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Zheng X, Ehrlich B, Finlay D, Glass M. No Evidence for Endocannabinoid-Induced G Protein Subtype Selectivity at Human and Rodent Cannabinoid CB 1 Receptors. Cannabis Cannabinoid Res 2024. [PMID: 39373143 DOI: 10.1089/can.2024.0133] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/08/2024] Open
Abstract
Introduction: The endocannabinoid system (ECS) is a widespread neurotransmitter system. A key characteristic of the ECS is that there are multiple endogenous ligands (endocannabinoids). Of these, the most extensively studied are arachidonoyl ethanolamide (AEA) and 2-arachidonoyl-glycerol (2-AG), both act as agonists at the cannabinoid CB1 receptor. In humans, three CB1 variants have been identified: hCB1, considered the most abundant G protein-coupled receptor in the brain, alongside the less abundant and studied variants, hCB1a and hCB1b. CB1 exhibits a preference for coupling with inhibitory Gi/o proteins, although its interactions with specific members of the Gi/o family remain poorly characterized. This study aimed to compare the AEA and 2-AG-induced activation of various G protein subtypes at CB1. Furthermore, we compared the response of human CB1 (hCB1, hCB1a, hCB1b) and explored species differences by examining rodent receptors (mCB1, rCB1). Materials and Methods: Activation of individual G protein subtypes in HEK293 cells transiently expressing CB1 was measured with G protein dissociation assay utilizing TRUPATH biosensors. The performance of the TRUPATH biosensors was evaluated using Z-factor analysis. Pathway potencies and efficacies were analyzed using the operational analysis of bias to determine G protein subtype selectivity for AEA and 2-AG. Results: Initial screening of TRUPATH biosensors performance revealed variable sensitivities within our system. Based on the biosensor performance, the G protein subtypes pursued for further characterization were Gi1, Gi3, GoA, GoB, GZ, G12, and G13. Across all pathways, AEA demonstrated partial agonism, whereas 2-AG exhibited full or high-efficacy agonism. Notably, we provide direct evidence that the hCB1 receptor couples to G12 and G13 proteins. Our findings do not indicate any evidence of G protein subtype selectivity. Similar observations were made across the human receptor variants (hCB1, hCB1a, hCB1b), as well as at mCB1 and rCB1. Discussion: There was no evidence suggesting G protein subtype selectivity for AEA and 2-AG at CB1, and this finding remained consistent across human receptor variants and different species.
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Affiliation(s)
- Xiaoxi Zheng
- Department of Pharmacology and Toxicology, School of Biomedical Sciences, University of Otago, Dunedin, New Zealand
| | - Beth Ehrlich
- Department of Pharmacology and Toxicology, School of Biomedical Sciences, University of Otago, Dunedin, New Zealand
| | - David Finlay
- Department of Pharmacology and Toxicology, School of Biomedical Sciences, University of Otago, Dunedin, New Zealand
| | - Michelle Glass
- Department of Pharmacology and Toxicology, School of Biomedical Sciences, University of Otago, Dunedin, New Zealand
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Šanjug J, Kuna K, Goldštajn MŠ, Dunkić LF, Carek A, Negovetić Vranić D. Relationship between COMT Gene Polymorphism, Anxiety, and Pain Perception during Labour. J Clin Med 2023; 12:6298. [PMID: 37834942 PMCID: PMC10573766 DOI: 10.3390/jcm12196298] [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: 08/23/2023] [Revised: 09/22/2023] [Accepted: 09/26/2023] [Indexed: 10/15/2023] Open
Abstract
BACKGROUND The COMT gene polymorphism is associated with neurological and psychiatric disorders and pain perception. The present study investigates the existence of anxiety and pain perception in relation to the COMT (catechol-O-methyltransferase) gene polymorphism in labouring women (during "natural" childbirth) with or without inhaled analgesia. METHODS A total of 181 women who chose vaginal birth were enrolled in this study. To present the difference in pain perception, the parturients were divided into one group (n = 90) that chose labour analgesia with inhaled nitrous oxide (50% nitrous oxide and 50% oxygen) and one group (n = 91) without analgesia. The blood samples were taken during the pregnancy as a part of routine pregnancy controls in the hospital. The COMT gene polymorphism was detected with the PCR technique. The pain perception of parturients was self-evaluated two times according to the VAS (Visual Analogue Scale), and anxiety as a personality trait was determined with the STAI-T (State Trait Anxiety Inventory). Pain perception as well as anxiety were compared according to COMT genotypes. RESULTS In the 181 pregnant women, there were 40 women (22%) of wild homozygotes (GG) of COMT, 95 women (53%) of mutant heterozygotes (GA), and 46 women (25%) of mutant homozygotes (AA). A negative association of pain perception with the GA (mutant heterozygote) polymorphism of the COMT gene versus the wild-type (GG polymorphism) was observed. The GA polymorphism of the COMT gene was associated with 0.46 units lower pain perception compared to the wild type (GG). The anxiety trait score in group AA was lower than in groups GA and GG. The difference reached statistical significance only when comparing AA versus GA (p > 0.042). Analgesic efficacy of nitrous oxide was noticed in 22% of labouring women who reported moderate pain (VAS score 4-7). CONCLUSIONS The COMT gene polymorphism was associated with pain perception and anxiety among parturients. The COMT gene polymorphism GA was associated with negative pain perception among labouring women. Nitrous oxide showed statistical significance in anxiolytic efficacy during labour in women with mild anxiety as a personality trait. Anxiolytic efficacy of nitrous oxide has shown better efficacy in parturients with the COMT gene polymorphism AA.
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Affiliation(s)
- Jadranka Šanjug
- Department of Gynaecology and Obstetrics, General Hospital Zabok and War Veterans’ Hospital, Bračak 8, 49210 Zabok, Croatia
| | - Krunoslav Kuna
- Department of Gynaecology and Obstetrics, Sestre Milosrdnice University Hospital Centre, 10000 Zagreb, Croatia;
| | - Marina Šprem Goldštajn
- Department of Obstetrics and Gynecology, Clinical Hospital Center Zagreb, 10000 Zagreb, Croatia
| | - Lidija Fumić Dunkić
- Division of Anesthesiology, Intensive Care and Pain Medicine, Sestre Milosrdnice University Hospital Center, 10000 Zagreb, Croatia;
| | - Andreja Carek
- Department of Fixed Prosthodontics, School of Dental Medicine, University of Zagreb, Gunduliceva 5, 10000 Zagreb, Croatia
| | - Dubravka Negovetić Vranić
- Department of Pediatric Dentistry, School of Dental Medicine, University of Zagreb, Gunduliceva 5, 10000 Zagreb, Croatia
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Wu YR, Tang JQ, Zhang WN, Zhuang CL, Shi Y. Rational drug design of CB2 receptor ligands: from 2012 to 2021. RSC Adv 2022; 12:35242-35259. [PMID: 36540233 PMCID: PMC9730932 DOI: 10.1039/d2ra05661e] [Citation(s) in RCA: 5] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/08/2022] [Accepted: 12/03/2022] [Indexed: 08/29/2023] Open
Abstract
Cannabinoid receptors belong to the large family of G-protein-coupled receptors, which can be divided into two receptor types, cannabinoid receptor type-1 (CB1) and cannabinoid receptor type-2 (CB2). Marinol, Cesamet and Sativex are marketed CB1 drugs which are still in use and work well, but the central nervous system side effects caused by activation CB1, which limited the development of CB1 ligands. So far, no selective CB2 ligand has been approved for marketing, but lots of its ligands in the clinical stage and pre-clinical stage have positive effects on the treatment of some disease models and have great potential for development. Most selective CB2 agonists are designed and synthesized based on non-selective CB2 agonists through the classical med-chem strategies, e.g. molecular hybridization, scaffold hopping, bioisosterism, etc. During these processes, the balance between selectivity, activity, and pharmacokinetic properties needs to be achieved. Hence, we summarized some reported ligands on the basis of the optimization strategies in recent 10 years, and the limitations and future directions.
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Affiliation(s)
- Yan-Ran Wu
- School of Pharmacy, Key Laboratory of Hui Ethnic Medicine Modernization, Ministry of Education, Ningxia Medical University 1160 Shengli Street Yinchuan 750004 China
| | - Jia-Qin Tang
- School of Pharmacy, Key Laboratory of Hui Ethnic Medicine Modernization, Ministry of Education, Ningxia Medical University 1160 Shengli Street Yinchuan 750004 China
| | - Wan-Nian Zhang
- School of Pharmacy, Key Laboratory of Hui Ethnic Medicine Modernization, Ministry of Education, Ningxia Medical University 1160 Shengli Street Yinchuan 750004 China
- School of Pharmacy, Second Military Medical University 325 Guohe Road Shanghai 200433 China
| | - Chun-Lin Zhuang
- School of Pharmacy, Key Laboratory of Hui Ethnic Medicine Modernization, Ministry of Education, Ningxia Medical University 1160 Shengli Street Yinchuan 750004 China
- School of Pharmacy, Second Military Medical University 325 Guohe Road Shanghai 200433 China
| | - Ying Shi
- School of Pharmacy, Key Laboratory of Hui Ethnic Medicine Modernization, Ministry of Education, Ningxia Medical University 1160 Shengli Street Yinchuan 750004 China
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Alcohol-Related Liver Disease: An Overview on Pathophysiology, Diagnosis and Therapeutic Perspectives. Biomedicines 2022; 10:biomedicines10102530. [PMID: 36289791 PMCID: PMC9599689 DOI: 10.3390/biomedicines10102530] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/15/2022] [Revised: 10/01/2022] [Accepted: 10/08/2022] [Indexed: 11/19/2022] Open
Abstract
Alcohol-related liver disease (ALD) refers to a spectrum of liver manifestations ranging from fatty liver diseases, steatohepatitis, and fibrosis/cirrhosis with chronic inflammation primarily due to excessive alcohol use. Currently, ALD is considered as one of the most prevalent causes of liver disease-associated mortality worldwide. Although the pathogenesis of ALD has been intensively investigated, the present understanding of its biomarkers in the context of early clinical diagnosis is not complete, and novel therapeutic targets that can significantly alleviate advanced forms of ALD are limited. While alcohol abstinence remains the primary therapeutic intervention for managing ALD, there are currently no approved medications for treating ALD. Furthermore, given the similarities and the differences between ALD and non-alcoholic fatty liver disease in terms of disease progression and underlying molecular mechanisms, numerous studies have demonstrated that many therapeutic interventions targeting several signaling pathways, including oxidative stress, inflammatory response, hormonal regulation, and hepatocyte death play a significant role in ALD treatment. Therefore, in this review, we summarized several key molecular targets and their modes of action in ALD progression. We also described the updated therapeutic options for ALD management with a particular emphasis on potentially novel signaling pathways.
