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Singh S, Sarroza D, English A, Whittington D, Dong A, Malamas M, Makriyannis A, van der Stelt M, Li Y, Zweifel L, Bruchas MR, Land BB, Stella N. P2X 7 receptor-dependent increase in endocannabinoid 2-arachidonoyl glycerol production by neuronal cells in culture: Dynamics and mechanism. Br J Pharmacol 2024; 181:2459-2477. [PMID: 38581262 DOI: 10.1111/bph.16348] [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: 07/07/2023] [Revised: 01/12/2024] [Accepted: 02/01/2024] [Indexed: 04/08/2024] Open
Abstract
BACKGROUND AND PURPOSE Neurotransmission and neuroinflammation are controlled by local increases in both extracellular ATP and the endocannabinoid 2-arachidonoyl glycerol (2-AG). While it is known that extracellular ATP stimulates 2-AG production in cells in culture, the dynamics and molecular mechanisms that underlie this response remain poorly understood. Detection of real-time changes in eCB levels with the genetically encoded sensor, GRABeCB2.0, can address this shortfall. EXPERIMENTAL APPROACH 2-AG and arachidonoylethanolamide (AEA) levels in Neuro2a (N2a) cells were measured by LC-MS, and GRABeCB2.0 fluorescence changes were detected using live-cell confocal microscopy and a 96-well fluorescence plate reader. KEY RESULTS 2-AG and AEA increased GRABeCB2.0 fluorescence in N2a cells with EC50 values of 81 and 58 nM, respectively; both responses were reduced by the cannabinoid receptor type 1 (CB1R) antagonist SR141617 and absent in cells expressing the mutant-GRABeCB2.0. ATP increased only 2-AG levels in N2a cells, as measured by LC-MS, and induced a transient increase in the GRABeCB2.0 signal within minutes primarily via activation of P2X7 receptors (P2X7R). This response was dependent on diacylglycerol lipase β activity, partially dependent on extracellular calcium and phospholipase C activity, but not controlled by the 2-AG hydrolysing enzyme, α/β-hydrolase domain containing 6 (ABHD6). CONCLUSIONS AND IMPLICATIONS Considering that P2X7R activation increases 2-AG levels within minutes, our results show how these molecular components are mechanistically linked. The specific molecular components in these signalling systems represent potential therapeutic targets for the treatment of neurological diseases, such as chronic pain, that involve dysregulated neurotransmission and neuroinflammation.
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Affiliation(s)
- Simar Singh
- Department of Pharmacology, University of Washington, Seattle, Washington, USA
| | - Dennis Sarroza
- Department of Pharmacology, University of Washington, Seattle, Washington, USA
| | - Anthony English
- Department of Pharmacology, University of Washington, Seattle, Washington, USA
| | - Dale Whittington
- Department of Medicinal Chemistry, University of Washington, Seattle, Washington, USA
| | - Ao Dong
- Peking University School of Life Sciences, PKU-IDG/McGovern Institute for Brain Research, Peking-Tsinghua Center for Life Sciences, Academy for Advanced Interdisciplinary Studies, Peking University, Beijing, China
| | - Michael Malamas
- Center for Drug Discovery and Departments of Chemistry and Chemical Biology and Pharmaceutical Sciences, Northeastern University, Boston, Massachusetts, USA
| | - Alexandros Makriyannis
- Center for Drug Discovery and Departments of Chemistry and Chemical Biology and Pharmaceutical Sciences, Northeastern University, Boston, Massachusetts, USA
| | | | - Yulong Li
- Peking University School of Life Sciences, PKU-IDG/McGovern Institute for Brain Research, Peking-Tsinghua Center for Life Sciences, Academy for Advanced Interdisciplinary Studies, Peking University, Beijing, China
| | - Larry Zweifel
- Department of Pharmacology, University of Washington, Seattle, Washington, USA
- Department of Psychiatry and Behavioral Sciences, University of Washington, Seattle, Washington, USA
- Center for Cannabis Research, University of Washington, Seattle, Washington, USA
- Center for the Neurobiology of Addiction, Pain, and Emotion, University of Washington, Seattle, Washington, USA
| | - Michael R Bruchas
- Department of Pharmacology, University of Washington, Seattle, Washington, USA
- Center for Cannabis Research, University of Washington, Seattle, Washington, USA
- Center for the Neurobiology of Addiction, Pain, and Emotion, University of Washington, Seattle, Washington, USA
- Department of Anesthesiology and Pain Medicine, University of Washington, Seattle, Washington, USA
| | - Benjamin B Land
- Department of Pharmacology, University of Washington, Seattle, Washington, USA
- Center for Cannabis Research, University of Washington, Seattle, Washington, USA
- Center for the Neurobiology of Addiction, Pain, and Emotion, University of Washington, Seattle, Washington, USA
| | - Nephi Stella
- Department of Pharmacology, University of Washington, Seattle, Washington, USA
- Department of Psychiatry and Behavioral Sciences, University of Washington, Seattle, Washington, USA
- Center for Cannabis Research, University of Washington, Seattle, Washington, USA
- Center for the Neurobiology of Addiction, Pain, and Emotion, University of Washington, Seattle, Washington, USA
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Aziz AI, Nguyen LC, Oumeslakht L, Bensussan A, Ben Mkaddem S. Cannabinoids as Immune System Modulators: Cannabidiol Potential Therapeutic Approaches and Limitations. Cannabis Cannabinoid Res 2022; 8:254-269. [PMID: 36413346 DOI: 10.1089/can.2022.0133] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/24/2022] Open
Abstract
Introduction: Cannabidiol (CBD) is the second most abundant Phytocannabinoid in Cannabis extracts. CBD has a binding affinity for several cannabinoid and cannabinoid-associated receptors. Epidiolex (oral CBD solution) has been lately licensed by the Food and Drug Administration (FDA) for the treatment of pediatric epileptic seizures. Methods: In this review, we discussed the most promising applications of CBD for chronic inflammatory conditions, namely CBD's anti-inflammatory effects during inflammatory bowel disease, coronavirus disease (antiviral effect), brain pathologies (neuroprotective and anti-inflammatory properties), as well as CBD immunomodulatory and antitumoral activities in the tumor microenvironment. Special focus was shed on the main therapeutic mechanisms of action of CBD, particularly in the control of the immune system and the endocannabinoid system. Results: Findings suggest that CBD is a potent immunomodulatory drug as it has manifested immunosuppressive properties in the context of sterile inflammation (e.g., inflammatory bowel disease, rheumatoid arthritis, and neurodegenerative diseases), and immunoprotective effects during viral infections (e.g. COVID-19) Similarly, CBD has exhibited a selective response toward cancer types by engaging different targets and signaling pathways. These results are in favor of the primary function of the endocannabinoid system which is homeostatic maintenance. Conclusion: The presented evidence suggests that the endocannabinoid system is a prominent target for the treatment of inflammatory and autoimmune diseases, rheumatoid diseases, viral infections, neurological and psychological pathologies, and cancer. Moreover, the antitumoral activities of CBD have been suggested to be potentially used in combination with chemo- or immunotherapy during cancer. However, clinical results are still lacking, which raises a challenge to apply translational cannabis research to the human immune system.
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Affiliation(s)
- Abdel-ilah Aziz
- Institute of Biological and Medical Sciences, Mohammed VI Polytechnic University, Ben Guerir, Morocco
| | - Long Chi Nguyen
- Ben May Department for Cancer Research, University of Chicago, Chicago, Illinois, USA
| | - Loubna Oumeslakht
- Institute of Biological and Medical Sciences, Mohammed VI Polytechnic University, Ben Guerir, Morocco
| | - Armand Bensussan
- Institute of Biological and Medical Sciences, Mohammed VI Polytechnic University, Ben Guerir, Morocco
- Onco-Dermatology and Therapies, INSERM UMRS976, Hôpital Saint Louis, Paris, France
| | - Sanae Ben Mkaddem
- Institute of Biological and Medical Sciences, Mohammed VI Polytechnic University, Ben Guerir, Morocco
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Manglani K, Dey CS. CDK5 inhibition improves glucose uptake in insulin-resistant neuronal cells via ERK1/2 pathway. Cell Biol Int 2021; 46:488-497. [PMID: 34865281 DOI: 10.1002/cbin.11735] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/18/2021] [Revised: 10/30/2021] [Accepted: 11/28/2021] [Indexed: 01/07/2023]
Abstract
Role of CDK5 and its inhibition in various neuronal processes and functions are well established. However, role of CDK5 and its inhibition in neuronal insulin-signaling and-resistance is not yet explored. In the present study, we investigated the effect of CDK5 inhibition in neuronal insulin signaling, specifically insulin-stimulated glucose uptake. CDK5 expression in neuro-2a cells was increased under insulin-resistant state, developed by chronic treatment of insulin, confirming the crucial role of CDK5 in insulin resistance in neuronal cells. However, whether increased expression of CDK5 in hyperinsulinemia-mediated insulin-resistant conditions is a cause or a consequence, is still an unanswered question. We showed that CDK5 inhibition did not affect basal insulin signaling; however, insulin-stimulated glucose uptake enhanced in insulin-resistant cells. Moreover, CDK5 inhibition could improve glucose uptake, the ultimate outcome of insulin signaling, in insulin-resistant neuro-2a cells. We first time showed that CDK5 inhibition by roscovitine could ameliorate insulin resistance and increase glucose uptake in neuronal cells via ERK1/2 pathway. Our study provides intriguing insights about the effect of CDK5 inhibition on neuronal insulin resistance and opens up a new paradigm to develop new therapeutic strategies for neuronal insulin resistance and associated pathophysiological conditions.
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Affiliation(s)
- Kapil Manglani
- Kusuma School of Biological Sciences, Indian Institute of Technology, Hauz Khas, New Delhi, India
| | - Chinmoy S Dey
- Kusuma School of Biological Sciences, Indian Institute of Technology, Hauz Khas, New Delhi, India
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Lo HF, Hong M, Szutorisz H, Hurd YL, Krauss RS. Δ9-Tetrahydrocannabinol inhibits Hedgehog-dependent patterning during development. Development 2021; 148:272342. [PMID: 34610637 DOI: 10.1242/dev.199585] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/03/2021] [Accepted: 08/23/2021] [Indexed: 12/20/2022]
Abstract
Many developmental disorders are thought to arise from an interaction between genetic and environmental risk factors. The Hedgehog (HH) signaling pathway regulates myriad developmental processes, and pathway inhibition is associated with birth defects, including holoprosencephaly (HPE). Cannabinoids are HH pathway inhibitors, but little is known of their effects on HH-dependent processes in mammalian embryos, and their mechanism of action is unclear. We report that the psychoactive cannabinoid Δ9-tetrahydrocannabinol (THC) induces two hallmark HH loss-of-function phenotypes (HPE and ventral neural tube patterning defects) in Cdon mutant mice, which have a subthreshold deficit in HH signaling. THC therefore acts as a 'conditional teratogen', dependent on a complementary but insufficient genetic insult. In vitro findings indicate that THC is a direct inhibitor of the essential HH signal transducer smoothened. The canonical THC receptor, cannabinoid receptor-type 1, is not required for THC to inhibit HH signaling. Cannabis consumption during pregnancy may contribute to a combination of risk factors underlying specific developmental disorders. These findings therefore have significant public health relevance.
