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Strickland LN, Faraoni EY, Ruan W, Yuan X, Eltzschig HK, Bailey-Lundberg JM. The resurgence of the Adora2b receptor as an immunotherapeutic target in pancreatic cancer. Front Immunol 2023; 14:1163585. [PMID: 37187740 PMCID: PMC10175829 DOI: 10.3389/fimmu.2023.1163585] [Citation(s) in RCA: 4] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/11/2023] [Accepted: 04/19/2023] [Indexed: 05/17/2023] Open
Abstract
Pancreatic ductal adenocarcinoma (PDAC) is characterized by a dense desmoplastic stroma that impedes drug delivery, reduces parenchymal blood flow, and suppresses the anti-tumor immune response. The extracellular matrix and abundance of stromal cells result in severe hypoxia within the tumor microenvironment (TME), and emerging publications evaluating PDAC tumorigenesis have shown the adenosine signaling pathway promotes an immunosuppressive TME and contributes to the overall low survival rate. Hypoxia increases many elements of the adenosine signaling pathway, resulting in higher adenosine levels in the TME, further contributing to immune suppression. Extracellular adenosine signals through 4 adenosine receptors (Adora1, Adora2a, Adora2b, Adora3). Of the 4 receptors, Adora2b has the lowest affinity for adenosine and thus, has important consequences when stimulated by adenosine binding in the hypoxic TME. We and others have shown that Adora2b is present in normal pancreas tissue, and in injured or diseased pancreatic tissue, Adora2b levels are significantly elevated. The Adora2b receptor is present on many immune cells, including macrophages, dendritic cells, natural killer cells, natural killer T cells, γδ T cells, B cells, T cells, CD4+ T cells, and CD8+ T cells. In these immune cell types, adenosine signaling through Adora2b can reduce the adaptive anti-tumor response, augmenting immune suppression, or may contribute to transformation and changes in fibrosis, perineural invasion, or the vasculature by binding the Adora2b receptor on neoplastic epithelial cells, cancer-associated fibroblasts, blood vessels, lymphatic vessels, and nerves. In this review, we discuss the mechanistic consequences of Adora2b activation on cell types in the tumor microenvironment. As the cell-autonomous role of adenosine signaling through Adora2b has not been comprehensively studied in pancreatic cancer cells, we will also discuss published data from other malignancies to infer emerging therapeutic considerations for targeting the Adora2b adenosine receptor to reduce the proliferative, invasive, and metastatic potential of PDAC cells.
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Affiliation(s)
| | | | | | | | | | - Jennifer M. Bailey-Lundberg
- Department of Anesthesiology, Critical Care, and Pain Medicine, McGovern Medical School, The University of Texas Health Science Center at Houston, Houston, TX, United States
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Li HX, Liang XY, Wu JH, Yuan YP, Gao Y, Cai SH. Simvastatin attenuates acute lung injury by activation of A2B adenosine receptor. Toxicol Appl Pharmacol 2021; 422:115460. [PMID: 33774062 DOI: 10.1016/j.taap.2021.115460] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/15/2020] [Revised: 01/13/2021] [Accepted: 02/10/2021] [Indexed: 12/31/2022]
Abstract
To explore the protective mechanism of simvastatin in acute lung injury (ALI), the lipopolysaccharide (LPS) induced (5 mg/kg) ALI rat model was used to examine the effects of simvastatin. Following simvastatin treatment, the histopathological evaluation of lung tissues was made using hematoxylin and eosin (H&E) staining. Also, myeloperoxidase (MPO) activity and the levels of tumor necrosis factor-alpha (TNF-α), interleukin-1 beta (IL-1β), and IL-10 were determined by ELISA. Blood gas analyses of arterial blood samples were performed to assess the pulmonary gas exchange. Moreover, the neutrophil count and total protein content were determined in the bronchoalveolar lavage (BAL) fluid. The ratio of wet lung to dry lung (W/D) and the alveolar fluid clearance (AFC) were calculated to estimate the severity of edema. Lastly, the levels of A2BAR, CFTR, claudin4, and claudin18 were also measured by qRT-PCR and Western blotting. Simvastatin treatment, in a dose-related manner, markedly improved the lung histological injury and decreased the levels of TNF-α, IL-1β, and increased IL-10 in LPS induced ALI. Also, pulmonary neutrophil count was alleviated. Besides, a decreased ratio of W/D lung also confirmed the simvastatin intervention. Notably, simvastatin reduced the levels of A2BAR, CFTR, and claudin18 but upregulated claudin4 in lung tissues. Additionally, treatment with PSB1115, an antagonist of A2BAR, countered the protective effect of simvastatin in ALI. Our study demonstrates that simvastatin has a protective effect against LPS-induced ALI by activating A2BAR and should be exploited as a novel therapeutic target for the treatment of ALI.
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Affiliation(s)
- Hong-Xia Li
- Department of Respiratory and Critical Care Medicine, The Second Medical Center, National Clinical Research Center for Geriatric Diseases, Chinese PLA General Hospital, Beijing 100853, China
| | - Xiao-Yan Liang
- Department of Respiratory Medicine in Special Wards, Chinese PLA General Hospital, Beijing 100853, China
| | - Jiong-He Wu
- Department of Respiratory and Critical Care Medicine, The Second Medical Center, National Clinical Research Center for Geriatric Diseases, Chinese PLA General Hospital, Beijing 100853, China
| | - Ya-Ping Yuan
- Department of Respiratory and Critical Care Medicine, The Second Medical Center, National Clinical Research Center for Geriatric Diseases, Chinese PLA General Hospital, Beijing 100853, China
| | - Yue Gao
- Beijing Institute of Radiation Medicine, AMMS, Haidian, Beijing 100039, China.
| | - Shao-Hua Cai
- Department of Respiratory Medicine in Special Wards, Chinese PLA General Hospital, Beijing 100853, China.
