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Cabral GA, Rogers TJ, Lichtman AH. Turning Over a New Leaf: Cannabinoid and Endocannabinoid Modulation of Immune Function. J Neuroimmune Pharmacol 2015; 10:193-203. [PMID: 26054900 PMCID: PMC4469415 DOI: 10.1007/s11481-015-9615-z] [Citation(s) in RCA: 65] [Impact Index Per Article: 7.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/07/2015] [Accepted: 05/04/2015] [Indexed: 02/06/2023]
Abstract
Cannabis is a complex substance that harbors terpenoid-like compounds referred to as phytocannabinoids. The major psychoactive phytocannabinoid found in cannabis ∆(9)-tetrahydrocannabinol (THC) produces the majority of its pharmacological effects through two cannabinoid receptors, termed CB1 and CB2. The discovery of these receptors as linked functionally to distinct biological effects of THC, and the subsequent development of synthetic cannabinoids, precipitated discovery of the endogenous cannabinoid (or endocannabinoid) system. This system consists of the endogenous lipid ligands N- arachidonoylethanolamine (anandamide; AEA) and 2-arachidonylglycerol (2-AG), their biosynthetic and degradative enzymes, and the CB1 and CB2 receptors that they activate. Endocannabinoids have been identified in immune cells such as monocytes, macrophages, basophils, lymphocytes, and dendritic cells and are believed to be enzymatically produced and released "on demand" in a similar fashion as the eicosanoids. It is now recognized that other phytocannabinoids such as cannabidiol (CBD) and cannabinol (CBN) can alter the functional activities of the immune system. This special edition of the Journal of Neuroimmune Pharmacology (JNIP) presents a collection of cutting edge original research and review articles on the medical implications of phytocannabinoids and the endocannabinoid system. The goal of this special edition is to provide an unbiased assessment of the state of research related to this topic from leading researchers in the field. The potential untoward effects as well as beneficial uses of marijuana, its phytocannabinoid composition, and synthesized cannabinoid analogs are discussed. In addition, the role of the endocannabinoid system and approaches to its manipulation to treat select human disease processes are addressed.
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Affiliation(s)
- Guy A Cabral
- Department of Microbiology and Immunology, Virginia Commonwealth University, Richmond, VA, 23298, USA,
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52
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Hjorth S, Karlsson C, Jucaite A, Varnäs K, Wählby Hamrén U, Johnström P, Gulyás B, Donohue SR, Pike VW, Halldin C, Farde L. A PET study comparing receptor occupancy by five selective cannabinoid 1 receptor antagonists in non-human primates. Neuropharmacology 2015; 101:519-30. [PMID: 25791528 DOI: 10.1016/j.neuropharm.2015.03.002] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/20/2014] [Revised: 02/05/2015] [Accepted: 03/07/2015] [Indexed: 01/14/2023]
Abstract
There is a medical need for safe and efficacious anti-obesity drugs with acceptable side effect profiles. To mitigate the challenge posed by translating target interaction across species and balancing beneficial vs. adverse effects, a positron emission tomography (PET) approach could help guide clinical dose optimization. Thus, as part of a compound differentiation effort, three novel selective CB1 receptor (CB1R) antagonists, developed by AstraZeneca (AZ) for the treatment of obesity, were compared with two clinically tested reference compounds, rimonabant and taranabant, with regard to receptor occupancy relative to dose and exposure. A total of 42 PET measurements were performed in 6 non-human primates using the novel CB1R antagonist radioligand [(11)C]SD5024. The AZ CB1R antagonists bound in a saturable manner to brain CB1R with in vivo affinities similar to that of rimonabant and taranabant, compounds with proven weight loss efficacy in clinical trials. Interestingly, it was found that exposures corresponding to those needed for optimal clinical efficacy of rimonabant and taranabant resulted in a CB1R occupancy typically around ∼20-30%, thus much lower than what would be expected for classical G-protein coupled receptor (GPCR) antagonists in other therapeutic contexts. These findings are also discussed in relation to emerging literature on the potential usefulness of 'neutral' vs. 'classical' CB1R (inverse agonist) antagonists. The study additionally highlighted the usefulness of the radioligand [(11)C]SD5024 as a specific tracer for CB1R in the primate brain, though an arterial input function would ideally be required in future studies to further assure accurate quantitative analysis of specific binding.
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Affiliation(s)
- Stephan Hjorth
- Biosciences, CVMD Innovative Medicines, AstraZeneca R&D, Mölndal, Sweden
| | - Cecilia Karlsson
- CVMD Translational Medicine Unit, Early Clinical Development, Innovative Medicines, AstraZeneca R&D, Mölndal, Sweden.
| | - Aurelija Jucaite
- AstraZeneca Translational Science Centre and Department of Clinical Neuroscience, Karolinska Institutet, Stockholm, Sweden
| | - Katarina Varnäs
- Centre for Psychiatric Research, Department of Clinical Neuroscience, Karolinska Institutet, Stockholm, Sweden
| | - Ulrika Wählby Hamrén
- Quantitative Clinical Pharmacology, Early Clinical Development, Innovative Medicines, AstraZeneca R&D, Mölndal, Sweden
| | - Peter Johnström
- AstraZeneca Translational Science Centre and Department of Clinical Neuroscience, Karolinska Institutet, Stockholm, Sweden
| | - Balázs Gulyás
- Centre for Psychiatric Research, Department of Clinical Neuroscience, Karolinska Institutet, Stockholm, Sweden
| | - Sean R Donohue
- Molecular Imaging Branch, National Institute of Mental Health, National Institutes of Health, Bethesda, MD 20892, USA
| | - Victor W Pike
- Molecular Imaging Branch, National Institute of Mental Health, National Institutes of Health, Bethesda, MD 20892, USA
| | - Christer Halldin
- Centre for Psychiatric Research, Department of Clinical Neuroscience, Karolinska Institutet, Stockholm, Sweden
| | - Lars Farde
- AstraZeneca Translational Science Centre and Department of Clinical Neuroscience, Karolinska Institutet, Stockholm, Sweden
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Elmes MW, Kaczocha M, Berger WT, Leung K, Ralph BP, Wang L, Sweeney JM, Miyauchi JT, Tsirka SE, Ojima I, Deutsch DG. Fatty acid-binding proteins (FABPs) are intracellular carriers for Δ9-tetrahydrocannabinol (THC) and cannabidiol (CBD). J Biol Chem 2015; 290:8711-21. [PMID: 25666611 DOI: 10.1074/jbc.m114.618447] [Citation(s) in RCA: 215] [Impact Index Per Article: 23.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/15/2014] [Indexed: 01/03/2023] Open
Abstract
Δ(9)-Tetrahydrocannabinol (THC) and cannabidiol (CBD) occur naturally in marijuana (Cannabis) and may be formulated, individually or in combination in pharmaceuticals such as Marinol or Sativex. Although it is known that these hydrophobic compounds can be transported in blood by albumin or lipoproteins, the intracellular carrier has not been identified. Recent reports suggest that CBD and THC elevate the levels of the endocannabinoid anandamide (AEA) when administered to humans, suggesting that phytocannabinoids target cellular proteins involved in endocannabinoid clearance. Fatty acid-binding proteins (FABPs) are intracellular proteins that mediate AEA transport to its catabolic enzyme fatty acid amide hydrolase (FAAH). By computational analysis and ligand displacement assays, we show that at least three human FABPs bind THC and CBD and demonstrate that THC and CBD inhibit the cellular uptake and catabolism of AEA by targeting FABPs. Furthermore, we show that in contrast to rodent FAAH, CBD does not inhibit the enzymatic actions of human FAAH, and thus FAAH inhibition cannot account for the observed increase in circulating AEA in humans following CBD consumption. Using computational molecular docking and site-directed mutagenesis we identify key residues within the active site of FAAH that confer the species-specific sensitivity to inhibition by CBD. Competition for FABPs may in part or wholly explain the increased circulating levels of endocannabinoids reported after consumption of cannabinoids. These data shed light on the mechanism of action of CBD in modulating the endocannabinoid tone in vivo and may explain, in part, its reported efficacy toward epilepsy and other neurological disorders.
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Affiliation(s)
| | - Martin Kaczocha
- From the Departments of Biochemistry and Cell Biology, Anesthesiology, and
| | - William T Berger
- Chemistry, the Institute of Chemical Biology and Drug Discovery, and
| | - KwanNok Leung
- From the Departments of Biochemistry and Cell Biology
| | - Brian P Ralph
- From the Departments of Biochemistry and Cell Biology
| | - Liqun Wang
- From the Departments of Biochemistry and Cell Biology
| | | | - Jeremy T Miyauchi
- the Department of Pharmacological Sciences, Stony Brook University, Stony Brook, New York 11795-5215
| | - Stella E Tsirka
- the Department of Pharmacological Sciences, Stony Brook University, Stony Brook, New York 11795-5215
| | - Iwao Ojima
- Chemistry, the Institute of Chemical Biology and Drug Discovery, and
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Pacioni G, Rapino C, Zarivi O, Falconi A, Leonardi M, Battista N, Colafarina S, Sergi M, Bonfigli A, Miranda M, Barsacchi D, Maccarrone M. Truffles contain endocannabinoid metabolic enzymes and anandamide. PHYTOCHEMISTRY 2015; 110:104-110. [PMID: 25433633 DOI: 10.1016/j.phytochem.2014.11.012] [Citation(s) in RCA: 20] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/04/2014] [Revised: 10/16/2014] [Accepted: 11/05/2014] [Indexed: 06/04/2023]
Abstract
Truffles are the fruiting body of fungi, members of the Ascomycota phylum endowed with major gastronomic and commercial value. The development and maturation of their reproductive structure are dependent on melanin synthesis. Since anandamide, a prominent member of the endocannabinoid system (ECS), is responsible for melanin synthesis in normal human epidermal melanocytes, we thought that ECS might be present also in truffles. Here, we show the expression, at the transcriptional and translational levels, of most ECS components in the black truffle Tuber melanosporum Vittad. at maturation stage VI. Indeed, by means of molecular biology and immunochemical techniques, we found that truffles contain the major metabolic enzymes of the ECS, while they do not express the most relevant endocannabinoid-binding receptors. In addition, we measured anandamide content in truffles, at different maturation stages (from III to VI), through liquid chromatography-mass spectrometric analysis, whereas the other relevant endocannabinoid 2-arachidonoylglycerol was below the detection limit. Overall, our unprecedented results suggest that anandamide and ECS metabolic enzymes have evolved earlier than endocannabinoid-binding receptors, and that anandamide might be an ancient attractant to truffle eaters, that are well-equipped with endocannabinoid-binding receptors.