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Affiliation(s)
- Hsiao-Fan Lo
- Department of Cell, Developmental, and Regenerative Biology, New York, NY 10029, USA
| | - Mingi Hong
- Department of Cell, Developmental, and Regenerative Biology, New York, NY 10029, USA
| | - Henrietta Szutorisz
- Addiction Institute and Departments of Psychiatry and Neuroscience, Icahn School of Medicine at Mount Sinai, New York, NY 10029, USA
| | - Yasmin L Hurd
- Addiction Institute and Departments of Psychiatry and Neuroscience, Icahn School of Medicine at Mount Sinai, New York, NY 10029, USA
| | - Robert S Krauss
- Department of Cell, Developmental, and Regenerative Biology, New York, NY 10029, USA
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Manning JJ, Green HM, Glass M, Finlay DB. Pharmacological selection of cannabinoid receptor effectors: Signalling, allosteric modulation and bias. Neuropharmacology 2021; 193:108611. [PMID: 34000272 DOI: 10.1016/j.neuropharm.2021.108611] [Citation(s) in RCA: 19] [Impact Index Per Article: 6.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/10/2020] [Revised: 04/26/2021] [Accepted: 05/10/2021] [Indexed: 12/14/2022]
Abstract
The type-1 cannabinoid receptor (CB1) is a promising drug target for a wide range of diseases. However, many existing and novel candidate ligands for CB1 have shown only limited therapeutic potential. Indeed, no ligands are currently approved for the clinic except formulations of the phytocannabinoids Δ9-THC and CBD and a small number of analogues. A key limitation of many promising CB1 ligands are their on-target adverse effects, notably including psychoactivity (agonists) and depression/suicidal ideation (inverse agonists). Recent drug development attempts have therefore focussed on altering CB1 signalling profiles in two ways. Firstly, with compounds that enhance or reduce the signalling of endogenous (endo-) cannabinoids, namely allosteric modulators. Secondly, with compounds that probe the capability of selectively targeting specific cellular signalling pathways that may mediate therapeutic effects using biased ligands. This review will summarise the current paradigm of CB1 signalling in terms of the intracellular transduction pathways acted on by the receptor. The development of compounds that selectively activate CB1 signalling pathways, whether allosterically or via orthosteric agonist bias, will also be addressed.
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Affiliation(s)
- Jamie J Manning
- Department of Pharmacology and Toxicology, University of Otago, Dunedin, New Zealand, PO Box 56, Dunedin, 9054, New Zealand
| | - Hayley M Green
- Department of Pharmacology and Toxicology, University of Otago, Dunedin, New Zealand, PO Box 56, Dunedin, 9054, New Zealand
| | - Michelle Glass
- Department of Pharmacology and Toxicology, University of Otago, Dunedin, New Zealand, PO Box 56, Dunedin, 9054, New Zealand
| | - David B Finlay
- Department of Pharmacology and Toxicology, University of Otago, Dunedin, New Zealand, PO Box 56, Dunedin, 9054, New Zealand.
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Haspula D, Clark MA. Cannabinoid Receptors: An Update on Cell Signaling, Pathophysiological Roles and Therapeutic Opportunities in Neurological, Cardiovascular, and Inflammatory Diseases. Int J Mol Sci 2020; 21:E7693. [PMID: 33080916 PMCID: PMC7590033 DOI: 10.3390/ijms21207693] [Citation(s) in RCA: 63] [Impact Index Per Article: 15.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/26/2020] [Revised: 10/14/2020] [Accepted: 10/15/2020] [Indexed: 12/16/2022] Open
Abstract
The identification of the human cannabinoid receptors and their roles in health and disease, has been one of the most significant biochemical and pharmacological advancements to have occurred in the past few decades. In spite of the major strides made in furthering endocannabinoid research, therapeutic exploitation of the endocannabinoid system has often been a challenging task. An impaired endocannabinoid tone often manifests as changes in expression and/or functions of type 1 and/or type 2 cannabinoid receptors. It becomes important to understand how alterations in cannabinoid receptor cellular signaling can lead to disruptions in major physiological and biological functions, as they are often associated with the pathogenesis of several neurological, cardiovascular, metabolic, and inflammatory diseases. This review focusses mostly on the pathophysiological roles of type 1 and type 2 cannabinoid receptors, and it attempts to integrate both cellular and physiological functions of the cannabinoid receptors. Apart from an updated review of pre-clinical and clinical studies, the adequacy/inadequacy of cannabinoid-based therapeutics in various pathological conditions is also highlighted. Finally, alternative strategies to modulate endocannabinoid tone, and future directions are also emphasized.
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Affiliation(s)
- Dhanush Haspula
- Molecular Signaling Section, Laboratory of Bioorganic Chemistry, National Institute of Diabetes and Digestive and Kidney Diseases, Bethesda, MD 20892, USA;
| | - Michelle A. Clark
- Department of Pharmaceutical Sciences, College of Pharmacy, Nova Southeastern University, Fort Lauderdale, FL 33314, USA
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Hicks SD, Jacob P, Perez O, Baffuto M, Gagnon Z, Middleton FA. The Transcriptional Signature of a Runner's High. Med Sci Sports Exerc 2019; 51:970-978. [PMID: 30557194 DOI: 10.1249/mss.0000000000001865] [Citation(s) in RCA: 23] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/01/2023]
Abstract
INTRODUCTION Endorphins, endocannabinoids, monoamines, and neurotrophins have all been implicated in the euphoric response to endurance running, known as a runner's high (RH). The epitranscriptional mechanisms regulating this effect have not been defined. Here, we investigate peripheral micro-ribonucleic acid (miRNA) changes unique to athletes experiencing postrun euphoria, yielding insights into gene networks that control an RH. METHODS A cohort study involving 25 collegiate runners (48% females, age = 20 ± 1 yr) examined salivary RNA levels before and after a long-distance run. Participants were divided into RH and nonrunner's high (NRH) groups based on surveys of four criteria (mood, lost sense of time, run quality, and euphoria). Physiological measures were also recorded (temperature, heart rate, blood pressure, pupillary dilatation, and salivary serotonin). Levels of miRNAs and their messenger RNA targets were compared across pre- and postrun samples from RH and NRH groups with two-way ANOVA. Representation of opioid, gamma-aminobutyic acid (GABA), endocannabinoid, neurotrophin, serotonergic, and dopaminergic pathways was assessed in DIANA miRPath. Pearson's correlation analyses examined relationships between miRNAs and RH indices. RESULTS RH participants (n = 13) demonstrated postrun mydriasis (P = 0.046) and hypothermia (P = 0.043) relative to NRH participants (n = 12) but had no difference in serotonin dynamics (P = 0.88). Six miRNAs (miR-194-5p, miR-4676-3p, miR-4254, miR-4425, miR-1273-3p, miR-6743-5p) exhibited significant effects (false discovery rate P value < 0.05) across pre- or postrun and RH/NRH groups. These miRNAs displayed target enrichment for opioid (P = 2.74E-06) and GABA (P = 0.00016) pathways. miR-1237-3p levels were related with lost sense of time (R = 0.40). Mitogen-activated protein kinase (MAPK11), an endocannabinoid target of miR-1273-3p, was nominally elevated in RH participants (false discovery rate P value = 0.11). CONCLUSIONS Unique dynamics in miRNA concentration occur in athletes with subjective/objective evidence of RH, targeting genes implicated endorphin, endocannabinoid, and GABAergic signaling.
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Affiliation(s)
- Steven D Hicks
- Department of Pediatrics, Penn State College of Medicine, Hershey, PA
| | - Paige Jacob
- Department of Biology, Marist College, Poughkeepsie, NY
| | - Omar Perez
- Department of Biology, Marist College, Poughkeepsie, NY
| | | | - Zofia Gagnon
- Department of Biology, Marist College, Poughkeepsie, NY
| | - Frank A Middleton
- Departments of Neuroscience and Physiology, Biochemistry and Molecular Biology, Pediatrics, and Psychiatry and Behavioral Sciences, SUNY Upstate Medical University, Syracuse, NY
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Wouters E, Walraed J, Banister SD, Stove CP. Insights into biased signaling at cannabinoid receptors: synthetic cannabinoid receptor agonists. Biochem Pharmacol 2019; 169:113623. [DOI: 10.1016/j.bcp.2019.08.025] [Citation(s) in RCA: 51] [Impact Index Per Article: 10.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/21/2019] [Accepted: 08/26/2019] [Indexed: 01/09/2023]
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Saroz Y, Kho DT, Glass M, Graham ES, Grimsey NL. Cannabinoid Receptor 2 (CB 2) Signals via G-alpha-s and Induces IL-6 and IL-10 Cytokine Secretion in Human Primary Leukocytes. ACS Pharmacol Transl Sci 2019; 2:414-428. [PMID: 32259074 DOI: 10.1021/acsptsci.9b00049] [Citation(s) in RCA: 39] [Impact Index Per Article: 7.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/17/2019] [Indexed: 12/11/2022]
Abstract
Cannabinoid receptor 2 (CB2) is a promising therapeutic target for immunological modulation. There is, however, a deficit of knowledge regarding CB2 signaling and function in human primary immunocompetent cells. We applied an experimental paradigm which closely models the in situ state of human primary leukocytes (PBMC; peripheral blood mononuclear cells) to characterize activation of a number of signaling pathways in response to a CB2-selective ligand (HU308). We observed a "lag" phase of unchanged cAMP concentration prior to development of classically expected Gαi-mediated inhibition of cAMP synthesis. Application of G protein inhibitors revealed that this apparent lag was a result of counteraction of Gαi effects by concurrent Gαs activation. Monitoring downstream signaling events showed that activation of p38 was mediated by Gαi, whereas ERK1/2 and Akt phosphorylation were mediated by Gαi-coupled βγ. Activation of CREB integrated multiple components; Gαs and βγ mediated ∼85% of the response, while ∼15% was attributed to Gαi. Responses to HU308 had an important functional outcome-secretion of interleukins 6 (IL-6) and 10 (IL-10). IL-2, IL-4, IL-12, IL-13, IL-17A, MIP-1α, and TNF-α were unaffected. IL-6/IL-10 induction had a similar G protein coupling profile to CREB activation. All response potencies were consistent with that expected for HU308 acting via CB2. Additionally, signaling and functional effects were completely blocked by a CB2-selective inverse agonist, giving additional evidence for CB2 involvement. This work expands the current paradigm regarding cannabinoid immunomodulation and reinforces the potential utility of CB2 ligands as immunomodulatory therapeutics.
