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Comyn T, Preat T, Pavlowsky A, Plaçais PY. PKCδ is an activator of neuronal mitochondrial metabolism that mediates the spacing effect on memory consolidation. BIORXIV : THE PREPRINT SERVER FOR BIOLOGY 2024:2023.10.06.561186. [PMID: 38948698 PMCID: PMC11212906 DOI: 10.1101/2023.10.06.561186] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 07/02/2024]
Abstract
Relevance-based selectivity and high energy cost are two distinct features of long-term memory (LTM) formation that warrant its default inhibition. Spaced repetition of learning is a highly conserved cognitive mechanism that can lift this inhibition. Here, we questioned how the spacing effect integrates experience selection and energy efficiency at the cellular and molecular levels. We showed in Drosophila that spaced training triggers LTM formation by extending over several hours an increased mitochondrial metabolic activity in neurons of the associative memory center, the mushroom bodies (MBs). We found that this effect is mediated by PKCδ, a member of the so-called 'novel PKC' family of enzymes, which uncovers the critical function of PKCδ in neurons as a regulator of mitochondrial metabolism for LTM. Additionally, PKCδ activation and translocation to mitochondria result from LTM-specific dopamine signaling on MB neurons. By bridging experience-dependent neuronal circuit activity with metabolic modulation of memory-encoding neurons, PKCδ signaling binds the cognitive and metabolic constraints underlying LTM formation into a unified gating mechanism.
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Affiliation(s)
- Typhaine Comyn
- Energy & Memory, Brain Plasticity Unit, CNRS, ESPCI Paris, PSL Research University, 10 rue Vauquelin, 75005 Paris, France
| | - Thomas Preat
- Energy & Memory, Brain Plasticity Unit, CNRS, ESPCI Paris, PSL Research University, 10 rue Vauquelin, 75005 Paris, France
| | - Alice Pavlowsky
- Energy & Memory, Brain Plasticity Unit, CNRS, ESPCI Paris, PSL Research University, 10 rue Vauquelin, 75005 Paris, France
- Co-corresponding authors
| | - Pierre-Yves Plaçais
- Energy & Memory, Brain Plasticity Unit, CNRS, ESPCI Paris, PSL Research University, 10 rue Vauquelin, 75005 Paris, France
- Co-corresponding authors
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2
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Walker V. The Intricacies of Renal Phosphate Reabsorption-An Overview. Int J Mol Sci 2024; 25:4684. [PMID: 38731904 PMCID: PMC11083860 DOI: 10.3390/ijms25094684] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/24/2024] [Revised: 04/17/2024] [Accepted: 04/19/2024] [Indexed: 05/13/2024] Open
Abstract
To maintain an optimal body content of phosphorus throughout postnatal life, variable phosphate absorption from food must be finely matched with urinary excretion. This amazing feat is accomplished through synchronised phosphate transport by myriads of ciliated cells lining the renal proximal tubules. These respond in real time to changes in phosphate and composition of the renal filtrate and to hormonal instructions. How they do this has stimulated decades of research. New analytical techniques, coupled with incredible advances in computer technology, have opened new avenues for investigation at a sub-cellular level. There has been a surge of research into different aspects of the process. These have verified long-held beliefs and are also dramatically extending our vision of the intense, integrated, intracellular activity which mediates phosphate absorption. Already, some have indicated new approaches for pharmacological intervention to regulate phosphate in common conditions, including chronic renal failure and osteoporosis, as well as rare inherited biochemical disorders. It is a rapidly evolving field. The aim here is to provide an overview of our current knowledge, to show where it is leading, and where there are uncertainties. Hopefully, this will raise questions and stimulate new ideas for further research.
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Affiliation(s)
- Valerie Walker
- Department of Clinical Biochemistry, University Hospital Southampton NHS Foundation Trust, Southampton General Hospital, Southampton S016 6YD, UK
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3
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Channer B, Matt SM, Nickoloff-Bybel EA, Pappa V, Agarwal Y, Wickman J, Gaskill PJ. Dopamine, Immunity, and Disease. Pharmacol Rev 2023; 75:62-158. [PMID: 36757901 PMCID: PMC9832385 DOI: 10.1124/pharmrev.122.000618] [Citation(s) in RCA: 38] [Impact Index Per Article: 38.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/16/2022] [Revised: 08/02/2022] [Accepted: 08/04/2022] [Indexed: 12/14/2022] Open
Abstract
The neurotransmitter dopamine is a key factor in central nervous system (CNS) function, regulating many processes including reward, movement, and cognition. Dopamine also regulates critical functions in peripheral organs, such as blood pressure, renal activity, and intestinal motility. Beyond these functions, a growing body of evidence indicates that dopamine is an important immunoregulatory factor. Most types of immune cells express dopamine receptors and other dopaminergic proteins, and many immune cells take up, produce, store, and/or release dopamine, suggesting that dopaminergic immunomodulation is important for immune function. Targeting these pathways could be a promising avenue for the treatment of inflammation and disease, but despite increasing research in this area, data on the specific effects of dopamine on many immune cells and disease processes remain inconsistent and poorly understood. Therefore, this review integrates the current knowledge of the role of dopamine in immune cell function and inflammatory signaling across systems. We also discuss the current understanding of dopaminergic regulation of immune signaling in the CNS and peripheral tissues, highlighting the role of dopaminergic immunomodulation in diseases such as Parkinson's disease, several neuropsychiatric conditions, neurologic human immunodeficiency virus, inflammatory bowel disease, rheumatoid arthritis, and others. Careful consideration is given to the influence of experimental design on results, and we note a number of areas in need of further research. Overall, this review integrates our knowledge of dopaminergic immunology at the cellular, tissue, and disease level and prompts the development of therapeutics and strategies targeted toward ameliorating disease through dopaminergic regulation of immunity. SIGNIFICANCE STATEMENT: Canonically, dopamine is recognized as a neurotransmitter involved in the regulation of movement, cognition, and reward. However, dopamine also acts as an immune modulator in the central nervous system and periphery. This review comprehensively assesses the current knowledge of dopaminergic immunomodulation and the role of dopamine in disease pathogenesis at the cellular and tissue level. This will provide broad access to this information across fields, identify areas in need of further investigation, and drive the development of dopaminergic therapeutic strategies.
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Affiliation(s)
- Breana Channer
- Department of Pharmacology and Physiology, Drexel University College of Medicine, Philadelphia, Pennsylvania (B.C., S.M.M., E.A.N-B., Y.A., J.W., P.J.G.); and The Children's Hospital of Philadelphia Research Institute, Philadelphia, Pennsylvania (V.P.)
| | - Stephanie M Matt
- Department of Pharmacology and Physiology, Drexel University College of Medicine, Philadelphia, Pennsylvania (B.C., S.M.M., E.A.N-B., Y.A., J.W., P.J.G.); and The Children's Hospital of Philadelphia Research Institute, Philadelphia, Pennsylvania (V.P.)
| | - Emily A Nickoloff-Bybel
- Department of Pharmacology and Physiology, Drexel University College of Medicine, Philadelphia, Pennsylvania (B.C., S.M.M., E.A.N-B., Y.A., J.W., P.J.G.); and The Children's Hospital of Philadelphia Research Institute, Philadelphia, Pennsylvania (V.P.)
| | - Vasiliki Pappa
- Department of Pharmacology and Physiology, Drexel University College of Medicine, Philadelphia, Pennsylvania (B.C., S.M.M., E.A.N-B., Y.A., J.W., P.J.G.); and The Children's Hospital of Philadelphia Research Institute, Philadelphia, Pennsylvania (V.P.)
| | - Yash Agarwal
- Department of Pharmacology and Physiology, Drexel University College of Medicine, Philadelphia, Pennsylvania (B.C., S.M.M., E.A.N-B., Y.A., J.W., P.J.G.); and The Children's Hospital of Philadelphia Research Institute, Philadelphia, Pennsylvania (V.P.)
| | - Jason Wickman
- Department of Pharmacology and Physiology, Drexel University College of Medicine, Philadelphia, Pennsylvania (B.C., S.M.M., E.A.N-B., Y.A., J.W., P.J.G.); and The Children's Hospital of Philadelphia Research Institute, Philadelphia, Pennsylvania (V.P.)
| | - Peter J Gaskill
- Department of Pharmacology and Physiology, Drexel University College of Medicine, Philadelphia, Pennsylvania (B.C., S.M.M., E.A.N-B., Y.A., J.W., P.J.G.); and The Children's Hospital of Philadelphia Research Institute, Philadelphia, Pennsylvania (V.P.)
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4
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Dopamine Receptor Expression and the Pathogenesis of Attention-Deficit Hyperactivity Disorder: a Scoping Review of the Literature. CURRENT DEVELOPMENTAL DISORDERS REPORTS 2022. [DOI: 10.1007/s40474-022-00253-5] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/26/2022]
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5
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Matera C, Calvé P, Casadó-Anguera V, Sortino R, Gomila AMJ, Moreno E, Gener T, Delgado-Sallent C, Nebot P, Costazza D, Conde-Berriozabal S, Masana M, Hernando J, Casadó V, Puig MV, Gorostiza P. Reversible Photocontrol of Dopaminergic Transmission in Wild-Type Animals. Int J Mol Sci 2022; 23:ijms231710114. [PMID: 36077512 PMCID: PMC9456102 DOI: 10.3390/ijms231710114] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/03/2022] [Revised: 08/27/2022] [Accepted: 08/31/2022] [Indexed: 01/09/2023] Open
Abstract
Understanding the dopaminergic system is a priority in neurobiology and neuropharmacology. Dopamine receptors are involved in the modulation of fundamental physiological functions, and dysregulation of dopaminergic transmission is associated with major neurological disorders. However, the available tools to dissect the endogenous dopaminergic circuits have limited specificity, reversibility, resolution, or require genetic manipulation. Here, we introduce azodopa, a novel photoswitchable ligand that enables reversible spatiotemporal control of dopaminergic transmission. We demonstrate that azodopa activates D1-like receptors in vitro in a light-dependent manner. Moreover, it enables reversibly photocontrolling zebrafish motility on a timescale of seconds and allows separating the retinal component of dopaminergic neurotransmission. Azodopa increases the overall neural activity in the cortex of anesthetized mice and displays illumination-dependent activity in individual cells. Azodopa is the first photoswitchable dopamine agonist with demonstrated efficacy in wild-type animals and opens the way to remotely controlling dopaminergic neurotransmission for fundamental and therapeutic purposes.
