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Woo SH, Trinh TN. P2 Receptors in Cardiac Myocyte Pathophysiology and Mechanotransduction. Int J Mol Sci 2020; 22:ijms22010251. [PMID: 33383710 PMCID: PMC7794727 DOI: 10.3390/ijms22010251] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/04/2020] [Revised: 12/22/2020] [Accepted: 12/22/2020] [Indexed: 12/30/2022] Open
Abstract
ATP is a major energy source in the mammalian cells, but it is an extracellular chemical messenger acting on P2 purinergic receptors. A line of evidence has shown that ATP is released from many different types of cells including neurons, endothelial cells, and muscle cells. In this review, we described the distribution of P2 receptor subtypes in the cardiac cells and their physiological and pathological roles in the heart. So far, the effects of external application of ATP or its analogues, and those of UTP on cardiac contractility and rhythm have been reported. In addition, specific genetic alterations and pharmacological agonists and antagonists have been adopted to discover specific roles of P2 receptor subtypes including P2X4-, P2X7-, P2Y2- and P2Y6-receptors in cardiac cells under physiological and pathological conditions. Accumulated data suggest that P2X4 receptors may play a beneficial role in cardiac muscle function, and that P2Y2- and P2Y6-receptors can induce cardiac fibrosis. Recent evidence further demonstrates P2Y1 receptor and P2X4 receptor as important mechanical signaling molecules to alter membrane potential and Ca2+ signaling in atrial myocytes and their uneven expression profile between right and left atrium.
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Molecular pharmacology of P2Y receptor subtypes. Biochem Pharmacol 2020; 187:114361. [PMID: 33309519 DOI: 10.1016/j.bcp.2020.114361] [Citation(s) in RCA: 41] [Impact Index Per Article: 10.3] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/19/2020] [Revised: 12/06/2020] [Accepted: 12/07/2020] [Indexed: 02/06/2023]
Abstract
Professor Geoffrey Burnstock proposed the concept of purinergic signaling via P1 and P2 receptors. P2Y receptors are G-protein-coupled receptors (GPCRs) for extracellular adenine and uracil nucleotides. Eight mammalian P2Y receptor subtypes have been identified. They are divided into two subgroups (P2Y1, P2Y2, P2Y4, P2Y6, and P2Y11) and (P2Y12, P2Y13, and P2Y14). P2Y receptors are found in almost all cells and mediate responses in physiology and pathophysiology including pain and inflammation. The antagonism of platelet P2Y12 receptors by cangrelor, ticagrelor or active metabolites of the thienopyridine compounds ticlopidine, clopidogrel and prasugrel reduces the ADP-induced platelet aggregation in patients with thrombotic complications of vascular diseases. The nucleotide agonist diquafosol acting at P2Y2 receptors is used for the treatment of the dry eye syndrome. Structural information obtained by crystallography of the human P2Y1 and P2Y12 receptor proteins, site-directed mutagenesis and molecular modeling will facilitate the rational design of novel selective drugs.
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von Kügelgen I. Pharmacology of P2Y receptors. Brain Res Bull 2019; 151:12-24. [PMID: 30922852 DOI: 10.1016/j.brainresbull.2019.03.010] [Citation(s) in RCA: 57] [Impact Index Per Article: 11.4] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/15/2018] [Revised: 03/04/2019] [Accepted: 03/17/2019] [Indexed: 01/17/2023]
Abstract
P2Y receptors are G-protein-coupled receptors (GPCRs) for extracellular nucleotides. There are eight mammalian P2Y receptor subtypes divided into two subgroups (P2Y1, P2Y2, P2Y4, P2Y6, and P2Y11) and (P2Y12, P2Y13, and P2Y14). The P2Y receptors are expressed in various cell types and play important roles in physiology and pathophysiology including inflammatory responses and neuropathic pain. The antagonism of P2Y12 receptors is used in pharmacotherapy for the prevention and therapy of cardiovascular events. The nucleoside analogue ticagrelor and active metabolites of the thienopyridine compounds ticlopidine, clopidogrel and prasugrel inhibit platelet P2Y12 receptors and reduce thereby platelet aggregation. The P2Y2 receptor agonist diquafosol is used for the treatment of the dry eye syndrome. The P2Y receptor subtypes differ in their amino acid sequences, their pharmacological profiles and their signaling transduction pathways. Recently, selective receptor ligands have been developed for all subtypes. The published crystal structures of the human P2Y1 and P2Y12 receptors as well as receptor models will facilitate the development of novel drugs for pharmacotherapy.
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Affiliation(s)
- Ivar von Kügelgen
- Department of Pharmacology and Toxicology, Pharma Center, University of Bonn, D-53127, Bonn, Germany.
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P2Y 11 Receptors: Properties, Distribution and Functions. ADVANCES IN EXPERIMENTAL MEDICINE AND BIOLOGY 2018; 1051:107-122. [PMID: 29134605 DOI: 10.1007/5584_2017_89] [Citation(s) in RCA: 26] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Key Words] [Subscribe] [Scholar Register] [Indexed: 01/16/2023]
Abstract
The P2Y11 receptor is a G protein-coupled receptor that is stimulated by endogenous purine nucleotides, particularly ATP. Amongst P2Y receptors it has several unique properties; (1) it is the only human P2Y receptor gene that contains an intron in the coding sequence; (2) the gene does not appear to be present in the rodent genome; (3) it couples to stimulation of both phospholipase C and adenylyl cyclase. Its absence in mice and rats, along with a limited range of selective pharmacological tools, has hampered the development of our knowledge and understanding of its properties and functions. Nonetheless, through a combination of careful use of the available tools, suppression of receptor expression using siRNA and genetic screening for SNPs, possible functions of native P2Y11 receptors have been identified in a variety of human cells and tissues. Many are in blood cells involved in inflammatory responses, consistent with extracellular ATP being a damage-associated signalling molecule in the immune system. Thus proposed potential therapeutic applications relate, in the main, to modulation of acute and chronic inflammatory responses.
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Dreisig K, Kornum BR. A critical look at the function of the P2Y11 receptor. Purinergic Signal 2016; 12:427-37. [PMID: 27246167 DOI: 10.1007/s11302-016-9514-7] [Citation(s) in RCA: 58] [Impact Index Per Article: 7.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/03/2015] [Accepted: 04/17/2016] [Indexed: 11/30/2022] Open
Abstract
The P2Y11 receptor is a member of the purinergic receptor family. It has been overlooked, somewhat due to the lack of a P2ry11 gene orthologue in the murine genome, which prevents the generation of knockout mice, which have been so helpful for defining the roles of other P2Y receptors. Furthermore, some of the studies reported to date have methodological shortcomings, making it difficult to determine the function of P2Y11 with certainty. In this review, we discuss the lack of a murine "P2Y11-like receptor" and highlight the limitations of the currently available methods used to investigate the P2Y11 receptor. These methods include protein recognition with antibodies that show very little specificity, gene expression studies that completely overlook the existence of a fusion transcript between the adjacent PPAN gene and P2RY11, and agonists/antagonists reported to be specific for the P2Y11 receptor but which have not been tested for activity on numerous other adenosine 5'-triphosphate (ATP)-binding receptors. We suggest a set of criteria for evaluating whether a dataset describes effects mediated by the P2Y11 receptor. Following these criteria, we conclude that the current evidence suggests a role for P2Y11 in immune activation with cell type-specific effects.
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Affiliation(s)
- Karin Dreisig
- Molecular Sleep Laboratory, Department of Clinical Biochemistry, Rigshospitalet, Glostrup, Denmark
| | - Birgitte Rahbek Kornum
- Molecular Sleep Laboratory, Department of Clinical Biochemistry, Rigshospitalet, Glostrup, Denmark.
- Danish Center for Sleep Medicine, Department of Clinical Neurophysiology, Rigshospitalet, Glostrup, Denmark.
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von Kügelgen I, Hoffmann K. Pharmacology and structure of P2Y receptors. Neuropharmacology 2015; 104:50-61. [PMID: 26519900 DOI: 10.1016/j.neuropharm.2015.10.030] [Citation(s) in RCA: 163] [Impact Index Per Article: 18.1] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/17/2015] [Revised: 10/22/2015] [Accepted: 10/23/2015] [Indexed: 01/30/2023]
Abstract
P2Y receptors are G-protein-coupled receptors (GPCRs) for extracellular nucleotides. There are eight mammalian P2Y receptor subtypes (P2Y1, P2Y2, P2Y4, P2Y6, P2Y11, P2Y12, P2Y13, and P2Y14). P2Y receptors are widely expressed and play important roles in physiology and pathophysiology. One important example is the ADP-induced platelet aggregation mediated by P2Y1 and P2Y12 receptors. Active metabolites of the thienopyridine compounds ticlopidine, clopidogrel and prasugrel as well as the nucleoside analogue ticagrelor block P2Y12 receptors and thereby platelet aggregation. These drugs are used for the prevention and therapy of cardiovascular events. Moreover, P2Y receptors play important roles in the nervous system. Adenine nucleotides modulate neuronal activity and neuronal fibre outgrowth by activation of P2Y1 receptors and control migration of microglia by P2Y12 receptors. UDP stimulates microglial phagocytosis through activation of P2Y6 receptors. There is evidence for a role for P2Y2 receptors in Alzheimer's disease pathology. The P2Y receptor subtypes are highly diverse in both their amino acid sequences and their pharmacological profiles. Selective receptor ligands have been developed for the pharmacological characterization of the receptor subtypes. The recently published three-dimensional crystal structures of the human P2Y1 and P2Y12 receptors will facilitate the development of therapeutic agents that selectively target P2Y receptors. This article is part of the Special Issue entitled 'Purines in Neurodegeneration and Neuroregeneration'.
