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Figarella K, Kim J, Ruan W, Mills T, Eltzschig HK, Yuan X. Hypoxia-adenosine axis as therapeutic targets for acute respiratory distress syndrome. Front Immunol 2024; 15:1328565. [PMID: 38312838 PMCID: PMC10835146 DOI: 10.3389/fimmu.2024.1328565] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/30/2023] [Accepted: 01/03/2024] [Indexed: 02/06/2024] Open
Abstract
The human respiratory and circulatory systems collaborate intricately to ensure oxygen delivery to all cells, which is vital for ATP production and maintaining physiological functions and structures. During limited oxygen availability, hypoxia-inducible factors (HIFs) are stabilized and play a fundamental role in maintaining cellular processes for hypoxia adaptation. First discovered during investigations of erythropoietin production regulation, HIFs influence physiological and pathological processes, including development, inflammation, wound healing, and cancer. HIFs promote extracellular adenosine signaling by enhancing adenosine generation and receptor signaling, representing an endogenous feedback mechanism that curbs excessive inflammation, supports injury resolution, and enhances hypoxia tolerance. This is especially important for conditions that involve tissue hypoxia, such as acute respiratory distress syndrome (ARDS), which globally poses significant health challenges without specific treatment options. Consequently, pharmacological strategies to amplify HIF-mediated adenosine production and receptor signaling are of great importance.
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Affiliation(s)
- Katherine Figarella
- Department of Anesthesiology, Critical Care and Pain Medicine, University of Texas Health Science Center at Houston, Houston, TX, United States
| | - Jieun Kim
- Department of Anesthesiology, Critical Care and Pain Medicine, University of Texas Health Science Center at Houston, Houston, TX, United States
| | - Wei Ruan
- Department of Anesthesiology, Critical Care and Pain Medicine, University of Texas Health Science Center at Houston, Houston, TX, United States
- Department of Anesthesiology, The Second Xiangya Hospital, Central South University, Changsha, Hunan, China
| | - Tingting Mills
- Department of Biochemistry and Molecular Biology, University of Texas Health Science Center at Houston, Houston, TX, United States
| | - Holger Klaus Eltzschig
- Department of Anesthesiology, Critical Care and Pain Medicine, University of Texas Health Science Center at Houston, Houston, TX, United States
| | - Xiaoyi Yuan
- Department of Anesthesiology, Critical Care and Pain Medicine, University of Texas Health Science Center at Houston, Houston, TX, United States
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2
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Diversifying the xanthine scaffold for potential phosphodiesterase 9A inhibitors: synthesis and validation. Med Chem Res 2021. [DOI: 10.1007/s00044-021-02722-9] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/21/2022]
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3
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Zhang D, Wang Y, Lin H, Sun Y, Wang M, Jia Y, Yu X, Jiang H, Xu W, Sun JP, Xu Z. Function and therapeutic potential of G protein-coupled receptors in epididymis. Br J Pharmacol 2020; 177:5489-5508. [PMID: 32901914 DOI: 10.1111/bph.15252] [Citation(s) in RCA: 13] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/20/2020] [Revised: 08/08/2020] [Accepted: 09/03/2020] [Indexed: 12/14/2022] Open
Abstract
Infertility rates for both females and males have increased continuously in recent years. Currently, effective treatments for male infertility with defined mechanisms or targets are still lacking. G protein-coupled receptors (GPCRs) are the largest class of drug targets, but their functions and the implications for the therapeutic development for male infertility largely remain elusive. Nevertheless, recent studies have shown that several members of the GPCR superfamily play crucial roles in the maintenance of ion-water homeostasis of the epididymis, development of the efferent ductules, formation of the blood-epididymal barrier and maturation of sperm. Knowledge of the functions, genetic variations and working mechanisms of such GPCRs, along with the drugs and ligands relevant to their specific functions, provide future directions and a great arsenal for new developments in the treatment of male infertility.
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Affiliation(s)
- Daolai Zhang
- Department of Pharmaceutical Sciences, Binzhou Medical University, Yantai, China.,Key Laboratory Experimental Teratology of the Ministry of Education and Department of Biochemistry and Molecular Biology, School of Medicine, Shandong University, Jinan, China
| | - Yanfei Wang
- Shandong Provincial Key Laboratory of Animal Cells and Developmental Biology, School of Life Sciences, Shandong University, Qingdao, China
| | - Hui Lin
- Key Laboratory Experimental Teratology of the Ministry of Education and Department of Biochemistry and Molecular Biology, School of Medicine, Shandong University, Jinan, China
| | - Yujing Sun
- Key Laboratory Experimental Teratology of the Ministry of Education and Department of Biochemistry and Molecular Biology, School of Medicine, Shandong University, Jinan, China
| | - Mingwei Wang
- Key Laboratory Experimental Teratology of the Ministry of Education and Department of Biochemistry and Molecular Biology, School of Medicine, Shandong University, Jinan, China
| | - Yingli Jia
- Department of Physiology and Pathophysiology, School of Basic Medical Sciences, Key Laboratory of Molecular Cardiovascular Science, Ministry of Education, Peking University, Beijing, China
| | - Xiao Yu
- Department of Physiology, School of Medicine, Shandong University, Jinan, China
| | - Hui Jiang
- Department of Urology, Peking University Third Hospital, Beijing, China.,Department of Reproductive Medicine Center, Peking University Third Hospital, Beijing, China
| | - Wenming Xu
- Joint Laboratory of Reproductive Medicine, SCU-CUHK, Key Laboratory of Obstetric, Gynecologic and Pediatric Diseases and Birth Defects of Ministry of Education, Sichuan University West China Second University Hospital, Chengdu, China
| | - Jin-Peng Sun
- Department of Pharmaceutical Sciences, Binzhou Medical University, Yantai, China.,Key Laboratory Experimental Teratology of the Ministry of Education and Department of Biochemistry and Molecular Biology, School of Medicine, Shandong University, Jinan, China.,Department of Physiology and Pathophysiology, School of Basic Medical Sciences, Key Laboratory of Molecular Cardiovascular Science, Ministry of Education, Peking University, Beijing, China
| | - Zhigang Xu
- Shandong Provincial Key Laboratory of Animal Cells and Developmental Biology, School of Life Sciences, Shandong University, Qingdao, China.,Shandong Provincial Collaborative Innovation Center of Cell Biology, Shandong Normal University, Jinan, China
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Vanda D, Zajdel P, Soural M. Imidazopyridine-based selective and multifunctional ligands of biological targets associated with psychiatric and neurodegenerative diseases. Eur J Med Chem 2019; 181:111569. [DOI: 10.1016/j.ejmech.2019.111569] [Citation(s) in RCA: 25] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/21/2019] [Revised: 06/26/2019] [Accepted: 07/28/2019] [Indexed: 12/18/2022]
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Gorain B, Choudhury H, Yee GS, Bhattamisra SK. Adenosine Receptors as Novel Targets for the Treatment of Various Cancers. Curr Pharm Des 2019; 25:2828-2841. [DOI: 10.2174/1381612825666190716102037] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/30/2019] [Accepted: 07/01/2019] [Indexed: 01/28/2023]
Abstract
Adenosine is a ubiquitous signaling nucleoside molecule, released from different cells within the body
to act on vasculature and immunoescape. The physiological action on the proliferation of tumour cell has been
reported by the presence of high concentration of adenosine within the tumour microenvironment, which results
in the progression of the tumour, even leading to metastases. The activity of adenosine exclusively depends upon
the interaction with four subtypes of heterodimeric G-protein-coupled adenosine receptors (AR), A1, A2A, A2B,
and A3-ARs on the cell surface. Research evidence supports that the activation of those receptors via specific
agonist or antagonist can modulate the proliferation of tumour cells. The first category of AR, A1 is known to play
an antitumour activity via tumour-associated microglial cells to prevent the development of glioblastomas.
A2AAR are found in melanoma, lung, and breast cancer cells, where tumour proliferation is stimulated due to
inhibition of the immune response via inhibition of natural killer cells cytotoxicity, T cell activity, and tumourspecific
CD4+/CD8+ activity. Alternatively, A2BAR helps in the development of tumour upon activation via
upregulation of angiogenin factor in the microvascular endothelial cells, inhibition of MAPK and ERK 1/2 phosphorylation
activity. Lastly, A3AR is expressed in low levels in normal cells whereas the expression is upregulated
in tumour cells, however, agonists to this receptor inhibit tumour proliferation through modulation of Wnt
and NF-κB signaling pathways. Several researchers are in search for potential agents to modulate the overexpressed
ARs to control cancer. Active components of A2AAR antagonists and A3AR agonists have already entered
in Phase-I clinical research to prove their safety in human. This review focused on novel research targets towards
the prevention of cancer progression through stimulation of the overexpressed ARs with the hope to protect lives
and advance human health.
