101
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Tortoriello G, Rhodes BP, Takacs SM, Stuart JM, Basnet A, Raboune S, Widlanski TS, Doherty P, Harkany T, Bradshaw HB. Targeted lipidomics in Drosophila melanogaster identifies novel 2-monoacylglycerols and N-acyl amides. PLoS One 2013; 8:e67865. [PMID: 23874457 PMCID: PMC3708943 DOI: 10.1371/journal.pone.0067865] [Citation(s) in RCA: 59] [Impact Index Per Article: 5.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/22/2012] [Accepted: 05/28/2013] [Indexed: 11/19/2022] Open
Abstract
Lipid metabolism is critical to coordinate organ development and physiology in response to tissue-autonomous signals and environmental cues. Changes to the availability and signaling of lipid mediators can limit competitiveness, adaptation to environmental stressors, and augment pathological processes. Two classes of lipids, the N-acyl amides and the 2-acyl glycerols, have emerged as important signaling molecules in a wide range of species with important signaling properties, though most of what is known about their cellular functions is from mammalian models. Therefore, expanding available knowledge on the repertoire of these lipids in invertebrates will provide additional avenues of research aimed at elucidating biosynthetic, metabolic, and signaling properties of these molecules. Drosophila melanogaster is a commonly used organism to study intercellular communication, including the functions of bioactive lipids. However, limited information is available on the molecular identity of lipids with putative biological activities in Drosophila. Here, we used a targeted lipidomics approach to identify putative signaling lipids in third instar Drosophila larvae, possessing particularly large lipid mass in their fat body. We identified 2-linoleoyl glycerol, 2-oleoyl glycerol, and 45 N-acyl amides in larval tissues, and validated our findings by the comparative analysis of Oregon-RS, Canton-S and w1118 strains. Data here suggest that Drosophila represent another model system to use for the study of 2-acyl glycerol and N-acyl amide signaling.
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Affiliation(s)
- Giuseppe Tortoriello
- Division of Molecular Neurobiology, Department of Medical Biochemistry and Biophysics, Karolinska Institutet, Stockholm, Sweden
| | - Brandon P. Rhodes
- Psychological and Brain Sciences, Indiana University, Bloomington, Indiana, United States of America
| | - Sara M. Takacs
- Psychological and Brain Sciences, Indiana University, Bloomington, Indiana, United States of America
| | - Jordyn M. Stuart
- Psychological and Brain Sciences, Indiana University, Bloomington, Indiana, United States of America
| | - Arjun Basnet
- Department of Chemistry, Indiana University, Bloomington, Indiana, United States of America
| | - Siham Raboune
- Psychological and Brain Sciences, Indiana University, Bloomington, Indiana, United States of America
| | - Theodore S. Widlanski
- Department of Chemistry, Indiana University, Bloomington, Indiana, United States of America
| | - Patrick Doherty
- Wolfson Centre for Ageing-Related Diseases, King’s College London, London, United Kingdom
| | - Tibor Harkany
- Division of Molecular Neurobiology, Department of Medical Biochemistry and Biophysics, Karolinska Institutet, Stockholm, Sweden
- European Neuroscience Institute, University of Aberdeen, Aberdeen, United Kingdom
| | - Heather B. Bradshaw
- Psychological and Brain Sciences, Indiana University, Bloomington, Indiana, United States of America
- * E-mail:
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102
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Silvestri C, Martella A, Poloso NJ, Piscitelli F, Capasso R, Izzo A, Woodward DF, Di Marzo V. Anandamide-derived prostamide F2α negatively regulates adipogenesis. J Biol Chem 2013; 288:23307-21. [PMID: 23801328 DOI: 10.1074/jbc.m113.489906] [Citation(s) in RCA: 40] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/15/2022] Open
Abstract
Lipid mediators variedly affect adipocyte differentiation. Anandamide stimulates adipogenesis via CB1 receptors and peroxisome proliferator-activated receptor γ. Anandamide may be converted by PTGS2 (COX2) and prostaglandin F synthases, such as prostamide/prostaglandin F synthase, to prostaglandin F2α ethanolamide (PGF2αEA), of which bimatoprost is a potent synthetic analog. PGF2αEA/bimatoprost act via prostaglandin F2αFP receptor/FP alt4 splicing variant heterodimers. We investigated whether prostamide signaling occurs in preadipocytes and controls adipogenesis. Exposure of mouse 3T3-L1 or human preadipocytes to PGF2αEA/bimatoprost during early differentiation inhibits adipogenesis. PGF2αEA is produced from anandamide in preadipocytes and much less so in differentiating adipocytes, which express much less PTGS2, FP, and its alt4 splicing variant. Selective antagonism of PGF2αEA receptors counteracts prostamide effects on adipogenesis, as does inhibition of ERK1/2 phosphorylation. Selective inhibition of PGF2αEA versus prostaglandin F2α biosynthesis accelerates adipogenesis. PGF2αEA levels are reduced in the white adipose tissue of high fat diet-fed mice where there is a high requirement for new adipocytes. Prostamides also inhibit zebrafish larval adipogenesis in vivo. We propose that prostamide signaling in preadipocytes is a novel anandamide-derived antiadipogenic mechanism.
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Affiliation(s)
- Cristoforo Silvestri
- Endocannabinoid Research Group, Institute of Biomolecular Chemistry, Consiglio Nazionale delle Ricerche, Via Campi Flegrei 34, 80078 Pozzuoli, Italy
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103
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Fagundo AB, de la Torre R, Jiménez-Murcia S, Agüera Z, Pastor A, Casanueva FF, Granero R, Baños R, Botella C, del Pino-Gutierrez A, Fernández-Real JM, Fernández-García JC, Frühbeck G, Gómez-Ambrosi J, Menchón JM, Moragrega I, Rodríguez R, Tárrega S, Tinahones FJ, Fernández-Aranda F. Modulation of the Endocannabinoids N-Arachidonoylethanolamine (AEA) and 2-Arachidonoylglycerol (2-AG) on Executive Functions in Humans. PLoS One 2013; 8:e66387. [PMID: 23840456 PMCID: PMC3686875 DOI: 10.1371/journal.pone.0066387] [Citation(s) in RCA: 25] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/25/2013] [Accepted: 05/05/2013] [Indexed: 12/20/2022] Open
Abstract
Animal studies point to an implication of the endocannabinoid system on executive functions. In humans, several studies have suggested an association between acute or chronic use of exogenous cannabinoids (Δ9-tetrahydrocannabinol) and executive impairments. However, to date, no published reports establish the relationship between endocannabinoids, as biomarkers of the cannabinoid neurotransmission system, and executive functioning in humans. The aim of the present study was to explore the association between circulating levels of plasma endocannabinoids N-arachidonoylethanolamine (AEA) and 2-Arachidonoylglycerol (2-AG) and executive functions (decision making, response inhibition and cognitive flexibility) in healthy subjects. One hundred and fifty seven subjects were included and assessed with the Wisconsin Card Sorting Test; Stroop Color and Word Test; and Iowa Gambling Task. All participants were female, aged between 18 and 60 years and spoke Spanish as their first language. Results showed a negative correlation between 2-AG and cognitive flexibility performance (r = −.37; p<.05). A positive correlation was found between AEA concentrations and both cognitive flexibility (r = .59; p<.05) and decision making performance (r = .23; P<.05). There was no significant correlation between either 2-AG (r = −.17) or AEA (r = −.08) concentrations and inhibition response. These results show, in humans, a relevant modulation of the endocannabinoid system on prefrontal-dependent cognitive functioning. The present study might have significant implications for the underlying executive alterations described in some psychiatric disorders currently associated with endocannabinoids deregulation (namely drug abuse/dependence, depression, obesity and eating disorders). Understanding the neurobiology of their dysexecutive profile might certainly contribute to the development of new treatments and pharmacological approaches.