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Affiliation(s)
- Giovanni Pacioni
- Department of Life, Health and Environmental Sciences, University of L'Aquila, L'Aquila, Italy
| | - Cinzia Rapino
- Faculty of Veterinary Medicine, University of Teramo, Teramo, Italy; StemTeCh Group, Chieti, Italy.
| | - Osvaldo Zarivi
- Department of Life, Health and Environmental Sciences, University of L'Aquila, L'Aquila, Italy
| | | | - Marco Leonardi
- Department of Life, Health and Environmental Sciences, University of L'Aquila, L'Aquila, Italy
| | - Natalia Battista
- Faculty of Bioscience and Technology for Food, Agriculture and Environment, University of Teramo, Teramo, Italy; European Center for Brain Research/IRCCS Santa Lucia Foundation, Rome, Italy
| | - Sabrina Colafarina
- Department of Life, Health and Environmental Sciences, University of L'Aquila, L'Aquila, Italy
| | - Manuel Sergi
- Faculty of Bioscience and Technology for Food, Agriculture and Environment, University of Teramo, Teramo, Italy
| | - Antonella Bonfigli
- Department of Life, Health and Environmental Sciences, University of L'Aquila, L'Aquila, Italy
| | - Michele Miranda
- Department of Life, Health and Environmental Sciences, University of L'Aquila, L'Aquila, Italy
| | - Daniela Barsacchi
- Faculty of Bioscience and Technology for Food, Agriculture and Environment, University of Teramo, Teramo, Italy
| | - Mauro Maccarrone
- European Center for Brain Research/IRCCS Santa Lucia Foundation, Rome, Italy; Center of Integrated Research, Campus Bio-Medico University of Rome, Rome, Italy.
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Abstract
The cannabinoid receptors are G protein-coupled receptors activated by endocannabinoids or exogenous agonist such as tetrahydrocannabinol. Upon agonist binding, cannabinoid receptors will activate G proteins of the Gi family, which in turn inhibits adenylyl cyclase. Recently, inverse agonists and neutral antagonist for cannabinoid receptors have been discovered, demonstrating constitutive activity of the cannabinoid receptors. This chapter will discuss the current state of the art and provide a framework for evaluating constitutive receptor activity and distinguishing constitutive receptor activity from constitutive endogenous agonist tone.
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56
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Ladarre D, Roland AB, Biedzinski S, Ricobaraza A, Lenkei Z. Polarized cellular patterns of endocannabinoid production and detection shape cannabinoid signaling in neurons. Front Cell Neurosci 2015; 8:426. [PMID: 25610369 PMCID: PMC4285097 DOI: 10.3389/fncel.2014.00426] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/13/2014] [Accepted: 11/26/2014] [Indexed: 11/13/2022] Open
Abstract
Neurons display important differences in plasma membrane composition between somatodendritic and axonal compartments, potentially leading to currently unexplored consequences in G-protein-coupled-receptor signaling. Here, by using highly-resolved biosensor imaging to measure local changes in basal levels of key signaling components, we explored features of type-1 cannabinoid receptor (CB1R) signaling in individual axons and dendrites of cultured rat hippocampal neurons. Activation of endogenous CB1Rs led to rapid, Gi/o-protein- and cAMP-mediated decrease of cyclic-AMP-dependent protein kinase (PKA) activity in the somatodendritic compartment. In axons, PKA inhibition was significantly stronger, in line with axonally-polarized distribution of CB1Rs. Conversely, inverse agonist AM281 produced marked rapid increase of basal PKA activation in somata and dendrites, but not in axons, removing constitutive activation of CB1Rs generated by local production of the endocannabinoid 2-arachidonoylglycerol (2-AG). Interestingly, somatodendritic 2-AG levels differently modified signaling responses to CB1R activation by Δ(9)-THC, the psychoactive compound of marijuana, and by the synthetic cannabinoids WIN55,212-2 and CP55,940. These highly contrasted differences in sub-neuronal signaling responses warrant caution in extrapolating pharmacological profiles, which are typically obtained in non-polarized cells, to predict in vivo responses of axonal (i.e., presynaptic) GPCRs. Therefore, our results suggest that enhanced comprehension of GPCR signaling constraints imposed by neuronal cell biology may improve the understanding of neuropharmacological action.
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Affiliation(s)
- Delphine Ladarre
- Brain Plasticity Unit, ESPCI-ParisTech Paris, France ; Centre National de la Recherche Scientifique UMR 8249 Paris, France
| | - Alexandre B Roland
- Brain Plasticity Unit, ESPCI-ParisTech Paris, France ; Centre National de la Recherche Scientifique UMR 8249 Paris, France
| | - Stefan Biedzinski
- Brain Plasticity Unit, ESPCI-ParisTech Paris, France ; Centre National de la Recherche Scientifique UMR 8249 Paris, France
| | - Ana Ricobaraza
- Brain Plasticity Unit, ESPCI-ParisTech Paris, France ; Centre National de la Recherche Scientifique UMR 8249 Paris, France
| | - Zsolt Lenkei
- Brain Plasticity Unit, ESPCI-ParisTech Paris, France ; Centre National de la Recherche Scientifique UMR 8249 Paris, France
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57
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Khasabova IA, Yao X, Paz J, Lewandowski CT, Lindberg AE, Coicou L, Burlakova N, Simone DA, Seybold VS. JZL184 is anti-hyperalgesic in a murine model of cisplatin-induced peripheral neuropathy. Pharmacol Res 2014; 90:67-75. [PMID: 25304184 DOI: 10.1016/j.phrs.2014.09.008] [Citation(s) in RCA: 35] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 08/15/2014] [Revised: 09/29/2014] [Accepted: 09/30/2014] [Indexed: 12/28/2022]
Abstract
Cisplatin has been used effectively to treat a variety of cancers but its use is limited by the development of painful peripheral neuropathy. Because the endocannabinoid 2-arachidonoyl-sn-glycerol (2-AG) is anti-hyperalgesic in several preclinical models of chronic pain, the anti-hyperalgesic effect of JZL184, an inhibitor of 2-AG hydrolysis, was tested in a murine model of cisplatin-induced hyperalgesia. Systemic injection of cisplatin (1mg/kg) produced mechanical hyperalgesia when administered daily for 7 days. Daily peripheral administration of a low dose of JZL184 in conjunction with cisplatin blocked the expression of mechanical hyperalgesia. Acute injection of a cannabinoid (CB)-1 but not a CB2 receptor antagonist reversed the anti-hyperalgesic effect of JZL184 indicating that downstream activation of CB1 receptors suppressed the expression of mechanical hyperalgesia. Components of endocannabinoid signaling in plantar hind paw skin and lumbar dorsal root ganglia (DRGs) were altered by treatments with cisplatin and JZL184. Treatment with cisplatin alone reduced levels of 2-AG and AEA in skin and DRGs as well as CB2 receptor protein in skin. Combining treatment of JZL184 with cisplatin increased 2-AG in DRGs compared to cisplatin alone but had no effect on the amount of 2-AG in skin. Evidence that JZL184 decreased the uptake of [(3)H]AEA into primary cultures of DRGs at a concentration that also inhibited the enzyme fatty acid amide hydrolase, in conjunction with data that 2-AG mimicked the effect of JZL184 on [(3)H]AEA uptake support the conclusion that AEA most likely mediates the anti-hyperalgesic effect of JZL184 in this model.