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Affiliation(s)
- Yurii Saroz
- Department of Pharmacology and Clinical Pharmacology, School of Medical Sciences, Faculty of Medical and Health Sciences, Centre for Brain Research, Faculty of Medical and Health Sciences, and Department of Molecular Medicine and Pathology, School of Medical Sciences, Faculty of Medical and Health Sciences, University of Auckland, 85 Park Road, Grafton, Auckland, 1023, New Zealand.,Department of Pharmacology and Clinical Pharmacology, School of Medical Sciences, Faculty of Medical and Health Sciences, Centre for Brain Research, Faculty of Medical and Health Sciences, and Department of Molecular Medicine and Pathology, School of Medical Sciences, Faculty of Medical and Health Sciences, University of Auckland, 85 Park Road, Grafton, Auckland, 1023, New Zealand
| | - Dan T Kho
- Department of Pharmacology and Clinical Pharmacology, School of Medical Sciences, Faculty of Medical and Health Sciences, Centre for Brain Research, Faculty of Medical and Health Sciences, and Department of Molecular Medicine and Pathology, School of Medical Sciences, Faculty of Medical and Health Sciences, University of Auckland, 85 Park Road, Grafton, Auckland, 1023, New Zealand.,Department of Pharmacology and Clinical Pharmacology, School of Medical Sciences, Faculty of Medical and Health Sciences, Centre for Brain Research, Faculty of Medical and Health Sciences, and Department of Molecular Medicine and Pathology, School of Medical Sciences, Faculty of Medical and Health Sciences, University of Auckland, 85 Park Road, Grafton, Auckland, 1023, New Zealand
| | - Michelle Glass
- Department of Pharmacology and Toxicology, School of Biomedical Sciences, Division of Health Sciences, University of Otago, Dunedin, 9016, New Zealand
| | - Euan Scott Graham
- Department of Pharmacology and Clinical Pharmacology, School of Medical Sciences, Faculty of Medical and Health Sciences, Centre for Brain Research, Faculty of Medical and Health Sciences, and Department of Molecular Medicine and Pathology, School of Medical Sciences, Faculty of Medical and Health Sciences, University of Auckland, 85 Park Road, Grafton, Auckland, 1023, New Zealand.,Department of Pharmacology and Clinical Pharmacology, School of Medical Sciences, Faculty of Medical and Health Sciences, Centre for Brain Research, Faculty of Medical and Health Sciences, and Department of Molecular Medicine and Pathology, School of Medical Sciences, Faculty of Medical and Health Sciences, University of Auckland, 85 Park Road, Grafton, Auckland, 1023, New Zealand
| | - Natasha Lillia Grimsey
- Department of Pharmacology and Clinical Pharmacology, School of Medical Sciences, Faculty of Medical and Health Sciences, Centre for Brain Research, Faculty of Medical and Health Sciences, and Department of Molecular Medicine and Pathology, School of Medical Sciences, Faculty of Medical and Health Sciences, University of Auckland, 85 Park Road, Grafton, Auckland, 1023, New Zealand.,Department of Pharmacology and Clinical Pharmacology, School of Medical Sciences, Faculty of Medical and Health Sciences, Centre for Brain Research, Faculty of Medical and Health Sciences, and Department of Molecular Medicine and Pathology, School of Medical Sciences, Faculty of Medical and Health Sciences, University of Auckland, 85 Park Road, Grafton, Auckland, 1023, New Zealand
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Endocannabinoid System and Alcohol Abuse Disorders. ADVANCES IN EXPERIMENTAL MEDICINE AND BIOLOGY 2019; 1162:89-127. [PMID: 31332736 DOI: 10.1007/978-3-030-21737-2_6] [Citation(s) in RCA: 13] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/12/2022]
Abstract
Δ9-tetrahydrocannabinol (Δ9-THC), the primary active component in Cannabis sativa preparations such as hashish and marijuana, signals by binding to cell surface receptors. Two types of receptors have been cloned and characterized as cannabinoid (CB) receptors. CB1 receptors (CB1R) are ubiquitously present in the central nervous system (CNS) and are present in both inhibitory interneurons and excitatory neurons at the presynaptic terminal. CB2 receptors (CB2R) are demonstrated in microglial cells, astrocytes, and several neuron subpopulations and are present in both pre- and postsynaptic terminals. The majority of studies on these receptors have been conducted in the past two and half decades after the identification of the molecular constituents of the endocannabinoid (eCB) system that started with the characterization of CB1R. Subsequently, the seminal discovery was made, which suggested that alcohol (ethanol) alters the eCB system, thus establishing the contribution of the eCB system in the motivation to consume ethanol. Several preclinical studies have provided evidence that CB1R significantly contributes to the motivational and reinforcing properties of ethanol and that the chronic consumption of ethanol alters eCB transmitters and CB1R expression in the brain nuclei associated with addiction pathways. Additionally, recent seminal studies have further established the role of the eCB system in the development of ethanol-induced developmental disorders, such as fetal alcohol spectrum disorders (FASD). These results are augmented by in vitro and ex vivo studies, showing that acute and chronic treatment with ethanol produces physiologically relevant alterations in the function of the eCB system during development and in the adult stage. This chapter provides a current and comprehensive review of the literature concerning the role of the eCB system in alcohol abuse disorders (AUD).
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Jain R, Watson U, Vasudevan L, Saini DK. ERK Activation Pathways Downstream of GPCRs. INTERNATIONAL REVIEW OF CELL AND MOLECULAR BIOLOGY 2018; 338:79-109. [PMID: 29699693 DOI: 10.1016/bs.ircmb.2018.02.003] [Citation(s) in RCA: 42] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/27/2022]
Abstract
GPCRs, the 7-TM receptors, represent a class of cell surface receptors which modulate a variety of physiological responses. The serpentine structure in addition to contributing the diversity of stimuli these receptors can sense also provides flexibility to the extracellular and intracellular regions where other proteins can interact with and can form functionally active multimeric entities. The range in signaling and physiological responses generated by these receptors can be attributed to a large repertoire of the receptor subtypes as well as their differential coupling to various classes of G-protein subunits and other proteins which facilitate multistate activation. A multistate GPCR can engage diverse signaling molecules, thereby modulating not only the canonical cellular responses but also noncanonical responses typically associated with activation of other cascades such as RTK and MAPK/ERK signaling. Given the crucial involvement of MAP kinase/ERK signaling in cell fate determination specially with respect to regulating cell proliferation, cellular apoptosis, and survival, GPCR-mediated cross-activation of MAPK has been explored in various systems and shown to involve functional integration of multiple pathways. This review describes the present knowledge of the different mechanisms of ERK activation downstream of GPCRs and our present understanding of receptor-dependent and -independent MAPK activation cascades.
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Affiliation(s)
- Ruchi Jain
- Department of Molecular Reproduction, Development and Genetics, Indian Institute of Science, Bangalore, India
| | - Uchenna Watson
- Department of Molecular Reproduction, Development and Genetics, Indian Institute of Science, Bangalore, India; Department of Studies in Zoology, University of Mysore, Manasagangothri, Mysore, India
| | - Lakshmi Vasudevan
- Department of Molecular Reproduction, Development and Genetics, Indian Institute of Science, Bangalore, India; L-GEST-Laboratory of Toxicology, Faculty of Pharmaceutical Sciences, Ghent, Belgium
| | - Deepak K Saini
- Department of Molecular Reproduction, Development and Genetics, Indian Institute of Science, Bangalore, India; Centre for BioSystems Science and Engineering, Indian Institute of Science, Bangalore, India.
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Basavarajappa BS, Shivakumar M, Joshi V, Subbanna S. Endocannabinoid system in neurodegenerative disorders. J Neurochem 2017; 142:624-648. [PMID: 28608560 DOI: 10.1111/jnc.14098] [Citation(s) in RCA: 128] [Impact Index Per Article: 18.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/06/2017] [Revised: 05/22/2017] [Accepted: 06/02/2017] [Indexed: 12/19/2022]
Abstract
Most neurodegenerative disorders (NDDs) are characterized by cognitive impairment and other neurological defects. The definite cause of and pathways underlying the progression of these NDDs are not well-defined. Several mechanisms have been proposed to contribute to the development of NDDs. These mechanisms may proceed concurrently or successively, and they differ among cell types at different developmental stages in distinct brain regions. The endocannabinoid system, which involves cannabinoid receptors type 1 (CB1R) and type 2 (CB2R), endogenous cannabinoids and the enzymes that catabolize these compounds, has been shown to contribute to the development of NDDs in several animal models and human studies. In this review, we discuss the functions of the endocannabinoid system in NDDs and converse the therapeutic efficacy of targeting the endocannabinoid system to rescue NDDs.
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Affiliation(s)
- Balapal S Basavarajappa
- Division of Analytical Psychopharmacology, Nathan Kline Institute for Psychiatric Research, Orangeburg, New York, USA.,New York State Psychiatric Institute, New York City, New York, USA.,Department of Psychiatry, College of Physicians & Surgeons, Columbia University, New York City, New York, USA.,Department of Psychiatry, New York University Langone Medical Center, New York City, New York, USA
| | - Madhu Shivakumar
- Division of Analytical Psychopharmacology, Nathan Kline Institute for Psychiatric Research, Orangeburg, New York, USA
| | - Vikram Joshi
- Division of Analytical Psychopharmacology, Nathan Kline Institute for Psychiatric Research, Orangeburg, New York, USA
| | - Shivakumar Subbanna
- Division of Analytical Psychopharmacology, Nathan Kline Institute for Psychiatric Research, Orangeburg, New York, USA
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13
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Zheng T, Zhang T, Zhang R, Wang ZL, Han ZL, Li N, Li XH, Zhang MN, Xu B, Yang XL, Fang Q, Wang R. Pharmacological characterization of rat VD-hemopressin(α), an α-hemoglobin-derived peptide exhibiting cannabinoid agonist-like effects in mice. Neuropeptides 2017; 63:83-90. [PMID: 28010996 DOI: 10.1016/j.npep.2016.12.006] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 10/22/2016] [Revised: 12/08/2016] [Accepted: 12/14/2016] [Indexed: 12/30/2022]
Abstract
Hemopressin and related peptides have shown to function as the endogenous ligands or the regulator of cannabinoid receptors. Moreover, hemopressin and its truncated peptides were also reported to produce a slight modulatory effect on opioid system. In the present work, based on the amino acid sequence analyses of hemoglobin subunit α, rat VD-hemopressin(α) [(r)VD-Hpα] was predicted as a cannabinoid peptide derived from rat α-hemoglobin. Furthermore, (r)VD-Hpα was synthesized and characterized in a series of in vitro and in vivo assays. Our results demonstrated that (r)VD-Hpα induced neurite outgrowth in Neuro 2A cells via CB1 receptor. In the tail-flick assay, (r)VD-Hpα dose-dependently exerted central antinociception through CB1 receptor, but not CB2 and opioid receptors. In mice, supraspinal administration of (r)VD-Hpα produced dose-dependent hypothermia, which was partially reduced by the CB1 receptor antagonist AM251, but not by the antagonists of CB2 and opioid receptors. In addition, (r)VD-Hpα caused hypoactivity after intracerebroventricular injection, and this effect was insensitive to the antagonists of cannabinoid and opioid receptors. Further assessment of the side-effects demonstrated that (r)VD-Hpα evoked the limited effects on gastrointestinal transit at antinociceptive doses, but repeated i.c.v. injection of (r)VD-Hpα induced development of antinociceptive tolerance. Taken together, these data suggest that the predicted peptide (r)VD-Hpα produces antinociception, hypothermia and hypoactivity via different pharmacological mechanisms, at least partially, which may offer an attractive strategy for separating cannabinoid analgesia from hypoactivity. Moreover, it implies that (r)VD-Hpα has therapeutic potential in pain management with limited side-effects.
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Affiliation(s)
- Ting Zheng
- Key Laboratory of Preclinical Study for New Drugs of Gansu Province, Institute of Physiology, School of Basic Medical Sciences, Lanzhou University, 199 Donggang West Road, Lanzhou 730000, PR China
| | - Ting Zhang
- Key Laboratory of Preclinical Study for New Drugs of Gansu Province, Institute of Physiology, School of Basic Medical Sciences, Lanzhou University, 199 Donggang West Road, Lanzhou 730000, PR China
| | - Run Zhang
- Key Laboratory of Preclinical Study for New Drugs of Gansu Province, Institute of Physiology, School of Basic Medical Sciences, Lanzhou University, 199 Donggang West Road, Lanzhou 730000, PR China
| | - Zi-Long Wang
- Key Laboratory of Preclinical Study for New Drugs of Gansu Province, Institute of Physiology, School of Basic Medical Sciences, Lanzhou University, 199 Donggang West Road, Lanzhou 730000, PR China
| | - Zheng-Lan Han
- Key Laboratory of Preclinical Study for New Drugs of Gansu Province, Institute of Physiology, School of Basic Medical Sciences, Lanzhou University, 199 Donggang West Road, Lanzhou 730000, PR China
| | - Ning Li
- Key Laboratory of Preclinical Study for New Drugs of Gansu Province, Institute of Physiology, School of Basic Medical Sciences, Lanzhou University, 199 Donggang West Road, Lanzhou 730000, PR China
| | - Xu-Hui Li
- Key Laboratory of Preclinical Study for New Drugs of Gansu Province, Institute of Physiology, School of Basic Medical Sciences, Lanzhou University, 199 Donggang West Road, Lanzhou 730000, PR China
| | - Meng-Na Zhang
- Key Laboratory of Preclinical Study for New Drugs of Gansu Province, Institute of Physiology, School of Basic Medical Sciences, Lanzhou University, 199 Donggang West Road, Lanzhou 730000, PR China
| | - Biao Xu
- Key Laboratory of Preclinical Study for New Drugs of Gansu Province, Institute of Physiology, School of Basic Medical Sciences, Lanzhou University, 199 Donggang West Road, Lanzhou 730000, PR China
| | - Xiong-Li Yang
- Key Laboratory of Preclinical Study for New Drugs of Gansu Province, Institute of Physiology, School of Basic Medical Sciences, Lanzhou University, 199 Donggang West Road, Lanzhou 730000, PR China
| | - Quan Fang
- Key Laboratory of Preclinical Study for New Drugs of Gansu Province, Institute of Physiology, School of Basic Medical Sciences, Lanzhou University, 199 Donggang West Road, Lanzhou 730000, PR China.
| | - Rui Wang
- Key Laboratory of Preclinical Study for New Drugs of Gansu Province, Institute of Physiology, School of Basic Medical Sciences, Lanzhou University, 199 Donggang West Road, Lanzhou 730000, PR China.