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Affiliation(s)
- Ana B. Fagundo
- Department of Psychiatry, University Hospital of Bellvitge-IDIBELL, Barcelona, Spain
- CIBER Fisiopatología Obesidad y Nutrición (CIBERObn), Instituto Salud Carlos III, Barcelona, Spain
| | - Rafael de la Torre
- CIBER Fisiopatología Obesidad y Nutrición (CIBERObn), Instituto Salud Carlos III, Barcelona, Spain
- Human Pharmacology and Clinical Neurosciences Research Group, Neuroscience Research Program, IMIM (Hospital del Mar Medical Research Institute), Barcelona, Spain
| | - Susana Jiménez-Murcia
- Department of Psychiatry, University Hospital of Bellvitge-IDIBELL, Barcelona, Spain
- CIBER Fisiopatología Obesidad y Nutrición (CIBERObn), Instituto Salud Carlos III, Barcelona, Spain
- Department of Clinical Sciences, School of Medicine, University of Barcelona, Barcelona, Spain
| | - Zaida Agüera
- CIBER Fisiopatología Obesidad y Nutrición (CIBERObn), Instituto Salud Carlos III, Barcelona, Spain
| | - Antoni Pastor
- Human Pharmacology and Clinical Neurosciences Research Group, Neuroscience Research Program, IMIM (Hospital del Mar Medical Research Institute), Barcelona, Spain
- Department of Pharmacology, School of Medicine, Universitat Autònoma de Barcelona, Barcelona, Spain
| | - Felipe F. Casanueva
- CIBER Fisiopatología Obesidad y Nutrición (CIBERObn), Instituto Salud Carlos III, Barcelona, Spain
- Endocrine Division, Complejo Hospitalario U. de Santiago, Santiago de Compostela University, Santiago de Compostela, Spain
| | - Roser Granero
- CIBER Fisiopatología Obesidad y Nutrición (CIBERObn), Instituto Salud Carlos III, Barcelona, Spain
- Departament de Psicobiologia i Metodologia, Universitat Autònoma de Barcelona, Barcelona, Spain
| | - Rosa Baños
- CIBER Fisiopatología Obesidad y Nutrición (CIBERObn), Instituto Salud Carlos III, Barcelona, Spain
- Department of Personality, Evaluation and Psychological Treatment of the University of Valencia, Valencia, Spain
| | - Cristina Botella
- CIBER Fisiopatología Obesidad y Nutrición (CIBERObn), Instituto Salud Carlos III, Barcelona, Spain
- Department of Basic Psychology, Clinic and Psychobiology of the University Jaume I, Castelló, Spain
| | - Amparo del Pino-Gutierrez
- Department of Psychiatry, University Hospital of Bellvitge-IDIBELL, Barcelona, Spain
- Nursing Department of Public Health, Maternal and Child Health the Nursing School of the University of Barcelona, Barcelona, Spain
| | - Jose M. Fernández-Real
- CIBER Fisiopatología Obesidad y Nutrición (CIBERObn), Instituto Salud Carlos III, Barcelona, Spain
- Department of Diabetes, Endocrinology and Nutrition, Institut d’Investigació Biomèdica de Girona (IdlBGi) Hospital Dr Josep Trueta, Girona, Spain
| | - Jose C. Fernández-García
- CIBER Fisiopatología Obesidad y Nutrición (CIBERObn), Instituto Salud Carlos III, Barcelona, Spain
- Department of Endocrinology and Nutrition, Hospital Clínico Universitario Virgen de Victoria, Málaga, Spain
| | - Gema Frühbeck
- CIBER Fisiopatología Obesidad y Nutrición (CIBERObn), Instituto Salud Carlos III, Barcelona, Spain
- Department of Endocrinology and Nutrition, Clínica Universidad de Navarra, University of Navarra, Pamplona, Spain
| | - Javier Gómez-Ambrosi
- CIBER Fisiopatología Obesidad y Nutrición (CIBERObn), Instituto Salud Carlos III, Barcelona, Spain
- Department of Endocrinology and Nutrition, Clínica Universidad de Navarra, University of Navarra, Pamplona, Spain
| | - José M. Menchón
- Department of Psychiatry, University Hospital of Bellvitge-IDIBELL, Barcelona, Spain
- Department of Clinical Sciences, School of Medicine, University of Barcelona, Barcelona, Spain
- CIBER Salud Mental (CIBERsam), Instituto Salud Carlos III, Barcelona, Spain
| | - Inés Moragrega
- CIBER Fisiopatología Obesidad y Nutrición (CIBERObn), Instituto Salud Carlos III, Barcelona, Spain
- Department of Basic Psychology, Clinic and Psychobiology of the University Jaume I, Castelló, Spain
| | - Roser Rodríguez
- CIBER Fisiopatología Obesidad y Nutrición (CIBERObn), Instituto Salud Carlos III, Barcelona, Spain
- Department of Diabetes, Endocrinology and Nutrition, Institut d’Investigació Biomèdica de Girona (IdlBGi) Hospital Dr Josep Trueta, Girona, Spain
| | - Salomé Tárrega
- Departament de Psicobiologia i Metodologia, Universitat Autònoma de Barcelona, Barcelona, Spain
| | - Francisco J. Tinahones
- CIBER Fisiopatología Obesidad y Nutrición (CIBERObn), Instituto Salud Carlos III, Barcelona, Spain
- Department of Endocrinology and Nutrition, Hospital Clínico Universitario Virgen de Victoria, Málaga, Spain
| | - Fernando Fernández-Aranda
- Department of Psychiatry, University Hospital of Bellvitge-IDIBELL, Barcelona, Spain
- CIBER Fisiopatología Obesidad y Nutrición (CIBERObn), Instituto Salud Carlos III, Barcelona, Spain
- Department of Clinical Sciences, School of Medicine, University of Barcelona, Barcelona, Spain
- * E-mail:
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104
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Vincenzi F, Targa M, Corciulo C, Tabrizi MA, Merighi S, Gessi S, Saponaro G, Baraldi PG, Borea PA, Varani K. Antinociceptive effects of the selective CB2 agonist MT178 in inflammatory and chronic rodent pain models. Pain 2013; 154:864-73. [DOI: 10.1016/j.pain.2013.02.007] [Citation(s) in RCA: 51] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/30/2012] [Revised: 01/07/2013] [Accepted: 02/19/2013] [Indexed: 11/25/2022]
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105
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Obesity-driven synaptic remodeling affects endocannabinoid control of orexinergic neurons. Proc Natl Acad Sci U S A 2013; 110:E2229-38. [PMID: 23630288 DOI: 10.1073/pnas.1219485110] [Citation(s) in RCA: 112] [Impact Index Per Article: 10.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/25/2022] Open
Abstract
Acute or chronic alterations in energy status alter the balance between excitatory and inhibitory synaptic transmission and associated synaptic plasticity to allow for the adaptation of energy metabolism to new homeostatic requirements. The impact of such changes on endocannabinoid and cannabinoid receptor type 1 (CB1)-mediated modulation of synaptic transmission and strength is not known, despite the fact that this signaling system is an important target for the development of new drugs against obesity. We investigated whether CB1-expressing excitatory vs. inhibitory inputs to orexin-A-containing neurons in the lateral hypothalamus are altered in obesity and how this modifies endocannabinoid control of these neurons. In lean mice, these inputs are mostly excitatory. By confocal and ultrastructural microscopic analyses, we observed that in leptin-knockout (ob/ob) obese mice, and in mice with diet-induced obesity, orexinergic neurons receive predominantly inhibitory CB1-expressing inputs and overexpress the biosynthetic enzyme for the endocannabinoid 2-arachidonoylglycerol, which retrogradely inhibits synaptic transmission at CB1-expressing axon terminals. Patch-clamp recordings also showed increased CB1-sensitive inhibitory innervation of orexinergic neurons in ob/ob mice. These alterations are reversed by leptin administration, partly through activation of the mammalian target of rapamycin pathway in neuropeptide-Y-ergic neurons of the arcuate nucleus, and are accompanied by CB1-mediated enhancement of orexinergic innervation of target brain areas. We propose that enhanced inhibitory control of orexin-A neurons, and their CB1-mediated disinhibition, are a consequence of leptin signaling impairment in the arcuate nucleus. We also provide initial evidence of the participation of this phenomenon in hyperphagia and hormonal dysregulation in obesity.