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MESH Headings
- Amides
- Analgesics/pharmacology
- Analgesics/therapeutic use
- Animals
- Antineoplastic Agents
- Arachidonic Acids/metabolism
- Arachidonic Acids/pharmacology
- Benzodioxoles/pharmacology
- Benzodioxoles/therapeutic use
- Cells, Cultured
- Cisplatin
- Disease Models, Animal
- Endocannabinoids/metabolism
- Endocannabinoids/pharmacology
- Ethanolamines/metabolism
- Ganglia, Spinal/cytology
- Ganglia, Spinal/drug effects
- Ganglia, Spinal/metabolism
- Glycerides/metabolism
- Glycerides/pharmacology
- Hyperalgesia/drug therapy
- Hyperalgesia/metabolism
- Indoles/pharmacology
- Male
- Mesencephalon/drug effects
- Mesencephalon/metabolism
- Mice
- Mice, Inbred C3H
- Monoacylglycerol Lipases/antagonists & inhibitors
- Morpholines/pharmacology
- Neuralgia/chemically induced
- Neuralgia/drug therapy
- Neuralgia/metabolism
- Palmitic Acids/metabolism
- Piperidines/pharmacology
- Piperidines/therapeutic use
- Polyunsaturated Alkamides/metabolism
- Pyrazoles/pharmacology
- Receptor, Cannabinoid, CB1/antagonists & inhibitors
- Receptor, Cannabinoid, CB1/metabolism
- Receptor, Cannabinoid, CB2/antagonists & inhibitors
- Receptor, Cannabinoid, CB2/metabolism
- Skin/drug effects
- Skin/metabolism
- Spinal Cord/drug effects
- Spinal Cord/metabolism
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Affiliation(s)
- Iryna A Khasabova
- Department of Diagnostic and Biological Sciences, Dental School, University of Minnesota, USA
| | - Xu Yao
- Department of Diagnostic and Biological Sciences, Dental School, University of Minnesota, USA
| | - Justin Paz
- Department of Diagnostic and Biological Sciences, Dental School, University of Minnesota, USA
| | | | - Amy E Lindberg
- Pharmacology Graduate Program, University of Minnesota, USA
| | - Lia Coicou
- Department of Neuroscience, Medical School, University of Minnesota, USA
| | - Natasha Burlakova
- Department of Diagnostic and Biological Sciences, Dental School, University of Minnesota, USA
| | - Don A Simone
- Department of Diagnostic and Biological Sciences, Dental School, University of Minnesota, USA
| | - Virginia S Seybold
- Department of Neuroscience, Medical School, University of Minnesota, USA.
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58
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Fišar Z, Singh N, Hroudová J. Cannabinoid-induced changes in respiration of brain mitochondria. Toxicol Lett 2014; 231:62-71. [PMID: 25195527 DOI: 10.1016/j.toxlet.2014.09.002] [Citation(s) in RCA: 80] [Impact Index Per Article: 8.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/18/2014] [Revised: 08/31/2014] [Accepted: 09/03/2014] [Indexed: 02/06/2023]
Abstract
Cannabinoids exert various biological effects that are either receptor-mediated or independent of receptor signaling. Mitochondrial effects of cannabinoids were interpreted either as non-receptor-mediated alteration of mitochondrial membranes, or as indirect consequences of activation of plasma membrane type 1 cannabinoid receptors (CB1). Recently, CB1 receptors were confirmed to be localized to the membranes of neuronal mitochondria, where their activation directly regulates respiration and energy production. Here, we performed in-depth analysis of cannabinoid-induced changes of mitochondrial respiration using both an antagonist/inverse agonist of CB1 receptors, AM251 and the cannabinoid receptor agonists, Δ(9)-tetrahydrocannabinol (THC), cannabidiol, anandamide, and WIN 55,212-2. Relationships were determined between cannabinoid concentration and respiratory rate driven by substrates of complex I, II or IV in pig brain mitochondria. Either full or partial inhibition of respiratory rate was found for the tested drugs, with an IC50 in the micromolar range, which verified the significant role of non-receptor-mediated mechanism in inhibiting mitochondrial respiration. Effect of stepwise application of THC and AM251 evidenced protective role of AM251 and corroborated the participation of CB1 receptor activation in the inhibition of mitochondrial respiration. We proposed a model, which includes both receptor- and non-receptor-mediated mechanisms of cannabinoid action on mitochondrial respiration. This model explains both the inhibitory effect of cannabinoids and the protective effect of the CB1 receptor inverse agonist.
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Affiliation(s)
- Zdeněk Fišar
- Department of Psychiatry, First Faculty of Medicine, Charles University in Prague and General University Hospital in Prague, Ke Karlovu 11, Prague 2 120 00, Czech Republic.
| | - Namrata Singh
- Department of Psychiatry, First Faculty of Medicine, Charles University in Prague and General University Hospital in Prague, Ke Karlovu 11, Prague 2 120 00, Czech Republic.
| | - Jana Hroudová
- Department of Psychiatry, First Faculty of Medicine, Charles University in Prague and General University Hospital in Prague, Ke Karlovu 11, Prague 2 120 00, Czech Republic.
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59
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Hutson PH, Tarazi FI, Madhoo M, Slawecki C, Patkar AA. Preclinical pharmacology of amphetamine: Implications for the treatment of neuropsychiatric disorders. Pharmacol Ther 2014; 143:253-64. [DOI: 10.1016/j.pharmthera.2014.03.005] [Citation(s) in RCA: 21] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/18/2013] [Accepted: 03/14/2014] [Indexed: 11/28/2022]
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60
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den Boon FS, Werkman TR, Schaafsma-Zhao Q, Houthuijs K, Vitalis T, Kruse CG, Wadman WJ, Chameau P. Activation of type-1 cannabinoid receptor shifts the balance between excitation and inhibition towards excitation in layer II/III pyramidal neurons of the rat prelimbic cortex. Pflugers Arch 2014; 467:1551-1564. [PMID: 25081244 DOI: 10.1007/s00424-014-1586-z] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/03/2014] [Revised: 07/17/2014] [Accepted: 07/21/2014] [Indexed: 12/17/2022]
Abstract
Activation of the endocannabinoid (eCB) system by exogenous cannabinoids (drug abuse) can alter the physiology of the brain circuits involved in higher-order cognitive functions such as the medial prefrontal cortex (mPFC). A proper balance between excitation and inhibition (E/I balance) is critical for neuronal network oscillations underlying cognitive functions. Since type-1 cannabinoid receptors (CB1Rs), expressed in many brain areas including the mPFC, can modulate excitatory and inhibitory neurotransmission, we aimed to determine whether CB1R activation results in modifications of the E/I balance. We first confirm the presence of functional presynaptic CB1Rs that can modulate both excitatory and inhibitory inputs to layer II/III pyramidal neurons of the prelimbic (PL) area of the mPFC. By decomposing the synaptic response evoked by layer I stimulation into its excitatory and inhibitory components, we show that in vitro CB1R activation with the cannabinoid receptor agonists WIN55,212-2 (WIN) and CP-55940 (CP) modulates the balance between excitation and inhibition (E/I balance) of layer II/III pyramidal neurons. This treatment caused a significant shift of the E/I balance towards excitation, from 18/82 % to 25/75 % (WIN) and from 17/83 to 30/70 % (CP). Finally, when animals were injected with a cannabinoid receptor agonist, we observed a shift of the E/I balance (measured in vitro) towards excitation 1 h after WIN (24/76 %) or after CP injection (30/70 %) when compared to vehicle-injected animals (18/82 %). This modulation of the E/I balance by CB1Rs may thus be fundamental in the regulation of local PL cortical network excitability and could be the mechanism through which excessive CB1R activation (cannabis abuse) affects cognitive functions.
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Affiliation(s)
- Femke S den Boon
- Center for Neuroscience, Swammerdam Institute for Life Sciences, University of Amsterdam, Science Park 904, 1098 XH, Amsterdam, Netherlands
| | - Taco R Werkman
- Center for Neuroscience, Swammerdam Institute for Life Sciences, University of Amsterdam, Science Park 904, 1098 XH, Amsterdam, Netherlands.
| | - Qiluan Schaafsma-Zhao
- Center for Neuroscience, Swammerdam Institute for Life Sciences, University of Amsterdam, Science Park 904, 1098 XH, Amsterdam, Netherlands
| | - Kas Houthuijs
- Center for Neuroscience, Swammerdam Institute for Life Sciences, University of Amsterdam, Science Park 904, 1098 XH, Amsterdam, Netherlands
| | - Tania Vitalis
- CNRS-UMR 7637, Brain Plasticity Unit, ESPCI ParisTech, 10 rue Vauquelin, 75005, Paris, France
| | - Chris G Kruse
- Center for Neuroscience, Swammerdam Institute for Life Sciences, University of Amsterdam, Science Park 904, 1098 XH, Amsterdam, Netherlands
| | - Wytse J Wadman
- Center for Neuroscience, Swammerdam Institute for Life Sciences, University of Amsterdam, Science Park 904, 1098 XH, Amsterdam, Netherlands
| | - Pascal Chameau
- Center for Neuroscience, Swammerdam Institute for Life Sciences, University of Amsterdam, Science Park 904, 1098 XH, Amsterdam, Netherlands
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61
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Pava MJ, Woodward JJ. Chronic ethanol alters network activity and endocannabinoid signaling in the prefrontal cortex. Front Integr Neurosci 2014; 8:58. [PMID: 25100953 PMCID: PMC4103173 DOI: 10.3389/fnint.2014.00058] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/29/2014] [Accepted: 06/27/2014] [Indexed: 11/22/2022] Open
Abstract
Chronic use of alcohol is associated with structural and functional alterations in brain areas that subserve cognitive processes. Of particular importance is the prefrontal cortex (PFC) that is involved in higher order behaviors such as decision making, risk assessment and judgment. Understanding the mechanisms that underlie alcohol's effects on PFC function is important for developing strategies to overcome the cognitive deficits that may predispose individuals to relapse. Our previous studies showed that acutely applied ethanol inhibits network activity in slices of prefrontal cortex and that exogenous and endogenous cannabinoids modulate up-state dynamics. In the present study, we examined the effects of repeated alcohol exposure on cannabinoid regulation of up-states in slice cultures of the prefrontal cortex. Compared to controls, up-state duration, but not amplitude was enhanced when measured 4 days after a 10 day ethanol exposure (44 mM ethanol; equivalent to 0.2% blood ethanol). Administration of the CB1 agonist WIN 55,212-2 enhanced the amplitude of up-states in control cultures but not in those treated previously with ethanol. This lack of effect occurred in the absence of any noticeable change in CB1 receptor protein expression. Chronic ethanol treatment and withdrawal also blunted WIN's inhibition of electrically evoked GABA IPSCs in layer II/III pyramidal neurons but not those in layer V/VI. WIN inhibited the amplitude of spontaneous GABA IPSCs in both layers and the magnitude of this effect was not altered by ethanol treatment. However, in layer V/VI neurons, WIN's effect on sIPSC frequency was greater in ethanol treated cultures. WIN also inhibited electrically evoked NMDA EPSCs in both layer II/III and V/VI neurons but this action was unaffected by ethanol treatment and withdrawal. Overall, these results suggest that ethanol's down-regulation of cannabinoid signaling results in altered network activity in the prefrontal cortex.