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Affiliation(s)
- Ivar von Kügelgen
- Department of Pharmacology and Toxicology, Pharma Center, University of Bonn, D-53127 Bonn, Germany.
| | - Kristina Hoffmann
- Department of Pharmacology and Toxicology, Pharma Center, University of Bonn, D-53127 Bonn, Germany
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Langfelder A, Okonji E, Deca D, Wei WC, Glitsch MD. Extracellular acidosis impairs P2Y receptor-mediated Ca(2+) signalling and migration of microglia. Cell Calcium 2015; 57:247-56. [PMID: 25623949 DOI: 10.1016/j.ceca.2015.01.004] [Citation(s) in RCA: 22] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/11/2014] [Revised: 12/31/2014] [Accepted: 01/02/2015] [Indexed: 02/07/2023]
Abstract
Microglia are the resident macrophage and immune cell of the brain and are critically involved in combating disease and assaults on the brain. Virtually all brain pathologies are accompanied by acidosis of the interstitial fluid, meaning that microglia are exposed to an acidic environment. However, little is known about how extracellular acidosis impacts on microglial function. The activity of microglia is tightly controlled by 'on' and 'off' signals, the presence or absence of which results in generation of distinct phenotypes in microglia. Activation of G protein coupled purinergic (P2Y) receptors triggers a number of distinct behaviours in microglia, including activation, migration, and phagocytosis. Using pharmacological tools and fluorescence imaging of the murine cerebellar microglia cell line C8B4, we show that extracellular acidosis interferes with P2Y receptor-mediated Ca(2+) signalling in these cells. Distinct P2Y receptors give rise to signature intracellular Ca(2+) signals, and Ca(2+) release from stores and Ca(2+) influx are differentially affected by acidotic conditions: Ca(2+) release is virtually unaffected, whereas Ca(2+) influx, mediated at least in part by store-operated Ca(2+) channels, is profoundly inhibited. Furthermore, P2Y1 and P2Y6-mediated stimulation of migration is inhibited under conditions of extracellular acidosis, whereas basal migration independent of P2Y receptor activation is not. Taken together, our results demonstrate that an acidic microenvironment impacts on P2Y receptor-mediated Ca(2+) signalling, thereby influencing microglial responses and responsiveness to extracellular signals. This may result in altered behaviour of microglia under pathological conditions compared with microglial responses in healthy tissue.
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Affiliation(s)
- Antonia Langfelder
- Department of Physiology, Anatomy and Genetics, University of Oxford, Parks Road, Oxford OX1 3PT, UK
| | - Emeka Okonji
- Department of Physiology, Anatomy and Genetics, University of Oxford, Parks Road, Oxford OX1 3PT, UK
| | - Diana Deca
- Department of Physiology, Anatomy and Genetics, University of Oxford, Parks Road, Oxford OX1 3PT, UK
| | - Wei-Chun Wei
- Department of Physiology, Anatomy and Genetics, University of Oxford, Parks Road, Oxford OX1 3PT, UK
| | - Maike D Glitsch
- Department of Physiology, Anatomy and Genetics, University of Oxford, Parks Road, Oxford OX1 3PT, UK.
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Burnstock G, Evans LC, Bailey MA. Purinergic signalling in the kidney in health and disease. Purinergic Signal 2014; 10:71-101. [PMID: 24265071 PMCID: PMC3944043 DOI: 10.1007/s11302-013-9400-5] [Citation(s) in RCA: 73] [Impact Index Per Article: 7.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/16/2013] [Accepted: 10/24/2013] [Indexed: 12/21/2022] Open
Abstract
The involvement of purinergic signalling in kidney physiology and pathophysiology is rapidly gaining recognition and this is a comprehensive review of early and recent publications in the field. Purinergic signalling involvement is described in several important intrarenal regulatory mechanisms, including tuboglomerular feedback, the autoregulatory response of the glomerular and extraglomerular microcirculation and the control of renin release. Furthermore, purinergic signalling influences water and electrolyte transport in all segments of the renal tubule. Reports about purine- and pyrimidine-mediated actions in diseases of the kidney, including polycystic kidney disease, nephritis, diabetes, hypertension and nephrotoxicant injury are covered and possible purinergic therapeutic strategies discussed.
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Affiliation(s)
- Geoffrey Burnstock
- Autonomic Neuroscience Centre, University College Medical School, Rowland Hill Street, London, NW3 2PF, UK,
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Molecular pharmacology, physiology, and structure of the P2Y receptors. ADVANCES IN PHARMACOLOGY (SAN DIEGO, CALIF.) 2011; 61:373-415. [PMID: 21586365 DOI: 10.1016/b978-0-12-385526-8.00012-6] [Citation(s) in RCA: 101] [Impact Index Per Article: 7.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/20/2022]
Abstract
The P2Y receptors are a widely expressed group of eight nucleotide-activated G protein-coupled receptors (GPCRs). The P2Y(1)(ADP), P2Y(2)(ATP/UTP), P2Y(4)(UTP), P2Y(6)(UDP), and P2Y(11)(ATP) receptors activate G(q) and therefore robustly promote inositol lipid signaling responses. The P2Y(12)(ADP), P2Y(13)(ADP), and P2Y(14)(UDP/UDP-glucose) receptors activate G(i) leading to inhibition of adenylyl cyclase and to Gβγ-mediated activation of a range of effector proteins including phosphoinositide 3-kinase-γ, inward rectifying K(+) (GIRK) channels, phospholipase C-β2 and -β3, and G protein-receptor kinases 2 and 3. A broad range of physiological responses occur downstream of activation of these receptors ranging from Cl(-) secretion by epithelia to aggregation of platelets to neurotransmission. Useful structural models of the P2Y receptors have evolved from extensive genetic analyses coupled with molecular modeling based on three-dimensional structures obtained for rhodopsin and several other GPCRs. Selective ligands have been synthesized for most of the P2Y receptors with the most prominent successes attained with highly selective agonist and antagonist molecules for the ADP-activated P2Y(1) and P2Y(12) receptors. The widely prescribed drug, clopidogrel, which results in irreversible blockade of the platelet P2Y(12) receptor, is the most important therapeutic agent that targets a P2Y receptor.
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Glatt S, Halbauer D, Heindl S, Wernitznig A, Kozina D, Su KC, Puri C, Garin-Chesa P, Sommergruber W. hGPR87 contributes to viability of human tumor cells. Int J Cancer 2008; 122:2008-16. [PMID: 18183596 DOI: 10.1002/ijc.23349] [Citation(s) in RCA: 34] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/13/2023]
Abstract
Emerging in vitro and in vivo data underline the crucial role of G-protein-coupled receptors (GPCRs) in tumorigenesis. Here, we report the contribution of hGPR87, a predicted member of the P2Y subfamily of GPCRs, to proliferation and survival of human tumor cell lines. hGPR87 mRNA transcript was found to be preferentially overexpressed in squamous cell carcinomas (SCCs) of different locations and in their lymph node metastases. Up-regulation of both, transcript and protein, was detected in samples of SCC of the lung, cervix, skin and head and neck (pharynx, larynx and epiglottis). In addition to the expression of hGPR87 in tumors which originate from stratified epithelia, we identified other hGPR87-positive tumor types including subsets of large cell and adenocarcinomas of the lung and transitional cell carcinomas of the urinary bladder. Loss of function studies using siRNA in human cancer cell lines lead to antiproliferative effects and induction of apoptosis. Like other known P2Y receptors, hGPR87 was found to be mainly located on the cell surface. The overexpression of hGPR87 preferentially in SCCs together with our functional data suggests a common molecular mechanism for SCC tumorigenesis and may provide a novel intervention site for mechanism-based antitumor therapies.
