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Villalobos Sambucaro MJ, Alzugaray ME, Ronderos JR. Mechanisms controlling haemolymph circulation under resting conditions in the Chagas disease vector Rhodnius prolixus. J Exp Biol 2024; 227:jeb247801. [PMID: 38989599 DOI: 10.1242/jeb.247801] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/03/2024] [Accepted: 07/05/2024] [Indexed: 07/12/2024]
Abstract
Chagas disease vectors can ingest several times their own volume in blood with each meal. This ad libitum feeding causes an intense process of diuresis, inducing the insect to eliminate a large quantity of urine and faeces. To ensure diuresis, the speed of circulation of the haemolymph is increased. The Triatominae circulatory system is quite simple, including the dorsal vessel, which pumps haemolymph in an anterograde direction. The return is caused by peristaltic contractions of the anterior midgut. Triatominae insects can spend several weeks without feeding, meaning that most of the time, the insect is in a resting condition. Although the mechanisms controlling the circulation of the haemolymph during post-prandial diuresis have been largely analysed, the mechanisms controlling it during resting conditions are poorly understood. In this study, we analysed several canonical pathways (i.e. L-type VGCC, GPCR, RyR, IP3R) and a novel system represented by the recently characterized Piezo proteins. Our results show that during the resting condition, haemolymph circulation depends on a cross-talk between myogenic activity, inhibitory and stimulatory cellular messengers, and Piezo proteins. This report also unveils for the first time the existence of a putative Piezo protein in Hemiptera.
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Affiliation(s)
- María José Villalobos Sambucaro
- Cátedra de Histología y Embriología Animal, Facultad de Ciencias Naturales y Museo, Universidad Nacional de La Plata, 1900 La Plata, Buenos Aires, Argentina
- CONICET, Godoy Cruz 2290, CABA, Argentina
| | - María Eugenia Alzugaray
- Cátedra de Histología y Embriología Animal, Facultad de Ciencias Naturales y Museo, Universidad Nacional de La Plata, 1900 La Plata, Buenos Aires, Argentina
- CONICET, Godoy Cruz 2290, CABA, Argentina
| | - Jorge Rafael Ronderos
- Cátedra de Histología y Embriología Animal, Facultad de Ciencias Naturales y Museo, Universidad Nacional de La Plata, 1900 La Plata, Buenos Aires, Argentina
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Gao ZG, Auchampach JA, Jacobson KA. Species dependence of A 3 adenosine receptor pharmacology and function. Purinergic Signal 2023; 19:523-550. [PMID: 36538251 PMCID: PMC9763816 DOI: 10.1007/s11302-022-09910-1] [Citation(s) in RCA: 6] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/22/2022] [Accepted: 11/26/2022] [Indexed: 12/24/2022] Open
Abstract
Efforts to fully understand pharmacological differences between G protein-coupled receptor (GPCR) species homologues are generally not pursued in detail during the drug development process. To date, many GPCRs that have been successfully targeted are relatively well-conserved across species in amino acid sequence and display minimal variability of biological effects. However, the A3 adenosine receptor (AR), an exciting drug target for a multitude of diseases associated with tissue injury, ischemia, and inflammation, displays as little as 70% sequence identity among mammalian species (e.g., rodent vs. primate) commonly used in drug development. Consequently, the pharmacological properties of synthetic A3AR ligands vary widely, not only in binding affinity, selectivity, and signaling efficacy, but to the extent that some function as agonists in some species and antagonists in others. Numerous heterocyclic antagonists that have nM affinity at the human A3AR are inactive or weakly active at the rat and mouse A3ARs. Positive allosteric modulators, including the imidazo [4,5-c]quinolin-4-amine derivative LUF6000, are only active at human and some larger animal species that have been evaluated (rabbit and dog), but not rodents. A3AR agonists evoke systemic degranulation of rodent, but not human mast cells. The rat A3AR undergoes desensitization faster than the human A3AR, but the human homologue can be completely re-sensitized and recycled back to the cell surface. Thus, comprehensive pharmacological evaluation and awareness of potential A3AR species differences are critical in studies to further understand the basic biological functions of this unique AR subtype. Recombinant A3ARs from eight different species have been pharmacologically characterized thus far. In this review, we describe in detail current knowledge of species differences in genetic identity, G protein-coupling, receptor regulation, and both orthosteric and allosteric A3AR pharmacology.
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Affiliation(s)
- Zhan-Guo Gao
- Molecular Recognition Section, Laboratory of Bioorganic Chemistry, National Institute of Diabetes and Digestive and Kidney Diseases, National Institutes of Health, Bethesda, MD, 20892-0810, USA.
| | - John A Auchampach
- Department of Pharmacology and Toxicology, and the Cardiovascular Center, Medical College of Wisconsin, 8701 Watertown Plank Road, Milwaukee, WI, 53226, USA
| | - Kenneth A Jacobson
- Molecular Recognition Section, Laboratory of Bioorganic Chemistry, National Institute of Diabetes and Digestive and Kidney Diseases, National Institutes of Health, Bethesda, MD, 20892-0810, USA.
