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Pacini ESA, Satori NA, Jackson EK, Godinho RO. Extracellular cAMP-Adenosine Pathway Signaling: A Potential Therapeutic Target in Chronic Inflammatory Airway Diseases. Front Immunol 2022; 13:866097. [PMID: 35479074 PMCID: PMC9038211 DOI: 10.3389/fimmu.2022.866097] [Citation(s) in RCA: 4] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/30/2022] [Accepted: 03/21/2022] [Indexed: 12/25/2022] Open
Abstract
Adenosine is a purine nucleoside that, via activation of distinct G protein-coupled receptors, modulates inflammation and immune responses. Under pathological conditions and in response to inflammatory stimuli, extracellular ATP is released from damaged cells and is metabolized to extracellular adenosine. However, studies over the past 30 years provide strong evidence for another source of extracellular adenosine, namely the “cAMP-adenosine pathway.” The cAMP-adenosine pathway is a biochemical mechanism mediated by ATP-binding cassette transporters that facilitate cAMP efflux and by specific ectoenzymes that convert cAMP to AMP (ecto-PDEs) and AMP to adenosine (ecto-nucleotidases such as CD73). Importantly, the cAMP-adenosine pathway is operative in many cell types, including those of the airways. In airways, β2-adrenoceptor agonists, which are used as bronchodilators for treatment of asthma and chronic respiratory diseases, stimulate cAMP efflux and thus trigger the extracellular cAMP-adenosine pathway leading to increased concentrations of extracellular adenosine in airways. In the airways, extracellular adenosine exerts pro-inflammatory effects and induces bronchoconstriction in patients with asthma and chronic obstructive pulmonary diseases. These considerations lead to the hypothesis that the cAMP-adenosine pathway attenuates the efficacy of β2-adrenoceptor agonists. Indeed, our recent findings support this view. In this mini-review, we will highlight the potential role of the extracellular cAMP-adenosine pathway in chronic respiratory inflammatory disorders, and we will explore how extracellular cAMP could interfere with the regulatory effects of intracellular cAMP on airway smooth muscle and innate immune cell function. Finally, we will discuss therapeutic possibilities targeting the extracellular cAMP-adenosine pathway for treatment of these respiratory diseases.
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Affiliation(s)
- Enio Setsuo Arakaki Pacini
- Division of Cellular Pharmacology, Department of Pharmacology, Universidade Federal de São Paulo, São Paulo, Brazil
| | - Naiara Ayako Satori
- Division of Cellular Pharmacology, Department of Pharmacology, Universidade Federal de São Paulo, São Paulo, Brazil
| | - Edwin Kerry Jackson
- Department of Pharmacology and Chemical Biology, University of Pittsburgh School of Medicine, Pittsburgh, PA, United States
| | - Rosely Oliveira Godinho
- Division of Cellular Pharmacology, Department of Pharmacology, Universidade Federal de São Paulo, São Paulo, Brazil
- *Correspondence: Rosely Oliveira Godinho,
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2
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Jones C, Bisserier M, Bueno-Beti C, Bonnet G, Neves-Zaph S, Lee SY, Milara J, Dorfmüller P, Humbert M, Leopold JA, Hadri L, Hajjar RJ, Sassi Y. A novel secreted-cAMP pathway inhibits pulmonary hypertension via a feed-forward mechanism. Cardiovasc Res 2021; 116:1500-1513. [PMID: 31529026 DOI: 10.1093/cvr/cvz244] [Citation(s) in RCA: 10] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 06/20/2019] [Revised: 07/31/2019] [Accepted: 09/10/2019] [Indexed: 11/14/2022] Open
Abstract
AIMS Cyclic adenosine monophosphate (cAMP) is the predominant intracellular second messenger that transduces signals from Gs-coupled receptors. Intriguingly, there is evidence from various cell types that an extracellular cAMP pathway is active in the extracellular space. Herein, we investigated the role of extracellular cAMP in the lung and examined whether it may act on pulmonary vascular cell proliferation and pulmonary vasculature remodelling in the pathogenesis of pulmonary hypertension (PH). METHODS AND RESULTS The expression of cyclic AMP-metabolizing enzymes was increased in lungs from patients with PH as well as in rats treated with monocrotaline and mice exposed to Sugen/hypoxia. We report that inhibition of the endogenous extracellular cAMP pathway exacerbated Sugen/hypoxia-induced lung remodelling. We found that application of extracellular cAMP induced an increase in intracellular cAMP levels and inhibited proliferation and migration of pulmonary vascular cells in vitro. Extracellular cAMP infusion in two in vivo PH models prevented and reversed pulmonary and cardiac remodelling associated with PH. Using protein expression analysis along with luciferase assays, we found that extracellular cAMP acts via the A2R/PKA/CREB/p53/Cyclin D1 pathway. CONCLUSIONS Taken together, our data reveal the presence of an extracellular cAMP pathway in pulmonary arteries that attempts to protect the lung during PH, and suggest targeting of the extracellular cAMP signalling pathway to limit pulmonary vascular remodelling and PH.
