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Kouchaeknejad A, Van Der Walt G, De Donato MH, Puighermanal E. Imaging and Genetic Tools for the Investigation of the Endocannabinoid System in the CNS. Int J Mol Sci 2023; 24:15829. [PMID: 37958825 PMCID: PMC10648052 DOI: 10.3390/ijms242115829] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/15/2023] [Revised: 10/26/2023] [Accepted: 10/27/2023] [Indexed: 11/15/2023] Open
Abstract
As central nervous system (CNS)-related disorders present an increasing cause of global morbidity, mortality, and high pressure on our healthcare system, there is an urgent need for new insights and treatment options. The endocannabinoid system (ECS) is a critical network of endogenous compounds, receptors, and enzymes that contribute to CNS development and regulation. Given its multifaceted involvement in neurobiology and its significance in various CNS disorders, the ECS as a whole is considered a promising therapeutic target. Despite significant advances in our understanding of the ECS's role in the CNS, its complex architecture and extensive crosstalk with other biological systems present challenges for research and clinical advancements. To bridge these knowledge gaps and unlock the full therapeutic potential of ECS interventions in CNS-related disorders, a plethora of molecular-genetic tools have been developed in recent years. Here, we review some of the most impactful tools for investigating the neurological aspects of the ECS. We first provide a brief introduction to the ECS components, including cannabinoid receptors, endocannabinoids, and metabolic enzymes, emphasizing their complexity. This is followed by an exploration of cutting-edge imaging tools and genetic models aimed at elucidating the roles of these principal ECS components. Special emphasis is placed on their relevance in the context of CNS and its associated disorders.
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Affiliation(s)
| | | | | | - Emma Puighermanal
- Neuroscience Institute, Autonomous University of Barcelona, 08193 Bellaterra, Spain; (A.K.); (G.V.D.W.); (M.H.D.D.)
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O'Brien LD, Smith TL, Donvito G, Cravatt BF, Newton J, Spiegel S, Reeves TM, Phillips LL, Lichtman AH. Diacylglycerol Lipase-β Knockout Mice Display a Sex-Dependent Attenuation of Traumatic Brain Injury-Induced Mortality with No Impact on Memory or Other Functional Consequences. Cannabis Cannabinoid Res 2021; 6:508-521. [PMID: 34142866 DOI: 10.1089/can.2020.0175] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/21/2022] Open
Abstract
Background: The endogenous cannabinoid system modulates inflammatory signaling in a variety of pathological states, including traumatic brain injury (TBI). The selective expression of diacylglycerol lipase-β (DAGL-β), the 2-arachidonylglycerol biosynthetic enzyme, on resident immune cells of the brain (microglia) and the role of this pathway in neuroinflammation, suggest that this enzyme may contribute to TBI-induced neuroinflammation. Accordingly, we tested whether DAGL-β-/- mice would show a protective phenotype from the deleterious consequences of TBI on cognitive and neurological motor functions. Materials and Methods: DAGL-β-/- and -β+/+ mice were subjected to the lateral fluid percussion model of TBI and assessed for learning and memory in the Morris water maze (MWM) Fixed Platform (reference memory) and Reversal (cognitive flexibility) tasks, as well as in a cued MWM task to infer potential sensorimotor/motivational deficits. In addition, subjects were assessed for motor behavior (Rotarod and the Neurological Severity Score assays) and in the light/dark box and the elevated plus maze to infer whether these manipulations affected anxiety-like behavior. Finally, we also examined whether brain injury disrupts the ceramide/sphingolipid lipid signaling system and if DAGL-β deletion offers protection. Results: TBI disrupted all measures of neurological motor function and reduced body weight, but did not affect body temperature or performance in common assays used to infer anxiety. TBI also impaired performance in MWM Fixed Platform and Reversal tasks, but did not affect cued MWM performance. Although no differences were found between DAGL-β-/- and -β+/+ mice in any of these measures, male DAGL-β-/- mice displayed an unexpected survival-protective phenotype, which persisted at increased injury severities. In contrast, TBI did not elicit mortality in female mice regardless of genotype. TBI also produced significant changes in sphingolipid profiles (a family of lipids, members of which have been linked to both apoptotic and antiapoptotic pathways), in which DAGL-β deletion modestly altered levels of select species. Conclusions: These findings indicate that although DAGL-β does not play a necessary role in TBI-induced cognitive and neurological function, it appears to contribute to the increased vulnerability of male mice to TBI-induced mortality, whereas female mice show high survival rates irrespective of DAGL-β expression.
