1
|
Gao ZG, Auchampach JA, Jacobson KA. Species dependence of A 3 adenosine receptor pharmacology and function. Purinergic Signal 2023; 19:523-550. [PMID: 36538251 PMCID: PMC9763816 DOI: 10.1007/s11302-022-09910-1] [Citation(s) in RCA: 6] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/22/2022] [Accepted: 11/26/2022] [Indexed: 12/24/2022] Open
Abstract
Efforts to fully understand pharmacological differences between G protein-coupled receptor (GPCR) species homologues are generally not pursued in detail during the drug development process. To date, many GPCRs that have been successfully targeted are relatively well-conserved across species in amino acid sequence and display minimal variability of biological effects. However, the A3 adenosine receptor (AR), an exciting drug target for a multitude of diseases associated with tissue injury, ischemia, and inflammation, displays as little as 70% sequence identity among mammalian species (e.g., rodent vs. primate) commonly used in drug development. Consequently, the pharmacological properties of synthetic A3AR ligands vary widely, not only in binding affinity, selectivity, and signaling efficacy, but to the extent that some function as agonists in some species and antagonists in others. Numerous heterocyclic antagonists that have nM affinity at the human A3AR are inactive or weakly active at the rat and mouse A3ARs. Positive allosteric modulators, including the imidazo [4,5-c]quinolin-4-amine derivative LUF6000, are only active at human and some larger animal species that have been evaluated (rabbit and dog), but not rodents. A3AR agonists evoke systemic degranulation of rodent, but not human mast cells. The rat A3AR undergoes desensitization faster than the human A3AR, but the human homologue can be completely re-sensitized and recycled back to the cell surface. Thus, comprehensive pharmacological evaluation and awareness of potential A3AR species differences are critical in studies to further understand the basic biological functions of this unique AR subtype. Recombinant A3ARs from eight different species have been pharmacologically characterized thus far. In this review, we describe in detail current knowledge of species differences in genetic identity, G protein-coupling, receptor regulation, and both orthosteric and allosteric A3AR pharmacology.
Collapse
Affiliation(s)
- Zhan-Guo Gao
- Molecular Recognition Section, Laboratory of Bioorganic Chemistry, National Institute of Diabetes and Digestive and Kidney Diseases, National Institutes of Health, Bethesda, MD, 20892-0810, USA.
| | - John A Auchampach
- Department of Pharmacology and Toxicology, and the Cardiovascular Center, Medical College of Wisconsin, 8701 Watertown Plank Road, Milwaukee, WI, 53226, USA
| | - Kenneth A Jacobson
- Molecular Recognition Section, Laboratory of Bioorganic Chemistry, National Institute of Diabetes and Digestive and Kidney Diseases, National Institutes of Health, Bethesda, MD, 20892-0810, USA.
| |
Collapse
|
2
|
Harvey JB, Phan LH, Villarreal OE, Bowser JL. CD73's Potential as an Immunotherapy Target in Gastrointestinal Cancers. Front Immunol 2020; 11:508. [PMID: 32351498 PMCID: PMC7174602 DOI: 10.3389/fimmu.2020.00508] [Citation(s) in RCA: 55] [Impact Index Per Article: 13.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/30/2019] [Accepted: 03/05/2020] [Indexed: 02/06/2023] Open
Abstract
CD73, a cell surface 5'nucleotidase that generates adenosine, has emerged as an attractive therapeutic target for reprogramming cancer cells and the tumor microenvironment to dampen antitumor immune cell evasion. Decades of studies have paved the way for these findings, starting with the discovery of adenosine signaling, particularly adenosine A2A receptor (A2AR) signaling, as a potent suppressor of tissue-devastating immune cell responses, and evolving with studies focusing on CD73 in breast cancer, melanoma, and non-small cell lung cancer. Gastrointestinal (GI) cancers are a major cause of cancer-related deaths. Evidence is mounting that shows promise for improving patient outcomes through incorporation of immunomodulatory strategies as single agents or in combination with current treatment options. Recently, several immune checkpoint inhibitors received FDA approval for use in GI cancers; however, clinical benefit is limited. Investigating molecular mechanisms promoting immunosuppression, such as CD73, in GI cancers can aid in current efforts to extend the efficacy of immunotherapy to more patients. In this review, we discuss current clinical and basic research studies on CD73 in GI cancers, including gastric, liver, pancreatic, and colorectal cancer, with special focus on the potential of CD73 as an immunotherapy target in these cancers. We also present a summary of current clinical studies targeting CD73 and/or A2AR and combination of these therapies with immune checkpoint inhibitors.
Collapse
Affiliation(s)
- Jerry B. Harvey
- Department of Anesthesiology, The University of Texas Health Science Center at Houston, Houston, TX, United States
| | - Luan H. Phan
- Department of Anesthesiology, The University of Texas Health Science Center at Houston, Houston, TX, United States
| | - Oscar E. Villarreal
- Department of Gastrointestinal Medical Oncology, The University of Texas MD Anderson Cancer Center, Houston, TX, United States
| | - Jessica L. Bowser
- Department of Anesthesiology, The University of Texas Health Science Center at Houston, Houston, TX, United States
| |
Collapse
|
3
|
Yang X, van Veldhoven JPD, Offringa J, Kuiper BJ, Lenselink EB, Heitman LH, van der Es D, IJzerman AP. Development of Covalent Ligands for G Protein-Coupled Receptors: A Case for the Human Adenosine A 3 Receptor. J Med Chem 2019; 62:3539-3552. [PMID: 30869893 PMCID: PMC6466477 DOI: 10.1021/acs.jmedchem.8b02026] [Citation(s) in RCA: 28] [Impact Index Per Article: 5.6] [Reference Citation Analysis] [Abstract] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/14/2022]
Abstract
The development of covalent ligands for G protein-coupled receptors (GPCRs) is not a trivial process. Here, we report a streamlined workflow thereto from synthesis to validation, exemplified by the discovery of a covalent antagonist for the human adenosine A3 receptor (hA3AR). Based on the 1 H,3 H-pyrido[2,1- f]purine-2,4-dione scaffold, a series of ligands bearing a fluorosulfonyl warhead and a varying linker was synthesized. This series was subjected to an affinity screen, revealing compound 17b as the most potent antagonist. In addition, a nonreactive methylsulfonyl derivative 19 was developed as a reversible control compound. A series of assays, comprising time-dependent affinity determination, washout experiments, and [35S]GTPγS binding assays, then validated 17b as the covalent antagonist. A combined in silico hA3AR-homology model and site-directed mutagenesis study was performed to demonstrate that amino acid residue Y2657.36 was the unique anchor point of the covalent interaction. This workflow might be applied to other GPCRs to guide the discovery of covalent ligands.
Collapse
Affiliation(s)
- Xue Yang
- Division of Drug Discovery and Safety, Leiden Academic Centre for Drug Research , Leiden University , Einsteinweg 55 , 2333 CC Leiden , The Netherlands
| | - Jacobus P D van Veldhoven
- Division of Drug Discovery and Safety, Leiden Academic Centre for Drug Research , Leiden University , Einsteinweg 55 , 2333 CC Leiden , The Netherlands
| | - Jelle Offringa
- Division of Drug Discovery and Safety, Leiden Academic Centre for Drug Research , Leiden University , Einsteinweg 55 , 2333 CC Leiden , The Netherlands
| | - Boaz J Kuiper
- Division of Drug Discovery and Safety, Leiden Academic Centre for Drug Research , Leiden University , Einsteinweg 55 , 2333 CC Leiden , The Netherlands
| | - Eelke B Lenselink
- Division of Drug Discovery and Safety, Leiden Academic Centre for Drug Research , Leiden University , Einsteinweg 55 , 2333 CC Leiden , The Netherlands
| | - Laura H Heitman
- Division of Drug Discovery and Safety, Leiden Academic Centre for Drug Research , Leiden University , Einsteinweg 55 , 2333 CC Leiden , The Netherlands
| | - Daan van der Es
- Division of Drug Discovery and Safety, Leiden Academic Centre for Drug Research , Leiden University , Einsteinweg 55 , 2333 CC Leiden , The Netherlands
| | - Adriaan P IJzerman
- Division of Drug Discovery and Safety, Leiden Academic Centre for Drug Research , Leiden University , Einsteinweg 55 , 2333 CC Leiden , The Netherlands
| |
Collapse
|
4
|
Gao ZG, Jacobson KA. Purinergic Signaling in Mast Cell Degranulation and Asthma. Front Pharmacol 2017; 8:947. [PMID: 29311944 PMCID: PMC5744008 DOI: 10.3389/fphar.2017.00947] [Citation(s) in RCA: 52] [Impact Index Per Article: 7.4] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/16/2017] [Accepted: 12/14/2017] [Indexed: 11/13/2022] Open
Abstract
Mast cells are responsible for the majority of allergic conditions. It was originally thought that almost all allergic events were mediated directly only via the high-affinity immunoglobulin E receptors. However, recent evidence showed that many other receptors, such as G protein-coupled receptors and ligand-gated ion channels, are also directly involved in mast cell degranulation, the release of inflammatory mediators such as histamine, serine proteases, leukotrienes, heparin, and serotonin. These mediators are responsible for the symptoms in allergic conditions such as allergic asthma. In recent years, it has been realized that purinergic signaling, induced via the activation of G protein-coupled adenosine receptors and P2Y nucleotide receptors, as well as by ATP-gated P2X receptors, plays a significant role in mast cell degranulation. Both adenosine and ATP can induce degranulation and bronchoconstriction on their own and synergistically with allergens. All three classes of receptors, adenosine, P2X and P2Y are involved in tracheal mucus secretion. This review will summarize the currently available knowledge on the role of purinergic signaling in mast cell degranulation and its most relevant disease, asthma.
Collapse
Affiliation(s)
- Zhan-Guo Gao
- Molecular Recognition Section, Laboratory of Bioorganic Chemistry, National Institute of Diabetes and Digestive and Kidney Diseases, National Institutes of Health, Bethesda, MD, 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, Bethesda, MD, United States
| |
Collapse
|
5
|
Hosoi T, Ino S, Ohnishi F, Todoroki K, Yoshii M, Kakimoto M, Müller CE, Ozawa K. Mechanisms of the action of adenine on anti-allergic effects in mast cells. IMMUNITY INFLAMMATION AND DISEASE 2017; 6:97-105. [PMID: 29094492 PMCID: PMC5818451 DOI: 10.1002/iid3.200] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 04/10/2017] [Revised: 09/11/2017] [Accepted: 09/14/2017] [Indexed: 12/19/2022]
Abstract
Introduction Mast cells play an important role in allergic responses. Methods We herein demonstrated the mechanisms of inhibitory effect of adenine on IgE/antigen‐induced degranulation and TNF‐α release in mast cells. Results We found that these effects were dependent on the amino group of adenine because purine only weakly inhibited degranulation. Adenine also inhibited Ca2+ ionophore‐ and thapsigargin‐induced degranulation, however, this inhibitory effect was weaker than that of the antigen. Therefore, the inhibitory effects of adenine on degranulation may be mediated before as well as after the Ca2+ raise under the antigen stimulus. Adenine inhibited antigen‐induced Syk and the subsequent induction of AKT and ERK activation under FcϵRI‐mediated signal. Adenine also attenuated antigen‐induced increase in Ca2+. Furthermore, adenine inhibited IgE/antigen‐induced IKKα/β activation, which is involved in degranulation. Finally, adenine protected mice against anaphylactic allergic responses in vivo. Conclusions The present study revealed a key role of adenine in the attenuation of allergic responses through the inhibition of Syk‐mediated signal transduction and IKK‐mediated degranulation.
