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Thai BS, Chia LY, Nguyen ATN, Qin C, Ritchie RH, Hutchinson DS, Kompa A, White PJ, May LT. Targeting G protein-coupled receptors for heart failure treatment. Br J Pharmacol 2024; 181:2270-2286. [PMID: 37095602 DOI: 10.1111/bph.16099] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/26/2022] [Revised: 04/10/2023] [Accepted: 04/13/2023] [Indexed: 04/26/2023] Open
Abstract
Heart failure remains a leading cause of morbidity and mortality worldwide. Current treatment for patients with heart failure include drugs targeting G protein-coupled receptors such as β-adrenoceptor antagonists (β-blockers) and angiotensin II type 1 receptor antagonists (or angiotensin II receptor blockers). However, many patients progress to advanced heart failure with persistent symptoms, despite treatment with available therapeutics that have been shown to reduce mortality and mortality. GPCR targets currently being explored for the development of novel heart failure therapeutics include adenosine receptor, formyl peptide receptor, relaxin/insulin-like family peptide receptor, vasopressin receptor, endothelin receptor and the glucagon-like peptide 1 receptor. Many GPCR drug candidates are limited by insufficient efficacy and/or dose-limiting unwanted effects. Understanding the current challenges hindering successful clinical translation and the potential to overcome existing limitations will facilitate the future development of novel heart failure therapeutics. LINKED ARTICLES: This article is part of a themed issue Therapeutic Targeting of G Protein-Coupled Receptors: hot topics from the Australasian Society of Clinical and Experimental Pharmacologists and Toxicologists 2021 Virtual Annual Scientific Meeting. To view the other articles in this section visit http://onlinelibrary.wiley.com/doi/10.1111/bph.v181.14/issuetoc.
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Affiliation(s)
- Bui San Thai
- Drug Discovery Biology, Monash Institute of Pharmaceutical Sciences, Monash University, Parkville, Victoria, Australia
| | - Ling Yeong Chia
- Drug Discovery Biology, Monash Institute of Pharmaceutical Sciences, Monash University, Parkville, Victoria, Australia
| | - Anh T N Nguyen
- Drug Discovery Biology, Monash Institute of Pharmaceutical Sciences, Monash University, Parkville, Victoria, Australia
| | - Chengxue Qin
- Drug Discovery Biology, Monash Institute of Pharmaceutical Sciences, Monash University, Parkville, Victoria, Australia
| | - Rebecca H Ritchie
- Drug Discovery Biology, Monash Institute of Pharmaceutical Sciences, Monash University, Parkville, Victoria, Australia
| | - Dana S Hutchinson
- Drug Discovery Biology, Monash Institute of Pharmaceutical Sciences, Monash University, Parkville, Victoria, Australia
| | - Andrew Kompa
- Department Medicine and Radiology, University of Melbourne, St Vincent's Hospital, Fitzroy, Victoria, Australia
| | - Paul J White
- Drug Discovery Biology, Monash Institute of Pharmaceutical Sciences, Monash University, Parkville, Victoria, Australia
| | - Lauren T May
- Drug Discovery Biology, Monash Institute of Pharmaceutical Sciences, Monash University, Parkville, Victoria, Australia
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Gao ZG, Haddad M, Jacobson KA. A 2B adenosine receptor signaling and regulation. Purinergic Signal 2024:10.1007/s11302-024-10025-y. [PMID: 38833181 DOI: 10.1007/s11302-024-10025-y] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/23/2023] [Accepted: 05/20/2024] [Indexed: 06/06/2024] Open
Abstract
The A2B adenosine receptor (A2BR) is one of the four adenosine-activated G protein-coupled receptors. In addition to adenosine, protein kinase C (PKC) was recently found to activate the A2BR. The A2BR is coupled to both Gs and Gi, as well as Gq proteins in some cell types. Many primary cells and cell lines, such as bladder and breast cancer, bronchial smooth muscle, skeletal muscle, and fat cells, express the A2BR endogenously at high levels, suggesting its potentially important role in asthma, cancer, diabetes, and other conditions. The A2BR has been characterized as both pro- and anti-inflammatory, inducing cell type-dependent secretion of IL-6, IL-8, and IL-10. Theophylline and enprofylline have long been used for asthma treatment, although it is still not entirely clear if their A2BR antagonism contributes to their therapeutic effects or side effects. The A2BR is required in ischemic cardiac preconditioning by adenosine. Both A2BR and protein kinase C (PKC) contribute to cardioprotection, and both modes of A2BR signaling can be blocked by A2BR antagonists. Inhibitors of PKC and A2BR are in clinical cancer trials. Sulforaphane and other isothiocyanates from cruciferous vegetables such as broccoli and cauliflower have been reported to inhibit A2BR signaling via reaction with an intracellular A2BR cysteine residue (C210). A full, A2BR-selective agonist, critical to elucidate many controversial roles of the A2BR, is still not available, although agonist-bound A2BR structures have recently been reported.
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Affiliation(s)
- Zhan-Guo Gao
- Molecular Recognition Section, Laboratory of Bioorganic Chemistry, NIDDK, National Institutes of Health, 9000 Rockville Pike, Bethesda, MD, 20892, USA.
| | - Mansour Haddad
- Faculty of Pharmacy, Yarmouk University, Irbid, 21163, Jordan
| | - Kenneth A Jacobson
- Molecular Recognition Section, Laboratory of Bioorganic Chemistry, NIDDK, National Institutes of Health, 9000 Rockville Pike, Bethesda, MD, 20892, USA.
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3
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Stepanova M, Aherne CM. Adenosine in Intestinal Epithelial Barrier Function. Cells 2024; 13:381. [PMID: 38474346 DOI: 10.3390/cells13050381] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/23/2023] [Revised: 02/13/2024] [Accepted: 02/18/2024] [Indexed: 03/14/2024] Open
Abstract
At the intestinal front, several lines of defense are in place to resist infection and injury, the mucus layer, gut microbiome and strong epithelial junctions, to name a few. Their collaboration creates a resilient barrier. In intestinal disorders, such as inflammatory bowel disease (IBD), barrier function is compromised, which results in rampant inflammation and tissue injury. In response to the destruction, the intestinal epithelium releases adenosine, a small but powerful nucleoside that functions as an alarm signal. Amidst the chaos of inflammation, adenosine aims to restore order. Within the scope of its effects is the ability to regulate intestinal epithelial barrier integrity. This review aims to define the contributions of adenosine to mucus production, microbiome-dependent barrier protection, tight junction dynamics, chloride secretion and acid-base balance to reinforce its importance in the intestinal epithelial barrier.
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Affiliation(s)
- Mariya Stepanova
- Conway Institute of Biomolecular and Biomedical Research, University College Dublin, Belfield, Dublin 4, Ireland
- School of Medicine, University College Dublin, Belfield, Dublin 4, Ireland
| | - Carol M Aherne
- Conway Institute of Biomolecular and Biomedical Research, University College Dublin, Belfield, Dublin 4, Ireland
- School of Medicine, University College Dublin, Belfield, Dublin 4, Ireland
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Fisher C, Fallot LB, Wan TC, Keyes RF, Suresh RR, Rothwell AC, Gao ZG, McCorvy JD, Smith BC, Jacobson KA, Auchampach JA. Characterization of Dual-Acting A 3 Adenosine Receptor Positive Allosteric Modulators That Preferentially Enhance Adenosine-Induced Gα i3 and Gα oA Isoprotein Activation. ACS Pharmacol Transl Sci 2022; 5:625-641. [PMID: 35983277 PMCID: PMC9380209 DOI: 10.1021/acsptsci.2c00076] [Citation(s) in RCA: 8] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/20/2022] [Indexed: 12/19/2022]
Abstract
The A3 adenosine receptor (A3AR) is a promising therapeutic target for inflammatory diseases, cancer, and chronic neuropathic pain, with agonists already in advanced clinical trials. Here we report an in-depth comparison of the pharmacological properties and structure-activity relationships of existing and expanded compound libraries of 2-substituted 1H-imidazo[4,5-c]quinolin-4-amine and 4-amino-substituted quinoline derivatives that function as A3AR positive allosteric modulators (PAMs). We also show that our lead compound from each series enhances adenosine-induced A3AR signaling preferentially toward activation of Gαi3 and GαoA isoproteins, which are coexpressed with the A3AR in immune cells and spinal cord neurons. Finally, utilizing an extracellular/intracellular chimeric A3AR approach composed of sequences from a responding (human) and a nonresponding (mouse) species, we provide evidence in support of the idea that the imidazoquinolin-4-amine class of PAMs variably interacts dually with the orthosteric ligand binding site as well as with a separate allosteric site located within the inner/intracellular regions of the receptor. This study has advanced both structural and pharmacological understanding of these two classes of A3AR PAMs, which includes leads for future pharmaceutical development.
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Affiliation(s)
- Courtney
L. Fisher
- Department
of Pharmacology & Toxicology and the Cardiovascular Center, Medical College of Wisconsin, 8701 Watertown Plank Road, Milwaukee, Wisconsin 53226, United States
| | - Lucas B. Fallot
- Molecular
Recognition Section, Laboratory of Bioorganic Chemistry, National
Institute of Diabetes and Digestive and Kidney Diseases, National Institutes of Health, 9000 Rockville Pike, Bethesda, Maryland 20892, United States
- Department
of Biochemistry & Molecular Biology, Uniformed Services University of the Health Sciences, 4301 Jones Bridge Road, Bethesda, Maryland 20814, United States
- Department
of Chemistry & Life Science, United
States Military Academy, 646 Swift Road, West Point, New York 10996, United
States
| | - Tina C. Wan
- Department
of Pharmacology & Toxicology and the Cardiovascular Center, Medical College of Wisconsin, 8701 Watertown Plank Road, Milwaukee, Wisconsin 53226, United States
| | - Robert F. Keyes
- Department
of Biochemistry, Medical College of Wisconsin, 8701 Watertown Plank Road, Milwaukee, Wisconsin 53226, United States
| | - R. Rama Suresh
- Molecular
Recognition Section, Laboratory of Bioorganic Chemistry, National
Institute of Diabetes and Digestive and Kidney Diseases, National Institutes of Health, 9000 Rockville Pike, Bethesda, Maryland 20892, United States
| | - Amy C. Rothwell
- Department
of Pharmacology & Toxicology and the Cardiovascular Center, Medical College of Wisconsin, 8701 Watertown Plank Road, Milwaukee, Wisconsin 53226, United States
| | - Zhan-Guo Gao
- Molecular
Recognition Section, Laboratory of Bioorganic Chemistry, National
Institute of Diabetes and Digestive and Kidney Diseases, National Institutes of Health, 9000 Rockville Pike, Bethesda, Maryland 20892, United States
| | - John D. McCorvy
- Department
of Cell Biology, Neurobiology, & Anatomy, Medical College of Wisconsin, 8701 Watertown Plank Road, Milwaukee, Wisconsin 53226, United States
| | - Brian C. Smith
- Department
of Biochemistry, Medical College of Wisconsin, 8701 Watertown Plank Road, Milwaukee, Wisconsin 53226, United States
| | - Kenneth A. Jacobson
- Molecular
Recognition Section, Laboratory of Bioorganic Chemistry, National
Institute of Diabetes and Digestive and Kidney Diseases, National Institutes of Health, 9000 Rockville Pike, Bethesda, Maryland 20892, United States
| | - John A. Auchampach
- Department
of Pharmacology & Toxicology and the Cardiovascular Center, Medical College of Wisconsin, 8701 Watertown Plank Road, Milwaukee, Wisconsin 53226, United States
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Adenosine Receptor A2B Negatively Regulates Cell Migration in Ovarian Carcinoma Cells. Int J Mol Sci 2022; 23:ijms23094585. [PMID: 35562985 PMCID: PMC9100769 DOI: 10.3390/ijms23094585] [Citation(s) in RCA: 5] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/11/2022] [Revised: 04/14/2022] [Accepted: 04/20/2022] [Indexed: 12/15/2022] Open
Abstract
The purinergic system is fundamental in the tumor microenvironment, since it regulates tumor cell interactions with the immune system, as well as growth and differentiation in autocrine-paracrine responses. Here, we investigated the role of the adenosine A2B receptor (A2BR) in ovarian carcinoma-derived cells’ (OCDC) properties. From public databases, we documented that high A2BR expression is associated with a better prognostic outcome in ovarian cancer patients. In vitro experiments were performed on SKOV-3 cell line to understand how A2BR regulates the carcinoma cell phenotype associated with cell migration. RT-PCR and Western blotting revealed that the ADORA2B transcript (coding for A2BR) and A2BR were expressed in SKOV-3 cells. Stimulation with BAY-606583, an A2BR agonist, induced ERK1/2 phosphorylation, which was abolished by the antagonist PSB-603. Pharmacological activation of A2BR reduced cell migration and actin stress fibers; in agreement, A2BR knockdown increased migration and enhanced actin stress fiber expression. Furthermore, the expression of E-cadherin, an epithelial marker, increased in BAY-606583-treated cells. Finally, cDNA microarrays revealed the pathways mediating the effects of A2BR activation on SKOV-3 cells. Our results showed that A2BR contributed to maintaining an epithelial-like phenotype in OCDC and highlighted this purinergic receptor as a potential biomarker.
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Santiago AR, Madeira MH, Boia R, Aires ID, Rodrigues-Neves AC, Santos PF, Ambrósio AF. Keep an eye on adenosine: Its role in retinal inflammation. Pharmacol Ther 2020; 210:107513. [PMID: 32109489 DOI: 10.1016/j.pharmthera.2020.107513] [Citation(s) in RCA: 29] [Impact Index Per Article: 7.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/07/2023]
Abstract
Adenosine is an endogenous purine nucleoside ubiquitously distributed throughout the body that interacts with G protein-coupled receptors, classified in four subtypes: A1R, A2AR, A2BR and A3R. Among the plethora of functions of adenosine, it has been increasingly recognized as a key mediator of the immune response. Neuroinflammation is a feature of chronic neurodegenerative diseases and contributes to the pathophysiology of several retinal degenerative diseases. Animal models of retinal diseases are helping to elucidate the regulatory roles of adenosine receptors in the development and progression of those diseases. Mounting evidence demonstrates that the adenosinergic system is altered in the retina during pathological conditions, compromising retinal physiology. This review focuses on the roles played by adenosine and the elements of the adenosinergic system (receptors, enzymes, transporters) in the neuroinflammatory processes occurring in the retina. An improved understanding of the molecular and cellular mechanisms of the signalling pathways mediated by adenosine underlying the onset and progression of retinal diseases will pave the way towards the identification of new therapeutic approaches.