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Affiliation(s)
- Lesley D O'Brien
- Department of Pharmacology and Toxicology, Virginia Commonwealth University, Richmond, Virginia, USA
| | - Terry L Smith
- Department of Anatomy and Neurobiology, Virginia Commonwealth University, Richmond, Virginia, USA
| | - Giulia Donvito
- Department of Pharmacology and Toxicology, Virginia Commonwealth University, Richmond, Virginia, USA
| | - Benjamin F Cravatt
- Department of Molecular Medicine, The Scripps Research Institute, La Jolla, California, USA
| | - Jason Newton
- Department of Biochemistry and Molecular Biology, Virginia Commonwealth University, Richmond, Virginia, USA
| | - Sarah Spiegel
- Department of Biochemistry and Molecular Biology, Virginia Commonwealth University, Richmond, Virginia, USA
| | - Thomas M Reeves
- Department of Anatomy and Neurobiology, Virginia Commonwealth University, Richmond, Virginia, USA
| | - Linda L Phillips
- Department of Anatomy and Neurobiology, Virginia Commonwealth University, Richmond, Virginia, USA
| | - Aron H Lichtman
- Department of Pharmacology and Toxicology, Virginia Commonwealth University, Richmond, Virginia, USA.,Department of Medicinal Chemistry, Virginia Commonwealth University, Richmond, Virginia, USA
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Multiple cannabinoid signaling cascades powerfully suppress recurrent excitation in the hippocampus. Proc Natl Acad Sci U S A 2021; 118:2017590118. [PMID: 33468648 DOI: 10.1073/pnas.2017590118] [Citation(s) in RCA: 14] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
Abstract
Recurrent excitatory neural networks are unstable. In the hippocampus, excitatory mossy cells (MCs) receive strong excitatory inputs from dentate granule cells (GCs) and project back onto the proximal dendrites of GCs. By targeting the ipsi- and contralateral dentate gyrus (DG) along the dorsoventral axis of the hippocampus, MCs form an extensive recurrent excitatory circuit (GC-MC-GC) whose dysregulation can promote epilepsy. We recently reported that a physiologically relevant pattern of MC activity induces a robust form of presynaptic long-term potentiation (LTP) of MC-GC transmission which enhances GC output. Left unchecked, this LTP may interfere with DG-dependent learning, like pattern separation-which relies on sparse GC firing-and may even facilitate epileptic activity. Intriguingly, MC axons display uniquely high expression levels of type-1 cannabinoid receptors (CB1Rs), but their role at MC-GC synapses is poorly understood. Using rodent hippocampal slices, we report that constitutively active CB1Rs, presumably via βγ subunits, selectively inhibited MC inputs onto GCs but not MC inputs onto inhibitory interneurons or CB1R-sensitive inhibitory inputs onto GCs. Tonic CB1R activity also inhibited LTP and GC output. Furthermore, brief endocannabinoid release from GCs dampened MC-GC LTP in two mechanistically distinct ways: during induction via βγ signaling and before induction via αi/o signaling in a form of presynaptic metaplasticity. Lastly, a single in vivo exposure to exogenous cannabinoids was sufficient to induce this presynaptic metaplasticity. By dampening excitatory transmission and plasticity, tonic and phasic CB1R activity at MC axon terminals may preserve the sparse nature of the DG and protect against runaway excitation.
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Tanigami H, Yoneda M, Tabata Y, Echigo R, Kikuchi Y, Yamazaki M, Kishimoto Y, Sakimura K, Kano M, Ohno-Shosaku T. Endocannabinoid Signaling from 2-Arachidonoylglycerol to CB 1 Cannabinoid Receptor Facilitates Reward-based Learning of Motor Sequence. Neuroscience 2019; 421:1-16. [PMID: 31682822 DOI: 10.1016/j.neuroscience.2019.09.040] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/09/2019] [Revised: 09/17/2019] [Accepted: 09/30/2019] [Indexed: 12/27/2022]
Abstract
The endocannabinoid system modulates synaptic transmission, controls neuronal excitability, and is involved in various brain functions including learning and memory. 2-arachidonoylglycerol, a major endocannabinoid produced by diacylglycerol lipase-α (DGLα), is released from postsynaptic neurons, retrogradely activates presynaptic CB1 cannabinoid receptors, and induces short-term or long-term synaptic plasticity. To examine whether and how the endocannabinoid system contributes to reward-based learning of a motor sequence, we subjected male CB1-knockout (KO) and DGLα-KO mice to three types of operant lever-press tasks. First, we trained mice to press one of three levers labeled A, B, and C for a food reward (one-lever task). Second, we trained mice to press the three levers in the order of A, B, and C (three-lever task). Third, the order of the levers was reversed to C, B, and A (reverse three-lever task). We found that CB1-KO mice and DGLα-KO mice exhibited essentially the same deficits in the operant lever-press tasks. In the one-lever task, both strains of knockout mice showed a slower rate of learning to press a lever for food. In the three-lever task, both strains of knockout mice showed a slower rate of learning of the motor sequence. In the reverse three-lever task, both strains of knockout mice needed more lever presses for reversal learning. These results suggest that the endocannabinoid system facilitates reward-based learning of a motor sequence by conferring the flexibility with which animals can switch between strategies.
