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Adenosine Receptors as a Biological Pathway for the Anti-Inflammatory and Beneficial Effects of Low Frequency Low Energy Pulsed Electromagnetic Fields. Mediators Inflamm 2017; 2017:2740963. [PMID: 28255202 PMCID: PMC5309410 DOI: 10.1155/2017/2740963] [Citation(s) in RCA: 50] [Impact Index Per Article: 7.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/20/2016] [Accepted: 01/12/2017] [Indexed: 12/22/2022] Open
Abstract
Several studies explored the biological effects of low frequency low energy pulsed electromagnetic fields (PEMFs) on human body reporting different functional changes. Much research activity has focused on the mechanisms of interaction between PEMFs and membrane receptors such as the involvement of adenosine receptors (ARs). In particular, PEMF exposure mediates a significant upregulation of A2A and A3ARs expressed in various cells or tissues involving a reduction in most of the proinflammatory cytokines. Of particular interest is the observation that PEMFs, acting as modulators of adenosine, are able to increase the functionality of the endogenous agonist. By reviewing the scientific literature on joint cells, a double role for PEMFs could be hypothesized in vitro by stimulating cell proliferation, colonization of the scaffold, and production of tissue matrix. Another effect could be obtained in vivo after surgical implantation of the construct by favoring the anabolic activities of the implanted cells and surrounding tissues and protecting the construct from the catabolic effects of the inflammatory status. Moreover, a protective involvement of PEMFs on hypoxia damage in neuron-like cells and an anti-inflammatory effect in microglial cells have suggested the hypothesis of a positive impact of this noninvasive biophysical stimulus.
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Burnstock G, Boeynaems JM. Purinergic signalling and immune cells. Purinergic Signal 2014; 10:529-64. [PMID: 25352330 PMCID: PMC4272370 DOI: 10.1007/s11302-014-9427-2] [Citation(s) in RCA: 222] [Impact Index Per Article: 22.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/04/2013] [Accepted: 09/12/2013] [Indexed: 11/28/2022] Open
Abstract
This review article provides a historical perspective on the role of purinergic signalling in the regulation of various subsets of immune cells from early discoveries to current understanding. It is now recognised that adenosine 5'-triphosphate (ATP) and other nucleotides are released from cells following stress or injury. They can act on virtually all subsets of immune cells through a spectrum of P2X ligand-gated ion channels and G protein-coupled P2Y receptors. Furthermore, ATP is rapidly degraded into adenosine by ectonucleotidases such as CD39 and CD73, and adenosine exerts additional regulatory effects through its own receptors. The resulting effect ranges from stimulation to tolerance depending on the amount and time courses of nucleotides released, and the balance between ATP and adenosine. This review identifies the various receptors involved in the different subsets of immune cells and their effects on the function of these cells.
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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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de Lera Ruiz M, Lim YH, Zheng J. Adenosine A2A Receptor as a Drug Discovery Target. J Med Chem 2013; 57:3623-50. [DOI: 10.1021/jm4011669] [Citation(s) in RCA: 204] [Impact Index Per Article: 18.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/17/2023]
Affiliation(s)
- Manuel de Lera Ruiz
- Department
of Chemical Research, Merck Research Laboratories, 770 Sumneytown Pike, West Point, Pennsylvania 19486, United States
| | - Yeon-Hee Lim
- Department
of Chemical Research, Merck Research Laboratories, 126 E. Lincoln Avenue, Rahway, New Jersey 07065, United States
| | - Junying Zheng
- Department
of Chemical Research, Merck Research Laboratories, 126 E. Lincoln Avenue, Rahway, New Jersey 07065, United States
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Banda V, Chandrasekaran B, Köse M, Vielmuth C, Müller CE, Chavva K, Gautham SK, Pillalamarri S, Mylavaram R, Akkinepally R, Pamulaparthy S, Banda N. Synthesis of Novel Pyrido[3,2-e][1,2,4]triazolo[1,5-c]pyrimidine Derivatives: Potent and Selective Adenosine A3Receptor Antagonists. Arch Pharm (Weinheim) 2013; 346:699-707. [DOI: 10.1002/ardp.201300003] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/11/2013] [Revised: 07/18/2013] [Accepted: 07/19/2013] [Indexed: 11/08/2022]
Affiliation(s)
- Veeraswamy Banda
- Fluoroorganic Division; Indian Institute of Chemical Technology; Tarnaka, Hyderabad Andhra Pradesh India
| | - Balakumar Chandrasekaran
- University Institute of Pharmaceutical Sciences and UGC Centre of Advanced Study in Pharmaceutical Sciences (UGC-CAS); Panjab University; Chandigarh Punjab India
| | - Meryem Köse
- PharmaCenter Bonn; University of Bonn; Pharmaceutical Institute, Pharmaceutical Chemistry I; Bonn Germany
| | - Christin Vielmuth
- PharmaCenter Bonn; University of Bonn; Pharmaceutical Institute, Pharmaceutical Chemistry I; Bonn Germany
| | - Christa E. Müller
- PharmaCenter Bonn; University of Bonn; Pharmaceutical Institute, Pharmaceutical Chemistry I; Bonn Germany
| | - Kurumurthy Chavva
- Fluoroorganic Division; Indian Institute of Chemical Technology; Tarnaka, Hyderabad Andhra Pradesh India
| | - Santhosh Kumar Gautham
- Fluoroorganic Division; Indian Institute of Chemical Technology; Tarnaka, Hyderabad Andhra Pradesh India
| | - Sambasivarao Pillalamarri
- Fluoroorganic Division; Indian Institute of Chemical Technology; Tarnaka, Hyderabad Andhra Pradesh India
| | | | | | - Shanthanrao Pamulaparthy
- Fluoroorganic Division; Indian Institute of Chemical Technology; Tarnaka, Hyderabad Andhra Pradesh India
| | - Narsaiah Banda
- Fluoroorganic Division; Indian Institute of Chemical Technology; Tarnaka, Hyderabad Andhra Pradesh India
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Boldyrev AA, Bryushkova EA, Vladychenskaya EA. NMDA receptors in immune competent cells. BIOCHEMISTRY (MOSCOW) 2012; 77:128-34. [DOI: 10.1134/s0006297912020022] [Citation(s) in RCA: 36] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/01/2023]
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Liu Y, Burger SK, Ayers PW, Vöhringer-Martinez E. Computational Study of the Binding Modes of Caffeine to the Adenosine A2A Receptor. J Phys Chem B 2011; 115:13880-90. [PMID: 21970461 DOI: 10.1021/jp2022049] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/21/2023]
Affiliation(s)
- Yuli Liu
- Department of Chemistry and Chemical Biology, McMaster University, 1280 Main Street West, Hamilton, ON L8S4M1, Canada
| | - Steven K. Burger
- Department of Chemistry and Chemical Biology, McMaster University, 1280 Main Street West, Hamilton, ON L8S4M1, Canada
| | - Paul W. Ayers
- Department of Chemistry and Chemical Biology, McMaster University, 1280 Main Street West, Hamilton, ON L8S4M1, Canada
| | - Esteban Vöhringer-Martinez
- Laboratorio de Química Teórica Computacional (QTC), Pontificia Universidad Católica de Chile, Casilla 306, Correo 22, Santiago, Chile