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14
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Canazza I, Ossato A, Vincenzi F, Gregori A, Di Rosa F, Nigro F, Rimessi A, Pinton P, Varani K, Borea PA, Marti M. Pharmaco-toxicological effects of the novel third-generation fluorinate synthetic cannabinoids, 5F-ADBINACA, AB-FUBINACA, and STS-135 in mice. In vitro and in vivo studies. Hum Psychopharmacol 2017; 32. [PMID: 28597570 DOI: 10.1002/hup.2601] [Citation(s) in RCA: 33] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 10/07/2016] [Revised: 04/10/2017] [Accepted: 04/11/2017] [Indexed: 01/08/2023]
Abstract
INTRODUCTION 5F-ADBINACA, AB-FUBINACA, and STS-135 are 3 novel third-generation fluorinate synthetic cannabinoids that are illegally marketed as incense, herbal preparations, or research chemicals for their psychoactive cannabis-like effects. METHODS The present study aims at investigating the in vitro and in vivo pharmacological activity of 5F-ADBINACA, AB-FUBINACA, and STS-135 in male CD-1 mice, comparing their in vivo effects with those caused by the administration of Δ9 -THC and JWH-018. In vitro competition binding experiments revealed a nanomolar affinity and potency of the 5F-ADBINACA, AB-FUBINACA, and STS-135 on mouse and human CB1 and CB2 receptors. Moreover, these synthetic cannabinoids induced neurotoxicity in murine neuro-2a cells. RESULTS In vivo studies showed that 5F-ADBINACA, AB-FUBINACA, and STS-135 induced hypothermia; increased pain threshold to both noxious mechanical and thermal stimuli; caused catalepsy; reduced motor activity; impaired sensorimotor responses (visual, acoustic, and tactile); caused seizures, myoclonia, and hyperreflexia; and promoted aggressiveness in mice. Behavioral and neurological effects were fully prevented by the selective CB1 receptor antagonist/inverse agonist AM 251. Differently, the visual sensory response induced by STS-135 was only partly prevented by the AM 251, suggesting a CB1 -independent mechanism. CONCLUSIONS For the first time, the present study demonstrates the pharmaco-toxicological effects induced by the administration of 5F-ADBINACA, AB-FUBINACA, and STS-135 in mice and suggests their possible detrimental effects on human health.
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Affiliation(s)
- Isabella Canazza
- Department of Life Sciences and Biotechnology (SVeB), University of Ferrara, Ferrara, Italy.,Institute of Public Health, Section of Legal Medicine, Catholic University of Rome, Rome, Italy
| | - Andrea Ossato
- Department of Life Sciences and Biotechnology (SVeB), University of Ferrara, Ferrara, Italy.,Institute of Public Health, Section of Legal Medicine, Catholic University of Rome, Rome, Italy
| | - Fabrizio Vincenzi
- Department of Medical Sciences, University of Ferrara, Ferrara, Italy
| | - Adolfo Gregori
- Carabinieri, Department of Scientific Investigation (RIS), Rome, Italy
| | - Fabiana Di Rosa
- Carabinieri, Department of Scientific Investigation (RIS), Rome, Italy
| | - Federica Nigro
- Department of Morphology, Surgery and Experimental Medicine, Section of Pathology, Oncology and Experimental Biology, Laboratory for Technologies of Advanced Therapies (LTTA), University of Ferrara, Ferrara, Italy
| | - Alessandro Rimessi
- Department of Morphology, Surgery and Experimental Medicine, Section of Pathology, Oncology and Experimental Biology, Laboratory for Technologies of Advanced Therapies (LTTA), University of Ferrara, Ferrara, Italy
| | - Paolo Pinton
- Department of Morphology, Surgery and Experimental Medicine, Section of Pathology, Oncology and Experimental Biology, Laboratory for Technologies of Advanced Therapies (LTTA), University of Ferrara, Ferrara, Italy
| | - Katia Varani
- Department of Medical Sciences, University of Ferrara, Ferrara, Italy
| | - Pier Andrea Borea
- Department of Medical Sciences, University of Ferrara, Ferrara, Italy
| | - Matteo Marti
- Department of Life Sciences and Biotechnology (SVeB), University of Ferrara, Ferrara, Italy.,Center for Neuroscience and Istituto Nazionale di Neuroscienze, University of Ferrara, Ferrara, Italy
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15
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Cannabinoid CB1 and CB2 receptors differentially modulate L- and T-type Ca 2+ channels in rat retinal ganglion cells. Neuropharmacology 2017; 124:143-156. [PMID: 28431968 DOI: 10.1016/j.neuropharm.2017.04.027] [Citation(s) in RCA: 22] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/15/2016] [Revised: 03/15/2017] [Accepted: 04/17/2017] [Indexed: 01/09/2023]
Abstract
Endocannabinoid signaling system is involved in regulating multiple neuronal functions in the central nervous system by activating G-protein coupled cannabinoid CB1 and CB2 receptors (CB1Rs and CB2Rs). Growing evidence has shown that CB1Rs and CB2Rs are extensively expressed in retinal ganglion cells (RGCs). Here, modulation of L- and T-types Ca2+ channels by activating CB1Rs and CB2Rs in RGCs was investigated. Triple immunofluorescent staining showed that L-type subunit CaV1.2 was co-localized with T-type subunits (CaV3.1, CaV3.2 and CaV3.3) in rat RGCs. In acutely isolated rat RGCs, the CB1R agonist WIN55212-2 suppressed both peak and steady-state Ca2+ currents in a dose-dependent manner, with IC50 being 9.6 μM and 8.4 μM, respectively. It was further shown that activation of CB1Rs by WIN55212-2 or ACEA, another CB1R agonist, significantly suppressed both L- and T-type Ca2+ currents, and shifted inactivation curve of T-type one toward hyperpolarization direction. While the effect on L-type Ca2+ channels was mediated by intracellular cAMP/protein kinase A (PKA), mitogen-activated protein kinase (MAPK)/extracellular signal-regulated kinase (ERK) and calcium/calmodulin-dependent protein kinase II (CaMKII) signaling pathways, only CaMKII signaling pathway was involved in the effect on T-type Ca2+ channels. Furthermore, CB65 and HU308, two specific CB2R agonists, significantly suppressed T-type Ca2+ channels, which was mediated by intracellular cAMP/PKA and CaMKII signaling pathways, but had no effect on L-type channels. These results imply that endogenous cannabinoids may modulate the excitability and the output of RGCs by differentially suppressing the activity of L- and T-type Ca2+ channels through activation of CB1Rs and CB2Rs. This article is part of the Special Issue entitled "A New Dawn in Cannabinoid Neurobiology".
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16
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Abstract
An agonist that acts through a single receptor can activate numerous signaling pathways. Recent studies have suggested that different ligands can differentially activate these pathways by stabilizing a limited range of receptor conformations, which in turn preferentially drive different downstream signaling cascades. This concept, termed "biased signaling" represents an exciting therapeutic opportunity to target specific pathways that elicit only desired effects, while avoiding undesired effects mediated by different signaling cascades. The cannabinoid receptors CB1 and CB2 each activate multiple pathways, and evidence is emerging for bias within these pathways. This review will summarize the current evidence for biased signaling through cannabinoid receptor subtypes CB1 and CB2.
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Affiliation(s)
- Mikkel Søes Ibsen
- Department of Pharmacology, School of Medical Sciences, University of Auckland, Auckland, New Zealand
| | - Mark Connor
- Department of Biomedical Sciences, Faculty of Medicine and Health Sciences, 2 Technology Place, Macquarie University, New South Wales, Australia
| | - Michelle Glass
- Department of Pharmacology, School of Medical Sciences, University of Auckland, Auckland, New Zealand
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17
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Priestley R, Glass M, Kendall D. Functional Selectivity at Cannabinoid Receptors. CANNABINOID PHARMACOLOGY 2017; 80:207-221. [DOI: 10.1016/bs.apha.2017.03.005] [Citation(s) in RCA: 21] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/13/2022]
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18
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Zou S, Somvanshi RK, Kumar U. Somatostatin receptor 5 is a prominent regulator of signaling pathways in cells with coexpression of Cannabinoid receptors 1. Neuroscience 2016; 340:218-231. [PMID: 27984180 DOI: 10.1016/j.neuroscience.2016.10.056] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/28/2016] [Revised: 10/20/2016] [Accepted: 10/22/2016] [Indexed: 11/30/2022]
Abstract
Endocannabinoids and somatostatin (SST) play critical roles in several pathophysiological conditions via binding to different receptor subtypes. Cannabinoid receptor 1 (CB1R) and somatostatin receptors (SSTRs) are expressed in several brain regions and share overlapping functions. Whether these two prominent members of G-protein-coupled receptor (GPCR) family interact with each other and constitute a functional receptor complex is not known. In the present study, we investigated the colocalization of CB1R and SSTR5 in rat brain, and studied receptor internalization, interaction and signal transduction pathways in HEK-293 cells cotransfected with human cannabinoid receptor 1 (hCB1R) and hSSTR5. Our results showed that CB1R and SSTR5 colocalized in rat brain cortex, striatum, and hippocampus. CB1R was expressed in SSTR5 immunoprecipitate prepared from the brain tissue lysate, indicating their association in a system where these receptors are endogenously expressed. In cotransfected HEK-293 cells, SSTR5 and CB1R existed in a constitutive heteromeric complex under basal condition, which was disrupted upon agonist treatments. Furthermore, concurrent receptor activation led to preferential formation of SSTR5 homodimer and dissociation of CB1R homodimer. We also discovered that second messenger cyclic adenosine monophosphate and downstream signaling pathways were modulated in a SSTR5-dominant and concentration-dependent manner in the presence of receptor-specific agonist. In conclusion, with predominant role of SSTR5, the functional consequences of crosstalk between SSTR5 and CB1R resulting in the regulation of receptor trafficking and signal transduction pathways open new therapeutic avenue in cancer biology and excitotoxicity.
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Affiliation(s)
- Shenglong Zou
- Faculty of Pharmaceutical Sciences, The University of British Columbia, Vancouver, BC, Canada
| | - Rishi K Somvanshi
- Faculty of Pharmaceutical Sciences, The University of British Columbia, Vancouver, BC, Canada
| | - Ujendra Kumar
- Faculty of Pharmaceutical Sciences, The University of British Columbia, Vancouver, BC, Canada.
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19
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Wardman JH, Gomes I, Bobeck EN, Stockert JA, Kapoor A, Bisignano P, Gupta A, Mezei M, Kumar S, Filizola M, Devi LA. Identification of a small-molecule ligand that activates the neuropeptide receptor GPR171 and increases food intake. Sci Signal 2016; 9:ra55. [PMID: 27245612 DOI: 10.1126/scisignal.aac8035] [Citation(s) in RCA: 23] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/21/2023]
Abstract
Several neuropeptide systems in the hypothalamus, including neuropeptide Y and agouti-related protein (AgRP), control food intake. Peptides derived from proSAAS, a precursor implicated in the regulation of body weight, also control food intake. GPR171 is a heterotrimeric guanine nucleotide-binding protein (G protein)-coupled receptor (GPCR) for BigLEN (b-LEN), a peptide derived from proSAAS. To facilitate studies exploring the physiological role of GPR171, we sought to identify small-molecule ligands for this receptor by performing a virtual screen of a compound library for interaction with a homology model of GPR171. We identified MS0015203 as an agonist of GPR171 and demonstrated the selectivity of MS0015203 for GPR171 by testing the binding of this compound to 80 other membrane proteins, including family A GPCRs. Reducing the expression of GPR171 by shRNA (short hairpin RNA)-mediated knockdown blunted the cellular and tissue response to MS0015203. Peripheral injection of MS0015203 into mice increased food intake and body weight, and these responses were significantly attenuated in mice with decreased expression of GPR171 in the hypothalamus. Together, these results suggest that MS0015203 is a useful tool to probe the pharmacological and functional properties of GPR171 and that ligands targeting GPR171 may eventually lead to therapeutics for food-related disorders.