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Affiliation(s)
- Matthew J Pava
- Department of Neuroscience, Medical University of South Carolina Charleston, SC, USA
| | - John J Woodward
- Department of Neuroscience, Medical University of South Carolina Charleston, SC, USA
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Endocannabinoid 2-arachidonylglycerol protects primary cultured neurons against homocysteine-induced impairments in rat caudate nucleus through CB1 receptor. J Mol Neurosci 2014; 55:500-8. [PMID: 25007951 DOI: 10.1007/s12031-014-0371-y] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/29/2014] [Accepted: 07/01/2014] [Indexed: 01/29/2023]
Abstract
Homocysteine (Hcy) is a high risk factor for Alzheimer's disease (AD). Caudate nucleus (CN), the major component of basal ganglia in the brain, is also involved in many neurological disorders. 2-Arachidonoylglycerol (2-AG), the true natural ligand for cannabinoid type-1 (CB1) receptors and the most abundant endogenous cannabinoid, has been shown to exhibit neuroprotective effects through its anti-inflammatory action from proinflammatory stimuli in the hippocampus and CN. However, it is still not well understood whether that 2-AG is also able to protect CN neurons from Hcy harmful insults. In the present work, we explored that 2-AG significantly protects CN neurons in culture against Hcy-induced response. 2-AG is capable of inhibiting elevation of Hcy-induced cyclooxygenase-2 expression associated with nuclear factor-kappaB/p38MAPK/ERK1/2 signaling pathway through CB1 receptors-dependent way in primary cultured CN neurons. Our study reveals the therapeutic potential for 2-AG for the treatment of neurodegenerative diseases, such as AD.
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Sanson B, Wang T, Sun J, Wang L, Kaczocha M, Ojima I, Deutsch D, Li H. Crystallographic study of FABP5 as an intracellular endocannabinoid transporter. ACTA CRYSTALLOGRAPHICA. SECTION D, BIOLOGICAL CRYSTALLOGRAPHY 2014; 70:290-8. [PMID: 24531463 PMCID: PMC3940194 DOI: 10.1107/s1399004713026795] [Citation(s) in RCA: 38] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/10/2013] [Accepted: 09/30/2013] [Indexed: 11/10/2022]
Abstract
In addition to binding intracellular fatty acids, fatty-acid-binding proteins (FABPs) have recently been reported to also transport the endocannabinoids anandamide (AEA) and 2-arachidonoylglycerol (2-AG), arachidonic acid derivatives that function as neurotransmitters and mediate a diverse set of physiological and psychological processes. To understand how the endocannabinoids bind to FABPs, the crystal structures of FABP5 in complex with AEA, 2-AG and the inhibitor BMS-309403 were determined. These ligands are shown to interact primarily with the substrate-binding pocket via hydrophobic interactions as well as a common hydrogen bond to the Tyr131 residue. This work advances our understanding of FABP5-endocannabinoid interactions and may be useful for future efforts in the development of small-molecule inhibitors to raise endocannabinoid levels.
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Affiliation(s)
- Benoît Sanson
- Biosciences Department, Brookhaven National Laboratory, Upton, NY 11973-5000, USA
| | - Tao Wang
- Biosciences Department, Brookhaven National Laboratory, Upton, NY 11973-5000, USA
| | - Jing Sun
- Department of Biochemistry and Cell Biology, Stony Brook University, Stony Brook, NY 11794-5213, USA
| | - Liqun Wang
- Department of Biochemistry and Cell Biology, Stony Brook University, Stony Brook, NY 11794-5213, USA
| | - Martin Kaczocha
- Department of Biochemistry and Cell Biology, Stony Brook University, Stony Brook, NY 11794-5213, USA
| | - Iwao Ojima
- Department of Chemistry, Stony Brook University, Stony Brook, NY 1794-3400, USA
- Institute of Chemical Biology and Drug Discovery, Stony Brook University, Stony Brook, NY 11794-3400, USA
| | - Dale Deutsch
- Department of Biochemistry and Cell Biology, Stony Brook University, Stony Brook, NY 11794-5213, USA
- Institute of Chemical Biology and Drug Discovery, Stony Brook University, Stony Brook, NY 11794-3400, USA
| | - Huilin Li
- Biosciences Department, Brookhaven National Laboratory, Upton, NY 11973-5000, USA
- Department of Biochemistry and Cell Biology, Stony Brook University, Stony Brook, NY 11794-5213, USA
- Institute of Chemical Biology and Drug Discovery, Stony Brook University, Stony Brook, NY 11794-3400, USA
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64
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van Winkel R, Kuepper R. Epidemiological, neurobiological, and genetic clues to the mechanisms linking cannabis use to risk for nonaffective psychosis. Annu Rev Clin Psychol 2014; 10:767-91. [PMID: 24471373 DOI: 10.1146/annurev-clinpsy-032813-153631] [Citation(s) in RCA: 41] [Impact Index Per Article: 4.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
Abstract
Epidemiological studies have shown that the association between cannabis and psychosis is robust and consistent across different samples, with compelling evidence for a dose-response relationship. Because longitudinal work indicates that cannabis use precedes psychotic symptoms, it seems reasonable to assume a causal relationship. However, more work is needed to address the possibility of gene-environment correlation (for example, genetic risk for psychosis causing onset of cannabis use). Moreover, knowledge about underlying biological mechanisms linking cannabis use and psychosis is still relatively limited. In order to understand how cannabis use may lead to an increased risk for psychosis, in the present article we (a) review the epidemiological, neurobiological, and genetic evidence linking cannabinoids and psychosis, (b) assess the quality of the evidence, and finally (c) try to integrate the most robust findings into a neurodevelopmental model of cannabis-induced psychosis and identify the gaps in knowledge that are in need of further investigation.
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Affiliation(s)
- Ruud van Winkel
- Department of Psychiatry and Psychology, School of Mental Health and Neuroscience, European Graduate School of Neuroscience (EURON), South Limburg Mental Health Research and Teaching Network (SEARCH), Maastricht University Medical Center, Maastricht, The Netherlands;
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65
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Abstract
The understanding of the role of the sphingosine 1-phosphate signaling system in immunology and host defense has deepened exponentially over the past 12 years since the discovery that lymphocyte egress was reversibly modulated by sphingosine 1-phosphate receptors, and with the development of fingolimod, a prodrug of a nonselective S1P receptor agonist, for therapeutic use in the treatment of relapsing, remitting multiple sclerosis. Innovative genetic and chemical approaches, together with structural biology, now provide a more detailed molecular understanding of a regulated lysophospholipid ligand with a variety of autocrine, paracrine, and systemic effects in physiology and pathology, based upon selective interactions with a high affinity and selective evolutionary cluster of G-protein-coupled receptors.
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66
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De Luca MA, Valentini V, Bimpisidis Z, Cacciapaglia F, Caboni P, Di Chiara G. Endocannabinoid 2-Arachidonoylglycerol Self-Administration by Sprague-Dawley Rats and Stimulation of in vivo Dopamine Transmission in the Nucleus Accumbens Shell. Front Psychiatry 2014; 5:140. [PMID: 25368584 PMCID: PMC4201088 DOI: 10.3389/fpsyt.2014.00140] [Citation(s) in RCA: 30] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 07/19/2014] [Accepted: 09/23/2014] [Indexed: 01/09/2023] Open
Abstract
2-Arachidonoylglycerol (2-AG) is the most potent endogenous ligand of brain cannabinoid CB1 receptors and is synthesized on demand from 2-arachidonate-containing phosphoinositides by the action of diacylglycerol lipase in response to increased intracellular calcium. Several studies indicate that the endocannabinoid (eCB) system is involved in the mechanism of reward and that diverse drugs of abuse increase brain eCB levels. In addition, eCB are self-administered (SA) by squirrel monkeys, and anandamide increases nucleus accumbens (NAc) shell dopamine (DA) in rats. To date, there is no evidence on the reinforcing effects of 2-AG and its effects on DA transmission in rodents. In order to fill this gap, we studied intravenous 2-AG SA and monitored the effect of 2-AG on extracellular DA in the NAc shell and core via microdialysis in male Sprague-Dawley rats. Rats were implanted with jugular catheters and trained to self-administer 2-AG [25 mg/kg/inf intravenously (iv)] in single daily 1 h sessions for 5 weeks under initial fixed ratio (FR) 1 schedule. The ratio was subsequently increased to FR2. Active nose poking increased from the 6th SA session (acquisition phase) but no significant increase of nose pokes was observed after FR2. When 2-AG was substituted for vehicle (25th SA session, extinction phase), rate responding as well as number of injections slowly decreased. When vehicle was replaced with 2-AG, SA behavior immediately recovered (reacquisition phase). The reinforcing effects of 2-AG in SA behavior were fully blocked by the CB1 receptor inverse agonist/antagonist rimonabant (1 mg/kg intraperitoneally, 30 min before SA session). In the microdialysis studies, we observed that 2-AG (0.1-1.0 mg/kg iv) preferentially stimulates NAc shell as compared to the NAc core. NAc shell DA increased by about 25% over basal value at the highest doses tested (0.5 and 1.0 mg/kg iv). The results obtained suggest that the eCB system, via 2-AG, plays an important role in reward.