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Affiliation(s)
- Hayate Tanigami
- Faculty of Health Sciences, Institute of Medical, Pharmaceutical and Health Sciences, Kanazawa University, Kanazawa 920-0942, Japan
| | - Mitsugu Yoneda
- Faculty of Health Sciences, Institute of Medical, Pharmaceutical and Health Sciences, Kanazawa University, Kanazawa 920-0942, Japan
| | - Yuki Tabata
- Faculty of Health Sciences, Institute of Medical, Pharmaceutical and Health Sciences, Kanazawa University, Kanazawa 920-0942, Japan
| | - Ryosuke Echigo
- Faculty of Health Sciences, Institute of Medical, Pharmaceutical and Health Sciences, Kanazawa University, Kanazawa 920-0942, Japan
| | - Yui Kikuchi
- Faculty of Health Sciences, Institute of Medical, Pharmaceutical and Health Sciences, Kanazawa University, Kanazawa 920-0942, Japan
| | - Maya Yamazaki
- Department of Cellular Neurobiology, Brain Research Institute, Niigata University, Niigata 951-8585, Japan
| | - Yasushi Kishimoto
- Laboratory of Neurobiophysics, Kagawa School of Pharmaceutical Sciences, Tokushima Bunri University, Sanuki, Kagawa 769-2193, Japan
| | - Kenji Sakimura
- Department of Cellular Neurobiology, Brain Research Institute, Niigata University, Niigata 951-8585, Japan
| | - Masanobu Kano
- Department of Neurophysiology, Graduate School of Medicine, The University of Tokyo, Tokyo 113-0033, Japan; International Research Center for Neurointelligence (WPI-IRCN), The University of Tokyo Institutes for Advanced Study (UTIAS), The University of Tokyo, Tokyo 113-0033, Japan
| | - Takako Ohno-Shosaku
- Faculty of Health Sciences, Institute of Medical, Pharmaceutical and Health Sciences, Kanazawa University, Kanazawa 920-0942, Japan.
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Li RS, Fukumori R, Takeda T, Song Y, Morimoto S, Kikura-Hanajiri R, Yamaguchi T, Watanabe K, Aritake K, Tanaka Y, Yamada H, Yamamoto T, Ishii Y. Elevation of endocannabinoids in the brain by synthetic cannabinoid JWH-018: mechanism and effect on learning and memory. Sci Rep 2019; 9:9621. [PMID: 31270353 PMCID: PMC6610139 DOI: 10.1038/s41598-019-45969-4] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/22/2019] [Accepted: 06/19/2019] [Indexed: 02/06/2023] Open
Abstract
The impairment of learning and memory is a well-documented effect of both natural and synthetic cannabinoids. In the present study, we aimed to investigate the effect of acute administration of JWH-018, a synthetic cannabinoid, on the hippocampal metabolome to assess biochemical changes in vivo. JWH-018 elevated levels of the endocannabinoids, anandamide (AEA) and 2-arachidonoylglycerol (2-AG). The increase of endocannabinoid levels in response to JWH-018 could be inhibited by co-administration of AM251, a CB1 receptor antagonist. Biochemical analyses revealed that this was the result of suppression of two hydrolases involved in endocannabinoid degradation (fatty acid amide hydrolase [FAAH] and monoacylglycerol lipase [MAGL]). Additionally, we showed that JWH-018 causes a reduction in the levels of brain-derived neurotrophic factor (BDNF), which is known to modulate synaptic plasticity and adaptive processes underlying learning and memory. The decrease of BDNF following JWH-018 treatment was also rescued by co-administration of AM251. As both endocannabinoids and BDNF have been shown to modulate learning and memory in the hippocampus, the alteration of their levels in response to JWH-018 may explain the contribution of synthetic cannabinoids to impairment of memory.
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Affiliation(s)
- Ren-Shi Li
- Laboratory of Molecular Life Sciences, Graduate School of Pharmaceutical Sciences, Kyushu University, 3-1-1 Maidashi, Higashi-ku, Fukuoka, 812-8582, Japan.,Research Department of Pharmacognosy, China Pharmaceutical University, Nanjing, 211198, People's Republic of China
| | - Ryo Fukumori
- Department of Pharmacotherapeutics and Neuropsychopharmacology, Faculty of Pharmaceutical Sciences, Nagasaki International University, Sasebo, Nagasaki, Japan
| | - Tomoki Takeda
- Laboratory of Molecular Life Sciences, Graduate School of Pharmaceutical Sciences, Kyushu University, 3-1-1 Maidashi, Higashi-ku, Fukuoka, 812-8582, Japan
| | - Yingxia Song
- Laboratory of Molecular Life Sciences, Graduate School of Pharmaceutical Sciences, Kyushu University, 3-1-1 Maidashi, Higashi-ku, Fukuoka, 812-8582, Japan
| | - Satoshi Morimoto