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Affiliation(s)
- Ana Raquel Santiago
- Faculty of Medicine, Coimbra Institute for Clinical and Biomedical Research (iCBR), University of Coimbra, 3000-548 Coimbra, Portugal; Center for Innovative Biomedicine and Biotechnology (CIBB), University of Coimbra, 3000-548 Coimbra, Portugal; Association for Innovation and Biomedical Research on Light and Image (AIBILI), Coimbra, 3000-548 Coimbra, Portugal.
| | - Maria H Madeira
- Faculty of Medicine, Coimbra Institute for Clinical and Biomedical Research (iCBR), University of Coimbra, 3000-548 Coimbra, Portugal; Center for Innovative Biomedicine and Biotechnology (CIBB), University of Coimbra, 3000-548 Coimbra, Portugal; Association for Innovation and Biomedical Research on Light and Image (AIBILI), Coimbra, 3000-548 Coimbra, Portugal
| | - Raquel Boia
- Faculty of Medicine, Coimbra Institute for Clinical and Biomedical Research (iCBR), University of Coimbra, 3000-548 Coimbra, Portugal; Center for Innovative Biomedicine and Biotechnology (CIBB), University of Coimbra, 3000-548 Coimbra, Portugal
| | - Inês Dinis Aires
- Faculty of Medicine, Coimbra Institute for Clinical and Biomedical Research (iCBR), University of Coimbra, 3000-548 Coimbra, Portugal; Center for Innovative Biomedicine and Biotechnology (CIBB), University of Coimbra, 3000-548 Coimbra, Portugal
| | - Ana Catarina Rodrigues-Neves
- Faculty of Medicine, Coimbra Institute for Clinical and Biomedical Research (iCBR), University of Coimbra, 3000-548 Coimbra, Portugal; Center for Innovative Biomedicine and Biotechnology (CIBB), University of Coimbra, 3000-548 Coimbra, Portugal
| | - Paulo Fernando Santos
- Faculty of Medicine, Coimbra Institute for Clinical and Biomedical Research (iCBR), University of Coimbra, 3000-548 Coimbra, Portugal; Center for Innovative Biomedicine and Biotechnology (CIBB), University of Coimbra, 3000-548 Coimbra, Portugal; Department of Life Sciences, University of Coimbra, 3000-456 Coimbra, Portugal
| | - António Francisco Ambrósio
- Faculty of Medicine, Coimbra Institute for Clinical and Biomedical Research (iCBR), University of Coimbra, 3000-548 Coimbra, Portugal; Center for Innovative Biomedicine and Biotechnology (CIBB), University of Coimbra, 3000-548 Coimbra, Portugal; Association for Innovation and Biomedical Research on Light and Image (AIBILI), Coimbra, 3000-548 Coimbra, Portugal.
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7
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The Role of Adenosine A2b Receptor in Mediating the Cardioprotection of Electroacupuncture Pretreatment via Influencing Ca 2+ Key Regulators. EVIDENCE-BASED COMPLEMENTARY AND ALTERNATIVE MEDICINE 2019; 2019:6721286. [PMID: 31885657 PMCID: PMC6925712 DOI: 10.1155/2019/6721286] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 07/25/2019] [Revised: 10/29/2019] [Accepted: 11/11/2019] [Indexed: 11/24/2022]
Abstract
Objective To investigate the roles played by A2b receptor and the key Ca2+ signaling components in the mediation of the cardioprotection of electroacupuncture pretreatment in the rats subjected to myocardial ischemia and reperfusion. Methods SD rats were randomly divided into a normal control (NC) group, ischemia/reperfusion model (M) group, electroacupuncture pretreatment (EA) group, and electroacupuncture pretreatment plus A2b antagonist (EAG) group. The ischemia/reperfusion model was made by ligation and loosening of the left descending branch of the coronary artery in all groups except the NC group. The EA group was pretreated with electroacupuncture at the Neiguan (PC6) point once a day for three consecutive days before the modeling. The elevation of the ST segment, arrhythmia scores, and myocardial infarction size of each group was measured. The relative expression levels of A2b, RyR2, SERCA2a, NCX1, P-PLB(S16)/PLB, and Troponin C/Troponin I proteins in the injured myocardium were detected by multiple fluorescence western blot. Results The level of ST segment, arrhythmia scores, and infarct size in the M group was significantly higher/larger than that in the NC group after ischemia and reperfusion, while all the three indices mentioned above in the EA group were significantly lower/smaller than those in the M group after reperfusion. The expression of the proteins of adenosine receptor 2b(A2b), ryanodine receptor 2(RyR2), and sarco(endo)plasmic reticulum Ca2+-ATPase 2a (SERCA2a) in the EA group was significantly enhanced as compared with the M group, while in the EAG group, the contents of A2b were significantly lower than those in the EA group, and RyR2 was higher in the EAG group. In comparison with the NC group, the relative expression of NCX1 protein in M, EA, and EAG groups was not changed significantly. The ratio of phosphorylated phospholamban (P-PLB) over phospholamban (PLB) in the M group was significantly lower than that in the NC group, and the ratio in the EA group was significantly increased as compared with the M group, while the ratio of Troponin C/Troponin I in the EA group was significantly decreased in comparison with that in other groups. Conclusion Electroacupuncture pretreatment could reduce ischemia and reperfusion-induced myocardial injury via possibly increasing the A2b content and regulating the key Ca2+ signaling components, namely inhibiting RyR2 and enhancing P-PLB(S16)/PLB ratio and SERCA2a proteins, so as to diminish the intracellular Ca2+ overload and consequently lessen the myocardial injury.
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Li J, Hong X, Li G, Conti PS, Zhang X, Chen K. PET Imaging of Adenosine Receptors in Diseases. Curr Top Med Chem 2019; 19:1445-1463. [PMID: 31284861 DOI: 10.2174/1568026619666190708163407] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/17/2018] [Revised: 01/26/2019] [Accepted: 02/02/2019] [Indexed: 01/08/2023]
Abstract
Adenosine receptors (ARs) are a class of purinergic G-protein-coupled receptors (GPCRs). Extracellular adenosine is a pivotal regulation molecule that adjusts physiological function through the interaction with four ARs: A1R, A2AR, A2BR, and A3R. Alterations of ARs function and expression have been studied in neurological diseases (epilepsy, Alzheimer's disease, and Parkinson's disease), cardiovascular diseases, cancer, and inflammation and autoimmune diseases. A series of Positron Emission Tomography (PET) probes for imaging ARs have been developed. The PET imaging probes have provided valuable information for diagnosis and therapy of diseases related to alterations of ARs expression. This review presents a concise overview of various ARs-targeted radioligands for PET imaging in diseases. The most recent advances in PET imaging studies by using ARs-targeted probes are briefly summarized.
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Affiliation(s)
- Jindian Li
- Department of Radiology, Molecular Imaging Center, Keck School of Medicine, University of Southern California, 2250 Alcazar Street, CSC103, Los Angeles, CA 90033, United States.,State Key Laboratory of Molecular Vaccinology and Molecular Diagnostics & Center for Molecular Imaging and Translational Medicine, School of Public Health, Xiamen University, Xiamen 361102, China
| | - Xingfang Hong
- Laboratory of Pathogen Biology, School of Basic Medical Sciences, Dali University, Dali 671000, China
| | - Guoquan Li
- Department of Radiology, Molecular Imaging Center, Keck School of Medicine, University of Southern California, 2250 Alcazar Street, CSC103, Los Angeles, CA 90033, United States
| | - Peter S Conti
- Department of Radiology, Molecular Imaging Center, Keck School of Medicine, University of Southern California, 2250 Alcazar Street, CSC103, Los Angeles, CA 90033, United States
| | - Xianzhong Zhang
- State Key Laboratory of Molecular Vaccinology and Molecular Diagnostics & Center for Molecular Imaging and Translational Medicine, School of Public Health, Xiamen University, Xiamen 361102, China
| | - Kai Chen
- Department of Radiology, Molecular Imaging Center, Keck School of Medicine, University of Southern California, 2250 Alcazar Street, CSC103, Los Angeles, CA 90033, United States
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Pal Y, Bandyopadhyay N, Pal RS, Ahmed S, Bandopadhyay S. Perspective and Potential of A2A and A3 Adenosine Receptors as Therapeutic Targets for the Treatment of Rheumatoid Arthritis. Curr Pharm Des 2019; 25:2859-2874. [DOI: 10.2174/1381612825666190710111658] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/30/2019] [Accepted: 07/01/2019] [Indexed: 01/10/2023]
Abstract
Adenosine is a purine nucleoside which is an effective controller of inflammation. The inflammatory effect of adenosine is expressed via its four receptor subtypes viz. A1, A2A, A2B and A3. The various inflammatory conditions including rheumatoid arthritis (RA) are initiated by adenosine receptors of which A2A and A3 play a vital role. RA primarily is an auto-immune disorder which is manifested as chronic inflammation in the synovial lining of joints. In order to develop an effective treatment, the role of cytokines, IL–1, TNF-α and IL–6 is crucial. Besides, the knowledge of PI3K-PKB/Akt and NF-kB signaling pathway is also important to understand the antiinflammatory targets. Methotrexate along with various other molecules like, NSAIDs and DMARDs are presently used as treatment lines for controlling RA. The enhanced knowledge of the preclinical stages and pathogenesis along with recent potent therapeutics raises the hopes that RA can be prevented in the near future.
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Affiliation(s)
- Yogendra Pal
- Department of Pharmacy, Pranveer Singh Institute of Technology, Bhauti, Kanpur, Uttar Pradesh 209305, India
| | - Nabamita Bandyopadhyay
- Molecular Biology Division, National Institute of Malarial Research (NIMR), Dwarka, New Delhi, Delhi 110077, India
| | - Rashmi S. Pal
- Department of Pharmacy, Pranveer Singh Institute of Technology, Bhauti, Kanpur, Uttar Pradesh 209305, India
| | - Sarfaraz Ahmed
- Global Institute of Pharmaceutical Education and Research, Kashipur, Udham Singh Nagar, Uttarakhand 244713, India
| | - Shantanu Bandopadhyay
- Faculty of Pharmacy, Naraina Vidya Peeth Group of Institutions, Panki, Kanpur, Uttar Pradesh 208020, India
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Patel W, Moore PJ, Sassano MF, Lopes-Pacheco M, Aleksandrov AA, Amaral MD, Tarran R, Gray MA. Increases in cytosolic Ca 2+ induce dynamin- and calcineurin-dependent internalisation of CFTR. Cell Mol Life Sci 2019; 76:977-994. [PMID: 30547226 PMCID: PMC6394554 DOI: 10.1007/s00018-018-2989-3] [Citation(s) in RCA: 12] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/18/2018] [Revised: 11/28/2018] [Accepted: 12/04/2018] [Indexed: 12/12/2022]
Abstract
The cystic fibrosis transmembrane conductance regulator (CFTR) is a cAMP-regulated, apical anion channel that regulates ion and fluid transport in many epithelia including the airways. We have previously shown that cigarette smoke (CS) exposure to airway epithelia causes a reduction in plasma membrane CFTR expression which correlated with a decrease in airway surface hydration. The effect of CS on CFTR was dependent on an increase in cytosolic Ca2+. However, the underlying mechanism for this Ca2+-dependent, internalisation of CFTR is unknown. To gain a better understanding of the effect of Ca2+ on CFTR, we performed whole cell current recordings to study the temporal effect of raising cytosolic Ca2+ on CFTR function. We show that an increase in cytosolic Ca2+ induced a time-dependent reduction in whole cell CFTR conductance, which was paralleled by a loss of cell surface CFTR expression, as measured by confocal and widefield fluorescence microscopy. The decrease in CFTR conductance and cell surface expression were both dynamin-dependent. Single channel reconstitution studies showed that raising cytosolic Ca2+ per se had no direct effect on CFTR. In fact, the loss of CFTR plasma membrane activity correlated with activation of calcineurin, a Ca2+-dependent phosphatase, suggesting that dephosphorylation of CFTR was linked to the loss of surface expression. In support of this, the calcineurin inhibitor, cyclosporin A, prevented the Ca2+-induced decrease in cell surface CFTR. These results provide a hitherto unrecognised role for cytosolic Ca2+ in modulating the residency of CFTR at the plasma membrane through a dynamin- and calcineurin-dependent mechanism.
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Affiliation(s)
- Waseema Patel
- Institute for Cell and Molecular Biosciences, Newcastle University, Newcastle upon Tyne, NE2 4HH, UK
- Marsico Lung Institute, The University of North Carolina at Chapel Hill, Chapel Hill, NC, USA
| | - Patrick J Moore
- Marsico Lung Institute, The University of North Carolina at Chapel Hill, Chapel Hill, NC, USA
| | - M Flori Sassano
- Marsico Lung Institute, The University of North Carolina at Chapel Hill, Chapel Hill, NC, USA
| | - Miquéias Lopes-Pacheco
- Faculty of Sciences, BioISI-Biosystems and Integrative Sciences Institute, University of Lisboa, Lisbon, Portugal
| | - Andrei A Aleksandrov
- Department of Biochemistry and Biophysics, Cystic Fibrosis Research and Treatment Center, The University of North Carolina at Chapel Hill, Chapel Hill, NC, USA
| | - Margarida D Amaral
- Faculty of Sciences, BioISI-Biosystems and Integrative Sciences Institute, University of Lisboa, Lisbon, Portugal
| | - Robert Tarran
- Marsico Lung Institute, The University of North Carolina at Chapel Hill, Chapel Hill, NC, USA
- Department of Cell Biology and Physiology, Cystic Fibrosis Research and Treatment Center, The University of North Carolina at Chapel Hill, Chapel Hill, NC, USA
| | - Michael A Gray
- Institute for Cell and Molecular Biosciences, Newcastle University, Newcastle upon Tyne, NE2 4HH, UK.