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Affiliation(s)
- Carly Jones
- Cardiovascular Research Center, Icahn School of Medicine at Mount Sinai, One Gustave L. Levy Place, Box 1030, New York, NY 10029, USA
| | - Malik Bisserier
- Cardiovascular Research Center, Icahn School of Medicine at Mount Sinai, One Gustave L. Levy Place, Box 1030, New York, NY 10029, USA
| | - Carlos Bueno-Beti
- Cardiovascular Research Center, Icahn School of Medicine at Mount Sinai, One Gustave L. Levy Place, Box 1030, New York, NY 10029, USA
| | - Guillaume Bonnet
- Cardiovascular Research Center, Icahn School of Medicine at Mount Sinai, One Gustave L. Levy Place, Box 1030, New York, NY 10029, USA
| | - Susana Neves-Zaph
- Department of Pharmacological Sciences, Icahn School of Medicine at Mount Sinai, One Gustave Levy Place, New York, 10029 NY; USA.,Systems Biology Center, Icahn School of Medicine at Mount Sinai, One Gustave Levy Place, New York, 10029 NY; USA
| | - Sang-Yong Lee
- Pharma-Zentrum Bonn, Pharmazeutisches Institut, Pharmazeutische Chemie I, Universität Bonn, Bonn, Germany
| | - Javier Milara
- Health Research Institute INCLIVA, Valencia, Spain.,Pharmacy Unit, University Clinic Hospital, Valencia, Spain.,CIBERES, Health Institute Carlos III, Valencia, Spain
| | - Peter Dorfmüller
- Université Paris-Sud, Faculté de Médecine, Université Paris-Saclay, Le Kremlin-Bicêtre, France.,Service de Pneumologie, Hôpital Bicêtre, AP-HP, Le Kremlin-Bicêtre, France.,INSERM UMR_S 999, Hôpital Marie Lannelongue, Le Plessis Robinson, France
| | - Marc Humbert
- Université Paris-Sud, Faculté de Médecine, Université Paris-Saclay, Le Kremlin-Bicêtre, France.,Service de Pneumologie, Hôpital Bicêtre, AP-HP, Le Kremlin-Bicêtre, France.,INSERM UMR_S 999, Hôpital Marie Lannelongue, Le Plessis Robinson, France
| | - Jane A Leopold
- Brigham and Women's Hospital, Harvard Medical School, Boston, MA, USA
| | - Lahouaria Hadri
- Cardiovascular Research Center, Icahn School of Medicine at Mount Sinai, One Gustave L. Levy Place, Box 1030, New York, NY 10029, USA
| | | | - Yassine Sassi
- Cardiovascular Research Center, Icahn School of Medicine at Mount Sinai, One Gustave L. Levy Place, Box 1030, New York, NY 10029, USA
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3
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Xin M, Feng J, Hao Y, You J, Wang X, Yin X, Shang P, Ma D. Cyclic adenosine monophosphate in acute ischemic stroke: some to update, more to explore. J Neurol Sci 2020; 413:116775. [PMID: 32197118 DOI: 10.1016/j.jns.2020.116775] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/26/2019] [Revised: 03/10/2020] [Accepted: 03/11/2020] [Indexed: 12/14/2022]
Abstract
The development of effective treatment for ischemic stroke, which is a common cause of morbidity and mortality worldwide, remains an unmet goal because the current first-line treatment management interventional therapy has a strict time window and serious complications. In recent years, a growing body of evidence has shown that the elevation of intracellular and extracellular cyclic adenosine monophosphate (cAMP) alleviates brain damage after ischemic stroke by attenuating neuroinflammation in the central nervous system and peripheral immune system. In the central nervous system, upregulated intracellular cAMP signaling can alleviate immune-mediated damage by restoring neuronal morphology and function, inhibiting microglia migration and activation, stabilizing the membrane potential of astrocytes and improving the cellular functions of endothelial cells and oligodendrocytes. Enhancement of the extracellular cAMP signaling pathway can improve neurological function by activating the cAMP-adenosine pathway to reduce immune-mediated damage. In the peripheral immune system, cAMP can act on various immune cells to suppress peripheral immune function, which can alleviate the inflammatory response in the central nervous system and improve the prognosis of acute cerebral ischemic injury. Therefore, cAMP may play key roles in reducing post-stroke neuroinflammatory damage. The protective roles of the cAMP indicate that the cAMP enhancing drugs such as cAMP supplements, phosphodiesterase inhibitors, adenylate cyclase agonists, which are currently used in the treatment of heart and lung diseases. They are potentially able to be applied as a new therapeutic strategy in ischemic stroke. This review focuses on the immune-regulating roles and the clinical implication of cAMP in acute ischemic stroke.
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Affiliation(s)
- Meiying Xin
- Department of Neurology, Jilin University First Hospital, Changchun, Jilin, China
| | - Jiachun Feng
- Department of Neurology, Jilin University First Hospital, Changchun, Jilin, China.
| | - Yulei Hao
- Department of Neurology, Jilin University First Hospital, Changchun, Jilin, China
| | - Jiulin You
- Department of Neurology, Jilin University First Hospital, Changchun, Jilin, China
| | - Xinyu Wang
- Department of Neurology, Jilin University First Hospital, Changchun, Jilin, China
| | - Xiang Yin
- Department of Neurology, Jilin University First Hospital, Changchun, Jilin, China
| | - Pei Shang
- Department of Neurology, Jilin University First Hospital, Changchun, Jilin, China
| | - Di Ma
- Department of Neurology, Jilin University First Hospital, Changchun, Jilin, China.
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Sayner SL, Choi CS, Maulucci ME, Ramila KC, Zhou C, Scruggs AK, Yarbrough T, Blair LA, King JA, Seifert R, Kaever V, Bauer NN. Extracellular vesicles: another compartment for the second messenger, cyclic adenosine monophosphate. Am J Physiol Lung Cell Mol Physiol 2019; 316:L691-L700. [PMID: 30758991 PMCID: PMC6483015 DOI: 10.1152/ajplung.00282.2018] [Citation(s) in RCA: 20] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/15/2018] [Revised: 01/16/2019] [Accepted: 02/01/2019] [Indexed: 12/17/2022] Open
Abstract
The second messenger, cAMP, is highly compartmentalized to facilitate signaling specificity. Extracellular vesicles (EVs) are submicron, intact vesicles released from many cell types that can act as biomarkers or be involved in cell-to-cell communication. Although it is well recognized that EVs encapsulate functional proteins and RNAs/miRNAs, currently it is unclear whether cyclic nucleotides are encapsulated within EVs to provide an additional second messenger compartment. Using ultracentrifugation, EVs were isolated from the culture medium of unstimulated systemic and pulmonary endothelial cells. EVs were also isolated from pulmonary microvascular endothelial cells (PMVECs) following stimulation of transmembrane adenylyl cyclase (AC) in the presence or absence of the phosphodiesterase 4 inhibitor rolipram over time. Whereas cAMP was detected in EVs isolated from endothelial cells derived from different vascular beds, it was highest in EVs isolated from PMVECs. Treatment of PMVECs with agents that increase near-membrane cAMP led to an increase in cAMP within corresponding EVs, yet there was no increase in EV number. Elevated cell cAMP, measured by whole cell measurements, peaked 15 min after treatment, yet in EVs the peak increase in cAMP was delayed until 60 min after cell stimulation. Cyclic AMP was also increased in EVs collected from the perfusate of isolated rat lungs stimulated with isoproterenol and rolipram, thus corroborating cell culture findings. When added to unperturbed confluent PMVECs, EVs containing elevated cAMP were not barrier disruptive like cytosolic cAMP but maintained monolayer resistance. In conclusion, PMVECs release EVs containing cAMP, providing an additional compartment to cAMP signaling.
