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League AF, Yadav-Samudrala BJ, Kolagani R, Cline CA, Jacobs IR, Manke J, Niphakis MJ, Cravatt BF, Lichtman AH, Ignatowska-Jankowska BM, Fitting S. A helping HAND: therapeutic potential of MAGL inhibition against HIV-1-associated neuroinflammation. Front Immunol 2024; 15:1374301. [PMID: 38835765 PMCID: PMC11148243 DOI: 10.3389/fimmu.2024.1374301] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/21/2024] [Accepted: 04/25/2024] [Indexed: 06/06/2024] Open
Abstract
Background Human immunodeficiency virus (HIV) affects nearly 40 million people globally, with roughly 80% of all people living with HIV receiving antiretroviral therapy. Antiretroviral treatment suppresses viral load in peripheral tissues but does not effectively penetrate the blood-brain barrier. Thus, viral reservoirs persist in the central nervous system and continue to produce low levels of inflammatory factors and early viral proteins, including the transactivator of transcription (Tat). HIV Tat is known to contribute to chronic neuroinflammation and synaptodendritic damage, which is associated with the development of cognitive, motor, and/or mood problems, collectively known as HIV-associated neurocognitive disorders (HAND). Cannabinoid anti-inflammatory effects are well documented, but therapeutic utility of cannabis remains limited due to its psychotropic effects, including alterations within brain regions encoding reward processing and motivation, such as the nucleus accumbens. Alternatively, inhibiting monoacylglycerol lipase (MAGL) has demonstrated therapeutic potential through interactions with the endocannabinoid system. Methods The present study utilized a reward-related operant behavioral task to quantify motivated behavior in female Tat transgenic mice treated with vehicle or MAGL inhibitor MJN110 (1 mg/kg). Brain tissue was collected to assess dendritic injury and neuroinflammatory profiles, including dendritic microtubule-associated protein (MAP2ab) intensity, microglia density, microglia morphology, astrocyte density, astrocytic interleukin-1ß (IL-1ß) colocalization, and various lipid mediators. Results No significant behavioral differences were observed; however, MJN110 protected against Tat-induced dendritic injury by significantly upregulating MAP2ab intensity in the nucleus accumbens and in the infralimbic cortex of Tat(+) mice. No or only minor effects were noted for Iba-1+ microglia density and/or microglia morphology. Further, Tat increased GFAP+ astrocyte density in the infralimbic cortex and GFAP+ astrocytic IL-1ß colocalization in the nucleus accumbens, with MJN110 significantly reducing these measures in Tat(+) subjects. Lastly, selected HETE-related inflammatory lipid mediators in the striatum were downregulated by chronic MJN110 treatment. Conclusions These findings demonstrate anti-inflammatory and neuroprotective properties of MJN110 without cannabimimetic behavioral effects and suggest a promising alternative to cannabis for managing neuroinflammation.
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Affiliation(s)
- Alexis F. League
- Department of Psychology and Neuroscience, University of North Carolina at Chapel Hill, Chapel Hill, NC, United States
| | - Barkha J. Yadav-Samudrala
- Department of Psychology and Neuroscience, University of North Carolina at Chapel Hill, Chapel Hill, NC, United States
| | - Ramya Kolagani
- Department of Psychology and Neuroscience, University of North Carolina at Chapel Hill, Chapel Hill, NC, United States
| | - Calista A. Cline
- Department of Psychology and Neuroscience, University of North Carolina at Chapel Hill, Chapel Hill, NC, United States
| | - Ian R. Jacobs
- Department of Psychology and Neuroscience, University of North Carolina at Chapel Hill, Chapel Hill, NC, United States
| | - Jonathan Manke
- Department of Pharmaceutical Sciences, Skaggs School of Pharmacy and Pharmaceutical Sciences, University of Colorado Anschutz Medical Campus, Aurora, CO, United States
| | - Micah J. Niphakis
- Department of Chemistry, Scripps Research, La Jolla, CA, United States
| | | | - Aron H. Lichtman
- Department of Pharmacology and Toxicology, Virginia Commonwealth University, Richmond, VA, United States
| | | | - Sylvia Fitting
- Department of Psychology and Neuroscience, University of North Carolina at Chapel Hill, Chapel Hill, NC, United States
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Luján MÁ, Covey DP, Young-Morrison R, Zhang L, Kim A, Morgado F, Patel S, Bass CE, Paladini C, Cheer JF. Mobilization of endocannabinoids by midbrain dopamine neurons is required for the encoding of reward prediction. Nat Commun 2023; 14:7545. [PMID: 37985770 PMCID: PMC10662422 DOI: 10.1038/s41467-023-43131-3] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/31/2023] [Accepted: 11/01/2023] [Indexed: 11/22/2023] Open
Abstract
Brain levels of the endocannabinoid 2-arachidonoylglycerol (2-AG) shape motivated behavior and nucleus accumbens (NAc) dopamine release. However, it is not clear whether mobilization of 2-AG specifically from midbrain dopamine neurons is necessary for dopaminergic responses to external stimuli predicting forthcoming reward. Here, we use a viral-genetic strategy to prevent the expression of the 2-AG-synthesizing enzyme diacylglycerol lipase α (DGLα) from ventral tegmental area (VTA) dopamine cells in adult mice. We find that DGLα deletion from VTA dopamine neurons prevents depolarization-induced suppression of excitation (DSE), a form of 2-AG-mediated synaptic plasticity, in dopamine neurons. DGLα deletion also decreases effortful, cue-driven reward-seeking but has no effect on non-cued or low-effort operant tasks and other behaviors. Moreover, dopamine recording in the NAc reveals that deletion of DGLα impairs the transfer of accumbal dopamine signaling from a reward to its earliest predictors. These results demonstrate that 2-AG mobilization from VTA dopamine neurons is a necessary step for the generation of dopamine-based predictive associations that are required to direct and energize reward-oriented behavior.
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Affiliation(s)
- Miguel Á Luján
- Department of Neurobiology, University of Maryland School of Medicine, Baltimore, MD, USA
| | - Dan P Covey
- Department of Neurobiology, University of Maryland School of Medicine, Baltimore, MD, USA
- Department of Neuroscience, Lovelace Biomedical Research Institute, Albuquerque, NM, USA
| | - Reana Young-Morrison
- Department of Neurobiology, University of Maryland School of Medicine, Baltimore, MD, USA
| | - LanYuan Zhang
- Department of Neurobiology, University of Maryland School of Medicine, Baltimore, MD, USA
| | - Andrew Kim
- Department of Neurobiology, University of Maryland School of Medicine, Baltimore, MD, USA
| | - Fiorella Morgado
- Department of Neurobiology, University of Maryland School of Medicine, Baltimore, MD, USA
| | - Sachin Patel
- Northwestern Center for Psychiatric Neuroscience, Department of Psychiatry and Behavioral Sciences, Northwestern University Feinberg School of Medicine, Chicago, IL, USA
| | - Caroline E Bass
- Department of Pharmacology and Toxicology, University at Buffalo, State University of New York, Buffalo, NY, USA
| | - Carlos Paladini
- UTSA Neuroscience Institute, University of Texas at San Antonio, San Antonio, TX, USA
| | - Joseph F Cheer
- Department of Neurobiology, University of Maryland School of Medicine, Baltimore, MD, USA.