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Affiliation(s)
- Carlo Matera
- Institute for Bioengineering of Catalonia (IBEC), the Barcelona Institute for Science and Technology, 08028 Barcelona, Spain
- Biomedical Research Networking Center in Bioengineering, Biomaterials and Nanomedicine (CIBER-BBN), 28029 Madrid, Spain
- Department of Pharmaceutical Sciences, University of Milan, 20133 Milan, Italy
| | - Pablo Calvé
- Hospital del Mar Medical Research Institute (IMIM), Barcelona Biomedical Research Park, 08003 Barcelona, Spain
| | - Verònica Casadó-Anguera
- Department of Biochemistry and Molecular Biomedicine, Faculty of Biology, Institute of Biomedicine, University of Barcelona, 08028 Barcelona, Spain
| | - Rosalba Sortino
- Institute for Bioengineering of Catalonia (IBEC), the Barcelona Institute for Science and Technology, 08028 Barcelona, Spain
- Biomedical Research Networking Center in Bioengineering, Biomaterials and Nanomedicine (CIBER-BBN), 28029 Madrid, Spain
| | - Alexandre M. J. Gomila
- Institute for Bioengineering of Catalonia (IBEC), the Barcelona Institute for Science and Technology, 08028 Barcelona, Spain
- Biomedical Research Networking Center in Bioengineering, Biomaterials and Nanomedicine (CIBER-BBN), 28029 Madrid, Spain
| | - Estefanía Moreno
- Department of Biochemistry and Molecular Biomedicine, Faculty of Biology, Institute of Biomedicine, University of Barcelona, 08028 Barcelona, Spain
| | - Thomas Gener
- Hospital del Mar Medical Research Institute (IMIM), Barcelona Biomedical Research Park, 08003 Barcelona, Spain
| | - Cristina Delgado-Sallent
- Hospital del Mar Medical Research Institute (IMIM), Barcelona Biomedical Research Park, 08003 Barcelona, Spain
| | - Pau Nebot
- Hospital del Mar Medical Research Institute (IMIM), Barcelona Biomedical Research Park, 08003 Barcelona, Spain
| | - Davide Costazza
- Institute for Bioengineering of Catalonia (IBEC), the Barcelona Institute for Science and Technology, 08028 Barcelona, Spain
| | - Sara Conde-Berriozabal
- Department of Biomedical Sciences, Faculty of Medicine and Health Sciences, Institute of Neuroscience, University of Barcelona, IDIBAPS, CIBERNED, 08036 Barcelona, Spain
| | - Mercè Masana
- Department of Biomedical Sciences, Faculty of Medicine and Health Sciences, Institute of Neuroscience, University of Barcelona, IDIBAPS, CIBERNED, 08036 Barcelona, Spain
| | - Jordi Hernando
- Department of Chemistry, Autonomous University of Barcelona (UAB), 08193 Cerdanyola del Vallès, Spain
| | - Vicent Casadó
- Department of Biochemistry and Molecular Biomedicine, Faculty of Biology, Institute of Biomedicine, University of Barcelona, 08028 Barcelona, Spain
| | - M. Victoria Puig
- Hospital del Mar Medical Research Institute (IMIM), Barcelona Biomedical Research Park, 08003 Barcelona, Spain
| | - Pau Gorostiza
- Institute for Bioengineering of Catalonia (IBEC), the Barcelona Institute for Science and Technology, 08028 Barcelona, Spain
- Biomedical Research Networking Center in Bioengineering, Biomaterials and Nanomedicine (CIBER-BBN), 28029 Madrid, Spain
- Catalan Institution for Research and Advanced Studies (ICREA), 08010 Barcelona, Spain
- Correspondence:
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Zhai R, Snyder J, Montgomery S, Sato PY. Double life: How GRK2 and β-arrestin signaling participate in diseases. Cell Signal 2022; 94:110333. [PMID: 35430346 PMCID: PMC9929935 DOI: 10.1016/j.cellsig.2022.110333] [Citation(s) in RCA: 7] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/30/2022] [Revised: 04/09/2022] [Accepted: 04/11/2022] [Indexed: 11/03/2022]
Abstract
G-protein coupled receptor (GPCR) kinases (GRKs) and β-arrestins play key roles in GPCR and non-GPCR cellular responses. In fact, GRKs and arrestins are involved in a plethora of pathways vital for physiological maintenance of inter- and intracellular communication. Here we review decades of research literature spanning from the discovery, identification of key structural elements, and findings supporting the diverse roles of these proteins in GPCR-mediated pathways. We then describe how GRK2 and β-arrestins partake in non-GPCR signaling and briefly summarize their involvement in various pathologies. We conclude by presenting gaps in knowledge and our prospective on the promising pharmacological potential in targeting these proteins and/or downstream signaling. Future research is warranted and paramount for untangling these novel and promising roles for GRK2 and arrestins in metabolism and disease progression.
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Affiliation(s)
| | | | | | - Priscila Y. Sato
- Corresponding author at: Drexel University College of Medicine, Department of Pharmacology and Physiology, 245 N 15th Street, NCB 8152, Philadelphia, PA 19102, USA. (P.Y. Sato)
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Characterization of dopamine D 2 receptor coupling to G proteins in postmortem brain of subjects with schizophrenia. Pharmacol Rep 2021; 73:1136-1146. [PMID: 34196951 PMCID: PMC8413194 DOI: 10.1007/s43440-021-00305-4] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/15/2021] [Revised: 06/16/2021] [Accepted: 06/24/2021] [Indexed: 11/04/2022]
Abstract
Background Alterations of dopamine D1 (D1R) and D2 receptor (D2R) are proposed in schizophrenia but brain neuroimaging and postmortem studies have shown controversial results in relation to D1R and D2R density. Besides, scarce information on the functionality of brain D1R and D2R is available. The present study characterized G-protein activation by D1R and D2R agonists in postmortem human brain. Furthermore, D2R functional status was compared between schizophrenia and control subjects. Methods G-protein receptor coupling was assessed in control caudate nucleus and frontal cortex by [35S]GTPγS-binding stimulation induced by increasing concentrations (10–10–10–3 M) of dopamine, and the selective dopaminergic agonists SKF38393 (D1R) and NPA (D2R). Concentration–response curves to NPA stimulation of [35S]GTPγS binding were analyzed in antipsychotic-free (n = 10) and antipsychotic-treated (n = 7) schizophrenia subjects and matched controls (n = 17). Results In caudate, [35S]GTPγS-binding responses to agonists were compatible with the existence of functional D2R. In contrast, stimulations in cortex showed responses that did not correspond to D1R or D2R. [35S]GTPγS-binding activation by NPA in caudate displayed biphasic curves with similar profile in schizophrenia (EC50H = 7.94 nM; EC50L = 7.08 μM) and control (EC50H = 7.24 nM; EC50L = 15.14 μM) subjects. The presence or absence of antipsychotic medication did not influence the pharmacological parameters. Conclusions Feasibility of functional evaluation of dopamine receptors in postmortem human brain by conventional [35S]GTPγS-binding assays appears to be restricted to signalling through inhibitory Gi/o proteins. These findings provide functional information about brain D2R status in subjects with schizophrenia and do not support the existence of D2R supersensitive in this mental disorder. Supplementary Information The online version contains supplementary material available at 10.1007/s43440-021-00305-4.
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8
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Functional approaches to the study of G-protein-coupled receptors in postmortem brain tissue: [ 35S]GTPγS binding assays combined with immunoprecipitation. Pharmacol Rep 2021; 73:1079-1095. [PMID: 33876404 DOI: 10.1007/s43440-021-00253-z] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/08/2021] [Revised: 03/16/2021] [Accepted: 03/19/2021] [Indexed: 10/21/2022]
Abstract
G-protein-coupled receptors (GPCRs) have an enormous biochemical importance as they bind to diverse extracellular ligands and regulate a variety of physiological and pathological responses. G-protein activation measures the functional consequence of receptor occupancy at one of the earliest receptor-mediated events. Receptor coupling to G-proteins promotes the GDP/GTP exchange on Gα subunits. Thus, modulation of the binding of the poorly hydrolysable GTP analog [35S]GTPγS to the Gα-protein subunit can be used as a functional approach to quantify GPCR interaction with agonist, antagonist or inverse agonist drugs. In order to determine receptor-mediated selective activation of the different Gα-proteins, [35S]GTPγS binding assays combined with immunodetection by specific antibodies have been developed and applied to physiological and pathological brain conditions. Currently, immunoprecipitation with magnetic beads and scintillation proximity assays are the most habitual techniques for this purpose. The present review summarizes the different procedures, advantages and limitations of the [35S]GTPγS binding assays combined with selective Gα-protein sequestration methods. Experience of functional coupling of several GPCRs to different Gα-proteins and recommendations for optimal performance in brain membranes are described. One of the biggest opportunities opened by these techniques is that they enable evaluation of biased agonism in the native tissue, which results in high interest in drug discovery. The available results derived from application of these functional methodologies to study GPCR dysfunctions in neuro-psychiatric disorders are also described. In conclusion, [35S]GTPγS binding combined with antibody-mediated immunodetection represents an useful method to separately evaluate the functional activity of drugs acting on GPCRs over each Gα-protein subtype.
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Tao JH, Gong XY, Cao YL, Zhang QY, Jing SS, Wang H, Chen YG. Mechanism of barley malt-dependent DRD2 to treat hyperprolactinemia based on UPLC-Q-TOF/MS and network pharmacology. Eur J Integr Med 2021. [DOI: 10.1016/j.eujim.2021.101322] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/25/2023]
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10
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Lipid Rafts and Dopamine Receptor Signaling. Int J Mol Sci 2020; 21:ijms21238909. [PMID: 33255376 PMCID: PMC7727868 DOI: 10.3390/ijms21238909] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/30/2020] [Revised: 11/18/2020] [Accepted: 11/20/2020] [Indexed: 02/07/2023] Open
Abstract
The renal dopaminergic system has been identified as a modulator of sodium balance and blood pressure. According to the Centers for Disease Control and Prevention, in 2018 in the United States, almost half a million deaths included hypertension as a primary or contributing cause. Renal dopamine receptors, members of the G protein-coupled receptor family, are divided in two groups: D1-like receptors that act to keep the blood pressure in the normal range, and D2-like receptors with a variable effect on blood pressure, depending on volume status. The renal dopamine receptor function is regulated, in part, by its expression in microdomains in the plasma membrane. Lipid rafts form platforms within the plasma membrane for the organization and dynamic contact of molecules involved in numerous cellular processes such as ligand binding, membrane sorting, effector specificity, and signal transduction. Understanding all the components of lipid rafts, their interaction with renal dopamine receptors, and their signaling process offers an opportunity to unravel potential treatment targets that could halt the progression of hypertension, chronic kidney disease (CKD), and their complications.
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11
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Dopamine modulates individual differences in avoidance behavior: A pharmacological, immunohistochemical, neurochemical and volumetric investigation. Neurobiol Stress 2020; 12:100219. [PMID: 32435668 PMCID: PMC7231994 DOI: 10.1016/j.ynstr.2020.100219] [Citation(s) in RCA: 17] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/14/2019] [Revised: 03/27/2020] [Accepted: 03/30/2020] [Indexed: 12/22/2022] Open
Abstract
Avoidance behavior is a hallmark in pathological anxiety disorders and results in impairment of daily activities. Individual differences in avoidance responses are critical in determining vulnerability or resistance to anxiety disorders. Dopaminergic activation is implicated in the processing of avoidance responses; however, the mechanisms underlying these responses are unknown. In this sense, we used a preclinical model of avoidance behavior to investigate the possibility of an intrinsic differential dopaminergic pattern between good and poor performers. The specific goal was to assess the participation of dopamine (DA) through pharmacological manipulation, and we further evaluated the effects of systemic injections of the dopaminergic receptor type 1 (D1 antagonist - SCH23390) and dopaminergic receptor type 2 (D2 antagonist - sulpiride) antagonists in the good performers. Additionally, we evaluated the effects of intra-amygdala microinjection of a D1 antagonist (SCH23390) and a D2 antagonist (sulpiride) in good performers as well as intra-amygdala microinjection of a D1 agonist (SKF38393) and D2 agonist (quinpirole) in poor performers. Furthermore, we quantified the contents of dopamine and metabolites (3,4-dihydroxyphenylacetic acid (DOPAC) and homovanillic acid (HVA)) in the amygdala, evaluated the basal levels of tyrosine hydroxylase expression (catecholamine synthesis enzyme) and measured the volume of the substantia nigra, ventral tegmental area and locus coeruleus. Our results showed that it could be possible to convert animals from good to poor performers, and vice versa, by intra-amygdala (basolateral and central nucleus) injections of D1 receptor antagonists in good performers or D2 receptor agonists in poor performers. Additionally, the good performers had lower levels of DOPAC and HVA in the amygdala, an increase in the total volume of the amygdala (AMG), substantia nigra (SN), ventral tegmental area (VTA) and locus coeruleus (LC), and an increase in the number of tyrosine hydroxylase-positive cells in SN, VTA and LC, which positively correlates with the avoidance behavior. Taken together, our data show evidence for a dopaminergic signature of avoidance performers, emphasizing the role of distinct dopaminergic receptors in individual differences in avoidance behavior based on pharmacological, immunohistochemical, neurochemical and volumetric analyses. Our findings provide a better understanding of the role of the dopaminergic system in the execution of avoidance behavior. The role of dopamine in individual differences in avoidance behavior. Dopamine modulates avoidance behavior. Dopaminergic evidence of individual difference in avoidance behavior. Good and poor avoiders distinction based on dopaminergic signature. Dopaminergic signature of avoidance performers: poor versus good avoiders.
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Differential Signaling Profiles of MC4R Mutations with Three Different Ligands. Int J Mol Sci 2020; 21:ijms21041224. [PMID: 32059383 PMCID: PMC7072973 DOI: 10.3390/ijms21041224] [Citation(s) in RCA: 13] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/19/2019] [Revised: 02/06/2020] [Accepted: 02/06/2020] [Indexed: 12/21/2022] Open
Abstract
The melanocortin 4 receptor (MC4R) is a key player in hypothalamic weight regulation and energy expenditure as part of the leptin–melanocortin pathway. Mutations in this G protein coupled receptor (GPCR) are the most common cause for monogenetic obesity, which appears to be mediated by changes in the anorectic action of MC4R via GS-dependent cyclic adenosine-monophosphate (cAMP) signaling as well as other signaling pathways. To study potential bias in the effects of MC4R mutations between the different signaling pathways, we investigated three major MC4R mutations: a GS loss-of-function (S127L) and a GS gain-of-function mutant (H158R), as well as the most common European single nucleotide polymorphism (V103I). We tested signaling of all four major G protein families plus extracellular regulated kinase (ERK) phosphorylation and β-arrestin2 recruitment, using the two endogenous agonists, α- and β-melanocyte stimulating hormone (MSH), along with a synthetic peptide agonist (NDP-α-MSH). The S127L mutation led to a full loss-of-function in all investigated pathways, whereas V103I and H158R were clearly biased towards the Gq/11 pathway when challenged with the endogenous ligands. These results show that MC4R mutations can cause vastly different changes in the various MC4R signaling pathways and highlight the importance of a comprehensive characterization of receptor mutations.