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Vecchio EA, White PJ, May LT. The adenosine A 2B G protein-coupled receptor: Recent advances and therapeutic implications. Pharmacol Ther 2019; 198:20-33. [PMID: 30677476 DOI: 10.1016/j.pharmthera.2019.01.003] [Citation(s) in RCA: 30] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/13/2022]
Abstract
The adenosine A2B receptor (A2BAR) is one of four adenosine receptor subtypes belonging to the Class A family of G protein-coupled receptors (GPCRs). Until recently, the A2BAR remained poorly characterised, in part due to its relatively low affinity for the endogenous agonist adenosine and therefore presumed minor physiological significance. However, the substantial increase in extracellular adenosine concentration, the sensitisation of the receptor and the upregulation of A2BAR expression under conditions of hypoxia and inflammation, suggest the A2BAR as an exciting therapeutic target in a variety of pathological disease states. Here we discuss the pharmacology of the A2BAR and outline its role in pathophysiology including ischaemia-reperfusion injury, fibrosis, inflammation and cancer.
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Affiliation(s)
- Elizabeth A Vecchio
- Drug Discovery Biology, Monash Institute of Pharmaceutical Sciences, Monash University, Parkville, VIC 3052, Australia; Heart Failure Pharmacology, Baker Heart & Diabetes Institute, Melbourne, VIC 3004, Australia
| | - Paul J White
- Drug Discovery Biology, Monash Institute of Pharmaceutical Sciences, Monash University, Parkville, VIC 3052, Australia
| | - Lauren T May
- Drug Discovery Biology, Monash Institute of Pharmaceutical Sciences, Monash University, Parkville, VIC 3052, Australia.
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Beach KM, Hung LF, Arumugam B, Smith EL, Ostrin LA. Adenosine receptor distribution in Rhesus monkey ocular tissue. Exp Eye Res 2018; 174:40-50. [PMID: 29792846 DOI: 10.1016/j.exer.2018.05.020] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/06/2018] [Revised: 04/26/2018] [Accepted: 05/20/2018] [Indexed: 02/06/2023]
Abstract
Adenosine receptor (ADOR) antagonists, such as 7-methylxanthine (7-MX), have been shown to slow myopia progression in humans and animal models. Adenosine receptors are found throughout the body, and regulate the release of neurotransmitters such as dopamine and glutamate. However, the role of adenosine in eye growth is unclear. Evidence suggests that 7-MX increases scleral collagen fibril diameter, hence preventing axial elongation. This study used immunohistochemistry (IHC) and reverse-transcription quantitative polymerase chain reaction (RT-qPCR) to examine the distribution of the four ADORs in the normal monkey eye to help elucidate potential mechanisms of action. Eyes were enucleated from six Rhesus monkeys. Anterior segments and eyecups were separated into components and flash-frozen for RNA extraction or fixed in 4% paraformaldehyde and processed for immunohistochemistry against ADORA1, ADORA2a, ADORA2b, and ADORA3. RNA was reverse-transcribed, and qPCR was performed using custom primers. Relative gene expression was calculated using the ΔΔCt method normalizing to liver expression, and statistical analysis was performed using Relative Expression Software Tool. ADORA1 immunostaining was highest in the iris sphincter muscle, trabecular meshwork, ciliary epithelium, and retinal nerve fiber layer. ADORA2a immunostaining was highest in the corneal epithelium, trabecular meshwork, ciliary epithelium, retinal nerve fiber layer, and scleral fibroblasts. ADORA2b immunostaining was highest in corneal basal epithelium, limbal stem cells, iris sphincter, ciliary muscle, ciliary epithelium, choroid, isolated retinal ganglion cells and scattered scleral fibroblasts. ADORA3 immunostaining was highest in the iris sphincter, ciliary muscle, ciliary epithelium, choroid, isolated retinal ganglion cells, and scleral fibroblasts. Compared to liver mRNA, ADORA1 mRNA was significantly higher in the brain, retina and choroid, and significantly lower in the iris/ciliary body. ADORA2a expression was higher in brain and retina, ADORA2b expression was higher in retina, and ADORA3 was higher in the choroid. In conclusion, immunohistochemistry and RT-qPCR indicated differential patterns of expression of the four adenosine receptors in the ocular tissues of the normal non-human primate. The presence of ADORs in scleral fibroblasts and the choroid may support mechanisms by which ADOR antagonists prevent myopia. The potential effects of ADOR inhibition on both anterior and posterior ocular structures warrant investigation.
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Affiliation(s)
- Krista M Beach
- University of Houston College of Optometry, 4901 Calhoun Rd, Houston, TX 77204, USA
| | - Li-Fang Hung
- University of Houston College of Optometry, 4901 Calhoun Rd, Houston, TX 77204, USA
| | - Baskar Arumugam
- University of Houston College of Optometry, 4901 Calhoun Rd, Houston, TX 77204, USA
| | - Earl L Smith
- University of Houston College of Optometry, 4901 Calhoun Rd, Houston, TX 77204, USA
| | - Lisa A Ostrin
- University of Houston College of Optometry, 4901 Calhoun Rd, Houston, TX 77204, USA.
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Bessa-Gonçalves M, Bragança B, Martins-Dias E, Correia-de-Sá P, Fontes-Sousa AP. Is the adenosine A 2B 'biased' receptor a valuable target for the treatment of pulmonary arterial hypertension? Drug Discov Today 2018; 23:1285-1292. [PMID: 29747005 DOI: 10.1016/j.drudis.2018.05.005] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/19/2018] [Revised: 03/25/2018] [Accepted: 05/02/2018] [Indexed: 12/12/2022]
Abstract
Pulmonary arterial hypertension (PAH) is a maladaptive disorder characterized by increased pulmonary vascular resistance leading to right ventricular failure and death. Adenosine released by injured tissues, such as the lung and heart, influences tissue remodeling through the activation of adenosine receptors. Evidence regarding activation of the low-affinity A2BAR by adenosine points towards pivotal roles of this receptor in processes associated with both acute and chronic lung diseases. Conflicting results exist concerning the beneficial or detrimental roles of the A2B 'biased' receptor in right ventricular failure secondary to PAH. In this review, we discuss the pros and cons of manipulating A2BARs as a putative therapeutic target in PAH.
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Affiliation(s)
- Mafalda Bessa-Gonçalves
- Laboratório de Farmacologia e Neurobiologia, Centro de Investigação Farmacológica e Inovação Medicamentosa (MedInUP), Instituto de Ciências Biomédicas Abel Salazar, Universidade do Porto (ICBAS-UP), Porto, Portugal
| | - Bruno Bragança
- Laboratório de Farmacologia e Neurobiologia, Centro de Investigação Farmacológica e Inovação Medicamentosa (MedInUP), Instituto de Ciências Biomédicas Abel Salazar, Universidade do Porto (ICBAS-UP), Porto, Portugal
| | - Eduardo Martins-Dias
- Laboratório de Farmacologia e Neurobiologia, Centro de Investigação Farmacológica e Inovação Medicamentosa (MedInUP), Instituto de Ciências Biomédicas Abel Salazar, Universidade do Porto (ICBAS-UP), Porto, Portugal
| | - Paulo Correia-de-Sá
- Laboratório de Farmacologia e Neurobiologia, Centro de Investigação Farmacológica e Inovação Medicamentosa (MedInUP), Instituto de Ciências Biomédicas Abel Salazar, Universidade do Porto (ICBAS-UP), Porto, Portugal
| | - Ana Patrícia Fontes-Sousa
- Laboratório de Farmacologia e Neurobiologia, Centro de Investigação Farmacológica e Inovação Medicamentosa (MedInUP), Instituto de Ciências Biomédicas Abel Salazar, Universidade do Porto (ICBAS-UP), Porto, Portugal.
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14
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Gao ZG, Inoue A, Jacobson KA. On the G protein-coupling selectivity of the native A 2B adenosine receptor. Biochem Pharmacol 2018; 151:201-213. [PMID: 29225130 PMCID: PMC5899946 DOI: 10.1016/j.bcp.2017.12.003] [Citation(s) in RCA: 25] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/25/2017] [Accepted: 12/05/2017] [Indexed: 12/14/2022]
Abstract
A2B adenosine receptor (A2BAR) activation induces Gs-dependent cyclic AMP accumulation. However, A2BAR G protein-coupling to other signaling events, e.g. ERK1/2 and calcium, is not well documented. We explored Gi, Gq/11 and Gs coupling in 1321 N1 astrocytoma, HEK293, and T24 bladder cancer cells endogenously expressing human A2BAR, using NECA or nonnucleoside BAY60-6583 as agonist, selective Gi, Gs and Gq/11 blockers, and CRISPR/Cas9-based Gq- and Gs-null HEK293 cells. In HEK293 cells, A2BAR-mediated ERK1/2 activity occurred via both Gi and Gs, but not Gq/11. However, HEK293 cell calcium mobilization was completely blocked by Gq/11 inhibitor UBO-QIC and by Gq/11 knockout. In T24 cells, Gi was solely responsible for A2BAR-mediated ERK1/2 stimulation, and Gs suppressed ERK1/2 activity. A2BAR-mediated intracellular calcium mobilization in T24 cells was mainly via Gi, although Gs may also play a role, but Gq/11 is not involved. In 1321 N1 astrocytoma cells A2BAR activation suppressed rather than stimulated ERK1/2 activity. The ERK1/2 activity decrease was reversed by Gs downregulation using cholera toxin, but potentiated by Gi inhibitor pertussis toxin, and UBO-QIC had no effect. EPACs played an important role in A2BAR-mediated ERK1/2 signaling in all three cells. Thus, A2BAR may: couple to the same downstream pathway via different G proteins in different cell types; activate different downstream events via different G proteins in the same cell type; activate Gi and Gs, which have opposing or synergistic roles in different cell types/signaling pathways. The findings, relevant to drug discovery, address some reported controversial roles of A2BAR and could apply to signaling mechanisms in other GPCRs.
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Affiliation(s)
- Zhan-Guo Gao
- Molecular Recognition Section, Laboratory of Bioorganic Chemistry, NIDDK, National Institutes of Health, 9000 Rockville Pike, Bethesda, MD 20892, USA.
| | - Asuka Inoue
- Graduate School of Pharmaceutical Sciences, Tohoku University, Sendai, Miyagi 980-8578, Japan
| | - Kenneth A Jacobson
- Molecular Recognition Section, Laboratory of Bioorganic Chemistry, NIDDK, National Institutes of Health, 9000 Rockville Pike, Bethesda, MD 20892, USA.
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15
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The Adenosinergic System as a Therapeutic Target in the Vasculature: New Ligands and Challenges. Molecules 2017; 22:molecules22050752. [PMID: 28481238 PMCID: PMC6154114 DOI: 10.3390/molecules22050752] [Citation(s) in RCA: 20] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/17/2017] [Revised: 04/24/2017] [Accepted: 05/02/2017] [Indexed: 12/20/2022] Open
Abstract
Adenosine is an adenine base purine with actions as a modulator of neurotransmission, smooth muscle contraction, and immune response in several systems of the human body, including the cardiovascular system. In the vasculature, four P1-receptors or adenosine receptors—A1, A2A, A2B and A3—have been identified. Adenosine receptors are membrane G-protein receptors that trigger their actions through several signaling pathways and present differential affinity requirements. Adenosine is an endogenous ligand whose extracellular levels can reach concentrations high enough to activate the adenosine receptors. This nucleoside is a product of enzymatic breakdown of extra and intracellular adenine nucleotides and also of S-adenosylhomocysteine. Adenosine availability is also dependent on the activity of nucleoside transporters (NTs). The interplay between NTs and adenosine receptors’ activities are debated and a particular attention is given to the paramount importance of the disruption of this interplay in vascular pathophysiology, namely in hypertension., The integration of important functional aspects of individual adenosine receptor pharmacology (such as in vasoconstriction/vasodilation) and morphological features (within the three vascular layers) in vessels will be discussed, hopefully clarifying the importance of adenosine receptors/NTs for modulating peripheral mesenteric vascular resistance. In recent years, an increase interest in purine physiology/pharmacology has led to the development of new ligands for adenosine receptors. Some of them have been patented as having promising therapeutic activities and some have been chosen to undergo on clinical trials. Increased levels of endogenous adenosine near a specific subtype can lead to its activation, constituting an indirect receptor targeting approach either by inhibition of NT or, alternatively, by increasing the activity of enzymes responsible for ATP breakdown. These findings highlight the putative role of adenosinergic players as attractive therapeutic targets for cardiovascular pathologies, namely hypertension, heart failure or stroke. Nevertheless, several aspects are still to be explored, creating new challenges to be addressed in future studies, particularly the development of strategies able to circumvent the predicted side effects of these therapies.
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Sun Y, Huang P. Adenosine A2B Receptor: From Cell Biology to Human Diseases. Front Chem 2016; 4:37. [PMID: 27606311 PMCID: PMC4995213 DOI: 10.3389/fchem.2016.00037] [Citation(s) in RCA: 49] [Impact Index Per Article: 6.1] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/23/2016] [Accepted: 08/11/2016] [Indexed: 12/26/2022] Open
Abstract
Extracellular adenosine is a ubiquitous signaling molecule that modulates a wide array of biological processes. Recently, significant advances have been made in our understanding of A2B adenosine receptor (A2BAR). In this review, we first summarize some of the general characteristics of A2BAR, and then we describe the multiple binding partners of the receptor, such as newly identified α-actinin-1 and p105, and discuss how these associated proteins could modulate A2BAR's functions, including certain seemingly paradoxical functions of the receptor. Growing evidence indicates a critical role of A2BAR in cancer, renal disease, and diabetes, in addition to its importance in the regulation of vascular diseases, and lung disease. Here, we also discuss the role of A2BAR in cancer, renal disease, and diabetes and the potential of the receptor as a target for treating these three diseases.