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Affiliation(s)
- Jonathan H Wardman
- Department of Pharmacology and Systems Therapeutics, Icahn School of Medicine at Mount Sinai, New York, NY 10029, USA
| | - Ivone Gomes
- Department of Pharmacology and Systems Therapeutics, Icahn School of Medicine at Mount Sinai, New York, NY 10029, USA
| | - Erin N Bobeck
- Department of Pharmacology and Systems Therapeutics, Icahn School of Medicine at Mount Sinai, New York, NY 10029, USA
| | - Jennifer A Stockert
- Department of Pharmacology and Systems Therapeutics, Icahn School of Medicine at Mount Sinai, New York, NY 10029, USA
| | - Abhijeet Kapoor
- Department of Structural and Chemical Biology, Icahn School of Medicine at Mount Sinai, New York, NY 10029, USA
| | - Paola Bisignano
- Department of Structural and Chemical Biology, Icahn School of Medicine at Mount Sinai, New York, NY 10029, USA
| | - Achla Gupta
- Department of Pharmacology and Systems Therapeutics, Icahn School of Medicine at Mount Sinai, New York, NY 10029, USA
| | - Mihaly Mezei
- Department of Structural and Chemical Biology, Icahn School of Medicine at Mount Sinai, New York, NY 10029, USA
| | - Sanjai Kumar
- Department of Chemistry and Biochemistry, Queens College, Flushing, NY 11367, USA
| | - Marta Filizola
- Department of Structural and Chemical Biology, Icahn School of Medicine at Mount Sinai, New York, NY 10029, USA
| | - Lakshmi A Devi
- Department of Pharmacology and Systems Therapeutics, Icahn School of Medicine at Mount Sinai, New York, NY 10029, USA.
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20
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Thiel G, Müller I, Rössler OG. Expression, signaling and function of Egr transcription factors in pancreatic β-cells and insulin-responsive tissues. Mol Cell Endocrinol 2014; 388:10-9. [PMID: 24631481 DOI: 10.1016/j.mce.2014.03.001] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 11/20/2013] [Revised: 02/26/2014] [Accepted: 03/03/2014] [Indexed: 12/15/2022]
Abstract
Egr-1 and the related zinc finger transcription factors Egr-2, Egr-3, and Egr-4 are stimulated by many extracellular signaling molecules and represent a convergence point for intracellular signaling cascades. Egr-1 expression is induced in insulinoma cells and pancreatic β-cells following stimulation with either glucose, or pregnenolone sulfate. Moreover, stimulation of Gαq and Gαs-coupled receptors enhances EGR-1 gene transcription. Functional studies revealed that Egr transcription factors control insulin biosynthesis via regulation of Pdx-1 expression. Glucose homeostasis and pancreatic islet size are regulated by Egr transcription factors, indicating that these proteins control central physiological parameters regulated by pancreatic β-cells. In addition, Egr-1 is an integral part of the insulin receptor signaling cascade in insulin-responsive tissues and influences insulin resistance.
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Affiliation(s)
- Gerald Thiel
- Department of Medical Biochemistry and Molecular Biology, University of Saarland Medical Center, D-66421 Homburg, Germany.
| | - Isabelle Müller
- Department of Medical Biochemistry and Molecular Biology, University of Saarland Medical Center, D-66421 Homburg, Germany
| | - Oliver G Rössler
- Department of Medical Biochemistry and Molecular Biology, University of Saarland Medical Center, D-66421 Homburg, Germany
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21
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M1 muscarinic receptor activation mediates cell death in M1-HEK293 cells. PLoS One 2013; 8:e72011. [PMID: 24023725 PMCID: PMC3759376 DOI: 10.1371/journal.pone.0072011] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/07/2012] [Accepted: 07/10/2013] [Indexed: 01/10/2023] Open
Abstract
HEK293 cells have been used extensively to generate stable cell lines to study G protein-coupled receptors, such as muscarinic acetylcholine receptors (mAChRs). The activation of M1 mAChRs in various cell types in vitro has been shown to be protective. To further investigate M1 mAChR-mediated cell survival, we generated stable HEK293 cell-lines expressing the human M1 mAChR. M1 mAChRs were efficiently expressed at the cell surface and efficiently internalised within 1 h by carbachol. Carbachol also induced early signalling cascades similar to previous reports. Thus, ectopically expressed M1 receptors behaved in a similar fashion to the native receptor over short time periods of analysis. However, substantial cell death was observed in HEK293-M1 cells within 24 h after carbachol application. Death was only observed in HEK cells expressing M1 receptors and fully blocked by M1 antagonists. M1 mAChR-stimulation mediated prolonged activation of the MEK-ERK pathway and resulted in prolonged induction of the transcription factor EGR-1 (>24 h). Blockade of ERK signalling with U0126 did not reduce M1 mAChR-mediated cell-death significantly but inhibited the acute induction of EGR-1. We investigated the time-course of cell death using time-lapse microscopy and xCELLigence technology. Both revealed the M1 mAChR cytotoxicity occurs within several hours of M1 activation. The xCELLigence assay also confirmed that the ERK pathway was not involved in cell-death. Interestingly, the MEK blocker did reduce carbachol-mediated cleaved caspase 3 expression in HEK293-M1 cells. The HEK293 cell line is a widely used pharmacological tool for studying G-protein coupled receptors, including mAChRs. Our results highlight the importance of investigating the longer term fate of these cells in short term signalling studies. Identifying how and why activation of the M1 mAChR signals apoptosis in these cells may lead to a better understanding of how mAChRs regulate cell-fate decisions.
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22
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Olango W, Géranton S, Roche M, Hunt S, Finn D. Novel molecular correlates of endocannabinoid-mediated fear-conditioned analgesia in rats. Eur J Pain 2013; 18:182-91. [DOI: 10.1002/j.1532-2149.2013.00369.x] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 06/20/2013] [Indexed: 11/12/2022]
Affiliation(s)
- W.M. Olango
- Pharmacology and Therapeutics; School of Medicine; National University of Ireland Galway; Ireland
- NCBES Neuroscience Cluster; National University of Ireland Galway; Ireland
- Centre for Pain Research; National University of Ireland Galway; Ireland
| | - S.M. Géranton
- Department of Cell and Developmental Biology; University College London; UK
| | - M. Roche
- Physiology; School of Medicine; National University of Ireland Galway; Ireland
- NCBES Neuroscience Cluster; National University of Ireland Galway; Ireland
- Centre for Pain Research; National University of Ireland Galway; Ireland
| | - S.P. Hunt
- Department of Cell and Developmental Biology; University College London; UK
| | - D.P. Finn
- Pharmacology and Therapeutics; School of Medicine; National University of Ireland Galway; Ireland
- NCBES Neuroscience Cluster; National University of Ireland Galway; Ireland
- Centre for Pain Research; National University of Ireland Galway; Ireland
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23
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Gyombolai P, Boros E, Hunyady L, Turu G. Differential β-arrestin2 requirements for constitutive and agonist-induced internalization of the CB1 cannabinoid receptor. Mol Cell Endocrinol 2013; 372:116-27. [PMID: 23541635 DOI: 10.1016/j.mce.2013.03.013] [Citation(s) in RCA: 34] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 10/04/2012] [Revised: 02/06/2013] [Accepted: 03/15/2013] [Indexed: 01/13/2023]
Abstract
CB1 cannabinoid receptor (CB1R) undergoes both constitutive and agonist-induced internalization, but the underlying mechanisms of these processes and the role of β-arrestins in the regulation of CB1R function are not completely understood. In this study, we followed CB1R internalization using confocal microscopy and bioluminescence resonance energy transfer measurements in HeLa and Neuro-2a cells. We found that upon activation CB1R binds β-arrestin2 (β-arr2), but not β-arrestin1. Furthermore, both the expression of dominant-negative β-arr2 (β-arr2-V54D) and siRNA-mediated knock-down of β-arr2 impaired the agonist-induced internalization of CB1R. In contrast, neither β-arr2-V54D nor β-arr2-specific siRNA had a significant effect on the constitutive internalization of CB1R. However, both constitutive and agonist-induced internalization of CB1R were impaired by siRNA-mediated depletion of clathrin heavy chain. We conclude that although clathrin is required for both constitutive and agonist-stimulated internalization of CB1R, β-arr2 binding is only required for agonist-induced internalization of the receptor suggesting that the molecular mechanisms underlying constitutive and agonist-induced internalization of CB1R are different.
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Affiliation(s)
- Pál Gyombolai
- Department of Physiology, Faculty of Medicine, Semmelweis University, Budapest, Hungary.
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24
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Laprairie RB, Kelly MEM, Denovan-Wright EM. Cannabinoids increase type 1 cannabinoid receptor expression in a cell culture model of striatal neurons: implications for Huntington's disease. Neuropharmacology 2013; 72:47-57. [PMID: 23602984 DOI: 10.1016/j.neuropharm.2013.04.006] [Citation(s) in RCA: 32] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/18/2013] [Revised: 03/14/2013] [Accepted: 04/02/2013] [Indexed: 10/27/2022]
Abstract
The type 1 cannabinoid receptor (CB1) is a G protein-coupled receptor that is expressed at high levels in the striatum. Activation of CB1 increases expression of neuronal trophic factors and inhibits neurotransmitter release from GABA-ergic striatal neurons. CB1 mRNA levels can be elevated by treatment with cannabinoids in non-neuronal cells. We wanted to determine whether cannabinoid treatment could induce CB1 expression in a cell culture model of striatal neurons and, if possible, determine the molecular mechanism by which this occurred. We found that treatment of STHdh(7/7) cells with the cannabinoids ACEA, mAEA, and AEA produced a CB1receptor-dependent increase in CB1 promoter activity, mRNA, and protein expression. This response was Akt- and NF-κB-dependent. Because decreased CB1 expression is thought to contribute to the pathogenesis of Huntington's disease (HD), we wanted to determine whether cannabinoids could increase CB1 expression in STHdh(7/111) and (111/111) cells expressing the mutant huntingtin protein. We observed that cannabinoid treatment increased CB1 mRNA levels approximately 10-fold in STHdh(7/111) and (111/111) cells, compared to vehicle treatment. Importantly, cannabinoid treatment improved ATP production, increased the expression of the trophic factor BDNF-2, and the mitochondrial regulator PGC1α, and reduced spontaneous GABA release, in HD cells. Therefore, cannabinoid-mediated increases in CB1 levels could reduce the severity of some molecular pathologies observed in HD.
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Affiliation(s)
- Robert B Laprairie
- Rm 6E Sir Charles Tupper Medical Bldg, Department of Pharmacology, Dalhousie University, 5850 College St., Halifax, NS, Canada B3H 4R2.
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25
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Horne EA, Coy J, Swinney K, Fung S, Cherry AET, Marrs WR, Naydenov AV, Lin YH, Sun X, Keene CD, Grouzmann E, Muchowski P, Bates GP, Mackie K, Stella N. Downregulation of cannabinoid receptor 1 from neuropeptide Y interneurons in the basal ganglia of patients with Huntington's disease and mouse models. Eur J Neurosci 2012; 37:429-40. [PMID: 23167744 DOI: 10.1111/ejn.12045] [Citation(s) in RCA: 37] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/10/2012] [Revised: 09/20/2012] [Accepted: 10/01/2012] [Indexed: 11/29/2022]
Abstract
Cannabinoid receptor 1 (CB(1) receptor) controls several neuronal functions, including neurotransmitter release, synaptic plasticity, gene expression and neuronal viability. Downregulation of CB(1) expression in the basal ganglia of patients with Huntington's disease (HD) and animal models represents one of the earliest molecular events induced by mutant huntingtin (mHtt). This early disruption of neuronal CB(1) signaling is thought to contribute to HD symptoms and neurodegeneration. Here we determined whether CB(1) downregulation measured in patients with HD and mouse models was ubiquitous or restricted to specific striatal neuronal subpopulations. Using unbiased semi-quantitative immunohistochemistry, we confirmed previous studies showing that CB(1) expression is downregulated in medium spiny neurons of the indirect pathway, and found that CB(1) is also downregulated in neuropeptide Y (NPY)/neuronal nitric oxide synthase (nNOS)-expressing interneurons while remaining unchanged in parvalbumin- and calretinin-expressing interneurons. CB(1) downregulation in striatal NPY/nNOS-expressing interneurons occurs in R6/2 mice, Hdh(Q150/Q150) mice and the caudate nucleus of patients with HD. In R6/2 mice, CB(1) downregulation in NPY/nNOS-expressing interneurons correlates with diffuse expression of mHtt in the soma. This downregulation also occludes the ability of cannabinoid agonists to activate the pro-survival signaling molecule cAMP response element-binding protein in NPY/nNOS-expressing interneurons. Loss of CB(1) signaling in NPY/nNOS-expressing interneurons could contribute to the impairment of basal ganglia functions linked to HD.