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Nickoloff E, Mackie P, Runner K, Matt S, Khoshbouei H, Gaskill P. Dopamine increases HIV entry into macrophages by increasing calcium release via an alternative signaling pathway. Brain Behav Immun 2019; 82:239-252. [PMID: 31470080 PMCID: PMC6941734 DOI: 10.1016/j.bbi.2019.08.191] [Citation(s) in RCA: 18] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 01/29/2019] [Revised: 08/22/2019] [Accepted: 08/26/2019] [Indexed: 12/19/2022] Open
Abstract
Dopaminergic dysfunction has long been connected to the development of HIV infection in the CNS. Our previous data showed that dopamine increases HIV infection in human macrophages by increasing the susceptibility of primary human macrophages to HIV entry through stimulation of both D1-like and D2-like receptors. These data suggest that, in macrophages, both dopamine receptor subtypes may act through a common signaling mechanism. To define better the mechanism(s) underlying this effect, this study examines the specific signaling processes activated by dopamine in primary human monocyte-derived macrophages (hMDM). In addition to confirming that the increase in entry is unique to dopamine, these studies show that dopamine increases HIV entry through a PKA insensitive, Ca2+ dependent pathway. Further examination demonstrated that dopamine can signal through a previously defined, non-canonical pathway in human macrophages. This pathway involves both Ca2+ release and PKC phosphorylation, and these data show that dopamine mediates both of these effects and that both were partially inhibited by the Gq/11 specific inhibitor YM-254890. Studies have shown that Gq/11 preferentially couples to the D1-like receptor D5, indicating an important role of the D1-like receptors in mediating these effects. These data indicate a role for Ca2+ flux in the HIV entry process, and suggest a distinct signaling mechanism mediating some of the effects of dopamine in macrophages. Together, the data indicate that targeting this alternative dopamine signaling pathway might provide new therapeutic options for individuals with elevated CNS dopamine suffering from NeuroHIV.
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Affiliation(s)
- E.A. Nickoloff
- Department of Pharmacology and Physiology, Drexel University College of Medicine, Philadelphia, PA, 19102
| | - P. Mackie
- Department of Neuroscience, University of Florida, Gainesville, FL, 32611
| | - K. Runner
- Department of Pharmacology and Physiology, Drexel University College of Medicine, Philadelphia, PA, 19102
| | - S.M. Matt
- Department of Pharmacology and Physiology, Drexel University College of Medicine, Philadelphia, PA, 19102
| | - H. Khoshbouei
- Department of Neuroscience, University of Florida, Gainesville, FL, 32611,Department of Psychiatry, University of Florida, Gainesville, FL, 32611
| | - P.J. Gaskill
- Department of Pharmacology and Physiology, Drexel University College of Medicine, Philadelphia, PA, 19102
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Colom M, Vidal B, Zimmer L. Is There a Role for GPCR Agonist Radiotracers in PET Neuroimaging? Front Mol Neurosci 2019; 12:255. [PMID: 31680859 PMCID: PMC6813225 DOI: 10.3389/fnmol.2019.00255] [Citation(s) in RCA: 22] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/25/2019] [Accepted: 10/02/2019] [Indexed: 12/30/2022] Open
Abstract
Positron emission tomography (PET) is a molecular imaging modality that enables in vivo exploration of metabolic processes and especially the pharmacology of neuroreceptors. G protein-coupled receptors (GPCRs) play an important role in numerous pathophysiologic disorders of the central nervous system. Thus, they are targets of choice in PET imaging to bring proof concept of change in density in pathological conditions or in pharmacological challenge. At present, most radiotracers are antagonist ligands. In vitro data suggest that properties differ between GPCR agonists and antagonists: antagonists bind to receptors with a single affinity, whereas agonists are characterized by two different affinities: high affinity for receptors that undergo functional coupling to G-proteins, and low affinity for those that are not coupled. In this context, agonist radiotracers may be useful tools to give functional images of GPCRs in the brain, with high sensitivity to neurotransmitter release. Here, we review all existing PET radiotracers used from animals to humans and their role for understanding the ligand-receptor paradigm of GPCR in comparison with corresponding antagonist radiotracers.
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Affiliation(s)
- Matthieu Colom
- Lyon Neuroscience Research Center, INSERM, CNRS, Université de Lyon, Lyon, France.,CERMEP, Hospices Civils de Lyon, Bron, France
| | - Benjamin Vidal
- Lyon Neuroscience Research Center, INSERM, CNRS, Université de Lyon, Lyon, France
| | - Luc Zimmer
- Lyon Neuroscience Research Center, INSERM, CNRS, Université de Lyon, Lyon, France.,CERMEP, Hospices Civils de Lyon, Bron, France.,Institut National des Sciences et Techniques Nucléaires, CEA Saclay, Gif-sur-Yvette, France
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15
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Odagaki Y, Kinoshita M, Ota T. Dopamine-induced functional activation of Gα q mediated by dopamine D 1-like receptor in rat cerebral cortical membranes. J Recept Signal Transduct Res 2019; 39:9-17. [PMID: 31223051 DOI: 10.1080/10799893.2018.1562470] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/23/2022]
Abstract
Although multiple roles of dopamine through D1-like (D1 and D5) and D2-like (D2, D3, and D4) receptors are initiated primarily through stimulation or inhibition of adenylyl cyclase via Gs/olf or Gi/o, respectively, there have been many reports indicating diverse signaling mechanisms that involve alternative G protein coupling. In this study, dopamine-induced Gαq activation in rat brain membranes was investigated. Agonist-induced Gαq activation was assessed by increase in guanosine-5'-O-(3-[35S]thio)triphosphate ([35S]GTPγS) binding to Gαq determined by [35S]GTPγS binding/immunoprecipitation assay in rat brain membranes. Dopamine-stimulated Gαq functionality was highest in cortex as compared to hippocampus or striatum. In cerebral cortical membranes, this effect was mimicked by benzazepine derivatives with agonist properties at dopamine D1-like receptors, that is, SKF83959, SKF83822, R(+)-SKF81297, R(+)-SKF38393, and SKF82958, but not by the compounds with dopamine D2-like receptor agonist properties except for aripiprazole. Against expectation, stimulatory effects were also induced by SKF83566, R(+)-SCH23390, and pergolide. The pharmacological profiling by using a series of antagonists indicated that dopamine-induced response was mediated through dopamine D1-like receptor, which was distinct from the receptor involved in 5-HT-induced response (5-HT2A receptor). Conversely, the responses induced by SKF83566, R(+)-SCH23390, and pergolide were most likely mediated by 5-HT2A receptor, but not by dopamine D1-like receptor. Caution should be paid when interpreting the experimental data, especially in behavioral pharmacological research, in which SKF83566 or R(+)-SCH23390 is used as a standard selective dopamine D1-like receptor antagonist. Also, possible clinical implications of the agonistic effects of pergolide on 5-HT2A receptor has been mentioned.
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Affiliation(s)
- Yuji Odagaki
- a Department of Psychiatry, Faculty of Medicine , Saitama Medical University , Saitama , Japan
| | - Masakazu Kinoshita
- a Department of Psychiatry, Faculty of Medicine , Saitama Medical University , Saitama , Japan
| | - Toshio Ota
- a Department of Psychiatry, Faculty of Medicine , Saitama Medical University , Saitama , Japan
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16
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Where Is Dopamine and how do Immune Cells See it?: Dopamine-Mediated Immune Cell Function in Health and Disease. J Neuroimmune Pharmacol 2019; 15:114-164. [PMID: 31077015 DOI: 10.1007/s11481-019-09851-4] [Citation(s) in RCA: 123] [Impact Index Per Article: 24.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/08/2019] [Accepted: 04/07/2019] [Indexed: 02/07/2023]
Abstract
Dopamine is well recognized as a neurotransmitter in the brain, and regulates critical functions in a variety of peripheral systems. Growing research has also shown that dopamine acts as an important regulator of immune function. Many immune cells express dopamine receptors and other dopamine related proteins, enabling them to actively respond to dopamine and suggesting that dopaminergic immunoregulation is an important part of proper immune function. A detailed understanding of the physiological concentrations of dopamine in specific regions of the human body, particularly in peripheral systems, is critical to the development of hypotheses and experiments examining the effects of physiologically relevant dopamine concentrations on immune cells. Unfortunately, the dopamine concentrations to which these immune cells would be exposed in different anatomical regions are not clear. To address this issue, this comprehensive review details the current information regarding concentrations of dopamine found in both the central nervous system and in many regions of the periphery. In addition, we discuss the immune cells present in each region, and how these could interact with dopamine in each compartment described. Finally, the review briefly addresses how changes in these dopamine concentrations could influence immune cell dysfunction in several disease states including Parkinson's disease, multiple sclerosis, rheumatoid arthritis, inflammatory bowel disease, as well as the collection of pathologies, cognitive and motor symptoms associated with HIV infection in the central nervous system, known as NeuroHIV. These data will improve our understanding of the interactions between the dopaminergic and immune systems during both homeostatic function and in disease, clarify the effects of existing dopaminergic drugs and promote the creation of new therapeutic strategies based on manipulating immune function through dopaminergic signaling. Graphical Abstract.
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17
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Seyedabadi M, Ghahremani MH, Albert PR. Biased signaling of G protein coupled receptors (GPCRs): Molecular determinants of GPCR/transducer selectivity and therapeutic potential. Pharmacol Ther 2019; 200:148-178. [PMID: 31075355 DOI: 10.1016/j.pharmthera.2019.05.006] [Citation(s) in RCA: 88] [Impact Index Per Article: 17.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/15/2019] [Accepted: 04/26/2019] [Indexed: 02/07/2023]
Abstract
G protein coupled receptors (GPCRs) convey signals across membranes via interaction with G proteins. Originally, an individual GPCR was thought to signal through one G protein family, comprising cognate G proteins that mediate canonical receptor signaling. However, several deviations from canonical signaling pathways for GPCRs have been described. It is now clear that GPCRs can engage with multiple G proteins and the line between cognate and non-cognate signaling is increasingly blurred. Furthermore, GPCRs couple to non-G protein transducers, including β-arrestins or other scaffold proteins, to initiate additional signaling cascades. Receptor/transducer selectivity is dictated by agonist-induced receptor conformations as well as by collateral factors. In particular, ligands stabilize distinct receptor conformations to preferentially activate certain pathways, designated 'biased signaling'. In this regard, receptor sequence alignment and mutagenesis have helped to identify key receptor domains for receptor/transducer specificity. Furthermore, molecular structures of GPCRs bound to different ligands or transducers have provided detailed insights into mechanisms of coupling selectivity. However, receptor dimerization, compartmentalization, and trafficking, receptor-transducer-effector stoichiometry, and ligand residence and exposure times can each affect GPCR coupling. Extrinsic factors including cell type or assay conditions can also influence receptor signaling. Understanding these factors may lead to the development of improved biased ligands with the potential to enhance therapeutic benefit, while minimizing adverse effects. In this review, evidence for ligand-specific GPCR signaling toward different transducers or pathways is elaborated. Furthermore, molecular determinants of biased signaling toward these pathways and relevant examples of the potential clinical benefits and pitfalls of biased ligands are discussed.
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Affiliation(s)
- Mohammad Seyedabadi
- Department of Pharmacology, School of Medicine, Bushehr University of Medical Sciences, Iran; Education Development Center, Bushehr University of Medical Sciences, Iran
| | | | - Paul R Albert
- Ottawa Hospital Research Institute, Neuroscience, University of Ottawa, Canada.
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18
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Cahill EN, Milton AL. Neurochemical and molecular mechanisms underlying the retrieval-extinction effect. Psychopharmacology (Berl) 2019; 236:111-132. [PMID: 30656364 PMCID: PMC6373198 DOI: 10.1007/s00213-018-5121-3] [Citation(s) in RCA: 33] [Impact Index Per Article: 6.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 07/28/2018] [Accepted: 11/12/2018] [Indexed: 12/26/2022]
Abstract
Extinction within the reconsolidation window, or 'retrieval-extinction', has received much research interest as a possible technique for targeting the reconsolidation of maladaptive memories with a behavioural intervention. However, it remains to be determined whether the retrieval-extinction effect-a long-term reduction in fear behaviour, which appears resistant to spontaneous recovery, renewal and reinstatement-depends specifically on destabilisation of the original memory (the 'reconsolidation-update' account) or represents facilitation of an extinction memory (the 'extinction-facilitation' account). We propose that comparing the neurotransmitter systems, receptors and intracellular signalling pathways recruited by reconsolidation, extinction and retrieval-extinction will provide a way of distinguishing between these accounts.