Collapse
Affiliation(s)
- Toru Hosoi
- Department of Pharmacotherapy, Graduate School of Biomedical and Health Sciences, Hiroshima University, 1-2-3 Kasumi, Minami-ku, Hiroshima 734-8551, Japan
| | - Shinsuke Ino
- Department of Pharmacotherapy, Graduate School of Biomedical and Health Sciences, Hiroshima University, 1-2-3 Kasumi, Minami-ku, Hiroshima 734-8551, Japan
| | - Fumie Ohnishi
- Department of Pharmacotherapy, Graduate School of Biomedical and Health Sciences, Hiroshima University, 1-2-3 Kasumi, Minami-ku, Hiroshima 734-8551, Japan
| | - Kenichi Todoroki
- Department of Pharmacotherapy, Graduate School of Biomedical and Health Sciences, Hiroshima University, 1-2-3 Kasumi, Minami-ku, Hiroshima 734-8551, Japan
| | - Michiko Yoshii
- Department of Pharmacotherapy, Graduate School of Biomedical and Health Sciences, Hiroshima University, 1-2-3 Kasumi, Minami-ku, Hiroshima 734-8551, Japan
| | - Mai Kakimoto
- Department of Pharmacotherapy, Graduate School of Biomedical and Health Sciences, Hiroshima University, 1-2-3 Kasumi, Minami-ku, Hiroshima 734-8551, Japan
| | - Christa E Müller
- PharmaCenter Bonn, Pharmaceutical Institute, Pharmaceutical Chemistry I, University of Bonn, An der Immenburg 4, D-53121 Bonn, Germany
| | - Koichiro Ozawa
- Department of Pharmacotherapy, Graduate School of Biomedical and Health Sciences, Hiroshima University, 1-2-3 Kasumi, Minami-ku, Hiroshima 734-8551, Japan
| |
Collapse
|
6
|
Shim J, Kennedy RH, Weatherly LM, Hutchinson LM, Pelletier JH, Hashmi HN, Blais K, Velez A, Gosse JA. Arsenic inhibits mast cell degranulation via suppression of early tyrosine phosphorylation events. J Appl Toxicol 2016; 36:1446-59. [PMID: 27018130 DOI: 10.1002/jat.3300] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/03/2015] [Revised: 12/18/2015] [Accepted: 01/05/2016] [Indexed: 12/22/2022]
Abstract
Exposure to arsenic is a global health concern. We previously documented an inhibitory effect of inorganic Arsenite on IgE-mediated degranulation of RBL-2H3 mast cells (Hutchinson et al., 2011; J. Appl. Toxicol. 31: 231-241). Mast cells are tissue-resident cells that are positioned at the host-environment interface, thereby serving vital roles in many physiological processes and disease states, in addition to their well-known roles in allergy and asthma. Upon activation, mast cells secrete several mediators from cytoplasmic granules, in degranulation. The present study is an investigation of Arsenite's molecular target(s) in the degranulation pathway. Here, we report that arsenic does not affect degranulation stimulated by either the Ca(2) (+) ionophore A23187 or thapsigargin, which both bypass early signaling events. Arsenic also does not alter degranulation initiated by another non-IgE-mediated mast cell stimulant, the G-protein activator compound 48/80. However, arsenic inhibits Ca(2) (+) influx into antigen-activated mast cells. These results indicate that the target of arsenic in the degranulation pathway is upstream of the Ca(2) (+) influx. Phospho-Syk and phospho-p85 phosphoinositide 3-kinase enzyme-linked immunosorbent assays data show that arsenic inhibits early phosphorylation events. Taken together, this evidence indicates that the mechanism underlying arsenic inhibition of mast cell degranulation occurs at the early tyrosine phosphorylation steps in the degranulation pathway. Copyright © 2016 John Wiley & Sons, Ltd.
Collapse
Affiliation(s)
- Juyoung Shim
- Department of Molecular and Biomedical Sciences, University of Maine, Orono, Maine, 04469, USA
| | - Rachel H Kennedy
- Department of Molecular and Biomedical Sciences, University of Maine, Orono, Maine, 04469, USA.,Graduate School of Biomedical Science and Engineering, University of Maine, Orono, Maine, 04469, USA
| | - Lisa M Weatherly
- Department of Molecular and Biomedical Sciences, University of Maine, Orono, Maine, 04469, USA.,Graduate School of Biomedical Science and Engineering, University of Maine, Orono, Maine, 04469, USA
| | - Lee M Hutchinson
- Department of Molecular and Biomedical Sciences, University of Maine, Orono, Maine, 04469, USA
| | - Jonathan H Pelletier
- Department of Molecular and Biomedical Sciences, University of Maine, Orono, Maine, 04469, USA
| | - Hina N Hashmi
- Department of Molecular and Biomedical Sciences, University of Maine, Orono, Maine, 04469, USA
| | - Kayla Blais
- Department of Molecular and Biomedical Sciences, University of Maine, Orono, Maine, 04469, USA
| | - Alejandro Velez
- Department of Molecular and Biomedical Sciences, University of Maine, Orono, Maine, 04469, USA
| | - Julie A Gosse
- Department of Molecular and Biomedical Sciences, University of Maine, Orono, Maine, 04469, USA. .,Graduate School of Biomedical Science and Engineering, University of Maine, Orono, Maine, 04469, USA.
| |
Collapse
|
7
|
Falcone FH, Alcocer MJC, Okamoto-Uchida Y, Nakamura R. Use of humanized rat basophilic leukemia reporter cell lines as a diagnostic tool for detection of allergen-specific IgE in allergic patients: time for a reappraisal? Curr Allergy Asthma Rep 2016; 15:67. [PMID: 26452547 DOI: 10.1007/s11882-015-0568-3] [Citation(s) in RCA: 21] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/22/2022]
Abstract
The interaction between allergens and specific IgE is at the heart of the allergic response and as such lies at the center of techniques used for diagnosis of allergic sensitization. Although serological tests are available, in vivo tests such as double-blind placebo-controlled food challenges (DBPCFC) and skin prick test (SPT) associated to the patients' clinical history are still the main guides to clinicians in many practices around the world. More recently, complex protein arrays and basophil activation tests, requiring only small amounts of whole blood, have been developed and refined, but are yet to enter clinical practice. Similarly, the use of rat basophilic leukemia (RBL) cell lines for detection of allergen-specific IgE has been made possible by stable transfection of the human FcεRI α chain into this cell line more than 20 years ago, but has not found widespread acceptance among clinicians. Here, we review the perceived limitations of diagnostic applications of humanized RBL systems. Furthermore, we illustrate how the introduction of reporter genes into humanized RBL cells is able to overcome most of these limitations, and has the potential to become a new powerful tool to complement the armamentarium of allergists. A demonstration of the usefulness of humanized RBL reporter systems for elucidation of complex IgE sensitization patterns against wheat proteins and a section on the use of fluorescence-based reporter systems in combination with allergen arrays close the review.
Collapse
Affiliation(s)
- Franco H Falcone
- Division of Molecular and Cellular Science, School of Pharmacy, University of Nottingham, Boots Science Building, Science Road, NG7 2RD, Nottingham, UK.
| | - Marcos J C Alcocer
- Nutritional Sciences, School of Biosciences, University of Nottingham, Sutton Bonington, LE12 5RD, Nottingham, UK
| | | | | |
Collapse
|
8
|
Borea PA, Varani K, Vincenzi F, Baraldi PG, Tabrizi MA, Merighi S, Gessi S. The A3 adenosine receptor: history and perspectives. Pharmacol Rev 2015; 67:74-102. [PMID: 25387804 DOI: 10.1124/pr.113.008540] [Citation(s) in RCA: 188] [Impact Index Per Article: 20.9] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/06/2023] Open
Abstract
By general consensus, the omnipresent purine nucleoside adenosine is considered a major regulator of local tissue function, especially when energy supply fails to meet cellular energy demand. Adenosine mediation involves activation of a family of four G protein-coupled adenosine receptors (ARs): A(1), A(2)A, A(2)B, and A(3). The A(3) adenosine receptor (A(3)AR) is the only adenosine subtype to be overexpressed in inflammatory and cancer cells, thus making it a potential target for therapy. Originally isolated as an orphan receptor, A(3)AR presented a twofold nature under different pathophysiologic conditions: it appeared to be protective/harmful under ischemic conditions, pro/anti-inflammatory, and pro/antitumoral depending on the systems investigated. Until recently, the greatest and most intriguing challenge has been to understand whether, and in which cases, selective A(3) agonists or antagonists would be the best choice. Today, the choice has been made and A(3)AR agonists are now under clinical development for some disorders including rheumatoid arthritis, psoriasis, glaucoma, and hepatocellular carcinoma. More specifically, the interest and relevance of these new agents derives from clinical data demonstrating that A(3)AR agonists are both effective and safe. Thus, it will become apparent in the present review that purine scientists do seem to be getting closer to their goal: the incorporation of adenosine ligands into drugs with the ability to save lives and improve human health.
Collapse
Affiliation(s)
- Pier Andrea Borea
- Department of Medical Sciences, Pharmacology Section (P.A.B., K.V., F.V., S.M., S.G.), and Department of Pharmaceutical Sciences, University of Ferrara, Italy (P.G.B., M.A.T.)
| | - Katia Varani
- Department of Medical Sciences, Pharmacology Section (P.A.B., K.V., F.V., S.M., S.G.), and Department of Pharmaceutical Sciences, University of Ferrara, Italy (P.G.B., M.A.T.)
| | - Fabrizio Vincenzi
- Department of Medical Sciences, Pharmacology Section (P.A.B., K.V., F.V., S.M., S.G.), and Department of Pharmaceutical Sciences, University of Ferrara, Italy (P.G.B., M.A.T.)
| | - Pier Giovanni Baraldi
- Department of Medical Sciences, Pharmacology Section (P.A.B., K.V., F.V., S.M., S.G.), and Department of Pharmaceutical Sciences, University of Ferrara, Italy (P.G.B., M.A.T.)
| | - Mojgan Aghazadeh Tabrizi
- Department of Medical Sciences, Pharmacology Section (P.A.B., K.V., F.V., S.M., S.G.), and Department of Pharmaceutical Sciences, University of Ferrara, Italy (P.G.B., M.A.T.)
| | - Stefania Merighi
- Department of Medical Sciences, Pharmacology Section (P.A.B., K.V., F.V., S.M., S.G.), and Department of Pharmaceutical Sciences, University of Ferrara, Italy (P.G.B., M.A.T.)
| | - Stefania Gessi
- Department of Medical Sciences, Pharmacology Section (P.A.B., K.V., F.V., S.M., S.G.), and Department of Pharmaceutical Sciences, University of Ferrara, Italy (P.G.B., M.A.T.)
| |
Collapse
|
9
|
Ma HT, Beaven MA. Regulators of Ca(2+) signaling in mast cells: potential targets for treatment of mast cell-related diseases? ADVANCES IN EXPERIMENTAL MEDICINE AND BIOLOGY 2011; 716:62-90. [PMID: 21713652 DOI: 10.1007/978-1-4419-9533-9_5] [Citation(s) in RCA: 65] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Subscribe] [Scholar Register] [Indexed: 12/23/2022]
Abstract
A calcium signal is essential for degranulation, generation of eicosanoids and optimal production of cytokines in mast cells in response to antigen and other stimulants. The signal is initiated by phospholipase C-mediated production of inositol1,4,5-trisphosphate resulting in release of stored Ca(2+) from the endoplasmic reticulum (ER) and Golgi. Depletion of these stores activates influx of extracellular Ca(2+), usually referred to as store-operated calcium entry (SOCE), through the interaction of the Ca(2+)-sensor, stromal interacting molecule-1 (STIM1 ), in ER with Orai1(CRACM1) and transient receptor potential canonical (TRPC) channel proteins in the plasma membrane (PM). This interaction is enabled by microtubular-directed reorganization of ER to form ER/PM contact points or "punctae" in which STIM1 and channel proteins colocalize. The ensuing influx of Ca(2+) replenishes Ca(2+) stores and sustains elevated levels of cytosolic Ca(2+) ions-the obligatory signal for mast-cell activation. In addition, the signal can acquire spatial and dynamic characteristics (e.g., calcium puffs, waves, oscillations) that encode signals for specific functional outputs. This is achieved by coordinated regulation of Ca(2+) fluxes through ATP-dependent Ca(2+)-pumps and ion exchangers in mitochondria, ER and PM. As discussed in this chapter, studies in mast cells revealed much about the mechanisms described above but little about allergic and autoimmune diseases although studies in other types of cells have exposed genetic defects that lead to aberrant calcium signaling in immune diseases. Pharmacologic agents that inhibit or activate the regulatory components of calcium signaling in mast cells are also discussed along with the prospects for development of novel SOCE inhibitors that may prove beneficial in the treatment inflammatory mast-cell related diseases.