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Alzugaray ME, Gavazzi MV, Ronderos JR. G protein-coupled receptor signal transduction and Ca 2+ signaling pathways of the allatotropin/orexin system in Hydra. Gen Comp Endocrinol 2021; 300:113637. [PMID: 33017583 DOI: 10.1016/j.ygcen.2020.113637] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 05/06/2020] [Revised: 09/16/2020] [Accepted: 09/28/2020] [Indexed: 11/24/2022]
Abstract
Allatotropin is a pleiotropic peptide originally characterized in insects. The existence of AT neuropeptide signaling was proposed in other invertebrates. In fact, we previously proposed the presence of an AT-like system regulating feeding behavior in Hydra sp. Even in insects, the information about the AT signaling pathway is incomplete. The aim of this study is to analyze the signaling cascade activated by AT in Hydra plagiodesmica using a pharmacological approach. The results show the involvement of Ca2+ and IP3 signaling in the transduction pathway of the peptide. Furthermore, we confirm the existence of a GPCR system involved in this pathway, that would be coupled to a Gq subfamily of Gα protein, which activates a PLC, inducing an increase in IP3 and cytosolic Ca2+. To the best of our knowledge, this work represents the first in vivo approach to study the overall signaling pathway and intracellular events involved in the myoregulatory effect of AT in Hydra sp.
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Affiliation(s)
- María Eugenia Alzugaray
- Cátedra de Histología y Embriología Animal. Facultad de Ciencias Naturales y Museo, Universidad Nacional de La Plata (FCNyM-UNLP), Argentina; Consejo Nacional de Investigaciones Científicas y Técnicas (CONICET), Argentina
| | - María Victoria Gavazzi
- Cátedra de Histología y Embriología Animal. Facultad de Ciencias Naturales y Museo, Universidad Nacional de La Plata (FCNyM-UNLP), Argentina; Consejo Nacional de Investigaciones Científicas y Técnicas (CONICET), Argentina
| | - Jorge Rafael Ronderos
- Cátedra de Histología y Embriología Animal. Facultad de Ciencias Naturales y Museo, Universidad Nacional de La Plata (FCNyM-UNLP), Argentina.
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Wold EA, Chen J, Cunningham KA, Zhou J. Allosteric Modulation of Class A GPCRs: Targets, Agents, and Emerging Concepts. J Med Chem 2019; 62:88-127. [PMID: 30106578 PMCID: PMC6556150 DOI: 10.1021/acs.jmedchem.8b00875] [Citation(s) in RCA: 95] [Impact Index Per Article: 19.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/06/2023]
Abstract
G-protein-coupled receptors (GPCRs) have been tractable drug targets for decades with over one-third of currently marketed drugs targeting GPCRs. Of these, the class A GPCR superfamily is highly represented, and continued drug discovery for this family of receptors may provide novel therapeutics for a vast range of diseases. GPCR allosteric modulation is an innovative targeting approach that broadens the available small molecule toolbox and is proving to be a viable drug discovery strategy, as evidenced by recent FDA approvals and clinical trials. Numerous class A GPCR allosteric modulators have been discovered recently, and emerging trends such as the availability of GPCR crystal structures, diverse functional assays, and structure-based computational approaches are improving optimization and development. This Perspective provides an update on allosterically targeted class A GPCRs and their disease indications and the medicinal chemistry approaches toward novel allosteric modulators and highlights emerging trends and opportunities in the field.
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Affiliation(s)
- Eric A. Wold
- Department of Pharmacology and Toxicology, Chemical Biology Program, University of Texas Medical Branch, Galveston, Texas 77555, United States
- Department of Pharmacology and Toxicology, Center for Addiction Research, University of Texas Medical Branch, Galveston, Texas 77555, United States
| | - Jianping Chen
- Department of Pharmacology and Toxicology, Chemical Biology Program, University of Texas Medical Branch, Galveston, Texas 77555, United States
- Department of Pharmacology and Toxicology, Center for Addiction Research, University of Texas Medical Branch, Galveston, Texas 77555, United States
| | - Kathryn A. Cunningham
- Department of Pharmacology and Toxicology, Chemical Biology Program, University of Texas Medical Branch, Galveston, Texas 77555, United States
- Department of Pharmacology and Toxicology, Center for Addiction Research, University of Texas Medical Branch, Galveston, Texas 77555, United States
| | - Jia Zhou
- Department of Pharmacology and Toxicology, Chemical Biology Program, University of Texas Medical Branch, Galveston, Texas 77555, United States
- Department of Pharmacology and Toxicology, Center for Addiction Research, University of Texas Medical Branch, Galveston, Texas 77555, United States
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Paillamanque J, Sanchez-Tusie A, Carmona EM, Treviño CL, Sandoval C, Nualart F, Osses N, Reyes JG. Arachidonic acid triggers [Ca2+]i increases in rat round spermatids by a likely GPR activation, ERK signalling and ER/acidic compartments Ca2+ release. PLoS One 2017; 12:e0172128. [PMID: 28192519 PMCID: PMC5305069 DOI: 10.1371/journal.pone.0172128] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/22/2016] [Accepted: 01/31/2017] [Indexed: 12/27/2022] Open
Abstract
Arachidonic acid (AA), a compound secreted by Sertoli cells (SC) in a FSH-dependent manner, is able to induce the release of Ca2+ from internal stores in round spermatids and pachytene spermatocytes. In this study, the possible site(s) of action of AA in round spermatids, the signalling pathways associated and the intracellular Ca2+ stores targeted by AA-induced signalling were pharmacologically characterized by measuring intracellular Ca2+ using fluorescent Ca2+ probes. Our results suggest that AA acts by interacting with a fatty acid G protein coupled receptor, initiating a G protein signalling cascade that may involve PLA2 and ERK activation, which in turn opens intracellular ryanodine-sensitive channels as well as NAADP-sensitive channels in acidic intracellular Ca2+ stores. The results presented here also suggest that AMPK and PKA modulate this AA-induced Ca2+ release from intracellular Ca2+ stores in round spermatids. We propose that unsaturated free fatty acid lipid signalling in the seminiferous tubule is a novel regulatory component of rat spermatogenesis.