- Department of Psychiatry, University of Maryland School of Medicine, Baltimore, MD, USA.
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3
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Clark ML, Abimanyi-Ochom J, Le H, Long B, Orr C, Khanh-Dao Le L. A systematic review and meta-analysis of depression and apathy frequency in adult-onset Huntington's disease. Neurosci Biobehav Rev 2023; 149:105166. [PMID: 37054804 DOI: 10.1016/j.neubiorev.2023.105166] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/18/2022] [Revised: 04/07/2023] [Accepted: 04/09/2023] [Indexed: 04/15/2023]
Abstract
Depression and apathy are associated with decreased functional capacity in Huntington's disease (HD) but frequency of depression and apathy in HD is largely unknown. Systematic literature searching was conducted across 21 databases until 30 June 2021. Inclusion criteria was limited to clinician-rated assessments of depression and apathy and adult-onset HD. Inverse-variance heterogeneity meta-analyses were conducted exploring depression and apathy frequency within individuals from families affected by HD, and within individuals with confirmed HD gene-positive status. Screening identified 289 articles for full-text review; nine remained for meta-analysis. Depression frequency in the lifetime in adults affected by or at-risk for HD was 38%, I2 = 99%. Apathy frequency in the lifetime in adults affected by or at-risk for HD was 40%, I2 = 96%. The robustness of the findings improved when limiting the analysis to gene-positive individuals only where apathy was found to be slightly more common than depression, 48% and 43% respectively. Future studies may consider reporting results from juvenile-onset HD and adult-onset HD cohorts separately to further explore phenotypic profiles.
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Affiliation(s)
- Melanie L Clark
- Deakin University, Deakin Health Economics, School of Health and Social Development, Geelong, Victoria, 3220, Australia; Neurosciences Unit, North Metropolitan Health Services Mental Health Public Health Dental Services, Perth, Western Australia; Perron Institute for Neurological and Translational Science, Perth, Western Australia.
| | - Julie Abimanyi-Ochom
- Deakin University, Deakin Health Economics, School of Health and Social Development, Geelong, Victoria, 3220, Australia; Deakin University, Institute for Health Transformation, Faculty of Health, Geelong, Victoria, 3220, Australia
| | - Ha Le
- Deakin University, Deakin Health Economics, School of Health and Social Development, Geelong, Victoria, 3220, Australia; Deakin University, Institute for Health Transformation, Faculty of Health, Geelong, Victoria, 3220, Australia
| | - Brian Long
- Neurosciences Unit, North Metropolitan Health Services Mental Health Public Health Dental Services, Perth, Western Australia
| | - Carolyn Orr
- Neurosciences Unit, North Metropolitan Health Services Mental Health Public Health Dental Services, Perth, Western Australia; Perron Institute for Neurological and Translational Science, Perth, Western Australia
| | - Long Khanh-Dao Le
- Health Economics Division, School of Public Health and Preventive Medicine, Monash University, Melbourne, Victoria, Australia
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Martinez Ramirez CE, Ruiz-Pérez G, Stollenwerk TM, Behlke C, Doherty A, Hillard CJ. Endocannabinoid signaling in the central nervous system. Glia 2023; 71:5-35. [PMID: 36308424 PMCID: PMC10167744 DOI: 10.1002/glia.24280] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/01/2022] [Revised: 09/02/2022] [Accepted: 09/29/2022] [Indexed: 11/07/2022]
Abstract
It is hard to overestimate the influence of the endocannabinoid signaling (ECS) system on central nervous system (CNS) function. In the 40 years since cannabinoids were found to trigger specific cell signaling cascades, studies of the ECS system continue to cause amazement, surprise, and confusion! CB1 cannabinoid receptors are expressed widely in the CNS and regulate cell-cell communication via effects on the release of both neurotransmitters and gliotransmitters. CB2 cannabinoid receptors are difficult to detect in the CNS but seem to "punch above their weight" as compounds targeting these receptors have significant effects on inflammatory state and behavior. Positive and negative allosteric modulators for both receptors have been identified and examined in preclinical studies. Concentrations of the endocannabinoid ligands, N-arachidonoylethanolamine and 2-arachidonoylglycerol (2-AG), are regulated by a combination of enzymatic synthesis and degradation and inhibitors of these processes are available and making their way into clinical trials. Importantly, ECS regulates many essential brain functions, including regulation of reward, anxiety, inflammation, motor control, and cellular development. While the field is on the cusp of preclinical discoveries providing impactful clinical and therapeutic insights into many CNS disorders, there is still much to be learned about this remarkable and versatile modulatory system.
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Affiliation(s)
- César E Martinez Ramirez
- Neuroscience Research Center and Department of Pharmacology and Toxicology, Medical College of Wisconsin, Milwaukee, Wisconsin, USA
| | - Gonzalo Ruiz-Pérez
- Neuroscience Research Center and Department of Pharmacology and Toxicology, Medical College of Wisconsin, Milwaukee, Wisconsin, USA
| | - Todd M Stollenwerk
- Neuroscience Research Center and Department of Pharmacology and Toxicology, Medical College of Wisconsin, Milwaukee, Wisconsin, USA
| | - Christina Behlke
- Neuroscience Research Center and Department of Pharmacology and Toxicology, Medical College of Wisconsin, Milwaukee, Wisconsin, USA
| | - Ashley Doherty
- Neuroscience Research Center and Department of Pharmacology and Toxicology, Medical College of Wisconsin, Milwaukee, Wisconsin, USA
| | - Cecilia J Hillard
- Neuroscience Research Center and Department of Pharmacology and Toxicology, Medical College of Wisconsin, Milwaukee, Wisconsin, USA
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5
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The monoacylglycerol lipase inhibitor, JZL184, has comparable effects to therapeutic hypothermia, attenuating global cerebral injury in a rat model of cardiac arrest. Biomed Pharmacother 2022; 156:113847. [DOI: 10.1016/j.biopha.2022.113847] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/16/2022] [Revised: 09/24/2022] [Accepted: 10/06/2022] [Indexed: 11/18/2022] Open
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Zhang LY, Kim AY, Cheer JF. Regulation of glutamate homeostasis in the nucleus accumbens by astrocytic CB1 receptors and its role in cocaine-motivated behaviors. ADDICTION NEUROSCIENCE 2022; 3:100022. [PMID: 36419922 PMCID: PMC9681119 DOI: 10.1016/j.addicn.2022.100022] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Indexed: 06/16/2023]
Abstract
Cannabinoid type 1 receptors (CB1Rs) orchestrate brain reward circuitry and are prevalent neurobiological targets for endocannabinoids and cannabis in the mammalian brain. Decades of histological and electrophysiological studies have established CB1R as presynaptic G-protein coupled receptors (GPCRs) that inhibit neurotransmitter release through retrograde signaling mechanisms. Recent seminal work demonstrates CB1R expression on astrocytes and the pivotal function of glial cells in endocannabinoid-mediated modulation of neuron-astrocyte signaling. Here, we review key facets of CB1R-mediated astroglia regulation of synaptic glutamate transmission in the nucleus accumbens with a specific emphasis on cocaine-directed behaviors.