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Uba AI, Aluwala H, Liu H, Wu C. Elucidation of partial activation of cannabinoid receptor type 2 and identification of potential partial agonists: Molecular dynamics simulation and structure-based virtual screening. Comput Biol Chem 2022; 99:107723. [PMID: 35850049 DOI: 10.1016/j.compbiolchem.2022.107723] [Citation(s) in RCA: 17] [Impact Index Per Article: 8.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/25/2022] [Revised: 06/27/2022] [Accepted: 07/01/2022] [Indexed: 01/14/2023]
Abstract
Cannabinoid receptor type 2 (CB2R) is a member of the class A G protein-coupled receptor (GPCRs) family and a component of the endocannabinoid system that is modulated by the psychoactive chemical from Cannabis sativa, partial agonist Δ9-tetrahydrocannabinol (Δ9-THC). Selective activation of CB2R allows for the treatment of inflammatory and immune-related conditions without the psychotropic effects of CB1R. While CB2R-selective agonists are available, CB2R partial agonists are scarce. Hence, the pharmacological difference between CB2R full agonists and partial agonists remains to be deciphered, prompting the search for novel partial agonists. Here, using an induced-fit docking approach, we built a partial agonist Δ9-THC bound CB2R system from the inactive CB2R structure (PDB ID: 5ZTY) and performed microsecond molecular dynamics (MD) simulations. The simulations reveal an upward shift of the "toggle switch" W6.48(258) and minor outward movement of the transmembrane helix 6 (TM6). Dynamic network model identifies a possible communication path between the ligand and the toggle switch" W6.48(258). Furthermore, to identify potential CB2R partial agonists, we conducted structure-based virtual screening of ZINC15 "Druglike" library containing 17,900742 compounds against 3 conformations derived from MD simulation of CB2R complexed with partial agonist Δ9-THC using Glide virtual screening protocol comprising various filters with increasing accuracy. Nine diverse compounds predicted to have high MM-GBSA binding energy scores and good ADMET properties (including high gastrointestinal absorption and low toxicity) are proposed as potential CB2R partial agonists.
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Affiliation(s)
- Abdullahi Ibrahim Uba
- Complex Systems Division, Beijing Computational Science Research Center, Beijing 100193, China
| | - Harika Aluwala
- College of Science and Mathematics, Rowan University, Glassboro, NJ 08028, USA
| | - Haiguang Liu
- Complex Systems Division, Beijing Computational Science Research Center, Beijing 100193, China.
| | - Chun Wu
- College of Science and Mathematics, Rowan University, Glassboro, NJ 08028, USA.
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Interactive Effects of HIV Infection and Cannabis Use on Insula Subregion Functional Connectivity. J Neuroimmune Pharmacol 2022; 17:289-304. [PMID: 34427866 DOI: 10.1007/s11481-021-10005-8] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/14/2021] [Accepted: 07/31/2021] [Indexed: 12/29/2022]
Abstract
Chronic inflammation in the central nervous system is one mechanism through which human immunodeficiency virus (HIV) may lead to progressive cognitive decline. Given cannabis's (CB's) anti-inflammatory properties, use prevalence among people living with HIV (PLWH), and evidence implicating the insula in both, we examined independent and interactive effects of HIV and CB on insular circuitry, cognition, and immune function. We assessed resting-state functional connectivity (rsFC) of three insula subregions among 106 participants across four groups (co-occurring: HIV+/CB+; HIV-only: HIV+/CB-; CB-only: HIV-/CB+; controls: HIV-/CB-). Participants completed a neurocognitive battery assessing functioning across multiple domains and self-reported somatic complaints. Blood samples quantified immune function (T-cell counts) and inflammation (tumor necrosis factor alpha [TNF-α]). We observed interactive HIV × CB effects on rsFC strength between two anterior insula (aI) subregions and sensorimotor cortices such that, CB appeared to normalize altered rsFC among non-using PLWH. Specifically, compared to controls, HIV-only and CB-only groups displayed decreased dorsal anterior insula (DI) - postcentral gyrus rsFC and increased ventral anterior insula (VI) - supplementary motor area rsFC, whereas the co-occurring group displayed DI and VI rsFC more akin to that of controls. Altered DI - postcentral rsFC correlated with decreased processing speed and somatic complaints, but did not significantly correlate with inflammation (TNF-α). These outcomes implicate insula - sensorimotor neurocircuitries in HIV and CB and are consistent with prior work suggesting that CB use may normalize insula functioning among PLWH.
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Tang LJ, Han J, Feng YJ, Pu CX, Zhang Y. Comparative study of the efficacy of dexmedetomidine and fentanyl on anxiety and pain of parturients with different COMTva1158met genotypes. BMC Anesthesiol 2022; 22:84. [PMID: 35346044 PMCID: PMC8962552 DOI: 10.1186/s12871-022-01628-2] [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] [Received: 10/22/2021] [Accepted: 03/22/2022] [Indexed: 11/19/2022] Open
Abstract
Objective This study investigates the effects of COMTval158met gene polymorphism on maternal anxiety and pain during delivery and on the analgesic and anxiety efficacy of dexmedetomidine during delivery. Methods Sixty-one pregnant women, who were hospitalized in our hospital from January to November of 2016 were recruited and randomly divided into two groups, F and D groups. The pregnant women in the F group were given labor analgesia with ropivacaine combined with fentanyl. The pregnant women in the D group were given labor analgesia with ropivacaine combined with dexmedetomidine. Before and after labor analgesia, the genotype of COMT in the blood from two groups was detected, and the situation of labor anxiety and analgesia was analyzed. Then, the relationship between labor anxiety, analgesia, and COMT polymorphism was analyzed. Results In the 61 pregnant women, there were 30 women of wild homozygotes (GG) of COMT, 22 women of mutant heterozygotes (GA), and nine women of mutant homozygotes (AA), the mutation rate of allele A was 23.77%. The anxiety status score, anxiety trait score, and pain score in the AA genotype were significantly higher than those in the GG and GA genotype (p < 0.05). There was a significant difference in the efficacy of GG and AA genotypes between groups D and F for treating labor anxiety (p < 0.05), the efficacy of group D was better than that of group F in treating delivery anxiety, there was no significant difference in anxiety scores between the two groups in GA genotypes (p > 0.05); there was no significant difference in pain between group D and F in GG, GA, and AA genotypes (p > 0.05). There was no significant difference in pain and anxiety scores between the three genotypes in group D (p > 0.05), there was significant difference in pain scores among the three genotypes in group F (p < 0.05), but there was no significant difference in anxiety (p > 0.05). Conclusions The mutation of the COMTval158met gene leads to increased anxiety and pain during childbirth. The effect of dexmedetomidine on the anxiety of GG and AA genotypes is better than that of fentanyl, and the mutation of the COMTval158met gene has no impact on dexmedetomidine effect.
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Affiliation(s)
- Li-Jia Tang
- Department of Anesthesiology, Hospital (T.C.M) Affiliated to Southwest Medical University, Chunhui Road 182#, Luzhou, Sichuan, 646000, China
| | - Jiang Han
- Department of Anesthesiology, Hospital (T.C.M) Affiliated to Southwest Medical University, Chunhui Road 182#, Luzhou, Sichuan, 646000, China
| | - Yi-Juan Feng
- Department of Anesthesiology, Hospital (T.C.M) Affiliated to Southwest Medical University, Chunhui Road 182#, Luzhou, Sichuan, 646000, China
| | - Cui-Xia Pu
- Department of Anesthesiology, Hospital (T.C.M) Affiliated to Southwest Medical University, Chunhui Road 182#, Luzhou, Sichuan, 646000, China
| | - Ying Zhang
- Department of Anesthesiology, Hospital (T.C.M) Affiliated to Southwest Medical University, Chunhui Road 182#, Luzhou, Sichuan, 646000, China.