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Affiliation(s)
- Sarah L Sayner
- Department of Physiology Cell Biology, University of South Alabama , Mobile, Alabama
- Center for Lung Biology, University of South Alabama , Mobile, Alabama
| | - Chung-Sik Choi
- Department of Physiology Cell Biology, University of South Alabama , Mobile, Alabama
| | - Marcy E Maulucci
- Department of Physiology Cell Biology, University of South Alabama , Mobile, Alabama
| | - K C Ramila
- Department of Physiology Cell Biology, University of South Alabama , Mobile, Alabama
| | - Chun Zhou
- Department of Physiology Cell Biology, University of South Alabama , Mobile, Alabama
| | - April K Scruggs
- Department of Physiology Pharmacology, University of South Alabama , Mobile, Alabama
- Center for Lung Biology, University of South Alabama , Mobile, Alabama
| | - Thomas Yarbrough
- Department of Physiology Biochemistry, University of South Alabama , Mobile, Alabama
- Center for Lung Biology, University of South Alabama , Mobile, Alabama
| | - Leslie A Blair
- Department of Physiology Pharmacology, University of South Alabama , Mobile, Alabama
- Center for Lung Biology, University of South Alabama , Mobile, Alabama
| | - Judy A King
- Department of Pathology and Translational Pathobiology, Louisiana State University Health , Shreveport, Louisiana
| | - Roland Seifert
- Institute of Pharmacology, Hanover Medical School , Hanover , Germany
| | - Volkhard Kaever
- Research Core Unit, Metabolomics, Hanover Medical School , Hanover , Germany
| | - Natalie N Bauer
- Department of Physiology Pharmacology, University of South Alabama , Mobile, Alabama
- Center for Lung Biology, University of South Alabama , Mobile, Alabama
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Riccomi A, Gesa V, Sacchi A, De Magistris MT, Vendetti S. Modulation of Phenotype and Function of Human CD4 +CD25 + T Regulatory Lymphocytes Mediated by cAMP-Elevating Agents. Front Immunol 2016; 7:358. [PMID: 27703455 PMCID: PMC5028705 DOI: 10.3389/fimmu.2016.00358] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/14/2016] [Accepted: 09/01/2016] [Indexed: 01/21/2023] Open
Abstract
We have shown that cholera toxin (CT) and other cyclic AMP (cAMP)-elevating agents induce upregulation of the inhibitory molecule CTLA-4 in human resting CD4+ T lymphocytes, which following the treatment acquired suppressive functions. In this study, we evaluated the effect of cAMP-elevating agents on human CD4+CD25+ T cells, which include the T regulatory cells (Tregs) that play a pivotal role in the maintenance of immunological tolerance. We found that cAMP-elevating agents induce upregulation of CTLA-4 in CD4+CD25− and further enhance its expression in CD4+CD25+ T cells. We observed an increase of two isoforms of mRNA coding for the membrane and the soluble CTLA-4 molecules, suggesting that the regulation of CTLA-4 expression by cAMP is at the transcriptional level. In addition, we found that the increase of cAMP in CD4+CD25+ T cells converts the CD4+CD25+Foxp3− T cells in CD4+CD25+Foxp3+ T cells, whereas the increase of cAMP in CD4+CD25− T cells did not upregulate Foxp3 in the absence of activation stimuli. To investigate the function of these cells, we performed an in vitro suppression assay by culturing CD4+CD25+ T cells untreated or pre-treated with CT with anti-CD3 mAbs-stimulated autologous peripheral blood mononuclear cell. We found that CT enhances the inhibitory function of CD4+CD25+ T cells, CD4+, and CD8+ T cell proliferation and IFNγ production are strongly inhibited by CD4+CD25+ T cells pre-treated with cAMP-elevating agents. Furthermore, we found that CD4+CD25+ T lymphocytes pre-treated with cAMP-elevating agents induce the upregulation of CD80 and CD86 co-stimulatory molecules on immature dendritic cells (DCs) in the absence of antigenic stimulation, however without leading to full DC maturation. These data show that the increase of intracellular cAMP modulates the phenotype and function of human CD4+CD25+ T cells.
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Affiliation(s)
- Antonella Riccomi
- Department of Infectious, Parasitic and Immune-Mediated Diseases, Istituto Superiore di Sanità , Rome , Italy
| | - Valentina Gesa
- Department of Infectious, Parasitic and Immune-Mediated Diseases, Istituto Superiore di Sanità , Rome , Italy
| | - Alessandra Sacchi
- Department of Epidemiology, Preclinical Research, and Advanced Diagnostics, National Institute for Infectious Diseases IRCCS "Lazzaro Spallanzani" , Rome , Italy
| | - Maria Teresa De Magistris
- Department of Infectious, Parasitic and Immune-Mediated Diseases, Istituto Superiore di Sanità , Rome , Italy
| | - Silvia Vendetti
- Department of Infectious, Parasitic and Immune-Mediated Diseases, Istituto Superiore di Sanità , Rome , Italy
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6
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Tsai HC, Wu R. Mechanisms of Cholera Toxin in the Modulation of TH17 Responses. Crit Rev Immunol 2016; 35:135-52. [PMID: 26351147 DOI: 10.1615/critrevimmunol.2015012295] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/05/2023]
Abstract
Numerous studies have shown that TH17 cells and their signature cytokine IL-17A are critical to host defense against various bacterial and fungal infections. The protective responses mediated by TH17 cells and IL-17A include the recruitment of neutrophils, release of antimicrobial peptides and chemokines, and enhanced tight junction of epithelial cells. Due to the importance of TH17 cells in infections, efforts have been made to develop TH17-based vaccines. The goal of vaccination is to establish a protective immunological memory. Most currently approved vaccines are antibody-based and have limited protection against stereotypically different strains. Studies show that T-cell-based vaccines may overcome this limitation and protect hosts against infection of different strains. Two main strategies are used to develop TH17 vaccines: identification of TH17-specific antigens and TH17-skewing adjuvants. Studies have revealed that cholera toxin (CT) induces a potent Th17 response following vaccination. Antigen vaccination along with CT induces a robust TH17 response, which is sometimes accompanied by TH1 responses. Due to the toxicity of CT, it is hard to apply CT in a clinical setting. Thus, understanding how CT modulates TH17 responses may lead to the development of successful TH17-based vaccines.
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Affiliation(s)
- Hsing-Chuan Tsai
- Department of Neurology and Neurological Sciences, Stanford University School of Medicine, Stanford, California, USA
| | - Reen Wu
- Center for Comparative Respiratory Biology and Medicine, University of California, USA
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7
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Wang SM, Chen IC, Liao YT, Liu CC. The clinical correlation of regulatory T cells and cyclic adenosine monophosphate in enterovirus 71 infection. PLoS One 2014; 9:e102025. [PMID: 25010330 PMCID: PMC4092122 DOI: 10.1371/journal.pone.0102025] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/04/2014] [Accepted: 06/13/2014] [Indexed: 11/23/2022] Open
Abstract
Background Brainstem encephalitis (BE) and pulmonary edema (PE) are notable complications of enterovirus 71 (EV71) infection. Objective This study investigated the immunoregulatory characterizations of EV71 neurological complications by disease severity and milrinone treatment. Study Design Patients <18 years with virologically confirmed EV71 infections were enrolled and divided into 2 groups: the hand, foot, and mouth disease (HFMD) or BE group, and the autonomic nervous system (ANS) dysregulation or PE group. Cytokine and cyclic adenosine monophosphate (cAMP) levels, and the regulatory T cell (Tregs) profiles of the patients were determined. Results Patients with ANS dysregulation or PE exhibited significantly low frequency of CD4+CD25+Foxp3+ and CD4+Foxp3+ T cells compared with patients with HFMD or BE. The expression frequency of CD4−CD8− was also significantly decreased in patients with ANS dysregulation or PE. Among patients with ANS dysregulation or PE, the expression frequency of CD4+Foxp3+ increased markedly after milrinone treatment, and was associated with reduction of plasma levels IL-6, IL-8 and IL-10. Plasma concentrations of cAMP were significantly decreased in patients with ANS dysregulation or PE compared with patients with HFMD or BE; however, cAMP levels increased after milrinone treatment. Conclusions These findings suggested decreased different regulatory T populations and cAMP expression correlate with increased EV71 disease severity. Improved outcome after milrinone treatment may associate with increased regulatory T populations, cAMP expression and modulation of cytokines levels.