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Affiliation(s)
- Lan-Yuan Zhang
- Department of Anatomy and Neurobiology, University of Maryland School of Medicine, Baltimore, MD, United States of America
| | - Andrew Y. Kim
- Department of Anatomy and Neurobiology, University of Maryland School of Medicine, Baltimore, MD, United States of America
| | - Joseph F. Cheer
- Department of Anatomy and Neurobiology, University of Maryland School of Medicine, Baltimore, MD, United States of America
- Program in Neuroscience, University of Maryland School of Medicine, Baltimore, MD, United States of America
- Department of Psychiatry, University of Maryland School of Medicine, Baltimore, MD, United States of America
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Kluger BM, Huang AP, Miyasaki JM. Cannabinoids in movement disorders. Parkinsonism Relat Disord 2022; 102:124-130. [PMID: 36038457 DOI: 10.1016/j.parkreldis.2022.08.014] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 07/16/2021] [Revised: 08/14/2022] [Accepted: 08/16/2022] [Indexed: 10/15/2022]
Abstract
INTRODUCTION On the basis of both scientific progress and popular lore, there is growing optimism in the therapeutic potential of cannabis (marijuana) and cannabinoid-based chemicals for movement disorders. There is also notable skepticism regarding the scientific basis for this therapeutic optimism and significant concerns regarding the safety and regulation of cannabinoid products, particularly those available without prescription. METHODS In recognition of the high interest and controversial nature of this subject, the meeting committee of the International Parkinson and Movement Disorders Society arranged for a talk on cannabis at the 2019 annual meeting's Controversies in Movement Disorders plenary session. This paper summarizes the highlights of this session. RESULTS The endocannabinoid system is strongly tied to motor function and dysfunction, with basic research suggesting several promising therapeutic targets related to cannabinoids for movement disorders. Clinical research on cannabinoids for motor and nonmotor symptoms in Parkinson's disease, Huntington's disease, Tourette's syndrome, dystonia, and other movement disorders to date are promising at best and inconclusive or negative at worst. Research in other populations suggest efficacy for common symptoms like pain. While social campaigns against recreational cannabinoid use focus on cognitive changes in adolescents, the long-term sequelae of regulated medical use in older adults with movement disorders is unknown. The overall risks of cannabinoids may be similar to other commonly used medications and include falls and apathy. CONCLUSION Further research is greatly needed to better understand the actual clinical benefits and long-term side effects of medical cannabis products for movement disorders indications and populations.
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Affiliation(s)
- Benzi M Kluger
- Departments of Neurology and Medicine, University of Rochester Medical Center, Rochester, NY, USA.
| | - Andrew P Huang
- Departments of Neurology and Medicine, University of Rochester Medical Center, Rochester, NY, USA
| | - Janis M Miyasaki
- Division of Neurology, Department of Medicine, University of Alberta, Edmonton, Alberta, Canada
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Nelson AB, Girasole AE, Lee HY, Ptáček LJ, Kreitzer AC. Striatal Indirect Pathway Dysfunction Underlies Motor Deficits in a Mouse Model of Paroxysmal Dyskinesia. J Neurosci 2022; 42:2835-2848. [PMID: 35165171 PMCID: PMC8973425 DOI: 10.1523/jneurosci.1614-20.2022] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/26/2020] [Revised: 01/20/2022] [Accepted: 02/07/2022] [Indexed: 11/21/2022] Open
Abstract
Abnormal involuntary movements, or dyskinesias, are seen in many neurologic diseases, including disorders where the brain appears grossly normal. This observation suggests that alterations in neural activity or connectivity may underlie dyskinesias. One influential model proposes that involuntary movements are driven by an imbalance in the activity of striatal direct and indirect pathway neurons (dMSNs and iMSNs, respectively). Indeed, in some animal models, there is evidence that dMSN hyperactivity contributes to dyskinesia. Given the many diseases associated with dyskinesia, it is unclear whether these findings generalize to all forms. Here, we used male and female mice in a mouse model of paroxysmal nonkinesigenic dyskinesia (PNKD) to assess whether involuntary movements are related to aberrant activity in the striatal direct and indirect pathways. In this model, as in the human disorder PNKD, animals experience dyskinetic attacks in response to caffeine or alcohol. Using optically identified striatal single-unit recordings in freely moving PNKD mice, we found a loss of iMSN firing during dyskinesia bouts. Further, chemogenetic inhibition of iMSNs triggered dyskinetic episodes in PNKD mice. Finally, we found that these decreases in iMSN firing are likely because of aberrant endocannabinoid-mediated suppression of glutamatergic inputs. These data show that striatal iMSN dysfunction contributes to the etiology of dyskinesia in PNKD, and suggest that indirect pathway hypoactivity may be a key mechanism for the generation of involuntary movements in other disorders.SIGNIFICANCE STATEMENT Involuntary movements, or dyskinesias, are part of many inherited and acquired neurologic syndromes. There are few effective treatments, most of which have significant side effects. Better understanding of which cells and patterns of activity cause dyskinetic movements might inform the development of new neuromodulatory treatments. In this study, we used a mouse model of an inherited human form of paroxysmal dyskinesia in combination with cell type-specific tools to monitor and manipulate striatal activity. We were able to narrow in on a specific group of neurons that causes dyskinesia in this model, and found alterations in a well-known form of plasticity in this cell type, endocannabinoid-dependent synaptic LTD. These findings point to new areas for therapeutic development.
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Affiliation(s)
- Alexandra B Nelson
- UCSF Neuroscience Graduate Program
- Department of Neurology, UCSF
- Kavli Institute for Fundamental Neuroscience
- UCSF Weill Institute for Neurosciences
| | - Allison E Girasole
- UCSF Neuroscience Graduate Program
- Department of Neurology, UCSF
- Kavli Institute for Fundamental Neuroscience
- UCSF Weill Institute for Neurosciences
| | | | - Louis J Ptáček
- UCSF Neuroscience Graduate Program
- Department of Neurology, UCSF
- Kavli Institute for Fundamental Neuroscience
- UCSF Weill Institute for Neurosciences
| | - Anatol C Kreitzer
- UCSF Neuroscience Graduate Program
- Department of Neurology, UCSF
- Department of Physiology, UCSF
- Kavli Institute for Fundamental Neuroscience
- UCSF Weill Institute for Neurosciences
- The Gladstone Institutes, San Francisco, California 94158
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Targeting Monoacylglycerol Lipase in Pursuit of Therapies for Neurological and Neurodegenerative Diseases. Molecules 2021; 26:molecules26185668. [PMID: 34577139 PMCID: PMC8468992 DOI: 10.3390/molecules26185668] [Citation(s) in RCA: 13] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/02/2021] [Revised: 09/11/2021] [Accepted: 09/15/2021] [Indexed: 11/17/2022] Open
Abstract
Neurological and neurodegenerative diseases are debilitating conditions, and frequently lack an effective treatment. Monoacylglycerol lipase (MAGL) is a key enzyme involved in the metabolism of 2-AG (2-arachidonoylglycerol), a neuroprotective endocannabinoid intimately linked to the generation of pro- and anti-inflammatory molecules. Consequently, synthesizing selective MAGL inhibitors has become a focus point in drug design and development. The purpose of this review was to summarize the diverse synthetic scaffolds of MAGL inhibitors concerning their potency, mechanisms of action and potential therapeutic applications, focusing on the results of studies published in the past five years. The main irreversible inhibitors identified were derivatives of hexafluoroisopropyl alcohol carbamates, glycol carbamates, azetidone triazole ureas and benzisothiazolinone, whereas the most promising reversible inhibitors were derivatives of salicylketoxime, piperidine, pyrrolidone and azetidinyl amides. We reviewed the results of in-depth chemical, mechanistic and computational studies on MAGL inhibitors, in addition to the results of in vitro findings concerning selectivity and potency of inhibitors, using the half maximal inhibitory concentration (IC50) as an indicator of their effect on MAGL. Further, for highlighting the potential usefulness of highly selective and effective inhibitors, we examined the preclinical in vivo reports regarding the promising therapeutic applications of MAGL pharmacological inhibition.