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Affiliation(s)
- Emma N. Cahill
- Department of Physiology, Development and Neuroscience, University of Cambridge, Downing Site, Cambridge, CB2 3EG UK
| | - Amy L. Milton
- Department of Psychology, University of Cambridge, Downing Site, Cambridge, CB2 3EB UK ,Behavioural and Clinical Neuroscience Institute, Cambridge, CB2 3EB UK
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19
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Finlay DB, Cawston EE, Grimsey NL, Hunter MR, Korde A, Vemuri VK, Makriyannis A, Glass M. Gα s signalling of the CB 1 receptor and the influence of receptor number. Br J Pharmacol 2017; 174:2545-2562. [PMID: 28516479 PMCID: PMC5513864 DOI: 10.1111/bph.13866] [Citation(s) in RCA: 64] [Impact Index Per Article: 9.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/22/2016] [Revised: 04/30/2017] [Accepted: 05/09/2017] [Indexed: 01/19/2023] Open
Abstract
BACKGROUND AND PURPOSE CB1 receptor signalling is canonically mediated through inhibitory Gαi proteins, but occurs through other G proteins under some circumstances, Gαs being the most characterized secondary pathway. Determinants of this signalling switch identified to date include Gαi blockade, CB1 /D2 receptor co-stimulation, CB1 agonist class and cell background. Hence, we examined the effects of receptor number and different ligands on CB1 receptor signalling. EXPERIMENTAL APPROACH CB1 receptors were expressed in HEK cells at different levels, and signalling characterized for cAMP by real-time BRET biosensor -CAMYEL - and for phospho-ERK by AlphaScreen. Homogenate and whole cell radioligand binding assays were performed to characterize AM6544, a novel irreversible CB1 receptor antagonist. KEY RESULTS In HEK cells expressing high levels of CB1 receptors, agonist treatment stimulated cAMP, a response not known to be mediated by receptor number. Δ9 -THC and BAY59-3074 increased cAMP only in high-expressing cells pretreated with pertussis toxin, and agonists demonstrated more diverse signalling profiles in the stimulatory pathway than the canonical inhibitory pathway. Pharmacological CB1 receptor knockdown and Gαi 1 supplementation restored canonical Gαi signalling to high-expressing cells. Constitutive signalling in both low- and high-expressing cells was Gαi -mediated. CONCLUSION AND IMPLICATIONS CB1 receptor coupling to opposing G proteins is determined by both receptor and G protein expression levels, which underpins a mechanism for non-canonical signalling in a fashion consistent with Gαs signalling. CB1 receptors mediate opposite consequences in endpoints such as tumour viability depending on expression levels; our results may help to explain such effects at the level of G protein coupling.
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Affiliation(s)
- David B Finlay
- Department of Pharmacology and Clinical Pharmacology, Faculty of Medical and Health SciencesUniversity of AucklandAucklandNew Zealand
| | - Erin E Cawston
- Department of Pharmacology and Clinical Pharmacology, Faculty of Medical and Health SciencesUniversity of AucklandAucklandNew Zealand
| | - Natasha L Grimsey
- Department of Pharmacology and Clinical Pharmacology, Faculty of Medical and Health SciencesUniversity of AucklandAucklandNew Zealand
| | - Morag R Hunter
- Department of Pharmacology and Clinical Pharmacology, Faculty of Medical and Health SciencesUniversity of AucklandAucklandNew Zealand
| | - Anisha Korde
- Center for Drug DiscoveryNortheastern UniversityBostonMAUSA
| | - V Kiran Vemuri
- Center for Drug DiscoveryNortheastern UniversityBostonMAUSA
| | | | - Michelle Glass
- Department of Pharmacology and Clinical Pharmacology, Faculty of Medical and Health SciencesUniversity of AucklandAucklandNew Zealand
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20
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Lai W, Cai Y, Zhou J, Chen S, Qin C, Yang C, Liu J, Xie X, Du C. Deficiency of the G protein Gαq ameliorates experimental autoimmune encephalomyelitis with impaired DC-derived IL-6 production and Th17 differentiation. Cell Mol Immunol 2017; 14:557-567. [PMID: 28216651 DOI: 10.1038/cmi.2016.65] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/23/2016] [Revised: 11/03/2016] [Accepted: 11/03/2016] [Indexed: 12/26/2022] Open
Abstract
Many G protein-coupled receptors (GPCRs) are reported to be involved in the pathogenesis of multiple sclerosis (MS), and ~40% of all identified GPCRs rely on the Gαq/11 G protein family to stimulate inositol lipid signaling. However, the function of Gα subunits in MS pathogenesis is still unknown. In this study, we attempted to determine the role of Gαq in the pathogenesis of experimental autoimmune encephalomyelitis (EAE), a well-known mouse model of MS. We discovered that compared with wild-type mice, Gαq-knockout mice exhibited less severe EAE symptoms, with lower clinical scores, reduced leukocyte infiltration and less extensive demyelination. Moreover, a significantly lower percentage of Th17 cells, one of the key players in MS pathogenesis, was observed in Gαq-knockout EAE mice. Studies in vitro demonstrated that deficiency of Gαq in CD4+ T cells directly impaired Th17 differentiation. In addition, deficiency of Gαq significantly impaired DC-derived IL-6 production, thus inhibiting Th17 differentiation and the Gαq-PLCβ-PKC and Gαq-MAPKs signaling pathways involved in the reduced IL-6 production by DCs. In summary, our data highlighted the critical role of Gαq in regulating Th17 differentiation and MS pathogenesis.
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Affiliation(s)
- Weiming Lai
- Department of Central Laboratory, Shanghai Tenth People's Hospital of Tongji University, School of Life Sciences and Technology, Tongji University, Shanghai 200092, China
| | - Yingying Cai
- Department of Central Laboratory, Shanghai Tenth People's Hospital of Tongji University, School of Life Sciences and Technology, Tongji University, Shanghai 200092, China
| | - Jinfeng Zhou
- Department of Central Laboratory, Shanghai Tenth People's Hospital of Tongji University, School of Life Sciences and Technology, Tongji University, Shanghai 200092, China
| | - Shuai Chen
- Department of Central Laboratory, Shanghai Tenth People's Hospital of Tongji University, School of Life Sciences and Technology, Tongji University, Shanghai 200092, China
| | - Chaoyan Qin
- Department of Central Laboratory, Shanghai Tenth People's Hospital of Tongji University, School of Life Sciences and Technology, Tongji University, Shanghai 200092, China
| | - Cuixia Yang
- Department of Central Laboratory, Shanghai Tenth People's Hospital of Tongji University, School of Life Sciences and Technology, Tongji University, Shanghai 200092, China
| | - Junling Liu
- Department of Biochemistry and Molecular Cell Biology, Shanghai Jiao Tong University School of Medicine, Shanghai 200025, China
| | - Xin Xie
- National Center for Drug Screening, CAS Key Laboratory of Receptor Research, Chinese Academy of Sciences, Shanghai Institute of Materia Medica, Shanghai 201203, China
| | - Changsheng Du
- Department of Central Laboratory, Shanghai Tenth People's Hospital of Tongji University, School of Life Sciences and Technology, Tongji University, Shanghai 200092, China.,Shanghai Key Laboratory of Signaling and Disease Research, School of Life Sciences and Technology, Tongji University, Shanghai 200092, China
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21
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Lau KM, Ma FMT, Xia JT, Chan QKY, Ng CF, To KF. Activation of GPR30 stimulates GTP-binding of Gαi1 protein to sustain activation of Erk1/2 in inhibition of prostate cancer cell growth and modulates metastatic properties. Exp Cell Res 2016; 350:199-209. [PMID: 27908592 DOI: 10.1016/j.yexcr.2016.11.022] [Citation(s) in RCA: 16] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/08/2016] [Revised: 11/11/2016] [Accepted: 11/27/2016] [Indexed: 12/27/2022]
Abstract
Previously, we reported that GPR30 activation by the receptor-specific, non-estrogenic ligand G-1 inhibited in vitro and in vivo growth of prostate cancer (PCa) cells via sustained Erk1/2 activation. Mechanism underlying the sustained Erk1/2 activation for PCa cell growth inhibition remains unclear. Here we report that G-1, through GPR30, activated Gαi1 proteins to sustain Erk1/2 activation but failed to activate adenylyl cyclase (AC) for cAMP production in PCa cells. The chemical-induced activation of AC-cAMP-PKA signaling attenuated Erk1/2 activity and blocked the cell growth inhibitory effects of G-1. Furthermore, PCa predominantly expressed Gαi1 proteins. Silencing of Gαi1 expression blocked the inhibitory effects of G-1 on PCa cell growth. By gene expression profiling, GPR30 activation by G-1 interfered expression of cell cycle regulators and machinery elements to modulate PCa cell growth and the RACGAP1 interactome to control metastatic properties. In this regard, we demonstrated that G-1 inhibited PCa cell migration and invasion with reduced formations of filopodia and stress fibers through a GPR30-dependent pathway. Taken together, our findings revealed the underlying mechanism for sustaining Erk1/2 activation upon GPR30 activation by G-1 in PCa cells and the GPR30-mediated pathways in controlling PCa cell growth and metastatic properties.
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Affiliation(s)
- Kin-Mang Lau
- Department of Anatomical and Cellular Pathology, The Chinese University of Hong Kong, Hong Kong Special Administrative Region, China.
| | - Fanny Man-Ting Ma
- Department of Anatomical and Cellular Pathology, The Chinese University of Hong Kong, Hong Kong Special Administrative Region, China
| | - Jenny Tian Xia
- Department of Anatomical and Cellular Pathology, The Chinese University of Hong Kong, Hong Kong Special Administrative Region, China
| | - Queeny Kwan Yi Chan
- Department of Anatomical and Cellular Pathology, The Chinese University of Hong Kong, Hong Kong Special Administrative Region, China
| | - Chi-Fai Ng
- Division of Urology, Department of Surgery, The Chinese University of Hong Kong, Hong Kong Special Administrative Region, China
| | - Ka-Fai To
- Department of Anatomical and Cellular Pathology, The Chinese University of Hong Kong, Hong Kong Special Administrative Region, China.
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22
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Li YQ, Shrestha Y, Pandey M, Chen M, Kablan A, Gavrilova O, Offermanns S, Weinstein LS. G(q/11)α and G(s)α mediate distinct physiological responses to central melanocortins. J Clin Invest 2015; 126:40-9. [PMID: 26595811 DOI: 10.1172/jci76348] [Citation(s) in RCA: 68] [Impact Index Per Article: 7.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/18/2015] [Accepted: 10/15/2015] [Indexed: 11/17/2022] Open
Abstract
Activation of brain melanocortin 4 receptors (MC4Rs) leads to reduced food intake, increased energy expenditure, increased insulin sensitivity, and reduced linear growth. MC4R effects on energy expenditure and glucose metabolism are primarily mediated by the G protein G(s)α in brain regions outside of the paraventricular nucleus of the hypothalamus (PVN). However, the G protein(s) that is involved in MC4R-mediated suppression of food intake and linear growth, which are believed to be regulated primarily though action in the PVN, is unknown. Here, we show that PVN-specific loss of G(q)α and G11α, which stimulate PLC, leads to severe hyperphagic obesity, increased linear growth, and inactivation of the hypothalamic-pituitary-adrenal axis, without affecting energy expenditure or glucose metabolism. Moreover, we demonstrate that the ability of an MC4R agonist delivered to PVN to inhibit food intake is lost in mice lacking G(q/11)α in the PVN but not in animals deficient for G(s)α. The blood pressure response to the same MC4R agonist was only lost in animals lacking G(s)α specifically in the PVN. Together, our results exemplify how different physiological effects of GPCRs may be mediated by different G proteins and identify a pathway for appetite regulation that could be selectively targeted by G(q/11)α-biased MC4R agonists as a potential treatment for obesity.