Collapse
Affiliation(s)
- Hong-Tao Ma
- Laboratory of Molecular Immunology, National Heart, Lung and Blood Institute, National Institutes of Health, Bethesda, Maryland, USA
| | | |
Collapse
|
10
|
Kuehn HS, Rådinger M, Brown JM, Ali K, Vanhaesebroeck B, Beaven MA, Metcalfe DD, Gilfillan AM. Btk-dependent Rac activation and actin rearrangement following FcepsilonRI aggregation promotes enhanced chemotactic responses of mast cells. J Cell Sci 2010; 123:2576-85. [PMID: 20587594 DOI: 10.1242/jcs.071043] [Citation(s) in RCA: 69] [Impact Index Per Article: 4.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/14/2022] Open
Abstract
Mast cells infiltrate the sites of inflammation associated with chronic atopic disease and during helminth and bacterial infection. This process requires receptor-mediated cell chemotaxis across a concentration gradient of their chemotactic ligands. In vivo, mast cells are likely to be exposed to several such agents, which can cooperate in a synergistic manner to regulate mast cell homing. Here, we report that chemotaxis of mouse bone-marrow-derived mast cells (BMMCs) in response to the chemoattractants stem-cell factor (SCF) and prostaglandin (PG)E(2), is substantially enhanced following antigen-dependent ligation of the high-affinity receptor for IgE (FcεRI). These responses were associated with enhanced activation of phosphoinositide 3-kinase (PI3K), and downstream activation of the tyrosine protein kinase Btk, with subsequent enhanced phospholipase (PL)Cγ-mediated Ca(2+) mobilization, Rac activation and F-actin rearrangement. Antigen-induced chemotaxis, and the ability of antigen to amplify responses mediated by SCF, adenosine and PGE(2) were suppressed following inhibition of PI3K, and were impaired in BMMCs derived from Btk(-/-) mice. There were corresponding decreases in the PLCγ-mediated Ca(2+) signal, Rac activation and F-actin rearrangement, which, as they are essential for BMMC chemotaxis, accounts for the impaired migration of Btk-deficient cells. Taken together, these data demonstrate that, by regulating signaling pathways that control F-actin rearrangement, Btk is crucial for the ability of antigen to amplify mast-cell chemotactic responses.
Collapse
Affiliation(s)
- Hye Sun Kuehn
- Laboratory of Allergic Diseases, National Institute of Allergy and Infectious Diseases, National Institutes of Health, 10 Center Drive MSC 1881, Bethesda, MD 20892-1881, USA
| | | | | | | | | | | | | | | |
Collapse
|
11
|
Lee JH, Kim NW, Her E, Kim BK, Hwang KH, Choi DK, Lim BO, Han JW, Kim YM, Choi WS. Rubiae Radix suppresses the activation of mast cells through the inhibition of Syk kinase for anti-allergic activity. J Pharm Pharmacol 2010; 58:503-12. [PMID: 16597368 DOI: 10.1211/jpp.58.4.0010] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/31/2022]
Abstract
Abstract
The effect of extracts from various Oriental medicinal herbs on mast-cell-mediated allergic reactions was investigated in this study. Of these extracts, the medicinal herb Rubiae Radix exhibited the most potent activity in the cells, with an IC50 value (concentration necessary to obtain 50% inhibition of the response) of approximately 35±2.1 μg mL−1, and its inhibition of compound-48/80-induced systemic anaphylaxis by 48.6±8.5% at 300 mg kg−1 in mice. It also inhibited the expression of the pro-inflammatory mediator tumour necrosis factor-α (TNF-α). As for its mechanism of action, Rubiae Radix suppressed the activating phosphorylation of Syk, a key enzyme in mast-cell signalling processes, and that of Akt in a dose-dependent manner. It also inhibited the MAP kinase ERK1/2, which is critical for the production of inflammatory cytokines in mast cells, as indicated by the suppression of the activating phosphorylation of ERK1/2. These results suggest that Rubiae Radix suppresses the activation of mast cells through the inhibition of Syk for antiallergic activity.
Collapse
Affiliation(s)
- Jun Ho Lee
- College of Medicine and Institute of Biomedical Science and Technology, Konkuk University, Chungju 380-701, Korea
| | | | | | | | | | | | | | | | | | | |
Collapse
|
12
|
Lee JH, Chang SH, Park YS, Her E, Lee HY, Park JW, Han JW, Kim YM, Choi WS. In-vitro and in-vivo anti-allergic actions of Arecae semen. J Pharm Pharmacol 2010; 56:927-33. [PMID: 15233873 DOI: 10.1211/0022357023808] [Citation(s) in RCA: 13] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/31/2022]
Abstract
Abstract
The effects of various extracts from oriental medicinal herbs on mast cell-mediated allergic reactions have been investigated. Among the extracts, Arecae semen was the most potent inhibitor of antigen-induced degranulation in RBL-2H3 mast cells. A. semen inhibited DNP-BSA- and compound 48/80-induced degranulation in RBL-2H3 mast cells with IC50 values of approximately 53 and 52 μg mL−1, respectively, and inhibited compound 48/80-induced systemic anaphylaxis by 46% at 300 mg kg−1 in mice. A. semen also inhibited the expression of TNF-α and the activation of mitogen activated protein kinase, ERK1/2, which is critical for the production of inflammatory cytokines in mast cells, as indicated by the suppression of the activating phosphorylation of ERK1/2. These results suggest that A. semen may be useful for the treatment of various immediate and delayed allergic diseases.
Collapse
Affiliation(s)
- Jun Ho Lee
- Bio-Food and Drug Research Center, Department of Immunology, College of Medicine, Konkuk University, Chungju, 380-701, South Korea
| | | | | | | | | | | | | | | | | |
Collapse
|
13
|
Nunomura S, Gon Y, Yoshimaru T, Kashiwakura J, Kawakami T, Ra C. FcεRI β-chain ITAM amplifies PI3K-signaling to ensure synergistic degranulation responseviaFcεRI and adenosine receptors. Eur J Immunol 2010; 40:1205-17. [DOI: 10.1002/eji.200939651] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/12/2022]
|
14
|
Lim BO, Lee JH, Ko NY, Mun SH, Kim JW, Kim DK, Kim JD, Kim BK, Kim HS, Her E, Lee HY, Choi WS. Polygoni cuspidati radix inhibits the activation of Syk kinase in mast cells for antiallergic activity. Exp Biol Med (Maywood) 2007; 232:1425-31. [PMID: 18040066 DOI: 10.3181/0705-rm-118] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/11/2023] Open
Abstract
The antiallergic activity of Polygoni cuspidati radix (PR) and the mechanism of action by which it functions were investigated in this study. The extract of PR exhibited potent inhibitory activity in mast cells; its IC50 values were 62 +/- 2.1 microg/ml for RBL-2H3 mast cells and 46 +/- 3.2 microg/m for bone marrow-derived mast cells by antigen stimulation, and it also suppressed the expression of tumor necrosis factor-alpha and interleukin-4 in RBL-2H3 cells. According to the in vivo animal allergy model, it inhibited a local allergic reaction, passive cutaneous anaphylaxis, in a dose-dependent manner. With regard to its mechanism of action, PR inhibited the activating phosphorylation of Syk, a key signaling protein for the activation of mast cells. It also suppressed Akt and the mitogen-activated protein kinases ERK1/2, p38, and JNK, which are critical for the production of various inflammatory cytokines in mast cells. The results of the study indicate that the antiallergic activity of PR is mediated through the inhibition of histamine release and allergic cytokine production by the inhibition of Syk activating phosphorylation in mast cells.
Collapse
Affiliation(s)
- Beong Ou Lim
- College of Biomedical & Health Science, Konkuk University, Chungju 380-701, Korea
| | | | | | | | | | | | | | | | | | | | | | | |
Collapse
|
15
|
Ezeamuzie CI, Khan I. The role of adenosine A2 receptors in the regulation of TNF-α production and PGE2 release in mouse peritoneal macrophages. Int Immunopharmacol 2007; 7:483-90. [PMID: 17321471 DOI: 10.1016/j.intimp.2006.12.001] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/23/2006] [Revised: 11/29/2006] [Accepted: 12/04/2006] [Indexed: 11/19/2022]
Abstract
The adenosine A(2) receptors are known to mediate most of the anti-inflammatory activities of adenosine. In lipopolysaccharides (LPS)-stimulated macrophages adenosine strongly inhibits TNF-alpha release, but may also enhance PGE(2) generation. The aims of this study were to determine the relative contributions of the A(2A) and A(2B) receptor subclasses in these two effects and to determine whether the enhanced release of PGE(2) contributes to the inhibition of TNF-alpha release. In LPS-stimulated mouse macrophages, adenosine potently inhibited TNF-alpha production and also potentiated PGE(2) release, though less potently (IC(50)=250 nM vs EC(50) approximately 8 microM, respectively). The non-selective adenosine receptor agonist NECA, and the selective A(2A) receptor agonist CGS21680 also inhibited TNF-alpha production even more potently (IC(50)=4.8 and 2.3 nM, respectively). NECA, but not CGS21680, also enhanced PGE(2) production. The selective A(2A) receptor antagonist ZM241385 (30 nM), but not the selective A(2B) receptor antagonist MRS1754 (30 nM), blocked the inhibitory effect of NECA and CGS21680 on TNF-alpha release. On the other hand, MRS1754, but not ZM241385, abolished the PGE(2) potentiating effect of NECA. Pre-treatment with indomethacin (1 microM) abolished adenosine-induced PGE(2) release enhancement but did not prevent the inhibition of TNF-alpha release. These results show that in this system, the inhibition of TNF-alpha release by adenosine is mediated by the A(2A) receptors whereas the enhancement of PGE(2) release appears to be mediated by the A(2B) receptors. The results also show that while exogenous PGE(2) is a potent inhibitor of TNF-alpha release, the enhanced PGE(2) release induced by adenosine does not appear to contribute to the inhibition of TNF-alpha release.
Collapse
Affiliation(s)
- C I Ezeamuzie
- Department of Pharmacology, Faculty of Medicine, Kuwait University, Kuwait
| | | |
Collapse
|
16
|
Lee JH, Ko NY, Kim NW, Mun SH, Kim JW, Her E, Kim BK, Seo DW, Chang HW, Moon TC, Han JW, Kim YM, Choi WS. Meliae cortex extract exhibits anti-allergic activity through the inhibition of Syk kinase in mast cells. Toxicol Appl Pharmacol 2007; 220:227-34. [PMID: 17395225 DOI: 10.1016/j.taap.2006.10.034] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/08/2006] [Revised: 10/19/2006] [Accepted: 10/20/2006] [Indexed: 11/18/2022]
Abstract
The anti-allergic action of various Oriental medicinal herbs was investigated using in vitro and in vivo experimental models. Of these extracts, the ethanol extract of Meliae cortex (MC) exhibited the most potent activity in mast cells; its IC(50) values were 29+/-1.5 microg/ml for antigen stimulation and 57+/-3.4 microg/ml for thapsigargin stimulation. It inhibited compound-48/80-induced systemic anaphylaxis by 52.9% at a dose of 300 mg/kg in mice; it also inhibited the expression of the proinflammatory mediator TNF-alpha. With regard to its mechanism of action, MC suppressed the activating phosphorylation of Syk, a key enzyme in mast-cell signaling processes and that of Akt in a dose-dependent manner. It also inhibited the MAP kinase ERK1/2, which is critical for the production of inflammatory cytokines in mast cells, as indicated by the suppression of the activating phosphorylation of ERK1/2. Taken together, these results suggest that the anti-allergic activity of MC may be due to the inhibition of histamine secretion and cytokine expression through the Syk inhibition in mast cells.
Collapse
Affiliation(s)
- Jun Ho Lee
- College of Medicine, Konkuk University, Chungju 380-701, South Korea
| | | | | | | | | | | | | | | | | | | | | | | | | |
Collapse
|
17
|
Vennekens R, Olausson J, Meissner M, Bloch W, Mathar I, Philipp SE, Schmitz F, Weissgerber P, Nilius B, Flockerzi V, Freichel M. Increased IgE-dependent mast cell activation and anaphylactic responses in mice lacking the calcium-activated nonselective cation channel TRPM4. Nat Immunol 2007; 8:312-20. [PMID: 17293867 DOI: 10.1038/ni1441] [Citation(s) in RCA: 201] [Impact Index Per Article: 11.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/06/2006] [Accepted: 01/16/2007] [Indexed: 11/08/2022]
Abstract
Mast cells are key effector cells in allergic reactions. Aggregation of the receptor FcepsilonRI in mast cells triggers the influx of calcium (Ca(2+)) and the release of inflammatory mediators. Here we show that transient receptor potential TRPM4 proteins acted as calcium-activated nonselective cation channels and critically determined the driving force for Ca(2+) influx in mast cells. Trpm4(-/-) bone marrow-derived mast cells had more Ca(2+) entry than did TRPM4(+/+) cells after FcepsilonRI stimulation. Consequently, Trpm4(-/-) bone marrow-derived mast cells had augmented degranulation and released more histamine, leukotrienes and tumor necrosis factor. Trpm4(-/-) mice had a more severe IgE-mediated acute passive cutaneous anaphylactic response, whereas late-phase passive cutaneous anaphylaxis was not affected. Our results establish the physiological function of TRPM4 channels as critical regulators of Ca(2+) entry in mast cells.