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106
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Di Marzo V, De Petrocellis L. Why do cannabinoid receptors have more than one endogenous ligand? Philos Trans R Soc Lond B Biol Sci 2013; 367:3216-28. [PMID: 23108541 DOI: 10.1098/rstb.2011.0382] [Citation(s) in RCA: 209] [Impact Index Per Article: 19.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/04/2023] Open
Abstract
The endocannabinoid system was revealed following the understanding of the mechanism of action of marijuana's major psychotropic principle, Δ(9)-tetrahydrocannabinol, and includes two G-protein-coupled receptors (GPCRs; the cannabinoid CB1 and CB2 receptors), their endogenous ligands (the endocannabinoids, the best studied of which are anandamide and 2-arachidonoylglycerol (2-AG)), and the proteins that regulate the levels and activity of these receptors and ligands. However, other minor lipid metabolites different from, but chemically similar to, anandamide and 2-AG have also been suggested to act as endocannabinoids. Thus, unlike most other GPCRs, cannabinoid receptors appear to have more than one endogenous agonist, and it has been often wondered what could be the physiological meaning of this peculiarity. In 1999, it was proposed that anandamide might also activate other targets, and in particular the transient receptor potential of vanilloid type-1 (TRPV1) channels. Over the last decade, this interaction has been shown to occur both in peripheral tissues and brain, during both physiological and pathological conditions. TRPV1 channels can be activated also by another less abundant endocannabinoid, N-arachidonoyldopamine, but not by 2-AG, and have been proposed by some authors to act as ionotropic endocannabinoid receptors. This article will discuss the latest discoveries on this subject, and discuss, among others, how anandamide and 2-AG differential actions at TRPV1 and cannabinoid receptors contribute to making this signalling system a versatile tool available to organisms to fine-tune homeostasis.
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Affiliation(s)
- Vincenzo Di Marzo
- Endocannabinoid Research Group, Istituto Chimica Biomolecolare, CNR, Via Campi Flegrei 34, Comprensorio Olivetti, 80078 Pozzuoli, NA, Italy.
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107
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Bilkei-Gorzo A. The endocannabinoid system in normal and pathological brain ageing. Philos Trans R Soc Lond B Biol Sci 2013; 367:3326-41. [PMID: 23108550 DOI: 10.1098/rstb.2011.0388] [Citation(s) in RCA: 92] [Impact Index Per Article: 8.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/01/2023] Open
Abstract
The role of endocannabinoids as inhibitory retrograde transmitters is now widely known and intensively studied. However, endocannabinoids also influence neuronal activity by exerting neuroprotective effects and regulating glial responses. This review centres around this less-studied area, focusing on the cellular and molecular mechanisms underlying the protective effect of the cannabinoid system in brain ageing. The progression of ageing is largely determined by the balance between detrimental, pro-ageing, largely stochastic processes, and the activity of the homeostatic defence system. Experimental evidence suggests that the cannabinoid system is part of the latter system. Cannabinoids as regulators of mitochondrial activity, as anti-oxidants and as modulators of clearance processes protect neurons on the molecular level. On the cellular level, the cannabinoid system regulates the expression of brain-derived neurotrophic factor and neurogenesis. Neuroinflammatory processes contributing to the progression of normal brain ageing and to the pathogenesis of neurodegenerative diseases are suppressed by cannabinoids, suggesting that they may also influence the ageing process on the system level. In good agreement with the hypothesized beneficial role of cannabinoid system activity against brain ageing, it was shown that animals lacking CB1 receptors show early onset of learning deficits associated with age-related histological and molecular changes. In preclinical models of neurodegenerative disorders, cannabinoids show beneficial effects, but the clinical evidence regarding their efficacy as therapeutic tools is either inconclusive or still missing.
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108
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Castillo PE, Younts TJ, Chávez AE, Hashimotodani Y. Endocannabinoid signaling and synaptic function. Neuron 2012; 76:70-81. [PMID: 23040807 DOI: 10.1016/j.neuron.2012.09.020] [Citation(s) in RCA: 709] [Impact Index Per Article: 59.1] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 09/14/2012] [Indexed: 12/17/2022]
Abstract
Endocannabinoids are key modulators of synaptic function. By activating cannabinoid receptors expressed in the central nervous system, these lipid messengers can regulate several neural functions and behaviors. As experimental tools advance, the repertoire of known endocannabinoid-mediated effects at the synapse, and their underlying mechanism, continues to expand. Retrograde signaling is the principal mode by which endocannabinoids mediate short- and long-term forms of plasticity at both excitatory and inhibitory synapses. However, growing evidence suggests that endocannabinoids can also signal in a nonretrograde manner. In addition to mediating synaptic plasticity, the endocannabinoid system is itself subject to plastic changes. Multiple points of interaction with other neuromodulatory and signaling systems have now been identified. In this Review, we focus on new advances in synaptic endocannabinoid signaling in the mammalian brain. The emerging picture not only reinforces endocannabinoids as potent regulators of synaptic function but also reveals that endocannabinoid signaling is mechanistically more complex and diverse than originally thought.