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Affiliation(s)
- Joaquin Paillamanque
- Instituto de Química, Pontificia Universidad Católica de Valparaíso, Valparaíso, Chile
| | - Ana Sanchez-Tusie
- Departamento de Genética del Desarrollo y Fisiología Molecular, Instituto de Biotecnología, Universidad Autónoma de México, Cuernavaca, México
| | - Emerson M. Carmona
- Instituto de Química, Pontificia Universidad Católica de Valparaíso, Valparaíso, Chile
| | - Claudia L. Treviño
- Departamento de Genética del Desarrollo y Fisiología Molecular, Instituto de Biotecnología, Universidad Autónoma de México, Cuernavaca, México
| | - Carolina Sandoval
- Instituto de Química, Pontificia Universidad Católica de Valparaíso, Valparaíso, Chile
| | - Francisco Nualart
- Departamento de Biología Celular, Facultad de Ciencias Biológicas, Universidad de Concepción, Concepción, Chile
| | - Nelson Osses
- Instituto de Química, Pontificia Universidad Católica de Valparaíso, Valparaíso, Chile
| | - Juan G. Reyes
- Instituto de Química, Pontificia Universidad Católica de Valparaíso, Valparaíso, Chile
- * E-mail:
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Deokar H, Chaskar J, Chaskar A. Synthesis and Antimicrobial Activity Evaluation of Novel Oxadiazino/Thiadiazino-Indole and Oxadiazole/Thiadiazole Derivatives of 2-Oxo-2H-benzopyran. J Heterocycl Chem 2013. [DOI: 10.1002/jhet.1761] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
Affiliation(s)
- H. Deokar
- C. K. Thakur Research Centre; Navi Mumbai 410206 India
| | - J. Chaskar
- Department of Biotechnology; C. K.Thakur College; Navi Mumbai
| | - A. Chaskar
- C. K. Thakur Research Centre; Navi Mumbai 410206 India
- Department of Chemistry; National Taiwan University; Taipei Taiwan
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Ondrackova P, Kovaru H, Kovaru F, Matiasovic J, Leva L, Faldyna M. The effect of adenosine on pro-inflammatory cytokine production by porcine T cells. Vet Immunol Immunopathol 2011; 145:332-9. [PMID: 22222199 DOI: 10.1016/j.vetimm.2011.12.002] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/27/2011] [Revised: 12/02/2011] [Accepted: 12/04/2011] [Indexed: 01/05/2023]
Abstract
Adenosine is a well described anti-inflammatory modulator of immune responses. The aim of the present study was to describe the role of common adenosine agonist 5'-N-ethylcarboxamidoadenosine (NECA) in cytokine production by main porcine T cell subpopulations. TNF-α, IFN-γ, IL-2 and IL-10 were detected by multicolor flow cytometry together with cell surface markers CD3, CD4 and CD8. It was found that NECA inhibits (in a dose-dependent manner) production of pro-inflammatory TNF-α and Th1-associated cytokines IFN-γ, IL-2 in all concanavalin A-stimulated T cell subpopulations. Moreover, production of IL-10 was potentiated in all T cell subpopulations tested. These corresponded well with the fact that all T cell subsets expressed mRNA for adenosine receptor (AR) subtypes to comparable extents. Contrary to concanavalin A-stimulated cells, NECA had a moderate effect on PMA-stimulated T cells, suggesting that AR in pigs acts via signaling pathways not associated with protein-kinase C. Non-selective antagonist CGS15943 as well as allosteric modulator SCH202676 failed to reverse the effect of NECA in pigs. In conclusion, NECA has an anti-inflammatory effect on porcine T cell subpopulations.