Collapse
Affiliation(s)
- Rudi Vennekens
- Laboratory of Ion Channel Research, Division of Physiology, Department of Molecular Cell Biology, Campus Gasthuisberg, O&N1, KU Leuven, Herestraat 49 bus 802, B-3000 Leuven, Belgium.
| | | | | | | | | | | | | | | | | | | | | |
Collapse
|
18
|
Palmer TM, Stiles GL. The new biology of adenosine receptors. ADVANCES IN ENZYMOLOGY AND RELATED AREAS OF MOLECULAR BIOLOGY 2006; 69:83-120. [PMID: 7817871 DOI: 10.1002/9780470123157.ch3] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/27/2023]
Affiliation(s)
- T M Palmer
- Department of Medicine, Duke University Medical Center, Durham, NC
| | | |
Collapse
|
19
|
Lee JH, Kim YM, Kim NW, Kim JW, Her E, Kim BK, Kim JH, Ryu SH, Park JW, Seo DW, Han JW, Beaven MA, Choi WS. Phospholipase D2 acts as an essential adaptor protein in the activation of Syk in antigen-stimulated mast cells. Blood 2006; 108:956-64. [PMID: 16861349 PMCID: PMC1895856 DOI: 10.1182/blood-2005-10-009159] [Citation(s) in RCA: 22] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/11/2023] Open
Abstract
Mast cells are responsible for IgE-mediated allergic reactions. Phospholipase D1 (PLD1) and PLD2 regulate mast cell activation, but the mechanisms remain unclear. Here we show that PLD2 associates with and promotes activation of Syk, a key enzyme in mast cell activation. Antigen stimulation resulted in increased association and colocalization of Syk with PLD2 on the plasma membrane as indicated by coimmunoprecipitation and confocal microscopy. This association was dependent on tyrosine phosphorylation of Syk but not on PLD2 activity. In vitro, PLD2 interacted via its Phox homology (PX) domain with recombinant Syk to induce phosphorylation and activation of Syk. Furthermore, overexpression of PLD2 or catalytically inactive PLD2K758R enhanced antigen-induced phosphorylations of Syk and its downstream targets, the adaptor proteins LAT and SLP-76, while expression of a PLD2 siRNA blocked these phosphorylations. Apparently, the interaction of PLD2 with Syk is an early critical event in the activation of mast cells.
Collapse
Affiliation(s)
- Jun Ho Lee
- Department of Immunology, College of Medicine, Konkuk University, Chungju 380-701, Korea
| | | | | | | | | | | | | | | | | | | | | | | | | |
Collapse
|
20
|
Guinzberg R, Uribe S, Díaz-Cruz A, Hernández Cruz A, Piña E. In rat hepatocytes, different adenosine receptor subtypes use different secondary messengers to increase the rate of ureagenesis. Life Sci 2006; 79:382-90. [PMID: 16494901 DOI: 10.1016/j.lfs.2006.01.021] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/26/2005] [Revised: 12/01/2005] [Accepted: 01/12/2006] [Indexed: 11/24/2022]
Abstract
In rat hepatocytes, the role of cAMP and Ca(2+) as secondary messengers in the ureagenic response to stimulation of specific adenosine receptor subtypes was explored. Analyzed receptor subtypes were: A(1), A(2A), A(2B) and A(3). Each receptor subtype was stimulated with a specific agonist while blocking all other receptor subtypes with a battery of specific antagonists. For the A(1) and A(3) adenosine receptor subtypes, the secondary messenger was the cytoplasmic Ca(2+) concentration ([Ca(2+)](cyt)). Accordingly, the A(1) or A(3)-mediated increase in [Ca(2+)](cyt) and in ureagenic activity were both inhibited by chelating Ca(2+) with either EGTA or BAPTA-AM. Also, Gd(3+) blocked both the increase in [Ca(2+)](cyt) and ureagenesis, suggesting that a Ca(2+) channel may be involved in the response to both A(1) and A(3). A partial effect was observed with the sarcoplasmic reticulum Ca(2+)-ATPase inhibitor thapsigargin. The concentration of cyclic AMP ([cAMP]) increased in response to stimulation of either the A(2A) or the A(2B) adenosine receptor subtypes, while it decreased slightly in response to stimulation of either A(1) or A(3). The stimulation of either the A(2A) or A(2B) adenosine receptor subtypes resulted in an increase in [cAMP] and an ureagenic response which were not sensitive to EGTA, BAPTA-AM, Gd(3+) or to thapsigargin. In addition, the adenylyl cyclase inhibitor MDL12,330A blocked the ureagenic response to A(2A) and A(2B), but not the response to either A(1) or A(3). Our results indicate that in the ureagenic liver response to adenosine, the secondary messenger for both, the A(1) and A(3) adenosine receptor subtypes is [Ca(2+)](cyt), while the message from the A(2A) and A(2B) adenosine receptor subtypes is relayed by [cAMP].
Collapse
Affiliation(s)
- Raquel Guinzberg
- Department of Biochemistry, School of Medicine, National Autonomous University of México, Apdo Postal 70-159, México D.F., 04510, Mexico
| | | | | | | | | |
Collapse
|
21
|
Shanley TP, Bshesh K. Therapeutic targeting of adenosine receptors in inflammatory diseases. ACTA ACUST UNITED AC 2005. [DOI: 10.1517/14728222.4.4.447] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/05/2022]
|
22
|
Lee JH, Seo JY, Ko NY, Chang SH, Her E, Park T, Lee HY, Han JW, Kim YM, Choi WS. Inhibitory activity of Chrysanthemi sibirici herba extract on RBL-2H3 mast cells and compound 48/80-induced anaphylaxis. JOURNAL OF ETHNOPHARMACOLOGY 2004; 95:425-430. [PMID: 15507370 DOI: 10.1016/j.jep.2004.08.023] [Citation(s) in RCA: 17] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/30/2004] [Revised: 08/23/2004] [Accepted: 08/23/2004] [Indexed: 05/24/2023]
Abstract
The effects of extracts from various oriental medicinal herbs on mast cell-mediated allergic reaction were investigated. Among them, Chrysanthemi sibirici herba ethanol extract exerted the potent inhibitory activity on antigen-induced degranulation in RBL-2H3 mast cells. Chrysanthemi sibirici herba dose-dependently inhibited DNP-BSA or compound 48/80-induced degranulation in RBL-2H3 mast cells, with IC(50) values of approximately 49 microg/ml and 76 microg/ml, respectively. This extract strongly suppressed compound 48/80-induced systemic anaphylaxis by 48.7% at a dose of 300 mg/kg in mice. Chrysanthemi sibirici herba also inhibited the expression of TNF-alpha and the activation of the MAP kinase, ERK1/2, which is critical for the production of inflammatory cytokines in mast cells, as indicated by the suppression of activating phosphorylation of ERK1/2. These results lead us to conclude that Chrysanthemi sibirici herba may be used clinically to treat various allergic diseases.
Collapse
Affiliation(s)
- Jun Ho Lee
- Department of Immunology, College of Medicine, Konkuk University, Chungju 380-701, Republic of Korea
| | | | | | | | | | | | | | | | | | | |
Collapse
|
23
|
Choi WS, Hiragun T, Lee JH, Kim YM, Kim HP, Chahdi A, Her E, Han JW, Beaven MA. Activation of RBL-2H3 mast cells is dependent on tyrosine phosphorylation of phospholipase D2 by Fyn and Fgr. Mol Cell Biol 2004; 24:6980-92. [PMID: 15282299 PMCID: PMC479740 DOI: 10.1128/mcb.24.16.6980-6992.2004] [Citation(s) in RCA: 37] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/18/2022] Open
Abstract
Both phospholipase D1 (PLD1) and PLD2 regulate degranulation when RBL-2H3 cells are stimulated via the immunoglobulin E receptor, Fc epsilon RI. However, the activation mechanism for PLD2 is unclear. As reported here, PLD2 but not PLD1 is phosphorylated through the Src kinases, Fyn and Fgr, and this phosphorylation appears to regulate PLD2 activation and degranulation. For example, only hemagglutinin-tagged PLD2 was tyrosine phosphorylated in antigen-stimulated cells that had been made to express HA-PLD1 and HA-PLD2. This phosphorylation was blocked by a Src kinase inhibitor or by small interfering RNAs directed against Fyn and Fgr and was enhanced by overexpression of Fyn and Fgr but not by other Src kinases. The phosphorylation and activity of PLD2 were further enhanced by the tyrosine phosphatase inhibitor, Na(3)VO(4). Mutation of PLD2 at tyrosines 11, 14, 165, or 470 partially impaired, and mutation of all tyrosines blocked, PLD2 phosphorylation and activation, although two of these mutations were detrimental to PLD2 function. PLD2 phosphorylation preceded degranulation, both events were equally sensitive to inhibition of Src kinase activity, and both were enhanced by coexpression of PLD2 and the Src kinases. The findings provide the first description of a mechanism for activation of PLD2 in a physiological setting and of a role for Fgr in Fc epsilon RI-mediated signaling.
Collapse
Affiliation(s)
- Wahn Soo Choi
- Laboratory of Molecular Immunology, National, Heart, Lung, and Blood Institute, National Institutes of Health, Department of Health and Human Services, Bethesda, Maryland 20892, USA.
| | | | | | | | | | | | | | | | | |
Collapse
|
24
|
Andrade MVM, Hiragun T, Beaven MA. Dexamethasone Suppresses Antigen-Induced Activation of Phosphatidylinositol 3-Kinase and Downstream Responses in Mast Cells. THE JOURNAL OF IMMUNOLOGY 2004; 172:7254-62. [PMID: 15187100 DOI: 10.4049/jimmunol.172.12.7254] [Citation(s) in RCA: 62] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/19/2022]
Abstract
Dexamethasone and other glucocorticoids suppress FcepsilonRI-mediated release of inflammatory mediators from mast cells. Suppression of cytokine production is attributed to repression of cytokine gene transcription but no mechanism has been described for the suppression of degranulation. We show that therapeutic concentrations of dexamethasone inhibit intermediate signaling events, in particular the activation of phosphatidylinositol (PI)3-kinase and downstream signaling events that lead to degranulation in rat basophilic leukemia 2H3 cells. This inhibitory action is mediated via the glucocorticoid receptor and is not apparent when cells are stimulated via Kit in a mouse bone marrow-derived mast cell line. The primary perturbation appears to be the failure of the regulatory p85 subunit of PI3-kinase to engage with the adaptor protein Grb2-associated binder 2 leading to suppression of phosphorylation of phospholipase Cgamma2, the calcium signal, and degranulation. Suppression of PI3-kinase activation by dexamethasone may also contribute to reduced cytokine production because the PI3-kinase inhibitor LY294002, like dexamethasone, inhibits Ag-induced transcription of cytokine genes as well as degranulation.
Collapse
Affiliation(s)
- Marcus V M Andrade
- Laboratory of Molecular Immunology, National Heart, Lung, and Blood Institute, National Institutes of Health, Bethesda, MD 20892, USA
| | | | | |
Collapse
|
25
|
Yaar R, Jones MR, Chen JF, Ravid K. Animal models for the study of adenosine receptor function. J Cell Physiol 2004; 202:9-20. [PMID: 15389588 DOI: 10.1002/jcp.20138] [Citation(s) in RCA: 109] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
Abstract
Adenosine receptors represent a family of G-protein coupled receptors that are ubiquitously expressed in a wide variety of tissues. This family contains four receptor subtypes: A1 and A3, which mediate inhibition of adenylyl cyclase; and A2a and A2b, which mediate stimulation of this enzyme. Currently, all receptor subtypes have been genetically deleted in mouse models except for the A2b adenosine receptor, and some have been overexpressed in selective tissues of transgenic mice. Studies involving these transgenic mice indicated that receptor levels are rate limiting, as effects were amplified upon increases in receptor level. The knockout models pointed to clusters of activities related to the physiologies of the cardiovascular and the nervous systems, which are either reduced or enhanced upon specific receptor deletion. Interestingly, the trend of effects on these systems is similar in the A1 and A3 adenosine receptor knockout mice and opposite to the effects observed in the A2a adenosine receptor knockout model. This review summarizes in vitro studies on pathways affected by each adenosine receptor, and primarily focuses on the above in vivo models generated to investigate the physiologic role of adenosine receptors. Furthermore, it illustrates the need for multiple adenosine receptor subtype deficiency studies in mice and the deletion of the A2b subtype.