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Affiliation(s)
- Bapi Gorain
- School of Pharmacy, Faculty of Health and Medical Science, Taylor’s University, Subang Jaya, Selangor, Malaysia
| | - Hira Choudhury
- Department of Pharmaceutical Technology, School of Pharmacy, International Medical University, Bukit Jalil 57000, Kuala Lumpur, Malaysia
| | - Gan Sook Yee
- Department of Life Sciences, School of Pharmacy, International Medical University, Bukit Jalil 57000, Kuala Lumpur, Malaysia
| | - Subrat Kumar Bhattamisra
- Department of Life Sciences, School of Pharmacy, International Medical University, Bukit Jalil 57000, Kuala Lumpur, Malaysia
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Singh N, Shreshtha AK, Thakur M, Patra S. Xanthine scaffold: scope and potential in drug development. Heliyon 2018; 4:e00829. [PMID: 30302410 PMCID: PMC6174542 DOI: 10.1016/j.heliyon.2018.e00829] [Citation(s) in RCA: 63] [Impact Index Per Article: 10.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/21/2018] [Revised: 09/25/2018] [Accepted: 09/25/2018] [Indexed: 02/07/2023] Open
Abstract
Medicinal plants have been the basis for discovery of various important marketed drugs. Xanthine is one such lead molecule. Xanthines in various forms (caffeine, theophylline, theobromine, etc) are abode in tea, coffee, cocoa, chocolate etc. giving them popular recognition. These compounds are best known for their diverse pharmaceutical applications as cyclic nucleotide phosphodiesterase inhibition, antagonization of adenosine receptor, anti-inflammatory, anti-microbial, anti-oxidant and anti-tumor activities. These properties incentivize to use xanthine as scaffold to develop new derivatives. Chemical synthesis contributes greater diversity in xanthine based derivatisation. With highlighting the existing challenges in chemical synthesis, the present review focuses the probable solution to fill existing lacuna. The review summarizes the available knowledge of xanthine based drugs development along with exploring new xanthine led chemical synthesis path for bringing diversification in xanthine based research. The main objective of this review is to explore the immense potential of xanthine as scaffold in drug development.
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Affiliation(s)
- Nivedita Singh
- Department of Biosciences and Bioengineering, Indian Institute of Technology Guwahati, Guwahati 781039, India
| | | | - M.S. Thakur
- Fermentation Technology and Bioengineering Department, Central Food Technological Research Institute, Mysore, India
| | - Sanjukta Patra
- Department of Biosciences and Bioengineering, Indian Institute of Technology Guwahati, Guwahati 781039, India
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7
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Castilhos LG, Adefegha SA, Doleski PH, Bertoldo TM, Moritz CEJ, Casali EA, Leal DB. NTPDase, 5'-nucleotidase and adenosine deaminase activities and purine levels in serum of sickle cell anemia patients. J Appl Biomed 2018. [DOI: 10.1016/j.jab.2017.12.004] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/07/2023] Open
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8
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Neely Wilson C, Batra VK. Lipopolysaccharide binds to and activates A1 adenosine receptors on human pulmonary artery endothelial cells. ACTA ACUST UNITED AC 2016. [DOI: 10.1177/09680519020080040301] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/15/2022]
Abstract
Previously, it was reported that A1 adenosine receptor antagonists prevent endotoxin-inducedacute lung injury and pulmonary arterial endothelial cell damage. In competition radioligand binding experiments in membranes prepared from human pulmonary artery endothelial cells (PAECs), lipopolysaccharides (LPSs) of Escherichia coli, Salmonella typhimurium, Klebsiella pneumoniae, and Pseudomonas aeruginosa displaced the binding of a selective A adenosine receptor antagonist [125I]-BWA844U (IC 50 values: 195 ng/ml, 290 ng/ml, 602 ng/ml, and 6931 ng/ml, respectively)in a dose-dependent, competitive manner. There was no displacement of this radioligand by enterotoxin (≤ 10 μg/ml), diphosphoryl lipid A (≤ 10μg/ml), and glycolipids, monosialoganglioside(≤ 1μg/ml), lactocerebroside (≤ 100μg/ml), or NBD galactocerebroside (≤ 100 μg/ml). Based on calculated IC values, LPS ( E. coli, IC50 111 ng/ml) 50 6 displaced the selective A1 adenosine receptor agonist, [3H]-2-chloro, N -cyclopentyladenosine (CCPA) in human PAECs with a potency profile, CCPA > LPS > 2-phenylaminoadenosine (CV 1808), a selective A2 adenosine receptor agonist. The potency profile for displacement of the selective A μ 2a adenosine receptor agonist [ 3H]-CGS 21680 was CV 1808 > CCPA. LPS ( E. coli 0.1 pg/ml—10 g/ml) did not displace [3H]-CGS 21680 binding. In human PAECs, IL-6 and TXA2 release induced by LPS (0—1 μg/ml) or CCPA (0—1 μM) at high doses was significantly reduced by the selective A1 adenosine receptor antagonist, 8-cyclopentyl-1,3-dipropylxanthine(DPCPX; 1 μM). These data suggest that LPS binds to and activates A1 adenosine receptors on human PAECs to induce the release of IL-6 and TXA 2. Activation of A1 adenosine receptors on human PAECs by LPS, may contribute to the pathophysiology of acute lung injury associated with Gram-negative septicemia and endotoxemia.
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Affiliation(s)
| | - Vinod K. Batra
- Endacea, Inc., Research Triangle Park, North Carolina, USA
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9
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Johnston-Cox HA, Koupenova M, Ravid K. A2 adenosine receptors and vascular pathologies. Arterioscler Thromb Vasc Biol 2012; 32:870-8. [PMID: 22423039 PMCID: PMC5755359 DOI: 10.1161/atvbaha.112.246181] [Citation(s) in RCA: 35] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/19/2012] [Accepted: 02/14/2012] [Indexed: 12/20/2022]
Abstract
Cardiovascular disease, a leading cause of death and morbidity, is regulated, among various factors, by inflammation. The level of the metabolite adenosine is augmented under stress, including inflammatory, hypoxic, or injurious events. Adenosine has been shown to affect various physiological and pathological processes, largely through 1 or more of its 4 types of receptors: the A1 and A3 adenylyl cyclase inhibitory receptors and the A2A and A2B adenylyl cyclase stimulatory receptors. This article focuses on reviewing common and distinct effects of the 2 A2-type adenosine receptors on vascular disease and the mechanisms involved. Understanding the pathogenesis of vascular disease mediated by these receptors is important to the development of therapeutics and to the prevention and management of disease.
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Affiliation(s)
- Hillary A. Johnston-Cox
- Departments of Medicine and Biochemistry, Whitaker Cardiovascular Institute, and Evans Center for Interdisciplinary Biomedical Research, Boston University School of Medicine, Boston, MA 02118
| | - Milka Koupenova
- Departments of Medicine and Biochemistry, Whitaker Cardiovascular Institute, and Evans Center for Interdisciplinary Biomedical Research, Boston University School of Medicine, Boston, MA 02118
| | - Katya Ravid
- Departments of Medicine and Biochemistry, Whitaker Cardiovascular Institute, and Evans Center for Interdisciplinary Biomedical Research, Boston University School of Medicine, Boston, MA 02118
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10
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Johnston-Cox HA, Ravid K. Adenosine and blood platelets. Purinergic Signal 2011; 7:357-65. [PMID: 21484090 DOI: 10.1007/s11302-011-9220-4] [Citation(s) in RCA: 69] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/16/2010] [Accepted: 01/19/2011] [Indexed: 02/07/2023] Open
Abstract
Adenosine is an important regulatory metabolite and an inhibitor of platelet activation. Adenosine released from different cells or generated through the activity of cell-surface ectoenzymes exerts its effects through the binding of four different G-protein-coupled adenosine receptors. In platelets, binding of A(2) subtypes (A(2A) or A(2B)) leads to consequent elevation of intracellular cyclic adenosine monophosphate, an inhibitor of platelet activation. The significance of this ligand and its receptors for platelet activation is addressed in this review, including how adenosine metabolism and its A(2) subtype receptors impact the expression and activity of adenosine diphosphate receptors. The expression of A(2) adenosine receptors is induced by conditions such as oxidative stress, a hallmark of aging. The effect of adenosine receptors on platelet activation during aging is also discussed, as well as potential therapeutic applications.
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Affiliation(s)
- Hillary A Johnston-Cox
- Departments of Medicine and Biochemistry, Whitaker Cardiovascular Institute, and Evans Center for Interdisciplinary Biomedical Research, Boston University School of Medicine, CVI, 700 Albany St., Boston, MA, 02118, USA
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O'Malley MA, Naranjo AN, Lazarova T, Robinson AS. Analysis of adenosine A₂a receptor stability: effects of ligands and disulfide bonds. Biochemistry 2010; 49:9181-9. [PMID: 20853839 DOI: 10.1021/bi101155r] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/01/2023]
Abstract
G protein-coupled receptors (GPCRs) constitute the largest family of integral membrane proteins present in all eukaryotic cells, yet relatively little information about their structure, folding, and stability has been published. In this work, we describe several approaches to characterizing the conformational stability of the human adenosine A(2)a receptor (hA(2)aR). Thermal denaturation and chemical denaturation were not reversible, yet clear differences in the unfolding behavior were observed upon ligand binding via circular dichroism and fluorescence spectrometry. We found that the stability of hA(2)aR was increased upon incubation with the agonist N(6)-cyclohexyladenosine or the antagonist theophylline. When extracellular disulfide bonds were reduced with a chemical reducing agent, the ligand binding activity decreased by ~40%, but reduction of these bonds did not compromise the unfolding transition observed via urea denaturation. Overall, these approaches offer a general strategy for characterizing the effect of surfactant and ligand effects on the stability of GPCRs.