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Bellé LP, Bitencourt PER, Abdalla FH, Guerra RB, Funchal C, Moretto MB. An in vitro comparison of a new vinyl chalcogenide and sodium selenate on adenosine deaminase activity of human leukocytes. Chem Biol Interact 2010; 189:141-5. [PMID: 21172326 DOI: 10.1016/j.cbi.2010.12.010] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/28/2010] [Revised: 11/10/2010] [Accepted: 12/13/2010] [Indexed: 12/22/2022]
Abstract
Selenium (Se) is a dietary essential trace element with important biological roles. Sodium selenate (Na(2)SeO(4)) is an inorganic Se compound used in human and animal nutrition that acts as precursor for selenoprotein synthesis. The organoselenium 3-methyl-1-phenyl-2-(phenylseleno)oct-2-en-1-one (C(21)H(2)HOSe) is an α,β-unsaturated ketone functionalized vinyl chalcogenide that has been found as a potential tool in organic synthesis. Adenosine deaminase (ADA) is an important enzyme in the degradation of adenine nucleotides. In this study, we investigated the in vitro effects of both Se compounds on ADA activity and cell viability in leukocyte suspension (LS) of healthy donors (n=12). We first observed an inhibition of ADA activity using 0.1 μM of 3-methyl-1-phenyl-2-(phenylseleno)oct-2-en-1-one, and an increase in cellular viability when 30 μM were used. However, we did not observe alterations in the presence of sodium selenate. Moreover, both Se compounds did not alter lactate dehydrogenase activity and thiobarbituric acid reactive substance levels. These results suggest that the inhibition of ADA activity caused by α,β-unsaturated ketone may affect the adenosine levels in LS and modulate cell viability, attenuating conditions that involve the activation of the immune system.
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Burnstock G, Fredholm BB, North RA, Verkhratsky A. The birth and postnatal development of purinergic signalling. Acta Physiol (Oxf) 2010; 199:93-147. [PMID: 20345419 DOI: 10.1111/j.1748-1716.2010.02114.x] [Citation(s) in RCA: 98] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/16/2022]
Abstract
The purinergic signalling system is one of the most ancient and arguably the most widespread intercellular signalling system in living tissues. In this review we present a detailed account of the early developments and current status of purinergic signalling. We summarize the current knowledge on purinoceptors, their distribution and role in signal transduction in various tissues in physiological and pathophysiological conditions.
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Affiliation(s)
- G Burnstock
- Autonomic Neuroscience Centre, Royal Free and University College Medical School, London, UK.
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Minelli A, Bellezza I, Tucci A, Rambotti MG, Conte C, Culig Z. Differential involvement of reactive oxygen species and nucleoside transporters in cytotoxicity induced by two adenosine analogues in human prostate cancer cells. Prostate 2009; 69:538-47. [PMID: 19107848 DOI: 10.1002/pros.20900] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
Abstract
BACKGROUND Elevated levels of cellular oxidative stress represent a specific vulnerability of malignant cells and exposure to cytotoxic drugs is known to induce oxidative stress in cancer cells. The effects of two adenosine analogues, 2-chloroadenosine and 2-chlorodeoxyadenosine, were investigated to assess their mechanism of action in prostate cancer cells. METHODS Androgen-independent and -sensitive (PC3 and LNCaP) prostate cancer cells and mouse primary prostate cultures were used in the study. Proliferation and cell cycle progression were analyzed in the presence of 2-chloroadenosine and 2-chlorodeoxyadenosine. Adenosine receptors and nucleoside transporters expression were determined by RT-PCR. GSH and reactive oxygen species levels were determined by DTNB and DCFH-DA, respectively. Nuclear translocation of Nrf2 was assessed by Western blotting. RESULTS 2-Chloroadenosine marginally affected primary prostate cells viability whereas it was more potent than 2-chlorodeoxyadenosine in reducing viability and increasing apoptosis in both prostate cancer cell lines. Moreover, ROS levels and GSH content were markedly affected in PC3 whereas only ROS production was increased in LNCaP cells. The antioxidant butylated hydroxytoluene protected PC3 cells from GSH depletion and reduction in cell viability induced by 2-chloroadenosine. CONCLUSIONS 2-Chloroadenosine, but not 2-chlorodeoxyadenosine is capable of inducing apoptosis in prostate cancer cells, an effect which may be explained at least partially by the capacity of the nucleoside analogue to modify ROS and GSH levels. These observations may offer a rationale for the use of 2-chloroadenosine to improve the clinical efficacy of GSH-dependent antitumor drugs.
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Affiliation(s)
- Alba Minelli
- Dipartimento di Medicina Sperimentale Scienze Biochimiche, Sezione Biochimica Cellulare, Perugia, Italy.
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Varani K, De Mattei M, Vincenzi F, Gessi S, Merighi S, Pellati A, Ongaro A, Caruso A, Cadossi R, Borea PA. Characterization of adenosine receptors in bovine chondrocytes and fibroblast-like synoviocytes exposed to low frequency low energy pulsed electromagnetic fields. Osteoarthritis Cartilage 2008; 16:292-304. [PMID: 17698373 DOI: 10.1016/j.joca.2007.07.004] [Citation(s) in RCA: 87] [Impact Index Per Article: 5.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 02/01/2007] [Accepted: 07/03/2007] [Indexed: 02/02/2023]
Abstract
OBJECTIVE The present study describes the presence and binding parameters of the A1, A2A, A2B and A3 adenosine receptors in bovine chondrocytes and fibroblast-like synoviocytes. The effect of low frequency low energy pulsed electromagnetic fields (PEMFs) on the adenosine receptor affinity and density was studied. METHODS Saturation, competition binding experiments and Western blotting assays in the absence and in the presence of PEMFs on the adenosine receptors in bovine chondrocytes or fibroblast-like synoviocytes were performed. Thermodynamic analysis of the A2A or A3 binding was studied to investigate the forces driving drug-receptor coupling. In the adenylyl cyclase and proliferation assays the potency of typical high-affinity A2A or A3 agonists in the absence and in the presence of PEMFs was evaluated. RESULTS Bovine chondrocytes and fibroblast-like synoviocytes expressed all adenosine receptors. PEMFs evoked an up-regulation of A2A and A3 receptors and thermodynamic parameters indicate that adenosine binding is enthalpy and entropy driven. In PEMF-treated cells the potency of typical A2A or A3 agonists on cyclic AMP assays was significantly increased when compared with the untreated cells. PEMFs potentiated the effect of A2A or A3 agonists on cell proliferation in both cell types. CONCLUSIONS PEMFs mediate an up-regulation of A2A and A3 receptors related to an increase of their functional activities in bovine chondrocytes and fibroblast-like synoviocytes. No differences are present in adenosine affinity and in the drug-receptor interactions. Our data could be used as a trigger to future studies addressed to PEMFs and adenosine therapeutic intervention in inflammatory joint diseases.