Collapse
Affiliation(s)
- R Yaar
- Department of Biochemistry, Whitaker Cardiovascular Institute, Boston University School of Medicine, Boston, Massachusetts, USA
| | | | | | | |
Collapse
|
26
|
Abstract
Evidence is emerging that a quasisynaptic local communication facilitates the calcium signaling between endoplasmic reticulum and mitochondria. However, it remains elusive whether the machinery of mitochondrial calcium signaling displays plasticity similar to the synaptic transmission. Here we studied the relationship between inositol 1,4,5-trisphosphate (IP3)-linked cytosolic [Ca2+] ([Ca2+]c) oscillations and the associated rise in mitochondrial matrix [Ca2+] ([Ca2+]m) in RBL-2H3 mast cells. We observed that the second [Ca2+]c spike is often associated with a larger rise in the [Ca2+]m than the first. It would appear that this phenomenon was not due to a change in the driving force for Ca2+ uptake and therefore must be due to an enhanced Ca2+ permeability of the mitochondrial Ca2+ uptake sites (uniporter). To investigate the activation and deactivation kinetics of the uniporter during IP3 receptor-mediated Ca2+ mobilization, we established novel methods. Using these approaches, we demonstrated that the IP3-induced increase in the permeability of the uniporter lasted longer than the Ca2+ signal. The sustained increase in Ca2+ permeability was bidirectional. Furthermore, the addition of Ca2+ during the decay of the IP3 effect evoked a large further increase in the uniporter permeability. Calmodulin inhibitors did not interfere with the IP3-induced initial activation of the uniporter but inhibited the sustained phase. These results suggest that the uniporter displays a calmodulin-mediated facilitation. This plasticity may allow cooperation among sequential IP3 receptor-mediated [Ca2+] transients in the control of calcium signal propagation to the mitochondria.
Collapse
Affiliation(s)
- György Csordás
- Department of Pathology, Anatomy, and Cell Biology, Thomas Jefferson University, Philadelphia, PA 19107, USA
| | | |
Collapse
|
27
|
Abstract
The purine nucleoside adenosine acts via four distinct adenosine receptor subtypes: the adenosine A(1), A(2A), A(2B), and A(3) receptor. They are all G protein-coupled receptors (GPCR) coupling to classical second messenger pathways such as modulation of cAMP production or the phospholipase C (PLC) pathway. In addition, they couple to mitogen-activated protein kinases (MAPK), which could give them a role in cell growth, survival, death and differentiation. Although each of the adenosine receptors can activate one or more of the MAPKs, the mechanisms appear to differ substantially, both between receptor subtypes in the same cell type and between the same receptor in different cell types.
Collapse
Affiliation(s)
- Gunnar Schulte
- Department of Physiology and Pharmacology, Karolinska Institutet, S-171 77, Stockholm, Sweden.
| | | |
Collapse
|
28
|
Palmer TM, Ferguson G, Watterson KR. Dissecting the regulatory mechanisms controlling inhibitory adenosine receptor signaling. Drug Dev Res 2003. [DOI: 10.1002/ddr.10185] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/07/2022]
|
29
|
Chahdi A, Choi WS, Kim YM, Beaven MA. Mastoparan selectively activates phospholipase D2 in cell membranes. J Biol Chem 2003; 278:12039-45. [PMID: 12556526 DOI: 10.1074/jbc.m212084200] [Citation(s) in RCA: 30] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
Both known isoforms of phospholipase (PL) D, PLD1 and PLD2, require phosphatidylinositol 4,5-bisphosphate for activity. However, PLD2 is fully active in the presence of this phospholipid, whereas PLD1 activation is dependent on additional factors such as ADP-ribosylation factor-1 (ARF-1) and protein kinase Calpha. We find that mastoparan, an activator of G(i) and mast cells, stimulates an intrinsic PLD activity, most likely PLD2, in fractions enriched in plasma membranes from rat basophilic leukemia 2H3 mast cells. Overexpression of PLD2, but not of PLD1, results in a large increase in the mastoparan-inducible PLD activity in membrane fractions, particularly those enriched in plasma membranes. As in previous studies, expressed PLD2 is localized primarily in the plasma membrane and PLD1 in granule membranes. Studies with pertussis toxin and other agents indicate that mastoparan stimulates PLD2 independently of G(i), ARF-1, protein kinase C, and calcium. Kinetic studies indicate that mastoparan interacts synergistically with phosphatidylinositol 4,5-bisphosphate and that oleate, itself a weak stimulant of PLD2 at low concentrations, is a competitive inhibitor of mastoparan stimulation of PLD2. Therefore, mastoparan may be useful for investigating the regulation of PLD2, particularly in view of the well studied molecular interactions of mastoparan with certain other strategic signaling proteins.
Collapse
Affiliation(s)
- Ahmed Chahdi
- Laboratory of Molecular Immunology, NHLBI, National Institutes of Health, Bethesda, Maryland 20892-1760, USA
| | | | | | | |
Collapse
|
30
|
Ezeamuzie CI, Philips E. Positive coupling of atypical adenosine A3 receptors on human eosinophils to adenylyl cyclase. Biochem Biophys Res Commun 2003; 300:712-8. [PMID: 12507508 DOI: 10.1016/s0006-291x(02)02910-8] [Citation(s) in RCA: 18] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/25/2022]
Abstract
Adenosine A(3) receptors are reported to couple negatively to adenylyl cyclase (AC) but their mediation of anti-inflammatory effects in human eosinophils prompted us to investigate their coupling to AC. The A(3)-selective agonists IB-MECA and Cl-IB-MECA evoked a concentration-dependent generation of cAMP (EC(50), 3.2 and 1.8 microM, respectively) and were more potent than the A(2A) agonist CGS 21680 (EC(50)=15.4 microM) and adenosine (EC(50)=19.2 microM). The cAMP response was additive to that produced by forskolin (10 microM). The effect of IB-MECA was insensitive to A(1) and A(2A) receptor antagonists, but was antagonized by the A(3)-selective antagonist MRS 1220 (0.1-2.5 microM) in a competitive manner. The estimated K(B) of 190 nM was, however, atypical. The cyclo-oxygenase inhibitor, indomethacin, had no effect on the cAMP response. A general inverse relationship between cAMP generation and inhibition of degranulation was seen. We conclude that in human eosinophils, an atypical form of A(3) receptors positively coupled to AC may exist. The resulting cAMP generation may underlie the anti-inflammatory actions of A(3) agonists in eosinophils.
Collapse
Affiliation(s)
- Charles I Ezeamuzie
- Department of Pharmacology and Toxicology, Faculty of Medicine, Kuwait University, P.O. Box 24923, Safat 13110, Kuwait.
| | | |
Collapse
|
31
|
Trincavelli ML, Tuscano D, Marroni M, Falleni A, Gremigni V, Ceruti S, Abbracchio MP, Jacobson KA, Cattabeni F, Martini C. A3 adenosine receptors in human astrocytoma cells: agonist-mediated desensitization, internalization, and down-regulation. Mol Pharmacol 2002; 62:1373-84. [PMID: 12435805 PMCID: PMC4806643 DOI: 10.1124/mol.62.6.1373] [Citation(s) in RCA: 62] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022] Open
Abstract
A(3) adenosine receptor activation has been previously demonstrated to result in both neuroprotective and neurodegenerative effects, depending upon specific pathophysiological conditions. This dual effect may depend on receptor regulation mechanisms that are able to change receptor availability and/or function. In the present study, we investigated desensitization, internalization, and down-regulation of native A(3) adenosine receptors in human astrocytoma cells after exposure to the agonist 2-chloro-N6-(3-iodobenzyl)-N-methyl-5'-carbamoyladenosine (Cl-IBMECA). Cl-IBMECA induced a concentration-dependent inhibition of adenylyl cyclase activity with an EC(50) value of 2.9 +/- 0.1 nM. The effect was suggested to be mediated by A(3) adenosine receptor subtype by the use of selective adenosine receptor antagonists. Cell treatment with pertussis toxin abolished Cl-IBMECA-mediated inhibition of adenylyl cyclase activity, evidencing an A(3) receptor coupling to inhibitory G protein. Short-term exposure to the agonist Cl-IBMECA (100 nM) caused rapid receptor desensitization, within 15 min. Agonist-induced desensitization was accompanied by receptor internalization: A(3) adenosine receptor internalized with rapid kinetics, within 30 min, after cell exposure to 100 nM Cl-IBMECA. The localization of A(3) adenosine receptors on the plasma membrane and in intracellular compartments was directly revealed by immunogold electron microscopy. After desensitization, the removal of agonist led to the restoration of A(3) adenosine receptor functioning through receptor recycling to the cell surface within 120 min. Prolonged agonist exposure (1-24 h) resulted in a marked down-regulation of A(3) adenosine receptors that reached 21.9 +/- 2.88% of control value after 24 h. After down-regulation, the recovery of receptor functioning was slow (24 h) and associated with the restoration of receptor levels close to control values. In conclusion, our results demonstrated that A(3) receptors, in astrocytoma cells, are regulated after short- and long-term agonist exposure.
Collapse
Affiliation(s)
- M L Trincavelli
- Dipartimento di Psichiatria, Neurobiologia, Farmacologia e Biotecnologie, Universitá Pisa, Pisa, Italy
| | | | | | | | | | | | | | | | | | | |
Collapse
|
32
|
Schulte G, Fredholm BB. Signaling pathway from the human adenosine A(3) receptor expressed in Chinese hamster ovary cells to the extracellular signal-regulated kinase 1/2. Mol Pharmacol 2002; 62:1137-46. [PMID: 12391277 DOI: 10.1124/mol.62.5.1137] [Citation(s) in RCA: 63] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022] Open
Abstract
Adenosine activates four different receptors, the A(1), A(2A), A(2B), and the A(3) receptors, all of which are G protein-coupled. We have previously shown that stimulation of the human adenosine A(3) receptor can induce phosphorylation of extracellular signal-regulated kinase (ERK1/2). Here we show that the adenosine receptor agonist 5' N-ethylcarboxamidoadenosine (NECA) induces phosphorylation and activation of ERK1/2 in Chinese hamster ovary (CHO) cells expressing the human adenosine A(3) receptor (CHO A(3) cells) with the same potency. Pretreatment with pertussis toxin abolished the effect, which also could be blunted by overexpressing the betagamma-sequestering peptide beta-adrenergic receptor kinase-ct, implicating the involvement of betagamma subunits released from G(i/o) proteins. Activation of phosphatidylinositol-3-kinase (PI3K) by adenosine A(3) receptors is inferred from a dose-dependent Ser-phosphorylation of the protein kinase B (Akt). Furthermore the ERK1/2 phosphorylation was sensitive to the PI3K inhibitors wortmannin and LY294002 (2-(4-morpholinyl)-8-phenyl-1(4H)-benzopyran-4-one hydrochloride) and the MEK inhibitor PD98059 (2'-amino-3'-methoxyflavone), whereas chelation of Ca(2+) with 1,2-bis(2-aminophenoxy)ethane-N,N,N',N'-tetraacetic acid tetrakis (acetoxymethyl ester) and long-term treatment with phorboldibutyrate did not decrease the adenosine A(3) receptor-mediated ERK1/2 phosphorylation. Thus, Ca(2+) mobilization and conventional and novel protein kinase C (PKC) isoforms are not involved in this pathway. The atypical PKCzeta was not activated by NECA and thus not involved in the A(3) receptor-mediated ERK1/2 phosphorylation. NECA stimulation of CHO A(3) cells activated the small G protein Ras and the dominant negative mutant RasS17N prevented the phosphorylation of ERK1/2. In conclusion, the adenosine A(3) receptor recruits a pathway that involves betagamma release from G(i/o), PI3K, Ras, and MEK to induce ERK1/2 phosphorylation and activation, whereas signaling is independent of Ca(2+), PKC, and c-Src.