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Yang K, Choi SE, Jeong WI. Hepatic Cannabinoid Signaling in the Regulation of Alcohol-Associated Liver Disease. Alcohol Res 2021; 41:12. [PMID: 34646717 PMCID: PMC8496755 DOI: 10.35946/arcr.v41.1.12] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022] Open
Abstract
PURPOSE The endocannabinoid system has emerged as a key regulatory signaling pathway in the pathophysiology of alcohol-associated liver disease (ALD). More than 30 years of research have established different roles of endocannabinoids and their receptors in various aspects of liver diseases, such as steatosis, inflammation, and fibrosis. However, pharmacological applications of the endocannabinoid system for the treatment of ALD have not been successful because of psychoactive side effects, despite some beneficial effects. Thus, a more delicate and detailed elucidation of the mechanism linking the endocannabinoid system and ALD may be of paramount significance in efforts to apply the system to the treatment of ALD. SEARCH METHODS Three electronic databases (PubMed, MEDLINE, and Cochrane Library) were used for literature search from November 1988 to April 2021. Major keywords used for literature searches were “cannabinoid,” “cannabinoid receptor,” “ALD,” “steatosis,” and “fibrosis.” SEARCH RESULTS According to the inclusion and exclusion criteria, the authors selected 47 eligible full-text articles out of 2,691 searched initially. Studies in the past 3 decades revealed the opposite effects of cannabinoid receptors CB1R and CB2R on steatosis, inflammation, and fibrosis in ALD. DISCUSSION AND CONCLUSIONS This review summarizes the endocannabinoid signaling in the general physiology of the liver, the pathogenesis of ALD, and some of the potential therapeutic implications of cannabinoid-based treatments for ALD.
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Affiliation(s)
- Keungmo Yang
- Laboratory of Liver Research, Graduate School of Medical Science and Engineering, Korea Advanced Institute of Science and Technology, Daejeon 34141, Republic of Korea
| | - Sung Eun Choi
- Laboratory of Liver Research, Graduate School of Medical Science and Engineering, Korea Advanced Institute of Science and Technology, Daejeon 34141, Republic of Korea
| | - Won-Il Jeong
- Laboratory of Liver Research, Graduate School of Medical Science and Engineering, Korea Advanced Institute of Science and Technology, Daejeon 34141, Republic of Korea.,Biomedical Research Center, Korea Advanced Institute of Science and Technology, Daejeon 34141, Republic of Korea
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Allosteric Modulation of Cannabinoid Receptor 1-Current Challenges and Future Opportunities. Int J Mol Sci 2019; 20:ijms20235874. [PMID: 31771126 PMCID: PMC6928801 DOI: 10.3390/ijms20235874] [Citation(s) in RCA: 20] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/01/2019] [Revised: 11/19/2019] [Accepted: 11/20/2019] [Indexed: 02/07/2023] Open
Abstract
The cannabinoid receptor type 1 (CB1R), a G protein-coupled receptor (GPCR), plays an essential role in the control of many physiological processes such as hunger, memory loss, gastrointestinal activity, catalepsy, fear, depression, and chronic pain. Therefore, it is an attractive target for drug discovery to manage pain, neurodegenerative disorders, obesity, and substance abuse. However, the psychoactive adverse effects, generated by CB1R activation in the brain, limit the use of the orthosteric CB1R ligands as drugs. The discovery of CB1R allosteric modulators during the last decade provided new tools to target the CB1R. Moreover, application of the site-directed mutagenesis in combination with advanced physical methods, especially X-ray crystallography and computational modeling, has opened new horizons for understanding the complexity of the structure, function, and activity of cannabinoid receptors. In this paper, we present the latest advances in research on the CB1R, its allosteric modulation and allosteric ligands, and their translational potential. We focused on structural essentials of the cannabinoid 1 receptor- ligand (drug) interactions, as well as modes of CB1R signaling regulation.
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Balkhi MY, Willette-Brown J, Wittmann G, Hu Y. IKKα deficiency disrupts the development of marginal zone and follicular B cells. Genes Immun 2018; 20:224-233. [PMID: 29740197 DOI: 10.1038/s41435-018-0025-0] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/17/2017] [Accepted: 01/15/2018] [Indexed: 01/10/2023]
Abstract
Only few genes have been confidently identified to be involved in the Follicular (FO) and Marginal Zone (MZ) B cell differentiation, migration, and retention in the periphery. Our group previously observed that IKKα kinase inactive mutant mice IKKαK44A/K44A have significantly lower number of MZ B cells whereas FO B cell numbers appeared relatively normal. Because kinase dead IKKα can retain some of its biological functions that may interfere in revealing its actual role in the MZ and FO B cell differentiation. Therefore, in the current study, we genetically deleted IKKα from the pro-B cell lineage that revealed novel functions of IKKα in the MZ and FO B lymphocyte development. The loss of IKKα produces a significant decline in the percentage of immature B lymphocytes, mature marginal zone B cells, and follicular B cells along with a severe disruption of splenic architecture of marginal and follicular zones. IKKα deficiency affect the recirculation of mature B cells through bone marrow. A transplant of IKKα knockout fetal liver cells into Rag-/- mice shows a significant reduction compared to control in the B cells recirculating through bone marrow. To reveal the genes important in the B cell migration, a high throughput gene expression analysis was performed on the IKKα deficient recirculating mature B cells (B220+IgMhi). That revealed significant changes in the expression of genes involved in the B lymphocyte survival, homing and migration. And several among those genes identified belong to G protein family. Taken together, this study demonstrates that IKKα forms a vial axis controlling the genes involved in MZ and FO B cell differentiation and migration.
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Affiliation(s)
- Mumtaz Y Balkhi
- Division of Hematology/Oncology, Department of Medicine, Tufts University School of Medicine, Boston, MA, USA.
| | - Jami Willette-Brown
- Cancer and Inflammation Program, Center for Cancer Research, National Cancer Institute, National Institute of Health, Frederick, MD, USA
| | - Gabor Wittmann
- Division of Endocrinology, Diabetes and Metabolism, Department of Medicine, Tufts University School of Medicine, Boston, MA, USA
| | - Yinling Hu
- Cancer and Inflammation Program, Center for Cancer Research, National Cancer Institute, National Institute of Health, Frederick, MD, USA
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Ruehle S, Wager-Miller J, Straiker A, Farnsworth J, Murphy MN, Loch S, Monory K, Mackie K, Lutz B. Discovery and characterization of two novel CB1 receptor splice variants with modified N-termini in mouse. J Neurochem 2017; 142:521-533. [PMID: 28608535 PMCID: PMC5554085 DOI: 10.1111/jnc.14099] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/10/2016] [Revised: 05/15/2017] [Accepted: 06/04/2017] [Indexed: 12/26/2022]
Abstract
Numerous studies have been carried out in the mouse model, investigating the role of the cannabinoid receptor type 1 (CB1). However, mouse CB1 (mCB1) receptor differs from human CB1 (hCB1) receptor in 13 amino acid residues. Two splice variants, hCB1a and hCB1b, diverging in their amino-termini, have been reported to be unique for hCB1 and, via different signaling properties, contribute to CB1 receptor physiology and pathophysiology. We hypothesized that splice variants also exist for the mCB1 receptor and have different signaling properties. On murine hippocampal cDNA, we identified two novel mCB1 receptor splice variants generated by splicing of introns with 117 bp and 186 bp in the N-terminal domain, corresponding to deletions of 39 or 62 amino acids, respectively. The mRNAs for the splice variants mCB1a and mCB1b are expressed at low levels in different brain regions. Western blot analysis of protein extracts from stably transfected HEK293 cells indicates a strongly reduced glycosylation because of the absence of two glycosylation sites in mCB1b. On-cell western analysis in these stable lines revealed increased internalization of mCB1a and mCB1b upon stimulation with the agonist WIN55,212-2 as compared to mCB1. Results also point toward an increased affinity to SR141716 for mCB1a, as well as slightly enhanced inhibition of neurotransmission compared to mCB1. In mCB1b, agonist-induced MAPK phosphorylation was decreased compared to mCB1 and mCB1a. Identification of mouse CB1 receptor splice variants may help to explain differences found between human and mouse endocannabinoid systems and improve the understanding of CB1 receptor signaling and trafficking in different species.
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Affiliation(s)
- Sabine Ruehle
- Institute of Physiological Chemistry, University Medical Center of the Johannes Gutenberg University Mainz, 55099 Mainz, Germany
| | - James Wager-Miller
- Department of Psychological and Brain Sciences, Gill Center for Biomolecular Science, Indiana University, Bloomington, IN 47405, USA
| | - Alex Straiker
- Department of Psychological and Brain Sciences, Gill Center for Biomolecular Science, Indiana University, Bloomington, IN 47405, USA
| | - Jill Farnsworth
- Department of Psychological and Brain Sciences, Gill Center for Biomolecular Science, Indiana University, Bloomington, IN 47405, USA
| | - Michelle N. Murphy
- Department of Psychological and Brain Sciences, Gill Center for Biomolecular Science, Indiana University, Bloomington, IN 47405, USA
| | - Sebastian Loch
- Institute of Physiological Chemistry, University Medical Center of the Johannes Gutenberg University Mainz, 55099 Mainz, Germany
| | - Krisztina Monory
- Institute of Physiological Chemistry, University Medical Center of the Johannes Gutenberg University Mainz, 55099 Mainz, Germany
| | - Ken Mackie
- Department of Psychological and Brain Sciences, Gill Center for Biomolecular Science, Indiana University, Bloomington, IN 47405, USA
| | - Beat Lutz
- Institute of Physiological Chemistry, University Medical Center of the Johannes Gutenberg University Mainz, 55099 Mainz, Germany
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Abstract
OPINION STATEMENT Despite the political and social controversy affiliated with it, the medical community must come to the realization that cannabinoids exist as a ubiquitous signaling system in many organ systems. Our understanding of cannabinoids and how they relate not only to homeostasis but also in disease states must be furthered through research, both clinically and in the laboratory. The identification of the cannabinoid receptors in the early 1990s have provided us with the perfect target of translational research. Already, much has been done with cannabinoids and the nervous system. Here, we explore the implications it has for the gastrointestinal tract. Most therapeutics currently on the market presently target only one aspect of the cannabinoid system. Our main purpose here is to highlight areas of research and potential avenues of discovery that the cannabinoid system has yet to reveal.