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Affiliation(s)
- Pablo E Castillo
- Dominick P. Purpura Department of Neuroscience, Albert Einstein College of Medicine, Bronx, NY 10461, USA.
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109
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Saito A, Ballinger MDL, Pletnikov MV, Wong DF, Kamiya A. Endocannabinoid system: potential novel targets for treatment of schizophrenia. Neurobiol Dis 2012; 53:10-7. [PMID: 23220619 DOI: 10.1016/j.nbd.2012.11.020] [Citation(s) in RCA: 28] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/04/2012] [Revised: 11/23/2012] [Accepted: 11/28/2012] [Indexed: 10/27/2022] Open
Abstract
Accumulating epidemiological evidences suggest that cannabis use during adolescence is a potential environmental risk for the development of psychosis, including schizophrenia. Consistently, clinical and preclinical studies, using pharmacological approaches and genetically engineered animals to target endocannabinoid signaling, reveal the multiple varieties of endocannabinoid system-mediated human and animal behaviors, including cognition and emotion. Recently, there has been substantial progress in understanding the molecular mechanisms of the endocannabinoid system for synaptic communications in the central nervous system. Furthermore, the impact of endocannabinoid signaling on diverse cellular processes during brain development has emerged. Thus, although schizophrenia has etiological complexities, including genetic heterogeneities and multiple environmental factors, it now becomes crucial to explore molecular pathways of convergence of genetic risk factors and endocannabinoid signaling, which may provide us with clues to find novel targets for therapeutic intervention. In this review, epidemiological, clinical, and pathological evidences on the role of the endocannabinoid system in the pathophysiologies of schizophrenia will be presented. We will also make a brief overview of the recent progress in understanding molecular mechanisms of the endocannabinoid system for brain development and function, with particular focus on cannabinoid receptor type 1 (CB1R)-mediated cascade, the most well-characterized cannabinoid receptor. Lastly, we will discuss the potential of the endocannabinoid system in finding novel therapeutic targets for prevention and treatment of schizophrenia.
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Affiliation(s)
- Atsushi Saito
- Department of Psychiatry and Behavioral Sciences, Johns Hopkins University School of Medicine, Baltimore, MD21287, USA
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110
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Reisenberg M, Singh PK, Williams G, Doherty P. The diacylglycerol lipases: structure, regulation and roles in and beyond endocannabinoid signalling. Philos Trans R Soc Lond B Biol Sci 2012; 367:3264-75. [PMID: 23108545 PMCID: PMC3481529 DOI: 10.1098/rstb.2011.0387] [Citation(s) in RCA: 100] [Impact Index Per Article: 8.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/14/2022] Open
Abstract
The diacylglycerol lipases (DAGLs) hydrolyse diacylglycerol to generate 2-arachidonoylglycerol (2-AG), the most abundant ligand for the CB(1) and CB(2) cannabinoid receptors in the body. DAGL-dependent endocannabinoid signalling regulates axonal growth and guidance during development, and is required for the generation and migration of new neurons in the adult brain. At developed synapses, 2-AG released from postsynaptic terminals acts back on presynaptic CB(1) receptors to inhibit the secretion of both excitatory and inhibitory neurotransmitters, with this DAGL-dependent synaptic plasticity operating throughout the nervous system. Importantly, the DAGLs have functions that do not involve cannabinoid receptors. For example, 2-AG is the precursor of arachidonic acid in a pathway that maintains the level of this essential lipid in the brain and other organs. This pathway also drives the cyclooxygenase-dependent generation of inflammatory prostaglandins in the brain, which has recently been implicated in the degeneration of dopaminergic neurons in Parkinson's disease. Remarkably, we still know very little about the mechanisms that regulate DAGL activity-however, key insights can be gleaned by homology modelling against other α/β hydrolases and from a detailed examination of published proteomic studies and other databases. These identify a regulatory loop with a highly conserved signature motif, as well as phosphorylation and palmitoylation as post-translational mechanisms likely to regulate function.
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Affiliation(s)
| | | | - Gareth Williams
- Wolfson Centre for Age-Related Diseases, King's College London, SE1 9RT, UK
| | - Patrick Doherty
- Wolfson Centre for Age-Related Diseases, King's College London, SE1 9RT, UK
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111
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Hsu KL, Tsuboi K, Adibekian A, Pugh H, Masuda K, Cravatt BF. DAGLβ inhibition perturbs a lipid network involved in macrophage inflammatory responses. Nat Chem Biol 2012; 8:999-1007. [PMID: 23103940 PMCID: PMC3513945 DOI: 10.1038/nchembio.1105] [Citation(s) in RCA: 169] [Impact Index Per Article: 14.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/30/2012] [Accepted: 09/24/2012] [Indexed: 11/09/2022]
Abstract
The endocannabinoid 2-arachidonoylglycerol (2-AG) is biosynthesized by diacylglycerol lipases DAGLα and DAGLβ. Chemical probes to perturb DAGLs are needed to characterize endocannabinoid function in biological processes. Here we report a series of 1,2,3-triazole urea inhibitors, along with paired negative-control and activity-based probes, for the functional analysis of DAGLβ in living systems. Optimized inhibitors showed high selectivity for DAGLβ over other serine hydrolases, including DAGLα (∼60-fold selectivity), and the limited off-targets, such as ABHD6, were also inhibited by the negative-control probe. Using these agents and Daglb(-/-) mice, we show that DAGLβ inactivation lowers 2-AG, as well as arachidonic acid and eicosanoids, in mouse peritoneal macrophages in a manner that is distinct and complementary to disruption of cytosolic phospholipase-A2. We observed a corresponding reduction in lipopolysaccharide-induced tumor necrosis factor-α release. These findings indicate that DAGLβ is a key metabolic hub within a lipid network that regulates proinflammatory responses in macrophages.