Collapse
Affiliation(s)
- Gunnar Schulte
- Section of Molecular Neuropharmacology, Department of Physiology & Pharmacology, Karolinska Institutet, Stockholm, Sweden.
| | | |
Collapse
|
33
|
Choi WS, Chahdi A, Kim YM, Fraundorfer PF, Beaven MA. Regulation of phospholipase D and secretion in mast cells by protein kinase A and other protein kinases. Ann N Y Acad Sci 2002; 968:198-212. [PMID: 12119277 DOI: 10.1111/j.1749-6632.2002.tb04336.x] [Citation(s) in RCA: 25] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
Functions attributed to phospholipase (PL) D include the regulation of intracellular trafficking of Golgi-derived vesicles and secretion of granules from mast cells. We have reported that activation of PLD and secretion in a rat mast cell (RBL-2H3) line is substantially enhanced by cholera toxin, a known activator of protein kinase (PK) A. Here we review the evidence that (1) the synergistic interactions of cholera toxin and other pharmacological agents on mast cell secretion are attributable to the synergistic activation of PLD via PKA, CaM kinase II, and PKC and (2) both PLD1 and PLD2 participate in this process. For example, treatment with cholera toxin, thapsigargin, and phorbol 12-myristate 13-acetate (which activate PKA, CaM kinase II, and PKC, respectively) exhibit synergy in the stimulation of both PLD and secretion. These kinases and PLD are likely confined to membrane components, as similar synergistic interactions could be demonstrated in permeabilized cells. The regulation of PLD and secretion by these kinases is also apparent from studies of inhibitors of PKA and other kinases. Also, by overexpression of either PLD1 or PLD2 it is apparent that both isoforms respond to the same stimuli as endogenous PLD, although PLD1 is largely associated with secretory granules and PLD2 with plasma membrane. The studies reveal interesting differences in the regulation of the translocation of granules (regulated by PKA) and the fusion of these granules with the plasma membrane (regulated by Ca(2+) and PKC). The pathological/physiological implications of the regulation of PLD by PKA require further evaluation in other cell systems.
Collapse
Affiliation(s)
- Wahn Soo Choi
- Laboratory of Molecular Immunology, National Heart, Lung, and Blood Institute, National Institutes of Health, Bethesda, Maryland 20892-1760, USA
| | | | | | | | | |
Collapse
|
34
|
Choi WS, Kim YM, Combs C, Frohman MA, Beaven MA. Phospholipases D1 and D2 regulate different phases of exocytosis in mast cells. JOURNAL OF IMMUNOLOGY (BALTIMORE, MD. : 1950) 2002; 168:5682-9. [PMID: 12023367 DOI: 10.4049/jimmunol.168.11.5682] [Citation(s) in RCA: 103] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/19/2022]
Abstract
The rat mast cell line RBL-2H3 contains both phospholipase D (PLD)1 and PLD2. Previous studies with this cell line indicated that expressed PLD1 and PLD2 are both strongly activated by stimulants of secretion. We now show by use of PLDs tagged with enhanced green fluorescent protein that PLD1, which is largely associated with secretory granules, redistributes to the plasma membrane in stimulated cells by processes reminiscent of exocytosis and fusion of granules with the plasma membrane. These processes and secretion of granules are suppressed by expression of a catalytically inactive mutant of PLD1 or by the presence of 50 mM 1-butanol but not tert-butanol, an indication that these events are dependent on the catalytic activity of PLD1. Of note, cholera toxin induces translocation of PLD1-labeled granules to the plasma membrane but not fusion of granules with plasma membrane or secretion. Subsequent stimulation of calcium influx with Ag or thapsigargin leads to rapid redistribution of PLD1 to the plasma membrane and accelerated secretion. Also of note, PLD1 is recycled from plasma membrane back to granules within 4 h of stimulation. PLD2, in contrast, is largely confined to the plasma membrane, but it too participates in the secretory process, because expression of catalytically inactive PLD2 also blocks secretion. These data indicate a two-step process: translocation of granules to the cell periphery, regulated by granule-associated PLD1, and a calcium-dependent fusion of granules with the plasma membrane, regulated by plasma membrane-associated PLD2 and possibly PLD1.
Collapse
Affiliation(s)
- Wahn Soo Choi
- Laboratory of Molecular Immunology and Light Microscopy Core Facility, National Heart Lung and Blood Institute, National Institutes of Health, Bethesda, MD 20892, USA
| | | | | | | | | |
Collapse
|
35
|
Kim SG, Ravi G, Hoffmann C, Jung YJ, Kim M, Chen A, Jacobson KA. p53-Independent induction of Fas and apoptosis in leukemic cells by an adenosine derivative, Cl-IB-MECA. Biochem Pharmacol 2002; 63:871-80. [PMID: 11911839 PMCID: PMC4811183 DOI: 10.1016/s0006-2952(02)00839-0] [Citation(s) in RCA: 51] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/26/2022]
Abstract
A(3) adenosine receptor (A(3)AR) agonists have been reported to influence cell death and survival. The effects of an A(3)AR agonist, 1-[2-chloro-6-[[(3-iodophenyl)methyl]amino]-9H-purin-9-yl]-1-deoxy-N-methyl-beta-D-ribofuranonamide (Cl-IB-MECA), on apoptosis in two human leukemia cell lines, HL-60 and MOLT-4, were investigated. Cl-IB-MECA (> or =30 microM) increased the apoptotic fractions, as determined using fluorescence-activated cell sorting (FACS) analysis, and activated caspase 3 and poly-ADP-ribose-polymerase. Known messengers coupled to A(3)AR (phospholipase C and intracellular calcium) did not seem to play a role in the induction of apoptosis. Neither dantrolene nor BAPTA-AM affected the Cl-IB-MECA-induced apoptosis. Cl-IB-MECA failed to activate phospholipase C in HL-60 cells, while UTP activated it through endogenous P2Y(2) receptors. Induction of apoptosis during a 48hr exposure to Cl-IB-MECA was not prevented by the A(3)AR antagonists [5-propyl-2-ethyl-4-propyl-3-(ethylsulfanylcarbonyl)-6-phenylpyridine-5-carboxylate] (MRS 1220) or N-[9-chloro-2-(2-furanyl)[1,2,4]triazolo[1,5-c]quinazolin-5-yl]benzeneacetamide (MRS 1523). Furthermore, higher concentrations of MRS 1220, which would also antagonize A(1) and A(2A) receptors, were ineffective in preventing the apoptosis. Although Cl-IB-MECA has been shown in other systems to cause apoptosis through an A(3)AR-mediated mechanism, in these cells it appeared to be an adenosine receptor-independent effect, which required prolonged incubation. In both HL-60 and MOLT-4 cells, Cl-IB-MECA induced the expression of Fas, a death receptor. This induction of Fas was not dependent upon p53, because p53 is not expressed in an active form in either HL-60 or MOLT-4 cells. Cl-IB-MECA-induced apoptosis in HL-60 cells was augmented by an agonistic Fas antibody, CH-11, and this increase was suppressed by the antagonistic anti-Fas antibody ZB-4. Therefore, Cl-IB-MECA induced apoptosis via a novel, p53-independent up-regulation of Fas.
Collapse
Affiliation(s)
- Seong Gon Kim
- Molecular Recognition Section, Laboratory of Bioorganic Chemistry, National Institute of Diabetes, Digestive and Kidney Diseases, National Institutes of Health, Building 8A, Room B1A-19, Bethesda, MD 20892, USA
| | - Gnana Ravi
- Molecular Recognition Section, Laboratory of Bioorganic Chemistry, National Institute of Diabetes, Digestive and Kidney Diseases, National Institutes of Health, Building 8A, Room B1A-19, Bethesda, MD 20892, USA
| | - Carsten Hoffmann
- Molecular Recognition Section, Laboratory of Bioorganic Chemistry, National Institute of Diabetes, Digestive and Kidney Diseases, National Institutes of Health, Building 8A, Room B1A-19, Bethesda, MD 20892, USA
| | - Yun-Jin Jung
- Medicine Branch, National Cancer Institute, National Institutes of Health, Bethesda, MD 20892, USA
| | - Min Kim
- Medicine Branch, National Cancer Institute, National Institutes of Health, Bethesda, MD 20892, USA
| | - Aishe Chen
- Molecular Recognition Section, Laboratory of Bioorganic Chemistry, National Institute of Diabetes, Digestive and Kidney Diseases, National Institutes of Health, Building 8A, Room B1A-19, Bethesda, MD 20892, USA
| | - Kenneth A. Jacobson
- Molecular Recognition Section, Laboratory of Bioorganic Chemistry, National Institute of Diabetes, Digestive and Kidney Diseases, National Institutes of Health, Building 8A, Room B1A-19, Bethesda, MD 20892, USA
| |
Collapse
|
36
|
González-Benítez E, Guinzberg R, Díaz-Cruz A, Piña E. Regulation of glycogen metabolism in hepatocytes through adenosine receptors. Role of Ca2+ and cAMP. Eur J Pharmacol 2002; 437:105-11. [PMID: 11890897 DOI: 10.1016/s0014-2999(02)01299-2] [Citation(s) in RCA: 40] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
The objective of this work is to identify the adenosine receptor subtype and the triggered events involved in the regulation of hepatic glycogen metabolism. Glycogenolysis, gluconeogenesis, cAMP, and cytosolic Ca2+ ([Ca2+](cyt)) were measured in isolated hepatocytes challenged with adenosine A1, A2A, and A3 receptor-selective agonists. Stimulation of adenosine receptor subtypes with selective agonists in Ca2+ media produced a dose-dependent increase in [Ca2+]cyt with A1>A2=A3, cAMP with A2A, glycogenolysis with A1>A2A>A3, and gluconeogenesis with A2A>A1>A3, in addition, a decrease in cAMP was observed with A1=A3. Comparatively, in Ca2+-free media or with a cell membrane-permeant Ca2+ chelator, activation of these adenosine receptors with the same selective agonists produced a smaller and transient rise in [Ca2+]cyt with A1=A3>A2, no rise in glycogenolysis and gluconeogenesis with A3>A1, but a full rise with A2A. Thus, in isolated rat hepatocytes activation of the adenosine A1 receptor triggered Ca2+-mediated glycogenolysis, activation of the adenosine A2A receptor stimulated cAMP-mediated gluconeogenesis, and activation of the adenosine A3 receptor increased [Ca2+]cyt and decreased cAMP with minor changes in glycogen metabolism.
Collapse
Affiliation(s)
- Elizabeth González-Benítez
- Departamento de Bioquímica, Facultad de Medicina, Universidad Nacional Autónoma de México, Apdo. Postal 70159, Mexico City, México, D.F., 04510, Mexico
| | | | | | | |
Collapse
|
37
|
Abstract
Nonvisual arrestins (arr) modulate G protein-coupled receptor (GPCR) desensitization and internalization and bind to both clathrin (CL) and AP-2 components of the endocytic coated pit (CP). This raises the possibility that endocytosis of some GPCRs may be a consequence of arr-induced de novo CP formation. To directly test this hypothesis, we examined the behavior of green fluorescent protein (GFP)-arr3 in live cells expressing beta2-adrenergic receptors and fluorescent CL. After agonist stimulation, the diffuse GFP-arr3 signal rapidly became punctate and colocalized virtually completely with preexisting CP spots, demonstrating that activated complexes accumulate in previously formed CPs rather than nucleating new CP formation. After arr3 recruitment, CP appeared larger: electron microscopy analysis revealed an increase in both CP number and in the occurrence of clustered CPs. Mutant arr3 proteins with impaired binding to CL or AP-2 displayed reduced recruitment to CPs, but were still capable of inducing CP clustering. In contrast, though constitutively present in CPs, the COOH-terminal moiety of arr3, which contains CP binding sites but lacks receptor binding, did not induce CP clustering. Together, these results indicate that recruitment of functional arr3-GPCR complexes to CP is necessary to induce clustering. Latrunculin B or 16 degrees C blocked CP rearrangements without affecting arr3 recruitment to CP. These results and earlier studies suggest that discrete CP zones exist on cell surfaces, each capable of supporting adjacent CPs, and that the cortical actin membrane skeleton is intimately involved with both the maintenance of existing CPs and the generation of new structures.