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23
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Hints on the Lateralization of Dopamine Binding to D1 Receptors in Rat Striatum. Mol Neurobiol 2015; 53:5436-45. [DOI: 10.1007/s12035-015-9468-8] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/03/2015] [Accepted: 09/29/2015] [Indexed: 10/23/2022]
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24
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Valentin-Hansen L, Frimurer TM, Mokrosinski J, Holliday ND, Schwartz TW. Biased Gs versus Gq proteins and β-arrestin signaling in the NK1 receptor determined by interactions in the water hydrogen bond network. J Biol Chem 2015; 290:24495-508. [PMID: 26269596 DOI: 10.1074/jbc.m115.641944] [Citation(s) in RCA: 27] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/02/2015] [Indexed: 11/06/2022] Open
Abstract
X-ray structures, molecular dynamics simulations, and mutational analysis have previously indicated that an extended water hydrogen bond network between trans-membranes I-III, VI, and VII constitutes an allosteric interface essential for stabilizing different active and inactive helical constellations during the seven-trans-membrane receptor activation. The neurokinin-1 receptor signals efficiently through Gq, Gs, and β-arrestin when stimulated by substance P, but it lacks any sign of constitutive activity. In the water hydrogen bond network the neurokinin-1 has a unique Glu residue instead of the highly conserved AspII:10 (2.50). Here, we find that this GluII:10 occupies the space of a putative allosteric modulating Na(+) ion and makes direct inter-helical interactions in particular with SerIII:15 (3.39) and AsnVII:16 (7.49) of the NPXXY motif. Mutational changes in the interface between GluII:10 and AsnVII:16 created receptors that selectively signaled through the following: 1) Gq only; 2) β-arrestin only; and 3) Gq and β-arrestin but not through Gs. Interestingly, increased constitutive Gs but not Gq signaling was observed by Ala substitution of four out of the six core polar residues of the network, in particular SerIII:15. Three residues were essential for all three signaling pathways, i.e. the water-gating micro-switch residues TrpVI:13 (6.48) of the CWXP motif and TyrVII:20 (7.53) of the NPXXY motif plus the totally conserved AsnI:18 (1.50) stabilizing the kink in trans-membrane VII. It is concluded that the interface between position II:10 (2.50), III:15 (3.39), and VII:16 (7.49) in the center of the water hydrogen bond network constitutes a focal point for fine-tuning seven trans-membrane receptor conformations activating different signal transduction pathways.
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Affiliation(s)
- Louise Valentin-Hansen
- From the Laboratory for Molecular Pharmacology, Department of Neuroscience and Pharmacology, The Panum Institute, Novo Nordisk Foundation Center for Basic Metabolic Research, and
| | - Thomas M Frimurer
- Novo Nordisk Foundation Center for Protein Research,University of Copenhagen, Blegdamsvej 3, 2200 Copenhagen, Denmark and
| | - Jacek Mokrosinski
- From the Laboratory for Molecular Pharmacology, Department of Neuroscience and Pharmacology, The Panum Institute, Novo Nordisk Foundation Center for Basic Metabolic Research, and
| | - Nicholas D Holliday
- the Cell Signaling Research Group, School of Life Sciences, University of Nottingham, Queen's Medical Centre, Nottingham NG7 2UH, United Kingdom
| | - Thue W Schwartz
- From the Laboratory for Molecular Pharmacology, Department of Neuroscience and Pharmacology, The Panum Institute, Novo Nordisk Foundation Center for Basic Metabolic Research, and
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25
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Activation of Phosphatidylinositol-Linked Dopamine Receptors Induces a Facilitation of Glutamate-Mediated Synaptic Transmission in the Lateral Entorhinal Cortex. PLoS One 2015; 10:e0131948. [PMID: 26133167 PMCID: PMC4489908 DOI: 10.1371/journal.pone.0131948] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/18/2015] [Accepted: 06/08/2015] [Indexed: 11/19/2022] Open
Abstract
The lateral entorhinal cortex receives strong inputs from midbrain dopamine neurons that can modulate its sensory and mnemonic function. We have previously demonstrated that 1 µM dopamine facilitates synaptic transmission in layer II entorhinal cortex cells via activation of D1-like receptors, increased cAMP-PKA activity, and a resulting enhancement of AMPA-receptor mediated currents. The present study assessed the contribution of phosphatidylinositol (PI)-linked D1 receptors to the dopaminergic facilitation of transmission in layer II of the rat entorhinal cortex, and the involvement of phospholipase C activity and release of calcium from internal stores. Whole-cell patch-clamp recordings of glutamate-mediated evoked excitatory postsynaptic currents were obtained from pyramidal and fan cells. Activation of D1-like receptors using SKF38393, SKF83959, or 1 µM dopamine induced a reversible facilitation of EPSCs which was abolished by loading cells with either the phospholipase C inhibitor U-73122 or the Ca2+ chelator BAPTA. Neither the L-type voltage-gated Ca2+ channel blocker nifedipine, nor the L/N-type channel blocker cilnidipine, blocked the facilitation of synaptic currents. However, the facilitation was blocked by blocking Ca2+ release from internal stores via inositol 1,4,5-trisphosphate (InsP3) receptors or ryanodine receptors. Follow-up studies demonstrated that inhibiting CaMKII activity with KN-93 failed to block the facilitation, but that application of the protein kinase C inhibitor PKC(19-36) completely blocked the dopamine-induced facilitation. Overall, in addition to our previous report indicating a role for the cAMP-PKA pathway in dopamine-induced facilitation of synaptic transmission, we demonstrate here that the dopaminergic facilitation of synaptic responses in layer II entorhinal neurons also relies on a signaling cascade dependent on PI-linked D1 receptors, PLC, release of Ca2+ from internal stores, and PKC activation which is likely dependent upon both DAG and enhanced intracellular Ca2+. These signaling pathways may collaborate to enhance sensory and mnemonic function in the entorhinal cortex during tonic release of dopamine.
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26
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Luttrell LM, Maudsley S, Bohn LM. Fulfilling the Promise of "Biased" G Protein-Coupled Receptor Agonism. Mol Pharmacol 2015; 88:579-88. [PMID: 26134495 DOI: 10.1124/mol.115.099630] [Citation(s) in RCA: 148] [Impact Index Per Article: 16.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/22/2015] [Accepted: 07/01/2015] [Indexed: 12/13/2022] Open
Abstract
The fact that over 30% of current pharmaceuticals target heptahelical G protein-coupled receptors (GPCRs) attests to their tractability as drug targets. Although GPCR drug development has traditionally focused on conventional agonists and antagonists, the growing appreciation that GPCRs mediate physiologically relevant effects via both G protein and non-G protein effectors has prompted the search for ligands that can "bias" downstream signaling in favor of one or the other process. Biased ligands are novel entities with distinct signaling profiles dictated by ligand structure, and the potential prospect of biased ligands as better drugs has been pleonastically proclaimed. Indeed, preclinical proof-of-concept studies have demonstrated that both G protein and arrestin pathway-selective ligands can promote beneficial effects in vivo while simultaneously antagonizing deleterious ones. But along with opportunity comes added complexity and new challenges for drug discovery. If ligands can be biased, then ligand classification becomes assay dependent, and more nuanced screening approaches are needed to capture ligand efficacy across several dimensions of signaling. Moreover, because the signaling repertoire of biased ligands differs from that of the native agonist, unpredicted responses may arise in vivo as these unbalanced signals propagate. For any given GPCR target, establishing a framework relating in vitro efficacy to in vivo biologic response is crucial to biased drug discovery. This review discusses approaches to describing ligand efficacy in vitro, translating ligand bias into biologic response, and developing a systems-level understanding of biased agonism in vivo, with the overall goal of overcoming current barriers to developing biased GPCR therapeutics.
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Affiliation(s)
- Louis M Luttrell
- Departments of Medicine and Biochemistry & Molecular Biology, Medical University of South Carolina, Charleston, South Carolina (L.M.L.); Ralph H. Johnson Veterans Affairs Medical Center, Charleston, South Carolina (L.M.L.); Translational Neurobiology Group, VIB Department of Molecular Genetics, Laboratory of Neurogenetics-Institute Born-Bunge, University of Antwerp, Belgium (S.M.); and Department of Molecular Therapeutics and Department of Neuroscience, The Scripps Research Institute, Jupiter, Florida (L.M.B.)
| | - Stuart Maudsley
- Departments of Medicine and Biochemistry & Molecular Biology, Medical University of South Carolina, Charleston, South Carolina (L.M.L.); Ralph H. Johnson Veterans Affairs Medical Center, Charleston, South Carolina (L.M.L.); Translational Neurobiology Group, VIB Department of Molecular Genetics, Laboratory of Neurogenetics-Institute Born-Bunge, University of Antwerp, Belgium (S.M.); and Department of Molecular Therapeutics and Department of Neuroscience, The Scripps Research Institute, Jupiter, Florida (L.M.B.)
| | - Laura M Bohn
- Departments of Medicine and Biochemistry & Molecular Biology, Medical University of South Carolina, Charleston, South Carolina (L.M.L.); Ralph H. Johnson Veterans Affairs Medical Center, Charleston, South Carolina (L.M.L.); Translational Neurobiology Group, VIB Department of Molecular Genetics, Laboratory of Neurogenetics-Institute Born-Bunge, University of Antwerp, Belgium (S.M.); and Department of Molecular Therapeutics and Department of Neuroscience, The Scripps Research Institute, Jupiter, Florida (L.M.B.)
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Walther C, Ferguson SSG. Minireview: Role of intracellular scaffolding proteins in the regulation of endocrine G protein-coupled receptor signaling. Mol Endocrinol 2015; 29:814-30. [PMID: 25942107 DOI: 10.1210/me.2015-1091] [Citation(s) in RCA: 29] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/28/2022] Open
Abstract
The majority of hormones stimulates and mediates their signal transduction via G protein-coupled receptors (GPCRs). The signal is transmitted into the cell due to the association of the GPCRs with heterotrimeric G proteins, which in turn activates an extensive array of signaling pathways to regulate cell physiology. However, GPCRs also function as scaffolds for the recruitment of a variety of cytoplasmic protein-interacting proteins that bind to both the intracellular face and protein interaction motifs encoded by GPCRs. The structural scaffolding of these proteins allows GPCRs to recruit large functional complexes that serve to modulate both G protein-dependent and -independent cellular signaling pathways and modulate GPCR intracellular trafficking. This review focuses on GPCR interacting PSD95-disc large-zona occludens domain containing scaffolds in the regulation of endocrine receptor signaling as well as their potential role as therapeutic targets for the treatment of endocrinopathies.
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Affiliation(s)
- Cornelia Walther
- J. Allyn Taylor Centre for Cell Biology (C.W., S.S.G.F.), Robarts Research Institute, and Department of Physiology and Pharmacology (S.S.G.F.), University of Western Ontario, London, Ontario, Canada N6A 5K8
| | - Stephen S G Ferguson
- J. Allyn Taylor Centre for Cell Biology (C.W., S.S.G.F.), Robarts Research Institute, and Department of Physiology and Pharmacology (S.S.G.F.), University of Western Ontario, London, Ontario, Canada N6A 5K8
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Bohn LM, Zhou L, Ho JH. Approaches to Assess Functional Selectivity in GPCRs: Evaluating G Protein Signaling in an Endogenous Environment. Methods Mol Biol 2015; 1335:177-189. [PMID: 26260601 PMCID: PMC4804702 DOI: 10.1007/978-1-4939-2914-6_12] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 06/04/2023]
Abstract
Ligand-directed signaling, biased agonism, and functional selectivity are terms that describe the propensity of a ligand to drive signaling toward one GPCR pathway over another. Most of the early examples demonstrated to date examine the divergence between GPCR signaling to G protein coupling and βarrestin2 recruitment. As biased agonists begin to become available based on cell-based screening criteria, a need arises to determine if G protein signaling biases will be maintained in the endogenous setting, wherein receptors are functioning to control relevant biological responses. This report presents our method and offers tips for evaluating G protein signaling in endogenous tissues. Predominately, brain tissues are discussed here; optimization points that can be applied to any tissues are highlighted.