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Affiliation(s)
- Michelle A O'Malley
- Department of Chemical Engineering, University of Delaware, 150 Academy Street, Newark, DE 19716, USA
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Nagarajan S, Arjun P, Raaman N, Das TM. Regioselective facile one-pot Friedländer synthesis of sugar-based heterocyclic biomolecules. Carbohydr Res 2010; 345:1988-97. [DOI: 10.1016/j.carres.2010.07.016] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/02/2010] [Accepted: 07/08/2010] [Indexed: 11/24/2022]
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13
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Stowe DF, Boban M, Palmisano BW, Kampine JP, Bosnjak ZJ. Coronary Flow Response to Vasodilators in Isolated Hearts Cold Perfused for One Day with Butanedione Monoxime. ACTA ACUST UNITED AC 2009. [DOI: 10.3109/10623329409024637] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022]
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14
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Nell PG, Albrecht-Küpper B. The adenosine A1 receptor and its ligands. PROGRESS IN MEDICINAL CHEMISTRY 2009; 47:163-201. [PMID: 19328291 DOI: 10.1016/s0079-6468(08)00204-x] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/11/2022]
Affiliation(s)
- Peter G Nell
- Global Drug Discovery - Operations, Bayer HealthCare AG, Bayer Schering Pharma, Müllerstrasse 178, 13353 Berlin, Germany
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15
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Kiesman WF, Elzein E, Zablocki J. A1 adenosine receptor antagonists, agonists, and allosteric enhancers. Handb Exp Pharmacol 2009:25-58. [PMID: 19639278 DOI: 10.1007/978-3-540-89615-9_2] [Citation(s) in RCA: 72] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 05/28/2023]
Abstract
Intense efforts of many pharmaceutical companies and academicians in the A(1) adenosine receptor (AR) field have led to the discovery of clinical candidates that are antagonists, agonists, and allosteric enhancers. The A(1)AR antagonists currently in clinical development are KW3902, BG9928, and SLV320. All three have high affinity for the human (h) A(1)AR subtype (hA(1) K (i) < 10 nM), > 200-fold selectivity over the hA(2A) subtype, and demonstrate renal protective effects in multiple animal models of disease and pharmacologic effects in human subjects. In the A(1)AR agonist area, clinical candidates have been discovered for the following conditions: atrial arrhythmias (tecadenoson, selodenoson and PJ-875); Type II diabetes and insulin sensitizing agents (GR79236, ARA, RPR-749, and CVT-3619); and angina (BAY 68-4986). The challenges associated with the development of any A(1)AR agonist are to obtain tissue-specific effects but avoid off-target tissue side effects and A(1)AR desensitization leading to tachyphylaxis. For the IV antiarrhythmic agents that act as ventricular rate control agents, a selective response can be accomplished by careful IV dosing paradigms. The treatment of type II diabetes using A(1)AR agonists in the clinic has met with limited success due to cardiovascular side effects and a well-defined desensitization of full agonists in human trials (GR79236, ARA, and RPR 749). However, new partial A(1)AR agonists are in development, including CVT-3619 hA(1) AR K(i) = 55nM, hA(2A:hA2B:hA(3))1,000:20, CV Therapeutics), which have the potential to provide enhanced insulin sensitivity without cardiovascular side effects and tachyphylaxis. The nonnucleosidic A(1)AR agonist BAY 68-4986 (capadenoson) represents a novel approach to angina wherein both animal studies and early human studies are promising. T-62 is an A(1)AR allosteric enhancer that is currently being evaluated in clinical trials as a potential treatment for neuropathic pain. The challenges associated with developing A(1)AR antagonists, agonists, or allosteric enhancers for therapeutic intervention are now well defined in humans. Significant progress has been made in identifying A(1)AR antagonists for the treatment of edema associated with congestive heart failure (CHF), A(1)AR agonists for the treatment of atrial arrhythmias, type II diabetes and angina, and A(1)AR allosteric enhancers for the treatment of neuropathic pain.
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Abstract
According to an executive summary of the GINA dissemination committee report, it is now estimated that approximately 300 million people (5% of the global population or 1 in 20 persons) have asthma. Despite the scientific progress made over the past several decades toward improving our understanding of the pathophysiology of asthma, there is still a great need for improved therapies, particularly oral therapies that enhance patient compliance and that target new mechanisms of action. Adenosine is an important signalling molecule in human asthma. By acting on extracellular G-protein-coupled ARs on a number of different cell types important in the pathophysiology of human asthma, adenosine affects bronchial reactivity, inflammation and airway remodelling. Four AR subtypes (A(1), A(2a), A(2b) and A(3)) have been cloned in humans, are expressed in the lung, and are all targets for drug development for human asthma. This review summarizes what is known about these AR subtypes and their function in human asthma as well as the pros and cons of therapeutic approaches to these AR targets. A number of molecules with high affinity and high selectivity for the human AR subtypes have entered clinical trials or are poised to enter clinical trials as anti-asthma treatments. With the availability of these molecules for testing in humans, the function of ARs in human asthma, as well as the safety and efficacy of approaches to the different AR targets, can now be determined.
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Affiliation(s)
- C N Wilson
- Endacea, Inc., Research Triangle Park, NC 27709-2076, USA.
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Xiao LX, Li K, Meng L, Shi DQ. A convenient synthesis of novel 7-phosphonylbenzyl-2-substituted pyrazolo[4,3-e]-1,2,4-triazolo[1,5-c]-pyrimidine derivatives. HETEROATOM CHEMISTRY 2008. [DOI: 10.1002/hc.20478] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/07/2022]
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18
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Doherty AM. Patent Update Cardiovascular & Renal: Treatments for myocardial ischaemia. Expert Opin Ther Pat 2008. [DOI: 10.1517/13543776.4.5.531] [Citation(s) in RCA: 2] [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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19
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Bhagwat SS, Williams M. Patent Update Cardiovascular & Renal: Recent progress in modulators of purinergic activity. Expert Opin Ther Pat 2008. [DOI: 10.1517/13543776.5.6.547] [Citation(s) in RCA: 2] [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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20
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Palmer TM, Stiles GL. The new biology of adenosine receptors. ADVANCES IN ENZYMOLOGY AND RELATED AREAS OF MOLECULAR BIOLOGY 2006; 69:83-120. [PMID: 7817871 DOI: 10.1002/9780470123157.ch3] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/27/2023]
Affiliation(s)
- T M Palmer
- Department of Medicine, Duke University Medical Center, Durham, NC
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21
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Siddiqi SM, Ji XD, Melman N, Olah ME, Jain R, Evans P, Glashofer M, Padgett WL, Cohen LA, Daly JW, Stiles GL, Jacobson KA. A SURVEY OF NONXANTHINE DERIVATIVES AS ADENOSINE RECEPTOR LIGANDS. ACTA ACUST UNITED AC 2006; 15:693-717. [PMID: 27043138 DOI: 10.1080/07328319608002416] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/23/2022]
Abstract
The binding affinities at rat A1, A2a, and A3 adenosine receptors of a wide range of heterocyclic derivatives have been determined. Mono-, bi-, tricyclic and macrocyclic compounds were screened in binding assays, using either [3H]PIA or [3H]CGS 21680 in rat brain membranes or [125I]AB-MECA in CHO cells stably transfected with rat A3 receptors. Several new classes of adenosine antagonists (e.g. 5-oxoimidazopyrimidines and a pyrazoloquinazoline) were identified. Various sulfonylpiperazines, 11-hydroxytetrahydrocarbazolenine, 4H-pyrido[1,2-a]pyrimidinone, folic acid, and cytochalasin H and J bound to A3 receptors selectively. Moreover, cytochalasin A, which bound to A1 adenosine receptors with Ki value of 1.9 μM, inhibited adenylyl cyclase in rat adipocytes, but not via reversible A1 receptor binding.