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Affiliation(s)
- Petra Ondrackova
- Veterinary Research Institute, Hudcova 70, 621 00 Brno, Czech Republic
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Cheong SL, Federico S, Venkatesan G, Mandel AL, Shao YM, Moro S, Spalluto G, Pastorin G. The A3 adenosine receptor as multifaceted therapeutic target: pharmacology, medicinal chemistry, and in silico approaches. Med Res Rev 2011; 33:235-335. [PMID: 22095687 DOI: 10.1002/med.20254] [Citation(s) in RCA: 35] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/21/2022]
Abstract
Adenosine is an ubiquitous local modulator that regulates various physiological and pathological functions by stimulating four membrane receptors, namely A(1), A(2A), A(2B), and A(3). Among these G protein-coupled receptors, the A(3) subtype is found mainly in the lung, liver, heart, eyes, and brain in our body. It has been associated with cerebroprotection and cardioprotection, as well as modulation of cellular growth upon its selective activation. On the other hand, its inhibition by selective antagonists has been reported to be potentially useful in the treatment of pathological conditions including glaucoma, inflammatory diseases, and cancer. In this review, we focused on the pharmacology and the therapeutic implications of the human (h)A(3) adenosine receptor (AR), together with an overview on the progress of hA(3) AR agonists, antagonists, allosteric modulators, and radioligands, as well as on the recent advances pertaining to the computational approaches (e.g., quantitative structure-activity relationships, homology modeling, molecular docking, and molecular dynamics simulations) applied to the modeling of hA(3) AR and drug design.
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Affiliation(s)
- Siew Lee Cheong
- Department of Pharmacy, National University of Singapore, 3 Science Drive 2, Singapore 117543, Singapore
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9
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Jacobson KA, Gao ZG, Göblyös A, IJzerman AP. Allosteric modulation of purine and pyrimidine receptors. ADVANCES IN PHARMACOLOGY (SAN DIEGO, CALIF.) 2011; 61:187-220. [PMID: 21586360 PMCID: PMC3165024 DOI: 10.1016/b978-0-12-385526-8.00007-2] [Citation(s) in RCA: 27] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/13/2022]
Abstract
Among the purine and pyrimidine receptors, the discovery of small molecular allosteric modulators has been most highly advanced for the A(1) and A(3) adenosine receptors (ARs). These AR modulators have allosteric effects that are structurally separated from the orthosteric effects in SAR studies. The benzoylthiophene derivatives tend to act as allosteric agonists as well as selective positive allosteric modulators (PAMs) of the A(1) AR. A 2-amino-3-aroylthiophene derivative T-62 has been under development as a PAM of the A(1) AR for the treatment of chronic pain. Several structurally distinct classes of allosteric modulators of the human A(3) AR have been reported: 3-(2-pyridinyl)isoquinolines, 2,4-disubstituted quinolines, 1H-imidazo-[4,5-c]quinolin-4-amines, endocannabinoid 2-arachidonylglycerol, and the food dye Brilliant Black BN. Site-directed mutagenesis of A(1) and A(3) ARs has identified residues associated with the allosteric effect, distinct from those that affect orthosteric binding. A few small molecular allosteric modulators have been reported for several of the P2X ligand-gated ion channels and the G protein-coupled P2Y receptor nucleotides. Metal ion modulation of the P2X receptors has been extensively explored. The allosteric approach to modulation of purine and pyrimidine receptors looks promising for development of drugs that are event and site specific in action.
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Affiliation(s)
- Kenneth A. Jacobson
- Molecular Recognition Section, Laboratory of Bioorganic Chemistry, National Institute of Diabetes and Digestive and Kidney Diseases, National Institutes of Health, Bethesda, MD 20892, USA
| | - Zhan-Guo Gao
- Molecular Recognition Section, Laboratory of Bioorganic Chemistry, National Institute of Diabetes and Digestive and Kidney Diseases, National Institutes of Health, Bethesda, MD 20892, USA
| | - Anikó Göblyös
- Division of Medicinal Chemistry, Leiden/Amsterdam Center for Drug Research, Leiden University, P.O. Box 9502, 2300 RA, Leiden, The Netherlands
| | - Adriaan P. IJzerman
- Division of Medicinal Chemistry, Leiden/Amsterdam Center for Drug Research, Leiden University, P.O. Box 9502, 2300 RA, Leiden, The Netherlands
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Perlovich GL, Volkova TV, Proshin AN, Dmitriy YS, Bui CT, Petrova LN, Bachurin SO. Synthesis, Pharmacology, Crystal Properties, and Quantitative Solvation Studies from a Drug Transport Perspective for Three New 1,2,4-thiadiazoles. J Pharm Sci 2010; 99:3754-68. [DOI: 10.1002/jps.22143] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
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May LT, Briddon SJ, Hill SJ. Antagonist selective modulation of adenosine A1 and A3 receptor pharmacology by the food dye Brilliant Black BN: evidence for allosteric interactions. Mol Pharmacol 2010; 77:678-86. [PMID: 20086038 DOI: 10.1124/mol.109.063065] [Citation(s) in RCA: 26] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/20/2023] Open
Abstract
Allosteric binding sites on the adenosine receptor family represent potential therapeutic targets for a number of conditions involving metabolic stress. This study has identified Brilliant Black BN as a novel allosteric modulator of the adenosine A(1) and A(3) receptors. In addition to being a food dye and pharmaceutical excipient, Brilliant Black BN is commonly used within calcium mobilization assays to quench extracellular fluorescence. Brilliant Black BN (5-500 microM) had no significant effect on the calcium mobilization stimulated by the nonselective adenosine receptor agonist 5'-(N-ethylcarboxamido)adenosine in Chinese hamster ovary cells stably transfected with the human adenosine A(1) or A(3) receptor. Likewise, calcium mobilization and radioligand binding assays found that Brilliant Black BN (5-500 microM) did not significantly influence the antagonism mediated by 8-cyclopentyl-1,3-dipropylxanthine (100 nM) at the A(1) receptor. In contrast, the affinity of N-[9-chloro-2-(2-furanyl)[1,2,4]-triazolo[1,5-c]quinazolin-5-yl]benzene acetamide (MRS1220) at the A(3) receptor and xanthine amine congener (XAC) and XAC-X-BY630 at the A(1) and A(3) receptors was significantly decreased in the presence of 500 muM Brilliant Black BN. A reduction in XAC potency at the A(1) and A(3) receptor was achieved within 1 min of Brilliant Black BN addition, despite receptors having been pre-equilibrated with antagonist. Dissociation kinetics of the fluorescent XAC derivative, XAC-X-BY630, revealed that the decrease in affinity is probably due to a significant increase in dissociation rate of the antagonist in the presence of Brilliant Black BN. Taken together, these results suggest that Brilliant Black BN can act allosterically to modify ligand affinity at A(1) and A(3) receptors.