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Affiliation(s)
- Laura M Bohn
- Departments of Molecular Therapeutics and Neuroscience, The Scripps Research Institute, 130 Scripps Way #2A2, Jupiter, FL, 33458, USA,
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Association of dopamine receptor D1 (DRD1) polymorphisms with risperidone treatment response in Chinese schizophrenia patients. Neurosci Lett 2015; 584:178-83. [DOI: 10.1016/j.neulet.2014.08.041] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/22/2014] [Revised: 08/10/2014] [Accepted: 08/25/2014] [Indexed: 11/23/2022]
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Odagaki Y, Kinoshita M, Toyoshima R. Functional activation of Gαq via serotonin2A (5-HT2A) and muscarinic acetylcholine M1 receptors assessed by guanosine-5׳-O-(3-[35S]thio)triphosphate ([35S]GTPγS) binding/immunoprecipitation in rat brain membranes. Eur J Pharmacol 2014; 726:109-15. [PMID: 24485888 DOI: 10.1016/j.ejphar.2013.12.040] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/21/2013] [Revised: 12/10/2013] [Accepted: 12/30/2013] [Indexed: 11/29/2022]
Abstract
Functional coupling between serotonin2A (5-HT2A) receptors and Gαq proteins in native brain membranes has been sparsely reported thus far. In the present study, the guanosine-5׳-O-(3-[35S]thio)triphosphate ([35S]GTPγS) binding assay combined with immunoprecipitation using magnetic beads (Dynabeads Protein A) coated with anti-Gαq antibody was developed. Under experimental conditions optimised for assay constituents (GDP, MgCl2, and NaCl), for contents of membrane protein, anti-Gαq antibody, and Dynabeads Protein A, and for the incubation period, 5-HT stimulated specific [35S]GTPγS binding to Gαq in rat cerebral cortical membranes in a concentration-dependent and saturable manner, with a signal/noise ratio that was sufficiently high for further detailed pharmacological characterisation. This characterisation revealed an involvement of 5-HT2A receptors. Activation of Gαq proteins was also detectable by the addition of carbachol via muscarinic acetylcholine M1 receptors, (-)-epinephrine, and dopamine, but not by L-glutamate or (±)-baclofen. When 5-HT2A receptors and M1 receptors were stimulated simultaneously, there were non-additive effects, indicating that the two receptors were coupled to the same components of Gαq proteins in the rat cerebral cortex. This method will serve as an efficacious strategy for neurobiological investigations aimed at elucidating the physiological and pathological implications of signal transduction systems mediated via Gαq proteins coupled with 5-HT2A receptors and muscarinic acetylcholine M1 receptors.
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Krawczyk M, deBacker J, Mason X, Jones AA, Dumont EC. Dopamine decreases NMDA currents in the oval bed nucleus of the stria terminalis of cocaine self-administering rats. Prog Neuropsychopharmacol Biol Psychiatry 2014; 51:83-8. [PMID: 24472317 PMCID: PMC4011798 DOI: 10.1016/j.pnpbp.2014.01.011] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 12/04/2013] [Revised: 01/17/2014] [Accepted: 01/19/2014] [Indexed: 11/17/2022]
Abstract
Dopamine (DA) and N-methyl-D-aspartate receptors (NMDARs) contribute in the neural processes underlying drug-driven behaviors. DA is a potent modulator of NMDAR, but few studies have investigated the functional interaction between DA and NMDAR in the context of substance abuse. We combined the rat model of cocaine self-administration with brain slice electrophysiology to study DA modulation of NMDA currents in the oval bed nucleus of the stria terminalis (ovBNST), a dense DA terminal field involved in maintenance of cocaine self-administration amongst other drug related behaviors. Long-Evans rats self-administered intravenous cocaine (0.75 mg/kg/injection) on a progressive ratio (PR) schedule of reinforcement for 15 days and whole-cell patch-clamp recordings were done on the 16th day. DA reduced NMDA currents in brain-slices from cocaine self-administering rats, but not in those of drug-naïve and sucrose self-administering, or when cocaine exposure was passive (yoked), revealing a mechanism unique to voluntary cocaine intake. DA reduced NMDA currents by activating G-protein-coupled D1- and D2-like receptors that converged on phospholipase C and protein phosphatases. Accordingly, our study reveals a mechanism that may contribute to dysfunctional synaptic plasticity associated with drug-driven behaviors during acute withdrawal.
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Affiliation(s)
- Michal Krawczyk
- Department of Biomedical and Molecular Sciences, Center for Neuroscience Studies, Queen's University, 99 University Avenue, Kingston, Ontario K7L 3N6, Canada
| | - Julian deBacker
- Department of Biomedical and Molecular Sciences, Center for Neuroscience Studies, Queen's University, 99 University Avenue, Kingston, Ontario K7L 3N6, Canada
| | - Xenos Mason
- Department of Biomedical and Molecular Sciences, Center for Neuroscience Studies, Queen's University, 99 University Avenue, Kingston, Ontario K7L 3N6, Canada
| | - Andrea A Jones
- Department of Biomedical and Molecular Sciences, Center for Neuroscience Studies, Queen's University, 99 University Avenue, Kingston, Ontario K7L 3N6, Canada
| | - Eric C Dumont
- Department of Biomedical and Molecular Sciences, Center for Neuroscience Studies, Queen's University, 99 University Avenue, Kingston, Ontario K7L 3N6, Canada.
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Biased ligands: pathway validation for novel GPCR therapeutics. Curr Opin Pharmacol 2014; 16:108-15. [PMID: 24834870 DOI: 10.1016/j.coph.2014.04.002] [Citation(s) in RCA: 22] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/17/2014] [Revised: 04/15/2014] [Accepted: 04/18/2014] [Indexed: 01/14/2023]
Abstract
G protein-coupled receptors (GPCRs), in recent years, have been shown to signal via multiple distinct pathways. Furthermore, biased ligands for some receptors can differentially stimulate or inhibit these pathways versus unbiased endogenous ligands or drugs. Biased ligands can be used to gain a deeper understanding of the molecular targets and cellular responses associated with a GPCR, and may be developed into therapeutics with improved efficacy, safety and/or tolerability. Here we review examples and approaches to pathway validation that establish the relevance and therapeutic potential of distinct pathways that can be selectively activated or blocked by biased ligands.
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Gildea JJ, Shah IT, Van Sciver RE, Israel JA, Enzensperger C, McGrath HE, Jose PA, Felder RA. The cooperative roles of the dopamine receptors, D1R and D5R, on the regulation of renal sodium transport. Kidney Int 2014; 86:118-26. [PMID: 24552847 PMCID: PMC4077925 DOI: 10.1038/ki.2014.5] [Citation(s) in RCA: 24] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/25/2013] [Revised: 11/27/2013] [Accepted: 12/12/2013] [Indexed: 02/07/2023]
Abstract
Determining the individual roles of the two dopamine D1-like receptors (D1R and D5R) on sodium transport in the human renal proximal tubule has been complicated by their structural and functional similarity. Here we used a novel D5R-selective antagonist (LE-PM436) and D1R or D5R-specific gene silencing to determine second messenger coupling pathways and heterologous receptor interaction between the two receptors. D1R and D5R co-localized in renal proximal tubule cells and physically interact, as determined by co-immunoprecipitation and FRET microscopy. Stimulation of renal proximal tubule cells with fenoldopam (D1R/D5R agonist) led to both adenylyl cyclase and phospholipase C (PLC) activation using real-time FRET biosensors ICUE3 and CYPHR, respectively. Fenoldopam increased cAMP accumulation and PLC activity and inhibited both NHE3 and NaKATPase activities. LE-PM436 and D5R siRNA blocked the fenoldopam-stimulated PLC pathway but not cAMP accumulation, while D1R siRNA blocked both fenoldopam-stimulated cAMP accumulation and PLC signaling. Either D1R or D5R siRNA, or LE-PM436 blocked the fenoldopam dependent inhibition of sodium transport. Further studies using the cAMP-selective D1R/D5R agonist SKF83822 and PLC-selective D1R/D5R agonist SKF83959 confirmed the cooperative influence of the two pathways on sodium transport. Thus, D1R and D5R interact in the inhibition of NHE3 and NaKATPase activity, the D1R primarily by cAMP, while the D1R/D5R heteromer modulates the D1R effect through a PLC pathway.
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Affiliation(s)
- John J Gildea
- The University of Virginia Health System, Department of Pathology, Charlottesville, Virginia, USA
| | - Ishan T Shah
- The University of Virginia Health System, Department of Pathology, Charlottesville, Virginia, USA
| | - Robert E Van Sciver
- The University of Virginia Health System, Department of Pathology, Charlottesville, Virginia, USA
| | - Jonathan A Israel
- The University of Virginia Health System, Department of Pathology, Charlottesville, Virginia, USA
| | - Christoph Enzensperger
- Institut für Pharmazie, Lehrstuhl für Pharmazeutische/Medizinische Chemie, Friedrich-Schiller-Universität Jena, Jena, Germany
| | - Helen E McGrath
- The University of Virginia Health System, Department of Pathology, Charlottesville, Virginia, USA
| | - Pedro A Jose
- University of Maryland School of Medicine, Departments of Medicine and Physiology, Baltimore, Maryland, USA
| | - Robin A Felder
- The University of Virginia Health System, Department of Pathology, Charlottesville, Virginia, USA
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Luttrell LM. Minireview: More than just a hammer: ligand "bias" and pharmaceutical discovery. Mol Endocrinol 2014; 28:281-94. [PMID: 24433041 DOI: 10.1210/me.2013-1314] [Citation(s) in RCA: 89] [Impact Index Per Article: 8.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/06/2023] Open
Abstract
Conventional orthosteric drug development programs targeting G protein-coupled receptors (GPCRs) have focused on the concepts of agonism and antagonism, in which receptor structure determines the nature of the downstream signal and ligand efficacy determines its intensity. Over the past decade, the emerging paradigms of "pluridimensional efficacy" and "functional selectivity" have revealed that GPCR signaling is not monolithic, and that ligand structure can "bias" signal output by stabilizing active receptor states in different proportions than the native ligand. Biased ligands are novel pharmacologic entities that possess the unique ability to qualitatively change GPCR signaling, in effect creating "new receptors" with distinct efficacy profiles driven by ligand structure. The promise of biased agonism lies in this ability to engender "mixed" effects not attainable using conventional agonists or antagonists, promoting therapeutically beneficial signals while antagonizing deleterious ones. Indeed, arrestin pathway-selective agonists for the type 1 parathyroid hormone and angiotensin AT1 receptors, and G protein pathway-selective agonists for the GPR109A nicotinic acid and μ-opioid receptors, have demonstrated unique, and potentially therapeutic, efficacy in cell-based assays and preclinical animal models. Conversely, activating GPCRs in "unnatural" ways may lead to downstream biological consequences that cannot be predicted from prior knowledge of the actions of the native ligand, especially in the case of ligands that selectively activate as-yet poorly characterized G protein-independent signaling networks mediated via arrestins. Although much needs to be done to realize the clinical potential of functional selectivity, biased GPCR ligands nonetheless appear to be important new additions to the pharmacologic toolbox.
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Affiliation(s)
- Louis M Luttrell
- Department of Medicine and Department of Biochemistry & Molecular Biology, Medical University of South Carolina, Charleston, South Carolina 29425; and Ralph H. Johnson Veterans Affairs Medical Center, Charleston, South Carolina 29401
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Vicente-Sánchez A, Sánchez-Blázquez P, Rodríguez-Muñoz M, Garzón J. HINT1 protein cooperates with cannabinoid 1 receptor to negatively regulate glutamate NMDA receptor activity. Mol Brain 2013; 6:42. [PMID: 24093505 PMCID: PMC3851374 DOI: 10.1186/1756-6606-6-42] [Citation(s) in RCA: 39] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/22/2013] [Accepted: 09/19/2013] [Indexed: 01/02/2023] Open
Abstract
Background G protein-coupled receptors (GPCRs) are the targets of a large number of drugs currently in therapeutic use. Likewise, the glutamate ionotropic N-methyl-D-aspartate receptor (NMDAR) has been implicated in certain neurological disorders, such as neurodegeration, neuropathic pain and mood disorders, as well as psychosis and schizophrenia. Thus, there is now an important need to characterize the interactions between GPCRs and NMDARs. Indeed, these interactions can produce distinct effects, and whereas the activation of Mu-opioid receptor (MOR) increases the calcium fluxes associated to NMDARs, that of type 1 cannabinoid receptor (CNR1) antagonizes their permeation. Notably, a series of proteins interact with these receptors affecting their responses and interactions, and then emerge as novel therapeutic targets for the aforementioned pathologies. Results We found that in the presence of GPCRs, the HINT1 protein influences the activity of NMDARs, whereby NMDAR activation was enhanced in CNR1+/+/HINT1-/- cortical neurons and the cannabinoid agonist WIN55,212-2 provided these cells with no protection against a NMDA insult. NMDAR activity was normalized in these cells by the lentiviral expression of HINT1, which also restored the neuroprotection mediated by cannabinoids. NMDAR activity was also enhanced in CNR1-/-/HINT1+/+ neurons, although this activity was dampened by the expression of GPCRs like the MOR, CNR1 or serotonin 1A (5HT1AR). Conclusions The HINT1 protein plays an essential role in the GPCR-NMDAR connection. In the absence of receptor activation, GPCRs collaborate with HINT1 proteins to negatively control NMDAR activity. When activated, most GPCRs release the control of HINT1 and NMDAR responsiveness is enhanced. However, cannabinoids that act through CNR1 maintain the negative control of HINT1 on NMDAR function and their protection against glutamate excitotoxic insult persists.