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3
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Silva D, Moreira D, Cordeiro-da-Silva A, Quintas C, Gonçalves J, Fresco P. Intracellular adenosine released from THP-1 differentiated human macrophages is involved in an autocrine control of Leishmania parasitic burden, mediated by adenosine A 2A and A 2B receptors. Eur J Pharmacol 2020; 885:173504. [PMID: 32858046 DOI: 10.1016/j.ejphar.2020.173504] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/14/2020] [Revised: 08/20/2020] [Accepted: 08/23/2020] [Indexed: 12/22/2022]
Abstract
Leishmania infected macrophages have conditions to produce adenosine. Despite its known immunosuppressive effects, no studies have yet established whether adenosine alter Leishmania parasitic burden upon macrophage infection. This work aimed at investigating whether endogenous adenosine exerts an autocrine modulation of macrophage response towards Leishmania infection, identifying its origin and potential pharmacological targets for visceral leishmaniasis (VL), using THP-1 differentiated macrophages. Adenosine deaminase treatment of infected THP-1 cells reduced the parasitic burden (29.1 ± 2.2%, P < 0.05). Adenosine A2A and A2B receptor subtypes expression was confirmed by RT-qPCR and by immunocytochemistry and their blockade with selective adenosine A2A and A2B antagonists reduced the parasitic burden [14.5 ± 3.1% (P < 0.05) and 12.3 ± 3.1% (P < 0.05), respectively; and 24.9 ± 2.8% (P < 0.05), by the combination of the two antagonists)], suggesting that adenosine A2 receptors are tonically activated in infected THP-1 differentiated macrophages. The tonic activation of adenosine A2 receptors was dependent on the release of intracellular adenosine through equilibrative nucleoside transporters (ENT1/ENT2): NBTI or dipyridamole reduced (~25%) whereas, when ENTs were blocked, adenosine A2 receptor antagonists failed to reduce and A2 agonists increase parasitic burden. Effects of adenosine A2 receptors antagonists and ENT1/2 inhibitor were prevented by L-NAME, indicating that nitric oxide production inhibition prevents adenosine from increasing parasitic burden. Results suggest that intracellular adenosine, released through ENTs, elicits an autocrine increase in parasitic burden in THP-1 macrophages, through adenosine A2 receptors activation. These observations open the possibility to use well-established ENT inhibitors or adenosine A2 receptor antagonists as new therapeutic approaches in VL.
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Affiliation(s)
- Dany Silva
- Laboratory of Pharmacology, Department of Drug Sciences, Faculty of Pharmacy, University of Porto, Rua Jorge Viterbo Ferreira 228, 4050-313, Porto, Portugal.
| | - Diana Moreira
- Parasite Disease Group, Institute of Molecular and Cellular Biology, Institute for Research and Innovation in Health Sciences, University of Porto, Rua Alfredo Allen 208, 4200-135, Porto, Portugal; Department of Biological Sciences, Faculty of Pharmacy, University of Porto, Rua Jorge Viterbo Ferreira 228, 4050-313, Porto, Portugal.
| | - Anabela Cordeiro-da-Silva
- Parasite Disease Group, Institute of Molecular and Cellular Biology, Institute for Research and Innovation in Health Sciences, University of Porto, Rua Alfredo Allen 208, 4200-135, Porto, Portugal; Department of Biological Sciences, Faculty of Pharmacy, University of Porto, Rua Jorge Viterbo Ferreira 228, 4050-313, Porto, Portugal.
| | - Clara Quintas
- Laboratory of Pharmacology, Department of Drug Sciences, Faculty of Pharmacy, University of Porto, Rua Jorge Viterbo Ferreira 228, 4050-313, Porto, Portugal.
| | - Jorge Gonçalves
- Laboratory of Pharmacology, Department of Drug Sciences, Faculty of Pharmacy, University of Porto, Rua Jorge Viterbo Ferreira 228, 4050-313, Porto, Portugal; Epithelial Interactions in Cancer, Institute of Molecular Pathology and Immunology, Institute for Research and Innovation in Health Sciences, University of Porto, Rua Alfredo Allen 208, 4200-135, Porto, Portugal.
| | - Paula Fresco
- Laboratory of Pharmacology, Department of Drug Sciences, Faculty of Pharmacy, University of Porto, Rua Jorge Viterbo Ferreira 228, 4050-313, Porto, Portugal.
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Pal China S, Pal S, Chattopadhyay S, Porwal K, Mittal M, Sanyal S, Chattopadhyay N. The wakefulness promoting drug Modafinil causes adenosine receptor-mediated upregulation of receptor activator of nuclear factor κB ligand in osteoblasts: Negative impact of the drug on peak bone accrual in rats. Toxicol Appl Pharmacol 2018; 348:22-31. [PMID: 29649498 DOI: 10.1016/j.taap.2018.04.006] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/24/2017] [Revised: 04/02/2018] [Accepted: 04/04/2018] [Indexed: 12/16/2022]
Abstract
Modafinil is primarily prescribed for treatment of narcolepsy and other sleep-associated disorders. However, its off-prescription use as a cognition enhancer increased considerably, specially among youths. Given its increasing use in young adults the effect of modafinil on peak bone accrual is an important issue but has never been investigated. Modafinil treatment to young male rats caused trabecular and cortical bone loss in tibia and femur, and reduction in biomechanical strength. Co-treatment of modafinil with alendronate (a drug that suppresses bone resorption) reversed the trabecular bone loss but failed to prevent cortical loss. Modafinil increased serum type 1 pro-collagen N-terminal protein (P1NP) and collagen type 1 cross-linked C-telopeptide (CTX-1) indicating a high turnover bone loss. The drug also increased receptor activator of nuclear factor κB ligand (RANKL) to osteoprotegerin (OPG) ratio in serum which likely resulted in increased osteoclast number per bone surface. Furthermore, conditioned medium from modafinil treated osteoblasts increased the expression of osteoclastogenic genes in bone marrow-derived macrophages and the effect was blocked by RANKL neutralizing antibody. In primary osteoblasts, modafinil stimulated cAMP production and using pharmacological approach, we showed that modafinil signalled via adenosine receptors (A2AR and A2BR) which resulted in increased RANKL expression. ZM-241,385 (an A2AR inhibitor) and MRS 1754 (an A2BR inhibitor) suppressed modafinil-induced upregulation of RANKL/OPG ratio in the calvarium of new born rat pups. Our data suggests that by activating osteoblast adenosine receptors modafinil increases the production of osteoclastogenic cytokine, RANKL that in turn results in high turnover bone loss in young rats.
