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Comeo E, Goulding J, Lin CY, Groenen M, Woolard J, Kindon ND, Harwood CR, Platt S, Briddon SJ, Kilpatrick LE, Scammells PJ, Hill SJ, Kellam B. Ligand-Directed Labeling of the Adenosine A 1 Receptor in Living Cells. J Med Chem 2024; 67:12099-12117. [PMID: 38994645 DOI: 10.1021/acs.jmedchem.4c00835] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 07/13/2024]
Abstract
The study of protein function and dynamics in their native cellular environment is essential for progressing fundamental science. To overcome the requirement of genetic modification of the protein or the limitations of dissociable fluorescent ligands, ligand-directed (LD) chemistry has most recently emerged as a complementary, bioorthogonal approach for labeling native proteins. Here, we describe the rational design, development, and application of the first ligand-directed chemistry approach for labeling the A1AR in living cells. We pharmacologically demonstrate covalent labeling of A1AR expressed in living cells while the orthosteric binding site remains available. The probes were imaged using confocal microscopy and fluorescence correlation spectroscopy to study A1AR localization and dynamics in living cells. Additionally, the probes allowed visualization of the specific localization of A1ARs endogenously expressed in dorsal root ganglion (DRG) neurons. LD probes developed here hold promise for illuminating ligand-binding, receptor signaling, and trafficking of the A1AR in more physiologically relevant environments.
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Affiliation(s)
- Eleonora Comeo
- Division of Biomolecular Sciences and Medicinal Chemistry, School of Pharmacy, Biodiscovery Institute, University of Nottingham, Nottingham NG7 2RD, U.K
- Centre of Membrane Proteins and Receptors (COMPARE), University of Birmingham and University of Nottingham, The Midlands NG7 2UH, U.K
- Medicinal Chemistry, Monash Institute of Pharmaceutical Sciences, Monash University, Parkville, Victoria 3052, Australia
| | - Joëlle Goulding
- Division of Physiology, Pharmacology and Neuroscience, School of Life Sciences, Queens Medical Centre, University of Nottingham, Nottingham NG7 2UH, U.K
- Centre of Membrane Proteins and Receptors (COMPARE), University of Birmingham and University of Nottingham, The Midlands NG7 2UH, U.K
| | - Chia-Yang Lin
- Division of Biomolecular Sciences and Medicinal Chemistry, School of Pharmacy, Biodiscovery Institute, University of Nottingham, Nottingham NG7 2RD, U.K
- Centre of Membrane Proteins and Receptors (COMPARE), University of Birmingham and University of Nottingham, The Midlands NG7 2UH, U.K
| | - Marleen Groenen
- Division of Physiology, Pharmacology and Neuroscience, School of Life Sciences, Queens Medical Centre, University of Nottingham, Nottingham NG7 2UH, U.K
- Centre of Membrane Proteins and Receptors (COMPARE), University of Birmingham and University of Nottingham, The Midlands NG7 2UH, U.K
| | - Jeanette Woolard
- Division of Physiology, Pharmacology and Neuroscience, School of Life Sciences, Queens Medical Centre, University of Nottingham, Nottingham NG7 2UH, U.K
- Centre of Membrane Proteins and Receptors (COMPARE), University of Birmingham and University of Nottingham, The Midlands NG7 2UH, U.K
| | - Nicholas D Kindon
- Division of Biomolecular Sciences and Medicinal Chemistry, School of Pharmacy, Biodiscovery Institute, University of Nottingham, Nottingham NG7 2RD, U.K
- Centre of Membrane Proteins and Receptors (COMPARE), University of Birmingham and University of Nottingham, The Midlands NG7 2UH, U.K
| | - Clare R Harwood