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Affiliation(s)
- Sebastian Glatt
- Boehringer-Ingelheim Austria GmbH, Dr. Boehringer-Gassse 5-11, Vienna, Austria
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11
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Vallon V. P2 receptors in the regulation of renal transport mechanisms. Am J Physiol Renal Physiol 2007; 294:F10-27. [PMID: 17977905 DOI: 10.1152/ajprenal.00432.2007] [Citation(s) in RCA: 92] [Impact Index Per Article: 5.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/16/2022] Open
Abstract
Extracellular nucleotides (e.g., ATP) regulate physiological and pathophysiological processes through activation of nucleotide P2 receptors in the plasma membrane. Examples include such diverse processes as communication from taste buds to gustatory nerves, platelet aggregation, nociception, or neutrophil chemotaxis. Over approximately the last 15 years, evidence has also accumulated that cells in renal epithelia release nucleotides in response to physiological stimuli and that these nucleotides act in a paracrine and autocrine way to activate P2 receptors and play a significant role in the regulation of transport mechanisms and cell volume regulation. This review discusses potential stimuli and mechanisms involved in nucleotide release in renal epithelia and summarizes the available data on the expression and function of nucleotide P2 receptors along the native mammalian tubular and collecting duct system. Using established agonist profiles for P2 receptor subtypes, significant insights have been gained particularly into a potential role for P2Y(2)-like receptors in the regulation of transport mechanisms in the collecting duct. Due to the lack of receptor subtype-specific antagonists, however, the in vivo relevance of P2 receptor subtypes is unclear. Studies in gene knockout mice provided first insights including an antihypertensive activity of P2Y(2) receptors that is linked to an inhibitory influence on renal Na(+) and water reabsorption. We are only beginning to unravel the important roles of extracellular nucleotides and P2 receptors in the regulation of the diverse transport mechanisms of the kidney.
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Affiliation(s)
- Volker Vallon
- Department of Medicine, University of California and Veterans Affairs San Diego Healthcare System, 3350 La Jolla Village Dr., San Diego, CA 92161., USA.
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Devader C, Drew CM, Geach TJ, Tabler J, Townsend-Nicholson A, Dale L. A novel nucleotide receptor in Xenopus activates the cAMP second messenger pathway. FEBS Lett 2007; 581:5332-6. [PMID: 17977530 DOI: 10.1016/j.febslet.2007.10.024] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/10/2007] [Accepted: 10/12/2007] [Indexed: 10/22/2022]
Abstract
We describe a Xenopus P2Y receptor that shares only weak homology with members of the mammalian P2Y family, being most similar to human P2Y(11). When activated by nucleotide analogs, it stimulates both calcium and cAMP mobilization pathways, a feature unique, among mammalian P2Y receptors, to P2Y(11). Activity can be blocked by compounds known to act as antagonists of mammalian P2Y(11). Genomic synteny between Xenopus and mammals suggests that the novel gene is a true ortholog of P2Y(11). Xenopus P2Y(11) is transcribed during embryonic development, beginning at gastrulation, and is enriched in the developing nervous system.
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Affiliation(s)
- Christelle Devader
- Department of Anatomy and Developmental Biology, University College London, Gower Street, London WC1E 6BT, UK
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13
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Yamamoto S, Ichishima K, Ehara T. Regulation of extracellular UTP-activated Cl- current by P2Y-PLC-PKC signaling and ATP hydrolysis in mouse ventricular myocytes. J Physiol Sci 2007; 57:85-94. [PMID: 17291397 DOI: 10.2170/physiolsci.rp011406] [Citation(s) in RCA: 15] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/03/2006] [Accepted: 02/08/2007] [Indexed: 11/05/2022]
Abstract
The intracellular signaling pathways responsible for extracellualr uridine-5'-triphosphate (UTPo)-induced chloride (Cl-) currents (I(Cl.UTP)) were studied in mouse ventricular myocytes with the whole-cell clamp technique. UTPo (0.1 to 100 microM) activated a whole-cell current that showed a time-independent activation, a linear current-voltage relationship in symmetrical Cl- solutions, an anion selectivity of Cl- > iodide > aspartate, and an inhibition by a thiazolidinone-derived specific inhibitor (CFTR(inh)-172, 10 microM) of cystic fibrosis transmembrane conductance regulator (CFTR), but not by a disulfonic stilbene derivative (DIDS, 100 microM), these properties matching those of CFTR Cl- channels. The potency order of nucleotides for an activation of the Cl- current was UTP = ATP > uridine-5'-diphosphate (UDP) = ADP. Suramin (100 microM), a P2Y receptor antagonist, strongly inhibited the UTPo -activation of the Cl- current, whereas pyridoxalphosphate-6-azophenyl-2',4'-disulfonic acid (PPADS, 100 microM), another P2Y receptor antagonist, induced little inhibition of I(Cl.UTP). The activation of I(Cl.UTP) was sensitive to protein kinase C (PKC) inhibitor, phospholipase C (PLC) inhibitor, intracellular GDPbetaS (nonhydrolyzable GDP analogue) or anti-Gq/11 antibody. UTPo failed to activate the Cl- current when the cells were dialyzed with nonhydrolyzable ATP analogues (ATPS or AMP-PNP) without ATP, suggesting that ATP hydrolysis is a prerequisite for the current activation. I(Cl.UTP) was persistently activated with a mixture of ATPgammaS + ATP in the pipette, suggesting the involvement of phosphorylation reaction in the current activation process. Our results strongly suggest that I(Cl.UTP) is due to the activation of CFTR Cl- channels through Gq/11-coupled P2Y2 receptor-PLC-PKC signaling and ATP hydrolysis in mouse heart.
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Affiliation(s)
- Shintaro Yamamoto
- Department of Physiology, Saga University Faculty of Medicine, Saga, 849-8501 Japan.
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Abbracchio MP, Burnstock G, Boeynaems JM, Barnard EA, Boyer JL, Kennedy C, Knight GE, Fumagalli M, Gachet C, Jacobson KA, Weisman GA. International Union of Pharmacology LVIII: update on the P2Y G protein-coupled nucleotide receptors: from molecular mechanisms and pathophysiology to therapy. Pharmacol Rev 2006; 58:281-341. [PMID: 16968944 PMCID: PMC3471216 DOI: 10.1124/pr.58.3.3] [Citation(s) in RCA: 987] [Impact Index Per Article: 54.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/31/2022] Open
Abstract
There have been many advances in our knowledge about different aspects of P2Y receptor signaling since the last review published by our International Union of Pharmacology subcommittee. More receptor subtypes have been cloned and characterized and most orphan receptors de-orphanized, so that it is now possible to provide a basis for a future subdivision of P2Y receptor subtypes. More is known about the functional elements of the P2Y receptor molecules and the signaling pathways involved, including interactions with ion channels. There have been substantial developments in the design of selective agonists and antagonists to some of the P2Y receptor subtypes. There are new findings about the mechanisms underlying nucleotide release and ectoenzymatic nucleotide breakdown. Interactions between P2Y receptors and receptors to other signaling molecules have been explored as well as P2Y-mediated control of gene transcription. The distribution and roles of P2Y receptor subtypes in many different cell types are better understood and P2Y receptor-related compounds are being explored for therapeutic purposes. These and other advances are discussed in the present review.
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Affiliation(s)
- Maria P Abbracchio
- Department of Pharmacological Sciences, University of Milan, Milan, Italy
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von Kügelgen I. Pharmacological profiles of cloned mammalian P2Y-receptor subtypes. Pharmacol Ther 2005; 110:415-32. [PMID: 16257449 DOI: 10.1016/j.pharmthera.2005.08.014] [Citation(s) in RCA: 417] [Impact Index Per Article: 21.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/15/2005] [Accepted: 08/23/2005] [Indexed: 11/29/2022]
Abstract
Membrane-bound P2-receptors mediate the actions of extracellular nucleotides in cell-to-cell signalling. P2X-receptors are ligand-gated ion channels, whereas P2Y-receptors belong to the superfamily of G-protein-coupled receptors (GPCRs). So far, the P2Y family is composed out of 8 human subtypes that have been cloned and functionally defined; species orthologues have been found in many vertebrates. P2Y1-, P2Y2-, P2Y4-, P2Y6-, and P2Y11-receptors all couple to stimulation of phospholipase C. The P2Y11-receptor mediates in addition a stimulation of adenylate cyclase. In contrast, activation of the P2Y12-, P2Y13-, and P2Y14-receptors causes an inhibition of adenylate cyclase activity. The expression of P2Y1-receptors is widespread. The receptor is involved in blood platelet aggregation, vasodilatation and neuromodulation. It is activated by ADP and ADP analogues including 2-methylthio-ADP (2-MeSADP). 2'-Deoxy-N6-methyladenosine-3',5'-bisphosphate (MRS2179) and 2-chloro-N6-methyl-(N)-methanocarba-2'-deoxyadenosine 3',5'-bisphosphate (MRS2279) are potent and selective antagonists. P2Y2 transcripts are abundantly distributed. One important example for its functional role is the control of chloride ion fluxes in airway epithelia. The P2Y2-receptor is activated by UTP and ATP and blocked by suramin. The P2Y2-agonist diquafosol is used for the treatment of the dry eye disease. P2Y4-receptors are expressed in the placenta and in epithelia. The human P2Y4-receptor has a strong preference for UTP as agonist, whereas the rat P2Y4-receptor is activated about equally by UTP and ATP. The P2Y4-receptor is not blocked by suramin. The P2Y6-receptor has a widespread distribution including heart, blood vessels, and brain. The receptor prefers UDP as agonist and is selectively blocked by 1,2-di-(4-isothiocyanatophenyl)ethane (MRS2567). The P2Y11-receptor may play a role in the differentiation of immunocytes. The human P2Y11-receptor is activated by ATP as naturally occurring agonist and it is blocked by suramin and reactive blue 2 (RB2). The P2Y12-receptor plays a crucial role in platelet aggregation as well as in inhibition of neuronal cells. It is activated by ADP and very potently by 2-methylthio-ADP. Nucleotide antagonists including N6-(2-methylthioethyl)-2-(3,3,3-trifluoropropylthio)-beta,gamma-dichloromethylene-ATP (=cangrelor; AR-C69931MX), the nucleoside analogue AZD6140, as well as active metabolites of the thienopyridine compounds clopidogrel and prasugrel block the receptor. These P2Y12-antagonists are used in pharmacotherapy to inhibit platelet aggregation. The P2Y13-receptor is expressed in immunocytes and neuronal cells and is again activated by ADP and 2-methylthio-ADP. The 2-chloro-5-nitro pyridoxal-phosphate analogue 6-(2'-chloro-5'-nitro-azophenyl)-pyridoxal-alpha5-phosphate (MRS2211) is a selective antagonist. mRNA encoding for the human P2Y14-receptor is found in many tissues. However, a physiological role of the receptor has not yet been established. UDP-glucose and related analogues act as agonists; antagonists are not known. Finally, UDP has been reported to act on receptors for cysteinyl leukotrienes as an additional agonist--indicating a dual agonist specificity of these receptors.