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Gangarossa G, Valjent E. Regulation of the ERK pathway in the dentate gyrus by in vivo dopamine D1 receptor stimulation requires glutamatergic transmission. Neuropharmacology 2012; 63:1107-17. [PMID: 22796106 DOI: 10.1016/j.neuropharm.2012.06.062] [Citation(s) in RCA: 24] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/31/2012] [Revised: 06/22/2012] [Accepted: 06/29/2012] [Indexed: 11/18/2022]
Abstract
Acute systemic administration of the dopamine D1/D5 receptors (D1Rs) agonist, SKF81297, activates the extracellular signal-regulated protein kinases (ERK) pathway selectively in the granule cells of the dentate gyrus. In this study, we examined the mechanisms involved in this regulation and investigated the molecular components that could promote ERK-dependent transcription and translation. SKF81297 induced phosphorylation of ERK and histone H3 required intact glutamatergic transmission. Blockade of glutamate release achieved by the mGluR2/3 agonist, LY354740 or the selective adenosine A1R agonist, CCPA as well as neurotoxic lesions of lateral entorhinal cortex reduced the ability of SKF81297 to induce ERK activation in the dentate gyrus. This activation required the combined stimulation of NR2B-containing NMDARs, mGluR1 and mGluR5. SKF81297 evoked phosphorylation of the ribosomal protein S6 (rpS6) selectively at the Ser235/236 site while the Ser240/244 site remains unchanged. The SKF81297 induced increased phosphorylation of rpS6 was dependent on PKC and ERK/p90RSK activation. Surprisingly, administration of D1Rs agonist suppressed mTORC1/p70S6K pathway suggesting an mTOR-independent regulation of rpS6 phosphorylation. Taken together, our results show that intact glutamatergic transmission plays a major role in the regulation of ERK-dependent phosphorylation of histone H3 and rpS6 observed in the mouse dentate gyrus after systemic administration of SKF81297.
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Mizuno K, Kurokawa K, Ohkuma S. Dopamine D1 receptors regulate type 1 inositol 1,4,5-trisphosphate receptor expression via both AP-1- and NFATc4-mediated transcriptional processes. J Neurochem 2012; 122:702-13. [PMID: 22686291 DOI: 10.1111/j.1471-4159.2012.07827.x] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
Although our recent report demonstrates the essential involvement of up-regulation of a regulator of intracellular Ca(2+) concentration, type 1 inositol 1,4,5-trisphosphate receptors (IP(3) Rs-1), mediated via dopamine D1-like receptor (D1DR) stimulation in the cocaine-induced psychological dependence, the exact mechanisms of regulation of IP(3) R-1 expression by D1DRs have not yet been clarified. This study attempted to clarify these mechanisms using mouse cerebral cortical neurons. An agonist for phosphatidylinositide-linked D1DRs, SKF83959, induced dose- and time-dependently IP(3) R-1 protein up-regulation following its mRNA increase without cAMP production. U73122 (a phospholipase C inhibitor), BAPTA-AM (an intracellular calcium chelating reagent), W7 (a calmodulin inhibitor), KN-93 (a calmodulin-dependent protein kinases inhibitor), and FK506 (a calcineurin inhibitor), significantly inhibited the SKF83959-induced IP(3) R-1 up-regulation. Furthermore, immunohistochemical examinations showed that SKF83959 increased expression of both cFos and cJun in nucleus as well as enhanced translocation of both calcineurin and NFATc4 complex to nucleus from cytoplasm. In addition, SKF83959 directly recruited binding of both AP-1 and NFATc4 to IP(3) R-1 promoter region. These results indicate that D1DR activation induces IP(3) R-1 up-regulation via increased translocation of AP-1 as well as NFATc4 in Gαq protein-coupled calcium signaling transduction pathway.
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Affiliation(s)
- Koji Mizuno
- Department of Pharmacology, Kawasaki Medical School, Kurashiki, Japan
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Frederick AL, Saborido TP, Stanwood GD. Neurobehavioral phenotyping of G(αq) knockout mice reveals impairments in motor functions and spatial working memory without changes in anxiety or behavioral despair. Front Behav Neurosci 2012; 6:29. [PMID: 22723772 PMCID: PMC3377978 DOI: 10.3389/fnbeh.2012.00029] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/09/2012] [Accepted: 05/29/2012] [Indexed: 11/18/2022] Open
Abstract
Many neurotransmitters, hormones, and sensory stimuli elicit their cellular responses through the targeted activation of receptors coupled to the Gαq family of heterotrimeric G proteins. Nevertheless, we still understand little about the consequences of loss of this signaling activity on brain function. We therefore examined the effects of genetic inactivation of Gnaq, the gene that encode for Gαq, on responsiveness in a battery of behavioral tests in order to assess the contribution of Gαq signaling capacity in the brain circuits mediating expression of affective behaviors (anxiety and behavioral despair), spatial working memory, and locomotor output (coordination, strength, spontaneous activity, and drug-induced responses). First, we replicated and extended findings showing clear motor deficits in Gαq knockout mice as assessed on an accelerating rotarod and the inverted screen test. We then assessed the contribution of the basal ganglia motor loops to these impairments, using open field testing and analysis of drug-induced locomotor responses to the psychostimulant cocaine, the benzazepine D1 receptor agonists SKF83822 and SKF83959, and the NMDA receptor antagonist MK-801. We observed significant increases in drug-induced locomotor activity in Gαq knockout mice from the dopaminergic agonists but not MK-801, indicating that basal ganglia locomotor circuitry is largely intact in the absence of Gαq. Additionally, we observed normal phenotypes in both the elevated zero maze and the forced swim test indicating that anxiety and depression-related circuitry appears to be largely intact after loss of Gnaq expression. Lastly, use of the Y-maze revealed spatial memory deficits in Gαq knockout mice, indicating that receptors signaling through Gαq are necessary in these circuits for proficiency in this task.
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Affiliation(s)
- Aliya L Frederick
- Neuroscience Graduate Program, Vanderbilt University School of Medicine, Nashville TN, USA
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Wu J, Xiao H, Sun H, Zou L, Zhu LQ. Role of dopamine receptors in ADHD: a systematic meta-analysis. Mol Neurobiol 2012; 45:605-20. [PMID: 22610946 DOI: 10.1007/s12035-012-8278-5] [Citation(s) in RCA: 171] [Impact Index Per Article: 14.3] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/06/2012] [Accepted: 05/07/2012] [Indexed: 01/11/2023]
Abstract
The dopaminergic system plays a pivotal role in the central nervous system via its five diverse receptors (D1-D5). Dysfunction of dopaminergic system is implicated in many neuropsychological diseases, including attention deficit hyperactivity disorder (ADHD), a common mental disorder that prevalent in childhood. Understanding the relationship of five different dopamine (DA) receptors with ADHD will help us to elucidate different roles of these receptors and to develop therapeutic approaches of ADHD. This review summarized the ongoing research of DA receptor genes in ADHD pathogenesis and gathered the past published data with meta-analysis and revealed the high risk of DRD5, DRD2, and DRD4 polymorphisms in ADHD.
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Affiliation(s)
- Jing Wu
- Department of Epidemiology and Biostatistics and Ministry of Education Key Lab of Environment and Health, School of Public Health, Tongji Medical College, Huazhong University of Science and Technology, Wuhan, China
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Nishi A, Kuroiwa M, Shuto T. Mechanisms for the modulation of dopamine d(1) receptor signaling in striatal neurons. Front Neuroanat 2011; 5:43. [PMID: 21811441 PMCID: PMC3140648 DOI: 10.3389/fnana.2011.00043] [Citation(s) in RCA: 102] [Impact Index Per Article: 7.8] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/14/2011] [Accepted: 07/07/2011] [Indexed: 01/11/2023] Open
Abstract
In the striatum, dopamine D(1) receptors are preferentially expressed in striatonigral neurons, and increase the neuronal excitability, leading to the increase in GABAergic inhibitory output to substantia nigra pars reticulata. Such roles of D(1) receptors are important for the control of motor functions. In addition, the roles of D(1) receptors are implicated in reward, cognition, and drug addiction. Therefore, elucidation of mechanisms for the regulation of dopamine D(1) receptor signaling is required to identify therapeutic targets for Parkinson's disease and drug addiction. D(1) receptors are coupled to G(s/olf)/adenylyl cyclase/PKA signaling, leading to the phosphorylation of PKA substrates including DARPP-32. Phosphorylated form of DARPP-32 at Thr34 has been shown to inhibit protein phosphatase-1, and thereby controls the phosphorylation states and activity of many downstream physiological effectors. Roles of DARPP-32 and its phosphorylation at Thr34 and other sites in D(1) receptor signaling are extensively studied. In addition, functional roles of the non-canonical D(1) receptor signaling cascades that coupled to G(q)/phospholipase C or Src family kinase become evident. We have recently shown that phosphodiesterases (PDEs), especially PDE10A, play a pivotal role in regulating the tone of D(1) receptor signaling relatively to that of D(2) receptor signaling. We review the current understanding of molecular mechanisms for the modulation of D(1) receptor signaling in the striatum.
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Affiliation(s)
- Akinori Nishi
- Department of Pharmacology, Kurume University School of Medicine Kurume, Fukuoka, Japan
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Abstract
Dopamine is an important regulator of systemic blood pressure via multiple mechanisms. It affects fluid and electrolyte balance by its actions on renal hemodynamics and epithelial ion and water transport and by regulation of hormones and humoral agents. The kidney synthesizes dopamine from circulating or filtered L-DOPA independently from innervation. The major determinants of the renal tubular synthesis/release of dopamine are probably sodium intake and intracellular sodium. Dopamine exerts its actions via two families of cell surface receptors, D1-like receptors comprising D1R and D5R, and D2-like receptors comprising D2R, D3R, and D4R, and by interactions with other G protein-coupled receptors. D1-like receptors are linked to vasodilation, while the effect of D2-like receptors on the vasculature is variable and probably dependent upon the state of nerve activity. Dopamine secreted into the tubular lumen acts mainly via D1-like receptors in an autocrine/paracrine manner to regulate ion transport in the proximal and distal nephron. These effects are mediated mainly by tubular mechanisms and augmented by hemodynamic mechanisms. The natriuretic effect of D1-like receptors is caused by inhibition of ion transport in the apical and basolateral membranes. D2-like receptors participate in the inhibition of ion transport during conditions of euvolemia and moderate volume expansion. Dopamine also controls ion transport and blood pressure by regulating the production of reactive oxygen species and the inflammatory response. Essential hypertension is associated with abnormalities in dopamine production, receptor number, and/or posttranslational modification.
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Affiliation(s)
- Ines Armando
- Children’s National Medical Center—Center for Molecular Physiology Research, Washington, District of Columbia
| | - Van Anthony M. Villar
- Children’s National Medical Center—Center for Molecular Physiology Research, Washington, District of Columbia
| | - Pedro A. Jose
- Children’s National Medical Center—Center for Molecular Physiology Research, Washington, District of Columbia
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Coexpressed D1- and D2-like dopamine receptors antagonistically modulate acetylcholine release in Caenorhabditis elegans. Genetics 2011; 188:579-90. [PMID: 21515580 DOI: 10.1534/genetics.111.128512] [Citation(s) in RCA: 44] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
Abstract
Dopamine acts through two classes of G protein-coupled receptor (D1-like and D2-like) to modulate neuron activity in the brain. While subtypes of D1- and D2-like receptors are coexpressed in many neurons of the mammalian brain, it is unclear how signaling by these coexpressed receptors interacts to modulate the activity of the neuron in which they are expressed. D1- and D2-like dopamine receptors are also coexpressed in the cholinergic ventral-cord motor neurons of Caenorhabditis elegans. To begin to understand how coexpressed dopamine receptors interact to modulate neuron activity, we performed a genetic screen in C. elegans and isolated mutants defective in dopamine response. These mutants were also defective in behaviors mediated by endogenous dopamine signaling, including basal slowing and swimming-induced paralysis. We used transgene rescue experiments to show that defects in these dopamine-specific behaviors were caused by abnormal signaling in the cholinergic motor neurons. To investigate the interaction between the D1- and D2-like receptors specifically in these cholinergic motor neurons, we measured the sensitivity of dopamine-signaling mutants and transgenic animals to the acetylcholinesterase inhibitor aldicarb. We found that D2 signaling inhibited acetylcholine release from the cholinergic motor neurons while D1 signaling stimulated release from these same cells. Thus, coexpressed D1- and D2-like dopamine receptors act antagonistically in vivo to modulate acetylcholine release from the cholinergic motor neurons of C. elegans.