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Affiliation(s)
- Zachary Wilmer Reichenbach
- Center for Substance Abuse Research (CSAR), Lewis Katz School of Medicine, Temple University, Philadelphia, PA, USA.,Section of Gastroenterology, Department of Medicine, Lewis Katz School of Medicine, Temple University, Philadelphia, PA, USA
| | - Ron Schey
- Section of Gastroenterology, Department of Medicine, Lewis Katz School of Medicine, Temple University, Philadelphia, PA, USA.
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Khedr AIM, Ibrahim SRM, Mohamed GA, Ahmed HEA, Ahmad AS, Ramadan MA, El-Baky AEA, Yamada K, Ross SA. New ursane triterpenoids from Ficus pandurata and their binding affinity for human cannabinoid and opioid receptors. Arch Pharm Res 2016; 39:897-911. [PMID: 27350550 PMCID: PMC5590819 DOI: 10.1007/s12272-016-0784-y] [Citation(s) in RCA: 21] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/12/2016] [Accepted: 06/20/2016] [Indexed: 01/11/2023]
Abstract
Phytochemical investigation of Ficus pandurata Hance (Moraceae) fruits has led to the isolation of two new triterpenoids, ficupanduratin A [1β-hydroxy-3β-acetoxy-11α-methoxy-urs-12-ene] (11) and ficupanduratin B [21α-hydroxy-3β-acetoxy-11α-methoxy-urs-12-ene] (17), along with 20 known compounds: α-amyrin acetate (1), α-amyrin (2), 3β-acetoxy-20-taraxasten-22-one (3), 3β-acetoxy-11α-methoxy-olean-12-ene (4), 3β-acetoxy-11α-methoxy-12-ursene (5), 11-oxo-α-amyrin acetate (6), 11-oxo-β-amyrin acetate (7), palmitic acid (8), stigmast-4,22-diene-3,6-dione (9), stigmast-4-ene-3,6-dione (10), stigmasterol (12), β-sitosterol (13), stigmast-22-ene-3,6-dione (14), stigmastane-3,6-dione (15), 3β,21β-dihydroxy-11α-methoxy-olean-12-ene (16), 3β-hydroxy-11α-methoxyurs-12-ene (18), 6-hydroxystigmast-4,22-diene-3-one (19), 6-hydroxystigmast-4-ene-3-one (20), 11α,21α-dihydroxy-3β-acetoxy-urs-12-ene (21), and β-sitosterol-3-O-β-D-glucopyranoside (22). Compound 21 is reported for the first time from a natural source. The structures of the 20 compounds were elucidated on the basis of IR, 1D ((1)H and (13)C), 2D ((1)H-(1)H COSY, HSQC, HMBC and NOESY) NMR and MS spectroscopic data, in addition to comparison with literature data. The isolated compounds were evaluated for their anti-microbial, anti-malarial, anti-leishmanial, and cytotoxic activities. In addition, their radioligand displacement affinity on opioid and cannabinoid receptors was assessed. Compounds 4, 11, and 15 exhibited good affinity towards the CB2 receptor, with displacement values of 69.7, 62.5 and 86.5 %, respectively. Furthermore, the binding mode of the active compounds in the active site of the CB2 cannabinoid receptors was investigated through molecular modelling.
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Affiliation(s)
- Amgad I M Khedr
- Department of Pharmacognosy, Faculty of Pharmacy, Port Said University, Port Said, 42526, Egypt
| | - Sabrin R M Ibrahim
- Department of Pharmacognosy and Pharmaceutical Chemistry, College of Pharmacy, Taibah University, Al Madinah Al Munawarah, 30078, Saudi Arabia.
- Department of Pharmacognosy, Faculty of Pharmacy, Assuit University, Assuit, 71526, Egypt.
| | - Gamal A Mohamed
- Department of Natural Products and Alternative Medicine, Faculty of Pharmacy, King Abdulaziz University, Jeddah, 21589, Saudi Arabia
- Department of Pharmacognosy, Faculty of Pharmacy, Al-Azhar University, Assuit Branch, Assuit, 71524, Egypt
| | - Hany E A Ahmed
- Department of Pharmacognosy and Pharmaceutical Chemistry, College of Pharmacy, Taibah University, Al Madinah Al Munawarah, 30078, Saudi Arabia
- Pharmaceutical Organic Chemistry Department, Faculty of Pharmacy, Al-Azhar University, Cairo, Egypt
| | - Amany S Ahmad
- Department of Pharmacognosy, Faculty of Pharmacy, Assuit University, Assuit, 71526, Egypt
| | - Mahmoud A Ramadan
- Department of Pharmacognosy, Faculty of Pharmacy, Assuit University, Assuit, 71526, Egypt
| | - Atef E Abd El-Baky
- Department of Biochemistry, Faculty of Pharmacy, Port Said University, Port Said, 42526, Egypt
| | - Koji Yamada
- Garden for Medicinal Plants, Graduate School of Biomedical Sciences, Nagasaki University, Bunkyo-machi 1-14, Nagasaki, 852-8521, Japan
| | - Samir A Ross
- National Center for Natural Products Research, and Department of Pharmacognosy, School of Pharmacy, University of Mississippi, University, MS, 38677, USA
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Jourdan T, Godlewski G, Kunos G. Endocannabinoid regulation of β-cell functions: implications for glycaemic control and diabetes. Diabetes Obes Metab 2016; 18:549-57. [PMID: 26880114 PMCID: PMC5045244 DOI: 10.1111/dom.12646] [Citation(s) in RCA: 42] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 11/24/2015] [Revised: 02/08/2016] [Accepted: 02/11/2016] [Indexed: 01/11/2023]
Abstract
Visceral obesity is a major risk factor for the development of insulin resistance which can progress to overt type 2 diabetes (T2D) with loss of β-cell function and, ultimately, loss of β-cells. Insulin secretion by β-cells of the pancreatic islets is tightly coupled to blood glucose concentration and modulated by a large number of blood-borne or locally released mediators, including endocannabinoids. Obesity and its complications, including T2D, are associated with increased activity of the endocannabinoid/CB1 receptor (CB1 R) system, as indicated by the therapeutic effects of CB1 R antagonists. Similar beneficial effects of CB1 R antagonists with limited brain penetrance indicate the important role of CB1 R in peripheral tissues, including the endocrine pancreas. Pancreatic β-cells express all of the components of the endocannabinoid system, and endocannabinoids modulate their function via both autocrine and paracrine mechanisms, which influence basal and glucose-induced insulin secretion and also affect β-cell proliferation and survival. The present brief review will survey available information on the modulation of these processes by endocannabinoids and their receptors, with an attempt to assess the contribution of such effects to glycaemic control in T2D and insulin resistance.
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Affiliation(s)
- T Jourdan
- Laboratory of Physiologic Studies, National Institute on Alcohol Abuse and Alcoholism, National Institutes of Health, Bethesda, MD, USA
| | - G Godlewski
- Laboratory of Physiologic Studies, National Institute on Alcohol Abuse and Alcoholism, National Institutes of Health, Bethesda, MD, USA
| | - G Kunos
- Laboratory of Physiologic Studies, National Institute on Alcohol Abuse and Alcoholism, National Institutes of Health, Bethesda, MD, USA
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Dunn SL, Wilkinson JM, Crawford A, Bunning RAD, Le Maitre CL. Expression of Cannabinoid Receptors in Human Osteoarthritic Cartilage: Implications for Future Therapies. Cannabis Cannabinoid Res 2016; 1:3-15. [PMID: 28861474 PMCID: PMC5576594 DOI: 10.1089/can.2015.0001] [Citation(s) in RCA: 39] [Impact Index Per Article: 4.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/16/2022] Open
Abstract
Introduction: Cannabinoids have shown to reduce joint damage in animal models of arthritis and reduce matrix metalloproteinase expression in primary human osteoarthritic (OA) chondrocytes. The actions of cannabinoids are mediated by a number of receptors, including cannabinoid receptors 1 and 2 (CB1 and CB2), G-protein-coupled receptors 55 and 18 (GPR55 and GPR18), transient receptor potential vanilloid-1 (TRPV1), and peroxisome proliferator-activated receptors alpha and gamma (PPARα and PPARγ). However, to date very few studies have investigated the expression and localization of these receptors in human chondrocytes, and expression during degeneration, and thus their potential in clinical applications is unknown. Methods: Human articular cartilage from patients with symptomatic OA was graded histologically and the expression and localization of cannabinoid receptors within OA cartilage and underlying bone were determined immunohistochemically. Expression levels across regions of cartilage and changes with degeneration were investigated. Results: Expression of all the cannabinoid receptors investigated was observed with no change with grade of degeneration seen in the expression of CB1, CB2, GPR55, PPARα, and PPARγ. Conversely, the number of chondrocytes within the deep zone of cartilage displaying immunopositivity for GPR18 and TRPV1 was significantly decreased in degenerate cartilage. Receptor expression was higher in chondrocytes than in osteocytes in the underlying bone. Conclusions: Chondrocytes from OA joints were shown to express a wide range of cannabinoid receptors even in degenerate tissues, demonstrating that these cells could respond to cannabinoids. Cannabinoids designed to bind to receptors inhibiting the catabolic and pain pathways within the arthritic joint, while avoiding psychoactive effects, could provide potential arthritis therapies.