- Division of Physiology, Pharmacology and Neuroscience, School of Life Sciences, Queens Medical Centre, University of Nottingham, Nottingham NG7 2UH, U.K
- Centre of Membrane Proteins and Receptors (COMPARE), University of Birmingham and University of Nottingham, The Midlands NG7 2UH, U.K
| | - Simon Platt
- Division of Physiology, Pharmacology and Neuroscience, School of Life Sciences, Queens Medical Centre, University of Nottingham, Nottingham NG7 2UH, U.K
- Centre of Membrane Proteins and Receptors (COMPARE), University of Birmingham and University of Nottingham, The Midlands NG7 2UH, U.K
| | - Stephen J Briddon
- Division of Physiology, Pharmacology and Neuroscience, School of Life Sciences, Queens Medical Centre, University of Nottingham, Nottingham NG7 2UH, U.K
- Centre of Membrane Proteins and Receptors (COMPARE), University of Birmingham and University of Nottingham, The Midlands NG7 2UH, U.K
| | - Laura E Kilpatrick
- Division of Biomolecular Sciences and Medicinal Chemistry, School of Pharmacy, Biodiscovery Institute, University of Nottingham, Nottingham NG7 2RD, U.K
- Centre of Membrane Proteins and Receptors (COMPARE), University of Birmingham and University of Nottingham, The Midlands NG7 2UH, U.K
| | - Peter J Scammells
- Medicinal Chemistry, Monash Institute of Pharmaceutical Sciences, Monash University, Parkville, Victoria 3052, Australia
| | - Stephen J Hill
- Division of Physiology, Pharmacology and Neuroscience, School of Life Sciences, Queens Medical Centre, University of Nottingham, Nottingham NG7 2UH, U.K
- Centre of Membrane Proteins and Receptors (COMPARE), University of Birmingham and University of Nottingham, The Midlands NG7 2UH, U.K
| | - Barrie Kellam
- Division of Biomolecular Sciences and Medicinal Chemistry, School of Pharmacy, Biodiscovery Institute, University of Nottingham, Nottingham NG7 2RD, U.K
- Centre of Membrane Proteins and Receptors (COMPARE), University of Birmingham and University of Nottingham, The Midlands NG7 2UH, U.K
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2
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Comeo E, Trinh P, Nguyen AT, Nowell CJ, Kindon ND, Soave M, Stoddart LA, White JM, Hill SJ, Kellam B, Halls ML, May LT, Scammells PJ. Development and Application of Subtype-Selective Fluorescent Antagonists for the Study of the Human Adenosine A 1 Receptor in Living Cells. J Med Chem 2021; 64:6670-6695. [PMID: 33724031 DOI: 10.1021/acs.jmedchem.0c02067] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/26/2022]
Abstract
The adenosine A1 receptor (A1AR) is a G-protein-coupled receptor (GPCR) that provides important therapeutic opportunities for a number of conditions including congestive heart failure, tachycardia, and neuropathic pain. The development of A1AR-selective fluorescent ligands will enhance our understanding of the subcellular mechanisms underlying A1AR pharmacology facilitating the development of more efficacious and selective therapies. Herein, we report the design, synthesis, and application of a novel series of A1AR-selective fluorescent probes based on 8-functionalized bicyclo[2.2.2]octylxanthine and 3-functionalized 8-(adamant-1-yl) xanthine scaffolds. These fluorescent conjugates allowed quantification of kinetic and equilibrium ligand binding parameters using NanoBRET and visualization of specific receptor distribution patterns in living cells by confocal imaging and total internal reflection fluorescence (TIRF) microscopy. As such, the novel A1AR-selective fluorescent antagonists described herein can be applied in conjunction with a series of fluorescence-based techniques to foster understanding of A1AR molecular pharmacology and signaling in living cells.