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Covey DP, Yocky AG. Endocannabinoid Modulation of Nucleus Accumbens Microcircuitry and Terminal Dopamine Release. Front Synaptic Neurosci 2021; 13:734975. [PMID: 34497503 PMCID: PMC8419321 DOI: 10.3389/fnsyn.2021.734975] [Citation(s) in RCA: 9] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/01/2021] [Accepted: 08/05/2021] [Indexed: 12/20/2022] Open
Abstract
The nucleus accumbens (NAc) is located in the ventromedial portion of the striatum and is vital to valence-based predictions and motivated action. The neural architecture of the NAc allows for complex interactions between various cell types that filter incoming and outgoing information. Dopamine (DA) input serves a crucial role in modulating NAc function, but the mechanisms that control terminal DA release and its effect on NAc neurons continues to be elucidated. The endocannabinoid (eCB) system has emerged as an important filter of neural circuitry within the NAc that locally shapes terminal DA release through various cell type- and site-specific actions. Here, we will discuss how eCB signaling modulates terminal DA release by shaping the activity patterns of NAc neurons and their afferent inputs. We then discuss recent technological advancements that are capable of dissecting how distinct cell types, their afferent projections, and local neuromodulators influence valence-based actions.
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Affiliation(s)
- Dan P Covey
- Department of Neuroscience, Lovelace Biomedical Research Institute, Albuquerque, NM, United States
| | - Alyssa G Yocky
- Department of Neuroscience, Lovelace Biomedical Research Institute, Albuquerque, NM, United States
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Yamin HG, Menkes-Caspi N, Stern EA, Cohen D. Age-Dependent Degradation of Locomotion Encoding in Huntington's Disease R6/2 Model Mice. J Huntingtons Dis 2021; 10:391-404. [PMID: 34420979 PMCID: PMC8609681 DOI: 10.3233/jhd-210492] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/15/2022]
Abstract
BACKGROUND Huntington's disease (HD) is an inherited fatal neurodegenerative disease, leading to neocortical and striatal atrophy. The commonly studied R6/2 HD transgenic mouse model displays progressive motor and cognitive deficits in parallel to major pathological changes in corticostriatal circuitry. OBJECTIVE To study how disease progression influences striatal encoding of movement. METHODS We chronically recorded neuronal activity in the dorsal striatum of R6/2 transgenic (Tg) mice and their age-matched nontransgenic littermate controls (WTs) during novel environment exposure, a paradigm which engages locomotion to explore the novel environment. RESULTS Exploratory locomotion degraded with age in Tg mice as compared to WTs. We encountered fewer putative medium spiny neurons (MSNs)-striatal projection neurons, and more inhibitory interneurons-putative fast spiking interneurons (FSIs) in Tg mice as compared to WTs. MSNs from Tg mice fired less spikes in bursts without changing their firing rate, while FSIs from these mice had a lower firing rate and more of them were task-responsive as compared to WTs. Additionally, MSNs from Tg mice displayed a reduced ability to encode locomotion across age groups, likely associated with their low prevalence in Tg mice, whereas the encoding of locomotion by FSIs from Tg mice was substantially reduced solely in old Tg mice as compared to WTs. CONCLUSION Our findings reveal an age-dependent decay in striatal information processing in transgenic mice. We propose that the ability of FSIs to compensate for the loss of MSNs by processes of recruitment and enhanced task-responsiveness diminishes with disease progression, possibly manifested in the displayed age-dependent degradation of exploratory locomotion.
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Affiliation(s)
- Hagar G Yamin
- The Leslie and Susan Gonda Multidisciplinary Brain Research Center, Bar-Ilan University, Ramat-Gan, Israel
| | - Noa Menkes-Caspi
- The Leslie and Susan Gonda Multidisciplinary Brain Research Center, Bar-Ilan University, Ramat-Gan, Israel
| | - Edward A Stern
- The Leslie and Susan Gonda Multidisciplinary Brain Research Center, Bar-Ilan University, Ramat-Gan, Israel.,MassGeneral Institute for Neurodegenerative Disease, Department of Neurology, Massachusetts General Hospital, Charlestown, MA, USA
| | - Dana Cohen
- The Leslie and Susan Gonda Multidisciplinary Brain Research Center, Bar-Ilan University, Ramat-Gan, Israel
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Covey DP, Hernandez E, Luján MÁ, Cheer JF. Chronic Augmentation of Endocannabinoid Levels Persistently Increases Dopaminergic Encoding of Reward Cost and Motivation. J Neurosci 2021; 41:6946-6953. [PMID: 34230105 PMCID: PMC8360683 DOI: 10.1523/jneurosci.0285-21.2021] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/05/2021] [Revised: 06/16/2021] [Accepted: 06/21/2021] [Indexed: 11/21/2022] Open
Abstract
Motivational deficits characterized by an unwillingness to overcome effortful costs are a common feature of neuropsychiatric and neurologic disorders that are insufficiently understood and treated. Dopamine (DA) signaling in the nucleus accumbens (NAc) facilitates goal-seeking, but how NAc DA release encodes motivationally salient stimuli to influence effortful investment is not clear. Using fast-scan cyclic voltammetry in male and female mice, we find that NAc DA release diametrically responds to cues signaling increasing cost of reward, while DA release to the reward itself is unaffected by its cost. Because endocannabinoid (eCB) signaling facilitates goal seeking and NAc DA release, we further investigated whether repeated augmentation of the eCB 2-arachidonoylglycerol with a low dose of a monoacylglycerol lipase (MAGL) inhibitor facilitates motivation and DA signaling without the development of tolerance. We find that chronic MAGL treatment stably facilitates goal seeking and DA encoding of prior reward cost, providing critical insight into the neurobiological mechanisms of a viable treatment for motivational deficits.SIGNIFICANCE STATEMENT Decades of work has established a fundamental role for dopamine neurotransmission in motivated behavior and cue-reward learning, but how dopaminergic encoding of cues associates with motivated action has remained unclear. Specifically, how dopamine neurons signal future and prior reward cost, and whether this can be modified to influence motivational set points is not known. The current study provides important insight into how dopamine neurons encode motivationally relevant stimuli to influence goal-directed action and supports cannabinoid-based therapies for treatment of motivational disorders.