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Affiliation(s)
- Maria Antonietta De Luca
- Neuropsychopharmacology Section, Department of Biomedical Sciences, University of Cagliari , Cagliari , Italy ; National Institute of Neuroscience (INN) , Cagliari , Italy
| | - Valentina Valentini
- Neuropsychopharmacology Section, Department of Biomedical Sciences, University of Cagliari , Cagliari , Italy ; National Institute of Neuroscience (INN) , Cagliari , Italy ; Centre of Excellence for Studies on the Neurobiology of Addiction , Cagliari , Italy
| | - Zisis Bimpisidis
- Neuropsychopharmacology Section, Department of Biomedical Sciences, University of Cagliari , Cagliari , Italy
| | - Fabio Cacciapaglia
- Neuropsychopharmacology Section, Department of Biomedical Sciences, University of Cagliari , Cagliari , Italy
| | - Pierluigi Caboni
- Department of Life and Environmental Sciences, University of Cagliari , Cagliari , Italy
| | - Gaetano Di Chiara
- Neuropsychopharmacology Section, Department of Biomedical Sciences, University of Cagliari , Cagliari , Italy ; National Institute of Neuroscience (INN) , Cagliari , Italy ; Centre of Excellence for Studies on the Neurobiology of Addiction , Cagliari , Italy ; Cagliari Section, Neuroscience Institute, National Research Council of Italy , Cagliari , Italy
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67
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Younts TJ, Castillo PE. Endogenous cannabinoid signaling at inhibitory interneurons. Curr Opin Neurobiol 2013; 26:42-50. [PMID: 24650503 DOI: 10.1016/j.conb.2013.12.006] [Citation(s) in RCA: 39] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/07/2013] [Revised: 12/02/2013] [Accepted: 12/04/2013] [Indexed: 11/15/2022]
Abstract
Significant progress has been made in our understanding of how endogenous cannabinoids (eCBs) signal at excitatory and inhibitory synapses in the central nervous system (CNS). This review discusses how eCBs regulate inhibitory interneurons, their synapses, and the networks in which they are embedded. eCB signaling plays a pivotal role in brain physiology by means of their synaptic signal transduction, spatiotemporal signaling profile, routing of information through inhibitory microcircuits, and experience-dependent plasticity. Understanding the normal processes underlying eCB signaling is beginning to shed light on how their dysregulation contributes to disease.
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Affiliation(s)
- Thomas J Younts
- Dominick P. Purpura Department of Neuroscience, Albert Einstein College of Medicine, Bronx, NY 10461, United States
| | - Pablo E Castillo
- Dominick P. Purpura Department of Neuroscience, Albert Einstein College of Medicine, Bronx, NY 10461, United States.
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68
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Flores A, Maldonado R, Berrendero F. Cannabinoid-hypocretin cross-talk in the central nervous system: what we know so far. Front Neurosci 2013; 7:256. [PMID: 24391536 PMCID: PMC3868890 DOI: 10.3389/fnins.2013.00256] [Citation(s) in RCA: 45] [Impact Index Per Article: 4.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/30/2013] [Accepted: 12/09/2013] [Indexed: 12/22/2022] Open
Abstract
Emerging findings suggest the existence of a cross-talk between hypocretinergic and endocannabinoid systems. Although few studies have examined this relationship, the apparent overlap observed in the neuroanatomical distribution of both systems as well as their putative functions strongly point to the existence of such cross-modulation. In agreement, biochemical and functional studies have revealed the existence of heterodimers between CB1 cannabinoid receptor and hypocretin receptor-1, which modulates the cellular localization and downstream signaling of both receptors. Moreover, the activation of hypocretin receptor-1 stimulates the synthesis of 2-arachidonoyl glycerol culminating in the retrograde inhibition of neighboring cells and suggesting that endocannabinoids could contribute to some hypocretin effects. Pharmacological data indicate that endocannabinoids and hypocretins might have common physiological functions in the regulation of appetite, reward and analgesia. In contrast, these neuromodulatory systems seem to play antagonistic roles in the regulation of sleep/wake cycle and anxiety-like responses. The present review attempts to piece together what is known about this interesting interaction and describes its potential therapeutic implications.
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Affiliation(s)
- Africa Flores
- Laboratory of Neuropharmacology, Department of Experimental and Health Sciences, Universitat Pompeu Fabra Barcelona, Spain
| | - Rafael Maldonado
- Laboratory of Neuropharmacology, Department of Experimental and Health Sciences, Universitat Pompeu Fabra Barcelona, Spain
| | - Fernando Berrendero
- Laboratory of Neuropharmacology, Department of Experimental and Health Sciences, Universitat Pompeu Fabra Barcelona, Spain
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69
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Dysregulation of cannabinoid CB1 receptor and associated signaling networks in brains of cocaine addicts and cocaine-treated rodents. Neuroscience 2013; 247:294-308. [DOI: 10.1016/j.neuroscience.2013.05.035] [Citation(s) in RCA: 32] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/05/2013] [Revised: 05/03/2013] [Accepted: 05/20/2013] [Indexed: 01/22/2023]
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70
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Laprairie RB, Kelly MEM, Denovan-Wright EM. Cannabinoids increase type 1 cannabinoid receptor expression in a cell culture model of striatal neurons: implications for Huntington's disease. Neuropharmacology 2013; 72:47-57. [PMID: 23602984 DOI: 10.1016/j.neuropharm.2013.04.006] [Citation(s) in RCA: 32] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/18/2013] [Revised: 03/14/2013] [Accepted: 04/02/2013] [Indexed: 10/27/2022]
Abstract
The type 1 cannabinoid receptor (CB1) is a G protein-coupled receptor that is expressed at high levels in the striatum. Activation of CB1 increases expression of neuronal trophic factors and inhibits neurotransmitter release from GABA-ergic striatal neurons. CB1 mRNA levels can be elevated by treatment with cannabinoids in non-neuronal cells. We wanted to determine whether cannabinoid treatment could induce CB1 expression in a cell culture model of striatal neurons and, if possible, determine the molecular mechanism by which this occurred. We found that treatment of STHdh(7/7) cells with the cannabinoids ACEA, mAEA, and AEA produced a CB1receptor-dependent increase in CB1 promoter activity, mRNA, and protein expression. This response was Akt- and NF-κB-dependent. Because decreased CB1 expression is thought to contribute to the pathogenesis of Huntington's disease (HD), we wanted to determine whether cannabinoids could increase CB1 expression in STHdh(7/111) and (111/111) cells expressing the mutant huntingtin protein. We observed that cannabinoid treatment increased CB1 mRNA levels approximately 10-fold in STHdh(7/111) and (111/111) cells, compared to vehicle treatment. Importantly, cannabinoid treatment improved ATP production, increased the expression of the trophic factor BDNF-2, and the mitochondrial regulator PGC1α, and reduced spontaneous GABA release, in HD cells. Therefore, cannabinoid-mediated increases in CB1 levels could reduce the severity of some molecular pathologies observed in HD.
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Affiliation(s)
- Robert B Laprairie
- Rm 6E Sir Charles Tupper Medical Bldg, Department of Pharmacology, Dalhousie University, 5850 College St., Halifax, NS, Canada B3H 4R2.
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71
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Rosen H, Stevens RC, Hanson M, Roberts E, Oldstone MBA. Sphingosine-1-phosphate and its receptors: structure, signaling, and influence. Annu Rev Biochem 2013; 82:637-62. [PMID: 23527695 DOI: 10.1146/annurev-biochem-062411-130916] [Citation(s) in RCA: 167] [Impact Index Per Article: 15.2] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
Abstract
The sphingosine-1-phosphate (S1P) receptor signaling system has biological and medical importance and is the first lipid G protein-coupled receptor (GPCR) structure to be solved to 2.8-Å resolution. S1P binds to five high-affinity GPCRs generating multiple downstream signals that play essential roles in vascular development and endothelial integrity, control of cardiac rhythm, and routine oral treatment of multiple sclerosis. Genetics, chemistry, and now structural biology have advanced this integrated biochemical system. The S1P receptors have a novel N-terminal fold that occludes access to the binding pocket from the extracellular environment as well as orthosteric and bitopic ligands with very different physicochemical properties. S1P receptors and metabolizing enzymes have been deleted, inducibly deleted, and knocked in as tagged or altered receptors in mice. An array of genetic models allows analysis of integrated receptor function in vivo. We can now directly understand causal relationships among protein expression, signal, and control points in physiology and pathology.
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Affiliation(s)
- Hugh Rosen
- Department of Chemical Physiology and Immunology, The Scripps Research Institute, La Jolla, California 92037, USA.