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Gesty-Palmer D, Luttrell LM. Refining efficacy: exploiting functional selectivity for drug discovery. ADVANCES IN PHARMACOLOGY (SAN DIEGO, CALIF.) 2011; 62:79-107. [PMID: 21907907 DOI: 10.1016/b978-0-12-385952-5.00009-9] [Citation(s) in RCA: 25] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/14/2022]
Abstract
Early models of G protein-coupled receptor (GPCR) activation envisioned the receptor in equilibrium between unique "off" and "on" states, wherein ligand binding affected signaling by increasing or decreasing the fraction of receptors in the active conformation. It is now apparent that GPCRs spontaneously sample multiple conformations, any number of which may couple to one or more downstream effectors. Such "multistate" models imply that the receptor-ligand complex, not the receptor alone, defines which active receptor conformations predominate. "Functional selectivity" refers to the ability of a ligand to activate only a subset of its receptor's signaling repertoire. There are now numerous examples of ligands that "bias" receptor coupling between different G protein pools and non-G protein effectors such as arrestins. The type 1 parathyroid hormone receptor (PTH(1)R) is a particularly informative example, not only because of the range of biased effects that have been produced, but also because the actions of many of these ligands have been characterized in vivo. Biased PTH(1)R ligands can selectively couple the PTH(1)R to G(s) or G(q/11) pathways, with or without activating arrestin-dependent receptor desensitization and signaling. These reagents have provided insight into the contribution of different signaling pathways to PTH action in vivo and suggest it may be possible to exploit ligand bias to uncouple the anabolic effects of PTH(1)R from its catabolic and calcitropic effects. Whereas conventional agonists and antagonists only modulate the quantity of efficacy, functionally selective ligands qualitatively change GPCR signaling, offering the prospect of drugs with improved therapeutic efficacy or reduced side effects.
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Affiliation(s)
- Diane Gesty-Palmer
- Department of Medicine, Duke University Medical Center, Durham, North Carolina, USA
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Choi IS, Cho JH, Jang IS. Dopamine inhibition of glycine release in the rat trigeminal nucleus pars caudalis: possible involvement of trace amine receptors. J Neurochem 2010; 114:1639-50. [DOI: 10.1111/j.1471-4159.2010.06870.x] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
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Thiel KJ, Wenzel JM, Pentkowski NS, Hobbs RJ, Alleweireldt AT, Neisewander JL. Stimulation of dopamine D2/D3 but not D1 receptors in the central amygdala decreases cocaine-seeking behavior. Behav Brain Res 2010; 214:386-94. [PMID: 20600343 DOI: 10.1016/j.bbr.2010.06.021] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/06/2009] [Revised: 05/24/2010] [Accepted: 06/09/2010] [Indexed: 10/19/2022]
Abstract
Alterations in dopamine output within the various subnuclei of the amygdala have previously been implicated in cocaine reinforcement, as well as cocaine-seeking behavior. To elucidate the potential for increased stimulation of D1- and D2-like receptors (D1Rs and D2Rs, respectively) specifically in the central nucleus of the amygdala (CeA) to modulate cue- and cocaine-elicited reinstatement of cocaine-seeking behavior, we infused either the D1R agonist, SKF-38393 (0-4.0 microg/side) or the D2R agonist, 7-OH-DPAT (0-4.0 microg/side) into the CeA immediately prior to tests for cue and cocaine-primed reinstatement. We also examined the effects of 7-OH-DPAT on cocaine self-administration as a positive behavioral control. 7-OH-DPAT decreased cue-and cocaine-primed reinstatement, and reduced the number of cocaine infusions obtained during self-administration; SKF-38393 produced no discernable effects. The results suggest that enhanced stimulation of D2Rs, but not D1Rs, in the CeA is sufficient to inhibit expression of the incentive motivational effects of cocaine priming and cocaine-paired cues. Together with previous findings that D1R blockade attenuates reinstatement of cocaine-seeking behavior, the results suggest that D1R stimulation may be necessary, but not sufficient, to modulate the incentive motivational effects of cues and cocaine priming.
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Affiliation(s)
- Kenneth J Thiel
- Department of Psychology, Arizona State University, P.O. Box 871104, Tempe, AZ 85287-1104, United States
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Undieh AS. Pharmacology of signaling induced by dopamine D(1)-like receptor activation. Pharmacol Ther 2010; 128:37-60. [PMID: 20547182 DOI: 10.1016/j.pharmthera.2010.05.003] [Citation(s) in RCA: 88] [Impact Index Per Article: 6.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/19/2010] [Accepted: 05/19/2010] [Indexed: 12/30/2022]
Abstract
Dopamine D(1)-like receptors consisting of D(1) and D(5) subtypes are intimately implicated in dopaminergic regulation of fundamental neurophysiologic processes such as mood, motivation, cognitive function, and motor activity. Upon stimulation, D(1)-like receptors initiate signal transduction cascades that are mediated through adenylyl cyclase or phosphoinositide metabolism, with subsequent enhancement of multiple downstream kinase cascades. The latter actions propagate and further amplify the receptor signals, thus predisposing D(1)-like receptors to multifaceted interactions with various other mediators and receptor systems. The adenylyl cyclase response to dopamine or selective D(1)-like receptor agonists is reliably associated with the D(1) subtype, while emerging evidence indicates that the phosphoinositide responses in native brain tissues may be preferentially mediated through stimulation of the D(5) receptor. Besides classic coupling of each receptor subtype to specific G proteins, additional biophysical models are advanced in attempts to account for differential subcellular distribution, heteromolecular oligomerization, and activity-dependent selectivity of the receptors. It is expected that significant advances in understanding of dopamine neurobiology will emerge from current and anticipated studies directed at uncovering the molecular mechanisms of D(5) coupling to phosphoinositide signaling, the structural features that might enhance pharmacological selectivity for D(5) versus D(1) subtypes, the mechanism by which dopamine may modulate phosphoinositide synthesis, the contributions of the various responsive signal mediators to D(1) or D(5) interactions with D(2)-like receptors, and the spectrum of dopaminergic functions that may be attributed to each receptor subtype and signaling pathway.
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Affiliation(s)
- Ashiwel S Undieh
- Laboratory of Integrative Neuropharmacology, Department of Pharmaceutical Sciences, Thomas Jefferson University School of Pharmacy, 130 South 9th Street, Suite 1510, Philadelphia, PA 19107, USA.
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Jose PA, Soares-da-Silva P, Eisner GM, Felder RA. Dopamine and G protein-coupled receptor kinase 4 in the kidney: role in blood pressure regulation. Biochim Biophys Acta Mol Basis Dis 2010; 1802:1259-67. [PMID: 20153824 DOI: 10.1016/j.bbadis.2010.02.004] [Citation(s) in RCA: 81] [Impact Index Per Article: 5.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/31/2009] [Revised: 02/05/2010] [Accepted: 02/07/2010] [Indexed: 12/11/2022]
Abstract
Complex interactions between genes and environment result in a sodium-induced elevation in blood pressure (salt sensitivity) and/or hypertension that lead to significant morbidity and mortality affecting up to 25% of the middle-aged adult population worldwide. Determining the etiology of genetic and/or environmentally-induced high blood pressure has been difficult because of the many interacting systems involved. Two main pathways have been implicated as principal determinants of blood pressure since they are located in the kidney (the key organ responsible for blood pressure regulation), and have profound effects on sodium balance: the dopaminergic and renin-angiotensin systems. These systems counteract or modulate each other, in concert with a host of intracellular second messenger pathways to regulate sodium and water balance. In particular, the G protein-coupled receptor kinase type 4 (GRK4) appears to play a key role in regulating dopaminergic-mediated natriuresis. Constitutively activated GRK4 gene variants (R65L, A142V, and A486V), by themselves or by their interaction with other genes involved in blood pressure regulation, are associated with essential hypertension and/or salt-sensitive hypertension in several ethnic groups. GRK4γ 142Vtransgenic mice are hypertensive on normal salt intake while GRK4γ 486V transgenic mice develop hypertension only with an increase in salt intake. GRK4 gene variants have been shown to hyperphosphorylate, desensitize, and internalize two members of the dopamine receptor family, the D(1) (D(1)R) and D(3) (D(3)R) dopamine receptors, but also increase the expression of a key receptor of the renin-angiotensin system, the angiotensin type 1 receptor (AT(1)R). Knowledge of the numerous blood pressure regulatory pathways involving angiotensin and dopamine may provide new therapeutic approaches to the pharmacological regulation of sodium excretion and ultimately blood pressure control.
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Affiliation(s)
- Pedro A Jose
- Children's National Medical Center, George Washington University for the Health Sciences, Washington, DC, USA.
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Role of dopamine receptor mechanisms in the amygdaloid modulation of fear and anxiety: Structural and functional analysis. Prog Neurobiol 2010; 90:198-216. [DOI: 10.1016/j.pneurobio.2009.10.010] [Citation(s) in RCA: 185] [Impact Index Per Article: 13.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/13/2009] [Revised: 06/05/2009] [Accepted: 10/09/2009] [Indexed: 11/18/2022]
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Stolzenberg DS, Zhang KY, Luskin K, Ranker L, Bress J, Numan M. Dopamine D(1) receptor activation of adenylyl cyclase, not phospholipase C, in the nucleus accumbens promotes maternal behavior onset in rats. Horm Behav 2010; 57:96-104. [PMID: 19799904 DOI: 10.1016/j.yhbeh.2009.09.014] [Citation(s) in RCA: 32] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 07/23/2009] [Revised: 09/21/2009] [Accepted: 09/24/2009] [Indexed: 11/24/2022]
Abstract
A body of evidence supports the idea that the mesolimbic dopamine (DA) system modulates the natural increase in responsiveness female rats show toward offspring (biological or foster) at birth. In the absence of the full hormonal changes associated with pregnancy and birth, female rats do not show immediate responsiveness toward foster offspring. Activation of the mesolimbic DA system can produce an immediate onset of maternal behavior in these females. For example, female rats that are hysterectomized and ovariectomized on day 15 of pregnancy (15HO) and presented with pups 48 hours later normally show maternal behavior after 2-3 days of pup exposure, but will show maternal behavior on day 0 of testing after microinjection of the DA D(1) receptor agonist, SKF 38393, into the nucleus accumbens (NA) at the time of pup presentation. DA D(1) receptor stimulation is known to activate cAMP intracellular signaling cascades via its stimulation of adenylyl cyclase (AC). However, some DA D(1) receptors are also linked to phospholipase C (PLC) and are capable of activating phosphatidylinositol signaling cascades. SKF 38393 stimulates both types of D(1) receptors. Here we provide evidence that the facilitatory effects of DA D(1) receptor stimulation in the NA on maternal behavior are mediated by AC-linked DA D(1) receptors. By examining the effects of intra-NA application of SKF 83822, a drug which selectively binds DA D(1)-AC receptors, or SKF 83959, a drug which selectively activates D(1)-PLC-linked receptors, we find that only SKF 83822 facilitates maternal behavior onset.
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Paspalas CD, Selemon LD, Arnsten AFT. Mapping the regulator of G protein signaling 4 (RGS4): presynaptic and postsynaptic substrates for neuroregulation in prefrontal cortex. ACTA ACUST UNITED AC 2009; 19:2145-55. [PMID: 19153107 DOI: 10.1093/cercor/bhn235] [Citation(s) in RCA: 24] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/27/2023]
Abstract
Regulator of G protein signaling 4 (RGS4) regulates intracellular signaling via G proteins and is markedly reduced in the prefrontal cortex (PFC) of patients with schizophrenia. Characterizing the expression of RGS4 within individual neuronal compartments is thus key to understanding its actions on individual G protein-coupled receptors (GPCRs). Here we present an ultrastructural reference map of RGS4 protein in macaque PFC based on immunogold electron microscopic analysis. At the soma, all labeling was asynaptic and affiliated with subsurface cistern microdomains of pyramidal neurons. The nucleus displayed most of immunoreactivity. RGS4 levels were particularly high along proximal apical dendrites and markedly decreased with distance from the soma; clustered label was present at the bifurcation into second-order branches. In distal dendrites and in spines, the protein was found flanking or directly facing the postsynaptic density of symmetric and asymmetric synapses. Axons also expressed RGS4. In fact, the density and distribution of pre- and postsynaptic labeling was correlated with the axon ultrastructure and the type of established synapses. The data indicate that RGS4 is strategically positioned to regulate not only postsynaptic but also presynaptic signaling in response to synaptic and nonsynaptic GPCR activation, having broad yet highly selective influences on multiple aspects of PFC cellular physiology.
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