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Affiliation(s)
- K Varani
- Department of Clinical and Experimental Medicine, University of Ferrara, Italy
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González MP, Terán C, Teijeira M. Search for new antagonist ligands for adenosine receptors from QSAR point of view. How close are we? Med Res Rev 2008; 28:329-71. [PMID: 17668454 DOI: 10.1002/med.20108] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/13/2023]
Abstract
In view of the large libraries of nucleoside analogues that are now being handled in organic synthesis, the identification of drug biological activity is advisable prior to synthesis and this can be achieved by employing predictive biological property methods. In this sense, Quantitative Structure-Activity Relationships (QSAR) or docking approaches have emerged as promising tools. Although a large number of in silico approaches have been described in the literature for the prediction of different biological activities, the use of QSAR applications to develop adenosine receptor (AR) antagonists is not common as for the case of the antibiotics and anticancer compounds for instance. The intention of this review is to summarize the present knowledge concerning computational predictions of new molecules as adenosine receptor antagonists.
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Ravyn V, Bostwick JR. Functional coupling of the Galpha(olf) variant XLGalpha(olf) with the human adenosine A2A receptor. J Recept Signal Transduct Res 2006; 26:241-58. [PMID: 16818375 DOI: 10.1080/10799890600710592] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/24/2022]
Abstract
A recently identified novel Galphaolf variant, XLGalphaolf, is shown to functionally couple to the human adenosine A2A receptor (A2AR). In Sf9 cells expressing A2AR, beta1, and gamma2, co-expression of XLGalphaolf increased NECA-induced [35S]GTPgammaS binding from approximately 130% to 300% of basal levels. Pharmacological characteristics of A2AR ligands on these cells were evaluated by using [3H]ZM241385- and [35S]GTPgammaS- binding assays. The rank order of the equilibrium binding constants (Kd or Ki) of adenosine receptor ligands were [3H]ZM241385 approximately CGS15943 < MRS1220 < < CV1808 approximately NECA < CGS21680 approximately adenosine < IBMECA < HEMADO approximately CPA approximately CCPA. The rank order of EC50 values for agonists were CV1808 approximately NECA < adenosine approximately CGS26180 < IBMECA < HEMADO approximately CPA approximately CCPA. This pharmacology is consistent with the literature for A2AR and suggests that Sf9 cells co-expressing A2AR, beta1, gamma2, and XLGalphaolf could serve as a heterologous expression system for A2AR drug screening.
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Affiliation(s)
- Vipa Ravyn
- Lead Discovery, AstraZeneca Pharmaceuticals, Wilmington, Delaware 19850, USA
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Bours MJL, Swennen ELR, Di Virgilio F, Cronstein BN, Dagnelie PC. Adenosine 5'-triphosphate and adenosine as endogenous signaling molecules in immunity and inflammation. Pharmacol Ther 2006; 112:358-404. [PMID: 16784779 DOI: 10.1016/j.pharmthera.2005.04.013] [Citation(s) in RCA: 766] [Impact Index Per Article: 42.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/19/2005] [Accepted: 04/20/2005] [Indexed: 02/07/2023]
Abstract
Human health is under constant threat of a wide variety of dangers, both self and nonself. The immune system is occupied with protecting the host against such dangers in order to preserve human health. For that purpose, the immune system is equipped with a diverse array of both cellular and non-cellular effectors that are in continuous communication with each other. The naturally occurring nucleotide adenosine 5'-triphosphate (ATP) and its metabolite adenosine (Ado) probably constitute an intrinsic part of this extensive immunological network through purinergic signaling by their cognate receptors, which are widely expressed throughout the body. This review provides a thorough overview of the effects of ATP and Ado on major immune cell types. The overwhelming evidence indicates that ATP and Ado are important endogenous signaling molecules in immunity and inflammation. Although the role of ATP and Ado during the course of inflammatory and immune responses in vivo appears to be extremely complex, we propose that their immunological role is both interdependent and multifaceted, meaning that the nature of their effects may shift from immunostimulatory to immunoregulatory or vice versa depending on extracellular concentrations as well as on expression patterns of purinergic receptors and ecto-enzymes. Purinergic signaling thus contributes to the fine-tuning of inflammatory and immune responses in such a way that the danger to the host is eliminated efficiently with minimal damage to healthy tissues.
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Affiliation(s)
- M J L Bours
- Maastricht University, Department of Epidemiology, Nutrition and Toxicology Research Institute Maastricht, P.O. Box 616, 6200 MD Maastricht, The Netherlands.
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Christensen NJ, Bratholm P. The cAMP response to isoprenaline in mononuclear cells is markedly increased in the presence of platelets. Life Sci 2006; 79:601-5. [PMID: 16513139 DOI: 10.1016/j.lfs.2006.02.001] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/14/2005] [Revised: 01/13/2006] [Accepted: 02/01/2006] [Indexed: 11/22/2022]
Abstract
We have previously shown that the addition of platelets to mononuclear cells (MNC) increases cAMP in MNC. This response may be of interest because the physical interaction between platelets and MNC plays an important role in the inflammatory process. We have now demonstrated that the addition of both isoprenaline and platelets to MNC resulted in a marked amplification of the cAMP response. Prostaglandins, ATP and adenosine and the P-selectin ligand PSGL-1 could not account for the response. No substance was found in the supernatant that could increase cAMP in MNC. W7, a Ca(2+)-calmodulin inhibitor and the addition of EDTA reduced the response to both platelets and isoprenaline. Furthermore, we have demonstrated that mRNA for type I adenylyl cyclase, which is sensitive to Ca(2+), is present in MNC. No increase in Ca(2+) in the cytoplasma in MNC was recorded, however, by quantitative fluorescence microscopy after addition of platelets to MNC. It is possible that there are small increments in Ca(2+) at the binding sites, which we were unable to detect by our technique. Alternatively the binding of platelets to MNC may induce intermolecular interactions in the cell membrane which may facilitate the synthesis of cAMP.