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Affiliation(s)
- Sara L Dunn
- Faculty of Health and Wellbeing, Biomolecular Sciences Research Centre, Sheffield Hallam University, Sheffield, United Kingdom
| | - Jeremy Mark Wilkinson
- Academic Unit of Bone Metabolism, Department of Human Metabolism, University of Sheffield, Sheffield, United Kingdom
| | - Aileen Crawford
- Centre for Biomaterials and Tissue Engineering, School of Clinical Dentistry, University of Sheffield, Sheffield, United Kingdom
| | - Rowena A D Bunning
- Faculty of Health and Wellbeing, Biomolecular Sciences Research Centre, Sheffield Hallam University, Sheffield, United Kingdom
| | - Christine L Le Maitre
- Faculty of Health and Wellbeing, Biomolecular Sciences Research Centre, Sheffield Hallam University, Sheffield, United Kingdom
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Bedlack RS, Joyce N, Carter GT, Paganoni S, Karam C. Complementary and Alternative Therapies in Amyotrophic Lateral Sclerosis. Neurol Clin 2015; 33:909-36. [PMID: 26515629 PMCID: PMC4712627 DOI: 10.1016/j.ncl.2015.07.008] [Citation(s) in RCA: 25] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/06/2023]
Abstract
Given the severity of their illness and lack of effective disease-modifying agents, it is not surprising that most patients with amyotrophic lateral sclerosis (ALS) consider trying complementary and alternative therapies. Some of the most commonly considered alternative therapies include special diets, nutritional supplements, cannabis, acupuncture, chelation, and energy healing. This article reviews these in detail. The authors also describe 3 models by which physicians may frame discussions about alternative therapies: paternalism, autonomy, and shared decision making. Finally, the authors review a program called ALSUntangled, which uses shared decision making to review alternative therapies for ALS.
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Affiliation(s)
- Richard S Bedlack
- Department of Neurology, Duke University Medical Center, Durham, NC 27702, USA.
| | - Nanette Joyce
- Department of Physical Medicine and Rehabilitation, University of California, Davis School of Medicine, 4860 Y Street Suite 3850, Sacramento, CA 95817, USA
| | - Gregory T Carter
- Department of Physical Medicine and Rehabilitation, St. Luke's Rehabilitation Institute, 711 South Cowley, Spokane, WA 99202, USA
| | - Sabrina Paganoni
- Spaulding Rehabilitation Hospital, Boston VA Health Care System, Harvard Medical School, Massachussets General Hospital, Boston, MA 02114, USA
| | - Chafic Karam
- Department of Neurology, University of North Carolina School of Medicine, 170 Manning Drive, Campus Box 7025, Chapel Hill, NC 27599-7025, USA
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Dazzi L, Talani G, Biggio F, Utzeri C, Lallai V, Licheri V, Lutzu S, Mostallino MC, Secci PP, Biggio G, Sanna E. Involvement of the cannabinoid CB1 receptor in modulation of dopamine output in the prefrontal cortex associated with food restriction in rats. PLoS One 2014; 9:e92224. [PMID: 24632810 PMCID: PMC3954872 DOI: 10.1371/journal.pone.0092224] [Citation(s) in RCA: 21] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/17/2013] [Accepted: 02/20/2014] [Indexed: 11/30/2022] Open
Abstract
Increase in dopamine output on corticolimbic structures, such as medial prefrontal cortex (mPFC) and nucleus accumbens, has been related to reward effects associated with palatable food or food presentation after a fasting period. The endocannabinoid system regulates feeding behavior through a modulatory action on different neurotransmitter systems, including the dopaminergic system. To elucidate the involvement of type 1 cannabinoid receptors in the regulation of dopamine output in the mPFC associated with feeding in hungry rats, we restricted the food availability to a 2-h period daily for 3 weeks. In food-restricted rats the extracellular dopamine concentration in the mPFC increased starting 80 min before food presentation and returned to baseline after food removal. These changes were attenuated in animals treated with the CB1 receptor antagonist SR141716. To better understand how food restriction can change the response of mesocortical dopaminergic neurons, we studied several components of the neuronal circuit that regulates dopamine output in the mPFC. Patch-clamp experiments revealed that the inhibitory effect of the CB1 receptor agonist WIN 55,212-2 on GABAergic sIPSC frequency was diminished in mPFC neurons of FR compared to fed ad libitum rats. The basal sIPSC frequency resulted reduced in mPFC neurons of food-restricted rats, suggestive of an altered regulation of presynaptic GABA release; these changes were accompanied by an enhanced excitability of mPFC and ventral tegmental area neurons. Finally, type 1 cannabinoid receptor expression in the mPFC was reduced in food-restricted rats. Together, our data support an involvement of the endocannabinoid system in regulation of dopamine release in the mPFC through changes in GABA inhibitory synapses and suggest that the emphasized feeding-associated increase in dopamine output in the mPFC of food-restricted rats might be correlated with an altered expression and function of type 1 cannabinoid receptor in this brain region.
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Affiliation(s)
- Laura Dazzi
- Department of Life and Environmental Sciences, Section of Neuroscience and Anthropology, Centre of Excellence for the Neurobiology of Dependence, University of Cagliari, Monserrato, Cagliari, Italy
- * E-mail:
| | - Giuseppe Talani
- Institute of Neuroscience, National Research Council, Monserrato, Cagliari, Italy
| | - Francesca Biggio
- Department of Life and Environmental Sciences, Section of Neuroscience and Anthropology, Centre of Excellence for the Neurobiology of Dependence, University of Cagliari, Monserrato, Cagliari, Italy
| | - Cinzia Utzeri
- Department of Life and Environmental Sciences, Section of Neuroscience and Anthropology, Centre of Excellence for the Neurobiology of Dependence, University of Cagliari, Monserrato, Cagliari, Italy
| | - Valeria Lallai
- Department of Life and Environmental Sciences, Section of Neuroscience and Anthropology, Centre of Excellence for the Neurobiology of Dependence, University of Cagliari, Monserrato, Cagliari, Italy
| | - Valentina Licheri
- Department of Life and Environmental Sciences, Section of Neuroscience and Anthropology, Centre of Excellence for the Neurobiology of Dependence, University of Cagliari, Monserrato, Cagliari, Italy
| | - Stefano Lutzu
- Department of Life and Environmental Sciences, Section of Neuroscience and Anthropology, Centre of Excellence for the Neurobiology of Dependence, University of Cagliari, Monserrato, Cagliari, Italy
| | | | - Pietro Paolo Secci
- Department of Life and Environmental Sciences, Section of Neuroscience and Anthropology, Centre of Excellence for the Neurobiology of Dependence, University of Cagliari, Monserrato, Cagliari, Italy
| | - Giovanni Biggio
- Department of Life and Environmental Sciences, Section of Neuroscience and Anthropology, Centre of Excellence for the Neurobiology of Dependence, University of Cagliari, Monserrato, Cagliari, Italy
- Institute of Neuroscience, National Research Council, Monserrato, Cagliari, Italy
| | - Enrico Sanna
- Department of Life and Environmental Sciences, Section of Neuroscience and Anthropology, Centre of Excellence for the Neurobiology of Dependence, University of Cagliari, Monserrato, Cagliari, Italy
- Institute of Neuroscience, National Research Council, Monserrato, Cagliari, Italy
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Baillie GL, Horswill JG, Anavi-Goffer S, Reggio PH, Bolognini D, Abood ME, McAllister S, Strange PG, Stephens GJ, Pertwee RG, Ross RA. CB(1) receptor allosteric modulators display both agonist and signaling pathway specificity. Mol Pharmacol 2012; 83:322-38. [PMID: 23160940 DOI: 10.1124/mol.112.080879] [Citation(s) in RCA: 98] [Impact Index Per Article: 8.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022] Open
Abstract
We have previously identified allosteric modulators of the cannabinoid CB(1) receptor (Org 27569, PSNCBAM-1) that display a contradictory pharmacological profile: increasing the specific binding of the CB(1) receptor agonist [(3)H]CP55940 but producing a decrease in CB(1) receptor agonist efficacy. Here we investigated the effect one or both compounds in a broad range of signaling endpoints linked to CB(1) receptor activation. We assessed the effect of these compounds on CB(1) receptor agonist-induced [(35)S]GTPγS binding, inhibition, and stimulation of forskolin-stimulated cAMP production, phosphorylation of extracellular signal-regulated kinases (ERK), and β-arrestin recruitment. We also investigated the effect of these allosteric modulators on CB(1) agonist binding kinetics. Both compounds display ligand dependence, being significantly more potent as modulators of CP55940 signaling as compared with WIN55212 and having little effect on [(3)H]WIN55212 binding. Org 27569 displays biased antagonism whereby it inhibits: agonist-induced guanosine 5'-O-(3-[(35)S]thio)triphosphate ([(35)S]GTPγS) binding, simulation (Gα(s)-mediated), and inhibition (Gα(i)-mediated) of cAMP production and β-arrestin recruitment. In contrast, it acts as an enhancer of agonist-induced ERK phosphorylation. Alone, the compound can act also as an allosteric agonist, increasing cAMP production and ERK phosphorylation. We find that in both saturation and kinetic-binding experiments, the Org 27569 and PSNCBAM-1 appeared to influence only orthosteric ligand maximum occupancy rather than affinity. The data indicate that the allosteric modulators share a common mechanism whereby they increase available high-affinity CB(1) agonist binding sites. The receptor conformation stabilized by the allosterics appears to induce signaling and also selectively traffics orthosteric agonist signaling via the ERK phosphorylation pathway.