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Affiliation(s)
- Ying Sun
- Department of Biology, South University of Science and Technology of ChinaShenzhen, China; Shenzhen Key Laboratory of Cell Microenvironment, South University of Science and Technology of ChinaShenzhen, China
| | - Pingbo Huang
- Division of Life Science, Hong Kong University of Science and TechnologyHong Kong, China; Division of Biomedical Engineering, Hong Kong University of Science and TechnologyHong Kong, China; State Key Laboratory of Molecular Neuroscience, Hong Kong University of Science and TechnologyHong Kong, China
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17
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Zhai W, Chen D, Shen H, Chen Z, Li H, Yu Z, Chen G. A1 adenosine receptor attenuates intracerebral hemorrhage-induced secondary brain injury in rats by activating the P38-MAPKAP2-Hsp27 pathway. Mol Brain 2016; 9:66. [PMID: 27301321 PMCID: PMC4908780 DOI: 10.1186/s13041-016-0247-x] [Citation(s) in RCA: 24] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/14/2016] [Accepted: 06/02/2016] [Indexed: 12/27/2022] Open
Abstract
Background This study was designed to determine the role of the A1 adenosine receptors in intracerebral hemorrhage (ICH)-induced secondary brain injury and the underlying mechanisms. Methods A collagenase-induced ICH model was established in Sprague–Dawley rats, and cultured primary rat cortical neurons were exposed to oxyhemoglobin at a concentration of 10 μM to mimic ICH in vitro. The A1 adenosine receptor agonist N(6)-cyclohexyladenosine and antagonist 8-phenyl-1,3-dipropylxanthine were used to study the role of A1 adenosine receptor in ICH-induced secondary brain injury, and antagonists of P38 and Hsp27 were used to study the underlying mechanisms of A1 adenosine receptor actions. Results The protein level of A1 adenosine receptor was significantly increased by ICH, while there was no significant change in protein levels of the other 3 adenosine receptors. In addition, the A1 adenosine receptor expression could be increased by N(6)-cyclohexyladenosine and decreased by 8-phenyl-1,3-dipropylxanthine under ICH conditions. Activation of the A1 adenosine receptor attenuated neuronal apoptosis in the subcortex, which was associated with increased phosphorylation of P38, MAPK, MAPKAP2, and Hsp27. Inhibition of the A1 adenosine receptor resulted in opposite effects. Finally, the neuroprotective effect of the A1 adenosine receptor agonist N(6)-cyclohexyladenosine was inhibited by antagonists of P38 and Hsp27. Conclusions This study demonstrates that activation of the A1 adenosine receptor by N(6)-cyclohexyladenosine could prevent ICH-induced secondary brain injury via the P38-MAPKAP2-Hsp27 pathway.
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Affiliation(s)
- Weiwei Zhai
- Department of Neurosurgery & Brain and Nerve Research Laboratory, The First Affiliated Hospital of Soochow University, 188 Shizi Street, Suzhou, 215006, China
| | - Dongdong Chen
- Department of Neurosurgery & Brain and Nerve Research Laboratory, The First Affiliated Hospital of Soochow University, 188 Shizi Street, Suzhou, 215006, China
| | - Haitao Shen
- Department of Neurosurgery & Brain and Nerve Research Laboratory, The First Affiliated Hospital of Soochow University, 188 Shizi Street, Suzhou, 215006, China
| | - Zhouqing Chen
- Department of Neurosurgery & Brain and Nerve Research Laboratory, The First Affiliated Hospital of Soochow University, 188 Shizi Street, Suzhou, 215006, China
| | - Haiying Li
- Department of Neurosurgery & Brain and Nerve Research Laboratory, The First Affiliated Hospital of Soochow University, 188 Shizi Street, Suzhou, 215006, China
| | - Zhengquan Yu
- Department of Neurosurgery & Brain and Nerve Research Laboratory, The First Affiliated Hospital of Soochow University, 188 Shizi Street, Suzhou, 215006, China.
| | - Gang Chen
- Department of Neurosurgery & Brain and Nerve Research Laboratory, The First Affiliated Hospital of Soochow University, 188 Shizi Street, Suzhou, 215006, China.
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18
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Yang Z, Tao YX. Biased signaling initiated by agouti-related peptide through human melanocortin-3 and -4 receptors. Biochim Biophys Acta Mol Basis Dis 2016; 1862:1485-94. [PMID: 27208795 DOI: 10.1016/j.bbadis.2016.05.008] [Citation(s) in RCA: 33] [Impact Index Per Article: 4.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/02/2016] [Revised: 05/09/2016] [Accepted: 05/16/2016] [Indexed: 01/01/2023]
Abstract
The neural melanocortin receptors (MCRs), melanocortin-3 and -4 receptors (MC3R and MC4R), have been increasingly recognized as important regulators of energy homeostasis. The orexigenic agouti-related peptide (AgRP), initially identified as an endogenous antagonist for both neural MCRs, has been suggested to be a biased agonist of MC4R independent of its antagonizing effects. In the present study, we sought to determine the potential of AgRP to regulate the activation of intracellular kinases, including extracellular signal-regulated kinase 1 and 2 (ERK1/2), AKT and AMP-activated protein kinase (AMPK), through neural MCRs. We showed that AgRP acted as a biased agonist in human MC3R (hMC3R), decreasing cAMP activity of constitutively active mutant (F347A) hMC3R but stimulating ERK1/2 activation in both wide type and F347A hMC3Rs. AgRP-stimulated ERK1/2 phosphorylation through MC3R was abolished by protein kinase A (PKA) inhibitor H-89 but not Rp-cAMPS, whereas AgRP-initiated ERK1/2 activation through MC4R was inhibited by phosphatidylinositol 3-kinase (PI3K) inhibitors wortmannin and LY294002. Both NDP-MSH and AgRP treatment induced significant AKT phosphorylation in GT1-7 cells but not in MC3R- or MC4R-transfected HEK293T cells. The phosphorylated AMPK levels in both GT1-7 cells and HERK293T cells transfected with neural MCRs were significantly decreased upon stimulation with NDP-MSH but not with AgRP. In summary, we provided novel data for AgRP-initiated multiple intracellular signaling pathways, demonstrating biased agonism of AgRP in both neural MCRs, leading to a better understanding of neural MCR pharmacology.
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MESH Headings
- AMP-Activated Protein Kinases/metabolism
- Agouti-Related Protein/metabolism
- Amino Acid Substitution
- Central Nervous System/metabolism
- Cyclic AMP/metabolism
- HEK293 Cells
- Humans
- Kinetics
- Ligands
- MAP Kinase Signaling System
- Mutagenesis, Site-Directed
- Peptide Fragments/metabolism
- Proto-Oncogene Proteins c-akt/metabolism
- Receptor, Melanocortin, Type 3/agonists
- Receptor, Melanocortin, Type 3/genetics
- Receptor, Melanocortin, Type 3/metabolism
- Receptor, Melanocortin, Type 4/agonists
- Receptor, Melanocortin, Type 4/genetics
- Receptor, Melanocortin, Type 4/metabolism
- Recombinant Proteins/genetics
- Recombinant Proteins/metabolism
- Signal Transduction
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Affiliation(s)
- Zhao Yang
- Department of Anatomy, Physiology and Pharmacology, College of Veterinary Medicine, Auburn University, Auburn, AL 36849, United States
| | - Ya-Xiong Tao
- Department of Anatomy, Physiology and Pharmacology, College of Veterinary Medicine, Auburn University, Auburn, AL 36849, United States.
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Ribeiro FF, Neves-Tomé R, Assaife-Lopes N, Santos TE, Silva RFM, Brites D, Ribeiro JA, Sousa MM, Sebastião AM. Axonal elongation and dendritic branching is enhanced by adenosine A2A receptors activation in cerebral cortical neurons. Brain Struct Funct 2015; 221:2777-99. [DOI: 10.1007/s00429-015-1072-1] [Citation(s) in RCA: 29] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/07/2015] [Accepted: 05/27/2015] [Indexed: 01/09/2023]
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20
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Dos Santos-Rodrigues A, Pereira MR, Brito R, de Oliveira NA, Paes-de-Carvalho R. Adenosine transporters and receptors: key elements for retinal function and neuroprotection. VITAMINS AND HORMONES 2015; 98:487-523. [PMID: 25817878 DOI: 10.1016/bs.vh.2014.12.014] [Citation(s) in RCA: 24] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/13/2022]
Abstract
Adenosine is an important neuroactive substance in the central nervous system, including in the retina where subclasses of adenosine receptors and transporters are expressed since early stages of development. Here, we review some evidence showing that adenosine plays important functions in the mature as well as in the developing tissue. Adenosine transporters are divided into equilibrative and concentrative, and the major transporter subtype present in the retina is the ENT1. This transporter is responsible for a bidirectional transport of adenosine and the uptake or release of this nucleoside appears to be regulated by different signaling pathways that are also controlled by activation of adenosine receptors. Adenosine receptors are also key players in retina physiology regulating a variety of functions in the mature and developing tissue. Regulation of excitatory neurotransmitter release and neuroprotection are the main functions played be adenosine in the mature tissue, while regulation of cell survival and neurogenesis are some of the functions played by adenosine in developing retina. Since adenosine is neuroprotective against excitotoxic and metabolic dysfunctions observed in neurological and ocular diseases, the search for adenosine-related drugs regulating adenosine transporters and receptors can be important for advancement of therapeutic strategies against these diseases.
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Affiliation(s)
| | - Mariana R Pereira
- Program of Neurosciences, Fluminense Federal University, Niterói, Rio de Janeiro, Brazil
| | - Rafael Brito
- Program of Neurosciences, Fluminense Federal University, Niterói, Rio de Janeiro, Brazil
| | - Nádia A de Oliveira
- Program of Neurosciences, Fluminense Federal University, Niterói, Rio de Janeiro, Brazil
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21
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Activation of adenosine A2B receptor impairs properties of trophoblast cells and involves mitogen-activated protein (MAP) kinase signaling. Placenta 2014; 35:763-71. [DOI: 10.1016/j.placenta.2014.06.369] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 11/13/2013] [Revised: 06/16/2014] [Accepted: 06/17/2014] [Indexed: 11/23/2022]
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22
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Formosa R, Vassallo J. cAMP signalling in the normal and tumorigenic pituitary gland. Mol Cell Endocrinol 2014; 392:37-50. [PMID: 24845420 DOI: 10.1016/j.mce.2014.05.004] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 02/17/2014] [Revised: 05/04/2014] [Accepted: 05/05/2014] [Indexed: 01/06/2023]
Abstract
cAMP signalling plays a key role in the normal physiology of the pituitary gland, regulating cellular growth and proliferation, hormone production and release. Deregulation of the cAMP signalling pathway has been reported to be a common occurrence in pituitary tumorigenesis. Several mechanisms have been implicated including somatic mutations, gene-gene interactions and gene-environmental interactions. Somatic mutations in G-proteins and protein kinases directly alter cAMP signalling, while malfunctioning of other signalling pathways such as the Raf/MAPK/ERK, PI3K/Akt/mTOR and Wnt pathways which normally interact with the cAMP pathway may mediate indirect effects on cAMP and varying downstream effectors. The aryl hydrocarbon receptor signalling pathway has been implicated in pituitary tumorigenesis and we review its role in general and specifically in relation to cAMP de-regulation.
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Affiliation(s)
- R Formosa
- Department of Medicine, Faculty of Medicine and Surgery, University of Malta, Level 0, Block A, Mater Dei Hospital, Msida MSD2080, Malta.
| | - J Vassallo
- Department of Medicine, Faculty of Medicine and Surgery, University of Malta, Level 0, Block A, Mater Dei Hospital, Msida MSD2080, Malta.
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23
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Hinz S, Lacher SK, Seibt BF, Müller CE. BAY60-6583 acts as a partial agonist at adenosine A2B receptors. J Pharmacol Exp Ther 2014; 349:427-36. [PMID: 24633424 DOI: 10.1124/jpet.113.210849] [Citation(s) in RCA: 47] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/01/2023] Open
Abstract
BAY60-6583 [2-({6-amino-3,5-dicyano-4-[4-(cyclopropylmethoxy)phenyl]pyridin-2-yl}sulfanyl)acetamide] is the most potent and selective adenosine A2B receptor (A2B AR) agonist known to date. Therefore, it has been widely used for in vitro and in vivo experiments. In the present study, we investigated the binding and functional properties of BAY60-6583 in various native and recombinant cell lines with different A2B AR expression levels. In cAMP accumulation and calcium mobilization assays, BAY60-6583 was found to be significantly less efficacious than adenosine or the adenosine derivative NECA. When it was tested in human embryonic kidney (HEK)293 cells, its efficacy correlated with the A2B expression level of the cells. In Jurkat T cells, BAY60-6583 antagonized the agonistic effect of NECA and adenosine as determined in cAMP accumulation assays. On the basis of these results, we conclude that BAY60-6583 acts as a partial agonist at adenosine A2B receptors. At high levels of the physiologic agonist adenosine, BAY60-6583 may act as an antagonist and block the effects of adenosine at A2B receptors. This has to be considered when applying the A2B-selective "agonist" BAY60-6583 in pharmacological studies, and previous research results may have to be reinterpreted.
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Affiliation(s)
- Sonja Hinz
- PharmaCenter Bonn, Pharmaceutical Institute, Pharmaceutical Chemistry I, University of Bonn, Bonn, Germany
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24
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Michel G, Matthes HWD, Hachet-Haas M, El Baghdadi K, de Mey J, Pepperkok R, Simpson JC, Galzi JL, Lecat S. Plasma membrane translocation of REDD1 governed by GPCRs contributes to mTORC1 activation. J Cell Sci 2013; 127:773-87. [PMID: 24338366 DOI: 10.1242/jcs.136432] [Citation(s) in RCA: 24] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/19/2022] Open
Abstract
The mTORC1 kinase promotes cell growth in response to growth factors by activation of receptor tyrosine kinase. It is regulated by the cellular energy level and the availability of nutrients. mTORC1 activity is also inhibited by cellular stresses through overexpression of REDD1 (regulated in development and DNA damage responses). We report the identification of REDD1 in a fluorescent live-imaging screen aimed at discovering new proteins implicated in G-protein-coupled receptor signaling, based on translocation criteria. Using a sensitive and quantitative plasma membrane localization assay based on bioluminescent resonance energy transfer, we further show that a panel of endogenously expressed GPCRs, through a Ca(2+)/calmodulin pathway, triggers plasma membrane translocation of REDD1 but not of its homolog REDD2. REDD1 and REDD2 share a conserved mTORC1-inhibitory motif characterized at the functional and structural level and differ most in their N-termini. We show that the N-terminus of REDD1 and its mTORC1-inhibitory motif participate in the GPCR-evoked dynamic interaction of REDD1 with the plasma membrane. We further identify REDD1 as a novel effector in GPCR signaling. We show that fast activation of mTORC1 by GPCRs correlates with fast and maximal translocation of REDD1 to the plasma membrane. Overexpression of functional REDD1 leads to a reduction of mTORC1 activation by GPCRs. By contrast, depletion of endogenous REDD1 protein unleashes mTORC1 activity. Thus, translocation to the plasma membrane appears to be an inactivation mechanism of REDD1 by GPCRs, which probably act by sequestering its functional mTORC1-inhibitory motif that is necessary for plasma membrane targeting.