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Affiliation(s)
- Eric A Horne
- Department of Pharmacology, University of Washington, 1959 N.E. Pacific St., Seattle, WA 98195-7280, USA
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Nicoll G, Davidson S, Shanley L, Hing B, Lear M, McGuffin P, Ross R, MacKenzie A. Allele-specific differences in activity of a novel cannabinoid receptor 1 (CNR1) gene intronic enhancer in hypothalamus, dorsal root ganglia, and hippocampus. J Biol Chem 2012; 287:12828-34. [PMID: 22362764 PMCID: PMC3339935 DOI: 10.1074/jbc.m111.336750] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/23/2011] [Revised: 02/09/2012] [Indexed: 12/30/2022] Open
Abstract
Polymorphisms within intron 2 of the CNR1 gene, which encodes cannabinoid receptor 1 (CB(1)), have been associated with addiction, obesity, and brain volume deficits. We used comparative genomics to identify a polymorphic (rs9444584-C/T) sequence (ECR1) in intron 2 of the CNR1 gene that had been conserved for 310 million years. The C-allele of ECR1 (ECR1(C)) acted as an enhancer in hypothalamic and dorsal root ganglia cells and responded to MAPK activation through the MEKK pathway but not in hippocampal cells. However, ECR1(T) was significantly more active in hypothalamic and dorsal root ganglia cells but, significantly, and in contrast to ECR1(C), was highly active in hippocampal cells where it also responded strongly to activation of MAPK. Intriguingly, rs9444584 is in strong linkage disequilibrium with two other SNPs (rs9450898 (r(2) = 0.841) and rs2023239 (r(2) = 0.920)) that have been associated with addiction, obesity (rs2023239), and reduced fronto-temporal white matter volumes in schizophrenia patients as a result of cannabis misuse (rs9450898). Considering their high linkage disequilibrium and the increased response of ECR1(T) to MAPK signaling when compared with ECR1(C), it is possible that the functional effects of the different alleles of rs9444584 may play a role in the conditions associated with rs9450898 and rs2023239. Further analysis of the different alleles of ECR1 may lead to a greater understanding of the role of CNR1 gene misregulation in these conditions as well as chronic inflammatory pain.
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Affiliation(s)
- Gemma Nicoll
- From the School of Medical Sciences, Institute of Medical Sciences, Foresterhill, University of Aberdeen, Aberdeen AB25 2ZD, Scotland and
| | - Scott Davidson
- From the School of Medical Sciences, Institute of Medical Sciences, Foresterhill, University of Aberdeen, Aberdeen AB25 2ZD, Scotland and
| | - Lynne Shanley
- From the School of Medical Sciences, Institute of Medical Sciences, Foresterhill, University of Aberdeen, Aberdeen AB25 2ZD, Scotland and
| | - Ben Hing
- From the School of Medical Sciences, Institute of Medical Sciences, Foresterhill, University of Aberdeen, Aberdeen AB25 2ZD, Scotland and
| | - Marissa Lear
- From the School of Medical Sciences, Institute of Medical Sciences, Foresterhill, University of Aberdeen, Aberdeen AB25 2ZD, Scotland and
| | - Peter McGuffin
- the Medical Research Council Social, Genetic and Developmental Psychiatry Centre Centre, Institute of Psychiatry, King's College London, DeCrespigny Park, London SE5 8AF3, United Kingdom
| | - Ruth Ross
- From the School of Medical Sciences, Institute of Medical Sciences, Foresterhill, University of Aberdeen, Aberdeen AB25 2ZD, Scotland and
| | - Alasdair MacKenzie
- From the School of Medical Sciences, Institute of Medical Sciences, Foresterhill, University of Aberdeen, Aberdeen AB25 2ZD, Scotland and
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Kleyer J, Nicolussi S, Taylor P, Simonelli D, Furger E, Anderle P, Gertsch J. Cannabinoid receptor trafficking in peripheral cells is dynamically regulated by a binary biochemical switch. Biochem Pharmacol 2012; 83:1393-412. [PMID: 22387618 DOI: 10.1016/j.bcp.2012.02.014] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/18/2012] [Revised: 02/16/2012] [Accepted: 02/17/2012] [Indexed: 12/20/2022]
Abstract
The cannabinoid G protein-coupled receptors (GPCRs) CB₁ and CB₂ are expressed in different peripheral cells. Localization of GPCRs in the cell membrane determines signaling via G protein pathways. Here we show that unlike in transfected cells, CB receptors in cell lines and primary human cells are not internalized upon agonist interaction, but move between cytoplasm and cell membranes by ligand-independent trafficking mechanisms. Even though CB receptors are expressed in many cells of peripheral origin they are not always localized in the cell membrane and in most cancer cell lines the ratios between CB₁ and CB₂ receptor gene and surface expression vary significantly. In contrast, CB receptor cell surface expression in HL60 cells is subject to significant oscillations and CB₂ receptors form oligomers and heterodimers with CB₁ receptors, showing synchronized surface expression, localization and trafficking. We show that hydrogen peroxide and other nonspecific protein tyrosine phosphatase inhibitors (TPIs) such as phenylarsine oxide trigger both CB₂ receptor internalization and externalization, depending on receptor localization. Phorbol ester-mediated internalization of CB receptors can be inhibited via this switch. In primary human immune cells hydrogen peroxide and other TPIs lead to a robust internalization of CB receptors in monocytes and an externalization in T cells. This study describes, for the first time, the dynamic nature of CB receptor trafficking in the context of a biochemical switch, which may have implications for studies on the cell-type specific effects of cannabinoids and our understanding of the regulation of CB receptor cell surface expression.
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Affiliation(s)
- Jonas Kleyer
- Institute of Biochemistry and Molecular Medicine, Swiss National Centre of Competence in Research NCCR TransCure, University of Bern, Bühlstrasse 28, CH-3012 Bern, Switzerland
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Grimsey NL, Moodley KS, Glass M, Graham ES. Sensitive and accurate quantification of human leukocyte migration using high-content Discovery-1 imaging system and ATPlite assay. ACTA ACUST UNITED AC 2011; 17:386-93. [PMID: 22140120 DOI: 10.1177/1087057111428985] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/04/2023]
Abstract
Migration is a fundamental aspect of leukocyte behavior and represents a significant therapeutic target clinically. However, most migration assays used in research are relatively low throughput and not easily compatible with rapid analysis or high-throughput screening (HTS) protocols required for drug screening assays. We therefore investigated the quantification of the migration of human leukocytes using the Molecular Devices high-content Discovery-1 platform or PerkinElmer ATPlite assay compared to manual counting. We have conducted extensive assay validation, investigating the detection limits, sensitivity, and precision of each method to count human leukocytes. Leukocyte migration assays were conducted using 96-well HTS-Transwell plates and the potent chemokine stromal cell-derived factor-1 (SDF-1). We reveal that the Discovery-1 and ATPlite methods developed here provide useful approaches to quantify leukocyte migration in an HTS manner with high levels of detection, sensitivity, and precision.
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Affiliation(s)
- Natasha L Grimsey
- Centre for Brain Research and Department of Pharmacology and Clinical Pharmacology, School of Medical Sciences, Faculty of Medical and Health Sciences, University of Auckland, Auckland, New Zealand
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Wasik AM, Christensson B, Sander B. The role of cannabinoid receptors and the endocannabinoid system in mantle cell lymphoma and other non-Hodgkin lymphomas. Semin Cancer Biol 2011; 21:313-21. [PMID: 22024769 DOI: 10.1016/j.semcancer.2011.10.004] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/08/2023]
Abstract
The initiating oncogenic event in mantle cell lymphoma (MCL) is the translocation of cyclin D1, t(11;14)(q13;q32). However, other genetic aberrations are necessary for an overt lymphoma to arise. Like other B cell lymphomas, MCL at some points during the oncogenesis is dependent on interactions with other cells and factors in the microenvironment. The G protein coupled receptors cannabinoid receptors 1 and 2 (CB1 and CB2) are expressed at low levels on non-malignant lymphocytes and at higher levels in MCL and other lymphoma subtypes. In this review we give an overview of what is known on the role of the cannabinoid receptors and their ligands in lymphoma as compared to non-malignant T and B lymphocytes. In MCL cannabinoids mainly reduce cell proliferation and induce cell death. Importantly, our recent findings demonstrate that cannabinoids may induce either apoptosis or another type of programmed cell death, cytoplasmic vacuolation/paraptosis in MCL. The signalling to death has been partly characterized. Even though cannabinoid receptors seem to be expressed in many other types of B cell lymphoma, the functional role of cannabinoid receptor targeting is yet largely unknown. In non-malignant B and T lymphocytes, cannabinoid receptors are up-regulated in response to antigen receptor signalling or CD40. For T lymphocytes IL-4 has also a crucial role in transcriptional regulation of CB1. In lymphocytes, cannabinoid act in several ways - by affecting cell migration, cytokine response, at high doses inhibit cell proliferation and inducing cell death. The possible role for the endocannabinoid system in the immune microenvironment of lymphoma is discussed.
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Affiliation(s)
- Agata M Wasik
- Division of Pathology, Department of Laboratory Medicine, Karolinska Institutet and Karolinska University Hospital Huddinge, SE 141 86 Stockholm, Sweden.
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Real-time profiling of NK cell killing of human astrocytes using xCELLigence technology. J Neurosci Methods 2011; 200:173-80. [PMID: 21781988 DOI: 10.1016/j.jneumeth.2011.07.005] [Citation(s) in RCA: 43] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/03/2011] [Revised: 07/05/2011] [Accepted: 07/07/2011] [Indexed: 12/21/2022]
Abstract
We have conducted the first profiling of human Natural Killer (NK) cell mediated killing of astrocytes using xCELLigence technology. The sensitivity and applicability of xCELLigence was compared to lactate dehydrogenase (LDH) release and time-lapsed microscopy to validate the killing events. The xCELLigence technology uses electrical impedance measurements from adherent cells and converts into Cell Index (CI). NK cells did not register any Cell Index signal directly, therefore all changes in Cell Index are a direct measure of astrocyte responses. Astrocytes are insensitive to basal NK cells (non-activated NKs). Whereas NK cells activated by IL-2 prior to culture with targets rapidly kill astrocytes. This observation was supported by all methods of analysis. Using the xCELLigence we were able to monitor the longer term killing profile. This demonstrated that at all NK ratios, death was achieved if given long enough. In addition, the development of the killing phenotype was investigated by inducing lymphokine activated killing with IL-2 in the presence of the target astrocytes. In this paradigm of killing, the xCELLigence was the only assay suitable due to the prolonged time-course required for killing, which required 4-5 days to achieve maximal killing (100%). This suggested that the astrocytes can directly suppress the killing activity of the NK cells. These data highlight the sensitivity, applicability and profiling power of the xCELLigence system and support its use for further investigation of NK-killing of healthy and/or tumourogenic astrocytic cells.