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Affiliation(s)
- Ivar von Kügelgen
- Department of Pharmacology, University of Bonn, Reuterstrasse 2b, D-53113 Bonn, Germany.
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16
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Guerra L, Favia M, Fanelli T, Calamita G, Svetlo M, Bagorda A, Jacobson KA, Reshkin SJ, Casavola V. Stimulation of Xenopus P2Y1 receptor activates CFTR in A6 cells. Pflugers Arch 2005; 449:66-75. [PMID: 15235914 DOI: 10.1007/s00424-004-1293-2] [Citation(s) in RCA: 17] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/26/2022]
Abstract
Nucleotide binding to purinergic P2Y receptors contributes to the regulation of a variety of physiological functions in renal epithelial cells. Here, we investigate the regulatory mechanism of the P2Y1 receptor agonist 2-methylthioadenosine diphosphate (2-MeSADP) on Cl- transport in A6 cells, a commonly used model of the distal section of the Xenopus laevis nephron. Protein and mRNA expression analysis together with functional measurements demonstrated the basolateral location of the Xenopus P2Y1 receptor. 2-MeSADP increased intracellular [Ca2+] and cAMP and Cl- efflux, responses that were all inhibited by the specific P2Y1 receptor antagonist MRS 2179. Cl- efflux was also inhibited by the cystic fibrosis transmembrane conductance regulator (CFTR) blocker glibenclamide. Inhibition of either protein kinase A (PKA) or the binding between A-kinase-anchoring proteins (AKAPs) and the regulatory PKA RII subunit blocked the 2-MeSADP-induced activation of CFTR, suggesting that PKA mediates P2Y1 receptor regulation of CFTR through one or more AKAPs. Further, the truncation of the PDZ1 domain of the scaffolding protein Na+/H+ exchanger regulatory factor-2 (NHERF-2) inhibited 2-MeSADP-dependent stimulation of Cl- efflux, suggesting the involvement of this scaffolding protein. Activation or inhibition of PKC had no effect per se on basal Cl- efflux but potentiated or reduced the 2-MeSADP-dependent stimulation of Cl- efflux, respectively. These data suggest that the X laevis P2Y1 receptor in A6 cells can increase both cAMP/PKA and Ca2+/PKC intracellular levels and that the PKC pathway is involved in CFTR activation via potentiation of the PKA pathway.
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Affiliation(s)
- L Guerra
- Department of General and Environmental Physiology, University of Bari, Via Amendola 165/A, 70126 Bari, Italy
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17
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Balogh J, Wihlborg AK, Isackson H, Joshi BV, Jacobson KA, Arner A, Erlinge D. Phospholipase C and cAMP-dependent positive inotropic effects of ATP in mouse cardiomyocytes via P2Y11-like receptors. J Mol Cell Cardiol 2005; 39:223-30. [PMID: 15893764 PMCID: PMC3471220 DOI: 10.1016/j.yjmcc.2005.03.007] [Citation(s) in RCA: 53] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 10/07/2004] [Revised: 03/16/2005] [Accepted: 03/17/2005] [Indexed: 11/18/2022]
Abstract
ATP is released as a cotransmitter together with catecholamines from sympathetic nerves. In the heart ATP has been shown to cause a pronounced positive inotropic effect and may also act in synergy with beta-adrenergic agonists to augment cardiomyocyte contractility. The aim of the present study was to investigate the inotropic effects mediated by purinergic P2 receptors using isolated mouse cardiomyocytes. Stable adenine nucleotide analogs were used and the agonist rank order for adenine nucleotide stimulation of the mouse cardiomyocytes was AR-C67085>ATPgammaS>2-MeSATP>>>2-MeSADP=0, that fits the agonist profile of the P2Y11 receptor. ATPgammaS induced a positive inotropic response in single mouse cardiomyocytes. The response was similar to that for the beta1 receptor agonist isoproterenol. The most potent response was obtained using AR-C67085, a P2Y11 receptor agonist. This agonist also potentiated contractions in isolated trabecular preparations. The adenylyl cyclase blocker (SQ22563) and phospholipase C (PLC) blocker (U73122) demonstrated that both pathways were required for the inotropic response of AR-C67085. A cAMP enzyme immunoassay confirmed that AR-C67085 increased cAMP in the cardiomyocytes. These findings are in agreement with the P2Y11 receptor, coupled both to activation of IP3 and cAMP, being a major receptor for ATP induced inotropy. Analyzing cardiomyocytes from desmin deficient mice, Des-/-, with a congenital cardiomyopathy, we found a lower sensitivity to AR-C67085, suggesting a down-regulation of P2Y11 receptor function in heart failure. The prominent action of the P2Y11 receptor in controling cardiomyocyte contractility and possible alterations in its function during cardiomyopathy may suggest this receptor as a potential therapeutic target. It is possible that agonists for the P2Y11 receptor could be used to improve cardiac output in patients with circulatory shock and that P2Y11 receptor antagonist could be beneficial in patients with congestive heart failure (CHF).
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Affiliation(s)
- Johanna Balogh
- Department of Physiological Sciences, Lund University, Lund, Sweden
| | | | - Henrik Isackson
- Department of Physiological Sciences, Lund University, Lund, Sweden
| | | | | | - Anders Arner
- Department of Physiological Sciences, Lund University, Lund, Sweden
| | - David Erlinge
- Department of Cardiology, Lund University, Lund, Sweden
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18
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Cox MA, Gomes B, Palmer K, Du K, Wiekowski M, Wilburn B, Petro M, Chou CC, Desquitado C, Schwarz M, Lunn C, Lundell D, Narula SK, Zavodny PJ, Jenh CH. The pyrimidinergic P2Y6 receptor mediates a novel release of proinflammatory cytokines and chemokines in monocytic cells stimulated with UDP. Biochem Biophys Res Commun 2005; 330:467-73. [PMID: 15796906 DOI: 10.1016/j.bbrc.2005.03.004] [Citation(s) in RCA: 46] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/28/2005] [Indexed: 10/25/2022]
Abstract
The human P2Y6 receptor (hP2Y6) is a member of the G protein-coupled pyrimidinergic P2 receptor family that responds specifically to the extracellular nucleotide uridine diphosphate (UDP). Recently, the hP2Y6 receptor has been reported to mediate monocyte IL-8 production in response to UDP or lipopolysaccharide (LPS), but the role of hP2Y6 in regulating other pro-inflammatory cytokines or mediators is largely unknown. We demonstrate here that UDP specifically induces soluble TNF-alpha and IL-8 production in a promonocytic U937 cell line stably transfected with hP2Y6. However, we did not detect IL-1alpha, IL-1beta, IL-6, IL-10, IL-18, and PGE2 in the conditioned media from the same cell line. These results distinguish UDP/P2Y6 signaling from LPS signaling. Interestingly, UDP induces the production of IL-8, but not TNF-alpha, in human astrocytoma 1321N1 cell lines stably transfected with hP2Y6. Therefore, the immune effect of UDP/P2Y6 signaling on the production of proinflammatory cytokines is selective and dependent on cell types. We further identify that UDP can also induce the production of proinflammatory chemokines MCP-1 and IP-10 in hP2Y6 transfected promonocytic U937 cell lines, but not astrocytoma 1321N1 cell lines stably transfected with hP2Y6. From the Taqman analysis, UDP stimulation significantly upregulates the mRNA levels of IL-8, IP-10, and IL-1beta, but not TNF-alpha. Taken together, these new findings expand the pro-inflammatory biology of UDP mediated by the P2Y6 receptor.