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Manera C, Betti L, Cavallini T, Giannaccini G, Martinelli A, Ortore G, Saccomanni G, Trincavelli L, Tuccinardi T, Ferrarini PL. 1,8-Naphthyridin-4-one derivatives as new ligands of A2A adenosine receptors. Bioorg Med Chem Lett 2005; 15:4604-10. [PMID: 16099648 DOI: 10.1016/j.bmcl.2005.06.064] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/30/2005] [Revised: 06/23/2005] [Accepted: 06/23/2005] [Indexed: 11/26/2022]
Abstract
A series of 1,8-naphthyridine derivatives bearing various substituents in position 3, 4, and 7 of the heterocyclic nucleus have been synthesized and evaluated for their affinity at the bovine and human adenosine receptors. The new compounds were found to lack the affinity toward A(1)AR, whereas many of them are able to acquire an interesting affinity and selectivity for the A(2A)AR.
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Affiliation(s)
- Clementina Manera
- Dipartimento di Scienze Farmaceutiche, via Bonanno 6, 56126 Pisa, Italy.
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Gessi S, Varani K, Merighi S, Cattabriga E, Pancaldi C, Szabadkai Y, Rizzuto R, Klotz KN, Leung E, Mac Lennan S, Baraldi PG, Borea PA. Expression, Pharmacological Profile, and Functional Coupling of A2BReceptors in a Recombinant System and in Peripheral Blood Cells Using a Novel Selective Antagonist Radioligand, [3H]MRE 2029-F20. Mol Pharmacol 2005; 67:2137-47. [PMID: 15788741 DOI: 10.1124/mol.104.009225] [Citation(s) in RCA: 57] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022] Open
Abstract
In this study, we compared the pharmacological and biochemical characteristics of A(2B) adenosine receptors in recombinant (hA(2B)HEK293 cells) and native cells (neutrophils, lymphocytes) by using a new potent 8-pyrazole xanthine derivative, [(3)H]N-benzo[1,3]dioxol-5-yl-2-[5-(1,3-dipropyl-2,6-dioxo-2,3,6,7-tetrahydro-1H-purin-8-yl)-1-methyl-1H-pyrazol-3-yl-oxy]-acetamide] ([(3)H]MRE 2029-F20), that has high affinity and selectivity for hA(2B) versus hA(1),hA(2A), and hA(3) subtypes. [(3)H]MRE 2029-F20 bound specifically to the hA(2B) receptor stably transfected in human embryonic kidney (HEK) 293 cells with K(D) of 2.8 +/- 0.2 nM and B(max) of 450 +/- 42 fmol/mg of protein. Saturation experiments of [(3)H]MRE 2029-F20 binding in human neutrophils and lymphocytes detected a single high-affinity binding site with K(D) values of 2.4 +/- 0.5 and 2.7 +/- 0.7 nM, respectively, and B(max) values of 79 +/- 10 and 54 +/- 8 fmol/mg of protein, respectively, in agreement with real-time reverse transcription polymerase chain reaction studies showing the presence of A(2B) mRNA. The rank order of potency of typical adenosine ligands with recombinant hA(2B) receptors was consistent with that typically found for interactions with the A(2B) subtype and was also similar in peripheral blood cells. 5'-N-Ethyl-carboxamidoadenosine stimulated cAMP accumulation in both hA(2B)HEK293 and native cells, whereas phospholipase C activation was observed in recombinant receptors and endogenous subtypes expressed in neutrophils but not in lymphocytes. MRE 2029-F20 was revealed to be a potent antagonist in counteracting the agonist effect in both signal transduction pathways. In conclusion, [(3)H]MRE 2029-F20 is a selective and high-affinity radioligand for the hA(2B) adenosine subtype and may be used to quantify A(2B) endogenous receptors. In this work, we demonstrated their presence and functional coupling in neutrophils and lymphocytes that play a role in inflammatory processes in which A(2B) receptors may be involved.
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Affiliation(s)
- Stefania Gessi
- Faculty of Medicine, Department of Clinical and Experimental Medicine, Pharmacology Unit, University of Ferrara, Via Fossato di Mortara 17-19, 44100 Ferrara, Italy
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Gessi S, Varani K, Merighi S, Cattabriga E, Avitabile A, Gavioli R, Fortini C, Leung E, Mac Lennan S, Borea PA. Expression of A3 adenosine receptors in human lymphocytes: up-regulation in T cell activation. Mol Pharmacol 2004; 65:711-9. [PMID: 14978250 DOI: 10.1124/mol.65.3.711] [Citation(s) in RCA: 72] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022] Open
Abstract
The present study investigates mRNA and protein levels of A3 adenosine receptors in resting (R) and activated (A) human lymphocytes. The receptors were evaluated by the antagonist radioligand [3H]5-N-(4-methoxyphenyl-carbamoyl)amino-8-propyl-2(2furyl)-pyrazolo-[4,3e]-1,2,4-triazolo-[1,5-c]-pyrimidine ([3H]MRE 3008F20), which yielded Bmax values of 125 +/- 15 and 225 +/- 23 fmol/mg of protein and KD values of 1.79 +/- 0.30 and 1.85 +/- 0.25 nM in R and A cells, respectively. The protein seems to be induced with remarkable rapidity starting at 15 min and reaches a plateau at 30 min. Western blot assays revealed that the up-regulation of the A3 subtype after lymphocyte activation was caused by an increase in an enriched CD4+ cell fraction. Real-time reverse transcription-polymerase chain reaction experiments confirmed the rapid increase of A3 mRNA after T cell activation. Competition of radioligand binding by adenosine ligands displayed a rank order of potency typical of the A3 subtype. Thermodynamic data indicated that the binding is enthalpy- and entropy-driven in both R and A cells, suggesting that the activation process does not involve, at a molecular level, receptor alterations leading to modifications in the A3-related binding mechanisms. Functionally, the up-regulation of A3 adenosine receptors in A versus R cells corresponded to a potency increase of the A3 agonist N6-(3-iodo-benzyl)-2-chloro-adenosine-5'-N-methyluronamide in inhibiting cAMP accumulation (IC50=1.5 +/- 0.4 and 2.7 +/- 0.3 nM, respectively); this effect was antagonized by MRE 3008F20 (IC50=5.0 +/- 0.3 nM). In conclusion, our results provide, for the first time, an in-depth investigation of A3 receptors in human lymphocytes and demonstrate that, under activating conditions, they are up-regulated and may contribute to the effects triggered by adenosine.