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72
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Tolerance to hypophagia induced by prolonged treatment with a CB1 antagonist is related to the reversion of anorexigenic neuropeptide gene expression in the hypothalamus. ACTA ACUST UNITED AC 2013; 182:12-8. [DOI: 10.1016/j.regpep.2012.12.004] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/16/2012] [Revised: 10/01/2012] [Accepted: 12/17/2012] [Indexed: 12/23/2022]
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73
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Kim J, Li Y, Watkins BA. Fat to treat fat: emerging relationship between dietary PUFA, endocannabinoids, and obesity. Prostaglandins Other Lipid Mediat 2013; 104-105:32-41. [PMID: 23466458 DOI: 10.1016/j.prostaglandins.2012.11.005] [Citation(s) in RCA: 53] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/15/2012] [Revised: 10/27/2012] [Accepted: 11/20/2012] [Indexed: 12/21/2022]
Abstract
Obesity incidence continues to escalate as a global nutrition and health problem. Scientists and clinicians are engaged in numerous research approaches that include behavior, education, applied nutrition studies and clinical therapies to prevent, control and reverse obesity. The common goal is to identify areas of basic and clinical research to understand aspects of human biology that contribute to obesity. In these approaches recent discoveries in biology and advancing technologies are tools employed to prevent and reverse obesity. The purpose of this review article is to present the current knowledge of key components of the endocannabinoid system that contribute to eating, influence systemic energy metabolism, and dietary factors that alter the responses of ligand binding and activation of cannabinoid receptors. Herein the objectives are to (1) describe the relationship between dietary polyunsaturated fatty acids (PUFA) and obesity, (2) explain the role of this signaling system in obesity, and (3) present areas of consequential future research with dietary long chain PUFA. There are several gaps in the knowledge of the role dietary PUFA play in the tone of the endocannabinoid signaling system involving ligands and receptors. Elucidating the PUFA relationship to signaling tone may explain the presumed overstimulation of signaling believed to contribute to over eating, fat accretion and inflammation. Future research in this endeavor must be hypothesis driven utilizing appropriate models for investigations on dietary PUFA, endocannabinoids and obesity.
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Affiliation(s)
- Jeffrey Kim
- Lipid Chemistry and Molecular Biology Laboratory, Center on Aging, University of Connecticut, Storrs, CT 06269-4004, USA
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74
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Spencer JR, Darbyshire KME, Boucher AA, Kashem MA, Long LE, McGregor IS, Karl T, Arnold JC. Novel molecular changes induced by Nrg1 hypomorphism and Nrg1-cannabinoid interaction in adolescence: a hippocampal proteomic study in mice. Front Cell Neurosci 2013; 7:15. [PMID: 23447498 PMCID: PMC3581856 DOI: 10.3389/fncel.2013.00015] [Citation(s) in RCA: 29] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/30/2012] [Accepted: 02/06/2013] [Indexed: 02/01/2023] Open
Abstract
Neuregulin 1 (NRG1) is linked to an increased risk of developing schizophrenia and cannabis dependence. Mice that are hypomorphic for Nrg1 (Nrg1 HET mice) display schizophrenia-relevant behavioral phenotypes and aberrant expression of serotonin and glutamate receptors. Nrg1 HET mice also display idiosyncratic responses to the main psychoactive constituent of cannabis, Δ9-tetrahydrocannabinol (THC). To gain traction on the molecular pathways disrupted by Nrg1 hypomorphism and Nrg1-cannabinoid interactions we conducted a proteomic study. Adolescent wildtype (WT) and Nrg1 HET mice were exposed to repeated injections of vehicle or THC and their hippocampi were submitted to 2D gel proteomics. Comparison of WT and Nrg1 HET mice identified proteins linked to molecular changes in schizophrenia that have not been previously associated with Nrg1. These proteins are involved in vesicular release of neurotransmitters such as SNARE proteins; enzymes impacting serotonergic neurotransmission, and proteins affecting growth factor expression. Nrg1 HET mice treated with THC expressed a distinct protein expression signature compared to WT mice. Replicating prior findings, THC caused proteomic changes in WT mice suggestive of greater oxidative stress and neurodegeneration. We have previously observed that THC selectively increased hippocampal NMDA receptor binding of adolescent Nrg1 HET mice. Here we observed outcomes consistent with heightened NMDA-mediated glutamatergic neurotransmission. This included differential expression of proteins involved in NMDA receptor trafficking to the synaptic membrane; lipid raft stabilization of synaptic NMDA receptors; and homeostatic responses to dampen excitotoxicity. These findings uncover novel proteins altered in response to Nrg1 hypomorphism and Nrg1-cannabinoid interactions that improves our molecular understanding of Nrg1 signaling and Nrg1-mediated genetic vulnerability to the neurobehavioral effects of cannabinoids.
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Affiliation(s)
- Jarrah R Spencer
- Discipline of Pharmacology, University of Sydney Sydney, NSW, Australia ; Brain and Mind Research Institute, University of Sydney Sydney, NSW, Australia
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75
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Berger WT, Ralph BP, Kaczocha M, Sun J, Balius TE, Rizzo RC, Haj-Dahmane S, Ojima I, Deutsch DG. Targeting fatty acid binding protein (FABP) anandamide transporters - a novel strategy for development of anti-inflammatory and anti-nociceptive drugs. PLoS One 2012; 7:e50968. [PMID: 23236415 PMCID: PMC3517626 DOI: 10.1371/journal.pone.0050968] [Citation(s) in RCA: 114] [Impact Index Per Article: 9.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/10/2012] [Accepted: 10/29/2012] [Indexed: 11/23/2022] Open
Abstract
Fatty acid binding proteins (FABPs), in particular FABP5 and FABP7, have recently been identified by us as intracellular transporters for the endocannabinoid anandamide (AEA). Furthermore, animal studies by others have shown that elevated levels of endocannabinoids resulted in beneficial pharmacological effects on stress, pain and inflammation and also ameliorate the effects of drug withdrawal. Based on these observations, we hypothesized that FABP5 and FABP7 would provide excellent pharmacological targets. Thus, we performed a virtual screening of over one million compounds using DOCK and employed a novel footprint similarity scoring function to identify lead compounds with binding profiles similar to oleic acid, a natural FABP substrate. Forty-eight compounds were purchased based on their footprint similarity scores (FPS) and assayed for biological activity against purified human FABP5 employing a fluorescent displacement-binding assay. Four compounds were found to exhibit approximately 50% inhibition or greater at 10 µM, as good as or better inhibitors of FABP5 than BMS309403, a commercially available inhibitor. The most potent inhibitor, γ-truxillic acid 1-naphthyl ester (ChemDiv 8009-2334), was determined to have Ki value of 1.19±0.01 µM. Accordingly a novel α-truxillic acid 1-naphthyl mono-ester (SB-FI-26) was synthesized and assayed for its inhibitory activity against FABP5, wherein SB-FI-26 exhibited strong binding (Ki 0.93±0.08 µM). Additionally, we found SB-FI-26 to act as a potent anti-nociceptive agent with mild anti-inflammatory activity in mice, which strongly supports our hypothesis that the inhibition of FABPs and subsequent elevation of anandamide is a promising new approach to drug discovery. Truxillic acids and their derivatives were also shown by others to have anti-inflammatory and anti-nociceptive effects in mice and to be the active component of Chinese a herbal medicine (Incarvillea sinensis) used to treat rheumatism and pain in humans. Our results provide a likely mechanism by which these compounds exert their effects.
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Affiliation(s)
- William T Berger
- Chemistry and the Institute of Chemical Biology and Drug Discovery, Stony Brook University, Stony Brook, New York, USA
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76
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Malinowska B, Baranowska-Kuczko M, Schlicker E. Triphasic blood pressure responses to cannabinoids: do we understand the mechanism? Br J Pharmacol 2012; 165:2073-88. [PMID: 22022923 DOI: 10.1111/j.1476-5381.2011.01747.x] [Citation(s) in RCA: 66] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/12/2022] Open
Abstract
The cannabinoids comprise three major classes of substances, including compounds derived from the cannabis plant (e.g. Δ(9) -tetrahydrocannabinol and the chemically related substances CP55940 and HU210), endogenously formed (e.g. anandamide) and synthetic compounds (e.g. WIN55212-2). Beyond their psychotropic effects, cannabinoids have complex effects on blood pressure, including biphasic changes of Δ(9) -tetrahydrocannabinol and WIN55212-2 and an even triphasic effect of anandamide. The differing pattern of blood pressure changes displayed by the three types of compounds is not really surprising since, although they share an agonistic effect at cannabinoid CB(1) and CB(2) receptors, some compounds have additional effects. In particular, anandamide is known for its pleiotropic effects, and there is overwhelming evidence that anandamide influences blood pressure via (i) CB(1) receptors, (ii) TRPV1 receptors, (iii) endothelial cannabinoid receptors and (iv) degradation products. This review is dedicated to the description of the effects of externally added cannabinoids on cardiovascular parameters in vivo. First, the cardiovascular effects of cannabinoids in anaesthetized animals will be highlighted since most data have been generated in experiments of that type. The text will follow the three phases of anandamide on blood pressure, and we will check to which extent cardiovascular changes elicited by other cannabinoids show overlap with those effects or differ. The second part will be dedicated to the cardiovascular effects of the cannabinoids in conscious animals. In the third part, cardiovascular effects in humans will be discussed, and similarities and differences with respect to the data from animals will be examined.