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Affiliation(s)
- Shih-Min Wang
- Department of Emergency Medicine College of Medicine, National Cheng Kung University and Hospital, Tainan, Taiwan
- Center of Infectious Disease and Signaling Research, National Cheng Kung University, Tainan, Taiwan
- * E-mail: (SMW); (CCL)
| | - I-Chun Chen
- Institute of Basic Medical Sciences, College of Medicine, National Cheng Kung University, Tainan, Taiwan
| | - Yu-Ting Liao
- Center of Infectious Disease and Signaling Research, National Cheng Kung University, Tainan, Taiwan
| | - Ching-Chuan Liu
- Department of Pediatrics, College of Medicine, National Cheng Kung University and Hospital, Tainan, Taiwan
- Center of Infectious Disease and Signaling Research, National Cheng Kung University, Tainan, Taiwan
- * E-mail: (SMW); (CCL)
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Sciaraffia E, Riccomi A, Lindstedt R, Gesa V, Cirelli E, Patrizio M, De Magistris MT, Vendetti S. Human monocytes respond to extracellular cAMP through A2A and A2B adenosine receptors. J Leukoc Biol 2014; 96:113-22. [PMID: 24652540 DOI: 10.1189/jlb.3a0513-302rr] [Citation(s) in RCA: 38] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/23/2023] Open
Abstract
In this study, we test the hypothesis that cAMP, acting as an extracellular mediator, affects the physiology and function of human myeloid cells. The cAMP is a second messenger recognized as a universal regulator of several cellular functions in different organisms. Many studies have shown that extracellular cAMP exerts regulatory functions, acting as first mediator in multiple tissues. However, the impact of extracellular cAMP on cells of the immune system has not been fully investigated. We found that human monocytes exposed to extracellular cAMP exhibit higher expression of CD14 and lower amount of MHC class I and class II molecules. When cAMP-treated monocytes are exposed to proinflammatory stimuli, they exhibit an increased production of IL-6 and IL-10 and a lower amount of TNF-α and IL-12 compared with control cells, resembling the features of the alternative-activated macrophages or M2 macrophages. In addition, we show that extracellular cAMP affects monocyte differentiation into DCs, promoting the induction of cells displaying an activated, macrophage-like phenotype with reduced capacity of polarized, naive CD4(+) T cells into IFN-γ-producing lymphocytes compared with control cells. The effects of extracellular cAMP on monocytes are mediated by CD73 ecto-5'-nucleotidase and A2A and A2B adenosine receptors, as selective antagonists could reverse its effects. Of note, the expression of CD73 molecules has been found on the membrane of a small population of CD14(+)CD16(+) monocytes. These findings suggest that an extracellular cAMP-adenosine pathway is active in cells of the immune systems.
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Affiliation(s)
- Ester Sciaraffia
- Department of Infectious, Parasitic and Immune-Mediated Diseases, and
| | - Antonella Riccomi
- Department of Infectious, Parasitic and Immune-Mediated Diseases, and
| | - Ragnar Lindstedt
- Department of Infectious, Parasitic and Immune-Mediated Diseases, and
| | - Valentina Gesa
- Department of Infectious, Parasitic and Immune-Mediated Diseases, and
| | - Elisa Cirelli
- Department of Infectious, Parasitic and Immune-Mediated Diseases, and Animal Breeding Department, University of Rome "Tor Vergata", Rome, Italy
| | - Mario Patrizio
- Department of Drug Research and Evaluation, Istituto Superiore di Sanità, Rome, Italy; and
| | | | - Silvia Vendetti
- Department of Infectious, Parasitic and Immune-Mediated Diseases, and
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Tsai HC, Wu R. Cholera toxin directly enhances IL-17A production from human CD4+ T cells. JOURNAL OF IMMUNOLOGY (BALTIMORE, MD. : 1950) 2013; 191:4095-102. [PMID: 24043897 PMCID: PMC3825190 DOI: 10.4049/jimmunol.1301079] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/13/2022]
Abstract
The significance of Th17 cells and IL-17A signaling in host defense and disease development has been demonstrated in various infection and autoimmune models. Additionally, the generation of Th17 cells is highly influenced by microbes. However, the specific bacterial components capable of shaping Th17 responses have not been well defined. The goals of this study were to understand how a bacterial toxin, cholera toxin (CT), modulates Th17-dominated response in isolated human CD4(+) T cells, and what are the mechanisms associated with this modulation. CD4(+) cells isolated from human peripheral blood were treated with CT. The levels of cytokine production and specific Th cell responses were determined by ELISA, Luminex assay, and flow cytometry. Along with the decreased production of other proinflammatory cytokines (IFN-γ, TNF-α, and IL-2), we found that CT could directly enhance the IL-17A production through a cAMP-dependent pathway. This enhancement is specific for IL-17A but not for IL-17F, IL-22, and CCL20. Interestingly, CT could increase IL-17A production only from Th17-committed cells, such as CCR6(+)CD4(+) T cells and in vitro-differentiated Th17 cells. Furthermore, we also demonstrated that this direct effect occurs at a transcriptional level because CT stimulates the reporter activity in Jurkat and primary CD4(+) T cells transfected with the IL-17A promoter-reporter construct. This study shows that CT has the capacity to directly shape Th17 responses in the absence of APCs. Our findings highlight the potentials of bacterial toxins in the regulation of human Th17 responses.