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Affiliation(s)
- Shyamsundar Pal China
- Division of Endocrinology, Center for Research in Anabolic Skeletal Target in Health and Illness (ASTHI), Central Drug Research Institute (CDRI), Council of Scientific and Industrial Research (CSIR), Lucknow 226031, India; AcSIR, CSIR-Central Drug Research Institute Campus, Lucknow 226031, India
| | - Subhashis Pal
- Division of Endocrinology, Center for Research in Anabolic Skeletal Target in Health and Illness (ASTHI), Central Drug Research Institute (CDRI), Council of Scientific and Industrial Research (CSIR), Lucknow 226031, India
| | - Sourav Chattopadhyay
- AcSIR, CSIR-Central Drug Research Institute Campus, Lucknow 226031, India; Division of Biochemistry, CSIR-CDRI, Lucknow 226031, India
| | - Konica Porwal
- Division of Endocrinology, Center for Research in Anabolic Skeletal Target in Health and Illness (ASTHI), Central Drug Research Institute (CDRI), Council of Scientific and Industrial Research (CSIR), Lucknow 226031, India
| | - Monika Mittal
- Division of Endocrinology, Center for Research in Anabolic Skeletal Target in Health and Illness (ASTHI), Central Drug Research Institute (CDRI), Council of Scientific and Industrial Research (CSIR), Lucknow 226031, India; AcSIR, CSIR-Central Drug Research Institute Campus, Lucknow 226031, India
| | - Sabyasachi Sanyal
- AcSIR, CSIR-Central Drug Research Institute Campus, Lucknow 226031, India; Division of Biochemistry, CSIR-CDRI, Lucknow 226031, India
| | - Naibedya Chattopadhyay
- Division of Endocrinology, Center for Research in Anabolic Skeletal Target in Health and Illness (ASTHI), Central Drug Research Institute (CDRI), Council of Scientific and Industrial Research (CSIR), Lucknow 226031, India; AcSIR, CSIR-Central Drug Research Institute Campus, Lucknow 226031, India.
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5
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Tan L, Zhao B, Ge FT, Sun DH, Yu T. Shockwaves Inhibit Chondrogenic Differentiation of Human Mesenchymal Stem Cells in Association with Adenosine and A2B Receptors. Sci Rep 2017; 7:14377. [PMID: 29085053 PMCID: PMC5662611 DOI: 10.1038/s41598-017-14875-y] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/13/2017] [Accepted: 09/12/2017] [Indexed: 11/09/2022] Open
Abstract
Extracorporeal shockwave therapy (ESWT) has emerged as the important choice for the treatment of many orthopedic disorders. Our previous mechanistic studies suggest that ESWT promoted osteogenesis of human mesenchymal stem cells (hMSCs) through mechanisms that involve adenosine 5'-triphosphate (ATP) release. In this study, we investigated the effect of ESWT on chondrogenesis of hMSCs. We demonstrate that ESWT treatment caused a significant release of adenosine from hMSCs; ESWT treatment increased the levels of A2B receptor (A2BR) in hMSCs under 3-D culture conditions. ESWT, exogenous adenosine and specialized A2BR agonist suppressed hMSC chondrogenic differentiation through downregulating the expressions of aggrecan (ACAN), Collagen Type I alpha 2(COL1A2), Collagen Type II alpha 1(COL2A1), Sex-Determining Region YBox 9 (SOX9) and Sex-Determining Region YBox 6 (SOX6). Selective A2BR antagonists induced chondrogenic differentiation of hMSCs. This study indicated that shockwave therapy inhibits hMSC chondrogenic differentiation through or partially through regulation of adenosine release and activation of A2B receptor under 3-D culture conditions.
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Affiliation(s)
- Lei Tan
- Department of Orthopedic Trauma, The first Hospital of Jilin University, Changchun, 130021, China
| | - Bin Zhao
- Department of Orthopedics, The Bin Zhou People's Hospital, Bin Zhou, 256600, China
| | - Fu-Tao Ge
- Department of Shockwave, The First Hospital of Jilin University, Changchun, 130021, China
| | - Da-Hui Sun
- Department of Orthopedic Trauma, The first Hospital of Jilin University, Changchun, 130021, China.
| | - Tiecheng Yu
- Department of Orthopedic Trauma, The first Hospital of Jilin University, Changchun, 130021, China.
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6
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Alnouri MW, Jepards S, Casari A, Schiedel AC, Hinz S, Müller CE. Selectivity is species-dependent: Characterization of standard agonists and antagonists at human, rat, and mouse adenosine receptors. Purinergic Signal 2015; 11:389-407. [PMID: 26126429 PMCID: PMC4529847 DOI: 10.1007/s11302-015-9460-9] [Citation(s) in RCA: 98] [Impact Index Per Article: 10.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/12/2014] [Accepted: 06/17/2015] [Indexed: 12/14/2022] Open
Abstract
Adenosine receptors (ARs) have emerged as new drug targets. The majority of data on affinity/potency and selectivity of AR ligands described in the literature has been obtained for the human species. However, preclinical studies are mostly performed in mouse or rat, and standard AR agonists and antagonists are frequently used for studies in rodents without knowing their selectivity in the investigated species. In the present study, we selected a set of frequently used standard AR ligands, 8 agonists and 16 antagonists, and investigated them in radioligand binding studies at all four AR subtypes, A1, A2A, A2B, and A3, of three species, human, rat, and mouse. Recommended, selective agonists include CCPA (for A1AR of rat and mouse), CGS-21680 (for A2A AR of rat), and Cl-IB-MECA (for A3AR of all three species). The functionally selective partial A2B agonist BAY60-6583 was found to additionally bind to A1 and A3AR and act as an antagonist at both receptor subtypes. The antagonists PSB-36 (A1), preladenant (A2A), and PSB-603 (A2B) displayed high selectivity in all three investigated species. MRS-1523 acts as a selective A3AR antagonist in human and rat, but is only moderately selective in mouse. The comprehensive data presented herein provide a solid basis for selecting suitable AR ligands for biological studies.