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Affiliation(s)
- Gemma L Baillie
- School of Medical Sciences, Institute of Medical Sciences, University of Aberdeen, Aberdeen, United Kingdom
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Rühl T, Deuther-Conrad W, Fischer S, Günther R, Hennig L, Krautscheid H, Brust P. Cannabinoid receptor type 2 (CB2)-selective N-aryl-oxadiazolyl-propionamides: synthesis, radiolabelling, molecular modelling and biological evaluation. Org Med Chem Lett 2012; 2:32. [PMID: 23067874 PMCID: PMC3598492 DOI: 10.1186/2191-2858-2-32] [Citation(s) in RCA: 28] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/11/2012] [Accepted: 09/21/2012] [Indexed: 12/02/2022] Open
Abstract
Background The endocannabinoid system is involved in many physiological and pathological processes. Two receptors (cannabinoid receptor type 1 (CB1) and type 2 (CB2)) are known so far. Many unwanted psychotic side effects of inhibitors of this system can be addressed to the interaction with CB1. While CB1 is one of the most abundant neuroreceptors, CB2 is expressed in the brain only at very low levels. Thus, highly potent and selective compounds for CB2 are desired. N-aryl-((hetero)aromatic)-oxadiazolyl-propionamides represent a promising class of such selective ligands for the human CB2. Here, a library of various derivatives is studied for suitable routes for labelling with 18F. Such 18F-labelled compounds can then be employed as CB2-selective radiotracers for molecular imaging studies employing positron emission tomography (PET). Results By varying the N-arylamide substructure, we explored the binding pocket of the human CB2 receptor and identified 9-ethyl-9H-carbazole amide as the group with optimal size. Radioligand replacement experiments revealed that the modification of the (hetero)aromatic moiety in 3-position of the 1,2,4-oxadiazoles shows only moderate impact on affinity to CB2 but high impact on selectivity towards CB2 with respect to CB1. Further, we could show by autoradiography studies that the most promising compounds bind selectively on CB2 receptors in mouse spleen tissue. Molecular docking studies based on a novel three-dimensional structural model of the human CB2 receptor in its activated form indicate that the compounds bind with the N-arylamide substructure in the binding pocket. 18F labelling at the (hetero)aromatic moiety at the opposite site of the compounds via radiochemistry was carried out. Conclusions The synthesized CB2-selective compounds have high affinity towards CB2 and good selectivity against CB1. The introduction of labelling groups at the (hetero)aromatic moiety shows only moderate impact on CB2 affinity, indicating the introduction of potential labelling groups at this position as a promising approach to develop CB2-selective ligands suitable for molecular imaging with PET. The high affinity for human CB2 and selectivity against human CB1 of the herein presented compounds renders them as suitable candidates for molecular imaging studies.
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Affiliation(s)
- Thomas Rühl
- Department of Neuroradiopharmaceuticals, Institute of Radiopharmacy, Research Site Leipzig, Helmholtz-Zentrum Dresden-Rossendorf e,V,, Permoserstr, 15, Leipzig, 04318, Germany.
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20
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Console-Bram L, Marcu J, Abood ME. Cannabinoid receptors: nomenclature and pharmacological principles. Prog Neuropsychopharmacol Biol Psychiatry 2012; 38:4-15. [PMID: 22421596 PMCID: PMC3378782 DOI: 10.1016/j.pnpbp.2012.02.009] [Citation(s) in RCA: 109] [Impact Index Per Article: 9.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 10/10/2011] [Revised: 02/20/2012] [Accepted: 02/20/2012] [Indexed: 02/06/2023]
Abstract
The CB1 and CB2 cannabinoid receptors are members of the G protein-coupled receptor (GPCR) family that are pharmacologically well defined. However, the discovery of additional sites of action for endocannabinoids as well as synthetic cannabinoid compounds suggests the existence of additional cannabinoid receptors. Here we review this evidence, as well as the current nomenclature for classifying a target as a cannabinoid receptor. Basic pharmacological definitions, principles and experimental conditions are discussed in order to place in context the mechanisms underlying cannabinoid receptor activation. Constitutive (agonist-independent) activity is observed with the overexpression of many GPCRs, including cannabinoid receptors. Allosteric modulators can alter the pharmacological responses of cannabinoid receptors. The complex molecular architecture of each of the cannabinoid receptors allows for a single receptor to recognize multiple classes of compounds and produce an array of distinct downstream effects. Natural polymorphisms and alternative splice variants may also contribute to their pharmacological diversity. As our knowledge of the distinct differences grows, we may be able to target select receptor conformations and their corresponding pharmacological responses. Importantly, the basic biology of the endocannabinoid system will continue to be revealed by ongoing investigations.
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Affiliation(s)
- Linda Console-Bram
- Center for Substance Abuse Research, Temple University School of Medicine, Philadelphia, PA, USA 19140
| | - Jahan Marcu
- Center for Substance Abuse Research, Temple University School of Medicine, Philadelphia, PA, USA 19140,Department of Anatomy and Cell Biology, Temple University School of Medicine, Philadelphia, PA, USA 19140
| | - Mary E. Abood
- Center for Substance Abuse Research, Temple University School of Medicine, Philadelphia, PA, USA 19140,Department of Anatomy and Cell Biology, Temple University School of Medicine, Philadelphia, PA, USA 19140
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Engeli S. Central and peripheral cannabinoid receptors as therapeutic targets in the control of food intake and body weight. Handb Exp Pharmacol 2012:357-381. [PMID: 22249824 DOI: 10.1007/978-3-642-24716-3_17] [Citation(s) in RCA: 41] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 05/31/2023]
Abstract
The endocannabinoid system consists of lipid-derived agonists that activate cannabinoid (CB) receptors. CB receptor agonists, namely, the phytocannabinoid Δ(9)-THC and the endocannabinoid anandamide, increase hunger sensation and food intake. These discoveries led to the clinical use of Δ(9)-THC derivatives for the treatment of cancer and HIV-related nausea and cachexia. Animal studies clarified the important role of CB1 receptors in the hypothalamus and in the limbic system in mediating orexigenic effects. In parallel, data on CB1-specific blockade either by drugs or by genetic ablation further demonstrated that CB1 inhibition protects against weight gain induced by high-fat feeding and reduces body weight in obese animals and humans. The mechanisms of weight reduction by CB1 blockade are complex: they comprise interactions with several orexigenic and anorexigenic neuropeptides and hormones, regulation of sympathetic activity, influences on mitochondrial function, and on lipogenesis. Although these mechanisms appear to be mainly mediated by the CNS, weight loss also occurs when drugs that do not reach CNS concentrations sufficient to inhibit CB1 signaling are used. The development of peripherally restricted CB1 inverse agonists and antagonists opened new routes in CB1 pharmacology because centrally acting CB1 inverse agonists, e.g., rimonabant and taranabant, exerted unacceptable side effects that precluded their further development and application as weight loss drugs. Tissue and circulating endocannabinoid concentrations are often increased in animal models of obesity and in obese humans, especially those with visceral fat accumulation. Thus, further research on CB1 inhibition is still promising to treat human obesity.
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Affiliation(s)
- Stefan Engeli
- Hannover Medical School, Institute of Clinical Pharmacology, Carl-Neuberg-Straße 1, 30625 Hannover, Germany.
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Onaivi ES. Commentary: Functional Neuronal CB2 Cannabinoid Receptors in the CNS. Curr Neuropharmacol 2011; 9:205-8. [PMID: 21886591 PMCID: PMC3137183 DOI: 10.2174/157015911795017416] [Citation(s) in RCA: 31] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/01/2009] [Revised: 04/17/2010] [Accepted: 05/26/2010] [Indexed: 11/22/2022] Open
Abstract
Cannabinoids are the constituents of the marijuana plant (Cannabis sativa). There are numerous cannabinoids and other natural compounds that have been reported in the cannabis plant. The recent progress in marijuana-cannabinoid research include the discovery of an endocannabinoid system with specific genes coding for cannabinoid receptors (CBRs) that are activated by smoking marijuana, and that the human body and brain makes its own marijuana-like substances called endocannabinoids that also activate CBRs. This new knowledge and progress about cannabinoids and endocannabinoids indicate that a balanced level of endocannabinoids is important for pregnancy and that the breast milk in animals and humans has endocannabinoids for the growth and development of the new born. There are two well characterized cannabinoid receptors termed CB1-Rs and CB2-Rs and these CBRs are perhaps the most abundant G-protein coupled receptors that are expressed at high levels in many regions of the mammalian brain. The expression of CB1-Rs in the brain and periphery and the identification of CB2-Rs in immune cells and during inflammation has been extensively studied and characterized. However, the expression of functional neuronal CB2-Rs in the CNS has been much less well established and characterized in comparison to the expression of abundant brain CB1-Rs and functional neuronal CB2-Rs has ignited debate and controversy. While the issue of the specificity of CB2-R antibodies remains, many recent studies have reported the discovery and functional characterization of functional neuronal CB2-Rs in the CNS beyond neuro-immuno cannabinoid activity.