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Affiliation(s)
- Hsing-Chuan Tsai
- Center for Comparative Respiratory Biology and Medicine, University of California, Davis, CA95616, U.S.A
| | - Reen Wu
- Center for Comparative Respiratory Biology and Medicine, University of California, Davis, CA95616, U.S.A
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10
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Zhang JH, Hu CW, Zhu YZ, Liu SM, Bai CS, Han YF, Xia SL, Li YF. Effects of norepinephrine on immune functions of cultured splenic lymphocytes exposed to aluminum trichloride. Biol Trace Elem Res 2013; 154:275-80. [PMID: 23775601 DOI: 10.1007/s12011-013-9729-1] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 04/11/2013] [Accepted: 06/05/2013] [Indexed: 11/28/2022]
Abstract
The aim of this study was to investigate the effect of norepinephrine (NE) on spleen lymphocytes exposed to aluminum trichloride (AlCl3). In this experiment, lymphocytes were isolated from spleens of healthy Wistar rats weighing about 130 g and cultured with RPMI-1640 medium containing the final concentration of 0.552 mmol/L AlCl3. NE was added to the cultured cells at the final concentrations of 0 (control group), 0.1 (low-dose group), 1 (mid-dose group), and 10 (high-dose group) nmol/L. No addition of both AlCl3 and NE serviced as blank (BG). The T lymphocyte proliferation; the contents of IL-2, TNF-α, and T lymphocyte subsets; immunoglobulin G (IgG) and intracellular cyclic adenosine monophosphate (cAMP) concentrations; and β2-adrenergic receptor (β2-AR) density were measured at the end of the culture. The result showed that NE decreased T lymphocyte proliferation and the contents of IL-2, TNF-α, and T lymphocyte subsets whereas increased the concentrations of IgG and intracellular cAMP and β2-AR density of the lymphocyte exposed to AlCl3. AlCl3 exposure without adding NE showed the similar impacts on these measures compared with BG. The results suggested that NE aggravated AlCl3 immunotoxicity on the lymphocytes and disordered the immune functions of the lymphocyte through the β2-AR-cAMP signal pathway.
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Affiliation(s)
- Ji-Hong Zhang
- College of Veterinary Medicine, Northeast Agricultural University, Harbin 150030, People's Republic of China
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11
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Tan YV, Abad C, Wang Y, Lopez R, Waschek JA. Pituitary adenylate cyclase activating peptide deficient mice exhibit impaired thymic and extrathymic regulatory T cell proliferation during EAE. PLoS One 2013; 8:e61200. [PMID: 23613811 PMCID: PMC3628797 DOI: 10.1371/journal.pone.0061200] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/21/2012] [Accepted: 03/07/2013] [Indexed: 12/21/2022] Open
Abstract
We have shown that mice deficient in pituitary adenylate cyclase-activating polypeptide (PACAP, gene name ADCYAP1) manifest enhanced sensitivity to experimental autoimmune encephalomyelitis (EAE), supporting the anti-inflammatory actions described for this neuropeptide. In addition to an increased proinflammatory cytokine response in these mice, a reduction in regulatory T cell (Treg) abundance in the lymph nodes (LN) was observed, suggesting altered Treg kinetics. In the present study, we compared in PACAP deficient (KO) vs. wild type mice the abundances and rates of proliferation FoxP3+ Tregs in three sites, the LN, central nervous system (CNS) and thymus and the relative proportions of Th1, Th2, and Th17 effector subsets in the LN and CNS. Flow cytometry analyses revealed a decrease in Treg proliferation and an increased T effector/Tregs ratio in the LN and CNS of PACAP KO mice. In the thymus, the primary site of do novo natural Treg production, the total numbers and proliferative rates of FoxP3+ Tregs were significantly reduced. Moreover, the expression of IL-7, a cytokine implicated in thymic Treg expansion during EAE, failed to increase at the peak of the disease in the thymus and LN of PACAP KO mice. In addition to these Treg alterations, a specific reduction of Th2 cells (about 4-fold) was observed in the lymph nodes in PACAP KO mice, with no effects on Th1 and Th17 subsets, whereas in the CNS, Th1 and Th17 cells were increased and Th2 decreased. Our results suggest that endogenous production of the neuropeptide PACAP protects against EAE by modulating Treg expansion and Th subsets at multiple sites.
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Affiliation(s)
- Yossan-Var Tan
- Semel Institute/Department of Psychiatry, David Geffen School of Medicine, University of California Los Angeles, Los Angeles, California, United States of America
| | - Catalina Abad
- Semel Institute/Department of Psychiatry, David Geffen School of Medicine, University of California Los Angeles, Los Angeles, California, United States of America
| | - Yuqi Wang
- Semel Institute/Department of Psychiatry, David Geffen School of Medicine, University of California Los Angeles, Los Angeles, California, United States of America
| | - Robert Lopez
- Semel Institute/Department of Psychiatry, David Geffen School of Medicine, University of California Los Angeles, Los Angeles, California, United States of America
| | - James A. Waschek
- Semel Institute/Department of Psychiatry, David Geffen School of Medicine, University of California Los Angeles, Los Angeles, California, United States of America
- * E-mail:
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Li J, Lin KW, Murray F, Nakajima T, Zhao Y, Perkins DL, Finn PW. Regulation of cytotoxic T lymphocyte antigen 4 by cyclic AMP. Am J Respir Cell Mol Biol 2012; 48:63-70. [PMID: 23024062 DOI: 10.1165/rcmb.2012-0155oc] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/24/2022] Open
Abstract
Recent studies indicate that cyclic AMP (cAMP) induces cytotoxic T lymphocyte antigen (CTLA) 4. CTLA4 is expressed in T cells, and is a negative regulator of T cell activation. CTLA4 expression is regulated by T cell receptor plus CD28 (adaptive immune signaling) at both the transcriptional and post-transcriptional level. Here, we examine the pathways by which cAMP regulates CTLA4 expression, focusing on transcriptional activation. Elevating intracellular cAMP levels by cell-permeable cAMP analogs, the adenylyl cyclase activator, forskolin, or phosphodiesterase inhibitors increases CTLA4 mRNA expression in EL4 murine T cells and primary CD4(+) T cells. Activation of protein kinase A (using the protein kinase A-selective agonist, N6-phenyladenosine-cAMP), but not exchange proteins activated by cAMP (using the exchange proteins activated by cAMP-selective 8-pCPT-2Me-cAMP), increases CTLA4 promoter activity. Mutation constructs of the CTLA4 promoter uncover an enhancer binding site located within the -150 to -130 bp region relative to the transcription start site. Promoter analysis and chromatin immunoprecipitation assays suggest that cAMP response element-binding is a putative transcription factor induced by cAMP. We have previously shown that CTLA4 mediates decreased pulmonary inflammation in an LPS-induced murine model of acute lung injury (ALI). We observed that LPS can induce CTLA4 transcription via the same cAMP-inducible promoter region. The immunosuppressant, rapamycin, decreases cAMP and LPS-induced CTLA4 transcription in vitro. In vivo, LPS induces cAMP accumulation in bronchoalveolar lavage fluid, bronchoalveolar lavage cells, and lung tissues in ALI. We demonstrate that rapamycin decreases cAMP accumulation and CTLA4 expression in ALI. Together, these data suggest that cAMP may negatively regulate pulmonary inflammatory responses in vivo and in vitro by altering CTLA4 expression.