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Affiliation(s)
- L T May
- Institute of Cell Signaling, The University of Nottingham Medical School, Queen's Medical Centre, Nottingham NG7 2UH, UK
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Gurung IS, Martinez-Pinna J, Mahaut-Smith MP. Novel consequences of voltage-dependence to G-protein-coupled P2Y1 receptors. Br J Pharmacol 2008; 154:882-9. [PMID: 18414379 DOI: 10.1038/bjp.2008.97] [Citation(s) in RCA: 25] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/22/2023] Open
Abstract
BACKGROUND AND PURPOSE Emerging evidence suggests that activation of G-protein-coupled receptors (GPCRs) can be directly regulated by membrane voltage. However, the physiological and pharmacological relevance of this effect remains unclear. We have further examined this phenomenon for P2Y1 receptors in the non-excitable megakaryocyte using a range of agonists and antagonists. EXPERIMENTAL APPROACH Simultaneous whole-cell patch clamp and fura-2 fluorescence recordings of rat megakaryocytes, which lack voltage-gated Ca2+ influx, were used to examine the voltage-dependence of P2Y1 receptor-evoked IP3-dependent Ca2+ mobilization. RESULTS Depolarization transiently and repeatedly enhanced P2Y1 receptor-evoked Ca2+ mobilization across a wide concentration range of both weak, partial and full, potent agonists. Moreover, the amplitude of the depolarization-evoked [Ca2+]i increase displayed an inverse relationship with agonist concentration, such that the greatest potentiating effect of voltage was observed at near-threshold levels of agonist. Unexpectedly, depolarization also stimulated an [Ca2+]i increase in the absence of agonist during exposure to the competitive antagonists A3P5PS and MRS2179, or the allosteric enhancer 2,2'-pyridylisatogen tosylate. A further effect of some antagonists, particularly suramin, was to enhance the depolarization-evoked Ca2+ responses during co-application of an agonist. Of several P2Y1 receptor inhibitors, only SCH202676, which has a proposed allosteric mechanism of action, could block ADP-induced voltage-dependent Ca2+ release. CONCLUSIONS AND IMPLICATIONS The ability of depolarization to potentiate GPCRs at near-threshold agonist concentrations represents a novel mechanism for coincidence detection. Furthermore, the induction and enhancement of voltage-dependent GPCR responses by antagonists has implications for the design of therapeutic compounds.
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Affiliation(s)
- I S Gurung
- Department of Physiology, Development and Neuroscience, University of Cambridge, Cambridge, UK
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Bellina F, Rossi R. Synthesis and biological activity of pyrrole, pyrroline and pyrrolidine derivatives with two aryl groups on adjacent positions. Tetrahedron 2006. [DOI: 10.1016/j.tet.2006.05.024] [Citation(s) in RCA: 531] [Impact Index Per Article: 29.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/24/2022]
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Heitman LH, Mulder-Krieger T, Spanjersberg RF, von Frijtag Drabbe Künzel JK, Dalpiaz A, IJzerman AP. Allosteric modulation, thermodynamics and binding to wild-type and mutant (T277A) adenosine A1 receptors of LUF5831, a novel nonadenosine-like agonist. Br J Pharmacol 2006; 147:533-41. [PMID: 16444290 PMCID: PMC1616979 DOI: 10.1038/sj.bjp.0706655] [Citation(s) in RCA: 26] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022] Open
Abstract
The interaction of a new nonribose ligand (LUF5831) with the human adenosine A1 receptor was investigated in the present study. Radioligand binding experiments were performed in the absence and presence of diverse allosteric modulators on both wild-type (wt) and mutant (T277A) adenosine A1 receptors. Thermodynamic data were obtained by performing these assays at different temperatures. In addition, cyclic adenosine monophosphate (cAMP) assays were performed. The presence of allosteric modulators had diverse effects on the affinity of LUF5831, N6-cyclopentyladenosine (CPA), a full agonist, and 8-cyclopentyl-1,3-dipropylxanthine (DPCPX), an inverse agonist/antagonist, for the adenosine A1 receptor. PD81,723, for example, increased the affinity of CPA, while the affinity of LUF5831 was decreased. However, the affinity of DPCPX was decreased even more. In addition, LUF5831 was shown to have an affinity for the mutant (T277A) adenosine A1 receptor (Ki=122+/-22 nM), whereas CPA's affinity was negligible. The results of temperature-dependent binding assays showed that the binding of LUF5831 was entropy driven, in between the behaviour of CPA binding to the high- and low-affinity states of the receptor, respectively. The inhibition of the forskolin-induced production of cAMP through activation of the wt adenosine A1 receptor showed that LUF5831 had a submaximal effect (37+/-1%) in comparison to CPA (66+/-5%). On the mutant receptor, however, neither CPA nor LUF5831 inhibited cAMP production. This study indicates that the nonribose ligand, LUF5831, is a partial agonist for the adenosine A1 receptor.