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Affiliation(s)
- Mary Ann Cox
- Department of Inflammation and Infection, Schering-Plough Research Institute, Kenilworth, NJ 07033, USA
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19
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Lechner SG, Dorostkar MM, Mayer M, Edelbauer H, Pankevych H, Boehm S. Autoinhibition of transmitter release from PC12 cells and sympathetic neurons through a P2Y receptor-mediated inhibition of voltage-gated Ca2+ channels. Eur J Neurosci 2005; 20:2917-28. [PMID: 15579146 DOI: 10.1111/j.1460-9568.2004.03760.x] [Citation(s) in RCA: 36] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
Although feedback inhibition of noradrenaline release by coreleased nucleotides is a well known phenomenon, it remained unclear which P2 receptor subtypes and associated signalling cascades may be involved. In the rat pheochromocytoma cell line PC12, 2-methylthio-ADP reduced noradrenaline release triggered by K+ depolarization more potently than ADP and ATP, whereas UDP or UTP failed to do so. The inhibition by ADP was abolished by pertussis toxin and antagonized by reactive blue 2, 2-methylthio-AMP, and AR-C69931MX, but not by suramin. AR-C69931MX acted as a competitive antagonist with an apparent affinity of 2 nm, but did not alter noradrenaline release, when PC12 cells were continuously superfused. However, when the superfusion was halted during K+ depolarization, release was significantly reduced and this inhibition was attenuated by AR-C69931MX, thus revealing ongoing autoinhibition. Rises in cellular cyclic AMP did not alter depolarization-evoked release nor its reduction by ADP, even though the nucleotide did inhibit cyclic AMP accumulation. ADP and the direct Ca2+ channel blocker Cd2+ inhibited voltage-activated Ca2+ currents, but not ATP-induced currents, and both agents reduced K+-evoked, but not ATP-evoked, release. Hence, if voltage-gated Ca2+ channels do not contribute to stimulation-evoked release, ADP fails to exert its inhibitory action. In primary cultures of rat sympathetic neurons, ADP also reduced Ca2+ currents and K+-evoked noradrenaline release, and AR-C69931MX acted again as competitive antagonist with an apparent affinity of 3 nm. These results show that P2Y12 receptors mediate an autoinhibition of transmitter release from PC12 cells and sympathetic neurons through an inhibition of voltage-gated Ca2+ channels.
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Affiliation(s)
- Stefan G Lechner
- Institute of Pharmacology, Medical University of Vienna, Waehringerstrasse 13a, A-1090 Vienna, Austria
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20
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Arun KHS, Kaul CL, Ramarao P. Green fluorescent proteins in receptor research: An emerging tool for drug discovery. J Pharmacol Toxicol Methods 2005; 51:1-23. [PMID: 15596111 DOI: 10.1016/j.vascn.2004.07.006] [Citation(s) in RCA: 16] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/05/2003] [Accepted: 07/27/2004] [Indexed: 01/20/2023]
Abstract
In the last five years, green fluorescent protein (GFP) has emerged from being a mere curiosity to become a reliable tool for molecular pharmacological research. GFP produces an intense and stable green fluorescence noncatalytically by absorbing blue light maximally at 395 nm and emitting green light with a peak at 509 nm. It consists of 238 amino acids and its molecular mass is 27-30 kDa. GFP fluorescence occurs without cofactors and this property allows GFP fluorescence to be utilised in nonnative organisms, wherein it can be used as a reporter. This use of GFP permits real-time analysis of receptor dynamics. The emitted fluorescence can be used as a nontoxic marker and detected using fluorescence-activated cell sorting (FACS), thus avoiding any staining procedure, expensive mRNA analysis or hazardous radiolabeled binding assays. The potential value of GFP has also been recognized in orphan receptor research, where various GFP-tagged therapeutic proteins have been constructed in an attempt to identify the endogenous ligand(s). These chimeric proteins have been used to determine the site and time course of receptor expression and to relate receptor dynamics with therapeutic outcome. The preparation of new GFP constructs for identifying germ layer cells (endodermal, ectodermal, and mesodermal), as well as neuronal, haematopoietic, endothelial, and cartilage cells, has provided a useful battery of tissue/receptor-specific screening assays for new chemical entities. Genetically engineered cells with GFP expression have provided a valuable tool for automated analysis, and can be adapted for high-throughput systems. GFP is being increasingly utilised for the study of receptor dynamics, where, having already proved beneficial, it will likely continue to contribute towards the search for new classes of drugs, as well as to "de-orphaning" orphan receptors.
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Affiliation(s)
- K H S Arun
- Cardiovascular and Receptorology Laboratory, Department of Pharmacology and Toxicology, National Institute of Pharmaceutical Education and Research, Phase-X, Sector 67, S.A.S. Nagar (Mohali)-160 062, Punjab, India
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21
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Wolff SC, Qi AD, Harden TK, Nicholas RA. Polarized expression of human P2Y receptors in epithelial cells from kidney, lung, and colon. Am J Physiol Cell Physiol 2004; 288:C624-32. [PMID: 15525684 DOI: 10.1152/ajpcell.00338.2004] [Citation(s) in RCA: 35] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
Eight human G protein-coupled P2Y receptors (P2Y(1), P2Y(2), P2Y(4), P2Y(6), P2Y(11), P2Y(12), P2Y(13), and P2Y(14)) that respond to extracellular nucleotides have been molecularly identified and characterized. P2Y receptors are widely expressed in epithelial cells and play an important role in regulating epithelial cell function. Functional studies assessing the capacity of various nucleotides to promote increases in short-circuit current (I(sc)) or Ca(2+) mobilization have suggested that some subtypes of P2Y receptors are polarized with respect to their functional activity, although these results often have been contradictory. To investigate the polarized expression of the family of P2Y receptors, we determined the localization of the entire P2Y family after expression in Madin-Darby canine kidney (MDCK) type II cells. Confocal microscopy of polarized monolayers revealed that P2Y(1), P2Y(11), P2Y(12), and P2Y(14) receptors reside at the basolateral membrane, P2Y(2), P2Y(4), and P2Y(6) receptors are expressed at the apical membrane, and the P2Y(13) receptor is unsorted. Biotinylation studies and I(sc) measurements in response to the appropriate agonists were consistent with the polarized expression observed in confocal microscopy. Expression of the G(q)-coupled P2Y receptors (P2Y(1), P2Y(2), P2Y(4), P2Y(6), and P2Y(11)) in lung and colonic epithelial cells (16HBE14o- and Caco-2 cells, respectively) revealed a targeting profile nearly identical to that observed in MDCK cells, suggesting that polarized targeting of these P2Y receptor subtypes is not a function of the type of epithelial cell in which they are expressed. These experiments highlight the highly polarized expression of P2Y receptors in epithelial cells.
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Affiliation(s)
- Samuel C Wolff
- Department of Pharmacology, The University of North Carolina-Chapel Hill, 1027 Mary Ellen Jones Bldg., CB# 7365, Chapel Hill, NC 27599, USA
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22
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Dixon CJ, Hall JF, Webb TE, Boarder MR. Regulation of rat hepatocyte function by P2Y receptors: focus on control of glycogen phosphorylase and cyclic AMP by 2-methylthioadenosine 5'-diphosphate. J Pharmacol Exp Ther 2004; 311:334-41. [PMID: 15152027 DOI: 10.1124/jpet.104.067744] [Citation(s) in RCA: 23] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022] Open
Abstract
Hepatocyte function is regulated by several P2Y receptor subtypes. Here we report that 2-methylthioadenosine 5'-diphosphate (2-MeSADP), an agonist at P2Y(1), P2Y(12), and P2Y(13) receptors, potently (threshold 30 nM) stimulates glycogen phosphorylase in freshly isolated rat hepatocytes. Antagonism by N(6)-methyl 2'-deoxyadenosine 3',5'-bisphosphate (MRS 2179) confirms that this response is mediated by P2Y(1) receptors. In addition, in these cells, both 2-MeSADP and UTP inhibited glucagon-stimulated cyclic AMP accumulation. This inhibitory effect of 2-MeSADP was not reversed by the P2Y(1) antagonists, adenosine-3'-phosphate-5'-phosphate (A3P5P) or MRS 2179, both in the range 1 to 300 microM, indicating that it was not mediated by P2Y(1) receptors. This contrasts with the increase in cytosolic free Ca(2+) concentration ([Ca(2+)](c)) induced by 2-MeSADP, which has shown to be inhibited by A3P5P. Pertussis toxin abolished the inhibitory effect of both UTP and 2-MeSADP. After culture of cells for 48 h, the ability of 2-MeSADP to inhibit cyclic AMP accumulation was greatly diminished. Reverse transcriptase-polymerase chain reaction analysis revealed that during this culture period, there was a decline in the ability to detect transcripts for P2Y(12) and P2Y(13) receptors, both of which are activated by 2-MeSADP and negatively coupled to adenylyl cyclase. However, in freshly isolated cells, the P2Y(12) and P2Y(13) receptor antagonist, 2-propylthio-beta,gamma-dichloromethylene-d-ATP (AR-C67085) (10 nM to 300 microM) did not alter the ability of 2-MeSADP to inhibit glucagon-stimulated cyclic AMP accumulation. We conclude that 2-MeSADP regulates rat hepatocyte glycogen phosphorylase by acting on P2Y(1) receptors coupled to raised [Ca(2+)](c), and by inhibiting cyclic AMP levels by an unknown G(i)-coupled receptor subtype, distinct from P2Y(1), P2Y(12), or P2Y(13) receptors.