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Affiliation(s)
- Jinghong Li
- Division of Pulmonary and Critical Care Medicine, Department of Medicine, University of California, San Diego, La Jolla, California, USA
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Becker C, Bopp T, Jonuleit H. Boosting regulatory T cell function by CD4 stimulation enters the clinic. Front Immunol 2012; 3:164. [PMID: 22719741 PMCID: PMC3376463 DOI: 10.3389/fimmu.2012.00164] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/10/2012] [Accepted: 05/31/2012] [Indexed: 01/14/2023] Open
Abstract
Understanding tolerance mechanisms at the cellular and molecular level holds the promise to establish novel immune intervention therapies in patients with allergy or autoimmunity and to prevent transplant rejection. Administration of mAb against the CD4 molecule has been found to be exceptionally well suited for intentional tolerance induction in rodent and non-human primate models as well as in humanized mouse models. Recent evidence demonstrated that regulatory T cells (Treg) are directly activated by non-depleting CD4 ligands and suggests Treg activation as a central mechanism in anti-CD4-mediated tolerance induction. This review summarizes the current knowledge on the role of Treg in peripheral tolerance, addresses the putative mechanisms of Treg-mediated suppression and discusses the clinical potential of harnessing Treg suppressive activity through CD4 stimulation.
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Affiliation(s)
- Christian Becker
- Department of Dermatology, University Medical Center of the Johannes Gutenberg-University, Mainz, Germany
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Mauricio Rueda C, Andrea Velilla P, Rojas M, Teresa Rugeles M. AMPc: una molécula clave en los eventos de regulación inmune y en el control de la replicación del VIH. INFECTIO 2012. [DOI: 10.1016/s0123-9392(12)70058-9] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/25/2022] Open
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15
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Olsen PC, Coelho LP, da Costa JCS, Cordeiro RSB, Silva PMR, Martins MA. Two for one: cyclic AMP mediates the anti-inflammatory and anti-spasmodic properties of the non-anesthetic lidocaine analog JMF2-1. Eur J Pharmacol 2012; 680:102-7. [PMID: 22329902 DOI: 10.1016/j.ejphar.2012.01.040] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/14/2011] [Revised: 01/24/2012] [Accepted: 01/28/2012] [Indexed: 01/23/2023]
Abstract
Inhalation of JMF2-1, an analog of lidocaine with reduced anesthetic activity, prevents airway contraction and lung inflammation in experimental asthma models. We sought to test if the JMF2-1 effects are a consequence of increased intracellular cAMP levels in asthma cell targets, such as smooth muscle cells and T cells. Functional effect of JMF2-1 on carbachol-induced contraction of intact or epithelial-denuded rat trachea was assessed in conventional organ baths. cAMP was quantified by radioimmunoassay in cultured guinea pig tracheal smooth muscle cells, as well as lymph node cells from BALB/c mice, exposed to JMF2-1. We found that JMF2-1 (0.1-1mM) concentration-dependently inhibited epithelium-intact tracheal ring contraction induced by carbachol challenge. The antispasmodic effect remained unaltered following epithelium removal or pretreatment with NG-nitro-L-arginine methyl ester (100μM), but it was clearly sensitive to 9-(tetrahydro-2-furyl) adenine (SQ22,536, 100μM), an adenylate cyclase inhibitor. JMF2-1 (300 and 600μM) also dose-dependently increased cAMP intracellular levels of both cultured airway smooth muscle cells and T lymphocytes. This effect was consistently abrogated by SQ22,536 and reproduced by forskolin in both systems. JMF2-1 induced apoptosis of anti-CD3 activated T cells in a mechanism sensitive to zIETD, indicating that JMF2-1 mediates caspase-8-dependent apoptosis. Furthermore, forskolin also inhibited anti-CD3 induced T cell proliferation and survival. Our results suggest that JMF2-1 inhibits respiratory smooth muscle contraction as well as T cell proliferation and survival through enhancement of intracellular cAMP levels. These findings may help to explain the anti-inflammatory and antispasmodic effects of JMF2-1 observed in previous studies.
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Affiliation(s)
- Priscilla C Olsen
- Laboratory of Inflammation, Oswaldo Cruz Institute, Oswaldo Cruz Foundation, Rio de Janeiro, RJ, Brazil
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Moreno-Fernandez ME, Rueda CM, Velilla PA, Rugeles MT, Chougnet CA. cAMP during HIV infection: friend or foe? AIDS Res Hum Retroviruses 2012; 28:49-53. [PMID: 21916808 DOI: 10.1089/aid.2011.0265] [Citation(s) in RCA: 29] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/14/2022] Open
Abstract
Intracellular levels of cyclic adenosine 3',5'-monophosphate (cAMP) are important regulators of immune cells, partially determining the balance between activation and suppression. In this review, we discuss the mechanisms by which HIV infection increases cAMP levels in T cells, as well as the effect of cAMP on HIV-specific responses and its effect on HIV replication and infection. Results suggest that increased cAMP levels during HIV infection may have a dual and opposite roles. On the one hand, they could have a protective effect by limiting viral replication in infected cells and decreasing viral entry. On the other hand, they could have a detrimental role by reducing HIV-specific antiviral immune responses, thus reducing the clearance of the virus and contributing to T cell dysfunction. Future studies are thus needed to further define the beneficial versus detrimental roles of cAMP, as they could help establish new therapeutic targets to combat HIV replication and/or identify novel ways to boost antiviral immune responses.
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Affiliation(s)
- Maria E. Moreno-Fernandez
- Division of Molecular Immunology, Cincinnati Children's Hospital Research Foundation, Department of Pediatrics, Immunobiology Graduate Program University of Cincinnati, College of Medicine, Cincinnati, Ohio
| | | | - Paula A. Velilla
- Grupo Inmunovirologia, Universidad de Antioquia, Medellin, Antioquia, Colombia
| | | | - Claire A. Chougnet
- Division of Molecular Immunology, Cincinnati Children's Hospital Research Foundation, Department of Pediatrics, Immunobiology Graduate Program University of Cincinnati, College of Medicine, Cincinnati, Ohio
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Klein M, Vaeth M, Scheel T, Grabbe S, Baumgrass R, Berberich-Siebelt F, Bopp T, Schmitt E, Becker C. Repression of cyclic adenosine monophosphate upregulation disarms and expands human regulatory T cells. THE JOURNAL OF IMMUNOLOGY 2011; 188:1091-7. [PMID: 22190184 DOI: 10.4049/jimmunol.1102045] [Citation(s) in RCA: 36] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/19/2022]
Abstract
The main molecular mechanism of human regulatory T cell (Treg)-mediated suppression has not been elucidated. We show in this study that cAMP represents a key regulator of human Treg function. Repression of cAMP production by inhibition of adenylate cyclase activity or augmentation of cAMP degradation through ectopic expression of a cAMP-degrading phosphodiesterase greatly reduces the suppressive activity of human Treg in vitro and in a humanized mouse model in vivo. Notably, cAMP repression additionally abrogates the anergic state of human Treg, accompanied by nuclear translocation of NFATc1 and induction of its short isoform NFATc1/αA. Treg expanded under cAMP repression, however, do not convert into effector T cells and regain their anergic state and suppressive activity upon proliferation. Together, these findings reveal the cAMP pathway as an attractive target for clinical intervention with Treg function.