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Affiliation(s)
- Dan P Covey
- Department of Neuroscience, Lovelace Biomedical Research Institute, Albuquerque, New Mexico 87108
| | - Edith Hernandez
- Medical Scientist Training Program (MD/PhD), University of Minnesota Medical School, Minneapolis, Minnesota 55455
| | - Miguel Á Luján
- Department of Anatomy and Neurobiology, University of Maryland School of Medicine, Baltimore, Maryland 21201
| | - Joseph F Cheer
- Department of Anatomy and Neurobiology, University of Maryland School of Medicine, Baltimore, Maryland 21201
- Department of Psychiatry, University of Maryland School of Medicine, Baltimore, Maryland 21201
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Engi SA, Beebe EJ, Ayvazian VM, Cruz FC, Cheer JF, Wenzel JM, Zlebnik NE. Cocaine-induced increases in motivation require 2-arachidonoylglycerol mobilization and CB1 receptor activation in the ventral tegmental area. Neuropharmacology 2021; 193:108625. [PMID: 34058192 PMCID: PMC8312311 DOI: 10.1016/j.neuropharm.2021.108625] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/31/2021] [Revised: 05/13/2021] [Accepted: 05/24/2021] [Indexed: 11/15/2022]
Abstract
A wide body of evidence supports an integral role for mesolimbic dopamine (DA) in motivated behavior. In brief, drugs that increase DA in mesolimbic terminal regions, like cocaine, enhance motivation, while drugs that decrease DA concentration reduce motivation. Data from our laboratory and others shows that phasic activation of mesolimbic DA requires signaling at cannabinoid type-1 (CB1) receptors in the ventral tegmental area (VTA), and systemic delivery of CB1 receptor antagonists reduces DA cell activity and attenuates motivated behaviors. Recent findings demonstrate that cocaine mobilizes the endocannabinoid 2-arachidonoylglycerol (2-AG) in the VTA to cause phasic activation of DA neurons and terminal DA release. It remains unclear, however, if cocaine-induced midbrain 2-AG signaling contributes to the motivation-enhancing effects of cocaine. To examine this, we trained male and female rats on a progressive ratio (PR) task for a food reinforcer. Each rat underwent a series of tests in which they were pretreated with cocaine alone or in combination with systemic or intra-VTA administration of the CB1 receptor antagonist rimonabant or the 2-AG synthesis inhibitor tetrahydrolipstatin (THL). Cocaine increased motivation, measured by augmented PR breakpoints, while rimonabant dose-dependently decreased motivation. Importantly, intra-VTA administration of rimonabant or THL, at doses that did not decrease breakpoints on their own, blocked systemic cocaine administration from increasing breakpoints in male and female rats. These data suggest that cocaine-induced increases in motivation require 2-AG signaling at CB1 receptors in the VTA and may provide critical insight into cannabinoid-based pharmacotherapeutic targets for the successful treatment of substance abuse.
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Affiliation(s)
- Sheila A Engi
- Dept. of Anatomy and Neurobiology, University of Maryland School of Medicine, Baltimore, MD, USA; Dept. of Pharmacology, Universidade Federal de São Paulo - UNIFESP, São Paulo, SP, Brazil
| | - Erin J Beebe
- Dept. of Anatomy and Neurobiology, University of Maryland School of Medicine, Baltimore, MD, USA
| | - Victoria M Ayvazian
- Dept. of Anatomy and Neurobiology, University of Maryland School of Medicine, Baltimore, MD, USA
| | - Fabio C Cruz
- Dept. of Pharmacology, Universidade Federal de São Paulo - UNIFESP, São Paulo, SP, Brazil
| | - Joseph F Cheer
- Dept. of Anatomy and Neurobiology, University of Maryland School of Medicine, Baltimore, MD, USA; Dept. of Psychiatry, University of Maryland School of Medicine, Baltimore, MD, USA
| | - Jennifer M Wenzel
- Dept. of Anatomy and Neurobiology, University of Maryland School of Medicine, Baltimore, MD, USA.
| | - Natalie E Zlebnik
- Dept. of Anatomy and Neurobiology, University of Maryland School of Medicine, Baltimore, MD, USA.
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14
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Hurel I, Muguruza C, Redon B, Marsicano G, Chaouloff F. Cannabis and exercise: Effects of Δ 9-tetrahydrocannabinol on preference and motivation for wheel-running in mice. Prog Neuropsychopharmacol Biol Psychiatry 2021; 105:110117. [PMID: 32971218 DOI: 10.1016/j.pnpbp.2020.110117] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 08/04/2020] [Revised: 09/11/2020] [Accepted: 09/20/2020] [Indexed: 11/27/2022]
Abstract
Recent surveys have revealed close links between cannabis and exercise. Specifically, cannabis usage before and/or after exercise is an increasingly common habit primarily aimed at boosting exercise pleasure, motivation, and performance whilst facilitating post-exercise recovery. However, whether these beliefs reflect the true impact of cannabis on these aspects of exercise is unknown. This study has thus examined the effects of cannabis' main psychoactive ingredient, namely Δ9-tetrahydrocannabinol (THC), on (i) mouse wheel-running preference and performance and (ii) running motivation and seeking behaviour. Wheel-running preference and performance were investigated using a T-maze with free and locked wheels located at the extremity of either arm. Running motivation and seeking were assessed by a cued-running operant task wherein wheel-running was conditioned by nose poking. Moreover, because THC targets cannabinoid type 1 (CB1) receptors, i.e. receptors previously documented to control running motivation, this study also assessed the role of these receptors in running preference, performance, and craving-like behaviour. Whilst acute blockade or genetic deletion of CB1 receptors decreased running preference and performance in the T-maze, THC proved ineffective on either variable. The failure of THC to affect running variables in the T-maze extended to running motivation, as assessed by cued-running under a progressive ratio (PR) reinforcement schedule. This ineffectiveness of THC was not related to the treatment protocol because it successfully increased motivation for palatable food. Although craving-like behaviour, as indexed by a cue-induced reinstatement of running seeking, was found to depend on CB1 receptors, THC again proved ineffective. Neither running motivation nor running seeking were affected when CB1 receptors were further stimulated by increasing the levels of the endocannabinoid 2-arachidonoylglycerol. These results, which suggest that the drive for running is insensitive to the acute stimulation of CB1 receptors, raise the hypothesis that cannabis is devoid of effect on exercise motivation. Future investigation using chronic administration of THC, with and without other cannabis ingredients (e.g. cannabidiol), is however required before conclusions can be drawn.