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Affiliation(s)
- E S Onaivi
- William Paterson University, Wayne NJ and Molecular Neurobiology Branch, National Institute on Drug Abuse, NIH, Baltimore, USA
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Bello NT, Coughlin JW, Redgrave GW, Ladenheim EE, Moran TH, Guarda AS. Dietary conditions and highly palatable food access alter rat cannabinoid receptor expression and binding density. Physiol Behav 2011; 105:720-6. [PMID: 22005165 DOI: 10.1016/j.physbeh.2011.09.021] [Citation(s) in RCA: 27] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/21/2011] [Revised: 09/15/2011] [Accepted: 09/29/2011] [Indexed: 11/29/2022]
Abstract
Endogenous cannabinoid signaling, mediated predominately by CB1 receptor activation, is involved in food intake control and body weight regulation. Despite advances in determining the role of the CB1 receptor in obesity, its involvement in the driven nature of eating pathologies has received little attention. The present study examined CB1 receptor alterations as a consequence of dietary-induced binge eating in female Sprague Dawley rats. Four control groups were used to control for calorie restriction and highly palatable food variables characterizing this behavioral model. All groups were kept on their respective feeding schedules for 6-weeks and were given a uniform 33% calorie restriction (~22 h food deprivation) prior to sacrifice. Our findings indicate that regional CB1 mRNA and density were influenced by dietary conditions, but were not specific to the dietary-induced binge eating paradigm used. An increase of approximately 50% (compared with naive controls) in CB1 receptor mRNA levels in the nucleus of the solitary tract as measured by in situ hybridization was found in animals receiving continuous access to a highly palatable food (i.e., vegetable shortening with 10% sucrose). This group also had a significant increase in body weight and adiposity. An approximate 20% reduction in CB1 mRNA was observed in the cingulate cortex (areas 1 and 2) in animals exposed to an intermittent schedule of feeding, compared with groups that had ad libitum feeding schedules (i.e., continuous access and naive controls). Receptor density as measured by [(3)H]CP55,940 autoradiography, was reduced by approximately 30% in the nucleus accumbens shell region in groups receiving repeated access to the highly palatable food. Taken together, these findings indicate that dietary conditions can differentially influence CB1 receptors in forebrain and hindbrain regions.
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Affiliation(s)
- Nicholas T Bello
- Department of Animal Sciences, Rutgers, The State University of New Jersey, New Brunswick, NJ 08901, USA.
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25
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Sitkoff DF, Lee N, Ellsworth BA, Huang Q, Kang L, Baska R, Huang Y, Sun C, Pendri A, Malley MF, Scaringe RP, Gougoutas JZ, Reggio PH, Ewing WR, Pelleymounter MA, Carlson KE. Cannabinoid CB(1) receptor ligand binding and function examined through mutagenesis studies of F200 and S383. Eur J Pharmacol 2010; 651:9-17. [PMID: 21044623 DOI: 10.1016/j.ejphar.2010.10.056] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/19/2010] [Revised: 10/05/2010] [Accepted: 10/16/2010] [Indexed: 11/15/2022]
Abstract
The cannabinoid CB(1) G protein-coupled receptor has been shown to be a regulator of food consumption and has been studied extensively as a drug target for the treatment of obesity. To advance understanding of the receptor's three-dimensional structure, we performed mutagenesis studies at human cannabinoid CB(1) receptor residues F200 and S383 and measured changes in activity and binding affinity of compounds from two recently discovered active chemotypes, arylsulfonamide agonists and tetrahydroquinoline-based inverse agonists, as well as literature compounds. Our results add support to previous findings that both agonists and inverse agonists show varied patterns of binding at the two mutated residue sites, suggesting multiple subsites for binding to the cannabinoid CB(1) receptor for both functional types of ligands. We additionally find that an F200L mutation in the receptor largely restores binding affinity to ligands and significantly decreases constitutive activity when compared to F200A, resulting in a receptor phenotype that is closer to the wild-type receptor. The results downplay the importance of aromatic stacking interactions at F200 and suggest that a bulky hydrophobic contact is largely sufficient to provide significant receptor function and binding affinity to cannabinoid CB(1) receptor ligands.
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Affiliation(s)
- Doree F Sitkoff
- Research and Development, Bristol-Myers Squibb Company, Princeton, NJ 08543-5400, USA.
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26
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Carter GT, Abood ME, Aggarwal SK, Weiss MD. Cannabis and Amyotrophic Lateral Sclerosis: Hypothetical and Practical Applications, and a Call for Clinical Trials. Am J Hosp Palliat Care 2010; 27:347-56. [DOI: 10.1177/1049909110369531] [Citation(s) in RCA: 39] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/14/2022] Open
Abstract
Significant advances have increased our understanding of the molecular mechanisms of amyotrophic lateral sclerosis (ALS), yet this has not translated into any greatly effective therapies. It appears that a number of abnormal physiological processes occur simultaneously in this devastating disease. Ideally, a multidrug regimen, including glutamate antagonists, antioxidants, a centrally acting anti-inflammatory agent, microglial cell modulators (including tumor necrosis factor alpha [TNF-α] inhibitors), an antiapoptotic agent, 1 or more neurotrophic growth factors, and a mitochondrial function-enhancing agent would be required to comprehensively address the known pathophysiology of ALS. Remarkably, cannabis appears to have activity in all of those areas. Preclinical data indicate that cannabis has powerful antioxidative, anti-inflammatory, and neuroprotective effects. In the G93A-SOD1 ALS mouse, this has translated to prolonged neuronal cell survival, delayed onset, and slower progression of the disease. Cannabis also has properties applicable to symptom management of ALS, including analgesia, muscle relaxation, bronchodilation, saliva reduction, appetite stimulation, and sleep induction. With respect to the treatment of ALS, from both a disease modifying and symptom management viewpoint, clinical trials with cannabis are the next logical step. Based on the currently available scientific data, it is reasonable to think that cannabis might significantly slow the progression of ALS, potentially extending life expectancy and substantially reducing the overall burden of the disease.
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Affiliation(s)
- Gregory T. Carter
- Muscular Dystrophy Association/Amyotrophic Lateral Sclerosis Center, University of Washington Medical Center, Seattle, WA, USA,
| | - Mary E. Abood
- Anatomy and Cell Biology and Center for Substance Abuse Research, Temple University, Philadelphia, PA, USA
| | - Sunil K. Aggarwal
- Medical Scientist Training Program, School of Medicine, University of Washington, Seattle, WA, USA
| | - Michael D. Weiss
- Muscular Dystrophy Association/Amyotrophic Lateral Sclerosis Center, University of Washington Medical Center, Seattle, WA, USA, Neuromuscular Disease Division, Department of Neurology, University of Washington Medical Center, Seattle, WA, USA, Electrodiagnostic Laboratory, University of Washington Medical Center, Seattle, WA, USA
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27
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Freimuth N, Ramer R, Hinz B. Antitumorigenic effects of cannabinoids beyond apoptosis. J Pharmacol Exp Ther 2009; 332:336-44. [PMID: 19889794 DOI: 10.1124/jpet.109.157735] [Citation(s) in RCA: 51] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/06/2023] Open
Abstract
According to the World Health Organization, the cases of death caused by cancer will have been doubled until the year 2030. By 2010, cancer is expected to be the number one cause of death. Therefore, it is necessary to explore novel approaches for the treatment of cancer. Over past years, the antitumorigenic effects of cannabinoids have emerged as an exciting field in cancer research. Apart from their proapoptotic and antiproliferative action, recent research has shown that cannabinoids may likewise affect tumor cell angiogenesis, migration, invasion, adhesion, and metastasization. This review will summarize the data concerning the influence of cannabinoids on these locomotive processes beyond modulation of cancer cell apoptosis and proliferation. The findings discussed here provide a new perspective on the antitumorigenic potential of cannabinoids.
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Affiliation(s)
- Nadine Freimuth
- Institute of Toxicology and Pharmacology, University of Rostock, Rostock, Germany
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28
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Liu QR, Pan CH, Hishimoto A, Li CY, Xi ZX, Llorente-Berzal A, Viveros MP, Ishiguro H, Arinami T, Onaivi ES, Uhl GR. Species differences in cannabinoid receptor 2 (CNR2 gene): identification of novel human and rodent CB2 isoforms, differential tissue expression and regulation by cannabinoid receptor ligands. GENES BRAIN AND BEHAVIOR 2009; 8:519-30. [PMID: 19496827 DOI: 10.1111/j.1601-183x.2009.00498.x] [Citation(s) in RCA: 189] [Impact Index Per Article: 12.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
Cannabinoids, endocannabinoids and marijuana activate two well-characterized cannabinoid receptors (CB-Rs), CB1-Rs and CB2-Rs. The expression of CB1-Rs in the brain and periphery has been well studied, but neuronal CB2-Rs have received much less attention than CB1-Rs. Many studies have now identified and characterized functional glial and neuronal CB2-Rs in the central nervous system. However, many features of CB2-R gene structure, regulation and variation remain poorly characterized in comparison with the CB1-R. In this study, we report on the discovery of a novel human CB2 gene promoter transcribing testis (CB2A) isoform with starting exon located ca 45 kb upstream from the previously identified promoter transcribing the spleen isoform (CB2B). The 5' exons of both CB2 isoforms are untranslated 5'UTRs and alternatively spliced to the major protein coding exon of the CB2 gene. CB2A is expressed higher in testis and brain than CB2B that is expressed higher in other peripheral tissues than CB2A. Species comparison found that the CB2 gene of human, rat and mouse genomes deviated in their gene structures and isoform expression patterns. mCB2A expression was increased significantly in the cerebellum of mice treated with the CB-R mixed agonist, WIN55212-2. These results provide much improved information about CB2 gene structure and its human and rodent variants that should be considered in developing CB2-R-based therapeutic agents.
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Affiliation(s)
- Q-R Liu
- Mol. Neurobiol. Branch, NIDA-IRP, NIH, Baltimore, MD, USA
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29
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Zheng D, Bode AM, Zhao Q, Cho YY, Zhu F, Ma WY, Dong Z. The cannabinoid receptors are required for ultraviolet-induced inflammation and skin cancer development. Cancer Res 2008; 68:3992-8. [PMID: 18483286 DOI: 10.1158/0008-5472.can-07-6594] [Citation(s) in RCA: 71] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/06/2023]
Abstract
Solar UV irradiation is an important carcinogen that leads to the development of skin cancer, which is the most common human cancer. However, the receptors that mediate UV-induced skin carcinogenesis have not yet been unequivocally identified. Here we showed that UV irradiation directly activates cannabinoid receptors 1 and 2 (CB1/2). Notably, our data indicated that the absence of the CB1/2 receptors in mice results in a dramatic resistance to UVB-induced inflammation and a marked decrease in UVB-induced skin carcinogenesis. A marked attenuation of UVB-induced activation of mitogen-activated protein kinases and nuclear factor- kappaB was associated with CB1/2 deficiency. These data provide direct evidence indicating that the CB1/2 receptors play a key role in UV-induced inflammation and skin cancer development.