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Affiliation(s)
- Ku-Lung Hsu
- The Skaggs Institute for Chemical Biology, The Scripps Research Institute, La Jolla, California, USA
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112
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Schmidt W, Schäfer F, Striggow V, Fröhlich K, Striggow F. Cannabinoid receptor subtypes 1 and 2 mediate long-lasting neuroprotection and improve motor behavior deficits after transient focal cerebral ischemia. Neuroscience 2012; 227:313-26. [PMID: 23069763 DOI: 10.1016/j.neuroscience.2012.09.080] [Citation(s) in RCA: 32] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/21/2012] [Revised: 09/24/2012] [Accepted: 09/28/2012] [Indexed: 11/18/2022]
Abstract
The endocannabinoid system is crucially involved in the regulation of brain activity and inflammation. We have investigated the localization of cannabinoid CB1 and CB2 receptors in adult rat brains before and after focal cerebral ischemia due to endothelin-induced transient occlusion of the middle cerebral artery (eMCAO). Using immunohistochemistry, both receptor subtypes were identified in cortical neurons. After eMCAO, neuronal cell death was accompanied by reduced neuronal CB1 and CB2 receptor-linked immunofluorescence. In parallel, CB1 receptor was found in activated microglia/macrophages 3 days post eMCAO and in astroglia cells at days 3 and 7. CB2 receptor labeling was identified in activated microglia/macrophages or astroglia 3 and 7d ays post ischemia, respectively. In addition, immune competent CD45-positive cells were characterized by pronounced CB2 receptor staining 3 and 7 days post eMCAO. KN38-72717, a potent and selective CB1 and CB2 receptor agonist, revealed a significant, dose-dependent and long-lasting reduction of cortical lesion sizes due to eMCAO, when applied consecutively before, during and after eMCAO. In addition, severe motor deficits of animals suffering from eMCAO were significantly improved by KN38-7271. KN38-7271 remained effective, even if its application was delayed up to 6h post eMCAO. Finally, we show that the endocannabinoid system assembles a comprehensive machinery to defend the brain against the devastating consequences of cerebral ischemia. In summary, this study underlines the therapeutic potential of CB1 and/or CB2 receptor agonists against neurodegenerative diseases or injuries involving acute or chronic imbalances of cerebral blood flow and energy consumption.
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Affiliation(s)
- W Schmidt
- KeyNeurotek Pharmaceuticals AG, ZENIT Technology Park, Leipziger Straße 44, D-39120 Magdeburg, Germany
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113
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Lee TTY, Hill MN, Hillard CJ, Gorzalka BB. Temporal changes in N-acylethanolamine content and metabolism throughout the peri-adolescent period. Synapse 2012; 67:4-10. [PMID: 22987804 DOI: 10.1002/syn.21609] [Citation(s) in RCA: 54] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/16/2012] [Accepted: 09/06/2012] [Indexed: 12/31/2022]
Abstract
Fatty acid amide hydrolase (FAAH) regulates tissue concentrations of N-acylethanolamines (NAEs), including the endocannabinoid, N-arachidonylethanolamide (anandamide, AEA). FAAH activity and NAEs are widely distributed throughout the brain and FAAH activity regulates an array of processes including emotion, cognition, inflammation, and feeding. However, there is relatively little research describing how this system develops throughout adolescence, particularly within limbic circuits regulating stress and reward processing. Thus, this study characterized temporal changes in NAE content (AEA, oleoylethanolamine [OEA], and palmitoylethanolamide [PEA]) and FAAH activity across the peri-adolescent period, in four corticolimbic structures (amygdala, hippocampus, prefrontal cortex, and hypothalamus). Brain tissue of male Sprague-Dawley rats was collected on postnatal days (PND) 25, 35, 45, and 70, representing pre-adolescence, early- to mid-adolescence, late adolescence, and adulthood, respectively. Tissue was analyzed for AEA, OEA, and PEA content as well as FAAH activity at each time point. AEA, OEA, and PEA exhibited a similar temporal pattern in all four brain regions. NAE concentrations were lowest at PND 25 and highest at PND 35. NAE concentrations decreased between PNDs 35 and 45 and increased between PNDs 45 and 70. FAAH activity mirrored the pattern of NAE content in which it decreased between PNDs 25 and 35, increased between PNDs 35 and 45, and decreased between PNDs 45 and 70. These age-dependent patterns of NAE content and FAAH activity demonstrate temporal specificity to the development of this system and could contribute to alterations in stress sensitivity, emotionality, and executive function which also fluctuate during this developmental period.
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Affiliation(s)
- Tiffany T-Y Lee
- Department of Psychology, University of British Columbia, Vancouver, British Columbia, Canada V6T 1Z4
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114
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Butti E, Bacigaluppi M, Rossi S, Cambiaghi M, Bari M, Cebrian Silla A, Brambilla E, Musella A, De Ceglia R, Teneud L, De Chiara V, D'Adamo P, Garcia-Verdugo JM, Comi G, Muzio L, Quattrini A, Leocani L, Maccarrone M, Centonze D, Martino G. Subventricular zone neural progenitors protect striatal neurons from glutamatergic excitotoxicity. ACTA ACUST UNITED AC 2012; 135:3320-35. [PMID: 23008234 DOI: 10.1093/brain/aws194] [Citation(s) in RCA: 56] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/22/2022]
Abstract
The functional significance of adult neural stem and progenitor cells in hippocampal-dependent learning and memory has been well documented. Although adult neural stem and progenitor cells in the subventricular zone are known to migrate to, maintain and reorganize the olfactory bulb, it is less clear whether they are functionally required for other processes. Using a conditional transgenic mouse model, selective ablation of adult neural stem and progenitor cells in the subventricular zone induced a dramatic increase in morbidity and mortality of central nervous system disorders characterized by excitotoxicity-induced cell death accompanied by reactive inflammation, such as 4-aminopyridine-induced epilepsy and ischaemic stroke. To test the role of subventricular zone adult neural stem and progenitor cells in protecting central nervous system tissue from glutamatergic excitotoxicity, neurophysiological recordings of spontaneous excitatory postsynaptic currents from single medium spiny striatal neurons were measured on acute brain slices. Indeed, lipopolysaccharide-stimulated, but not unstimulated, subventricular zone adult neural stem and progenitor cells reverted the increased frequency and duration of spontaneous excitatory postsynaptic currents by secreting the endocannabinod arachidonoyl ethanolamide, a molecule that regulates glutamatergic tone through type 1 cannabinoid receptor (CB(1)) binding. In vivo restoration of cannabinoid levels, either by administration of the type 1 cannabinoid receptor agonist HU210 or the inhibitor of the principal catabolic enzyme fatty acid amide hydrolase, URB597, completely reverted the increased morbidity and mortality of adult neural stem and progenitor cell-ablated mice suffering from epilepsy and ischaemic stroke. Our results provide the first evidence that adult neural stem and progenitor cells located within the subventricular zone exert an 'innate' homeostatic regulatory role by protecting striatal neurons from glutamate-mediated excitotoxicity.
