pathways we found that 2-OG interferes with agonist-induced CB1 internalization while 2-PG modestly internalizes CB1 receptors. However in tests of pERK, cAMP and arrestin recruitment, none of the acylglycerols altered CB1 signaling. Our results suggest 1) that these compounds do not serve as entourage compounds under the conditions examined, and 2) that they may instead serve as functional antagonists. Our results suggest that the relationship between 2-AG and its congeners is more nuanced than previously appreciated.
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Affiliation(s)
- Natalia Murataeva
- The Gill Center for Biomolecular Science and the Department of Psychological and Brain Sciences, Indiana University, Bloomington, IN 47405, USA
| | - Amey Dhopeshwarkar
- The Gill Center for Biomolecular Science and the Department of Psychological and Brain Sciences, Indiana University, Bloomington, IN 47405, USA
| | - Danielle Yin
- The Gill Center for Biomolecular Science and the Department of Psychological and Brain Sciences, Indiana University, Bloomington, IN 47405, USA
| | - José Mitjavila
- The Gill Center for Biomolecular Science and the Department of Psychological and Brain Sciences, Indiana University, Bloomington, IN 47405, USA
| | - Heather Bradshaw
- The Gill Center for Biomolecular Science and the Department of Psychological and Brain Sciences, Indiana University, Bloomington, IN 47405, USA
| | - Alex Straiker
- The Gill Center for Biomolecular Science and the Department of Psychological and Brain Sciences, Indiana University, Bloomington, IN 47405, USA.
| | - Ken Mackie
- The Gill Center for Biomolecular Science and the Department of Psychological and Brain Sciences, Indiana University, Bloomington, IN 47405, USA
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Murataeva N, Li S, Oehler O, Miller S, Dhopeshwarkar A, Hu SSJ, Bonanno JA, Bradshaw H, Mackie K, McHugh D, Straiker A. Cannabinoid-induced chemotaxis in bovine corneal epithelial cells. Invest Ophthalmol Vis Sci 2015; 56:3304-13. [PMID: 26024113 DOI: 10.1167/iovs.14-15675] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/24/2022] Open
Abstract
PURPOSE Cannabinoid CB1 receptors are found in abundance in the vertebrate eye, with most tissue types expressing this receptor. However, the function of CB1 receptors in corneal epithelial cells (CECs) is poorly understood. Interestingly, the corneas of CB1 knockout mice heal more slowly after injury via a mechanism proposed to involve protein kinase B (Akt) activation, chemokinesis, and cell proliferation. The current study examined the role of cannabinoids in CEC migration in greater detail. METHODS We determined the role of CB1 receptors in corneal healing. We examined the consequences of their activation on migration and proliferation in bovine CECs (bCECs). We additionally examined the mRNA profile of cannabinoid-related genes and CB1 protein expression as well as CB1 signaling in bovine CECs. RESULTS We now report that activation of CB1 with physiologically relevant concentrations of the synthetic agonist WIN55212-2 (WIN) induces bCEC migration via chemotaxis, an effect fully blocked by the CB1 receptor antagonist SR141716. The endogenous agonist 2-arachidonoylglycerol (2-AG) also enhances migration. Separately, mRNA for most cannabinoid-related proteins are present in bovine corneal epithelium and cultured bCECs. Notably absent are CB2 receptors and the 2-AG synthesizing enzyme diglycerol lipase-α (DAGLα). The signaling profile of CB1 activation is complex, with inactivation of mitogen-activated protein kinase (MAPK). Lastly, CB1 activation does not induce bCEC proliferation, but may instead antagonize EGF-induced proliferation. CONCLUSIONS In summary, we find that CB1-based signaling machinery is present in bovine cornea and that activation of this system induces chemotaxis.
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Affiliation(s)
- Natalia Murataeva
- The Gill Center for Biomolecular Science and the Department of Psychological and Brain Sciences Indiana University, Bloomington, Indiana, United States
| | - Shimin Li
- School of Optometry, Indiana University, Bloomington, Indiana, United States
| | - Olivia Oehler
- The Gill Center for Biomolecular Science and the Department of Psychological and Brain Sciences Indiana University, Bloomington, Indiana, United States
| | - Sally Miller
- The Gill Center for Biomolecular Science and the Department of Psychological and Brain Sciences Indiana University, Bloomington, Indiana, United States
| | - Amey Dhopeshwarkar
- The Gill Center for Biomolecular Science and the Department of Psychological and Brain Sciences Indiana University, Bloomington, Indiana, United States
| | - Sherry Shu-Jung Hu
- Department of Psychology, National Cheng Kung University, Tainan, Taiwan
| | - Joseph A Bonanno
- School of Optometry, Indiana University, Bloomington, Indiana, United States
| | - Heather Bradshaw
- The Gill Center for Biomolecular Science and the Department of Psychological and Brain Sciences Indiana University, Bloomington, Indiana, United States
| | - Ken Mackie
- The Gill Center for Biomolecular Science and the Department of Psychological and Brain Sciences Indiana University, Bloomington, Indiana, United States
| | - Douglas McHugh
- Frank H. Netter MD School of Medicine, Quinnipiac University, North Haven, Connecticut, United States
| | - Alex Straiker
- The Gill Center for Biomolecular Science and the Department of Psychological and Brain Sciences Indiana University, Bloomington, Indiana, United States
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Murataeva N, Straiker A, Mackie K. Parsing the players: 2-arachidonoylglycerol synthesis and degradation in the CNS. Br J Pharmacol 2014; 171:1379-91. [PMID: 24102242 PMCID: PMC3954479 DOI: 10.1111/bph.12411] [Citation(s) in RCA: 160] [Impact Index Per Article: 16.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/13/2013] [Revised: 08/29/2013] [Accepted: 09/08/2013] [Indexed: 12/17/2022] Open
Abstract
UNLABELLED The endogenous cannabinoid signalling system, composed of endogenous cannabinoids, cannabinoid receptors and the enzymes that synthesize and degrade the endogenous cannabinoids, is much more complex than initially conceptualized. 2-Arachidonoylglycerol (2-AG) is the most abundant endocannabinoid and plays a major role in CNS development and synaptic plasticity. Over the past decade, many key players in 2-AG synthesis and degradation have been identified and characterized. Most 2-AG is synthesized from membrane phospholipids via sequential activation of a phospholipase Cβ and a diacylglycerol lipase, although other pathways may contribute in specialized settings. 2-AG breakdown is more complicated with at least eight different enzymes participating. These enzymes can either degrade 2-AG into its components, arachidonic acid and glycerol, or transform 2-AG into highly bioactive signal molecules. The implications of the precise temporal and spatial control of the expression and function of these pleiotropic metabolizing enzymes have only recently come to be appreciated. In this review, we will focus on the primary organization of the synthetic and degradative pathways of 2-AG and then discuss more recent findings and their implications, with an eye towards the biological and therapeutic implications of manipulating 2-AG synthesis and metabolism. LINKED ARTICLES This article is part of a themed section on Cannabinoids 2013. To view the other articles in this section visit http://dx.doi.org/10.1111/bph.2014.171.issue-6.
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Affiliation(s)
- N Murataeva
- Department of Psychological and Brain Sciences, Gill Center for Biomolecular Science, Indiana UniversityBloomington, IN, USA
| | - A Straiker
- Department of Psychological and Brain Sciences, Gill Center for Biomolecular Science, Indiana UniversityBloomington, IN, USA
| | - K Mackie
- Department of Psychological and Brain Sciences, Gill Center for Biomolecular Science, Indiana UniversityBloomington, IN, USA
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