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Koshimizu H, Cawley NX, Kim T, Yergey AL, Loh YP. Serpinin: a novel chromogranin A-derived, secreted peptide up-regulates protease nexin-1 expression and granule biogenesis in endocrine cells. Mol Endocrinol 2011; 25:732-44. [PMID: 21436258 DOI: 10.1210/me.2010-0124] [Citation(s) in RCA: 40] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/19/2022] Open
Abstract
Previously we demonstrated that chromogranin A (CgA) promoted secretory granule biogenesis in endocrine cells by stabilizing and preventing granule protein degradation in the Golgi, through up-regulation of expression of the protease inhibitor, protease nexin-1 (PN-1). However, the mechanism by which CgA signals the increase of PN-1 expression is unknown. Here we identified a 2.9-kDa CgA-C-terminus peptide, which we named serpinin, in conditioned media from AtT-20 cells, a corticotroph cell line, which up-regulated PN-1 mRNA expression. Serpinin was secreted from AtT-20 cells upon high potassium stimulation and increased PN-1 mRNA transcription in these cells, in an actinomycin D-inhibitable manner. CgA itself and other CgA-derived peptides, when added to AtT-20 cell media, had no effect on PN-1 expression. Treatment of AtT-20 cells with 10 nm serpinin elevated cAMP levels and PN-1 mRNA expression, and this effect was inhibited by a protein kinase A inhibitor, 6-22 amide. Serpinin and a cAMP analog, 8-bromo-cAMP, promoted the translocation of the transcription factor Sp1 into the nucleus, which is known to drive PN-1 expression. Additionally, an Sp1 inhibitor, mithramycin A inhibited the serpinin-induced PN-1 mRNA up-regulation. Furthermore, a luciferase reporter assay demonstrated serpinin-induced up-regulation of PN-1 promoter activity in an Sp1-dependent manner. When added to CgB-transfected 6T3 cells, a mutant AtT20 cell line, serpinin induced granule biogenesis as evidenced by the presence of CgB puncta accumulation in the processes and tips. Our findings taken together show that serpinin, a novel CgA-derived peptide, is secreted upon stimulation of corticotrophs and plays an important autocrine role in up-regulating PN-1-dependent granule biogenesis via a cAMP-protein kinase A-Sp1 pathway to replenish released granules.
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Affiliation(s)
- Hisatsugu Koshimizu
- Section on Cellular Neurobiology, Eunice Kennedy Shriver National Institute of Child Health and Human Development, National Institutes of Health, Bethesda, Maryland 20892, USA
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Phospholipase C-η1 is activated by intracellular Ca(2+) mobilization and enhances GPCRs/PLC/Ca(2+) signaling. Cell Signal 2011; 23:1022-9. [PMID: 21262355 DOI: 10.1016/j.cellsig.2011.01.017] [Citation(s) in RCA: 36] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/22/2010] [Accepted: 01/14/2011] [Indexed: 11/20/2022]
Abstract
Phospholipase C-η1 (PLC-η1) is the most recently identified PLC isotype and is primarily expressed in nerve tissue. However, its functional role is unclear. In the present study, we report for the first time that PLC-η1 acts as a signal amplifier in G protein-coupled receptor (GPCR)-mediated PLC and Ca(2+) signaling. Short-hairpin RNA (shRNA)-mediated knockdown of endogenous PLC-η1 reduced lysophosphatidic acid (LPA)-, bradykinin (BK)-, and PACAP-induced PLC activity in mouse neuroblastoma Neuro2A (N2A) cells, indicating that PLC-η1 participates in GPCR-mediated PLC activation. Interestingly, ionomycin-induced PLC activity was significantly decreased by PLC-η1, but not PLC-η2, knockdown. In addition, we found that intracellular Ca(2+) source is enough for PLC-η1 activation. Furthermore, the IP(3) receptor inhibitor, 2-APB, inhibited LPA-induced PLC activity in control N2A cells, whereas this effect was not observed in PLC-η1 knockdown N2A cells, suggesting a pivotal role of intracellular Ca(2+) mobilization in PLC-η1 activation. Finally, we found that LPA-induced ERK1/2 phosphorylation and expression of the downstream target gene, krox-24, were significantly decreased by PLC-η1 knockdown, and these knockdown effects were abolished by 2-APB. Taken together, our results strongly suggest that PLC-η1 is activated via intracellular Ca(2+) mobilization from the ER, and therefore amplifies GPCR-mediated signaling.
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Benz AH, Shajari M, Peruzki N, Dehghani F, Maronde E. Early growth response-1 induction by fibroblast growth factor-1 via increase of mitogen-activated protein kinase and inhibition of protein kinase B in hippocampal neurons. Br J Pharmacol 2010; 160:1621-30. [PMID: 20649566 DOI: 10.1111/j.1476-5381.2010.00812.x] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022] Open
Abstract
BACKGROUND AND PURPOSE The transcription factor early growth response-1 (Egr-1) and the acidic fibroblast growth factor (FGF-1) are involved in many regulatory processes, including hippocampus-associated learning and memory. However, the intracellular signalling mechanisms regulating Egr-1 in hippocampal cells are not entirely understood. EXPERIMENTAL APPROACH We used primary mouse hippocampal neurons and the mouse hippocampal neuronal cell line HT22 to investigate how FGF-1 transiently induces Egr-1 protein. This was accomplished by a range of techniques including Western blotting, immunofluorescence, specific protein kinase inhibitors and transfectable constitutively active protein kinase constructs. KEY RESULTS Protein kinase B (PKB) and mitogen-activated protein kinase (MAPK) were both initially phosphorylated and activated by FGF-1 treatment, but when phosphorylated MAPK reached maximal activation, phosphorylated PKB was at its lowest levels, suggesting an interaction between MAPK kinase (MEK-1/2) and phosphatidyl inositol-3-kinase (PI3K) during Egr-1 induction. Interestingly, pharmacological inhibition of MEK-1/2 resulted in a robust increase in the phosphorylation of PKB, which was repressed in the presence of increasing doses of a PI3K inhibitor. FGF-1-mediated Egr-1 induction was impaired by inhibition of MEK-1/2, but not of PI3K. However, elevated levels of PKB, induced by transfection of constitutively active PKB (myrAkt) into hippocampal neuronal HT22 cells, led to reduced levels of Egr-1 after FGF-1 application. CONCLUSIONS AND IMPLICATIONS Our data indicate a contribution of inactive (dephosphorylated) PKB to FGF-1-mediated induction of Egr-1, and strongly suggest a functionally and pharmacologically interesting cross-talk between MEK-1/2 and PI3K signalling in hippocampal neurons after FGF-1 stimulation that may play a role in hippocampal synaptic plasticity.
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Affiliation(s)
- Alexander H Benz
- Institut für Anatomie III, Dr Senckenbergische Anatomie, Goethe-Universität, Frankfurt am Main, Germany
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Scotter EL, Goodfellow CE, Graham ES, Dragunow M, Glass M. Neuroprotective potential of CB1 receptor agonists in an in vitro model of Huntington's disease. Br J Pharmacol 2010; 160:747-61. [PMID: 20590577 DOI: 10.1111/j.1476-5381.2010.00773.x] [Citation(s) in RCA: 53] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/06/2023] Open
Abstract
BACKGROUND AND PURPOSE The therapeutic potential of cannabinoids in Huntington's disease (HD) has been investigated by several groups with complex and sometimes contrasting results. We sought to examine key points of intersection between cannabinoid receptor 1 (CB(1)) signalling, survival and the formation of mutant huntingtin aggregates in HD. EXPERIMENTAL APPROACH Using a simplified pheochromocytoma (PC12) cell model of HD expressing exon 1 of wild-type or mutant huntingtin, we assayed cell death and aggregate formation using high-throughput cytotoxicity and image-based assays respectively. KEY RESULTS CB(1) activation by HU210 conferred a small but significant level of protection against mutant huntingtin-induced cell death. Pertussis toxin uncoupled HU210 from the inhibition of cAMP, preventing rescue of cell death. Phosphorylation of extracellular signal-regulated kinase (ERK) was also critical to CB(1)-mediated rescue. Conversely, treatments that elevated cAMP exacerbated mutant huntingtin-induced cell death. Despite opposing effects on HD cell survival, both HU210 and compounds that elevated cAMP increased the formation of mutant huntingtin aggregates. The increase in aggregation by HU210 was insensitive to Pertussis toxin and UO126, suggesting a G-protein alpha subtype s (G(s))-linked mechanism. CONCLUSIONS AND IMPLICATIONS We suggest that the CB(1) receptor, through G-protein alpha subtype i/o (G(i/o))-linked, ERK-dependent signal transduction, is a therapeutic target in HD. However the protective potential of CB(1) may be limited by promiscuous coupling to G(s), the stimulation of cAMP formation and increased aggregate formation. This may underpin the poor therapeutic efficacy of cannabinoids in more complex model systems and suggest that therapies that are selective for the G(i/o), ERK pathway may be of most benefit in HD.
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Affiliation(s)
- E L Scotter
- Department of Pharmacology and Clinical Pharmacology, Faculty of Medical and Health Sciences, University of Auckland, Grafton, Auckland, New Zealand
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Grimsey NL, Graham ES, Dragunow M, Glass M. Cannabinoid Receptor 1 trafficking and the role of the intracellular pool: implications for therapeutics. Biochem Pharmacol 2010; 80:1050-62. [PMID: 20599795 DOI: 10.1016/j.bcp.2010.06.007] [Citation(s) in RCA: 48] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/01/2010] [Revised: 06/08/2010] [Accepted: 06/14/2010] [Indexed: 11/26/2022]
Abstract
Cannabinoid Receptor 1 (CB(1)), an abundant G-protein coupled receptor in the CNS, is currently of significant interest as a therapeutic target. Although the cellular control of receptor trafficking is intimately linked with drug effects, CB(1) trafficking is poorly defined in the current literature and conflicting evidence exists as to whether CB(1) should be classified as a recycling, degrading or "dual-fate" receptor. Of particular interest is the widely noted intracellular pool which has been speculated to form part of a constitutive internalization and recycling pathway. This study performs a detailed quantification of CB(1) trafficking in four cell lines, one of which expresses CB(1) endogenously. We demonstrate that, contrary to previous reports, CB(1) does not recycle following constitutive or agonist-induced internalization but instead exhibits a primarily degradative phenotype. Further, our data suggest that the intracellular pool does not contribute to cell surface re-population. These findings have significant implications for the interpretation of CB(1) biochemical studies and the design and application of cannabinoid therapeutics.
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Affiliation(s)
- Natasha L Grimsey
- Centre for Brain Research, Faculty of Medical and Health Sciences, University of Auckland, Private Bag 92019, Auckland, New Zealand.
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36
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Greenwood JM, Dragunow M. M3 muscarinic receptors promote cell survival through activation of the extracellular regulated kinase (ERK1/2) pathway. Eur J Pharmacol 2010; 640:38-45. [PMID: 20519144 DOI: 10.1016/j.ejphar.2010.05.013] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/15/2009] [Revised: 04/15/2010] [Accepted: 05/06/2010] [Indexed: 10/19/2022]
Abstract
Activation of certain subtypes of the muscarinic acetylcholine receptor can enhance cell survival. In SK-N-SH human neuroblastoma cells, muscarinic acetylcholine receptor activation induces phosphorylation of CREB and induction of EGR1, transcription factors associated with cell growth and survival. We identified the M3 muscarinic acetylcholine receptor subtype as being primarily responsible for these transcription factor responses after stimulation with carbachol, using subtype-preferring receptor antagonists and muscarinic snake toxins. In a cell survival/death model in SK-N-SH cells deprived of serum growth factors, carbachol increased cell viability, an effect blocked by the non-specific muscarinic antagonist atropine and the M3-preferring antagonist 4-diphenylacetoxy-N-methylpiperidine methiodide (4-DAMP), suggesting that the M3 receptor is also driving the survival response in these cells. This cytoprotection is largely dependent on activation of the p44/42 extracellular regulated kinase (ERK1/2) pathway. Understanding such survival signalling pathways is important for both potential interventions in neurodegenerative disease and for targeting neuroblastoma and malignancies of the central nervous system.
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Affiliation(s)
- Jeffrey M Greenwood
- Department of Pharmacology and Clinical Pharmacology, Faculty of Medical and Health Sciences, University of Auckland, Private Bag 92019, Auckland, New Zealand.