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Affiliation(s)
- Erica Butti
- Neuroimmunology Unit, INSPE, Division of Neuroscience, San Raffaele Scientific Institute Via Olgettina 58, 20132 Milan, Italy
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115
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Luchicchi A, Pistis M. Anandamide and 2-arachidonoylglycerol: Pharmacological Properties, Functional Features, and Emerging Specificities of the Two Major Endocannabinoids. Mol Neurobiol 2012; 46:374-92. [DOI: 10.1007/s12035-012-8299-0] [Citation(s) in RCA: 65] [Impact Index Per Article: 5.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/21/2012] [Accepted: 07/03/2012] [Indexed: 12/18/2022]
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116
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Callén L, Moreno E, Barroso-Chinea P, Moreno-Delgado D, Cortés A, Mallol J, Casadó V, Lanciego JL, Franco R, Lluis C, Canela EI, McCormick PJ. Cannabinoid receptors CB1 and CB2 form functional heteromers in brain. J Biol Chem 2012; 287:20851-65. [PMID: 22532560 DOI: 10.1074/jbc.m111.335273] [Citation(s) in RCA: 164] [Impact Index Per Article: 13.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/13/2023] Open
Abstract
Exploring the role of cannabinoid CB(2) receptors in the brain, we present evidence of CB(2) receptor molecular and functional interaction with cannabinoid CB(1) receptors. Using biophysical and biochemical approaches, we discovered that CB(2) receptors can form heteromers with CB(1) receptors in transfected neuronal cells and in rat brain pineal gland, nucleus accumbens, and globus pallidus. Within CB(1)-CB(2) receptor heteromers expressed in a neuronal cell model, agonist co-activation of CB(1) and CB(2) receptors resulted in a negative cross-talk in Akt phosphorylation and neurite outgrowth. Moreover, one specific characteristic of CB(1)-CB(2) receptor heteromers consists of both the ability of CB(1) receptor antagonists to block the effect of CB(2) receptor agonists and, conversely, the ability of CB(2) receptor antagonists to block the effect of CB(1) receptor agonists, showing a bidirectional cross-antagonism phenomenon. Taken together, these data illuminate the mechanism by which CB(2) receptors can negatively modulate CB(1) receptor function.
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Affiliation(s)
- Lucía Callén
- Department of Biochemistry and Molecular Biology, Faculty of Biology, University of Barcelona, 08028 Barcelona, Spain
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117
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Kiritoshi T, Sun H, Ren W, Stauffer SR, Lindsley CW, Conn PJ, Neugebauer V. Modulation of pyramidal cell output in the medial prefrontal cortex by mGluR5 interacting with CB1. Neuropharmacology 2012; 66:170-8. [PMID: 22521499 DOI: 10.1016/j.neuropharm.2012.03.024] [Citation(s) in RCA: 34] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/23/2011] [Revised: 03/27/2012] [Accepted: 03/29/2012] [Indexed: 01/20/2023]
Abstract
The medial prefrontal cortex (mPFC) serves executive cognitive functions such as decision-making that are impaired in neuropsychiatric disorders and pain. We showed previously that amygdala-driven abnormal inhibition and decreased output of mPFC pyramidal cells contribute to pain-related impaired decision-making (Ji et al., 2010). Therefore, modulating pyramidal output is desirable therapeutic goal. Targeting metabotropic glutamate receptor subtype mGluR5 has emerged as a cognitive-enhancing strategy in neuropsychiatric disorders, but synaptic and cellular actions of mGluR5 in the mPFC remain to be determined. The present study determined synaptic and cellular actions of mGluR5 to test the hypothesis that increasing mGluR5 function can enhance pyramidal cell output. Whole-cell voltage- and current-clamp recordings were made from visually identified pyramidal neurons in layer V of the mPFC in rat brain slices. Both the prototypical mGluR5 agonist CHPG and a positive allosteric modulator (PAM) for mGluR5 (VU0360172) increased synaptically evoked spiking (E-S coupling) in mPFC pyramidal cells. The facilitatory effects of CHPG and VU0360172 were inhibited by an mGluR5 antagonist (MTEP). CHPG, but not VU0360172, increased neuronal excitability (frequency-current [F-I] function). VU0360172, but not CHPG, increased evoked excitatory synaptic currents (EPSCs) and amplitude, but not frequency, of miniature EPSCs, indicating a postsynaptic action. VU0360172, but not CHPG, decreased evoked inhibitory synaptic currents (IPSCs) through an action that involved cannabinoid receptor CB1, because a CB1 receptor antagonist (AM281) blocked the inhibitory effect of VU0360172 on synaptic inhibition. VU0360172 also increased and prolonged CB1-mediated depolarization-induced suppression of synaptic inhibition (DSI). Activation of CB1 with ACEA decreased inhibitory transmission through a presynaptic mechanism. The results show that increasing mGluR5 function enhances mPFC output. This effect can be accomplished by increasing excitability with an orthosteric agonist (CHPG) or by increasing excitatory synaptic drive and CB1-mediated presynaptic suppression of synaptic inhibition ("dis-inhibition") with a PAM (VU0360172). Therefore, mGluR5 may be a useful target in conditions of impaired mPFC output. This article is part of a Special Issue entitled 'Metabotropic Glutamate Receptors'.
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Affiliation(s)
- Takaki Kiritoshi
- Department of Neuroscience and Cell Biology, The University of Texas Medical Branch, 301 University Blvd. Galveston, TX 77555-1069, USA.
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118
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Oudin MJ, Hobbs C, Doherty P. DAGL-dependent endocannabinoid signalling: roles in axonal pathfinding, synaptic plasticity and adult neurogenesis. Eur J Neurosci 2012; 34:1634-46. [PMID: 22103420 DOI: 10.1111/j.1460-9568.2011.07831.x] [Citation(s) in RCA: 64] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/02/2023]
Abstract
Until recently, endocannabinoid (eCB) signalling was largely studied in the context of synaptic plasticity in the postnatal brain in the absence of detailed knowledge of the nature of the enzyme(s) responsible for the synthesis of the eCBs. However, the identification of two diacylglycerol lipases (DAGLα and DAGLβ) responsible for the synthesis of 2-arachidonoylglycerol (2-AG) has increased the understanding of where this eCB is synthesised in relationship to the expression of cannabinoid receptor (CB)1 and CB2. Furthermore, the generation of knockout animals for each enzyme has allowed for the direct testing of their importance for established and emerging eCB functions. Based on this, we now know that DAGLα is enriched in dendritic spines that appose CB1-positive synaptic terminals, and that 2-AG functions as a retrograde signal controlling synaptic strength throughout the nervous system. Consequently, we have built on the principle that expression of eCB components dictates function to identify additional physiological functions of this signalling cassette. A number of studies have now provided support for DAGL-dependent eCB signalling playing important roles in brain development and in cellular plasticity in the adult nervous system. In this article, we will review evidence based on the localisation of the enzymes, as well as from genetic and pharmacological studies, that show DAGL-dependent eCB signalling to play an important role in axonal growth and guidance during development, in retrograde synaptic signalling at mature synapses, and in the control of adult neurogenesis in the hippocampus and subventricular zone.