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Affiliation(s)
- Suhaib M Siddiqi
- Molecular Recognition Section, Laboratory of Bioorganic Chemistry, National Institute of Diabetes, and Digestive and Kidney Diseases, National Institutes of Health, Bethesda, MD 20892
| | - Xiao-Duo Ji
- Molecular Recognition Section, Laboratory of Bioorganic Chemistry, National Institute of Diabetes, and Digestive and Kidney Diseases, National Institutes of Health, Bethesda, MD 20892
| | - Neli Melman
- Molecular Recognition Section, Laboratory of Bioorganic Chemistry, National Institute of Diabetes, and Digestive and Kidney Diseases, National Institutes of Health, Bethesda, MD 20892
| | - Mark E Olah
- Departments of Medicine and Pharmacology, Duke University Medical Center, Durham, NC 27710
| | - Rahul Jain
- Biochemical Mechanisms Section, Laboratory of Bioorganic Chemistry, National Institute of Diabetes, and Digestive and Kidney Diseases, National Institutes of Health, Bethesda, MD 20892
| | - Patricia Evans
- Molecular Recognition Section, Laboratory of Bioorganic Chemistry, National Institute of Diabetes, and Digestive and Kidney Diseases, National Institutes of Health, Bethesda, MD 20892
| | - Marc Glashofer
- Molecular Recognition Section, Laboratory of Bioorganic Chemistry, National Institute of Diabetes, and Digestive and Kidney Diseases, National Institutes of Health, Bethesda, MD 20892
| | - William L Padgett
- Pharmacodynamics Section, Laboratory of Bioorganic Chemistry, National Institute of Diabetes, and Digestive and Kidney Diseases, National Institutes of Health, Bethesda, MD 20892
| | - Louis A Cohen
- Biochemical Mechanisms Section, Laboratory of Bioorganic Chemistry, National Institute of Diabetes, and Digestive and Kidney Diseases, National Institutes of Health, Bethesda, MD 20892
| | - John W Daly
- Pharmacodynamics Section, Laboratory of Bioorganic Chemistry, National Institute of Diabetes, and Digestive and Kidney Diseases, National Institutes of Health, Bethesda, MD 20892
| | - Gary L Stiles
- Departments of Medicine and Pharmacology, Duke University Medical Center, Durham, NC 27710
| | - Kenneth A Jacobson
- Molecular Recognition Section, Laboratory of Bioorganic Chemistry, National Institute of Diabetes, and Digestive and Kidney Diseases, National Institutes of Health, Bethesda, MD 20892
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Abstract
Tecadenoson is a novel selective A1 adenosine receptor agonist that is currently being evaluated for the conversion of paroxysmal supraventricular tachycardia (PSVT) to sinus rhythm. By selectively targeting the A1 receptor, tecadenoson may be associated with fewer adverse effects such as flushing, dyspnea, chest discomfort, and hypotension than adenosine, which is a nonselective agonist of all 4 adenosine receptors. Based on the results of phase I and phase II clinical trials, tecadenoson appears to be an effective agent for producing rapid and sustained conversion of PSVT to sinus rhythm. Additionally, the adverse effects that are typically attributed to adenosine's nonselective stimulation of the A2A, A2B, and A3 receptors appear to occur less frequently with the use of tecadenoson. Tecadenoson also appears to be associated with a lower incidence of atrial fibrillation following conversion of PSVT compared with the rates that have been associated with adenosine in the literature. A randomized, prospective trial will need to be conducted in the future to appropriately compare the safety and efficacy of tecadenoson and adenosine.
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Affiliation(s)
- Carla Peterman
- Department of Pharmacy Services, University of Maryland Medical Center, Baltimore, MD, USA.
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Clark KL, Merkel L. Potential of adenosine receptor agonists for the prevention and treatment of coronary artery disease and acute myocardial infarction. ACTA ACUST UNITED AC 2005. [DOI: 10.1517/14728214.5.1.89] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/05/2022]
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Abstract
Adenosine is an endogenous nucleoside that has potent antiarrhythmic effects on paroxysmal supraventricular tachycardia (PSVT) due to its negative dromotropic effects on the atrioventricular node. In addition to its electrophysiologic effects, adenosine has important effects on vascular smooth muscle cells, inflammatory cells, the central nervous system, and the kidney. Four known adenosine receptor subtypes (A1, A2A, A2B, and A3) mediate the pleiotropic effects of adenosine in humans. These receptors are coupled to a wide range of second messenger cascades. Activation of the A1 adenosine receptor accounts for the negative chronotropic and dromotropic effects of adenosine, whereas A2A, A2B and A3 adenosine receptor activation are responsible for such effects as coronary vasodilation, bronchospasm, inhibition of platelet aggregation, and neuronal stimulation. Elucidation of the specific properties of each of the adenosine receptor subtypes has led to the development of selective ligands as potential therapeutic agents. CVT-510, N-(3(R)-tetrahydrofuranyl)-6-aminopurine riboside, was developed as a selective A1 adenosine receptor agonist that specifically targets the atrioventricular node for termination of PSVT. Preliminary clinical trials have shown that CVT-510 is effective in terminating PSVT and eliminating many of the undesirable adverse effects of adenosine. CVT-510 is also being explored as a potential agent for controlling the ventricular rate of atrial fibrillation and flutter.
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Affiliation(s)
- Jim W Cheung
- Division of Cardiology, Cornell University Medical Center-New York Presbyterian Hospital, New York, NY 10021, USA
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25
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Fahim M, Mustafa SJ. Evidence for the presence of A(1) adenosine receptors in the aorta of spontaneously hypertensive rats. Br J Pharmacol 2001; 134:1760-6. [PMID: 11739253 PMCID: PMC1572910 DOI: 10.1038/sj.bjp.0704433] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022] Open
Abstract
1. Isolated aortic rings (endothelium-intact and -denuded) from spontaneously hypertensive (SHR) and Wistar-Kyoto (WKY) rats were used in this study to examine the vasoactive effects of various adenosine analogues. 2. In phenylephrine contracted aortic rings, concentration-response curves were constructed by cumulative additions (10(-11) - 10(-5) M) of (2S)-N(6)-[2-endo-Norbornyl] adenosine (ENBA), N(6)-cyclopentyladenosine (CPA), R-N(6)-(2-phenylisopropyl) adenosine (R-PIA), 2-p-(-2-carboxyethyl) phenethylamino-5'-N-thylcarboxamido adenosine (CGS-21680). 3. A non-specific adenosine receptor agonist 2-chloroadenosine (CAD) resulted in biphasic response with a small contraction at lower concentrations (10(-9) - 10(-8) M) followed by a significant relaxation at higher concentration in endothelium-intact SHR tissues, suggesting presence of both A(1) and A(2) adenosine receptors in SHR aorta. However, only relaxation was observed in WKY. 4. Contractile response in SHR had the following rank order of potency: ENBA>CPA>R-PIA>CAD. The relaxation response in SHR and WKY had the following rank order of potency: CGS 21680>CAD>R-PIA>CPA>ENBA. 5. Removal of endothelium abolished the adenosine analogue induced contractions in SHR aorta and attenuated the vasorelaxation responses in the WKY and SHR. 6. The contractile response in SHR was abolished by A(1) adenosine receptor antagonist N(6)-endonorbornan-2-yl-9-methyladenine (N-0861). A(2) adenosine receptor antagonist, 3,7-dimethyl-1-proparglyxanthine (DMPX) did not affect the contraction response of adenosine analogues. 7. Endothelium-dependent contractions elicited by A(1) receptor agonists were blocked by indomethacin and by free radical scavengers. 8. These data suggest that the contractile response to adenosine analogues in SHR aorta is probably mediated by free radicals which are generated through the increased cyclo-oxygenase activity occurring in the vascular endothelium of SHR but not the WKY rats.
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Affiliation(s)
- M Fahim
- Department of Pharmacology, School of Medicine, East Carolina University, Greenville, North Carolina, NC 27858, USA.
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26
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Guieu R, Brunet P, Sampol J, Bechis G, Fenouillet E, Mege JL, Capo C, Vitte J, Ibrahim Z, Carrega L, Lerda D, Rochat H, Berland Y, Dussol B. Adenosine and hemodialysis in humans. J Investig Med 2001; 49:56-67. [PMID: 11217148 DOI: 10.2310/6650.2001.34091] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022]
Abstract
BACKGROUND Infections and hypotension are serious complications that develop during hemodialysis (HD) treatment. Adenosine (ADO), a strong hypotensive and immunosuppressive agent, may participate in these two HD complications, because high concentrations of ADO metabolites are found in dialyzed human plasma. ADO, which is released by endothelial cells, is quickly transformed into inosine (INO) by plasmatic ADO deaminase (ADA) and mononuclear cell ADO deaminase (MCADA). In plasma, the degradation of ADO into INO and its uptake by red blood cells (RBC) are both very rapid, resulting in the short half-life of ADO in blood. METHODS Using liquid chromatography, we evaluated ADO and INO plasma concentrations before and after HD session. RESULTS Before the HD session, ADO and INO plasma concentrations were higher in hemodialyzed patients than in controls and in peritoneally dialyzed patients. At the end of the HD session, ADO plasma concentration was increased. ADO plasma concentration for the undialyzed patients was in the same range as that of the controls. Before HD, ADA activity was higher in hemodialyzed patients (559 +/- 349 IU) than in controls (219 +/- 48 IU), and the activity rose during the session (665 +/- 135 IU). ADA activity in the undialyzed patients (222 +/- 80 IU) was in the same range as that of the controls (219 +/- 48 IU). Before the HD session, the MCADA activity (247 +/- 144 IU) was lower than in controls (624 +/- 99 IU). HD did not modify ADO RBC uptake. ADO inhibited mononuclear cell proliferation and interferon-gamma production in humans. Finally, as much as 50 microM INO does not inhibit ADO uptake by RBC and does not modify ADA and MCADA activities. CONCLUSIONS These data indicate that chronic HD inhibited MCADA activity and increased ADO plasma concentration. Both high ADO plasma concentration and low MCADA activity may be involved in dialysis-induced immune system failure and thereby favor infectious diseases.
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Affiliation(s)
- R Guieu
- UMR CNRS 6560, Faculté de Médecine, Secteur Nord, Bd P. Dramard, 13015 Marseille, France.