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Affiliation(s)
- Stefania Gessi
- Department of Clinical and Experimental Medicine, Pharmacology Unit, University of Ferrara, Ferrara, Italy
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Varani K, Gessi S, Merighi S, Iannotta V, Cattabriga E, Pancaldi C, Cadossi R, Borea PA. Alteration of A(3) adenosine receptors in human neutrophils and low frequency electromagnetic fields. Biochem Pharmacol 2003; 66:1897-906. [PMID: 14599547 DOI: 10.1016/s0006-2952(03)00454-4] [Citation(s) in RCA: 28] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022]
Abstract
The present study was designed to evaluate the binding and functional characterization of A(3) adenosine receptors in human neutrophils exposed to low frequency, low energy, pulsing electromagnetic fields (PEMFs). Great interest has grown concerning the use of PEMF in the clinical practice for therapeutic purposes strictly correlated with inflammatory conditions. Saturation experiments performed using the high affinity and selective A(3) adenosine antagonist 5N-(4-methoxyphenyl-carbamoyl)amino-8-propyl-2-(2-furyl)pyrazolo-[4,3-e]-1,2,4-triazolo[1,5-c]pyrimidine ([3H]-MRE 3008F20) revealed a single class of binding sites with similar affinity in control and in PEMF treated human neutrophils (K(D)=2.36+/-0.16 and 2.45+/-0.15 nM, respectively). PEMFs treatment revealed that the receptor density was statistically increased (P<0.01) (B(max)=451+/-18 and 736+/-25fmolmg(-1) protein, respectively). Thermodynamic data indicated that [3H]-MRE 3008F20 binding in control and in PEMF-treated human neutrophils was entropy and enthalpy driven. Competition of radioligand binding by the high affinity A(3) receptor agonists, N(6)-(3-iodo-benzyl)-2-chloro-adenosine-5'-N-methyluronamide (Cl-IB-MECA) and N(6)-(3-iodo-benzyl)adenosine-5'-N-methyl-uronamide (IB-MECA), in the absence of PEMFs revealed high and low affinity values similar to those found in the presence of PEMFs. In both experimental conditions, the addition of GTP 100 microM shifted the competition binding curves of the agonists from a biphasic to a monophasic shape. In functional assays Cl-IB-MECA and IB-MECA were able to inhibit cyclic AMP accumulation and their potencies were statistically increased after exposure to PEMFs. These results indicate in human neutrophils treated with PEMFs the presence of significant alterations in the A(3) adenosine receptor density and functionality.
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Affiliation(s)
- Katia Varani
- Department of Clinical and Experimental Medicine, Pharmacology Unit, University of Ferrara, via Fossato di Mortara 17-19, 44100 Ferrara, Italy
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20
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Varani K, Abbracchio MP, Cannella M, Cislaghi G, Giallonardo P, Mariotti C, Cattabriga E, Cattabeni F, Borea PA, Squitieri F, Cattaneo E. Aberrant A2A receptor function in peripheral blood cells in Huntington's disease. FASEB J 2003; 17:2148-50. [PMID: 12958155 DOI: 10.1096/fj.03-0079fje] [Citation(s) in RCA: 68] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
Abstract
A2A adenosine receptors specifically found on striatal medium spiny neurons play a major role in sensory motor function and may also be involved in neuropsychiatric and neurodegenerative disorders. One hypothesis concerning Huntington's disease (HD) proposes that an imbalance of the cortico-striatal pathway, due to the mutation in the HD gene, leads to striatal vulnerability. An A2A receptor dysfunction has been previously demonstrated in striatal cells engineered to express mutant huntingtin. Here we tested whether a similar dysfunction (i.e., the binding and functional parameters of A2A adenosine receptors) is present in peripheral blood cells (platelets, lymphocytes, and neutrophils) of subjects carrying the mutant gene. This study involved 48 heterozygous and three homozygous patients compared with 58 healthy subjects. Moreover, we selected seven at-risk mutation carriers. A2A receptor density and function are substantially increased in peripheral blood cells from both patients and subjects at the presymptomatic stage. In the neutrophils of the three homozygous HD subjects receptor dysfunction was higher than in heterozygotes. These data indicate the existence of an aberrant A2A receptor phenotype in the peripheral blood cells of subjects carrying the HD mutation. Future studies will assess whether this parameter can be exploited as a peripheral biomarker of Huntington's disease.
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Affiliation(s)
- Katia Varani
- Department of Clinical and Experimental Medicine, Pharmacology Unit, University of Ferrara, Italy
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21
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Baraldi PG, Tabrizi MA, Bovero A, Avitabile B, Preti D, Fruttarolo F, Romagnoli R, Varani K, Borea PA. Recent developments in the field of A2A and A3 adenosine receptor antagonists. Eur J Med Chem 2003; 38:367-82. [PMID: 12750024 DOI: 10.1016/s0223-5234(03)00042-4] [Citation(s) in RCA: 30] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022]
Abstract
In the last years adenosine receptors have been extensively studied, and mainly at present we understand the importance of A(2A) and A(3) adenosine receptors. A(2A) selective adenosine receptors antagonists are promising new drugs for the treatment of Parkinson's disease, while A(3) selective adenosine receptors antagonists have been postulated as novel anti-inflammatory and antiallergic agents; recent studies also indicated a possible employment of these derivatives as antitumour agents. Lately different classes of compounds have been identified as potent A(2A) and A(3) antagonists. In this article we report the past and present efforts which led to development of more potent and selective A(2A) and A(3) antagonists. Our group has mainly worked on the pyrazolo[4,3-e]-1,2,4-triazolo[1,5-c]pyrimidine nucleus both as A(2A) and A(3) antagonists, aiming to improve the affinity, selectivity and the hydrophilic profile. In fact, we have synthesised several compounds endowed with high affinity and selectivity versus A(2A) adenosine receptors, as 2, 2a-c (K(i)A(2A)=0.12-0.19 nM), or A(3) adenosine receptors, as 4p (K(i)A(3)=0.01 nM) and 4q (K(i)A(3)=0.04 nM).
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Affiliation(s)
- Pier Giovanni Baraldi
- Dipartimento di Scienze Farmaceutiche, Università di Ferrara, Via fossato di Mortara 17-19, 44100, Ferrara, Italy.