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Affiliation(s)
- Imane Hurel
- Endocannabinoids and NeuroAdaptation, NeuroCentre INSERM U1215, 33077 Bordeaux, France; Université de Bordeaux, 33077 Bordeaux, France
| | - Carolina Muguruza
- Endocannabinoids and NeuroAdaptation, NeuroCentre INSERM U1215, 33077 Bordeaux, France; Université de Bordeaux, 33077 Bordeaux, France; Department of Pharmacology, University of the Basque Country UPV/EHU, Leioa, Bizkaia, Spain; Centro de Investigación Biomédica en Red de Salud Mental, CIBERSAM, Spain
| | - Bastien Redon
- Endocannabinoids and NeuroAdaptation, NeuroCentre INSERM U1215, 33077 Bordeaux, France; Université de Bordeaux, 33077 Bordeaux, France
| | - Giovanni Marsicano
- Endocannabinoids and NeuroAdaptation, NeuroCentre INSERM U1215, 33077 Bordeaux, France; Université de Bordeaux, 33077 Bordeaux, France
| | - Francis Chaouloff
- Endocannabinoids and NeuroAdaptation, NeuroCentre INSERM U1215, 33077 Bordeaux, France; Université de Bordeaux, 33077 Bordeaux, France.
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15
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Everett TJ, Gomez DM, Hamilton LR, Oleson EB. Endocannabinoid modulation of dopamine release during reward seeking, interval timing, and avoidance. Prog Neuropsychopharmacol Biol Psychiatry 2021; 104:110031. [PMID: 32663486 DOI: 10.1016/j.pnpbp.2020.110031] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 05/02/2020] [Revised: 06/15/2020] [Accepted: 06/28/2020] [Indexed: 01/02/2023]
Abstract
Endocannabinoids (eCBs) are neuromodulators that influence a wide range of neural systems and behaviors. In the current review, we describe our recent research showing how eCBs, particularly 2-arachidonoylglycerol (2-AG), concurrently shape mesolimbic dopamine (DA) release and associated behavior. We will restrict our discussion by emphasizing three distinct behaviors: reward seeking, interval timing, and active avoidance. During reward seeking we find that 2-AG is necessary to observe cue-evoked DA release events that are thought to represent the value of a rewarding outcome. We then describe data showing that 2-AG modulates unique patterns of DA release and behavior observed under conditions of periodic reinforcement. These data are discussed within the context of interval timing and adjunctive behavior. eCB modulation of DA release is also implicated in defensive behavior, including the avoidance of harm. As in reward seeking, our data suggest that the concentration of DA that is evoked by a warning signal can represent the value of an avoidance outcome. And, disrupting eCB signaling concomitantly reduces the concentration of the avoidance value signal and active avoidance. Disruptions in reward seeking, interval timing, and defensive behavior are commonly observed in a variety of movement disorders (e.g., Parkinson's and Huntington's disease) and disorders of motivation (e.g., addiction). We believe our data on eCB-DA interactions have implications for the development of novel pharmacotherapies to treat these disorders. Thus, we conclude by discussing how eCB pharmacology might be harnessed to treat disorders of movement and motivation.
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Affiliation(s)
| | - Devan M Gomez
- Psychology Department, University of Colorado Denver, USA; Department of Biomedical Sciences, Marquette University, USA
| | | | - Erik B Oleson
- Psychology Department, University of Colorado Denver, USA; Integrative Biology Department, University of Colorado Denver, USA.
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16
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Bononi G, Poli G, Rizzolio F, Tuccinardi T, Macchia M, Minutolo F, Granchi C. An updated patent review of monoacylglycerol lipase (MAGL) inhibitors (2018-present). Expert Opin Ther Pat 2020; 31:153-168. [PMID: 33085920 DOI: 10.1080/13543776.2021.1841166] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/13/2022]
Abstract
INTRODUCTION Monoacylglycerol lipase (MAGL) belongs to the endocannabinoid system and is responsible for the inactivation of endocannabinoid 2-arachidonoylglycerol. Importantly, it was found that MAGL degradation of lipids in cancer cells enhances the availability of free fatty acids for new cellular membrane formation and pro-oncogenic lipid modulators. The multifaceted role of MAGL has greatly stimulated the search for MAGL inhibitors, which could be effective to treat diseases, such as inflammation, neurodegeneration and cancer. AREAS COVERED This review covers patents published since 2018 up to now, concerning new MAGL inhibitors and their potential therapeutic applications. EXPERT OPINION In the years 2018-2020, several well-known chemical scaffolds of MAGL inhibitors have been further optimized and developed and some new chemical classes have also been identified as MAGL inhibitors. Moreover, an increasing number of scientific publications covering MAGL inhibitors is focused on MAGL-specific positron emission tomography (PET) ligands. The numerous efforts of pharmaceutical companies and academic research groups finalized to find new potent MAGL inhibitors confirm that this research area is rapidly growing. Nevertheless, most of the patented compounds still belong to the large group of irreversible MAGL inhibitors, highlighting that the development of reversible MAGL inhibitors is still an unmet pharmaceutical need.
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Affiliation(s)
- Giulia Bononi
- Department of Pharmacy, University of Pisa , Pisa, Italy
| | - Giulio Poli
- Department of Pharmacy, University of Pisa , Pisa, Italy
| | - Flavio Rizzolio
- Pathology Unit, Centro Di Riferimento Oncologico Di Aviano (CRO) IRCCS , Aviano, Italy.,Department of Molecular Science and Nanosystems, Ca' Foscari University , Venezia, Italy
| | | | - Marco Macchia
- Department of Pharmacy, University of Pisa , Pisa, Italy
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17
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Accumbal Dopamine Release Tracks the Expectation of Dopamine Neuron-Mediated Reinforcement. Cell Rep 2020; 27:481-490.e3. [PMID: 30970251 DOI: 10.1016/j.celrep.2019.03.055] [Citation(s) in RCA: 17] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/24/2018] [Revised: 11/02/2018] [Accepted: 03/13/2019] [Indexed: 12/27/2022] Open
Abstract
Dopamine (DA) transmission in the nucleus accumbens (NAc) facilitates cue-reward associations and appetitive action. Reward-related accumbal DA release dynamics are traditionally ascribed to ventral tegmental area (VTA) DA neurons. Activation of VTA to NAc DA signaling is thought to reinforce action and transfer reward-related information to predictive cues, allowing cues to guide behavior and elicit dopaminergic activity. Here, we use optogenetics to control DA neuron activity and voltammetry to simultaneously record accumbal DA release in order to quantify how reinforcer-evoked dopaminergic activity shapes conditioned mesolimbic DA transmission. We find that cues predicting access to DA neuron self-stimulation elicit conditioned responding and NAc DA release. However, cue-evoked DA release does not reflect the cost or magnitude of DA neuron activation. Accordingly, conditioned accumbal DA release selectively tracks the expected availability of DA-neuron-mediated reinforcement. This work provides insight into how mesolimbic DA transmission drives and encodes appetitive action.