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Affiliation(s)
- Eleonora Comeo
- Medicinal Chemistry, Monash University, Parkville, Victoria 3052, Australia.,Division of Biomolecular Sciences and Medicinal Chemistry, School of Pharmacy, Biodiscovery Institute, University of Nottingham, Nottingham NG7 2RD, United Kingdom.,Centre of Membrane Proteins and Receptors (COMPARE), University of Birmingham, B15 2TT and University of Nottingham, Birmingham NG7 2UH, United Kingdom
| | - Phuc Trinh
- Drug Discovery Biology, Monash Institute of Pharmaceutical Sciences, Monash University, Parkville, Victoria 3052, Australia
| | - Anh T Nguyen
- Drug Discovery Biology, Monash Institute of Pharmaceutical Sciences, Monash University, Parkville, Victoria 3052, Australia
| | - Cameron J Nowell
- Drug Discovery Biology, Monash Institute of Pharmaceutical Sciences, Monash University, Parkville, Victoria 3052, Australia
| | - Nicholas D Kindon
- Division of Biomolecular Sciences and Medicinal Chemistry, School of Pharmacy, Biodiscovery Institute, University of Nottingham, Nottingham NG7 2RD, United Kingdom.,Centre of Membrane Proteins and Receptors (COMPARE), University of Birmingham, B15 2TT and University of Nottingham, Birmingham NG7 2UH, United Kingdom
| | - Mark Soave
- Division of Physiology, Pharmacology and Neuroscience, School of Life Sciences, Queens Medical Centre, University of Nottingham, Nottingham NG7 2UH, United Kingdom.,Centre of Membrane Proteins and Receptors (COMPARE), University of Birmingham, B15 2TT and University of Nottingham, Birmingham NG7 2UH, United Kingdom
| | - Leigh A Stoddart
- Division of Physiology, Pharmacology and Neuroscience, School of Life Sciences, Queens Medical Centre, University of Nottingham, Nottingham NG7 2UH, United Kingdom.,Centre of Membrane Proteins and Receptors (COMPARE), University of Birmingham, B15 2TT and University of Nottingham, Birmingham NG7 2UH, United Kingdom
| | - Jonathan M White
- School of Chemistry and the Bio21 Molecular Science and Biotechnology Institute, The University of Melbourne, Melbourne, Victoria 3010, Australia
| | - Stephen J Hill
- Division of Physiology, Pharmacology and Neuroscience, School of Life Sciences, Queens Medical Centre, University of Nottingham, Nottingham NG7 2UH, United Kingdom.,Centre of Membrane Proteins and Receptors (COMPARE), University of Birmingham, B15 2TT and University of Nottingham, Birmingham NG7 2UH, United Kingdom
| | - Barrie Kellam
- Division of Biomolecular Sciences and Medicinal Chemistry, School of Pharmacy, Biodiscovery Institute, University of Nottingham, Nottingham NG7 2RD, United Kingdom.,Centre of Membrane Proteins and Receptors (COMPARE), University of Birmingham, B15 2TT and University of Nottingham, Birmingham NG7 2UH, United Kingdom
| | - Michelle L Halls
- Drug Discovery Biology, Monash Institute of Pharmaceutical Sciences, Monash University, Parkville, Victoria 3052, Australia
| | - Lauren T May
- Drug Discovery Biology, Monash Institute of Pharmaceutical Sciences, Monash University, Parkville, Victoria 3052, Australia
| | - Peter J Scammells
- Medicinal Chemistry, Monash University, Parkville, Victoria 3052, Australia
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3
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Abdulla HO, Amin AA, Raviola C, Opatz T, Protti S, Fagnoni M. Smooth Metal-Free Photoinduced Preparation of Valuable 8-Arylxanthines. European J Org Chem 2019. [DOI: 10.1002/ejoc.201900638] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/13/2023]
Affiliation(s)
- Havall Othman Abdulla
- PhotoGreen Lab; Department of Chemistry; University of Pavia; Viale Taramelli 12 27100 Pavia Italy
- Chemistry Department; College of Science; Salahaddin University; Erbil Iraq
| | - Ahmed A. Amin
- Chemistry Department; College of Education; Salahaddin University; Erbil Iraq
| | - Carlotta Raviola