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MESH Headings
- Adenosine A1 Receptor Agonists/metabolism
- Adenosine A1 Receptor Agonists/pharmacology
- Adenosine A1 Receptor Antagonists/metabolism
- Adenosine A1 Receptor Antagonists/pharmacology
- Adenosine A2 Receptor Agonists/metabolism
- Adenosine A2 Receptor Agonists/pharmacology
- Adenosine A2 Receptor Antagonists/metabolism
- Adenosine A2 Receptor Antagonists/pharmacology
- Adenosine A3 Receptor Agonists/metabolism
- Adenosine A3 Receptor Agonists/pharmacology
- Adenosine A3 Receptor Antagonists/metabolism
- Adenosine A3 Receptor Antagonists/pharmacology
- Animals
- Arrestin/metabolism
- Binding, Competitive/drug effects
- CHO Cells
- Cell Membrane/drug effects
- Cell Membrane/metabolism
- Cricetinae
- Cricetulus
- Cyclic AMP/metabolism
- DNA, Complementary/drug effects
- DNA, Complementary/genetics
- Humans
- Mice
- Rats
- Receptor, Adenosine A2A/drug effects
- Receptor, Adenosine A2A/genetics
- Receptor, Adenosine A2A/metabolism
- Receptor, Adenosine A2B/drug effects
- Receptor, Adenosine A2B/genetics
- Receptor, Adenosine A2B/metabolism
- Receptors, Purinergic P1/drug effects
- Receptors, Purinergic P1/genetics
- Receptors, Purinergic P1/metabolism
- Species Specificity
- Structure-Activity Relationship
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Affiliation(s)
- Mohamad Wessam Alnouri
- Pharma Center Bonn, Pharmaceutical Institute, Pharmaceutical Chemistry I, University of Bonn, An der Immenburg 4, D-53121 Bonn, Germany
| | - Stephan Jepards
- Pharma Center Bonn, Pharmaceutical Institute, Pharmaceutical Chemistry I, University of Bonn, An der Immenburg 4, D-53121 Bonn, Germany
| | - Alessandro Casari
- Pharma Center Bonn, Pharmaceutical Institute, Pharmaceutical Chemistry I, University of Bonn, An der Immenburg 4, D-53121 Bonn, Germany
| | - Anke C. Schiedel
- Pharma Center Bonn, Pharmaceutical Institute, Pharmaceutical Chemistry I, University of Bonn, An der Immenburg 4, D-53121 Bonn, Germany
| | - Sonja Hinz
- Pharma Center Bonn, Pharmaceutical Institute, Pharmaceutical Chemistry I, University of Bonn, An der Immenburg 4, D-53121 Bonn, Germany
| | - Christa E. Müller
- Pharma Center Bonn, Pharmaceutical Institute, Pharmaceutical Chemistry I, University of Bonn, An der Immenburg 4, D-53121 Bonn, Germany
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7
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Yang Y, Qiu Y, Wang W, Xiao W, Liang H, Zhang C, Yang H, Teitelbaum DH, Sun LH, Yang H. Adenosine A2B receptor modulates intestinal barrier function under hypoxic and ischemia/reperfusion conditions. Int J Clin Exp Pathol 2014; 7:2006-2018. [PMID: 24966910 PMCID: PMC4069946] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Subscribe] [Scholar Register] [Received: 02/26/2014] [Accepted: 04/02/2014] [Indexed: 06/03/2023]
Abstract
BACKGROUND Intestinal barrier function failure from ischemia/reperfusion (I/R) and acute hypoxia has been implicated as a critical determinant in the predisposition to intestinal inflammation and a number of inflammatory disorders. Here, we identified the role of Adenosine A2B receptor (A2BAR) in the regulation of intestinal barrier function under I/R and acute hypoxic conditions. METHODS C57BL/6J mice were used, and were randomized into three groups: Sham, I/R, IR+PSB1115 (a specific A2BAR antagonist) groups. After surgery, the small bowel was harvested for immunohistochemical staining, RNA and protein content, and intestinal permeability analyses. Using an epithelial cell culture model, we investigated the influence of hypoxia on the epithelial function, and the role of A2BAR in the expressions of tight junction and epithelial permeability. The expressions of Claudin-1, occludin and ZO-1 were detected by RT-PCR and Western-Blot. Epithelial barrier function was assessed with transepithelial resistance (TER). RESULTS AND CONCLUSIONS The A2BAR antagonist, PSB1115, significantly increased tight junction protein expression after intestinal I/R or acute hypoxia conditions. PSB1115 also attenuated the disrupted distribution of TJ proteins. Furthermore, inhibition of A2BAR attenuated the decrease in TER induced by I/R or acute hypoxic conditions, and maintained intestinal barrier function. Antagonism of A2BAR activity improves intestinal epithelial structure and barrier function in a mouse model of intestinal I/R and a cell model of acute hypoxia. These findings support a potentially destructive role for A2BAR under intestinal I/R and acute hypoxic conditions.
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Affiliation(s)
- Yang Yang
- Department of General Surgery, Xinqiao Hospital, Third Military Medical UniversityChongqing, China
| | - Yuan Qiu
- Department of General Surgery, Xinqiao Hospital, Third Military Medical UniversityChongqing, China
| | - Wensheng Wang
- Department of General Surgery, Xinqiao Hospital, Third Military Medical UniversityChongqing, China
| | - Weidong Xiao
- Department of General Surgery, Xinqiao Hospital, Third Military Medical UniversityChongqing, China
| | - Hongyin Liang
- Department of General Surgery, Xinqiao Hospital, Third Military Medical UniversityChongqing, China
| | - Chaojun Zhang
- Department of General Surgery, Xinqiao Hospital, Third Military Medical UniversityChongqing, China
| | | | | | - Li-Hua Sun
- Department of General Surgery, Xinqiao Hospital, Third Military Medical UniversityChongqing, China
| | - Hua Yang
- Department of General Surgery, Xinqiao Hospital, Third Military Medical UniversityChongqing, China
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Abstract
PURPOSE OF REVIEW During critical illness, alterations of intestinal blood supply and inflammatory activation can result in severe intestinal hypoxia (limited oxygen availability). Conditions of hypoxia lead to the activation of a transcriptional program that is under the control of the transcription factor hypoxia-inducible factor (HIF). In many instances, HIF-dependent alterations of gene expression represent endogenous adaptive responses that dampen pathologic inflammation and could be targeted to treat intestinal injury. RECENT FINDINGS Post-translational stabilization of the HIF transcription factor and corresponding changes in gene expression are central to the resolution of intestinal injury. Examples for such responses that we discuss in this review include hypoxia-elicited increases in extracellular adenosine production and signaling, particularly through the A2B adenosine receptor, and intestinal protection provided by hypoxia-inducible netrin-1. SUMMARY The present review focuses on HIF-elicited anti-inflammatory pathways that result in intestinal protection during critical illness. Many of these pathways represent novel therapeutic targets for attenuating multiorgan failure and critical illness. Whereas these therapeutic approaches are currently being investigated in cell culture models or in genetic mouse models, we are optimistic that at least some of these novel targets can be translated from bench to bedside in the near future.
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Affiliation(s)
- Almut Grenz
- Mucosal Inflammation Program, Department of Anesthesiology, University of Colorado, Aurora, Colorado 80045, USA.