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22
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Varani K, Laghi-Pasini F, Camurri A, Capecchi PL, Maccherini M, Diciolla F, Ceccatelli L, Lazzerini PE, Ulouglu C, Cattabeni F, Borea PA, Abbracchio MP. Changes of peripheral A2A adenosine receptors in chronic heart failure and cardiac transplantation. FASEB J 2003; 17:280-2. [PMID: 12475889 DOI: 10.1096/fj.02-0543fje] [Citation(s) in RCA: 76] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
Abstract
Peripheral blood mononuclear cells of chronic heart failure (CHF) patients produce great amounts of pro-inflammatory cytokines, indicating that circulating cells are activated and could mirror changes occurring in inflammatory cells infiltrating the failing heart. Adenosine is a regulatory metabolite acting through four membrane receptors that are linked to adenylyl cyclase: activation of the A2A receptor subtype has been reported to inhibit cytokine release. Changes of the adenosinergic system may play a role in CHF development. Here we report an increase of A2A receptor expression, density, and coupling to adenylyl cyclase in blood circulating cells of CHF patients. A2A receptor up-regulation was also found in the explanted hearts of these patients, suggesting that changes of peripheral adenosine receptors mirror changes occurring in the disease target organ. In a cohort of patients followed longitudinally after heart transplantation, alterations of peripheral A2A adenosine receptor progressively normalized to control values within 6 months, suggesting that improvement of cardiac performance is accompanied by progressive restoration of a normal adenosinergic system. These results validate the importance of the A2A receptor in human diseases characterized by a marked inflammatory/immune component and suggest that the evaluation of this receptor in peripheral blood cells may be useful for monitoring hemodynamic changes and the efficacy of pharmacological and non-pharmacological treatments in CHF patients.
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Affiliation(s)
- Katia Varani
- Department of Clinical and Experimental Medicine, Institute of Pharmacology and Interdisciplinary Centre for the Study of Inflammation, University of Ferrara, Ferrara, Italy
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23
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Varani K, Manfredini R, Iannotta V, Pancaldi C, Cattabriga E, Uluoglu C, Borea PA, Portaluppi F. Effects of doxazosin and propranolol on A2A adenosine receptors in essential hypertension. Hypertension 2002; 40:909-13. [PMID: 12468578 DOI: 10.1161/01.hyp.0000039505.79741.15] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
Abstract
A2A adenosine receptors inhibit neutrophil adhesion and superoxide anion generation. The aim of the present study was to evaluate the effect of antihypertensive treatment with doxazosin or propranolol on the binding and functional parameters of A2A adenosine receptors of lymphocytes and neutrophils in essential hypertensive patients. Two groups of previously untreated, essential hypertensive patients were studied. The mean affinity (K(d)) and density (B(max)) of adenosine receptors, by the A2A selective radioligand [3H]-ZM-241385 binding assays, and EC50, by cAMP assays, were obtained first on no medication and a second time after treatment for up to 13 weeks with doxazosin (13 patients) or propranolol (8 patients). A third group of 15 healthy normotensive volunteers matched by age, sex, and body mass index was used as a control. Binding and functional parameters of the A2A adenosine receptors were significantly higher in the 2 hypertensive groups than in controls (P always <0.0001), both in lymphocyte and neutrophil membranes. After treatment with propranolol, the binding parameters did not change significantly, whereas after treatment with doxazosin, K(d), B(max), and EC50 values returned to control levels. In never-treated essential hypertensive patients, lower affinity, higher density, and impaired function of A2A adenosine receptors are present. The binding and functional parameters of A2A adenosine receptors appear to be normalized after treatment with doxazosin but not with propranolol.
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Affiliation(s)
- Katia Varani
- Pharmacology Unit, Department of Clinical and Experimental Medicine, University of Ferrara, Ferrara, Italy
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24
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Varani K, Gessi S, Merighi S, Iannotta V, Cattabriga E, Spisani S, Cadossi R, Borea PA. Effect of low frequency electromagnetic fields on A2A adenosine receptors in human neutrophils. Br J Pharmacol 2002; 136:57-66. [PMID: 11976268 PMCID: PMC1762120 DOI: 10.1038/sj.bjp.0704695] [Citation(s) in RCA: 103] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022] Open
Abstract
The present study describes the effect of low frequency, low energy, pulsing electromagnetic fields (PEMFs) on A2A adenosine receptors in human neutrophils. Saturation experiments performed using a high affinity adenosine antagonist [3H]-ZM 241385 revealed a single class of binding sites in control and in PEMF-treated human neutrophils with similar affinity (KD=1.05+/-0.10 and 1.08+/-0.12 nM, respectively). Furthermore, after 1 h of exposure to PEMFs the receptor density was statistically increased (P<0.01) (Bmax =126+/-10 and 215+/-15 fmol mg-1 protein, respectively). The effect of PEMFs was specific to the A2A adenosine receptors. This effect was also intensity, time and temperature dependent. In the adenylyl cyclase assays the A2A receptor agonists, HE-NECA and NECA, increased cyclic AMP accumulation in untreated human neutrophils with an EC50 value of 43 (40 - 47) and 255 (228 - 284) nM, respectively. The capability of HE-NECA and NECA to stimulate cyclic AMP levels in human neutrophils was increased (P<0.01) after exposure to PEMFs with an EC50 value of 10(8 - 13) and 61(52 - 71) nM, respectively. In the superoxide anion (O2-) production assays HE-NECA and NECA inhibited the generation of O2- in untreated human neutrophils, with an EC50 value of 3.6(3.1 - 4.2) and of 23(20 - 27) nM, respectively. Moreover, in PEMF-treated human neutrophils, the same compounds show an EC50 value of 1.6(1.2 - 2.1) and of 6.0(4.7 - 7.5) nM respectively. These results indicate the presence of significant alterations in the expression and in the functionality of adenosine A2A receptors in human neutrophils treated with PEMFs.