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Affiliation(s)
- Laura H Heitman
- Division of Medicinal Chemistry, Leiden/Amsterdam Center for Drug Research, Leiden University, PO Box 9502, 2300 RA Leiden, The Netherlands
| | - Thea Mulder-Krieger
- Division of Medicinal Chemistry, Leiden/Amsterdam Center for Drug Research, Leiden University, PO Box 9502, 2300 RA Leiden, The Netherlands
| | - Ronald F Spanjersberg
- Division of Medicinal Chemistry, Leiden/Amsterdam Center for Drug Research, Leiden University, PO Box 9502, 2300 RA Leiden, The Netherlands
| | | | - Alessandro Dalpiaz
- Department of Pharmaceutical Chemistry, Ferrara University, Via Fossato di Mortara 19, Ferrara I-44100, Italy
| | - Adriaan P IJzerman
- Division of Medicinal Chemistry, Leiden/Amsterdam Center for Drug Research, Leiden University, PO Box 9502, 2300 RA Leiden, The Netherlands
- Author for correspondence:
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Lewandowicz AM, Vepsäläinen J, Laitinen JT. The 'allosteric modulator' SCH-202676 disrupts G protein-coupled receptor function via sulphydryl-sensitive mechanisms. Br J Pharmacol 2006; 147:422-9. [PMID: 16402041 PMCID: PMC1616996 DOI: 10.1038/sj.bjp.0706624] [Citation(s) in RCA: 22] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/08/2022] Open
Abstract
1. Previous studies suggest that the thiadiazole compound SCH-202676 (N-(2,3-diphenyl-1,2,4-thiadiazol-5-(2H)-ylidene)methanamine) acts as an allosteric modulator of a variety of structurally distinct G protein-coupled receptors (GPCRs). It was postulated that SCH-202676 would directly bind a structural motif in the receptor molecule common to divergent members of the GPCR family. The molecular mechanisms of such a promiscuous action, however, remain obscure. 2. To clarify the mechanism of SCH-202676 action, we used the functional approach of [35S]GTPgammaS autoradiography with rat brain cryostat sections together with classical membrane [35S]GTPgammaS binding assays to evaluate how the thiadiazole affects G protein activity mediated by various receptors linked to the Gi-family of G proteins. 3. We found that in the absence of dithiotreitol (DTT), SCH-202676 (10(-7)-10(-5) M) elicits nonspecific effects in the [35S]GTPgammaS-based G protein activation assays, thereby severely compromising interpretations on the compounds ability to allosterically inhibit receptor-mediated G protein activity. Such a nonspecific behaviour was fully reversed upon addition of DTT (1 mM), revealing thiol-based mechanism of action. 4. In routine incubations containing DTT, SCH-202676 had no effect on receptor-driven G protein activity, as assessed for adenosine A1, alpha2-adrenergic, cannabinoid CB1, lysophosphatidic acid LPA1, muscarinic M2/M4, purinergic P2Y12 or sphingosine 1-phosphate receptors, suggesting that the thiadiazole does not act as an allosteric modulator of GPCR function. 5. 1H NMR analysis indicated that SCH-202676 underwent structural changes after incubation with the reducing agent DTT or with brain tissue. 6. We conclude that SCH-202676 modulates GPCRs via thiol modification rather than via true allosteric mechanisms.
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Affiliation(s)
- Anna M Lewandowicz
- Department of Physiology, University of Kuopio, POB 1627, FIN-70211 Kuopio, Finland
| | - Jouko Vepsäläinen
- Department of Chemistry, University of Kuopio, POB 1627, FIN-70211 Kuopio, Finland
| | - Jarmo T Laitinen
- Department of Physiology, University of Kuopio, POB 1627, FIN-70211 Kuopio, Finland
- Author for correspondence:
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16
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Castro A, Castaño T, Encinas A, Porcal W, Gil C. Advances in the synthesis and recent therapeutic applications of 1,2,4-thiadiazole heterocycles. Bioorg Med Chem 2006; 14:1644-52. [PMID: 16249092 DOI: 10.1016/j.bmc.2005.10.012] [Citation(s) in RCA: 84] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/09/2005] [Revised: 10/03/2005] [Accepted: 10/06/2005] [Indexed: 10/25/2022]
Abstract
Chemical properties of 1,2,4-thiadiazole have been reviewed in the last few years. However, the usefulness of 1,2,4-thiadiazole as a privileged system in medicinal chemistry has prompted the advances on the therapeutic potential of this system. This review provides a brief summary of the medicinal chemistry of 1,2,4-thiadiazole system and highlights some examples of 1,2,4-thiadiazole-containing drug substances in the current literature. A survey of representative literature procedures for the preparation of 1,2,4-thiadiazole is presented in sections by generalized synthetic methods.