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18
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Stasiulewicz A, Znajdek K, Grudzień M, Pawiński T, Sulkowska JI. A Guide to Targeting the Endocannabinoid System in Drug Design. Int J Mol Sci 2020; 21:ijms21082778. [PMID: 32316328 PMCID: PMC7216112 DOI: 10.3390/ijms21082778] [Citation(s) in RCA: 70] [Impact Index Per Article: 17.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/16/2020] [Revised: 04/07/2020] [Accepted: 04/14/2020] [Indexed: 12/11/2022] Open
Abstract
The endocannabinoid system (ECS) is one of the most crucial systems in the human organism, exhibiting multi-purpose regulatory character. It is engaged in a vast array of physiological processes, including nociception, mood regulation, cognitive functions, neurogenesis and neuroprotection, appetite, lipid metabolism, as well as cell growth and proliferation. Thus, ECS proteins, including cannabinoid receptors and their endogenous ligands’ synthesizing and degrading enzymes, are promising therapeutic targets. Their modulation has been employed in or extensively studied as a treatment of multiple diseases. However, due to a complex nature of ECS and its crosstalk with other biological systems, the development of novel drugs turned out to be a challenging task. In this review, we summarize potential therapeutic applications for ECS-targeting drugs, especially focusing on promising synthetic compounds and preclinical studies. We put emphasis on modulation of specific proteins of ECS in different pathophysiological areas. In addition, we stress possible difficulties and risks and highlight proposed solutions. By presenting this review, we point out information pivotal in the spotlight of ECS-targeting drug design, as well as provide an overview of the current state of knowledge on ECS-related pharmacodynamics and show possible directions for needed research.
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Affiliation(s)
- Adam Stasiulewicz
- Department of Drug Chemistry, Faculty of Pharmacy, Medical University of Warsaw, Banacha 1, 02-097 Warsaw, Poland; (M.G.); (T.P.)
- Interdisciplinary Laboratory of Biological Systems Modelling, Centre of New Technologies, University of Warsaw, Banacha 2c, 02-097 Warsaw, Poland;
- Correspondence: (A.S.); (J.I.S.)
| | - Katarzyna Znajdek
- Interdisciplinary Laboratory of Biological Systems Modelling, Centre of New Technologies, University of Warsaw, Banacha 2c, 02-097 Warsaw, Poland;
- Faculty of Pharmacy, Medical University of Warsaw, Banacha 1, 02-097 Warsaw, Poland
| | - Monika Grudzień
- Department of Drug Chemistry, Faculty of Pharmacy, Medical University of Warsaw, Banacha 1, 02-097 Warsaw, Poland; (M.G.); (T.P.)
| | - Tomasz Pawiński
- Department of Drug Chemistry, Faculty of Pharmacy, Medical University of Warsaw, Banacha 1, 02-097 Warsaw, Poland; (M.G.); (T.P.)
| | - Joanna I. Sulkowska
- Interdisciplinary Laboratory of Biological Systems Modelling, Centre of New Technologies, University of Warsaw, Banacha 2c, 02-097 Warsaw, Poland;
- Faculty of Chemistry, University of Warsaw, Pasteura 1, 02-093 Warsaw, Poland
- Materials and Process Simulation Center, California Institute of Technology, Pasadena, CA 91125, USA
- Correspondence: (A.S.); (J.I.S.)
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19
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Blumenstock S, Dudanova I. Cortical and Striatal Circuits in Huntington's Disease. Front Neurosci 2020; 14:82. [PMID: 32116525 PMCID: PMC7025546 DOI: 10.3389/fnins.2020.00082] [Citation(s) in RCA: 51] [Impact Index Per Article: 12.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/15/2019] [Accepted: 01/21/2020] [Indexed: 12/28/2022] Open
Abstract
Huntington's disease (HD) is a hereditary neurodegenerative disorder that typically manifests in midlife with motor, cognitive, and/or psychiatric symptoms. The disease is caused by a CAG triplet expansion in exon 1 of the huntingtin gene and leads to a severe neurodegeneration in the striatum and cortex. Classical electrophysiological studies in genetic HD mouse models provided important insights into the disbalance of excitatory, inhibitory and neuromodulatory inputs, as well as progressive disconnection between the cortex and striatum. However, the involvement of local cortical and striatal microcircuits still remains largely unexplored. Here we review the progress in understanding HD-related impairments in the cortical and basal ganglia circuits, and outline new opportunities that have opened with the development of modern circuit analysis methods. In particular, in vivo imaging studies in mouse HD models have demonstrated early structural and functional disturbances within the cortical network, and optogenetic manipulations of striatal cell types have started uncovering the causal roles of certain neuronal populations in disease pathogenesis. In addition, the important contribution of astrocytes to HD-related circuit defects has recently been recognized. In parallel, unbiased systems biology studies are providing insights into the possible molecular underpinnings of these functional defects at the level of synaptic signaling and neurotransmitter metabolism. With these approaches, we can now reach a deeper understanding of circuit-based HD mechanisms, which will be crucial for the development of effective and targeted therapeutic strategies.
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Affiliation(s)
- Sonja Blumenstock
- Department of Molecules – Signaling – Development, Max Planck Institute of Neurobiology, Martinsried, Germany
- Molecular Neurodegeneration Group, Max Planck Institute of Neurobiology, Martinsried, Germany
| | - Irina Dudanova
- Molecular Neurodegeneration Group, Max Planck Institute of Neurobiology, Martinsried, Germany
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20
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Grimsey NL, Savinainen JR, Attili B, Ahamed M. Regulating membrane lipid levels at the synapse by small-molecule inhibitors of monoacylglycerol lipase: new developments in therapeutic and PET imaging applications. Drug Discov Today 2019; 25:330-343. [PMID: 31622747 DOI: 10.1016/j.drudis.2019.10.004] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/16/2019] [Revised: 09/17/2019] [Accepted: 10/09/2019] [Indexed: 12/14/2022]
Abstract
Monoacylglycerol lipase (MAGL) is a major endocannabinoid hydrolyzing enzyme and can be regulated to control endogenous lipid levels in the brain. This review highlights the pharmacological roles and in vivo PET imaging of MAGL in brain.
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Affiliation(s)
- Natasha L Grimsey
- Department of Pharmacology and Clinical Pharmacology, and Centre for Brain Research, Faculty of Medical and Health Sciences, University of Auckland, New Zealand
| | - Juha R Savinainen
- Institute of Biomedicine, Faculty of Health Sciences, The University of Eastern Finland, Finland
| | - Bala Attili
- Department of Radiology, The University of Cambridge, UK
| | - Muneer Ahamed
- ARC Centre for Innovation in Biomedical Imaging Technology, Centre for Advanced Imaging, The University of Queensland, Australia.