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Chen CW, Chang HY, Hsiue TR. Mechanism of adenosine-induced vasodilation in rat diaphragm microcirculation. Am J Physiol Heart Circ Physiol 2000; 279:H2210-7. [PMID: 11045955 DOI: 10.1152/ajpheart.2000.279.5.h2210] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
The mechanism of adenosine-induced vasodilation in rat diaphragm microcirculation was investigated using laser Doppler flowmetry. Adenosine (10(-5), 3.2 x 10(-5), and 10(-4) M), the nonselective adenosine agonist 5'-N-ethylcarboxamido-adenosine (NECA) (10(-8)-10(-7) M), the specific A(2A) agonist 2-p-(2-carboxyethyl)phenyl-amino-5'-N-ethyl carboxamidoadenosine (CGS-21680) (10(-8)-10(-7) M), and the adenosine agonist with higher A(1)-receptor affinity, R-N(6)-phenylisopropyladenosine (R-PIA) (10(-7), 3.2 x 10(-7), and 10(-6) M) elicited a similar degree of incremental increase of microcirculatory flow in a dose-dependent manner. The ATP-dependent potassium (K(ATP)) channel blocker glibenclamide (3.2 x 10(-6) M) significantly attenuated the vasodilation effects of these agonists. Adenosine-induced vasodilation could be significantly attenuated by the nonselective adenosine antagonist 8-(p-sulfophenyl)-theophylline (3 x 10(-5) M) or the selective A(2A) antagonist 4-(2-[7-amino-2-(2-furyl)[1,2, 4]triazolo[2,3-a][1,3,5]triazin-5-ylamino]ethyl) phenol (ZM-241385, 10(-6) M), but not by the selective A(1) antagonist 8-cyclopentyl-1, 3-dipropylxanthine (5 x 10(-8) M). Adenylate cyclase inhibitor N-(cis-2-phenyl-cyclopentyl) azacyclotridecan-2-imine-hydrochloride (MDL-12330A, 10(-5)M) effectively suppressed the vasodilator response of adenosine and forskolin. These results suggest that adenosine-induced vasodilation in rat diaphragm microcirculation is mediated through the stimulation of A(2A) receptors, which are coupled to adenylate cyclase activation and opening of the K(ATP) channel.
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Affiliation(s)
- C W Chen
- Department of Internal Medicine, College of Medicine, National Cheng Kung University, Tainan 704, Taiwan, Republic of China
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28
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Fang X, Gaudette D, Furui T, Mao M, Estrella V, Eder A, Pustilnik T, Sasagawa T, Lapushin R, Yu S, Jaffe RB, Wiener JR, Erickson JR, Mills GB. Lysophospholipid growth factors in the initiation, progression, metastases, and management of ovarian cancer. Ann N Y Acad Sci 2000; 905:188-208. [PMID: 10818454 DOI: 10.1111/j.1749-6632.2000.tb06550.x] [Citation(s) in RCA: 195] [Impact Index Per Article: 8.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/26/2022]
Abstract
Levels of lysophosphatidic acid (LPA) and lysophosphatidylcholine (LPC) are elevated in the plasma and ascites of ovarian cancer patients, but not in most other tumor types. LPA increases cell proliferation, cell survival, resistance to cisplatin, cell shrinkage, and production of vascular endothelial growth factor, urokinase plasminogen activator, and LPA itself in ovarian cancer cells, but not in normal ovarian surface epithelial cells. PSP24 and members of the endothelial differentiation gene (EDG) family (EDG1, EDG2, EDG4, and EDG7) of G protein-coupled receptors mediate LPA signaling. Ovarian cancer cell lines do not express EDG1 mRNA, have variable EDG2 mRNA and protein levels, and frequently exhibit levels of EDG4 mRNA and protein, suggesting that EDG4 may contribute to the deleterious effects of LPA in ovarian cancer. In contrast, activation of the EDG2 LPA receptor on ovarian cancer cells may lead to apoptosis and counter the effects of other LPA receptors. Thus, the development of agonists and antagonists for the appropriate spectrum of LPA receptors may alter proliferation, apoptosis, or response to therapy of ovarian cancer cells. Indeed, over 60% of all current drugs target the G protein-coupled family of receptors, making the LPA receptor family a "drugable" target. LPC, although not as thoroughly studied, increases cellular proliferation and mediates multiple other functions through unique signaling pathways.
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Affiliation(s)
- X Fang
- Department of Molecular Oncology, University of Texas, MD Anderson Cancer Center, Houston 77030, USA.
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Moreau JL, Huber G. Central adenosine A(2A) receptors: an overview. BRAIN RESEARCH. BRAIN RESEARCH REVIEWS 1999; 31:65-82. [PMID: 10611496 DOI: 10.1016/s0165-0173(99)00059-4] [Citation(s) in RCA: 109] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
Recent advances in molecular biology, biochemistry, cell biology and behavioral pharmacology together with the development of more selective ligands to the various adenosine receptors have increased our understanding of the functioning of central adenosine A(2A) receptors. The A(2A) receptor is one of four adenosine receptors found in the brain. Its expression is highest in striatum, nucleus accumbens and olfactory tubercles, although it also occurs in neurons and microglia in most other brain regions. The receptor has seven transmembrane domains and couples via Gs to adenyl cyclase stimulation. Antagonistic interactions between A(2A) receptors and dopamine D(2) receptors have been described, as stimulation of the A(2A) receptor leads to a reduction in the affinity of D(2) receptors for D(2) receptor agonists. The A(2A) receptor is thought to play a role in a number of physiological responses and pathological conditions. Indeed, A(2A) receptor antagonists may be useful for the treatment of acute and chronic neurodegenerative disorders such as cerebral ischemia or Parkinson's disease. A(2A) receptor agonists may treat certain types of seizures or sleep disorders. This review discusses the characteristics, distribution, pharmacochemical properties and regulation of central A(2A) receptors, as well as A(2A) receptor-mediated behavioural responses and their potential role in various neuropsychiatric disorders.
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Affiliation(s)
- J L Moreau
- Pharma Division, Preclinical CNS Research, F. Hoffmann-La Roche, PRPN, 72/141, CH-4070, Basel, Switzerland.
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30
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van Baal J, Hoenderop JG, Groenendijk M, van Os CH, Bindels RJ, Willems PH. Hormone-stimulated Ca2+ transport in rabbit kidney: multiple sites of inhibition by exogenous ATP. THE AMERICAN JOURNAL OF PHYSIOLOGY 1999; 277:F899-906. [PMID: 10600937 DOI: 10.1152/ajprenal.1999.277.6.f899] [Citation(s) in RCA: 13] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
Exogenous ATP markedly reduced 1-desamino-8-D-arginine vasopressin (dDAVP)-stimulated Ca2+ transport and cAMP accumulation in primary cultures of rabbit connecting tubule and cortical collecting duct cells. Similarly, ATP inhibited the stimulatory effect of 8-bromo-cAMP. At first sight, this is in agreement with the "classic" concept that dDAVP exerts its stimulatory effect via cAMP. However, dDAVP-stimulated Ca2+ transport was markedly reduced by the protein kinase C (PKC) inhibitor chelerythrine, reported previously to inhibit the cAMP-independent pathway responsible for parathyroid hormone-, [Arg8]vasopressin-, PGE2-, and adenosine-stimulated Ca2+ transport. Chelerythrine also inhibited the increase in Ca2+ transport evoked by the cAMP-independent A1 receptor agonist N6-cyclopentyladenosine (CPA). Downregulation of phorbol ester-sensitive PKC isoforms by chronic phorbol ester treatment has been shown before to be without effect on hormone-stimulated Ca2+ transport, indicating that the chelerythrine-inhibitable pathway consists of a phorbol ester-insensitive PKC isoform. Here, this maneuver did not affect ATP inhibition of dDAVP-stimulated Ca2+ transport and cAMP formation, while abolishing ATP inhibition of CPA-stimulated Ca2+ transport. These findings show that ATP acts via 1) a phorbol ester-sensitive PKC isoform to inhibit hormonal stimulation of Ca2+ transport at the level of the chelerythrine-inhibitable pathway involving a phorbol ester-insensitive PKC isoform and 2) a phorbol ester-insensitive mechanism to inhibit V2 receptor-mediated concomitant activation of this pathway and adenylyl cyclase.
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Affiliation(s)
- J van Baal
- Department of Cell Physiology, University of Nijmegen, 6500 HB Nijmegen, The Netherlands
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31
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Tatsis-Kotsidis I, Erlanger BF. A1 adenosine receptor of human and mouse adipose tissues: cloning, expression, and characterization. Biochem Pharmacol 1999; 58:1269-77. [PMID: 10487528 DOI: 10.1016/s0006-2952(99)00214-2] [Citation(s) in RCA: 16] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/16/2022]
Abstract
The aberrant functioning of the A1 adenosine receptor of adipose tissue has been implicated as a factor in obesity. To begin to address questions concerning this relationship, the possibility of a unique A1 adenosine receptor in adipose tissue must be investigated. Therefore, cDNAs encoding the A1 adenosine receptors of adipose tissues of a mouse and an obese human were isolated, sequenced, and expressed in eukaryotic cells. We found their sequences to be 90% identical and each identical to published sequences of the receptors in brain preparations of the two species. The two cDNAs were transiently expressed in 293T cells, a human kidney cell line. Despite the 90% identity in their sequences, the ligand binding properties of the human and mouse cDNAs expressed in the 293T cell line differed markedly. With respect to amino acid differences in the extracellular loops, four occur in the second extracellular loop, which has been implicated in binding by other studies. The ligand binding characteristics of the recombinant receptors matched those of native receptors from human and mouse adipose tissue. The human A1 receptor cDNA was also expressed in ob17 preadipocyte cells to investigate reported influences of cellular environment on binding characteristics. We compared ligand binding of the expressed receptor in the two cell lines (ob17 and 293T). We also compared ligand binding of native receptors from mouse brain and adipose tissue preparations. In both studies, cellular environment had no affect on binding characteristics. This conclusive evidence resolves earlier conflicting reports in the literature.