- Division of Pharmacognosy, Graduate School of Pharmaceutical Sciences, Kyushu University, 3-1-1 Maidashi, Higashi-ku, Fukuoka, 812-8582, Japan
| | - Ruri Kikura-Hanajiri
- Division of Pharmacognosy, Phytochemistry and Narcotics, National Institute of Health Sciences (NIHS), 3-25-26 Tonomachi, Kawasaki-ku, Kawasaki-city, Kanagawa, 210-9501, Japan
| | - Taku Yamaguchi
- Department of Pharmacotherapeutics and Neuropsychopharmacology, Faculty of Pharmaceutical Sciences, Nagasaki International University, Sasebo, Nagasaki, Japan
| | - Kazuhito Watanabe
- Daiichi University of Pharmacy, 22-1 Tamagawa-cho, Minami-ku Fukuoka, 815-8511, Japan
| | - Kousuke Aritake
- Daiichi University of Pharmacy, 22-1 Tamagawa-cho, Minami-ku Fukuoka, 815-8511, Japan
| | - Yoshitaka Tanaka
- Division of Pharmaceutical Cell Biology, Graduate School of Pharmaceutical Sciences, Kyushu University, 3-1-1 Maidashi, Higashi-ku, Fukuoka, 812-8582, Japan
| | - Hideyuki Yamada
- Laboratory of Molecular Life Sciences, Graduate School of Pharmaceutical Sciences, Kyushu University, 3-1-1 Maidashi, Higashi-ku, Fukuoka, 812-8582, Japan
| | - Tsuneyuki Yamamoto
- Department of Pharmacotherapeutics and Neuropsychopharmacology, Faculty of Pharmaceutical Sciences, Nagasaki International University, Sasebo, Nagasaki, Japan
| | - Yuji Ishii
- Laboratory of Molecular Life Sciences, Graduate School of Pharmaceutical Sciences, Kyushu University, 3-1-1 Maidashi, Higashi-ku, Fukuoka, 812-8582, Japan.
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Diacylglycerol Lipase-Alpha Regulates Hippocampal-Dependent Learning and Memory Processes in Mice. J Neurosci 2019; 39:5949-5965. [PMID: 31127001 DOI: 10.1523/jneurosci.1353-18.2019] [Citation(s) in RCA: 17] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/27/2018] [Revised: 04/24/2019] [Accepted: 05/11/2019] [Indexed: 12/18/2022] Open
Abstract
Diacylglycerol lipase-α (DAGL-α), the principal biosynthetic enzyme of the endogenous cannabinoid 2-arachidonylglycerol (2-AG) on neurons, plays a key role in CB1 receptor-mediated synaptic plasticity and hippocampal neurogenesis, but its contribution to global hippocampal-mediated processes remains unknown. Thus, the present study examines the role that DAGL-α plays on LTP in hippocampus, as well as in hippocampal-dependent spatial learning and memory tasks, and on the production of endocannabinoid and related lipids through the use of complementary pharmacologic and genetic approaches to disrupt this enzyme in male mice. Here we show that DAGL-α gene deletion or pharmacological inhibition disrupts LTP in CA1 of the hippocampus but elicits varying magnitudes of behavioral learning and memory deficits in mice. In particular, DAGL-α-/- mice display profound impairments in the Object Location assay and Morris Water Maze (MWM) acquisition engaging in nonspatial search strategies. In contrast, WT mice administered the DAGL-α inhibitor DO34 show delays in MWM acquisition and reversal learning, but no deficits in expression, extinction, forgetting, or perseveration processes in this task, as well as no impairment in Object Location. The deficits in synaptic plasticity and MWM performance occur in concert with decreased 2-AG and its major lipid metabolite (arachidonic acid), but increases of a 2-AG diacylglycerol precursor in hippocampus, PFC, striatum, and cerebellum. These novel behavioral and electrophysiological results implicate a direct and perhaps selective role of DAGL-α in the integration of new spatial information.SIGNIFICANCE STATEMENT Here we show that genetic deletion or pharmacologic inhibition of diacylglycerol lipase-α (DAGL-α) impairs hippocampal CA1 LTP, differentially disrupts spatial learning and memory performance in Morris water maze (MWM) and Object Location tasks, and alters brain levels of endocannabinoids and related lipids. Whereas DAGL-α-/- mice exhibit profound phenotypic spatial memory deficits, a DAGL inhibitor selectively impairs the integration of new information in MWM acquisition and reversal tasks, but not memory processes of expression, extinction, forgetting, or perseveration, and does not affect performance in the Objection Location task. The findings that constitutive or short-term DAGL-α disruption impairs learning and memory at electrophysiological and selective in vivo levels implicate this enzyme as playing a key role in the integration of new spatial information.