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9
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Breschi MC, Blandizzi C, Fogli S, Martinelli C, Adinolfi B, Calderone V, Camici M, Martinotti E, Nieri P. In vivo adenosine A(2B) receptor desensitization in guinea-pig airway smooth muscle: implications for asthma. Eur J Pharmacol 2007; 575:149-57. [PMID: 17716655 DOI: 10.1016/j.ejphar.2007.07.051] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/07/2007] [Revised: 06/28/2007] [Accepted: 07/17/2007] [Indexed: 11/17/2022]
Abstract
This study was aimed at characterizing the role of adenosine receptor subtypes in the contractility modulation of guinea-pig airway smooth muscle in normal and pathological settings. In vitro and in vivo experiments were performed by testing selective agonists and antagonists on isolated tracheal smooth muscle preparations and pulmonary inflation pressure, respectively, under normal conditions or following ovalbumin-induced allergic sensitization. In normal and sensitized animals, the adenosine A(2A)/A(2B) receptor agonist, NECA, evoked relaxing responses of isolated tracheal preparations precontracted with histamine, and such an effect was reversed by the adenosine A(2B) antagonist, MRS 1706, in the presence or in the absence of epithelium. The expression of mRNA coding for adenosine A(2B) receptors was demonstrated in tracheal specimens. In vitro desensitization with 100 microM NECA markedly reduced the relaxing effect of the agonist. In vivo NECA or adenosine administration to normal animals inhibited histamine-mediated bronchoconstriction, while these inhibitory effects no longer occurred in sensitized guinea-pigs. Adenosine plasma levels were significantly higher in sensitized than normal animals. In conclusion, our data demonstrate that: (i) adenosine A(2B) receptors are responsible for the relaxing effects of adenosine on guinea-pig airways; (ii) these receptors can undergo rapid adaptive changes that may affect airway smooth muscle responsiveness to adenosine; (iii) ovalbumin-induced sensitization promotes a reversible inactivation of adenosine A(2B) receptors which can be ascribed to homologous desensitization. These findings can be relevant to better understand adenosine functions in airways as well as mechanisms of action of asthma therapies targeting the adenosine system.
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Affiliation(s)
- Maria Cristina Breschi
- Department of Psychiatry, Neurobiology, Pharmacology and Biotechnology, University of Pisa, Via Bonanno 6, I-56126, Pisa, Italy.
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10
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Eckle T, Krahn T, Grenz A, Köhler D, Mittelbronn M, Ledent C, Jacobson MA, Osswald H, Thompson LF, Unertl K, Eltzschig HK. Cardioprotection by ecto-5'-nucleotidase (CD73) and A2B adenosine receptors. Circulation 2007; 115:1581-90. [PMID: 17353435 DOI: 10.1161/circulationaha.106.669697] [Citation(s) in RCA: 364] [Impact Index Per Article: 21.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
Abstract
BACKGROUND Ecto-5'-nucleotidase (CD73)-dependent adenosine generation has been implicated in tissue protection during acute injury. Once generated, adenosine can activate cell-surface adenosine receptors (A1 AR, A2A AR, A2B AR, A3 AR). In the present study, we define the contribution of adenosine to cardioprotection by ischemic preconditioning. METHODS AND RESULTS On the basis of observations of CD73 induction by ischemic preconditioning, we found that inhibition or targeted gene deletion of cd73 abolished infarct size-limiting effects. Moreover, 5'-nucleotidase treatment reconstituted cd73-/- mice and attenuated infarct sizes in wild-type mice. Transcriptional profiling of adenosine receptors suggested a contribution of A2B AR because it was selectively induced by ischemic preconditioning. Specifically, in situ ischemic preconditioning conferred cardioprotection in A1 AR-/-, A2A AR-/-, or A3 AR-/- mice but not in A2B AR-/- mice or in wild-type mice after inhibition of the A2B AR. Moreover, A2B AR agonist treatment significantly reduced infarct sizes after ischemia. CONCLUSIONS Taken together, pharmacological and genetic evidence demonstrate the importance of CD73-dependent adenosine generation and signaling through A2B AR for cardioprotection by ischemic preconditioning and suggests 5'-nucleotidase or A2B AR agonists as therapy for myocardial ischemia.
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Affiliation(s)
- Tobias Eckle
- Department of Anesthesiology and Intensive Care Medicine, Tübingen University Hospital, Hoppe-Seyler-Str 3, D-72076 Tübingen, Germany
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Bevan N, Butchers PR, Cousins R, Coates J, Edgar EV, Morrison V, Sheehan MJ, Reeves J, Wilson DJ. Pharmacological characterisation and inhibitory effects of (2R,3R,4S,5R)-2-(6-amino-2-{[(1S)-2-hydroxy-1-(phenylmethyl)ethyl]amino}-9H-purin-9-yl)-5-(2-ethyl-2H-tetrazol-5-yl)tetrahydro-3,4-furandiol, a novel ligand that demonstrates both adenosine A(2A) receptor agonist and adenosine A(3) receptor antagonist activity. Eur J Pharmacol 2007; 564:219-25. [PMID: 17382926 DOI: 10.1016/j.ejphar.2007.01.094] [Citation(s) in RCA: 24] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/14/2006] [Revised: 01/27/2007] [Accepted: 01/31/2007] [Indexed: 11/21/2022]
Abstract
The pharmacological properties of the novel ligand, (2R,3R,4S,5R)-2-(6-amino-2-{[(1S)-2-hydroxy-1-(phenylmethyl)ethyl]amino}-9H-purin-9-yl)-5-(2-ethyl-2H-tetrazol-5-yl)tetrahydro-3,4-furandiol (I), at the human adenosine receptors were investigated using Chinese hamster ovary cell lines recombinantly expressing these receptors. Functional studies were performed using a cyclic AMP-coupled reporter gene system. Binding studies were performed using membranes from these cells. The effects of ligand (I) were also determined on functional responses of human neutrophils and eosinophils. Ligand (I) had a high affinity for the adenosine A(2A) receptor (pKi 7.8+/-0.2) and was a potent agonist at this receptor (pEC(50) 9.0+/-0.2). Ligand (I) had a similar affinity for the adenosine A(3) receptor (pKi 7.8+/-0.1) but displayed no agonist activity, acting instead as a competitive antagonist (pA(2) 8.3+/-0.04). Ligand (I) had lower affinity for adenosine A(1) and A(2B) receptors (pKi</=6) and showed relatively weak agonist activity at these receptors (pEC(50) 7.1 at both receptors). Ligand (I) was a potent inhibitor of the generation of reactive oxygen species from human neutrophils and eosinophils (pEC(50) 9.7+/-0.1 and 9.4+/-0.2 respectively). The inhibitory effect of ligand (I) on the release of reactive oxygen species from neutrophils was antagonised competitively by the adenosine A(2A) receptor antagonist 9-chloro-2-(2-furanyl)-[1,2,4]triazolo[1,5-c]quinazolin-5-amine (CGS15943) with a pA(2) value (10.03+/-0.44) consistent with an effect on adenosine A(2A) receptors. Ligand (I) also inhibited the release of granule proteins from neutrophils and eosinophils (pEC(50) 8.7 and 8.9 respectively), albeit less potently than as an inhibitor of reactive oxygen species generation. In summary, ligand (I) is a potent and selective agonist for the adenosine A(2A) receptor and a competitive antagonist at the adenosine A(3) receptor. Ligand (I) has potent anti-inflammatory effects on human granulocytes in vitro.