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Affiliation(s)
- Grégory Michel
- GPCRs, Pain and Inflammation Team, UMR7242, CNRS-University of Strasbourg, LabEx Medalis, 67412 Illkirch, France
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25
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Jacobson KA, Balasubramanian R, Deflorian F, Gao ZG. G protein-coupled adenosine (P1) and P2Y receptors: ligand design and receptor interactions. Purinergic Signal 2012; 8:419-36. [PMID: 22371149 PMCID: PMC3360101 DOI: 10.1007/s11302-012-9294-7] [Citation(s) in RCA: 67] [Impact Index Per Article: 5.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/08/2011] [Accepted: 01/30/2012] [Indexed: 12/17/2022] Open
Abstract
The medicinal chemistry and pharmacology of the four subtypes of adenosine receptors (ARs) and the eight subtypes of P2Y receptors (P2YRs, activated by a range of purine and pyrimidine mono- and dinucleotides) has recently advanced significantly leading to selective ligands. X-ray crystallographic structures of both agonist- and antagonist-bound forms of the A(2A)AR have provided unprecedented three-dimensional detail concerning molecular recognition in the binding site and the conformational changes in receptor activation. It is apparent that this ubiquitous cell signaling system has implications for understanding and treating many diseases. ATP and other nucleotides are readily released from intracellular sources under conditions of injury and organ stress, such as hypoxia, ischemia, or mechanical stress, and through channels and vesicular release. Adenosine may be generated extracellularly or by cellular release. Therefore, depending on pathophysiological factors, in a given tissue, there is often a tonic activation of one or more of the ARs or P2YRs that can be modulated by exogenous agents for a beneficial effect. Thus, this field has provided fertile ground for pharmaceutical development, leading to clinical trials of selective receptor ligands as imaging agents or for conditions including cardiac arrhythmias, ischemia/reperfusion injury, diabetes, pain, thrombosis, Parkinson's disease, rheumatoid arthritis, psoriasis, dry eye disease, pulmonary diseases such as cystic fibrosis, glaucoma, cancer, chronic hepatitis C, and other diseases.
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Affiliation(s)
- Kenneth A Jacobson
- 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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Du L, Gao ZG, Nithipatikom K, Ijzerman AP, Veldhoven JPDV, Jacobson KA, Gross GJ, Auchampach JA. Protection from myocardial ischemia/reperfusion injury by a positive allosteric modulator of the A₃ adenosine receptor. J Pharmacol Exp Ther 2011; 340:210-7. [PMID: 22011434 DOI: 10.1124/jpet.111.187559] [Citation(s) in RCA: 24] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/10/2023] Open
Abstract
Adenosine is increased in ischemic tissues where it serves a protective role by activating adenosine receptors (ARs), including the A₃ AR subtype. We investigated the effect of N-{2-[(3,4-dichlorophenyl)amino]quinolin-4-yl}cyclohexanecarboxamide (LUF6096), a positive allosteric modulator of the A₃ AR, on infarct size in a barbital-anesthetized dog model of myocardial ischemia/reperfusion injury. Dogs were subjected to 60 min of coronary artery occlusion and 3 h of reperfusion. Infarct size was assessed by macrohistochemical staining. Three experimental groups were included in the study. Groups I and II received two doses of vehicle or LUF6096 (0.5 mg/kg i.v. bolus), one administered before ischemia and the other immediately before reperfusion. Group III received a single dose of LUF6096 (1 mg/kg i.v. bolus) immediately before reperfusion. In preliminary in vitro studies, LUF6096 was found to exert potent enhancing activity (EC₅₀ 114.3 ± 15.9 nM) with the canine A₃ AR in a guanosine 5'-[γ-[³⁵S]thio]triphosphate binding assay. LUF6096 increased the maximal efficacy of the partial A₃ AR agonist 2-chloro-N⁶-(3-iodobenzyl)adenosine-5'-N-methylcarboxamide and the native agonist adenosine more than 2-fold while producing a slight decrease in potency. In the dog studies, administration of LUF6096 had no effect on any hemodynamic parameter measured. Pretreatment with LUF6096 before coronary occlusion and during reperfusion in group II dogs produced a marked reduction in infarct size (∼50% reduction) compared with group I vehicle-treated dogs. An equivalent reduction in infarct size was observed when LUF6096 was administered immediately before reperfusion in group III dogs. This is the first study to demonstrate efficacy of an A₃ AR allosteric enhancer in an in vivo model of infarction.
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Affiliation(s)
- Lili Du
- Department of Pharmacology and the Cardiovascular Center, Medical College of Wisconsin, Milwaukee, Wisconsin, USA
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Cai M, Huttinger ZM, He H, Zhang W, Li F, Goodman LA, Wheeler DG, Druhan LJ, Zweier JL, Dwyer KM, He G, d'Apice AJF, Robson SC, Cowan PJ, Gumina RJ. Transgenic over expression of ectonucleotide triphosphate diphosphohydrolase-1 protects against murine myocardial ischemic injury. J Mol Cell Cardiol 2011; 51:927-35. [PMID: 21939667 DOI: 10.1016/j.yjmcc.2011.09.003] [Citation(s) in RCA: 38] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 05/23/2011] [Revised: 08/23/2011] [Accepted: 09/03/2011] [Indexed: 02/06/2023]
Abstract
Modulation of purinergic signaling is critical to myocardial homeostasis. Ectonucleoside triphosphate diphosphohydrolase 1 (ENTPD-1; CD39) which converts the proinflammatory molecules ATP or ADP to AMP is a key regulator of purinergic modulation. However, the salutary effects of transgenic over expression of ENTPD-1 on myocardial response to ischemic injury have not been tested to date. Therefore we hypothesized that ENTPD-1 over expression affords myocardial protection from ischemia-reperfusion injury via specific cell signaling pathways. ENTPD-1 transgenic mice, which over express human ENTPDase-1, and wild-type (WT) littermates were subjected to either ex vivo or in vivo ischemia-reperfusion injury. Infarct size, inflammatory cell infiltrate and intracellular signaling molecule activation were evaluated. Infarct size was significantly reduced in ENTPD-1 versus WT hearts in both ex vivo and in vivo studies. Following ischemia-reperfusion injury, ENTPD-1 cardiac tissues demonstrated an increase in the phosphorylation of the cellular signaling molecule extracellular signal-regulated kinases 1/2 (ERK 1/2) and glycogen synthase kinase-3β (GSK-3β). Resistance to myocardial injury was abrogated by treatment with a non-selective adenosine receptor antagonist, 8-SPT or the more selective A(2B) adenosine receptor antagonist, MRS 1754, but not the A(1) selective antagonists, DPCPX. Additionally, treatment with the ERK 1/2 inhibitor PD98059 or the mitochondrial permeability transition pore opener, atractyloside, abrogated the cardiac protection provided by ENTPDase-1 expression. These results suggest that transgenic ENTPDase-1 expression preferentially conveys myocardial protection from ischemic injury via adenosine A(2B) receptor engagement and associated phosphorylation of the cellular protective signaling molecules, Akt, ERK 1/2 and GSK-3β that prevents detrimental opening of the mitochondrial permeability transition pore.
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Affiliation(s)
- Ming Cai
- Division of Cardiovascular Medicine and Davis Heart and Lung Research Institute, The Ohio State University, Columbus, OH, USA
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Yang X, Xin W, Yang XM, Kuno A, Rich TC, Cohen MV, Downey JM. A2B adenosine receptors inhibit superoxide production from mitochondrial complex I in rabbit cardiomyocytes via a mechanism sensitive to Pertussis toxin. Br J Pharmacol 2011; 163:995-1006. [PMID: 21366548 PMCID: PMC3130946 DOI: 10.1111/j.1476-5381.2011.01288.x] [Citation(s) in RCA: 32] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/20/2009] [Revised: 01/04/2011] [Accepted: 01/22/2011] [Indexed: 11/28/2022] Open
Abstract
BACKGROUND AND PURPOSE A(2B) adenosine receptors protect against ischaemia/reperfusion injury by activating survival kinases including extracellular signal-regulated kinase (ERK) and phosphatidylinositol 3-kinase (PI3K). However, the underlying mechanism(s) and signalling pathway(s) remain undefined. EXPERIMENTAL APPROACH HEK 293 cells stably transfected with human A(2B) adenosine receptors (HEK-A(2B) ) and isolated adult rabbit cardiomyocytes were used to assay phosphorylation of ERK by Western blot and cation flux through cAMP-gated channels by patch clamp methods. Generation of reactive oxygen species (ROS) by mitochondria was measured with a fluorescent dye. KEY RESULTS In HEK-A(2B) cells, the selective A(2B) receptor agonist Bay 60-6583 (Bay 60) increased ERK phosphorylation and cAMP levels, detected by current through cAMP-gated ion channels. However, increased cAMP or its downstream target protein kinase A was not involved in ERK phosphorylation. Pertussis toxin (PTX) blocked ERK phosphorylation, suggesting receptor coupling to G(i) or G(o) proteins. Phosphorylation was also blocked by inhibition of PI3K (with wortmannin) or of ERK kinase (MEK1/2, with PD 98059) but not by inhibition of NO synthase (NOS). In cardiomyocytes, Bay 60 did not affect cAMP levels but did block the increased superoxide generation induced by rotenone, a mitochondrial complex I inhibitor. This effect of Bay 60 was inhibited by PD 98059, wortmannin or PTX. Inhibition of NOS blocked superoxide production because NOS is downstream of ERK. CONCLUSION AND IMPLICATIONS Activation of A(2B) adenosine receptors reduced superoxide generation from mitochondrial complex I through G(i/o) , ERK, PI3K, and NOS, all of which have been implicated in ischaemic preconditioning.
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Affiliation(s)
- Xiulan Yang
- Department of Physiology Pharmacology Medicine, University of South Alabama, College of Medicine, Mobile, AL 36688, USA
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29
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van der Hoeven D, Wan TC, Gizewski ET, Kreckler LM, Maas JE, Van Orman J, Ravid K, Auchampach JA. A role for the low-affinity A2B adenosine receptor in regulating superoxide generation by murine neutrophils. J Pharmacol Exp Ther 2011; 338:1004-12. [PMID: 21693629 DOI: 10.1124/jpet.111.181792] [Citation(s) in RCA: 44] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/27/2022] Open
Abstract
The formation of adenosine dampens inflammation by inhibiting most cells of the immune system. Among its actions on neutrophils, adenosine suppresses superoxide generation and regulates chemotactic activity. To date, most evidence implicates the G(s) protein-coupled A(2A) adenosine receptor (AR) as the primary AR subtype responsible for mediating the actions of adenosine on neutrophils by stimulating cAMP production. Given that the A(2B)AR is now known to be expressed in neutrophils and that it is a G(s) protein-coupled receptor, we examined in this study whether it signals to suppress neutrophil activities by using 2-[6-amino-3,5-dicyano-4-[4-(cyclopropylmethoxy)phenyl]pyridin-2-ylsulfanyl]acetamide (BAY 60-6583), a new agonist for the human A(2B)AR that was confirmed in preliminary studies to be a potent and highly selective agonist for the murine A(2B)AR. We found that treating mouse neutrophils with low concentrations (10(-9) and 10(-8) M) of BAY 60-6583 inhibited formylated-methionine-leucine-phenylalanine (fMLP)-stimulated superoxide production by either naive neutrophils, tumor necrosis factor-α-primed neutrophils, or neutrophils isolated from mice treated systemically with lipopolysaccharide. This inhibitory action of BAY 60-6583 was confirmed to involve the A(2B)AR in experiments using neutrophils obtained from A(2B)AR gene knockout mice. It is noteworthy that BAY 60-6583 increased fMLP-stimulated superoxide production at higher concentrations (>1 μM), which was attributed to an AR-independent effect. In a standard Boyden chamber migration assay, BAY 60-6583 alone did not stimulate neutrophil chemotaxis or influence chemotaxis in response to fMLP. These results indicate that the A(2B)AR signals to suppress oxidase activity by murine neutrophils, supporting the idea that this low-affinity receptor for adenosine participates along with the A(2A)AR in regulating the proinflammatory actions of neutrophils.
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Affiliation(s)
- Dharini van der Hoeven
- Department of Pharmacology and the Cardiovascular Center, Medical College of Wisconsin, Milwaukee, Wisconsin 53226, USA
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Verzijl D, IJzerman AP. Functional selectivity of adenosine receptor ligands. Purinergic Signal 2011; 7:171-92. [PMID: 21544511 PMCID: PMC3146648 DOI: 10.1007/s11302-011-9232-0] [Citation(s) in RCA: 39] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/24/2011] [Accepted: 04/05/2011] [Indexed: 12/11/2022] Open
Abstract
Adenosine receptors are plasma membrane proteins that transduce an extracellular signal into the interior of the cell. Basically every mammalian cell expresses at least one of the four adenosine receptor subtypes. Recent insight in signal transduction cascades teaches us that the current classification of receptor ligands into agonists, antagonists, and inverse agonists relies very much on the experimental setup that was used. Upon activation of the receptors by the ubiquitous endogenous ligand adenosine they engage classical G protein-mediated pathways, resulting in production of second messengers and activation of kinases. Besides this well-described G protein-mediated signaling pathway, adenosine receptors activate scaffold proteins such as β-arrestins. Using innovative and sensitive experimental tools, it has been possible to detect ligands that preferentially stimulate the β-arrestin pathway over the G protein-mediated signal transduction route, or vice versa. This phenomenon is referred to as functional selectivity or biased signaling and implies that an antagonist for one pathway may be a full agonist for the other signaling route. Functional selectivity makes it necessary to redefine the functional properties of currently used adenosine receptor ligands and opens possibilities for new and more selective ligands. This review focuses on the current knowledge of functionally selective adenosine receptor ligands and on G protein-independent signaling of adenosine receptors through scaffold proteins.