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de Sousa LP, de Almeida RF, Ribeiro-Gomes FL, de Moura Carvalho LJ, E Souza TM, de Souza DOG, Daniel-Ribeiro CT. Long-term effect of uncomplicated Plasmodium berghei ANKA malaria on memory and anxiety-like behaviour in C57BL/6 mice. Parasit Vectors 2018; 11:191. [PMID: 29554958 PMCID: PMC5859440 DOI: 10.1186/s13071-018-2778-8] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/21/2017] [Accepted: 03/06/2018] [Indexed: 01/28/2023] Open
Abstract
Background Cerebral malaria, the main complication of Plasmodium falciparum infection in humans, is associated with persistent neurocognitive sequels both in human disease and the murine experimental model. In recent years, cognitive deficits related to uncomplicated (non-cerebral) malaria have also been reported in chronically exposed residents of endemic areas, but not in some murine experimental models of non-cerebral malaria. This study aimed at evaluating the influence of uncomplicated malaria on different behavioural paradigms associated with memory and anxiety-like parameters in a murine model that has the ability to develop cerebral malaria. Methods Plasmodium berghei ANKA-infected and non-infected C57BL/6 mice were used. Development of cerebral malaria was prevented by chloroquine treatment starting on the fourth day of infection. The control group (non-infected mice) were treated with PBS. The effect of uncomplicated malaria infection on locomotor habituation, short and long-term memory and anxious-like behaviour was evaluated 64 days after parasite clearance in assays including open field, object recognition, Y-maze and light/dark tasks. Results Plasmodium berghei ANKA-infected mice showed significant long-lasting disturbances reflected by a long-term memory-related behaviour on open field and object recognition tasks, accompanied by an anxious-like phenotype availed on open field and light-dark tasks. Conclusions Long-term neurocognitive sequels may follow an uncomplicated malaria episode in an experimental model prone to develop cerebral malaria, even if the infection is treated before the appearance of clinical signs of cerebral impairment.
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Affiliation(s)
- Luciana Pereira de Sousa
- Laboratório de Pesquisa em Malária, Instituto Oswaldo Cruz & Centro de Pesquisa, Diagnóstico e Treinamento em Malária (CPD-Mal) da Fundação Oswaldo Cruz (Fiocruz) e da Secretaria de Vigilância em Saúde (SVS), Ministério da Saúde, Rio de Janeiro, Brazil.
| | - Roberto Farina de Almeida
- Instituto de Ciências Básicas da Saúde, Departamento de Bioquímica, Universidade Federal do Rio Grande do Sul, Porto Alegre, Brazil
| | - Flávia Lima Ribeiro-Gomes
- Laboratório de Pesquisa em Malária, Instituto Oswaldo Cruz & Centro de Pesquisa, Diagnóstico e Treinamento em Malária (CPD-Mal) da Fundação Oswaldo Cruz (Fiocruz) e da Secretaria de Vigilância em Saúde (SVS), Ministério da Saúde, Rio de Janeiro, Brazil
| | - Leonardo José de Moura Carvalho
- Laboratório de Pesquisa em Malária, Instituto Oswaldo Cruz & Centro de Pesquisa, Diagnóstico e Treinamento em Malária (CPD-Mal) da Fundação Oswaldo Cruz (Fiocruz) e da Secretaria de Vigilância em Saúde (SVS), Ministério da Saúde, Rio de Janeiro, Brazil
| | - Tadeu Mello E Souza
- Instituto de Ciências Básicas da Saúde, Departamento de Bioquímica, Universidade Federal do Rio Grande do Sul, Porto Alegre, Brazil
| | - Diogo Onofre Gomes de Souza
- Instituto de Ciências Básicas da Saúde, Departamento de Bioquímica, Universidade Federal do Rio Grande do Sul, Porto Alegre, Brazil
| | - Cláudio Tadeu Daniel-Ribeiro
- Laboratório de Pesquisa em Malária, Instituto Oswaldo Cruz & Centro de Pesquisa, Diagnóstico e Treinamento em Malária (CPD-Mal) da Fundação Oswaldo Cruz (Fiocruz) e da Secretaria de Vigilância em Saúde (SVS), Ministério da Saúde, Rio de Janeiro, Brazil.
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Spinal protein kinase C/extracellular signal–regulated kinase signal pathway mediates hyperalgesia priming. Pain 2018; 159:907-918. [DOI: 10.1097/j.pain.0000000000001162] [Citation(s) in RCA: 15] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/25/2022]
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Colangeli R, Pierucci M, Benigno A, Campiani G, Butini S, Di Giovanni G. The FAAH inhibitor URB597 suppresses hippocampal maximal dentate afterdischarges and restores seizure-induced impairment of short and long-term synaptic plasticity. Sci Rep 2017; 7:11152. [PMID: 28894217 PMCID: PMC5593993 DOI: 10.1038/s41598-017-11606-1] [Citation(s) in RCA: 32] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/16/2017] [Accepted: 08/25/2017] [Indexed: 11/09/2022] Open
Abstract
Synthetic cannabinoids and phytocannabinoids have been shown to suppress seizures both in humans and experimental models of epilepsy. However, they generally have a detrimental effect on memory and memory-related processes. Here we compared the effect of the inhibition of the endocannabinoid (eCB) degradation versus synthetic CB agonist on limbic seizures induced by maximal dentate activation (MDA) acute kindling. Moreover, we investigated the dentate gyrus (DG) granule cell reactivity and synaptic plasticity in naïve and in MDA-kindled anaesthetised rats. We found that both the fatty acid amide hydrolase (FAAH) inhibitor URB597 and the synthetic cannabinoid agonist WIN55,212-2 displayed AM251-sensitive anti-seizure effects. WIN55,212-2, dose-dependently (0.5-2 mg/kg, i.p.) impaired short-term plasticity (STP) and long-term potentiation (LTP) at perforant path-DG synapses in naïve rats. Strikingly, URB597 (1 mg/kg, i.p.) was devoid of any deleterious effects in normal conditions, while it prevented seizure-induced alterations of both STP and LTP. Our evidence indicates that boosting the eCB tone rather than general CB1 activation might represent a potential strategy for the development of a new class of drugs for treatment of both seizures and comorbid memory impairments associated with epilepsy.