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Affiliation(s)
- Nicola Bevan
- Department of Screening and Compound Profiling, GlaxoSmithKline, New Frontiers Science Park, Third Avenue, Harlow, UK
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12
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Conde SV, Obeso A, Vicario I, Rigual R, Rocher A, Gonzalez C. Caffeine inhibition of rat carotid body chemoreceptors is mediated by A2A and A2B adenosine receptors. J Neurochem 2006; 98:616-28. [PMID: 16805851 DOI: 10.1111/j.1471-4159.2006.03912.x] [Citation(s) in RCA: 58] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/01/2022]
Abstract
Caffeine, an unspecific antagonist of adenosine receptors, is commonly used to treat the apnea of prematurity. We have defined the effects of caffeine on the carotid body (CB) chemoreceptors, the main peripheral controllers of breathing, and identified the adenosine receptors involved. Caffeine inhibited basal (IC50, 210 microm) and low intensity (PO2 approximately 66 mm Hg/30 mm K+) stimulation-induced release of catecholamines from chemoreceptor cells in intact preparations of rat CB in vitro. Opposite to caffeine, 5'-(N-ethylcarboxamido)adenosine (NECA; an A2 agonist) augmented basal and low-intensity hypoxia-induced release. 2-p-(2-Carboxyethyl)phenethyl-amino-5'-N-ethylcaboxamido-adenosine hydrochloride (CGS21680), 2-hexynyl-NECA (HE-NECA) and SCH58621 (A2A receptors agents) neither affected catecholamine release nor altered the caffeine effects. The 8-cycle-1,3-dipropylxanthine (DPCPX; an A1/A2B antagonist) and 8-(4-{[(4-cyanophenyl)carbamoylmethyl]-oxy}phenyl)-1,3-di(n-propyl)xanthine (MRS1754; an A2B antagonist) mimicking of caffeine indicated that caffeine effects are mediated by A2B receptors. Immunocytochemical A2B receptors were located in tyrosine hydroxylase positive chemoreceptor cells. Caffeine reduced by 52% the chemosensory discharges elicited by hypoxia in the carotid sinus nerve. Inhibition had two components with pharmacological analysis indicating that A2A and A2B receptors mediate, respectively, the low (17 x 10(-9) m) and high (160 x 10(-6) m) IC50 effects. It is concluded that endogenous adenosine, via presynaptic A2B and postsynaptic A2A receptors, can exert excitatory effects on the overall output of the rat CB chemoreceptors.
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Affiliation(s)
- S V Conde
- Departamento de Bioquímica y Biología Molecular y Fisiología/Instituto de Biología y Genética Molecular, Universidad de Valladolid/Consejo Superior de Investigaciones Científicas, Facultad de Medicina, Valladolid, Spain
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13
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Abstract
Adenosine in a signaling nucleoside eliciting many physiological responses. Elevated levels of adenosine have been found in bronchoalveolar lavage, blood and exhaled breath condensate of patients with asthma a condition characterized by chronic airway inflammation. In addition, inhaled adenosine-5'-monophosphate induces bronchoconstriction in asthmatics but not in normal subjects. Studies on animals and humans have shown that bronchoconstriction is most likely due to the release of inflammatory mediators from mast cells. However a number of evidences suggest that adenosine modulates the function of many other cells involved in airway inflammation such as neutrophils, eosinophils, lymphocytes and macrophages. Although this clear pro-inflammatory role in the airways, adenosine may activate also protective mechanisms particularly against lung injury. For many years this dual role of adenosine in the respiratory system has represented an enigma, and only recently it has become clear that biological functions of adenosine are mediated by four distinct subtypes of receptors (A1, A2A, A2B, and A3) and that biological responses are determined by the different pattern of receptors distribution in specific cells. Therefore, pharmacological modulation of adenosine receptors, particularly A2B, may represent a novel therapeutic approach for inflammatory diseases. Moreover, as bronchial response to adenosine strictly reflects airway inflammation in asthma, bronchial challenge with adenosine is considered a valuable clinical tool to monitor airway inflammation, to follow the response to anti-inflammatory treatments and to help in the diagnostic discrimination between asthma and chronic obstructive lung disease.
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MESH Headings
- Adenosine/metabolism
- Adenosine/pharmacology
- Animals
- Anti-Inflammatory Agents/pharmacology
- Asthma/diagnosis
- Asthma/drug therapy
- Asthma/physiopathology
- Bronchial Hyperreactivity/metabolism
- Bronchial Hyperreactivity/physiopathology
- Bronchoconstriction/drug effects
- Diagnosis, Differential
- Humans
- Pulmonary Disease, Chronic Obstructive/diagnosis
- Pulmonary Disease, Chronic Obstructive/metabolism
- Pulmonary Disease, Chronic Obstructive/physiopathology
- Receptor, Adenosine A1/drug effects
- Receptor, Adenosine A1/metabolism
- Receptor, Adenosine A2A/drug effects
- Receptor, Adenosine A2A/metabolism
- Receptor, Adenosine A2B/drug effects
- Receptor, Adenosine A2B/metabolism
- Respiratory System/metabolism
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Affiliation(s)
- Lucia Spicuzza
- Dipartimento di Medicina Interna e Medicina Specialistica Sezione Malattie Respiratorie-Università di Catania, Italy.