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Affiliation(s)
- Dennis Verzijl
- Division of Medicinal Chemistry, Leiden/Amsterdam Center for Drug Research, Leiden University, PO Box 9502, 2300 RA Leiden, The Netherlands
| | - Ad P. IJzerman
- Division of Medicinal Chemistry, Leiden/Amsterdam Center for Drug Research, Leiden University, PO Box 9502, 2300 RA Leiden, The Netherlands
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31
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Aherne CM, Kewley EM, Eltzschig HK. The resurgence of A2B adenosine receptor signaling. BIOCHIMICA ET BIOPHYSICA ACTA-BIOMEMBRANES 2010; 1808:1329-39. [PMID: 20546702 DOI: 10.1016/j.bbamem.2010.05.016] [Citation(s) in RCA: 126] [Impact Index Per Article: 9.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/17/2010] [Revised: 05/16/2010] [Accepted: 05/17/2010] [Indexed: 01/05/2023]
Abstract
Since its discovery as a low-affinity adenosine receptor (AR), the A2B receptor (A2BAR), has proven enigmatic in its function. The previous discovery of the A2AAR, which shares many similarities with the A2BAR but demonstrates significantly greater affinity for its endogenous ligand, led to the original perception that the A2BAR was not of substantial physiologic relevance. In addition, lack of specific pharmacological agents targeting the A2BAR made its initial characterization challenging. However, the importance of this receptor was reconsidered when it was observed that the A2BAR is highly transcriptionally regulated by factors implicated in inflammatory hypoxia. Moreover, the notion that during ischemia or inflammation extracellular adenosine is dramatically elevated to levels sufficient for A2BAR activation, indicated that A2BAR signaling may be important to dampen inflammation particularly during tissue hypoxia. In addition, the recent advent of techniques for murine genetic manipulation along with development of pharmacological agents with enhanced A2BAR specificity has provided invaluable tools for focused studies on the explicit role of A2BAR signaling in different disease models. Currently, studies performed with combined genetic and pharmacological approaches have demonstrated that A2BAR signaling plays a tissue protective role in many models of acute diseases e.g. myocardial ischemia, or acute lung injury. These studies indicate that the A2BAR is expressed on a wide variety of cell types and exerts tissue/cell specific effects. This is an important consideration for future studies where tissue or cell type specific targeting of the A2BAR may be used as therapeutic approach.
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Affiliation(s)
- Carol M Aherne
- Department of Anesthesiology, University of Colorado, Aurora, CO, USA
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32
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Umapathy NS, Fan Z, Zemskov EA, Alieva IB, Black SM, Verin AD. Molecular mechanisms involved in adenosine-induced endothelial cell barrier enhancement. Vascul Pharmacol 2010; 52:199-206. [PMID: 20045081 PMCID: PMC3868371 DOI: 10.1016/j.vph.2009.12.008] [Citation(s) in RCA: 34] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/22/2009] [Revised: 11/23/2009] [Accepted: 12/20/2009] [Indexed: 01/09/2023]
Abstract
Extracellular adenosine is a physiologically relevant agonist released by various sources, including endothelial cells (EC) and activated platelets, with complex effects mediated via activation of P1 purinergic receptors. Adenosine-induced EC production of glutathione peroxidase1 and nitric oxide is recognized, and an anti-inflammatory mechanism has been described. Effects of extracellular adenosine on the pulmonary EC barrier function and vascular permeability, however, remain poorly characterized. In this study, we demonstrated the adenosine-induced rapid dose-dependent barrier enhancement in human pulmonary artery EC (HPAEC) as measured by an increase in transendothelial electrical resistance (TER). We have shown that HPAEC express only A2A and A2B adenosine receptors. Pharmacological and siRNA depletion studies indicate that A2A, but not A2B receptor activation is required for the adenosine-induced TER increase. Depletion of Galphas with a specific siRNA significantly attenuated the adenosine-induced TER response in HPAEC. In contrast, depletion of either Galphaq or Galphai2 did not affect the adenosine-induced TER increase. This suggests that the adenosine-induced TER increase is cAMP-dependent. The adenosine-induced barrier enhancement effects were associated with a rearrangement of the EC F-actin component of the cytoskeleton, enhanced cell-surface presentation of cell-cell junctional protein VE-cadherin and an involvement of Myosin-light-chain phosphatase (MLCP). Our results suggest, for the first time, that adenosine regulates the EC barrier function via A2A receptors followed by Galphas engagement and is associated with cytoskeletal activation.
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Affiliation(s)
| | - ZhengHong Fan
- Vascular Biology Center, Medical College of Georgia, Augusta, GA 30912
| | - Evgeny A. Zemskov
- Vascular Biology Center, Medical College of Georgia, Augusta, GA 30912
| | - Irina B. Alieva
- Vascular Biology Center, Medical College of Georgia, Augusta, GA 30912
| | - Stephen M. Black
- Vascular Biology Center, Medical College of Georgia, Augusta, GA 30912
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Cagnina RE, Ramos SI, Marshall MA, Wang G, Frazier CR, Linden J. Adenosine A2B receptors are highly expressed on murine type II alveolar epithelial cells. Am J Physiol Lung Cell Mol Physiol 2009; 297:L467-74. [PMID: 19574419 DOI: 10.1152/ajplung.90553.2008] [Citation(s) in RCA: 31] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/21/2023] Open
Abstract
The adenosine A(2B) receptor (A(2B)R) has a wide tissue distribution that includes fibroblasts and endothelial and epithelial cells. The recent generation of an A(2B)R(-/-) mouse constructed with a beta-galactosidase (beta-gal) reporter gene under control of the endogenous promoter has provided a valuable tool to quantify A(2B)R promoter activity (29). To determine the sites of expression of the A(2B) receptor in the mouse lung, histological and flow cytometric analysis of beta-gal reporter gene expression in various lung cell populations was performed. The major site of A(2B)R promoter activity was found to be the type II alveolar epithelial cells (AECs), identified by coexpression of prosurfactant protein C, with relatively less expression in alveolar macrophages, bronchial epithelial cells, and cells of the vasculature. Highly purified type II AECs were prepared by fluorescence-activated sorting of enhanced green fluorescent protein (eGFP)-positive cells from transgenic mice expressing eGFP under control of the surfactant protein C promoter (21). The type II cells expressed 89-fold higher A(2B)R mRNA than pulmonary leukocytes, and the A(2B)R was shown to be functional, as treatment of purified type II AECs with the nonspecific adenosine receptor agonist 5'-N-ethylcarboxamidoadenosine (NECA) induced an increase in intracellular cAMP greater that the beta-adrenergic agonist isoproterenol that was inhibited completely following treatment by ATL-802, a novel, highly potent (K(i) = 8.6 nM), and selective (>900 fold over other adenosine receptor subtypes) antagonist of the mouse A(2B)R.
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Affiliation(s)
- Rebecca E Cagnina
- Robert M. Berne Cardiovascular Research Center, University of Virginia, Charlottesville, VA 22908, USA
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34
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Rodrigues AR, Pignatelli D, Almeida H, Gouveia AM. Melanocortin 5 receptor activates ERK1/2 through a PI3K-regulated signaling mechanism. Mol Cell Endocrinol 2009; 303:74-81. [PMID: 19428994 DOI: 10.1016/j.mce.2009.01.014] [Citation(s) in RCA: 31] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 09/26/2008] [Revised: 01/19/2009] [Accepted: 01/20/2009] [Indexed: 11/24/2022]
Abstract
Melanocortin 5 receptor (MC5R) is a G protein coupled receptor (GPCR) with high affinity for alpha-melanocyte-stimulating hormone (alpha-MSH). To unravel some of the downstream cell-signaling pathways activated by this receptor, HEK293 cells were transiently and stably transfected with a vector encoding green fluorescent protein (GFP)-tagged MC5R. In these cells the receptor was correctly addressed to the cell surface and was functional, as shown by the MC5R-induced formation of intracellular cAMP. In fact, the MC5R agonist alpha-MSH induced a 10- or 16-fold increase (transient or stable cells, respectively) above the cAMP levels found in unstimulated cells. Moreover, in cells stably expressing MC5R-GFP, alpha-MSH promoted ERK1/2 phosphorylation in a dose-dependent manner (EC50=7.3 nM) with the maximal effect occurring after 5 min of agonist incubation. The signaling pathway conveyed through ERK1/2 is not linked to cAMP, since the phosphorylation of these kinases is unchanged by the inhibition of adenylyl cyclase. Also, ERK1/2 activation is not significantly affected by protein kinase A (PKA), protein kinase C (PKC) and protein kinase B or Akt (Akt/PKB) specific inhibitors. However, alpha-MSH-induced ERK1/2 activation is abolished by the phosphatidylinositol 3-kinase (PI3K) inhibitors wortmannin and LY294002. Altogether, these findings demonstrate that MC5R signals through a PI3K-regulated Akt-independent pathway leading to downstream activation of ERK1/2. The involvement of these MAPK suggests that MC5R could be implicated in cellular proliferation or differentiation mechanisms.
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Affiliation(s)
- Adriana R Rodrigues
- Laboratory of Cell and Molecular Biology, Faculty of Medicine of Porto, Portugal
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35
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Auchampach JA, Kreckler LM, Wan TC, Maas JE, van der Hoeven D, Gizewski E, Narayanan J, Maas GE. Characterization of the A2B adenosine receptor from mouse, rabbit, and dog. J Pharmacol Exp Ther 2009; 329:2-13. [PMID: 19141710 DOI: 10.1124/jpet.108.148270] [Citation(s) in RCA: 31] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022] Open
Abstract
We have cloned and pharmacologically characterized the A(2B) adenosine receptor (AR) from the dog, rabbit, and mouse. The full coding regions of the dog and mouse A(2B)AR were obtained by reverse transcriptase-polymerase chain reaction, and the rabbit A(2B)AR cDNA was obtained by screening a rabbit brain cDNA library. It is noteworthy that an additional clone was isolated by library screening that was identical in sequence to the full-length rabbit A(2B)AR, with the exception of a 27-base pair deletion in the region encoding amino acids 103 to 111 (A(2B)AR(103-111)). This 9 amino acid deletion is located in the second intracellular loop at the only known splice junction of the A(2B)AR and seems to result from the use of an additional 5' donor site found in the rabbit and dog but not in the human, rat, or mouse sequences. [(3)H]3-Isobutyl-8-pyrrolidinoxanthine and 8-[4-[((4-cyano-[2,6-(3)H]-phenyl)carbamoylmethyl)oxy]phenyl]-1,3-di(n-propyl)xanthine ([(3)H]MRS 1754) bound with high affinity to membranes prepared from human embryonic kidney (HEK) 293 cells expressing mouse, rabbit, and dog A(2B)ARs. Competition binding studies performed with a panel of agonist (adenosine and 2-amino-3,5-dicyano-4-phenylpyridine analogs) and antagonist ligands identified similar potency orders for the A(2B)AR orthologs, although most xanthine antagonists displayed lower binding affinity for the dog A(2B)AR compared with A(2B)ARs from rabbit and mouse. No specific binding could be detected with membranes prepared from HEK 293 cells expressing the rabbit A(2B)AR(103-111) variant. Furthermore, the variant failed to stimulate adenylyl cyclase or calcium mobilization. We conclude that significant differences in antagonist pharmacology of the A(2B)AR exist between species and that some species express nonfunctional variants of the A(2B)AR due to "leaky" splicing.
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Affiliation(s)
- John A Auchampach
- Department of Pharmacology and Cardiovascular Center, Medical College of Wisconsin, Milwaukee, WI 53226, USA.
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36
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Differential role of the carboxy-terminus of the A(2B) adenosine receptor in stimulation of adenylate cyclase, phospholipase Cbeta, and interleukin-8. Purinergic Signal 2009; 5:289-98. [PMID: 19125355 DOI: 10.1007/s11302-008-9129-8] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/16/2008] [Accepted: 12/10/2008] [Indexed: 10/21/2022] Open
Abstract
In human mast cells and microvascular endothelial cells, the A(2B) adenosine receptor controls at least three independent signaling pathways, i.e., Gs-mediated stimulation of adenylate cyclase, Gq-mediated stimulation of phospholipase Cbeta, and Gs/Gq-independent upregulation of IL-8. Functional analysis of cells transfected with full-length and truncated receptor constructs revealed that the A(2B) receptor C-terminus is important for coupling to Gs and Gq proteins. Removal of the entire cytoplasmic portion in the A(2B) receptor C-terminus rendered it incapable of stimulating adenylate cyclase and phospholipase Cbeta. Conversely, removal of the distal 16 amino acids facilitated signal transduction from the receptor to the downstream Gs but not Gq proteins. However, the A(2B) receptor C-terminus is not essential for upregulation of IL-8. Analysis of chimeric A(2A)/A(2B) receptors demonstrated that only chimeras containing the third intracellular loop of the A(2B) receptor mediated agonist-dependent IL-8 reporter stimulation, suggesting that this domain is important for upregulation of IL-8.
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37
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Raychowdhury MK, Ramos AJ, Zhang P, McLaughin M, Dai XQ, Chen XZ, Montalbetti N, Del Rocío Cantero M, Ausiello DA, Cantiello HF. Vasopressin receptor-mediated functional signaling pathway in primary cilia of renal epithelial cells. Am J Physiol Renal Physiol 2008; 296:F87-97. [PMID: 18945824 DOI: 10.1152/ajprenal.90509.2008] [Citation(s) in RCA: 55] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022] Open
Abstract
The primary cilium of renal epithelial cells is a nonmotile sensory organelle, implicated in mechanosensory transduction signals. Recent studies from our laboratory indicate that renal epithelial primary cilia display abundant channel activity; however, the presence and functional role of specific membrane receptors in this organelle are heretofore unknown. Here, we determined a functional signaling pathway associated with the type 2 vasopressin receptor (V2R) in primary cilia of renal epithelial cells. Besides their normal localization on basolateral membrane, V2R was expressed in primary cilia of LLC-PK(1) renal epithelial cells. The presence of V2R in primary cilia was determined by spontaneous fluorescence of a V2R-gfp chimera and confirmed by immunocytochemical analysis of wild-type LLC-PK(1) cells stained with anti-V2R antibodies and in LLC-PK(1) cells overexpressing the V2R-Flag, with anti-Flag antibody. Ciliary V2R colocalized with adenylyl cyclase (AC) type V/VI in all cell types tested. Functional coupling of the receptors with AC was confirmed by measurement of cAMP production in isolated cilia and by testing AVP-induced cation-selective channel activity either in reconstituted lipid bilayers or subjected to membrane-attached patch clamping. Addition of either 10 microM AVP (trans) or forskolin (cis) in the presence but not the absence of ATP (1 mM, cis) stimulated cation-selective channel activity in ciliary membranes. This channel activity was reduced by addition of the PKA inhibitor PKI. The data provide the first demonstration for the presence of V2R in primary cilia of renal epithelial cells, and a functional cAMP-signaling pathway, which targets ciliary channel function and may help control the sensory function of the primary cilium.