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Affiliation(s)
- Roberto Colangeli
- Laboratory of Neurophysiology, Department of Physiology and Biochemistry, Faculty of Medicine and Surgery, University of Malta, Msida, Malta.
| | - Massimo Pierucci
- Laboratory of Neurophysiology, Department of Physiology and Biochemistry, Faculty of Medicine and Surgery, University of Malta, Msida, Malta
| | - Arcangelo Benigno
- Department of Experimental Biomedicine and Clinical Neurosciences (BIONEC), Human Physiology Section, University of Palermo, Palermo, Italy
| | - Giuseppe Campiani
- European Research Centre for Drug Discovery and Development (NatSynDrugs) and Department of Biotechnology, Chemistry, and Pharmacy, Università degli Studi di Siena, Siena, Italy
| | - Stefania Butini
- European Research Centre for Drug Discovery and Development (NatSynDrugs) and Department of Biotechnology, Chemistry, and Pharmacy, Università degli Studi di Siena, Siena, Italy
| | - Giuseppe Di Giovanni
- Laboratory of Neurophysiology, Department of Physiology and Biochemistry, Faculty of Medicine and Surgery, University of Malta, Msida, Malta. .,School of Biosciences, Cardiff University, Cardiff, UK.
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A Primary Cortical Input to Hippocampus Expresses a Pathway-Specific and Endocannabinoid-Dependent Form of Long-Term Potentiation. eNeuro 2016; 3:eN-NWR-0160-16. [PMID: 27517090 PMCID: PMC4976302 DOI: 10.1523/eneuro.0160-16.2016] [Citation(s) in RCA: 54] [Impact Index Per Article: 6.8] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/14/2016] [Revised: 07/14/2016] [Accepted: 07/15/2016] [Indexed: 02/03/2023] Open
Abstract
The endocannabinoid 2-arachidonoyl-sn-glycerol (2-AG), a key modulator of synaptic transmission in mammalian brain, is produced in dendritic spines and then crosses the synaptic junction to depress neurotransmitter release. Here we report that 2-AG-dependent retrograde signaling also mediates an enduring enhancement of glutamate release, as assessed with independent tests, in the lateral perforant path (LPP), one of two cortical inputs to the granule cells of the dentate gyrus. Induction of this form of long-term potentiation (LTP) involved two types of glutamate receptors, changes in postsynaptic calcium, and the postsynaptic enzyme that synthesizes 2-AG. Stochastic optical reconstruction microscopy confirmed that CB1 cannabinoid receptors are localized presynaptically to LPP terminals, while the inhibition or knockout of the receptors eliminated LPP-LTP. Suppressing the enzyme that degrades 2-AG dramatically enhanced LPP potentiation, while overexpressing it produced the opposite effect. Priming with a CB1 agonist markedly reduced the threshold for LTP. Latrunculin A, which prevents actin polymerization, blocked LPP-LTP when applied extracellularly but had no effect when infused postsynaptically into granule cells, indicating that critical actin remodeling resides in the presynaptic compartment. Importantly, there was no evidence for the LPP form of potentiation in the Schaffer-commissural innervation of field CA1 or in the medial perforant path. Peripheral injections of compounds that block or enhance LPP-LTP had corresponding effects on the formation of long-term memory for cues conveyed to the dentate gyrus by the LPP. Together, these results indicate that the encoding of information carried by a principal hippocampal afferent involves an unusual, regionally differentiated form of plasticity.
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Sugaya Y, Yamazaki M, Uchigashima M, Kobayashi K, Watanabe M, Sakimura K, Kano M. Crucial Roles of the Endocannabinoid 2-Arachidonoylglycerol in the Suppression of Epileptic Seizures. Cell Rep 2016; 16:1405-1415. [PMID: 27452464 DOI: 10.1016/j.celrep.2016.06.083] [Citation(s) in RCA: 52] [Impact Index Per Article: 6.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/09/2015] [Revised: 05/01/2016] [Accepted: 06/21/2016] [Indexed: 01/13/2023] Open
Abstract
Endocannabinoid signaling is considered to suppress excessive excitability of neural circuits and to protect the brain from seizures. However, the precise mechanisms of this effect are poorly understood. Here, we report that 2-arachidonoylglycerol (2-AG), one of the two major endocannabinoids, is crucial for suppressing seizures. We found that kainate-induced seizures in mice lacking the 2-AG synthesizing enzyme, diacylglycerol lipase α, were much more severe compared with those in cannabinoid CB1 receptor knockout mice and were comparable to those in mice lacking both CB1- and CB2-receptor-mediated signaling. In the dentate gyrus, 2-AG suppressed excitatory input around the inner and middle molecular layers through CB1 and presumably CB2 receptors, respectively. This 2-AG-mediated suppression contributed to decreased granule cell excitability and the dampening of seizures. Furthermore, lack of 2-AG signaling enhanced kindling epileptogenesis and spontaneous seizures after kainate-induced status epilepticus. These results highlight critical roles of 2-AG signaling in the suppression of epileptic seizures.