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Affiliation(s)
- Barbara Malinowska
- Zakład Fizjologii i Patofizjologii Doświadczalnej, Uniwersytet Medyczny w Białymstoku, ul. Mickiewicza 2A, Białystok, Poland
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77
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Gaffuri AL, Ladarre D, Lenkei Z. Type-1 cannabinoid receptor signaling in neuronal development. Pharmacology 2012; 90:19-39. [PMID: 22776780 DOI: 10.1159/000339075] [Citation(s) in RCA: 61] [Impact Index Per Article: 5.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/13/2012] [Accepted: 04/13/2012] [Indexed: 01/21/2023]
Abstract
The type-1 cannabinoid receptor (CB1R) was initially identified as the neuronal target of Δ(9)-tetrahydrocannabinol (THC), the major psychoactive substance of marijuana. This receptor is one of the most abundant G-protein-coupled receptors in the adult brain, the target of endocannabinoid ligands and a well-characterized retrograde synaptic regulator. However, CB1Rs are also highly and often transiently expressed in neuronal populations in the embryonic and early postnatal brain, even before the formation of synapses. This suggests important physiological roles for CB1Rs during neuronal development. Several recent reviews have summarized our knowledge about the role of the endocannabinoid (eCB) system in neurodevelopment and neurotransmission by focusing on the metabolism of endocannabinoid molecules. Here, we review current knowledge about the effects of the modulation of CB1R signaling during the different phases of brain development. More precisely, we focus on reports that directly implicate CB1Rs during progenitor cell migration and differentiation, neurite outgrowth, axonal pathfinding and synaptogenesis. Based on theoretical considerations and on the reviewed experimental data, we propose a new model to explain the diversity of experimental findings on eCB signaling on neurite growth and axonal pathfinding. In our model, cell-autonomus and paracrine eCBs acting on CB1Rs are part of a global inhibitory network of cytoskeletal effectors, which act in concert with positive-feedback local-excitation loops, to ultimately yield highly polarized neurons.
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Affiliation(s)
- Anne-Lise Gaffuri
- Neurobiology Laboratory, ESPCI-ParisTech, ESPCI-CNRS UMR 7637, Paris, France
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78
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Console-Bram L, Marcu J, Abood ME. Cannabinoid receptors: nomenclature and pharmacological principles. Prog Neuropsychopharmacol Biol Psychiatry 2012; 38:4-15. [PMID: 22421596 PMCID: PMC3378782 DOI: 10.1016/j.pnpbp.2012.02.009] [Citation(s) in RCA: 105] [Impact Index Per Article: 8.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 10/10/2011] [Revised: 02/20/2012] [Accepted: 02/20/2012] [Indexed: 02/06/2023]
Abstract
The CB1 and CB2 cannabinoid receptors are members of the G protein-coupled receptor (GPCR) family that are pharmacologically well defined. However, the discovery of additional sites of action for endocannabinoids as well as synthetic cannabinoid compounds suggests the existence of additional cannabinoid receptors. Here we review this evidence, as well as the current nomenclature for classifying a target as a cannabinoid receptor. Basic pharmacological definitions, principles and experimental conditions are discussed in order to place in context the mechanisms underlying cannabinoid receptor activation. Constitutive (agonist-independent) activity is observed with the overexpression of many GPCRs, including cannabinoid receptors. Allosteric modulators can alter the pharmacological responses of cannabinoid receptors. The complex molecular architecture of each of the cannabinoid receptors allows for a single receptor to recognize multiple classes of compounds and produce an array of distinct downstream effects. Natural polymorphisms and alternative splice variants may also contribute to their pharmacological diversity. As our knowledge of the distinct differences grows, we may be able to target select receptor conformations and their corresponding pharmacological responses. Importantly, the basic biology of the endocannabinoid system will continue to be revealed by ongoing investigations.
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Affiliation(s)
- Linda Console-Bram
- Center for Substance Abuse Research, Temple University School of Medicine, Philadelphia, PA, USA 19140
| | - Jahan Marcu
- Center for Substance Abuse Research, Temple University School of Medicine, Philadelphia, PA, USA 19140,Department of Anatomy and Cell Biology, Temple University School of Medicine, Philadelphia, PA, USA 19140
| | - Mary E. Abood
- Center for Substance Abuse Research, Temple University School of Medicine, Philadelphia, PA, USA 19140,Department of Anatomy and Cell Biology, Temple University School of Medicine, Philadelphia, PA, USA 19140
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79
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Kaczocha M, Lin Q, Nelson LD, McKinney MK, Cravatt BF, London E, Deutsch DG. Anandamide externally added to lipid vesicles containing trapped fatty acid amide hydrolase (FAAH) is readily hydrolyzed in a sterol-modulated fashion. ACS Chem Neurosci 2012; 3:364-8. [PMID: 22860204 DOI: 10.1021/cn300001w] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/05/2012] [Accepted: 01/18/2012] [Indexed: 11/30/2022] Open
Abstract
We show that anandamide (AEA) externally added to model membrane vesicles containing trapped fatty acid amide hydrolyase (FAAH) can be readily hydrolyzed, demonstrating facile, rapid anandamide movement across the lipid bilayer. The rate of hydrolysis is significantly facilitated by cholesterol and coprostanol, but not by cholesterol sulfate. The effects of sterol upon hydrolysis by FAAH bound to the outer surface of the bilayer were much smaller, although they followed the same pattern. We propose the facilitation of hydrolysis is a combination of the effects of sterol on accessibility of membrane-inserted endocannabinoids to surface protein, and on the rate of endocannabinod transport across the membrane bilayer.
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Affiliation(s)
- Martin Kaczocha
- Department of Biochemistry and
Cell Biology, Stony Brook University, Stony
Brook, New York 11794, United States
| | - Qingqing Lin
- Department of Biochemistry and
Cell Biology, Stony Brook University, Stony
Brook, New York 11794, United States
| | - Lindsay D. Nelson
- Department of Biochemistry and
Cell Biology, Stony Brook University, Stony
Brook, New York 11794, United States
| | - Michelle K. McKinney
- Department of Chemical Physiology, The Scripps Research Institute, La Jolla, California
92037, United States
| | - Benjamin F. Cravatt
- Department of Chemical Physiology, The Scripps Research Institute, La Jolla, California
92037, United States
| | - Erwin London
- Department of Biochemistry and
Cell Biology, Stony Brook University, Stony
Brook, New York 11794, United States
| | - Dale G. Deutsch
- Department of Biochemistry and
Cell Biology, Stony Brook University, Stony
Brook, New York 11794, United States
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80
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Karl T, Cheng D, Garner B, Arnold JC. The therapeutic potential of the endocannabinoid system for Alzheimer's disease. Expert Opin Ther Targets 2012; 16:407-20. [PMID: 22448595 DOI: 10.1517/14728222.2012.671812] [Citation(s) in RCA: 28] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/05/2022]
Abstract
INTRODUCTION Dementia currently affects over 35 million people worldwide. The most common form of dementia is Alzheimer's disease (AD). Currently, treatments for AD do not stop or reverse the progression of the disease and they are accompanied by side effects. AREAS COVERED The main features of AD pathology, treatment options currently available, the endocannabinoid system and its functionality in general and its role in AD pathology in detail will be outlined. A particular focus will be on the therapeutic potential of the phytocannabinoid cannabidiol. EXPERT OPINION Based on the complex pathology of AD, a preventative, multimodal drug approach targeting a combination of pathological AD symptoms appears ideal. Importantly, cannabinoids show anti-inflammatory, neuroprotective and antioxidant properties and have immunosuppressive effects. Thus, the cannabinoid system should be a prime target for AD therapy. The cannabinoid receptor 2 appears to be a promising candidate but its role in AD has to be investigated cautiously. Furthermore, the phytocannabinoid cannabidiol is of particular interest as it lacks the psychoactive and cognition-impairing properties of other cannabinoids. In conclusion, future research should focus on the evaluation of the effects of manipulations to the endocannabinoid system in established animal models for AD, combined with early-phase studies in humans.
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Affiliation(s)
- Tim Karl
- Neuroscience Research Australia, Randwick, NSW, Australia.
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81
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The endocannabinoid system: a revolving plate in neuro-immune interaction in health and disease. Amino Acids 2012; 45:95-112. [PMID: 22367605 DOI: 10.1007/s00726-012-1252-8] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/02/2011] [Accepted: 02/14/2012] [Indexed: 12/21/2022]
Abstract
Studies of the last 40 years have brought to light an important physiological network, the endocannabinoid system. Endogenous and exogenous cannabinoids mediate their effects through activation of specific cannabinoid receptors. This modulatory homoeostatic system operates in the regulation of brain function and also in the periphery. The cannabinoid system has been shown to be involved in regulating the immune system. Studies examining the effect of cannabinoid-based drugs on immunity have shown that many cellular and cytokine mechanisms are modulated by these agents, thus raising the hypothesis that these compounds may be of value in the management of chronic inflammatory diseases. The special properties of endocannabinoids as neurotransmitters, their pleiotropic effects and the impact on immune function show that the endocannabinoid system represents a revolving plate of neural and immune interactions. In this paper, we outline current information on immune effects of cannabinoids in health and disease.