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14
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Talaia C, Queiroz G, Quintas C, Gonçalves J. Interaction between adenosine A 2B-receptors and alpha2-adrenoceptors on the modulation of noradrenaline release in the rat vas deferens: possible involvement of a group 2 adenylyl cyclase isoform. Neurochem Int 2005; 47:418-29. [PMID: 16040158 DOI: 10.1016/j.neuint.2005.05.013] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/01/2005] [Accepted: 05/24/2005] [Indexed: 11/19/2022]
Abstract
In the prostatic portion of rat vas deferens, activation of adenosine A 2B-receptors, beta2-adrenoceptors, adenylyl cyclase or protein kinase A caused a facilitation of noradrenaline release. Blockade of alpha2-adrenoceptors with yohimbine (1 microM) attenuated the facilitation mediated by adenosine A 2B-receptors and by direct activation of adenylyl cyclase with forskolin but not that mediated by beta2-adrenoceptors or by direct activation of protein kinase A with 8-bromoadenosine-3',5'-cyclicAMP. The adenosine A 2B- and the beta2-adrenoceptor-mediated facilitation was prevented by the adenylyl cyclase inhibitors, 2',5'-dideoxy-adenosine (3 microM) and 9-cyclopentyladenine (100 microM), at concentrations that also attenuated the release enhancing effect of forskolin, but were not changed by the phospholipase C inhibitor 1-[6-[((17beta)-3-methoxyestra-1,3,5[10]-trien-17-yl)amino]hexyl]-1H-pyrrole-2,5-dione (U-73122, 1 microM). Facilitation of noradrenaline release mediated by adenosine A 2B-receptors was also attenuated by activation of protein kinase C with the phorbol ester 12-myristate 13-acetate (1 microM) and by inhibition of Gbetagamma subunits with an anti-betagamma peptide; facilitation mediated by beta2-adrenoceptors was mainly attenuated by the calmodulin inhibitor calmidazolium (10 microM) and by the calmodulin kinase II inhibitor (N-[2-[N-(4-chlorocinnamyl)-N-methylaminomethyl]phenyl]-N-(2-hydroxyethyl)-4-methoxybenzene-sulfonamide phosphate (KN-93, 5 microM). The results suggest that adenosine A 2B- but not beta2-adrenoceptor-mediated facilitation of noradrenaline release is enhanced by an ongoing activation of alpha2-adrenoceptors. They further suggest that adenosine A 2B-receptors and beta2-adrenoceptors are coupled to distinct adenylyl cyclase isoforms what may explain the different influence of alpha2-adrenoceptor signalling pathway on the facilitatory effects mediated by the two adenylyl cyclase coupled receptors.
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Affiliation(s)
- Carlos Talaia
- Laboratório de Farmacologia, Faculdade de Farmácia, Universidade do Porto, Rua Aníbal Cunha, 164, 4050-047 Porto, Portugal
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15
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Abstract
Allosteric modulators for adenosine receptors (ARs) are of an increasing interest and may have potential therapeutic advantage over orthosteric ligands. Benzoylthiophene derivatives (including PD 81,723), 2-aminothiazolium salts, and related allosteric modulators of the A(1) AR have been studied. The benzoylthiophene derivatives were demonstrated to be selective enhancers for the A(1) AR, with little or no effect on other subtypes of ARs. Allosteric modulation of the A(2A) AR has also been reported. A(3) allosteric enhancers may be predicted to be useful against ischemic conditions. We have recently characterized two classes of A(3) AR allosteric modulators: 3-(2-pyridinyl)isoquinolines (e.g. VUF5455) and 1H-imidazo-[4,5-c]quinolin-4-amines (e.g. DU124183), which selectively decreased the agonist dissociation rate at the human A(3)AR but not at A(1) and A(2A) ARs. DU124183 left-shifted the agonist conc.-response curve for inhibition of forskolin-stimulated cAMP accumulation in intact cells expressing the human A(3)AR with up to 30% potentiation of the maximal efficacy. The increased potency of A(3) agonists was evident only in the presence of an A(3) antagonist, since VUF5455 and DU124183 also antagonized, i.e. displaced binding at the orthosteric site, with K(i) values of 1.68 and 0.82 microM, respectively. A(3)AR mutagenesis studies implicated F182(5.43) and N274(7.45) in the action of the enhancers and was interpreted using a rhodopsin-based A(3)AR molecular model, suggesting multiple binding modes. Amiloride analogues, SCH-202676 (N-(2,3-diphenyl-1,2,4-thiadiazol-5(2H)-ylidene)methanamine), and sodium ions were demonstrated to be common allosteric modulators for at least three subtypes (A(1), A(2A), and A(3)) of ARs.
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MESH Headings
- Animals
- Humans
- Models, Molecular
- Mutagenesis
- Receptor, Adenosine A1/chemistry
- Receptor, Adenosine A1/drug effects
- Receptor, Adenosine A2A/chemistry
- Receptor, Adenosine A2A/drug effects
- Receptor, Adenosine A2B/chemistry
- Receptor, Adenosine A2B/drug effects
- Receptors, Purinergic P1/chemistry
- Receptors, Purinergic P1/drug effects
- Receptors, Purinergic P1/genetics
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Affiliation(s)
- Zhan-Guo Gao
- Molecular Recognition Section, Laboratory of Bioorganic Chemistry, NIDDK, National Inst. of Health, Bethesda, Maryland 20892-0810, USA.
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16
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Gao ZG, Mamedova LK, Chen P, Jacobson KA. 2-Substituted adenosine derivatives: affinity and efficacy at four subtypes of human adenosine receptors. Biochem Pharmacol 2004; 68:1985-93. [PMID: 15476669 PMCID: PMC3408601 DOI: 10.1016/j.bcp.2004.06.011] [Citation(s) in RCA: 41] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/17/2004] [Accepted: 06/15/2004] [Indexed: 10/26/2022]
Abstract
The affinity and efficacy at four subtypes (A(1), A(2A), A(2B) and A(3)) of human adenosine receptors (ARs) of a wide range of 2-substituted adenosine derivatives were evaluated using radioligand binding assays and a cyclic AMP functional assay in intact CHO cells stably expressing these receptors. Similar to previous studies of the N(6)-position, several 2-substituents were found to be critical structural determinants for the A(3)AR activation. The following adenosine 2-ethers were moderately potent partial agonists (K(i), nM): benzyl (117), 3-chlorobenzyl (72), 2-(3-chlorophenyl)ethyl (41), and 2-(2-naphthyl)ethyl (130). The following adenosine 2-ethers were A(3)AR antagonists: 2,2-diphenylethyl, 2-(2-norbornan)ethyl, R- and S-2-phenylbutyl, and 2-(2-chlorophenyl)ethyl. 2-(S-2-Phenylbutyloxy)adenosine as an A(3)AR antagonist right-shifted the concentration-response curve for the inhibition by NECA of cyclic AMP accumulation with a K(B) value of 212 nM, which is similar to its binding affinity (K(i) = 175 nM). These 2-substituted adenosine derivatives were generally less potent at the A(1)AR in comparison to the A(3)AR, but fully efficacious, with binding K(i) values over 100 nM. The 2-phenylethyl moiety resulted in higher A(3)AR affinity (K(i) in nM) when linked to the 2-position of adenosine through an ether group (54), than when linked through an amine (310) or thioether (1960). 2-[2-(l-Naphthyl)ethyloxy]adenosine (K(i) = 3.8 nM) was found to be the most potent and selective (>50-fold) A(2A) agonist in this series. Mixed A(2A)/A(3)AR agonists have been identified. Interestingly, although most of these compounds were extremely weak at the A(2B)AR, 2-[2-(2-naphthyl)ethyloxy]adenosine (EC(50) = 1.4 microM) and 2-[2-(2-thienyl)-ethyloxy]adenosine (EC(50) = 1.8 microM) were found to be relatively potent A(2B) agonists, although less potent than NECA (EC(50) = 140 nM).