- PhotoGreen Lab; Department of Chemistry; University of Pavia; Viale Taramelli 12 27100 Pavia Italy
| | - Till Opatz
- Institute of Organic Chemistry; College of Education; Johannes Gutenberg University of Mainz; 55128 Mainz Germany
| | - Stefano Protti
- PhotoGreen Lab; Department of Chemistry; University of Pavia; Viale Taramelli 12 27100 Pavia Italy
| | - Maurizio Fagnoni
- PhotoGreen Lab; Department of Chemistry; University of Pavia; Viale Taramelli 12 27100 Pavia Italy
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4
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Cao R, Rossetti G, Bauer A, CarIoni P. Binding of the Antagonist Caffeine to the Human Adenosine Receptor hA2AR in Nearly Physiological Conditions. PLoS One 2015; 10:e0126833. [PMID: 25992797 PMCID: PMC4439127 DOI: 10.1371/journal.pone.0126833] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/13/2015] [Accepted: 04/08/2015] [Indexed: 12/27/2022] Open
Abstract
Lipid composition may significantly affect membrane proteins function, yet its impact on the protein structural determinants is not well understood. Here we present a comparative molecular dynamics (MD) study of the human adenosine receptor type 2A (hA(2A)R) in complex with caffeine--a system of high neuro-pharmacological relevance--within different membrane types. These are POPC, mixed POPC/POPE and cholesterol-rich membranes. 0.8-μs MD simulations unambiguously show that the helical folding of the amphipathic helix 8 depends on membrane contents. Most importantly, the distinct cholesterol binding into the cleft between helix 1 and 2 stabilizes a specific caffeine-binding pose against others visited during the simulation. Hence, cholesterol presence (~33%-50% in synaptic membrane in central nervous system), often neglected in X-ray determination of membrane proteins, affects the population of the ligand binding poses. We conclude that including a correct description of neuronal membranes may be very important for computer-aided design of ligands targeting hA(2A)R and possibly other GPCRs.
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Affiliation(s)
- Ruyin Cao
- German Research School for Simulation Sciences (joint venture of RWTH Aachen University and Forschungszentrum Jülich GmbH), D-52425, Jülich, Germany
- Computational Biomedicine, Institute for Advanced Simulation (IAS-5), Forschungszentrum Jülich GmbH, D-52425, Jülich, Germany
| | - Giulia Rossetti
- German Research School for Simulation Sciences (joint venture of RWTH Aachen University and Forschungszentrum Jülich GmbH), D-52425, Jülich, Germany
- Computational Biomedicine, Institute for Advanced Simulation (IAS-5), Forschungszentrum Jülich GmbH, D-52425, Jülich, Germany
- Institute of Neuroscience and Medicine (INM-9), Forschungszentrum Jülich GmbH, D-52425, Jülich, Germany
- Jülich Supercomputing Centre (JSC), Forschungszentrum Jülich GmbH, D-52425, Jülich, Germany
| | - Andreas Bauer
- Institute of Neuroscience and Medicine (INM-2), Forschungszentrum Jülich GmbH, D-52425, Jülich, Germany
| | - Paolo CarIoni
- German Research School for Simulation Sciences (joint venture of RWTH Aachen University and Forschungszentrum Jülich GmbH), D-52425, Jülich, Germany
- Computational Biomedicine, Institute for Advanced Simulation (IAS-5), Forschungszentrum Jülich GmbH, D-52425, Jülich, Germany
- Institute of Neuroscience and Medicine (INM-9), Forschungszentrum Jülich GmbH, D-52425, Jülich, Germany
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5
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Abstract
The natural plant alkaloids caffeine and theophylline were the first adenosine receptor (AR) antagonists described in the literature. They exhibit micromolar affinities and are non-selective. A large number of derivatives and analogues were subsequently synthesized and evaluated as AR antagonists. Very potent antagonists have thus been developed with selectivity for each of the four AR subtypes.