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Affiliation(s)
- C Jane Dixon
- The Cell Signaling Laboratory, Leicester School of Pharmacy, The Hawthorn Building, De Montfort University, Leicester LE1 9BH, United Kingdom
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23
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Zhong X, Kriz R, Seehra J, Kumar R. N-linked glycosylation of platelet P2Y12 ADP receptor is essential for signal transduction but not for ligand binding or cell surface expression. FEBS Lett 2004; 562:111-7. [PMID: 15044010 DOI: 10.1016/s0014-5793(04)00191-7] [Citation(s) in RCA: 33] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/13/2003] [Revised: 01/12/2004] [Accepted: 01/29/2004] [Indexed: 10/26/2022]
Abstract
P(2)Y(12) receptor is a G(i)-coupled adenosine diphosphate (ADP) receptor with a critical role in platelet aggregation. It contains two potential N-linked glycosylation sites at its extra cellular amino-terminus, which may modulate its activity. Studies of both tunicamycin treatment and site-directed mutagenesis have revealed a dispensable role of the N-linked glycosylation in the receptor's surface expression and ligand binding activity. However, the non-glycosylated P(2)Y(12) receptor is defective in the P(2)Y(12)-mediated inhibition of the adenylyl cyclase activity. Thus the study uncovers an unexpected vital role of N-linked glycans in receptor's signal transducing step but not in surface expression or ligand binding.
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Affiliation(s)
- Xiaotian Zhong
- Department of Chemical and Screening Sciences, Wyeth Research, 85 Bolton Street, Cambridge, MA 02140, USA
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24
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Marcet B, Chappe V, Delmas P, Gola M, Verrier B. Negative regulation of CFTR activity by extracellular ATP involves P2Y2 receptors in CFTR-expressing CHO cells. J Membr Biol 2004; 194:21-32. [PMID: 14502440 DOI: 10.1007/s00232-003-2021-0] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/13/2002] [Indexed: 11/30/2022]
Abstract
Extracellular nucleotides exert autocrine/ paracrine effects on ion transport by activating P2 receptors. We studied the effects of extracellular ATP and UTP on the cystic fibrosis transmembrane conductance regulator (CFTR) channel stably expressed in Chinese Hamster Ovary cells (CHO-BQI cells). CFTR activity was measured using the (125I) iodide efflux technique and whole-cell patch-clamp recording in response to either forskolin or xanthine derivatives. Using RT-PCR and intracellular calcium concentration ([Ca2+]i) measurement, we showed that CHO-BQI cells express P2Y2 but not P2Y4 receptors. While ATP and UTP induced similar increases in [Ca2+]i, pre-addition by one of these two agonists desensitized the response for the other, suggesting that ATP- and UTP-induced [Ca2+]i increases were mediated by a common receptor, which was identified as the P2Y2 subtype. CFTR activity was reduced by ATP and UTP but not by ADP or adenosine applications. This inhibitory effect of ATP on CFTR activity was not due to a change in cAMP level. Furthermore, CFTR activation by forskolin or IBMX failed to promote [Ca2+]i increase, suggesting that CFTR activation did not generate an ATP release large enough to stimulate P2Y2 receptors. Taken together, our results show that endogenous P2Y2 receptor activation downregulates CFTR activity in a cAMP-independent manner in CHO cells.
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Affiliation(s)
- B Marcet
- Institut de Neurosciences Physiologiques et Cognitives, CNRS - INPC, 13402 Marseille, France.
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25
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Burnstock G, Knight GE. Cellular Distribution and Functions of P2 Receptor Subtypes in Different Systems. INTERNATIONAL REVIEW OF CYTOLOGY 2004; 240:31-304. [PMID: 15548415 DOI: 10.1016/s0074-7696(04)40002-3] [Citation(s) in RCA: 581] [Impact Index Per Article: 29.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/22/2022]
Abstract
This review is aimed at providing readers with a comprehensive reference article about the distribution and function of P2 receptors in all the organs, tissues, and cells in the body. Each section provides an account of the early history of purinergic signaling in the organ?cell up to 1994, then summarizes subsequent evidence for the presence of P2X and P2Y receptor subtype mRNA and proteins as well as functional data, all fully referenced. A section is included describing the plasticity of expression of P2 receptors during development and aging as well as in various pathophysiological conditions. Finally, there is some discussion of possible future developments in the purinergic signaling field.
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Affiliation(s)
- Geoffrey Burnstock
- Autonomic Neuroscience Institute, Royal Free and University College Medical School, London NW3 2PF, United Kingdom
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26
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Herold CL, Qi AD, Harden TK, Nicholas RA. Agonist versus antagonist action of ATP at the P2Y4 receptor is determined by the second extracellular loop. J Biol Chem 2003; 279:11456-64. [PMID: 14670966 PMCID: PMC1821344 DOI: 10.1074/jbc.m301734200] [Citation(s) in RCA: 37] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
UTP is a potent full agonist at both the human P2Y(4) (hP2Y(4)) and rat P2Y(4) (rP2Y(4)) receptor. In contrast, ATP is a potent full agonist at the rP2Y(4) receptor but is a similarly potent competitive antagonist at the hP2Y(4) receptor. To delineate the structural determinants of agonism versus antagonism in these species homologues, we expressed a series of human/rat P2Y(4) receptor chimeras in 1321N1 human astrocytoma cells and assessed the capacity of ATP and UTP to mobilize intracellular Ca(2+). Replacement of the NH(2) terminus of the hP2Y(4) receptor with the corresponding region of the rP2Y(4) receptor resulted in a receptor that was activated weakly by ATP, whereas replacement of the second extracellular loop (EL2) of the hP2Y(4) receptor with that of the rP2Y(4) receptor yielded a chimeric receptor that was activated fully by UTP and near fully by ATP, albeit with lower potencies than those observed at the rP2Y(4) receptor. These potencies were increased, and ATP was converted to a full agonist by replacing both the NH(2) terminus and EL2 in the hP2Y(4) receptor with the corresponding regions from the rP2Y(4) receptor. Mutational analysis of the five divergent amino acids in EL2 between the two receptors revealed that three amino acids, Asn-177, Ile-183, and Leu-190, contribute to the capacity of EL2 to impart ATP agonism. Taken together, these results suggest that the second extracellular loop and the NH(2) terminus form a functional motif that plays a key role in determining whether ATP functions as an agonist or antagonist at mammalian P2Y(4) receptors.
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Affiliation(s)
- Christopher L Herold
- Department of Pharmacology, University of North Carolina, Chapel Hill, North Carolina 27599-7365, USA
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27
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Brindikova TA, Bourcier N, Torres B, Pchejetski D, Gekle M, Maximov GV, Montminy V, Insel PA, Orlov SN, Isenring P. Purinergic-induced signaling in C11-MDCK cells inhibits the secretory Na-K-Cl cotransporter. Am J Physiol Cell Physiol 2003; 285:C1445-53. [PMID: 12917108 DOI: 10.1152/ajpcell.00386.2002] [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] [Indexed: 11/22/2022]
Abstract
Purinergic inhibition of Na-K-Cl cotransport has been noted in various renal epithelial cells derived from the collecting tubule, including Madin-Darby canine kidney (MDCK) cells. In recent studies, we have observed purinergic inhibition of Na-K-Cl cotransport in C11-MDCK subclones (alpha-intercalated-like cells). Interestingly, Na-K-Cl cotransport activity was also detected in C7-MDCK subclones (principal-like cells) but was not affected by ATP. In this investigation, we have transfected the human Na-K-Cl cotransporter (huNKCC1) in both C11 and C7 cells to determine whether these differences in NKCC regulation by ATP were due to cell-specific purinoceptor signaling pathways or to cell-specific isoforms/splice variants of the transporter. In both cell lines, we found that endogenous as well as huNKCC1-derived cotransport activity was restricted to the basolateral side. In addition, we were able to show that extracellular application of 100 microM ATP or 100 microM UTP abolished NKCC activity in both mock- and huNKCC1-transfected C11 cells but not in mock- and huNKCC1-transfected C7 cells; in C11 cells, intriguingly, this inhibition was not affected by inhibitors of RNA and protein synthesis and occurred even though expression levels of UTP-sensitive P2Y2-, P2Y4-, and P2Y6-purinoceptors were not different from those observed in C7 cells. These results suggest that C11 cells express an undetermined type of UTP-sensitive P2-purinoceptors or a unique P2Y-purinoceptor-triggered signaling cascade that leads to inhibition of NKCC1.