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Affiliation(s)
- Madeleine J Oudin
- Wolfson Centre for Age-Related Diseases, King's College London, London, UK
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119
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Excitability of prefrontal cortical pyramidal neurons is modulated by activation of intracellular type-2 cannabinoid receptors. Proc Natl Acad Sci U S A 2012; 109:3534-9. [PMID: 22331871 DOI: 10.1073/pnas.1118167109] [Citation(s) in RCA: 137] [Impact Index Per Article: 11.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/18/2022] Open
Abstract
The endocannabinoid (eCB) system is widely expressed throughout the central nervous system (CNS) and the functionality of type-1 cannabinoid receptors in neurons is well documented. In contrast, there is little knowledge about type-2 cannabinoid receptors (CB(2)Rs) in the CNS. Here, we show that CB(2)Rs are located intracellularly in layer II/III pyramidal cells of the rodent medial prefrontal cortex (mPFC) and that their activation results in IP(3)R-dependent opening of Ca(2+)-activated Cl(-) channels. To investigate the functional role of CB(2)R activation, we induced neuronal firing and observed a CB(2)R-mediated reduction in firing frequency. The description of this unique CB(2)R-mediated signaling pathway, controlling neuronal excitability, broadens our knowledge of the influence of the eCB system on brain function.
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120
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Alger BE. Endocannabinoids at the synapse a decade after the dies mirabilis (29 March 2001): what we still do not know. J Physiol 2012; 590:2203-12. [PMID: 22289914 DOI: 10.1113/jphysiol.2011.220855] [Citation(s) in RCA: 66] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/23/2023] Open
Abstract
Endogenous cannabinoids (endocannabinoids, eCBs) are ubiquitous regulators of synaptic transmission in the brain, mediating numerous forms of short- and long-term plasticity, and having strong influences on synapse formation and neurogenesis. Their roles as retrograde messengers that suppress both excitatory and inhibitory transmission are well-established. Yet, despite intensive investigation, many basic aspects of the eCB system are not understood. This brief review highlights recent advances, problems that remain unresolved, and avenues for future exploration. While 2-arachidonoylglycerol (2-AG) is probably the major eCB for intercellular CB1R-dependent signalling, anandamide (AEA) has come to the forefront in several novel contexts, both as a dual endovanilloid/endocannabinoid that regulates synaptic transmission acutely and as the source of a steady eCB tone in hippocampus. Complexities in the cellular processing of 2-AG are receiving renewed attention, as they are increasingly recognized as major determinants of how 2-AG affects cells. Long-standing fundamental issues such as the synthesis pathway for AEA and the molecular mechanism(s) underlying cellular uptake and release of eCBs remain problematical.
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Affiliation(s)
- Bradley E Alger
- Department of Physiology, University of Maryland School of Medicine, 655 W. Baltimore Street, Rm 5-025, Baltimore, MD 21201, USA.
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121
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Basu S, Dittel BN. Unraveling the complexities of cannabinoid receptor 2 (CB2) immune regulation in health and disease. Immunol Res 2012; 51:26-38. [PMID: 21626285 DOI: 10.1007/s12026-011-8210-5] [Citation(s) in RCA: 105] [Impact Index Per Article: 8.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/15/2022]
Abstract
It has become clear that the endocannabinoid system is a potent regulator of immune responses, with the cannabinoid receptor 2 (CB2) as the key component due to its high expression by all immune subtypes. CB2 has been shown to regulate immunity by a number of mechanisms including development, migration, proliferation, and effector functions. In addition, CB2 has been shown to modulate the function of all immune cell types examined to date. CB2 is a G(i)-protein-coupled receptor and thus exhibits a complex pharmacology allowing both stimulatory and inhibitory signaling that depends on receptor expression levels, ligand concentration, and cell lineage specificities. Here, we discuss both in vitro and in vivo experimental evidence that CB2 is a potent regulator of immune responses making it a prime target for the treatment of inflammatory diseases.
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Affiliation(s)
- Sreemanti Basu
- Blood Research Institute, Blood Center of Wisconsin, Milwaukee, WI, USA
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122
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Bojnik E, Turunç E, Armağan G, Kanıt L, Benyhe S, Yalçın A, Borsodi A. Changes in the cannabinoid (CB1) receptor expression level and G-protein activation in kainic acid induced seizures. Epilepsy Res 2011; 99:64-8. [PMID: 22079489 DOI: 10.1016/j.eplepsyres.2011.10.020] [Citation(s) in RCA: 26] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/20/2011] [Revised: 10/09/2011] [Accepted: 10/15/2011] [Indexed: 11/19/2022]
Abstract
It has been known for centuries that exogenous cannabinoids, such as tetrahydrocannabinol have anticonvulsant activity. Recent studies have advanced our understanding of the endogenous cannabinoid system and renewed the interest in cannabinoids as a potential treatment for epilepsy. The endogenous cannabinoid system is rapidly activated after seizure activity but still little is known about the molecular mechanisms underlying the role of the cannabinoid system in epilepsy. In this study epileptiform activity was induced by kainic acid (KA) and effects of the CB1 receptor agonists N-(2-Chloroethyl)-5Z,8Z,11Z,14Z-eicosatetraenamide (ACEA) on G-protein signaling using the agonist-stimulated [(35)S]GTPγS binding assay were evaluated. Control and KA treated rat hippocampus and cortex membranes were used. Our results showed that the ACEA displayed a high potency and efficacy in stimulating the G-proteins and when compared to the control animals, significant enhancements were observed in tissues from the KA treated animals. Potency and efficacy values were in particular increased in the hippocampus tissues. Furthermore, gene expression levels of the cannabinoid receptor 1 (CB1) receptor and cannabinoid receptor interacting protein 1 (CRIP1) were measured by RT-PCR, where both CB1 and CRIP1 expressions were found to be elevated in the KA treated animals.
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Affiliation(s)
- Engin Bojnik
- Institute of Biochemistry, Biological Research Centre, Hungarian Academy of Sciences, Temesvari krt 62, 6726 Szeged, Hungary.
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123
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Abstract
Inhibitory neurons in the thalamic reticular nucleus (TRN) play a critical role in controlling information transfer between thalamus and neocortex. GABAergic synapses formed by TRN neurons contact both thalamic relay cells and neurons within TRN. These two types of synapses are thought to have distinct roles for the generation of thalamic network activity, but their selective regulation is poorly understood. In many areas throughout the brain, retrograde signaling mediated by endocannabinoids acts to dynamically regulate synaptic strength over both short and long time scales. However, retrograde signaling has never been demonstrated in the thalamus. Here, we show that depolarization-induced suppression of inhibition (DSI) is prominent at inhibitory synapses interconnecting TRN neurons. DSI is completely abolished in the presence of a cannabinoid receptor 1 (CB1R) antagonist and in mice lacking CB1Rs. DSI is prevented by DAG lipase inhibitors and prolonged by blocking the 2-arachidonoylglycerol (2-AG) degradation enzyme monoacylglycerol lipase, indicating that it is mediated by the release of 2-AG from TRN neurons. By contrast, DSI is not observed at TRN synapses targeting thalamic relay neurons. A combination of pharmacological and immunohistochemical data indicate that the differences in endocannabinoid signaling at the two synapses are mediated by a synapse-specific targeting of CB1Rs, as well as differences in endocannabinoid release between the two target neurons. Together, our results show that endocannabinoids control transmitter release at specific thalamic synapses, and could dynamically regulate sensory information processing and thalamus-mediated synchronous oscillations.