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Affiliation(s)
- Christa Müller
- PharmaCenter Bonn, Pharmaceutical Sciences Bonn (PSB), University of Bonn, Pharmaceutical Institute, Pharmaceutical Chemistry I, An der Immenburg 4, D-53121 Bonn, Germany, Phone +49-228-73-2301, Fax +49-228-73-2567
| | - Kenneth A. Jacobson
- Molecular Recognition Section, Laboratory of Bioorganic Chemistry, National Institute of Diabetes and Digestive and Kidney Diseases, National Institutes of Health, Bldg. 8A, Rm. B1A-19, NIH, NIDDK, LBC, Bethesda, MD 20892, United States of America, Phone +1-301-496-9024, Fax +1-301-480-8422
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6
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Stefanachi A, Nicolotti O, Leonetti F, Cellamare S, Campagna F, Loza MI, Brea JM, Mazza F, Gavuzzo E, Carotti A. 1,3-Dialkyl-8-(hetero)aryl-9-OH-9-deazaxanthines as potent A2B adenosine receptor antagonists: Design, synthesis, structure–affinity and structure–selectivity relationships. Bioorg Med Chem 2008; 16:9780-9. [DOI: 10.1016/j.bmc.2008.09.067] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/17/2008] [Revised: 09/19/2008] [Accepted: 09/26/2008] [Indexed: 11/29/2022]
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7
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Yoshida T. Synthetic and Natural Polysaccharides Having Specific Biological Activities. POLYSACCHARIDES 2004. [DOI: 10.1201/9781420030822.ch37] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022] Open
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8
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De Esch IJ, Vollinga RC, Goubitz K, Schenk H, Appelberg U, Hacksell U, Lemstra S, Zuiderveld OP, Hoffmann M, Leurs R, Menge WM, Timmerman H. Characterization of the binding site of the histamine H3 receptor. 1. Various approaches to the synthesis of 2-(1H-imidazol-4-yl)cyclopropylamine and histaminergic activity of (1R,2R)- and (1S,2S)-2-(1H-imidazol-4-yl)-cyclopropylamine. J Med Chem 1999; 42:1115-22. [PMID: 10197956 DOI: 10.1021/jm9810912] [Citation(s) in RCA: 19] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
Various approaches to the synthesis of all four stereoisomers of 2-(1H-imidazol-4-yl)cyclopropylamine (cyclopropylhistamine) are described. The rapid and convenient synthesis and resolution of trans-cyclopropylhistamine is reported. The absolute configuration of its enantiomers was determined by single-crystal X-ray crystallographic analysis. The distinct trans-cyclopropylhistamine enantiomers were tested for their activity and affinity on the histamine H3 receptor. (1S,2S)-Cyclopropylhistamine (VUF 5297) acts as an agonist both on the rat cortex (pD2 = 7.1; alpha = 0.75) and on guinea pig jejunum (pD2 = 6.6; alpha = 0.75). Its enantiomer, (1R, 2R)-cyclopropylhistamine (VUF 5296), is about 1 order of magnitude less active. Both enantiomers show weak activity on H1 and H2 receptors. All synthetic attempts to cis-cyclopropylhistamine were unsuccessful. Nevertheless, the results of this study provide an ideal template for molecular modeling studies of histamine H3 receptor ligands.
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Affiliation(s)
- I J De Esch
- Leiden/Amsterdam Center for Drug Research, Division of Medicinal Chemistry, Department of Pharmacochemistry, Faculty of Chemistry, Vrije Universiteit, De Boelelaan 1083, 1081 HV Amsterdam, The Netherlands
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9
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Hernández F, Kendall DA, Alexander SP. Adenosine receptor-induced second messenger production in adult guinea-pig cerebellum. Br J Pharmacol 1993; 110:1085-90. [PMID: 8298796 PMCID: PMC2175816 DOI: 10.1111/j.1476-5381.1993.tb13925.x] [Citation(s) in RCA: 16] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/29/2023] Open
Abstract