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Affiliation(s)
- Yuki Sugaya
- Department of Neurophysiology, Graduate School of Medicine, The University of Tokyo, Tokyo 113-0033, Japan
| | - Maya Yamazaki
- Department of Cellular Neurobiology, Brain Research Institute, Niigata University, Niigata 951-8585, Japan
| | - Motokazu Uchigashima
- Department of Anatomy and Embryology, Graduate School of Medicine, Hokkaido University, Sapporo 060-8638, Japan
| | - Kenta Kobayashi
- Section of Viral Vector Development, National Institute for Physiological Sciences, Okazaki 444-8585, Japan
| | - Masahiko Watanabe
- Department of Anatomy and Embryology, Graduate School of Medicine, Hokkaido University, Sapporo 060-8638, Japan
| | - Kenji Sakimura
- Department of Cellular Neurobiology, Brain Research Institute, Niigata University, Niigata 951-8585, Japan
| | - Masanobu Kano
- Department of Neurophysiology, Graduate School of Medicine, The University of Tokyo, Tokyo 113-0033, Japan.
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Guggenhuber S, Romo-Parra H, Bindila L, Leschik J, Lomazzo E, Remmers F, Zimmermann T, Lerner R, Klugmann M, Pape HC, Lutz B. Impaired 2-AG Signaling in Hippocampal Glutamatergic Neurons: Aggravation of Anxiety-Like Behavior and Unaltered Seizure Susceptibility. Int J Neuropsychopharmacol 2015; 19:pyv091. [PMID: 26232789 PMCID: PMC4772822 DOI: 10.1093/ijnp/pyv091] [Citation(s) in RCA: 31] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 04/20/2015] [Accepted: 07/29/2015] [Indexed: 12/21/2022] Open
Abstract
BACKGROUND Postsynaptically generated 2-arachidonoylglycerol activates the presynaptic cannabinoid type-1 receptor, which is involved in synaptic plasticity at both glutamatergic and GABAergic synapses. However, the differential function of 2-arachidonoylglycerol signaling at glutamatergic vs GABAergic synapses in the context of animal behavior has not been investigated yet. METHODS Here, we analyzed the role of 2-arachidonoylglycerol signaling selectively in hippocampal glutamatergic neurons. Monoacylglycerol lipase, the primary degrading enzyme of 2-arachidonoylglycerol, is expressed at presynaptic sites of excitatory and inhibitory neurons. By adeno-associated virus-mediated overexpression of monoacylglycerol lipase in glutamatergic neurons of the mouse hippocampus, we selectively interfered with 2-arachidonoylglycerol signaling at glutamatergic synapses of these neurons. RESULTS Genetic modification of monoacylglycerol lipase resulted in a 50% decrease in 2-arachidonoylglycerol tissue levels without affecting the content of the second major endocannabinoid anandamide. A typical electrophysiological read-out for 2-arachidonoylglycerol signaling is the depolarization-induced suppression of excitation and of inhibition. Elevated monoacylglycerol lipase levels at glutamatergic terminals selectively impaired depolarization-induced suppression of excitation, while depolarization-induced suppression of inhibition was not significantly changed. At the behavioral level, mice with impaired hippocampal glutamatergic 2-arachidonoylglycerol signaling exhibited increased anxiety-like behavior but showed no alterations in aversive memory formation and seizure susceptibility. CONCLUSION Our data indicate that 2-arachidonoylglycerol signaling selectively in hippocampal glutamatergic neurons is essential for the animal's adaptation to aversive situations.
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Affiliation(s)
| | | | | | | | | | | | | | | | | | | | - Beat Lutz
- Institute of Physiological Chemistry, University Medical Center of the Johannes Gutenberg University, Mainz, Germany (Dr Guggenhuber, Dr Bindila, Dr Leschik, Dr Lomazzo, Dr Remmers, Ms Zimmermann, Ms Lerner, Dr Klugmann, and Dr Lutz); Institute of Physiology I (Neurophysiology), Westfaelische Wilhelms-University, Muenster, Germany (Drs Romo-Parra and Pape); Translational Neuroscience Facility, Department of Physiology, School of Medical Sciences, University of New South Wales, UNSW Kensington Campus, Sydney, NSW, Australia (Dr Klugmann).