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Affiliation(s)
- Tatyana A Brindikova
- L'Hôtel-Dieu de Québec Research Center, 10 rue McMahon (Rm. 3852 QC, Canada G1R 2J6
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28
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29
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Abstract
Compartmentation plays a critical role in determining the specificity and efficacy of signaling by adenosine 3',5'-monophosphate (cAMP) and other second messengers. It has become apparent that all of the protein components of the cAMP signaling pathway are subject to regulation and may be localized to particular subcellular compartments. This Perspective discusses recent research concerning the importance of cAMP phosphodiesterase localization in cAMP signaling, functional implications of the organization of this pathway's protein components into macromolecular complexes, and common themes in the compartmentation of cAMP- and Ca2+-mediated signaling pathways.
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Affiliation(s)
- Laurence L Brunton
- Department of Pharmacology 0636, University of California San Diego Medical School, 9500 Gilman Drive, La Jolla, CA 92093-0636, USA.
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30
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White PJ, Webb TE, Boarder MR. Characterization of a Ca2+ response to both UTP and ATP at human P2Y11 receptors: evidence for agonist-specific signaling. Mol Pharmacol 2003; 63:1356-63. [PMID: 12761346 DOI: 10.1124/mol.63.6.1356] [Citation(s) in RCA: 70] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022] Open
Abstract
Previous reports on heterologously-expressed human P2Y11 receptors have indicated that ATP, but not UTP, is an agonist stimulating both phosphoinositidase C and adenylyl cyclase. Consistent with these findings, we report that in 1321N1 cells expressing human P2Y11 receptors, UTP stimulation did not lead to accumulation of inositol(poly)phosphates under conditions in which ATP gave a robust, concentration-dependent effect. Unexpectedly, however, both UTP and ATP stimulated increases in cytosolic Ca2+ concentration ([Ca2+]c), with both nucleotides achieving similar EC50 and maximal responses. The responses to maximally effective concentrations of ATP and UTP were not additive. The [Ca2+]c increase in response to UTP was less dependent on extracellular Ca2+ than was the response to ATP. AR-C67085 (2-propylthio-beta,gamma-difluoromethylene-d-ATP, a P2Y11-selective agonist), adenosine 5'-O-(3-thiotriphosphate), and benzoyl ATP were all full agonists with potencies similar to those of ATP and UTP. In desensitization experiments, exposure to ATP resulted in loss of the UTP response; this response was more sensitive to desensitization than that of ATP. Pertussis toxin pretreatment attenuated the response to UTP but left the ATP response unaffected. The presence of 2-aminoethyl diphenylborate differentially affected the responses of ATP and UTP. No mRNA transcripts for P2Y2 or P2Y4 were detectable in the P2Y11-expressing cells. We conclude that UTP is a Ca2+-mobilizing agonist at P2Y11 receptors and that ATP and UTP acting at the same receptor recruit distinct signaling pathways. This example of agonist-specific signaling is discussed in terms of agonist trafficking and differential signal strength.
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Affiliation(s)
- Pamela J White
- Cell Signaling Laboratory, School of Pharmacy, De Montfort University, The Hawthorn Building, Leicester LE1 9BH, England.
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Hughes RJ, Torres B, Zambon A, Arthur D, Bohmann C, Rump LC, Insel PA. Expression of multiple P2Y receptors by MDCK-D1 cells: P2Y1 receptor cloning and signaling. Drug Dev Res 2003. [DOI: 10.1002/ddr.10196] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/05/2022]
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Dubyak GR. Knock-out mice reveal tissue-specific roles of P2Y receptor subtypes in different epithelia. Mol Pharmacol 2003; 63:773-6. [PMID: 12644576 DOI: 10.1124/mol.63.4.773] [Citation(s) in RCA: 52] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/11/2022] Open
Affiliation(s)
- George R Dubyak
- Department of Physiology and Biophysics, Case Western Reserve University, School of Medicine, Cleveland, Ohio 44106, USA.
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Molecular and Biological Properties of P2Y Receptors. CURRENT TOPICS IN MEMBRANES 2003. [DOI: 10.1016/s1063-5823(03)01003-2] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register]
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Dixon CJ, Hall JF, Boarder MR. ADP stimulation of inositol phosphates in hepatocytes: role of conversion to ATP and stimulation of P2Y2 receptors. Br J Pharmacol 2003; 138:272-8. [PMID: 12522099 PMCID: PMC1573642 DOI: 10.1038/sj.bjp.0705016] [Citation(s) in RCA: 17] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/08/2022] Open
Abstract
1 Accumulation of inositol (poly)phosphates (InsP(x)) has been studied in rat hepatocytes labelled with [(3)H]inositol. Stimulation with ADP resulted in a significant increase in total [(3)H]InsP(x), whereas 2-MeSADP had only a small effect and ADPbetaS was ineffective. UTP and ITP also stimulated substantial increases in [(3)H]InsP(x). 2 The dose-response curve to ADP was largely unaltered by the presence of the P2Y(1) antagonist, adenosine-3'-phosphate-5'-phosphate (A3P5P). Similarly, inclusion of MRS 2179, a more selective P2Y(1) antagonist, had no effect on the dose-response curve to ADP. 3 The inclusion of hexokinase in the assay reduced, but did not abolish, the response to ADP. 4 HPLC analysis revealed that ADP in the medium was rapidly converted to AMP and ATP. The inclusion of hexokinase removed ATP, but exacerbated the decline in ADP concentration, leading to increased levels of AMP. 2-MeSADP was stable in the medium and ATP was largely unaffected. 5 The addition of the adenylate kinase inhibitor, diadenosine pentaphosphate (Ap(5)A) significantly reduced the ADP response. HPLC analysis conducted in parallel demonstrated that this treatment inhibited conversion of ADP to ATP and AMP. 6 Inclusion of the P1 antagonist CGS 15943 had no effect on the dose-response curve to ADP. 7 These observations indicate that hepatocytes respond to ADP with an increase in inositol (poly)phosphates following conversion to ATP. P2Y(1) activation in hepatocytes does not appear to be coupled to inositol 1,4,5-trisphosphate (Ins(1,4,5)P(3)) production.
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Affiliation(s)
- C Jane Dixon
- School of Molecular Sciences, The Hawthorn Building, De Montfort University, The Gateway, Leicester LE1 9BH, UK.
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Fong AY, Krstew EV, Barden J, Lawrence AJ. Immunoreactive localisation of P2Y1 receptors within the rat and human nodose ganglia and rat brainstem: comparison with [alpha 33P]deoxyadenosine 5'-triphosphate autoradiography. Neuroscience 2002; 113:809-23. [PMID: 12182888 DOI: 10.1016/s0306-4522(02)00237-3] [Citation(s) in RCA: 37] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/15/2022]
Abstract
The present study employed standard peroxidase immunohistochemistry to map the distribution of P2Y(1) receptors in the rat brainstem and nodose ganglia and characterised the binding profile of [alpha(33)P]dATP. Binding of [alpha(33)P]dATP was fully displaceable by adenosine 5'-triphosphate (ATP), and was found on both human and rat nodose ganglia, and throughout the rat brainstem, including the nucleus tractus solitarius and ventrolateral medulla. [Alpha(33)P]dATP binding in the human nodose ganglia was significantly displaced by both 2-methylthio ATP and alpha,beta-methylene ATP, but not by uridine 5'-triphosphate, pyridoxalphosphate-6-azophenyl-2',4'-disulfonic acid, 8,8'-(carbonylbis(imino-4,1-phenylenecarbonylimino-4,1-phenylenecarbonylimino))bis(1,3,5-naphtalenetrisulfonic) acid (NF279) or N-ethylcarboxamidoadenosine. [Alpha(33)P]dATP binding in the rat nodose ganglia and brainstem was significantly displaced by only 2-methylthio ATP, suggesting that [alpha(33)P]dATP is binding to P2Y receptors in the rat. Binding of [alpha(33)P]dATP was also significantly displaced by alpha,beta-methylene adenosine 5'-diphosphate, suggesting a component of the binding is to endogenous ecto-5'-nucleotidase, however, almost all binding could be displaced by a combination of receptor agonists (2-methylthio ATP, uridine 5'-triphosphate and alpha,beta-methylene ATP), suggesting preferential binding to receptors. Immunoreactivity to P2Y(1) receptor (P2Y(1)-IR) exhibited similar distribution patterns to [alpha(33)P]dATP binding, with a clear topographic profile. Particularly dense P2Y(1)-IR labeling was evident in cells and fibres of the dorsal vagal complex. Immunolabeling was also present in the dorsal motor nucleus of the vagus and nucleus ambiguus, indicating the possibility of P2Y(1) receptors on vagal efferents. Unilateral vagal ligation was also performed to examine the transport of P2Y(1) receptor, using both immunohistochemistry and [alpha(33)P]dATP autoradiography. Accumulations of both P2Y(1)-IR and [alpha(33)P]dATP binding were apparent adjacent to both ligatures, suggesting bi-directional transport of P2Y(1) receptors along the rat vagus nerve. This current study represents the first description of P2Y(1) receptor distribution within the rodent brainstem and nodose ganglion and also characterises [alpha(33)P]dATP binding to P2Y receptors.