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82
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Kleyer J, Nicolussi S, Taylor P, Simonelli D, Furger E, Anderle P, Gertsch J. Cannabinoid receptor trafficking in peripheral cells is dynamically regulated by a binary biochemical switch. Biochem Pharmacol 2012; 83:1393-412. [PMID: 22387618 DOI: 10.1016/j.bcp.2012.02.014] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/18/2012] [Revised: 02/16/2012] [Accepted: 02/17/2012] [Indexed: 12/20/2022]
Abstract
The cannabinoid G protein-coupled receptors (GPCRs) CB₁ and CB₂ are expressed in different peripheral cells. Localization of GPCRs in the cell membrane determines signaling via G protein pathways. Here we show that unlike in transfected cells, CB receptors in cell lines and primary human cells are not internalized upon agonist interaction, but move between cytoplasm and cell membranes by ligand-independent trafficking mechanisms. Even though CB receptors are expressed in many cells of peripheral origin they are not always localized in the cell membrane and in most cancer cell lines the ratios between CB₁ and CB₂ receptor gene and surface expression vary significantly. In contrast, CB receptor cell surface expression in HL60 cells is subject to significant oscillations and CB₂ receptors form oligomers and heterodimers with CB₁ receptors, showing synchronized surface expression, localization and trafficking. We show that hydrogen peroxide and other nonspecific protein tyrosine phosphatase inhibitors (TPIs) such as phenylarsine oxide trigger both CB₂ receptor internalization and externalization, depending on receptor localization. Phorbol ester-mediated internalization of CB receptors can be inhibited via this switch. In primary human immune cells hydrogen peroxide and other TPIs lead to a robust internalization of CB receptors in monocytes and an externalization in T cells. This study describes, for the first time, the dynamic nature of CB receptor trafficking in the context of a biochemical switch, which may have implications for studies on the cell-type specific effects of cannabinoids and our understanding of the regulation of CB receptor cell surface expression.
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Affiliation(s)
- Jonas Kleyer
- Institute of Biochemistry and Molecular Medicine, Swiss National Centre of Competence in Research NCCR TransCure, University of Bern, Bühlstrasse 28, CH-3012 Bern, Switzerland
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83
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Janero DR. Cannabinoid-1 receptor (CB1R) blockers as medicines: beyond obesity and cardiometabolic disorders to substance abuse/drug addiction with CB1R neutral antagonists. Expert Opin Emerg Drugs 2012; 17:17-29. [DOI: 10.1517/14728214.2012.660916] [Citation(s) in RCA: 30] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/28/2022]
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84
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The biology that underpins the therapeutic potential of cannabis-based medicines for the control of spasticity in multiple sclerosis. Mult Scler Relat Disord 2012; 1:64-75. [PMID: 25876933 DOI: 10.1016/j.msard.2011.11.001] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/15/2011] [Accepted: 11/17/2011] [Indexed: 12/14/2022]
Abstract
Cannabis-based medicines have recently been approved for the treatment of pain and spasticity in multiple sclerosis (MS). This supports the original perceptions of people with MS, who were using illegal street cannabis for symptom control and pre-clinical testing in animal models of MS. This activity is supported both by the biology of the disease and the biology of the cannabis plant and the endocannabinoid system. MS results from disease that impairs neurotransmission and this is controlled by cannabinoid receptors and endogenous cannabinoid ligands. This can limit spasticity and may also influence the processes that drive the accumulation of progressive disability.
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85
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86
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Kaczocha M, Vivieca S, Sun J, Glaser ST, Deutsch DG. Fatty acid-binding proteins transport N-acylethanolamines to nuclear receptors and are targets of endocannabinoid transport inhibitors. J Biol Chem 2011; 287:3415-24. [PMID: 22170058 DOI: 10.1074/jbc.m111.304907] [Citation(s) in RCA: 141] [Impact Index Per Article: 10.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/28/2023] Open
Abstract
N-acylethanolamines (NAEs) are bioactive lipids that engage diverse receptor systems. Recently, we identified fatty acid-binding proteins (FABPs) as intracellular NAE carriers. Here, we provide two new functions for FABPs in NAE signaling. We demonstrate that FABPs mediate the nuclear translocation of the NAE oleoylethanolamide, an agonist of nuclear peroxisome proliferator-activated receptor α (PPARα). Antagonism of FABP function through chemical inhibition, dominant-negative approaches, or shRNA-mediated knockdown reduced PPARα activation, confirming a requisite role for FABPs in this process. In addition, we show that NAE analogs, traditionally employed as inhibitors of the putative endocannabinoid transmembrane transporter, target FABPs. Support for the existence of the putative membrane transporter stems primarily from pharmacological inhibition of endocannabinoid uptake by such transport inhibitors, which are widely employed in endocannabinoid research despite lacking a known cellular target(s). Our approach adapted FABP-mediated PPARα signaling and employed in vitro binding, arachidonoyl-[1-(14)C]ethanolamide ([(14)C]AEA) uptake, and FABP knockdown to demonstrate that transport inhibitors exert their effects through inhibition of FABPs, thereby providing a molecular rationale for the underlying physiological effects of these compounds. Identification of FABPs as targets of transport inhibitors undermines the central pharmacological support for the existence of an endocannabinoid transmembrane transporter.
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Affiliation(s)
- Martin Kaczocha
- Department of Biochemistry and Cell Biology, Stony Brook University, Stony Brook, New York 11794-5215, USA.
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87
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Rorato R, Reis WL, de Carvalho Borges B, Antunes-Rodrigues J, Elias LLK. Cannabinoid CB₁ receptor restrains accentuated activity of hypothalamic corticotropin-releasing factor and brainstem tyrosine hydroxylase neurons in endotoxemia-induced hypophagia in rats. Neuropharmacology 2011; 63:154-60. [PMID: 22138163 DOI: 10.1016/j.neuropharm.2011.11.009] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/03/2011] [Revised: 11/02/2011] [Accepted: 11/18/2011] [Indexed: 10/14/2022]
Abstract
It is well known that endocannabinoids play an important role in the regulation of food intake and body weight. Endocannabinoids and cannabinoid receptors are found in the hypothalamus and brainstem, which are central areas involved in the control of food intake and energy expenditure. Activation of these areas is related to hypophagia observed during inflammatory stimulus. This study investigated the effects of cannabinoid (CB₁) receptor blockade on lipopolysaccharide (LPS)-induced hypophagia. Male Wistar rats were pretreated with rimonabant (10 mg/kg, by gavage) or vehicle; 30 min later they received an injection of either LPS (100 μg/kg, intraperitoneal) or saline. Food intake, body weight, corticosterone response, CRF and CART mRNA expression, Fos-CRF and Fos-α-MSH immunoreactivity in the hypothalamus and Fos-tyrosine hydroxylase (TH) immunoreactivity in the brainstem were evaluated. LPS administration decreased food intake and body weight gain and increased plasma corticosterone levels and CRF mRNA expression in the PVN. We also observed an increase in Fos-CRF and Fos-TH double-labeled neurons after LPS injection in vehicle-pretreated rats, with no changes in CART mRNA or Fos-α-MSH immunoreactive neurons in the ARC. In saline-treated animals, rimonabant pretreatment decreased food intake and body weight gain but did not modify hormone response or Fos expression in the hypothalamus and brainstem compared with vehicle-pretreated rats. Rimonabant pretreatment potentiated LPS-induced hypophagia, body weight loss and Fos-CRF and Fos-TH expressing neurons. Rimonabant did not modify corticosterone, CRF mRNA or Fos-α-MSH responses in rats treated with LPS. These data suggest that the endocannabinoid system, mediated by CB₁ receptors, modulates hypothalamic and brainstem circuitry underlying the hypophagic effect during endotoxemia to prevent an exaggerated food intake decrease. This article is part of a Special Issue entitled 'Central Control of Food Intake'.
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Affiliation(s)
- Rodrigo Rorato
- Department of Physiology, School of Medicine of Ribeirao Preto, University of Sao Paulo, Avenida Bandeirantes 3900, 14049-900 Ribeirao Preto, Sao Paulo, Brazil
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88
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Erdozain AM, Diez-Alarcia R, Meana JJ, Callado LF. The inverse agonist effect of rimonabant on G protein activation is not mediated by the cannabinoid CB1 receptor: evidence from postmortem human brain. Biochem Pharmacol 2011; 83:260-8. [PMID: 22093909 DOI: 10.1016/j.bcp.2011.10.018] [Citation(s) in RCA: 22] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/07/2011] [Revised: 10/27/2011] [Accepted: 10/27/2011] [Indexed: 01/28/2023]
Abstract
Rimonabant (SR141716) was the first potent and selective cannabinoid CB1 receptor antagonist synthesized. Several data support that rimonabant behaves as an inverse agonist. Moreover, there is evidence suggesting that this inverse agonism may be CB1 receptor-independent. The aim of the present study was to elucidate whether the effect of rimonabant over G protein activation in postmortem human brain is CB1 dependent or independent. [(35)S]GTPγS binding assays and antibody-capture [(35)S]GTPγS scintillation proximity assays (SPA) were performed in human and mice brain. [(3)H]SR141716 binding characteristics were also studied. Rimonabant concentration-dependently decreased basal [(35)S]GTPγS binding to human cortical membranes. This effect did not change in the presence of either the CB1 receptor agonist WIN 55,212-2, the CB1 receptor neutral antagonist O-2050, or the CB1 allosteric modulator Org 27569. [(35)S]GTPγS binding assays performed in CB1 knockout mice brains revealed that rimonabant inhibited the [(35)S]GTPγS binding in the same manner as it did in wild-type mice. The SPA combined with the use of specific antibody-capture of G(α) specific subunits showed that rimonabant produces its inverse agonist effect through G(i3), G(o) and G(z) subtypes. This effect was not inhibited by the CB1 receptor antagonist O-2050. Finally, [(3)H]SR141716 binding assays in human cortical membranes demonstrated that rimonabant recognizes an additional binding site other than the CB1 receptor orthosteric binding site recognized by O-2050. This study provides new data demonstrating that at least the inverse agonist effect observed with >1μM concentrations of rimonabant in [(35)S]GTPγS binding assays is not mediated by the CB1 receptor in human brain.
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Affiliation(s)
- A M Erdozain
- Department of Pharmacology, University of the Basque Country E-48940 Leioa, Bizkaia, Spain
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