Collapse
MESH Headings
- Adrenergic beta-Agonists/pharmacology
- Animals
- Arrestins/genetics
- Arrestins/metabolism
- Bridged Bicyclo Compounds, Heterocyclic/pharmacology
- COS Cells
- Cell Line
- Chlorocebus aethiops
- Coated Pits, Cell-Membrane/metabolism
- Coated Pits, Cell-Membrane/ultrastructure
- Endocytosis/physiology
- GTP-Binding Proteins/metabolism
- Humans
- Image Processing, Computer-Assisted
- Isoproterenol/pharmacology
- Receptor, Muscarinic M1
- Receptors, Adrenergic, beta-2/genetics
- Receptors, Adrenergic, beta-2/metabolism
- Receptors, Cell Surface/metabolism
- Receptors, Muscarinic/metabolism
- Recombinant Fusion Proteins/genetics
- Recombinant Fusion Proteins/metabolism
- Thiazoles/pharmacology
- Thiazolidines
Collapse
Affiliation(s)
- Francesca Santini
- Kimmel Cancer Institute and the Department of Microbiology and Immunology, Thomas Jefferson University, Philadelphia, PA 19107, USA
| | | | | |
Collapse
|
38
|
van Muijlwijk-Koezen JE, Timmerman H, Ijzerman AP. The adenosine A3 receptor and its ligands. PROGRESS IN MEDICINAL CHEMISTRY 2002; 38:61-113. [PMID: 11774799 DOI: 10.1016/s0079-6468(08)70092-4] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 02/23/2023]
Affiliation(s)
- J E van Muijlwijk-Koezen
- Leiden/Amsterdam Center for Drug Research, Division of Medicinal Chemistry, Department of Pharmacochemistry, Vrije Universiteit, De Boelelaan 1083, 1081 HV Amsterdam, The Netherlands
| | | | | |
Collapse
|
39
|
Hundley TR, Prasad AR, Beaven MA. Elevated levels of cyclooxygenase-2 in antigen-stimulated mast cells is associated with minimal activation of p38 mitogen-activated protein kinase. JOURNAL OF IMMUNOLOGY (BALTIMORE, MD. : 1950) 2001; 167:1629-36. [PMID: 11466386 DOI: 10.4049/jimmunol.167.3.1629] [Citation(s) in RCA: 32] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/19/2022]
Abstract
We have investigated possible factors that underlie changes in the production of eicosanoids after prolonged exposure of mast cells to Ag. Ag stimulation of cultured RBL-2H3 mast cells resulted in increased expression of cyclooxygenase (COX-2) protein and message. Other eicosanoid-related enzymes, namely COX-1, 5-lipoxygenase, and cytosolic phospholipase A(2) were not induced. Activation of extracellular signal-regulated kinase, c-Jun N-terminal kinase, and p38 mitogen-activated protein (MAP) kinase preceded the induction of COX-2, whereas phosphatidylinositol 3' kinase and its substrate, Akt, were constitutively activated in RBL-2H3 cells. Studies with pharmacologic inhibitors indicated that of these kinases, only p38 MAP kinase regulated expression of COX-2. The induction of COX-2 was blocked by the p38 MAP kinase inhibitor SB202190, even when added 12-16 h after stimulation with Ag when p38 MAP kinase activity had returned to near basal, but still minimally elevated, levels. Interestingly, expression of COX-2 as well as cytosolic phospholipase A(2) and 5-lipoxygenase were markedly reduced by SB202190 in unstimulated cells. Collectively, the results imply that p38 MAP kinase regulates expression of eicosanoid-related enzymes, passively or actively, at very low levels of activity in RBL-2H3 cells. Also, comparison with published data suggest that different MAP kinases regulate induction of COX-2 in inflammatory cells of different and even similar phenotype and suggest caution in extrapolating results from one type of cell to another.
Collapse
Affiliation(s)
- T R Hundley
- Laboratory of Molecular Immunology, National Heart, Lung, and Blood Institute, National Institutes of Health, Bethesda, MD 20892, USA
| | | | | |
Collapse
|
40
|
Ramkumar V, Hallam DM, Nie Z. Adenosine, oxidative stress and cytoprotection. JAPANESE JOURNAL OF PHARMACOLOGY 2001; 86:265-74. [PMID: 11488425 DOI: 10.1254/jjp.86.265] [Citation(s) in RCA: 62] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 02/05/2023]
Abstract
Adenosine, a metabolite of ATP, serves a number of important physiological roles in the body. These actions contribute to sedation, bradycardia, vasorelaxation, inhibition of lipolysis and regulation of the immune system and are mediated, in part, through activation of three distinct adenosine receptor (AR) subtypes. To date, four receptor types have been cloned: A1, A2A, A2B and A3. It is becoming increasing clear that adenosine contributes significantly to cytoprotection, a function mediated principally by the A1AR and A3AR. In this review, we survey the literature on the role of adenosine and the mechanisms underlying cytoprotection and ischemic preconditioning, a process characterized by cytoprotection derived from repeated brief ischemic challenges. An important recent observation is that the expression of several AR subtypes could be regulated by oxidative stress to provide a greater cytoprotective role. Thus, like other proteins known to be regulated during ischemia, the A1AR and A3AR can be considered as being inducible receptors.
Collapse
Affiliation(s)
- V Ramkumar
- Southern Illinois University School of Medicine, Department of Pharmacology, Springfield 62794-9620, USA.
| | | | | |
Collapse
|
41
|
Field KA, Apgar JR, Hong-Geller E, Siraganian RP, Baird B, Holowka D. Mutant RBL mast cells defective in Fc epsilon RI signaling and lipid raft biosynthesis are reconstituted by activated Rho-family GTPases. Mol Biol Cell 2000; 11:3661-73. [PMID: 11029062 PMCID: PMC15022 DOI: 10.1091/mbc.11.10.3661] [Citation(s) in RCA: 33] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/24/2023] Open
Abstract
Characterization of defects in a variant subline of RBL mast cells has revealed a biochemical event proximal to IgE receptor (Fc epsilon RI)-stimulated tyrosine phosphorylation that is required for multiple functional responses. This cell line, designated B6A4C1, is deficient in both Fc epsilon RI-mediated degranulation and biosynthesis of several lipid raft components. Agents that bypass receptor-mediated Ca(2+) influx stimulate strong degranulation responses in these variant cells. Cross-linking of IgE-Fc epsilon RI on these cells stimulates robust tyrosine phosphorylation but fails to mobilize a sustained Ca(2+) response. Fc epsilon RI-mediated inositol phosphate production is not detectable in these cells, and failure of adenosine receptors to mobilize Ca(2+) suggests a general deficiency in stimulated phospholipase C activity. Antigen stimulation of phospholipases A(2) and D is also defective. Infection of B6A4C1 cells with vaccinia virus constructs expressing constitutively active Rho family members Cdc42 and Rac restores antigen-stimulated degranulation, and active Cdc42 (but not active Rac) restores ganglioside and GPI expression. The results support the hypothesis that activation of Cdc42 and/or Rac is critical for Fc epsilon RI-mediated signaling that leads to Ca(2+) mobilization and degranulation. Furthermore, they suggest that Cdc42 plays an important role in the biosynthesis and expression of certain components of lipid rafts.
Collapse
Affiliation(s)
- K A Field
- Department of Chemistry and Chemical Biology, Cornell University, Ithaca, New York, USA
| | | | | | | | | | | |
Collapse
|
42
|
Trincavelli ML, Tuscano D, Cecchetti P, Falleni A, Benzi L, Klotz KN, Gremigni V, Cattabeni F, Lucacchini A, Martini C. Agonist-induced internalization and recycling of the human A(3) adenosine receptors: role in receptor desensitization and resensitization. J Neurochem 2000; 75:1493-501. [PMID: 10987829 DOI: 10.1046/j.1471-4159.2000.0751493.x] [Citation(s) in RCA: 47] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
Abstract
A(3) adenosine receptors have been proposed to play an important role in the pathophysiology of cerebral ischemia with a regimen-dependent nature of the therapeutic effects probably related to receptor desensitization and down-regulation. Here we studied the agonist-induced internalization of human A(3) adenosine receptors in transfected Chinese hamster ovary cells, and then we evaluated the relationship between internalization and signal desensitization and resensitization. Binding of N(6)-(4-amino-3-[(125)I]iodobenzyl)adenosine-5'-N-methyluronamide to membranes from Chinese hamster ovary cells stably transfected with the human A(3) adenosine receptor showed a profile typical of these receptors in other cell lines (K:(D) = 1.3+/-0.08 nM; B(max) = 400+/-28 fmol/mg of proteins). The iodinated agonist, bound at 4 degrees C to whole transfected cells, was internalized by increasing the temperature to 37 degrees C with a rate constant of 0.04+/-0.034 min(-1). Agonist-induced internalization of A(3) adenosine receptors was directly demonstrated by immunogold electron microscopy, which revealed the localization of these receptors in plasma membranes and intracellular vesicles. Moreover, short-term exposure of these cells to the agonist caused rapid desensitization as tested in adenylyl cyclase assays. Subsequent removal of the agonist led to restoration of the receptor function and recycling of the receptors to the cell surface. The rate constant of receptor recycling was 0.02+/-0.0017 min(-1). Blockade of internalization and recycling demonstrated that internalization did not affect signal desensitization, whereas recycling of internalized receptors was implicated in the signal resensitization.
Collapse
Affiliation(s)
- M L Trincavelli
- Dipartimento di Psichiatria, Neurobiologia, Farmacologia e Biotecnologie, Università di Pisa, Pisa, Italia
| | | | | | | | | | | | | | | | | | | |
Collapse
|
43
|
Santini F, Penn RB, Gagnon AW, Benovic JL, Keen JH. Selective recruitment of arrestin-3 to clathrin coated pits upon stimulation of G protein-coupled receptors. J Cell Sci 2000; 113 ( Pt 13):2463-70. [PMID: 10852825 DOI: 10.1242/jcs.113.13.2463] [Citation(s) in RCA: 41] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/25/2023] Open
Abstract
Non-visual arrestins (arrestin-2 and arrestin-3) play critical roles in the desensitization and internalization of many G protein-coupled receptors. In vitro experiments have shown that both non-visual arrestins bind with high and approximately comparable affinities to activated, phosphorylated forms of receptors. They also exhibit high affinity binding, again of comparable magnitude, to clathrin. Further, agonist-promoted internalization of many receptors has been found to be stimulated by exogenous over-expression of either arrestin2 or arrestin3. The existence of multiple arrestins raises the question whether stimulated receptors are selective for a specific endogenous arrestin under more physiological conditions. Here we address this question in RBL-2H3 cells, a cell line that expresses comparable levels of endogenous arrestin-2 and arrestin-3. When (beta)(2)-adrenergic receptors are stably expressed in these cells the receptors internalize efficiently following agonist stimulation. However, by immunofluorescence microscopy we determine that only arrestin-3, but not arrestin-2, is rapidly recruited to clathrin coated pits upon receptor stimulation. Similarly, in RBL-2H3 cells that stably express physiological levels of m1AChR, the addition of carbachol selectively induces the localization of arrestin-3, but not arrestin-2, to coated pits. Thus, this work demonstrates coupling of G protein-coupled receptors to a specific non-visual arrestin in an in vivo setting.