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Affiliation(s)
- A Y Fong
- Department of Pharmacology, P.O. Box 13E, Monash University, Wellington Road, Clayton, Vic 3800, Australia
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Jacobson KA, Jarvis MF, Williams M. Purine and pyrimidine (P2) receptors as drug targets. J Med Chem 2002; 45:4057-93. [PMID: 12213051 DOI: 10.1021/jm020046y] [Citation(s) in RCA: 229] [Impact Index Per Article: 10.4] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Affiliation(s)
- Kenneth A Jacobson
- Molecular Recognition Section, Laboratory of Bioorganic Chemistry, National Institute of Diabetes, Digestive and Kidney Diseases/NIH, Bethesda, MD 20892, USA
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Torres B, Zambon AC, Insel PA. P2Y11 receptors activate adenylyl cyclase and contribute to nucleotide-promoted cAMP formation in MDCK-D(1) cells. A mechanism for nucleotide-mediated autocrine-paracrine regulation. J Biol Chem 2002; 277:7761-5. [PMID: 11788591 DOI: 10.1074/jbc.m110352200] [Citation(s) in RCA: 50] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
Extracellular nucleotides activate P2Y receptors, thereby increasing cAMP formation in Madin-Darby canine kidney (MDCK-D(1)) cells, which express P2Y(1), P2Y(2), and P2Y(11) receptors (Post, S. R., Rump, L. C., Zambon, A., Hughes, R. J., Buda, M. D., Jacobson, J. P., Kao, C. C., and Insel, P. A. (1998) J. Biol. Chem. 273, 23093-23097). The cyclooxygenase inhibitor indomethacin (indo) eliminates UTP-promoted cAMP formation (i.e. via P2Y(2) receptors) but only partially blocks ATP-promoted cAMP formation. The latter response is completely blocked by the nonselective P2Y receptor antagonist suramin. We have sought to identify the mechanism for this P2Y receptor-mediated, indo-resistant cAMP formation. The agonist rank order potencies for cAMP formation were: ADP beta S > or = MT-ADP > 2-MT-ATP > ADP, ATP, ATP gamma S > UTP, AMP, adenosine. We found a similar rank order in MDCK-D(1) cells overexpressing cloned green fluorescent protein-tagged P2Y(11) receptors, but the potency of the agonists was enhanced, consistent with a P2Y(11) receptor-mediated effect. cAMP generation by the P2Y(1) and P2Y(11) receptor agonist ADP beta S was not inhibited by several P2Y(1)-selective antagonists (PPADS, A2P5P, and MRS 2179). Forskolin synergistically enhanced cAMP generation in response to ADP beta S or PGE(2), implying that, like PGE(2), ADP beta S activates adenylyl cyclase via G(s), a conclusion supported by results showing ADP beta S and MT-ADP promoted activation of adenylyl cyclase activity in MDCK-D(1) membranes. We conclude that nucleotide-promoted, indo-resistant cAMP formation in MDCK-D(1) cells occurs via G(s)-linked P2Y(11) receptors. These data describing adenylyl cyclase activity via endogenous P2Y(11) receptors define a mechanism by which released nucleotides can increase cAMP in MDCK-D(1) and other P2Y(11)-containing cells.
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Affiliation(s)
- Brian Torres
- Department of Pharmacology, University of California, San Diego, La Jolla, California 92093-0636
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Sak K, Webb TE. A retrospective of recombinant P2Y receptor subtypes and their pharmacology. Arch Biochem Biophys 2002; 397:131-6. [PMID: 11747319 DOI: 10.1006/abbi.2001.2616] [Citation(s) in RCA: 57] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
Since the first cloning of P2Y receptor sequences in 1993 it has become apparent that this family of G-protein-coupled receptors is omnipresent. At least 25 individual sequences entered in the GenBank sequence database encode P2Y receptors from a variety of species ranging from the little skate Raja erinacea to man. In man, six receptor subtypes have been cloned and found to be functionally active (P2Y(1), P2Y(2), P2Y(4), P2Y(6), P2Y(11), and P2Y(12)). In this article a review of the P2Y receptor subtypes is presented considering both their sequences and the pharmacological profiles of the encoded receptors expressed in heterologous expression systems.
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Affiliation(s)
- Katrin Sak
- Hematology-Oncology Clinic, Tartu University, Ulikooli 18, Tartu 50090, Estonia
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Qi AD, Zambon AC, Insel PA, Nicholas RA. An arginine/glutamine difference at the juxtaposition of transmembrane domain 6 and the third extracellular loop contributes to the markedly different nucleotide selectivities of human and canine P2Y11 receptors. Mol Pharmacol 2001; 60:1375-82. [PMID: 11723245 DOI: 10.1124/mol.60.6.1375] [Citation(s) in RCA: 44] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022] Open
Abstract
The recently cloned canine P2Y11 receptor (cP2Y11) and its human homolog (hP2Y11) were stably expressed in Chinese hamster ovary cells (CHO-K1) and 1321N1 human astrocytoma cells, and their agonist selectivities and coupling efficiencies to phospholipase C and adenylyl cyclase were assessed. Adenosine triphosphate nucleotides were much more potent and efficacious at the hP2Y11 receptor than their corresponding diphosphates in promoting both inositol phosphate and cyclic AMP accumulation. In contrast, adenosine diphosphate nucleotides were considerably more potent at the cP2Y11 receptor than their corresponding triphosphate analogs. The tri- versus diphosphate specificity of the two receptors was further confirmed in studies using Ca(2+) mobilization as a measure of receptor activation under conditions that minimized nucleotide degradation. Moreover, 2-methylthioadenosine-5'-triphosphate and 2-methylthioadenosine-5'-diphosphate were 58- and 75-fold more potent than ATP and ADP, respectively, at the cP2Y11 receptor compared with only 2- to 3-fold more potent at the hP2Y11 receptor. Mutational analysis revealed that the change of Arg-265, which is located at the juxtaposition of transmembrane domain 6 and the third extracellular loop in the hP2Y11 receptor, to glutamine in the cP2Y11 receptor is at least partly responsible for the diphosphate selectivity but not the increased sensitivity to 2-thioether-substituted adenine nucleotides at the canine receptor. These results imply a key role for a positively charged arginine residue in contributing to the recognition of extracellular nucleotides by the P2Y11 receptor and perhaps other P2Y receptors.
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Affiliation(s)
- A D Qi
- Department of Pharmacology, University of North Carolina, Chapel Hill, North Carolina 27599-7365, USA
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Hermosilla R, Schülein R. Sorting functions of the individual cytoplasmic domains of the G protein-coupled vasopressin V(2) receptor in Madin Darby canine kidney epithelial cells. Mol Pharmacol 2001; 60:1031-9. [PMID: 11641431 DOI: 10.1124/mol.60.5.1031] [Citation(s) in RCA: 23] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022] Open
Abstract
Previous studies have shown that the G protein-coupled human vasopressin V(2) receptor (V(2) receptor) is expressed predominantly in the basolateral membrane of Madin Darby canine kidney type II (MDCKII) epithelial cells at steady state. Here we have assessed the influence of the individual cytoplasmic domains of the V(2) receptor on polarized sorting in MDCKII cells. The second (ICL2) and third (ICL3) intracellular loops and the C-terminal tail were fused separately to a green fluorescent protein-tagged receptor fragment comprising the first transmembrane domain and flanking regions. We show that the ICL2 domain of the V(2) receptor alone promotes basolateral cell surface expression and thus seems to contain the basolateral sorting signal of the V(2) receptor. Fusion of the other cytoplasmic domains, however, does not lead to a randomized cell surface expression. The C-terminal tail of the V(2) receptor promotes apical targeting. Fusion of ICL3 leads to a receptor fragment that is retained in the endoplasmic reticulum (ER). The results are consistent with a model in which the V(2) receptor contains signals for both apical and basolateral cell surface expression, the latter being dominant. Furthermore, ICL3 may contain a RXR [corrected] ER retention signal, which is not accessible in the correctly folded full-length receptor but which is unmasked when ICL3 is fused alone.
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Affiliation(s)
- R Hermosilla
- Forschungsinstitut für Molekulare Pharmakologie, Berlin, Germany
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