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Affiliation(s)
- Matthias Klein
- University Medical Center, Institute for Immunology, Johannes Gutenberg-University, 55131 Mainz, Germany
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Regulatory T cells control HIV replication in activated T cells through a cAMP-dependent mechanism. Blood 2011; 117:5372-80. [PMID: 21436067 DOI: 10.1182/blood-2010-12-323162] [Citation(s) in RCA: 91] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/26/2023] Open
Abstract
We hypothesized that regulatory T cells (Tregs) could play a beneficial role during HIV infection by controlling HIV replication in conventional T cells (Tcons). Purified Tregs and Tcons from healthy donors were activated separately. Tcons were infected with the X4 or R5 HIV strains and cultured with or without autologous Tregs. Coculture of Tcons and Tregs resulted in a dose-dependent inhibition of Tcon infection, which was significant when a 1:1 Treg:Tcon ratio was used. Treg suppression of HIV infection was largely mediated by contact-dependent mechanisms. Blockage of cytotoxic T-lymphocyte-associated antigen-4 did not significantly reduce Treg function. In contrast, Tregs acted through cAMP-dependent mechanisms, because the decrease of cAMP levels in Tregs, the blockade of gap junction formation between Tregs and Tcons, the blockage of CD39 activity, and the blockage of protein kinase A in Tcons all abolished Treg-mediated suppression of HIV replication. Our data suggest a complex role for Tregs during HIV infection. Although Tregs inhibit specific immune responses, their inhibition of HIV replication in Tcons may play a beneficial role, particularly during early HIV infection, when the effector immune cells are not yet activated. Such a protective role of Tregs could have a profound impact on infection outcome.
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Cholera toxin impairs the differentiation of monocytes into dendritic cells, inducing professional antigen-presenting myeloid cells. Infect Immun 2010; 79:1300-10. [PMID: 21149590 DOI: 10.1128/iai.01181-10] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/06/2023] Open
Abstract
Cholera toxin (CT) is a potent adjuvant for mucosal vaccination; however, its mechanism of action has not been clarified completely. It is well established that peripheral monocytes differentiate into dendritic cells (DCs) both in vitro and in vivo and that monocytes are the in vivo precursors of mucosal CD103(-) proinflammatory DCs. In this study, we asked whether CT had any effects on the differentiation of monocytes into DCs. We found that CT-treated monocytes, in the presence of granulocyte-macrophage colony-stimulating factor (GM-CSF) and interleukin 4 (IL-4), failed to differentiate into classical DCs (CD14(low) CD1a(high)) and acquired a macrophage-like phenotype (CD14(high) CD1a(low)). Cells differentiated in the presence of CT expressed high levels of major histocompatibility complex class I (MHC-I) and MHC-II and CD80 and CD86 costimulatory molecules and produced larger amounts of IL-1β, IL-6, and IL-10 but smaller amounts of tumor necrosis factor alpha (TNF-α) and IL-12 than did monocytes differentiated into DCs in the absence of CT. The enzymatic activity of CT was found to be important for the skewing of monocytes toward a macrophage-like phenotype (Ma-DCs) with enhanced antigen-presenting functions. Indeed, treatment of monocytes with scalar doses of forskolin (FSK), an activator of adenylate cyclase, induced them to differentiate in a dose-dependent manner into a population with phenotype and functions similar to those found after CT treatment. Monocytes differentiated in the presence of CT induced the differentiation of naïve T lymphocytes toward a Th2 phenotype. Interestingly, we found that CT interferes with the differentiation of monocytes into DCs in vivo and promotes the induction of activated antigen-presenting cells (APCs) following systemic immunization.
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Cholera-like enterotoxins and Regulatory T cells. Toxins (Basel) 2010; 2:1774-95. [PMID: 22069660 PMCID: PMC3153266 DOI: 10.3390/toxins2071774] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/04/2010] [Revised: 06/23/2010] [Accepted: 06/28/2010] [Indexed: 01/25/2023] Open
Abstract
Cholera toxin (CT) and the heat-labile enterotoxin of E. coli (LT), as well as their non toxic mutants, are potent mucosal adjuvants of immunization eliciting mucosal and systemic responses against unrelated co-administered antigens in experimental models and in humans (non toxic mutants). These enterotoxins are composed of two subunits, the A subunit, responsible for an ADP-ribosyl transferase activity and the B subunit, responsible for cell binding. Paradoxically, whereas the whole toxins have adjuvant properties, the B subunits of CT (CTB) and of LT (LTB) have been shown to induce antigen specific tolerance when administered mucosally with antigens in experimental models as well as, recently, in humans, making them an attractive strategy to prevent or treat autoimmune or allergic disorders. Immunomodulation is a complex process involving many cell types notably antigen presenting cells and regulatory T cells (Tregs). In this review, we focus on Treg cells and cholera-like enterotoxins and their non toxic derivates, with regard to subtype, in vivo/in vitro effects and possible role in the modulation of immune responses to coadministered antigens.
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Elevated cyclic AMP levels in T lymphocytes transformed by human T-cell lymphotropic virus type 1. J Virol 2010; 84:8732-42. [PMID: 20573814 DOI: 10.1128/jvi.00487-10] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/12/2023] Open
Abstract
Human T-cell lymphotropic virus type 1 (HTLV-1), the cause of adult T-cell leukemia/lymphoma (ATLL), transforms CD4(+) T cells to permanent growth through its transactivator Tax. HTLV-1-transformed cells share phenotypic properties with memory and regulatory T cells (T-reg). Murine T-reg-mediated suppression employs elevated cyclic AMP (cAMP) levels as a key regulator. This led us to determine cAMP levels in HTLV-1-transformed cells. We found elevated cAMP concentrations as a consistent feature of all HTLV-1-transformed cell lines, including in vitro-HTLV-1-transformed, Tax-transformed, and patient-derived cells. In transformed cells with conditional Tax expression, high cAMP levels coincided with the presence of Tax but were lost without it. However, transient ectopic expression of Tax alone was not sufficient to induce cAMP. We found specific downregulation of the cAMP-degrading phosphodiesterase 3B (PDE3B) in HTLV-1-transformed cells, which was independent of Tax in transient expression experiments. This is in line with the notion that PDE3B transcripts and cAMP levels are inversely correlated. Overexpression of PDE3B led to a decrease of cAMP in HTLV-1-transformed cells. Decreased expression of PDE3B was associated with inhibitory histone modifications at the PDE3B promoter and the PDE3B locus. In summary, Tax transformation and its continuous expression contribute to elevated cAMP levels, which may be regulated through PDE3B suppression. This shows that HTLV-1-transformed cells assume biological features of long-lived T-cell populations that potentially contribute to viral persistence.