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MESH Headings
- Binding, Competitive
- Cyclic AMP/biosynthesis
- Electromagnetic Fields
- Humans
- In Vitro Techniques
- Kinetics
- Neutrophils/metabolism
- Neutrophils/radiation effects
- Purinergic P1 Receptor Agonists
- Radioligand Assay
- Receptor, Adenosine A2A
- Receptors, Adrenergic, alpha-2/metabolism
- Receptors, Adrenergic, beta-2/metabolism
- Receptors, Opioid, kappa/metabolism
- Receptors, Opioid, mu/metabolism
- Receptors, Purinergic P1/metabolism
- Superoxides/metabolism
- Temperature
- Time Factors
- Up-Regulation
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Affiliation(s)
- Katia Varani
- Department of Clinical and Experimental Medicine, Pharmacology Unit, University of Ferrara, Ferrara, Italy
| | - Stefania Gessi
- Department of Clinical and Experimental Medicine, Pharmacology Unit, University of Ferrara, Ferrara, Italy
| | - Stefania Merighi
- Department of Clinical and Experimental Medicine, Pharmacology Unit, University of Ferrara, Ferrara, Italy
| | - Valeria Iannotta
- Department of Clinical and Experimental Medicine, Pharmacology Unit, University of Ferrara, Ferrara, Italy
| | - Elena Cattabriga
- Department of Clinical and Experimental Medicine, Pharmacology Unit, University of Ferrara, Ferrara, Italy
| | - Susanna Spisani
- Department of Biochemistry and Molecular Biology, University of Ferrara, Ferrara, Italy
| | | | - Pier Andrea Borea
- Department of Clinical and Experimental Medicine, Pharmacology Unit, University of Ferrara, Ferrara, Italy
- Author for correspondence:
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Merighi S, Varani K, Gessi S, Cattabriga E, Iannotta V, Ulouglu C, Leung E, Borea PA. Pharmacological and biochemical characterization of adenosine receptors in the human malignant melanoma A375 cell line. Br J Pharmacol 2001; 134:1215-26. [PMID: 11704641 PMCID: PMC1573044 DOI: 10.1038/sj.bjp.0704352] [Citation(s) in RCA: 94] [Impact Index Per Article: 4.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022] Open
Abstract
1. The present work characterizes, from a pharmacological and biochemical point of view, adenosine receptors in the human malignant melanoma A375 cell line. 2. Adenosine receptors were detected by RT - PCR experiments. A1 receptors were characterized using [3H]-DPCPX binding with a KD of 1.9+/-0.2 nM and Bmax of 23+/-7 fmol x mg(-1) of protein. A2A receptors were studied with [3H]-SCH 58261 binding and revealed a KD of 5.1+/-0.2 nM and a Bmax of 220+/-7 fmol x mg(-1) of protein. A3 receptors were studied with the new A3 adenosine receptor antagonist [3H]-MRE 3008F20, the only A3 selective radioligand currently available. Saturation experiments revealed a single high affinity binding site with KD of 3.3+/-0.7 nM and Bmax of 291+/-50 fmol x mg(-1) of protein. 3. The pharmacological profile of radioligand binding on A375 cells was established using typical adenosine ligands which displayed a rank order of potency typical of the different adenosine receptor subtype. 4. Thermodynamic data indicated that radioligand binding to adenosine receptor subtypes in A375 cells was entropy- and enthalpy-driven. 5. In functional assays the high affinity A2A agonists HE-NECA, CGS 21680 and A2A - A2B agonist NECA were able to increase cyclic AMP accumulation in A375 cells whereas A3 agonists Cl-IB-MECA, IB-MECA and NECA were able to stimulate Ca2+ mobilization. In conclusion, all these data indicate, for the first time, that adenosine receptors with a pharmacological and biochemical profile typical of the A1, A2A, A2B and A3 receptor subtype are present on A375 melanoma cell line.
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Affiliation(s)
- Stefania Merighi
- Department of Clinical and Experimental Medicine, Pharmacology Unit, University of Ferrara, Centro Nazionale Di Eccellenza Per Lo Sviluppo Di Metodologie Innovative Per Lo Studio Ed Il Trattamento Delle Patologie Infiammatorie, Italy
| | - Katia Varani
- Department of Clinical and Experimental Medicine, Pharmacology Unit, University of Ferrara, Centro Nazionale Di Eccellenza Per Lo Sviluppo Di Metodologie Innovative Per Lo Studio Ed Il Trattamento Delle Patologie Infiammatorie, Italy
| | - Stefania Gessi
- Department of Clinical and Experimental Medicine, Pharmacology Unit, University of Ferrara, Centro Nazionale Di Eccellenza Per Lo Sviluppo Di Metodologie Innovative Per Lo Studio Ed Il Trattamento Delle Patologie Infiammatorie, Italy
| | - Elena Cattabriga
- Department of Clinical and Experimental Medicine, Pharmacology Unit, University of Ferrara, Centro Nazionale Di Eccellenza Per Lo Sviluppo Di Metodologie Innovative Per Lo Studio Ed Il Trattamento Delle Patologie Infiammatorie, Italy
| | - Valeria Iannotta
- Department of Clinical and Experimental Medicine, Pharmacology Unit, University of Ferrara, Centro Nazionale Di Eccellenza Per Lo Sviluppo Di Metodologie Innovative Per Lo Studio Ed Il Trattamento Delle Patologie Infiammatorie, Italy
| | - Canan Ulouglu
- Department of Pharmacology, Gazi University, Medical Faculty, Ankara, Turkey
| | - Edward Leung
- King Pharmaceuticals, Cary, North Carolina, U.S.A
| | - Pier Andrea Borea
- Department of Clinical and Experimental Medicine, Pharmacology Unit, University of Ferrara, Centro Nazionale Di Eccellenza Per Lo Sviluppo Di Metodologie Innovative Per Lo Studio Ed Il Trattamento Delle Patologie Infiammatorie, Italy
- Author for correspondence:
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26
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Varani K, Rigamonti D, Sipione S, Camurri A, Borea PA, Cattabeni F, Abbracchio MP, Cattaneo E. Aberrant amplification of A
2A
receptor signaling in striatal cells expressing mutant huntingtin. FASEB J 2001. [DOI: 10.1096/fj.00-0730fje] [Citation(s) in RCA: 72] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
Affiliation(s)
- Katia Varani
- Dipartimento di Medicina Clinica Sperimentale Universita’ di Ferrara Via Fossato di Mortara 17/19 44100 Ferrara Italy
| | - Dorotea Rigamonti
- Institute of Pharmacological Sciences University of Milano Via Balzaretti 9 20133 Milano Italy
| | - Simonetta Sipione
- Institute of Pharmacological Sciences University of Milano Via Balzaretti 9 20133 Milano Italy
| | - Alessandra Camurri
- Institute of Pharmacological Sciences University of Milano Via Balzaretti 9 20133 Milano Italy
| | - Pier Andrea Borea
- Institute of Pharmacological Sciences University of Milano Via Balzaretti 9 20133 Milano Italy
| | - Flaminio Cattabeni
- Institute of Pharmacological Sciences University of Milano Via Balzaretti 9 20133 Milano Italy
| | - Maria P. Abbracchio
- Institute of Pharmacological Sciences University of Milano Via Balzaretti 9 20133 Milano Italy
| | - Elena Cattaneo
- Institute of Pharmacological Sciences University of Milano Via Balzaretti 9 20133 Milano Italy
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27