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MESH Headings
- Adenosine/analogs & derivatives
- Adenosine/chemistry
- Adenosine/pharmacology
- Animals
- CHO Cells
- Cricetinae
- Female
- Humans
- Receptor, Adenosine A1/drug effects
- Receptor, Adenosine A1/metabolism
- Receptor, Adenosine A2A/drug effects
- Receptor, Adenosine A2A/metabolism
- Receptor, Adenosine A2B/drug effects
- Receptor, Adenosine A2B/metabolism
- Receptor, Adenosine A3/drug effects
- Receptor, Adenosine A3/metabolism
- Receptors, Purinergic P1/drug effects
- Receptors, Purinergic P1/metabolism
- Structure-Activity Relationship
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Affiliation(s)
- Zhan-Guo Gao
- Molecular Recognition Section, Laboratory of Bioorganic Chemistry, National Institute of Diabetes and Digestive and Kidney Diseases, National Institutes of Health, Bethesda, MD 20892, USA
| | - Liaman K. Mamedova
- Molecular Recognition Section, Laboratory of Bioorganic Chemistry, National Institute of Diabetes and Digestive and Kidney Diseases, National Institutes of Health, Bethesda, MD 20892, USA
| | - Peiran Chen
- Molecular Recognition Section, Laboratory of Bioorganic Chemistry, National Institute of Diabetes and Digestive and Kidney Diseases, National Institutes of Health, Bethesda, MD 20892, USA
| | - Kenneth A. Jacobson
- Molecular Recognition Section, Laboratory of Bioorganic Chemistry, National Institute of Diabetes and Digestive and Kidney Diseases, National Institutes of Health, Bethesda, MD 20892, USA
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17
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Abstract
The discovery of antagonistic interactions between A2A adenosine receptors and D2 dopamine receptors in the ventral striatum suggested that A2A receptor activation might modulate the antipsychotic effects of dopamine receptor antagonists and could provide an opportunity for the development of A2A receptor agonists as novel antipsychotic drugs. However, there is limited evidence from preclinical and clinical studies that A2A receptor agonists can exert antipsychotic effects. Furthermore, it remains unclear whether A2A receptor agonists possess a sufficient safety margin or whether their potent hypotensive effects or extrapyramidal side effects would limit their therapeutic utility as antipsychotic agents. The interaction between A2A receptors and D2 receptors also raises the possibility that A2A receptor antagonists, which hold considerable promise as antiparkinsonian agents, may have dose-limiting psychotomimetic side effects. Preclinical studies using selective A2A receptor antagonists suggest that this class of compound has a low propensity to elicit psychotomimetic side effects or exacerbate those induced by D2 receptor agonists.
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18
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Rees DA, Lewis BM, Lewis MD, Francis K, Scanlon MF, Ham J. Adenosine-induced IL-6 expression in pituitary folliculostellate cells is mediated via A2b adenosine receptors coupled to PKC and p38 MAPK. Br J Pharmacol 2003; 140:764-72. [PMID: 14504137 PMCID: PMC1574075 DOI: 10.1038/sj.bjp.0705488] [Citation(s) in RCA: 35] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022] Open
Abstract
Activation of adenosine receptors in folliculostellate (FS) cells of the pituitary gland leads to the secretion of IL-6 and vascular endothelial growth factor (VEGF). We investigated the action of adenosine A2 receptor agonists on IL-6 and VEGF secretion in two murine FS cell lines (TtT/GF and Tpit/F1), and demonstrated a rank order of potency, 5'-N-ethylcarboxamidoadenosine (NECA)>2-p-(2-carboxyethyl)phenethylamino-5'-N-ethylcarboxamidoadenosine>adenosine, suggesting mediation via the A2b receptor. NECA-mediated IL-6 release was inhibited by the PLC inhibitor 1-[6-((17beta-3-methoxyestra-1,3,5(10)-tiene-17-yl)amino)hexyl]-1H-pyrrole-2,5-dione, the PI3 kinase inhibitor wortmannin and the PKC inhibitors bisindolylmaleimide 1 and bisindolymaleimide X1 HCl (Ro-32-0432). NECA-mediated IL-6 release was attenuated (<50%) by the extracellular signal-regulated kinase MAPK inhibitor 2'-amino-3'-methoxyflavone, and completely (>95%) inhibited by the p38 MAPK inhibitor 4-(4-fluorophenyl)-2-(4-methylsulphinylphenyl)-5-(4-pyridyl)1H-imidazole. NECA stimulates p38 MAPK phosphorylation that is inhibited by Ro-32-0432 but not by wortmannin. Dexamethasone inhibits NECA-stimulated IL-6 and VEGF secretion. These findings indicate that adenosine can stimulate IL-6 secretion in FS cells via the A2b receptor coupled principally to PLC/PKC and p38 MAPK; such an action may be important in the modulation of inflammatory response processes in the pituitary gland.
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Affiliation(s)
- D Aled Rees
- Department of Medicine, University of Wales College of Medicine, Heath Park, Cardiff CF14 4XN
| | - B Mary Lewis
- Department of Medicine, University of Wales College of Medicine, Heath Park, Cardiff CF14 4XN
| | - Mark D Lewis
- Department of Medicine, University of Wales College of Medicine, Heath Park, Cardiff CF14 4XN
| | - Karen Francis
- Department of Medicine, University of Wales College of Medicine, Heath Park, Cardiff CF14 4XN
| | - Maurice F Scanlon
- Department of Medicine, University of Wales College of Medicine, Heath Park, Cardiff CF14 4XN
| | - Jack Ham
- Department of Medicine, University of Wales College of Medicine, Heath Park, Cardiff CF14 4XN
- Author for correspondence:
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