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Affiliation(s)
- I Tatsis-Kotsidis
- Institute of Human Nutrition and Department of Microbiology, Columbia University, New York, NY 10032, USA
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32
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Dalpiaz A, Scatturin A, Pavan B, Varani K, IJzerman AP, Andrea Borea P. Thermodynamic in vitro studies as a method to investigate the pharmacodynamic behavior of adenosine A1 receptor ligands. Pharm Res 1999; 16:1054-8. [PMID: 10450930 DOI: 10.1023/a:1018987816891] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022]
Abstract
PURPOSE A thermodynamic analysis of the binding to rat cortex adenosine A1 receptor of N6-substituted (full agonists) and N6-substituted-deoxyribose (partial agonists) adenosine derivatives was performed. The intrinsic activity of the compounds was evaluated by measurements of the inhibition of forskolin stimulated 3', 5'-cyclic adenosine monophosphate (c-AMP) levels in isolated epididymal rat adipocytes. METHODS The thermodynamic parameters deltaG(o) (standard free energy), deltaH(o) (standard enthalpy), and deltaS(o) (standard entropy) of the binding equilibrium were determined by means of affinity measurements carried out at different temperatures (0, 10, 20, 25, 30 degrees C). Levels of c-AMP were evaluated performing competitive protein binding assays. RESULTS The binding of the ligands increases with temperature enhancement and, as a consequence, is totally entropy driven. Standard entropy values correlate significantly with intrinsic activity ones. CONCLUSIONS It is proposed the data obtained by these in vitro experiments can be used to investigate the in vivo pharmacodynamic of A, full and partial agonists.
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Affiliation(s)
- A Dalpiaz
- Department of Pharmaceutical Sciences, Ferrara, Italy
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33
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Baraldi PG, Borea PA, Bergonzoni M, Cacciari B, Ongini E, Recanatini M, Spalluto G. Comparative molecular field analysis (CoMFA) of a series of selective adenosine receptor A2A antagonists. Drug Dev Res 1999. [DOI: 10.1002/(sici)1098-2299(199902)46:2<126::aid-ddr5>3.0.co;2-7] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/02/2023]
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Abstract
A stability study of adenosine receptor agonists in rat and human whole blood was performed. The compounds were incubated at 37 degrees in fresh blood, and aliquots of the incubation mixture were hemolyzed at regular time intervals and analyzed with HPLC. N6-cyclopentyladenosine (CPA) and N6-cyclobutyladenosine (CBA) were degraded, whereas N6-cyclohexyladenosine, N6-cycloheptyladenosine and N6-sulfophenyladenosine were not. 2-Chloroadenosine had a half-life very similar to that of CPA. However, the 2'-, 3'-, and 5'-deoxyribose derivatives of CPA remained intact. The nucleoside transport inhibitor nitrobenzylthioinosine attenuated CBA and CPA metabolism in rat blood as did the inhibitor of adenosine deaminase erythro-9-(2-hydroxy-3-nonyl)adenine, albeit at relatively high concentrations. Complete blockade of CBA and CPA degradation was achieved by a preincubation of rat and human blood with the adenosine kinase (AK) inhibitor 5'-amino-5'-deoxyadenosine. We conclude that the two adenosine analogues are metabolized by AK both in rat and in human whole blood.
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Affiliation(s)
- B Pavan
- Division of Medicinal Chemistry, Leiden/Amsterdam Center for Drug Research, Leiden University, The Netherlands
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35
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Ceccarelli S, D'Alessandro A, Prinzivalli M, Zanarella S. Imidazo[1,2-a]quinoxalin-4-amines: A novel class of nonxanthine A1-adenosine receptor antagonists. Eur J Med Chem 1998. [DOI: 10.1016/s0223-5234(99)80019-1] [Citation(s) in RCA: 17] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/17/2022]
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36
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Dalpiaz A, Townsend-Nicholson A, Beukers MW, Schofield PR, IJzerman AP. Thermodynamics of full agonist, partial agonist, and antagonist binding to wild-type and mutant adenosine A1 receptors. Biochem Pharmacol 1998; 56:1437-45. [PMID: 9827575 DOI: 10.1016/s0006-2952(98)00202-0] [Citation(s) in RCA: 41] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/15/2022]
Abstract
A thermodynamic analysis of the binding of a full agonist (N6-cyclopentyladenosine), a partial agonist (8-butylamino-N6-cyclopentyladenosine) and an antagonist (8-cyclopentyltheophylline) to human wild-type and mutant (mutation of a threonine (Thr) to an alanine (Ala) residue at position 277) adenosine A1 receptors expressed on Chinese hamster ovary (CHO) cells, and to rat brain adenosine A1 receptors was undertaken. The thermodynamic parameters deltaGo (standard free energy), deltaHo (standard enthalpy) and deltaSo (standard entropy) of the binding equilibrium to rat brain receptors were determined by means of affinity measurements carried out at four different temperatures (0, 10, 20 and 25 degrees) and van't Hoff plots. Two temperatures (0 and 25 degrees) were considered for human receptors. Affinity constants were obtained from inhibition assays on membrane preparations of rat brain and CHO cells by use of the antagonist [3H]1,3-dipropyl-8-cyclopentylxanthine ([3H]DPCPX) as selective adenosine A1 receptor radioligand. As for rat brain receptors, full agonist binding was totally entropy driven, whereas antagonist binding was essentially enthalpy driven. Partial agonist binding appeared both enthalpy and entropy driven. As for human receptors, full agonist affinity was highly dependent on the presence of Thr277. Moreover, affinity to both wild-type and mutant receptors was enhanced by temperature increase, suggesting a totally entropy-driven binding. Antagonist binding did not depend on the presence of Thr277. Antagonist affinity decreased with an increase in temperature, suggesting a mainly enthalpy-driven binding. Partial agonist binding was significantly dependent on the presence of Thr277 at 25 degrees, whereas such a dependence was not evident at 0 degrees. It is concluded that Thr277 contributes only to the binding of adenosine derivatives and that its role changes drastically with the receptor conformation and with the type of agonist (full or partial) interacting with the adenosine A1 receptors.
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Affiliation(s)
- A Dalpiaz
- Leiden/Amsterdam Center for Drug Research, Division of Medicinal Chemistry, Leiden, The Netherlands
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37
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Guieu R, Dussol B, Halimi G, Bechis G, Sampieri F, Berland Y, Sampol J, Couraud F, Rochat H. Adenosine and the nervous system: pharmacological data and therapeutic perspectives. GENERAL PHARMACOLOGY 1998; 31:553-61. [PMID: 9792214 DOI: 10.1016/s0306-3623(98)00071-8] [Citation(s) in RCA: 24] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/25/2022]
Abstract
1. Adenosine acts on a family of G-protein-coupled receptors called purinoreceptors. 2. Four subtypes have been cloned and pharmacologically characterized. 3. The principal pharmacological data and structure-function relations for agonist interactions with P1 receptors are presented. 4. We conclude that the potent role of adenosine in the nervous system may be interesting for the development of drugs targeted at purines and their receptors.
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Affiliation(s)
- R Guieu
- Laboratoire de Biochimie et d'Ingéniérie des Protéines, URA CNRS 1455 Faculté de Médecine Secteur Nord, Marseille, France
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Stillman BA, Audoly L, Breyer RM. A conserved threonine in the second extracellular loop of the human EP2 and EP4 receptors is required for ligand binding. Eur J Pharmacol 1998; 357:73-82. [PMID: 9788776 DOI: 10.1016/s0014-2999(98)00522-6] [Citation(s) in RCA: 38] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/19/2022]
Abstract
G protein coupled receptors for prostaglandins are activated when agonists are bound to a binding pocket formed in part by the seven transmembrane domains. Recent studies have determined that substitution of a conserved threonine in the second extracellular loop of the prostaglandin EP3 receptor resulted in increased affinity for ligands with a C1 methyl ester moiety. The homologous threonine in the second extracellular loop of the human prostaglandin EP2 and EP4 receptors was mutated to alanine. When expressed in COS1 cells, detectable radioligand binding at both of these receptors bearing the threonine to alanine substitution (EP2T185A; EP4T168A) was abolished, as well as the receptors' ability to stimulate intracellular [cAMP]. In contrast, EP2 and EP4 receptors bearing conservative threonine to serine mutations (EP2T185S; EP4T168S) displayed Kd values for [3H]prostaglandin E2 similar to wild type receptors: 8.8 +/- 0.7 nM for EP2T185S compared to 12.9 +/- 1.2 nM for EP2 wild type; 2.0 +/- 0.8 nM for EP4T168S compared to 0.9 +/- 0.3 nM for the EP4 wild type receptor. The EC50 values for cAMP stimulation were 1.3 +/- 0.6 nM for EP2 wild type; 2.7 +/- 1.3 nM for EP2T185S; 1.1 +/- 0.3 nM for EP4 wild type; and 1.4 +/- 0.33 nM for EP4T168S. These studies suggest a critical role for the hydroxyl moiety on these conserved threonine residues at position 168/185 of the second extracellular loop in prostaglandin receptor-ligand interactions.