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Hadjiyanni I, Siminovitch KA, Danska JS, Drucker DJ. Glucagon-like peptide-1 receptor signalling selectively regulates murine lymphocyte proliferation and maintenance of peripheral regulatory T cells. Diabetologia 2010; 53:730-40. [PMID: 20225396 DOI: 10.1007/s00125-009-1643-x] [Citation(s) in RCA: 104] [Impact Index Per Article: 7.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/28/2023]
Abstract
AIMS/HYPOTHESIS Glucagon-like peptide-1 receptor (GLP-1R) agonists improve glucose control in animals and humans with type 1 diabetes. However, there is little information on the role of the GLP-1R in the immune system. We studied the role of the GLP-1R in immune function in wild-type (WT) and nonobese diabetic (NOD) and Glp1r-/- mice. METHODS Glp1r mRNA expression was examined in sorted immune subpopulations by RT-PCR. The effects of GLP-1R activation were assessed on cAMP production and proliferation, migration and survival of primary immune cells from WT and NOD mice. The ability of primary cells from Glp1r-/- mice to proliferate, migrate or survive apoptosis was determined. Immunophenotyping studies were performed to assess the frequency of immune subpopulations in Glp1r-/- mice. RESULTS Ex vivo activation of the GLP-1R resulted in a modest but significant elevation of cAMP in primary thymocytes and splenocytes from both WT and NOD mice. GLP-1R activation did not increase proliferation of primary thymocytes, splenocytes or peripheral lymph node cells. In contrast, Glp1r-/- thymocytes exhibited a hypoproliferative response, whilst peripheral Glp1r-/- lymphocytes were hyperproliferative in response to mitogenic stimulation. Activation or loss of GLP-1R signalling did not modify apoptosis or chemotaxis in primary lymphocytes. Male Glp1r-/- mice exhibited a significantly lower percentage of peripheral regulatory T cells, although no differences were observed in the numbers of CD4+ and CD8+ T cells and B cells in the spleen and lymph nodes of Glp1r-/- mice. CONCLUSIONS/INTERPRETATION These studies establish that GLP-1R signalling may regulate lymphocyte proliferation and maintenance of peripheral regulatory T cells.
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Affiliation(s)
- I Hadjiyanni
- Department of Medicine, Samuel Lunenfeld Research Institute, Mt Sinai Hospital, 600 University Avenue TCP5-1004, Toronto, ON M5G 1X5, Canada
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Cholera toxin and Escherichia coli heat-labile enterotoxin, but not their nontoxic counterparts, improve the antigen-presenting cell function of human B lymphocytes. Infect Immun 2009; 77:1924-35. [PMID: 19223474 DOI: 10.1128/iai.01559-08] [Citation(s) in RCA: 25] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
B lymphocytes play an important role in the immune response induced by mucosal adjuvants. In this study we investigated the in vitro antigen-presenting cell (APC) properties of human B cells upon treatment with cholera toxin (CT) and Escherichia coli heat-labile enterotoxin (LT) and nontoxic counterparts of these toxins, such as the B subunit of CT (CT-B) and the mutant of LT lacking ADP ribosyltransferase activity (LTK63). Furthermore, forskolin (FSK), a direct activator of adenylate cyclase, and cyclic AMP (cAMP) analogues were used to investigate the role of the increase in intracellular cAMP caused by the A subunit of CT and LT. B lymphocytes were cultured with adjuvants and polyclonal stimuli necessary for activation of B cells in the absence of CD4 T cells. Data indicated that treatment with CT, LT, FSK, or cAMP analogues, but not treatment with CT-B or LTK63, upregulated surface activation markers on B cells, such as CD86 and HLA-DR, and induced inhibition of the proliferation of B cells at early time points, while it increased cell death in long-term cultures. Importantly, B cells treated with CT, LT, or FSK were able to induce pronounced proliferation of both CD4(+) and CD8(+) allogeneic T cells compared with untreated B cells and B cells treated with CT-B and LTK63. Finally, only treatment with toxins or FSK induced antigen-specific T-cell proliferation in Mycobacterium tuberculosis purified protein derivative or tetanus toxoid responder donors. Taken together, these results indicated that the in vitro effects of CT and LT on human B cells are mediated by cAMP.
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Hofer AM, Lefkimmiatis K. Extracellular calcium and cAMP: second messengers as "third messengers"? Physiology (Bethesda) 2008; 22:320-7. [PMID: 17928545 DOI: 10.1152/physiol.00019.2007] [Citation(s) in RCA: 70] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/21/2022] Open
Abstract
Calcium and cyclic AMP are familiar second messengers that typically become elevated inside cells on activation of cell surface receptors. This article will explore emerging evidence that transport of these signaling molecules across the plasma membrane allows them to be recycled as "third messengers," extending their ability to convey information in a domain outside the cell.
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Affiliation(s)
- Aldebaran M Hofer
- Department of Surgery, VA Boston Healthcare System and Brigham & Women's Hospital, Harvard Medical School, West Roxbury, Massachusetts, USA.
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Inhibition of T cell proliferation by cholera toxin involves the modulation of costimulatory molecules CTLA-4 and CD28. Immunol Lett 2007; 115:59-69. [PMID: 18031829 DOI: 10.1016/j.imlet.2007.10.003] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/11/2007] [Revised: 10/04/2007] [Accepted: 10/08/2007] [Indexed: 11/21/2022]
Abstract
Cholera toxin (CT) is known to inhibit the proliferation of murine and human T lymphocytes. In this study we have analysed the mechanisms underlying the inhibitory effect of CT on subpopulations of human CD4+ and CD8+ T lymphocytes. We show that CT dramatically prevents the activation of resting T lymphocytes, whereas it has a minor effect on cells that have been previously activated. Analysis of DNA content of the CT-treated T cells showed an arrest in the G(0)/G(1) phase and this correlated with high expression of the cyclin-dependent kinase inhibitor p27(kip). Moreover, we show that CT up-regulates the expression of the inhibitory molecule CTLA-4 in naïve, effector and memory resting CD4+ T cells and in resting CD8+ T lymphocytes. The regulation of CTLA-4 expression by CT is at the transcriptional level. Indeed, in cells treated with CT we observed an increase of two mRNA variants coding for the membrane and the soluble CTLA-4 molecules. In parallel with the up-regulation of the inhibitory CTLA-4, CT down-modulates the costimulatory molecule CD28 on CD4+ and CD8+ resting T cells. The increased expression of CTLA-4 played a role in controlling T cell activation and function as blocking anti-CTLA-4 F(ab')(2) mAbs partially inhibited anti-CD3 mAbs induced proliferation. These findings show that the inhibition of T cell proliferation by CT affects early stages of the T cell activation and involves the modulation of costimulatory molecules CTLA-4 and CD28 on resting T cells.
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