1. The effects of adenosine receptor agonists on cyclic nucleotides accumulation were investigated in adult guinea-pig cerebellar slices by use of radioactive precursors. 2. Adenosine elicited a rapid and maintained increase in cyclic AMP, that was fully reversed upon addition of adenosine deaminase. Adenosine analogues stimulated cyclic AMP generation up to 40 fold with the rank order of potency: 5'-N-ethylcarboxamidoadenosine (0.6 microM) > 2-chloroadenosine (6 microM) > adenosine (13 microM). CGS 21680 (10 microM) elicited only a small stimulation (1.2 fold). 3. The cyclic AMP response to NECA was reversed by the 1,3-dipropylxanthine-based adenosine receptor antagonists 8-[4-[[[[(2-aminoethyl)amino]amino]carbonyl]methyl]oxy]- phenyl]-1,3-dipropylxanthine (XAC), 8-cyclopentyl-1,3-dipropylxanthine (DPCPX) and N-[2-(dimethylamino)ethyl]N-methyl-4-(1,3-dipropylxanthine)benzene sulphonamide (PD 115,199) with estimated apparent inhibition constants of 15, 81 and 117 nM, respectively. 4. Pretreatment with adenosine also potentiated the cyclic GMP response to sodium nitroprusside, abolishing the decline in [3H]-cyclic GMP observed with sodium nitroprusside alone, and allowing [3H]-cyclic GMP levels to be maintained for at least an additional 10 min. This potentiation was fully reversed by adenosine deaminase. 5. Adenosine analogues potentiated the sodium nitroprusside-elicited cyclic GMP generation with the rank order of potency: 5'-N-ethylcarboxamidoadenosine (0.7 microM) > 2-chloroadenosine (6 microM) > adenosine (42 microM). 6. NECA potentiation of cyclic GMP formation was reversed by the antagonists XAC, DPCPX and PD 115,199 with apparent inhibition constants of 17, 102 and 242 nM, respectively. 7. The similar potencies of adenosine analogues and xanthine antagonists for stimulation of cyclic AMP and potentiation of cyclic GMP lead to the suggestion that these phenomena are mediated through the same adenosine receptor, the A2b receptor. Furthermore, we suggest that potentiation of the sodium nitroprusside-induced cyclic GMP response may be mediated at the level of phosphodiesterase hydrolysis of the cyclic nucleotides.
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Affiliation(s)
- F Hernández
- Department of Physiology & Pharmacology, University of Nottingham Medical School, Queen's Medical Centre
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10
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Abstract
The identification and characterization of adenosine receptors and the development of potent, receptor subtype-selective agonists and antagonists has been an active area of research for the past 20 years. Major recent advances in the field have been the cloning of several adenosine receptor subtypes of different species, including the discovery of a new subtype, designated A3, the discovery and development of new agonists and antagonists, particularly those with selectivity for the A2a adenosine receptor, the characterization of signal transduction pathways, and the development of agents which act indirectly on the adenosine receptor system. The present article focusses on aspects of pharmaceutical/medicinal chemistry related to adenosine receptors.
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Affiliation(s)
- C E Müller
- Pharmazeutisches Institut, Pharmazeutische Chemie, Tübingen, Germany
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11
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Lee TF, Li DJ, Jacobson KA, Wang LC. Improvement of cold tolerance by selective A1 adenosine receptor antagonists in rats. Pharmacol Biochem Behav 1990; 37:107-12. [PMID: 2263650 PMCID: PMC4516057 DOI: 10.1016/0091-3057(90)90049-n] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/31/2022]
Abstract
Previously we have shown that the improvement of cold tolerance by theophylline is due to antagonism at adenosine receptors rather than inhibition of phosphodiesterase. Since theophylline is a nonselective adenosine receptor antagonist for both A1 and A2 receptors, the present study investigated the adenosine receptor subtype involved in theophylline's action. Acute systemic injection of selective A1 receptor antagonists (1,3-dialkyl-8-aryl or 1,3-dialkyl-8-cyclopentyl xanthine derivatives) significantly increased both the total and maximal heat production as well as cold tolerance. In contrast, injection of a relatively selective A2 receptor antagonist, 3,7-dimethyl-1-propargylxanthine (compound No. 19), failed to significantly alter the thermogenic response of the rat under cold exposure. Further, the relative effectiveness of these compounds in increasing total thermogenesis was positively correlated with their potency in blocking the A1 adenosine receptor (r = .52, p less than 0.01), but not in A2 adenosine receptor (r = .20, p less than 0.2). It is likely that the thermally beneficial effects of adenosine A1 antagonists are due to their attenuation of the inhibitory effects of endogenously released adenosine on lipolysis and glucose utilization, resulting in increased substrate mobilization and utilization for enhanced thermogenesis.