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Affiliation(s)
- B A Stillman
- Department of Pharmacology and Vanderbilt Cancer Center, Vanderbilt University School of Medicine, Nashville, TN 37232-2372, USA
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Hata K, Whittaker P, Kloner RA, Przyklenk K. Brief antecedent ischemia attenuates platelet-mediated thrombosis in damaged and stenotic canine coronary arteries: role of adenosine. Circulation 1998; 97:692-702. [PMID: 9495306 DOI: 10.1161/01.cir.97.7.692] [Citation(s) in RCA: 47] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 02/06/2023]
Abstract
BACKGROUND Recent studies suggest that patients with angina before myocardial infarction exhibit improved recovery of coronary perfusion after thrombolysis by an as-yet-unknown mechanism. We therefore proposed that brief antecedent ischemia/reperfusion may, via release of adenosine, improve vessel patency in damaged and stenotic coronary arteries. METHODS AND RESULTS Anesthetized dogs underwent coronary injury + stenosis, resulting in repeated cyclic variations in coronary blood flow (CFVs) caused by the formation/dislodgment of platelet-rich thrombi. Vessel patency was assessed for 3 hours after stenosis by quantification of the nadir of the CFVs, duration of total thrombotic occlusion (flow=0), and area of the flow-time profile (expressed as percent of baseline flow x 180 minutes). In protocol 1, dogs received 10 minutes of coronary occlusion + 10 minutes of reflow or a comparable 20-minute control period before injury + stenosis. The median nadir of the CFVs was higher (4.0 versus 0.3 mL/min), median zero flow duration per 30-minute time interval was shorter (0.4 versus 15.1 minutes), and mean percent flow-time area was greater (54+/-8% versus 28+/-9%) in dogs that received antecedent ischemia versus controls (P<.05). These benefits of antecedent ischemia/reperfusion were largely mimicked by a 10-minute intracoronary adenosine infusion (400 microg/min) in lieu of brief ischemia (protocol 2) and were abolished by administration of the adenosine A1/A2 receptor antagonist PD 115,199 (3 mg/kg i.v.) before brief antecedent coronary occlusion (protocol 3). CONCLUSIONS Brief antecedent ischemia attenuates subsequent platelet-mediated thrombosis in damaged and stenotic canine coronary arteries, due, in large part, to an adenosine-mediated mechanism.
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Affiliation(s)
- K Hata
- Heart Institute, Good Samaritan Hospital and Department of Medicine, University of Southern California, Los Angeles 90017-2395, USA
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Daval JL, Nicolas F. Non-selective effects of adenosine A1 receptor ligands on energy metabolism and macromolecular biosynthesis in cultured central neurons. Biochem Pharmacol 1998; 55:141-9. [PMID: 9448736 DOI: 10.1016/s0006-2952(97)00378-x] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/05/2023]
Abstract
To investigate the effects of adenosine A1 receptor activation on energy metabolism and RNA and protein biosynthesis in central neurons, cultured neurons from the rat forebrain were exposed for 1 hr to 72 hr to various concentrations (10 nM-100 microM) of the selective A1 receptor agonist 2-chloro-N6-cyclopentyladenosine (CCPA) or the A1 receptor antagonist 8-cyclopentyltheophylline (CPT). At all concentrations tested, the adenosinergic compounds did not affect cell viability within 72 hr of treatment, except for CPT, which reduced viability by 19.7% when used at the concentration of 100 microM. Energy metabolism was analysed by studying the specific uptake of 2-D-[3H]deoxyglucose ([3H]2DG). Rates of RNA and protein biosynthesis were assessed by the measurement of [3H]uridine and [3H]leucine incorporation, respectively. Neuronal [3H]2DG uptake was increased by 16% (P < 0.01) after 8 hr in the presence of 100 microM CCPA, whereas 100 microM CPT for 24 hr also increased [3H]2DG uptake (8%, P < 0.01). At these concentrations, both ligands inhibited [3H]uridine incorporation after a 3-hr treatment by 92% and 30%, respectively. CCPA never altered [3H]leucine incorporation when compared to controls, and CPT significantly inhibited protein synthesis only at 10-100 microM. Additional experiments to analyse the influence of A1 ligands on the transport of [3H]2DG, [3H]leucine and [3H]uridine suggested that CCPA and CPT, which interact functionally with adenosine receptors by regulating cyclic AMP production in this model, are able to alter energy metabolism and RNA synthesis in central neurons in a nonspecific manner by interacting with glucose and uridine transporters.
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Affiliation(s)
- J L Daval
- INSERM U.272, Université Henri Poincaré, Nancy, France.
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Adenosine. ANNUAL REPORTS IN MEDICINAL CHEMISTRY 1998. [DOI: 10.1016/s0065-7743(08)61076-3] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register]
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Bischofberger N, Jacobson KA, von Lubitz DK. Adenosine A1 receptor agonists as clinically viable agents for treatment of ischemic brain disorders. Ann N Y Acad Sci 1997; 825:23-9. [PMID: 9369972 PMCID: PMC3445622 DOI: 10.1111/j.1749-6632.1997.tb48411.x] [Citation(s) in RCA: 38] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/05/2023]
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Lakhlani PP, MacMillan LB, Guo TZ, McCool BA, Lovinger DM, Maze M, Limbird LE. Substitution of a mutant alpha2a-adrenergic receptor via "hit and run" gene targeting reveals the role of this subtype in sedative, analgesic, and anesthetic-sparing responses in vivo. Proc Natl Acad Sci U S A 1997; 94:9950-5. [PMID: 9275232 PMCID: PMC23306 DOI: 10.1073/pnas.94.18.9950] [Citation(s) in RCA: 258] [Impact Index Per Article: 9.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/03/1997] [Indexed: 02/05/2023] Open
Abstract
Norepinephrine contributes to antinociceptive, sedative, and sympatholytic responses in vivo, and alpha2 adrenergic receptor (alpha2AR) agonists are used clinically to mimic these effects. Lack of subtype-specific agonists has prevented elucidation of the role that each alpha2AR subtype (alpha2A, alpha2B, and alpha2C) plays in these central effects. Here we demonstrate that alpha2AR agonist-elicited sedative, anesthetic-sparing, and analgesic responses are lost in a mouse line expressing a subtly mutated alpha2AAR, D79N alpha2AAR, created by two-step homologous recombination. These functional changes are accompanied by failure of the D79N alpha2AAR to inhibit voltage-gated Ca2+ currents and spontaneous neuronal firing, a measure of K+ current activation. These results provide definitive evidence that the alpha2AAR subtype is the primary mediator of clinically important central actions of alpha2AR agonists and suggest that the D79N alpha2AAR mouse may serve as a model for exploring other possible alpha2AAR functions in vivo.
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Affiliation(s)
- P P Lakhlani
- Department of Pharmacology, Vanderbilt University, Nashville, TN 37232, USA
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Zhang J, Belardinelli L, Jacobson KA, Otero DH, Baker SP. Persistent activation by and receptor reserve for an irreversible A1-adenosine receptor agonist in DDT1 MF-2 cells and in guinea pig heart. Mol Pharmacol 1997; 52:491-8. [PMID: 9281612 PMCID: PMC5472056 DOI: 10.1124/mol.52.3.491] [Citation(s) in RCA: 22] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/05/2023] Open
Abstract
The p- and m-isothiocyanate adenosine derivatives N6-[4-[[[4-[[[[2-[[[(p-(m)-isothiocyanatophenyl)amino]thiocarbonyl ]am ino]ethyl]amino]carbonyl]methyl]anilino]carbonyl]methyl]phenyl] adenosine (p- and m-DITC-ADAC) were examined for irreversible agonist effects at the A1-adenosine receptor (A1-AdoR) in DDT1 MF-2 (DDT) cells and a functional A1-AdoR response in the guinea pig isolated heart. The p- and m-DITC-ADAC inhibited (-)-isoproterenol stimulated cAMP accumulation in DDT cells in the low nanomolar range, and the maximal responses elicited by both compounds were similar to that for N6-cyclopentyladenosine. Once established, the p-DITC-ADAC-mediated inhibition of cAMP accumulation in DDT cells was not affected by the addition of the AdoR antagonist 8-cyclopentyl-1,3-dipropylxanthine (CPX). Pretreatment of DDT cells with p-DITC-ADAC (1 microM), followed by washing, reduced [3H]CPX binding to the A1-AdoR by 44% without altering the Kd value for the radioligand to the remaining receptors. The relationship between irreversible A1-AdoR occupancy by p-DITC-ADAC and inhibition of cAMP accumulation revealed a relatively large receptor reserve (64%) for the maximal response. In guinea pig isolated hearts, m-DITC-ADAC (5 microM) prolonged the stimulus to His bundle (SH) interval by 2.1-fold; this response could be prevented by the antagonist 8-cyclopentyltheophylline (5 microM). However, after the SH interval prolongation was established, extensive washout or the addition of 8-cyclopentyltheophylline had little reversal effect on the m-DITC-ADAC response. Binding of [3H]CPX to the guinea pig ventricular membranes after m-DITC-ADAC treatment and washing was reduced by 35%. The A1-AdoR occupancy response relationship for m-DITC-ADAC to prolong the SH interval indicated a small (10-20%) receptor reserve. Both p -and m-DITC-ADAC seem to be irreversible full agonists at the A1-AdoR and may prove to be useful probes to further investigate A1-AdoR structure-function relationships.