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21
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Nam H, Chandra R, Francis TC, Dias C, Cheer JF, Lobo MK. Reduced nucleus accumbens enkephalins underlie vulnerability to social defeat stress. Neuropsychopharmacology 2019; 44:1876-1885. [PMID: 31132785 PMCID: PMC6784997 DOI: 10.1038/s41386-019-0422-8] [Citation(s) in RCA: 29] [Impact Index Per Article: 5.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 01/22/2019] [Revised: 04/24/2019] [Accepted: 05/15/2019] [Indexed: 02/07/2023]
Abstract
Enkephalins, endogenous ligands for delta opioid receptors (DORs), are highly enriched in the nucleus accumbens (NAc). They are implicated in depression but their role in the NAc, a critical brain region for motivated behavior, is not fully investigated. To provide insight into enkephalin function we used a chronic social defeat stress paradigm, where animals are either categorized as susceptible or resilient to stress based on their performance in a social interaction test. Compared to controls, susceptible animals showed reduced enkephalin levels in the NAc. Such decrease in enkephalin levels is not due to a change in mRNA of its precursor protein, proenkephalin, in susceptible mice but is consistent with increased mRNA levels of enkephalinases in the NAc of susceptible animals. Systemic administration of enkephalinase inhibitors or NAc infusion of the DOR agonist, SNC80, caused a resilient outcome to CSDS. Both treatments increased phosphorylation of ERK, which was downregulated by social defeat stress. To further validate these results, we also used Q175 knock-in mice, an animal model of Huntington's disease in which enkephalin levels are reduced in striatum and comorbidity with mood disorders is common. Consistent with data in wild-type mice, Q175 animals showed reduced enkephalin levels in the NAc and enhanced susceptibility to a social defeat stress. Overall, our data implicate that depression-like behavior induced by social defeat stress arises from disrupted DOR signaling resulting from lowered levels of enkephalins, which is partly mediated through elevated expression of enkephalinases.
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Affiliation(s)
- Hyungwoo Nam
- Department of Anatomy and Neurobiology, University of Maryland School of Medicine, Baltimore, MD, USA
| | - Ramesh Chandra
- Department of Anatomy and Neurobiology, University of Maryland School of Medicine, Baltimore, MD, USA
| | - T Chase Francis
- Department of Anatomy and Neurobiology, University of Maryland School of Medicine, Baltimore, MD, USA
- Synaptic Plasticity Section, National Institute on Drug Abuse Intramural Research Program, Baltimore, MD, USA
| | - Caroline Dias
- Department of Neuroscience, ICAHN School of Medicine at Mount Sinai, New York, NY, USA
- Division of Developmental Medicine, Boston Children's Hospital, Boston, MA, USA
| | - Joseph F Cheer
- Department of Anatomy and Neurobiology, University of Maryland School of Medicine, Baltimore, MD, USA
| | - Mary Kay Lobo
- Department of Anatomy and Neurobiology, University of Maryland School of Medicine, Baltimore, MD, USA.
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22
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Heath CJ, O'Callaghan C, Mason SL, Phillips BU, Saksida LM, Robbins TW, Barker RA, Bussey TJ, Sahakian BJ. A Touchscreen Motivation Assessment Evaluated in Huntington's Disease Patients and R6/1 Model Mice. Front Neurol 2019; 10:858. [PMID: 31447770 PMCID: PMC6696591 DOI: 10.3389/fneur.2019.00858] [Citation(s) in RCA: 17] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/21/2019] [Accepted: 07/24/2019] [Indexed: 12/18/2022] Open
Abstract
Apathy is pervasive across many neuropsychiatric disorders but is poorly characterized mechanistically, so targeted therapeutic interventions remain elusive. A key impediment has been the lack of validated assessment tools to facilitate translation of promising findings between preclinical disease models and patients. Apathy is a common symptom in Huntington's disease. Due to its established genetic basis and the availability of defined animal models, this disease offers a robust translational framework for linking motivated behavior with underlying neurobiology and an ideal context in which to evaluate a quantitative, translational apathy assessment method. In this study we therefore aimed to demonstrate the validity of using touchscreen-delivered progressive ratio tasks to mirror apathy assessment in Huntington's disease patients and a representative mouse model. To do this we evaluated Huntington's disease patients (n = 23) and age-matched healthy controls (n = 20), and male R6/1 mice (n = 23) and wildtype controls (n = 29) for apathy-like behavior using touchscreen-delivered progressive ratio tasks. The primary outcome measure of the assessment was breakpoint, defined as the highest number of touchscreen responses emitted before task engagement ceased. Patients and R6/1 mice were both found to exhibit significantly reduced breakpoints relative to their respective control groups, consistent with apathy-like behavior. This performance was also not associated with motoric differences in either species. These data demonstrate the utility of touchscreen-delivered progressive ratio tasks in detecting clinically relevant motivational deficits in Huntington's disease. This approach may offer a platform from which clinically relevant mechanistic insights concerning motivation symptoms can be derived and provide an effective route for translation of promising preclinical findings into viable therapeutic interventions.
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Affiliation(s)
- Christopher J. Heath
- Department of Psychology, Behavioural and Clinical Neuroscience Institute, University of Cambridge, Cambridge, United Kingdom
- School of Life, Health and Chemical Sciences, The Open University, Milton Keynes, United Kingdom
| | - Claire O'Callaghan
- Department of Psychology, Behavioural and Clinical Neuroscience Institute, University of Cambridge, Cambridge, United Kingdom
- Brain and Mind Centre, University of Sydney, Sydney, NSW, Australia
| | - Sarah L. Mason
- John van Geest Centre for Brain Repair, Addenbrooke's Hospital, University of Cambridge School of Clinical Medicine, Cambridge, United Kingdom
| | - Benjamin U. Phillips
- Department of Psychology, Behavioural and Clinical Neuroscience Institute, University of Cambridge, Cambridge, United Kingdom
| | - Lisa M. Saksida
- Department of Psychology, Behavioural and Clinical Neuroscience Institute, University of Cambridge, Cambridge, United Kingdom
- Department of Physiology and Pharmacology, Schulich School of Medicine and Dentistry, University of Western Ontario, London, ON, Canada
| | - Trevor W. Robbins
- Department of Psychology, Behavioural and Clinical Neuroscience Institute, University of Cambridge, Cambridge, United Kingdom
| | - Roger A. Barker
- John van Geest Centre for Brain Repair, Addenbrooke's Hospital, University of Cambridge School of Clinical Medicine, Cambridge, United Kingdom
| | - Timothy J. Bussey
- Department of Psychology, Behavioural and Clinical Neuroscience Institute, University of Cambridge, Cambridge, United Kingdom
- Department of Physiology and Pharmacology, Schulich School of Medicine and Dentistry, University of Western Ontario, London, ON, Canada
| | - Barbara J. Sahakian
- Department of Psychiatry, University of Cambridge School of Clinical Medicine, Cambridge, United Kingdom
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23
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Smith‐Dijak AI, Sepers MD, Raymond LA. Alterations in synaptic function and plasticity in Huntington disease. J Neurochem 2019; 150:346-365. [DOI: 10.1111/jnc.14723] [Citation(s) in RCA: 64] [Impact Index Per Article: 12.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/23/2018] [Revised: 03/28/2019] [Accepted: 05/08/2019] [Indexed: 12/27/2022]
Affiliation(s)
- Amy I. Smith‐Dijak
- Graduate Program in Neuroscience the University of British Columbia Vancouver British Columbia Canada
- Department of Psychiatry and Djavad Mowafaghian Centre for Brain Health the University of British Columbia Vancouver British Columbia Canada
| | - Marja D. Sepers
- Department of Psychiatry and Djavad Mowafaghian Centre for Brain Health the University of British Columbia Vancouver British Columbia Canada
| | - Lynn A. Raymond
- Department of Psychiatry and Djavad Mowafaghian Centre for Brain Health the University of British Columbia Vancouver British Columbia Canada
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