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Influence of natriuretic peptide receptor-1 on survival and cardiac hypertrophy during development. Biochim Biophys Acta Mol Basis Dis 2009; 1792:1175-84. [PMID: 19782130 DOI: 10.1016/j.bbadis.2009.09.009] [Citation(s) in RCA: 29] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/16/2009] [Revised: 08/27/2009] [Accepted: 09/17/2009] [Indexed: 11/21/2022]
Abstract
The heart adapts to an increased workload through the activation of a hypertrophic response within the cardiac ventricles. This response is characterized by both an increase in the size of the individual cardiomyocytes and an induction of a panel of genes normally expressed in the embryonic and neonatal ventricle, such as atrial natriuretic peptide (ANP). ANP and brain natriuretic peptide (BNP) exert their biological actions through activation of the natriuretic peptide receptor-1 (Npr1). The current study examined mice lacking Npr1 (Npr1(-/-)) activity and investigated the effects of the absence of Npr1 signaling during cardiac development on embryo viability, cardiac structure and gene and protein expression. Npr1(-/-)embryos were collected at embryonic day (ED) 12.5, 15.5 and neonatal day 1 (ND 1). Npr1(-/-)embryos occurred at the expected Mendelian frequency at ED 12.5, but knockout numbers were significantly decreased at ED 15.5 and ND 1. There was no indication of cardiac structural abnormalities in surviving embryos. However, Npr1(-/-)embryos exhibited cardiac enlargement (without fibrosis) from ED 15.5 as well as significantly increased ANP mRNA and protein expression compared to wild-type (WT) mice, but no concomitant increase in expression of the hypertrophy-related transcription factors, Mef2A, Mef2C, GATA-4, GATA-6 or serum response factor (SRF). However, there was a significant decrease in Connexin-43 (Cx43) gene and protein expression at mid-gestation in Npr1(-/-)embryos. Our findings suggest that the mechanism by which natriuretic peptide signaling influences cardiac development in Npr1(-/-) mice is distinct from that seen during the development of pathological cardiac hypertrophy and fibrosis. The decreased viability of Npr1(-/-)embryos may result from a combination of cardiomegaly and dysregulated Cx43 protein affecting cardiac contractility.
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Zhang F, Challapalli SC, Smith PJW. Cannabinoid CB(1) receptor activation stimulates neurite outgrowth and inhibits capsaicin-induced Ca(2+) influx in an in vitro model of diabetic neuropathy. Neuropharmacology 2009; 57:88-96. [PMID: 19501110 DOI: 10.1016/j.neuropharm.2009.04.017] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/29/2008] [Revised: 04/21/2009] [Accepted: 04/21/2009] [Indexed: 12/26/2022]
Abstract
Cannabinoid CB(1) receptors mediate, in part, the neuroprotectant properties of endocannabinoids, and altered signalling via the CB(1) receptor may contribute to the pathogenesis of diabetic neuropathy. We investigated CB(1) receptor function in PC12 cells differentiated into a neuronal phenotype with nerve growth factor (NGF, 50 ng/ml) in 5.5 and 50 mM concentrations of glucose. High glucose was associated with impaired NGF-induced neurite outgrowth (P < 0.01; n = 185-218) and reduced expression of CB(1) receptor mRNA (P < 0.01; n = 6) on day 6 of culture. Whilst treatment of hyperglycemic cells with HU210 (0.03-3 microM) increased neurite length in a concentration-dependent manner (P < 0.01; n = 136-218), CB(1) receptor expression was not significantly altered by chronic agonist stimulation (P = 0.32; n = 6 per group). Application of the CB(1) agonist HU210 (1 microM) inhibited capsaicin-induced calcium transients to a similar degree in cells cultured in high glucose (40%) versus normal (43%) (P < 0.05; n = 33-50). HU210-mediated rescue of neurite outgrowth and inhibition of calcium influx was blocked by the selective CB(1) antagonist AM251 (1 microM), but not by the selective CB(2) antagonist AM630 (1 microM), confirming the role of CB(1) receptors. High glucose treatment did not significantly elevate endocannabinoid levels. These results suggest that high glucose concentrations are associated with decreased expression, but preserved function of CB(1) receptors in nerve cells.
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Affiliation(s)
- Fan Zhang
- School of Life Sciences, Edinburgh Napier University, Scotland, UK
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Abstract
High-content analysis (HCA) combines automated microscopy and automated image analysis to quantify complex cellular anatomy and biochemistry objectively, accurately and quickly. High-content assays that are applicable to neuroscience include those that can quantify various aspects of dendritic trees, protein aggregation, transcription factor translocation, neurotransmitter receptor internalization, neuron and synapse number, cell migration, proliferation and apoptosis. The data that are generated by HCA are rich and multiplexed. HCA thus provides a powerful high-throughput tool for neuroscientists.
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Blázquez C, Salazar M, Carracedo A, Lorente M, Egia A, González-Feria L, Haro A, Velasco G, Guzmán M. Cannabinoids Inhibit Glioma Cell Invasion by Down-regulating Matrix Metalloproteinase-2 Expression. Cancer Res 2008; 68:1945-52. [DOI: 10.1158/0008-5472.can-07-5176] [Citation(s) in RCA: 122] [Impact Index Per Article: 7.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
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Grimsey NL, Goodfellow CE, Scotter EL, Dowie MJ, Glass M, Graham ES. Specific detection of CB1 receptors; cannabinoid CB1 receptor antibodies are not all created equal! J Neurosci Methods 2008; 171:78-86. [PMID: 18406468 DOI: 10.1016/j.jneumeth.2008.02.014] [Citation(s) in RCA: 98] [Impact Index Per Article: 6.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/19/2007] [Revised: 02/12/2008] [Accepted: 02/14/2008] [Indexed: 11/19/2022]
Abstract
The study of endogenous cannabinoid CB1 receptor proteins in neuronal tissues and cells relies on the availability of highly specific antibodies. We have tested the ability of a series of CB1 antibodies to detect endogenous receptors in brain as well as hemagglutinin (HA)-tagged receptors transfected into HEK-293 cells using a combination of immunological methods. An initial comparison of several CB1 antibodies in mouse brain revealed substantial differences in staining pattern to ligand binding by autoradiography. Antibodies were then tested immunocytochemically against HEK cells expressing HA-tagged rat and human CB1 receptors. None of the commercial antibodies tested were able to detect the receptor in this context. All antibodies were then screened by Western blotting using lysates from the HEK cells and rodent brain homogenates. Again, none of the commercially available antibodies detected proteins of the correct molecular weight in transfected cell lines or brain homogenates, although all recognized multiple proteins in brain tissues. We conclude that the commercially available antibodies we tested failed to detect CB1 receptors abundantly expressed in HEK cells or native receptors in brain slices or homogenates. As such, comprehensive validation of the specificity of these CB1 antibodies for a particular application is essential before use.
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Affiliation(s)
- Natasha L Grimsey
- Department of Pharmacology and Clinical Pharmacology, University of Auckland, Private Bag 92019, Auckland, New Zealand
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Alexander SPH, Kendall DA. The complications of promiscuity: endocannabinoid action and metabolism. Br J Pharmacol 2007; 152:602-23. [PMID: 17876303 PMCID: PMC2190010 DOI: 10.1038/sj.bjp.0707456] [Citation(s) in RCA: 102] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/18/2007] [Revised: 08/15/2007] [Accepted: 08/16/2007] [Indexed: 01/27/2023] Open
Abstract
In this review, we present our understanding of the action and metabolism of endocannabinoids and related endogenous molecules. It is clear that the interactions between the multiple endocannabinoid-like molecules (ECLs) are highly complex, both at the level of signal transduction and metabolism. Thus, ECLs are a group of ligands active at 7-transmembrane and nuclear receptors, as well as transmitter-gated and ion channels. ECLs and their metabolites can converge on common endpoints (either metabolic or signalling) through contradictory or reinforcing pathways. We highlight the complexity of the endocannabinoid system, based on the promiscuous nature of ECLs and their metabolites, as well as the synthetic modulators of the endocannabinoid system.
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Affiliation(s)
- S P H Alexander
- School of Biomedical Sciences and Institute of Neuroscience, University of Nottingham Medical School, Nottingham NG7 7LP, UK.
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Basavarajappa BS. Neuropharmacology of the endocannabinoid signaling system-molecular mechanisms, biological actions and synaptic plasticity. Curr Neuropharmacol 2007; 5:81-97. [PMID: 18084639 PMCID: PMC2139910 DOI: 10.2174/157015907780866910] [Citation(s) in RCA: 79] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/07/2006] [Revised: 02/07/2007] [Accepted: 02/14/2007] [Indexed: 11/22/2022] Open
Abstract
The endocannabinoid signaling system is composed of the cannabinoid receptors; their endogenous ligands, the endocannabinoids; the enzymes that produce and inactivate the endocannabinoids; and the endocannabinoid transporters. The endocannabinoids are a new family of lipidic signal mediators, which includes amides, esters, and ethers of long-chain polyunsaturated fatty acids. Endocannabinoids signal through the same cell surface receptors that are targeted by Delta(9)-tetrahydrocannabinol (Delta(9)THC), the active principles of cannabis sativa preparations like hashish and marijuana. The biosynthetic pathways for the synthesis and release of endocannabinoids are still rather uncertain. Unlike neurotransmitter molecules that are typically held in vesicles before synaptic release, endocannabinoids are synthesized on demand within the plasma membrane. Once released, they travel in a retrograde direction and transiently suppress presynaptic neurotransmitter release through activation of cannabinoid receptors. The endocannabinoid signaling system is being found to be involved in an increasing number of pathological conditions. In the brain, endocannabinoid signaling is mostly inhibitory and suggests a role for cannabinoids as therapeutic agents in central nervous system (CNS) disease. Their ability to modulate synaptic efficacy has a wide range of functional consequences and provides unique therapeutic possibilities. The present review is focused on new information regarding the endocannabinoid signaling system in the brain. First, the structure, anatomical distribution, and signal transduction mechanisms of cannabinoid receptors are described. Second, the synthetic pathways of endocannabinoids are discussed, along with the putative mechanisms of their release, uptake, and degradation. Finally, the role of the endocannabinoid signaling system in the CNS and its potential as a therapeutic target in various CNS disease conditions, including alcoholism, are discussed.
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Affiliation(s)
- Balapal S Basavarajappa
- Division of Analytical Psychopharmacology, New York State Psychiatric Institute, New York, NY 10032, USA.
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Wenzel K, Daskalow K, Herse F, Seitz S, Zacharias U, Schenk JA, Schulz H, Hubner N, Micheel B, Schlag PM, Osterziel KJ, Ozcelik C, Scherneck S, Jandrig B. Expression of the protein phosphatase 1 inhibitor KEPI is downregulated in breast cancer cell lines and tissues and involved in the regulation of the tumor suppressor EGR1 via the MEK-ERK pathway. Biol Chem 2007; 388:489-95. [PMID: 17516844 DOI: 10.1515/bc.2007.062] [Citation(s) in RCA: 13] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/15/2022]
Abstract
KEPI is a protein kinase C-potentiated inhibitory protein for type 1 Ser/Thr protein phosphatases. We found no or reduced expression of KEPI in breast cancer cell lines, breast tumors and metastases in comparison to normal breast cell lines and tissues, respectively. KEPI protein expression and ubiquitous localization was detected with a newly generated antibody. Ectopic KEPI expression in MCF7 breast cancer cells induced differential expression of 95 genes, including the up-regulation of the tumor suppressors EGR1 (early growth response 1) and PTEN (phosphatase and tensin homolog), which is regulated by EGR1. We further show that the up-regulation of EGR1 in MCF7/KEPI cells is mediated by MEK-ERK signaling. The inhibition of this pathway by the MEK inhibitor UO126 led to a strong decrease in EGR1 expression in MCF7/KEPI cells. These results reveal a novel role for KEPI in the regulation of the tumor suppressor gene EGR1 via activation of the MEK-ERK MAPK pathway.
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Affiliation(s)
- Katrin Wenzel
- Max Delbrück Center for Molecular Medicine, Robert-Rössle-Strasse 10, Berlin, Germany.
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