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Affiliation(s)
- J Zhang
- Department of Pharmacology, University of Florida, Gainesville, Florida 32610, USA
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Adenot M, Benezech V, Bompart J, Bonnet P, Chapat J, Grassy G. Interest of cluster significance analysis in structure-affinity relationships for non-xanthine heterocyclic antagonists of adenosine. Eur J Med Chem 1997. [DOI: 10.1016/s0223-5234(97)84012-3] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/18/2022]
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46
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Matova M, Nacheva R, Boicheva S. QSAR analysis of 2-alkyloxy and 2-aralkyloxy adenosine A1- and A2-agonists. Eur J Med Chem 1997. [DOI: 10.1016/s0223-5234(97)84013-5] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/17/2022]
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Martini C, Trincavelli L, Lucacchini A. Chemical modifications of striatal A2A adenosine receptors: a possible role for tyrosine at the ligand binding sites. BIOCHIMICA ET BIOPHYSICA ACTA 1997; 1326:67-74. [PMID: 9188801 DOI: 10.1016/s0005-2736(96)00243-x] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 02/04/2023]
Abstract
A2A adenosine receptors were examined in bovine striatal membranes following exposure to tetranitromethane (TNM) which modifies tyrosine and cysteine residues. TNM (0.05-0.5 mM) treatment caused an irreversible, concentration-dependent decrease in the binding activity of the selective A2A agonist [3H]CGS 21680. Protection studies showed that TNM inactivation could be prevented by the adenosine receptor agonist 5'-N-ethylcarboxamidoadenosine (NECA) and by the antagonist xanthine amine congener (XAC), suggesting that TNM modified residues at the ligand-binding sites. Scatchard analysis of the binding data showed that 0.15 mM TNM decreased the [3H]CGS 21680 Bmax value from 447 +/- 39 to 273 +/- 21 fmol/mg of proteins without any significant change in the Kd values (13.5 +/- 1.4 and 14.7 +/- 1.5 for control and treated membranes, respectively). We carried out a series of successive chemical modifications with the reducing agent dithiothreitol (DTT), which indicated that the residues modified by TNM, under our experimental conditions, are tyrosine residues and not cysteine residues.
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Affiliation(s)
- C Martini
- Istituto Policattedra di Discipline Biologiche, Università di Pisa, Italy.
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Cox MH, O SJ, Hebbar L, Mukherjee R, Crawford FA, Spinale FG. Protective effects of adenosine on myocyte contractility during cardioplegic arrest. Ann Thorac Surg 1997; 63:981-7. [PMID: 9124975 DOI: 10.1016/s0003-4975(96)01252-0] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 02/04/2023]
Abstract
BACKGROUND Adenosine delivery to the left ventricular myocardium has been demonstrated to provide protective effects in the setting of ischemia and reperfusion. However, whether adenosine has direct protective effects on isolated myocytes in the setting of cardioplegic arrest was unclear. METHODS Isolated porcine left ventricular myocytes were assigned to one of the following treatment groups: (1) cardioplegia: 24 mEq/L K+, 4 degrees C for 2 hours followed by rewarming (cell media, 37 degrees C; n = 29); (2) cardioplegia augmented with adenosine (1 to 200 micromol/L) followed by rewarming (n = 98); and (3) normothermic control (cell media, 37 degrees C, 2 hours; n = 175). Myocyte contractility was measured by computer-aided videomicroscopy. RESULTS Cardioplegic arrest and rewarming reduced myocyte shortening velocity compared with normothermic control (25.3 +/- 2.5 microm/s versus 50.9 +/- 1.4 microm/s, p < 0.05). Adenosine-augmented cardioplegic arrest improved myocyte contractility with rewarming in a concentration-dependent fashion. For example, cardioplegia augmented with 10 micromol/L adenosine improved myocyte shortening velocity by 33% (33.6 +/- 3.0 microm/s versus 25.3 +/- 2.5 microm/s, p < 0.05), whereas 200 micromol/L adenosine improved shortening velocity by 97% (49.9 +/- 3.4 microm/s vs 25.3 +/- 2.5 microm/s, p < 0.05) compared with conventional cardioplegia. CONCLUSIONS This study demonstrated concentration-dependent protective effects of adenosine-augmented cardioplegia on myocyte contractile function with subsequent reperfusion and rewarming. These results suggest that stimulation of putative myocyte adenosine receptors may provide enhanced protective effects on myocyte contractile processes during cardioplegic arrest.
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Affiliation(s)
- M H Cox
- Division of Cardiothoracic Surgery, Medical University of South Carolina, Charleston 29425, USA
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Stowe DF, Boban M, Roerig DL, Chang D, Palmisano BW, Bosnjak ZJ. Effects of L-arginine and N omega-nitro-L-arginine methyl ester on cardiac perfusion and function after 1-day cold preservation of isolated hearts. Circulation 1997; 95:1623-34. [PMID: 9118533 DOI: 10.1161/01.cir.95.6.1623] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 02/04/2023]
Abstract
BACKGROUND Coronary flow responses to endothelium-dependent (acetylcholine [ACh] or 5-hydroxytryptamine [5-HT]) and endothelium-independent (adenosine [ADE] or nitroprusside [NP]) vasodilators may be altered before and after 1-day hypothermia during the perfusion of arginine vasopressin (AVP), D-arginine (D-ARG), L-arginine (L-ARG), or nitro-L-arginine methyl ester (L-NAME). METHODS AND RESULTS Four groups of guinea pig hearts (37.5 degrees C [warm]) were perfused for 6 hours with AVP, L-ARG, L-NAME, or nothing (control). Five heart groups (cold) were perfused with AVP, D-ARG, L-ARG, L-NAME, or nothing (control), but after 2 hours they were perfused at low flow for 22 hours at 3.7 degrees C and again for 3 hours at 37.5 degrees C. ADE, butanedione monoxime, and NP were given for cardioprotection before, during, and after hypothermia. In warm groups, L-ARG did not alter basal flow or ADE, ACh, 5-HT, or NP responses, whereas L-NAME and AVP reduced basal flow and the ADE response, abolished ACh and 5-HT responses, and increased the NP response. In cold groups after hypothermia. L-ARG did not alter basal flow, but L-NAME, AVP, D-ARG, and control reduced flow. In the postcold L-ARG group, ACh increased peak flow, but NP did not increase flow in other cold groups. Effluent L-ARG and L-CIT in the cold control group fell from 64 +/- 9 and 9 +/- 1 micrograms/L at 1 hour to 36 +/- 5 and 5 +/- 1 micrograms/L at 25 hours, respectively. Left ventricular pressure and cardiac efficiency improved more in the postcold L-ARG group than in the postcold D-ARG, AVP, and L-NAME groups. CONCLUSIONS Endogenous effluent levels of L-ARG and L-CIT decrease after 24 hours in isolated hearts, whereas perfusion of L-ARG improves cardiac performance, basal coronary flow, and vasodilator responses. In contrast, L-NAME, L-ARG, and AVP limit flow and performance but maintain a partial vasodilatory response to NP. Sustained release of NO may account for improved performance after L-ARG after hypothermia.
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Affiliation(s)
- D F Stowe
- Department of Anesthesiology, Medical College of Wisconsin, Milwaukee 53226, USA
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Mazzoni MR, Giusti L, Rossi E, Taddei S, Lucacchini A. Role of cysteine residues of rat A2a adenosine receptors in agonist binding. BIOCHIMICA ET BIOPHYSICA ACTA 1997; 1324:159-70. [PMID: 9059509 DOI: 10.1016/s0005-2736(96)00223-4] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 02/03/2023]
Abstract
In the present study, we investigated the role of disulfide bridges and sulfhydryl groups in A2a adenosine receptor binding of the agonist 2-p-(2-carboxyethyl)phenylethylamino)-5'-N-ethylcarboxamidoadenosi ne (CGS 21680). To evaluate the presence of essential disulfide bridges, rat striatal membranes were incubated with [3H]CGS 21680 in the presence of dithiothreitol and binding of the agonist to membranes was measured. The amount of [3H]CGS 21680 which specifically bound, decreased progressively upon pretreatment of membranes with increasing concentrations of dithiothreitol. Pretreatment of rat striatal membranes with 12.5 mM dithiothreitol for 15 min at 25 degrees C resulted in a 2-fold decrease of A2a adenosine receptor affinity for [3H]CGS 21680, and a reduction in the maximal number of binding sites. The presence of agonist or antagonist ligands protected the A2a adenosine receptor sites from the effect of dithiothreitol. We also examined the susceptibility of A2a adenosine receptors to inactivation by the sulfhydryl alkylating reagent, N-ethylmaleimide. When rat striatal membranes were pretreated with N-ethylmaleimide for 30 minutes at 37 degrees C, a decrease in specific [3H]CGS 21680 binding was observed. Pretreatment of membranes with 1 mM N-ethylmaleimide also resulted in a 2-fold reduction of A2a adenosine receptor affinity for [3H]CGS 21680, as well as a slight decrease in the maximal number of binding sites. Neither agonist nor antagonist ligands were effective in protecting the receptor sites from inactivation by N-ethylmaleimide. In contrast, addition of 100 microM guanosine-5'-O-(3-thiotriphosphate) or 5'-guanylylimidodiphosphate were both effective in protecting the receptor sites from inactivation by N-ethylmaleimide. This protective effect was significant but not complete. Our data suggest that disulfide bridges play a role in the structural integrity of the A2a adenosine receptor, furthermore, reduced sulfhydryl groups appear to be important but we do not yet know if they are on the receptor or on the Gs alpha subunit.
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Affiliation(s)
- M R Mazzoni
- Istituto Policattedra di Discipline Biologiche, University of Pisa, Italy.
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