Collapse
MESH Headings
- Arrestins/metabolism
- Clathrin/metabolism
- Coated Pits, Cell-Membrane/metabolism
- GTP-Binding Proteins/metabolism
- Phosphoproteins/metabolism
- Receptor, Adenosine A3
- Receptor, Muscarinic M1
- Receptors, Adrenergic, beta-2/metabolism
- Receptors, Cell Surface/drug effects
- Receptors, Cell Surface/metabolism
- Receptors, Muscarinic/drug effects
- Receptors, Muscarinic/metabolism
- Receptors, Purinergic P1/drug effects
- Receptors, Purinergic P1/metabolism
- Signal Transduction/physiology
- Tumor Cells, Cultured
Collapse
Affiliation(s)
- F Santini
- Department of Microbiology and Immunology and the Kimmel Cancer Institute, Thomas Jefferson University, Philadelphia, PA 19107, USA.
| | | | | | | | | |
Collapse
|
44
|
Shin Y, Daly JW, Choi OH. Diverse effects of sphingosine on calcium mobilization and influx in differentiated HL-60 cells. Cell Calcium 2000; 27:269-80. [PMID: 10859593 DOI: 10.1054/ceca.2000.0118] [Citation(s) in RCA: 13] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022]
Abstract
Sphingosine induces a biphasic increase in cytosolic-free Ca(2+)([Ca(2+)](i)) with an initial peak followed by a sustained increase in HL-60 cells differentiated into neutrophil-like cells. The initial peak is not affected by the presence of ethylene glycol bis (beta-aminoethyl ether) N, N, N', N-tetraacetic acid (EGTA) in the buffer and appears to be dependent on conversion of sphingosine to sphingosine -1-phosphate (S1P) by sphingosine kinase, since it is blocked by the presence of N, N-dimethylsphingosine (DMS), which, like sphingosine, causes a sustained increase itself. The sustained increase that is elicited by sphingosine or DMS is abolished by the presence of EGTA in the buffer. The sustained sphingosine-induced Ca(2+)influx does not appear due to Ca(2+)influx through store-operated Ca(2+)(SOC) channels, since the influx is not inhibited by SKF 96365, nor is it augmented by loperamide. In addition, sphingosine and DMS attenuate the Ca(2+)influx through SOC channels that occurs after depletion of intracellular stores by ATP or thapsigargin. Both the initial peak and the sustained increase in [Ca(2+)](i)elicited by sphingosine can be blocked by phorbol 12-myristate 13-acetate (PMA)-elicited activation of protein kinase C. Thus, in HL-60 cells sphingosine causes a mobilization of Ca(2+)from intracellular Ca(2+)stores, which requires conversion to S1P, while both sphingosine and DMS elicit a Ca(2+)influx through an undefined Ca(2+)channel and cause a blockade of SOC channels.
Collapse
Affiliation(s)
- Y Shin
- Laboratory of Bioorganic Chemistry, National Institute of Diabetes and Digestive Disorder of Kidney, National Institutes of Health, Bethesda, Maryland, USA
| | | | | |
Collapse
|
45
|
Baraldi PG, Cacciari B, Romagnoli R, Merighi S, Varani K, Borea PA, Spalluto G. A(3) adenosine receptor ligands: history and perspectives. Med Res Rev 2000; 20:103-28. [PMID: 10723024 DOI: 10.1002/(sici)1098-1128(200003)20:2<103::aid-med1>3.0.co;2-x] [Citation(s) in RCA: 118] [Impact Index Per Article: 4.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
Abstract
Adenosine regulates many physiological functions through specific cell membrane receptors. On the basis of pharmacological studies and molecular cloning, four different adenosine receptors have been identified and classified as A(1), A(2A), A(2B), and A(3). These adenosine receptors are members of the G-protein-coupled receptor family. While adenosine A(1) and A(2A) receptor subtypes have been pharmacologically characterized through the use of selective ligands, the A(3) adenosine receptor subtype is presently under study in order to better understand its physio-pathological functions. Activation of adenosine A(3) receptors has been shown to stimulate phospholipase C and D and to inhibit adenylate cyclase. Activation of A(3) adenosine receptors also causes the release of inflammatory mediators such as histamine from mast cells. These mediators are responsible for processes such as inflammation and hypotension. It has also been suggested that the A(3) receptor plays an important role in brain ischemia, immunosuppression, and bronchospasm in several animal models. Based on these results, highly selective A(3) adenosine receptor agonists and/or antagonists have been indicated as potential drugs for the treatment of asthma and inflammation, while highly selective agonists have been shown to possess cardioprotective effects. The updated material related to this field of research has been rationalized and arranged in order to offer an overview of the topic.
Collapse
Affiliation(s)
- P G Baraldi
- Dipartimento di Scienze Farmaceutiche, Universitá di Ferrara, Via Fossato di Mortara 17-19, I-44100 Ferrara, Italy.
| | | | | | | | | | | | | |
Collapse
|
46
|
Palmer TM, Stiles GL. Identification of Threonine Residues Controlling the Agonist-Dependent Phosphorylation and Desensitization of the Rat A3Adenosine Receptor. Mol Pharmacol 2000. [DOI: 10.1124/mol.57.3.539] [Citation(s) in RCA: 77] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022] Open
|
47
|
Abstract
Adenosine produces a wide variety of physiological effects through the activation of cell surface adenosine receptors (ARs). ARs are members of the G-protein-coupled receptor family, and currently, four subtypes, the A1AR, A2AAR, A2BAR, and A3AR, are recognized. This review focuses on the role of receptor structure in governing various facets of AR activity. Ligand-binding properties of ARs are primarily dictated by amino acids in the transmembrane domains of the receptors, although a role for extracellular domains of certain ARs has been suggested. Studies have identified certain amino acids conserved amongst AR subtypes that are critical for ligand recognition, as well as additional residues that may differentiate between agonist and antagonist ligands. Receptor regions responsible for activation of Gs have been identified for the A2AAR. The location of these intracellular sites is consistent with findings described for other G-protein-coupled receptors. Site-directed mutagenesis has been employed to analyze the structural basis for the differences in the kinetics of the desensitization response displayed by various AR subtypes. For the A2AAR and A3AR, agonist-stimulated phosphorylation of the AR, presumably via a G-protein receptor kinase, has been shown to occur. For these AR subtypes, intracellular regions or individual amino acids that may be targets for this phosphorylation have been identified. Finally, the role of A1AR gene structure in regulating the expression of this AR subtype is reviewed.
Collapse
Affiliation(s)
- M E Olah
- Department of Medicine, Duke University Medical Center, Durham, NC 27710, USA
| | | |
Collapse
|
48
|
Tilley SL, Wagoner VA, Salvatore CA, Jacobson MA, Koller BH. Adenosine and inosine increase cutaneous vasopermeability by activating A(3) receptors on mast cells. J Clin Invest 2000; 105:361-7. [PMID: 10675362 PMCID: PMC377446 DOI: 10.1172/jci8253] [Citation(s) in RCA: 157] [Impact Index Per Article: 6.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/17/2022] Open
Abstract
Adenosine has potent effects on both the cardiovascular and immune systems. Exposure of tissues to adenosine results in increased vascular permeability and extravasation of serum proteins. The mechanism by which adenosine brings about these physiological changes is poorly defined. Using mice deficient in the A(3) adenosine receptor (A(3)AR), we show that increases in cutaneous vascular permeability observed after treatment with adenosine or its principal metabolite inosine are mediated through the A(3)AR. Adenosine fails to increase vascular permeability in mast cell-deficient mice, suggesting that this tissue response to adenosine is mast cell-dependent. Furthermore, this response is independent of activation of the high-affinity IgE receptor (FcepsilonR1) by antigen, as adenosine is equally effective in mediating these changes in FcepsilonR1 beta-chain-deficient mice. Together these results support a model in which adenosine and inosine induce changes in vascular permeability indirectly by activating mast cells, which in turn release vasoactive substances. The demonstration in vivo that adenosine, acting through a specific receptor, can provoke degranulation of this important tissue-based effector cell, independent of antigen activation of the high-affinity IgE receptor, supports an important role for this nucleoside in modifying the inflammatory response.
Collapse
Affiliation(s)
- S L Tilley
- Department of Medicine, Division of Pulmonary and Critical Care Medicine, University of North Carolina-Chapel Hill, Chapel Hill, North Carolina 27599, USA
| | | | | | | | | |
Collapse
|
49
|
Fierro L, Parekh AB. Substantial depletion of the intracellular Ca2+ stores is required for macroscopic activation of the Ca2+ release-activated Ca2+ current in rat basophilic leukaemia cells. J Physiol 2000; 522 Pt 2:247-57. [PMID: 10639101 PMCID: PMC2269755 DOI: 10.1111/j.1469-7793.2000.t01-1-00247.x] [Citation(s) in RCA: 60] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022] Open
Abstract
1. Tight-seal whole-cell patch clamp experiments were performed to examine the ability of different intracellular Ca2+ mobilising agents to activate the Ca2+ release-activated Ca2+ current (ICRAC) in rat basophilic leukaemia (RBL-1) cells under conditions of weak cytoplasmic Ca2+ buffering. 2. Dialysis with a maximal concentration of inositol 1,4,5-trisphosphate (IP3) routinely failed to activate macroscopic ICRAC in low buffer (0.mM EGTA, BAPTA or dimethyl BAPTA), whereas it activated the current to its maximal extent in high buffer (10 mM EGTA). Dialysis with a poorly metabolisable analogue of IP3, with ionomycin, or with IP3 and ionomycin all failed to generate macroscopic ICRAC in low Ca2+ buffering conditions. 3. Dialysis with the sarco/endoplasmic reticulum Ca2+-ATPase (SERCA) pump blocker thapsigargin was able to activate ICRAC even in the presence of low cytoplasmic Ca2+ buffering, albeit at a slow rate. Exposure to IP3 together with the SERCA blockers thapsigargin, thapsigargicin or cyclopiazonic acid rapidly activated ICRAC in low buffer. 4. Following activation of ICRAC by intracellular dialysis with IP3 and thapsigargin in low buffer, the current was very selective for Ca2+ (apparent KD of 1 mM) Sr2+ and Ba2+ were less effective charge carriers and Na+ was not conducted to any appreciable extent. The ionic selectivity of ICRAC was very similar in low or high intracellular Ca2+ buffer. 5. Fast Ca2+-dependent inactivation of ICRAC occurred at a similar rate and to a similar extent in low or high Ca2+ buffer. Ca2+-dependent inactivation is not the reason why macroscopic ICRAC cannot be seen under conditions of low cytoplasmic Ca2+ buffering. 6. ICRAC could be activated by combining IP3 with thapsigargin, even in the presence of 100 microM Ca2+ and the absence of any exogenous Ca2+ chelator, where ATP and glutamate represented the only Ca2+ buffers in the pipette solution. 7. Our results suggest that a threshold exists within the IP3-sensitive Ca2+ store, below which intraluminal Ca2+ needs to fall before ICRAC activates. Possible models to explain the results are discussed.
Collapse
Affiliation(s)
- L Fierro
- Laboratory of Molecular and Cellular Signalling, Department of Physiology, University of Oxford, Parks Road, Oxford OX1 3PT, UK
| | | |
Collapse
|
50
|
Narenjkar J, Marsh SJ, Assem ES. The characterization and quantification of antigen-induced Ca2+ oscillations in a rat basophilic leukaemia cell line (RBL-2H3). Cell Calcium 1999; 26:261-9. [PMID: 10668564 DOI: 10.1054/ceca.1999.0065] [Citation(s) in RCA: 20] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022]
Abstract
Using the ratiometric Ca2+ indicator, indo-1, the antigen-induced increase in intracellular Ca2+ concentration ([Ca2+]i) was measured in individual RBL-2H3 cells which had been passively sensitized with monoclonal antibody to the dintrophenyl (DNP) haptenic group. Antigenic stimulation using DNP-human serum albumin conjugate (DNP-HSA) induced concentration-dependent asynchronous Ca2+ oscillations, or irregular spikes. To achieve a quantitative comparison of the effects of different concentrations of antigen on changes in Ca2+[i, the area under the curve (AUC) of Ca2+ oscillations in each cell was calculated. The dose-response curve of the calculated AUC is consistent with the bell-shaped dose-response curve for antigen-induced mediator release, depolarization and 86Rb(+)-efflux. Ca2+ oscillations induced by antigenic stimulation were abolished by removal of external Ca2+ and the subsequent reintroduction of external Ca2+ caused their resumption. To investigate the role of Ca2+ oscillations in the secretory response, changes in [Ca2+]i induced by concanavalin A (Con-A), A23187, thapsigargin and NECA were also monitored. Con-A mimicked the response induced by antigen, whilst A23187 and thapsigargin induced a large transient non-oscillatory response. NECA, an adenosine receptor agonist, induced only a small transient rise in Ca2+[i without oscillatory behaviour. Since all these stimuli accept NECA-induced degranulation in these cells, it is suggested that, although Ca2+ oscillations are not essential for the initiation of secretion, they probably underlie the in-vivo physiological response of mast cells and basophils to an antigenic challenge. They also seem to enhance the efficacy of the Ca2+ signal.
Collapse
Affiliation(s)
- J Narenjkar
- Department of Pharmacology, University College London, UK
| | | | | |
Collapse
|