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Affiliation(s)
- Ana Castro
- Instituto de Química Médica (CSIC), Juan de la Cierva 3, Madrid, Spain
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17
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Klaasse EC, van den Hout G, Roerink SF, de Grip WJ, Ijzerman AP, Beukers MW. Allosteric modulators affect the internalization of human adenosine A1 receptors. Eur J Pharmacol 2005; 522:1-8. [PMID: 16214128 DOI: 10.1016/j.ejphar.2005.08.052] [Citation(s) in RCA: 14] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/11/2005] [Accepted: 08/10/2005] [Indexed: 10/25/2022]
Abstract
To study the effect of allosteric modulators on the internalization of human adenosine A(1) receptors, the receptor was equipped with a C-terminal yellow fluorescent protein tag. The introduction of this tag did not affect the radioligand binding properties of the receptor. CHO cells stably expressing this receptor were subjected during 16 h to varying concentrations of the agonist N(6)-cyclopentyladenosine (CPA) in the absence or presence of 10 microM of the allosteric enhancer PD 81,723 ((2-amino-4,5-dimethyl-3-thienyl)-[3-(trifluoromethyl)phenyl]methanone) or the allosteric inhibitor SCH-202676 (N-(2,3-diphenyl-1,2,4-thiadiazol-5(2H)-ylidene)methanamine). CPA itself was able to internalize 25% and 40% of the receptors at a concentration of 400 nM or 4 muM, respectively. Addition of either PD 81,723 or SCH-202676 alone had no effect on internalization. However, with PD 81,723 a slight amount of internalization was obtained already at 40 nM of CPA and at 400 nM CPA 59% of the receptors internalized. SCH-202676 on the other hand effectively prevented CPA-induced internalization of the receptor.
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Affiliation(s)
- Elisabeth C Klaasse
- Department of Medicinal Chemistry, Leiden/Amsterdam Center for Drug Research, Leiden University, The Netherlands
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18
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Childers SR, Li X, Xiao R, Eisenach JC. Allosteric modulation of adenosine A1 receptor coupling to G-proteins in brain. J Neurochem 2005; 93:715-23. [PMID: 15836630 DOI: 10.1111/j.1471-4159.2005.03044.x] [Citation(s) in RCA: 33] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
2-Amino-4,5,6,7-tetrahydrobenzo(beta)thiophen-3-yl 4-chlorophenylmethanone (T62) is a member of a group of allosteric modulators of adenosine A1 receptors tested in animal models of neuropathic pain to increase the efficacy of adenosine. To determine its mechanisms at the level of receptor-G-protein activation, the present studies examined the effect of T62 on A1-stimulated [35S]guanosine-5'-O-(gamma-thio)-triphosphate ([35S]GTPgammaS) binding in brain membranes, and by [35S]GTPgammaS autoradiography using the A1 agonist, phenylisopropyladenosine (PIA), to activate G-proteins. In hippocampal membranes, T62 increased both basal and PIA-stimulated [35S]GTPgammaS binding. The effect of T62 was non-competitive in nature, since it increased the maximal effect of PIA, with no effect on agonist potency. GTPgammaS saturation analysis showed that T62 increased the number of G-proteins activated by agonist but had no effect on the affinity of activated G-proteins for GTPgammaS. [35S]GTPgammaS autoradiography showed that the neuroanatomical localization of T62-stimulated [35S]GTPgammaS binding was identical to that of PIA-stimulated activity. The increase in PIA-stimulated activity by T62 varied between brain regions, with areas of lower A1 activation producing the largest percent modulation by T62. These results suggest a mechanism of allosteric modulators to increase the number of activated G-proteins per receptor, and provide a neuroanatomical basis for understanding potential therapeutic effects of such drugs.
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Affiliation(s)
- Steven R Childers
- Department of Physiology/Pharmacology, Wake Forest University School of Medicine, Winston-Salem, North Carolina 27157, USA.
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19
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Gao ZG, Kim SK, Ijzerman AP, Jacobson KA. Allosteric modulation of the adenosine family of receptors. Mini Rev Med Chem 2005; 5:545-53. [PMID: 15974932 PMCID: PMC3431557 DOI: 10.2174/1389557054023242] [Citation(s) in RCA: 62] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
Allosteric modulators for adenosine receptors (ARs) are of an increasing interest and may have potential therapeutic advantage over orthosteric ligands. Benzoylthiophene derivatives (including PD 81,723), 2-aminothiazolium salts, and related allosteric modulators of the A(1) AR have been studied. The benzoylthiophene derivatives were demonstrated to be selective enhancers for the A(1) AR, with little or no effect on other subtypes of ARs. Allosteric modulation of the A(2A) AR has also been reported. A(3) allosteric enhancers may be predicted to be useful against ischemic conditions. We have recently characterized two classes of A(3) AR allosteric modulators: 3-(2-pyridinyl)isoquinolines (e.g. VUF5455) and 1H-imidazo-[4,5-c]quinolin-4-amines (e.g. DU124183), which selectively decreased the agonist dissociation rate at the human A(3)AR but not at A(1) and A(2A) ARs. DU124183 left-shifted the agonist conc.-response curve for inhibition of forskolin-stimulated cAMP accumulation in intact cells expressing the human A(3)AR with up to 30% potentiation of the maximal efficacy. The increased potency of A(3) agonists was evident only in the presence of an A(3) antagonist, since VUF5455 and DU124183 also antagonized, i.e. displaced binding at the orthosteric site, with K(i) values of 1.68 and 0.82 microM, respectively. A(3)AR mutagenesis studies implicated F182(5.43) and N274(7.45) in the action of the enhancers and was interpreted using a rhodopsin-based A(3)AR molecular model, suggesting multiple binding modes. Amiloride analogues, SCH-202676 (N-(2,3-diphenyl-1,2,4-thiadiazol-5(2H)-ylidene)methanamine), and sodium ions were demonstrated to be common allosteric modulators for at least three subtypes (A(1), A(2A), and A(3)) of ARs.