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Affiliation(s)
- Malay K Raychowdhury
- Nephrology Div. and Electrophysiology Core, Massachusetts General Hospital East, 149 13th St., Charlestown, MA 02129, USA
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Bai B, Tang J, Liu H, Chen J, Li Y, Song W. Apelin-13 induces ERK1/2 but not p38 MAPK activation through coupling of the human apelin receptor to the Gi2 pathway. Acta Biochim Biophys Sin (Shanghai) 2008; 40:311-8. [PMID: 18401529 DOI: 10.1111/j.1745-7270.2008.00403.x] [Citation(s) in RCA: 49] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022] Open
Abstract
Apelin signaling to the family of mitogen-activated protein kinases (MAPKs), such as extracellular-regulated kinases 1/2 (ERK1/2) and p38 MAPK, through the coupling of apelin receptor (APJ) to G-protein, mediates important pathophysiological responses. Although apelin fragments have been reported to induce ERK1/2 activation through Gi-protein, the intracellular pathways by which APJ activates these MAPKs are only partially understood. Here, using stably transfected human embryonic kidney 293 (HEK293) cells overexpressing human APJ (HEK293-apelinR), we showed that apelin-13 signaling leads to ERK1/2 and p38 MAPK pathways through APJ activation. It was found in HEK293-apelinR cells that ERK1/2 activation was initiated by apelin-13 at 5 min, with the peak of activation occurring at 15 min, and a return to the basal level within 60 min. The activation of ERK1/2 appeared to be dose-dependent with a significant activation being observed at 10 nM apelin-13 and maximal activation at 100 nM. However, phosphorylated-p38 MAPK was not detected in HEK293-apelinR cells treated with apelin-13. We also shown that the apelin-13-induced ERK1/2 activation requires a coupling with pertussis toxin-sensitive G-protein, and that overexpression of dominant-negative Gi2 completely inhibits the apelin-13-induced ERK1/2 activation. In addition, treatment with apelin-13 resulted in a concentration-dependent reduction of forskolin-stimulated cAMP production. It is therefore suggested that apelin-13 activates ERK1/2 but not p38 MAPK, which involves the coupling of APJ to the Gi2 cascade. In conclusion, the ERK1/2, but not p38 MAPK pathway is activated by apelin-13 through coupling of human APJ to Gi2-protein, which contributes to cellular responses.
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Affiliation(s)
- Bo Bai
- Department of Neurobiology, Taishan Medical College, Taian 271016, China.
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Xu Y, Ravid K, Smith BD. Major histocompatibility class II transactivator expression in smooth muscle cells from A2b adenosine receptor knock-out mice: cross-talk between the adenosine and interferon-gamma signaling. J Biol Chem 2008; 283:14213-20. [PMID: 18359773 DOI: 10.1074/jbc.m708657200] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
Atherosclerosis characterized by sustained inflammation and aberrant extracellular matrix alterations. Our previous investigation has defined major histocompatibility class II transactivator (CIITA) as a key factor in mediating these two processes in smooth muscle cells. Here, we demonstrate that CIITA and major histocompatibility class II expression are elevated in interferon-gamma (IFN-gamma)-treated smooth muscle cells from A2b adenosine receptor (A2bAR(-/-)) knock-out mice, as compared with wild type cells. An A2-type adenosine receptor agonist suppresses these effects of IFN-gamma in wild type cells, which can be blocked by an A2bAR-specific antagonist. We further identify that increased cellular cAMP levels are responsible for the down-regulation of CIITA expression and, hence, reduced IFN-gamma response as evidenced by the following data: 1) direct activation of adenylyl cyclase activity is both necessary and sufficient to suppress the IFN-gamma response; 2) inhibition of phosphodiesterase activity attenuates IFN-gamma induced transcription events; and 3) direct treatment with cAMP analog abrogates CIITA activation and IFN-gamma response. Therefore, our data establish possible cross-talk between the adenosine signaling through cAMP and IFN-gamma during regulation of CIITA expression.
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Affiliation(s)
- Yong Xu
- Department of Biochemistry, Boston University School of Medicine, Boston, MA 02118, USA
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Casella I, Lindner H, Zenzmaier C, Riitano D, Berger P, Costa T. Non-gonadotropin-releasing hormone-mediated transcription and secretion of large human glycoprotein hormone alpha-subunit in human embryonic kidney-293 cells. Endocrinology 2008; 149:1144-54. [PMID: 18079192 DOI: 10.1210/en.2007-1529] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/19/2022]
Abstract
To identify genes that are most responsive to a sustained activation of a G(s) protein-coupled receptor, HEK293 cells were stably transfected with the beta(2)-adrenergic receptor and stimulated with agonist isoproterenol (1 mum). A microarray study indicated that the gene with the highest stimulation index (500-fold) encoded the common alpha-subunit of human glycoprotein hormones (GPHalpha). Induction of GPHalpha transcription in response to cAMP elevations resulted in a dramatic increase (600-fold) of protein secretion as shown by RT-PCR and a highly specific time-resolved immunofluorometric assay. Cloning and sequencing of the GPHalpha cDNA and mass spectrometric analysis of HPLC-purified GPHalpha derived from serum-free HEK293-beta(2)-adrenergic receptor-stimulated cells verified the nature of the molecule. Enzymatic deglycosylation with subsequent Western blots revealed that this was a large hyperglycosylated form of GPHalpha that had not been associated with a beta-subunit previously. This uncombined variant is known to be either cosecreted with GPHs from the pituitary, the placenta, and a variety of tumors or secreted without GPHs from APUD cells and rare tumors. Moreover, it is similar to GPHalpha found at high concentrations in seminal plasma. As shown by a panel of endogenous or transfected G protein-coupled receptors in HEK293 cells, the expression of large GPHalpha was controlled by G(s)- and G(q)- but not G(i)-dependent receptors and mediated via cAMP and Ca(++) release. This suggests that Gq- or G(s)-coupled receptors other than the classical GnRH receptor may play a role in the regulation of nonpituitary, nonplacental GPHalpha secretion under physiological and pathological conditions.
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Affiliation(s)
- Ida Casella
- Department of Pharmacology, Istituto Superiore di Sanità, Viale Regina Elena 299, 00161 Rome, Italy
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Abstract
The A2b adenosine receptor (A2bAR) is highly abundant in bone marrow macrophages and vascular smooth muscle cells (VSMC). To examine the functional significance of this receptor expression, we applied a femoral artery injury model to A2bAR knockout (KO) mice and showed that the A2bAR prevents vascular lesion formation in an injury model that resembles human restenosis after angioplasty. While considering related mechanisms, we noted higher levels of TNF-alpha, an up-regulator of CXCR4, and of VSMC proliferation in the injured KO mice. In accordance, CXCR4, which is known to attract progenitor cells during tissue regeneration, is up-regulated in lesions of the KO mice. In addition, aortic smooth muscle cells derived from A2bAR KO mice display greater proliferation in comparison with controls. Bone marrow transplantation experiments indicated that the majority of the signal for lesion formation in the null mice originates from bone marrow cells. Thus, this study highlights the significance of the A2bAR in regulating CXCR4 expression in vivo and in protecting against vascular lesion formation.
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Köles L, Gerevich Z, Oliveira JF, Zadori ZS, Wirkner K, Illes P. Interaction of P2 purinergic receptors with cellular macromolecules. Naunyn Schmiedebergs Arch Pharmacol 2007; 377:1-33. [DOI: 10.1007/s00210-007-0222-2] [Citation(s) in RCA: 41] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/06/2007] [Accepted: 11/12/2007] [Indexed: 02/04/2023]
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Dip RG. Adenosine receptor modulation: potential implications in veterinary medicine. Vet J 2007; 179:38-49. [PMID: 17904398 DOI: 10.1016/j.tvjl.2007.08.005] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/20/2007] [Revised: 07/27/2007] [Accepted: 08/02/2007] [Indexed: 12/01/2022]
Abstract
Adenosine is a purine nucleoside whose concentration increases during inflammation and hypoxia and the many roles of this molecule are becoming better understood. Increased reactivity to adenosine of the airways of asthmatic but not of normal subjects underlines the role of adenosine in airway inflammation. The identification and pharmacological characterisation of different adenosine receptors have stimulated the search for subtype-specific ligands able to modulate the effects of this molecule in a directed way. Several compounds of different chemical classes have been identified as having potential drawbacks, including side effects resulting from the broad distribution of the receptors across the organism, have prevented clinical application. In this article, the effects of adenosine's different receptors and the intracellular signalling pathways are reviewed. The potential of adenosine receptor modulation as a therapeutic target for chronic airway inflammation is considered, taking equine recurrent airway disease and feline asthma as examples of naturally occurring airway obstructive diseases. Other potential applications for adenosine receptor modulation are also discussed. As the intrinsic molecular events of adenosine's mechanism of action become uncovered, new concrete therapeutic approaches will become available for the treatment of various conditions in veterinary medicine.
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Affiliation(s)
- Ramiro G Dip
- Institute of Pharmacology and Toxicology, University of Zurich-Vetsuisse, Winterthurerstrasse 260, CH-8057 Zurich, Switzerland.
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Fang Y, Olah ME. Cyclic AMP-dependent, protein kinase A-independent activation of extracellular signal-regulated kinase 1/2 following adenosine receptor stimulation in human umbilical vein endothelial cells: role of exchange protein activated by cAMP 1 (Epac1). J Pharmacol Exp Ther 2007; 322:1189-200. [PMID: 17565009 DOI: 10.1124/jpet.107.119933] [Citation(s) in RCA: 65] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022] Open
Abstract
A critical process in angiogenesis is endothelial cell proliferation, which requires activation of extracellular signal-regulated kinase (ERK)1/2. This study analyzed the pathway responsible for adenosine-induced ERK1/2 phosphorylation in human umbilical vein endothelial cells (HUVEC). Characterization with adenosine receptor (AR) agonists and antagonists and the AR mRNA profile demonstrated that stimulation of the A(2B)AR can mediate ERK1/2 phosphorylation in HUVEC. The lack of sensitivity of A(2B)AR-mediated ERK1/2 phosphorylation to 3-[1-[3-(dimethylaminopropyl]-1H-indol-3-yl]-4-(1H-indol-3-yl)-1H-pyrrole-2,5-dione monohydrochloride (GF109203X) and 3-[1-[3-(amidinothio)propyl]-1H-in-dol-3-yl]-3-(1-methyl-1H-indol-3-yl) maleimide (bisindolylmaleimide IX) (Ro31-8220) indicated that protein kinase C stimulation is not required. The response did not involve transactivation of receptors for epidermal growth factor or vascular endothelial growth factor (VEGF). The A(2B)AR-mediated response required functional G(alphas) and was mimicked by forskolin and 8-bromoadenosine 3',5'-cyclic monophosphate. However, ERK1/2 phosphorylation induced by A(2B)AR stimulation and forskolin was insensitive to protein kinase A inhibitors. It was hypothesized that the A(2B)AR-mediated ERK1/2 activation may involve exchange protein activated by cAMP (Epac), a cAMP-activated guanine nucleotide exchange factor for Rap GTPases. Reverse Transcription-polymerase chain reaction analysis detected Epac1 but not Epac2 in HUVEC. 8-(p-Chlorophenylthio)-2'-O-methyladenosine-3',5'-cyclic monophosphate (8CPT-2Me-cAMP), an Epac activator, stimulated ERK1/2 phosphorylation. Overexpression of Epac1 enhanced A(2B)AR-mediated and forskolin-induced ERK1/2 phosphorylation, whereas response to VEGF was unaffected. Inhibition of Epac1 expression with small interfering RNA substantially reduced A(2B)AR-mediated and forskolin-induced ERK1/2 phosphorylation and abolished that by 8CPT-2Me-cAMP. A(2B)AR stimulation and forskolin activated Rap1. Expression of a dominant-negative Ras protein did not affect either forskolin-induced or A(2B)AR-mediated ERK1/2 phosphorylation. In summary, Epac1 activation in HUVEC results in ERK1/2 activation, and this protein, at least in part, mediates response to the physiologically relevant event of A(2B)AR stimulation.
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Affiliation(s)
- Ying Fang
- Department of Pharmacology and Cell Biophysics, College of Medicine, University of Cincinnati, Ohio, USA
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Hermansson NO, Morgan DGA, Drmota T, Larsson N. Adenosine is not a direct GHSR agonist--artificial cross-talk between GHSR and adenosine receptor pathways. Acta Physiol (Oxf) 2007; 190:77-86. [PMID: 17428235 DOI: 10.1111/j.1365-201x.2007.01691.x] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/26/2022]
Abstract
AIM To assess if adenosine is a direct growth hormone secretagogue receptor (GHSR) agonist by investigating the mechanism behind adenosine induced calcium release in human embryonic kidney 293s (HEK) cells expressing GHSR. METHODS Calcium mobilization, cyclic adenosine monophosphate (cAMP) and IP(3) experiments were performed using HEK cells stably expressing GHSR and/or adenosine A(2B) receptor (A(2B)R). RESULTS Adenosine has been widely reported as a GHSR agonist. In our hands, adenosine and forskolin stimulated calcium release from IP(3) controlled stores in HEK-GHSR cells but not in non-transfected HEK cells. This release was not accompanied by increased IP(3) levels. The calcium release was both cholera toxin and U73122 sensitive, indicating the involvement of both Galpha(s)/adenylyl cyclase and Galpha(q/11)/phospholipase C pathways. Importantly, the GHSR inverse agonist [D-Arg(1) D-Phe(5) D-Trp(7,9) Leu(11)]-Substance P (SP-analogue) blocked the adenosine stimulated calcium release, demonstrating that GHSR is involved. Assessment of the GHSR-dependent calcium release using adenosine receptor agonists and antagonists resulted in a rank order of potencies resembling the profile of A(2B)R. A(2B)R over-expression in HEK-GHSR cells enhanced potency and efficacy of the adenosine induced calcium release without increasing IP(3) production. Moreover, A(2B)R over-expression in HEK cells potentiated NECA-induced cAMP production. However, GHSR expression had no effect on intracellular cAMP production. CONCLUSION In HEK-GHSR cells adenosine activates endogenously expressed A(2B)R resulting in calcium mobilization. We hypothesize that the responsible mechanism is cAMP-dependent sensitization of IP(3) receptors for the high basal level of IP(3) caused by GHSR constitutive activity. Altogether, our results demonstrate that adenosine is not a direct GHSR agonist.