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Affiliation(s)
- T F Lee
- Zoology Department, University of Alberta, Edmonton, Canada
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12
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Jacobson KA, Kiriasis L, Barone S, Bradbury BJ, Kammula U, Campagne JM, Secunda S, Daly JW, Neumeyer JL, Pfleiderer W. Sulfur-containing 1,3-dialkylxanthine derivatives as selective antagonists at A1-adenosine receptors. J Med Chem 1989; 32:1873-9. [PMID: 2754711 PMCID: PMC3479653 DOI: 10.1021/jm00128a031] [Citation(s) in RCA: 32] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/02/2023]
Abstract
Sulfur-containing analogues of 8-substituted xanthines were prepared in an effort to increase selectivity or potency as antagonists at adenosine receptors. Either cyclopentyl or various aryl substituents were utilized at the 8-position, because of the association of these groups with high potency at A1-adenosine receptors. Sulfur was incorporated on the purine ring at positions 2 and/or 6, in the 8-position substituent in the form of 2- or 3-thienyl groups, or via thienyl groups separated from an 8-aryl substituent through an amide-containing chain. The feasibility of using the thienyl group as a prosthetic group for selective iodination via its Hg2+ derivative was explored. Receptor selectivity was determined in binding assays using membrane homogenates from rat cortex [( 3H]-N6-(phenylisopropyl)adenosine as radioligand] or striatum [3H]-5'-(N-ethylcarbamoyl)adenosine as radioligand] for A1- and A2-adenosine receptors, respectively. Generally, 2-thio-8-cycloalkylxanthines were at least as A1 selective as the corresponding oxygen analogue. 2-Thio-8-aryl derivatives tended to be more potent at A2 receptors than the oxygen analogue. 8-[4-[(Carboxy-methyl)oxyl] phenyl]-1,3-dipropyl-2-thioxanthine ethyl ester was greater than 740-fold A1 selective.
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Affiliation(s)
- K A Jacobson
- Laboratory of Chemistry, NIDDK, Bethesda, Maryland 20892
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13
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14
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Jacobson KA, de la Cruz R, Schulick R, Kiriasis L, Padgett W, Pfleiderer W, Kirk KL, Neumeyer JL, Daly JW. 8-Substituted xanthines as antagonists at A1- and A2-adenosine receptors. Biochem Pharmacol 1988; 37:3653-61. [PMID: 3178879 PMCID: PMC3469272 DOI: 10.1016/0006-2952(88)90398-x] [Citation(s) in RCA: 25] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/04/2023]
Abstract
Two classes of 8-substituted analogs of theophylline (1,3-dialkylxanthines), having 8-cycloalkyl, 8-cycloalkenyl or 8-(para-substituted aryl) groups, were shown to be potent and, in some cases, receptor subtype selective antagonists at A1- and A2-adenosine receptors. New analogs based on a functionalized cogener approach and on classical medicinal chemical approaches were prepared. Affinity at A1-adenosine receptors was evaluated by inhibition of binding of [3H]N6-phenylisopropyladenosine to rat brain membranes. Activity at A2-adenosine receptors was measured by the reversal of 5'-N-ethylcarboxamidoadenosine (NECA)-stimulated production of cyclic AMP in membranes from rat pheochromocytoma PC12 cells. Cycloalkenyl analogs containing rigid olefinic bonds differed greatly in potency from the saturated analogs. The selectivity of phenylsulfonamide analogs depended on distal structural features. Novel xanthine analogs include diamino-, thiol-, aldehyde, and halogen-substituted derivatives, peptide conjugates of 8-[4-[2-aminoethylaminocarbonylmethyloxy]phenyl]1,3-dipropylxan thi ne (XAC), and a hydroxyethylamide analog of XAC.
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Affiliation(s)
- K A Jacobson
- Laboratory of Chemistry, NIDDK, Bethesda, MD 20892
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