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MESH Headings
- Animals
- Humans
- Models, Molecular
- Mutagenesis
- Receptor, Adenosine A1/chemistry
- Receptor, Adenosine A1/drug effects
- Receptor, Adenosine A2A/chemistry
- Receptor, Adenosine A2A/drug effects
- Receptor, Adenosine A2B/chemistry
- Receptor, Adenosine A2B/drug effects
- Receptors, Purinergic P1/chemistry
- Receptors, Purinergic P1/drug effects
- Receptors, Purinergic P1/genetics
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Affiliation(s)
- Zhan-Guo Gao
- Molecular Recognition Section, Laboratory of Bioorganic Chemistry, NIDDK, National Inst. of Health, Bethesda, Maryland 20892-0810, USA.
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Gao ZG, Mamedova L, Tchilibon S, Gross AS, Jacobson KA. 2,2'-Pyridylisatogen tosylate antagonizes P2Y1 receptor signaling without affecting nucleotide binding. Biochem Pharmacol 2004; 68:231-7. [PMID: 15193995 PMCID: PMC4372108 DOI: 10.1016/j.bcp.2004.02.039] [Citation(s) in RCA: 24] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/07/2004] [Accepted: 02/17/2004] [Indexed: 12/01/2022]
Abstract
The effect of 2,2'-pyridylisatogen tosylate (PIT) on the human P2Y(1) receptor and on other recombinant P2Y receptors has been studied. We first examined the modulation by PIT of the agonist-induced accumulation of inositol phosphates. PIT blocked 2-methylthio-ADP (2-MeSADP)-induced accumulation of inositol phosphates in 1321N1 astrocytoma cells stably expressing human P2Y(1) receptors in a non-competitive and concentration-dependent manner. The IC(50) for reduction of the maximal agonist effect was 0.14microM. In contrast, MRS2179, a competitive P2Y(1) receptor antagonist, parallel-shifted the agonist concentration-response curve to the right. PIT also concentration-dependently blocked the P2Y(1) receptor signaling induced by the endogenous agonists, ADP and ATP. A simple structural analogue of PIT was synthesized and found to be inactive as a P2Y(1) receptor antagonist, suggesting that the nitroxyl group of PIT is a necessary structural component for P2Y(1) receptor antagonism. We next examined the possible modulation of the binding of the newly available antagonist radioligand for the P2Y(1) receptor, [3H] MRS2279. It was found that PIT (0.01-10microM) did not inhibit [3H] MRS2279 binding to the human P2Y(1) receptor. PIT (10microM) had no effect on the competition for [3H] MRS2279 binding by agonists, ADP and ATP, suggesting that its antagonism of the P2Y(1) receptor may be allosteric. PIT had no significant effect on agonist activation of other P2Y receptors, including P2Y(2), P2Y(4), P2Y(6), P2Y(11) and P2Y(12) receptors. Thus, PIT selectively and non-competitively blocked P2Y(1) receptor signaling without affecting nucleotide binding.
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Affiliation(s)
- Zhan-Guo Gao
- Molecular Recognition Section, Laboratory of Bioorganic Chemistry, National Institute of Diabetes and Digestive and Kidney Diseases, National Institutes of Health, Bethesda, MD 20892-0810, USA
| | - Liaman Mamedova
- Molecular Recognition Section, Laboratory of Bioorganic Chemistry, National Institute of Diabetes and Digestive and Kidney Diseases, National Institutes of Health, Bethesda, MD 20892-0810, USA
| | - Susanna Tchilibon
- Molecular Recognition Section, Laboratory of Bioorganic Chemistry, National Institute of Diabetes and Digestive and Kidney Diseases, National Institutes of Health, Bethesda, MD 20892-0810, USA
| | - Ariel S. Gross
- Molecular Recognition Section, Laboratory of Bioorganic Chemistry, National Institute of Diabetes and Digestive and Kidney Diseases, National Institutes of Health, Bethesda, MD 20892-0810, USA
| | - Kenneth A. Jacobson
- Molecular Recognition Section, Laboratory of Bioorganic Chemistry, National Institute of Diabetes and Digestive and Kidney Diseases, National Institutes of Health, Bethesda, MD 20892-0810, USA
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