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124
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Yoshino H, Miyamae T, Hansen G, Zambrowicz B, Flynn M, Pedicord D, Blat Y, Westphal RS, Zaczek R, Lewis DA, Gonzalez-Burgos G. Postsynaptic diacylglycerol lipase mediates retrograde endocannabinoid suppression of inhibition in mouse prefrontal cortex. J Physiol 2011; 589:4857-84. [PMID: 21807615 DOI: 10.1113/jphysiol.2011.212225] [Citation(s) in RCA: 77] [Impact Index Per Article: 5.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/21/2023] Open
Abstract
Depolarization-induced suppression of inhibition (DSI) is a prevailing form of endocannabinoid signalling. However, several discrepancies have arisen regarding the roles played by the two major brain endocannabinoids, 2-arachidonoylglycerol (2-AG) and anandamide, in mediating DSI. Here we studied endocannabinoid signalling in the prefrontal cortex (PFC), where several components of the endocannabinoid system have been identified, but endocannabinoid signalling remains largely unexplored. In voltage clamp recordings from mouse PFC pyramidal neurons, depolarizing steps significantly suppressed IPSCs induced by application of the cholinergic agonist carbachol. DSI in PFC neurons was abolished by extra- or intracellular application of tetrahydrolipstatin (THL), an inhibitor of the 2-AG synthesis enzyme diacylglycerol lipase (DAGL). Moreover, DSI was enhanced by inhibiting 2-AG degradation, but was unaffected by inhibiting anandamide degradation. THL, however, may affect other enzymes of lipid metabolism and does not selectively target the α (DAGLα) or β (DAGLβ) isoforms of DAGL. Therefore, we studied DSI in the PFC of DAGLα(-/-) and DAGLβ(-/-) mice generated via insertional mutagenesis by gene-trapping with retroviral vectors. Gene trapping strongly reduced DAGLα or DAGLβ mRNA levels in a locus-specific manner. In DAGLα(-/-) mice cortical levels of 2-AG were significantly decreased and DSI was completely abolished, whereas DAGLβ deficiency did not alter cortical 2-AG levels or DSI. Importantly, cortical levels of anandamide were not significantly affected in DAGLα(-/-) or DAGLβ(-/-) mice. The chronic decrease of 2-AG levels in DAGLα(-/-) mice did not globally alter inhibitory transmission or the response of cannabinoid-sensitive synapses to cannabinoid receptor stimulation, although it altered some intrinsic membrane properties. Finally, we found that repetitive action potential firing of PFC pyramidal neurons suppressed synaptic inhibition in a DAGLα-dependent manner. These results show that DSI is a prominent form of endocannabinoid signalling in PFC circuits. Moreover, the close agreement between our pharmacological and genetic studies indicates that 2-AG synthesized by postsynaptic DAGLα mediates DSI in PFC neurons.
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Affiliation(s)
- Hiroki Yoshino
- Translational Neuroscience Program, Department of Psychiatry, University of Pittsburgh, Pittsburgh, PA 15261, USA
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125
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Wu CS, Jew CP, Lu HC. Lasting impacts of prenatal cannabis exposure and the role of endogenous cannabinoids in the developing brain. FUTURE NEUROLOGY 2011; 6:459-480. [PMID: 22229018 PMCID: PMC3252200 DOI: 10.2217/fnl.11.27] [Citation(s) in RCA: 101] [Impact Index Per Article: 7.8] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/22/2022]
Abstract
Cannabis is the most commonly used illicit substance among pregnant women. Human epidemiological and animal studies have found that prenatal cannabis exposure influences brain development and can have long-lasting impacts on cognitive functions. Exploration of the therapeutic potential of cannabis-based medicines and synthetic cannabinoid compounds has given us much insight into the physiological roles of endogenous ligands (endocannabinoids) and their receptors. In this article, we examine human longitudinal cohort studies that document the long-term influence of prenatal exposure to cannabis, followed by an overview of the molecular composition of the endocannabinoid system and the temporal and spatial changes in their expression during brain development. How endocannabinoid signaling modulates fundamental developmental processes such as cell proliferation, neurogenesis, migration and axonal pathfinding are also summarized.
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Affiliation(s)
- Chia-Shan Wu
- The Cain Foundation Laboratories, Jan & Dan Duncan Neurological Research Institute at Texas Children's Hospital, 1250 Moursund St Suite 1225, Houston, TX 77030, USA
| | - Christopher P Jew
- The Cain Foundation Laboratories, Jan & Dan Duncan Neurological Research Institute at Texas Children's Hospital, 1250 Moursund St Suite 1225, Houston, TX 77030, USA
- Program in Developmental Biology, Baylor College of Medicine, Houston, TX 77030, USA
| | - Hui-Chen Lu
- The Cain Foundation Laboratories, Jan & Dan Duncan Neurological Research Institute at Texas Children's Hospital, 1250 Moursund St Suite 1225, Houston, TX 77030, USA
- Program in Developmental Biology, Baylor College of Medicine, Houston, TX 77030, USA
- Department of Pediatrics, Baylor College of Medicine, Houston, TX 77030, USA
- Department of Neuroscience, Baylor College of Medicine, Houston, TX 77030, USA
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126
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Alger BE, Kim J. Supply and demand for endocannabinoids. Trends Neurosci 2011; 34:304-15. [PMID: 21507493 DOI: 10.1016/j.tins.2011.03.003] [Citation(s) in RCA: 189] [Impact Index Per Article: 14.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/03/2010] [Revised: 02/21/2011] [Accepted: 03/11/2011] [Indexed: 10/18/2022]
Abstract
The endocannabinoid system consists of G-protein-coupled cannabinoid receptors that can be activated by cannabis-derived drugs and small lipids termed endocannabinoids (eCBs) plus associated biochemical machinery (precursors, synthetic and degradative enzymes, transporters). The eCB system in the brain primarily influences neuronal synaptic communication, and affects biological functions - including eating, anxiety, learning and memory, growth and development - via an array of actions throughout the nervous system. Although many aspects of synaptic regulation by eCBs are becoming clear, details of the subcellular organization and regulation of the eCB system are less well understood. This review focuses on recent investigations that illuminate fundamental issues of eCB storage, release, and functional roles.
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Affiliation(s)
- Bradley E Alger
- Department of Physiology, University of Maryland School of Medicine, 655 West Baltimore Street, Baltimore, MD 21201, USA.
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