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Affiliation(s)
- Duo Zheng
- Hormel Institute, University of Minnesota, Austin, Minnesota, USA.
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30
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The endocannabinoid system in cancer-potential therapeutic target? Semin Cancer Biol 2007; 18:176-89. [PMID: 18249558 DOI: 10.1016/j.semcancer.2007.12.008] [Citation(s) in RCA: 50] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/17/2007] [Accepted: 12/05/2007] [Indexed: 01/13/2023]
Abstract
Endogenous arachidonic acid metabolites with properties similar to compounds of Cannabis sativa Linnaeus, the so-called endocannabinoids, have effects on various types of cancer. Although endocannabinoids and synthetic cannabinoids may have pro-proliferative effects, predominantly inhibitory effects on tumor growth, angiogenesis, migration and metastasis have been described. Remarkably, these effects may be selective for the cancer cells, while normal cells and tissues are spared. Such apparent tumor cell selectivity makes the endocannabinoid system an attractive potential target for cancer therapy. In this review we discuss various means by which the endocannabinoid system may be targeted in cancer and the current knowledge considering the regulation of the endocannabinoid system in malignancy.
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Kapur A, Hurst DP, Fleischer D, Whitnell R, Thakur GA, Makriyannis A, Reggio PH, Abood ME. Mutation studies of Ser7.39 and Ser2.60 in the human CB1 cannabinoid receptor: evidence for a serine-induced bend in CB1 transmembrane helix 7. Mol Pharmacol 2007; 71:1512-24. [PMID: 17384224 DOI: 10.1124/mol.107.034645] [Citation(s) in RCA: 68] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022] Open
Abstract
Ligands of structurally diverse natures are able to bind at the CB(1) cannabinoid receptor, suggesting the existence of multiple binding sites on the receptor. Modeling studies have implicated Ser2.60(173) and Ser7.39(383) as possible interaction site(s) for CB(1) agonists. To test the importance of these residues for receptor recognition, recombinant human CB(1) receptors, stably expressed in human embryonic kidney 293 cells, were used to investigate the consequences of mutating Ser2.60 (to S2.60A) or Ser7.39 (to S7.39A) in radioligand binding and guanosine 5'-3-O-(thio)triphosphate functional assays. The S7.39A mutant resulted in a total ablation of [(3)H](-)-3-[2-hydroxyl-4-(1,1-dimethylheptyl)phenyl]-4-[3-hydroxylpropyl] cyclohexan-1-ol (CP55,940) high-affinity binding. However, [(3)H](R)-(+)-[2,3-dihydro-5-methyl-3-[(4-morpholinyl)methyl]-pyrrolo[1,2,3-de]-1,4-benzoxazin-6-yl](1-naphthalenyl)methanone (WIN55,212-2) binding properties at S7.39A were comparable with those of the wild-type (WT) receptor. The binding affinity of (-)-11beta-hydroxy-3-(1',1'-dimethylheptyl)hexahydrocannabinol (AM4056) and (-)-11-hydroxydimethylheptyl-Delta(8)-tetrahydrocannabinol (HU210) were drastically reduced (50- to 100-fold) at the S7.39A mutant. Likewise, the EC(50) for HU210 and AM4056-mediated activation of the S7.39A receptor was increased by >200-fold. In contrast, the binding affinity and potency of WIN55,212-2, CP55,940, HU210, and AM4056 were unaltered at the S2.60A mutant compared with WT human CB(1) receptors. These results clearly suggest that Ser7.39, but not Ser2.60, plays a crucial role in mediating ligand specific interactions for CP55,940, HU210, and AM4056 at the human CB(1) receptor. Our modeling studies predict that Ser7.39 in a g-chi1 conformation may induce a helix bend in TMH7 that provides docking space for CP55,940 binding; the S7.39A mutation may alter this binding space, precluding CP55,940 binding.
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Affiliation(s)
- Ankur Kapur
- California Pacific Medical Center Research Institute, San Francisco, CA 94107, USA
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Freiman I, Anton A, Monyer H, Urbanski MJ, Szabo B. Analysis of the effects of cannabinoids on identified synaptic connections in the caudate-putamen by paired recordings in transgenic mice. J Physiol 2006; 575:789-806. [PMID: 16825300 PMCID: PMC1995699 DOI: 10.1113/jphysiol.2006.114272] [Citation(s) in RCA: 44] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/28/2022] Open
Abstract
CB(1) cannabinoid receptors are expressed in many neurons in the caudate-putamen. However, it is not known how the activation of these receptors influences synaptic transmission between different neuron classes. The aim was to establish a method for studying identified synaptic connections in the caudate-putamen, and to determine the effects of cannabinoids on these connections. Brain slices were prepared from transgenic mice expressing enhanced green fluorescent protein (EGFP) in parvalbumin-positive fast spiking interneurons (PV-FSNs). PV-FSNs were identified based on their fluorescence. Non-fluorescent medium-sized neurons were considered to be medium spiny neurons (MSNs). Synaptic transmission was studied by simultaneous patch-clamp recording from identified neuron pairs. In the case of PV-FSN --> MSN neurotransmission, the synthetic cannabinoid receptor agonist WIN55212-2 lowered the success rate of transmission and the amplitude of successful postsynaptic events. Analysis of miniature inhibitory postsynaptic currents indicated that WIN55212-2 inhibited synaptic transmission presynaptically. WIN55212-2 did not elicit somatodendritic effects in PV-FSNs: membrane potential, membrane current and evoked firing were not changed. WIN55212-2 also depressed the MSN --> MSN neurotransmission. The inhibitory synaptic input to MSNs was only weakly suppressed by endocannabinoids released by depolarized postsynaptic MSNs. The results show that the combined use of transgenic animals and paired-recording techniques allows the study of synaptic connections between rare neurons. Using these techniques, we showed that activation of CB(1) receptors on axon terminals of (i) PV-FSNs and (ii) MSNs leads to presynaptic inhibition of GABAergic synaptic transmission between these axons and their postsynaptic targets, the MSNs. The cannabinoids acted preferentially on axon terminals without effects on the somatodendritic region of the neurons.
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Affiliation(s)
- Ilka Freiman
- Institut für Experimentelle und Klinische Pharmakologie und Toxikologie, Albert-Ludwigs-Universität, D-79104 Freiburg i. Br., Germany
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33
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Engler B, Freiman I, Urbanski M, Szabo B. Effects of Exogenous and Endogenous Cannabinoids on GABAergic Neurotransmission between the Caudate-Putamen and the Globus Pallidus in the Mouse. J Pharmacol Exp Ther 2005; 316:608-17. [PMID: 16214880 DOI: 10.1124/jpet.105.092718] [Citation(s) in RCA: 48] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022] Open
Abstract
Globus pallidus neurons receive GABAergic input from the caudate-putamen via the striatopallidal pathway. Anatomical studies indicate that many CB(1) cannabinoid receptors are localized on terminals of striatopallidal axons. Accordingly, the hypothesis of the present work was that activation of CB(1) receptors presynaptically inhibits neurotransmission between striatopallidal axons and globus pallidus neurons. In sagittal mouse brain slices, striatopallidal axons were electrically stimulated in the caudate-putamen, and the resulting GABAergic inhibitory postsynaptic currents (IPSCs) were recorded in globus pallidus neurons. The synthetic cannabinoid receptor agonists R(+)-[2,3-dihydro-5-methyl-3-[(morpholinyl)methyl] pyrrolo[1,2,3-de]-1,4-benzoxazinyl]-(1-naphthalenyl)-methanone mesylate (WIN55212-2) and (-)-cis-3-[2-hydroxy-4-(1,1-dimethylheptyl)-phenyl]-trans-4-(3-hydroxy-propyl)-cyclohexanol (CP55940) decreased the amplitude of IPSCs. The CB(1) receptor antagonist rimonabant prevented the inhibition by WIN55212-2, pointing to involvement of CB(1) receptors. Depolarization of globus pallidus neurons induced a weak and short-lasting suppression of IPSCs [i.e., depolarization-induced suppression of inhibition (DSI) occurred]. Prevention of DSI by rimonabant indicates that endocannabinoids released from the postsynaptic neurons acted on CB(1) receptors to suppress synaptic transmission. WIN55212-2 did not modify currents in globus pallidus neurons elicited by GABA released from its chemically bound ("caged") form by a flash pulse, suggesting that WIN55212-2 depressed neurotransmission presynaptically. For studying the mechanism of the inhibition of GABA release, terminals of striatopallidal axons were labeled with a calcium-sensitive fluorescent dye. WIN55212-2 depressed the action potential-evoked increase in axon terminal calcium concentration. The results show that activation of CB(1) receptors by exogenous and endogenous cannabinoids leads to presynaptic inhibition of neurotransmission between striatopallidal axons and globus pallidus neurons. Depression of the action potential-evoked calcium influx into axon terminals is the probable mechanism of this inhibition.
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Affiliation(s)
- Birgit Engler
- Institut für Experimentelle und Klinische Pharmakologie und Toxikologie, Albert-Ludwigs-Universität, Freiburg, Germany
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