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13
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Kishimoto Y, Cagniard B, Yamazaki M, Nakayama J, Sakimura K, Kirino Y, Kano M. Task-specific enhancement of hippocampus-dependent learning in mice deficient in monoacylglycerol lipase, the major hydrolyzing enzyme of the endocannabinoid 2-arachidonoylglycerol. Front Behav Neurosci 2015; 9:134. [PMID: 26082696 PMCID: PMC4451424 DOI: 10.3389/fnbeh.2015.00134] [Citation(s) in RCA: 27] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/17/2015] [Accepted: 05/11/2015] [Indexed: 12/03/2022] Open
Abstract
Growing evidence indicates that the endocannabinoid system is important for the acquisition and/or extinction of learning and memory. However, it is unclear which endocannabinoid(s) play(s) a crucial role in these cognitive functions, especially memory extinction. To elucidate the physiological role of 2-arachidonoylglycerol (2-AG), a major endocannabinoid, in behavioral and cognitive functions, we conducted a comprehensive behavioral test battery in knockout (KO) mice deficient in monoacylglycerol lipase (MGL), the major hydrolyzing enzyme of 2-AG. We found age-dependent increases in spontaneous physical activity (SPA) in MGL KO mice. Next, we tested the MGL KO mice using 5 hippocampus-dependent learning paradigms (i.e., Morris water maze (MWM), contextual fear conditioning, novel object recognition test, trace eyeblink conditioning, and water-finding test). In the MWM, MGL KO mice showed normal acquisition of reference memory, but exhibited significantly faster extinction of the learned behavior. Moreover, they showed faster memory acquisition on the reversal-learning task of the MWM. In contrast, in the contextual fear conditioning, MGL KO mice tended to show slower memory extinction. In the novel object recognition and water-finding tests, MGL KO mice exhibited enhanced memory acquisition. Trace eyeblink conditioning was not altered in MGL KO mice throughout the acquisition and extinction phases. These results indicate that 2-AG signaling is important for hippocampus-dependent learning and memory, but its contribution is highly task-dependent.
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Affiliation(s)
- Yasushi Kishimoto
- Laboratory of Neurobiophysics, Kagawa School of Pharmaceutical Sciences, Tokushima Bunri University Sanuki, Kagawa, Japan
| | - Barbara Cagniard
- Department of Neurophysiology, Graduate School of Medicine, The University of Tokyo Bunkyo-ku, Tokyo, Japan
| | - Maya Yamazaki
- Department of Cellular Neurobiology, Brain Research Institute, Niigata University Niigata, Japan
| | - Junko Nakayama
- Laboratory of Neurobiophysics, Kagawa School of Pharmaceutical Sciences, Tokushima Bunri University Sanuki, Kagawa, Japan
| | - Kenji Sakimura
- Department of Cellular Neurobiology, Brain Research Institute, Niigata University Niigata, Japan
| | - Yutaka Kirino
- Laboratory of Neurobiophysics, Kagawa School of Pharmaceutical Sciences, Tokushima Bunri University Sanuki, Kagawa, Japan
| | - Masanobu Kano
- Department of Neurophysiology, Graduate School of Medicine, The University of Tokyo Bunkyo-ku, Tokyo, Japan
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14
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Abstract
The physiological and pathophysiological functions of the endocannabinoid system have been studied extensively using transgenic and targeted knockout mouse models. The first gene deletions of the cannabinoid CB(1) receptor were described in the late 1990s, soon followed by CB(2) and FAAH mutations in early 2000. These mouse models helped to elucidate the fundamental role of endocannabinoids as retrograde transmitters in the CNS and in the discovery of many unexpected endocannabinoid functions, for example, in the skin, bone and liver. We now have knockout mouse models for almost every receptor and enzyme of the endocannabinoid system. Conditional mutant mice were mostly developed for the CB(1) receptor, which is widely expressed on many different neurons, astrocytes and microglia, as well as on many cells outside the CNS. These mouse strains include "floxed" CB(1) alleles and mice with a conditional re-expression of CB(1). The availability of these mice made it possible to decipher the function of CB(1) in specific neuronal circuits and cell populations or to discriminate between central and peripheral effects. Many of the genetic mouse models were also used in combination with viral expression systems. The purpose of this review is to provide a comprehensive overview of the existing genetic models and to summarize some of the most important discoveries that were made with these animals.
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MESH Headings
- Amidohydrolases/genetics
- Amidohydrolases/metabolism
- Animals
- Endocannabinoids/genetics
- Endocannabinoids/metabolism
- Gene Deletion
- Gene Expression Regulation
- Genotype
- Humans
- Hydrolysis
- Mice, Knockout
- Mice, Mutant Strains
- Monoacylglycerol Lipases/genetics
- Monoacylglycerol Lipases/metabolism
- Mutation
- Phenotype
- Receptor, Cannabinoid, CB1/genetics
- Receptor, Cannabinoid, CB1/metabolism
- Receptor, Cannabinoid, CB2/genetics
- Receptor, Cannabinoid, CB2/metabolism
- Signal Transduction/genetics
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Affiliation(s)
- Andreas Zimmer
- Institute of Molecular Psychiatry, University of Bonn, Bonn, Germany.
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