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Ceruti S, Franceschi C, Barbieri D, Malorni W, Camurri A, Giammarioli AM, Ambrosini A, Racagni G, Cattabeni F, Abbracchio MP. Apoptosis induced by 2-chloro-adenosine and 2-chloro-2'-deoxy-adenosine in a human astrocytoma cell line: differential mechanisms and possible clinical relevance. J Neurosci Res 2000; 60:388-400. [PMID: 10797542 DOI: 10.1002/(sici)1097-4547(20000501)60:3<388::aid-jnr14>3.0.co;2-v] [Citation(s) in RCA: 37] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/08/2022]
Abstract
We have previously demonstrated that 2-chloro-adenosine (2-CA) can induce apoptosis of rat astroglial cells (Abbracchio et al. [1995] Biochem. Biophys. Res. Commun. 213:908-915). In the present study, we have characterized, for the first time, the effects induced on a human astrocytoma cell line (ADF cells) by both 2-CA and its related analog 2-chloro-2'-deoxy-adenosine (2-CdA, that is employed as anti-cancer agent in chronic lymphoid malignancies). Exposure of these cells to either adenosine analog resulted in time- and concentration-dependent apoptosis. Experiments with pharmacological agents known to interfere with adenosine receptors, its membrane transporter, and intracellular nucleoside kinases showed that: (i) cell death induced by either adenosine analog did not depend on extracellular adenosine receptors, but on a direct intracellular action; however, only in the case of 2-CA, was entry into cells mediated by the specific nitrobenzyl-tioinosine-sensitive transporter; (ii) for both adenosine analogs, induction of apoptosis required the phosphorylation/activation by specific intracellular nucleoside kinases, i.e., adenosine kinase for 2-CA, and deoxycytidine kinase for 2-CdA. In addition, only in the case of 2-CdA, was induction of apoptosis preceded by a block of cells at the G2/M phase of the cell cycle. Finally, at concentrations of either analog that killed about 80-90% of astrocytoma cells, a significantly lower effect on the viability of primary cortical neurons was observed. In conclusion, both adenosine analogs can trigger apoptosis of human astrocytoma cells, albeit with different mechanisms. This effect together with the relative sparing of neuronal cells, may have potential clinical implications for the therapy of tumors of glial origin.
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Affiliation(s)
- S Ceruti
- Institute of Pharmacological Science, University of Milan, Milan, Italy
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28
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Gessi S, Varani K, Merighi S, Ongini E, Borea PA. A(2A) adenosine receptors in human peripheral blood cells. Br J Pharmacol 2000; 129:2-11. [PMID: 10694196 PMCID: PMC1621134 DOI: 10.1038/sj.bjp.0703045] [Citation(s) in RCA: 125] [Impact Index Per Article: 5.2] [Reference Citation Analysis] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/30/1999] [Revised: 09/10/1999] [Accepted: 10/20/1999] [Indexed: 11/08/2022] Open
Affiliation(s)
- S Gessi
- Department of Clinical and Experimental Medicine, Pharmacology Unit, University of Ferrara, Via Fossato di Mortara 17-19, 44100 Ferrara, Italy
| | - K Varani
- Department of Clinical and Experimental Medicine, Pharmacology Unit, University of Ferrara, Via Fossato di Mortara 17-19, 44100 Ferrara, Italy
| | - S Merighi
- Department of Clinical and Experimental Medicine, Pharmacology Unit, University of Ferrara, Via Fossato di Mortara 17-19, 44100 Ferrara, Italy
| | - E Ongini
- Schering-Plough Research Institute, San Raffaele Science Park, 20132 Milan, Italy
| | - P A Borea
- Department of Clinical and Experimental Medicine, Pharmacology Unit, University of Ferrara, Via Fossato di Mortara 17-19, 44100 Ferrara, Italy
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Abstract
Recent studies indicate a widening role for adenosine receptors in many therapeutic areas. Adenosine receptors are involved in immunological and inflammatory responses, respiratory regulation, the cardiovascular system, the kidney, various CNS-mediated events including sleep and neuroprotection, as well as central and peripheral pain processes. In this review, the physiological role of adenosine receptors in these key areas is described with reference to the therapeutic potential of adenosine receptor agonists and antagonists.
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Affiliation(s)
- SM Kaiser
- AstraZeneca R & D Griffith University, Brisbane 4111, Australia
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30
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32
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Varani K, Gessi S, Dionisotti S, Ongini E, Borea PA. [3H]-SCH 58261 labelling of functional A2A adenosine receptors in human neutrophil membranes. Br J Pharmacol 1998; 123:1723-31. [PMID: 9605581 PMCID: PMC1565317 DOI: 10.1038/sj.bjp.0701758] [Citation(s) in RCA: 51] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/07/2023] Open
Abstract
1. The present study describes the direct labelling of A2A adenosine receptors in human neutrophil membranes with the potent and selective antagonist radioligand, [3H]-5-amino-7-(2-phenylethyl)-2-(2-furyl)-pyrazolo[4,3-e]-1,2,4 triazolo[l,5-c]pyrimidine, ([3H]-SCH 58261). In addition, both receptor affinity and potency of a number of adenosine receptor agonists and antagonists were determined in binding, adenylyl cyclase and superoxide anion production assays. 2. Saturation experiments revealed a single class of binding sites with Kd and Bmax values of 1.34 nM and 75 fmol mg(-1) protein, respectively. Adenosine receptor ligands competed for the binding of 1 nM [3H]-SCH 58261 to human neutrophil membranes, with a rank order of potency consistent with that typically found for interactions with the A2A adenosine receptors. In the adenylyl cyclase and in the superoxide anion production assays the same compounds exhibited a rank order of potency identical to that observed in binding experiments. 3. Thermodynamic data indicated that [3H]-SCH 58261 binding to human neutrophils is entropy and enthalpy-driven. This finding is in agreement with the thermodynamic behaviour of antagonists binding to rat striatal A2A adenosine receptors. 4. It was concluded that in human neutrophil membranes, [3H]-SCH 58261 directly labels binding sites with pharmacological properties similar to those of A2A adenosine receptors of other tissues. The receptors labelled by [3H]-SCH 58261 mediated the effects of adenosine and adenosine receptor agonists to stimulate cyclic AMP accumulation and inhibition of superoxide anion production in human neutrophils.
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Affiliation(s)
- K Varani
- Department of Clinical and Experimental Medicine, University of Ferrara, Italy
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33
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