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Affiliation(s)
- N-O Hermansson
- Department of Lead Generation, AstraZeneca R&D Mölndal, Mölndal, Sweden
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Lahiri S, Mitchell CH, Reigada D, Roy A, Cherniack NS. Purines, the carotid body and respiration. Respir Physiol Neurobiol 2007; 157:123-9. [PMID: 17383945 PMCID: PMC1975770 DOI: 10.1016/j.resp.2007.02.015] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/11/2006] [Revised: 02/19/2007] [Accepted: 02/21/2007] [Indexed: 10/23/2022]
Abstract
The carotid body is essential to detecting levels of oxygen in the blood and initiating the compensatory response. Increasing evidence suggests that the purines ATP and adenosine make a key contribution to this signaling by the carotid body. The glomus cells release ATP in response to hypoxia. This released ATP can stimulate P2X receptors on the carotid body to elevate intracellular Ca(2+) and to produce an excitatory response. This released ATP can be dephosphorylated to adenosine by a series of extracellular enzymes, which in turn can stimulate A(1), A(2A) and A(2B) adenosine receptors. Levels of extracellular adenosine can also be altered by membrane transporters. Endogenous adenosine stimulates these receptors to increase the ventilation rate and may modulate the catecholamine release from the carotid sinus nerve. Prolonged hypoxic challenge can alter the expression of purinergic receptors, suggesting a role in the adaptation. This review discusses evidence for a key role of ATP and adenosine in the hypoxic response of the carotid body, and emphasizes areas of new contributions likely to be important in the future.
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Affiliation(s)
- S. Lahiri
- Department of Physiology; University of Pennsylvania School of Medicine, Philadelphia, PA
| | - C. H. Mitchell
- Department of Physiology; University of Pennsylvania School of Medicine, Philadelphia, PA
| | - D. Reigada
- Department of Physiology; University of Pennsylvania School of Medicine, Philadelphia, PA
| | - A. Roy
- Department of Physiology; University of Pennsylvania School of Medicine, Philadelphia, PA
| | - N. S. Cherniack
- Departments of Medicine and Physiology, Case Western Reserve School of Medicine, Cleveland, OH
- Department of Medicine University of Medicine and Dentistry of New Jersey, Newark, NJ
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Iino M, Ehama R, Nakazawa Y, Iwabuchi T, Ogo M, Tajima M, Arase S. Adenosine stimulates fibroblast growth factor-7 gene expression via adenosine A2b receptor signaling in dermal papilla cells. J Invest Dermatol 2007; 127:1318-25. [PMID: 17301835 DOI: 10.1038/sj.jid.5700728] [Citation(s) in RCA: 57] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
Abstract
It has been previously reported that an adenosine receptor-mediated signal-transduction pathway in the dermal papilla cells (DPCs) of hair contributes to minoxidil-induced hair growth. In this study, we investigated this hypothesis further and have elucidated some underlying mechanisms. We performed DNA microarray analyses of DPCs and found that adenosine stimulation increases fibroblast growth factor-7 (FGF-7) gene expression levels by greater than 2-fold. Elevations of the extracellular FGF-7 protein levels were also observed. These upregulations of FGF-7 both at mRNA and protein levels were inhibited by A2b adenosine receptor-specific antagonist, alloxazine, but not by antagonists for other subtypes. In addition, the intracellular cAMP levels were raised by adenosine in a dose-dependent manner. Moreover, an increase of intracellular cAMP augmented the FGF-7 upregulation. Taken together, these results show that adenosine treatment of DPCs upregulates FGF-7 expression via the A2b adenosine receptor and that cAMP acts as one of the second messengers in this pathway. Furthermore, treatment with FGF-7 at concentrations of 10 ng/ml or greater significantly stimulated hair fiber elongation in human scalp hair follicle organ cultures. These data imply that adenosine might stimulate hair growth through FGF-7 upregulation in DPCs.
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Sun CX, Zhong H, Mohsenin A, Morschl E, Chunn JL, Molina JG, Belardinelli L, Zeng D, Blackburn MR. Role of A2B adenosine receptor signaling in adenosine-dependent pulmonary inflammation and injury. J Clin Invest 2006; 116:2173-2182. [PMID: 16841096 PMCID: PMC1501110 DOI: 10.1172/jci27303] [Citation(s) in RCA: 206] [Impact Index Per Article: 11.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/02/2005] [Accepted: 05/23/2006] [Indexed: 01/15/2023] Open
Abstract
Adenosine has been implicated in the pathogenesis of chronic lung diseases such as asthma and chronic obstructive pulmonary disease. In vitro studies suggest that activation of the A2B adenosine receptor (A2BAR) results in proinflammatory and profibrotic effects relevant to the progression of lung diseases; however, in vivo data supporting these observations are lacking. Adenosine deaminase-deficient (ADA-deficient) mice develop pulmonary inflammation and injury that are dependent on increased lung adenosine levels. To investigate the role of the A2BAR in vivo, ADA-deficient mice were treated with the selective A2BAR antagonist CVT-6883, and pulmonary inflammation, fibrosis, and airspace integrity were assessed. Untreated and vehicle-treated ADA-deficient mice developed pulmonary inflammation, fibrosis, and enlargement of alveolar airspaces; conversely, CVT-6883-treated ADA-deficient mice showed less pulmonary inflammation, fibrosis, and alveolar airspace enlargement. A2BAR antagonism significantly reduced elevations in proinflammatory cytokines and chemokines as well as mediators of fibrosis and airway destruction. In addition, treatment with CVT-6883 attenuated pulmonary inflammation and fibrosis in wild-type mice subjected to bleomycin-induced lung injury. These findings suggest that A2BAR signaling influences pathways critical for pulmonary inflammation and injury in vivo. Thus in chronic lung diseases associated with increased adenosine, antagonism of A2BAR-mediated responses may prove to be a beneficial therapy.
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Affiliation(s)
- Chun-Xiao Sun
- Department of Biochemistry and Molecular Biology, University of Texas Medical School at Houston, Houston, Texas, USA.
Department of Drug Research and Pharmacological Sciences, CV Therapeutics Inc., Palo Alto, California, USA
| | - Hongyan Zhong
- Department of Biochemistry and Molecular Biology, University of Texas Medical School at Houston, Houston, Texas, USA.
Department of Drug Research and Pharmacological Sciences, CV Therapeutics Inc., Palo Alto, California, USA
| | - Amir Mohsenin
- Department of Biochemistry and Molecular Biology, University of Texas Medical School at Houston, Houston, Texas, USA.
Department of Drug Research and Pharmacological Sciences, CV Therapeutics Inc., Palo Alto, California, USA
| | - Eva Morschl
- Department of Biochemistry and Molecular Biology, University of Texas Medical School at Houston, Houston, Texas, USA.
Department of Drug Research and Pharmacological Sciences, CV Therapeutics Inc., Palo Alto, California, USA
| | - Janci L. Chunn
- Department of Biochemistry and Molecular Biology, University of Texas Medical School at Houston, Houston, Texas, USA.
Department of Drug Research and Pharmacological Sciences, CV Therapeutics Inc., Palo Alto, California, USA
| | - Jose G. Molina
- Department of Biochemistry and Molecular Biology, University of Texas Medical School at Houston, Houston, Texas, USA.
Department of Drug Research and Pharmacological Sciences, CV Therapeutics Inc., Palo Alto, California, USA
| | - Luiz Belardinelli
- Department of Biochemistry and Molecular Biology, University of Texas Medical School at Houston, Houston, Texas, USA.
Department of Drug Research and Pharmacological Sciences, CV Therapeutics Inc., Palo Alto, California, USA
| | - Dewan Zeng
- Department of Biochemistry and Molecular Biology, University of Texas Medical School at Houston, Houston, Texas, USA.
Department of Drug Research and Pharmacological Sciences, CV Therapeutics Inc., Palo Alto, California, USA
| | - Michael R. Blackburn
- Department of Biochemistry and Molecular Biology, University of Texas Medical School at Houston, Houston, Texas, USA.
Department of Drug Research and Pharmacological Sciences, CV Therapeutics Inc., Palo Alto, California, USA
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Gessi S, Varani K, Merighi S, Leung E, Mac Lennan S, Baraldi PG, Borea PA. Novel selective antagonist radioligands for the pharmacological study of A(2B) adenosine receptors. Purinergic Signal 2006; 2:583-8. [PMID: 18404460 PMCID: PMC2096665 DOI: 10.1007/s11302-006-9019-x] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/01/2005] [Revised: 05/09/2006] [Accepted: 05/29/2006] [Indexed: 11/28/2022] Open
Abstract
The adenosine A2B receptor is the least well characterized of the four adenosine subtypes due to the lack of potent and selective agonists and antagonists. Despite the widespread distribution of A2B receptor mRNA, little information is available with regard to their function. The characterization of A2B receptors, through radioligand binding studies, has been performed, until now, by using low-affinity and non-selective antagonists like 1,3-dipropyl-8-cyclopentylxanthine ([3H]DPCPX),(4-(2-[7-amino-2-(2-furyl)-[1,2,4]triazolo-[2,3-a][1,3,5]triazin-5-ylamino]ethyl)-phenol ([3H]ZM 241385) and 3-(3,4-aminobenzyl)-8-(4-oxyacetate)phenyl-1-propyl-xanthine ([125I]ABOPX). Recently, high-affinity radioligands for A2B receptors, [N-(4-cyanophenyl)-2-[4-(2,3,6,7-tetrahydro-2,6-dioxo-1,3-dipropyl-1H-purin-8-yl)-phenoxy]acetamide ([3H]MRS 1754), N-(2-(2-Phenyl-6-[4-(2,2,3,3-tetratritrio-3-phenylpropyl)-piperazine-1-carbonyl]-7H-pyrrolo[2,3-d]pyrimidin-4-ylamino)-ethyl)-acetamide ([3H]OSIP339391) and N-benzo[1,3]dioxol-5-yl-2-[5-(1,3-dipropyl-2,6-dioxo-2,3,6,7-tetrahydro-1H-purin-8-yl)-1-methyl-1H-pyrazol-3-yloxy]-acetamide] ([3H]MRE 2029F20), have been introduced. This minireview offers an overview of these recently developed radioligands and the most important applications of drugs towards A2B receptors.
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Affiliation(s)
- Stefania Gessi
- Department of Clinical and Experimental Medicine, Pharmacology Unit and ‘Interdisciplinary Center for the Study of Inflammation (ICSI),′, Ferrara, Italy
| | - Katia Varani
- Department of Clinical and Experimental Medicine, Pharmacology Unit and ‘Interdisciplinary Center for the Study of Inflammation (ICSI),′, Ferrara, Italy
| | - Stefania Merighi
- Department of Clinical and Experimental Medicine, Pharmacology Unit and ‘Interdisciplinary Center for the Study of Inflammation (ICSI),′, Ferrara, Italy
| | - Edward Leung
- King Pharmaceuticals Research & Development, Cary, NC USA
| | | | | | - Pier Andrea Borea
- Department of Clinical and Experimental Medicine, Pharmacology Unit and ‘Interdisciplinary Center for the Study of Inflammation (ICSI),′, Ferrara, Italy
- Faculty of Medicine, Department of Clinical and Experimental Medicine, Pharmacology Unit, University of Ferrara,, Via Fossato di Mortara 17-19, 44100 Ferrara, Italy
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Kolachala VL, Obertone TS, Wang L, Merlin D, Sitaraman SV. Adenosine 2b receptor (A2bR) signals through adenylate cyclase (AC) 6 isoform in the intestinal epithelial cells. Biochim Biophys Acta Gen Subj 2006; 1760:1102-8. [PMID: 16631311 DOI: 10.1016/j.bbagen.2006.03.010] [Citation(s) in RCA: 16] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/02/2006] [Revised: 03/06/2006] [Accepted: 03/09/2006] [Indexed: 11/29/2022]
Abstract
Adenosine 2b receptor (A2bR), a G-protein coupled receptor positively coupled to adenylate cyclase, mediates key events such as chloride, IL-6 and fibronectin secretion in intestinal epithelial cells and is upregulated during intestinal inflammation. In order to gain insight into the overall mechanism of A2bR activation, in this study, we sought to characterize the AC isoform associated with A2bR signaling. The colonic epithelial cell line T84, expressing only the A2b subtype of adenosine receptor, and Chinese hamster ovary (CHO) cells, were used in these studies. cAMP was measured by luminometric assay and AC isoform expression was determined by Western blot, RT-PCR, isoform-specific stealth RNAi and Quantigene. T84 and CHO cells express all nine known AC isoforms. In order to characterize which AC isoform(s) are associated with A2bR, we used the differential inhibition of specific AC isoforms by calcium and nitric oxide. Pretreatment of cells with carbachol or nitric oxide donors such as S-Nitroso-N-acetylpencillamine (SNAP) and PAPANANOATE inhibited A2bR mediated increase in cAMP. Further, overexpression of AC-5 or AC-6 potentiated A2bR-mediated increases in cAMP levels. Finally, transfection with AC isoform-specific RNAi demonstrated that AC-6 but not AC-5 RNAi inhibited adenosine-induced cAMP levels. Taken together, these results suggest that A2bR mediates signaling through AC-6 isoform. Since pro-inflammatory cytokines such as interferon-gamma (IFN-gamma) modulate the expression of specific AC isoforms in the intestinal epithelia, our observation may have therapeutic implications for intestinal inflammation or diarrhea wherein aA2bR is upregulated.
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Affiliation(s)
- Vasantha L Kolachala
- Division of Digestive Diseases, Department of Medicine, Emory University, Room 201-F, 615 Michael Street, Whitehead Research Building, Atlanta, GA 30322, USA
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